• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.203-205
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.387-390
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit Incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Earthquakes and Structures
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• 제25권6호
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• pp.417-427
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• 2023

If the center of mass and center of stiffness or strength of a structure plan do not coincide, the structure is considered asymmetric. During an earthquake, in addition to lateral vibration, the structure experiences torsional vibration as well. Lateraltorsional coupling in asymmetric structures in the plan will increase lateral displacement at the ends of the structure plan and, as a result, uneven deformation demand in seismically resistant frames. The demand for displacement in resistant frames depends on the magnitude of transitional displacement to rotational displacement in the plan and the correlation between these two. With regard to the inability to eliminate the asymmetrical condition due to various reasons, such as architectural issues, this study has attempted to use supplemental viscous dampers to decrease the correlation between lateral and torsional acceleration or displacement in the plan. This results in an almost even demand for lateral deformation and acceleration of seismic resistant frames. On this basis, using the concept of Torsional Balance, adequate distribution of viscous dampers for the decrease of this correlation was determined by transferring the "Empirical Center of Balance" (ECB) to the geometrical center of the structure plan and thus obtaining an equal mean square value of displacement and acceleration of the plan edges. This study analyzed stiff and flexible torsional structures with one-way and two-way mass asymmetry in the Opensees software. By implementing the Particle Swarm Optimization (PSO) algorithm, the optimum formation of dampers for controlling lateral displacement and acceleration is determined. The results indicate that with the appropriate distribution of viscous dampers, not only does the lateral displacement and acceleration of structure edges decrease but the lateral displacement or acceleration of the structure edges also become equal. It is also observed that the optimized center of viscous dampers for control of displacement and acceleration of structure depends on the amount of mass eccentricity, the ratio of uncoupled torsional-to-lateral frequency, and the amount of supplemental damping ratio. Accordingly, distributions of viscous dampers in the structure plan are presented to control the structure's torsion based on the parameters mentioned.

• 대한감각통합치료학회지
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• 제16권1호
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• pp.14-24
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• 2018

목적 : 본 연구는 Attention Deficit Hyperactivity Disorder(ADHD) 아동에게 시행한 상호작용식 메트로놈(Interactive Metronome; IM) 중재가 자세조절과 글씨쓰기에 미치는 영향에 대해 알아보고자 하였다. 연구방법 : 본 연구는 ADHD로 진단받은 초등학교 3학년 아동 1명을 대상으로 시행하였다. 개별실험 연구방법 중에서 ABA 설계를 사용하였고, 총 30회기로 매주 3회기 씩 총 10주 진행하였다. 기초선과 재기초선 기간에는 글씨쓰기 과제의 측정만 실시하였고, 중재기 동안에 IM 훈련을 40~50분간 실시하고 난 후에 글씨쓰기의 명료도와 속도를 평가하였다. 기초선을 시작하기 전과 재기초선이 끝나고 한 달 이내에 Clinical Observation of Motor and Postural Skills(COMPS)를 실시하여 자세조절의 변화를 알아보았다. 결과 : IM 중재를 시행한 후 대상자의 자세조절 변화는 하위항목 중 슬로모션, 손가락-코 운동, 비대칭 경반사의 점수가 향상되었고, 글씨쓰기 명료도와 속도는 중재 기간 동안 상승하는 경향을 보였으나 유의하게 변화되지 않았다. 결론 : 본 연구를 통해 ADHD 아동을 대상으로 한 IM 훈련의 중재가 자세조절과 글씨쓰기 수행능력을 향상시키는데 긍정적인 효과를 확인할 수 있었고, 향후 연구에 새로운 방향에 접근할 수 있는 기회를 제공하였다는 근거로 사용될 수 있을 것이다.

• 대한전자공학회논문지TC
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• 제38권3호
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• pp.35-43
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• 2001

반사형(혹은 역방향) 결합선로에서 원하는 결합도를 가질 수 있도록 모드 특성임피던스를 합성하는 방법을 새로이 제안하였다. 결합도를 나타내는 일차 비선형 미분방정식의 해 혹은 Riccati 해가 갖는 반복되는 lobe들의 최소점, 즉 null점들을 최적 섭동시키므로서 최적 합성이 이루어진다. 이 과정을 위해 일차원 배열 안테나의 공간인자 패턴 제어를 통한 일차원 비선형 소스 분포함수 합성법을 근간으로 하였으며, 기존의 우함수형 분포함수 합성을 기함수형까지 확장 적용할 수 있는 방법을 제시하였다. 그 결과로서 도출된 모드 특성임피던스들은 연속적이고 비선형적인 프로필을 가지게 된다. 합성된 우함수형 및 기함수형 분포함수에 대응되는, 비대칭형 및 대칭형 결합기들을 비교 분석하였으며, 기존의 설계방법에 비해 일반적이고 간단함을 보였다.

• 생물정신의학
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• 제2권1호
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• pp.107-114
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• 1995

This study was to investigate the anatomical evidence of anxiety. MRI was used to study 11 patients with panic disorder and 15 patients with complex partial seizure, and 21 controls. The regions of interest in the MRI were measured with computer-assisted planimetry using the AutoCad and digitizer. The following results were obtained ; 1) The mean age was 49.7(12.4) years in patients with panic disorder and 30.1(7.5) years in patients with complex partial seizure. 2) There were na signi ficant differences between 3 groups in the values of cerebral area, temporal lobe, caudate nucleus, hippocampus, parahippocampus, amygdala, third ventricle and VBR. The right parahippocampal region which attracted most attention in neurobiological studies regarding anxiety, tended to be larger in both study groups compared to the control group, but with no statistical significance. 3) There was lett-right reversal of temporal lobes in both study groups. And these are mainly due to asymmetrical increase in area of the temporal lobe on right side. These results suggest that temporal lobe, especially right temporal, is the anatomical correspondence of anxiety and functional activation of temporo-limbic system may be accompanied by the structural change of temporal lobe.

• 전자공학회논문지
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• 제53권4호
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• pp.106-114
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• 2016

본 논문에서는 VP9 디코더에 대한 행렬 기반의 정수형 역변환 구조를 제안한다. 제안하는 구조는 DCT(Discreste Cosine Transform), ADST(Asymmetric Discrete Sine Transform) 그리고 WHT(Walsh-Hadamard Transform)에 대한 알고리즘을 공유하며 버터플라이구조보다 하드웨어 리소스를 줄이고 제어하기 쉬운 하드웨어 구조이다. VP9 구글 모델 내 정수형 역변환은 버터플라이구조 기반의 정수형 역변환 구조를 가진다. 일반적인 버터플라이구조와는 달리 구글모델 내 정수형 역변환은 각 단계마다 라운드 쉬프트 연산기를 가지며, 비대칭 구조의 사인 변환을 포함한다. 따라서 제안하는 구조는 모든 역변환 모드에 대해 행렬계수 값을 근사하고, 이 계수 값을 이용하여 행렬연산 방식을 사용한다. 본 논문의 기술을 사용하면 역변환 알고리즘에 대한 모드별 동작 공유 및 버터플라이구조에 비해 곱셈기 수를 2배가량 감소시킬 수 있다. 그래서 하드웨어 리소스를 효율적으로 관리가 가능해진다.

• 전력전자학회논문지
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• 제5권4호
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• pp.309-317
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• 2000

이 논문은 4상 6극 SRM의 최대토크/효율 및 최소토크맥동 운전을 위한 적정 전압과 스위칭각에 관한 연구이다. SRM은 비선형적인 특성이강하여 해석적인 방법으로 특성을 고찰하거나 속도/토크 제어가 어려운 단점이 있다. 이 논문에서는 최대토크/효율 및 최소토크맥동의 운전이 가능한 최적의 스위칭각과 전압을 SIMULINKK를 이용하여 구하였다. 시뮬레이션 결과 최대토크운전에서는 속도는 스위칭각에 의존되고, 토크는 전압에 의존됨을 알 수 있었다. 뿐 만 아니라 최대효율, 최소토크리플운전에서는 전압보디는 속도와 스위칭각에 의해서 최대효율과 최소토크 리플이 발생되는 것을 알 수 있었다. 시뮬레이션에 의해서 구해진 최적각들을 ROM 데이터형식으로 참조 테이블을 만들어 마이크로 프로세서를 이용하여 구동하여 최대토크/효율, 최소토크리플 운전의 타당성을 보였다.

• 대한인간공학회지
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• 제35권6호
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• pp.493-501
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• 2016

Objective: This study analyzes the effect of angle conditions of rehabilitation equipment used for supporting hemiplegic patients on their rehabilitation training for standing action. The study was performed by adjusting the rear angle of seat inclination through a motion analysis. Background: Owing to a loss of muscle rigidity and degradation of muscle control ability, hemiplegic stroke patients suffer from asymmetrical posture, abnormal body balance, and degraded balance abilities due to poor weight-shifting capacity. The ability to shift and maintain one's weight is extremely essential for mobility, which plays an important role in our daily life. Thus, to improve patients' ability to maintain weight evenly and move normally, they need to undergo orthostatic and ambulatory training. Method: Using a motion analysis system, knee movements on both hemiplegic side and non-hemiplegic side were measured and analyzed in five angles ($0^{\circ}$, $10^{\circ}$, $30^{\circ}$, $50^{\circ}$, $70^{\circ}$) while supported by the sit-to-stand rehabilitation equipment. Results: The knee movements on both sides increased as the angle increased in angle support interval to support a hemiplegic patient's standing up position. In standing up interval, a hemiplegic patient's knee movement deviations on both sides decreased, and the movement differences between hemiplegic and non-hemiplegic legs also decreased as the angle increased. Conclusion: The results of this study showed that the rehabilitation effectiveness increases as the angle increases, leading to a balanced standing posture through the decrease of movement difference between hemiplegic and non-hemiplegic sides and an improved standing up ability through the increase of knee movement on both sides. However, angles higher than $50^{\circ}$ didn't provide a significant effect. Therefore, a support angle under $50^{\circ}$ was proposed in this study. Application: The results of this study are expected to be applicable to the design of sit-to-stand support equipment to improve the effectiveness of the rehabilitation process of hemiplegic patients.

• 한국산업보건학회지
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• 제8권1호
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• pp.1-23
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• 1998

Work-related Low Back Pain(LBP) is one of tile most important Issues in the field of industrial safety and health. Particularly, manual lifting is known as a major cause of work-related LBP and impairment. Total number of 163 manual lifting tasks in motor assembly processes were investigated. The 1981 and the 1994 equations developed by National Institute for Occupational Safety and Health(NIOSH) were applied to evaluate potential hazards of lifting-related LBP. Comparisons between the 19R I and 1994 NIOSH criteria were made. The relationships between the NIOSH criteria and lifting-related LBP were also analyzed. The results of this study are as follows: 1. The values of Action Limit(AL) by the NIOSH 1981 lifting equation. Recommended Weight Limit(RWL) by the 1994 equation and the weight of the load handled at each manual lifting task were shown log-normal distributions. 2. LI'(the weight of tile load/AL) and LI(the weight of the load/RWL) were calculated estimate the physical stress imposed by each individual lifting task. As a result. 76.7% of the total LI' value exceeded 1 and 12.9% exceeded 3, and 84.7% of the total LI values exceeded 1 and 20.9% exceeded 3. 3. Bus 2 Department showed the highest rate of LI'>1 and LI>1 and Bus 1 Department showed the highest rate of LI'>3 and LI>3 4. In general, the RWLs by the 1994 equation were found lower than the ALs by the 1981 equation. It is assumed to he resulted from the fact that the 1994 equation includes methods evaluating asymmetrical lifting tasks and lifts of objects with less then optimal hand-container couplings, and also covers a larger range of work durations and lifting frequencies than the 1981 equation. 5. Significant correlations were found between LI' and incidence of LBP (R=0.734, p<0.05). LI and incidence of LBP(R=0.671. p<0.10) and load-weights and incidence of LBP(R=0.797, p<0.05). 6. Control measures are required to achieve the value of LI less than 1 for some tasks having high LI values. Engineering control is highly recommended for some tasks having the value of LI above 3.