Results for area 10.3 Service Interface for Real Time Information (SIRI)
the Address part of Endpoint Reference, specified as (the URI to send a message to) and Endpoint Reference Properties, that identify stateful resources
a Delivery containing only that information which has changed since the last update
a local VEHICLE from one Control Centre that is Roaming into the area managed by another Control Centre
the service requestor’s suggestion for the initial termination time of the Subscription being created, also known informally as ‘Lease Wanted’; this time is an absolute UTC time, timed according to the time source used by the Notification Producer
the span of time within which data of a given type is available
NOTE For stable long term data, this may be the validity period of the timetable or stop data. For more volatile short term data such as daily operational changes, it may be a shorter operation period such as the day or week. For real-time data this will be the retention period in the system of very volatile data, such as short term movement and prediction data, for example an hour, or as soon as the data is obsolete. Systems that keep historic logs of data value may offer a longer data horizon for some types of volatile data.
all activities related to the mid-term and short-term management of drivers
a message or message sequence sent from the Producer to the Consumer to return payload content, either in immediate response to a Request, or sent asynchronously when a Notification Producer determines that the conditions of a Subscription are satisfied
a set of constraints on the nature and volume of data to be returned in the Delivery. A Filter is specified on a Request or a Subscription message. Filters may include both a Topic Expression of content related terms, for example the STOP POINT, JOURNEY or Temporal span, and also a Subscription Policy, containing terms regulating the processing of the subscription, for example the Volume, indicating how many entries should be returned
a visit by a VEHICLE to a specific STOP POINT as it follows the JOURNEY PATTERN of its VEHICLE JOURNEY to achieve a set of planned and estimated PASSING TIMEs
NOTE A VEHICLE may make more than one Call to the same stop in the course of a JOURNEY: different calls may typically be distinguished by a Visit Number count. The Call may have real time data associated with it. A SIRI Call may be regarded as a useful optimisation of a more normalised set of structures that are articulated separately in TransModel. Call combines the TransModel elements of POINT IN JOURNEY PATTERN in with ESTIMATED PASSING TIME, OBSERVED PASSING TIME, & TARGET PASSING TIME, along with real time elements and other stop properties pertaining to the visit.
NOTE That SIRI segregates all elements pertaining to arrival from those pertaining to departure, again facilitating the validation and implementation of actual systems.
a description of a recognized mode of failure, reified in SIRI as a named error. Requests may be refused because of an Error Condition is detected. Different Error conditions are each represented in SIRI as separate elements each with an error code and a recommended error handling procedure.
unique identifier of a SITUATION ELEMENT made up of several parts, the Country Code, Participant Code, Situation Number and Version number
all activities allowing the company management to collect the information necessary to meet problem-solving needs.
NOTE 1 to entry Data of operational systems are filtered and aggregated for this purpose, and made available to the user interactively, or in the form of pre-defined reports and summaries. Such functions are in principle related to all functional areas of a company, with particular reference to the management of statistical results.
describes the conditions and circumstances of monitoring: manual/automatic, frequency of measurement, etc.
a categorisation of the informative messages that is used to filter messages from the message service;
Informative messages have an identifier and version.
for Frequency based services, the interval between vehicles may be TIMETABLED, AIMED, ESTIMATED or ACTUAL
Route Guidance, Map Display, Address Location, Services and POI Information Access, cooperative ITS including
a given ORGANISATIONAL UNIT, using a SIRI Control Centre system, manages its own set of Local VEHICLES and VEHICLE JOURNEYS, for which it is responsible for provisioning and updating the data
an informational message that is exchanged between Participants using a General Message service.
NOTE 1 to entry Informative messages have an identifier and version so they can be updated and revoked. Their content may be in plain text, or structured according to an agreed format. Informative messages may be segregated into separate information channels according to an agreed categorisation, for example , Warning, Advice, etc.
the coordination of inbound feeder and outbound distributor journeys at an interchange so as to maximise the chances of passengers achieving their journeys. Involves the exchange of information between feeder and distributor to inform dispatchers and passengers of the current situation, and the delaying of distributor vehicles so as to honour GUARANTEED CONNECTIONS.
a Subscription Manager is a service that allows a Service requestor to create and manipulate Subscription Resources. A Subscription Manager is subordinate to the Notification Producer and may be implemented by the Notification Producer service, or separately as desired. In SIRI only limited capabilities to manage subscriptions are provided.
a term in a Subscription Policy specifying of the degree of change that is permitted in the values of certain quantitative Topic data elements or other Subscription Policy values before a further update Delivery should be provided by the Server to its Subscribers. Also known as ‘hysteresis’.
the monitoring of the real-time arrivals and departures at an interchange for changes against the planned schedule
the monitoring of the real time status and expected activities of vehicle arrivals and departures at a Stop Monitoring point.
The SIRI Stop Monitoring Service provides information of the real time status and expected activities for one or more MONITORING POINTs, corresponding typically to STOP POINTs.
point at which real-time status is reported, normally corresponding to a STOP POINT
NOTE 1 to entry In IFOPT only a minimal representation of MONITORING POINTs is made sufficient to relate their location to the STOP PLACE and its components.
a point at which real-time status is reported; normally corresponds to a STOP POINT
temporary permission to use a ticket purchased for use of a transport service on a different travel product because the original service has been disrupted
EXAMPLE To use a bus instead of the metro.
a suggested alternative solution for passengers when a facility/service is no longer available
cause of a SITUATION that is not known about in advance
a basic data quality measure used to indicate when the Predicted Times are known or thought to be imprecise
NOTE 1 to entry In some cases the cause of the inaccuracy may be indicated by a more specific reason, for example IN CONGESTION.
the act of transmitting a Notification Message to a Notification Consumer. Notifications are sent from the Publisher to the Producer and then from the Producer to the Consumer. The direct unmediated forwarding of notifications from the Publisher by the Producer without filtering or transformation is termed ‘unbrokered’ notification. SIRI requires the mediation of messages by the Producer.
the number of passengers on a vehicle
an entity that acts as a Service Requestor, sending a Subscription Request on behalf of a Consumer to a Notification Producer. The Consumer entity will usually be the same entity as the Subscriber, but may also be a separate entity.
a SIRI Notification Producer mediates the flow of notifications it processes so as to reduce the amount of data traffic to a subscriber. All SIRI subscriptions for a Subscriber are automatically assigned to a Subscriber Channel. The subscriptions in a channel are mediated collectively; if a Situation affects more than one subscription within a channel, only a single notification is sent to the subscriber. The resulting delivery contains all updates for all subscriptions in the channel. There is at least one subscriber channel per Subscriber; some implementations may allow more than one channel for a given subscriber.
the estimated deviation from the schedule for a VEHICLE JOURNEY, specified in seconds
NOTE 1 to entry In SIRI, positive values are associated with vehicles that are behind their schedule, negative values with ones that are ahead.
the departure of an outgoing distributor VEHICLE JOURNEY from a CONNECTION LINK
the identifier issued to identify an individual request within a conversation, and subsequently used to refer to the request in further exchanges within a stateful resource pattern, such as Publish/Subscribe, or Fetched Delivery
a Delivery from the Server to the Client, returned in response to a Subscription Request; either confirming the creation or other change to a Subscription, or giving an Error Condition
the role of the outgoing VEHICLE from a TARGETED INTERCHANGE, which picks up passengers from a CONNECTION LINK who have transferred from a Feeder Service
NOTE 1 to entry Sometimes also called a Fetcher.
a web service endpoint is a referenceable, entity, or processor resource to which Web Service messages can be targeted. Endpoint references convey the information needed to identify and reference a Web service
NOTE 1 to entry Endpoint references are used to provide addresses for individual messages sent to and from Web Services, both synchronously and asynchronously. An endpoint reference includes an Address (the URI to which to send a message) and also Endpoint Reference Properties, that identify stateful resources, such as subscriptions. They may also indicate a Port and Processing Policies. WS-PubSub and the other web service standards require the separation of the endpoint references from their bindings to a given transport protocol, such as SOAP. In SIRI, each Participant is an endpoint for each of its roles in message exchange, i.e. Subscriber, Producer and Consumer. A Subscription Reference is an Endpoint property and is typically made up of two parts: (i) a Participant Reference, which may be specified in the configuration to indicate the Control Centre, and is not necessarily repeated explicitly on individual messages, and (ii) the Subscription Identifier, which is a serial number for an individual subscription that is unique within the SIRI Functional Service and Participant Reference.
a cause of a SITUATION that is known about in advance; it will have a known start and likely end time. In SIRI-SX this is recorded as an attribute of a general purpose incident description
the period of time for which the information can be used, after which it becomes stale
the discrete visit by a VEHICLE making a call at a STOP POINT in the course of a DATED VEHICLE JOURNEY
NOTE The visit may include an arrival, departure or both, for each of which it may have separate Targeted (aimed), Estimated and Observed (Actual) times.
a means of distinguishing repeated visits to a stop by a vehicle within the same journey pattern. A monotonically increasing number that is unique within a given scheduled stop point for a given journey pattern, as distinct from the TransModel ORDER; a monotonically increasing number that is unique on each call within a given journey pattern (i.e. that provides an overall serial ordering and unique identification of the stop within the whole journey pattern).
a transient data container element included in a SIRI functional service response that has a timestamp; it may optionally have an Item Identifier which can be used to reference it subsequently, for example to associate a cancellation of an earlier item.
the first message of the Fetched Delivery sequence: it informs the Consumer that the Notification Producer Service has updated data that is now ready to fetch using a Data Supply message.
a means of distinguishing repeated visits to a stop by a vehicle within the same JOURNEY PATTERN; a monotonically increasing number that is unique within a given SCHEDULED STOP POINT for a given JOURNEY PATTERN
NOTE 1 to entry When combined with the scheduled STOP POINT Identifier the STOP VISIT COUNT can be used to uniquely identify the position of the vehicle along a JOURNEY PATTERN.
an application mechanism used to specify whether a participant may use Service Capabilities, or access, specific Topic content of a Service
a message from the Subscriber client to the Notification Producer to create a Subscription
NOTE In SIRI a Subscription Request contains one or more SIRI Functional Service Subscription Requests.
a service Subscription Request specifies the specific SIRI Functional Service for which the Subscription Request is made
NOTE SIRI Functional Service Subscription Requests have the form XxxSubscriptionRequest and are always embedded in a Subscription Request.
an entity that sends Notification messages to a Consumer as a result of a previous Subscription made to it for a Functional Service. Events that give rise to Notification messages are sent to the Producer by a Publisher entity.
a Service that implements the distribution of Notification messages to satisfy Subscriptions.
NOTE The Notification Messages themselves are generated by a Publisher (and may be routed to the Notification Producer via a Notification Broker). A Notification Producer maintains a list of Subscription resources and uses the Topic Filters of the individual Subscriptions to match the Notification Messages with the Subscribers’ interests. If it identifies a match, it issues a notification to the Notification Consumer associated with the Subscription.
a two step Delivery in which first a Data Ready message is sent from the Producer service to the Consumer to notify the Consumer that data is ready, and then secondly the Consumer fetches the data by sending a Data Supply request to the Producer Service, which then finally sends a Data Supply Response message with the actual payload
the revised version of the TIMETABLE for a Service containing updates to the original published timetable
NOTE The original TIMETABLED TIMES are referred to as TARGET TIMES.
record of a change to a particular SITUATION, originally established by a BASE SITUATION ELEMENT
original record of a particular SITUATION
NOTE This may subsequently be followed by UPDATE SITUATION ELEMENTS that record further changes.
the time needed to go from stop point to stop point across a CONNECTION LINK
the process of preparing and equipping a network so that it can provide (new) services to its users
NOTE In NS/EP telecommunications services, “provisioning” equates to “initiation” and includes altering the state of an existing priority service or capability. the populating of a system with a complete set of stable data necessary for its operation, both reference data and content; for example, the stop identifiers and the timetable data for an AVMS system.
NOTE Provisioning is distinct from Configuration – the setting up of the systems’ operational parameters and other variable features – in that it may be routinely repeated from time to time when a new data set is prepared.
a categorisation used in data presentations to indicate that the vehicle has been classified as Early against some criteria. The status of Early will be derived from the real-time progress data. This term should be contrasted with SCHEDULE DEVIATION which specifies the deviation from schedule in seconds.
classification of a SITUATION ELEMENT as being of a particular type
NOTE The nature of the REASON is likely to have implications for the duration and consequence of the SITUATION.
the arrival of an incoming feeder VEHICLE JOURNEY to a CONNECTION LINK
a change to the planned arrival to, or departure from, a connection link for a vehicle journey that is material to passengers intending to make a planned interchange
EXAMPLE Events may include a delayed arrival of the feeder, a decision to prolong the wait by the distributor vehicle, a change of the distributor departure point, or cancellation of either of the feeder or distributor journeys.
the role of the incoming VEHICLE to and VEHICLE JOURNEY at a TARGETED INTERCHANGE, which feeds passengers to an arrival STOP POINT having a CONNECTION LINK to a departure STOP POINT from where they will board a Distributor Service. A VEHICLE may perform both feeder and distributor roles at the same time, that is, both set down passengers to transfer to other services, and board passengers from other services.
a Participant Reference i.e. identifier of a Participant acting as a Subscriber: provides a unique scope for the Message Reference
a Publisher Registration represents the relationship between a Publisher and a Notification Broker, an optional WS-PubSub intermediary that can be introduced to delegate the distribution of Notification Messages to one or more distinct entities that act as Notification Producers
the movement of a VEHICLE through the area managed by a different Control Centre; within its home Control Centre the vehicle is Local; in other Control Centres it is Foreign
the identifier issued to identify a Subscription, and subsequently used to refer to it in further exchanges within the Publish/Subscribe stateful resource pattern
NOTE In SIRI, the Subscription Reference comprises two parts: the Subscriber Reference (i.e. the Participant Code of the subscriber), and the Subscription Identifier: unique within the scope of a Participant Reference. Subscriber References are issued by a Subscriber in SIRI, not the Producer. Formally in WS-PubSub, a subscription reference is a WS resource returned in a Subscription Response containing the address of the Subscription Manager, and the Subscription Identifier. In SIRI the address of the Subscription Manager is obtained indirectly.
unique identifier of a Control Centre or other type of Service Participant
NOTE The reference is bilaterally agreed between participating systems, and will typically be unique for a region of a country within which systems need to communicate. The Participant Reference is used to scope other data identifiers within each bilateral date reference agreement.
scope of a SITUATION ELEMENT or consequence of a SITUATION ELEMENT in terms of the specific entities such as OPERATORs, NETWORKs, LINEs, SCHEDULED STOP POINTS, STOP PLACES, PLACEs, etc that are affected
an ORGANISATIONAL UNIT that manages a network or networks of vehicles and their attendant real-time systems, and corresponding specifically to a SIRI Service Participant
NOTE Each Control Centre has a uniquely identifier, (the Control Centre Code), which provides a scope (i.e. unique namespace) for all non-global data references, such as stop identifiers, vehicle identifiers, etc. Within a Control centre, references must be unique. VEHICLES and JOURNEYS within the span of control of a given Control Centre are Local; VEHICLES and JOURNEYS within the span of control of an external Control Centre are Foreign.
a coherent named set of features that a SIRI Functional Service may implement to provide particular application functionality
NOTE Some capabilities are common to all services; others are specific to individual functional services. Each SIRI functional service has a number of required capabilities, a number of capabilities for which alternatives are allowed, and a number of optional capabilities. A Capability Matrix is used both to specify the named capabilities for each SIRI functional service, and for the capabilities common to all SIRI functional services.
some occurrence within a service or its environment of interest to third parties
NOTE A Situation can be a change of state in the service itself, or an event in the context of the systems it monitors. A Publisher that detects a Situation will create a Notification Message.
identifiable occurrence in the real world comprising one traffic/travel circumstance which has its own life-cycle
NOTE 1 to entry Details of each situation element are mapped into a single data record.
set of traffic/travel circumstances linked by a causal relationship which apply to a common set of locations
NOTE 1 to entry A situation can be composed of situation elements.
NOTE 2 to entry SITUATION is not a Transmodel term, but is used in Trident and SIRI as a generic term for incidents and planned disruptions.
NOTE 3 to entry In IFOPT the STOP PLACE model provides a precise location model for specifying the scope of an incident and may be referenced by other services such as SIRI.
a request that contains more than one request for a concrete SIRI Functional Service within it: each concrete request specifies a different topic
NOTE Similarly a compound subscription contains more than one SIRI Functional Service subscription request.
particular mode of being of a facility; describing its state and availability
a concept used by a Notification Producer to categorise Notification Messages to decide which Subscribers should be sent a Notification
NOTE 1 to entry A Subscriber specifies which Topics it is interested in as part of its Subscription Request.
the allowed duration of a Subscription
NOTE In SIRI, leases are specified by an Initial Termination Time and cannot be negotiated or renewed.
a Request from the Client to the Server to close a Subscription
an entity that receives Notification messages from a Producer as a result of a previous Subscription made to a Service
NOTE In SIRI, in order to manage recovery, a Consumer must know the Subscriber which asked for its subscriptions.
a Client that receives Notification Messages from a Notification Producer
NOTE The role may be performed by the same or a different entity as that of the Subscriber who created the Subscription which requested the sending of the Notification Messages in the first place.
a system that participates in the exchange of messages using the SIRI protocols
NOTE A Participant has a Participant Reference, used to identify the participant in message exchanges, and also used to provide a general purpose namespace to scope arbitrary identifiers of model elements such as line and vehicle identifiers. In SIRI Consumers and Notification Producers (i.e. Control Centres) are Participants.
a SIRI Service Participant is a participating system that exchanges SIRI messages with another Service Participant
NOTE Each Service Participant has a unique identifier, (the Participant Code), which provides a scope (i.e. unique namespace) for all non-global data references, such as stop identifiers, vehicle identifiers, and also for message identifiers of requests and subscriptions. Service Participants will either be SIRI Functional Service systems providing information, or accredited client systems that send request and subscriptions to the services to obtain information.
an entity that processes events in the data feeds and sends Notification messages to a Producer for brokering and distribution to Consumers
NOTE The Producer may carry out additional mediation such as filtering or data transformation. The use of a Notification Producer is transparent in SIRI.
the act of removing a Stop Visit from a DISPLAY once a vehicle has arrived at a stop
NOTE For improved latency, ‘Direct Cleardown’ may often be done by direct wireless communication between the approaching vehicle and the stop display equipment, as well as by the regular back-end communication between the Stop Monitoring producer server and the Stop Monitoring Consumer entity of the client system driving the stop display.
A separate Cleardown identifier may be associated with each Stop Visit for this purpose, which can be used to reconcile the previous Stop Visit with the arriving vehicle; typically this will be a short numeric code designed to be efficient for communication over a radio channel of restricted capacity.
a strategy to bring a vehicle back onto schedule by curtailing the end of one VEHICLE JOURNEY and the start of another
NOTE 1 to entry Short Working is a type of CHANGE IN JOURNEY PATTERN.
a categorisation of a VEHICLE JOURNEY for presentation as being late and subject to significant uncertainty caused either by a Disturbance to the transport network or a problem with the VEHICLE itself
a pattern of interaction between a Client (as Subscriber and Consumer) and Server (as Notification Producer) involving the sending of an initial Subscription and the subsequent asynchronous receipt of one or more Notification Messages that contain a payload of information. The Subscription has a Lease, which defines it duration.
a resource such as a Subscription that is used to support a stateful pattern of interaction must have certain characteristics, such as an endpoint reference, with which Consumer and Notification Producer can agree to refer to the resource, and an address to which notification message can be sent
NOTE 1 to entry WS-PubSub indicates what these characteristics and equivalent elements are present in SIRI: note however that for some SIRI implementations, some resource properties may be specified statically in the configuration, rather than being specified dynamically on each individual message.
a separate intermediary entity that may be used to distribute the Notification Messages produced by a Publisher entity to one or more Notification Producer services
NOTE 1 to entry This allows the decoupling of Publisher and Producer roles if desired. A Notification Broker may also provide specific services such as Access Control.
part of SITUATION ELEMENT content that contains guidance as to how the SITUATION should be disseminated
a release level assigned to a coherent set of software artefacts, such as an interface
NOTE In SIRI there are two version levels – the overall version level for the general services, and the version level for each individual SIRI functional service. The latter functional service level may be used as a single version identifier.