• Title/Summary/Keyword: performance-robustness

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Modal synthesis of missle autopilot control law (미사일 자동 조종 제어 법칙의 형태합성)

  • 박노웅;배준경;박종국
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.547-549
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    • 1987
  • The purpose of this paper is to present an efficient and practical method for a Hissle autopilot design problem. The method emphasizes on the use of a modern design technique to classical flight control specifications and the trade-off between dynamic performance and robustness of the Missle autopilot control system.

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Web-Based On-Line Thermal Performance Analysis System for Turbine Cycle of Nuclear Power Plant (온라인 웹기반 원전 터빈 사이클 열성능 분석 시스템)

  • Choi KiSang;Choi KwangHee;Ji MoonHak;Hong SeungYeol;Kim SeongKun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.3 s.234
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    • pp.409-416
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    • 2005
  • We need to develop a on-line thermal performance analysis system for nuclear power plant to determine performance status and heat rate of turbine cycle. We have developed PERUPS(PERformance Upgrade System) to aid the effective performance analysis of turbine cycle. Procedures of performance calculation are improved using several adaptations from standard calculation algorithms based on PTC(Performance Test Code). Robustness in the on-line performance analysis is increased by verification & validation scheme for measured input data. The system also provides useful web interfaces for performance analysis such as graphic heat balance of turbine cycle and components, turbine expansion lines, automatic generation of analysis report. The system was successfully applied for YongGwang nuclear plant unit #3,4.

Highly Reliable Digital Image Watermarking Based on HVS and DWT (HVS 및 DWT 기반의 고신뢰 디지털 영상 워터마킹)

  • 권성근;권기구;하인성;권기룡;이건일
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.12A
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    • pp.2100-2108
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    • 2001
  • A digital image watermarking algorithm is proposed that uses human visual system (HVS) and discrete wavelet transform (DWT). In this algorithm, an image is decomposed into four-level by DWT which reveals the characteristics of the human eyes and watermark is embedded into DWT coefficients using HVS. For robustness, the lowest level subbands which represent the highest frequency component are excluded in watermark embedding step and watermark is embedded into the perceptually significant coefficients (PSCs) of the rest subbands. PSCs of the baseband are selected according to the amplitude of the coefficients and PSCs of the high frequency subbands are selected by successive subband quantization (SSQ). Watermark is embedded into the PSCs of the baseband and high frequency subbands by Weber\`s law and spatial masking effect, respectively, for the invisibility and robustness. We tested the performance of the proposed algorithm compared with the conventional watermarking algorithm by computer simulation. Experimental results show that the proposed watermarking algorithm produces a better invisibility and robustness than the conventional algorithm.

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Robustness Estimation for Power and Water Supply Network : in the Context of Failure Propagation (피해파급에 대한 고찰을 통한 전력 및 상수도 네트워크의 강건성 예측)

  • Lee, Seulbi;Park, Moonseo;Lee, Hyun-Soo
    • Korean Journal of Construction Engineering and Management
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    • v.19 no.3
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    • pp.33-42
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    • 2018
  • In the aftermath of an earthquake, seismic-damaged infrastructure systems loss estimation is the first step for the disaster response. However, lifeline systems' ability to supply service can be volatile by external factors such as disturbances of nearby facilities, and not by own physical issue. Thus, this research develops the bayesian model for probabilistic inference on common-cause and cascading failure of seismic-damaged lifeline systems. In addition, the authors present network robustness estimation metrics in the context of failure propagation. In order to quantify the functional loss and observe the effect of the mitigation plan, power and water supply system in Daegu-Gyeongbuk in South Korea is selected as case network. The simulation results show that reduction of cascading failure probability allows withstanding the external disruptions from a perspective of the robustness improvement. This research enhances the comprehensive understanding of how a single failure propagates to whole lifeline system performance and affected region after an earthquake.

WATERMARKING OF DIGITAL IMAGES BASED ON PRINCIPAL COMPONENT ANALYSIS

  • Thai, Hien-Duy;Zensho Nakao;Chen, Yen-Wei
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.484-487
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    • 2003
  • A new domain PCA-based approach to watermarking is presented. This method is applied to digital images to embed and detect a watermark. The performance of PCA approach is compared to traditional frequency domain watermark models. Simulation shows the performance of the proposed method with excellent result against image cropping and robustness against some attacks such as additive noise, filtering and jpeg compression.

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Generator Excitor Control Using Robust Control (강인제어이론을 이용한 발전기 여자 시스템)

  • Hong, Hyun-Mun;Jeong, Su-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.53 no.4
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    • pp.161-165
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    • 2004
  • This thesis proposes a robust controller introducing the $H_{\infty}$ control theory, one of the robust control theories that can obtain desired control performance while ensuring robustness for the uncertainty and disturbance contained in the power system. This thesis also proposes an improved digital exciter control system for a synchronized generator using a digitally designed controller. Simulation to verify the usefulness of the proposed method was carried. Results show that the proposed control system manifests excellent control performance compared to existing control systems.

Improved Blind Multipath Estimation for Long Code DS-CDMA

  • Yu Qian;Bi Guoan;Zhang Gaonan
    • Journal of Communications and Networks
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    • v.7 no.3
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    • pp.278-283
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    • 2005
  • This paper proposes a blind channel estimation scheme for long code direct sequence code division multiple access (DS­CDMA) systems with multipath fading channels. This scheme combines the advantages of Toeplitz displacement and correlation matching methods to achieve improved performance. The basic idea is to remove the effects of noise and interferences with Toeplitz displacement operation and then estimate the multi path channel parameters with the correlation matching method. Simulation results are presented to show that the proposed scheme provides better MSE performance and robustness against the near-far problem.

Design of Neural Network Adaptive Control Law for Aircraft System Including Uncertainty

  • Kim, You-Dan;Shin, Dong-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.125.3-125
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    • 2001
  • Recently, aircraft is designed to have high maneuverable at high angle of attack. However, it is very hard to obtain the accurate dynamic model for the high performance, because aerodynamic characteristics are nonlinear and include a lot of uncertainties. Therefore, nonlinear controller without considering uncertainties may degrade the control system performance. On this paper, to overcome these defects, the neural networks based adaptive nonlinear controller is proposed making use of the backstepping technique. Neural networks are implemented to guarantee robustness to uncertainties caused by aerodynamic coefficients variation. The main feature of the proposed controller is that the adaptive controller is developed under the assumption ...

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A study on the controller design of gun/turret servo system (포/포탑 구동 시스템의 제어기 설계에 관한 연구)

  • 이석재;정오진;이교일
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.718-723
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    • 1992
  • A hydraulic gun/turret servo system requires fast and robust controller performance because of severe operating condition and precise target tracking objective. Digital controllers are able to satisfy this requirement due to high speed electronic device. The purpose of this study is to compare with pre-EPU with new-designed optimal, adaptive controllers by simulating nonlinear hydraulic simulation program. The designed digital controller shows good tracking performance and robustness to disturbance.

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Robust LQ control of magnetically levitation systems with a combined lift and guidance using loop-shaping techniques (루프형성 기법을 이용한 편심배치방식 자기부상 시스템의 강인 LQ 제어)

  • 박전수;김종식
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.747-753
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    • 1992
  • The modeling and control design schemes are developed for maglev systems with a combined lift and guidance. First, bond graph techniques are applied for modeling these multi-energy domain systems more logically and systematically. And the stability loop via pole placement and the performance loop via loop-shaping LQ control are designed. The suggested controller satisfies the required characteristics of stability and performance simultaneously. Finally, the robustness of the synthesized maglev control system is evaluated for the variations of air gap and vehicle mass through computer simulation.

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