Arachne: Planning the telephone network at NYNEX

Arachne provides an excellent example of the success that can be derived from an effective integration of expert systems and optimization techniques. Automating IOF planning at NYNEX was an extremely challenging problem involving conflicting constraints: (i) the IOF network planning problem is quite complex, and (ii) the size of NYNEX s IOF network is quite large. In Arachne, we resolve these conflicting constraints by decomposing the planning task in such a way that only two types of subtask remain: (i) subtasks in which the size of the data is large, and the equipment cost of decisions small, an (ii) subtasks in which the data size is small and the equipment cost of decisions high. We apply heuristics to the former types of subtasks and optimization techniques to the latter. Combining heuristics and optimization techniques in this way provides a very good solution that optimizes the IOF network where capital investment is greatest. Copyright     

Migrant threads on process farms: parallel programming with Ariadne

We present a novel and portable threads-based system for concurrent applications on shared- and distributed-memory environments. The Ariadne system provides stateful user-space threads that can be very effective in medium to coarse grained applications. The interface is the same for uniprocessors and multiprocessors. Sequential programs are readily converted into parallel programs for shared or distributed memory, with low development effort. Ariadne supports the development of customized schedulers, and offers a thread migration capability in distributed environments. Scheduling of computations at the threads level enables both task- and data-driven executions. Thread migration is a useful feature which turns remote memory accesses into local accesses, enables load-balancing and simplifies program development. Ariadne employs a unique runtime stack rewriting mechanism to migrate threads between homogeneous processors. Ariadne currently runs on the SPARC (SunOS 4.x, SunOS 5.x), Sequent Symmetry, Intel Paragon, Silicon Graphics IRIX and IBM RS/6000 environments. We present some examples of Ariadne programs, along with performance measurements. © 1998 John Wiley & Sons, Ltd.     

A communication system supporting large datagrams on a local area network

This paper describes an implementation of a software interface designed for use from within UNIX

1 UNIX is a trademark of A T & T Bell Laboratories.

application programs for network communications. This interface provides the abstraction of possibly very large datagrams, supports ‘scatter-gather’ facilities, and maintains standard network addresses consisting of (host number; port number) pairs. This interface has been provided on different data communication facilities, allowing uniform program access to those facilities. The particular implementation developed for a local area network is described, and performance results obtained are examined and compared with those obtained from a conventional datagram interface to that network. The results obtained confirm that the abstraction of very large datagrams enables the construction of an efficient mechanism for process-to-process communications over the network that is not only more convenient, but also has significant performance advantages over the use of conventional (small) datagrams.     

EMPOWER: a cluster architecture supporting network emulation

Network research generally requires a simulation or emulation environment to test protocol implementations, to evaluate the performance of a scheme or a system, and to study complicated and highly varying network operations. For large network simulation, simulators consume a large amount of time and memory; and its result is largely based on some modeling assumptions that may not hold in the real world. Emulators are difficult to scale for large network emulation because of the high cost of equipment if a one-to-one mapping scheme is employed. Otherwise, the target network has to be abstracted to a single router modeled with some performance metrics. We present a distributed IP network emulator cluster EMPOWER, which not only can be used to emulate a large network with a limited number of commodity computers, but also can generate user-defined arbitrary network conditions and traffic dynamics at packet level for specific test scenarios. EMPOWER is highly scalable in that each emulator node could be configured to emulate multiple network nodes, and the increment of the number of emulator nodes does not affect emulation validity. Some significant research issues such as network mapping and mobile wireless network emulation are discussed and addressed. Preliminary emulation results show that EMPOWER is capable of assisting the study of both wireline and wireless network protocols and applications.     

A portable UPnP-based high performance content sharing system for supporting multimedia devices

Since the development of traditional home multimedia is yet to be improved, the various multimedia devices are used for playing media content. Under the advancement of modern science and technology, there are various formats of compact discs to store and play multimedia content, such as VCD, DVD, portable disks, etc., and the latest, Blu-ray disc. However, it is difficult for these devices to share the content without any configuration. In order to solve the problem of playing effectively, we propose a portable UPnP-based high performance content sharing system for supporting multimedia devices, which includes a content sharing server, and media players. The content sharing server can realize the share services and file control of the portable disk, iPod, DVD, digital TV, and other devices, so that users no longer need to carry out complex processes to install software and settings, as the media players can allow users to play the multimedia file on any media device.     

支持视频标签的网络视频监控系统

采用TI公司的TMS320C6713型号DSP开发板和三星公司的2410开发板设计了一个嵌入式网络视频监控系统.实时视频监控数据量多,压缩的计算量较大,采用DSP进行压缩可以发挥其速度快的特点.为了方便视频数据的传输和存储,实现监控系统的网络化,在ARM上移植嵌入式Linux来满足要求.同时该系统在客户端支持对视频数据的检索,用户可以快速找到自己想要观看的视频点,不必去浏览整个视频文件.     

Perseus: Retrospective on a portable operating system

We describe the operating system Perseus, developed as part of a study into the issues of computer communications and their impact on operating system and programming language design. Perseus was designed to be portable by virtue of its kernel-based structure and its implementation in Pascal. In particular, machine-dependent code is limited to the kernel and most operating systems functions are provided by server processes, running in user mode. Perseus was designed to evolve into a distributed operating system by virtue of its interprocess communication facilities, based on message-passing. This paper presents an overview of the system and gives an assessment of how far it satisfied its original goals. Specifically, we evaluate its interprocess communication facilities and kernel-based structure, and discuss its portability. We close with a brief history of the project, pointing out major milestones and stumbling blocks.     

State restoration in Ada 95: a portable approach to supporting software fault tolerance

Studies indicate that techniques for tolerating hardware faults are so effective that software design errors are the leading cause of all faults encountered. To handle these unanticipated software faults, two main approaches have been proposed: N-version programming and recovery blocks. Both are based on the concept of design diversity: the assumption that different designs will exhibit different faults (if any) for the same inputs and will, therefore, provide alternatives for each other. Both approaches have advantages, but this paper focuses upon recovery blocks; specifically, the requirement to save and restore application state. Judicious saving of state has been described as “checkpointing” for over a decade. Using the object-oriented features of the revised Ada language (Ada 95) – a language widely used in this domain – we present three portable implementations of a checkpointing facility and discuss the trade-offs offered by each. Results of the implementation of these mechanisms are used to highlight both the strengths and weaknesses of some of the object-oriented features of Ada. We then show a reusable implementation of recovery blocks illustrating the checkpointing schemes. A performance analysis is made and measurements are presented in support of the analysis.     

Decision supporting functionality in a virtual enterprise network

Enterprises are now facing growing global competition and the continual success in the marketplace depends very much on how efficient and effective the companies are able to respond to customer demands. The Internet has provided a powerful tool to link up manufacturers, suppliers and consumers to facilitate the bi-directional interchange of useful information. The formation of virtual enterprise network is gathering momentum to meet this challenge. The idea of virtual enterprise network is meant to establish a dynamic organization by the synergetic combination of dissimilar companies with different core competencies, thereby forming a “best of everything” consortium to perform a given business project to achieve maximum degree of customer satisfaction. In this emerging business model of virtual enterprise network, the decision support functionality, which addresses the issues such as selection of business partners, coordination in the distribution of production processes and the prediction of production problems, is an important domain to be studied. This paper attempts to introduce a Neural On-Line Analytical Processing System (NOLAPS), which is able to contribute to the creation of decision support functionality in a virtual enterprise network. NOLAPS is equipped with two main technologies for achieving various objectives, including neural network for extrapolating probable outcomes based on available pattern of events and data mining for converting complex data into useful corporate information. A case example is also covered to validate the feasibility of the adoption of NOLAPS in real industrial situations.     

MUSS—a portable operating system

This paper describes a technique for producing a machine-independent operating system with a high level of performance. The technique is based on the definition of a hypothetical ideal machine, which acts as the target computer for the operating system. The characteristics of this ideal machine are described in detail.     

TNet: a reliable system area network

A major departure from traditional I/O systems, TNet is a new system area network designed to support current and future needs for reliable, efficient communications among processors and peripherals. It is an extensible hardware-software layer that allows very large configurations by logically and physically isolating processor buses from I/O buses. TNet features wormhole routing, packet-switched transfers, and point-to-point links     

Customized purchase supporting expert system: UNIK-SES

An expert system that assists the customized men's wear purchasing process is developed. In the past, configuration systems have adopted either a rule- or a constraint-based representation. To overcome the limitation of the representation, an integrated representation of the Constraint and Rule Satisfaction Problems (CRSP) is adopted. Since the general purpose tool UNIK-CRSP provides concurrent, integrated and interactive reasoning, UNIK-CRSP is very suitable for assisting the personalized customer product configuration process in a natural manner. Using UNIK-CRSP, the domain-specific tool UNIK-SES is developed with the additional features of candidate products selection and user interfaces. This approach should be useful for customer support in electronic marketing on the information superhighway.     

An object-based middleware supporting efficient interoperability on a smart home network

This paper proposes a novel object-based home network middleware for supporting the interoperability among home devices and smart grid devices. This middleware provides various types of abstract objects for flexible representation of heterogeneous home devices, which are classified based on their characteristics. It is also flexible enough to allow addition of new protocols and message conversion between different protocols through an abstraction layer, which are not supported by existing home network middlewares so that various protocols can be supported. As a result, it can be utilized to provide the interoperability among a variety of devices from sensors to typical home appliances as well as smart grid devices such as a home electric generator and a battery, which adopt different protocols. In order to demonstrate that home devices and smart grid devices are interoperable through the proposed middleware, we implement applications based on the middleware on a target platform consisting of embedded boards, sensors and laptops for emulation purposes of a home network. According to our emulation, this middleware can provide efficient interoperability among home devices and smart grid devices for future energy efficient home.     

TRIPOS—a portable operating system for mini-computers

There are several successful operating systems for mini-computers written in high level languages and the time is now ripe for the development of portable systems for such machines. The system described in this paper is primarily designed to provide a friendly interactive multiprocessing environment for a single user. From his point of view, substantial parts of the system are completely machine independent. These include, for instance, the filing system, the command language, text editors, overlaying facilities and interprocess communication primitives. The system is suitable for many different application areas ranging over process control, data acquisition, data communication, text handling, data base systems and teaching.     

可移植的嵌入式WEB服务器软件设计

本文结合嵌入式系统的具体特点．着重探讨了软件在不同系统之间的可移植性问题,并在此基础上提供了一种可移植嵌入式WEB服务器软件的设计方法。     

OmniStore: Automating data management in a personal system comprising several portable devices

The ever growing amount of data generated and consumed on the move using portable devices gives rise to serious data management issues. The fact that each person may own and is likely to carry several such devices further aggravates this problem. On the other hand, new opportunities for achieving cleverer device interaction emerge due to the increased wireless networking capabilities of wearable and portable devices. This paper introduces OmniStore, a system that combines portable devices and infrastructure-based services to relieve the user from explicit and time consuming file management tasks. Our approach is to let devices communicate with each other as well as with a repository service, in an opportunistic and asynchronous fashion, to perform a variety of file movement and copying actions behind the scenes, which would have typically required considerable explicit user interaction.     

Survivable network system analysis: a case study

The Survivable Network Analysis method permits assessment of survivability at the architecture level. Steps include system mission and architecture definition, essential capability definition, compromisable capability definition, and survivability analysis of architectural soft-spots that are both essential and compromisable. The article summarizes application of the method to a subsystem of a large-scale, distributed health care system     

Clinical acceptance of a low-cost portable system for postural assessment

The drive towards evidence-based practice in health-care requires changes in work practices and supporting technology. In response to the requirement to provide evidence, the current research proposes a new low-cost system for 3-D postural assessment. The aims of the study were (1) to assess the technology acceptance model (Davis 1993) for the new system and (2) to derive user requirements with user involvement early in the development process. A prototype system was developed and demonstrated to physiotherapists. Technology acceptance was assessed using standardized questions (Davis and Venkatesh 1996) and user needs were assessed with open-ended questions. Relations between the technology acceptance components confirmed findings of previous research, with perceived ease of use and perceived usefulness identified as pivotal factors in clinical acceptance, and implications for design were drawn. Specific user requirements for system development were derived from the qualitative results. The prospects for computer-aided quantitative assessment of posture are discussed.     

Modelling,dynamics and control of a portable DMFC system

A dynamic model for a direct methanol fuel cell and its ancillary units is presented, in which all ancillary units perform only one operation each. The system’s losses and main dynamics (cathodic oxygen fraction, anodic methanol concentration, stack temperature, system water holdup) are analysed for stability and time constants. The system is found to be stable in all of its dynamics except for that of water holdup. The influence of external conditions, such as temperature and humidity, on system feasibility is analysed; the capability of system autonomous operation depends essentially on environmental conditions and on the chosen air excess ratio. Decoupled single-input, single-output controllers, some of which employing feedback, are applied to maintain the system at a certain set point. System simulations are performed, confirming the performance of the proposed controllers, their ability to stabilise the water holdup, and the absence of interaction-induced oscillations; the system can be started up in about ten minutes with the presented parameters.