Quality Of Service Composition Research Articles

Trusted QoS Assurance Approach for Composite Service

The characteristics of service computing environment, such as service loose coupling, resource heterogeneity, and protocol independence, propose higher demand for the trustworthiness of service computing systems. Trust provisioning for composite services has become a hot research spot worldwide. In this paper, quality of service (QoS) planning techniques are introduced into service composition-oriented QoS provisioning architecture. By QoS planning, the overall QoS requirement of the composite service is decomposed into separate QoS requirement for every constituent atom service, the QoS level of which can subsequently be satisfied through well-designed service entity selection policies. For any single service entity, its QoS level is variable when the deployment environment or the load of service node changes. To mitigate the uncertainty, we put forward QoS preprocessing algorithms to estimate the future QoS levels of service entities with their history execution data. Then, based on the modeling of composite service and QoS planning, we design three algorithms, which include the time preference algorithm, cost/availability (C/A) preference algorithm, and Euclidean distance preference algorithm, to select suitable atomic services meeting the user’s requirements. Finally, by combining genetic algorithm and local-search algorithm, we propose memetic algorithm to meet the QoS requirements of composite service. The effectiveness of the proposed methods by which the QoS requirements can be satisfied up to 90% is verified through experiments.

A Dynamic QoS Adjustment Enabled and Load-balancing-aware Service Composition Method for Multiple Requests

Previous QoS-aware service composition methods mainly focus on how to generate composite service with the optimal QoS efficiently for a single request. However, in the real application scenarios, there are multiple service requests and multiple service providers. It is more important to compose services with suboptimal QoS and maintain the load balance between services. To solve this problem, in this paper, we propose a service composition method, named as dynamically change and balancing composition method (DCBC). It assumes that the QoS of service is not static, and the services can adjust the value of QoS to gain more opportunities to be selected for composition. The method mainly includes two steps, which are the preprocessing step and the service selection step. In the preprocessing step, a backward global best QoS calculation is performed which regarding the static and dynamic QoS respectively; then guided by the global QoS, the feasible services can be selected efficiently in the service selection step. The experiments show that the DCBC method can not only improve the overall quality of composite services but also guarantee the fulfill ratio of requests and the load balance of services.

Performance evaluation of a solution for composite service selection problem with multiple consumers

In recent years, building business applications from independently developed services has become one of the current trends in service computing. To satisfy clients’ requirements, service composition is performed to compose the various capabilities of available services. With the proliferation of services having similar functionalities, assessing the quality of a given composition is a paramount factor to decide which services must be selected, or to choose whether a given composition can provide the requested QoS (Quality of Service). However, due to the fluctuating conditions in the dynamic cloud computing environment, the QoS and the performances of the services become unreliable, and therefore call into the question the accuracy of the composition QoS. To tackle this issue, different methods that analyse the QoS have been developed, making it possible to help the designers to first, understand the system behaviour when providers and consumers, are interacting, thus allowing to optimize the system by identifying performance bottlenecks within a specified deployment environment.In this study, the particular problem of many consumers that are competing to acquire services with same functionalities but with different QoS, is considered. For this purpose, assuming a dynamic environment, different models based on Discrete Time Markov Chain are developed to implement several policies of the system. A theoretical modelling of the problem is proposed including analytical results obtained using the Xborne tool. For each model, the average time to reach a given QoS for a community of consumers is reported. Such a performance metric allows the designer to predict the system behaviour in a dynamic environment.

Personalized manufacturing service composition recommendation: combining combinatorial optimization and collaborative filtering

Owing to the rapid proliferation of service technologies in cross-enterprise manufacturing collaborations, manufacturing service composition (MSC) has attracted much attention from both academia and industries. However, the existing service composition is often constructed by the combination of off-line and on-line services, quality of service (QoS) attributes are not appropriate for satisfying the specific demands of MSC. Moreover, there are very few historical QoS invocations of manufacturing service, leading to difficulty in recommending appropriate service composition to a target user. In order to find the personalized MSC mode from a complex service network more accurately, we combine combinatorial optimization with collaborative filtering in this paper to figure out two questions: (1) how to construct a QoS description model of manufacturing service composition; (2) how to enhance the effectiveness of personalized QoS-aware service composition recommendations. First, the new QoS model of MSC is proposed by considering both traditional characteristics (e.g. availability, performance and reliability), variability of service composition and enterprise dimensional QoS attributes. Second, the service combination optimization is constructed based on combinatorial optimization method. Third, the collaborative filtering is employed to calculate the missing QoS values of the candidate manufacturing services. Finally, with both available objective functions and predicted QoS values, optimal service composition recommendation can be generated by using combinatorial optimization model with QoS constraints.

How to select dynamically a QoS-driven composite web service by a multi-agent system using CBR method

Service-oriented architecture permits the composition of web services provided with different Quality of Service (QoS) levels. In a given composition, finding the set of services that optimises some QoS attributes under its constraints is a problem that needs to be solved. Our aim is to propose an intelligent approach to the selection of a Composite Web Service (CWS) based on QoS. This paper reports the authors’ recent research on addressing the issue. An overview on the previously proposed approaches is presented. These approaches correspond to several improvements of an existing multi-agent one, which is well-cited in the specialised literature. Each framework, implemented on JADE (Java Agent Development) framework, improves another one in terms of CPU time and/or QoS score, to reach a new agent-based and scalable framework. The last framework utilises the agents’ ability of negotiation, interaction and cooperation in order to facilitate the selection of composite web services. By using CBR method, the agents can memorise QoS scores and availability. The improvements are related not only to the CPU time but also to the Composite QoS (CQoS) value, while operating in a dynamic environment and taking into account user preferences.

Research on Web Service Composition Algorithm Using Description Logic

This paper presents a dynamic Web service composition algorithm based on description logic. Firstly, each input or output of the Web service request is regarded as a concept of description logic and according to the semantic similarity between concepts given the five types of description logic, we study on the dynamic composition algorithm based on service. Because the factors of service semantics and quality of service composition are considered, the algorithm can automatically implement dynamic composition according to the user's service request. Because of using the expression ability of semantic description logic, when Web service is combined the algorithm can determine whether the service can be combined according to the semantic relationship between concepts, thus the probability of successful combination can be improved. DOI : http://dx.doi.org/10.11591/telkomnika.v12i1.3536

WS-SIM: A Toolkit for Modeling and Simulation of Service Composition

Web service has been rapidly developed in recent years. Web service selection is an important issue in web service composition and lots of service selection algorithms have been presented. As lots of them select an atomic service during runtime, it is not an easy task to evaluate the quality of the composited service which composed of several atomic services. In this work we introduce WS-SIM, a simulation toolkit, to solve this problem. WS-SIM supports modeling and simulating composite services and atomic services in the real world. This system also provides many common service selection algorithms and researchers can custom their own service selection algorithm for a simulation experiment. The quality of composite services can also be generated by our system. Furthermore, to demonstrate suitability of the WS-SIM, in this paper, functionalities of our system are illustrated by a case study. This confirms the usability and the applicability of WS-SIM.

QoS-aware web service selection with negative selection algorithm

Web service selection, as an important part of web service composition, has direct influence on the quality of composite service. Many works have been carried out to find the efficient algorithms for quality of service (QoS)-aware service selection problem in recent years. In this paper, a negative selection immune algorithm (NSA) is proposed, and as far as we know, this is the first time that NSA is introduced into web service selection problem. Domain terms and operations of NSA are firstly redefined in this paper aiming at QoS-aware service selection problem. NSA is then constructed to demonstrate how to use negative selection principle to solve this question. Thirdly, an inconsistent analysis between local exploitation and global planning is presented, through which a local alteration of a composite service scheme can transfer to the global exploration correctly. It is a general adjusting method and independent to algorithms. Finally, extensive experimental results illustrate that NSA, especially for NSA with consistency weights adjusting strategy (NSA+), significantly outperforms particle swarm optimization and clonal selection algorithm for QoS-aware service selection problem. The superiority of NSA+ over others is more and more evident with the increase of component tasks and related candidate services.

An Approach to Composite QoS Parameter based Web Service Selection

In any enterprise application Quality of Service (QoS) is an important attribute for selecting a service during the service composition process. Although availability and reliability have been considered as the predominant factors for estimating reputation, two aspects are lacking in the literature. First, their use is limited to composite service level and does not count at the atomic level. Second, their combined effect is not evaluated. Hence, the methodology of estimating reputation and its use for atomic service will have compounding effect on the overall quality of the composite service. We feel, better estimation of QoS can be done with both factors considered together on the simple premise that availability tells about only the probability of that service being up/running, but doesnot tell about its failure trend. In our work we present mathematical modelling of these predominant QoS factors using Markov model and Weibull analysis. A scenario has been simulated using Colored Petri Nets (CPN) to study the behavioral aspects. The outcome of our research is two fold. First, counting on probability of a service being up/running and its failure trend, together, results in a better estimation of its behavior and helps selecting the most appropriate one. Second, this resulted in selection of a service with higher reputation but lower usage cost, as opposed to using a single factor that resulted in higher reputation with higher cost.

A Survey on Workflow Verifications of Petri Nets based Service Process Management

Service process management is a cross-discipline research topic, including computer science, management technology and economics. How to effectively integrate service resources to meet customer demands becomes a key problem to service-oriented software development. Most of existing works are in the early research stage. The scope of process management consists of process design, process execution, process mining, and process intelligence. However, it requires process modeling, which is a crucial precondition in the lifecycle of service process management. In this paper, it reviews workflow verifications of Petri Nets based service process management. First, the workflow and description supporting tools are introduced. Then, considering the composite service is an effective way to organize third-party business functions seamlessly, the Petri Nets based service workflow employed to formalizing composition behaviors is discussed. Third, components encapsulated in the composite service may be encountered functional and non-functional problems since services are offered by different organizations. The functional verification includes the correctness, reachability and safety. The non-functional verification is to evaluate the performance of Petri Nets based workflow model ranging over timed constraints and probabilistic behaviors. Therefore, it summarizes Petri Nets based workflow verification techniques to guarantee the quality of services composition. In conclusion, this survey provides academic references to researchers and developers in service computing and process management.

Quality of service-based multi-domain routing under multiple quality of service metrics

Applications such as voice and video require network paths that satisfy several different quality of service (QoS) metrics, such as delay, jitter, packet loss rate and availability. The calculation of paths under multiple QoS metrics, such as the above four metrics, is a difficult problem since these metrics are in general incompatible. The authors propose a simple method for combining the above four QoS metrics into a single composite QoS metric which can be used as a link cost in Dijkstra's algorithm in order to calculate a path. The authors evaluated the proposed method in a multi-domain routing environment where domain reachability information is available through a service oriented architecture paradigm, and they show that it outperforms two commonly used methods. The results are also applicable to routing within a single domain.

Research on Web service selection based on cooperative evolution

Web service selection, as an important part of Web service composition, has direct influence on the quality of composite service. Therefore, it has attracted many researchers to focus on the research of quality of service (QoS) driven Web service selection in the past years, and many algorithms based on integer programming (IP), mixed integer linear programming (MILP), multi-dimension multi-choice 0–1 knapsack problem (MMKP), Markov decision programming (MDP), genetic algorithm (GA), and particle swarm optimization (PSO) and so on, have been presented to solve it, respectively. However, these results have not been satisfied at all yet. In this paper, a new cooperative evolution (Co-evolution) algorithm consists of stochastic particle swarm optimization (SPSO) and simulated annealing (SA) is presented to solve the Web service selection problem (WSSP). Furthermore, in view of the practical Web service composition requirements, an algorithm used to resolve the service selection with multi-objective and QoS global optimization is presented based on SPSO and the intelligent optimization theory of multi-objective PSO, which can produce a set of Pareto optimal composite services with constraint principles by means of optimizing various objective functions simultaneously. Experimental results show that Co-evolution algorithm owns better global convergence ability with faster convergence speed. Meanwhile, multi-objective SPSO is both feasible and efficient.

A Large-Scale Device Collaboration Resource Selection Method with Multi-QoS Constraint Supported

With the rapid development of the “Internet of Things” and large-scale area management, device collaboration has developed to the stage of large-scale device collaboration. Aiming at the large-scale, dynamics and real-time of the large-scale device collaboration system, in order to ensure the performance of the large-scale device collaboration system, a Quality of Service(QoS) model of large-scale device collaboration is proposed, which contains device QoS model, composite QoS model and QoS relation model. Based on the model, an algorithm of the resource selection in large-scale device collaboration system is presented. Finally, the result of simulation experiments on the large-scale device collaboration prototype system shows that the method can satisfy the performance requirements of the large-scale device collaboration system.

TESTING AND FORMAL VERIFICATION OF SERVICE ORIENTED ARCHITECTURES

We examine two open engineering problems in the area of testing and formal verification of internet-enabled service oriented architectures (SOA). The first involves deciding when to formally and exhaustively verify versus when to informally and non-exhaustively test. The second concerns scalability limitations associated with formal verification, to which we propose a semi-formal technique that uses software agents. Finally, we assess how these findings can improve current software quality assurance practices. Addressing the first problem, we present and explain two classes of tradeoffs. External tradeoffs between assurance, performance, and flexibility are determined by the business needs of each application, whether it be in engineering, commerce, or entertainment. Internal tradeoffs between assurance, scale, and level of detail involve the technical challenges of feasibly verifying or testing an SOA. To help decide whether to exhaustively verify or non-exhaustively test, we present and explain these two classes of tradeoffs. Identifying a middle ground between testing and verification, we propose using software agents to simulate services in a composition. Technologically, this approach has the advantage of assuring the quality of compositions that are too large to exhaustively verify. Operationally, it supports testing these compositions in the laboratory without access to source code or use of network resources of third-party services. We identify and exploit the structural similarities between agents and services, examining how doing so can assure the quality of service compositions.

Composite quality of service and decision making perspectives in wireless networks

Supporting quality of service (QoS) in wireless networks has been a very rich and interesting area of research. Many significant advances have been made in supporting QoS in single wireless networks. However, the support for the QoS across multiple heterogeneous wireless networks will be required in the future wireless networks. In connections spanning multiple wireless networks, the end-to-end QoS will depend on several factors such as mobility and connection patterns of users, and the QoS policies in each of the wireless networks. The end-to-end QoS is also affected by multiple decisions that must be made by several different network entities for resource allocation. The paper has two objectives: one is to demonstrate the decision making process for resource allocation in multiple heterogeneous wireless networks and the second is to present a novel concept of composite QoS in such wireless environment. More specifically, we present an architecture for multiple heterogeneous wireless networks, decision making process for resource request and allocation, a simulation model to study composite QoS, and several interesting results. We also present potential implications of composite QoS on users and network service providers. We also show how the QoS ideas presented in this paper can be used by wireless carriers for improved QoS support and management. The paper can form the basis for a significant further research in DSS for emerging 3G/4G wireless networks supporting QoS for a range of sophisticated and resource intensive mobile applications.