115
1 INTRODUCTION
In the era of e‐Navigation, the future VTS(Vessel
Traffic Services) is anticipated to play an important
role on the enhancement of maritime safety and the
efficiencyofmaritimetransportasa key stakeholder
of e‐Navigation. To enhance VTS services, VTS
operatorneedstheadvancedfunctionstosupportthe
VTSServices.
IntheIMOResolut
ionA.857(20),thethreeservices
for VTS are defined (IMO. 1997a), i.e., INformation
Service(INS), Navigational Assistance Service(NAS),
andTrafficOrganizationService(TOS).Amongthem,
the TOS concerns the operational management of
trafficandtheforwardplanningofvesselmovements
to prevent congestion and dangerous situations, and
ispart
icularlyrelevantintimesofhightrafficdensity
or when the movement of special transports may
effecttheflowofothertraffic.TheTOSisaserviceto
prevent the development of dangerous maritime
traffic situations and to provide for the safe and
efficient movement of vessel traffic within the
declared VTS area. It also includes establishing
priority of movements,allocat
ing space, routesto be
followed, speed limits to be observed or other
appropriatemeasureswhichareconsiderednecessary
by the VTS authority (IALA. 2012a). Taking intothe
IALAVTSstrategypaperaccount(IALA.2012b),itis
expectedthat the fut
ure VTS focuses on further
development of TOS in its operation. In the 35
th
sessionofIALAVTScommittee,thedraftguideline
ontheprovisionofVTSTypeofServicewasfinalised
(IMO. 2012b). In contrast to a general definition of
TOS in A.857 (20), the VTS draft guideline defines
concreteservicesforTOS(IALA.2012c).Ontheother
hand, various roles of e‐Navigation stakeholders are
included in it
s architecture specification process
(IMO.2012b),i.e.,therolesformaster,pilot,andVTS.
Inthispaper,theVTSfunctionstosupportitsTOS
arerevisited,consideringthereportsofe‐Navigation
strategyand IALAVTScommittee.Severalfunctions
to support the TOS are exemplified. Such funct
ions
Functional Requirements to Support Traffic
Organization Service
J
.S.Jeong&G.K.Park
DepartmentofMaritimeTransportationSystem,MokpoNationalMaritimeUniversity,MokpoCity,RepublicofKorea
ABSTRACT: In the era of e‐Navigation, the fut
ure VTS is anticipated to play an important role on the
enhancementofmaritimesafety andtheefficiencyofmaritimetransportasakeystakeholderofe‐Navigation.
The VTS services need the advanced Traffic Organization Service(TOS). In this paper, the VTS functions for
TOSisrevisitedfromthereportsofIMOe‐NavigationCorrespondenceGroupandIALA VTSCommittee.In
Korea, the research a
ctivities to enhance the existing VTS functions have been conducted. In terms of TOS,
someVTS functions have beendeveloped.Inconclusion,all the pasttrafficdata and real‐timeship data are
requiredtoprovidetheadv
ancedTOS.Forthis,theadvancedfunctionstosupportTOSshouldbeimplemented
onVTSconsole.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 7
Number 1
March 2013
DOI:10.12716/1001.07.01.15
116
need to be presented on the VTS console for an
effectiveVTSoperation.
2 TRAFFICORGANIZATIONSERVICESFORVTS
2.1 Functionstobecarriedoutintheeraofe‐Navigation
In e‐Navigation, a stakeholer – a person or an
organization – may have several different
responsibilities. All functions
to fulfil the
responsibilities may be carried out by persons or
systems,oracombinationofboth(IMO. 2012b).The
functionsaresortedbystakeholders,i.e,master,pilot,
tug service providers, shore organizations. Table 1
represents main functions to be conducted by a
stakeholder(IMO.2012b).
Table1.Functionstobeconductedbyastakeholder.
_______________________________________________
StakeholdersFunctions
_______________________________________________
MasterSupportandControlNavigation
SafeNavigation
ManagementofInformation
Support to Incident Handling and
EmergencyManagement
SupportMaritimeSecurity
PilotPreparePilotage
ConductPilotage
Onshore FairwayUtilizationPlanning
VesselTrafficServices
PortOperationSupport
EmergencyManagement
_______________________________________________
InTable1,allthefunctionsofstakeholderscontain
their sub‐functions. Several sub‐functions need to be
supported by shore organization, such as VTS. For
example, the function, Support and Control
Navigation, requires to use shore‐based information
services, i.e, Maritime Safety Information(MSI)
Service,RouteingInformation Service, Hydrographic
Information Service, Ice Information Service, Port
Authority Instruction, Meteorological Information
ServiceandWarningsoon.
Itisnaturalthat each function is alsointerrelated
to other function. The function, Vessel Traffic
Services,includes‘MonitorHighSeas’,‘ManageVTS’,
‘Manage Tracking Information’, ‘Operate Ship
Reporting System’, ‘Exchange Information with
Relevant Authorities’, ‘Exchange
Information on
Emergency’. The TOS is a crucial service for the
effective management of VTS. In the era of e‐
Navigation,theVTSrequireanintelligentTOSwhich
containsthefollowingsub‐functions:
PlanTrafficFlow
PlanTrafficOrganizationCriteria
MonitorTrafficSituationandPrediction
Decide
onPriority–e.g.allocationoftimeslots
2.2 IALA VTSTrafficOrganizationServices
Inthe35thsessionofIALAVTScommittee,thedraft
guidelineontheprovisionofVTSTypeofServicewas
finalisedandissupposedtobedeliveredtotheIALA
Councilforapproval(IALA.2012d).Asmentioned
in
theIALAVTSStrategyPaper(IALA.2012b),theTOS
willbefurtherdevelopedoverthenext10to20years.
Itisexpected thatthefutureVTSoperationfocuseson
the delivery of the advanced TOS. The IMO
Resolution A.857 (20) states that a VTS should at all
times
be capable of generating a comprehensive
overview of the traffic in its service area combined
with all traffic influencing factors. To respond the
traffic situations developing in the VTS area and to
determine appropriate actions, the acquired data
shouldbeprocessedandevaluated.Asmentionedin
Section 1, the TOS is
a service to prevent the
developmentofdangerousmaritimetrafficsituations
andtoprovideforthesafeandefficientmovementof
vesseltrafficwithinthedeclaredVTS area.Thedraft
guideline suggests the cases that the TOS should be
providedasfollows(IALA.2012c).
vessel movements need to be
planned or
prioritised to prevent congestion or dangerous
situations;
special transports or vessels with hazardous or
pollutingcargomayaffecttheflowofothertraffic
andneedtobeorganised;
anoperatingsystemoftrafficclearancesorsailing
plans,orboth,hasbeenestablished;
theallocationofspace
needstobeorganised;
mandatory reporting of movements in the VTS
areahasbeenestablished;
specialroutesshouldbefollowed;
speedlimitsshouldbeobserved;
the VTS observes a developing situation and
deems it necessary to interact and coordinate
vesseltraffic;
nauticalactivities (e.g. sailing
regattas) or marine
worksin‐progress(suchasdredgingorsubmarine
cable‐laying)mayinterferewiththeflowofvessel
movement.
Here is an example of the TOS information with
relationtowaterwaymanagement(IALA.2012c).
Theuseofonewaytrafficasanalternativeoftwo
way traffic, depending
on the dimensions of ship
ortheweatherconditions;
Organising other traffic when a vesselhas
passedpointofnoreturn;
Slot management to allocate ships in a time
window;
Organising the traffic concerning vessel
dimensionsincomparisontofairwayrestrictions;
Instructvesselswhenovertakingis
notpermitted;
Establishandorganiseshipsafetyzonesincaseof
particularoperations;
Establishandorganiseexclusionzones;
Instruct vessels to keep clear from special
areas/positions;
Organisingthetrafficasregardstometeorological,
hydrographical or other restrictions such as
visibility,windspeed,current,seastate,andunder
keelclearance.
117
3 VTSFUNCTIONSTOSUPPORTTOS
3.1 ExamplesofFunctionsforTOS
Toprovide the TOS,asmentionedinsection2.1and
2.2, the VTS requires further information, which is
obtainablebyimplementingthefollowingfunctions.
ShipReportingSystem(SRS),SailingPlan(SP)and
informationtransferamongauthoritiesandship.
Calculat
ionoftrafficcongestionrateinthewater‐
areaofinterest
Decision‐makingforcollisionavoidance
Monitoringofshiptrajectories
Riskassessmentinthewater‐areaofinterest.
3.2 ShipReportingSystem,SailingPlan,and
InformationTransfer
TheinformationwhichiscollectedfromSRScontains
ship particulars, ship’s draft, spatial and tempora
l
information of ship movements, cargo type. Such
information may be utilised to organise the ship or
othershipsinafairway,toallocatetheshipsinatime
window, and also to keep clear from special
areas/positionssoon.TheSPmaybeusedtoprovide
va
rious services belonging to TOS, i.e, wateway
managementandcollisionavoidanceetc.
3.3 CalculationofTrafficCongestionRateinthe
Waterareaofinterest
Large part of the TOS may be conducted by
predictingthedirectionoftrafficflowanditsvolume.
AllinformationfromSRSand/orSPmaybeusednot
onlytopredictsucht
rafficflowprediction,butalsoto
predict the area to be congested. The static and
dynamic information from non‐AIS ships should be
combinedwithalltheinformationfromSRSandSP.
Figure1.LateraldistributionofTrafficalongafairway.
Thelateraldistributionoftraffichelpsnotonlyto
understandtrafficflowdirection but also to mitigate
thecongestionbyallocatingtrafficroute. In addition
to the spatial distribution of traffic, the speed
distribution can be also used to calculate the traffic
congestion rate in a time window as well as in the
specialarea.Thet
rafficcongestionratemaybesimply
calculated from the ratio of the total ship bumper
areasoverthetotalwaterareainafairway.However,
the ship speed affects the number of ships in a
fairway and the distance among ships. To obtain
more practical congestion rate, it is realist
ic to
consider the other parameters including ship
particulars, ship dynamic conditions, courses,
weather, sea state. The calculation of traffic
congestion rate is open. Figure 1 shows the lateral
distributionoftrafficwhichisobtainedfromthedata
collectedalongafairway.Thelateraldistributionina
fairwaycanbepl
ottedatarbitrarygatelineofinterest.
Figure 2 representsthe distribution of ship speed
at the observed area or a fairway. From the speed
distribution, the average and standard deviation of
speedarecalculated.Thestandarddeviationofspeed
will affect a navigational safety in waterarea.The
speeddistributioncanusetodeterminethesafespeed
orthespeedlimitcrit
eria.
Figure 3 shows CPA distribution as TCPA varies
with time at the waterarea of interest. The CPA is
normalizedbythemajordiameterofanellipticmodel
forshipbumperarea(A.G.Frandsen.1991).InFigure
3, the red dot line mea
ns the boundary of ship safe
domain.Ifavesselentersintotheboundaryoftarget
vessel,thetwovesselsmaybeindanger.
Figure2.ShipSpeedDistribution.
Figure3.CPAvariationasafunctionTCPA.
3.4 RiskAssessmentandDecision‐MakingforCollision
Avoidance
Several risk assessment models have been proposed
to represent real‐time collision risk among multiple
encountered vessels in a water‐area (Y.S. Park et.al.
118
2012). The collision risk, which is calculated by
method proposed in (Y.S.Park et.al. 2012, N.S.Nam
&S.Y.Kim,2012),maybeusedasareferenceindexto
support decision‐making for collision avoidance in
VTS or ship. On the other hand, the other models
assess statistical risks by
using the past ship
movement data (Jun Min Mou. et al. 2010, Jakub
Montewka.etal.2010,J.S.Jeong.et.al.2012).Figure4
shows the variation of causation factor which is
calculatedbyusingAISdataforthelast72hours(J.S.
Jeong. et al. 2012) in WANDO waterway of
Korean
Southwesterncoast.Thecausationfactoriscalledthe
probability of failing to avoid a collision when the
encountered vessels are on a collision course (Jakub
Montewka.etal.2010).Infact,itisdifficulttoassess
themaritimeriskbycausationfactoritself.Thevalue
ofcausationfactormaybe
usedasreferenceindexfor
design of traffic lane, determination of speed limit
and fairway width so on. The proper range of
causation factor depends on natural environments
includingweather,geographicalconditions.
Figure4.Variationof
C
P
for72hours.
4 CONCLUSIONS
ItisexpectedthattheTOSplaysanimportantroleon
the future VTS operation. Herein, the VTS functions
in the e‐Navigation architecture and IALAdraft
guideline on the provision of VTS Type of Service
wererevisited.TosupporttheadvancedTOSandthe
decision‐making for effective
and safe waterway
management, several examples were illustrated. The
information from ship reporting system and sailing
plan may be utilized to organise the ship or other
ships in a fairway, to allocate the ships in a time
window, and also to keep clear from special
areas/positions so on. The traffic
congestion level is
usefulforthedynamicassignmentoftrafficlaneand
width,andevenspeedlimit.Themaritimeriskindex
alsohelpstomanagetrafficeffectiveandsafelyandto
designtrafficlaneandcapacity.
To take a proactive measures for maritime safety
and prevention of oil pollution, the advanced
functionsonVTSconsoleshouldbeimplemented.
ACKNOWLEDGMENT
This research was a part of the project titled
“Development of the Intelligent Technology for
MarineAccidentProtection&Salvage”fundedbythe
Ministry of Land, Transport and Maritime Affairs,
RepublicofKorea.
REFERENCES
IMO. 1997a. Guidelines for Vessel Traffic Services,
ResolutionA.857(20).
IALA.2012a.VTSManual2012Ed.5:50.
IALA.2012b.StrategypaperaddressingthedeliveryofVTS
inarapidlychangingworld,VTS35/output/2.
IALA. 2012c. Guideline on Provision of Vessel Traffic
Services(INS,NAS,TOS),Ed.1.
IMO. 2010b. Development of an e‐Navigation Strategy
Implementation Plan, Report of the Working Group,
NAV56/WP.5.
IALA. 2012d. Report of the 35
th
Session of the IALA VTS
Committee.
A.G.Frandsen. 1991. Evaluation of Minimum Bridge Span
Openings – Applying Ship Domain Theory, Transport
ResearchRecordNo.1313,Pub.No.743B:pp.85‐86.
Y.S.Park.J.S.Kim.J.Y.Jung.J.S.Jeong.&G.K.Park.2012.A
StudyinthemaritimesafetymodelinKorea,ENC
2012,
25‐25April,Gdansk,Poland.
N.S. Son. S.Y. Kim. C.S. Lee. 2012. On the Monitoring
System of Collision Risks among Multiple Ships, ENC
2012,25‐25April,Gdansk,Poland.
Jun Min Mou. Ceesvander Tak. & HanLigteringen. 2010.
Study on collision avoidance in busy waterways by
usingAISdata,
OceanEngineering(37):483‐490.
Jakub Montewka. Tomasz Hinz. Pentti Kujala. & Jerzy
Matusiak. 2010. Probability modeling of vessel
collisions, Reliability Engineering and System Safety (95):
573‐589.
J.S. Jeong. K.I Kim. & G.K. Park. 2012. Risk Assessment
Model of Maritime Traffic in Time‐Variant CPA
Environments in Waterway, Journal of
Advanced
Computational Intelligence and Intelligent Informatics
16(7).
