• Title/Summary/Keyword: DAMP

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Effects of atmospheric turbulence on the laser cross-beam velocimeter (레이저 크로스빔 속도계에 대한 대기교란 효과)

  • sung pyung-shik
    • Journal of the Korea Computer Industry Society
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    • v.6 no.2
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    • pp.259-264
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    • 2005
  • This paper have derived an expression(the fringe modle is used) for the photocurrelation-correlation function for a cross-beam laser velocimeter, taking into account the effects of atmospheric turbulence on the amplitude and phase of the incident beams. the result, as long as the atmospheric disturbances do not greatly damp out sinusoidal variations of the photocurrent-correlation function in the time it takes a particle to travel the fringe-separation distance, the disturbances do not hinder the determination of the velocity of the partides from the correlation funtion.(the scattering particles are assumed to have a well-defined V).

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One case treated bladder cancer with Immunity-herbal acupuncture (면역약침(免疫藥鍼)을 이용(利用)한 방광암(膀胱癌) 치험(治驗) 1례(例))

  • Kim, Dong-Suk;Oh, Sung-Jong;Lee, Sang-Ryong
    • Journal of Pharmacopuncture
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    • v.5 no.1 s.8
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    • pp.153-157
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    • 2002
  • In oriental medicine bladder cancer had been called '溺血(Hematuria)', 血淋(Blood Stranguria)', 濕熱河注(Downward Flow of Damp-heat)' and so on. The symptoms are Hematuria, Oliguria, Lower abdomen pain, febrile sensation and Anemia etc. These are similar to the symptoms of bladder cancer by modem medicine. I have experienced a bladder cancer patient who was diagnosed as stage Ⅲ. She has been treated bladder cancer with Immunity herbal acupuncture and Her clinical and objective symptoms have been better. Therefore I report this results.

The PI control of the Voltage Bus Conditioner for the improvement of the Power Quality in the DC Power Distribution System with multiple parallel loads (다중 병렬 부하를 가지는 DC 배전 시스템에서의 전력 품질 향상을 위한 Voltage Bus Conditioner의 PI 제어)

  • Lee, Byung-Hun;Woo, Hyun-Min;La, Jae-Du;Shin, Jae-Hwa;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1234-1235
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    • 2011
  • A DC Power Distribution Systems(DC PDS) are widely used in telecommunication system, electric vehicle, aircraft, military system, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple loads such as pulsed power load, motor drive system, and constant power loads. To damp the transients of the DC bus voltage, the Voltage Bus Conditioner(VBC) with the PI compensator is used. In this paper, the validity of the proposed VBC system is verified by PSIM simulation package.

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A case study of patient with Ischemic Cerebrovascular Accident at Puerperium (산욕기에 발생한 뇌경색증 1예의 임상 보고)

  • Jung, Ho-Joon;Chang, Young-Chul;Kwon, Do-Ick;Ahn, Jong-Pil
    • The Journal of Internal Korean Medicine
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    • v.21 no.5
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    • pp.883-887
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    • 2000
  • A clinical study was carried out 1 case of ischemic cerebrovascular accident which occurred at puerperium in a 27 year-old woman followed by vaginal delivery The results were as follows: 1. In the clinical view, it was thought that the cause of this case is intracranial venous thrombus, because the symptom-headache, foaming at the mouse, acromyotonia, hemiparesis- occurred in the postpartum and functional outcome is good. 2. In this case, the patient's functional system of spleen-stomach is usually weak, and due to delivery the functional system of spleen-stomach is more insufficient. so it can not control damp-phlegm(濕痰). In addition, vital energy of liver stagnate.

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A New Design of Fuzzy controller for HVDC system with the aid of GAs (HVDC 시스템에 대한 유전자 알고리즘을 사용한 새로운 퍼지 제어기의 설계)

  • Wang Zhong-Xian;Yang Jueng-Je;Rho Seok-Beom;Ahn Tae-Chon
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.3
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    • pp.221-226
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    • 2006
  • In this paper, we study an approach to design a Fuzzy PI controller in HVDC(High Voltage Direct Current) system. In the rectifier of traditional HVDC system, turning on, turning off, triggering and protections of thyristors have lots of problems that can make the dynamic instability and cannot damp the dynamic disturbance efficiently. In order to solve the above problems, we adapt Fuzzy PI controller for the fire angle control of rectifier. The performance of the Fuzzy PI controller is sensitive to the variety of scaling factors. The design procedure dwells on the use of evolutionary computing(Genetic Algorithms, GAs). Then we can obtain factors of the Fuzzy PI controller by Genetic Algorithms. A comparative study has been performed between Fuzzy PI controller and traditional PI controller, to prove the superiority of the proposed scheme.

Saenggangeonbi-tang's Effect on Alcoholic Liver Cirrhosis - 1 Case (생간건비탕가감을 투여한 알콜성 간경변증 환자 치험 1례)

  • 이은;고흥
    • The Journal of Korean Medicine
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    • v.21 no.3
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    • pp.213-219
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    • 2000
  • We treated a 53 year-old male patient. He had alcoholic liver cirrhosis and diabetes. The main symptoms were fatigue, ascites, edema, anorexia, indigestion, constipation, and abdominal pain. We diagnosed him as 'the retention of pathogenic damp-heat in the liver and gall bladder’ and adminstered Saenggangeonbi-tang three times a day. We observed clinical symptoms, liver function test(AST, ALT, ${\gamma}-GT$, ALP, total bilirubin), nutritional state(total protein, albumin) and capillary blood glucose. After treatment, all the main symptoms disappeared and the patient's nutritional state has improved. Child's grade using the improvement index in liver cirrhosis has changed from B to A. Although the very mechanism of Saenggangeonbi-tang was not proven, we could suggest that Saenggangeonbi-tang is not toxic to the liver and has a good effect on alcoholic liver cirrhosis with diabetes mellitus.

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A Variable Hysteresis Control for a DC Bus Conditioner (DC Bus Conditioner을 위한 카변히스테리시스제어)

  • La, Jae-Du;Han, Moon-Seob
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.472-475
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    • 2008
  • A DC distributed power system(DPS) has many loads with varied functions. In particular, there may be large pulsed toads with short duty ratio, which can affect the normal operation of other loads. In this paper, a bi-directional converts with inductive storage is used as a DC bus conditioner to damp voltage transients on the bus. In addition, the constant frequency hysteresis control technique for a DC bus conditioner is presented. A simple and fast prediction of the hysteresis band-width is implemented by the phase-lock loop control, keeping constant switching frequency. This technique offers the excellent dynamic response in load or parameter variation. The control performance is illustrated by simulated results with the SABER package. The proposed hysteresis control results in the shortest and the smallest excursions.

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Parameter Selection Method for Power System Stabilizer of a Power Plant based on Hybrid System Modeling (하이브리드시스템 모델링 기반 발전기 전력시스템 안정화장치 정수선정 기법)

  • Baek, Seung-Mook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.7
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    • pp.883-888
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    • 2014
  • The paper describes the parameter tuning of power system stabilizer (PSS) for a power plant based on hybrid system modeling. The existing tuning method based on bode plot and root locus is well applied to keep power system stable. However, due to linearization of power system and an assumption that the parameter ratio of the lead-lag compensator in PSS is fixed, the results cannot guarantee the optimal performances to damp out low-frequency oscillation. Therefore, in this paper, hybrid system modeling, which has a DAIS (differential-algebraic-impusive-switched) structure, is applied to conduct nonlinear modeling for power system and find optimal parameter set of the PSS. The performances of the proposed method are carried out by time domain simulation with a single machine connected to infinite bus (SMIB) system.

Identification and Damping of Resonances in Inverter-based Microgrids

  • Afrasiabi, Morteza;Rokrok, Esmaeel
    • Journal of Power Electronics
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    • v.18 no.4
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    • pp.1235-1244
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    • 2018
  • The application of shunt capacitor banks and underground cables typically induces resonance in power distribution systems. In this study, the propagation of resonance in a microgrid (MG) with inverter-based distributed generators (IBDGs) is investigated. If resonances are not properly damped, then the output current of the inverters may experience distortion via resonance propagation due to the adverse effect of resonances on MG power quality. This study presents a conceptual method for identifying resonances and related issues in multi-inverter systems. For this purpose, existing resonances are identified using modal impedance analysis. However, some resonances may be undetectable when this method is used. Thus, the resonances are investigated using the proposed method based on the frequency response of a closed-loop MG equivalent circuit. After analyzing resonance propagation in the MG, an effective virtual impedance damping method is used in the IBDG control system to damp the resonances. Results demonstrate the effectiveness of the proposed method in compensating for existing resonances.

Design of a Low-order Pole Placement Power System Stabilizer Using Simultaneous Stabilization (동시안정화를 이용한 저차원 극배치 전력계통안정화장치 설계)

  • Kim, Seog-Joo;Lee, Jong-Moo;Kwon, Soon-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.10
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    • pp.1708-1712
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    • 2008
  • This paper describes a linear matrix inequality (LMI) approach to the design of robust low-order power system stabilizers (PSSs), which are used to damp out local-mode oscillations of synchronous generators. The performance of a PSS is expressed as the location of the closed-loop poles, and a single fixed-gain pole-placement controller is synthesized for a wide range of operating conditions. The synthesis results in simultaneous regional pole-placement stabilization. and is formulated as an LMI feasibility problem with a rank condition. A penalty method is applied to solve the rank-constrained LMI problem. Numerical experiments with a single-machine connected to an infinite bus system were performed to demonstrate the proposed method.