L. Sabatucci, P. Ribino, C. Lodato, S. Lopes, and M. Cossentino GoalSPEC: a Goal Specification Language supporting Adaptivity and Evolution L. Sabatucci, P. Ribino, C. Lodato, S. Lopes, and M. Cossentino

Outline Motivation The Proposed Approach A Goal Specification Language: GoalSPEC Examples EMAS'13 - GoalSPEC - M. Cossentino

Motivation Introducing adaptation in workflow designed using BPMN Conventional (rigid) workflow does not satisfy the needs in many scenarios What changes Scenarios change continously Way people work changes People change Workload is often unpredictable What is constant Skills The business analysist knows BPMN and does not want to study a new language/paradigm (agents) Each worker is able to perform some duties and not some others EMAS'13 - GoalSPEC - M. Cossentino

The Proposed Approach EMAS'13 - GoalSPEC - M. Cossentino

The proposed approach Focussing on goals pursued by the workflow The workflow specification in BPMN has to be translated into a goal oriented specification Assumptions: Each workflow pursues a goal Each task in the workflow pursues a subgoal of the workflow goal Letting agents find the best way to achieve goals when changes occur Agents are someway generic They have some capacities the knowledge they can achieve some state of the world by using capacity implementations available in the execution environment They are able to access and control available implementations of their capacities They commit to goal of the workflow (that means they carry on related tasks) if the goal outcome correspond to the state of the world achieved by one of the capacities owned by the agent EMAS'13 - GoalSPEC - M. Cossentino

Self-Adapting Workflows: our Receipt Distributed system with decentralized control Software Agents able to reason on the expected behavior aware of their capacities and consequences dynamic commitment to system goals Business Goals and Rules may be injected into the system at run-time The system (re-)organizes itself according to the published business goals For these aims, we NEED a goal specification language EMAS'13 - GoalSPEC - M. Cossentino

Impact: Revisiting the lifecycle of Business Process Evolution models revises Business Analyst Business Expert GoalSPEC automatic translates into worker injection injection interacts commits to analyzes analyzes commits to analyzes analyzes Running MAS EMAS'13 - GoalSPEC - M. Cossentino

The Adopted Agent Architecture Goal 2 Goal 3 Goal 1 Goal n GOALS (design time and runtime) Agent1 Agent2 Agent2 Agents (GUI) (GUI) Resources (databases, …) Business Analyst Web Service Workflow User Web Service Environment

GoalSPEC

GoalSPEC Many Human-Oriented Languages exist to specify Goals (i*, Tropos, Kaos) Responding to the need for “modeling” goals at design time KAOS may also support runtime interpretation of goals but it is too complex for non-skilled workflow analysts GoalSPEC is a communication language between humans and agents: Can be automatically generated from a BPMN workflow representation But also manually revised by business experts It can be automatically interpreted by Software Agents EMAS'13 - GoalSPEC - M. Cossentino

Key Features of GoalSPEC It allows to express functional requirements It is grounded on an ontological description of the problem domain Ontology elements are used to specify the expected results of a goal It allows to introduce points of flexibility in the specification of goals EMAS'13 - GoalSPEC - M. Cossentino

Anatomy of a Goal in GoalSPEC The goal specification sentence in GoalSPEC: WHEN <something happens> <actor> SHALL ADDRESS <a desired state> When: Triggering Condition Who: the actor e.g. The System, agentA,… What: Desired State GoalSPEC considers two categories of actors: The SYSTEM considered as a whole (the goal will be pursued by an agent or a group of agents) Human ROLES that participate to the workflow EMAS'13 - GoalSPEC - M. Cossentino

This Goal is assigned to the software system WHEN <something happens> THE SYSTEM SHALL ADDRESS <a desired state> This Goal is assigned to the software system The clause ‘WHEN <something happens>’ requires the candidate agent will activate some perceptions The clause ‘ADDRESS <a desired state>’ requires the candidate agent will (generally speaking) need both actuators and monitors (perception capabilities) The Actuator to achieve the desired state The Monitor to check if actuator has been successful Otherwise, when a goal is assigned to a human role, system is only responsible for: Interacting with the human to verify goal satisfaction or Autonomously monitoring satisfaction EMAS'13 - GoalSPEC - M. Cossentino

The agent can commit to a specific goal only if WHEN available(document) THE SYSTEM SHALL ADDRESS classified(document,Category) We use descriptive logics for triggering conditions and desired states. The agent can commit to a specific goal only if It owns a capacity to check if the belief is true: “is available(document) true?” It owns the capacity to lead the world to the desired state: “classified(document,Category)” where Category is grounded (for instance Category==invoice) EMAS'13 - GoalSPEC - M. Cossentino

Work in Progress: Degrees of freedom Adaptation demands some degree of freedom Agents can exploit this degree of freedom in their decision process, according to the current context they are facing GoalSPEC proposes FUZZY modifiers to relax requirements constraints WHEN available(document) THE SYSTEM SHALL ADDRESS classified(document,Category) AS SOON AS POSSIBLE WHEN cassified(document,invoice) and delay(document,Delay) and Delay IS CLOSE TO 1 week THE SYSTEM SHALL ADDRESS *In place of “IS CLOSE TO 1 week” it is also possible to use “AFTER/BEFORE 1 week” EMAS'13 - GoalSPEC - M. Cossentino

Examples

Example: BPMN NOTE LUCA: BPMN è una notazione grafica per la definizione di flussi di lavoro. OMG ha definito un meta-modello per la sintassi del linguaggio e di conseguenza uno schema XML per la rappresentazione sia del modello che dei dettagli grafici. In questo esempio abbiamo TASK (in verde e contrassegnati da uno stereotipo grafico: busta bianca = task per la ricezione di messaggi, Busta nera = task per l’invio di messaggi, ingranaggi = task per attivare un Service, tabella = task che segue delle regole definite dall’utente omino = task eseguito manualmente Poi ci sono i DATAOBJECT (con il simbolo del documento, che rappresentano oggetti con uno stato messo tra parentesi quadre) EMAS'13 - GoalSPEC - M. Cossentino

BPMN  XML  GoalSPEC <serviceTask completionQuantity="1" id="_9” name="Classify”> <incoming>_10</incoming> <outgoing>_17</outgoing> <ioSpecification> <dataInput id="Din_9_7" isCollection="false"/> <dataOutput id="Dout_9_12" isCollection="false"/> <inputSet> <dataInputRefs>Din_9_7</dataInputRefs> </inputSet> <outputSet> <dataOutputRefs>Dout_9_12</dataOutputRefs> </outputSet> </ioSpecification> <dataInputAssociation id="_14"> <sourceRef>_7</sourceRef> <targetRef>Din_9_7</targetRef> </dataInputAssociation> <dataOutputAssociation id="_4"> <sourceRef>Dout_9_12</sourceRef> <targetRef>_12</targetRef> </dataOutputAssociation> </serviceTask> La porzione di XML riportata mostra la descrizione di un TASK <incoming> e <outcoming> contengono un riferimento ai “sequence-flow” (freccie) in ingresso e in uscita <ioSpecificaion> eplicita i dati che vengono consumati e prodotti dal task <dataInputAssociation> definisce quali DATAOBJECT sono associati al task WHEN received(Doc) and WHEN unclassified(Doc) THE SYSTEM SHALL ADDRESS classified(Doc) EMAS'13 - GoalSPEC - M. Cossentino

A more sophisticated example WHEN refined(Doc) THE SYSTEM SHALL ADDRESS ( accepted(Doc) and approved(Doc) ) or rejected(Doc) or incomplete(Doc) EMAS'13 - GoalSPEC - M. Cossentino

Conclusions GoalSPEC supports adaptation GoalSPEC supports evolution GoalSPEC syntax aims at increasing the agent freedom of degree in choosing how/when to address the desired state GOALs defines only the desired state, it is up to the agent intelligence to find the best plan to achieve the desired state, according to the current execution context GoalSPEC supports evolution GOALs are defined at design time but also at run-time and then injected into the system agents will change their behavior according to the current set of available goals This mechanism makes the whole system highly configurable and able to follow evolving users’ needs. EMAS'13 - GoalSPEC - M. Cossentino

Thanks for your attention Any question? cossentino@pa.icar.cnr.it