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Probabilistic algorithms, integration, and empirical evaluation for disambiguating multiple selections in frustum-based pointing

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Journal of Multimedia 2006年第3期1卷 1-12页

作者： Schmidt, Greg Brown, Dennis G. Tomlin, Erik B. Edward Swan, J. Baillot, Yohan 3D Virtual and Mixed Environments Lab U.S. Naval Research Laboratory United States ITT Industries Advanced Engineering and Sciences United States Department of Computer Science and Engineering Mississippi State University United States

There are a few fundamental pointing-based user interface techniques for performing selections in 3D environments. One of these techniques is ray pointing, which makes selections by determining intersections of objects along a single ray cast from the user. This technique is susceptible to inaccuracy of the user interface tracking technology and user noise (e.g., jittery hand, see actual viewing ray in Figure 1 (bottom) and how it misses the object when error is factored in). Another technique is the frustum-based (or equivalent cone-based) approach which casts a frustum from the user into the 3D scene. Selections are made by performing intersections of objects with the frustum. This technique resolves the imprecision associated with the ray pointing technique (see how the lightly shaded cone in Figure 1 (bottom) still intersects the object), but may produce multiple ambiguous selections as shown in Figure 2. This paper presents probabilistic selection algorithms and integration schemes that address some of the ambiguities associated with the frustum-based selection technique. The selection algorithms assign probabilities that the user has selected particular objects using a set of low-level 3D intersection-based selection techniques and the relationship of the objects in a hierarchical database. Final selections are generated by integating the outputs from each selection algorithm using one of several weighting schemes. We implemented the selection algoithms and weighting schemes within our distributed augmented reality (AR) and virtual reality (VR) architecture. Next, we performed several experiments to empirically evaluate the probabilistic selection techniques and integration schemes. Our results show that the combined selection and integration algorithms are effective at disambiguating multiple selections. This paper thoroughly describes the architecture, experiments, and results. © 2006 ACADEMY PUBLISHER.

关键词： Augmented reality

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On the quality of service of failure detectors based on control theory

On the quality of service of failure detectors based on cont...

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International Conference on advanced Information Networking and Applications (AINA)

作者： N. Xiong Yan Yang Jianxun Chen Yanxiang He The State Key Lab of Software Engineering Computer School of Wuhan University China Japan Advanced Institute of Science and Technology School of Information Science Japan Computer Science and Technology School Wuhan University of Science and Technology China

The detection of failures is a fundamental issue for fault tolerance in distributed systems. Recently, many people have come to realize that failure detection ought to be provided as some form of generic service, similar to IP address lookup. However, this has not been successful so far; one of the reasons being the fact that classical failure detectors were not designed to satisfy several application requirements simultaneously. More specifically, traditional implementations of failure detectors are often tuned for running over local networks and fail to address some important problems found in wide-area distributed systems with a large number of monitored components. In this paper, we study the quality of service (QoS) of failure detectors. We first present a novel failure detector scheme combined with control theory that can help in solving or optimizing some problems. Furthermore, this paper discusses the design and analysis of implementing a scalable failure detection service for such large wide-area distributed systems considering dynamically adjusting the heartbeat streams, so that it satisfies the bottleneck router requirements. We further show how the online failure detector control algorithm can be used to design a controller, analyze the theoretical aspects of the proposed algorithm and verify its agreement. Simulation results show the efficiency of our scheme in terms of high utilization of the bottleneck link, fast response and good stability of the bottleneck router buffer occupancy as well as of the controlled sending rates. In conclusion, the new failure detector algorithm provides a better QoS.

关键词： Quality of service Detectors Control theory Failure analysis Algorithm design and analysis Fault detection Fault tolerant systems Condition monitoring Heart beat Stability

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A control-design-based solution to robotic ecology: Autonomy of achieving cooperative behavior from a high-level astronaut command

A control-design-based solution to robotic ecology: Autonomy...

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作者： Wang, Jing Qu, Zhihua Ihlefeld, Curtis M. Hull, Richard A. Department of Electrical and Computer Engineering University of Central Florida Orlando FL 32816 United States Kennedy Space Center FL 32899 United States Lockheed Martin Missiles and Fire Control 5600 Sand Lake Rd. MP-450 Orlando FL 32819 United States School of Electrical and Computer Science University of Central Florida IEEE AIAA University of Central Florida Department of Electrical and Computer Engineering National Aeronautics and Space Administration Kennedy Space CenterKennedy Space Center Applied Physics Lab. Advanced Concepts Business Unit Science Applications International Corporation SAIC IEEE Control System Society

In this paper, we propose a cooperative control strategy for a group of robotic vehicles to achieve the specified task issued from a high-level astronaut command. The problem is mathematically formulated as designing the cooperative control for a general class of multiple-input-multiple-output (MIMO) dynamical systems in canonical form with arbitrary but finite relative degrees such that the outputs of the overall system converge to the explicitly given steady state. The proposed cooperative control for individual vehicle only need to use the sensed and communicated outputs information from its local neighboring vehicles. No fixed leader and time-invariant communication networks are assumed among vehicles. Particularly, a set of less-restrictive conditions on the connectivity of the sensor/communication networks are established, under which it is rigorously proven by using the newly found nice properties of the convergence of sequences of row stochastic matrices that the cooperative objective of the overall system can be achieved. Simulation results for a group of vehicles achieving a target and surrounding a specified object in formation are provided to support the proposed approach in this paper.

关键词： Robotics

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Design and Analysis of a Self-Tuning Proportional and Integral Controller for Active Queue Management Routers to Support TCP Flows

Design and Analysis of a Self-Tuning Proportional and Integr...

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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： N. Xiong X. Defago X. Jia Y. Yan Y. He State Key Laboratory of Software Engineering Computer School Wuhan University of China China School of Information Science Japan Advanced Institute of Science and Technology Japan PRESTO Japan Science and Technology Agency Japan School of Information Science Japan Advanced Institute of Science and Technology Nomi Ishikawa Japan Member of IEEE Communication Society Computer School Wuhan University Department of Computer Science City University of Hong Kong Kowloon Hong Kong China School of Computer Science and Technology Wuhan University of Science and Technology China The State Key Lab of Software Engineering Computer School Wuhan University

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Technology validation: NMP ST8 Dependable Multiprocessor Project

Technology validation: NMP ST8 Dependable Multiprocessor Pro...

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IEEE Conference on Aerospace

作者： J.R. Samson J. Ramos A.D. George M. Patel R. Some Honeywell Aerospace Advanced Technology Clear Water FL USA Tandel Systems Limited Liability Company Clear Water USA Department of Electrical and Computer Engineering University of Florida Gainesville FL USA Jet Propulsion Lab California Institute of Technology Pasadena CA USA

Current and future space-based processing applications are requiring, and will require, increasing amounts of onboard processing capability. One way to achieve a high level of processing capability is through the use of COTS (commercial-off-the-shelf) high-performance processors. While state-of-the-art COTS processors are exhibiting adequate total integrated dose (TID) performance to meet the requirements of the natural space radiation environment, single event upsets (SEUs) caused by galactic cosmic rays and solar protons remain a problem. Traditional approaches to mitigate the SEU problem involve fixed redundancy schemes such as self checking pairs (SCP) or triple modular redundancy (TMR). While effective in mitigating the effects of SEUs, use of these techniques comes at a high price, 100% overhead for SCP, and 200% overhead for TMR, particularly when such a level of protection is not needed. In such cases, it would be beneficial to be able to convert that overhead into useful mission processing capability or power reduction. The idea behind Dependable Multiprocessor is to sense the environment and configure the processing system appropriately to maximize the computational performance density, i.e., the computational performance to power ratio, available to the mission. The goal of the Dependable Multiprocessor Project is to provide spacecraft/payload processing capability 10times - 100times what is available today, enabling heretofore unrealizable levels of science and autonomy. To date, Dependable Multiprocessor (DM) technology has been developed as part of NASA's New Millennium Program (NMP) ST8 (Space Technology 8) project. The objective of this NMP ST8 effort is to combine high-performance, fault tolerant, COTS-based cluster processing and fault tolerant middleware in an architecture and software framework capable of supporting a wide variety of mission applications. Dependable Multiprocessor development is continuing as one of the four selected ST8 flight e

关键词： Space technology Single event upset Single event transient Redundancy Fault tolerance Cosmic rays Protons Power system protection Space vehicles Payloads

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Interactive media server with media synchronized RAID storage system

Interactive media server with media synchronized RAID storag...

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15th International Workshop on Network and Operating Systems Support for Digital Audio and Video, NOSSDAV 2005

作者： Lim, Seung-Ho Jeong, Yo-Won Park, Kyu-Ho Computer Engineering Research Lab. EECS Korea Advanced Institute of Science and Technology

We propose an efficient placement algorithm and per-disk prefetching method to effectively support interactive operations in the media server. Our placement policy is incorporated with an encoder having a special bitcount control scheme that repeatedly tunes quantization parameters to adjust the bitcounts of video frames. This encoder can generate coded frames whose sizes are synchronized with the RAID stripe size, so that when various fast-forward levels are accessed we can reduce the seek and rotational latency and enhance the disk throughput of each disk in the RAID system. In the experimental results, the proposed placement policy and bitrate control scheme can significantly improve the average service time, which can enlarge the capacity of the interactive media server. Copyright 2005 ACM.

关键词： Interactive computer systems

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A new approach for service-oriented architecture

A new approach for service-oriented architecture

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ITI 3rd International Conference on Information and Communications Technology, ICICT 2005 - Enabling Technologies for the New Knowledge Society

作者： Talaei-Khoei, Amir Sheriffian, Amir Hesam Akbari, Mohammad Kazem Verdom, Javad Farzaneh Advanced ITDevelopment Lab. Department of Computer Engineering and IT Amirkabir University of Technology Iran

ISBN: (纸本)0780392701

Service providing as an important activity in service-oriented architecture, which is the most popular architecture for applications of distributed environments needs a change to obtain better efficiency, so in this paper we will present neighbor providing and Extended Neighbor Providing (ENP) methods, which are apply the neighborhood computing in traditional methods. As evaluation of these methods we will use the efficiency, scalability, and reliability metrics obtained from the results of omnet++ simulation and we measured the users' satisfactions with their opinions about the quality of implemented ENP system.

关键词： computer architecture

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Survivable GMPLS networks with QoS guarantees

Survivable GMPLS networks with QoS guarantees

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作者： Luo, Y. Ansari, N. Advanced Networking Lab Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ 07102 United States

A scheme is proposed to provide multiple QoS guarantees for survivable generalised multiprotocol label switching (GMPLS) networks. The shared risk link group (SRLG) information is considered to provide failure-independent protection. Based on the problem formulation, the service level agreement (SLA) parameters, such as the expected recovery failure probability, the expected recovery time and the expected signal loss are analysed to reveal the bound of the backup path length. Under the constraint of such a backup path length limit, a heuristic algorithm is further proposed for online path configuration. The simulation results demonstrate that the heuristic algorithm provides recovery quality guaranteed backup paths with high bandwidth multiplexing gain. © IEE, 2005.

关键词： Telecommunication networks

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Delayed locking technique for improving real-time performance of embedded Linux by prediction of timer interrupt

Delayed locking technique for improving real-time performanc...

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11th IEEE Real-Time and Embedded Technology and Applications Symposium, RTAS 2005

作者： Lee, Jupyung Park, Kyu-Ho Computer Engineering Research Lab. EECS Korea Advanced Institute of Science and Technology Daejeon 305-701 Korea Republic of

In this paper, we propose a new technique, called a delayed locking technique, to improve the real-time performance of embedded Linux. The proposed technique employs the rule that entering a critical section is allowed only if the operation does not disturb the future execution of the real-time application. To execute this rule, we introduce the concepts of timer interrupt prediction and lock hold time acquisition. In addition, we designed and implemented a new high-resolution timer that is simple, yet efficient. We implemented the prototype on Linux 2.4.18. Experimental results show that the worst-case OS latency of real-time process is reduced to 23% of the original one, at the expense of slow-down of the non-real-time process by 20%. Though we focus only on embedded Linux, our technique is useful for all kinds of real-time operating systems in which the critical section is significantly long. © 2005 IEEE.

关键词： Real time systems

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Random beamforming in MIMO systems exploiting efficient multiuser diversity

Random beamforming in MIMO systems exploiting efficient mult...

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2005 IEEE 61st Vehicular Technology Conference -VTC 2005 - Spring Stockholm: Paving the Path for a Wireless Future

作者： Kim, Eun Yong Chun, Joohwan Scientific Computing Lab. Department of Electrical Engineering and Computer Science Korea Advanced Institute of Science and Technology Daejeon Korea Republic of

We propose a new random beamforming technique in forward link multiuser MIMO systems that exploits efficient multiuser diversity and spatial multiplexing gain. The common channels are allocated to more than one user simultaneously and multiple antennas at the receivers are used for interference nulling, resulting in higher throughput and reduced average waiting time. We show that the throughput of the proposed scheme outperforms the upper bound of the conventional scheme. © 2005 IEEE.

关键词： Communication channels (information theory)

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