In spite of the progress made in the past decade, the quality-of-services (QoS) of the video-conferencing (VC) systems involving four or more sites need to be improved much further in order to attract a large number o...
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In spite of the progress made in the past decade, the quality-of-services (QoS) of the video-conferencing (VC) systems involving four or more sites need to be improved much further in order to attract a large number of users. One of the key issues in enabling high-level QoS in multi-party (MP) VC systems is the accurate maintenance of the temporal relationship among media units (MUs) from creation to play while keeping the MU delivery delays within acceptable bounds. Unlike the case of two-party video-conferencing, MP VC requires multiple media streams to be delivered to multiple sites with a high degree of synchrony. In this paper, an MP VC system model called the SB-VC system in which a global-time-based synchronization approach called the target play time (TPT) scheme is used is presented. The TPT scheme is highly effective in achieving high-precision intra-stream, inter-stream, and inter-destination synchronizations in MP VC. As a validation, a prototype SB-VC system has been constructed by use of the time-triggered Message-triggered object (TMO) specification and programming scheme and its tool-kit. Its performance is compared against that of an advanced research prototype developed by Microsoft, ConferenceXP, and the results demonstrate that the SB-VC system is a promising model for realizing next-generation VC systems that offer QoSs significantly better than those of current-generation VC systems.
A wide range of high-performance distributed embedded systems have been designed and deployed. Physically distributed embedded systems are used for manufacturing and control, traffic analysis, and other problems. Inte...
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ISBN:
(纸本)9780769531328
A wide range of high-performance distributed embedded systems have been designed and deployed. Physically distributed embedded systems are used for manufacturing and control, traffic analysis, and other problems. Interestingly, today's systems-on-chips are sufficiently complex that they must be treated as distributed embedded systems. At all scales of physical extent, middleware is required to manage the computations. This paper looks at distributed embedded systems at several physical scales and considers the types of middleware that are needed to operate these systems.
The performance of autonomous vehicles could be drastically improved if ad-hoc networking and suitable real-time coordination is employed to optimize and improve the joint behavior of multiple autonomous units. Howeve...
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ISBN:
(纸本)9780769531328
The performance of autonomous vehicles could be drastically improved if ad-hoc networking and suitable real-time coordination is employed to optimize and improve the joint behavior of multiple autonomous units. However, due to ad-hoc connections and the real-time interaction the correctness and safety of such coordinated autonomous units is very hard to ensure. In this paper we present how service-orientedreal-time coordination can be employed to achieve this goal. Based on the proper real-time coordination between two or more vehicles captured by a service contract, we focus on structural changes and the instantiation and termination of service contracts which is a crucial prerequisite for a safe system operation. We present how the structural changes and the service contract creation/deletion can be modeled by a well-defined UML subset consisting of class and object diagrams with collaborations as well as well-defined behavioral rules can be verified taking the dynamic structural changes due to the ad-hoc networking as well as the real-time coordination into account. The new verification technique is outlined and the application of the technique for an application example is presented.
In this paper, we describe a XML based profile for modeling the semantics of realtime systems. We aim to use realtime Markup Language (RTML) to provide a comprehensive description of temporal properties for the use ...
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ISBN:
(纸本)9780769531328
In this paper, we describe a XML based profile for modeling the semantics of realtime systems. We aim to use realtime Markup Language (RTML) to provide a comprehensive description of temporal properties for the use in distributed systems communication. RTML is derived from a number of specifications including OMG UML Profile in Schedulability, Performance, and time. In this paper, we discuss the technique that was used to develop RTML semantic model and the important concepts in RTML.
This paper discusses the benefits of exploiting 1) the principle of global-time-based coordination of distributedcomputing actions (TCoDA) and 2) a high-level component-/object-based programming approach in developin...
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ISBN:
(纸本)9780769531328
This paper discusses the benefits of exploiting 1) the principle of global-time-based coordination of distributedcomputing actions (TCoDA) and 2) a high-level component-/object-based programming approach in developing real-time embedded computing software. The benefits are discussed in the context of a concrete case study. A new major type of distributed multimedia processing applications, called Adaptive distributed Sound Systems (ADSSs), is presented here to show the compelling nature of the TCoDA exploitation. High-quality ADSSs impose stringent real-timedistributedcomputing requirements. They require a global-time base with precision better than 100 mu s. For efficient implementation, the TMO programming scheme and associated tools are shown to be highly useful. In addition, a prototype TMO-based ADSS has been developed and its most important quality attributes have been empirically evaluated. The prototype ADSS has also turned out to be a cost-effective tool for assessing the quality of service of a TMO execution engine.
This paper proposes a new approach to teach the STEM (Science, Technology, Engineering, and Mathematics) knowledge informally via robotic games. In this approach, a robotic playground is built to provide a hands-on pr...
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ISBN:
(纸本)9780769531328
This paper proposes a new approach to teach the STEM (Science, Technology, Engineering, and Mathematics) knowledge informally via robotic games. In this approach, a robotic playground is built to provide a hands-on programming and playing experience with robots controlled by service-orientedcomputing (SOC) software, which is based on a new approach that uses reusable services (components) with standard interfaces and platform-independent interoperability. services in the repository are annotated with STEM knowledge to enforce the required contents. In this way, students can learn computing and STEM in an entertaining manner. l
Grid computing has emerged as a new paradigm of distributedcomputing technology on large-scale resource sharing and coordinated problem solving. Based on a proposed Web service-based grid architecture, we have design...
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ISBN:
(纸本)9780769531328
Grid computing has emerged as a new paradigm of distributedcomputing technology on large-scale resource sharing and coordinated problem solving. Based on a proposed Web service-based grid architecture, we have designed a service grid middleware system called CROWN which aims to promote the utilization of valuable resources and cooperation of researchers nationwide and world-wide. To address the issues of CROWN resource management, we proposed some key technologies including trustworthy remote and hot service deployment, overlay-based distributed resource organization, resource scheduling and load balance, and federation-based virtual organization management. A status of the wide-area CROWN testbed is also introduced in this paper. Three typical applications including AREM, MDP and gViz are deployed on the CROWN testbed. Experience of CROWN testbed deployment and application development shows that the middleware can support the typical scenarios such as computing-intensive applications and data-intensive applications etc.
Currently the developing process for enterprise applications is improved by the serviceoriented Architecture (SOA) paradigms. With SOAs the creation of modular and clearly defined software architectures at a high gra...
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ISBN:
(纸本)9780769531328
Currently the developing process for enterprise applications is improved by the serviceoriented Architecture (SOA) paradigms. With SOAs the creation of modular and clearly defined software architectures at a high grade of interoperability and reusability is possible. For resourceconstraint networked devices the Devices Profile for Web services (DPWS) specification adapt the SOA paradigms to create a framework for interoperable and standardized communication between embedded devices. This paper explains how special parts of DPWS can be adapted to provide real-time capabilities. So this paper shows how developers of real-time software can use the advantages of Web services and which adaptations are necessary to create Web services with real-time capabilities.
Recent advances in software processes and artifacts for automating middleware configurations in distributedreal-time and embedded (DRE) systems are starting to address the complexities faced by system developers in d...
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ISBN:
(纸本)9780769531328
Recent advances in software processes and artifacts for automating middleware configurations in distributedreal-time and embedded (DRE) systems are starting to address the complexities faced by system developers in dealing with the flexibility and configurability provided by contemporary middleware. Despite the benefits of these new processes, there remain significant challenges in verifying their correctness, and validating their effectiveness in meeting the end-to-end quality of service (QoS) requirements of DRE systems. This paper addresses this problem by describing how model-checking and structural correspondence can be used to verify the correctness of a middleware QoS configuration process that uses model-based graph transformations at its core. Next, it provides empirical proof to validate the effectiveness of our technique to meet the end-to-end QoS requirements in the context of a representative DRE system.
In this paper, a Role-based Access Control (RBAC) model is applied and extended to a multimedia version called Multi-Role Based Access Control (MRBAC), which can fully support the comprehensive and multilevel security...
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ISBN:
(纸本)9780769531328
In this paper, a Role-based Access Control (RBAC) model is applied and extended to a multimedia version called Multi-Role Based Access Control (MRBAC), which can fully support the comprehensive and multilevel security control requirements of the distributed multimedia applications. The object-oriented concept is adopted in MRBAC to perform the hybrid role hierarchy management and security roles and rules administration. In summary, MRBAC can: 1) support the multi-level security protection for multimedia data;2) provide access control by checking both the time constrains and IP addresses;and 3) decentralize the administration functions to make the access control management more efficient.
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