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Adaptation is an important concern in cloud-based applications composed of services provided by different cloud providers since cloud services can suffer from Quality of Services(QoS) fluctuations. Other conditions that can also trigger an adaptation process at runtime are the unavailability of services or the violation of user-defined policies. Moreover, the detection and reaction on such changes...
Availability is an important metric to measure the quality of service (QoS) in a resilience network. It can usually be provided by using protection, either shared or dedicated. On the other hand, there is a trade-off between guaranteeing availability and resource efficiency usage in the network. In this study, we propose an algorithm that jointly considers availability and resource efficiency in an...
In recent years, cloud storage providers have gained popularity for personal and organizational data, and provided highly reliable, scalable and flexible resources to cloud users. Although cloud providers bring advantages to their users, most cloud providers suffer outages from time-to-time. Therefore, relying on a single cloud storage services threatens service availability of cloud users. We believe...
Network reliability and survivability are important features for hosting high-demanding services in virtual network environments. Since multiple virtual networks can share the physical resources of the underlying substrate, even a single failure in the substrate can affect a large number of virtual networks and the services they offer. To overcome the physical link failure impact on virtual network...
As the underlying core infrastructure and important component of cloud computing, distributed storage system is the foundation of all kinds of cloud services. While its replica mechanism enhanced the reliability and performance of system, the extra block replicas consume more disk space and maintenance cost significantly increased too. In this paper, we propose a novel QoS-aware Dynamic Data Replicas...
Due to the possibility of internal changes of services or changes in their environment, dynamic service substitution has become a key problem in Service Oriented Architecture (SOA). In recent years, researchers have worked out several algorithms for dynamic service substitution. However, the performance of these algorithms is generally not that satisfactory. In this paper, we propose a heuristic service...
To ensure that consumer requests for web services are served successfully and effectively amidst overwhelming options, one must narrow the web service search to only the most qualified, highest-ranked services. However, today, the ranking of services is done only with regards to static attributes or with a snapshot of current values, resulting in low quality search results. To improve user experience,...
Dynamic reconfiguration can help SOA based applications to update, modify, add and remove their functions, improve their performance, enhance their reliabilities and robustness. However few works focus on the QoS-based dynamic reconfiguration of SOA-based applications. This paper presents an approach for QoS-based dynamic reconfiguration of SOA based applications. The proposed approach can reconfigure...
Geographic Information System (GIS) is a system that stores, analyzes and handles any spatially referenced data. Recently, GIS has got a lot of attention from both research and industry communities. It is a fast growing technology in the world. Similarly, Web services also play major role in the software industry where web services are the pieces of software components, which are distributed over...
Large-scale distributed computing systems (LDCSs) can be best characterized by their dynamic nature particularly in terms of availability and performance. Typically, these systems deal with various types of jobs in many aspects, such as resource requirements, quality of service (QoS) and other temporal constraints. These diverse characteristics in both resources and jobs impose a great burden on scheduling...
The objective of web services selection is to maximize an application-specific utility function under the end-to-end QoS constraints. Existing methods can be divided into two types: local selection method and global selection method. The local selection method is simple and efficient, but can not meet the end-to-end QoS constraints. The global selection method can satisfy the global QoS constraints,...
We present an optimization approach for service compositions in large-scale service-oriented systems that are subject to Quality of Service (QoS) constraints. In particular, we leverage a composition model that allows a flexible specification of QoS constraints by using constraint hierarchies. We propose an extensible met heuristic framework for optimizing such compositions. It provides coherent implementation...
Service Oriented Architectures enable markets of functionally equivalent service providers delivering services at different Quality of Service (QoS) and cost levels. Under these circumstances, there is a need for mechanisms to optimally select service providers at run-time to support a business process execution so that a utility function for the business process is maximized subject to QoS and cost...
Service-oriented architecture (SOA) provides a scalable and flexible framework for service composition. Service composition algorithms play an important role in selecting services from different providers to reach desirable QoS levels according to the performance requirements of composite services, and improve customer satisfaction. This paper proposes a novel QoS-based dynamic service composition...
This paper presents a novel shared mesh restoration scheme for survivable multilayered networks with Shared Risk Link Groups (SRLG) considerations. We develop a heuristic restoration scheme called Two-Step Partial Protection Risk Algorithm to tackle three major problems: (1) network survivability (2) optimization of spare bandwidth, and (3) offering differentiated classes of service. The proposed...
Web services high availability becomes an important challenge these last years, especially for critical systems. Traditional solutions to achieve availability are mostly based on replication. Another more recent approach consists of using Web services communities. A community is a group of different Web services with similar functionalities. So, the high availability of a Web service is ensured by...
In this paper, a novel data burst assembly algorithm which based on control channel availability and traffic type is presented. In this mechanism, a burst is created only if its control packet can be transmitted and can be packed as different length according to traffic type to adapt the network requirement best dynamically. The variable Lstep which defined as the variation of the size threshold,...
Data availability and accessing performance in distributed storage network have become more and more important. For this reason, we propose an adaptive replica creation algorithm with fault tolerance in the distributed storage network. This algorithm will be to maintain a rational replica number, not only satisfying the user anticipant availability, improving access efficiency and balancing overload,...
With the popularity of service-oriented computing, how to construct highly available service-oriented applications is becoming a hot topic in both the research and industry communities. As a fundamental problem in dynamic service selection, availability estimation is challenging because of the dynamic nature of Web services. To grasp the dynamic nature of Web services, we set up an experimental environment...
This paper will present a novel survivable routing method for circuit switched mesh networks, which aim to guarantee a pre-defined end-to-end availability for each connection. The proposed method is based on the traditional dedicated protection concept. However, the widely installed dedicated path protection often comes up against topological bounds and is not able to guarantee a certain level of...
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