MULTIPLE CHOICE QUESTIONS WITH ANSWERS ON WIRELESS SENSOR NETWORKS

WIRELESS SENSOR NETWORKS

1

CHAPTER 1: INTRODUCTION

1>MEMS stands for__________

2>A sensor network is subject to a unique set of resource constraints such as

a: finite on-board battery power

b: limited network communication bandwidth

Ans: ________ (a/b/both)

3>In a typical sensor network, each sensor node operates unethered and has a microprocessor and

a small amount of memory for signal processing and task scheduling (true/false)__________

4>Each node is equipped with one or more sensing devices such as acoustic microphone arrays,

video or still cameras, infrared, seismic or magnetic sensors (true/false)__________

5>Information collected by and transmitted on a sensor network describes conditions of physical

environments and requires advanced query interfaces and search engines to effectively support

user-level functions (true/false)__________

6>___________routes user queries or commands to appropriate nodes in a sensor network

(bridge/gateway)

7>Communicating 1 bit over the wireless medium at short ranges consumes ___________energy

than processing that bit (less/more)

8>For the Sensoria sensors and Berkeley motes, the ratio of energy consumption for communication

and computation is in the range of _____to______ (100/1000/10000)

9>A sensor network is designed to collect information from a___________ environment

(logical/physical)

10>Table1.1___________

11>It is more appropriate to address nodes in a sensor network by_____ than by______ (IP

address/physical properties)

12>Mobility and instability in wireless links prevent the use of many existing edge network gateway

protocols for internetworking IP and sensor networks (true/false)__________

13>The challenges we face in designing sensor network systems and applications include

a: limited hardware

b: limited support for networking

c: limited support for software development

Ans: ___________ (a/b/c/all)

14>Match the following

Limited hardware: the tasks are typically real-time and massively distributed,

involve dynamic collaboration among nodes, and must handle

multiple competing events

Limited support for

networking:

each node has limited processing, storage and communication

capabilities, and limited energy supply and bandwidth

Limited support for

software

development:

the network is peer-to-peer , with a mesh topology and

dynamic, mobile and unreliable connectivity

15>Following are advantages of sensor network

a: energy advantage

b: detection advantage

Ans: ___________ (a/b/both)

16>Dense networks of distributed communicating sensors can improve SNR by reducing average

distances from sensor to source of signal or target (true/false)__________

17>The greatest advantage of networked sensing are in improved___________

(robustness/scalability/both)

18>A___________ sensing system is inherently more robust against individual sensor node or link

failures, because of redundancy in the network (centralized/decentralized)

19>Because of the unique attenuation characteristics of RF signals, _____network provides a

significant energy saving over ______network for the same distance (single hop/multi hop)


2

20>The RF attenuation model near the ground is given by

a: Preceive ¤ Psend/r

b: Psend ¤ Preceive/p

Ans: ___________ (a/b/either)

21>In above expression, alpha is typically in the range of__to___ (2/3/4/5)

22>The power advantage of an N-hop transmission versus a single hop transmission over the same

distance Nr is

a: nrf=N(alpha-1)

b: nrf=N(alpha+1)

Ans: ___________ (a/b/both)

23>In above expression, ___________N gives a larger power saving due to the consideration of RF

energy alone (smaller/larger)

24>Using more nodes increases

a: the cost

b: the power consumption of components

Ans: ___________ (a/b/both)

25>Each sensor has a finite sensing range, determined by the___________ floor of the sensor

(ground/noise)

26>Densor sensor field improves the odds of detecting a signal source within the range

(true/false)___________

27>Once a signal source is inside the sensing range of a sensor, further increasing the sensor

density ___________the average distance from a sensor to the signal source, hence improving the

SNR (decreases/increases)

28>wrt the acoustic sensing case in a two-dimensional plane, the acoustic power received at a

distance r is given by

a: Psend ¤ Precieve/r*r

b: Preceive ¤ Psource/r*r

Ans: ___________ (a/b/either)

29>Wrt acoustic sensing case in a two-dimensional plane, the SNR is given by

a: SNR=10logPsource+10logPnoise+20logr

b: SNR=10logPsource-10logPnoise-20logr

Ans: ___________ (a/b/either)

30>The SNR advantage of the denser sensor network is given by

a: nsnr=20logk

b: nsnr=10logk

Ans: ___________ (a/b/either)

31>An increase in sensor density by a factor of k improves the SNR at a sensor by ___________db

(10logk/20logk)

32>A sensor network is designed to perform a set of high level information processing tasks such as

a: detection

b: tracking

c: classification

Ans: ___________ (a/b/c/all)

33>Following are sample commercial and military applications include

a: environmental monitoring

b: industrial sensing and diagnostics

c: infrastructure protection

d: battlefield awareness

e: context aware computing

Ans: ___________ (a/b/c/d/e/all)


environmental monitoring : intelligent home, responsive environment

Industrial sensing and diagnostics : multi-target tracking

Infrastructure protection : power grids, water distribution

Battlefield awareness : traffic, habitat, security

Context aware computing : appliances, factory, supply chains


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35>If every sensor has some data that it needs to send to another node in a network, then per node

throughput scales as___________{sqrt(N) or 1/sqrt (N)}

36>As the number of nodes___________, every node spends almost all of its time forwarding

packets of other nodes (decreases/increases)

37>CSIP stands for___________

38>___________refers to signal and information processing problems dominated by the issue of

selecting embedded sensors to participate in an information processing task (CSIP/CCIP)

39>___________is an interdisciplinary research area that draws on contributions from signal

processing, networking and protocols, databases and information management, distributed

algorithms, and embedded systems and architecture (wireless networks/sensor networks)


sensor: routing of data based on geographical attributes such as locations

or regions

sensor node: the process of determining a network path from a packet source

node to its destination

network

topology:

approaches that name, route or access a piece of data via

properties that are external to a communication network

routing: a transducer that converts a physical phenomenon that may be

further manipulated by other apparatus

data centric: a basic unit with on-board sensors, processor, memory, wireless

modem and power supply

geographic

routing:

a connectivity graph where nodes are sensor nodes and edges are

communication links


In-network: the process of discovering the existence of a physical

phenomenon

Collaborative

processing:

either high-level system tasks which may include sensing,

communication, processing and resource allocation or application

tasks which may include detection, classification , localization or

tracking

State: a condition of the information caused by noise in sensor

measurements or lack of knowledge in models

Uncertainty: a snapshot about a physical environment or a snapshot of the

system itself

Task: sensors cooperatively processing data from multiple sources in

order to serve a high level task

Detection: a style of processing in which the data is processed and combined

near where the data is generated


Classification: the assignment of sensors to a particular task and the control of

sensor state for accomplishing the task

Localization &

tracking:

services such as time synchronization and node localization that

enable applications to discover properties of a node and the nodes

to organize themselves into a useful network

Value of

information:

resources include sensors, communication links, processors , on-

board memory and node energy reserves

Sensor tasking: the estimation of the state of a physical entity such asa physical

phenomenon or a sensor node from a set of measurements

Resource: a mapping of data to a scalar number, in the context of the

overall system task and knowledge

Node services: the assignment of class labels to a set of physical phenomena

being observed


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Data storage: the abstract characterization of system properties

Embedded OS: a measurable quantity that describes how well the system is

performing on some absolute scale

System

performance

goal:

sensor information is stored, indexed and accessed by

applications

Evaluation

metric:

the run-time system support for sensor network applications

ANSWERS

1>Micro Electro Mechanical System

2>both

3>T

4>T

5>T

6>gateway

7>more

8>1000 to 100000

9>physical

10>

11>physical properties, IP address

12>T

13>all

14>1-b 2-c 3-a

15>both.

16>T

17>Both

18>decentralised

19>multihop, single hop

20>a

21>2-5

22>a

23>larger

24>both

25>noise

26>T

27>decreases

28>b

29>b

30>b

31>10logk

32>all

33>all

34>1-d 2-e 3-c 4-b 5-a

35>1/sqrt(N)

36>increases

37>Collaborative Signal & Information Processing

38>CSIP

39>sensor networks

40>1-d 2-e 3-f 4-b 5-a 6-c

41>1-f 2-e 3-d 4-c 5-b 6-a

42>1-f 2-d 3-e 4-a 5-c 6-b

43>1-c 2-d 3-a 4-b


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CHAPTER 2: CANONICAL PROBLEM –

LOCALIZATION AND TRACKING

1>Localizing and tracking moving objects is an essential capability for a sensor network in many

practical applications (true/false)__________

2>A central problem for CSIP is to dynamically define and form sensor groups based on__________

(task requirements/resource availability/both)

3>A sensor network can be defined as an abstract tuple G=<V, E, Pv, Pe> where

__specifies nodes, ___specifies link connectivity, __is a set of functions that characterizes the

properties of each node and ___specifies properties of each link

4>DOA stands for__________

5>__________is a distributed physical quantity such as temperature, pressure or optical flow across

a region of space (area/field)

6>A tracking task can be formulated as a constrained optimization problem <G, T, W, Q, J, C>

where__is the sensor network , __is a set of targets, __is a signal model for how target signals

propagate and attenuate in the physical medium, __denotes a set of user queries, __specifies an

objective function defined by task requirements and__ specifies a set of constraints

7>In wireless sensor networks, some of the information defining the objective function and

constraints is available only at___________ (compile time/run time)

8>The position estimation may be accomplished by

a: triangulation computation

b: least square computation

Ans: ___________ (a/b/either)

9>Bayesian estimation can be used for position estimation (true/false)___________

10>When the two targets move close to a target track, ___________problem has to be addressed

(data relationship/data association)

11>Tracking scenario raises following fundamental information processing issues

a: in collaborative processing, the issue of target detection, localization, tracking and sensor tasking

and control

b: in networking, the issues of data naming , aggregation and routing

c: in databases, the issues of data abstraction and query optimization

d: in human-computer interface, the issues of data browsing , search and visualization

e: in infrastructure services, the issues of network initialization and discovery, time ad location

services, fault management and security

Ans: ___________ (a/b/c/d/e/all)

12>Give an expression relating zi, ai, x, wi , and Ans: __________

13>To uniquely determine the location on a two-dimensional plane, one needs alleast

___________independent distance measurements (two/three)

14>TDOA stands for___________

15>___________determines the significance of the contribution of each sensor

a: geometry of the sensor placement

b: distance to the signal source

Ans: __ (a/b)

16>The goal of localization or tracking is to obtain a good estimate of the target state from the

measurement history (true/false)__________

17>We refer to the___________ distribution as the current belief (priori/posterior)

18>The relationship between the posterior distribution p (x|z), the priori distribution p (x) , and the

likelihood function p (z|x) is given by Bayes Theorem

a: p (x|z)=p (z|x)p (x)/p (x)

b: p (x|z)=p (z|x)p (x)/p (z)

Ans: ___________ (a/b/either)

19>In above expression, ____is the marginal distribution, which is also called the normalizig

constant{p (x) or p (z)}_______


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20>MMSE stands for___________

21>A commonly used estimator in the standard estimation theory is the___________

(MEMS/MMSE)

22>The___________ algorithm is inefficient in utilizing the communication resources

(centralized/distributed)

23>From the processing point of view, the complexity of the___________ algorithm scales linearly

with K, and hence is prohibitive for large networks (centralized/distributed)

24>In___________ filter, the belief distributions and error models are Gaussians and the system

dynamics model is linear (kalman/particle)

25>In following ways we can approximate an arbitrary belief state regarding the targets

a: we can approximate the belief by a family of distributions

b: we can approximate the belief by weighted point samples

Ans: ___________ (a/b/both)

26>PMF stands for___________

27>We can approximate the belief by weighted point samples .Following are examples of this

approximation

a: discretizing the subset of S by a grid

b: the particle filter approximation of distribution

c: the kalman filter approximation of distribution

Ans: __________ (a/b/c/all)

28>A variant of belief approximation by weighted point samples is to partition S and assign a

probability value to each region which is called ___________type approach (histogram/heuristic)

29>The belief approximation by weighted point samples is called__________

(parametric/nonparametric)

30>The belief approximation by a family of distribution is called___________

(parametric/nonparametric)

31>If we must pass the belief to a remote sensor, we are faced with the following trade off.

Representing the true belief by a______ approximation with relatively few parameters will result in a

poor approximation of the belief state but with the benefit that fewer bits need to be transmitted. On

the other hand, representing the true belief by_____ approximation will result in a more accurate

approximation of the belief at the cost of more transmitted bits (parametric/nonparametric)

32>Gaussian approximation is example of___________ approximation (parametric/nonparametric)

33>In the___________ design, the robustness of the tracker may suffer from occasional leader

node attrition (moving leader/single moving)

34>The___________ design can be used for tracking multiple targets in a sensor field, with one

leader-node tracking each target (moving leader/single moving)

35>The belief state can be stored in a distributed fashion across a section of sensor nodes. This is

attractive from the___________ point of view (robustness/security)

36>___________is key problem in designing distributed CSIP applications (information

representation/storage/ access/all)

37>While defining a unifying architecture for sensor networks is still an open problem, a key

element of such an architecture is the principled interaction between the______ &_____layers

(application/transport/network)

38>Tracking multiple interacting targets distributed over a geographical region is significantly more

challenging for following reasons

a: curse of dimensionality

b: mapping to distributed platforms

Ans: ___________ (a/b/both)

39>The presence and interaction of multiple phenomena cause the dimension of the underlying

state spaces to ___________ (decrease/increase)

40>To ensure the ___________of the system, the communication and computation should be

localized to relevant sensors only (responsiveness/scalability/both)

41>The key idea in the state-space factorization is to decouple information in a state space

into___________ information (location/identity/both)

42>The tracking problem can be solved separately by______ which requires frequent local

communication, and by_____ which requires less frequent, longer range communication (location

estimation/identity management)


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43>Following approaches can be used for tracking multiple objects

a: state space decomposition

b: data association

Ans: ___________ (a/b/both)

44>In___________ approach, the target location and identity information are coupled and

processed in the same space (state space decomposition/ data association)

45>To address the data association problem, following methods can be used________

(MHT/JPDA/both)

46>MHT stands for___________

47>JPDA stands for___________

48>_____forms and maintains multiple association hypotheses. On the other hand,

______evaluates the association probabilities and combines them to compute the state estimate

(MHT/JPDA)

49>The distributed ___________filter is a global method, requiring each sensor node to

communicate its measurement to a central node, where estimation and tracking are carried out

(kalman/particle)

50>In___________ filter method, sensing is distributed while tracking is centralized

(kalman/particle)

51>Replicated information is one of the serious problem in distributed tracking, whether the tracking

is about a single target or multiple targets (true/false)___________

52>Following are sources of information double counting

a: due to loopy propagation of evidence in a network

b: due to multiple sensor nodes observing a single target and reporting multiple detections

Ans: ___________ (a/b/both)

53>Following are common types of sensors for tracking

a: acoustic amplitude sensors

b: DOA sensors

Ans: ___________ (a/b/both)

54>DOA stands for___________

55>___________sensor node measures sound amplitude at the microphone and estimates the

distance to the target based on the physics of sound attenuation (acoustic DOA/acoustic amplitude)

56>___________sensor is a small microphone array. Using beam forming techniques, it can

determine the direction from which the sound comes, that is, the bearing of the target (acoustic

DOA/acoustic amplitude)

57>______sensors estimate distance based on received signal strength or TOA, while_____ sensors

estimate signal bearing based on TDOA (range/DOA)

58>for sensor network applications, a sensor may be characterized by properties such as cost, size,

sensitivity, resolution, response time, energy usage and ease of calibration & installation

(true/false)___________

59>RMS stands for___________

60>Assuming that the sound source is a point source and sound propagation is lossless and

isotropic, RMS amplitude measurement z is related to the sound position x by

Ans: ___________

61>___________sensing provides a range estimate (frequency/amplitude)

62>___________algorithms are commonly used in radar, speech processing and wireless

communication to enhance signals received at an array of sensors (beam forming/bayesian state)

63>The relative time delay between two sensors with a spacing d can be expressed as a function of

the bearing angle given by

a: tm= (d/c)sin

b: tm= (c/d)sin

Ans: ___________

64>Following methods are examples of DOA estimation algorithms___________ (least

squares/maximum likelihood/both)

65>___________method solves for target bearing and location by estimating first the time

difference of arrival at a set of sensors and then the source location (least squares/maximum

likelihood)


8

66>___________method typically converts a set of signals from time domain to frequency domain

and then performs a possibly multidimensional search to find the peak in the correlation spectra

(least squares/maximum likelihood)

67>_____method can be applied to both near and far field problems whereas______ method is

particularly useful for near field problems in which the target is relatively close to the sensors

compared with the sensor spacing (least squares/maximum likelihood)

68>In DOA sensor, The likelihood function is given by

Ans: ___________

69>The DOA estimate is_____ reliable in the medium distance range and is______ reliable when

the sound source is too close or far away from the microphone array (less/more)

70>wrt DOA sensor, in the_____ field, the planar wave assumption is violated. In the______ field,

the SNR is low, and he DOA estimation may be strongly influenced by noise and fail to converge to

the correct angle (near/far)

71>Following are some of the commonly used measures of performance

a: delectability

b: accuracy

c: scalability

d: survivability

e: resource usage

Ans: ___________ (a/b/c/d/e/all)


Delectability: what is the amount of resources that each task consumes

Accuracy: how does the system perform in the presence of node or link

failures as well as malicious attacks

Scalability: this may be measured by sensor coverage, detection resolution,

dynamic range or response latency

Survivability: this is typically characterized in terms of tracking errors or detection

and classification errors

Resource

usage:

how does a specific property of the system vary as the size of the

network, the number of physical stimuli or the number of active

queries increases

73>For___________ problems, performance is typically measured by false alarms and misses

(detection/classification/tracking/all)

74>For___________ problem, performance goals and measures can be stated in terms of target

and system parameters (detection/classification/tracking/all)

75>_____occurs when the outcome is incorrectly predicted as a positive when it is in fact a

negative.______ is when the outcome is incorrectly labeled as a negative when in fact it is a positive

(false negative/false positive)


Source SNR : percentage of runs of a full scenario where continuity

of vehicle identity is

not correctly maintained

Obstacle density : the number of hours of target tracking versus the total

number of node hours

in fully awake mode for the entire network

Network sleep efficiency : this may be measured by the probability of LOS

obstruction for a randomly

placed target-sensor pair

Percentage of track loss : this is measured as the SNR at a reference distance

from the signal source

___________

77>For an acoustic source, ___________is defined as the log ratio of SPL of source at the reference

distance over SPL of background noise (source SNR/receiver SNR)


9


Detection of robustness : active lifetime, sleep lifetime, sleep efficiency

Detection spatial resolution : link capacity

Detection latency : %node loss

Classification robustness : sensor coverage area, target maneuvers, obstacle

density

Track continuity : source SNR

System survivability : link delay

Cross-node DOA estimation : inter-target spacing

Power efficiency :

ANSWERS

1>T

2>both

3>V,E,Pv,Pe

4>Direction-Of-Arrival

5>field

6>G, T, W, Q, J, C

7>run time

8>both

9>T

10>data association

11>all

12>z = h(x , )

13>3

14>Time Difference Of Arrival

15>both

16>T

17>posterior

18>b

19>p(z)

20>Minimum Mean Squared Error

21>MMSE

22>centralized

23>centralized

24>Kalman

25>both

26>Probability Mass Function

27>a, b

28>histogram

29>non parametric

30>parametric

31>parametric, non-parametric

32>parametric

33>single moving

34>moving leader

35>robustness

36>all

37>application, networking

38>both

39>increase

40>both

41>both

42>location estimation, identity management

43>both

44>data association

45>both


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46>Multiple Hypothesis Tracking

47>Joint Probabistic Data Association

48>MHT,JPDA

49>Kalman

50>kalman

51>T

52>both

53>both

54>Direction of arrival

55>acoustic amplitude

56>acoustic DOA

57>range, DOA

58>T

59>Root Mean Square

60>z=a/x- + w

61>amplitude

62>beam forming

63>a

64>both

65>least square

66>ML(maximum likelihood)

67>ML

68>

69>more, less

70>near, far

71>all

72>1-c 2-d 3-c 4-b 5-a

73>dtection, classification

74>tracking

75>false positive, false negative

76>1-d 2-c 3-b 4-a

77>source SNR

78>1-e 2-g 3-b 4-e 5-d 6-c 7-b 8-a


11

CHAPTER 3: NETWORKING SENSORS

1>Networking allows geographical distribution of the sensor nodes and their placement close to

signal sources (true/false)__________

2>Radio communication is the most expensive operation a node performs in terms of energy usage,

and thus it must be used sparingly and only as dictated by the task requirements

(true/false)__________

3>Sensor networks are typically deployed in an adhoc manner (true/false)__________

4>Wireless communication between nodes utilizes radio links (true/false)__________

5>Within the coverage range, communication is by__________ (multicast/broadcast)

6>UDG stands for___________

7>Nodes operate unethered and have limited power resources (true/false)___________

8>For communication, the main consideration is that communication paths consists of many short

hops can be___________ energy efficient than paths using a few long hops (less/more)

9>Networking involves multiple layers in the protocol stack (true/false)___________

10>___________sub-layer manages access to the physical network medium, and its fundamental

goal is to reduce or avoid packet collisions in the medium (MAC/LLC)

11>Following characteristics of wireless sensor networks point to the need for a specialized MAC

protocol

a: the issues of fairness of the node level are much less important than overall application

performance

b: most sensor nodes are idle much of the time

c: In-network processing can greatly improve bandwidth utilization

d: the assumed lack of mobility and therefore the relatively fixed neighborhood of each node can be

exploited in medium access protocol design

e: issues of energy efficiency, scalability and robustness remain paramount

Ans: ___________ (a/b/c/d/e/all)

12>Following MAC protocols have been developed for wireless voice and data communication

networks

a: TDMA

b: FDMA

c: CDMA

d: CSMA

e: WLAN

Ans: __________ (a/b/c/d/e/all)

13>The main goal of the ___________is to reduce energy waste caused by idle listening, collisions,

overhearing and control overhead (S-MAC protocol/IEEE802.15.4 standard)

14>The S-MAC protocol includes following major components

a: periodic listen and sleep

b: collision avoidance

c: overheating avoidance

d: message passing

Ans: ___________ (a/b/c/d/all)

15>In the S-MAC protocol, ___________is designed to reduce energy consumption during the long

idle time when no sensing events happen, by turning off the radio periodically (message

passing/periodic listen and sleep)

16>DCF stands for__________

17>___________in S-MAC is similar to the DCF for IEEE802.11 adhoc mode using an RTS/CTS

exchange (overhearing avoidance/collision avoidance)

18>___________defines both the physical and MAC layer protocols for most remote monitoring and

control as well as sensor network applications (S-MAC protocol/IEEE802.15.4 standard)

19>___________is an industry consortium with the goal of promoting the IEEE802.15.4 standard

(bluetooth/zigbee)


12

20>Following are features of Zigbee

a: it is an industry consortium with the goal of promoting the IEEE802.15.4 standard

b: it ensures interoperability by defining higher network layers and application interfaces

c: it is optimized for low data throughput up to 115.2 kbps, with simple or no Qos

support___________

21>Unlike_____, ______achieves its power efficiency from both the physical and MAC layers (S-

MAC protocol/IEEE802.15.4 standard)

22>Following are essential characteristics of current sensor network

a: the nodes have only modest processing power and memory

b: network links and nodes can come and go

Ans: ___________ (a/b/both)

23>___________type protocols only broadcast topology changes to neighbors, but because of that

they converge slowly (link state/distance vector)

24>Proactive protocols of the ___________type need to broadcast to the entire network topology

changes when these are locally detected (LS/DV)

25>Following strategies have been suggested to mitigate the demands of the dynamic changes on

the network

a: the frequency of topology updates to distant parts of the network can be reduced , as in fisheye

state routing

b: reactive protocols can be used instead, constructing paths on demand only. Eg: DSR, AODV

Ans: ___________ (a/b/both)

26>DSR stands for___________

27>AODV stands for___________

28>Following are examples of reactive protocol___________ (DSR/AODV)

29>information providers and information seekers need to be matched usig data attributes and not

hard network addresses (true/false)___________

30>Examples of data attributes may include

a: node's location

b: node's type of sensors

c: certain range of values in a certain type of sensed data

Ans: ___________ (a/b/c/all)

31>The network must be both a database that can be queried about the world state, which is

called_____ operation and an entity that can actively initiate an action when something of interest is

sensed which is called______ (push/pull)

32>Aim of the routing protocols is to deliver packets to nodes or areas of the network specified by

their geographic location (true/false)___________

33>It may be more economical to use a ___________transmission radius for nodes in areas of high

node density (larger/smaller)

34>It may be more economical to use a smaller transmission radius for nodes in areas of high node

density, w/o sacrificing adequate network connectivity. This is the issue of___________ (topology

control/traffic control)

35>In___________ routing, among the neighbors y of x closer to d than x, pick the one closest to d

(greedy distance/compass)

36>In ___________ routing, among the neighbors y of x that make an angle dxy< , we pick one

that minimizes the angle dxy (greedy distance/compass)

37>If G contains the Delaunay triangulation of V, then the ___________protocol always works

(greedy distance/compass/both )

38>___________routing has guaranteed delivery when G Is the Delaunay triangulation of V (greedy

distance/compass/both)

39>___________routing states that "start in the face of G just beyond s along sd and walk around

that face. Stop if d is reached or if the segment sd is about to be crossed. In the latter case, cross

over into the next face of G along sd and repeat the process" (greedy distance/compass /convex

perimeter)

40>OFR stands for ___________

41>In___________ protocol, after we go around a face F, we continue into a new face F' not from

the farthest with F, but instead from the vertex of F closest to d (OFR/perimeter)

42>OAFR stands for___________


13

43>We can start with a small guess and double it every time we fail to reach d with our current

guess, until d is reached. This defines adaptive versions of the perimeter protocol

called___________ (OAFR/adaptive perimeter)

44>We say that a sub-graph H of G is a ___________for G if H is a graph on the same vertex set as

G, is missing some of the edges of G, yet there is a constant 'a', a>=1, such that for any pair of

vertices u and v the length of the shortest path between u and v in H is at most 'a' times that of the

length of the shortest path between u and v in G. The constant 'a' is called the__________ (stretch

factor/spanner)

45>A number of the standard geometric graph constructions for a set of points V can be used to

define planarizations of the graph G. The most common such constructions are

___________ (Gabriel/RNG/both)

46>RNG stands for___________

47>In___________, the edges xy is introduced if the lune is free of other nodes (Gabriel/RNG)

48>In___________, the edges xy is introduced if the circle of diameter xy is free of other nodes_

(Gabriel/RNG)

49>_____is a super-graph of the_______ (Gabriel/RNG/both

50>The Delaunay triangulation is known to be___________ of the complete Euclidean graph on V

(planar/spanner/both)

51>RDG stands for___________

52>LDel Stands for___________

53>While ___________protocols are extremely simple, they can get stuck in local minima. In

contrast, ______protocols can provide guaranteed delivery, but require both preprocessing and a

significantly more complex routing algorithm (greedy distance/perimeter)

54>GPSR stands for___________

55>GPSR protocol is a mixture of___________ (greedy distance/perimeter/both)

56>Normally GPSR defaults to ______routing. When it gets stuck, then the_____ protocol is

invoked but only until a node is encountered that is closer to the destination (greedy

distance/perimeter)

57>TBF stands for___________

58>Another form of geographical routing, applicable in a number of dense node coverage settings,

is to specify an ideal curve that a packet should follow, as opposed to the packet's final destination.

This is called___________ (OFR/TBF)

59>___________routing is a method for bringing together information seekers and information

providers in a sensor network (greedy distance/rumour)

60>Following aspects of the energy cost in a sensor network make it challenging to reason about

optimizing energy

a: multi-hop communication can be more efficient than direct transmission

b: when a node transmits, all other nodes within range can hear

Ans: ___________ (a/b/both)

61>Multi-hop communication can be_____ efficient than direct transmission (less/more)

62>The nodes communicate using radio links, where the signal amplitude drops with distance

according to a power law of the form_____ where typically 2<=a<=5{ O (ra) or O (1/ ra)}

______

63>In ___________problem, our goal is to find a schedule of broadcasts and retransmissions that

allows the message to reach all nodes while minimizing the total energy expended (minimum energy

broadcast/maximum energy multicast)

64>MST stands for___________

65>The broadcast nature of radio transmissions changes the minimum energy broadcast problem,

as node u transmitting to reach another node v is also reaches all nodes closer than v at no extra

cost. This is called__________ (wireless broadcast advantage/wireless multicast advantage)

66>The minimum energy broadcast problem for both general and geometric graphs is_______

complete (PN/NP)

67>In the worst case , the MST based algorithm gives a broadcast tree whose total energy usage is

between ___&___times the minimum needed (6/12/18)

68>The key idea that establishes the constant factor approximation is a proof that the minimum

energy required for the broadcast problem can be bounded from below by a constant times the

energy cost of the MST based broadcast tree (true/false)___________


14

69>BIP stands for___________

70>The BIP works like MST algorithm of___________, adding nodes to the broadcast tree one at a

time, starting with the source (kruskal/prim)

71>GEAR stands for ___________

72>The goal of___________ is to efficiently route a message to a geographic region while at the

same time performing load balancing on the nodes used and thus avoiding energy depletion

(GEAR/GPSR)

73>The GEAR protocol operates in following phases

a: deliver the packet to a node in the desired region

b: distribute the packet within the region

Ans: ___________ (a/b/both)

74>During the ___________ phase, GEAR behaves like a unicast protocol routing the message to

the centroid d of the region R except that it considers the energy resources of each node as well

(delivery/distribution)

75>LRTA stands for___________

76>GEAR provides a__to__% increase in the number of packets transmitted before network

partition, __% increase in the number of connected pairs of nodes after network partition, and the

average increase in the path length taken by a packet due to load balancing was between__&__

(25/45/50/100)

77>The second phase of GEAR deals with packet distribution within the destination region R, once

the packet has reached a node x in the region. One of the following strategies can be used here

a: recursive geographic forwarding

b: restricted flooding

Ans: ___________ (a/b/both)

78>___________refers to a process of recursively partitioning the region R into quadrants and then

forwarding the packet from x to the centroid of each quadrant (restricted flooding/recursive

geographic forwarding)

79>___________refers to the initiating a broadcast flooding process from x that is clipped at the

boundary of R (restricted flooding/recursive geographic forwarding)

80>While____________ has the "wireless multicast advantage", it may till prove wasteful when the

region R is densely populated by nodes and the same packet reaches a node multiple times

(restricted flooding/recursive geographic forwarding)

81>In directed diffusion, nodes requesting information are called___ while those generating

information are called___. Records indicating a desire for certain type of information are called_____

(interests/sinks/sources)

82>wrt directed diffusion, ___________attribute field indicates the frequency with which the sink

wishes to receive information about objects matching the other record attributes

(duration/interval/timestamp)

83>wrt directed diffusion, the period of validity of an interest is encoded in its___________

attribute (duration/interval/timestamp)

84>In directed diffusion, ___________generate information request tasks or interests , that diffuse

through the sensor network (sources/sinks)

85>An essential component of directed diffusion is the use of___________ associated with each

interest cache entry, used to direct and control information flowback to the sink (gradient/gateway)

86>In directed diffusion, a gradient is typically derived from the frequency with which a

___________requests repeated data about an interest (source/sink)

87>In data____ type, all communications happened because of the sink's request while in data

_______type, directed diffusion lets sensor nodes trigger event propagation when they detect

something that they believe might be of interest to potential sinks (push/pull)

88>Directed diffusion provides a general-purpose communication mechanism for sensor networks

(true/false)___________

89>Directed diffusion is___________ centric in its network view and performs all routing decisions

through local, neighbor-to-neighbor interactions (state/node)

90>Directed diffusion provide a___________ routing technique, discovering routes between

information sources and sinks as needed (proactive/reactive)

91>Directed diffusion can effectively suppress duplicate events and perform in-network information

aggregation (true/false)___________


15

92>There are may situations in which, because the amount of data to be exchanged is small, the

quality of the paths does not matter so much. In such situations, ___________routing can be used

(rumour/reactive)

93>In___________ routing, in order to get sources and sinks to meet each other, we must spread

information from each regions of the sensor field, so that the two growing regions eventually

intersect (rumour/reactive)

94>Related to rumour routing is the___________ query answering mechanism (ACQUIRE/ACCESS)

95>In rumor routing, ___________approach is most appropriate for situations when we need to

process one-shot complex queries, whose answers depend on information obtained in several nodes

of the network (ACQUIRE/ACCESS)

96>wrt rumour routing, the idea of the ___________system is to elect a leader node whose goal is

to compute the answer to the query (ACQUIRE/ACCESS)

97>IDSQ stands for___________

98>GHT stands for___________

99>GHT is a robust protocol (true/false)___________

100>One of the most elegant aspects of GHT is the way that it exploits features of the___________

routing protocol accomplish its goal (GEAR/GPSR)

101>A nice feature of the perimeter refresh protocol is that it helps to recover from node failures


102>In wireless sensor network, the issues of fail utilization of networking resources at the node

level are__________ important than just accomplishing the overall goal(less/more)

103>What is important to the sensor network is the information the nodes contain, not the nodes

themselves (true/false)__________

104>In wireless sensor networks, nodes are ephemeral i.e. they can be destroyed, be asleep or die

from malfunction or battery depletion (true/false)__________

105>Preservation of energy is of paramount concern in wireless sensor network


106>Network for sensor networks is ____centric but not ______centric (node/data)

107>GHT uses a perimeter refresh protocol

a: to accomplish replication of attribute-value pairs

b: to ensure their consistent placement in the appropriate home node

c: to recover from node or link failures

Ans: ___________ (a/b/c/all)

ANSWERS

1>T

2>T

3>T

4>T

5>broadcast

6>Unit Distance Graph

7>T

8>more

9>T

10>MAC

11>all

12>all

13>S-MAC

14>all

15>periodic listen & sleep

16>Distributed Coordinate Function

17>collision avoidance

18>IEEE 802.15.4

19>ZigBee

20>all

21>S-MAC, 802.15.4

22>both


16

23>LS

24>DV

25>both

26>Dynamic Source Routing

27>Adhoc On-demand Distance Vector Routing

28>both

29>T

30>all

31>pull, push

32>T

33>smaller

34>topology control

35>greedy distance

36>compass

37>greedy distance

38>both

39>convex

40>Other Face Routing

41>OFR

42>Other Adoptive Face Routing

43>both

44>spanner, stretch factor

45>both

46>Relative Neighborhood Graph

47>RNG

48>Gabriel

49>Gabriel, RNG

50>both

51>Restricted Delaunay Graph

52>Localized Delaunay Triangulation

53>greedy distance, perimeter

54>Greedy Perimeter Stateless Routing

55>both

56>greedy distance, perimeter

57>Trajectory Based Forwarding

58>TBF

59>rumor

60>both

61>more

62>O(1/ ra)

63>minimum energy broadcast

64>Minimum Spanning Tree

65>wireless multicast advantage

66>NP

67>6,12

68>T

69>Broadcast Incremental Power

70>Prim

71>Geographical & Energy Aware Routing

72>GEAR

73>both

74>delivery

75>Learning Real Time A

76>50,100,50,25,45

77>both

78>recursive geographic forwarding

79>restricted flooding


17

80>restricted flooding

81>sink, source, interest

82>interval

83>duration

84>sink

85>gradient

86>sink

87>pull, push

88>T

89>data

90>reactive

91>T

92>rumor

93>rumor

94>ACQUIRE

95>ACQUIRE

96>ACQUIRE

97>Information Driven Sensor Querying

98>Geographic Hash Table

99>T

100>GPSR

101>T

102>less

103>T

104>T

105>T

106>data, node

107>all


18

CHAPTER 4: INFRASTRUCTURE ESTABLISHMENT

1>The problem of__________ for a sensor network is how to set the radio range for each node so

as to minimize energy usage, while still ensuring that the communication graph of the nodes

remains connected and satisfies other desirable communication properties (topology control/traffic

monitoring)

2>CTR stands for__________

3>__________problem states "compute the minimum common transmitting range r such that the

network is connected" (topology control/critical transmitting range)

4>The probabilistic theory best suited to the analysis of CTR is the theory of __________

(GRG/GLS)

5>GRG stands for__________

6>In__________ setting, n points are distributed into a region according to some distribution, and

then some aspect of the node placement is investigated (GRG/GLS)

7>If n points are randomly and uniformly distributed in the unit square, then the critical

transmission range is, with high probability

a: r=c.sqrt (n/logn)

b: r=c.sqrt (logn/n)

Ans: ___________ (a/b/either)

8>One should choose_____ ranges in areas of high node density and ______ranges in regions of

low density (short/long)

9>The range assignment problem has been shown to be NP complete for dimensions __& above

(1/2)_________

10>___________MST based algorithms can be expensive to implement on typical sensor nodes

(homogeneous/non-homogeneous/either)

11>Give example of protocol that can be used to directly solve the CTR problem in a distributed

way: ___________ (COMPOW/COMPASS)

12>__________protocol computer routing tables of each node at different power levels and a node

selects the minimum transmit power so that its routing table contains all other nodes

(COMPOW/COMPASS)

13>___________allows hierarchical structures to be built on the nodes and enables more efficient

use of scarce resources such as frequency spectrum, bandwidth and power (clustering/classification)

14>___________allows the same time or frequency division multiplexing to be reused across non-

overlapping clusters (clustering/classification)

15>The more capable nodes can naturally play the role of __________ (cluster leader/cluster head)

16>__________are nodes that aid in passing traffic from one cluster to another (gradient/gateway)

17>___________can be used to thin out parts of the network where an excessive number of nodes

may be present (classification/clustering)

18>Since the nodes in a sensor network operate independently , their clocks may not be or stay,

synchronized with one another (true/false) ___________

19>For time synchronization, the wired protocols assume the existence of highly accurate master

clocks on some network nodes such as ___________ (skew clock/atomic clock)

20>In wireless sensor network

a: no special master clocks are available

b: connections are ephemeral

c: communication delays are inconsistent and unpredictable

Ans: ___________ (a/b/c/all)

21>Computer clocks are based on ___________oscillators which provide a local time for each

sensor network node (software/hardware)

22>For a perfect hardware clock, the derivative dC (t)/dt should be___ to 1 (=/</>)

23>wrt clocks and communication delays, a typical value of p for today's hardware clock is 10-__

(3/6/9)


19

24>___________can actually change over time due to environmental conditions such as

temperature and humidity (clock atomic/clock skew)

25>Time difference caused by the lack of a common time origin are referred to as___________

(clock phase difference/clock bias)

26>The latency in channel can be decomposed into following components

a: send time

b: access time

c: propagation time

d: receive time

Ans: ___________ (a/b/c/d/all)


Send time: this is the delay incurred while waiting for access to the transmission channel due to

contention, collisions etc

Access time: this is the time for message to travel across the channel to the destination node

Propagation time: this is the time for the network interface on the receiver side to get the message

and notify the host of its arrival

Receive time: this is the time taken by the sender to construct the message ___________

28>___________delay can be kept small by time stamping the incoming packet initiate the network

driver's interrupt handler (receive time/send time/propagation time/access time)

29>Time synchronization can be propagated across the network by using a ___________tree

favoring direct connections with reliable delays (binary/spanning)

30>In many situations involving temporal reasoning, the temporal ordering of events matters

______than the exact times when events occurred (less/more)_____

31>___________methods provide a lightweight protocol that can be used to move clock readings

around the network and perform temporal comparisons (interval/reference)

32>Time comparisons are not sufficient for all applications and mappings from event times to time

intervals may quickly become useless if ___________increase the interval sizes beyond reasonable

limits (long delay/multi-hop route/either)

33>RBS stands for___________

34>The key idea of the ___________is to use the broadcast nature of the wireless communication

medium to reduce delays and delay uncertainty in the synchronization protocol (interval

method/RBS)

35>___________refers to the maximum offset between any pair of receiver nodes (group

interval/group dispersion)

36>One way to estimate ___________among pairs of receivers is to do a least-squares linear

regression among all the pair-wise measurements obtained for the two receivers in a sequence of

reference broadcasts (clock skew/phase difference)

37>___________is a method that allow the nodes in a network to determine their geographic

positions on their own as much as possible, during the network initialization process (self

tracking/self localization)

38>___________is a method that allows other nodes to obtain the location of a desired node, after

the initial phase in which each node discovers its own location (tracking service/location service)

39>The nodes that know their positions are called___________ (locatable/landmark)

40>Drawbacks of GPS

a: GPS receivers can be expensive and difficult to incorporate into every sensor node for a number

of practical reasons including cost, power consumption, large form factors

b: GPS systems do not work indoor or under ford foliage or in other expectable conditions

Ans: ___________ (a/b/both)

41>___________methods aim at estimating the distance of a receiver to a transmitter , by

exploiting known signal propagation characteristics (interval/ranging)

42>RSS stands for___________

43>___________technique can be used to estimate the RF signal strength at the receiver

(RSS/RBS)

44>in general, localization to within a few meters is the best that can currently be attained

with___________ methods (RSS/RBS)


20

45>A way to estimate distance is to measure the time it takes for a signal to travel from sender to

receiver, this can be multiplied by the signal propagation speed to yield distance. Such methods are

called___________ technique (TDOA/TOA)

46>Since the exact time of transmission may be hard to know, a way to estimate distance is to

measure the ___________at two receivers, which then lets us estimate the difference in distances

between the two receivers and the sender (TDOA/TOA)

47>Local pairs of beacons can be used to estimate local propagation speed (true/false)___________

48>___________is similar to the collaborative source localization (atomic multi-lateration/attribute

based routing)

49>Collaborative multi-lateration proceeds by computing substructures of the network

called___________ (spanning tree/collaborative sub-tree)

50>___________are sub-graphs of the full network graph in which there are enough constraints to

make the localization problem sufficiently overdetermined that error accumulation is avoided

(spanning tree/collaborative subtree)

51>Collaborative subtrees are built using the notion of ___________nodes (tentatively

unique/temporally unique)

52>A node is called___________ during a multilateration sequence if its position can be uniquely

determined , assuming the positions of the other nodes used as references are unique (tentatively

unique/temporally unique)

53>___________algorithm is used to traverse the network from a given node and accumulate

nodes that can form a collaborative subtree (regression/recursive)

54>APIT stands for___________

55>___________test can be used for range-free localization (APIT/ADIT)

56>For any triplet of landmarks that a node can hear, if the node passes the___________ test with

respect to these landmarks , then the node is declared to be in the triangle defined by the landmarks

(APIT/ADIT)

57>APIT failures happen less than___% of the time (14/15/16)________

58>___________is a mechanism for mapping from node IDs of some sort to node locations

(tracking service/location service)

59>The Grid system uses a distributed location service termed___________ (GLS/GRG)

60>The key idea of___________ is to distribute the load so that each network node acts as a

location server for a relatively small number of other nodes, most in its neighborhood (GLS/GRG)

61>___________provides a mapping from node IDs to node locations (GLS/GRG)

62>In GLS, if we have n nodes that are reasonably uniformly distributed in a field , then the depth

of the quad-tree will be___________{O (logn) or O (logn+1)}

63>Nodes can be aggregated into clusters

a: to better share resources, control redundancy

b: to enable hierarchical tasking and control

Ans: ___________ (a/b/both)

64>___________remain especially challenging problems in the adhoc deployment setting

(synchronization/localization/both)

65>In location dependent systems such as the___________ indoor system, beacons in each room

broadcast location information to listener nodes (cricket/hockey)

ANSWERS

1>topology control

2>Critical Transmitting Range

3>CTR

4>GRG

5>Geometric Random Graph

6>GRG

7>b

8>short, long

9>2

10>ether

11>COMPOW

12>COMPOW


21

13>clustering

14>clustering

15>cluster head

16>gateway

17>clustering

18>T

19>atomic clock

20>all

21>hardware

22>equal

23>6

24>clock skew

25>either

26>all

27>1-d 2-a 3-b 4-c

28>receive time

29>spanning

30>more

31>interval

32>either

33>Reference Broadcast System

34>RBS

35>group dispersion

36>both

37>self-localization

38>location service

39>landmark

40>both

41>ranging

42>Received Signal Strength

43>RSS

44>RSS

45>TOA

46>TDOA

47>T

48>atomic multi=lateration

49>collaborative subtree

50>collaborative subtree

51>tentatively unique

52>tentatively unique

53>recursive

54>Approximate Point In Triangle

55>APIT

56>APIT

57>14

58>location service

59>GLS

60>GLS

61>GLS

62>O(log n)

63>both

64>both

65>cricket


22

CHAPTER 5: SENSOR TASKING AND CONTROL

1>_____sensor can be tasked to look for animals of a particular size and color. _____sensor can be

tasked to detect the presence of a particular type of vehicle (acoustic/camera)

2>IDSQ stands for__________

3>The purpose of a sensor system is to obtain information that is as extensive and detailed as

possible about the unknown parts of the world state (true/false)__________

4>When we know the relevant manifest variables defining the world state, then computing the

answers to queries about the world state is a__________ problem (standard algorithm design/range

assignment)

5>The standard algorithm design problem needs to be modified in the sensor network context

because

a: the values of the relevant manifest variables are not known but have to be sensed

b: the cost of sensing different variables or relations of the same type can be vastly different

c: frequently the value of a variable or a relationship between variables, may be impossible to

determine using the resources available in the sensor network

ns: __________ (a/b/c/all)

6>The online nature of sensing requires the use of methods such as___________ to account for the

fact that the value of sensor readings cannot be known before they are made (competitive

analysis/value of information/either)

7>The main idea of information based sensor tasking is to base sensor selection decisions on

information content as well as constraints on resource consumption, latency and other costs

(true/false)___________

8>___________formulates the sensor tasking problem as a general distributed constrained

optimization that maximizes information gain of sensors while minimizing communication and

resource usage (IDSQ/IBST)

9>___________refers to the knowledge about the target state such as position and velocity (belief

state/true state)

10>Following approaches can be used for localizing a stationary source and tracking a moving

source

a: a leader node might act as a relay station to the user, in which case the belief resides at this node

for an extended time interval, and all information has to travel to this leader

b: the belief itself travels through the network, and nodes are dynamically assigned as leaders

Ans: ___________ (a/b/both)

11>Using___________ criterion, the leader node at the center always selects the nearest node

among those whose measurements have not been incorporated (NP/NN)

12>__________based selection favors sensors along the longer axis of the covariance fit of residual

uncertainty in localization (mutual information/Mahalanobis)

13>In __________sensor network systems, we must balance the information contribution of

individual sensors against the cost of communicating with them (centralized/distributed)_

14>For multimodal, non-Gaussian distributions, ___________measure provides a better

characterization of the usefulness of sensor data (mutual information/Mahalanobis)

15>___________can be interpreted as the Kullback Leibler divergence between the belief after and

before applying the new measurement (mutual information/Mahalanobis)

16>The appropriateness of a particular utility measure for a sensor selection problem depends on

following factors

a: the characteristics of the problem such as the data and noise models

b: the computational complexity of computing the measure

Ans: __________ (a/b/both)

17>_____measure is easy to compute, although limited to certain data models.______applies to

multimodal distributions, but its computation requires expensive convolution of discrete points if one

uses a grid approximation of probability density functions (mutual information/Mahalanobis)


23

18>___________method is based on the cluster leader type of distributed processing protocol

(IDSQ/IBST)

19>In IDSQ algorithm, arrange following steps in correct order

a: follower nodes

b: initial sensor reading

c: initialization

d: sensor selection

e: belief quality

Ans: ___________ (cbaed/cabde/cabed)

20>In the___________ based protocol , it is necessary to design efficient and robust algorithms for

electing a leader, since typically more than one sensor may have detections about a target

simultaneously (planar/leader)

21>In leader election protocol, arrange the following steps in correct order

a: if there are one or more messages with an earlier time stamp, the node knows that it is not the

leader

b: if none of the messages contains earlier time stamps, but some message contains a time stamp

identical to the node's detection time, the node compares the likelihood ratio.If the node's likelihood

ratio is higher, the node becomes the leader

c: if none of the messages is time stamped earlier than the node's own detection, the node declares

itself leader

Ans: ________ (bca/cba/cab)

22>In the leader based protocol, following different criteria can be used for choosing the next sensor

a: nearest neighbor

b: mahalanobis distance

c: maximum likelihood

d: best feasible region

Ans: ___________ (a/b/c/d/all)

23>PIR stands for___________

24>NN stands for___________

25>A primary purpose of sensing in a sensor network is to collect and aggregate information about

a phenomenon of interest (true/false)___________

26>___________provides us with a method of selecting the optimal order of sensors to obtain

maximum incremental information gain (IDSQ/IBST)

27>A user issues a query from an arbitrary node, which is called as___________ node, requesting

the sensor network to collect information about a phenomenon of interest (query proxy/query

processing)

28>Using the___________ measure, the querying node can determine which node can provide the

most useful information while balancing the communication cost, w/o the need to obtain the remote

sensor data first (mahalanobis distance/mutual information)

29>In a ___________belief carrier protocol, the belief is successively handed off to sensor nodes

closest to locations where useful sensor data are being generated (static/dynamic)

30>In___________ belief carrier protocol, the current sensor node updates the belief with its

measurement and sends the estimation to the next neighbor that it determines can best improve the

estimation (static/dynamic)

31>The___________ algorithm fails due to its lack of knowledge beyond the immediate

neighborhood (greedy/recursive)

32>Example of local routing algorithm is___________ (GPSR/GPRS)

33>In general, the information contribution of each sensor is state-dependent

(true/false)___________

34>Following are examples of standard shortest path algorithms on graphs___________

(dijkstra/bellman ford/both)

35>MSE stands for___________

36>The error in localization, measured as mean squared error , generally ___________as more

sensor measurements are incorporated (increases/decreases)

37>State dependency is an important property of sensor data aggregation, regardless of specific

choices of information metrics (true/false)___________

38>Search cost function is defined as the path cost___________ the information gain (plus/minus)


24

39>To mitigate the combinational explosion problem, following strategies can be used

a: we can restrict the search for optimal paths to a small region of the sensor network

b: we can apply heuristics to approximate the costs so that they can be treated as additive

Ans: ___________ (a/b/either)

40>In sensor network, the goal is to route a query from the query proxy to the exit point and

accumulate as much information as possible along the way, so that one can extract a good estimate

about the target state at the exit node and yet keep the total communication cost close to some

prespecified amount (true/false)___________

41>When it is possible to estimate the cost to go, the A* ___________method can be used (best

first search/heuristic search)

42>The basic A* is a ___________search, where the merit of a node is assessed as the sum of the

actual cost g paid to reach it from the query proxy , and the estimated cost h to pay to get to the

exit node (depth first/best first)

43>For real-time path-finding, we use a variation of the A* method called ___________search

(RTA/BFS)

44>RTA stands for___________

45>In many applications, the physical phenomenon may be mobile, requiring the network to

migrate the information according to the motion of the physical phenomenon for

communication___________ reasons (efficiency/scalability/both)

46>In practical applications, the effect of a physical phenomena usually attenuates with distance,

thus limiting the propagation of physical signals to geographical regions around the physical

phenomenon (true/false)___________

47>The physical phenomenon being sensed change over time (true/false)___________

48>Geographically based group initiation and management have to be achieved by a___________

protocol distributed on all sensor nodes (greedy/lightweight)

49>Considering that the group membership is dynamic as the targets move and that the network is

formed in an adhoc way such that no nodes have the knowledge of the global network topology.

These difficulties may be tackled via following techniques

a: leader based tracking algorithm where at any time each group has a unique leader who knows the

geographical region of the collaboration

b: recent advances in geographical routing that do not require the leader to know the exact

members of its group

Ans: ___________ (a/b/both)

50>The information based approach to sensor querying and data routing selective invokes sensors

to___________ the number sensing actions needed for a given accuracy and hence latency &

energy usage (minimize/maximize)

51>___________is a set of sensor nodes responsible for the creation and maintenance of a target's

belief state over time, which we call track (co-operative group/collaborative group)

52>is a set of sensor nodes responsible for the creation and maintenance of a target's belief state

over time, which we call ___________ (trunk/track)

53>How the leader node maintains and migrates the collaborative processing group. Arrange the

following steps in correct order

a: sensors are selected to acquire new measurements using the sensor selection algorithm

b: after the leader is elected, it initializes a belief state as uniform disk centered at its own location_

c: as the target moves, the sensors that did not previously detect may begin detecting

Ans: __________ (cba/acb/bca)

54>Following are examples of data association algorithms

a: optimal assignment

b: multiple hypothesis processing

Ans: ___________ (a/b/both)

55>Using ___________algorithm , the ambiguities in the target identities after crossing tracks can

be resolved using additional local evidence of the track identity and then propagate the information

to other relevant tracks (identity management/data association)

56>We can convert global estimation and tracking problem into a local analysis using the so

called___________ (primal dual transformation/parametric approximation)

57>A wireless sensor network is severely constrained by the on-board battery power

(true/false)___________


25

58>If a sensor only wakes up, senses and communicates when it expects an event of interest, the

power consumption of the network could be dramatically reduced (true/false)___________

59>The idea of information driven sensor tasking, and its realization in IDSQ, is to base the sensor

selection the potential contribution of a sensor to the current estimation task while using a moderate

amount of resources (true/false)___________

60>Following protocol can be used for sensing stationary or moving physical phenomena

a: leader based

b: moving center of aggregation

Ans: ___________ (a/b/both)

61>In the resource limited sensor networks, the appropriate balance between the information and

the costs is of paramount concern, since unnecessary data collection or communication consumes

precious bandwidth and energy and overload human attention (true/false)___________

62>Primary function of a senor network is to collect information from a physical environment

(true/false)___________

63>Routing an a sensor network must be co-optimized with the information aggregation or

dissemination (true/false)___________

64>___________group is an important abstraction of physical sensors, since individual sensors are

ephemeral and hence less important, and sensors collectively support a set of tasks (co-operative

processing/collaborative processing)

65>A major benefit of establishing the collaborative group abstraction is in enabling the

programming of sensor networks to move from addressing individuals nodes to addressing

collectives (true/false) ___________

ANSWERS

1>camera

2>Information Driven Sensor Querying

3>T

4>standard algorithm design

5>all

6>either

7>T

8>IDSQ

9>belief

10>both

11>NN

12>Mahalanobis

13>distributed

14>mutual information

15>mutual information

16>both

17>Mahalanobis , mutual information

18>IDSQ

19>cabed

20>leader

21>cab

22>all

23>Passive Infrared

24>nearest-neighborhood

25>T

26>IDSQ

27>query proxy node

28>Mahalanobis

29>dynamic

30>dynamic

31>greedy

32>GPSR

33>T


26

34>both

35>Mean Squared Error

36>decreases

37>T

38>minus

39>either

40>T

41>heuristic search

42>best first

43>RTA

44>Real Time A*

45>both

46>T

47>T

48>lightweight

49>both

50>minimize

51>collaborative group

52>track

53>bca

54>both

55>identity management

56>spinal-dual transformation

57>T

58>T

59>T

60>both

61>T

62>T

63>T

64>collaborative processing

65>T


27

CHAPTER 6: SENSOR NETWORK DATABASES

1>From a data storage point of view ,one may think of a sensor network as a distributed database

that

a; collects physical measurements about the environment

b; indexes them

c; serves queries from users and other applications external to or from within the network

Ans; __________ (a/b/c/all)

2>The advantage of the database approach is that it provides a separation between the logical view

of the data held by the sensor network and the actual implementation of these operations on the

physical network (true/false)__________

3>In a classical DBMS ,data is stored in a__________ location (centralized/distributed)

4>The structure and constraints of the data format are called database__________ (table/schema)

5>The database scheme are typically defined or modified by a database administrator using

__________ (DML/DDL)

6>DDL stands for___________

7>Today most databases employ relational schemas and their variants, organizing data into tables

whose_____ are record tuples and whose______ are labeled by data attributes rows/columns)

8>___________compiler translates the definitions into metadata which is stored in permanent

storage along with the actual data (DML/DDL)

9>___________is a data structure describing the structure of the database data and the constraints

they must satisfy (metadata/temporal data)

10>In a typical database system ,the___________ directly controls storage devices such as disks

and the flow of data between them and main memory (storage & buffer manager/transaction

manager )

11>The database is updated through units of work named___________ (transition/transaction)

12>It is the job of the__________ to guarantee that transactions are executed atomically and in

apparent isolation from other transactions (storage & buffer manager/transaction manager)

13>A user queries the database in a high level logical query language such as___________

(Oracle/SQL)

14>A query is parsed by the_____ and translated into an optimized execution plan ,which is then

processed by the______ to answer the user query (execution engine/query processor)

15>In any database system, there are trade offs between the speed of answering queries and the

speed of performing database updates (true/false)___________

16>In__________ database systems ,data storage may be allocated among several geographical

separated locations ,connected by a communications network (centralized/distributed)

17>___________database makes the job of the query processor significantly harder


18>Most query execution plans can be represented as trees where the_____ represent database

operators and the______ correspond to producer-consumer relationships among operators


19>P2P Stands for___________

20>In___________ networks ,active processors can number in the tens to hundreds of thousands

and may come on the network and go off the network at arbitrary times (P2P/PPP)

21>Another recent trend in database systems is to consider systems for data streams. Such systems

are aimed at handling long running___________ queries such as may arise in network or traffic

monitoring ,telecom call ,stock market transaction or web log record summarization

(continuous/discontinuous)

22>Each sensor in a sensor network takes___________ measurements of physical phenomena such

as heat, sound, light ,pressure or motion (time sequenced/time stamped)

23>The issue of where to store the data becomes of paramount importance since_____

dominates______ (energy landscape/communication cost)


28

24>Following approaches can be used for implementing databases to support sensor network

a; transfer all the data to one or a small number of external warehouses ,where traditional DBMS

system could be deployed

b; store the data within the network itself and allow queries to be injected anywhere in the network

Ans; ___________ (a/b/both)

25>At the physical level, there are following major distinguishing characteristics of sensor networks

when it comes to database implementation

a; the network replaces the storage and buffer manager--data transfers are from data held in node

memory as opposed to data blocks on disk

b; node memory is limited by cost and energy considerations

Ans; ___________ (a/b/both)

26>Following are challenges in sensor network databases

a; the system as a whole is highly volatile

b; relational tables are not static since new data is continuously being sensed

c; the high energy cost of communication encourages in-networking processing during query

execution

d; access to data may be hampered by arbitrarily long delays and the rates at which input data

arrives to a database operator can be highly variable

Ans; ___________ (a/b/c/d/all)

27>Following are challenges in sensor network databases

a; limited storage on nodes and high communication costs imply that older data has to be discarded

b; sensor tasking interacts in numerous ways with the sensor database system

c; classical metrics of database system performance ,such as throughput or delay may have to be

adjusted in the sensor network context because of high variance in these quantities

Ans; ___________ (a/b/c/all)

28>Following are differences between sensor network data and those of other databases at the

logical level

a; sensor network data consists of measurements from the physical world

b; additional operators have to be added to the query language to specify durations and sampling

rates for the data to be acquired

c; while single shot queries are possible and useful in sensor networks ,we expect that a good

fraction of the queries will be of the continuous ,long running type such as monitoring the average

temperature in a room

d; it is important to have operators for correlating sensor readings and comparing them with past

statistics

Ans; ___________ (a/b/c/d/all)

29>Sensor network differs from__________ networks in that nodes operate with limited energy

,processing and memory resources (data streams/P2P)

30>Sensor network differs from ___________networks in that geographic location can be of great

importance in deciding what information to store and what information to query for (data

streams/P2P)

31>It is advantageous to express queries to a sensor network database at a logical, declarative level

,using relational languages such as SQL (rue/false)___________

32>In querying the physical environment ,___________level interfaces allow nonexpert users to

easily interact with the database (low/high)

33>_____clause specifies the period during which data is to be collected, and the______ clause

specifies the frequency at which the query results are returned (sampling period/duration)

34>There may be____ queries such as the report results over an extended time window ,___queries

concerning the data in the network at a given point in time and____ queries that ask for aggregate

information over historical data (snapshot/historical/continuous)

35>The queries on sensor networks may

a; aggregate data over a group of sensors or a time window

b; contain conditions restricting the set of sensors from contributing data

c; correlate data from different sensors

d; trigger data collection or signal processing on sensor nodes

e; spawn subqueries as necessary

Ans; ___________ (a/b/c/d/e/all)


29

36>Not all users of a database system will be human operators (T/F)___. Programs running on the

nodes themselves may generate queries in order to decide what sensing actions a node should take

(T/F)___

37>___________sensor network database system maintains an SQL-type query interface for users

at a front end server connected to a sensor network (courage/cougar)

38>Distributed query execution is optimized for___________ (resource usage/reaction time/both)

39>Cougar represents each type of sensor in a network as an___________ ,as in most modern

object-relational databases (ASN/ADT)

40>In Cougar database ,___________provides controlled access to encapsulated data through a

well defined set of access functions (ASN/ADT)

41>An ADT object in the Cougar database corresponds to a___________ sensor in the real world

(logical/physical)

42>STFT stands for___________

43>The public interface of a seismic sensor ADT can comprise signal processing functions such as

a; STFT

b; vibration signature analysis

Ans; ___________ (a/b/both)

44>___________relations are relations that are not actually materialized as ordinary table

(base/virtual)

45>Cougar introduces_____ relations in contrast to the______ relations defined in the database

schema (base/virtual )

46>Cougar considers___________ query processing in the network (centralized/distributed)

47>Sensor data invariably contains measurement uncertainty due to ___________ (device

noise/environmental perturbation/either)

48>GADT stands for___________

49>___________models the uncertainty as a continuous probability distribution function over

possible measurement values (ADT/GADT)

50>An operation named___________ primitive allow for probabilistic equality tests ,so one can

meaningfully compare different Gaussian variables (Prob/Conf/Diff)

51>Range queries are another important class of sensor network queries (true/false)___________

52>In the___________ warehousing approach ,each sensor forwards its data to a central server or

warehouse connected to the network via an access point (centralized/decentralized)

53>Following are disadvantages of centralized warehousing

a; the nodes near the distinct point become traffic hot spots and central points of failure plus they

may be depleted of energy prematurely

b; this approach does not take advantage of in-network aggregation of data to reduce the

communication load when only aggregate data needs to be reported

c; sampling rates have to be set to be the highest that might be needed for any potential query

,possibly further burdening the network with unnecessary traffic

d; customers of the data may be other applications running on nodes themselves in the network

Ans; ___________ (a/b/c/d/all)

54>In___________ approach, the data is stored within the network (centralized warehouse/in-

network storage)

55>At the center of the___________ design is the appropriate choice of storage points for the data

,which act as rendezvous points between data and queries ,so that the overhead to store and access

the data is minimized and the overall load is balanced across the network (centralized warehouse/in-

network storage)

56>Features of the in-network storage

a; allows data to be aggregated before it is sent to an external query

b; takes advantage of locality of information for in-network queries

c; load-balances the database costs across the nodes

Ans; ___________ (a/b/c/all)

57>Following metrics can be used for general database systems

a; network usage b; preprocessing time

c; storage space requirement d; query time

e; throughput f; update & maintenance cost

Ans; ___________ (a/b/c/d/e/f/all)


30


network usage; the time taken to construct an index

preprocessing time; the storage for the data and index

storage space requirement; the time taken to process a query ,assemble an answer ,and return this

answer

query time; the average number of queries processed per unit of time

throughput; costs such as processing sensor data ,insertions ,dejections or repairs when nodes fail

update & maintenance cost; it is characterized by total usage and hot spot usage

59>Network usage is characterized by______ which refers to the total number of packets sent in

the network and_____ which refers to the maximal number of packets processed by any particular

node (hot spot usage/total usage)

60>A sensor network database differs from a traditional centralized system in that

a ; resources are severely constrained

b; query processing is tightly coupled with networking and application semantics

Ans; ___________ (a/b/both)

61>When designing a sensor database, we desire he following properties

a; persistence

b; consistency

c; controlled access to data

d; scalability in network size

e; load balancing

f; topological generality

Ans; ___________ (a/b/c/d/e/f/all)


Persistence; the database architecture should work well on a broad range of network topologies

Consistency; as the number of nodes increases ,the system's total storage capacity should increase

Controlled access to data; a query must be routed correctly to a node where the data are currently

stored

Scalability in network size; data stored in the system must remain available to queries, despite

sensor node failures and changes in the network topology

Load balancing; different update operations must not undo one another's work ,and queries must

always see a valid state of the database

Topological generality; storage should not unduly burden any one node nor should any node become

a concentration point of communication

63>In-network query processing can be used to provide substantial energy savings when serving

aggregate queries. This saving is possible because

a; separating data at intermediate nodes reduces the overall number of messages the network has

to transmit ,thus reducing communication and prolonging the lifetime of the network

b; combining data at intermediate nodes reduces the overall number of messages the network has

to transmit ,thus reducing communication and prolonging the lifetime of the network

Ans; ___________ (a/b/both)

64>In the___________ based approach ,the aggregation occurs at an external server ,each sensor

sends its data directly to the server (client/server)

65>In-network aggregation and query processing typically involve___________ (query

propagation/data aggregation/both)

66>A key challenge for in-network aggregation is the design of an optimal data aggregation

schedule that is___________ efficient (energy/time/both)

67>___________provides an SQL-style declarative query interface, and implement aggregation

mechanisms that are sensitive to resource constraints and loopy communication (TinyOS/TinyOS)

68>TinyDB supports following SQL operators

a; count

b; min

c; max

d; sum

e; average

Ans; ___________ (a/b/c/d/e/all)

69>TinyDB supports following extensions___________ (median/histogram/both)


31

70>For______ operator, it can be shown that the size of the partial state record is proportional to

the size of the data set it summarizes ,while in_____ operator ,the size correlates with statistical

properties (median/histogram)

71>___________are distributive ,meaning the size of an intermediate state is the same as that of

the final aggregate__________ is algebraic in that the partial state records are not themselves

aggregates for the data set ,but are of constant size (max/min/count/average/sum)

72>_____is holistic and______ is content sensitive (median/histogram)

73>The performance of TinyDB is___________ related to the amount of intermediate state

information required per aggregate (directly/inversely)

74>TinyDB uses ___________ based mechanism for data aggregation (emoge/epoch)

75>TinyDB builds a___________ tree for aggregation (static/dynamic)

76>In the query tree ,_____are the operators and______ are data dependencies among the

operators (nodes/edges)

77>The task assignment problem is___________ complete (NP/PN)

78>A tree based query propagation mechanism is appropriate for a ___________based application

(client/server)

79>DCS stands for___________

80>____________is a method proposed to support queries from any node in the network by

providing a rendezvous mechanism for data and queries that avoids flooding the entire network

(DCE/DCS)

81>Directed diffusion is an example of data centric routing (true/false)___________

82>At the center of a DCS system are___________ points ,where data and queries meet

(rendezvous/meeting)

83>GHT stands for___________

84>An instance of DCS is the ___________ (GLS/GHT)

85>in___________ ,the translation from node attributes to storage location is accomplished by a

hash function ,which attempts to distribute data evenly across the network (GLS/GHT)

86>___________may be regarded as a variant of publish and subscribe except the event broker

serves as the data storage and rendezvous point (DCS/DCE)

87>A type of query that is especially appropriate for sensor network databases is a

__________query (range/boundary)

88>In___________ query ,a certain range is specified for a number of attributes of interest on the

data sought (range/boundary)

89>In general ,sensor network data is multi-attribute (true/false)___________

90>__________is aimed at point queries or exact matches, so it is not well suited for queries

involving data ranges (GLS/GHT)_

91>in general ,the complexity of answering a query in a sensor network will be a function of

a; the size of the data in the network

b; the number of records returned

Ans; ___________ (a/b/both)

92>Following are classical measures of the quality of an index___________ (speed/size/both)

93>The ___________data the index stores ,the faster the query processing can be (less/more)

94>wrt one dimensional indices ,the particular subsets of data forming the prestored answers are

referred to as the___________ subsets (orthogonal range/canonical)

95>In canonical subsets of sensors along a road ,an___________ node in the tree aggregates

information from all its descendant sensors in th tree (internal/external)

96>Partial data aggregation is a key feature of any indexing scheme for range searching

(true/false)___________

97>When we have a set of attributes each parameterized by a scalar value and query with a interval

along a subset of the parameters ,then we call this as___________ searching (orthogonal

range/canonical)

98>Examples of hashing/partitioning schemes are___________ (grid files/partitioned hashing/both)

99>Examples of tree based index structure include

a; multilevel indices b; k-d trees

c; quad tree d; R trees

Ans; ___________ (a/b/c/d/all)

100>The storage cost for storing m events into ___________is O (m) {k-d tree/multi level}


32

101>Range searching indices provide a hierarchical summarization of records or events in the

database according to simple attributes of interest (true/false)__________

102>Wavelet transforms provide one way to compress and summarize information for both temporal

and spatial signals ,and are widely used in__________ processing (signal/image/both)

103>__________is a system that provides multi-resolution storage and search for sensor data

(DIAMETERS/DIMENSIONS)

104>DIFS stands for__________

105>If we can partition aggregated data in a meaningful way, then we can distribute that data over

several nodes in the network and thus lessen the load on nodes near the hierarchy root. A system

that has developed this approach is__________ (DIPS/DIFS)

106>__________uses a modified GHT to find an index node (DIPS/DIFS)

107>The idea of storing information locally is at the heart of the__________ approach to storing

data in a sensor network (fractional cascading/locality preserving hashing)

108>The key idea of the_________ approach is to store at each sensor information about data

available elsewhere in the network ,but in such a way that a sensor knows only a fraction of the

information from distant parts of the network (fractional cascading/locality preserving hashing)

109>Fractional cascading accomplishes following goals simultaneously

a; the total amount of information duplication across all sensors is kept small because of the

geometric decrease with distance

b; the communication costs required to build this index and its update cost remain reasonable ,as on

a the average information travels only short distances

c; neighboring sensors have highly correlated world views ,this allows for smooth information

gradients and enables local search algorithms to work well

Ans; __________ (a/b/c/all)

110>DIM stands for__________

111>__________approach is developed in the DIM system (fractional cascading/locality preserving

hashing)

112>In__________ approach ,we map the attribute space to the plane so that nearby locations in

attribute space correspond to nearby locations in the plane (fractional cascading/locality preserving

hashing)

113>The key idea of __________is a clever construction of a locality preserving mapping between

the multidimensional attribute space and the spatial domain of sensors (DIM/DIFS)

114>_____databases has to store static information while_____ databases must deal with

continuous data acquisition and allow the temporal aspects of the data to be used in queries

(traditional/sensor network)

115>The sensor data acquired by a single node over time can be processed and summarized directly

on that node ,with no additional communication costs (true/false)___________

116>One of disadvantage of sensor network is that overall node storage is very limited


117>The__________ system computes multi-resolution summaries of data

(DIAMETERS/DIMENMSIONS)

118>__________is a monotonically decreasing function specifying acceptable query response

accuracy as a function of data age (mining function/aging function)

119>KDS stands fo___________120>wrt indexing motion data, in __________setting ,the

correctness of the index is certified by certain atomic predicates called certificates ,on the

parameters defining the index (KDC/KDS)

121>__________approach incrementally tracks the index structure as objects move and can be

used to answer queries about the current state of the world (KDC/KDS)

122>Following are general approaches to indexing motion data

a; using time oblivious approach

b; using KDS approach

Ans; __________ (a/b/both)

ANSWERS

1>all

2>T

3>centralized


33

4>schema

5>DDL

6>Data Definition Language

7>row, column

8>DDL

9>metadata

10>storage & buffer manager

11>transaction

12>transaction manager

13>SQL

14>query processor, execution engine

15>T

16>distributed

17>distributed

18>node, edge

19>peer to peer

20>P2P

21>continuous

22>time-stamped

23>communication costs, energy landscape

24>both

25>both

26>all

27>all

28>all

29>data streams

30>P2P

31>T

32>high

33>duration, sampling period

34>continuous, snapshot, historical

35>all

36>T,T

37>cougar

38>both

39>ADT

40>ADT

41>physical

42>Short Time Fourier Transform

43>both

44>virtual

45>virtual, base

46>distributed

47>either

48>Gaussian ADT

49>GADT

50>diff

51>T

52>centralized

53>all

54>in-network storage

55>in-network storage

56>all

57>all

58>1-f 2-a 3-b 4-c 5-d 6-e

59>total usage, hot spot usage

60>both


34

61>all

62>1-d 2-c 3-e 4-b 5-f 6-a

63>both

64>server

65>both

66>both

67>TinyDB

68>all

69>both

70>median, histogram

71>max, min, count & sum; average

72>median, histogram

73>inversely

74>epoch

75>static

76>node, edge

77>NP

78>server

79>Data Centric Storage

80>DCS

81>T

82>rendezvous

83>Geographic Hast Table

84>GHT

85>GHT

86>DCS

87>range

88>range

89>T

90>GHT

91>both

92>both

93>more

94>canonical subsets

95>internal

96>T

97>orthogonal range

98>both

99>all

100>k-d tree

101>T

102>both

103>DIMENSIONS

104>Distributed Index for Features in Sensor network

105>DIFS

106>DIFS

107>fractional cascading

108>fractional cascading

109>all

110>Distributed Index for Multi-dimensional data

111>locally preserving hash functions

112>locally preserving hash functions

113>DIM

114>traditional, sensor network

115>T

116>T

117>DIMENSIONS


35

118>aging function

119>Kinetic Data Structure

120>KDS

121>KDS

122>both


36

CHAPTER 7: SENSOR NETWORK PLATFORMS AND

TOOLS

1>Following are different types of programming for sensor networks

a: those carried out by end users

b: those performed by application developers

Ans: __________ (a/b/both)

2>_____may view a sensor network as a pool of data and interact with the network via queries.On

the other hand, _____must provide users of a sensor network with the capabilities of data

acquisition, processing and storage (end user/application developer)

3>CSIP stands for__________

4>Following are different types of node centric programming interfaces

a: imperative language, nesC

b: dataflow style language, TinyGals

Ans: __________ (a/b/both)

5>Following are examples of node level simulator

a: ns-2

b: TOSSIM

Ans: __________ (a/b/both)

6>___________centric programming gives programmers platform support for thinking in high level

abstraction (node/state)

7>Sensor node hardware can be grouped into following categories

a: augmented general purpose computers

b: dedicated embedded sensor nodes

c: system-on-chip (SoC) nodes

Ans: ___________ (a/b/c/all)


augmented

general

purpose

computers:

smart dust, BWRC picoradio node and PASTA node

dedicated

embedded

sensor nodes:

Berkeley mote family, UCLA Medusa family, Ember nodes and MIT

microAMP

SoC nodes: low power PCs, embedded PCs, custom designed PC and various

PDA___________

9>COTS stands for

10>Compared with dedicated sensor nodes, PC like platforms are___________power hungry

(less/more)

11>Which sensor node hardware has high processing capability



c: SoC nodes

Ans: ___________ (a/b/c)

12>Which platform typically use COTS chip sets with emphasis on small from factor, low power

processing and communication, and simple sensor interfaces



c: SoC nodes

Ans: ___________ (a/b/c)


37

13>Berkeley motes has gained wide popularity in the sensor network research community because

of

a: small form factor

b: open source software development

c: commercial availability

Ans: __________ (a/b/c/all)

14>Figure7.1___________

15>In MICA mote , the main micro-controller named___________ takes care of regular processing

(intel/Atmel ATmega103L)

16>In MICA mote, the ATmega103L MCU has integrated____ kB flash memory and ___kB of data

memory (4/64/512)___

17>The RF communication on MICA motes uses the TR=____chip set operating at ____MHz band

(916/1000/1024)

18>MICA motes implement a____ kbps transmission rate (40/60/80)_______

19>MICA mote has maximum transmission range of about ___________feet in open space

(100/200/300)

20>MICA motes support a ____pin I/O extension connector (50/51/52)_______

21>figure7.3___________

22>Radio transmission bear the maximum power consumption (true/false)___________

23>Stand alone embedded systems do not scale up for the programming of sensor networks for

following reasons

a: sensor networks are large scale distributed systems, where global properties are derivable from

program execution in a massive number of distributed nodes

b: sensor network should be able to respond o multiple concurrent stimuli at the speed of changes

of the physical phenomena of interest

Ans: ___________ (a/b/both)

24>___________implies a conceptual model for programmers, with associated techniques for

problem decomposition for the software designers (design platform/design methodologies)

25>_____supports a______ by providing design time language constructs and restrictions, and run

time execution services (design platform/design methodologies)

26>Most design methodologies for sensor network software are___________ centric, where

programmers think in terms of how a node should behave in the environment (state/node)

27>Following are representative examples of node-level programming tools___________

(TinyOS/TinyGALS)

28>___________aims at supporting sensor network applications on resource constrained hardware

platforms such as the Berkeley motes (TinyOS/TinyGALS)

29>___________is a virtual machine for the Berkeley motes (MICA/mate)

30>Features of TinyOS

a: have no file system

b: supports only static memory allocation: implements a simple task model

d: provides minimal device & networking abstractions

e: takes a language based application development approaches

Ans: ___________ (a/b/c/d/e/all)

31>TinyOS organizes components into layers, the_____ a layer is , the closer it is to the hardware;

the______ a layer is, the closer it is to the application (lower/higher)

32>In TinyOS, tasks are non-preemptive (true/false)___________

33>The execution of an interrupt handler is called___________ (event context/event scheduler)

34>___________is an extension of C to support and reflect the design of TinyOS v1.0 and above

(TinyGALS/nesC)

35>___________provides a set of language constructs and restrictions to implement TinyOS

components and applications (nesC/ns2)

36>Interfaces of a nesC component are classified as___________ interfaces (provides/uses)

37>_____interface is a set of method calls exposed to the upper layers while a______ interface is a

set of method calls hiding the lower layer components (provides/uses)

38>In nesC component, _____call is a method call from a lower layer component to a higher layer

component while a______ call is a method call from a higher layer component to a lower layer

component (command/event)


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39>Following are different types of components in nesC, depending on how they are implemented

___________ (modules/configurations)

40>In nesC component, _____are implemented by application code whereas______ are

implemented by connecting interfaces of existing components (modules/configurations)

41>In nesC component, the implementation part of a ___________is written in C-like code

(modules/configurations)

42>TinyOS does not support dynamic memory allocation (true/false)___________

43>In nesC, code can be classified into following types__________ code

(synchronous/asynchronous)

44>In nesC, ______code is reachable from at least one interrupt handler whereas_____ code is only

reachable from tasks (synchronous/asynchronous)

45>In TinyGALS, a dataflow program has a set of processing units called___________

(actors/directors)

46>___________event driven execution can be viewed as a special case of dataflow models, where

each actor is triggered by every incoming event (synchronous/asynchronous)

47>GALS stands for__________

48>TinyGALS is a language for TinyOS (true/false)___________

49>___________mechanism is a way of building event triggered concurrent execution from thread

unsafe components (GUYS/GALS)

50>One of the key factors that affects component reusability in embedded software is the

component___________ (compatibility/composability)

51>TinyGALS addresses concurrency concerns at the_____ level, rather than at the ______level as

in nesC (component/system)

52>An application in TinyGALS is built from following steps

a: constructing asynchronous actors from synchronous components

b: constructing an application by connecting the asynchronous components though FIFO queues

Ans: ___________ (a/b/both)

53>___________in TinyGALS has a set of input ports, a set of output ports and a set of connected

TinyOS components (actor/director)

54>GUYS stands for___________

55>___________variables are a mechanism for sharing global state, allowing quick access but with

protected modification of the data (TinyGALS/TinyGUYS)

56>In the___________ mechanism, global variables are guarded (TinyGALS/TinyGUYS)

57>In the TinyGUYS, the external variables are accessed within a component by using following

keywords ___________ (PARAM_GET/PARAM_PUT/both)

58>In TinyGALS, the code generator automatically generates all of the necessary code for

a: component links and actor connections

b: application initialization and start of execution

c: communication among actors

d: global variables reads and writes

Ans: ___________ (a/b/c/d/all)

59>___________function is one of the first functions called by the TinyGALS runtime scheduler

before executing the application {init () or app_init ()}

60>A node level simulator has the following components

a: sensor node model

b: communication model

c: physical environment model

d: statistics and visualization

Ans: ___________ (a/b/c/d/all)

61>A node in a simulator acts as a software execution platform, a sensor host as well as a

communication terminal (true/false) ___________

62>A key element of the environment within which a sensor network operates is the physical

phenomenon of interest (true/false)___________

63>Depending on how the time is advanced in the simulation, following are different types of

execution models

a: cycle driven simulation b: discrete event simulation

Ans: ___________ (a/b/both)


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64>_____simulation discretizes the continuous notion of real time into ticks and simulates the

system behavior at these ticks (DE/CD)______

65>___________simulator assumes that the time is continuous and an event may occur at any time

(DE/CD)

66>In DE simulator, components are ___________in the sense that if an output event is computed

from an input event, then the time stamp of the output event should not be earlier than that of the

input event.____________ components require the simulators to be able to roll back in time and

they may not define a deterministic behavior of a system (causal/non-causal)

67>_____simulator is more accurate than a______ simulator and as a consequence ______can run

slower (CD/DE)

68>___________simulators are considered as good as actual implementation because of their

continuous notion of time and discrete notion of events (CD/DE)

69>Following are extensions of classical network simulators

a: ns-2

b: J-Sim (java sim)

c: GloMoSim/QualNet

Ans: ___________ (a/b/c/all)

70>Another class of simulators called___________ simulators incorporate the actual node software

ino the simulation

a: software in the loop

b: hardware in the loop

Ans: (a/b)

71>Following are examples of software in the loop simulators

a: TOSSIM for Berkeley motes

b: Em* for Linux based moses such as Sensoria WINS NG platforms

Ans: ___________ (a/b/both)

72>___________is an open source network simulator that was originally designed for wired, IP

networks (nesC/ns-2)

73>following are efforts to extend ns-2 to simulate sensor networks

a: SensorSim from UCLA

b: NRL sensor network extension from the Navy Research Laboratory

Ans: ___________ (a/b/both)

74>___________aims at providing an energy model for sensor nodes and communication, so that

power properties can be simulated (SensorSim/NRL sensor network )

75>___________provides a flexible way of modeling physical phenomena in a discrete event

simulator (SensorSim/NRL sensor network)

76>The main functionality of ns-2 is implemented in _____, while the dynamics of the simulation is

controlled by______ scripts (C/C++/perj/Tcl)

77>The key advantage of ns-2 is its rich libraries of protocols for nearly all network layers and for

many routing mechanisms (true/false)___________

78>DSDV stands for___________

79>DSR stands for___________

80>AODV stands for____________

81>TORA stands for ______


TCP: directed diffusion, GEAR & GAF routing

MAC: DSDV, DSR, AODV & TORA

Adhoc routing: 802.3, 802.11 & TDMA

Sensor network routing: reno, tahoe, vegas & SACK implementation_______

83>___________is dedicated simulator for TinyOS applications running on one or more Berkeley

motes (TOSSIM/ns-2)

84>___________uses a simple but powerful abstraction to model a wireless network (TOSSIM/ns-2)

85>___________has a visualization package called TinyViz , which is a java application that can

connect to TOSSIM simulations (TOSSIM/ns-2)

86>___________is the basis for onus signal and information processing algorithms (state

theories/system theories)


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87>___________group is a set of entities that contribute to a state update (collaborative/co-

operative)

88>In collaboration group, the entities can be physical sensor nodes or they can be more abstract

system components. Such entities are referred to as___________ (actors/agents)

89>A collaboration group provides following abstraction

a: its scope to encapsulate network topologies

b: its structure to encapsulate communication protocols

Ans: ___________ (a/b/both)

90>_____of a group defines the membership of the nodes with respect to the group._____ of a

group defines the roles each member plays in the group and thus the flow of data (scope/structure)

91>A group is a 4 tuple G= (A, L, p, R)

where __is a set of agents, __is a set of labels called roles, __is a function that assigns each agent a

role and__ are the connectivity relations among roles

92>GCG stands for___________

93>n-HNG stands do___________

94>Following protocols can be used to support the communication among members even in the

presence of communication holes in the region

a: GEAR

b: Mobicast

c: Geocasting

Ans: ___________ (a/b/c/all)

95>TinyDB is built on ______HNG group (0/1/infinite)

96>PSG stands for___________

97>___________consists of members within a pre-specified geographical extent (GCG/n-

HNG/PSG/AG)

98>___________has an anchor node and defines that all nodes within n communication hops are

members of the group (GCG/n-HNG/PSG/AG)

99>___________comprises consumers expressing interest in specific types of data or service and

producers that provide those data or services (GCG/n-HNG/PSG/AG)

100>In___________, a member belongs to the group because it was invited by another member in

the group (GCG/n-HNG/PSG/AG)

101>PIECES stands for__________

102>__________is a software framework that implements the methodology of state centric

programming over collaboration groups to support the modeling (TOSSIM/PIECES)

103>PIECES comprises __________ (principals/port agents/both)

104>In PIECES, ____is the key component for maintaining a piece of state whereas______ may be

an input, an output or both (principals/port agents)

105>In PIECES, an output port agent is called__________ (anchor/observer)

106>In PIECES, _____observer pushes data autonomously to its destinations while_____ observer

sends data only when a consumer requests it (passive/active)

107>In PIECES, the execution of principals and port agents can be__________ (time driven/event

driven/either)

108>PIECES imposes the restriction that whenever an agent is triggered , its execution must have

reached a quiescent state. Such a trigger is called__________ (restrictive trigger/responsible

trigger)

109>In PIECES, __________maintains a piece of local state related to the physical phenomenon,

based solely on its own local measurement history (physical principal/sensing principal)

110>PIECES simulator is implemented using a combination of__________ (java/matlab/C)

111>In PIECES simulator, an event driven engine is built in _____to simulate network message

passing and agent execution at the collaboration group level whereas a continuous time engine is

built in_____ to simulate target trajectories, signals and noise, and sensor front ends

(java/matlab/C)

112>Using the__________ centric model, programmers decouple a global state into a set of

independently maintained pieces, each of which is assigned a principal (node/state)

113>Following are kinds of target information that user cares about in the multi-target tracking

problem a: target positions b: target identifies

Ans: __________ (a/b/both)


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114>In multitarget tracking problem, there is a need to sort out ambiguity regarding which track

corresponds to which target. This problem is referred to as__________ problem (identity

management/location management)

115>In PIECES, MTTracker is implemented by following principals

a: tracking principal

b: classification principal

c: identity management principal

Ans: ___________ (a/b/c/all)

116>TinyOS, TinyGALS and nesC are examples of__________level operating systems and

programming languages based on the Berkeley mote hardware (state/node)

117>__________centric platforms typically employ a message passing abstraction of

communication between nodes (state/node)

118>Programming distributed systems beyond individual nodes has been traditionally handled by

middleware technologies such as__________ (COBRA/CORBA)

119>___________centric programming is aimed at providing domain specific programming models

for information processing applications in sensor networks (state/node)

ANSWERS

1>40

2>all

3>either

4>3,226

5>atomic

6>SC

7>norace

8>1

9>application

10>app_start()

11>signal processing specialist,networking expert

12>state

13>Sensoria WINS NG node

14>TinyOS,nesC

15>dedicated embedded sensor

16>Soc

17>Soc

18>Maxim DS1804

19>4

20>27

21>FSM

22>client server

23>tree structure

24>T

25>call,signal

26>both

27>nesC,TinyGALS

28>TinyGALS

29>TinyGALS

30>TinyOS,TinyGALS

31>app_init(),init()

32>PARAM_GET(),PARAM_PUT()

33>112,86

34>node

35>1-b 2-c 3-d 4-a

36>physical,mac and network

37>CD

38>DE

39>SensorSim


42

40>all

41>all

42>GCG

43>n-HNG

44>PSG

45>all

46>AG

47>either

48>PIECES

49>T

50>packet,collaboration group


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CHAPTER 8: APPLICATIONS AND FUTURE DIRECTIONS

1>The main problem with wired sensor networks is __________in deployment (cost/delay)

2>A__________ network is more time consuming to construct and deploy, precluding applications

where immediate data collection is needed (wired/wireless)

3>The size of wireless sensor system is limited mostly by

a: the cost of maintaining communication links

b: the cost of sensor hardware

Ans: __________ (a/b/both)

4>Following are application areas of wireless sensor network

a: asset and warehouse management

b: automotive

c: building monitoring and control

d: environmental monitoring

Ans: __________ (a/b/c/d/all)

5>Following are application areas of wireless sensor networks

a: health care

b: industrial process control

c: military battlefield awareness

d: security and surveillance

Ans: __________ (a/b/c/d/all)

6>DSRC stands for___________

7>NHTSA stands for___________

8>Sensors may be used

a: to monitor and track assets such as trucks or other equipment

b: to manage assets for industries such as oil and gas, utility , and aerospace

An: ___________ (a/b/both)

9>Sensors can be used

a: to monitor conditions and movements of wild animals or plants in wildlife habitats

b: to monitor air quality and track environmental pollutants, wildfires or other natural or man-

made disasters

c: to monitor biological or chemical hazards to provide early warnings

d: to monitor earthquake

Ans: ___________ (a/b/c/d/all)

10>___________sensors instrumented in a building can detect the direction and magnitude of a

quake and provide an assessment of the building safety (acoustic/seismic)

11>C3I Stands for___________

12>Ensuring security and privacy is one of the highest priorities for sensor network systems


13>PKI stands for___________

14>EmSoft Stands for___________

15>___________framework allows an application developer to write code for a sensor network

signal processing and tracking application using a state-centric model of programming

(TOSSIM/PIECES)

16>FFT stands for__________

17>___________algorithms refer to methods that require relatively little floating-point computation

and less memory storage than those that are floating point intensive such as FFT (lightweight signal

processing/lightweight signal regeneration)

18>___________information architectures deal with how information is organized and manipulated

in a sensor network (distributed/centralized)

19>Information double counting is a major problem for distributed inference

(true/false)___________


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ANSWERS

1>both

2>wired

3>both

4>all

5>all

6>Dedicated Short Range Communication

7>National Highway Traffic Safety Administration

8>both

9>all

10>seismic

11>Command, control, communication and intelligent

12>T

13>Public key infrastructure

14>Embedded Software

15>PIECES

16>Fast Fourier Transform

17>Lightweight signal processing

18>distributed

19>T

MULTIPLE CHOICE QUESTIONS WITH ANSWERS ON WIRELESS SENSOR NETWORKS

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