• Title, Summary, Keyword: Active control

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Implementation of an Autonomous Vehicle System for Urban Environment (도심 환경에 적합한 자율주행차량 시스템의 구현)

  • Han, Sungjoon;Kim, Seongjae;Jang, Ho Hyeok;Moon, Beomseok;Park, Seonghyeon;Lee, Young-Sup
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.621-622
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    • 2019
  • 본 논문은 도심 환경하에서 운행 가능한 자율주행차량 시스템의 구현 방안에 대해 다루고 있다. 현대자동차가 주최한 2019 대학생 자율주행 경진대회는 도심 환경을 재현한 K-City 에서 열렸고, 도심 환경에서 발생할 수 있는 돌발 장애물 인지, 공사 구간 우회, 교차로 신호등 인지, 사고 차량 회피, 응급 차량에게 차선 양보 및 톨게이트 통과 등의 6 개의 미션을 자율주행차량이 무인운전으로 수행하는 것이었다. 이 대회를 위해 본 연구팀에서 개발한 자율주행 시스템은 리웍된 실제 차량에 탑재되어 대회장의 모든 주행 미션을 성공적으로 수행하였다.

Pole Assignment for Structural Active Control

  • Vongchavalitkul, Sanguan
    • 제어로봇시스템학회:학술대회논문집
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    • pp.5-7
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    • 2004
  • Significant progress has been achieved in the active control of civil-engineering structures, not only in the control algorithm, but also in control testing of the scaled model and full-scale building. At the present time, most algorithms used in the active control of civil engineering structures are based on the various active control techniques. In this paper represents active control method, by using pole assignment for reducing structural vibration under excited load. Numerical simulations are performed to assess the effectiveness of pole assignment control system. The relative displacement of structure system is significantly reduced.

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The Study of technique to find and prove vulnerabilities in ActiveX Control (ActiveX Control 취약점 검사 및 검증 기법 연구)

  • Sohn, Ki-Wook;Kim, Su-Yong
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.15 no.6
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    • pp.3-12
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    • 2005
  • To provide visitors with the various services, Many web sites distribute many ActiveX controls to them because ActiveX controls can overcome limits of HTML documents and script languages. However, PC can become dangerous if it has unsecure ActiveX controls, because they can be executed in HTML documents. Nevertheless, many web sites provide visitors with ActiveX controls whose security are not verified. Therefore, the verification is needed by third party to remove vulnerabilities in ActiveX controls. In this paper, we introduce the process and the technique to fad vulnerabilities. The existing proof codes are not valid because ActiveX controls are different from normal application and domestic environments are different from foreign environments. In this paper, we introduce the technique to prove vulnerabilities in ActiveX control.

The Study on the Security Model for ActiveX Control Management through Security Authentication (보안 인증을 통한 ActiveX Control 보안 관리 모델에 관한 연구)

  • Park, Sung-Yong;Moon, Jong-Sub
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.19 no.6
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    • pp.113-119
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    • 2009
  • In recent years, to provide visitors with the various and dynamic services, many ActiveX Controls are developed and distributed in most of the web sites such as e-Government Internet banking Portal in Korea. However, unsecure ActiveX Controls may be critical security threats on Internet User. Although hacking incidents increase sharply for these vulnerable ActiveX Controls, there are not enough national security actions or policies. Thus, in this paper we propose the technical method to design 'Security model for ActiveX Control Managemnet through Security Authentication' to be able safe and useful security management in three aspects of development distribution using.

A semi-active stochastic optimal control strategy for nonlinear structural systems with MR dampers

  • Ying, Z.G.;Ni, Y.Q.;Ko, J.M.
    • Smart Structures and Systems
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    • v.5 no.1
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    • pp.69-79
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    • 2009
  • A non-clipped semi-active stochastic optimal control strategy for nonlinear structural systems with MR dampers is developed based on the stochastic averaging method and stochastic dynamical programming principle. A nonlinear stochastic control structure is first modeled as a semi-actively controlled, stochastically excited and dissipated Hamiltonian system. The control force of an MR damper is separated into passive and semi-active parts. The passive control force components, coupled in structural mode space, are incorporated in the drift coefficients by directly using the stochastic averaging method. Then the stochastic dynamical programming principle is applied to establish a dynamical programming equation, from which the semi-active optimal control law is determined and implementable by MR dampers without clipping in terms of the Bingham model. Under the condition on the control performance function given in section 3, the expressions of nonlinear and linear non-clipped semi-active optimal control force components are obtained as well as the non-clipped semi-active LQG control force, and thus the value function and semi-active nonlinear optimal control force are actually existent according to the developed strategy. An example of the controlled stochastic hysteretic column is given to illustrate the application and effectiveness of the developed semi-active optimal control strategy.

Active Control of External Noise Radiated From Duct Using Sound Intensity (음향 인텐시티를 이용한 관 외부 방사 소음의 능동 제어)

  • 강성우;김양한
    • Journal of KSNVE
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    • v.7 no.3
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    • pp.427-437
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    • 1997
  • Mean active intensity based active control for the cancellation of radiated noise out of the duct exit is studied. The active intensity control strategy is drerived based on the relation of the exterior sound field out of the duct termination and interior sound field of the duct. One of the characteristics of this control strategy is that the control performance can be maintained regardless of the sensor loction, compared with the conventional local pressure control methods at either interior downstream or exterior field positions. It is also suggested that the digital filtering for the active intensity control can be achieved by time-domain filtered-x LMP (Lest-Mean-Product) adaptive algorithm. Experiments for an open-ended duct are performed to compare the active intensity control performance with conventional pressure control one. Active control experiment of local sound pressure is conducted by widely used filtered-x LMS adaptive Algorithm and active intensity control implementaion uses the derived filter d-x LMP algorithm. It is shown that the exterior sound fileds was much better observable by sensing of the active intensity than by just sound pressure. It is also demonstrated that the global control performance of external field by acoustic intensity is superior to the conventional sound pressure control performance.

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Active tendon control of suspension bridges

  • Preumont, Andre;Voltan, Matteo;Sangiovanni, Andrea;Mokrani, Bilal;Alaluf, David
    • Smart Structures and Systems
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    • v.18 no.1
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    • pp.31-52
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    • 2016
  • The paper first reviews the theory of active tendon control with decentralized Integral Force Feedback (IFF) and collocated displacement actuator and force sensor; a formal proof of the formula giving the maximum achievable damping is provided for the first time. Next, the potential of the control strategy for the control of suspension bridges with active stay cables is evaluated on a numerical model of an existing footbridge; several configurations are investigated where the active cables connect the pylon to the deck or the deck to the catenary. The analysis confirms that it is possible to provide a set of targeted modes with a considerable amount of damping, reaching ${\xi}=15%$. Finally, the control strategy is demonstrated experimentally on a laboratory mock-up equipped with four control stay cables equipped with piezoelectric actuators. The experimental results confirm the excellent performance and robustness of the control system and the very good agreement with the predictions.

A Robust Semi-active Suspension Control Law (반능동 현가시스템의 Robust 제어 법칙)

  • Yi, K.S.;Suh, M.W.;Oh, T.I.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.6
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    • pp.117-126
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    • 1994
  • This paper deals with a robust semi-active control algorithm which is applicable to a semi-active suspension with a multi-state damper. Since the controllable damping rates are discrete in case of a multi-state semi-active damper, the desired damping rate can not be produced exactly even if force-velocity relations of a multi-state semi-active damper is completely known. In addition, damping characteristics of the semi-active dampers are different from damper to damper. A robust nonlinear control law based on sliding control is developed. The main objective of the proposed control strategies is to improve ride quality by tracking the desired active force with a multi-state damper of which the force-velocity relations are "not" completely known. The performance of th proposed semi-active control law is numerically compared to those of the control law based on a bilinear model and a passive suspension. The proposed control algorithm is robust to nonlinear characteristics and uncertainty of the force-Velocity relations of multi-state dampers.

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Chaotic particle swarm optimization in optimal active control of shear buildings

  • Gharebaghi, Saeed Asil;Zangooeia, Ehsan
    • Structural Engineering and Mechanics
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    • v.61 no.3
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    • pp.347-357
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    • 2017
  • The applications of active control is being more popular nowadays. Several control algorithms have been developed to determine optimum control force. In this paper, a Chaotic Particle Swarm Optimization (CPSO) technique, based on Logistic map, is used to compute the optimum control force of active tendon system. A chaotic exploration is used to search the solution space for optimum control force. The response control of Multi-Degree of Freedom (MDOF) shear buildings, equipped with active tendons, is introduced as an optimization problem, based on Instantaneous Optimal Active Control algorithm. Three MDOFs are simulated in this paper. Two examples out of three, which have been previously controlled using Lattice type Probabilistic Neural Network (LPNN) and Block Pulse Functions (BPFs), are taken from prior works in order to compare the efficiency of the current method. In the present study, a maximum allowable value of control force is added to the original problem. Later, a twenty-story shear building, as the third and more realistic example, is considered and controlled. Besides, the required Central Processing Unit (CPU) time of CPSO control algorithm is investigated. Although the CPU time of LPNN and BPFs methods of prior works is not available, the results show that a full state measurement is necessary, especially when there are more than three control devices. The results show that CPSO algorithm has a good performance, especially in the presence of the cut-off limit of tendon force; therefore, can widely be used in the field of optimum active control of actual buildings.

Active Vibration Control Experiment of Cantilever Using Active Linear Actuator for Active Engine Mount (능동 엔진 마운트 제어용 Active Linear Actuator를 이용한 외팔보 능동진동제어 실험)

  • Yang, Dong-Ho;Kwak, Moon-K.;Kim, Jung-Hoon;Park, Woon-Hwan;Sim, Ho-Seok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.12
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    • pp.1176-1182
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    • 2010
  • Vibrations caused by automobile engine are absorbed mostly by a passive-type engine mount. However, user specifications for automobile vibrations require more stringent conditions and higher standard. Hence, active-type engine mount have been developed to cope with such specifications. The active-type engine mount consists of sensor, actuator and controller where a control algorithm is implemented. The performance of the active engine mount depends on the control algorithm if the sensor and actuator satisfies the specification. The control algorithm should be able to suppress persistent vibrations caused by the engine which are related to engine revolution. In this study, three control algorithms are considered for suppressing persistent vibrations, which are the positive position feedback control algorithm, the strain-rate feedback control algorithm, and the modified higher harmonic control algorithm. Experimental results show that all the control algorithms considered in this study are effective in suppressing resonant vibrations but the modified higher harmonic controller is the most effective controller for non-resonant vibrations.