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Control performance of active-passive composite tuned mass damper

SMART MATERIALS & STRUCTURES 1998年第5期7卷 637-653页

作者： Nishimura, I Yamada, T Sakamoto, M Kobori, T Kajima Corp Kobori Res Complex Minato Ku Tokyo 107 Japan

This paper reviews an active control algorithm adopted for an active-passive composite tuned mass damper, which is a unique vibration control device equipped into an office building in Tokyo in 1993. The main purpose of this device is to subdue the response motion of tall buildings under random disturbances such as wind pressures and small earthquakes. The main topics in this paper are: (1) the principle of the acceleration feedback algorithm, (2) the expected control performance, (3) the multi-modal control algorithm, (4) the observed performance of the applications using the algorithm.

关键词： office buildings stochastic disturbance Wing loading active control Tall buildings vibration control DAMPER algorithms Tokyo acceleration feedback control performance computer algorithms

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Approach to optical interference fringes reduction in diode laser absorption spectroscopy

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APPLIED PHYSICS B-LASERS AND OPTICS 2007年第3期87卷 523-530页

作者： Persson, L. Andersson, F. Andersson, M. Svanberg, S. Lund Univ Div Atom Phys S-22100 Lund Sweden Lund Univ Ctr Math Sci S-22100 Lund Sweden

The advantage of a new scheme for balanced detection has been investigated to reduce the influence of optical interference fringes when performing diode laser gas absorption spectroscopy employing lock-in amplifiers and pigtailed lasers. The influence of the fringes has been reduced by comparing the lock-in 2 f signal due to the gas sample with that of a reference beam. The frequency regions outside the absorption feature have been used to obtain information on the interference fringe impact on the signal of interest. We have demonstrated an efficient way to reduce the influence of such fringes by employing this technique combined with non-linear signal processing methods. The different steps of the algorithm are presented. In the experimental arrangement presented, a reduction of the optical interference fringes by about 10 times is achieved, as demonstrated in measurements on molecular oxygen around 761 nm. The new technique is compared with an analog technique for balanced detection and certain advantages of the computer algorithm are pointed out. In particular, the emerging field of gas spectroscopy in scattering solid media strongly benefits from the technique presented.

关键词： semiconductor lasers laser diodes spectroscopic techniques interference interference pattern Semiconductor lasers gas spectroscopy interference Diode Laser Light interference tunable diode laser absorption spectroscopy spectroscopic techniques reference beam computer algorithms

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Decentralized control of tall buildings

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STRUCTURAL DESIGN OF TALL AND SPECIAL BUILDINGS 2006年第2期15卷 153-170页

作者： Rofooei, FR Monajemi-Nezhad, S Sharif Univ Technol Dept Civil Engn Tehran Iran

The response of large-scale building structures can be actively reduced using an appropriate control algorithm and a number of actuators and sensors located within the building. This paper presents a decentralized control approach for controlling the response of tall buildings. The proposed method aims to divide the structural model into several substructures, each one performing on its own controller algorithm. This approach has already been used in controlling large-scale systems such as power transmission systems and space structures. An instantaneous optimal control scheme is used as the control algorithm with different control feedbacks such as velocity feedback alone and displacement and velocity feedback. The stability issue of this method is addressed. A numerical example is used to investigate the performance of the proposed method compared to the case with centralized control. Copyright (c) 2005 John Wiley & Sons, Ltd.

关键词： actuators Standing Orders Structural Models Substructures numerical example computer algorithms Decentralized Buildings power transmission system INTEGRATED SHIP CONTROL velocity feedback decentralised control control response

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Static and dynamic job scheduling with communication aware policy in cluster computing

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computerS & ELECTRICAL ENGINEERING 2013年第2期39卷 690-696页

作者： Madheswari, A. Neela Banu, R. S. D. Wahida KMEA Engn Coll Dept Informat Technol Aluva India Govt Coll Engn Salem India

Parallel jobs submitted to processors should be efficiently scheduled to achieve high performance. Early scheduling strategies for parallel jobs make use of either space-sharing approach or time-sharing approach. The scheduling strategy proposed in this work, makes use of both the policies for parallel jobs while scheduling under clusters. Static and dynamic scheduling algorithms were developed for communication intensive jobs. The algorithms are used to handle different types of jobs such as serial, parallel and mixed jobs. For performance evaluation, the workload from Grid5000 platform is considered. The main objective is to achieve performance and power improvement. The dynamic scheduling algorithm with communication aware policy gives better performance when compared to static scheduling algorithm that is tested under the given workload. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： PRODUCTION scheduling COMMUNICATION WORKSTATION clusters (computer systems) PERFORMANCE evaluation computer algorithms COMPARATIVE studies

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A new adaptive backstepping control algorithm for motion control systems - an implicit and symbolic computation approach

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INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING 2003年第1期17卷 19-32页

作者： Yu, JT Chang, J Rockwell Sci Thousand Oaks CA 91360 USA

A new adaptive integral backstepping control algorithm for motion control systems is proposed. The design approach is non-conventional in that it only implicitly incorporates error states into a design Lyapunov function and computes time derivative of the Lyapunov function symbolically to the point of getting parameter estimate update laws on which desirable structures are imposed. The closed-loop error system turns out to be linear and time-varying and can be reformulated as a linear-non-linear cascade system. Uniform exponential stability or absolute stability can be achieved. The design is robust against system parameter variations. The effectiveness and robustness of the control algorithm are verified by numerical examples. Copyright (C) 2002 John Wiley Sons, Ltd.

关键词： Implicit cascade systems error system Motion Control System Liapunov function design approach absolute stability adaptive backstepping control computer algorithms time derivative

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Distributed consensus-based security mechanisms in cognitive radio mobile ad hoc networks

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IET COMMUNICATIONS 2012年第8期6卷 974-983页

作者： Tang, H. Yu, F. R. Huang, M. Li, Z. Def R&D Canada Ottawa ON Canada Carleton Univ Dept Syst & Comp Engn Ottawa ON K1S 5B6 Canada Carleton Univ Sch Math & Stat Ottawa ON K1S 5B6 Canada

Cognitive radios (CRs), which are capable of sensing its surrounding environment and adapting its internal parameters, have been considered in mobile ad hoc networks (MANETs). The area of security in CR-MANETs has received far less attention than other areas. However, some distinct characteristics of CRs introduce new non-trivial security risks to CR-MANETs. In this article, the authors study spectrum sensing data falsification (SSDF) attacks to CR-MANETs, in which intruders send false local spectrum sensing results in cooperative spectrum sensing, and it will result in wrong spectrum sensing decisions by CRs. The authors present a novel bio-inspired consensus-based cooperative spectrum sensing scheme to counter SSDF attacks in CR-ANETs. Their scheme is based on recent advances in consensus algorithms that have taken inspiration from self-organising behaviour of animal groups such as birds, fish, ants, honeybees and others. Unlike the existing schemes, there is no need for a common receiver to do the data fusion for reaching the final decision to counter SSDF attacks. The scheme has self-configuration and self-maintenance capabilities. Moreover, in order to further improve the security of CR-MANETs, the authors present an authentication scheme using identity (ID)-based cryptography with threshold secret sharing. Simulation results are presented to show the effectiveness of the proposed schemes.

关键词： computer network security COGNITIVE Abilities Test AD hoc networks (computer networks) computerS -- Access control computer algorithms SYSTEM identification

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Hardware-software design and validation framework for wireless LAN modems

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IEE PROCEEDINGS-computerS AND DIGITAL TECHNIQUES 2004年第3期151卷 173-182页

作者： Drosos, C Bisdounis, L Metafas, D Blionas, S Tatsaki, A Papadopoulos, G INTRACOM SA GR-19002 Athens Greece Univ Patras Dept Elect & Comp Engn Appl Elect Lab Patras 26500 Greece

The implementation and validation of a 5-GHz wireless LAN modem based on the HIPERLAN/2 standard is presented. In modern wireless communication systems, there is a demand for higher flexibility and more computational efficiency. Therefore the emphasis of this work is on the hardware-software structure of the developed modem and its processes, in order to offer a good balance of these requirements. In order to efficiently design and validate the behaviour of the modem, a behavioural model was developed in UML (Unified Modelling Language) as a part of the overall HIPERLAN/2 system's model. The processes of the modem were implemented in an instruction-set processor and custom hardware, combining the advantages of both software and hardware implementations. The communication between the software and hardware parts of the modem is achieved through a specialised programmable interface unit. The UML-based model of the actual HIPERLAN/2 system is used in order to validate the modem's behaviour, using scenarios from in-field usage (such as transfer of data using FTP or HTTP). Furthermore, the validation of the algorithms implemented within the modem was based on this system model, and performed through the use of a custom-validation framework. This framework produces patterns for the validation of the modem's algorithms, at three different development phases (algorithmic, HDL, FPGA-based prototyping), derived from the simulation of the system model in a consistent and automatic way. Implementation figures and co-simulation results for the developed wireless LAN modem are also given.

关键词： MODEMS WIRELESS LANs DATA transmission systems computer algorithms MODULATORS (Electronics) ELECTRONICS ELECTRONIC systems

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Adaptive EWMA Method Based on Abnormal Network Traffic for LDoS Attacks

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-11页

作者： Tang, Dan Chen, Kai Chen, XiaoSu Liu, Huiyu Li, Xinhua Huazhong Univ Sci & Technol Sch Comp Sci & Technol Wuhan 430074 Hubei Peoples R China

The low-rate denial of service (LDoS) attacks reduce network services capabilities by periodically sending high intensity pulse data flows. For their concealed performance, it is more difficult for traditional DoS detection methods to detect LDoS attacks;at the same time the accuracy of the current detection methods for LDoS attacks is relatively low. As the fact that LDoS attacks led to abnormal distribution of the ACK traffic, LDoS attacks can be detected by analyzing the distribution characteristics of ACK traffic. Then traditional EWMA algorithm which can smooth the accidental error while being the same as the exceptional mutation may cause some misjudgment;therefore a new LDoS detection method based on adaptive EWMA (AEWMA) algorithm is proposed. The AEWMA algorithm which uses an adaptive weighting function instead of the constant weighting of EWMA algorithm can smooth the accidental error and retain the exceptional mutation. So AEWMA method is more beneficial than EWMA method for analyzing and measuring the abnormal distribution of ACK traffic. The NS2 simulations show that AEWMA method can detect LDoS attacks effectively and has a low false negative rate and a false positive rate. Based on DARPA99 datasets, experiment results show that AEWMA method is more efficient than EWMA method.

关键词： DENIAL of service attacks computer algorithms DISTRIBUTION (Probability theory) INTERNET traffic ADAPTIVE computing systems

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A Novel Concept for Guidance and Control of Spacecraft Orbital Maneuvers

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INTERNATIONAL JOURNAL OF AEROSPACE ENGINEERING 2016年第Pt.2期2016卷 7695257.1-7695257.1页

作者： Dentis, Matteo Capello, Elisa Guglieri, Giorgio Politecn Torino Dept Mech & Aerosp Engn Corso Duca Abruzzi 24 I-10129 Turin Italy Politecn Torino Dept Mech & Aerosp Engn CNR IEIIT Corso Duca Abruzzi 24 I-10129 Turin Italy

The purpose of this paper is the design of guidance and control algorithms for orbital space maneuvers. A 6-dof orbital simulator, based on Clohessy-Wiltshire-Hill equations, is developed in C language, considering cold gas reaction thrusters and reaction wheels as actuation system. The computational limitations of on-board computers are also included. A combination of guidance and control algorithms for an orbital maneuver is proposed: (i) a suitably designed Zero-Effort-Miss/Zero-Effort-Velocity (ZEM/ZEV) algorithm is adopted for the guidance and (ii) a linear quadratic regulator (LQR) is used for the attitude control. The proposed approach is verified for different cases, including external environment disturbances and errors on the actuation system.

关键词： Activation reaction wheels orbital maneuvers Space simulators computer algorithms Guidance C language spacecraft control linear quadratic regulators

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A Nonlinear Goal Programming Model for University Admission Capacity Planning with Modified Differential Evolution Algorithm

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-13页

作者： El-Quliti, Said Ali Ragab, Abdul Hamid Mohamed Abdelaal, Reda Mohamed, Ali Wagdy Mashat, Abdulfattah Suliman Noaman, Amin Yousef Altalhi, Abdulrahman Helal King Abdulaziz Univ Fac Engn Ind Engn Dept Jeddah 21589 Saudi Arabia King Abdulaziz Univ Informat Syst Dept Fac Comp & Informat Technol Jeddah 21589 Saudi Arabia Univ Jeddah Dept Stat Fac Sci Jeddah 21589 Saudi Arabia King Abdulaziz Univ Deanship Admiss & Registrat Jeddah 21589 Saudi Arabia King Abdulaziz Univ Comp Sci Dept Fac Comp & Informat Technol Jeddah 21589 Saudi Arabia King Abdulaziz Univ Informat Technol Dept Fac Comp & Informat Technol Jeddah 21589 Saudi Arabia

This paper proposes a nonlinear Goal Programming Model (GPM) for solving the problem of admission capacity planning in academic universities. Many factors of university admission capacity planning have been taken into consideration among which are number of admitted students in the past years, total population in the country, number of graduates from secondary schools, desired ratios of specific specialties, faculty-to-students ratio, and the past number of graduates. The proposed model is general and has been tested at King Abdulaziz University (KAU) in the Kingdom of Saudi Arabia, where the work aims to achieve the key objectives of a five-year development plan in addition to a 25-year future plan (AAFAQ) for universities education in the Kingdom. Based on the results of this test, the proposed GPM with a modified differential evolution algorithm has approved an ability to solve general admission capacity planning problem in terms of high quality, rapid convergence speed, efficiency, and robustness.

关键词： NONLINEAR systems GOAL programming (Mathematics) UNIVERSITY & college admission CAPACITY requirements planning DIFFERENTIAL evolution (computer science) computer algorithms

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