QoS-aware middleware for web services composition: a qualitative approach

Web services exhibit major industrial benefit by their ability to participate in composition processes. Web services composition allows for automated exchange of information among remote processes through the service interface. A well-established end-to-end QoS infrastructure among the involved processes precludes confusion among the developers, vendors and consumers. Most of the research work conducted in this domain has focused on functional QoS requirements such as service response time, delay, cost, etc. This paper elaborates the QoS of web services from the perspective of data freshness and accuracy. Towards this aim, the ‘Region Switching’ (RS) algorithm is introduced in this paper. Within the context of the multiple web services composition scenario, the RS-algorithm allows for accurate identification of the point of information change and the appropriate re-computation over the subset of the pre-established, global service execution plan. Thereafter, a mathematical model is presented to verify the need for re-computation based on certain estimated factors, computed thresholds, and the model design. Such a selective re-computation is worth considering since some services may take a significant amount of time to produce results where a slight change to the information set might not alter the outcome of the service. The proposed concept is implemented by utilising and extending the WS-Notification specification in order to elaborate a middleware that is capable of sensing and routing information change at the level of web services using the publish-subscribe mechanism. The contribution of this paper is threefold. First, it highlights the importance of qualifiable QoS aspect related to the issue of web services composition and monitoring. Second, it describes an algorithm capable of capturing and reflecting the state of web services involved in a composition process, thereby achieving higher QoS. Finally, the paper illustrates the use and extension of the WS-Notification concept in building such systems that would deliver up-to-date information to the user through selective re-computation of the web services composition plan.     

A method towards Web service combination for cross-organisational business process using QoS and cluster

How to quickly combine various Web services to support cross-organisational business processes is the key technical problem in service computing. Because of the changeability of QoS of Web services, the traditional methods are unadaptable to the new environments. In this paper, a new service composition method, called Improved Self-organising neural network Method for Web Service Composition, is proposed to achieve QoS-aware Web service combination, according to using the clustering technology. First, fuzzy mathematics is used to express each QoS attribute and the improved self-organising neural network is used to cluster services to reduce the number of candidate services. Secondly, all the centre of each cluster is selected and formed a composite service by using an exhaustive algorithm. Thirdly, the service cluster that is represented by the concrete services. Finally, the optimal service combination can be selected using integer programming or genetic algorithm. The experimental result shows the efficiency of Web service composition and demonstrates the applicability.     

QaaS (quality as a service) model for web services using big data technologies

Quality of service (QoS) determines the service usability and utility and both of which influence the service selection process. The QoS varies from one service provider to other. Each web service has its own methodology for evaluating QoS. The lack of transparent QoS evaluation model makes the service selection challenging. Moreover, most QoS evaluation processes do not consider their historical data which not only helps in getting more accurate QoS but also helps for future prediction, recommendation and knowledge discovery. QoS driven service selection demands a model where QoS can be provided as a service to end users. This paper proposes a layered QaaS (quality as a service) model in the same line as PaaS and software as a service, where users can provide QoS attributes as inputs and the model returns services satisfying the user’s QoS expectation. This paper covers all the key aspects in this context, like selection of data sources, its transformation, evaluation, classification and storage of QoS. The paper uses server log as the source for evaluating QoS values, common methodology for its evaluation and big data technologies for its transformation and analysis. This paper also establishes the fact that Spark outperforms the Pig with respect to evaluation of QoS from logs.     

A service governance mechanism based on process mining for cloud-based applications

ABSTRACT

With the widely use of cloud computing in enterprise information systems, service governance becomes critical for an enterprise to adapt to a changing business environment. In order to provide a dynamic strategy for continuous service governance, in this paper a comprehensive service analysis solution is proposed to address both design time and run-time requirements for cloud applications. First, a process-centric Semantic Scene Model is composed to combines static business requirements with dynamic execution information. Then service analysis is conducted referring both to the business process mining results from event logs and the Semantic Scene Model given by business model designers. Service governance strategies are generated from the service analysis results and are performed to qualitatively classify the Quality of Service (QoS) of the services. Finally the approach is verified with a transportation logistics service application in a cloud platform. The result shows that our method can get continuous service governance through combining business processes with run-time service analysis.     

OSGi及其QoS获益驱动动态软件体系结构研究

随着软件领域中移动计算、分布计算和Web Service等技术的迅速发展,软件计算环境变得越来越开放、复杂、多元。如何应对不断变化的计算环境,构建一个自适应的动态软件架构,受到了越来越多的关注。文章首先介绍一个成功的软件系统结构框架实例——Open Service Gateway Initiative(OSGi)。然后,以请求质量QoS为核心,对面向服务的OSGi框架进行扩展,提出了一个动态自适应软件架构解决方案,它以用户QoS属性为目标驱动,通过动态调整软件自身结构,以进一步提高用户期望的服务质量。实验结果证明了该调度框架的有效性。     

The M/G/∞ Queueing Model for Optimistic Concurrency Control

The M / G /∞ queue with Optimistic Concurrency Control (OCC) is a model for a special form of parallel transaction processing in a real-time database. Transactions arrive according to a Poisson process and require some generally distributed execution time. One of the differences with ordinary multi- and infinite-server queueing models is that under OCC the successful completion of one transaction may immediately cause the failure of one or more of the other transactions. This happens if the completing transaction has overwritten a data-item that is in use by another transaction in progress. As soon as this failure is detected the failed transaction is restarted. So the total service time of a transaction consists of its final successful run and the time spent on unsuccessful runs.
In this study we develop an approximation for the distribution of the total service time, and test the approximation against simulation. Although in practice the number of servers is never unlimited, this study provides valuable insight in the asymptotics with respect to the number of servers. The approximation clearly demonstrates the very limited performance gain from an increase of the number of servers.     

FROM TRANSACTION COST TO TRANSACTIONAL VALUE ANALYSIS: IMPLICATIONS FOR THE STUDY OF INTERORGANIZATIONAL STRATEGIES*

This article examines interorganizational strategies from a transactional value, rather than transaction cost, perspective. It argues that the transaction cost perspective has at least two major limitations when used to analyse interorganizational strategies: (1) a single-party, cost minimization emphasis that neglects the interdependence between exchange partners in the pursuit of joint value, and (2) an over-emphasis on the structural features of interorganizational exchange that neglects important process issues. We propose instead a transactional value framework for analysing interorganizational strategies that addresses (1) joint value maximization, and (2) the processes by which exchange partners create and claim value. We discusses the implications of the present approach for the study of interorganizational strategies and for the transaction cost perspective itself.     

Facilitating offshoring with enterprise technologies: Reducing operational friction in the governance and production of services

The development of cheap and robust communications technologies has lowered the cost of conducting business transactions across international boarders and opened up low wage rate global labor markets to firms facing demand for cheap and efficient service delivery. A review of transaction cost theory and operations management models of service process disaggregation reveals parallels between the how firm boundaries are determined and how certain service process elements can be disaggregated from face-to-face customer contact. This theoretical background is used to identify challenges to the effective offshoring of service processes. The competitive capability literature offers suggestions as to how firms might acquire the internal capabilities required to manage offshore service processes. Propositions are developed on how the standardized transactional infrastructure of enterprise technologies (and the organizational competencies developed by successful enterprise system adopters) may help mitigate the challenges of offshore governance.     

Achieving runtime adaptability through automated model evolution and variant selection

Dynamically adaptive systems propose adaptation by means of variants that are specified in the system model at design time and allow for a fixed set of different runtime configurations. However, in a dynamic environment, unanticipated changes may result in the inability of the system to meet its quality requirements. To allow the system to react to these changes, this article proposes a solution for automatically evolving the system model by integrating new variants and periodically validating the existing ones based on updated quality parameters. To illustrate this approach, the article presents a BPEL-based framework using a service composition model to represent the functional requirements of the system. The framework estimates quality of service (QoS) values based on information provided by a monitoring mechanism, ensuring that changes in QoS are reflected in the system model. The article shows how the evolved model can be used at runtime to increase the system's autonomic capabilities and delivered QoS.     

A service-based framework for pharmacogenomics data integration

Data are central to scientific research and practices. The advance of experiment methods and information retrieval technologies leads to explosive growth of scientific data and databases. However, due to the heterogeneous problems in data formats, structures and semantics, it is hard to integrate the diversified data that grow explosively and analyse them comprehensively. As more and more public databases are accessible through standard protocols like programmable interfaces and Web portals, Web-based data integration becomes a major trend to manage and synthesise data that are stored in distributed locations. Mashup, a Web 2.0 technique, presents a new way to compose content and software from multiple resources. The paper proposes a layered framework for integrating pharmacogenomics data in a service-oriented approach using the mashup technology. The framework separates the integration concerns from three perspectives including data, process and Web-based user interface. Each layer encapsulates the heterogeneous issues of one aspect. To facilitate the mapping and convergence of data, the ontology mechanism is introduced to provide consistent conceptual models across different databases and experiment platforms. To support user-interactive and iterative service orchestration, a context model is defined to capture information of users, tasks and services, which can be used for service selection and recommendation during a dynamic service composition process. A prototype system is implemented and cases studies are presented to illustrate the promising capabilities of the proposed approach.     

Innovation ecosystems as a service: Exploring the dynamics between corporates & start-ups in the context of a corporate coworking space

The desire to create innovative organizational spaces has led to various instantiations of innovation ecosystems. Towards this direction, there is a growing interest in establishing corporate innovation ecosystems in the form of ‘corporate coworking spaces’ (CWS). From a relational ontological standpoint, this study builds on the collaborative spaces literature with the aim to investigate the emerging dynamics between corporates and start-ups in an innovation ecosystem. Through an abductive research strategy (ARS) as well as service design methods, we explore how co-creation between corporates and start-ups emerges (or not) in an innovation ecosystem that serves as a collaborative space in Denmark. Our empirical findings challenge the mostly overenthusiastic connotations and thus the study contributes to the critical coworking research stream. More specifically, we give emphasis on the co-constructive entanglement of socio-spatial arrangements and we propose a framework for revisiting the design of CWS through 1) balancing the engineered and evolving parts of the ecosystem, 2) facilitating stakeholder alignment, 3) adopting a service-oriented approach and 4) developing inclusive strategies. Apart from the implications for scholars and practitioners who study and design CWS, we argue that future research would especially benefit from building on a service-oriented approach of innovation ecosystems and we call for more interdisciplinary research.     

基于QoS优化的面向服务流程分解方法

面向服务的业务流程分解是构建面向服务系统的前提。文章分析了复杂业务过程的QoS因素及其计算,提出一种基于QoS的服务流程分解方法。该方法首先应用OWL-S(Ontology Web Language for Services)进行流程建模,再对OWL-S模块进行归并、组合,将复杂业务流程转化成由几种典型结构构成的服务组合形式,通过服务组合和流程QoS约束的计算,实现流程分解的优化。最后通过一个汽车贷款审批的实例验证了分解方法的有效性。     

管理制度中的交易成本:理论与实践

管理制度在执行过程中往往会产生各种各样的交易成本,从某种意义上说,管理执行中的交易成本的高低决定着管理制度能否顺利实施乃至执行效果的好坏。降低管理执行中的交易成本应成为设计管理制度时的重中之重。实践表明,制度"物化"、管理信息系统、利益"木马"、效率工资与文化能有效降低管理执行中的交易成本。     

Analysis of interactions among core,transaction and relationship-specific investments: The case of offshoring

Through the use of core, transactional and relational specificity constructs, the paper studies how the emphasis of clients’ who move business processes offshore, changes over time to represent complex relationships between investments in core, transaction and relationship-specific assets. The complex combination of these investments helps clients attain evolving objectives in offshoring alliances. Interpretive Structural Modelling (ISM) has been used to establish changing emphases of the specific elements in offshoring alliances.     

A new three-dimensional manufacturing service composition method under various structures using improved Flower Pollination Algorithm

With the growing complexity of customer requirements and the increasing scale of manufacturing services, how to select and combine the single services to meet the complex demand of the customer has become a growing concern. This paper presents a new manufacturing service composition method to solve the multi-objective optimization problem based on quality of service (QoS). The proposed model not only presents different methods for calculating the transportation time and transportation cost under various structures but also solves the three-dimensional composition optimization problem, including service aggregation, service selection, and service scheduling simultaneously. Further, an improved Flower Pollination Algorithm (IFPA) is proposed to solve the three-dimensional composition optimization problem using a matrix-based representation scheme. The mutation operator and crossover operator of the Differential Evolution (DE) algorithm are also used to extend the basic Flower Pollination Algorithm (FPA) to improve its performance. Compared to Genetic Algorithm, DE, and basic FPA, the experimental results confirm that the proposed method demonstrates superior performance than other meta heuristic algorithms and can obtain better manufacturing service composition solutions.     

Research on manufacturing grid resource service optimal-selection and composition framework

In order to address the resource service optimal-selection (RSOS) and composition problem in manufacturing grid (MGrid) system and provide high-quality service to users, an MGrid RSOS and composition framework (MGrid-RSOSCF) is investigated in this study. The process of RSOS and composition is divided into the following five steps in MGrid-RSOSCF: (1) decomposing the submitted manufacturing task into several subtasks (i.e. single resource service requested task) if the submitted task is a multiple resource service requested task; (2) searching out the qualified resource service for each decomposed subtask and generating the corresponding candidate resource service set; (3) retrieving, evaluating and comparing the quality of service (QoS) for each candidate resource service, and provide data for service optimal-selection and composition –if the submitted task is a single resource service requested task; (4) evaluating synthetically the overall quality of each candidate resource service and ranking them, and selecting the optimal one for the task – if the submitted manufacturing task is an multiple resource service requested task; (5) selecting one candidate resource service from each candidate resource service set and constructing a new composite resource service according to the submitted task requirements, and collecting all the possible resource service composite execution paths (RSCEP) and selecting the optimal paths to execute the task. The proposed MGrid-RSOSCF consists of five layers and each layer provides the corresponding necessary services and algorithms to address one problem mentioned above. The five layers are: (1) T-layer, responsible for MGrid task decomposition; (2) S-layer, responsible for resource service match and search; (3) Q-layer, responsible for QoS processing; (4) O-layer, responsible for evaluating and ranking the candidate resource service and (5) C-layer is responsible for resource service composition and optimal-selection. The case study and comparison of performances of the algorithms demonstrate that the proposed methods are sound on success rate and executing efficiency.     

Reusing process fragments for fast service composition: a clustering-based approach

With the proliferation of Web services over the Internet and due to the increasing complexity of users’ needs, Web service composition has emerged as a powerful method of software reuse, allowing to deliver complete business processes as a set of interacting services. To guarantee a rapid and secure service composition, fragments of available business processes at different granularities may be considered as a composition unit and recombined to deliver effective compositions. Despite the benefits of this method, most of the existing works do not take into consideration the reuse of service process fragments (SPF). Reusing SPFs allows, not only to minimize the composition time, but also to improve the reliability of the composition process. In this paper, we propose a Web service composition approach that aims to combine service process fragments rather that atomic services. We adopt a powerful mathematical model called Formal Concept Analysis (FCA) to define the relationships between services and fragments. Moreover, we exploit the regrouping capabilities of FCA by proposing algorithms for the extraction of candidate fragments’ combinations. A scoring function is also defined to determine the quality level of each SPF and its ability to participate in a composition. The experimental studies proved the effectiveness of our FCA-based approach compared to existing state-of-the-art solutions.     

The number of securities giving the maximum return in the presence of transaction costs

An essential element of any realistic investment portfolio selection is the consideration of transaction costs. Our purpose, in this paper, is to determine the maximum return and the corresponding number of securities to buy giving such return, whenever practical constraints features related to budget, buy-in thresholds, and transaction costs are taken into consideration. Dealing with the portfolio selection and optimization problem in the point of view of individual investors, we will arrive to get an analytic result, leading to a new and simple alternative solution to heuristic algorithms. Moreover, this result can be considered as another approach to integer optimization.     

Explaining Vertical Integration Strategies: Market Power, Transactional Attributes and Capabilities

abstract    We analyse vertical boundaries of firms by identifying and comparing industrial, transactional and firm-specific factors in such a way that industrial organization, new institutional economics and the capability-based view are all taken into account. After testing the model in 155 firms in the Spanish meat industry, we observe that only factors associated with both transaction costs and capabilities have a statistical and economic relevance for explaining vertical integration. Firms vertically integrate to create specific investment between stages of the value chain, to internally exploit their pool of knowledge and capacities, and to guarantee quality of inputs and services employed. On the other hand, firms avoid high levels of vertical integration in the presence of high demand changes in order to stay flexible. Finally, providers or clients with market power do not seem to affect vertical boundaries in any consistent way.