2012 13th ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing
A Survey on Service Contract Yucong Duan DISCo, University of Milano-Bicocca, Milano, Italy Email:
[email protected]
Abstract—Service contracts function as interfaces which bridge IT implementation, business modeling, and economical analysis for service systems among various stakeholder from a holistic perspective. This paper conducts a review of recent research and practice on service contracts with focus on service contract content and service contract management. Dimensions of { Quality of data(QoD), Quality of service(QoS), Legal issue, Context, Business term } are introduced to evaluate service contract content. Dimensions of { Description of contract, Monitor/Control, Selection, Matchmaking, Composition } are introduced to evaluate service contract management Based on the survey, we propose possible directions for future efforts. Keywords-service contract; content; lifecycle; management; quality; business
I. I NTRODUCTION This paper extends on the work of [13].A service contract embodies the information covering the profiting demand of customers, the expectation of users and the implementation capability of IT technology on target services which will be deployed in a business process and validated by economical analysis. A fair service contract should realize the tradeoff of interest for all stakeholder. Although every stakeholder might want to maximize the interest on his/her own side by negotiating on the content of the contract, there are some knowledge which if absent from their minds, will not complete a contract which will realize his/her goal or even attain a clear tradeoff among his/her own multiple interests. Since service contract is a pretty new thing which is essentially interdisciplinary[4], there are many encouraging progress from different domains in different directions and on different aspects in both industrial and research communities[5]. A good standardization on aspects such as common inter-organizational vocabulary[4], templates of service content, negotiation mechanism[4], communication protocol, validation techniques and public judical infrastructure, etc, will contribute as a comprehensive reference for contract content making and management plan with high guarantee of feasibility. However there is not enough shared standard which can be relied for the time being. We want to contribute to accelerate the process of sharing the best knowledge and practice related service contract and promote the improvement.In particular, the intended contributions of this paper are: • Knowledge accumulation: we want to contribute to the accumulation of relevant knowledge and experience on 978-0-7695-4761-9/12 $26.00 © 2012 IEEE DOI 10.1109/SNPD.2012.22
Figure 1.
•
Interest related service contract
service contract content and service contract management by summarizing recent best practice and research. Indication:we want to contribute by indicating possible directions for research and practice on service contract based on analyzing of the literature based on the integrated perspectives of economical analysis, business modeling and IT implementation[17].
We clarify the targeted scope of our work and the adopted integrated perspective as follows: (1) Target scope We identify the target scope of our work on service contract based on the analysis of (i) shared interest of individual stakeholder within a specific service contract, and (ii) interest of public society represent the interest of society as a whole. We identified that (i) and (ii) are relatively independent since that (ii) is related to all service contracts and (i) is for individual contract. However if not guided, (i) will be a result of negotiation which will not follow the general interest of the whole society. We also identify that the progress of (ii) will not necessarily against (i). So we choose to consider both (a) the shared interest among stakeholder for a service contract, and (b) try to contribute to the perfect of public interest, during our exploring for service contract research and study. An illustration of the interplay of interests can be found in Figure 1. (2) Value centric integrated perspective 805
to service contracts from both industrial community and research community. Category terms are defined as: • Contribution: a summary of some characteristics of the work related to practice and research on service contract; • Limitation: some aspects which can be supplied or enhanced from the comprehensive view which considers the interplay among business model, IT implementation, economical goal for service contract. III. S ERVICE CONTRACT CONTENT
Figure 2. contract
We identified that a complete coverage of contract content is shared interest of all stakeholder since that it details every necessary information which if it is absent might leave an unguided gap which could ruin a service project. To catering the goal of quality evaluation of contract for qualification checking and performance evaluation, we adopt the both perspectives of quality of the data in service contract at data level and the quality of service at service level. For the purpose of enforcement for both clarifying commitments and law reference, we adopt the legal issue perspective. For specifying the specific condition of each concrete service contract, we adopt the context perspective. The perspective of business term is introduced to observe the direct description of business and economical issues. Empirically we adopt the following dimensions: • QoD: multiple metrics which are used to describe data quality,e.g., completeness, reliability (information), accuracy, consistency, timeliness, cleaning, and interpretability[30]; • QoS: performance, e.g., start/end time, response time, latency, and service throughput and dependability e.g.,availability, accessibility, reliability (function), and security [30]; • Legal issue: usage permission, e.g., licenses which describe { adaptation, composition, derivation} for function and {distribution, transfer, personal use, commercial product} for data[30], and misuse related regulations/actions, e.g., { copyright, liability, law enforcement[34], intellectual property rights}[30]; • Context: conditions which are associated with data resources and services[32]; • Business term:terms used in pricing models, e.g., flat rate,pay-per-use[30], and business activities, e.g., credit, commence, insurance, audit, cost/price analysis, marketing. Table II shows initial evaluation on related works. (”V” stands for positive, ”X” stands for negative.) From Table II and with regard to the content of the literature, we also identify the following information: (1) Although there are 8 works which touch QoD, most of them only implicitly cover some factors and a few of them did systemic research or sufficient practice at present.
The proposed value centric integrated perspective on service
We adopt a value centric perspective for guiding the feasibility of our work. The key ideas include: (i) economical analysis validates the success or fail of a business, and economical progress drives business improvement;(ii) economical goals has the highest priority in determining the adoption of contract content and management activities of service contract lifecycle; (iii) service contract need to provide support for implementation of economical analysis; (iv) service contract realizes business process through representing business interfaces during service interactions implemented with IT technology; (v) service contract restricts the content of IT implementation, and IT implementation need to confirm to service contract as commitments; (vi) public standards and law facility enact the smooth running of service contract based system at social level in real world. This integrated perspective is adopted by us to verify the feasibility of related work and predict the progressing directions. An illustration of the described scenario is shown in 2. The rest of the paper is organized as follows: Section II presents the state of the art of service contract research and practice in both academic and industry societies. Section III evaluates service contract content of related work. Section IV evaluates service contract management of related work. Section V proposes possible future directions based on our previous analysis. Section VI concludes the paper. II. S TATE OF THE ART To fulfill the investigation of current state of service contract research and practice, we explored extensively on available related literature of the past three years on the web (we expect to improve the completeness of coverage in the next extension). Since service contract is essentially an intercapillary concept, we do not limit the target scope to web service but also other domains such as industrial manufacturing and software outsourcing, etc. Table I shows the literature which are dedicated to, utilize or are related
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Rel. [19] [35] [6] [21] [37]
Contribution service traffic shaping in Service-Oriented Networking(SON) guide for making content for proactive execution of contracts Model contract management process in a contract lifecycle use contracts to relieve risks in service provision Construct a description logic model of contracts for accountability management
[18]
Compare fixed cost contracts with performance based contracts for short term contracts deliver services according to runtime requests for next generation of service network(NGN) propose a QoS based contracting framework and abstract simulation based analysis Behavioral contract based formal model for service discovery and composition Formal model on identifying equivalence relationship of services Design of general purpose service contract content A formal model of the execution of services bundled by contracts among agents A comprehensive solution for both design time and runtime aspects of SOA design based on contracts A runtime model of autonomic service cooperation SLA design for service contracts Summarize contracting for availability (CfA) for long term relationship Model variability of execution of service contracts in a business process Explicitly model and specify data contracts to support concern aware data selection and utilization with QoD Formalize the notion of contracts between interacting services to enable service evolution without propagation propose a four phases methodology based on ontology vocabulary for service negotiation Compare the specification style of temporal logics, operational and deontic specifications for modeling Provide a specification language - USDL to model business and operations for contracting and monitoring Present an automated manner to explain non-compliance between WSAgreement documents Provide solutions for composability and conformance identification and checking at design time It extracts property descriptions from heterogeneous, dynamic and distributed information on the Web and a distributed computation architecture
[27] [11] [7] [24] [8] [29] [36] [16] [3] [12] [1] [33] [2] [4] [15] [28] [22] [23] [26] and [25] [10]
Deal with the heterogeneity of service contracts in service composition
Limitation limited to the context of SON Liabilities of parties can be added Many details need to be provided to concretize the proposed framework designed for industrial OEM manufacturing scenarios tasks of formal modeling can be simplified by assigning into several stages in real cases Limited for short term contracts limited to NGN background adopt several hypotheses such as the existence of a broker, and incomplete information sharing, etc Real case study is absent for validation of proposed abstract model Real case study is absent for validation Intended for domain independent context A formal model designed for agent based systems Use agents and relies on centralized infrastructure Designed for agent based systems
negotiation mechanism can be introduced for run time content and management adaptation Only change effect on clients is considered, and extended influence on entire value-chain is not largely at conceptual level and from academic perspective focus mainly on modeling behavior protocol aspect More service properties need to be considered further standardization of templates will make it more appealing Protocols and templates can be used to avoid communication errors, and economical goals can be referred for validation of incompatibility Characters such as contract interaction behavior checking, e.g. for deadlock, and checking on composed contracts can be added Dynamic changes during the composition as a result of negotiation can be considered
Table I C ONTRIBUTION AND LIMITATION .
description of service contracts is the foundation of contract management; identification of qualified service contracts is the basic requirement for service filtering; finding the most proper service contract is a concretization for guaranteeing the best success of a business which is a shared interest by all stakeholder; and composition of services not only constructs functionally qualified service system but also creates more possibilities for quality optimization and competitive business choices. Composition of functions of services will help to broad the scope of candidate solutions and enable that there are more chances to find the best solution which might have better performance, more added value and less cost than individual services which provide the same function.During service composition, information or data of individual services could be integrated to provide more value/usages as a whole than individually. Properly monitoring and controlling of execution of service contracts are inseparable part for a service project. An illustration of the interplay between main stakeholder and main management activities during service contract lifecylce can be found in Figure3
(2) QoS is well studied and practiced especially in the form of SLA although without the presence of a standardization of terminology. (3) 13 works touch legal issues however most of them are implicitly related since that corresponding law infrastructure and judical system which are dedicated to SOA and cloud computing tendency are still undergoing construction process. (4) 8 works touch context however most of them are implicit. (5) Business terms are extensively covered although most of them are in an incomplete manner. Very few of them touches the potential of evacuating the potential of added value originating in service composition. The added value and the group behavior could be clarified, such as in well organized subcontracting relationships. IV. S ERVICE CONTRACT LIFECYCLE To evaluate the work on service contract management, we try to consider the shared interest of all stakeholder in contract lifecycle[6]. We adopt the views that proper
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Related work Jarma .et [19] Wrighta and Fergussonb [35] Bochicchio and Longo [6] Meiera .et[21] Zou .et[37] Homburg and Stebel [18] Simoni .et [27] Comuzzi and Pernici [11] Bravetti and Zavattaro [7] Padovani [24] Burbon [8] Telang and Singh [29] Zimmermann [36] Gao .et [16] Berberova and Bontchev [3] Datta and Roy [12] Abu-Matar and Gomaa [1] Truong .et [33] Andrikopoulos .et [2] Bicer .et [4] Fenech .et[15] Spillner .et [28] Muller .et[22] Nepal and Zic [23] Panziera .et [26] and Palmonari .et [25] Comerio .et [10]
QoD
QoS V V V X V V V V X V V X V X V V V V V X V V V V V
Legal issue X X V X X X V X V X V X X V X X X V V V X V V V V
Cont -ext X V V X X X X V X X V X X V X X X V X X X X X X V
Busine -ss term X V V V V V X V X X V V X X V V V V X X V V V V V
X X X V X X X V X X V X X X V X X V X X X X X V V V
V
V
V
V
Table II S ERVICE CONTRACT CONTENT.
Related work Jarma .et [19] Wrighta and Fergussonb [35] Bochicchio and Longo .et [6] Meiera .et [21] Zou .et [37] Homburg and Stebel [18] Simoni .et [27] Comuzzi and Pernici [11] Bravetti and Zavattaro [7] Padovani [24] Burbon [8] Telang and Singh [29] Zimmermann [36] Gao .et [16] Berberova and Bontchev [3] Datta and Roy [12] Abu-Matar and Gomaa [1] Truong .et [33] Andrikopoulos .et [2] Bicer .et [4] Fenech .et [15] Spillner .et [28] Muller .et [22] Nepal and Zic [23] Panziera .et [26] and Palmonari .et[25] Comerio .et [10]
Descr -ption V V V X V V X X V V V X V X V X V V V X V V V V V
Moni /Cont V X V V V V V X X X X V X V X X X V[31] X X X V X X V
Selec -tion X X V X X X V V X V X X X X X X V V[31] X X X X X X V
Match -make X X V X X X X V X V X X V X X X X V V X X X V X V
Comp -sit X X X X X X X X V V X X V X X X V V V V V V X V X
V
X
X
V
V
Figure 3. Main management activities of stakeholder during service contract lifecycle
to adopted proactive/reactive actions on content, behavior and organization during runtime; • Selection: negotiation and ranking activity, technique and strategy of locating services which best meet the comprehensive preferences of stakeholder among multiple candidates[11], [9]; • Matchmaking: activity, technique and strategy of filtering providers/services by retaining those that satisfy requestors’ requirements and budget constraints[11]; • Composition: activity, technique and strategy of organizing functions and integration of data/information of services to meet existing requirement or create added value. From Table III and with regard to the content of the literature, we also identify the following information: (1) Although there are 9 works which cover some factors of Matchmaking, only a few of them did systemic research or sufficient practice until now. (2) There are 19 works on description of service contracts. An unification of the related knowledge and experience will contribute by enabling the reuse of the best practice and experience since it is a very broad topic. (3) Monitor and control has been studied or covered in 11 works. Aside from normal network, NGN and Cloud demand specific care which has been realized but not still have a lot to be studied and practiced. (4) Selection of service contract has been covered by 7 works. However very few of them has proceeded to
Table III S ERVICE CONTRACT MANAGEMENT.
Empirically we adopt the following dimensions: • Description of contract: activity and implementation process of describing service contract content; • Monitor/Control: monitor refers to tracing/checking the quality of behavior, traffic or output, and control refers
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on service contract content and improvement on service contract management are in accordance with each other along the direction of attaining both business and economical success. Environment specific: there are many special environments such as agent based mechanism, SaaS and NGN[27] which present new implementation environment which need to be considered during service contract making and management to cater the new requirement and better profit from them. Business modeling: although some related research and practice have spared some efforts on business modeling[1], relying relationship from IT decision making to business implementation should be further emphasized during creation of individual service contracts and among service contracts from both short term business perspective and long term business strategy. Value based: it will be a never satisfied goal for using value based[14] analysis and validation to optimize the contract content and contract management towards attaining better economical goals which can be shared by both stakeholder and society. Intelligent adaptation mechanisms such as autonomous proxy agents and self healing techniques from existing successful practices can be introduced to guarantee a runtime and reliable adaptation towards catering the economical goals. Validation and computation efficiency: service contract content validation, behavior checking, performance monitoring and runtime adaptation are computation intensive tasks which could benefiting from well scheduled computation workload scheduling to attain better efficiency, such as employing distributed matchmaking and ranking [25] instead of centralized computation, sharing runtime feasibility validation and behavior checking workload by introducing completeness validated template/standards for content making and deadlock free behavior protocol, etc. Public administration and Law infrastructure: as other successful business practices, success of service contract practices relies on the inseparable support from both public administration and relative judical system which are not really completed regretfully at present. It is highly demanded that IT specialists, law specialists and government staff can work together to conquer this challenge.
explicitly relate the criteria of selection with the economical success which is the ultimate goal of both business initiative and IT implementation. Lack of an integrated consideration of these links will weaken the feasibility of applying research output in real practice. (5) Composition of service contract has been covered by 11 works. However many possible and important extensions on it have not been studied and practiced. An example is that the added value on the integrated information and composed functionality of several integrated services which surpasses the coverage of composing individual service contracts is not fully considered. V. ROADMAP :
FUTURE DIRECTIONS
Based on previous analysis, we present our suggestions for future directions for research and practice under an integrated consideration of relationships: (1) Maximization of economical profiting is the goal of business transaction; (2) Selection of IT technology should integrate consideration of business goals; (3) Enabling the feasibility of a project is a shared dimension of interest of all stakeholder at global social level; (4) Enhancing the economical performance of a business through optimization on the structure of service composition architecture and the behavior of service composition implementation is not necessary in conflict with the interest of individual stakeholder and could provide a venue for benefiting some or all stakeholder in the form of creating added value; (5) Negotiating process on service contract is a mutual process for stakeholder to both understanding capability of each other better and understand intentions of themselves better; (6) Service contract layouts the foundation for enabling business mode based on services, economical analysis on business and IT tasks organization. In general, we identify that there is huge space for further enhancement from the integrated perspective where economical success is with the highest priority. We propose the following future directions: Enriching and standardizing: it is highly demanded to detail and standardize the information on QoD, Legal issues, Context for service contract content, and deepen the research and practice on Selection, Matchmaking, Composition of service contract management. Domain specific: domain specific service contracts will be of high demand for better fitting specific situations of a domain in real world practice where service contracts should fit the domain features[20] which are shared as reusable professional knowledge within a specific domain. Enhancing feasibility from integrated views: enhancing feasibility of service contract demands consideration of integrated view which will guide that the modification
VI. C ONCLUSION We identify that if it is not guided, the result of the tradeoff of service contracts among several competitive or cooperative stakeholder could not represent the best choice from the economical view at the whole society level. A properly made service contract will provide support for reaching the best of economical goal for both stakeholder and the whole society. We have evaluated the state of art of service contracts with a focus on both content of service contract and management of service contract in a service lifecycle from empirically selected perspectives. We have
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identified some directions for future research and practice based on the analysis. Our survey and analysis is featured with the integrated view of considering the core concerns: (1) Making the project possible is basic shared interest by all stakeholder;(2) Providing guide for service contract management; (3) Providing support for optimization for economical progress. The integrated consideration enables the unification of maximization of the capability of service contract for the society, and the maximization of the acceptance and satisfaction of all stakeholder.
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