Distributed development of simulation models for

harbour processes

A.G. Bruzzone*, R. Mosca*, P.D. EspostP, S. Vacante^ & A.

Carbone^

^Department of Production Engineering, University of Genoa,

via Opera Pia 15, 16145 Genova, Italy

CETENA, via Savona 2, 16100 Genova, Italy

^Liophant Simulation Club, via XXSettembre 28/10, 16121

Genova Italy

Email: agnostino@itim.unige.it

Abstract

The paper proposes advanced modelling techniques for developing simulatorsfor harbour environments; the authors outline the potential from combiningtraditional simulation models with new techniques such as web-basedtechnologies in supporting design and management of port facilities andmaritime services.

1 Introduction

The existing harbour simulations are focusing frequently in very detailedprocesses, therefore the user needs and the growing complexity of harbourlogistics require a global environment where to operate in order to beeffective. In the future the distributed logistics among different harbourswill require efficient support systems evaluating costs and times foroperative purposes and designing procedures, defining agreements andimproving facilities for strategic planning, The simulation is a veryeffective methodology to develop this kind of systems and today is possibleto reuse at low cost efficient techniques, already developed for otherapplications, in order to share this potential tools among distributed users.Harbour are complex industrial systems involving many entities and

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146 Maritime Engineering and Ports

different services; in this environment there are public authorities that rulethe maritime aspects, port authorities managing harbour spaces and layoutredesign and many different companies operating. This system is verycomplex due to the fact that the ship operations are multiple, parallel andeach procedure involves many sub-activities, constraints etc. Harbours aredynamic structures evolving in order to meet the market requirements andto improve the efficiency and safety; these aspects require application ofre-engineering techniques for a proper re-organisation and for supporting

design of new components as:1. New Operating Procedures2. New Terminals3. Requirements for New Systems (i.e. requirements for new tugs)

In effect the authors are proposing an approach based on an innovativeand extensive use of simulation in web environment in order to develop

wired decision support systems; the paper includes projects that have beenalready completed and also new researches under development.The Ship Handling and Terminal Management are certainly one of themain problems in harbour environment; in effect these processes areinteracting continuously: i.e. the planning of the docks influences the shiphandling procedures and yard planning. These problems are normallyrelated to many different entities (maritime authority, port authority,terminal owners, ship owners, harbour services etc.). For these reasons(system component interactions and user needs) it becomes very difficultto develop support systems operating as stand-alone packages; the authorsare proposing an approach that allows to develop a new generation ofsupport systems based on simulation and sharable on a wide context justby using existing technologies (i.e. web browser). The paper proposes thedevelopment of a conceptual model for a virtual harbour (includingterminal operations, ship handling) and an architectural proposal for theimplementation; this project in effect is based on previous simulationmodels developed by the authors and to the adaptation of these in order tooperate on a web based environment. In this case it's necessary tointegrate different models: continues simulation (i.e. ship movements,interaction among a ship and the tugs etc.) and discrete event simulation(i.e. terminal operations, maintenance management etc.). In order to shareefficiently this complex model on the web it becomes very critical toimprove the efficiency, so it is proposed to use combined simulationarchitecture. The proposal is under implementation based on Javalanguage; the user interface is based on Java graphics capabilities.

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Maritime Engineering and Ports 147

2 Harbour services and ship handling

A very interesting application area inharbour modelling is related to ship

handling; in effect these procedures involve the interactions among many

different entities (i.e. tugs, port pilots, boat men, ship etc.); this kind ofmodel could be successfully used for wide applications: training,

procedures design, layout re-engineering etc.; in the paper we propose two

different approaches in modelling the ship handling: the first one related to

the dynamics of the process in order to support training and ship design,the second one (POSEIDON) focusing much more on management/re-

engineering issues and based on combined stochastic simulation (discrete-

event plus continuous modelling).

2.1 Ship Handling Dynamics

The SIMON (Simulator of Ship Motions) ship handling simulator,

developed from CETENA is an example of dynamic simulator for ship

handling; it consists of four main elements:. mathematical model of the ship and of the environmental conditions;

• console reproducing the ship's bridge;

• computer generate image system;• computer with the capacity to run the program in real-time.The computer program represents the "heart" of the simulation systemsince it allows to describe in real-time the ship's dynamic behaviour, on the

basis of the orders to its propulsion, steering and auxiliary devices and of

the environmental conditions.The computer is connected to the console, on which the rudder wheel, the

engine telegraphs, and the various indicators and instruments necessary to

navigate the ship, are placed, and namely:. gyrocompass repeater; • turn rate display;

. rudder angle display; • echo-sounder display;

. engine rpm display; • log display;• propeller pitch display; • anemometer display.To perform a practical application the following elements have to be

known to undertake a navigability study:• Mathematical model of the ships considered in the study;

• Harbour lay-out;• Average and dynamic data about environmental conditions (waves,

wind and current);. Water depth of the area of interest;

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148 Maritime Engineering and Ports

• Characteristics of the auxiliary devices for berthing and un-berthing

manoeuvres of the harbour under consideration.

SIMON is mainly based on a mathematical model able to solve a set of

differential equations for the ship's four degrees of freedom and to takeinto account both the effect of environmental agents (as wind, waves,currents, shallow waters, etc.) and of external manoeuvring devices (astugs, mooring anchors, mooring lines, etc.); the simulations of the variousmanoeuvres are usually carried out by a Pilot of the port underinvestigation; the following auxiliary devices can be included in the

mathematical model of the simulator:Tugs Mooring anchors Mooring lines

This model is used as a "laboratory" not only to assess the ship's

manoeuvring capability, but also to establish a method for documenting

harbour navigability, its safety levels, potential of training scheme effectsof new bridge equipment, communication methods and procedures.

2.2 POSEIDON:

The POSEIDON (POrt Simulation Environment for Interactive Design ofOperation and Networks) had been developed by DIP and Liophant; thisproject starts considering the reality of two very different harbours: Genoa(Italy) and Riga (Latvia); in effect these realities are very different:

• Genoa needs to be reorganised for improving competitivenessconsidering changes in multimodal operations and development of hugenew terminal based on hub structure (i.e. passenger terminal, container

terminal)• Riga is a growing reality where it is important to introduce new

technologies (i.e. wireless communications, new handling devices asVan Carrier or transtainers), new procedures for handling ship withefficiency and safety; in effect there are simulation project in this portworking on the new improvement design.

In order to identify properly these requirements and support the design andre-engineering it's very useful to develop models reproducing the reality:this project proposes the modelling of all the components involving theship handling in the harbour and the requirements and operations ofsupport as services, tugs, pilots, etc.The model is developed in a distributed environment to be able in thefuture to support distributed operations among the different harbourentities. Web-based technologies can be used in order to distribute in avery user friendly way information, results and analysis tools; for thisreason it's very important to focus the attention on building-up a package

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Maritime Engineering and Ports 149

based on the concept easy to be used in terms of program standards,

Graphic User Interface (GUI), platform independence etc. In harbour

environment this aspect must be stressed due to the large number of

different skills of the potential users and to high requirements in terms of

efficiency, safety and all-conditions operations.We propose to build-up a Web-based environment able to integratesimulation models, user interface and advanced graphics (i.e. VirtualReality) in order to provide to the user a very realistic and friendlyenvironment. This system could be used in order to support planning,

safety and handling operation. Implementing the conceptual model by

JAVA, it's possible to allow to each user to move in the virtual harbour

and to interact in a platform independent environment.The Simulation model (directly implemented in Java) identifies the bestpath in order to move a ship to a specific dock destination and all therelated path for tugs, boat man and pilot yachts. The user, operating justby using a regular browser, will be able to define operations and,

analysing the results, identify the best path, the safety level (with windfrom some specific direction) and the report of the mooring procedure (i.e.total times, performance index). This kind of simulation is important forthe harbour services and ship users, because they can have a great supportin planning and design of procedures during the operations improving

efficiency, quality and reducing, for consequence, the costs.By means of the Internet/Intranet, harbour processes simulation techniquescould be discussed and improved. The presentation of simulation resultsover the Internet allows quick and easy communication between the user

and the developer of a simulation study.The verification of the simulation models is much easier for the user whenpresented as an animation over the Internet; in this model it was appliedextensively Verification and Validation procedures using Graphic, Logicand Statistical analysis (i.e. Mean Square pure Error Temporal Evolution

Analysis, fig 1).The project can be integrated into every multitasking environment without

disturbing or interrupting running processes. The user conceptdistinguishes between three classes of users: Developer, Animation

Developer and Animation User.While the Animation user just works with a given animation, theAnimation Developer is allowed to build new control modules and

animation. The Developer is allowed to change main modules.The design of this project is carried out using an object - orientedapproach and the Java code; the advantage of this language is thepossibility to use and adapt different structures for the development of the

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150 Maritime Engineering and Ports

project; for this reason it is easy to create proper design object

architecture.Actually, the design of the project is based on carrying out the map of aharbour, using the geometrical co-ordinates, and evaluating the differentalternative paths for ships in order to calculate the best for each dock, andfor the other vessels that move in the harbour for service to the ships in themooring procedures (i.e. tugs, pilot - yachts, and moor-man boats).With this approach the ship-pilot/harbour personnel, identifies the trafficof the ships and distributes them in different paths in order to allow to theships to reach the chosen dock in the best way and the less time.The model provides as target function the mean service time (average timeto be handled to the dock from out of the harbour).Looking forward to the implementation phase the developed was forced todesign the conceptual model using OODA (Object-Oriented Design &Analysis); the operations that each ship must execute are carried out inthis simulator based on the logic presented in fig.2.The model is based on combined simulation integrating stochastic events

(i.e. ship arrivals generated by montecarlo extractions from statisticaldistributions based on historical data) with the continuous behaviour ofvessels and yacht movement in the harbour.During the simulation the ship before moving to the harbour meets withthe arriving pilot yachts, and only after that the pilot is on board continuesthe navigation inside the harbour up to the next point in which the tugs arewaiting.When this procedure is completed, the ship moves continuously up to thedock, and in proximity of this, there is the meeting with boat men and thebeginning of the different operations carried out by the tugs, the mooringboats and the personnel waiting in the dock for berthing.When this procedures are completed, the ship begins the procedures ofloading/unloading; at the end of loading/unloading the ship starts the otherprocedures necessary for going out the harbour, like to call for the pilotand the tugs to leave the dock; when the operations are completed by themooring men, the ship could move out, leave the tugs and proceed up tothe rendez-vous point with the pilot boat for unloading operation and then

could begin the navigation.The simulation model is implemented in Java so it's platform independentand it allows to be distributed and tested on the web just using a regularbrowser (see figure 3).

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Maritime Engineering and Ports 151

Table I : Independent Variables

A Harbour Traffic Maritime Line Arrival

B Pilot ResourcesC Tug ResourcesD Mooring Resources

Int.

The project is based on DOE (Design of Experiments); by applying acentral composite design considering the following independent parameters(table I); it was possible to perform on each target function (Table II) the

sensitivity analysis as shown in figure 4.For comparative analysis it was implemented the same conceptual model

using Arena™ simulation tool (simulator APS); in this case we obtain

equivalent results as presented in table III and figures 5; in effect weidentify a fast developing time using simulation tools respect multipurposelanguages; by other point of view the Java model, in addition to the webcapabilities, allows also to process more detailed statistical information.

Service TimeMean Square Pure Error

0 SO 100 160 200 250 300

Figura 1: Mean Square Pure Error.

Table II: Target Functions

Yl Arrival Times of Navigation Lines

Y2 Harbour Productivity

Y3 Use Coefficient of Pilot Resources

Y4 Use Coefficient of Tug Resources

Y5 Use Coefficient of Mooring Resources

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152 Maritime Engineering and Ports

Navigation

Departure

PilotUnBoard.

TugsDeparture

Tugs&Boat Men

UnMooring

Loading / Unloading

Fig.2 Harbour Services in Ship Handling

,%/ " , "*,<• V %9A *###a# \^~~^ "I N&##5&382

* v *v/ . v ^ ^ 8|jajR»*».. " - * ,Y- %%j?% ^: v'<" »411

» VVWVf AVJ< 5S«« ^ % .V

Figure 3: Platform Indipendent Simulator User Interface

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Maritime Engineering and Ports 153

100 -i

Use Coefficient of Mooring ResourcesMulti-Effect Sensitivy Analysis

A Harbour Traffic Maritime LineArrival Int.B Pilot ResourcesC Tug ResourcesD Mooring Resources

0,05 Effects 0,00

Fig.4 Effects of the Independent Variables and their Combinations

Service Times

56 -

55 -

="54£«E 53

1 52^

51 -

50

Fig.5

/ j

-«- Mooring* Unmooring-#- Average Mooring Service Time••x-- Average Unmooring Service Tin

TransientSteady-State

, i . *Z. ;: ^ -^*"- •*••• -«'•'

3 2 4 6 8 10 12Simulation Days

Experimental Analysis

Table III Model Comparisonjp.? PI

Use Coeff. Pilot Boats 1 9 %

Use Coeff. Tugs 22 %

Use Coeff. Mooring Men 1 7 %

Service Times [min] 1 08

Productivity [ship/day] 5 .0

Mn-c Min Meat22% 16% 4.3

27% 15% 189

23% 14% 149

123 98 109.

6.0 4.2 5.2

ne

14

?SR PON1 ,STD/o 0.8%

4> 2.6%

<, 2.4%

7 7.58

0.85

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154 Maritime Engineering and Ports

Conclusions

The papers provide an overview about different approaches forreproducing and analysing the ship handling in harbours; in particular thepotential of Web-Based modelling has been consider as an innovative anduseful approach for distributing in easy way the simulation among the usercommunity; the results of the implementation in term of efficiency andvalidation capability was satisfying, and now the authors are evaluatingthe possibility to VRML 2.0 as additional advanced interface (3Dinteractive environment).

References

[1] Bruzzone A., Signorile R. (1996) "Genetic Algorithms and Simulationas Support for Planning a Port Terminal", Proc.of ESS'96, Genoa

[2] Bruzzone A.G., Manetti E., Cotta G., Cerruto M.(1997)" Simulation& Virtual Reality To Support The Design of Safety Procedures In

Harbour Environments ", Proceedings of ITEC97, Lausanne (CH)[3] Capurro G (1995) "Program SIMSUP: A tool to Verify compliance

with the IMO Standards", Proceedings of MiniSymposium on ShipManoeuvrability, Fukuoka, Japan

[4] Delia Loggia B, Capurro G (1993) "Application of Ship Handlingfor the Design of Harbour Layout" AIPCN-PIANC Conf, Genoa

[5] Delia Loggia B, Capurro G (1996) "Simulation Approach to Shipand Harbour Design", Proceedings of Simulation in Industry, Genoa

[6] Giribone P. & A.G.Bruzzone (1995) "OO Modeling of an AGVSystem for a Harbor Environment", Proc.of WMC95, Las Vegas

[7] Mosca R., P.Giribone, A.G.Bruzzone (1994) "Graphic, Analog andStatistical Verification of a Computer Simulation of Port Operations",Proceedings of HPC94, San Diego, April 10-15

[8] Mosca R, Giribone P. & A.G. Bruzzone (1995) "Concurrent Design:Coal Bulk Terminal Design Based On Integrated SimulationMethods", Proc. of Summer Simulation '95, Ottawa, July 23-26

[9] Mosca R, Giribone P., Bruzzone A.G. (1996) "Study of MaritimeTraffic Modelled with Object-Oriented Simulation Languages", Proc.of WMC'96, San Diego, January 14-17

[10] Mosca R, Giribone P. & A.G. Bruzzone (1996) "Simulation of DockManagement and Planning in a Port Terminal", Proc. of MIC'96,Innsbruck, February 19-21

Transactions on the Built Environment vol 36, © 1998 WIT Press, www.witpress.com, ISSN 1743-3509