Is Chuong5 Phan1

8/13/2019 Is Chuong5 Phan1

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Chng 5: H tr gipra quyt nh

(Khi qut v DSS)Chuyn ngnh Cc h thng thng tin v tri thc

khoa CNTT-HSP HN- 2010 1


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WH Tdecision are involved

WHERE computers could help

HOW computers could help


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Gii thiu vDSS

DSS l g? Cc c trng v khnng ca DSS

Phn lp DSS

Cc thnh phn ca DSS

Cc cng c

Xy dng v ci t

Mt sm hnh

Case study3

Ni dung


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Mt sv d

Market Planning and reseach:

Operation and Strategic Planning

Sales Support


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Tt cdliu cn thit cho DSS/EIS l mt phn ca

TPS thng thng (Transaction processing system):thu thp dliu ny cc nhanh, real-time,..

Thng tin do DSS cung cp khng chc ch cho nh

qun l m cn c li cho khch hng


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Cc chc nng qun l

lp khoch

tchc nh hng v iu khin.

Ngi qun l bgn vo mt qu trnh lin tc ra quyt nh.

Qun l l nghthut: da trn ssng to, phn on phn

x, trc gic v kinh nghim (khng chl cc pp nh lng

ngngha theo cch tip cn ca KH).

Ngy nay, mi trng ca nh qun l thay i rt nhanh


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Speedy computations

Overcoming cognitive limits in processing and storerage Sales

Support

Cognitive limits

Cost reduction

Tehnical support

Quality support

Competitive edge


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DSS

GSS (Group support systems), including group DSS

EIS (Executive information systems)

ES (Expert systems)

ANN (Artificial neural networks)

Hybird support systems


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"Interactive computer-based systems, which helpdecision makers ultilize dataand modelsto solveunstructured problems" (Gorry and Scott Morton[1971]).

"Decision support systems couple the intellectualresources of individuals with the cabilities of thecomputer to improve the quality of decisions. It is acomputer - based support system for management

decision makers who deal with semistructuredproblems" (Keen ans Scott Morton [1978]


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L hthng thng tin (c bit) c sdng bi nh qun l (ban-hi ng ks tri

thc)

c sdng trong ra quyt nh

Sdng htrchkhng phi thay thcon ngi

trong ra quyt nh

c sdng khi vic quyt nh l na cu trc hay phi

cu trc.

Kt hp cht chvi mt CSDL no .

Kt hp cht chvi cc m hnh


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Nhng c im khng p dng cho mi hthngthng tin:

DSS thng sdng mt hay nhiu ni lu trdliu; DSS khng cp nht CSDL m dng nh mt ngun thng tin

ngoi;

DSS giao tip vi ngi ra quyt nh;

Ni chung, ngi ra quyt nh cung cp cho DSS nhng thng tin

cthxc nh quyt nh cn c to ra.


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File Drawer Systems: cho php truy cp trc tipn cc mc dliu

Data Analysis Systems: cho php thao tc trn d

liu bng ngha ca cc php ton c thit k

cho nhim v.

Analysis Information Systems: cung cp struy cp

n mt chui cc CSDL v m hnh nh


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Accounting Models: tnh ton mt dy cc khoch

hnh ng trn c scc nh ngha tnh ton.

Representational Models: c on mt dy hnhng trn c scc m hnh c nhng thnh phn

khng xc nh c


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Optimization Systems: cung cp hng dn cho

hnh ng bng vic sinh ra gii php ti u nht

qun vi tp rng buc Suggestion Systems: thc hin cng vic c c ch

dn n mt quyt nh c xut cthcho

mt nhim vc cu trc kh r rng.


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Kiu vtr cao hn theo mt ngha no c tt

hn kiu vtr thp hn hay khng?

KHNG

DSS mc cao hn l phc tp hn v chng gii quyt

nhiu hn trong tin trnh ra quyt nh, nhng chng

khng ph hp vi tnh hung ra quyt nh n gin hn.


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Data are the foundation of any decision support system.

High quality data are useful (relevant to decisionmaking),

valid (accurately measured),

reliable (reproducible),

timely (available in time to influence decisionmaking).


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Data systems that produce quality data often emphasize:

appropriate data collection schedules;

rigorous verification and documentation requirements; thorough validation procedures;

clear, accessible, and customized coding instructions;


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A DSS is not a single piece of technology (such

as a database, file server, or network). It is asystem for in orpor tingand integr tingdisparate data sources.


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Chskt hp phn cng vi mi trng hiu hnh

htrcho cc ng dng. DSS c thhot ng trn

mt splatform di y:

The central corporate system

The central system linked to other computers on users

desktops via a network

A separate system that obtains data from the central system

and provides it to users again usually over a network.

A freestanding system at the users desk.

A combination of the above.


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u im MIS staffs v ngi dng quen thuc vi hthng.

C sn phn cng cn thit dng cho hthng

ng dng DSS c thtruy cp CSDL trung tm trc tip lmmi thng tin

C thchy DSS phc tp

Hu ht c loi cng cDS nh kiu 4GLs, DBMS, phn mm

m phng , ES shell v EIS.


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Hn ch Hthng trung tm c thkhng ph hp vi la chn ca DSS.

C thvt qu chi ph ca mt my tnh nhlm nhim v.

C thdn dn p cc cng cphn mm (khng ph hp) vo

sdng trong DSS.

Tnh hi p c thbtc ng bi phn mm khc np vo h

thng. Giao din ngi dng thng khng ddng (v hthng ln)

Htrha yu


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u im Cho php mi phn ca ng dng c chy trong mt mi

trng phn cng/phn mm sao cho ti u i vi mi phn.

Tit kim gi phn cng.

Dmrng.

Nhiu ng dng, cng cpht trin phn mm c thit k

chy trong mi trng client/server c thgim c thi

gian v gi thnh pht trin cc ng dng.


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Hn ch phc tp hn hthng chgm 1 my tnh

MIS staffs phi quen vi hai hthng, thm ch c3 (kt ni hai

hthng client vi server).

An ton v bo mt trthnh mi quan tm ln

Tit kim gi phn cng lm mi trng client trnn a dng

v phc tp hn cc terminal trong mi trng a ngi dng.


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u im sdng web nh mt server

C thtruy cp tbt cu

C thtruy cp nhbt cloi phn cng no ta c.

Web thng dng, t ng dng DSS trn Web th khng cn

hun luyn nhiu cho ngi dng


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Hn chkhi sdng web nh mt server Tc truy cp web c thchm (Thit bphn cng cho truy

cp nhanh c tht hn mng cc bphc vcho mt vn

phng hin i).

Kthut thit kweb v DSS khc nhau. ha thng c

thm vo trang web nng hiu qutrnh din, nhng c th

lm chm qu trnh np thng tin cho cc ng dng.


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Hn chkhi sdng web nh mt server Nhiu ngi dng web chi trcho truy cp tnh theo pht.

Phc vcc ng dng trn nn web hay ng dng bt chc

web (web-base, weblike), cn c server mnh hn trng hpcung cp dliu cho cng sngi dng bng hthng

client/server.

Java l ngn ngthng dng pht trin cc ng dng chy

trn client, nhng khng c li thtrong thc thi (perfomance).


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Tch bit dliu htrquyt nh ra khi dliu tc nghip:

sdng c cu trc dliu ph hp vi ng dng htrra

quyt nh

tp hp dliu tnhiu DB khi kh trn ln trong cng mt

DB. Kt hp c dliu ngoi vo DB ca DSS

Trnh qu ti (overloading) cho my tnh (phc vDSS) cha cc DB

ly mt lt ct ca DB tc nghip dng nh mt c schung

cho vic ra quyt nh trong khi CSDL tc nghip tip tc thay i.


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u im khi sdng Data Warehouse (hoc DB ca DSS tch bit) :

Phn cng cho DSS c thc ti u ha

Thi gian hi p khng btrngi no (phn cng DSS khng cn

phi chia scho ng dng khc)

Khng tn ph nng cp hthng trung tm chy ng dng DSS.

(Tuy phi mt thm ph mua my tnh mi nhng vn cn rhn

nng cp my tnh trung tm).


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u im khi sdng Data Warehouse (hoc DB ca DSS tch bit) :

Mi trng data warehouse (khng cho trc tip cp nht) n

gin hn v trnh c nhiu li hn.

Hu ht cc server v minicomputer thn thin vi ngi dng

hoc c thto nn iu bi phn mm c giao din ngi

dng DSS bng ha.


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Hn chkhi sdng Data Warehouse (hoc DB ca DSS tch bit) :

Cn thit phi chuyn i dliu gia hai hthng, to ra Data

Warehouse v cp nht cho n.

MIS staffs phi quen thuc vi chai hthng.

Ton thcng ng ngi dng ssdng chai hthng. C

nhng ngi dng c2, vic chuyn lm vic ththng ny

sang hthng kia lm tn km thi gian


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Hn chkhi sdng Data Warehouse (hoc DB ca DSS tch bit) :

Dliu htrra quyt nh chc tnh thi snhn c

download tData Warehouse.

To Data Warehouse c thmt mt sgiv DSS c thkhng

phc vc trong khong thi gian . Nu vic cp nht c

thc hin ngoi gilm vic th bt tin cho nhng ngi vn

hnh hthng v phi chi trtin ngoi gi.


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Nhng DSS khng truy cp vo CSDL tp trung v ln

C thchy trn mt my tnh dnh ring cho DSS, thng l

minicomputer bn vi hiu nng cao.

C thtrn mt my tnh multiple-user sdng theo kiu chia s

thi gian. nhiu ngi dng c thchung nhau phn cng (nhng

mi ngi l mt user ca ng dng stand-alone trong chnh phn

mm m hdng)


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The distributed nature of these data sources presentsthree challenges that must be addressed before adecision support system can effectively produce usefulinformation:

Accessibility (MIS&DSS?)

Ownership

Interoperability


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ETL process is necessary when source data in a DSS

reside in separate, noninteroperable databases

ETL is 3-stage process designed to move data from

legacy source systems into interoperable format in the

DSS


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When these sources are not interoperable, the ETL

process must be used to edit, clean, and verify data

that is then stored in data warehouse for analytical and

reporting use.


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When these sources are not interoperable, the ETL

process must be used to edit, clean, and verify data

that is then stored in data warehouse for analytical and

reporting use.


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Conversely, if different database are initially designed

(or later adapted) to be interoperable, the need for an

ETL process is greatly reduced. When this is the case,

the ETL step can be replaced with a data

aggregator, a tool that simply locates and compiles

queried data rather than editing, cleaning, and

verifying it.


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An analysis tool is basically an instrument that

applies business rules or other logic to data in order to

derive meaning

This includes time series analysis, cost allocations,

data mining, and other user-driven manipulation and

investigation.


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Analysis tools are availbe in many softwareapplications (spreadsheets, other stand-alone

programs)

In DSS environment, however, analysis tools are

particularly powerful (rely on OLAP). They permit

users to browse, query, analyze, and summarize large

amounts of data in an efficient, interactive, and

dynamic way.


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Robust reporting tools are a major element of anyDSS.

They presenting information in multiple formats

(blend of text, tables, graphics) and in multiple

dimensions


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DSS reporting functions must serve a wide range ofusers-including novices and users with expert

analytical capabilities:

predefined (static) reports that require little systemexpertise and are ideal for users with typical information

needs;

dynamic (ad-hoc) report-generating capabilitiesthat

require greater understanding of both the data and thequerying technology, but allow users to investigate more

complex questions.


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In DSS, a dashboard serves as a user interface

that both

presentsinformation

enables a user to accessor compilenew data


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4 fundamental ways to obtain any software capability:

To purchase a turnkey package

To customize a package To use specialized tools or generators designed for

the task at hand

To write the necessary program form scratch


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The choice between packages (customized or not) andcustom software usually depends on 2 factors

The degree to which your needs resemble those of

many other organizations. The financial impact of the application, which

determines the value of getting exactly the capability

you want versus what you can get in a standardpackage.


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To help make specific decisions have been developed

for common decisions.

Many people make these decisions, so the potential market is

lagre.

The decision has financial importance to many of these

potential users

The underlying factors are the same for all of them

The support infrastructure-public databases that can providethe necessary to anyone, free or for small fee-already exists


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The major categories of specialized software used to

assist DSS development :

DBMS

Information Retrieval Packages Specialized Modeling Languages

Statistical Data Analysis Packages

Forecasting Packages Graphing Packages


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Few if any DSS would not take advantage of at least some

capabilities . However, important components of many DSS

cannot be satisfied by standard tools and are still written in

Programming language of some type

3-generation programming language

4-generation programming language


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The user (or users)

The intermediary

The DSS builder or facilitator

The technical support person

The toollsmith


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Obtainingand installingthe DSS hardware

Installing the DSS and making it run on its intended

hardware

Providing user accessto the system

Creatingand updatingthe database

Trainingthe users on the new system


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Documentingthe system for its user and for those who will beresponsible for maintaining it in the future

Making arrangement to support the users as the system is used

Transferringongoing responsibility for the system from its

developers to the operations or maintenance part of MIS group

Switchingover to the new system from previous methods of

making decisions or obtaining information to make them.

Evaluatingthe operation and use of the system.


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