Supporting real-time and multimedia applications on the Mercuritestbed

This paper describes the distributed system, network and software architecture, the application development environment, the performance, and the early lessons learned on the ATM LAN testbed Mercuri established at the Honeywell Technology Center, to develop distributed multimedia technologies for real-time control applications. We have developed a client-server-based software architecture on Sun Sparcstation-2s connected by a Fore Systems' ASX-100 ATM switch, with video processing handled by Parallax's X Video cards. The architecture enables network-transparent applications and provides simple primitives for multimedia capture, display, transmission, storage, and retrieval. A real-time multimedia-in-the-loop control application was developed as the vehicle for testing the capabilities and performance of the network. Our test measurements focus on the end-user-level performance metrics such as message throughput and round-trip delay as well as video-frame jitter under no-load and load conditions. Our results show that the maximum burst throughput that can be supported at the user level is 48 Mb/s using AAL 5, while round-trip delays for 4-kbyte messages are about 3 ms. Our experience reveals a number of performance bottlenecks and open issues in using commercial ATM switches for practical applications. Our conclusions are outlined     

Database interoperation support in multimedia applications:architecture and methodology

One of the major concerns for the early adopters of the new media technologies is how to safeguard their investments in the face of rapid technological change. In this paper, we argue that technological change and the ensuing problems are a well-known issue in databases, and that the multimedia industry can benefit from lessons learned in database technology. Moreover, we argue that meta-translation, a specific approach to software interoperation that has been developed in the context of heterogeneous databases, may also be useful in multimedia applications, particularly in converting proprietary annotation and indexing schemes into emerging or existing standards, such as MPEG-7. This technology automates the construction of conversion tools significantly, thus reducing the cost of migration and interoperation. Beginning with a discussion of architectural aspects of multimedia systems and a summary of relevant interoperation standards, the paper proceeds to describe and then to assess meta-translation as an approach and technology in this context     

Establishing academic programs in integrated media systems

For four years, we have been developing a wide range of graduate and undergraduate degree programs related to integrated media systems on behalf of the Integrated Media Systems Center (IMSC), for the School of Engineering at the University of Southern California (USC). The IMSC is a National Science Foundation Engineering Research Center (ERC) that became operational in 1996. It is not an academic department; however, one of its important missions is education. Most of the developed degree programs have been for engineering students, but one is available to all students. These degree programs are administered either by an academic department (e.g., computer science) or by an assistant dean of the School of Engineering. The purpose of this article is to not only describe these degree programs, but to also provide some lessons that have been learned along the way, lessons that may help expedite the development of similar programs at other universities     

Reliable prediction of EM radiation from a PCB at the design stageof electronic equipment

This paper presents a composite computer-aided design (CCAD) package for prediction of electromagnetic (EM) radiation from a printed circuit board (PCB) at the design stage of equipment. Such a CCAD package has been developed by combining an EM computation tool such as numerical electromagnetic code (NEC)-2, with other circuit design packages (CDPs). The method of prediction of EM radiation using the CCAD is well described in this paper. The predicted EM radiation has been validated experimentally and results showing good agreement are presented. Finally, the reliability of the CCAD package is investigated and presented     

FUTURE MULTIMEDIA COMMUNICATIONS VIA SATELLITE

We are now moving into an era when conventional speech service will expand to full multimedia service offerings. This paper looks at ways in which satellite systems could provide such services in both the mobile as well as the fixed bands and the integration and inter-operability of such systems. Provision of multimedia services by ATM to integrate with an ATM core network is taken as the basis of the future network. Some of the constraints and difficulties of provision of ATM over satellite are discussed as well as some potential solutions for the ATM wireless protocols and network architectures which potentially could provide such services. Finally, some suggestions of how new orbit constellations could help meet these requirements are given. © 1996 by John Wiley & Sons, Ltd.     

Achieving multimedia communications on a heterogeneous network

A heterogeneous intelligent network has been designed and implemented to allow multimedia real-time communications and messaging among local area network workstations with logically associated speakerphones and among ISDN voice/data terminals with transparent tablets on top of bitmap screens and stylus pens. The architecture, presentation, editing, storage, and retrieval of multimedia documents in these two different kinds of terminals are described. The messages and protocol conversion facilities used for multimedia communications are presented, as are the lessons learned in internetworking a local area network with ISDN     

Building open programmable multimedia networks

Recent advances in distributed systems and transportable software and increasing demand for better quality of service (QoS) control in multiservice networks are driving a reexamination of network software architectures. We established the Comet (Control, Management, and Telemedia) Group at Columbia University's Center for Telecommunications Research to provide comprehensive understanding of network software architecture for the 1990s and beyond. This research focuses on developing new network architectures that support service creation, QoS control, and the joint allocation of computing and communications resources. This provides an opportunity to reconcile the perspectives of the computing and communication communities. Future multiservice (multimedia) networks will carry traffic such as video, audio, and computer data with diverse QoS requirements. Such networks will thus require that we develop ways to manage many physical and logical entities, services, and users     

Propagation of electromagnetic waves at MHz frequencies through seawater

The nature of the ocean environment and its vast size has necessitated the development of sophisticated equipment and techniques for various underwater applications including diver-to-diver communications, ROV/AUV docking, communications and oil and gas explorations. To facilitate scientific exploration a wide variety of systems and vehicles have been developed to operate within the shallow continental shelf region or in deep oceans. For successful underwater electromagnetic (EM) wave operation, knowledge is required of the wave transmission properties of seawater over all distances both short and long. This information is required for such activities such as: sensor systems, imaging, position fixing, measurement of speed, obstacle detection and avoidance, guidance, communication of data/voice and remote control. This paper presents a new approach of EM wave propagation through seawater. The experimental results conducted in the laboratory and the real environment of seawater is presented.     

Managing IP services over a PACS Packet Network

We have developed a system and network architecture to provide IP services in the Personal Access Communications System (PACS). IP datagrams are delivered to PACS users through the PACS packet-mode data service, achieving more efficient usage of wireless resources and supporting multimedia applications such as MBone audio and video. The architecture presented in this article augments the PACS voice network with IP routers and backbone links, called the PACS Packet Network (PPN), and is connected to the global Internet via gateways. Compared to the cellular digital packet data (CDPD) network, which employs its own network-layer mobility protocol and thus supports roaming within the CDPD network only, we have incorporated Mobile IP into the PACS handoff mechanism to further achieve global IP mobility. We have also developed native PACS multicast and a group management scheme to efficiently handle dynamic IP multicast and MBone connectivity. These features seamlessly integrate PACS into the global Internet and provide standard-conforming IP services with global mobility     

Computer Simulation of Axis-Encircling Beams Generated by an Electron Gun with a Permanent Magnet System

Results from computer aided design of a novel electron gun generating axis-encircling beams are presented and discussed. Numerical experiments were performed by the new version of the software package GUN-MIG named GUN-MIG/CUSP. It is based on a self-consistent relativistic model and is developed as a problem oriented tool for analysis of electron-optical systems with magnetron injection guns (MIG) and electron guns with field reversal (cusp guns), forming axis-encircling beams. As a result of the simulations an electron-optical design of a novel electron gun with permanent magnet system was accomplished. The gun is expected to form high quality beams with small velocity spread and beam ripple. Parameters of the generated beams are appropriate for a prospective weakly relativistic high harmonic large orbit gyrotron (LOG). The development of such device is in progress now at the Research Center for Development of Far-Infrared Region (FIR Center) at Fukui University.     

A Numerical Methodology for the Prediction of the Near-Field Parasitic Electromagnetic Emissions of Solar Panels

This paper presents a methodology that is developed to assess the parasitic electromagnetic (EM) emissions of a satellite solar panel from a quasi-static to several tens of megahertz bandwidth. In the method, the solar panel is first modeled as an equivalent electric circuit, which allows the computation of the current distribution in all the elements using Spice-like software. The model is then converted into a network of electric dipoles, which permits to calculate the total EM emissions of the solar panel at a given point by the vectorial summation of the EM emissions due to each electric dipole. Thus, only the dipolar moment and the position and the orientation of each electric dipole are required. Encouraging experimental validations performed on a prototype solar panel are presented to illustrate the efficiency and the accuracy of the method. The method described in this paper is considered as a first step required in order to prepare wider applications on real satellites in the near future.      

An architecture for real-time multimedia communication systems

A multimedia communication system includes both the communication protocols used to transport the real-time data and the distributed computing system (DCS) within which any applications using the protocols must execute. The architecture presented attempts to integrate these communications protocols with the DCS in a smooth fashion in order to ease the writing of multimedia applications. Two issues are identified as being essential to the success of this integration: the synchronization of related real-time data streams, and the management of heterogeneous multimedia hardware. The synchronization problem is tackled by defining explicit synchronization properties at the presentation level and by providing control and synchronization operations within the DCS which operate in terms of these properties. The heterogeneity problems are addressed by separating the data transport semantics (protocols themselves) from the control semantics (protocol interfaces)     

Multimedia dictionary network application: design andimplementation

Proficiency in foreign languages is essential for professionals from countries in transition. A multimedia dictionary Internet application may offer needed help in everyday activities as well as in distance-learning systems. A multimedia dictionary is considered as both a conventional dictionary tool and a distance-learning network application. We analyze the architecture and implementation issues arising in the design and implementation of a multimedia dictionary network application. The application is considered multimedia since it is designed to support textual, visual, and audio information content. Practical implementation is shown to be feasible with current technology, but a lack of available multimedia standards has been recognized. This is why we have considered the existing standards as well as the standards in development. The application is developed in Java language, and may be run as either a standalone application or an applet. The latter entails accessibility in a ubiquitous manner to a large number of users. The application is intended for both non-native English users and professionals exposed to specific technical terminology     

电磁兼容设计如何融入电子产品的设计流程

针对电子产品生产企业面临的困境,详细地论述了电磁兼容设计的开发流程,提出每一阶段的工作内容以及如何保证PCB设计符合EMC设计规范的方法,由此可以帮助企业将电磁兼容设计更好地融入到产品的开发设计流程中.     

基于红外信标网络的无线智能导游系统的设计

提出了一种新颖的红外无线智能导游系统的设计方案。基于当前先进的信标网络技术及手持移动计算技术,采用信标网络中的不同节点的红外信标信号自动选通游客手中的便携式信息终端设备,使之成为视听一体化移动的可随机点播的多媒体平台,同步提供可选的多语种语音讲解、视频播放及帮助信息功能,实现一种便携的无线智能嵌入式多媒体导游系统。介绍了总体的设计思想及系统的软硬件构成。上海科技馆、江苏周庄等地的应用实践表明,该装置稳定可靠,使用效果和社会反响良好.     

Software management—A survey of the practice in 1980

The primary thrust of this paper is to explore many of the problems currently plaguing software development activities and to propose how some of the recently developed management practices may be employed in dealing with them. The practices described range from people organizations (e.g., chief programmer teams) to fully automated engineering tools (e.g., software requirements engineering methodology). A number of techniques are presented. These include methods for coping with communications problems in the requirements definition activity, for evolving a facility which will help increase the productivity of software designers and proggammers, and for maintaining a high degree of visibility during the elusive unit design code and test phase of a project. A very practical view of the management problems and suggested approaches is presented. Key principles, potentials "pitfalls," and unresolved concerns are addressed from a viewpoint of where the state of the art is today and where the industry appears to be heading in the mid-1980's.     

Fast and Automated Electromigration Analysis for CMOS RF PA Design

This paper presents fast and automated electromigration (EM) reliability modeling by using automated modeling generation (AMG) algorithm. The AMG converts human based EM modeling into an automated modeling and simulation process with the help of ANSYS parametric design language (APDL) program. For automating the neural model training process, training-driven adaptive sampling is applied to integrate data generation, data distributions determination, model structure adaptation, training and testing into a unified framework. Fully automated reliability model construction and simulation is achieved for the first time. This method effectively shortens the period of EM modeling by using dynamic sampling method. Furthermore, the heat generation from active devices has been considered to describe the heat effect on the interconnect reliability. Through the proposed technique, the allowable sizes, temperature and output power of a CMOS radio frequency power amplifier (RF PA) are derived to give reliability criteria for PA designer.     

Enhancing call-detail reporting using multimedia technologies

Two features have motivated the Web's growth: timely information; and information not previously available everywhere. The most common complaint about older application systems is their isolation, they are not easily accessible to others. This calls for integrating the Web, a distribution mechanism, with the application system, providing timely information. The maintenance costs of both hardware and software are comparable with the older systems. Superior information technology solutions can help us obtain such desirable results. One such solution is a call-detail application, not previously available to users through the Web having multimedia capabilities. The Advanced Telecommunications Institute (ATI) designed and implemented the call-detail reporting application, which can be directly accessed at the end-user's desktop using a Web browser. We discuss the project-enhancing call-detail reporting using multimedia technologies     

MPEG Reconfigurable Video Coding: From specification to a reconfigurable implementation

This paper demonstrates that it is possible to produce automatic, reconfigurable, and portable implementations of multimedia decoders onto platforms with the help of the MPEG Reconfigurable Video Coding (RVC) standard. MPEG RVC is a new formalism standardized by the MPEG consortium used to specify multimedia decoders. It produces visual representations of decoder reference software, with the help of graphs that connect several coding tools from MPEG standards. The approach developed in this paper draws on Dataflow Process Networks to produce a Minimal and Canonical Representation (MCR) of MPEG RVC specifications. The MCR makes it possible to form automatic and reconfigurable implementations of decoders which can match any actual platforms. The contribution is demonstrated on one case study where a generic decoder needs to process a multimedia content with the help of the RVC specification of the decoder required to process it. The overall approach is tested on two decoders from MPEG, namely MPEG-4 part 2 Simple Profile and MPEG-4 part 10 Constrained Baseline Profile. The results validate the following benefits on the MCR of decoders: compact representation, low overhead induced by its compilation, reconfiguration and multi-core abilities.     

扫描电镜中的算法进展

在过去的二十年中,同透射电镜一样,在扫描电镜上也取得了许多硬件的进展,如浸没式物镜、减速模式和新型探测器技术.测试技术的进步包括硬件和软件两方面内涵.伴随硬件的进步,借助信息科学(包括人工智能(AI)和其他统计数学方法),人们在成像和光谱学方面也有了新的机遇.硬件与软件结合,可以实现更高精度、更高通量的表征,也使得如今...