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The performance analysis of multiple sliding mode control (다중 슬라이딩 모드 제어 방법의 성능 평가)

  • Chang, Wook;Joo, Jin-Man;Park, Jin-Bae
    • Proceedings of the KIEE Conference
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    • pp.658-660
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    • 1995
  • This paper presents a performance analysis of the multiple sliding mode control for SISO system. The multiple sliding mode control technique uses sliding surfaces for each state. The performance analysis is done by comparison between the multiple sliding mode control and the sliding mode control. Overall performance of the multiple sliding mode control is improved over that of the sliding mode control. Results of numerical simulations are presented.

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Dynamic Analysis of Machine Tool Structure by Mode Synthesis Method (모드합성법을 이용한 공작기계구조물의 동적 거동 해석)

  • 이영우;성활경
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.261-265
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    • 2002
  • In the machining tool avoid vibration problem have an effect on high precision as well as statical and thermal characteristics. Therefore overcome this problem is essential to advance of machine tool and machining skill. Even though vibration arises owing to a variety of causes, in this paper vibration analysis of column as a major part of machine tool structures is presented. At this procedure vibration analysis applied to mode synthesis method using a attachment mode .

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A Study on Changes in Body Surface Temperature and Thermal Effect According to Ultrasound Mode (초음파 진단모드에 따른 체표면 온도변화와 열효과에 관한 고찰)

  • Yang, Sung-Hee;Lee, Jin-Soo
    • Journal of radiological science and technology
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    • v.40 no.2
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    • pp.213-218
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    • 2017
  • Recently, as the number of high-risk pregnancies increases, the use of new techniques such as Doppler, which have higher acoustic power than in the past, has been increasingly used in prenatal diagnosis and guidelines have been set up by various organizations to prevent excessive exposure. Therefore, in this study, we tried to investigate the temperature change of the body surface for each test mode according to the long time ultrasound examination and to examine the exposure time which is not influenced by the thermal effect. B mode, C mode, and PD mode according to time, and the temperature difference between exposed and unexposed sites were compared. As a result, the B mode showed a significant difference in the temperature change from 10 minutes, 50 minutes after exposed, 20 minutes from the C mode, and 30 minutes from the PD mode (p<0.01). In all three modes, the temperature difference was different (p<0.000), and PD mode was the most sensitive to temperature change. Also, it was found that the temperature rise time was shortened with the increase of the ultrasonic exposure time. Therefore, it is recommended that ultrasonography to observe the embryo or fetus should be used only for diagnostic purposes, avoiding excessive test time.

An Experimental Study on the Fatigue Crack Propagation Behavior in CTS Specimen under Mode II Loading (모드 II 하중을 받는 CTS 시험편의 피로균열 전파거동에 관한 실험적 연구)

  • Song, Sam-Hong;Lee, Jeong-Moo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.7
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    • pp.1217-1226
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    • 2003
  • The purpose of this paper is to investigate fatigue crack behavior under shear(Mode II) loading. Various specimens and devices have been used in order to produce Mode II loading in fatigue experiments for shear crack propagation. But, there is not sufficient comparisons of experimental results between Mode II and others loading modes, because of characteristics of applied loads and specimens. So, compact tension shear(CTS) specimens were used in this paper to investigate the propagation behavior of Mode II by comparing the experimental results between loading modes. We firstly observed the characteristics which was showed in Mode II experiment using CTS specimens. The experimental results under Mode II loading were compared with fatigue crack behavior under Mode I and Mixed-mode I+II loading. The characteristics for initiation and propagation behavior under Mode II loading was investigated by such comparisons.

Fast Inter Mode Decision Algorithm Based on Macroblock Tracking in H.264/AVC Video

  • Kim, Byung-Gyu;Kim, Jong-Ho;Cho, Chang-Sik
    • ETRI Journal
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    • v.29 no.6
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    • pp.736-744
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    • 2007
  • We propose a fast macroblock (MB) mode prediction and decision algorithm based on temporal correlation for P-slices in the H.264/AVC video standard. There are eight block types for temporal decorrelation, including SKIP mode based on rate-distortion (RD) optimization. This scheme gives rise to exhaustive computations (search) in the coding procedure. To overcome this problem, a thresholding method for fast inter mode decision using a MB tracking scheme to find the most correlated block and RD cost of the correlated block is suggested for early stop of the inter mode determination. We propose a two-step inter mode candidate selection method using statistical analysis. In the first step, a mode is selected based on the mode information of the co-located MB from the previous frame. Then, an adaptive thresholding scheme is applied using the RD cost of the most correlated MB. Secondly, additional candidate modes are considered to determine the best mode of the initial candidate modes that does not satisfy the designed thresholding rule. Comparative analysis shows that a speed-up factor of up to 70.59% is obtained when compared with the full mode search method with a negligible bit increment and a minimal loss of image quality.

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Control System of 600kW EBOP for Molten Carbonate Fuel Cell Generation System (600kW급 용융탄산염 연료전지 발전시스템용 EBOP 제어시스템)

  • Hwang, Tai-Sik;Joung, Woo-Taek;Yang, Byung-Hoon;Kim, Kwang-Seob;Kwon, Byung-Ki;Choi, Chang-Ho
    • Proceedings of the KIPE Conference
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    • pp.18-20
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    • 2008
  • An electrical balance of plant(EBOP) of a 600kW molten carbonate fuelcell (MCFC) has to transit from grid-connected(GC) mode to grid-independent(GI) mode when a grid is in a fault conditions. A minimum transition time is limited by four cycle for a 600kW MCFC to ride through a grid fault. In this paper, we propose a control algorithm of a 600kW EBOP for a MCFC system. The EBOP has three operation modes, i.e., GC mode, GI mode, and grid-synchronized(GS) mode. The EBOP controls output currents in a GC mode and regulates output voltages in GI or GS mode. GS mode is defined as an interface between GC mode and GI mode to make a mode transition smooth, i.e., limitation of inrush currents, regulation of output voltages within ANSI standard. Simulations and experiments carried out to verify the effectiveness of the proposed control algorithm.

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A Performance Comparison of the Partial Linearization Algorithm for the Multi-Mode Variable Demand Traffic Assignment Problem (다수단 가변수요 통행배정문제를 위한 부분선형화 알고리즘의 성능비교)

  • Park, Taehyung;Lee, Sangkeon
    • Journal of Korean Institute of Industrial Engineers
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    • v.39 no.4
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    • pp.253-259
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    • 2013
  • Investment scenarios in the transportation network design problem usually contain installation or expansion of multi-mode transportation links. When one applies the mode choice analysis and traffic assignment sequentially for each investment scenario, it is possible that the travel impedance used in the mode choice analysis is different from the user equilibrium cost of the traffic assignment step. Therefore, to estimate the travel impedance and mode choice accurately, one needs to develop a combined model for the mode choice and traffic assignment. In this paper, we derive the inverse demand and the excess demand functions for the multi-mode multinomial logit mode choice function and develop a combined model for the multi-mode variable demand traffic assignment problem. Using data from the regional O/D and network data provided by the KTDB, we compared the performance of the partial linearization algorithm with the Frank-Wolfe algorithm applied to the excess demand model and with the sequential heuristic procedures.

Effects of Fine Contents on the Fracture Characteristics of Frozen Sand (세립분 함유량이 동결 사질토의 파괴특성에 미치는 영향)

  • Hwang, Bumsik;Cho, Wanjei
    • Journal of the Korean Geotechnical Society
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    • v.36 no.3
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    • pp.25-36
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    • 2020
  • In this research, three-point bending tests were performed using a rectangular frozen specimen with various fine contents and notch offset distance from the center of the specimen to investigate the fracture characteristic of the frozen sand. Based on the test results, mode I fracture toughness was calculated, and mixed-mode (mode I + II) fracture characteristics were investigated using the fracture energy which was calculated until the maximum point of the load-displacement curve. As the fine contents increase, the peak load and mode I fracture toughness increase until 10% fine contents. Furthermore, as the notch offset distance increases, the fracture energy required for crack start also increases due to the increase in mode II load at the crack tip.

Design of a DC Motor Current Controller Using a Sliding Mode Disturbance Observer and Controller (슬라이딩 모드 외란 관측기와 제어기를 이용한 DC 모터 전류 제어기 설계)

  • Kim, In Hyuk;Son, Young Ik
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.6
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    • pp.417-423
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    • 2016
  • Using a sliding mode controller and observer techniques, this paper presents a robust current controller for a DC motor in the presence of parametric uncertainties. One of the most important issues in the practical application of sliding mode schemes is the chattering phenomenon caused by switching actions. This paper presents a novel sliding mode controller that incorporates an integral control with a sliding mode disturbance observer to attenuate the chattering by reducing the controller/observer switching gains. The proposed sliding mode disturbance observer is designed to estimate a relatively slow varying signal in the equivalent lumped disturbance owing to system uncertainties. Combining the estimated uncertainty with the sliding mode control input, the proposed controller can achieve the control objective by using the relatively low gain of the controller. The proposed disturbance observer does not include the switching control input of the baseline sliding mode controller to reduce the observer switching gain. In the proposed approach, the integral sliding mode control is used to improve the steady state control performance. Comparative computer simulations are carried out to demonstrate the performance of the proposed method. Through the simulation results, the proposed controller realizes the robust performance with reduced current ripples.

Delamination identification of laminated composite plates using measured mode shapes

  • Xu, Yongfeng;Chen, Da-Ming;Zhu, Weidong;Li, Guoyi;Chattopadhyay, Aditi
    • Smart Structures and Systems
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    • v.23 no.2
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    • pp.195-205
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    • 2019
  • An accurate non-model-based method for delamination identification of laminated composite plates is proposed in this work. A weighted mode shape damage index is formulated using squared weighted difference between a measured mode shape of a composite plate with delamination and one from a polynomial that fits the measured mode shape of the composite plate with a proper order. Weighted mode shape damage indices associated with at least two measured mode shapes of the same mode are synthesized to formulate a synthetic mode shape damage index to exclude some false positive identification results due to measurement noise and error. An auxiliary mode shape damage index is proposed to further assist delamination identification, by which some false negative identification results can be excluded and edges of a delamination area can be accurately and completely identified. Both numerical and experimental examples are presented to investigate effectiveness of the proposed method, and it is shown that edges of a delamination area in composite plates can be accurately and completely identified when measured mode shapes are contaminated by measurement noise and error. In the experimental example, identification results of a composite plate with delamination from the proposed method are validated by its C-scan image.