Based on the scope of the definition in Section 3, the methontology methodology was selected for the implementation and evaluation of the ontology of flight safety messages. In addition, the IPS-based aviation network standard and the methontology methodology were applied for the engineering of the ontology of flight messages. The Protégé software was also used to implement the ontology. The system was tested based on the actual data of Mashhad Airport, which were obtained from the outbound and inbound flights of the airport, collected through the radar system and FDS, and finally normalized. By conducting a case study on several flight data samples, we demonstrated the implementation of the flight message ontology, the development of which as an application based on the ATN aviation network could lead to its exploitation. In the present study, the ontology engineering was based on a top-down approach to ontology construction (methodology), the main stages of which included:
- Building a glossary of terms;
- Unification of the concepts;
- Building a concept classification;
- Diagram of the binary relations between the concepts
In practice, ontology development encompasses the following steps:
- Defining the classes in the ontology
- Arrangement of the classes in a hierarchy of 'parent-child classes'
- Defining the features and describing the values that are allowed to be possessed by the features;
- Determining the values of the features for the class samples
5.1. Flight Information Messages
According to the ICAO documents, the flight information messages included:
- Messages containing aviation traffic information;
- Messages containing meteorological data;
- Messages containing the performance status of the aviation equipment;
- Messages containing information on the flight safety messages;
- Messages containing the airline messages
5.2 Types of Flight Safety Messages
Safety messages include the flight plan, departure and arrival messages, flight delays, changes in the flight plan, cancelations, and flight return.
Table 1. Various Types of Flight Safety Messages
Message type designator
|
Message type
|
Message category
|
ALR
RCF
|
Alerting Radio communication failure
|
Emergency
|
FPL
CHG
CNL
DLA
DEP
ARR
|
Filed flight plan
Modification
Cancellation Delay
Departure
Arrival
|
Filed flight plan and associated update
|
CPL
EST
CDN
ACP
LAM
|
Current flight plan Estimate Coordination Acceptance Logical acknowledgement
|
Coordination
|
RQP
RQS
SPL
|
Request flight plan Request supplementary flight plan Supplementary flight plan
|
Supplementary
|
5.2.1 Flight Plan Message
A flight plan includes the details of flight operations. The plan should be presented to the flight plan acceptance unit within a minimum of one hour and maximum of 24 hours before the flight. The flight should occur up to one hour after the time announced in the flight plan. Otherwise, the flight plan would be canceled and should be presented again. Figure 4 depicts a flight plan filled as a hypothetical flight.
5.2.2 Departure Message
A departure message announces the departure time of the flight from the airport of origin to the destination airport.
5.2.3 Arrival Message
An arrival message announces the arrival time of the airplane at the airport.
5.2.4 Delay Message
The pilot or their representative is allowed to announce a delay of up to 15 minutes after the flight time is specified in the flight plan.
5.2.5 Change Message
The pilot or their representative is allowed to announce a change in the type of the airplane up to 15 minutes after the time has been specified in the flight plan. The goal of this message is to inform the relevant units about the change that is to be expected in the primary flight plan.
5.2.6 Cancelation Message
The purpose of a cancelation message is to inform the relevant units about the cancellation of the flight.
5.2 Glossary of Terms
The glossary of terms was formed based on the terms existing in the thesaurus. In the current research, these terms were extracted and selected by the subject matter experts from various sources in each field.
Table 2. Example of Glossary of Terms and Concepts
type
|
Description
|
Acronyms
|
synonyms
|
name
|
concept
|
A telecommunication service between specified fixed points provided primarily for the safety of air navigation and for the regular, efficient and economical operation of air services (ICAO Doc 4444).
|
AFS
|
-
|
Aeronautical Fixed Service
|
concept
|
A gateway via the internet into the Aeronautical Fixed
Telecommunications Network (AFTN) and allows pilots or small airfields access to file their own flight plans and other flight related messages
(UK AIP).
|
AFPEx
|
-
|
Assisted Flight Plan Exchange Service
|
concept
|
A publication issued by or with the authority of a State and containing aeronautical information of a lasting character essential to air navigation
(ICAO Doc 4444).
|
AIP
|
-
|
The Aeronautical
Information Publication
|
concept
|
An aircraft system based on secondary surveillance radar (SSR) transponder signals which operates independently of ground-based equipment to provide advice to the pilot on potential conflicting aircraft
that are equipped with SSR transponders (ICAO Doc 4444).
|
ACAS
|
-
|
Airborne Collision
Avoidance System
|
concept
|
A service established with the objective of contributing to a safe, orderly and expeditious flow of air traffic by ensuring that ATC capacity is utilized to the maximum extent possible, and that the traffic volume is
compatible with the capacities declared by the appropriate ATS authority(UK AIP).
|
ATFM
|
-
|
Air Traffic Flow
Management
|
concept
|
The flight plan, including changes, if any, brought about by subsequent clearances (ICAO Annex 2 / ICAO Doc 4444).
|
CPL
|
-
|
Current flight plan
|
concept
|
The estimated time required to proceed from one significant point to another (ICAO Doc 4444).
|
EET
|
-
|
Estimated Elapsed Time
|
concept
|
A world-wide system of
aeronautical fixed circuits provided, as part of the
aeronautical fixed service, for the exchange of messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics.
|
AFTN
|
-
|
AERONAUTICAL FIXED TELECOMMUNICATION NETWORK
|
Instance
Attribute
|
A time record when an aircraft take off from and airport
|
-
|
-
|
Departure Time
|
concept
|
Maximum of passenger that load in an aircraft
|
-
|
-
|
Aircraft passenger capacity
|
Instance
Attribute
|
Name of airline in IATA book
|
-
|
-
|
Company Name
|
Instance
Attribute
|
Time for DLA register after file in fpl
|
-
|
-
|
Delay Time
|
concept
|
The flight plan as filed with an ATS unit by
the pilot or a designated representative, without any subsequent changes
|
FPL
|
|
Flight plan
|
concept
|
The DLAY message as filed with an ATS unit by the pilot or a designated representative, for delay time of flight
|
DLA
|
|
DLAY
|
concept
|
A defined area on land or water (including any
buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface
movement of aircraft.
|
AP
|
|
AIRPORT
|
Instance
Attribute
|
Aircraft category that fill in flight plan
|
|
|
Type of Flights
|
Relation
|
Flight arrival in airport that is fill in flight plan as arrival airport
|
|
|
Is Arrival airport of
|
Relation
|
Flight departure from airport that is fill in flight plan as departure airport
|
|
|
Is Departure airport of
|
Relation
|
A flight plan is filled for a flight
|
|
|
Fill flight plan
|
Relation
|
A flight plan is cancel of a flight
|
|
|
Cancel flight plan
|
5.4 Classification of Concepts with a Taxonomic Structure
The classification of the concepts was based on the conceptual system in thesauruses. In the present study, each reference term was intended as a concept or class, and the relationships (general/specific) were converted into relationships (subclass/class) using taxonomy or the graph theory in the four sections of subclass, disjoint, exhaustive, and partition.
5.5 Diagrams of Single-function Binary Connection Diagrams
Taxonomic diagrams were formed in the previous step to classify the concepts. Afterwards, the established diagrams were evaluated and determined as a goal in the stages of the conceptualization of forming the single-function binary connection diagrams.
5.6 Table of Dictionary of Concepts, Examples, Relationships, and Features
Table 3 shows the concepts used in the scope of the ontology, along with the relationships, examples, and characteristics of the examples
Table 3. Dictionary of Concepts, Examples, Relationships, and Features
Concept Name
|
Class Attribute
|
Instance Attribute
|
Relation
|
Iran Air 461
|
-
|
-
|
Same Flight as
|
Iran Air Flight
|
Company Name
|
-
|
-
|
Zagross Airlines Flight
|
Company Name
|
-
|
-
|
Airport
|
-
|
Name
|
Is Arrival airport of
Is Departure airport of
|
Flight Plan
|
-
|
Arrival Airport
Company Name
Departure Airport
Type of Flights
Time of Flights
Alternative Airport
|
Arrival airport
Departure airport
|
Delay
|
-
|
Arrival Airport
Company Name
Departure Airport
Delay Time
|
Arrival airport
Departure airport
|
Change
|
-
|
Arrival Airport
Company Name
Departure Airport
Type of Flights
Time of Flights
|
Arrival airport
Departure airport
|
Iranian Airports
|
-
|
-
|
-
|
5.7 Table of Single-responsibility Binary Relations
Table 4 shows the single-responsibility binary relations defined in the dictionary of the concepts. The generation of the table required the explanation of each single-responsibility binary relation in detail, such as the degree of influence, inverse relations, and the mathematical properties.
Table 4. Single-responsibility Binary Relations
Source Concept
|
Relation Name
|
Source card(max)
|
Target Concept
|
Mathematical Property
|
Inverse Relation
|
Flight
|
Arrival airport
|
1
|
Airport
|
-
|
Is Arrival airport of
|
Flight
|
Departure airport
|
1
|
Airport
|
-
|
Is Departure airport of
|
Flight
|
Same Flight as
|
N
|
Flight
|
Symmetrical Transitive
|
-
|
5.8 Table of Class Features
Contrary to the sample properties, which described the concept samples and received their values in the samples, Table 5 describes the properties of the concept classes and defines the corresponding values in the classes. Class features are inherited by subclasses. For each class feature, the ontology developer should fill the related fields with information on the name of the concept in which the feature is defined, type of the value, value, unit of measurement, value accuracy (in case of numerical values), ability, and sample features, the values of which could be evaluated based on the value of the class feature.
Table 5. Table of Class Features
Attribute Name
|
Defined at Concept
|
Value Type
|
Measurement Unit
|
precision
|
Cardinality
|
Value
|
company Name
|
Iran Air
|
String
|
-
|
-
|
(1,1)
|
IRA
|
company Name
|
Zagross Airline
|
String
|
-
|
-
|
(1,1)
|
TBZ
|
company Name
|
Mahan Airlines
|
String
|
-
|
-
|
(1,1)
|
IRM
|
Degree of seat
|
First Class
|
Integer
|
percent
|
1
|
(1,1)
|
100
|
Degree of seat
|
Economy Class
|
Integer
|
Percent
|
1
|
(1,1)
|
60
|
Degree of seat
|
Queen Class
|
Integer
|
Percent
|
1
|
(1,1)
|
75
|
5.9 Formal Rules Table (Inferred)
For this stage, the ontology developer should identify and accurately describe the formal rules required for the desired ontology; there are inferred formal rules for each definition. The methontology process should assist the information on name as an explanation for NL, which includes a logical term that officially describes the term using primary instructions, logic, concepts, features, the single-responsibility relationships that refer to its meaning, and the used variables.
Table 6. Formal Rules (inferred)
Axiom Name
|
Domestic Flight
|
Description
|
Every Domestic Flight that Departed From a Iranian Location must Arrival at another Iranian Location
|
Expression
|
For all (?x,?y,?z) ([Domestic Flight] (?x) and [Departure Place] (?x , ?y) and [arrival Place] (?x,?z) and [Iranian Location ] (?y) -> [Iranian Location ] (?z))
|
Concept
|
Domestic Flights
Iranian Location
|
Refer Attribute
|
|
Ad hoc binary relation
|
Departure Airport
Arrival Airport
|
Variables
|
?x ?y ?z
|
5.10 Table of the Definition of Rules
Similar to the previous section, the ontology developer had to determine and describe the required rules for the ontology based on the table of rules. For each rule definition, the methontology considers the items such as the name, NL explanation, formal description of the rule, concepts, traits, and relations for the table, which are referred to, as well as the variables used in the ruling term. The following specific format is used by methontology to draw the rules:
If <conditions> then <consequent>
In the model above, the left side of the phrases includes the rules and conditions, and the right side of the rule includes the adopted arrangements
Table 7. Applied Rules
Rule Name
|
Separation for Arrival Aircraft
|
Description
|
All Medium aircrafts behind Heavy aircraft shall be Apply 2 minutes minima separation to behind aircraft
|
Expression
|
If [ Medium aircrafts ] (?x) behind [Heavy aircraft] (?y) then [minima separation ] is 2 minutes
|
Concept
|
Medium aircraft
Heavy aircraft
|
Refer Attribute
|
Aircraft Type
|
Ad hoc binary relation
|
Sequence
|
Variables
|
?x
?y
|
5.11 Description of the Samples
The ontology developer may define the related samples that emerge in the concept dictionary in a sample table in order to define the samples when a special ontology model is generated. For each sample, the ontology developer should define the name, which is a conceptual title belonging to the feature values of the name. Table 8 shows an example of flight TBZ5699 on Mashhad-Tehran route, which was expressed for its FPL message and CNL message.
FPL Message:
FF OIFMZTZX OIIIZAZA OIIIZAZX OIIIZTZX OIIXZQZX OIIXZRZX OIMMZAZA
OIMMZPZX OIMMZTZX OISSZTZX
301838OIMMZPZX
(FPL-TBZ5699-IS
-MD83/M-SDFGHIRWXY/S
-OIMM1200
-N0442F320 ORDOB1C ORDOB A647 SBZ/N0442F320 A647 MUXOR MUXOR1V
-OIII0120 OIFM OISS
-PBN/B2B3B4 DOF/180131 REG/URCQC PER/C )
Supplementary:
-E/0249 P/TBN R/EV S/M J/F
A/W AND R STRIP WITH COMPANY LOGO ON THE TAIL C/AMID)
Cancel Message:
311105OIMMZPZX
(CNL-TBZ5699-OIMM1200-OIII-DOF/180131)
Table 8. FPL and CNL Example for TBZ5699 flight
