Commitments to regulate social web services operation

Commitments to Regulate SocialWeb Services Operation

Zakaria Maamar, Noura Faci, Khouloud Boukadi, Quan Z. Sheng, Member, IEEE, and Lina Yao

Abstract—This paper discusses how social Web services are held responsible for the actions they take at run time. Compared to(regular) Web services, social Web services perform different actions, for instance establishing and maintaining networks ofcontacts and forming with some privileged contacts strong and long lasting collaborative groups. Assessing these actions’ outcomes,to avoid any violation, occurs through commitments that the social Web services are required to bind to. Two types of commitmentsare identified: social commitments that guarantee the proper use of the social networks in which the social Web services sign up,and business commitments that guarantee the proper development of composite Web services in response to users’ requests.Detecting commitment violation and action prohibition using monitoring results in imposing sanctions on the ‘‘guilty’’ social Webservices and taking corrective actions. A system for commitment management in terms of definition, binding, monitoring, andviolation detection is also discussed in this paper.

Index Terms—Social web service, social networking, commitment, monitoring, violation

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1 INTRODUCTION

WEB services are regularly hailed by IT academics andpractitioners for their capacity of developing busi-

ness processes that can cross organization boundaries atrun-time. According to the W3C, a Web service ‘‘is asoftware application identified by a URI, whose interfaces andbinding are capable of being defined, described, and discovered byXML artifacts and supports direct interactions with othersoftware applications using XML based messages via Internet-based applications’’. Web services exhibit usually threeproperties [4]: 1) independent as much as possible fromspecific platforms and computing paradigms, 2) primarilydeveloped for inter-organization cases, and 3) easy tointegrate into existing applications so that developingcomplex adapters for composition needs is not required.

Over the last few years, the R&D community has lookedinto Web services from a computation perspective withfocus on how Web services are described [40], published[16], discovered [47], composed together [19], made secure[20], made fault-tolerant [37], to cite just a few. Unfortu-nately other pending issues such as recommendation-based discovery and composition continue to underminethe benefits of adopting Web services as a technology ofchoice when developing cross-organization business-processes. To address some of these issues, we have been

looking into Web services from a new perspective thatdraws its essence from social computing (exemplified byWeb 2.0 applications like social networks and blogs). Ondifferent occasions we have demonstrated the synergybetween social computing and service-oriented computing(exemplified by Web services) [22], [23], [28], [30]. On theone hand, social computing is the computational facilita-tion of social studies and human social dynamics as well asthe design and use of information and communicationtechnologies that consider social context [43]. On the otherhand, service-oriented computing is the development ofapplications upon the principle of ‘‘I offer services thatsomebody else may need’’ and ‘‘I require services that somebodyelse may offer’’. Service offering and requirement illustrateperfectly what people experience (also how they behave) intheir daily life (e.g., at work, at home, and so on).

The synergy between social computing and service-oriented computing has resulted into social Web services.Compared to (regular) Web services, they establish andmaintain networks of contacts; count on their(‘‘privileged’’) contacts when needed; form with theircontacts strong and long lasting collaborative groups; andknow with whom to partner so that reconciliation effortsdue to ontology and policy disparities are minimized [28].These new actions are made possible because of the socialnetworks (e.g., collaboration, substitution, and competi-tion) that social Web services can now sign up in. Forinstance, a social Web service uses a collaboration socialnetwork to recommend the peers that it prefers to workwith in the case of composition and, also, uses a compe-tition social network to remain aware of the peers thatcompete against it in the case of selection.

When a social Web service signs up in a social network,it becomes exposed first, to the authority responsible formanaging this network and second, to the existingmembers (i.e., other peers) in this network. This socialWeb service also avails of the benefits of being a member ofthe network such as contacting other potential members

. Z. Maamar is with Zayed University, Dubai, U.A.E. E-mail: [email protected].

. N. Faci is with Universite Lyon 1, Lyon, France. E-mail: [email protected].

. K. Boukadi is with University of Sfax, Sfax, Tunisia. E-mail:[email protected].

. Q.Z. Sheng and L. Yao are with the University of Adelaide, Adelaide,Australia. E-mail: [email protected]; [email protected].

Manuscript received 5 Apr. 2012; revised 12 Mar. 2013; accepted 23 Apr.2013. Date of publication 12 May 2013; date of current version 13 June 2014.For information on obtaining reprints of this article, please send e-mail to:[email protected], and reference the Digital Object Identifier below.Digital Object Identifier no. 10.1109/TSC.2013.29

1939-1374 � 2013 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.

IEEE TRANSACTIONS ON SERVICES COMPUTING, VOL. 7, NO. 2, APRIL-JUNE 2014154

based on the profile they post on the network. Becausesocial Web services can now take different actions whoseoutcomes might ‘‘harm’’ peers in the same social network(e.g., revealing their private details), or even slowdown theoperation of this network (e.g., broadcasting irrelevantetails), we hold the social Web services accountable for theiractions so that monitoring who did what and when is deemednecessary. To this end, we adopt commitments as a means tofirst, guarantee the compliance of social Web services with thesocial networks’ regulations and second, detect any violationof these regulations so that corrective actions are takenpromptly. Regulations in a social network cover a wide rangeof aspects such as privacy, content sharing, registration, andpayment. The appropriateness of commitments for socialWeb services is elaborated in Section 2.3.

Our preliminary research results on commitments toregulate social Web services operation have been reportedin [26], where we discuss the general architecture support-ing this operation and present some commitment exam-ples. In this paper, we motivate further the adoption ofcommitments and build upon this architecture to

1. detail two main categories of commitments knownas social and business,

2. develop compositions that are driven by commit-ments,

3. structure commitments and detect their violations,4. and illustrate the deployment of this architecture

using a running scenario.

The rest of this paper is organized as follows. Section 2 is anoverview of social Web services and commitments in theliterature and a discussion of the motivations to adoptcommitments. Section 3 discusses the approach to regulatethe operation of social Web services using commitments.The different types of responsibilities that are mapped ontocommitments and the different types of sanctions in thecase of violation or prohibition are also presented. Section 4reports on the implementation of a system for commitmentmanagement. Finally concluding remarks and future workare reported in Section 5.

2 BACKGROUND

This section provides an overview of social Web servicesand commitments and concludes with a set of motivationsthat back the value-added of commitments to regulatesocial Web services operation.

2.1 Overview of Social Web ServicesSocial Web services are at the cross-road of two mainresearch streams: social computing and service-orientedcomputing. Existing research works either adopt Webservices to develop social networks of users or developsocial networks of Web services to address issues such asrecommendation-based discovery of Web services. Theblend of social computing with service-oriented computingis quite new. As a result, several research opportunities arestill un-taped.

In the category of social networks of users, we cite theresearch works of Maaradji et al. [31], Xie et al. [45],Al-Sharawneh and Williams [1], Wu et al. [44], Nam Ko et al.

[35], and Bansal et al. [3]. Maaradji et al. propose a socialcomposer (a.k.a SoCo) that advises users on the next actionsto take in response to specific events like selecting specificWeb services. Simply put, users check what their friends ina network did in the past so that they do the same ifappropriate. Xie et al. introduce a framework forsemantic service composition based on social networks.Al-Sharawneh and Williams mix semantic Web, socialnetworks, and recommender systems technologies to helpusers select Web services with respect to their functional andnon-functional requirements. Wu et al. rank Web servicesusing non-functional properties and invocation requests atrun-time. The popularity of a Web service as analyzed byusers is the social element that is used for ranking.Nam Ko et al. discuss the social Web in which a new type ofservices called ‘‘social-networks connect services’’ help thirdparties develop social applications without having to buildsocial networks. Last but not least, Bansal et al. examinetrust in the context of Web services discovery. On top ofWeb services’ functional and non-functional properties,users’ trust in the Web services’ providers can be used as anadditional selective criterion. Trust rating is assessed usingsocial network analysis, which is the process of mappingand measuring the relationships between a social network’snodes, for instance providers. This rating reflects thecentrality of a provider in a social network using threelevels known as degree, betweenness, and closeness.

In the category of social networks of Web services1, wecite the works of Maamar et al. [24], [27], [29], [30] and Chenand Paik [9]. In [24], Maamar et al. develop a method toengineer social Web services. Questions addressed in thismethod include what relationships exist between Webservices, what social networks correspond to these relation-ships, how to build social networks of Web services, andwhat social behaviors can Web services exhibit. In [27],Maamar et al. discuss the intertwine of social networks ofusers with social networks of Web services to compose,execute, and monitor composite Web services. Each net-work provides details that achieve this intertwine and thus,complete these operations. Three components are devel-oped: composer, executor, and monitor. The social com-poser develops composite Web services consideringrelations between users and relations between Webservices. The social executor assesses the impact of theserelations on these composite Web services during execu-tion. Finally, the social monitor replaces failing Web ser-vices to guarantee the continuity of these composite Webservices at run-time. In [29], Maamar et al. use social net-works of Web services to tackle the ‘‘thorny’’ problem ofWeb services discovery. Different social networks permit tocapture the situations (e.g., collaboration and recommen-dation) that Web services come across at run time. Webservices should not be treated as isolated components thatrespond to queries, only. Contrarily, they compete againstother similar Web services during selection, collaboratewith other different Web services during composition, andmay replace other similar Web services during failure

1. Readers are referred to [25] for more details on how to hold socialnetworks responsible for the actions affecting their members, namelysocial Web services.

MAAMAR ET AL.: COMMITMENTS TO REGULATE SOCIAL WEB SERVICES OPERATION 155

despite the competition.2 Maamar et al. in [30] discuss thedifferent social networks that social Web services can signup in, for instance supervision, competition, substitution,collaboration, and recommendation. The mining of thesenetworks results into identifying social qualities likeselfishness, fairness, and unpredictability that social Webservices exhibit at run time. Finally, Chen and Paik proposea methodology to build a global social service network inorder to improve service discovery [9]. After describingservices with light-weight ontologies the services arelinked together using social links. These links representfunctional relationships between the resource service andthe target services according to specific data correlations.

2.2 Overview of CommitmentsSingh et al. are the first of few who advocate for examiningService-Oriented Architecture (SOA) principles from acommitment perspective [42]. The traditional SOA is builtupon low-level abstractions that are inappropriate forcapturing the intrinsic and complex characteristics ofbusiness services such as autonomy, complexity, andadaptability. Contrarily a commitment-based SOA allowsto judge the correctness of a service enactment as long asthe commitments are not violated and to support businesscompliance without dictating specific operationalization.

Besides SOA, commitments are extensively adoptedin other disciplines that are concerned among otherthings with verifying agent interactions with the work ofEl-Menshawy et al. [11], specifying persuasion dialoguegames with the work of Bentahar et al. [7], analyzing ServiceLevel Agreements (SLAs) with the work of Paschke andBichler [39], and last but not least generating correctprotocols from contracts with the work of Narendra [36].El-Menshawy et al. indicate that existing approaches fail tocapture the meaning of interactions that arise in real-lifebusiness scenarios. Contrarily commitments capture the high-level meaning of messages, which make interaction protocolsflexible and intuitive. Bentahar et al. model a persuasion dia-logue game using commitments and arguments. Each game isspecified by its entry conditions, dynamics, and exit condition.Finally, Paschke and Bichler take repair actions in response toSLA violation by integrating event calculus and complexevent/action algebra into event condition action rules.

Commitments have also emerged as a key concept inmodeling e-business systems with the work of Xu et al. [46]and e-contracting applications for the semantic Web withthe work of Grosof and Poon [14]. Xu et al. discuss how toidentify the agents that will be blamed using intercon-nected commitments. Grosof and Poon define a contract asa set of business activities, a coordination mechanism thatmanages these activities between multiple agents, excep-tions that are violations of inter-agent commitments, andhandlers that manage these violations.

As stated earlier, commitments can be linked to SLAs[17] as well. Indeed SLAs are a form of commitments from aprovider to future consumers that a service will be made

available for use at a certain level (e.g., response time andsecurity level). Commitments adopted in this paper estab-lish, however, relationships from consumers to providersthat the regulations of these providers will be ‘‘obeyed’’. Incase of violation providers take actions against consumers.In SLAs consumers take actions against providers.

2.3 MotivationsThe increasing complexity of business processes calls formore than (regular) Web services that respond to users’queries, only. Indeed organizations adjust their processesregularly, develop new products and offer new services,engage in partnership relationships, etc. To deal with thiscomplexity, the research community has been examiningdifferent ways of enhancing Web services with additionalcapacities so that they become more responsive to theenvironment. A first option consists of making Webservices aware of the environment using context [10],[21], [32]. A second option consists of making Web servicesjoin communities for better exposure [6]. A third optionupon which this work is built consists of weaving socialelements into Web services operations like discussed inSection 2.1. To ensure the success of this weaving, socialWeb services need to be held accountable for the actionsthat they take with respect to the regulations of the socialnetworks in which they sign up. These regulations cover awide range of aspects such as privacy, content sharing,registration, and payment. Social Web services can takedifferent actions (e.g., establishing and maintaining con-tacts with peers) whose outcomes might ‘‘harm’’ peers inthe same social network (e.g., revealing their privatedetails), or even slowdown the operation of the network(e.g., broadcasting irrelevant details). Different questionsraise such as, are these actions taken on purpose, are thereguidelines to prevent similar actions from happening, andwhat are the consequences of these actions? To guaranteesocial Web services’ full compliance with social networks’regulations, we adopt commitments to specify and imple-ment the operation of social Web services. The followingreasons motivate this adoption:

. Commitments describe well how real life businessscenarios occur in terms of negotiation, delegation,cancellation, and discharge, which cannot be han-dled through simple SOAP-based binding (or invo-cation) operations.

. Commitments are associated with states that permitto follow up the interaction progress between theparties involved in these commitments known asdebtor and creditor. Each state is the result of ex-ecuting operations.

. Commitments can be used in conjunction with otherelements like trust and argumentation to developcomplex business-scenarios [12].

3 COMMITMENT-BASED APPROACH FOR SOCIALWEB SERVICES

This section discusses first, the architecture upon which ourcommitment-based approach is built. Afterwards it detailsthe commitments in terms of structure and monitoring.

2. Simultaneous cooperation (collaboration) and competition leadsinto coopetition [5]. Actors have, on the one hand, conflicts of interests(competition) and, on the other hand, common interests (cooperation).More on coopetition in the context of communities of Web services arereported in [18].


3.1 ArchitectureFig. 1 illustrates the architecture of our approach to specifyand implement social Web services operation using commit-ments. The architecture includes two worlds: computationaland operational. On the one hand, the computational worldhosts a pool of Web services and multiple social networks.These two reside in this world’s service and social levels,respectively. A Web service is referred to as social when itsigns up in a social network. On the other hand, theoperational world hosts a pool of user requests and differentcomposite social Web services. These two reside in this world’srequest and composition levels, respectively. Examples ofrequests include train booking and currency exchange. Thecompletion of complex requests like vacation planningrequires developing composite social Web services thatconsist of component social Web services.

Web services, social Web services, social networks, userrequests, and composite social Web services are theconstituents upon which our approach is built. Interactionsbetween some of these constituents lead into establishingand managing commitments. We identify two types ofcommitments: social and business. Social commitments areconfined into the borders of the computational world andarises when Web services sign up in specific socialnetworks. These commitments hold the social Web servicesresponsible for the actions that they take when using thesocial networks as a communication platform to reach outto other peers in these networks. This should guarantee thecompliance of the social Web services with the regulationsof the corresponding networks, otherwise corrective ac-tions like sanctions are taken. Contrarily business commit-ments connect the two worlds and arise when social Webservices take part in compositions. User requests areassigned to the social Web services for processing. Thesecommitments hold the social Web services responsible forthe actions that they take when taking part in ongoingcompositions. This should guarantee the participation ofthese social Web services in compositions and properbehaviors at run time. Contrarily to regular compositionscenarios [2], [15], [32], we rely on social networks to letsocial Web services recommend the peers that they wouldlike to collaborate with in the case of composition,recommend the peers that can substitute for them in thecase of failure, and be aware of the peers that competeagainst them in case of selection [28]. In general, a Webservice can sign up in the following three social networks:

. Collaboration social networks. By combining theirrespective functionalities, social Web services have the

capacity to work together on complex user requests.Consequently, a social Web service manages its ownnetwork of collaborators, so that it decides if it likescollaborating with peers based on previous experi-ences. A social Web service can also recommend peersto join under-development compositions.

. Substitution social networks. Although social Webservices compete against each other, they can stillhelp each other when they fail as long as they offersimilar functionalities. Consequently, a social Webservice manages its own networks of substitutes, sothat it can meet its SLAs when failure occurs. It canthen identify the best substitutes in response tousers’ non-functional requirements.

. Competition social networks. Social Web servicescompete against each other when they offer similarfunctionalities. Their non-functional properties dif-ferentiate them when users’ non-functional require-ments must be satisfied. Consequently, a social Webservice learns about its own network of competitors,so that it can attempt to improve its non-functionalproperties with respect to these competitors [2].

3.2 Social Commitments Towards Social NetworksSocial commitments are usually responsibilities contractedby one agent (called debtor) towards another (calledcreditor), raising the expectation that the debtor will actto satisfy these responsibilities [8]. We first, identify theresponsibilities that a social Web service binds to aftersigning up in a social network and then, discuss how thecommitments related to these responsibilities are modeled,managed, and enforced in order to avoid sanctions.

3.2.1 Responsibility DefinitionIn the following we assume that each network is led by anauthority component ðsnauthÞ that does many things such asconnect new Web services to existing members in thenetwork, assess the weights of edges connecting the Webservices, and enforce the regulations of the network.

To address the lack of relevant works on social networksof Web services, we looked at how users’ rights andresponsibilities are specified in some online social applica-tions like Facebook3 and LinkedIn4 so that we draw‘‘similar’’ rights and responsibilities for social Webservices. Moreover, in preparation for linking responsibil-ities to commitments (Section 3.2.2), we represent eachResponsibility ðRespÞ with three elements: 1) either obli-gation or permission5, 2) actions to perform, and 3) possibleconditions that authorize the execution of actions. Ourproposed responsibilities are listed below:

. Resp1. Collecting any detail ðdÞ in a social networkwould require indicating the purpose ðpÞ of thiscollection to this detail’s owner ðoÞ, represented asPermissionðCollectðd; o; validðpÞÞÞ. Collect is theaction, d is for instance a non-functional propertylike response time and is either public (made

Fig. 1. Commitments for social Web services operation.

3. www.facebook.com/legal/terms4. www.linkedin.com/static?key=privacy_policy&trk=hb_ft_priv5. Readers are referred to [34] for additional illustrations on

obligation, permission, and prohibition use.


available to all members of a social network),protected (made available to the social network’sauthority component, only), or private (not avail-able), o is the owner of d for instance social Webservice, p is the rationale of collecting d, and valid isa function that checks p. To identify the differentpurposes that requestors can use we studied thePlatform for Privacy Preferences Specification(P3P).6 This resulted in identifying two purposes:collaboration (col) to support the development ofcomposite Web services and substitution (sub) tosupport the execution continuity of Web service-based business processes in the case of failure.

. Resp2. Posting any detail ðdÞ on a social network shouldbe correct, represented as ObligationðPostðd; trueÞÞ.Post is the action and true is the veracity of d.

. Resp3. Collecting any detail ðdÞ from a social networkshould not be tampered afterwards, represented asObligationðnot-Tamperðd;o;collectionðdÞÞÞ. not-Tamperis the action and collection is a function that checks ifcollecting d is approved in compliance with Resp1.

. Resp4. Signing off from a social network would requirethe completion of all the pending assignments ðassÞ,represented as PermissionðSign-offðstatusðassÞÞÞ.Sign-off is the action and status is a function thatassesses the progress (e.g., ongoing, complete, andfailed) of ass.

. Resp5. Revealing any public detail ðdÞ to the non-members ðnotðmÞÞ of a social network should not beauthorized indefinitely, represented as Obligation

ðnot-Revealðd; o;m; collectionðdÞÞÞ. not-Reveal is theaction, m corresponds to the non-members of a socialnetwork, and collection is a function that checks ifcollecting d is approved in compliance with Resp1.

3.2.2 Commitment Structure and ManagementLargely studied in the multi-agent community [8], [41],Fornara and Colombetti note that ‘‘. . .intuitively a socialcommitment is made by an agent (the debtor) to another agent(the creditor), that some fact holds or some action will be carriedout (the content)’’ [13]. Conditions can also be linked tocommitments resulting in conditional commitments. Fig. 2

shows the life cycle of a commitment proposed in [41]using null, conditional, base, satisfied, and violated as statesand create, detach, discharge, cancel, and expire as operationsthat change commitments’ states. We first, propose astructure for our commitments and then, describe theirmanagement with respect to the interactions that occurbetween debtors (e.g., social Web service) and creditors (e.g.,social network’s authority component). violated state isdetailed in Section 3.2.3.

Structure. We adopt the formalism of Fornara andColombetti to structure our commitments with respect tothe aforementioned list of responsibilities ðResp1...5Þ. Thisformalism is as follows [13]: CRespiðdebtor; creditor;content½jcondition�Þ where CRespi is a commitment associat-ed with Respi and [ ] means optional. For the sake ofsimplicity, we map a responsibility onto one commitment,only.

. CResp1ðswsi; swsj; Collectðd; swsjÞjvalidðpdÞÞ is a con-

ditional commitment by swsi to swsj, that if validðpdÞholds then Collectðd; swsjÞ will be satisfied.

. CResp2ðswsi; snauth; PostðdselfÞÞ is a commitment by

swsi to snauth, that PostðdselfÞ will be satisfied. selfrefers to swsi.

. CResp3ðswsi; swsj; not-Tamperðdpublic; swsjÞ

jcollectionðdpublicÞÞ is a conditional commitment byswsi to swsj, that if collectionðdpublicÞ holds thennot-Tamperðdpublic; swsjÞ will be satisfied.

. CResp4ðswsi; snauth; Sign-offðÞjstatusðassÞÞ is a condi-

tional commitment by swsi to snauth, that ifstatusðassÞ holds then Sign-offðÞ will be satisfied.

. CResp5ðswsi; snauth; not-Revealðdpublic; o; nmÞ

jcollectionðdpublicÞÞ is a conditional commitment byswsi to swsj, that if collectionðdpublicÞ holds thennot-Revealðdpublic; o; nmÞ will be satisfied.

Management. We adopt the life cycle of Fig. 2 toillustrate commitment changes in response to, first, theinteractions that occur between debtors and creditors and,second, the monitoring that creditors perform over thecommitments to assess either their satisfaction or theirviolation at run-time.

Using Fig. 2, we consider a Web service ðwsiÞ as a debtorand a social network through either its authority compo-nent ðsnauthÞ or one of its members ðswsjÞ as a creditor. Wedefine the interactions between debtors and creditors withperformatives like those defined in the speech act theory[38]: performativeðfrom: sender; to :receiver; content :actionjstatementÞ. Performative is a speech act that the senderuses to express either 1) a directive (e.g., request and advice)that makes the receiver take a particular action, 2) commis-sive (e.g., promise) that makes the sender commit to someaction in the future, or 3) assertive that makes the sendercommit to the truth of a statement.

Initially wsi and snauth exchange request ðfrom : wsi; to :snauth; content : sign upðreasonsÞÞ and inform ðfrom : snauth;to : wsi; content : approvaljrefusalÞ where reasons includesupporting arguments (e.g., high reputation/trust level) forwsi to join the network. In the case of approval (criteria likeimproving the welfare of all members of a social network orarguments given bywsi can be used to either approve or reject6. www.w3.org/TR/P3P11/#ppurpose

Fig. 2. Commitment’s life cycle ([41]).


a sign-up decision, but this is outside this paper’s scope),snauth registerswsi in its social network. As a first result wsi isnow referred to as social Web service ðswsiÞ and has to complywith all the responsibilities of this network. The compliancebegins when snauth executes create operation so that all thecommitments take on conditional state (for non-conditionalcommitments likeCResp2

, base state is automatically taken afterconditional state). Since Resp1 and Resp4 have a permissivenature, this requires additional performative exchangesbetween first, swsi and swsjði6¼jÞ due to the interest that swsihas in swsj’s details (requestðfrom : swsi; to : swsj; content :collectðd; purposeðpÞÞÞ a n d permit ðfrom : swsj; to : swsi;content : approvaljrefusalÞ) and second, swsi and snauth dueto the desire that swsi has in leaving the social network(requestðfrom : swsi; to : snauth; content : sign offðreasonsÞÞand permit ðfrom:swsj; to :swsi; content : approvalj refusalÞ)where reasons include supporting arguments for wsi toleave the network. Arguments can be disagreement withthe authority component regarding the sanctions andrewards.

In addition to the conditional state that some commit-ments take, other states are taken as well for the followingcases:

1. If a commitment’s condition holds, e.g., validðpdÞ,then detach operation is executed making thiscommitment take on base state. Different ways existto assess the conditions of commitments dependingon the nature of responsibilities.

. Resp1: swsj checks that p is either composition orsubstitution.

. Resp3: swsj checks that d is public and swsi hasthe permission to collect d.

. Resp4: snauth checks that status of ass iscomplete.

. Resp5: swsj checks that d is public and swsi hasthe permission to reveal d.

2. If a commitment’s content is satisfied, e.g.,Collectðd; swsjÞ, then discharge operation is execut-ed making this commitment take on satisfied state.Otherwise, a cancel operation is executed makingthis commitment take on violated state.

3. If swsi signs off from a social network, then expireoperation is executed making all the commitmentstake on null state except for CResp4

since Resp4 holdsindefinitely.

3.2.3 Violation and Prohibition HandlingFig. 2 includes violated state to indicate that social Webservices might not honor the commitments that they bindto for reasons such as being malicious or temporaryshortage of computation resources. Detecting violations ispossible using monitoring [33], which can be coupled tocompensation in order to take corrective actions. Besidescommitment violation, it may happen that social Webservices carry out actions that are prohibited. This raisesthe importance of setting sanctions like decrementing theirreputation levels and/or revoking some access privileges.

We list in the following how the five previous commit-ments ðCResp1...5

Þ are subject to either violation, prohibition,or both. We associate violation and prohibition withcommitment content and condition, respectivelyðCRespiðdebtor; creditor; content½jcondition�ÞÞ. We also asso-ciate compensations and sanctions with creditors anddebtors, respectively.

. CResp1: violation arises when collection occurs over a

non-public detail, and prohibition arises when thepurpose of a detail collection is neither compositionnor substitution.

. CResp2: violation arises when incorrect details are

posted on a social network.. CResp3

: violation arises when a collected detail istampered, and prohibition arises when a detail iscollected without approval.

. CResp4: violation arises when signing off from a social

network happens without approval, and prohibitionarises when an assignment is left incomplete.

. CResp5: violation arises when a detail is revealed to a

social network’s non-member, and prohibitionarises when a detail is collected without approval.

Whether violation or prohibition, monitoring the actionsof social Web services is required. We assign the monitor-ing to the social network’s authority component ðsnauthÞ aswell as to the members ðswsjÞ of this network. For eachcommitment we suggest ways of monitoring and thecompensation and sanction operations in response to theviolations or prohibitions:

CResp1:

. Violation monitoring requires that swsj reports tosnauth recurrent, tentative accesses to its non-public details from swsi. If these tentatives areconfirmed using logs for example, this will be aviolation to accessing non-public details on swsj.Sanctions consist of reviewing the trust/reputationlevels of swsi if first time. Otherwise, eject swsifrom the social network if these levels go below athreshold.

. Prohibition monitoring requires that snauth checksif swsj was really used either as a component inan under-development composition or as a sub-stitute in an under-execution composition for thepurpose that swsi mentioned to snauth so that itcollects details on swsj. If swsj was not used asexpected, this would be a prohibition to collectingdetails on swsj. Compensations include informingswsj of what happened as well as giving it moreaccess privileges like tracking all the peers thatrequest its details.

CResp2:

. Violation monitoring requires that snauth checks theveracity of the self-details that swsi posts. To this endit tracks swsi’s operations over time. If this veracityis not confirmed, this will be a violation to postingvalid details. Compensations include forcing swsi toreview its details.


CResp3:

. Violation monitoring requires that snauth checks howswsi uses the details it has collected from swsj. If theintegrity of these details is not maintained, thiswill be a violation to collecting details on swsj.Compensations include either posting/refreshingnew/existing details on swsj.

. Prohibition monitoring requires that swsj reports tosnauth any detail that was collected by swsi withoutits approval. If this is confirmed using logs forexample, this will be a prohibition to collectingdetails on swsj. Sanctions include revisiting thetrust/reputation levels of swsi if first time. Other-wise, eject swsi from the social network if theselevels go below a threshold.

CResp4:

. Violation monitoring requires that snauth checks allthe sign-off activities of swsj in a social network. If asign off happens without approval, this will be aviolation to leaving the social network. Compensa-tions include enforcing the sign-off regulations andinforming other peers of these regulations.

. Prohibition monitoring requires that snauth makessure that all the assignments of swsi are completeaccording to a specific time frame. If this is not thecase, this will be a prohibition to completing theseassignments. Sanctions include revisiting the per-formance level of swsi first time. Otherwise, ejectswsi from the social network if this level goes belowa threshold.

CResp5:

. Violation monitoring requires that snauth checks allthe details that swsi posts on its social network onswsj that it is not part of this network making surethat swsi has the necessary approvals from swsj. Incase these approvals are missing, this will be aviolation to revealing details on swsj. Compensa-tions include informing swsj of what happened aswell as giving it more access privileges like trackingall the peers that request its details.

. Prohibition monitoring requires that swsj reports tosnauth any detail that was collected by swsi withoutits approval. If this is confirmed using logs forexample, this will be a prohibition to collectingdetails on swsj. Sanctions include revisiting thetrust/reputation levels of swsi if first time. Other-wise, eject swsi from the social network if theselevels go below a threshold.

3.3 Business Commitments Towards CompositionsSimilar to how we analyzed social commitments in thecomputational world in terms of responsibility definition,commitment structure and management, and violation andprohibition handling, we proceed with the same forbusiness commitments connecting the computationalworld to the operational world. These commitments havesocial Web services as debtors and compositions as

creditors. We define the future responsibilities of socialWeb services when they engage in compositions inaccordance with their already-defined responsibilities inthe social networks.

3.3.1 Responsibility DefinitionWe assume that each composition is driven by anorchestration component ðcomporchÞ that does among otherthings look for the necessary social Web services to appendinto the composition, fix the semantic mismatches betweenthe social Web services in the composition, trigger theexecution of the social Web services in the composition,and process the recommendations of social Web services interms of expanding the composition with new peers orsubstituting the failing social Web services with otherpeers. We define a responsibility with three elements:obligation7, actions to perform, and possible conditions thatauthorize the execution of actions. Our proposed respon-sibilities are listed as the following:

. Resp6. Exchanging any detail ðdÞ in a compositionshould require indicating the expected use ðuÞ ofthis detail by the recipient ðcÞ. A detail correspondsto any data reported in a business process that acomposition implements. As per our previouswork on Web services’ control and operationalbehaviors [40], we identify two potential uses for adetail, namely control and operational behaviorbuilding. This responsibility is represented asObligationðSubmitðd; c; validðuÞÞÞ. Submit is theaction, d is for instance a data like price and ismade available to the orchestration componentand other members of a composition, c is therecipient for instance a peer, u is the rationale ofexchanging d, and valid is a function that checks u.

. Resp7. Sharing any detail ðdÞwith all components ofa composition including the orchestration compo-nent should be correct. This responsibility referssomehow to Resp2 where a social Web service isexpected to post valid details on a social network,represented as ObligationðShareðd; trueÞÞ. Share isthe action and true is the veracity of d.

. Resp8. Recommending a social Web service ðswsÞ tothe orchestration component should require stating itsprofile ðfÞ in terms of functional and non-functionalproperties and role ðrÞ in a composition either as acollaborator or as a substitute. This responsibilityrefers somehow to Resp1 since collecting detailson a social Web service for possible participationin a composition requires its permission, representedas ObligationðRecommendðcomporch; sws; f; validðrÞÞÞ.Recommend is the action, sws is the recommended peerthat comporch will either append into the compositionor replace a failing component in the composition, f isthe profile of sws, r is the role of sws, and valid is afunction that checks r.

. Resp9. Fulfilling the pending assignments ðassÞ ofa failing peer should be taken care by thesubstitute social Web service ðswsÞ. Resp9 is a

7. No permissions are allowed because of the user-driven nature ofcompositions.


post-effect to Resp8 fulfillment, represented asObligationðFulfillðsws; assÞÞ. Fulfill is the ac-tion, sws is the substitute social Web service thatwill join an ongoing composition, and ass is thelist of pending assignments of the failing peer.

. Resp10. Guaranteeing the ‘‘proper’’ functioningðfuncÞ of a potential collaborator social Web serviceðswsÞ should be done by the recommending peerso that other peers’ operation continuity andsafety are maintained. It is represented asObligationðGuaranteeðsws; funcÞÞ. Guarantee isthe action, sws is the new social Web servicethat will be appended into an ongoing composi-tion, and func represents its operation.

3.3.2 Commitment Structure and ManagementWe propose a structure for our business commitments andthen, describe their management with respect to theinteractions that occur between debtors (e.g., social Webservice) and creditors (e.g., composition’s orchestrationcomponent).

Structure. We adopt the same formalism used earliernamely CRespiðdebtor; creditor; content½jcondition�Þ.

. CResp6ðswsi; swsj; Submitðd; swsjÞjvalidðudÞÞ is a con-

ditional commitment by swsi to swsj, that if validðudÞholds then Submitðd; swsjÞ will be satisfied.

. CResp7ðswsi; comporch � swsj; ShareðdselfÞÞ is a com-

mitment by swsi to comporch that Shareðdself Þ will besatisfied. self refers to swsi.

. CResp8ðswsi; comporch;Recommend ðcomporch; swsj; fÞj

validðrswsjÞÞ is a conditional commitment by swsi tocomporch, that if validðrswsjÞ holds then Recommendðcomporch; swsj; fÞ will be satisfied.

. CResp9ðswsj; swsi; Fulfillðswsj; assswsiÞÞ is a commit-

ment by swsj to swsi that Fulfillðswsj; assswsiÞ willbe satisfied.

. CResp10ðswsi; swsj; Guaranteeðswsj; funcÞ

jvalidðfuncswsjÞÞ is a commitment by swsi to swsj thatGuaranteeðswsj; funcÞ will be satisfied.

Management. We consider this time a social Webservice ðswsiÞ as a debtor and a composition’s orchestrationcomponent ðcomporchÞ as a creditor. The interactionsbetween debtors and creditors are defined with performa-tives and are driven by the needs to either collaborate orsubstitute. For illustration we only discuss the collabora-tion interactions and assume that swsi is already part of acomposition.

Initially swsi and comporch exchange request ðfrom :swsi; to : comporch; content : recommendðswsjÞÞ and inform

ðfrom : comporch; to : swsi; content : approvaljrefusalÞ. swsisuggests adding swsj to the composition led by comporch.Upon approval, comporch makes swsj a member of thecomposition and informs other existing members if neces-sary. As a first, direct result swsj has to comply with all theresponsibilities of this composition in terms of exchangingdetails and recommending collaborators and substitutes.The compliance begins when comporch executes createoperation so that all the commitments related to swsj takeon conditional state (for non-conditional commitments like

CResp7, base state is automatically taken after conditional

state). Further to the conditional state that some commit-ments take, other states are taken as well as per thefollowing cases:

1. If a commitment’s condition holds, e.g., validðudÞ,then detach operation is executed making thiscommitment takes on base state. Different waysexist to assess the conditions of commitmentsdepending on the nature of responsibilities.

. Resp6: swsj checks that u is either for control-behavior building or for operational-behaviorbuilding.

. Resp8: comporch checks that r is either collabora-tor or substitute.

2. If a commitment’s content is satisfied, e.g.,Guaranteeðswsj; funcÞ, then discharge operation isexecuted making this commitment takes onsatisfied state. Otherwise, cancel operation isexecuted making this commitment takes onviolated state.

3. If swsi fails in a composition, then expire operation isexecuted making all the commitments related toswsi take on null state.

3.3.3 Violation and Prohibition HandlingWe list in the following how the five additional commit-ments ðCResp6...10

Þ can be subject to either violation, prohi-bition, or both. Similar to what we did for the socialcommitments, we associate first, violation and prohibitionwith commitment content and condition, respectively andsecond, compensations and sanctions with creditors anddebtors, respectively.

. CResp6: violation arises when detail submission

occurs without the request of the recipient. Andprohibition occurs when a detail is used though thesender of the details did not approve its use.

. CResp7: violation arises when incorrect details are

exchanged in a composition.. CResp8

: violation arises when the profile of arecommended social Web service is not correct.And prohibition arises when a social Web serviceis appended into a composition though its role isnot valid.

. CResp9: violation arises when a substitute social Web

service does not fulfill the pending assignments ofthe failing peer.

. CResp10: violation arises when a collaborator social

Web service is appended into a composition thoughits proper functioning is not guaranteed.

Whether violation or prohibition, monitoring the actionsthat social Web services take as components in composi-tions is required. We assign the monitoring to orchestrationcomponents ðcomporchÞ and social Web services ðswsiÞ aswell. For each commitment we suggest ways of monitoringand compensation and sanction operations in response tothe violations or prohibitions.


CResp6:

. Violation monitoring requires that swsj reports tocomporch the inappropriateness of the details that itreceives from this comporch. If this happens regularly,this will be a violation to flooding swsj withinappropriate details. Sanctions include decreasingthe trust level of the social Web services that sentthese details to comporch.

. Prohibition monitoring requires that swsi checks ifthe details that it sends to comporch are used asexpected (i.e., for control- and operational-behaviorbuilding). If this is not the case, this will be aprohibition of inappropriately using swsi’s details.Compensations include informing swsi of whathappens as well as giving it more privileges suchas questioning the rationale of sending its details.

CResp7:

. Violation monitoring requires that comporch checksthe veracity of the self-details that swsi shares withother components in the composition. To this end ittracks swsi’s operations over time. If this veracity isnot confirmed, this will be a violation to sharinginvalid details with other components. Sanctionsinclude decreasing swsi’s trust level so that otherpeers can properly assess the veracity of the detailsthey receive.

CResp8:

. Violation monitoring requires that comporch checksthe correctness of swsj’s profile. If this correctness isnot confirmed, this will be a violation to recom-mending social Web services. Sanctions include

decreasing the trust level of the recommendingsocial Web services ðswsiÞ.

. Prohibition monitoring requires that comporch checksif the swsj’s role is played as expected (i.e.,collaboration or substitution). If this is not the case,this will be a prohibition to append swsj into thecomposition of comporch. Compensations includeinforming swsi that swsj was not appropriate forthis composition.

CResp9:

. Violation monitoring requires that comporch checks ifswsj fulfills the pending assignments of swsi in thecomposition. To this end it tracks swsj’s operationsover time. If this fulfilment is not confirmed, this willbe a violation to honoring its assignments. Sanctionsinclude decreasing swsj’s reputation level.

CResp10:

. Violation monitoring requires that comporch checks ifswsj properly operates in the composition. To thisend it tracks swsj’s operations over time. If thisproper functioning is not confirmed, this will be aviolation to letting swsj collaborate with othercomponents in this composition. Sanctions includedecreasing swsj’s reputation level so that other peersdo not consider it as a potential collaborator in theirrespective social networks.

4 IMPLEMENTATION

4.1 System DesignFig. 3 illustrates the architecture that supports install socialWeb services (in terms of connection to the social networksand interaction with each other) and managing commit-ments (in terms of creation, update, satisfaction, anddeletion). The architecture is a stack of three levels, namelyservice, social, and monitoring. The first two levels corre-spond to the levels reported in the computational world inFig. 1. At the service level, a Web service ðwsÞ requestsentry to the social network authority ðsnauthÞ of a socialnetwork (at the social level). Upon approval, the snauthinstalls a social Web service ðswsÞ that will act on behalfof this ws in the network and updates two repositoriesdenoted by commitments ðCRespiÞ and SWSs details. Theformer stores commitments so that their statuses areknown as per the life cycle of Fig. 2. The latter storesWeb services’ functional and non-functional propertiesand the interactions’ outcomes between the swss andthe snauth as well (e.g., rejecting a sign-off request).These two repositories are shared between the snauthand the MonitorManager. The MonitorManager andObserverManager together form the monitoring level inFig. 3.

Fig. 4 is the class diagram of the architecture of Fig. 3.Several classes are identified including CMonitorManager,CObserver, CObserverManager, C LifeCycle, and C Resp.CObserverManager deploys instances of CObserver so that

Fig. 3. System architecture.


they report to CMonitorManager the events that occur inthe social network such as message exchange between asws and the snauth, and operations in the social network(e.g., collecting private details). CMonitorManager pro-cesses these events together with respect to the instancesof C LifeCycle to determine when a concrete commit-ment (associated with C Resp class) is created, satisfied orviolated, or expired. In Fig. 5, CResp (with Condition andContent) describes a CRespk ’s structure (Section 3.2.2). Letus consider CResp2

ðswsi; snauth; PostðdselfÞÞ as an examplewhere swsi and dself are variable names (i.e., any socialWeb service and any self-detail, respectively). These lattercorrespond to possible values for the debtor (resp.varParamA) attribute of CResp (resp. Content). Uponacceptance of a new Web service ðsws1Þ in the socialnetwork, the snauth creates an instance of each CRespk¼ð1;3;5Þwhere swsi is replaced with sws1 and stores the commit-ments in the commitment repository. CRespk is also asso-ciated with expCdt that represents the condition underwhich the snauth removes a CRespk instance from the re-pository of commitments. A commitment data-structure isgeneric; the list of pre-defined commitments can be enrichedwith no changes in the CMonitorManager functionalities.

Eclipse IDE for Java and PostgreSQL 8.4 were used toimplement the system. First, we developed differentGraphical User Interfaces (GUIs) to cater for the needs ofproviders of SNs and providers of WSs. We also decom-posed the prototype’s functionalities as follows. The pro-viders of SNs launch the deployment of three instances:CSN Auth, CMonitorManager, and CObserverManager. Allthese instances are implemented as concurrent threads. AWS provider submits to a SN details on its Web serviceðwsÞ like name, business domain, and execution time aswell as its WSDL and the reputation level (Section 3.2.2).Then, CSN Auth compares this latter with some thresholdsto decide whether it approves the request or not.

To carry out experiments, we generated in two differentways a list of observations ðobsListÞ that corresponds toswss taking social actions as per their CRespk (e.g.,PostðresponseTimeÞ). The first way is to select these actionsthrough a GUI (Fig. 6). Here, CObservers are implementedas Java-Event Listeners. The second way is to automatically

generate the social actions through the correspondingCObserver; for instance ‘‘HotelWS would like to collectlistOfPlace from PlaceBookingWS for the purpose ofcollaboration’’.

4.2 ExperimentsWhen a social Web service becomes a member of a socialnetwork, an administration module is created to manage itslife cycle based on the social commitments that it will bindto at run time (Fig. 6). For instance, social actions such ascollecting and posting data are invoked through thisadministration module. As aforementioned, this modulesimulates CObserver to generate events and report them toCMonitorManager as well. This latter also has an adminis-tration module to select the violation/prohibition detectionstrategy from two alternative options (FIFO-based andpriority-based), as well as violation/prohibition handling.These options schedule the handling of violations andprohibitions. The first option considers FIFO screening ofthe social commitment events with respect to their occur-rence order, while the second considers priority screeningof the social commitments. Priorities are established ac-cording to the social actions and can vary upon user’srequest. In the current implementation, priorities estab-lishment occurs as follows:

Fig. 4. Architecture’s class diagram.

Fig. 5. Commitment data-structure.


. A detail in a sws’s profile has a sensitivity level toindicate if permission is required before collection.For instance, a private detail may have a negativeimpact on the reputation level if leaked.

. Social actions are sorted based on sanctions appliedon Web services in case of commitment violation/prohibition. For instance, ‘‘Reveal private detail’’ðC Resp5Þ has a higher priority than ‘‘Collect publicdetail’’ ðC Resp1Þ. Violating C Resp3 (‘‘Tamper de-tails‘‘) corresponds to more serious sanctions thanC Resp4 (‘‘Sign Off with pending assignments’’) andC Resp2 (‘‘Post invalid details’’).

In the following, we illustrate some cases of violationand prohibition. We first consider that hotelWS is about tocollect data on PlacebookingWS where ‘‘Collect data’’ is asocial action related to Resp1 (i.e., ‘‘Collecting any detail (d)in a social network would require indicating the purpose (p) ofthis collection to this detail’s owner (o)’’). Let’s assume that d islistOfPlace and p is ‘‘collaboration’’. As listOfPlace isprivate, unauthorized peers should not collect it even if p isvalid. CMonitorManager updates the list of commitment

status with this violation (Fig. 7). In Fig. 7, CMonitorManageralso reports another violation related to CResp5

(‘‘Revealingany public detail (d) to the non-members (not(m)) of a socialnetwork should not be authorized’’). In this case, WeatherWStries to reveal a GPS localization to BBCWeather that is a non-member of the network. This violation is ranked first in thepriority list of CMonitorManager, since CResp5

has a highpriority than C Resp1.

Still in Fig. 7 that shows C Resp1’s violation because ofthe private nature of listOfPlace and a prohibition be-cause HotelWS is neither a component in the under-develop-ment composition that includes PlaceBookingWS nor asubstitute for PlaceBookingWS. These violation and prohibi-tion are reported from CMonitorManager to the SN Auth.

As per Fig. 6, HotelWS is not engaged in any compo-sition. In the second part of experiments, we engageHotelWS in a composition referred to as TravelPlanner.The following describes briefly TravelPlanner in terms ofcomponent Web services along with some responsibilitiesconverted into business commitments. On top of HotelWSfor hotel booking, it needs other components includingFlightWS for airline reservation, CarRental or TaxiWS for

Fig. 6. Event generation interface.

Fig. 7. Status of social commitments using priority prohibition/violation option.


ground transportation, CurrencyWS for currency ex-change, WeatherWS for weather forecast, and BillWS forbilling. HotelWS collects accommodation deals for theperiods requested by customers. It can also suggest re-deeming loyalty points in return of free-of-chargestransport. WeatherWS returns weather forecast for thesaid periods so that either indoor activities like museumvisits or outdoor activities like cruises are planned. BillWSproposes different payment options to customers. In caseof credit card payment, BillWS contacts PaymentWS toauthorize payment. For experimental needs, we assumethat AccommodationWS is a substitute for HotelWS.

A customer through PaymentWS agrees to pay if the tripis planned and booked properly. After receiving the pay-ment agreement from the customer, PaymentWS notifiesFlightWS and HotelWS of the payment authorization.Following HotelWS’s unexpected failure due to servercrash, AccommodationWS is a good candidate to substituteHotelWS so that the same quality of service is maintained.Before recommending any peer using HotelWS’s substitu-tion social network and as per C Resp8, HotelWS has theobligation to state this peer’s profile and role to the or-chestration component in charge of executing TravelPlanner

(Fig. 8a). HotelWS collects details on AccommodationWS

with its permission as per C Resp1 (a social commitment).The purpose of this collection is substitution. C Resp1 issatisfied if AccommodationWS accepts to substitute HotelWS

in TravelPlanner. In the same way, C Resp8 is satisfiedif the role stated to the orchestration componentcorresponds effectively to the purpose of this collection.Upon acceptance, AccommodationWS has the obligation toresume all the pending assignments of HotelWS ðResp9Þ.AccommodationWS is thus committed to fulfilling this ob-ligation ðC Resp9Þ. However, AccommodationWS delays itsparticipation due to other higher priority requests (Fig. 8b).Thus, violating C Resp9 affects negatively its reputationcausing the cancellation of hotel booking due to delay inconfirming the booking. A potential side-effect is thatFlightWS will be constrained to cancel the flight and requestrefunds with financial penalties.

5 CONCLUSION

In this paper, we have presented an approach to regulatesocial Web services operation using commitments. Twotypes of commitments have been identified: social andbusiness. The former focus on the membership regulationsof Web services in social networks so that these Webservices can be referred to as social Web services. Thelatter focus on the participation of social Web services incompositions. Commitments have been deemed appro-priate because of the actions that social Web services carryout compared to (regular) Web services such as establish-ing and maintaining networks of contacts, counting ontheir contacts when needed, and forming with other peersstrong and long lasting collaborative groups. Each com-mitment is structured using three elements: debtor,creditor, and content that could be subject to conditions.Monitoring violation and prohibition on commitments hasalso been examined in this paper. The objective is to de-velop compensations and sanctions in response to theseviolations and prohibitions, respectively. A system im-plementing the techniques proposed in this paper isreported. In particular, we discuss the commitment man-agement in terms of definition, binding, monitoring, andviolation detection.

There are several research directions in our future work.Firstly, we plan to develop techniques for checking theconsistency of commitments so that deadlocks or conflictsare avoided. Secondly, we will identify additional com-mitment violation and action prohibition types. Thirdly,we plan to draw rights and responsibilities from realnetworks of social Web services. We also plan to developstrategies enabling the ‘‘guilty’’ social Web services toargue about their actions prior to sanctioning them.

ACKNOWLEDGMENT

The authors would like to thank the anonymous reviewersfor their valuable comments and suggestions that helpedimprove the quality of this paper.

Fig. 8. Status of business commitments using FIFO prohibition/violation option.


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Zakaria Maamar received the MSc and PhD degrees in computersciences from Laval University, Quebec, Canada, in 1995 and 1998,respectively. He is a Professor in the College of Information Technologyat Zayed University in Dubai, United Arab Emirates. His researchinterests are primarily related to service-oriented computing, socialcomputing, and system interoperability.

Noura Faci received the PhD degree in computer sciences from ReimsUniversity, Reims, France, in 2007. She has been an AssociateProfessor at the University Lyon 1, Lyon, France, since October 2008.Her research interests are fault tolerance in multi-agent systems,dependable e-business systems, and service computing. Prior, shewas a Research Associate at King’s College London, London, U.K. inthe Agents and Intelligent Systems Group where she led a workpackage as part of a CONTRACT European IT Research Project.

Khouloud Boukadi received the PhD degree in computer science fromEcole des Mines, Saint Etienne, France. She is an Assistant Professorin the Computer Science Department at the Faculty of Economics andManagement of Sfax, Tunisia. She is a member of the Multimedia,Information systems & Advanced Computing Laboratory (Miracl, www.miracl.rnu.tn). Her research interests include service computing, Webservices in the cloud, context-aware computing, and agility ofInformation systems.

Quan Z. Sheng received the PhD degree in computer science from theUniversity of New South Wales, Sydney, Australia. He is an AssociateProfessor in the School of Computer Science at the University ofAdelaide, Adelaide, Australia. His research interests include service-oriented architectures, Web of Things, distributed computing, andpervasive computing. He was the recipient of the 2012 Chris WallaceAward for Outstanding Research Contribution and the 2003 MicrosoftResearch Fellowship. He is the author of more than 130 publications.Dr. Sheng is a Member of the IEEE and the ACM.

Lina Yao is currently a PhD student in the School of Computer Scienceat the University of Adelaide. She received the Master and Bachelordegrees, all in computer science, from the University of Adelaide,Adelaide, Australia, and Shandong University, Shandong, China,respectively. Her research interests include Web mining, knowledgemanagement, Internet of Things, and service-oriented computing.

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Commitments to regulate social web services operation

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