• 전력전자학회논문지
• /
• 제4권5호
• /
• pp.413-422
• /
• 1999

Auto-connected multipulse(12/24pulse) rectifier schemes are cost effective methods for reducing line current hamonics in PWM drive systems. Employing these schemes to enhance utility power quality requires careful attention to several design considerations In particular, excursion of dc-link voltage at no load, effect of pre-existing voltage distortion, impedance mismatches, unequal diode drops on rectifier current sharing and performance, are fully analyzed, Several corrective measures to improve the performance of 12/24­pulse rectifier systems are also discussed. Finally, experimental results on a 460V, 60Hz 400kVA commercial ASD, retrofitted with 12/24pulse rectifier systems are discussed in detail.

• 대한전기학회논문지
• /
• 제40권1호
• /
• pp.47-57
• /
• 1991

A new control algorithm so called equal excursion sliding mode (EESM) control method is proposed to control the position of DC servo motor. This method introduces the concept of phase velocity vector that Filippov presented, and simplifies the problem of control gain selection in a conventional VSC strategy. And, by making state trajectories have equal excursions on both sides of switching hyperplane we minimized the probability of sliding mode's being collapsed, and approximated to the ideal sliding moed. Also, we proved the validity of this method by comparing the application results of this method to DC servo motor with those of conventional VSC strategy.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제27권3호
• /
• pp.288-297
• /
• 2005

Rehabilitation of the paralyzed face as a result of trauma or surgery remains a daunting task. Complete restoration of emotionally driven symmetric facial motion is still unobtainable, but current techniques have enhanced our ability to improve this emotionally traumatic deficit. Problems of mass movement and synkinesis still plague even the best reconstructions. The reconstructive techniques used still represent a compromise between obtainable symmetry and motion at the expense of donor site deficits, but current techniques continue to refine and limit this morbidity. In chronically paralyzed face, direct nerve anastomosis, nerve graft, or microvascular-muscle graft is not always possible. In this case, regional muscle transposition is tried to reanimate the eyelid and lower face. Regional muscle includes maseeter muscle, temporalis muscle and anterior belly of the digastric muscle. Temporalis muscle is preferred because it is long, flat, pliable and wide-motion of excursion. In order to reanimate the upper and lower eyelid, Upper eyelid Gold weight implantion and lower eyelid shortening and tightening is mainly used recently, because this method is very simple, easy and reliable.

• 대한치과보철학회지
• /
• 제22권1호
• /
• pp.17-22
• /
• 1984

A clinical evaluation was made on teeth in 113 subjects from ages 19 to 23 with Angle's Class I occlusion who were free from prosthesis, orthodontics, and occlusal equilibration. The study was made to determine if there was a relation between the type of occlusion, non-working contact and temporomandibular dysfunction. From the foregoing study, the author obtained the following results. 1. In lateral excursion, there was not any significant difference between bilateral canine protected occlusion (31%), bilateral group function (32.7%), and mixed type (34.5%). 2. Only 10 of 113 subjects studied had non-working side tooth contacts (8.2 per cent). 3. Twenty per cent of subjects with non-working side contact showed temporomandibular joint dysfunction. 4. Non-working side contacts were not observed in subjects with canine guided occlusion. 5. It would be premature to relate the type of occlusion on working side directly to temporomandibular joint dysfunction.

• 한국운동역학회지
• /
• 제22권3호
• /
• pp.261-268
• /
• 2012

The purpose of this study was to qualitatively analyze pressure intensity and the center of pressure(COP) trajectory according to shoe type. Subjects were ten first-year female university students. The EMED-AT 25/D(Novel, Germany) was used to measure pressure intensity and COP trajectory. The COP Excursion Index(CPEI) was used for within subject test design. Independent variables were bare feet and six types of shoes. Dependent variables were center of pressure trajectory and pressure intensity. Barefeet and five toed shoes had a similar pressure intensity and COP trajectory. COP trajectory for all other shoe types showed a medial wobble at the heel. Pressure intensity for all other shoe types was related to the structure of the shoes. In conclusion, different shoe types can not only affect gait, but they can also influence foot deformities, pain, and dysfunction.

• Journal of Power Electronics
• /
• 제11권2호
• /
• pp.211-217
• /
• 2011

The dynamic response of a multi-MW wind turbine to a sudden change in wind speed is usually slow, because of the slow pitch control system. This could cause a large excursion of the rotor speed and an output power over the rated. A feedforward pitch control can be applied to minimize the fluctuations of these parameters. This paper introduces the complete design steps for a feedforward pitch controller, which consist of three stages, i.e. the aerodynamic torque estimation, the 3-dimensional lookup table for the wind seed estimation, and the calculation of the feedforward pitch amount. The effectiveness of the feedforward control is verified through numerical simulations of a multi-MW wind turbine.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
• /
• pp.40-40
• /
• 2003

최근 나노기술의 발달과 더불어 나노재료에 대한 특성평가 요구가 높아지고 있고, 따라서 나노스케일에서 재료의 기계적 거동을 분석할 수 있는 나노인덴테이션 기법이 심도있게 연구되고 있다. 본 연구에서는 나노인덴테이션, 주사탐침현미경(SPM), 투과전자현미경(TEM) 기법을 이용하여 여러가지 재료의 탄성 소성 변형 거동과 팝인/괍아웃 현상을 조사하고 해석하였다. 나노인덴테이션 기법으로는 50 마이크로뉴턴 (5 mg) 이하의 매우 작은 하중 하에서는 접촉 응력조건이라도 인장시험에서 관찰되는 영구변형이 제로인 완전탄성 변형 거동을 관찰할 수 있었다. 또한, 50-250 마이크로 뉴턴의 하중 범위에서 재료는 탄성변형 이후에 갑작스런 항복거동과 더불어 수십-수백 나노미터를 미끌어지듯 변형하는 팝인(pop-in), 또는 탈선(excursion) 현상을 관찰할 수 있었다. 이 현상은 하중을 가하는 동안에 여러 번 발생하였으며 재료의 표면상태와 전위밀도와 밀접한 상관관계를 보였다. 반복 압입 시험에서는 전형적인 가공경화 현상으로 항복점이 높아지고 새로운 항복점 이후에야 다시 팝인 발생함을 보였다. 한편, 하중을 가할 때 발생하는 팝인과는 달리 하중을 제거할 때 급격히 회복하는 팝아웃 현상 또한 관찰되었다.

• 한국해양공학회지
• /
• 제1권1호
• /
• pp.73-83
• /
• 1987

한국형 해저원유 초기생산 시스템은 제주도 남쪽의 한.일 공동개발구역 및 이와 유사한 조건의 지역에서 소규모 유전이 발견되었을때, 빠른 시간내에 저렴한 초기투자비로 석유를 생산할 수 있도록 개발되었다. 이 시스템은 원유저장용 선박, tower, yoke, gravity base 및 원유처리장치들로 구성되어 있으며 각 구조믈들은 pin 또는 universal joint들로 연결되어있다. 본 구조물의 파도중에서의 동적거동은 전산 program을 이용하여 구하여 wave tank에서 수행된 실험의 결과와 비교, 검토하였다. 그리고 이들 결과를 이용하여 구조적 안전성을 검토하였으며, 설계, 해석 및 model test의 결과들은 선급협회의 승인을 받았다.

• Journal of Chest Surgery
• /
• 제13권2호
• /
• pp.154-157
• /
• 1980

A twenty three year old, Primigravida and 32 week pregnant woman who has been complained dyspnea, chest pain, nausea and vomiting was admitted to this chest surgical department on Feb. 19, 1979. Physical findings were those of acutely ill appearance, decreased thoracic excursion and absence of breath sounds in the left hemithorax. Roentgen examination of the chest revealed reticular cystic densities in the left, particularly in lower lung field with collapse of the left lung. Correction of the diaphragmatic hernia was carried out with reduction and repair of the hernia through transperitoneal approach. On exploration, the defect of the diaphragm was 12 x 12 cm in size and was located posterolateral area of left diaphragm. Hernia contents were stomach, spleen, omentum and splenic flexure of large bowel. The baby was normal full term spontaneous delivered at 36th POD. Diaphragmatic hernia complicated by pregnancy is a rarity and mortality is extremely high. Therefore, the literatures have reviewed and the case is reported.

• 한국자동차공학회논문집
• /
• 제11권3호
• /
• pp.20-27
• /
• 2003

In this paper, the fuel transport characteristics during transient condition was studied by using a Fast Response Flame Ionization Detector(FRFID). The quantitative measurement method for the inducted fuel mass into cylinder is studied. The inducted fuel mass into the cylinder was estimated by using calculated air-fuel ratio by hydrocarbon concentration of cylinder and air flow model. In order to estimate the transportation of injected fuel from the intake port into cylinder, the wall wetting fuel model was used. The two coefficient $\alpha$,$\beta$) of the wall-wetting fuel model was determined from the measured fuel mass that was inducted into the cylinder at the first cycle after injection cut-off To reduce an air/fuel ratio fluctuation during rapid throttle opening, the appropriate fuel injection rate was obtain from the wall wetting model with empirical coefficients. Result of air/fuel ratio control, air/fuel excursion was reduced.