Showing papers on "Testbed published in 1994"

Design study for a CDMA-based third-generation mobile radio system

Abstract: This paper focuses on a CDMA design study for future third-generation mobile and personal communication systems such as FPLMTS and UMTS. In the design study, a rigorous top down approach is adopted starting from the most essential objectives and requirements of universal third-generation mobile systems. Emphasis is laid on high flexibility with respect to the implementation of a wide range of services and service bit rates including variable rate and packet services. Flexibility in frequency and radio resource management, system and service deployment, and easy operation in mixed-cell and multioperator scenarios are further important design goals. The system concept under investigation is centered around an open and flexible radio interface architecture based on asynchronous direct-sequence CDMA with three different chip rates of approximately 1, 5, and 20 Mchip/s. The presented CDMA system concept forms the basis for an experimental test system (testbed) which is currently under development. This experimental system concept has been jointly established by the partners in the European RACE project R2020 (CODIT). The paper describes the radio transmission scheme and appropriate receiver principles and presents first performance results based on simulations. >

Virtual integrated software testbed for avionics

Abstract: A virtual integrated software testbed for avionics is disclosed which allows avionics software to be developed on a host computer using a collection of computer programs running simultaneously as processes and synchronized by a central process. The software testbed disclosed uses separate synchronized processes, permits signals from an avionics device to be generated by a simulation running on the host computer or from actual equipment and data bus signals coming from and going to actual avionics hardware is connected to their virtual bus counterparts in the host computer on a real-time basis.

The DTM Gigabit Network

Abstract: DTM is a set of protocols for high-speed networks, based on bandwidth reservation and with support for dynamic reallocation of bandwidth It is designed for real-time multimedia applications and for high-speed computer communication DTM uses a novel medium-access technique and provides a multicast, fast circuit-switched service Several DTM networks can be connected into one large network A prototype implementation and testbed is being constructed

Modeling and control of mobile robots and intelligent vehicles by neural networks

Abstract: This paper introduces the four-wheel-drive vehicle REMI, a testbed developed by SAGEM for research purposes in mobile robotics and intelligent car systems. The motion control architecture of the robot is presented, with an emphasis on the guidance and piloting modules. The latter relies on neural network techniques, and the principles underlying its design are outlined. A robust neural control scheme using an internal model of the process is developed. Experimental results are presented.

CODIT, a testbed project evaluating DS-CDMA for UMTS/FPLMTS

Abstract: The CODIT (Code Division Testbed) project is a research project within the European RACE programme that has the objective to explore the potential of CDMA as an access method for a third generation mobile telephone system. The main activities of the project are: to establish an advanced system concept based on CDMA including an advanced radio interface and an advanced radio subsystem architecture; to design and build a system demonstrator (testbed) comprising test mobile stations, radio base stations, a radio network controller and a channel simulator; and to validate the system concept in laboratory and field tests, as well as with simulations. The results shall be used to improve the concept and to compare with other radio access techniques. The project duration is from February 1992 to September 1995. >

Research on an autonomous vision-guided helicopter

Abstract: Integration of computer vision with on-board sensors to autonomously fly helicopters was researched. The key components developed were custom designed vision processing hardware and an indoor testbed. The custom designed hardware provided flexible integration of on-board sensors with real-time image processing resulting in a significant improvement in vision-based state estimation. The indoor testbed provided convenient calibrated experimentation in constructing real autonomous systems.

Achieving superlinear speedup on a heterogeneous, distributed system

Abstract: The CASA Gigabit Network Testbed, part of NSF and ARPA's Gigabit Project, is investigating whether a metacomputer consisting of widely distributed, heterogeneous supercomputers connected by a high-speed network is viable for large scientific applications. A particular challenge is to determine if such a metacomputer can produce superlinear speedup despite latency and communication overheads. One of the applications in the CASA testbed is a model we developed that couples a global atmosphere model to a world ocean model. Simulations using such coupled general circulation models for climate studies demand considerable computer resources. When distributing such a model, we need to consider the methods for masking latency with computation, the communications bandwidth requirements for different decomposition strategies, the optimal computer architecture for each major phase of the computation, and the effects of latency and communication costs for different decomposition strategies. Here we focus an the last two issues, and demonstrate that choosing the appropriate computer architectures and masking communication with computation can produce superlinear speedup. >

Improving the Performance of Reliable Transport Protocols in Mobile Computing Environments.

Abstract: We explore the performance of reliable data communication in mobile computing environments. Motion across wireless cell boundaries causes increased delays and packet losses while the network learns how to route data to a host's new location. Reliable transport protocols like TCP interpret these delays and losses as signs of network congestion. They consequently throttle their transmissions, further degrading performance. We quantify this degradation through measurements of protocol behavior in a wireless networking testbed. We show how current TCP implementations introduce unacceptably long pauses in communication during cellular handoffs (800 ms and longer), and propose an end-to-end fast retransmission scheme that can reduce these pauses to levels more suitable for human interaction (200 ms). Our work makes clear the need for reliable transport protocols to differentiate between motion-related and congestion-related packet losses and suggests how to adapt these protocols to perform better in mobile computing environments. >

Analysis of Traffic Measurements in the VISTAnet Gigabit Networking Testbed

Abstract: The characterization of ATM traffic is particularly important for developing and validating traffic models for the analysis of congestion control mechanisms, communication network protocols, and architectures for ATM networks. Unfortunately, little is known about the actual behavior of ATM traffic, since few ATM networks have been built and instrumented for measuring traffic. In this paper, we present an analysis of traffic mea1 Supported in part by BellSouth, GTE Corporation, and NSF and DARPA under cooperative agreement NCR-8919038 with the Corporation for National Research Initiative. surements from a medical application called Dynamic Radiation Therapy Planning which runs in a distributed fashion on the VISTAnet gigabit networking test bed. We believe that ours is one of the first measurements of traffic from a real application operating in a high-speed networking environment employing ATM technology. We show that our traffic measurements fit neatly into a proposed hierarchical traffic model which describes the traffic source behavior at different time-scales.

A VR-CELP codec implementation for CDMA mobile communications

Abstract: This paper focuses on the design, implementation and testing of a variable rate (VR) CELP codec aimed to be used in the testbed of one RACE-II project: CoDiT (code division testbed). The project has been conceived to demonstrate the potentiality of CDMA for the UMTS (universal mobile telecommunications system). Because of the flexibility permitted by CDMA to easily convey the information stream over a VR physical channel, the fixed-rate constraint has been removed from the speech coding algorithm design, in order to exploit the time-varying local character of speech. One major feature of the proposed algorithm is the possibility for the average rate to be either source-controlled or network-controlled. This is particularly appealing for cellular communications in order to cope with areas or cells with a high time-varying congestion. >

A High Bandwidth Control System for a Helicopter In-Flight Simulator.

Abstract: The Institute of Flight Mechanics of the DLR has developed a helicopter in-flight simulator, called ATTHeS (Advanced Technology Testing Helicopter System). This in-flight simulator is used for control law design, handling qualities investigations and, in an operational mode, for test pilot training. An explicit model-following control system has been developed which meets the demands of high bandwidth and high flexibility. The essential steps, to obtain a satisfactory status of the control system are described in this paper. The first step was to define an appropriate mathematical model of the testbed BO 105, which includes rotor degrees of freedom to reduce time delays, as these are normally used to describe model deficiencies. The second step was to conduct flight tests with the testbed and then determine the parameters of the defined model by system identification. The third step was the inversion of the above-defined and identified model, and building up the tools for the calculation of the feedforwar...

Sensor fusion for mining robots

Abstract: The use of robots for work in hazardous or unpleasant environments is one factor driving the demand for machines of ever-increasing autonomy and intelligence. Such machines are required to sense and interpret situations, plan strategies, and execute tasks with nearly absolute reliability. Negotiation of complex environments requires the use of a variety of different sensor types and the interpretation of conflicting or missing data, diagnosis of faulty sensors, and the ability to reconfigure a system to work with a partially inoperative sensor suite. This paper focuses on the issues of integration of information from disparate sensor types in the presence of noise and uncertainty. The application is a mobile robot called the autonomous navigation testbed being used at West Virginia University for research in mining robot applications. This paper describes both traditional control techniques and neural network-based methods being used to interpret data from a variety of sensors on the mobile testbed. >

RACE-II Advanced TDMA Mobile Access Project - An Approach for UMTS

Abstract: Third generation mobile radio systems like UMTS/FPLMTS will supply a large variety of voice and data services with variable service bit rates. In Europe investigation and development in this field is supported by the Commission of the European Communities within the RACE-II Mobile Project Line. Within this frame the RACE-II ATDMA project aims to investigate the potential of advanced TDMA systems with respect to the goals of UMTS. Based on propagation measurements, channel modelling and technique studies a realtime and simulated testbed are developed. The performance of this approach is evaluated by simulation, bench and field trials. This contribution gives an overview about the project objectives and current research.

FAST: a functional algorithm simulation testbed

Abstract: We extend the practical range of simulations of parallel executions by "functional algorithm simulation," that is, simulation without actually performing most of the numerical computations involved. We achieve this by introducing a new approach for generating and collecting communication and computation characteristics for a class of parallel scientific algorithms. We describe FAST (Fast Algorithm Simulation Testbed), a prototype system that we developed to implement and test our approach. FAST overcomes some of the difficulties imposed by the very high complexity of interesting scientific algorithms, collects profile information representative of the algorithms rather than the underlying mapping strategies and hardware design choices, and allows a performance assessment of parallel machines with various sites and different interconnection schemes. >

Cooperative multi-agent system for an assembly robotics cell

Abstract: A multi-agent system architecture is described and justified for the sake of its application to an assembly robotics testbed. A blackboard-based agent using a GoalBlackboard/DataBlackboard facility for intra (not inter) agent communication and including knowledge about all the agent's community, is presented as well as its main functionality. Coordination of different agents dynamically playing the roles either of organizers or respondents may lead to the use of either negotiation or client/server protocols for cooperation. Also come cooperative strategies and involved knowledge have been studied, classified and implemented in the robotics testbed enabling a sophisticated agent behavior both in terms of cooperation and local control. A real testbed, whose agents are briefly presented here, working with real-time constraints, has already been implemented and tested in our laboratory.

The Walkstation project on mobile computing

Abstract: Wireless LANs (WLAN) will soon be as popular as Ethernet is today. First products for DECT and 2.4 GHz systems will be available this year. How can these WLANs be connected to the Internet? Which problems arise when mobile users appear as guests in foreign networks? The Walkstation project is realizing a testbed for such a mobile computing environment using a modified set of Internet protocols. These protocols are based on the work of the internet working group on mobile IP (Internet protocol). Other aspects of the Walkstation project cover low power VLSI, cellular infrastructures, network integration, and mobility aware applications.

Design and initial flight test of the Champagne Flyer

Abstract: The design, construction, modeling and test of a highly dynamic experimental tethered aircraft system. This device will serve as a testbed for aggressive maneuvering control systems. >

A realtime testbed for a third generation mobile communication system

Abstract: Third generation mobile radio systems like UMTS or FPLMTS will supply a large variety of voice and data services with variable service bit rates. In Europe investigation and development in this field is supported by the Commission of the European Union within the RACE-II Mobile Project Line. Within this frame the RACE-II ATDMA project aims at investigating the potential of advanced TDMA systems with respect to the goals of UMTS. On the basis of propagation measurements, channel modelling and technique studies two complementary testbeds, a realtime and a simulated testbed, are being developed to evaluate the performance of this approach by simulation, bench, and field trials. The paper briefly describes the project's system model, the relation between this model and the implementation of the realtime testbed. It gives an overview what the goals and the scope of this testbed are and provides a brief introduction into its hardware and software architecture and realisation. >

FPGA prototype queuing module for high performance ATM switching

Abstract: FPGA technology has been used for the development and implementation of a prototype input queuing module of the Illinois Pulsar-based Optical INTconnect (iPOINT) Asynchronous Transfer Mode (ATM) testbed. Pipeline techniques were extensively used to solve timing problems and increase throughput. This prototype queuing module has been fully tested for bandwidth of 100 Mbps. >

Evaluating User Requirements for a Digital Library Testbed

Abstract: The development of widespread capabilities for electronic archival and dissemination of data can be coupled with advances in information systems technology to deliver large volumes of information very fast. Paradoxically, as greater volumes of information become available on electronic information networks, they become increasingly difficult to access. Nowhere is this situation more pressing than in the case of spatial information, which has been traditionally treated as a 'separate' problem by archivists, due to complexities of spatial ordering and indexing. A research project recently funded by NSF will address these problems and implement a working digital library testbed over the next four years. This paper will focus upon one aspect of the testbed, namely evaluating user requirements to inform interface design. The paper presents the evaluation plan, using hypermedia tools to collect real-time interactive logs of user activities on the testbed under design. Conventionally, interactive logging is analyzed by deterministic measures of performance such as counting keystrokes. In this project, the interactive log data will be analyzed using protocol analysis, which has been shown to provide a rich source of information to formalize understanding about semi-structured and intuitive knowledge.

TBONE: TestBed For all-Optical NEtworking

Abstract: The TBONE project is an ARPA-sponsored three-,year collaborative effort between MITRE, Optivision, and TASC. The objectives of the project are twofold: to implement and demonstrate a switched all-optical, multi-user image communications network in an applications environment, and to provide a testbed for developing and demonstrating optical network protocols, and other optical network technology. The testbed network will comprise two optical crossbar switches and two full-duplex single mode dark fiber links spanning the -20km distance between TASC and MITRE. High performance workstations and image servers at the two sites will be linked by the network (see Figure 1).

BED: A multithreaded kernel for embedded systems

Abstract: Embedded systems tend to be event driven. The BED kernel supports an event-action programming model for an embedded systems development environment called Testbed. The kernel features deterministic scheduling and message transfer services.

A Testbed For Rapid Prototyping Of Feature Based Applications

Abstract: The A.S.U. Features Testbed provides an infrastructure for rapid prototyping of feature based applications. The system has an open architecture in which users can define feature libraries for modeling their products and build knowledge bases for a variety of manufacturing applications. The Testbed is organized into two shells: one for feature based product definition, the other for feature based product evaluation or manufacturing planning. The product modeler allows one to integrate features, dimensions, tolerances, assembly data, geometry, topology, and design rules into a unified product description. The applications shell facilitates the creation of knowledge bases and reasoning procedures desired for the applications. In this chapter, we give a brief overview of the system and then discuss several applications that have been implemented. These include GT coding for machining, machinability evaluation, and composite panel forming. The Testbed can be used for two different purposes: (1) Organizations that want to evaluate feature based technology in conjunction with knowledge based applications can quickly do so in this integrated system. (2) feature related techniques and algorithms can be evaluated by software developers. Customization of the Testbed does not require any programming or re-compiling because the system is data-driven.

High speed video compression testbed

Abstract: This paper proposes a parallel processing architecture for a video compression testbed. Experiments for video coding algorithms can be performed and evaluated under this parallel processing architecture. The features of this testbed include (1) simulations of various hardware architectures, (2) test of specialized video compression circuits, and (3) testing ASICs for embedded applications as direct replacement of algorithms that have been certified. We illustrate its implementation, performance evaluation and benchmarking via JPEG/MPEG applications. >

Expanse software for distributed call and connection control

Abstract: The experimental ATM network services environment (EXPANSE) prototype provides an experimental testbed for multimedia multiparty telecommunications services over heterogeneous communications networks. The EXPANSE software architecture supports the functional separation of call and connection control. At the call control layer an object-oriented, transaction-based call model provides for the co-ordination of the negotiations among users for the establishment, modification and disconnection of telecommunications services. The connection control layer provides an object-oriented protocol for the dynamic establishment, modification and release of network connections which include the control and allocation of network resources required for multimedia multiparty services. The EXPANSE software includes an application programming interface (API) to the signalling protocol at the call control level. The API provides a uniform and powerful interface to the call model and allows different applications to co-ordinate the control of local resources and session state.

A distributed data sharing environment for telerobotics

Abstract: We designed and implemented a distributed processing environment for uniformly communicating and sharing information among remotely located robots and human operators. This environment interconnects heterogeneous processors to withstand dynamically changing configurations and communications failures, and to support mixed-mode operation simultaneous teleoperation and autonomous modes. The key design notion is undirected, data-driven communication: the recipients of data rather than the creators define communications paths for well-formed data blocks augmented by descriptive properties. Using this environment, we have implemented both a hierarchical path planner for an intelligent mobile robot operating over a local-area network and a telerobotic testbed that supports long-distance teleoperation.