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Parallel computing and mathematical optimization :proceedings of the Workshop on Parallel algorithms and Transputers for Optimization, held at the University of Siegen, FRG, November 9, 1990 ./

Parallel computing and mathematical optimization :proceeding...

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1991年

作者： Workshop on Parallel algorithms and Transputers for Optimization(1990 :University of Siegen)Manfred Grauer Dieter B. Pressmar (Eds.). Grauer Manfred Pressmar Dieter B.

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Parallel algorithms for Dynamic Shortest Path Problems

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International Transactions in Operational Research 2002年第3期9卷 279-302页

作者： Chabini, Ismail Ganugapati, Sridevi Department of Civil and Environmental Engineering Massachusetts Institute of Technology United States

The development of intelligent transportation systems (ITS) and the resulting need for the solution of a variety of dynamic traffic network models and management problems require faster-than-real-time computation of shortest path problems in dynamic networks. Recently, a sequential algorithm was developed to compute shortest paths in discrete time dynamic networks from all nodes and all departure times to one destination node. The algorithm is known as algorithm DOT and has an optimal worst-case running-time complexity. This implies that no algorithm with a better worst-case computational complexity can be discovered. Consequently, in order to derive algorithms to solve all-to-one shortest path problems in dynamic networks, one would need to explore avenues other than the design of sequential solution algorithms only. The use of commercially-available high-performance computing platforms to develop parallel implementations of sequential algorithms is an example of such avenue. This paper reports on the design, implementation, and computational testing of parallel dynamic shortest path algorithms. We develop two shared-memory and two message-passing dynamic shortest path algorithm implementations, which are derived from algorithm DOT using the following parallelization strategies: decomposition by destination and decomposition by transportation network topology. The algorithms are coded using two types of parallel computing environments: a message-passing environment based on the parallel virtual machine (PVM) library and a multi-threading environment based on the SUN Microsystems Multi-Threads (MT) library. We also develop a time-based parallel version of algorithm DOT for the case of minimum time paths in FIFO networks, and a theoretical parallelization of algorithm DOT on an ‘ideal’ theoretical parallel machine. Performances of the implementations are analyzed and evaluated using large transportation networks, and two types of parallel computing platforms: a distr

关键词： computer algorithms Dynamic networks Dynamic shortest paths Intelligent transportation systems Parallel and distributed computing

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From Logic Design to Logic Programming: Theorem Proving Techniques and P-functions /

From Logic Design to Logic Programming: Theorem Proving Tech...

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1987年

作者： Snyers Dominique.Dominique Snyers Andre Thayse. Thayse Andre.

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Augmentation Index Derived from Peripheral Arterial Tonometry Correlates with Cardiovascular Risk Factors

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CARDIOLOGY RESEARCH AND PRACTICE 2011年第2011期2011卷 253758-253758页

作者： Patvardhan, Eshan Heffernan, Kevin S. Ruan, Jenny Hession, Michael Warner, Patrick Karas, Richard H. Kuvin, Jeffrey T. Tufts Med Ctr Div Cardiol Boston MA 02111 USA Tufts Med Ctr Mol Cardiol Res Inst Boston MA 02111 USA

Background. Augmentation index (AIx) is traditionally obtained from pressure waveforms via arterial applanation tonometry. We sought to evaluate the association between AIx obtained from peripheral arterial tonometry (PAT) with cardiovascular risk factors (CRF) and coronary artery disease (CAD). Methods. 186 patients were enrolled in the study. The presence or absence of CRFs and CAD was assessed in each subject. AIx was calculated by an automated algorithm averaging pulse wave amplitude data obtained via PAT. Central blood pressures were assessed in a subset of patients undergoing clinically indicated cardiac catheterization. Results. An association was observed between AIx and age, heart rate, systolic blood pressure, mean arterial pressure, pulse pressure, body weight and body mass index. AIx was significantly lower in patients with <3 CRFs compared to those with >5 CRFs (P - .02). CAD+ patients had significantly higher AIx compared to CAD-patients (P = .008). Area under the ROC curve was 0.604 (P < .01). In patients undergoing cardiac catheterization, after adjusting for age, height and heart rate, AIx was a significant predictor of aortic systolic and pulse pressures (P < .05) Conclusion. AIx derived from PAT correlates with cardiac risk factors and CAD. It may be a useful measure of assessing overall risk for coronary artery disease.

关键词： CARDIOVASCULAR diseases risk factors TONOMETRY CORONARY heart disease CARDIAC catheterization computer algorithms BLOOD pressure

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Fast and efficient algorithms in computational electromagnetics / Weng Cho Chew ... [et al.], editors.

Fast and efficient algorithms in computational electromagnet...

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2001年

作者： Weng Cho Chew ... [et al.] editors.

ISBN: (纸本)1580531520

From the Publisher: Here's a cutting-edge resource that brings you up-to-date with all the recent advances in computational electromagnetics. You get the most-current information available on the multilevel fast multipole algorithm in both the time and frequency domains, as well as the latest developments in fast algorithms for low frequencies and specialized structures, such as the planar and layered media. These algorithms solve large electromagnetics problems with shorter turn around time, using less computer memory. Complex problems that once required a supercomputer to solve, can now be solved on a workstation or personal computer with the innovative methods taught in this resource. The book introduces you to new advances in the perfectly matched layer absorbing boundary conditions, and offers you a thorough understanding of error analysis of numerical methods, fast-forward and inverse solvers for inverse problems, hybridization in computational electromagnetics, and asymptotic waveform evaluation.

关键词： computer algorithms ELECTROMAGNETICS

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Low Cost X4 Platform to Study Control algorithms

Low Cost X4 Platform to Study Control Algorithms

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International Conference on Unmanned Aircraft Systems

作者： D. Lara G. Romero D. Flores L. Ramirez A. Zuniga C. Pegard R. Abdelhamid E. Alcorta UAMRR-Universidad Autonoma de Tamaulipas Laboratoire MIS Universite de Picardie Jules Verne Universidad Autonoma de Nuevo Leon

ISBN: (纸本)9781479923779

In this paper, we present the design of an autopilot embedded system applied to control a four rotor mini helicopter, called X4-flyer. The main goal is to achieve a stable flight, controlling the vehicle attitude;this is done using two control strategies: a linear PD control and nonlinear nested saturations control. The onboard system uses a simplified architecture and the main processor has a structured program to handle the data acquisition, and calculates the control to send actuators correction to get a desired set point. Real time experiments, in a pivoted platform, show that the autopilot is a reliable low cost platform.

关键词： Automatic pilots learning control computer algorithms host processor STRUCTURAL APPLICATION Data Collection Methods Proportional derivative control Platform Set of points Standing Orders

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A Resonant Bidirectional DC-DC Converter for Aerospace Applications

A Resonant Bidirectional DC-DC Converter for Aerospace Appli...

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2011 IEEE Energy Conversion Congress and Exposition (ECCE 2011)

作者： Alireza Safaee Alireza Bakhshai Praveen Jain Queen's Centre for Energy and Power Electronics Research (ePOWER) Queen's University Kingston Ontario Canada

ISBN: (纸本)9781457705427;9781457705410

A wide-range input-output bidirectional dc-dc power converter suitable for power rating of several kilowatts is introduced in this paper. This converter provides a high frequency operation with zero voltage switching (ZVS) for all the switches, with no auxiliary circuitry or increased component stresses. The transformer leakage inductance is used as the resonant inductor. The proposed control algorithm includes a combination of variable frequency control and pulse width modulation methods. The control provides the minimum current for any active power level, with no compromise in zero voltage switching, through precise selection of the control variables of frequency, phase shift and duty cycle. The experimental results verify the feasibility and performance of the proposed topology.

关键词： Aerospace applications Zero voltage switching DC-DC power convertors Power rating Bidirectional DC to DC converters DC converter Frequency control zero voltage operating frequency control variable computer algorithms Switches

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Modeling of a Dual Actuator System and its Control Algorithm Preventing Saturation of Fine Actuator

Modeling of a Dual Actuator System and its Control Algorithm...

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IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM)

作者： Duckjune Kim Kyung-Tae Nam Sang Hoon Ji Sang Moo Lee Department of Applied Robot Technology Korea Institute of Industrial Technology (KITECH) Ansan 426-791 South Korea

ISBN: (纸本)9781457708381

This paper discusses the design of control structure of dual actuator system, which is considered as DISO system, for high precision manufacturing stage. It proposes that PA tracks error signal between estimated coarse position and output coarse position at control sample to prevent saturation. Estimators are designed for both fine and coarse actuator plants to derive input signal to PA and state-feedback gain is defined by LQR. Dynamic model is defined by Newton's second law and coupling dynamics is considered for control structure. Experimental results demonstrate that unnecessary movement of PA during the transient response is reduced resulting in enhanced overshoot and settling time of the DSA system.

关键词： actuator system computer algorithms Nylons Control Architecture feedback gain fine fine Modeling setting time input signal TRANSIENT RESPONSE actuators Precision manufacturing ERROR SIGNAL

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Mobile Experimental Platform for the Development of Environmentally Interactive Control algorithms towards the Implementation on a Walking Humanoid Robot

Mobile Experimental Platform for the Development of Environm...

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Joint international symposium on robotics

作者： Giulio Milighetti Janko Petereit Helge-Bjoern Kuntze Fraunhofer Institute of Optronics System Technologies and Image Exploitation Karlsruhe Germany

ISBN: (纸本)9781617387197

In the framework of the long term Collaborative Research Center SFB 588 "Humanoid Robots" the robot ARMAR III has to manage different basic skills in a highly dynamic environment. They mainly take place in the area close to the robot and require especially its upper body including head, arms and hands. However, during the last project phase the development has been mainly focused on basic skills which have to be accomplished mainly in a wider range and require also walking capability (e.g. carrying a tray). In order to investigate in advance such new environmentally interactive control algorithms, an adequate development platform is required. The mobile experimental platform developed with this goal at Fraunhofer IOSB consists of an upper body including various existing robot components like torso, head, arms and hands, as well as a lower body represented by a mobile robot. A Stewart platform provides then the functionality of a human hip connecting upper and lower body. This hexapod structure is the central element of the proposed platform because it is responsible for a motion of the upper body, that emulates the oscillations of a human gangway. Therefore, the most important steps of its design process will be discussed in this paper. In order to demonstrate the feasibility of the platform, a case study optimizing the gaze control of a humanoid robot head will be presented.

关键词： Humanoid robots upper body computer algorithms interactive control basic skill Platform lower body Robot development platform Mobile Hand central element Life skills Research centers

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Control Strategy for Two-Stage Photovoltaic Power Converter During Simultaneous Grid Faults and Irradiance Change

Control Strategy for Two-Stage Photovoltaic Power Converter ...

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IEEE International Conference on Power Electronics and Motion Control

作者： Ivana Isakov Vladimir Katic Ivan Todorovic Stevan Grabic Faculty of Technical Sciences University of Novi Sad

ISBN: (纸本)9781538641996

The development of the distributed power energy sources has resulted in the increase of the number of the power converters in the distribution network. The control strategies of these converters have to be improved in order to maximize the power production and satisfy the grid code requirements, especially in abnormal grid conditions. In this paper control algorithm for a photovoltaic (PV) system connected to the grid through two-stage power converter is analyzed considering normal grid conditions and grid faults, as well as sudden change of the illumination intensity on the PV side. The proposed solution features several key improvements comparing to the existing solutions, such as smooth transition between the modes of operation, fast response to the grid disturbances, provision of several grid support strategies and instantaneous limitation of the phase currents. The control algorithm is tested in the hardware-in-the-loop testing environment and the results that verify the proposed control strategy are given.

关键词： control strategy power conversion unit grids Converters illumination intensity Grid Power production Phase current Energy sources Grid computing Power grids smooth transition computer algorithms PHOTOVOLTAIC Power (Psychology)

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