189
1 INTRODUCTION
Safe navigation and vessel traffic management
requireaccesstorelevantinformationanditsproper
use.Moreandmoreinformationsystemsareinstalled
on ships and in land‐based centres. These systems
processdataofvariouscontentandform,essentialfor
transport process participants: navigators,
shipowners, marine agents, shipchandlers, recipients
of goods and services, port operators, vessel t
raffic
servicesand others. The variety of physical
characteristics, sources, types and scope of
navigational information hampers its acquisition,
collection,management,processing and presentation
todecision makers. Thedevelopmentof information
technologiesmakesitpossibletostandardizetheform
of navigational information and interchange
processes, which ma
y significantly contribute to the
enhancementofshippingsafety andeffectiveness.To
thisendsuchconceptsase‐maritimeande‐navigation
are developed along with implementation of
international projects, including those executed
withintheEU(e.g.MARNIS[5],MonaLisa[6]).
Theassuranceofsafeshipping,eoip
sothesafetyof
personnel, cargo, ships and environment depends,
apart from information access and possibility of its
automaticinterpretation,oncommunicationaimedat
determining or accurately specifying the
interpretation and assessment ofa current and
predicted situation as well as intentions of other
transport process participants. In maritime shipping
the principles of communication between navigators
steering their respective ships and navigators and
land‐ba
sed canters are set forth in relevant
regulations.Althoughtheregulationsimposecertain
obligations on traffic participants, they do not
eliminate possibilities of dangerous situations,
resultingfromfailuretostartcommunicationorfrom
errorsincommunications.Examplesofthel
atterare:
improperchoice of means of communication,wrong
information, misunderstanding or misinterpretation
of interchanged information. One way to solve this
Information Exchange Automation in Maritime
Transport
Z.Pietrzykowski,P.Banaś,A.Wójcik&T.Szewczuk
M
aritimeUniversityofSzczecin,Szczecin,Poland
ABSTRACT:Toensurethesafetyofma
ritimetransporttheaccesstoinformationmustbeprovidedthrough
acommonlyusedservices.However,anequallyimportanttaskistodetermineoragreeoninterpretationof
incomingdataandassessmentofacurrentandpredictednavigationalsituationand,infurtherstep,intentions
of the part
icipants in the transport process. Thanks to the standardizationof information format, automatic
informationexchangegetsincreasinglywider.Anotherstepaheadisautomaticinterpretationofinformation
and automation of negotiation processes‐intelligent communication. Rapid development of IT and ICT
technologiescreatessuchopportunities.Thisarticlepresentstheresultsofresearchonasystemofa
utomatic
communicationandco‐operationinmaritimetransport.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 8
Number 2
June 2014
DOI:10.12716/1001.08.02.03
190
problem can be the development of principles of
automaticcommunicationandco‐operation,basedon
standardsofnavigationalinformation.Thismeansthe
need to extend navigational ontology with a sub‐
ontology for communication processes, and
applicationofaformallanguagetowriteitdown.
2 STANDARDIZATIONOFINFORMATIONFORM
Manysystemsandequipmentforma
rinenavigation,
supporting decision processes on board, have been
designedanddevelopedforyears.Theirvarietycalls
for standardization of navigational information
format. One such example is S‐57 standard for
hydrographic data, used in electronic navigational
charts.
AuthorsoftheS‐100standard(version4.0 ofS‐57)
[3]aim
edatcreatingpossibilitiesforaninterchange,
through this standard, of more source hydrographic
data and related products. In practice it means the
handlingofvariousdata:matrix,raster,technical3‐D,
time‐varying(x,y,z,time)andnewapplications,for
instance high‐density bathymetry, bottom
classifications, ma
rine GIS. The S‐100 standard may
also be useful in services, based on Internet
technologies, offering searching, viewing,analysis
andtransmissionofanytypeofhydrographicdata.
TheS‐100 standardofferswide possibilitiesof its
implementation in any structures, with the use of
dataformatsselectedbytheuser.
Thestandardhasthefollowingcharact
eristics:
flexibility in introducing changes; future
specifications of products will be based on one
main data model, that will be expanded
dependingontheneedsofvarioususergroups;
archive located on the IHO website will include
dictionaries of features and attributes (wit
hout
obligatory relations between them) and product
specifications, which will enable their flexible
development;
separatefoldersforeachusergroup;oneofthem‐
folder S‐57 will comprise new features and
attributesandadditionalspecificationsofproducts
that may be made, specification of user data
exchangestandard.
The sub‐standard S‐101 [3] is a new ENC
specificat
ionbasedontheS‐100concept,i.e.flexibility
and arbitrariness of using source data based on
catalogues and rich geometric models, information
types and their attributes. Such form of data
distribution enables introduction of new
functionalities in ENC charts, such as dynamic
presentation of ti
dal streams or very accurate
bathymetric data. Utilizing such an amount of data
may contribute to making better decisions and
avoidingerrorsinportapproachchannelsorwhena
ship proceeds in heavy traffic waters. The
specificationofproductsbasedonbathymetricdatais
foundinS ‐102sub‐standard[8]tha
tcanbedeveloped
independently or in combination with S‐101, e.g. in
ECDIS.
Theautomaticinformationexchangeprocesscalls
fordefiningtheontologyofnavigationalinformation,
messages sent and formats of recording. This is
importantintheprocessoftransmittinganintention,
questionorrequest(demand).Sofar,crisptermshave
been used in ship‐to‐ship or ship‐to‐shore
communication, but under the S‐100 standard non‐
crisptermswillbepossible.
Data exchange a
utomation and broadly
understoodco‐operationalsorequirethespecification
and standardization of data format and scope, and
procedures of automatic translation. It seems
necessary to develop a sub‐standard tha
t would
define these parameters of data exchange between
vessels (mobile objects) and between land‐based
centres and vessel operators, automatically, semi‐
automaticallyormanually.
3 NAVIGATIONALINFORMATIONONTOLOGY.
ASUB‐ONTOLOGYFORCOMMUNICATION
Ontologyisadescriptionofastructureandhierarchy
of notions, symbols and objects of the world or it
s
part. The term navigational information ontology is
understood as a meta‐language describing the
structureandformofinformationusedinnavigation,
takingintoaccountinformationtypesandscopes.An
exampleclassification,definitionofsetstructuresand
their interrelations are presented in [4]. The
mentionedmeta‐languageshould alsobecompat
ible
withalreadyadoptedstandardsreferring toselected
areasofnavigationalinformation.
Figure 1. A window of Protége program: fragment of
navigationalcommunicationontology.
The construction of ontology requires that both
terms and relations between them as well as their
attributes should be defined. These are generally
simple variables, storing one concrete value
represented by one of the simple and enumeration
typeofdata.Examplesaresuchtermsastruecourse,
speedorbearingexpressedbynumericalvalues,and
logical va
lues represented by enumeration type of
191
data (e.g. TRUE‐FALSE or TRUE‐FALSE‐
UNKNOWN).
Among others, the following are incorporated in
the developed sub‐ontology for communication
(fragment):
Typesofmessages:
statement(S)
question(Q)
intention(I)
demand(request)(D)
Typesofnavigationalinformation:
CPA(C)
TCPA(TC)
shipʹscourse(G)
portside,toport(L)
st
arboardside,tostarboard(R)
forward,thebow,aheadof(F)
aft,thestern,asternof(K)
...
Othertypesofinformation:
confirmation(acknowledgement)(H)
...
Typesofmanoeuvres:
passing(P),relatedwithLandR
coursea
lteration(T),relatedwithLandR
crossingcourse(E)
...
Abstractterms:
near,about(N)
possible(M)
impossible(W)
safely(O)
dangerous/ly(U)
true(V)
false(X)
...
Objects:
Ship,relatedwithL,R,FandS
...
Writ
ingdownnavigationalinformationaccording
to the adopted ontology necessitates coding it in a
specific formal language, such as XML (eXtensible
Markup Language). This enables automatic
generation, validation and interpretation of XML
messages in data communications systems. For that
purpose the XML Schema can be used, as it can
describethecontentandstructureofXMLdocuments
inXML.
4 ANEXAMPLEOFCOMMUNICATION
The developed ontology of navigational informat
ion
and sub‐ontology for communication allow to
formally write down simple messages as well as a
dialogbetweentwoships(navigators)orbetweena
ship and a land‐ba
sed centre, in which questions,
intentionsandotherlinguisticfunctionscanbetaken
into consideration. To exemplify this, let us take a
look at communication taking place in a very
commonsituation: anencounter of twoships atsea.
We present an automatic exchange of informat
ion
thatcouldsuccessfullycomplement,andinthefuture
partlyorfullyreplaceverbalcommunication.
Two motor‐powered vessels (A, B as objects of
type ship) are on crossing courses. In this situation,
accordingtoCOLREGs,oneshiphastherightofway
(ALPHA)andtheotherisagive‐wayvessel(BRAVO)
(Fig.2).
Figure2.Anexampleofnavigationalsituationinstage1.
Stage 1: When the ships are at approx. 7.5 Nm
fromeachother,theyestablishcontact:
1 ALPHA:CPAis0NmandTCPAis15
2 ALPHA:Passasternofme.
3 BRAVO:OK.,Iwillaltercoursetostarboard.
4 ALPHA:OK.
After a certain time, the distance between ships
decreased to 4,5 Nm (Fig. 3). The give ‐way vessel
(BRAVO) has performed the mentioned manoeuvre
but insufficient
ly – the risk of collision is still
significant. The encounter comes into another stage
andadditionalactionstopreventcollisionisrequired.
Figure3.Anexampleofnavigationalsituationinstage2.
Stage 2: When the distance decreases to 4.5 Nm,
thefollowingmessagesareexchanged:
1 ALPHA:CPAis0.7NmandTCPAis10
2 ALPHA:Altercoursetostarboardtokeep1.0Nm
asternofme.
3 BRAVO: OK., I will alter course15 degrees to
starboard.
4 ALPHA:OK.
Using the ontology of navigational
communication, we can present the ab
ove messages
mathematically (formal notation), that enables
generating and interpreting of messages and their
furtherprocessingincomputersystems:
1 ALPHA:CPAis0NmandTCPAis15
2 WARNING ((CPA(Alpha, Bravo) is 0) and
(TCPA(Alpha, Bravo) is 15))→ W((C(A, B) is 0)
andTC(A,B)is15))
3 ALPHA:Passast
ernofme.
4 DEMAND(CROSS(Bravo,Alpha.Stern)isTRUE)
→F(E(B,A.K)isV)
5 BRAVO:OK.,Iwillaltercoursetostarboard.
6 INTENTION(TURN(Bravo, Starboard) is TRUE)
→I(T(B,R)isV)
192
7 ALPHA:OK.
8 STATEMENT (CONFIRMATION(Alpha) is
TRUE)→S(H(A)isV)
9 ALPHA:CPAis0.7NmandTCPAis10
10 WARNING ((CPA(Alpha, Bravo) is 0.7) and
(TCPA(Alpha,Bravo)is 10))→ W((C(A, B) is 0.7)
andTC(A,B)is10))
11 ALPHA:Altercoursetostarboard
tokeep1.0Nm
asternofme.
12 DEMAND ((TURN(Bravo, Starboard) is TRUE)
and(DISTANCE(Alpha,Bravo)is1.0))→F((T(B,
R)isV)and(D(A,B)is1.0))
13 BRAVO: OK., I will alter course alter course15
degreestostarboard.
14 STATEMENT((Bravo) is TRUE) and
(COURSE(Bravo) isCOURSE(Bravo)+15)) →
S((H(B)isV)and(G(B)is(G(B)+15))
15 ALPHA:OK.
16 STATEMENT(CONFIRMATION(Alpha)isTRUE)
→S(H(A)isV)
Thisform of representing certain procedures and
intentionswillenableusingthemindecisionsupport
systems. In addition, if it is presented in a readable
manner (graphical or digital), it could
be a valuable
supplement to verbal communication, allowing to
avoid ambiguity in expressing intentions and to
formally acknowledge intentions. Additionally in
ordertosuchdialoguehadplacetoappearnavigation
situation must be identify as requiring
communication. based on CPA, TCPA values and
inferencemethods theidentification canbeachieved
[11].
5 NON‐CRISPTERMS
Interpersonal communication in a natural language
makesuseofexpressionswithtermswhoseattributes
assumecrispornon‐crispvalues.Non‐crispvalues,or
precisely, the values of their attributes, may come
directly from a natural language, e.g.ʺnearʺ,ʺfarʺ,
ʺsafelyʺ,ʺdangerouslyʺ,
ʺaboutʺ,ʺsafe distanceʺ,
ʺdangerousdistanceʺ.Intheprocessofnavigation,i.e.
safeshipʹsproceedinginwater areafrompointAto
pointB,suchinformationattributesmaybegenerated
byshipboardequipmentanddetermineshipʹsstatus
as a state of a moving object in relation
to other
mobile or stationary objects. In the decision making
process the navigator‐operator accepts deviations
withintheassumedsafetylimits.Occurrenceofnon‐
crisp values appear ing in a specific communication
between human operators is a significant difficulty
for formal description of such communication. For
navigational communication ontology to offer
its
convenientuseinarealnavigationalenvironment,it
hastodescribebothcrispandnon‐crisp(fuzzy)terms.
Examples of non‐crisp terms can be found inthe
criteria for safety assessment, namely CPA (Closest
Point of Approach)andTCPA (Time to Closest Point of
Approach). This criteria
are commonly used in ship
encounter situations. Taking into account
uncertainties (inaccuracies) in assessing safety is
possiblewhenweuse,e.g.fuzzylogic,thatallowsto
describethesafetylevelwithlinguisticvaluessuchas
usedbyhumans.Thisconsistsinassigninga degree
of membership (x) 0, 1
to crisp values, e.g.
measured distance x. It means that, apart from
membership (1) or no membership (0) – as in the
classical set theory – membership maybe partial. In
caseofCPAitmeansthat,foravalueCPA
Lpresetby
thenavigator,an interval of tolerance is assumed to
exist CPA
Lmin, CPALmax such that
(CPA
LminCPALCPALmax), and any value of CPA is
assigned a degree of membership to the fuzzy set
CPA
LF, described by a membership function
(x) of
thisset(Fig.4)[9].
Figure4MembershipfunctionofafuzzysetfuzzyCPALF.
Similarly for a value TCPAL also preset by the
navigator,anintervaloftoleranceisassumedtoexist
CPA
Lmin, TCPALmax such that
(TCPA
LminCPALCPALmax), and a membership
functionν(x)(ν(x)0,1fordegreeofmembershipto
the fuzzy set TCPA
LF is described by analogous
function.
Thecriteriaofshipdomainandshipfuzzydomain
canbesimilarlyconsidered[8].
Theuseoffuzzylogic,methodsandtoolsoffuzzy
setsinparticular,enablesaformaldescriptionofnon‐
crisp terms, their inclusion in messages and their
interpretation and processing in
computer systems,
e.g.ininference processes.This descriptionrequires,
amongothers,thedefiningofrulesformathematical
notation of a message sent. The basic notation of
message(p)isasfollows:
p
XisR
whereXisavariable, is–sentence‐formingfunctor,
R–relationconstrainingthevariableX.
Dealing with a more extensive message, we can
additionallydefineawiderrangeofvaria bleoriginas
a function and write the message notation in this
form:
p
AX isR
where A is a group in the sub‐ontology to which X
belongs.
In a natural language there are various types of
sentences,e.g.affirmative(statement)orinterrogative
(question). For precise interpretation of message
content we can additionally adopt a function
193
identifyingsentenceform,wherethewhole message
notationisanargumentofthatfunction.
6 SUMMARY
Safenavigationoftendepends oninformationaccess
andcapabilitiesofautomaticexchangeand
interpretation of relevant information. These
requirements are facilitated, among others, by the
standardizationofinformationcontentandform.Fast
advancements in
IT and ICT technologies broaden
possibilities of automating communication processes
sofarexecuted verbally.This,however,necessitates
construction of navigational information ontology,
including a sub‐ontology for communication. The
authorspresent in this article the results of research
on a system of automatic intership communication
and co‐operation. Based on
the developed sub‐
ontology for communication, an example
communication established between two ships in an
encountersituationispresented.Theauthorspropose
to extend information ontology by including non‐
crispterms,typicalofverbalcommunication.
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