A complex infrastructure is usually a reality in a virtual enterprise. For these enterprises to operate well they would need notions of workflows, global and local business processes, Service Level Agreements, and business transactions. Web Service Standards such as SOAP, WSDL, and BPEL4WS make virtual enterprise increasingly practical, speeding up the flow of business and reducing costs. These web services have to be interfaced with the internal business processes. The interchange of service results in the interaction of existing business processes and results in new distributed processes.

技術解説 IEEE Internet Computing

Currently, a large number of smart objects and different types of devices are interconnected and communicate via Internet Protocol that creates a worldwide ubiquitous and pervasive network called the Internet of Things (IoT). With an increase in the deployment of smart objects, IoT is expected to have a significant impact on human life in the near future. A majorbreakthrough in bridging the gap between virtual and physical worlds came from the vision of the Web of Things (WoT), which employs open Web standards in achieving information sharing and objects interoperability. Social Web of Things (SWoT) further extends WoT to integrate smart objects with social networks and is observed to not only bridge between physical and virtual worlds but also facilitate continued interaction between physical devices and human. This makes SWoT the most promising approach and has now become an active research area.This survey introduces necessary background and fundamentals to understand current efforts in IoT, WoT and SWoT by reviewing key enabling technologies. These efforts are investigated in detail from several different perspectives such as architecture design, middleware, platform, systems implementation, and application in hand. Moreover, a large number of platforms and applications are analyzed and evaluated from various alternatives have become popular during the past decade. Finally, we address associated challenges and highlight potential research to be perused in future.

Choices for interaction with things on Internet and underlying issues

Overview of the MPEG-4 Standard and Error Resilience Investigations

Content delivery networks (CDNs) have gained immense popularity over the years. Replica server placement is a key design issue in CDNs. It entails placing replica servers at meticulous locations, such that cost is minimized and quality of service of end-users is satisfied. Many replica server placement models have been proposed in the literature of traditional CDN. As the CDN architecture is evolving through the adoption of emerging paradigms, such as, cloud computing and network functions virtualization, new algorithms are being proposed. In this paper, we present a comprehensive survey of replica server placement algorithms in traditional and emerging paradigm-based CDNs. We categorize the algorithms and provide a summary of their characteristics. Besides, we identify requirements for an efficient replica server placement algorithm and perform a comparison in the light of the requirements. Finally, we discuss potential avenues for further research in replica server placement in CDNs.

A Survey on Replica Server Placement Algorithms for Content Delivery Networks

Cloud computing has gained significant attention of industry and academic sectors which are interested in adopting or experimenting with this technology. An increasing number of companies are expected to migrate their systems to cloud enabled infrastructures. However, there has not been much attention paid to provide sufficient process support. Since migration projects are likely to encounter several kinds of challenges, it is important to identify and share the process and logistical requirements of migration projects in order to build a body of knowledge of appropriate process, methods, and tools. This paper purports to contribute to the growing knowledge of how to migrate existing systems to cloud computing by reporting our effort aimed at migrating an Open Source Software (OSS) framework, Hackystat, to cloud computing. We report the main steps followed, the process and technical challenges faced, and some of the strategies that helped us to address those challenges. We expect the reported experiences can provide readers with useful insights into the process and technical aspects that should be considered when migrating existing software systems to cloud computing infrastructures.

Migrating Service-Oriented System to Cloud Computing: An Experience Report

Adaptation in multimedia systems is usually restricted to defensive, reactive media adaptation (often called stream-level adaptation). We argue that offensive, proactive, system-level adaptation deserves not less attention. If a distributed multimedia system cares for overall, end-to-end quality of service then it should provide a meaningful combination of both. We introduce an adaptive multimedia server (ADMS) and a supporting middleware which implement offensive adaptation based on a lean, flexible architecture. The measured costs and benefits of the offensive adaptation process are presented. We introduce an intelligent video proxy (QBIX), which implements defensive adaptation. The cost/benefit measurements of QBIX are presented elsewhere (1). We show the benefits of the integration of QBIX in ADMS. Offensive adaptation is used to find an optimal, user-friendly configuration dynamically for ADMS, and defensive adaptation is added to take usage environment (network and terminal) constraints into account.

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Offensive and Defensive Adaptation in Distributed Multimedia Systems

Multimedia services typically need not only huge resources but also a fairly stable level of Quality of Services. This requires server architectures that enable continuous adaptation. The Adaptive Distributed Multimedia Server (ADMS) of the University Klagenfurt is able to dynamically add and remove nodes to the actual configuration, thus realizing the offensive adaptation approach.

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Placement of Nodes in an Adaptive Distributed Multimedia Server

The purpose of this paper is to present a new infrastructure for multimedia database searches based on CORBA and mobile agent technology. A new mobile agent system, called Vagabond, was implemented in pure Java using only standard CORBA facilities. The fundamental agent design and architecture is introduced. Measurements demonstrated the merits of Vagabond, namely the simple design, the implicit heterogeneity inherited from CORBA, and its speed. The system (renamed as M/sup 3/) was implanted inside an Oracle8i database system which is able to run Java code as a stored procedure. Further measurements have justified the idea presented above, ie. sending agents directly inside the database can decrease the response time of multimedia content search and retrieval. However, the required modifications made the embedded agency accessible for clients using only Aurora, Oracle's modified Visi-broker ORB. On the basis of the Proxy design pattern, the paper presents a proxy solution that encapsulates the specific protocol issues that restricted interoperability, and thus provides the user of the infrastructure with the benefits of a truly heterogeneous environment.

Mobile agents in a distributed heterogeneous database system

Web services provide distributed communication in a platform independent way. The WS-* standards define how middleware aspects (security, reliability, transactions, etc.) can be realized through web services. Although the WS-Policy standard family can be used to configure the various WS-* protocols, they are very hard to construct and to maintain manually. In addition, most SOA products and Grid systems implementing these standards provide their own methods for configuring these protocols, making it very difficult to match the various configuration options of different products. This fact inspired us to propose a platform independent metamodel for describing distributed systems of web services including the most important WS-* standards. The present article defines the full metamodel, it specifies the corresponding programming language formally, and it shows the productivity of the framework built around the metamodel through real-life examples. The framework is capable of generating product specific configuration files and source codes, resulting in directly interoperable applications even between different SOA products. The framework could also promote interoperability with Grid systems built on WS-* protocols.

A Metamodel for the Web Services Standards

The basic building blocks of SOA systems are web services. WSDL, the standard language for defining web services, is far too complex and redundant to be efficiently handled by humans. Existing solutions use either graphical representations (UML, etc.), which are again inefficient in large scale projects, or define web services in the implementation’s native language, which is a bottom-up approach risking interface stability. Both lack support for concepts like conditions, access-rights, etc. The domain specific language introduced in this paper uses a Java and C#-like language for describing web service interfaces. It has the same descriptive power as WSDL while maintaining simplicity and readability. Examples show how to use the language, and how it can be compiled into WSDL.

Balázs Goldschmidt

Papers

Offensive and Defensive Adaptation in Distributed Multimedia Systems

Placement of Nodes in an Adaptive Distributed Multimedia Server

Mobile agents in a distributed heterogeneous database system

A Metamodel for the Web Services Standards

A Human Readable Platform Independent Domain Specific Language for BPEL