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A Stable Vision System for Moving Vehicles

IEEE Transactions on Intelligent Transportation Systems 2000年第1期1卷 32-39页

作者： Jin, Jesse S. Zhu, Zhigang Xu, Guangyou Sch. of Comp. Sci. and Engineering University of New South Wales Sydney NSW 2052 Australia Dept. of Comp. Sci. and Technology Tsinghua University Beijing 100084 China Vis. Info. Processing Laboratory Sch. of Comp. Sci. and Engineering University of New South Wales Sydney NSW Australia Computer Science Department University of Massachusetts Amherst MA United States Purdue University West Lafayette IN United States Beckman Institute University of Illinois Urbana-Chamgain IL United States

This paper presents a novel approach to stabilize the output of video camera installed on a moving vehicle in a rugged environment. A 2.5-D interframe motion model is proposed so that the stabilization system can perform in situations where significant depth changes are present and the camera has both rotation and translation. Inertial motion filtering is proposed in order to eliminate the vibration of the video sequences with enhanced perceptual properties. The implementation of this new approach integrates four modules: pyramid-based motion detection, motion identification and 2.5-D motion parameter estimation, inertial motion filtering, and affine-based motion compensation. The stabilization system can smooth unwanted vibrations or shakes of video sequences and achieve real-time speed. We test the system on IBM PC compatible machines and the experimental results show that our algorithm outperforms many algorithms which require parallel pipeline image processing machines.

关键词： Machine vision Vehicles Cameras Filtering Video sequences Motion detection Parameter estimation Motion compensation Real time systems System testing

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Efficient logging and recovery sch.me for lazy release consistent distributed shared memory systems

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Future Generation computer Systems 2000年第3期17卷 265-278页

作者： Park, Taesoon Yeom, Heon Y. Department of Computer Engineering Sejong University 143-747 Seoul Korea Republic of Department of Computer Science Sch. Comp. Sci. Eng. Seoul Natl. U. Seoul Korea Republic of

Checkpointing and logging are widely used techniques to provide fault-tolerance for the distributed systems. However, logging imposes too much overhead on the processing to be a practical solution. In this paper, we propose a low-overhead logging sch.me for the distributed shared memory system based on the lazy release consistency memory model. Unlike the previous sch.mes in which the logging is performed when a new data item is accessed by a process, the stable logging in the proposed sch.me is performed only when a lock grant causes an actual dependency relation between the processes, which significantly reduces the logging frequency. Also, instead of making a stable log of the accessed data items, a process logs stably only some access information, and the accessed data items are saved in the volatile log. For the recovery from a failure, the correct version of the accessed data items can be effectively traced by using the logged access information. As a result, the amount of logged information can also be reduced.

关键词： Distributed computer systems

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Design and implementation of the Lavender micro kernel

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Systems and computers in Japan 2000年第7期31卷 47-55页

作者： Mouri, Koichi Okubo, Eiji Grad. Sch. of Sci. and Engineering Ritsumeikan University Shiga 525-8577 Japan Department of Computer Science Faculty of Science and Engineering Ritsumeikan University Shiga 525-8577 Japan Ritsumeikan University Info. Processing Society of Japan Japan Soc. Software Sci. Technol. Hokkaido University Kyoto University Hitachi Limited Department of Computer Science Kyoto University Department of Computer Science Ritsumeikan University ACM IEEE Computer Society

Micro kernel architecture is widely used in the design of operating systems. However, traditional micro kernels are not easily extensible and so are not very flexible. For example, the granularity of kernel functions does not accord with the users' needs. Moreover, users cannot customize kernel functions easily. Another problem of micro kernels is that system performance is poor due to the overhead of switching address spaces and due to the increased interprocess communication in micro kernels. To address these problems, we have designed and implemented the Lavender micro kernel. Lavender is a micro kernel which can be customized according to application-specific requirements. In order to reduce kernel overhead due to switching address spaces and interprocess communication, Lavender provides users with functionality for process groups and for resident address space. By means of this functionality, the overhead of interprocess procedure calls is reduced to about one-fifth that of other micro kernels. In this paper, the structure and features of Lavender are described. Furthermore, a performance evaluation of process groups and resident address space is presented and the effectiveness of Lavender is discussed.

关键词： computer operating systems

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Custom computing implementation of two-step block matching search algorithm

Custom computing implementation of two-step block matching s...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Yuk Ying Chung Man To Wong N.W. Bergmann Sch. of Comput. Sci. & Comput. Eng. La Trobe Univ. Bundoora Vic. Australia School of Computer Science and Computer Engineering University of New South Wales Sydney Australia

Many fast search block-matching motion estimation (BMME) algorithms has been developed in order to minimize the search positions and speed up the computation but they do not consider how they can be effectively implemented by hardware. We propose a new regular fast search block-matching motion estimation algorithm named two step search (2SS). The 2SS BMME will then be implemented on the SPACE2 custom computer board which consists of up to 8 Xilinx XC6216 fine-grain, sea-of-gate FPGA chips. The experimental and simulation results show that it can have better algorithmic performance and can be implemented by FPGA chips very cost-effectively for video compression applications. Also, the 30 frames per second real time 2SS BMME video compression can be obtained from the SPACE2 custom computer.

关键词： Signal processing algorithms Motion estimation Field programmable gate arrays Video compression Australia Hardware Video sequences computer science Systems engineering and theory Modeling

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Electrostriction effect contribution to high dynamic range optical limiters

Electrostriction effect contribution to high dynamic range o...

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Nonlinear Optics: Materials, Fundamentals and Applications

作者： F.E. Hernandez S.S. Yang V. Dubikovsky E.W. Van Stryland D.J. Hagan Sch. of Opt. Central Florida Univ. Orlando FL USA School of Optics/CREOL and Department of Physics and the School of Electrical Engineering and Computer Science University of Central Florida Orlando FL USA

ISBN: (纸本)1557526451

We show that electrostriction can dominate the nonlinear refraction in CS/sub 2/ for nanosecond pulses. We use this effect in a new cascaded limiter geometry to make an extremely high performance optical limiter. We adopt an approach that uses two quite different nonlinear processes in separate focal planes. In one focal plane, we place a reverse saturable absorber (RSA) material. To protect this, we place a cell of CS/sub 2/ in another focal plane. Due to the strong electrostriction in CS/sub 2/ for ns pulses, the limiter performs well.

关键词： Electrostriction Dynamic range Nonlinear optics Optical refraction Optical sensors Nonlinear optical devices Optical devices Protection Apertures Optical materials

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Development of an NGES-interfaced, Web-based geotechnical site investigation instructional module

Geotechnical Special Publication

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Geotechnical Special Publication 2000年第93期 336-346页

作者： Mooney, Michael A. Bouton, Cyril Gray, Clifton C. Allu, Jitendra Kolar, Randall L. Sch. of Civ. Eng. and Env. Science University of Oklahoma 202 W. Boyd Norman OK 73019 United States Sch. of Mgmt. Information Systems University of Oklahoma 307 W. Brooks Street Norman OK 73019 United States School of Computer Science University of Oklahoma Engineering Laboratory 200 Felgar St. Norman OK 73019 United States

A multimedia tool for virtual geotechnical site investigation is being developed for use on the World Wide Web. The platform-independent module uses the comprehensive and detailed National Geotechnical Experimentation Sites data. A HTML and Java-based front end allows an instructor to easily develop a geotechnical design problem by choosing from seven geotechnical `basemaps' and either selecting a provided structural footprint or entering a unique column sch.dule. Students design a site investigation plan by interactively identifying test types and locations. The module provides a thorough tutorial on laboratory and field testing, a detailed fee sch.dule, and a personalized `shopping cart' that displays the site investigation record visually and documents expenses. The module can be accessed at ***.

关键词： Geotechnical engineering

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Applying evolutionary computation to understanding the insertion behavior of LINE-1 retrotransposons in human DNA

Applying evolutionary computation to understanding the inser...

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Congress on Evolutionary Computation

作者： A. Meade D. Corne R. Sibly Sch. of Comput. Sci. Reading Univ. UK School of Computer Science Cybernetics and Electronic Engineering University of Reading Reading UK School of Animal and Microbial Sciences University of Reading Reading UK

Mobile genetic elements, portions of DNA which are able to copy themselves elsewhere into the genome, have played a substantial role during evolution. One of the most prominent such elements is the LINE-1 retrotransposon, a section of DNA around 6,000 nucleotide bases in length, which is thought to account for about 15% of the current state of the human genome. The mechanism of LINE-1 insertion is rather poorly understood. However, achieving a good understanding of this process is fundamental to understanding natural evolution at the molecular level. We describe a first approach to use evolutionary computation to explore models for the LINE-1 insertion process. A range of findings from standard genome studies are able to suggest the basic parameters and structure of an insertion model. We use an evolutionary algorithm to explore a space of such models.

关键词： Evolutionary computation Genomics Bioinformatics DNA Humans Genetics Proteins Space exploration RNA computer science

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Simulation of transport protocols over wireless communication networks

Simulation of transport protocols over wireless communicatio...

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Simulation Winter Conference

作者： H. ElArag M. Bassiouni Sch. of Electr. Eng. & Comput. Sci. Univ. of Central Florida Orlando FL USA School of Electrical Engineering and Computer Science University of Central Florida Orlando FL USA

We describe a general-purpose communication network simulator that we designed to examine the performance of transport protocols over wireless networks. The general-purpose simulator can be used to study various aspects of performance of communication networks. In particular, we use it to examine, evaluate and predict the performance of wireless networks under a variety of the most commonly used transport protocols. We also examine the use of newly suggested protocols specifically designed for wireless networks. We present our models for each protocol and discuss various performance measures that can be studied using our simulator. These measures are hard to evaluate with analytical models.

关键词： Transport protocols Wireless communication Wireless networks Network servers Computational modeling Communication networks Base stations Bit error rate Wireless application protocol Mobile computing

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Resource-conscious customization of CORBA for CAN-based distributed embedded systems

Resource-conscious customization of CORBA for CAN-based dist...

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International Symposium on Object-Oriented Real-Time Distributed Computing

作者： Kimoon Kim Gwangil Geon Seongsoo Hong Sunil Kim Taehyung Kim Sch. of Electr. Eng. Seoul Nat. Univ. South Korea Electrical Engineering and ERC-ACI Seoul National University Seoul South Korea Department of Computer Science and Engineering Hanyang University Ansan Kyunggi South Korea

While recently emerging middleware technologies such as CORBA and DCOM address the complexity of distributed programming, they cannot be directly applied to distributed control system design due to their excessive resource demand and inadequate communication models. We propose a new CORBA design for CAN-based distributed embedded control systems. Our design goal is to minimize its resource need and make it support group communication without losing the IDL (interface definition language) level compliance to the OMG standards. To achieve this, we develop a transport protocol on the CAN and a group communication sch.me based on the well-known publisher/subscriber model. The protocol effectively realizes subject-based addressing and supports anonymous publisher/subscriber communication. We also customize the method invocation and message passing protocol, referred to as the general inter-ORB protocol (GIOP), of CORBA so that CORBA method invocations are efficiently serviced on a low-bandwidth network such as the CAN. This customization includes packed data encoding and variable-length integer encoding for compact representation of IDL data types. The new CORBA design clearly demonstrates that it is feasible to use CORBA in developing distributed embedded systems on real-time networks possessing severe resource limitations.

关键词： Distributed control Encoding Middleware Communication system control Control systems Communication standards Transport protocols Message passing Embedded system Real time systems

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A performance comparison of hybrid and conventional MAC protocols for wireless networks

A performance comparison of hybrid and conventional MAC prot...

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IEEE Conference on Vehicular Technology (VTC)

作者： I. Chlamtec A. Farago A.D. Myers V.R. Syrotiuk G. Zaruba Sch. of Eng. & Comput. Sci. Texas Univ. Dallas TX USA Center for Advanced Telecommunications Systems and Services Erik Jonsson School of Engineering and Computer Science University of Texas Dallas USA

Ad hoc networks consist of a group of wireless nodes that dynamically form a multihop network via shared communication channels. For each node, channel access is managed by a media access control (MAC) protocol. MAC protocols can be classified into three broad categories: contention, allocation, and hybrid protocols that combine the contention and allocation access sch.mes. ADAPT is a hybrid protocol comprised of two component protocols-an allocation protocol that provides stable operation under strenuous network conditions (e.g., high load and nodal degree), and a contention protocol that dynamically manages the available bandwidth. This paper presents a simulation study that compares the performance of several conventional and hybrid MAC protocols. We examine the relative performance of each protocol under equivalent network conditions, and show that the overall performance of the ADAPT protocol is superior. We also discuss the ability of each protocol to support delay sensitive applications, such as voice, video, and multimedia transmission.

关键词： Media Access Protocol Wireless application protocol Wireless networks Access protocols Peer to peer computing Ad hoc networks sch.duling Spread spectrum communication Bandwidth Delay

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