• 한국소음진동공학회논문집
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• 제15권8호
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• pp.988-995
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• 2005

Vibration has been severly increased at the branch pipe of main steam header since the commercial operation of nuclear power plant. Intense broad band disturbance flow at the discontinuous region such as elbow, valve, and header generates the acoustical pulsation which is propagated through the piping system. The pulsation becomes the source of low frequency vibration at piping system. If it coincide with natural frequency of the pipe system, excessive vibration is made. High level vibration due to the pressure pulsation related to high dynamic stress, and ultimately, to failure probability affects fatally the reliability and confidence of plant piping system. This paper discusses vibration effect for the branch pipe system due to acoustical pulsations by broad band disturbance flow at the large main steam header in 700 MW nuclear power plant. The exciting sources and response of the piping system are investigated by using on-site measurements and analytical approaches. It is identified that excessive vibration is caused by acoustical pulsations of 1.3 Hz, 4.4 Hz and 6.6 Hz transmitted from main steam balance header, which are coincided with fundamental natural frequencies of the piping structure. The energy absorbing restraints with additional stiffness and damping factor were installed to reduce excessive vibration.

• 한국초전도ㆍ저온공학회논문지
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• 제3권1호
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• pp.11-15
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• 2001

Stability of a Bi-2223/Ag tape was studied by using a numerical model considering the temperature distribution of cross-sectional area. The dynamic evolution of normal zone of a HTS tape can be shown by the developed two-dimensional Program using finite difference method. Two kinds of analyses are compared to quantify the critical disturbance energy for quenching HTS tapes. One is the length-thickness(x-r) side and the other is the length-width(x-z) side. For each case. the governing energy balance equations and corresponding boundary conditions are formulated. The results of analyses shows that the critical disturbance energies for each cases seem to be very close for considered Bi-2223/Ag tape .

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.121-122
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• 2002

When a power system experiences a serious disturbance on insufficient power, the system frequency may drop. For system frequency will be maintain standard value, under_frequency relay will reconstruct balance of power and load by load shedding. Currently load shedding scheme is due to establishment plan by fixed scenario. Where compare current scheme with past scheme, system frequency should be recovered by load shedding using rate of frequency decline. This paper suggests the dynamic load shedding scheme by using the rate of change of frequency when The Korea Electric power system is happened the large disturbance.

• Journal of Acupuncture Research
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• 제17권3호
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• pp.75-86
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• 2000

Objectives : This study is to applied effectively to the acupuncture treatment for disorders following whiplash injuries. Methods : This study suggests five various ways and principtes of treating disorders following whiplash injuries by means of acupuncture. First principle is that acupuncture treatment is carried out on acupoint far from cervical spine at acute stage, on the other hand, Extraordinary Vessel and other acupuncture treatment such as five element acupuncture treatment is applied at chronic stage in order to control balance disoders due to cervical pathology. Second is acupuncture treatment will be performed in group of three part of Meridian System-Yangmyung, Taeyang, Soyang-according to cervical kinetic, its characteristic and location of pain. Third is acupuncture treatment could be performed on basis of theory of Eohyel-disorders and disturbance of blood circulation. Fourth is to decrease tension of SCM muscle, because disorders following whiplash injuries has much association to injury of CM muscle and is simillar to tension syndroms of SCM muscle. fifth is taping therapy could control and decrease disorders following whiplash injuries based on spiral balance taping theory. Conclusions : These results suggest that acupuncture treatment for disorders following whiplash injuries will significally decrease pain and control syndrom caused by cervical disorder.

• 제어로봇시스템학회논문지
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• 제21권7호
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• pp.677-683
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• 2015

This paper proposes a helicopter direction adjustment system using barycenter shift. Most conventional methods for direction adjustment of uniaxial helicopters rely on the angle of inclination of the main rotor. However, the inherent burden of the bearing of the main rotor and serious abrasion of the helicopter using the above methods may results in loss of balance. To decrease abrasion and enhance the barycenter stability, the proposed method was used to shift the barycenter of the helicopter instead of the main rotor for direction adjustment. We set a biaxial ARM on a uniaxial helicopter to adjust the direction of ARM pointing as well as to realize stable direction control when the helicopter loses its balance. The method may enhance the landing safety of helicopters in emergencies. Uniaxial helicopters can be controlled under any environment by adjusting the motor parameters of the ARM which is dependent on the center of mass using neural network. The experiment results show that the helicopter can return to the starting position quickly under the external disturbance.

• 대한한방내과학회지
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• 제39권4호
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• pp.802-813
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• 2018

This case report describes a patient with olivopontocerebellar atrophy accompanied by sleep disorder and gait disturbance whose condition was improved by treatment with Korean medicine. The 61-year-old woman, who was diagnosed with olivopontocerebellar atrophy (Multiple Systemic Atrophy-Cerebellum), was admitted to hospital twice and treated with Korean medicine (acupuncture and herbal medicine) and rehabilitation. The Korean medicine was Gwibiondam-tang-gami and Jaeumgeonbi-tang-gami. Clinical symptoms were assessed by the Modified Bathel index, functional independent measurement, Berg balance scale, and Unified Multiple System Atrophy rating scale. A brain MRI at the one-year follow up after onset showed similar progress but clinical symptoms were improved after treatment, and the evaluation index score increased. Multiple system atrophy, a type of degenerative neurological disease, has no targeted treatment. In this situation, although this report describes a single case, Korean medicine treatment could provide a meaningful improvement in the sleep disturbance and gait disorder symptoms of patients with olivopontocerebellar atrophy.

• 대한한방내과학회지
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• 제41권5호
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• pp.821-829
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• 2020

This case report describes the effects of Korean Medicine for the gait disturbance of Multiple System Atrophy (MSA). Korean Medicine that included chuna manual therapy, pharmaco-acupuncture, herbal medicine, acupuncture, electro-acupuncture, and moxibustion was administered for 23 days. During the hospitalization period, evaluations were performed using the Unified Multiple System Atrophy Rating Scale (UMSARS), Berg Balance Scale (BBS), and 20 m Round Timed Walking Test on day 1, day 15, and day 23. The UMSARS Part I score decreased from 11 to 5, Part II score from 11 to 9, and total score from 22 to 14, and the BBS score increased from 36 to 48. The 20 m Round Timed Walking Test score also improved. The width of the gait decreased from 65 to 40 cm, and the number of staggering incidents decreased from 6 times to 2 times. The findings of this case study suggest that Korean Medicine, including Chuna manual therapy, has potential benefits in MSA patients with gait disturbance.

• 한국전문물리치료학회지
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• 제9권3호
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• pp.77-91
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• 2002

Asymmetrical stance posture, balance, and gait disturbance are common problems in hemiplegic patients. Posterior leaf springs (PLS) are frequently prescribed to correct these problems. Recently, anterior leaf springs (ALS) have also been prescribed, but only limited studies have been performed to investigate the effects of ALS. The purpose of this study was to compare the effects of three conditions, i.e., wearing an ALS, wearing a PLS, and not wearing an AFO (ankle foot orthosis),: on 1) the distribution of weight bearing on the affected side, 2) standing balance, and 3) the gait patterns of hemiplegic patients. Eleven hemiplegic patients (10 men and 1 woman) participated in this study. The data were analyzed by the Friedman test. The results were as follows: 1) More weight bearing on the affected leg was observed in the ALS and PLS conditions than in the condition without an AFO. No significant difference between the ALS and PLS conditions was found. 2) There were statistically significant differences in the composite equilibrium scores (CES) among the three conditions. The CES in the PLS condition was significantly higher than in the ALS condition or the condition without an AFO. 3) Gait patterns improved significantly in the ALS and PLS conditions. No statistically significant difference between the ALS and PLS conditions was found. These results suggest that both ALS and PLS effectively improve the distribution of weight bearing on the affected side, standing balance, and gait patterns of hemiplegic patients. Further study using three-dimensional kinematic analysis and dynamic electromyography is needed to support these findings.

• 농약과학회지
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• 제19권1호
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• pp.1-4
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• 2015

잔류성 유기오염물질인 과불화합물 중 perfluorooctanesufonic acid (PFOS)와 perfluorooctanoic acid (PFOA)의 잔류분석은 환경부 "잔류성 유기오염물질 공정시험기준"에 따라 hydrophilic-lipophilic balance (HLB) solid phase extraction (SPE) 전처리 후 LC-$MS^n$를 이용해 정량 분석하고 있다. 본 연구에서는 환경부 설정 공정시험법에 따라 농업용수 전처리 후, 시험법에서 제거하지 못한 미지의 불순물을 Envi-Carb$^{TM}$을 통해 회수율에 영향을 주지 않고 손쉽게 제거하였다. 또한, 과불화합물 분석에 사용되는 LC-$MS^n$ 중 quadrupole-time-of-flight mass spectrometry (qTOFMS)에서 측정된 PFCs의 정량한계를 평가한 결과, 시험에 사용된 장비간 정량한계 편차가 크게 관찰되었으나, 시험대상 장비 모두 농업용수 중 ng/L 수준으로 잔류하는 과불화합물의 정밀 잔류분석에 사용가능 한 것으로 확인되었다.

• Journal of Mechanical Science and Technology
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• 제16권1호
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• pp.75-82
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• 2002

A simultaneous optimal design problem of structural and control systems is discussed by taking a 3-D truss structure as an object. We use descriptor forms for a controlled object and a generalized plant because the structural parameters appear naturally in these forms. We consider a minimum weight design problem for structural system and disturbance suppression problem for the control system. The structural objective function is the structural weight and the control objective function is $H_{\infty}$ norm from the disturbance input to the controlled output in the closed-loop system. The design variables are cross sectional areas of the truss members. The conditions for the existence of controller are expressed in terms of linear matrix inequalities (LMI) By minimizing the linear sum of the normalized structural objective function and control objective function, it is possible to make optimal design by which the balance of the structural weight and the control performance is taken. We showed in this paper the validity of simultaneous optimal design of structural and control systems.