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SUPPORTING DISTRESS SIGNALS OVER LOW EARTH ORBIT MOBILE SATELLITE SYSTEMS FOR EMERGENCY INFORMATION ACQUISITION

International Journal of Information Acquisition 2014年第3N04期9卷

作者： GAMAL A. HUSSEIN MOSTAFA A. NOFAL MOAWAD I. DESSOUKY OSAMA ALY ORABY WALEED AL-HANAFY ABD EL-NASER A. MOHAMED IBRAHIM M. ELDOKANY EL-SAYED M. EL-RABAIE SALEH A. ALSHEBEILI FATHI E. ABD EL-SAMIE Engineering Sector of Broadcast Egyptian Radio and Television Union Egypt Department of Electronics and Electrical Communications Engineering Faculty of Electronic Engineering Menoufia University Menouf 32952 Egypt Computer Engineering Department College of Computer Science and Information Systems Taif University Kingdom of Saudi Arabia Department of Electrical Engineering Faculty of Engineering Albaha University Kingdom of Saudi Arabia Electrical Engineering Department KACST-TIC in Radio Frequency and Photonics for the e-Society (RFTONICS) King Saud University Kingdom of Saudi Arabia KACST-TIC in Radio Frequency and Photonics for the e-Society (RFTONICS) King Saud University Kingdom of Saudi Arabia

Low earth orbit (LEO) satellite systems allow a broad range of services to be provided using small, lightweight, cellular-like portable telephones. Exploiting LEO satellites to support distress signals for aircrafts, ships and international travelers is explored in the current paper. A multi-service priority-oriented algorithm is proposed for handling voice, data and emergency signals over LEO satellites. The emergency signal is privileged with service priority so that rescue operation can be carried out as soon as possible. The priority mechanism includes channel reservation as well as joining a queue if no free channel is available as long as the request is roaming in the handover area. In addition, a simplified but efficient approach is suggested for locating the object of an imminent danger situation. As LEO satellites are non-geostationary, the visible period of each spot-beam is small. Consequently, a teletraffic model, that accommodates the mobility of spot-beams as well as the resulting handover rate, is developed in order to gauge the performance of the proposed algorithm. Numerical results for access denying and service-dropping rates are presented for nominal system parameters.

关键词： LEO satellite-cellular telephone-distress signal-voice-data-emergency

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Modified SOM based intelligent semi-autonomous navigation system

Modified SOM based intelligent semi-autonomous navigation sy...

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2012 9th International Conference on High Capacity Optical Networks and Enabling Technologies, HONET 2012

作者： Ul Hassan, Shabih Ahmed, Bilal Shaukat, Bilal Paracha, Habib Ur Rehman Malik, Usman Qaiser, Saad Anwar, Nabeel Ayaz, Yasar Department of Electrical Engineering School of Electrical Engineering and Computer Science National University of Science and Technology Sector H-12 Islamabad 44000 Pakistan Department of Robotics and Artificial Intelligence School of Mechanical and Manufacturing Engineering National University of Science and Technology Sector H-12 Islamabad 44000 Pakistan Biomedical Engineering Department School of Mechanical and Manufacturing Engineering National University of Science and Technology Sector H-12 Islamabad 44000 Pakistan

ISBN: (纸本)9781467315722

The fundamental problem in today's world when robots are becoming a part of daily routine is getting them to move from one desired place to another without any problem and collision. In doing so a robot needs to perceive its environment to efficiently navigate through it. The navigation is possible only if the robot differentiates between different scenarios around it in real time. In this paper we present a semi-autonomous navigation strategy designed for low throughput interfaces. The task is to minimize the user input by intelligently interpreting and executing the commands. Analyzing the environment in real time, the robot selects the most probable action using collision free steering techniques which employ the Self Organizing Map in cooperation with Artificial Potential Field, in which both the user and an intelligent robot co-exist. The performance of the proposed navigation algorithm is confirmed with computer simulations and experiments using the Pioneer 3-AT mobile robot. © 2012 IEEE.

关键词： Collision avoidance

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Set-based actuator fault diagnosis in Lure systems

Set-based actuator fault diagnosis in Lure systems

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8th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes, SAFEPROCESS 2012

作者： Seron, María M. De Doná, José A. Richter, Jan H. School of Electrical Engineering and Computer Science University of Newcastle Callaghan NSW 2308 Australia Siemens AG Industry Sector Gleiwitzer Str. 555 90475 Nuremberg Germany

ISBN: (纸本)9783902823090

In this paper we present a method for actuator fault detection and identification in Lure systems. The Lure plant is controlled by an observer-based feedback tracking controller, designed for the nominal (fault-free) system. A residual signal is constructed from measurable estimation errors associated with the nominal observer. Faults are diagnosed by on-line contrasting the residual signal trajectories against a set of values that the residuals can be shown to attain under healthy or faulty operation. These values are obtained via set-invariance analysis of the system closed-loop trajectories. © 2012 IFAC.

关键词： Fault detection

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Virtual actuator for Lure systems with Lipschitz-continuous nonlinearity

Virtual actuator for Lure systems with Lipschitz-continuous ...

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8th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes, SAFEPROCESS 2012

作者： Richter, Jan H. Seron, María M. De Doná, José A. Siemens AG Industry Sector Gleiwitzer Str. 555 90475 Nürnberg Germany School of Electrical Engineering and Computer Science University of Newcastle Callaghan NSW 2308 Australia

ISBN: (纸本)9783902823090

In this paper, we extend virtual actuators to Lure systems with Lipschitz-continuous nonlinear characteristic. Virtual actuators are used to reconfigure control laws after the occurrence of actuator failures. They have been developed for linear, Hammerstein-Wiener, and piecewise affine systems and are now made available for Lure systems. Lure systems, which consist of linear dynamics with nonlinear internal feedback, are useful for representing, among others, mechanical systems with friction. We provide sufficient stability conditions for the reconfigured closed-loop system that are also useful for finding the virtual actuator parameters, and evaluate the method by means of an example. © 2012 IFAC.

关键词： Closed loop systems

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Monolithic single output dual wavelength LED

Monolithic single output dual wavelength LED

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IEEE Photonics Conference (IPC)

作者： Abdullah J. Zakariya Patrick LiKamWa Information Technology & Communication Sector MOI Kuwait Safat Kuwait Department of Electrical Engineering and Computer Science Central Florida Blvd Orlando FL

A monolithic dual-wavelength LED based on selectively intermixed QW structure is fabricated and investigated experimentally. The device has a single output beam of two independently controlled intensities whose peak e... 详细信息

关键词： Light emitting diodes Periodic structures Color Optical device fabrication Gallium arsenide

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Monolithic optical beam steering over selectively intermixed GaAs/AlGaAs QW laser structure

Monolithic optical beam steering over selectively intermixed...

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Frontiers in Optics, FIO 2012

作者： Zakariya, Abdullah J. Ho, Tony LiKamWa, Patrick CREOL The College of Optics and Photonics United States Department of Electrical Engineering and Computer Science University of Central Florida 4000 Central Florida Blvd. Orlando FL 32816 United States Information Technology and Communication Sector MOI Kuwait P.O.Box 1250 Safat 71655 Kuwait

We demonstrate monolithic integration of optical beam steering over semiconductor laser. Carrier-induced guiding is utilized to confine and steer an optical beam laterally over two nearby quantum well regions selectiv... 详细信息

ISBN: (纸本)9781557529565

关键词： Semiconductor quantum wells

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Set-based Actuator Fault Diagnosis in Lure Systems

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IFAC Proceedings Volumes 2012年第20期45卷 234-239页

作者： María M. Seron José A. De Doná Jan H. Richter Centre for Complex Dynamic Systems and Control (CDSC) School of Electrical Engineering and Computer Science The University of Newcastle Callaghan NSW 2308 Australia Siemens AG Industry Sector Gleiwitzer Str. 555 90475 Nuremberg Germany

关键词： Lure systems fault detection and identification invariant sets

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Virtual actuator for Lure systems with Lipschitz-continuous nonlinearity

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IFAC Proceedings Volumes 2012年第20期45卷 222-227页

作者： Jan H. Richter María M. Seron José A. De Doná Siemens AG Industry Sector Gleiwitzer Str. 555 90475 Nürnberg Germany Centre for Complex Dynamic Systems and Control (CDSC) School of Electrical Engineering and Computer Science The University of Newcastle Callaghan NSW 2308 Australia

关键词： Fault-tolerant control reconfigurable control virtual actuator Lure systems

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Bank of virtual actuators for fault tolerant control

Bank of virtual actuators for fault tolerant control

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ISBN: (纸本)9783902661937

We propose an actuator fault tolerant control scheme based on a bank of virtual actuators (VA), with the novel feature that the virtual actuators implicitly integrate both fault detection and isolation (FDI) and controller reconfiguration (CR) tasks. The bank of VAs operates in closed-loop with an observer-based tracking controller designed for a nominal (fault free) model of the plant. We consider abrupt actuator faults ranging over a finite cover. Each VA is designed to operate appropriately in combination with the nominal controller to achieve correct CR for a particular fault situation in the considered range. A switching rule that engages the suitable VA from the bank is based on sets defined for measurable residual signals constructed directly from the virtual actuators signals. The overall scheme is shown to guarantee closed-loop boundedness and setpoint tracking under all considered fault situations. The method is applied to an example of aircraft lateral control. © 2011 IFAC.

关键词： Controllers

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Bank of Virtual Actuators for Fault Tolerant Control

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IFAC Proceedings Volumes 2011年第1期44卷 5436-5441页

Abstract We propose an actuator fault tolerant control scheme based on a bank of virtual actuators (VA), with the novel feature that the virtual actuators implicitly integrate both fault detection and isolation (FDI) and controller reconfiguration (CR) tasks. The bank of VAs operates in closed-loop with an observer-based tracking controller designed for a nominal (fault free) model of the plant. We consider abrupt actuator faults ranging over a finite cover. Each VA is designed to operate appropriately in combination with the nominal controller to achieve correct CR for a particular fault situation in the considered range. A switching rule that engages the suitable VA from the bank is based on sets defined for measurable residual signals constructed directly from the virtual actuators signals. The overall scheme is shown to guarantee closed-loop boundedness and setpoint tracking under all considered fault situations. The method is applied to an example of aircraft lateral control.

关键词： Fault tolerant control fault detection and isolation controller reconfiguration virtual actuators actuator faults invariant sets

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