Reasoning on infeasibility in distributed collaborative computing environment

Collaborative computing is a new communication technology that makes it possible to extend model formulation, management, and analysis into a geographically distributed group environment. The forms of communication may vary from asynchronous hypermedia teamwork via the Internet to multipoint desktop video conferencing. The latter presents the maximal potential for integrating shared quantitative model analysis with real-time/asynchronous geographically distributed electronic meetings. Infeasibility diagnosis and reasoning on conflict resolution are known to be important parts of an evolving approach to linear programming model analysis. In the new distributed environment, several specific decision support issues related to infeasibility analysis emerge. One is the learning mechanism for capturing group knowledge on infeasibility resolution that is generated during the collaborative sessions of model analysis. The other new decision support component is a coordination protocol that is capable of linking individual activities and software transactions for the support of group reasoning on infeasibility analysis. This paper addresses these issues on the basis of committee models for infeasibility resolution and the neural network approach. Examples of modeling cases are based on experiments using a multiple criteria model for support of resource allocation in a distributed electronic meeting, and the case of model-based diagnosis that the group is involved in.     

Sharing VLNET worlds on the Web

Virtual environments define a new interface for networked multimedia applications. The sense of “presence” in the virtual environment is an important requirement for collaborative activities involving multiple remote users working with social interactions. Using virtual actors within the shared environment is a supporting tool for presence. In this paper, we present a shared virtual life network with virtual humans that provides a natural interface for collaborative working and we describe the bridge we realized between this 3D shared world and the Web through a system of 3D snapshots.     

MediaWeaver—A Distributed Media Authoring System for Networked Scholarly Workspaces

We describe MediaWeaver—a software framework for composing distributed media in the context of university research and instruction. Authors compose networked media, software tools and mediastreams, and can freely annotate media by media of any form using schema of their own design. Faculty and student authors compose distributed media using common Macintosh, World Wide Web and NeXTSTEP applications, supported by services from UNIX workstations.The MediaWeaver system mediates between network multimedia services and interface kits with which novice programmers and non-programmers may easily create radically different interactive views into shared mediabases. The network services include search engine abstractions, filters, relational modeling frameworks.MediaWeaver has supported collaborative projects in history, drama, music, art, anthropology, environmental studies, and other fields since 1993. Applications range from traditional relational text databases and indexed HTML WWW sites to course readers, research archives, journals and seminar spaces.     

Monitoring and debugging distributed realtime programs

In this paper we describe the design and implementation of an integrated monitoring and debugging system for a distributed real-time computer system. The monitor provides continuous, transparent monitoring capabilities throughout a real-time system's lifecycle with bounded, minimal, predictable interference by using software support. The monitor is flexible enough to observe both high-level events that are operating system- and application-specific, as well as low-level events such as shared variable references. We present a novel approach to monitoring shared variable references that provides transparent monitoring with low overhead. The monitor is designed to support tasks such as debugging realtime applications, aiding real-time task scheduling, and measuring system performance. Since debugging distributed real-time applications is particularly difficult, we describe how the monitor can be used to debug distributed and parallel applications by deterministic execution replay.     

动态上下文环境下的实时分布式多媒体系统框架

伴随着多媒体采集和处理设备成本的不断降低,以及处理目标的不断复杂化,多媒体信息系统正朝着大规模数据分析和管理系统靠拢,因此如何有效支持实时分布式多媒体信息所需的实时采集、压缩、传输、处理、描述、反馈与存档,以及后期的浏览与检索,已经成为多媒体计算研究的重要问题。为了有效支持实时分布式多媒体信息的实时采集、传输、处理、描述、存档等的需要,在分析动态上下文环境下实时分布式多媒体系统对底层采集、压缩和传输以及信息的表达和存储的普遍需求的基础上,提出并实现了一个通用的实时分布式媒体信息处理框架,以便为实时分布多媒体系统提供基础服务支持。该框架包括软件平台和信息系统两部分。前者用于将逻辑功能与物理设备隔离开来,完成实时采集、压缩、传输和解压等功能;后者通过统一信息表达格式,将数据与特定的采集处理模块隔离开来,同时还提供了信息管理的功能,以便于用户后期检索。这两部分共同将多媒体系统所需要的实时采集、处理、压缩、描述、反馈与存档以及离线浏览与检索等服务融入一致、统一的框架中。基于该框架的会议系统的相关实验表明,该框架具有良好的开放性、可配置性和可扩展性。     

An intelligent memory caching architecture for data-intensive multimedia applications

With the rapid developments in cloud computing and mobile networks, multimedia content can be accessed conveniently. Recently, some novel intelligent caching-based approaches have been proposed to improve the memory architectures for multimedia applications. These applications often face bottleneck related challenges which result in performance degradation and service delay issues. Intelligent multimedia network applications access the shared data by using a specific network file system. This results in answering the processing related constraints on hard-drive storage and might result in bringing bottleneck issues. Therefore, to improve the performance of these multimedia network applications, we present an intelligent distributed memory caching system. We integrate the multimedia application message passing interface in a multi-threaded environment and propose an algorithm which can handle concurrent response behavior for different multimedia applications. Results demonstrate that our proposed scheme outperforms traditional approaches in terms of throughput and file read access features.

     

Immersive Whiteboard Collaborative System

An immersive whiteboard system is presented where users at multiple locations can communicate with each other. The system features a virtual environment with vivid avatars, stroke compression and streaming technology to effectively deliver stroke data across meeting participants, friendly human interaction and navigation, virtual and physical whiteboard. The whiteboard is both a physical platform for our input/output interfaces and a virtual screen for sharing common multimedia. It is this whiteboard correspondence that allows the user to physically write on the virtual whiteboard. In addition to drawing on the shared virtual board, the immersive whiteboard in our setup permits users to control the application menus, insert multimedia objects into the world, and navigate around the virtual environment. By integrating multimedia objects and avatar representations into an immersive environment, we provide the users with a more transparent medium so that they feel as if they are communicating and interacting face-to-face. The whiteboard efficiently pulls all the collaboration technologies together. The goal of this collaborative system is to provide a convenient environment for participants to interact with each other and support collaborative applications such as instant messaging, distance learning and conferencing.     

A Java framework for Web-based multimedia and collaborativeapplications

MultiTel is a compositional framework for developing collaborative multimedia applications, and also designates a Web-based distributed platform that supports intercomponent communication. This article shows how compositional and coordination paradigms can be successfully applied to design cooperative Java applications with multimedia data exchange. The focus is on multimedia and network architectures, which define generic and specific components coordinated by connectors for resolving the resource management needs of collaborative applications. The MultiTel platform composes application components dynamically, providing mechanisms for building services with plug-and-play transport and multimedia resources     

Integration of manufacturing services into virtual environments over the internet

Virtual reality (VR) is a rapidly developing technology that has a wide spectrum of industrial and commercial applications. Networked (distributed or shared) virtual environments (VE) are of growing interest to modern manufacturing industry; a dominating use of networked virtual manufacturing environments (VMEs) is on-line visualisation and collaborative control of 3D information. This has to be supported by real-time data transfer. To meet a broad range of common requirements for Internet-based VE communications, particularly for virtual manufacturing and collaborative design and control, this paper presents a networked virtual environment system that is designed to support networked virtual design and manufacturing. The system is implemented with manufacturing message specification (MMS) standards so as to integrate a range of manufacturing services into networked VEs over the Internet.     

Maintaining constraints of UML models in distributed collaborative environments

Constraint maintenance plays an important role in keeping the integrity and validity of UML models in embedded software design. While constraint maintenance capabilities are reasonably adequate in existing UML modeling applications, little work has been done to address the distributed constraint maintenance issue in multi-user collaborative modeling environments. The nature of the issue is to maintain constraint consistently across distributed sites in a collaborative modeling environment in the face of concurrency. In this paper, we propose a novel solution to this issue, which can retain the effects of all concurrent modeling operations even though they may cause constraint violations. We further contribute a distributed constraint maintenance framework in which the solution is encapsulated as a generic engine that can be mounted in a variety of single-user UML modeling applications to support collaborative UML modeling and distributed constraint maintenance in embedded software design processes. This framework has been implemented in a prototype distributed collaborative UML modeling application CoRSA.     

Presto—A System Environment for Mission-Critical Multimedia Applications

Summarized in this report is a multiphased R and D program, presto, conducted for developing a multimedia system environment to support a variety of mission-critical applications. The concepts, software design, and system prototype developed during the first phase of the program are presented. In particular, the work on real-time scheduling, multimedia storage and retrieval, and application programming model is described. The major results of the presto Phase I program are a set of new techniques and system software for QoS- and criticality-based, adaptive multiresource management, raw-I/O-based continuous multimedia file management, and data flow-oriented programming with integrated real-time scheduling support.     

Advances in software engineering

Software is the key technology in applications as diverse as accounting, hospital management, aviation, and nuclear power. Application advances in different domains such as these-each with different requirements-have propelled software development from small batch programs to large, real-time programs with multimedia capabilities. To cope, software's enabling technologies have undergone tremendous improvement in hardware, communications, operating systems, compilers, databases, programming languages, and user interfaces, among others. In turn, those improvements have fueled even more advanced applications. Improvements in VLSI technology and multimedia, for example, have resulted in faster, more compact computers that significantly widened the range of software applications. Database and user interface enhancements, on the other hand, have spawned more interactive and collaborative development environments. Such changes have a ripple effect on software development processes as well as on software techniques and tools. In this article, we highlight software development's crucial methods and techniques of the past 30 years     

Integration of humanoid robots in collaborative working environment: a case study on motion generation

This paper illustrates through a practical example an integration of a humanoid robotic architecture, with an open-platform collaborative working environment called BSCW (Be Smart-Cooperate Worldwide). BSCW is primarily designed to advocate a futuristic shared workspace system for humans. We exemplify how a complex robotic system (such as a humanoid robot) can be integrated as a proactive collaborative agent which provides services and interacts with other agents sharing the same collaborative environment workspace. Indeed, the robot is seen as a ‘user’ of the BSCW which is able to handle simple tasks and reports on their achievement status. We emphasis on the importance of using standard software such as CORBA (Common Object Request Broker Architecture) in order to easily build interfaces between several interacting complex software layers, namely from real-time constraints up to basic Internet data exchange.     

Implementation of Distributed Floor Control Protocols on Overlay Networks

Collaborative multimedia applications (CMAs) on overlay networks are gaining popularity among users who are geographically dispersed. Examples of these kinds of applications include networked games and collaborative design and simulation. An important challenge in realizing CMAs is obtaining floor control, a problem in which the end-users compete among themselves to gain exclusive access to a shared resource. In this paper, we present deterministic and randomized distributed mechanisms for solving the floor control problem. In particular, we adapt the well-known MAC protocols viz. distributed queue dual bus (DQDB), ALOHA, and carrier sense multiple access (CSMA) as solutions for the floor control problem. Central to our adaptation is an algorithmic methodology that efficiently virtualizes the underlying network connecting the CMA participants so as to enhance the proposed solutions' performance. We present analytical and experimental studies on the performance of the proposed floor control protocols that bring out their essential characteristics.     

Collaborative Multimedia Presentations in Mobile Environments

Distributed multimedia documents systems, distributed video servers are examples of multimedia presentations involving collaboration among multiple information sources. In such applications, objects have to be retrieved from their sources and presented to users according to specified temporal relationships. Objects retrieval in these collaborative applications is influenced by their presentation times, durations, and network throughput available to their sources. Replication of objects amongst the set of collaborating systems gives a choice for object retrieval. Client going through a multimedia presentation can be in a mobile environment. Here, object retrievals from collaborating servers are carried out by base stations to which the client is attached. Mobile client then downloads objects from the base station.In this paper, we present a graph-search based algorithm for computing and negotiating throughput requirements of collaborating multimedia presentations with replicated objects in a mobile environment. This algorithm maximizes the number of cached objects (that have already been played) for handling operations such as reverse presentation.     

Collaborative telemedicine for interactive multiuser segmentation of volumetric medical images

Telemedicine has evolved rapidly in recent years to enable unprecedented access to digital medical data, such as with networked image distribution/sharing and online (distant) collaborative diagnosis, largely due to the advances in telecommunication and multimedia technologies. However, interactive collaboration systems which control editing of an object among multiple users are often limited to a simple “locking” mechanism based on a conventional client/server architecture, where only one user edits the object which is located in a specific server, while all other users become viewers. Such systems fail to provide the needs of a modern day telemedicine applications that demand simultaneous editing of the medical data distributed in diverse local sites. In this study, we introduce a novel system for telemedicine applications, with its application to an interactive segmentation of volumetric medical images. We innovate by proposing a collaborative mechanism with a scalable data sharing architecture which makes users interactively edit on a single shared image scattered in local sites, thus enabling collaborative editing for, e.g., collaborative diagnosis, teaching, and training. We demonstrate our collaborative telemedicine mechanism with a prototype image editing system developed and evaluated with a user case study. Our result suggests that the ability for collaborative editing in a telemedicine context can be of great benefit and hold promising potential for further research.     

JASMINE: A Java Tool for Multimedia Collaboration on the Internet

Although collaboration tools have existed for a long time [8], Internet-based multimedia collaboration has recently received a lot of attention mainly due to easy accessibility of the Internet by ordinary users. The Java platform and programming language has also introduced yet another level of easy access: platform-independent computing. As a result, it is very attractive to use Java to design multimedia collaboration systems for the Internet. Today there are many systems, which use Java for multimedia collaboration. However, most of these systems require the shared Java application to be re-written according to the collaboration system's Application Programming Interface (API)—a task which is sometimes difficult or even impossible. In this paper, we describe a practical approach for transparent collaboration with Java. Our approach is transparent in that the Java application can be shared as is with no modifications. The main idea behind our system is that user events occurring through the interactions with the application can be caught, distributed, and reconstructed, hence allowing Java applications to be shared transparently. Our architecture allows us to make the huge installed base of Java applications collaborative, without any modification to their original code. We also prove the feasibility of our architecture by implementation of the JASMINE¹ prototype.     

Collaborative data visualization for Earth Sciences with the OptIPuter

Collaborative visualization of large-scale datasets across geographically distributed sites is becoming increasingly important for Earth Sciences. Not only does it enhance our understanding of the geological systems, but also enables near-real-time scientific data acquisition and exploration across distant locations. While such a collaborative environment is feasible with advanced optical networks and resource sharing in the form of Grid, many technical challenges remain: (1) on-demand discovery, selection and configuration of supporting end and network resources; (2) construction of applications on heterogeneous, distributed environments; and (3) use of novel exotic transport protocols to achieve high performance. To address these issues, we describe the multi-layered OptIPuter middleware technologies, including simple resource abstractions, dynamic network provisioning, and novel data transport services. In this paper, we present an evaluation of the first integrated prototype of the OptIPuter system software recently demonstrated at iGrid 2005, which successfully supports real-time collaborative visualizations of 3D multi-gigabyte earth science datasets.