Showing papers on "Testbed published in 1996"

The Parctab Ubiquitous Computing Experiment

Abstract: The ParcTab system integrates a palm-sized mobile computer into an office network This project serves as a preliminary testbed for Ubiquitous Computing, a philosophy originating at Xerox PARC that aims to enrich our computing environment by emphasizing context sensitivity, casual interaction and the spatial arrangement of computers This paper describes the Ubiquitous Computing philosophy, the ParcTab system, user-interface issues for small devices, and our experience developing and testing a variety of mobile applications

A wideband all-optical WDM network

Abstract: We describe some of the results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks in developing architectures, technology components, and applications for the realization of scaleable, wideband, and transparent optical wavelength-division multiplexing (WDM) networks. Our architecture addresses all-optical transport over the wide, metropolitan, and local areas. It utilizes wavelength partitioning, routing, and active multiwavelength cross-connect switches to achieve a network that is scaleable in the number of users, data rates, and geographic span. The network supports two services which can be point-to-multipoint or multipoint-to-multipoint simplex or duplex connections. The A service is a transparent physically circuit-switched service and the B-service is a scheduled time-slotted circuit which is transparent within its time slots. We have developed a 20-channel local and metropolitan area WDM testbed deployed in the Boston area, now undergoing characterization and experimental applications.

Multiwavelength reconfigurable WDM/ATM/SONET network testbed

Abstract: This paper describes the multiwavelength reconfigurable all-optical network testbed designed and constructed as a part of the optical networks technology consortium (ONTC) phase I program with a group of working members consisting of Bellcore, Columbia University, Hughes Research Laboratories, Northern Telecom, Rockwell Science Center, Case Western Reserve University, United Technology Research Center, Uniphase Telecommunications Product, and Lawrence Livermore National Laboratories. The architecture of the testbed and its nodes is presented together with a description of the key component technologies. Network control and management is discussed along with applications and services.

Real-time geographic visualization of World Wide Web traffic

Abstract: The rapid growth of the World Wide Web (WWW) is well documented, with WWW sites now advertised in magazines, newspapers, and television commercials. Given current use of the WWW for scientific and educational information sharing and its emerging use for electronic commerce, studying access patterns is an important first step in understanding network implications and in designing future generations of WWW servers that can accommodate new media types and interaction modes. Due in large part to early development of the Mosaic WWW browser by the National Center for Supercomputing Applications (NCSA), the access load on the NCSA WWW server remains extremely high. Using the NCSA WWW server as a high load testbed, we describe Avatar , a virtual reality system for real-time analysis and mapping of WWW server accesses to their point of geographic origin on various projections of the Earth. As HTTP protocols expand to demographic data, the Avatar architecture can be extended to correlate this data as well.

The Rainbow-II gigabit optical network

Abstract: This paper describes the Rainbow-II optical metropolitan area network (MAN), which supports 32 nodes each at 1 Gbit/s over a distance of 10-20 km. Rainbow-II uses optical wavelength-division multiplexing (WDM), in a broadcast star architecture. Each node uses a separate fixed wavelength for transmitting data and a tunable receiver for receiving one of several data streams. The network is implemented in the form of optical network nodes, each attached to a host computer via the high-performance parallel interface (HIPPI). Each network node contains protocol processing hardware to offload the protocol processing work from the host computer onto the node. The goal is to provide full gigabit-per-second bandwidth to end-user supercomputer applications. Preliminary protocol performance measurements in a testbed network are given.

Coherent DS-CDMA: promising multiple access for wireless multimedia mobile communications

Abstract: This paper describes a design concept and the features of coherent DS-CDMA access which supports multimedia services and also flexible system deployment. The testbed implemented for a series of field experiments near Tokyo and some measurement results are reported. In the proposed system, two-layer code assignment and transmit power control based on signal-to-interference (SIR) measurements are used. Pilot symbol-assisted coherent RAKE reception in the reverse link is employed to enhance the transmission quality. This paper also reports on the cell search algorithm used to accomplish rapid cell search under asynchronous cell site operation and low power consuming matched filter implementation. Finally, as an evolutionary step in future technology, an application of an interference canceling scheme and an adaptive beamforming scheme are presented in order to further increase the link capacity.

Real-Time Geographic Visualization of World Wide Web Traffic.

Abstract: The rapid growth of the World Wide Web (WWW) is well documented, with WWW sites now advertised in magazines, newspapers, and television commercials Given current use of the WWW for scientific and educational information sharing and its emerging use for electronic commerce, studying access patterns is an important first step in understanding network implications and in designing future generations of WWW servers that can accommodate new media types and interaction modes Due in large part to early development of the Mosaic WWW browser by the National Center for Supercomputing Applications (NCSA), the access load on the NCSA WWW server remains extremely high Using the NCSA WWW server as a high load testbed, we describe Avatar , a virtual reality system for real-time analysis and mapping of WWW server accesses to their point of geographic origin on various projections of the Earth As HTTP protocols expand to demographic data, the Avatar architecture can be extended to correlate this data as well

Scalability issues for high performance digital libraries on the World Wide Web

Abstract: We investigate scalability issues involved in developing high performance digital library systems. Our observations and solutions are based on our experience with the Alexandria Digital Library (ADL) testbed under development at UCSB. The current ADL system provides online browsing and processing of digitized maps and other geospatially mapped data via the World Wide Web (WWW). A primary activity of the ADL system involves computation and disk I/O for accessing compressed multi resolution images with hierarchical data structures, as well as other duties such as supporting database queries and on the fly HTML page generation. Providing multi resolution image browsing services can reduce network traffic but impose some additional cost at the server. We discuss the necessity of having a multiprocessor DL server to match potentially huge demands in simultaneous access requests from the Internet. We have developed a distributed scheduling system for processing DL requests, which actively monitors the usages of CPU, I/O channels and the interconnection network to effectively distribute work across processing units to exploit task and I/O parallelism. We present an experimental study on the performance of our scheme in addressing the scalability issues arising in ADL wavelet processing and file retrieval. Our results indicate that the system delivers good performance on these types of tasks.

Development of columbia's video on demand testbed

Abstract: This paper describes our progress in developing an advanced video-on-demand (VOD) testbed, which will accommodate various multimedia research and applications such as Electronic News on Demand, Columbia's Video Course Network, and Digital Libraries. Two different prototypes have been completed. The first generation of the testbed was based on a constant-bit-rate (CBR) video server utilizing Ethernet delivery. Contents were encoded and stored as MPEG-2 audio/video elementary streams. Software encoders/decoders were used in content generation and playback. The second generation of the testbed was enhanced with the capability of transmitting true MPEG-2 transport streams over the campus ATM network as well as the wide-area NYNET ATM network. A real-time video pump and a distributed application control protocol (MPEG-2's DSM-CC) have been incorporated. Hardware decoders and set-tops are being incorporated to test wide-area video interoperability. Our VOD testbed also provides an advanced platform for implementing proof-of-concept prototypes of related research. Our current research focus covers video transmission with heterogeneous quality-of-service (QoS) provision, video storage architecture design, content-based video indexing and browsing, multi-resolution (MR) video coding, efficient manipulation of compressed video, and advanced user interfaces. An important aim is to enhance interoperability. Accommodation of practical multimedia applications and interoperability testing with external VOD systems are currently being undertaken.

OTTER: The design and development of an intelligent underwater robot

Abstract: Recent advances in sensing and intelligent control technologies open a whole new dimension in underwater autonomy. However, before truly-capable, autonomous underwater robots can be created for subsea intervention and exploration, many research issues must be first investigated and developed experimentally on testbed platforms.

A low power architecture for wireless multimedia systems: lessons learned from building a power hog

Abstract: UCLA has constructed a network testbed which serves as an environment for developing wireless multimedia systems. The first generation testbed consists of a set of battery powered terminals with low-bit rate video codecs connected to a peer-to-peer multi-hop network over spread spectrum radios. Not surprisingly, this set of features draws considerable current during operation, and achieves a battery life of approximately one hour using a 24 Wh NiMH battery. This report discusses the power consumption of the existing testbed, lessons learned during its development, and a course of action directed to improving battery life for a portable multimedia terminal. The key advancement is the development of a complete system architecture focused on turning off power to components and subsystems. Starting with communications protocols, and progressing up through processors to APIs, this new design extends useful battery life through a significant reduction in current drain.

Application of intelligent monitoring for super long distance teleoperation

Abstract: Time delay and limited communication capacity are the primary constraints in super-long distance telerobotic systems such as space telerobotic systems. Intelligent monitoring is efficient for this problem to provide a function which selects important scenes to help the operator through a monitoring camera. We constructed a telerobotic testbed which includes a connection through the international ISDN and typical space structure (space robot, truss structure land ORU). We conducted trans-Pacific teleoperation experiments using the testbed in ETL as the remote site and a telerobotic console at JPL (Jet Propulsion Laboratory in Pasadena, California) as a local site. Experimental results showed intelligent monitoring to be effective for the above problems.

Integrated modeling methodology validation using the micro-precision interferometer testbed

Abstract: This paper validates the integrated modeling methodology used for design and performance evaluation of complex opto-mechanical systems, particularly space-borne interferometers. The methodology integrates structural modeling, optical modeling, and control system design into a common environment, the Integrated Modeling of Optical Systems (IMOS) software package. The validation utilized the /spl mu/icro-precision interferometer (MPI) testbed, a ground-based full-scale hardware model of a spaceborne interferometer. This paper presents a comparison of integrated model predictions with MPI laboratory measurements, indicating that the integrated modeling methodology has the accuracy required to evaluate interferometry mission designs with confidence.

A global spacecraft control network for spacecraft autonomy research

Abstract: The development and implementation of the Automated Space System Experimental Testbed (ASSET) space operations and control network, is reported on. This network will serve as a command and control architecture for spacecraft operations and will offer a real testbed for the application and validation of advanced autonomous spacecraft operations strategies. The proposed network will initially consist of globally distributed amateur radio ground stations at locations throughout North America and Europe. These stations will be linked via Internet to various control centers. The Stanford (CA) control center will be capable of human and computer based decision making for the coordination of user experiments, resource scheduling and fault management. The project's system architecture is described together with its proposed use as a command and control system, its value as a testbed for spacecraft autonomy research, and its current implementation.

Performance analysis in high-speed wide area IP-over-ATM network: top-to-bottom end-to-end monitoring

Abstract: We describe an approach to the analysis of the performance of distributed applications in high-speed wide area networks. The approach is designed to identify all of the issues that impact performance, and isolate the causes due to the related hardware and software components. We also describe the use of a distributed parallel data server as a network load generator that can be used in conjunction with this approach to probe various aspects of high-speed distributed systems from top to bottom of the protocol stack and from end to end in the network. To demonstrate the utility of this approach we present the analysis of a TCP-over-ATM problem that was uncovered while developing this methodology. This work was done in conjunction with the ARPA-funded MAGIC gigabit testbed.

Mobile Network Tracing

Abstract: Mobile networks are both poorly understood and difficult to experiment with. This RFC argues that mobile network tracing provides both tools to improve our understanding of wireless channels, as well as to build realistic, repeatable testbeds for mobile software and systems. The RFC is a status report on our work tracing mobile networks. Our goal is to begin discussion on a standard format for mobile network tracing as well as a testbed for mobile systems research. We present our format for collecting mobile network traces, and tools to produce from such traces analytical models of mobile network behavior.

A novel teleoperated long-reach manipulator testbed and its remote capabilities via the Internet

Abstract: During the 1995 DOE Robotics Forum at Albuquerque, New Mexico, Georgia Tech's Intelligent Machine Dynamics Laboratory demonstrated remote display capabilities of its telemanipulated long-reach manipulator testbed through the Internet. This paper describes the testbed and addresses the methods, limitations, and capabilities of remote operations.

NPS Phoenix AUV software integration and in-water testing

Abstract: The NPS Phoenix autonomous underwater vehicle (AUV) is a student research testbed for shallow-water minefield mapping missions. We discuss implementation of the execution, tactical and strategic levels of the rational behavior model robot architecture. Simulation-based design using an underwater virtual world has been a crucial advantage permitting rapid development of disparate software and hardware modules. Details are provided on process coordination, navigation, real-time sonar classification, path replanning around detected obstacles, networking, sonar and hydrodynamics modeling, and distributable computer graphics rendering. In-water experimental results are presented and evaluated.

ATM and satellite distribution of multimedia educational courseware

Abstract: The Distributed and Interactive Courseware Environment (DICE) is a system for large-scale delivery of multimedia hypertext-based courseware to school sites without high-speed network connectivity using satellite technologies. DICE is being developed on a testbed consisting of (1) a network-resident architecture supported by a high-speed ATM WAN backbone, (2) a classroom-resident architecture consisting of PC LANs in participating school classrooms, and (3) a satellite communications infrastructure serving as a communications link between the network- and classroom-resident architectures. Based on real-time classroom performance evaluation, the network-resident architecture incrementally and adaptively delivers courseware segments to the receiving classroom-resident architecture via satellite.

Virtual Reality Over High-Speed Networks

Abstract: The Supercomputing 95/GII Testbed supported VR-to-VR and supercomputing-to-VR communications that enabled researchers to investigate complex problems over distance.

A lightweight media access protocol for a WDM-based distributed shared memory system

Abstract: This paper presents a media access protocol designed for LIGHTING, a WDM testbed currently under construction which has been designed for high-performance supercomputer interconnection. The architecture is based on a dynamically reconfigurable hierarchical WDM network that is being constructed to interconnect a large number of supercomputers and create a distributed shared memory (DSM) environment. This paper describes the network media access protocol based on a single tunable transmitter and single tunable receiver (TT-TR) per node. The protocol exploits the bimodal traffic characteristics of a DSM system. The primary objectives of the protocol design are reduced average latency per packet, support of broadcast/multicast, and support of collisionless communication. The proposed approach is compared to an earlier protocol based on one tunable transmitter and one fixed receiver (TT-FR) per node. The performance of the protocol in terms of average latency and channel utilization is analyzed for varying system characteristics such as number of nodes and channels.

A testbed for parallel simulation performance prediction

Abstract: The overwhelming complexity of influencing factors determining the performance of parallel simulation executions demands a performance oriented development of logical process simulators. This paper presents an incremental code development process that supports early performance predictions of Time Warp protocols and several of its optimizations. A set of tools, N-MAP, for performance prediction and visualization has been developed, representing a testbed for a detailed sensitivity analysis of the various Time Warp execution parameters. As an example, the effects of various performance factors like the event structure underlying the simulation task, the average LVT progression per simulation step, the commitment rate, state saving overhead, etc. are demonstrated. We show how the scenario management features provided by the N-MAP tool can be efficiently utilized to predict performance sensitivities. For the particular example, the Time Warp protocol, though highly involved, N-MAP was able to predict the per formance sensitivity that was measured from the full implementation executing on the Meiko CS-2.

The MAGlC project: from vision to reality

Abstract: In the MAGIC project, three major components-an ATM internetwork, a distributed, network-based storage system; and a terrain visualization application-were designed, implemented, and integrated to create a testbed for demonstrating real-time, interactive exchange of data at high speeds distributed resources. The MAGIC internetwork, depicted includes six high-speed local area networks (LANs) interconnected by a wide area network (WAN) backbone. The testbed was developed as a system, with special consideration to how performance was affected by interactions among the components. This article presents an overview of the project, with emphasis on the challenges associated with implementing complex distributed system, and with coordinating a multi-organization collaborative project that relied on distributed development. System level design issues and performance measurements are described, as it is a tool that was developed for analyzing performance and diagnosing problems in a distributed system. The management challenges that were encountered and some of the lessons learned during the course of the three-year project are discussed, and a brief summary of MAGIC-II, a follow-on project, is given.

External servicing testbed for automation and robotics

Abstract: The External Servicing Testbed for Automation and Robotics (ESTAR) was developed on behalf of the European Space Agency (ESA) as an open system suitable for easy implementation of new control concepts, algorithms and operational procedures, and integration of new components and subsystems. In this article, the authors present experimental results relevant to the execution of a reference task for space robotics, namely the replacement of an orbital replacement unit (ORU).

Cooperative material handling by human and robotic agents: Module development and system synthesis

Abstract: In this paper we present a collaborative effort to design and implement a cooperative material handling system by a small team of human and robotic agents in an unstructured indoor environment. Our approach makes fundamental use of the human agent's expertise for aspects of task planning, task monitoring and error recovery. Our system is neither fully autonomous nor fully teleoperated. It is designed to make effective use of the human's abilities within the present state of the art of autonomous systems. Our robotic agents refer to systems which are each equipped with at least one sensing modality and which possess some capability for self-orientation and/or mobility. Our robotic agents are not required to be homogeneous with respect to either capabilities or function. Our research stresses both paradigms and testbed experimentation. Theory issues include the requisite coordination principles and techniques which are fundamental to a cooperative multi-agent system's basic functioning. We have constructed an experimental distributed multi-agent architecture testbed facility. The required modular components of this testbed are currently operational and have been tested individually. Our current research focuses on the agent's integration in a scenario for cooperative material handling.

A hardware testbed for evaluation of adaptive antennas in GSM/UMTS

Abstract: This paper gives a description of a hardware testbed for evaluation of adaptive base station antenna arrays in the GSM/UMTS. The testbed is aimed at the spatial and temporal characterisation of the radio channel and at the performance evaluation of array processing algorithms. The testbed consists of two test mobiles and an 8 element adaptive array receiver. The array processing is implemented by means of real-time digital signal processing hardware.

A cooperative intelligent system for urban traffic problems

Abstract: This paper discusses urban traffic problems and their intelligent solutions. It firstly considers and analyzes the urban traffic problem itself. As a conclusion, a multi-agent paradigm and cooperation between humans and computers are necessary for solving the traffic problems. Such a model is presented to support the argument. Then the paper introduces a cooperative intelligent system for urban traffic problems (COTSCS). A testbed for COTSCS is also described in this paper.

Network control and management of a reconfigurable WDM network

Abstract: This paper describes a set of software and experiments to demonstrate network control and management capabilities for a reconfigurable wavelength-division-multiplexing (WDM) all-optical network. This work is an early prototype implemented in the first year of the DARPA Multiwavelength Optical Networking (MONET) Project. The primary goal of the prototype experiment work was to demonstrate and assess the viability of implementing a WDM network's control and management (NC&M) system over a Common Object Request Broker Architecture (CORBA) compliant reliable distributed platform. Another goal was to demonstrate the viability of using an embedded optical wavelength to support the NC&M system's data communication channels. This early prototype allows us to gain experience and to lay the foundation for our on-going work to develop the full-featured NC&M system in the MONET project's testbed and field trial experiments. This is an important step towards realizing the overall vision of the MONET project in the development of a flexible, reliable, high-capacity, high-performance cost-effective national optical network based on multi-wavelength fiber-optic technology.