Semantically-aided Data-aware Service Workflow Composition

Špindlerův Mlýn, Czech Republic, 24. - 30.1. 2009Špindlerův Mlýn, Czech Republic, 24. - 30.1. 2009SOFSEM 2009SOFSEM 2009 11

Semantically-aided Semantically-aided Data-aware Data-aware

Service Workflow Service Workflow CompositionComposition

Ondrej Habala, Marek ParaliOndrej Habala, Marek Paraličč, ,

Viera RozinajovViera Rozinajováá, Peter Bartalos, Peter Bartalos

[email protected]@tuke.sk

Technical University of Košice, SlovakiaTechnical University of Košice, Slovakia

mailto:[email protected]


ContentContent

Introduction - Semantics and Web servicesIntroduction - Semantics and Web services MotivationMotivation for the SEMCO-WSfor the SEMCO-WS Architecture of the system for semantic Architecture of the system for semantic

composition of servicescomposition of services Ontologies for Automatic Workflow Ontologies for Automatic Workflow

ManagementManagement Support of Collaboration in the SEMCO-WS Support of Collaboration in the SEMCO-WS

Environment Environment Design of the process of automated data reuse - Design of the process of automated data reuse -

Workflow Composition and Execution ModuleWorkflow Composition and Execution Module Conclusion and Future WorkConclusion and Future Work


IntroductionIntroduction

Semantic Web Services (SWS) – extension of Semantic Web Services (SWS) – extension of Web Service technologies with semantics in Web Service technologies with semantics in order to automate tasks common when using order to automate tasks common when using WSWS

Tasks: publishing, discovery, selection, Tasks: publishing, discovery, selection, composition, invocation, deployment and composition, invocation, deployment and ontology managementontology management

SWS frameworks combine semantic description SWS frameworks combine semantic description of WS capabilities, input, outputs and behavior of WS capabilities, input, outputs and behavior with the syntactic description in WSDL and with the syntactic description in WSDL and XML-SchemaXML-Schema


Semantics and Web ServicesSemantics and Web Services

Functional Semantics - Functional Semantics - supposing that the supposing that the functionality of a WS is fully described by its inputs and functionality of a WS is fully described by its inputs and outputs, we can apply matching algorithmsoutputs, we can apply matching algorithms

Data Semantics – Data Semantics – can overcome restrictions of the can overcome restrictions of the syntactical and structural description about datasyntactical and structural description about data

QoS Semantics - QoS Semantics - after discovering according to the after discovering according to the requirements potentially applicable servicerequirements potentially applicable servicess, the selection , the selection of most suitable service is neededof most suitable service is needed

Execution Semantics - Execution Semantics - involves e.g. flow of actions, involves e.g. flow of actions, communication patterns, message sequence, communication patterns, message sequence, preconditions and effects of WS invocationspreconditions and effects of WS invocations

Domain Semantics - Domain Semantics - healthcare, bio-informatics, healthcare, bio-informatics, telecommunications, military, school administrationtelecommunications, military, school administration


MotivationMotivation

Meteorological and hydrological experimentsMeteorological and hydrological experiments Lot of data is reused in several experimentsLot of data is reused in several experiments

Semantic Composition of Web and Grid Services Semantic Composition of Web and Grid Services (SEMCO-WS) – tries to deal also with the “what” (SEMCO-WS) – tries to deal also with the “what” of automated workflow compositionof automated workflow composition

New environmental risk management application New environmental risk management application Knowledge Based Workflow System for Grid Knowledge Based Workflow System for Grid

Applications (K-Wf Grid)Applications (K-Wf Grid) Successful, but not everything it was hoped to achieveSuccessful, but not everything it was hoped to achieve

Simplified workflow constructionSimplified workflow construction Interesting problemInteresting problem


Architecture of SEMCO-WSArchitecture of SEMCO-WS


Ontologies for Automatic Ontologies for Automatic Workflow ManagementWorkflow Management

Aims for using an ontology:Aims for using an ontology: better data organization by adding additional metadata better data organization by adding additional metadata

describing semantics of the data available in the system describing semantics of the data available in the system (for describing IOPE),(for describing IOPE),

to conceptualize the domain and provide a vocabulary of to conceptualize the domain and provide a vocabulary of terms occurring in it (user communication and terms occurring in it (user communication and collaboration),collaboration),

ontology capturontology captureses the domain of risk management the domain of risk management and related areas (concepts from geography, and related areas (concepts from geography, meteorology, natural disasters and risk meteorology, natural disasters and risk management),management),

user model that contains information about the user model that contains information about the user's knowledge and relation to the domain user's knowledge and relation to the domain entities.entities.


Ontologies for Automatic Ontologies for Automatic Workflow Management (2)Workflow Management (2)


Support of CollaborationSupport of Collaboration

our aim is to provide knowledge-based our aim is to provide knowledge-based collaboration toolcollaboration tool

first we designed the communication tool first we designed the communication tool facilitating the users to communicate in standard facilitating the users to communicate in standard waysways

then we augmented the tool utilizing the semantic then we augmented the tool utilizing the semantic information incorporated in ontology - the main information incorporated in ontology - the main aspects:aspects: processing on-line discussionprocessing on-line discussion dividing the discussion according to given criteria into the unitsdividing the discussion according to given criteria into the units getting the areas of interest that were discussedgetting the areas of interest that were discussed according to these areas of interest offering the previousaccording to these areas of interest offering the previous

discussions to the given topic or providing other relevant discussions to the given topic or providing other relevant documentsdocuments


Workflow Composition and Workflow Composition and Execution ModuleExecution Module

Petri net model for the workflow description,Petri net model for the workflow description, Abstract Workflow Composition Tool (AWCT) is Abstract Workflow Composition Tool (AWCT) is

responsible for workflow construction and uses responsible for workflow construction and uses backtracking from the final activity to the initial backtracking from the final activity to the initial activities of the workflow,activities of the workflow,

Executable Workflow Composition Tool (EWCT) - Executable Workflow Composition Tool (EWCT) - Extended process of workflow refinement that Extended process of workflow refinement that changes an abstract workflow into the executable changes an abstract workflow into the executable one,one,

Workflow Execution Engine (WfEE) is the place Workflow Execution Engine (WfEE) is the place where workflow is running in, it works on Petri-net where workflow is running in, it works on Petri-net principle of passing tokens,principle of passing tokens,


Data ComponentsData Components

Component Component databasedatabase

URLs of servicesDescriptions of jobs

Semantics of each component:-What type of data it produces-Its input-output transformation description-Its output-input transformation description

For each component:-Transformation of input tokens into input data-Transformation of output data into output tokens

Token Token databasedatabase

All existing tokens (both created by users and

produced by jobs/services

Token Token metadatametadata

Semantic description of all tokens in token database – based on required data parameters, it allows to identify the proper token


Workflow Construction ProcessWorkflow Construction Process

Component Component databasedatabase

Token Token databasedatabase

Token Token metadatametadata

We start with the semantic description of the required outputWe look for a token which would satisfy the requirementsNo such token is found; we look for a service or job which can produce token of such type

<token type=“mm5out”><x>120</x><y>250</y><start>2008-07-21</start></end>2008-07-22</end><width>300</width><height>150</height></token>

We have found a service which is able to produce the required token; however, it requires two input tokens, and

the search continues

Now we have found services which need only existing input tokens; so we have a workflow and input data, and the

application may start

We have produced the required output token (which represents the output data), the workflow has finished


Workflow Execution Workflow Execution ProcessProcess

Output placesActivityInput places

map

data

config

animation

timedata

1. We need input data

<map> <mapFile> map317.tif </mapFile></map>

<data> <dataFile> dispData.bin </dataFile></data>

<config> <density> 12 </density> <startTime> 1280982 </startTime></config>

2. Input tokens are combined into input data for the service or grid job

<inputStruct> <mapFile> map317.tif </mapFile> <dataFile> dispData.bin </dataFile> <density> 12 </density> <startTime> 1280982 </startTime></inputStruct>

3. This input data is used to call the service, or execute the grid job

4. The service/job returns output data

<outputStruct> <timeData> simul-out.txt </timeData> <animation> spread.avi </animation></outputStruct>

5. The output data is divided into tokens; these are annotated by metadata and stored into the database

<timedata> <timeData> simul-out.txt </timeData></timedata>

<anim> <animation> spread.avi </animation></anim>


Prototype implementation Prototype implementation of EWCT and WfEEof EWCT and WfEE

The functionality of this module was already tested The functionality of this module was already tested at the text-mining workflow that links together text at the text-mining workflow that links together text mining servicesmining services,,


Conclusions and Future WorkConclusions and Future Work

Software solution for automatic service workflow Software solution for automatic service workflow management, which considers not only services, but also management, which considers not only services, but also existing data in workflow construction,existing data in workflow construction,

Ontology describing semantics of the services from which Ontology describing semantics of the services from which the workflows are being composed, as well as of the the workflows are being composed, as well as of the available data and of the users which use the software, available data and of the users which use the software, and of course the domain vocabulary,and of course the domain vocabulary,

Users are able to exchange data and knowledge, and Users are able to exchange data and knowledge, and cooperate in the workflow construction and execution cooperate in the workflow construction and execution process.process.

Future research:Future research: full management of services using the WSRF family of standards,full management of services using the WSRF family of standards, richer monitoring during the execution phase in order to get more richer monitoring during the execution phase in order to get more

relevant QoS parameters relevant QoS parameters

Documents

Semantically-aided Data-aware Service Workflow Composition