• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.90-92
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• 1993

Stability analysis is an essential work in the operation and planning of power system. There are two categories, direct method and indirect method, and indirect method calculates the trajectories of states by numerical methods. Popular method using explicit integration has relatively low accuracy, so a more accurate method is requested. By the consideration of bus voltage variation, Runge-Kutta 4th order method can be made more accurate, but this scheme need much computation time. Through three recipes, computational cost of proposed method can be reduced. So the proposed method has improved accuracy and slight rise in cost. the method was tested on the IEEE 14 bus system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.781-785
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• 2005

Cutting forces and tool deflection in end milling are represented as the closed form of tool rotational angle and cutting conditions. The discrete cutting forces caused by tool entry and exit are continued using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping pan are considered for cutting forces and tool deflection estimation. Compared to numerical methods, the presented method has advantages in short prediction time and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the ferm accuracy is easily predicted by tool deflect ion curve.

• 한국보육지원학회지
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• 제14권6호
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• pp.1-18
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• 2018

Objective: The purpose of this study was to investigate relationships among child care teachers' role conflict, organizational commitment and teacher's sensitivity. It also aimed to test the mediating effect of organizational commitment on the pathway from child care teachers' role conflict on teacher's sensitivity. Methods: A self-report survey was conducted on 301 child care teachers in Chungbuk. Descriptive, means, standard deviations, correlations using SPSS 18.0, and Structural Equation Modeling using AMOS 18.0 were all conducted in order to analyze the collected data. Results: The results indicated that child care teachers' role conflict and organizational commitment had significant direct effects on teacher's sensitivity. This study also confirmed the significant mediating role of organizational commitment on the pathway from child care teachers' role conflict to sensitivity. Conclusion/Implications: The significance of role conflict and organizational commitment suggests that the integration of individuals with less conflict and more dedication will contribute more qualitative child care services by improving sensitive interactions with young children.

• 대한의용생체공학회:의공학회지
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• 제37권5호
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• pp.168-177
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• 2016

In this paper we present an implantable pressure sensor to measure real-time blood pressure by monitoring mechanical movement of artery. Sensor is composed of inductors (L) and capacitors (C) which are formed by microfabrication and direct bonding on two biocompatible substrates (quartz). When electrical potential is applied to the sensor, the inductors and capacitors generates a LC resonance circuit and produce characteristic resonant frequencies. Real-time variation of the resonant frequency is monitored by an external measurement system using inductive coupling. Structural and electrical simulation was performed by Computer Aided Engineering (CAE) programs, ANSYS and HFSS, to optimize geometry of sensor. Ultrafast laser (femto-second) cutting and MEMS process were executed as sensor fabrication methods with consideration of brittleness of the substrate and small radial artery size. After whole fabrication processes, we got sensors of $3mm{\times}15mm{\times}0.5mm$. Resonant frequency of the sensor was around 90 MHz at atmosphere (760 mmHg), and the sensor has good linearity without any hysteresis. Longterm (5 years) stability of the sensor was verified by thermal acceleration testing with Arrhenius model. Moreover, in-vitro cytotoxicity test was done to show biocompatiblity of the sensor and validation of real-time blood pressure measurement was verified with animal test by implant of the sensor. By integration with development of external interrogation system, the proposed sensor system will be a promising method to measure real-time blood pressure.

• International Journal of Aeronautical and Space Sciences
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• 제11권1호
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• pp.10-18
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• 2010

The purpose of this paper deals with direct multiple-shooting method (DMS) to resolve helicopter maneuver problems of helicopters. The maneuver problem is transformed into nonlinear problems and solved DMS technique. The DMS method is easy in handling constraints and it has large convergence radius compared to other strategies. When parameterized with piecewise constant controls, the problems become most effectively tractable because the search direction is easily estimated by solving the structured Karush-Kuhn-Tucker (KKT) system. However, generally the computation of function, gradients and Hessian matrices has considerably time-consuming for complex system such as helicopter. This study focused on the approximation of the KKT system using the matrix exponential and its integrals. The propose method is validated by solving optimal control problems for the linear system where the KKT system is exactly expressed with the matrix exponential and its integrals. The trajectory tracking problem of various maneuvers like bob up, sidestep near hovering flight speed and hurdle hop, slalom, transient turn, acceleration and deceleration are analyzed to investigate the effects of algorithmic details. The results show the matrix exponential approach to compute gradients and the Hessian matrix is most efficient among the implemented methods when combined with the mixed time integration method for the system dynamics. The analyses with the proposed method show good convergence and capability of tracking the prescribed trajectory. Therefore, it can be used to solve critical areas of helicopter flight dynamic problems.

• 대한감각통합치료학회지
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• 제16권2호
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• pp.50-63
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• 2018

목적 : 본 연구는 부모-아동 상호작용치료가 장애아동 부모의 양육기술과 아동의 문제행동에 미치는 영향을 메타분석으로 검증하여 중재 방법의 근거를 제공하고자 한다. 연구방법 : 본 연구는 2007년 1월부터 2018년 3월까지 출판된 연구 중 장애아동을 대상으로 부모-아동 상호작용 프로그램을 사용한 연구를 대상으로 하였다. 논문 검색은 PubMed, CINAHL, EBSCOhost, Science Direct를 이용하였고, 이차적으로 검색논문의 참고문헌을 추가 검색하였다. 총 7편의 연구가 선정기준에 적합하였고, 최종 논문에 대해 Jadad scale를 이용하여 질적 평가를 수행하였다. R-meta 분석프로그램을 사용하여 통계적 검정을 실시하였다. 결과 : 부모-아동 상호작용치료의 양육기술 효과크기는 큰 효과크기를 나타냈으며, 양육 스트레스 효과크기는 중간크기를 나타냈다. 아동의 문제행동 또한 중간 효과크기를 나타냈으며 모든 p값은 통계적으로 유의하였다(p<.0001). 결론 : 본 연구는 부모-아동 상호작용치료가 부모의 양육기술과, 양육 스트레스, 아동의 문제행동에 미치는 영향을 살펴보았다. 앞으로 아동작업치료에서 가족참여 중재에 대한 근거 마련을 위한 연구가 필요하다.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권1호
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• pp.17-26
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• 2004

Pest monitoring through field surveys and surveillance helps in forecasting the population build up of pest. It reduces the load of pesticides application and forms the basis of Integrated Pest Management in sericulture. Common sampling techniques for quantifying pest populations and damage caused by them are reviewed emphasizing the need for quick and simple sampling methods. Various direct and indirect sampling methods for establishing pest populations are discussed and methods have been discussed to use indirect sampling method under IPM programme in sericulture. The use of pheromone lures and traps forms one of the important ingredients of integrated pest management, which calls for integration of all available methods in a cost effective and environmental friendly manner offering consistent efficacy. Silk-worms feed on the variety of silk host plants and spin cocoons. Each silk host plant is attacked in the field by number of insect pest species. Several pests are common to mulberry, tasar, oak tasar, muga and eri host plant but pest status and seasonal abundance differs from each crop. The key pests are serious perennially occurring persistent species which cause considerable yield loss every year on large areas and require control measure. Regular occurrence of minor pest is noticed but sudden increase in its population is not known. The occasional pests are sporadic but potential causing sufficient damage. Silk losses due to attack of all the pests have not been calculated. However, information on pest biology and ecology, and control practices being practiced is available but the period of outbreak of major pests and predators on silkworms and its host plant needs to be reinvestigated. Pest and predators forecasting based on surveillance information may provide an opportunity to minimize the losses, particularly to reduce expenditure involved in pest management.

• 대한감각통합치료학회지
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• 제20권3호
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• pp.72-85
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• 2022

목적 : 본 연구는 발달성협응장애 아동을 대상으로 인지기반 작업수행 중재의 목표 활동, 중재 방법 및 중재 효과, 평가도구에 관한 정보를 수집하고 분석하여 중재 효과에 대한 근거를 제시하고자 하였다. 연구방법 : 본 연구는 2012년 1월부터 2022년 10월까지 게재된 논문을 대상으로, PubMed, Embase, ScienceDirect, Cochrance Library 데이터베이스를 이용하여 검색하였다. 검색어는 ('developmental coordination disorder' OR 'DCD') AND ('Cognitive Orientation to daily Occupational Performance' OR 'Cognitive Orientation to Occupational Performance' OR 'CO-OP')이었다. 검색된 211편 중 선정기준과 배제기준에 따라 총 7편의 논문을 선정하여 분석하였다. 연구결과 : 대상 문헌은 무작위 대조군 연구가 2편, 비무작위 두 집단 연구가 1편, 비무작위 한 집단 연구가 3편, 단일 대상 연구가 1편으로 전반적으로 근거 수준이 높게 나타났다. 중재의 목표 활동은 놀이, 교육, 일상생활활동 영역 순으로 선호도가 높았다. 인지기반 작업수행 중재는 대부분 한 회기에 1시간씩, 10회기로 진행하였으며, 작업수행과 운동기술에 긍정적인 효과가 있는 것으로 나타났다. 중재의 효과는 주로 Canadian Occupational Performance Measure(COPM)과 Performance Quality Rating Scale(PQRS)을 이용하여 작업수행 향상을, Movement Assessment Battery for Children(MABC)를 이용하여 운동 기술 향상을 평가하였다. 결론 : 본 연구는 발달성협응장애 아동의 인지기반 작업수행 중재 적용에 있어 임상적 기초자료로 활용될 수 있을 것으로 보인다.

• 문화기술의 융합
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• 제10권3호
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• pp.551-557
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• 2024

유아문화예술교육은 자신을 표현하면서 사회를 이해하는 과정으로 유아의 삶 전반에 큰 영향을 준다. 유아마다 발달 특성이 다르기에 개별적 다양성을 고려해야 한다는 개별화의 원리와 유아들이 놀이를 통한 즐거움으로 체험활동에 대한 적극적인 태도를 형성하는 놀이 중심의 원리, 전인적인 발달에 밑받침이 되는 통합적 원리, 유아가 직접 만지고 조작해 보는 경험을 제공하는 직접경험의 원리를 활용하였다. 도입에서는 통한 재료의 탐색과 생각나누기, 다함께 책을 읽고 나누기를 진행하고, 전개1과 전개2에서는 문화예술영역인 미술, 음악, 신체표현, 동극, 영화, 사진 등 예술적 표현을 즐기면서 자신의 생각을 창의적으로 표상하도록 하였다. 마무리 단계에서는 유아가 창출해낸 결과물을 함께 감상하고 자신의 생각을 발표하는 과정으로 서로의 의견을 나눌 수 있는 시간으로 구성한 교수학습지도안을 개발하였다. 유아문화예술교육을 통한 교육적 효과는 유아들이 자신의 흥미에 따라 탐구하는 학습이 강조되는 유아기에 개발하는 것이 효과적이므로, 이 연구에서는 유아문화예술교육에 적용할 수 있는 다양한 교육방안과 장르의 융합적 교육이 반영된 학습지도방안을 제시하였다.

• Environmental Engineering Research
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• 제12권5호
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• pp.231-237
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• 2007

The microbial eco-physiology has been the vital key of microbial ecological research. Unfortunately, available methods for direct identity of microorganisms and for the investigation of their activity in complicated community dynamics are limited. In this study, metagenomics was considered as a promising functional genomics tool for improving our understanding of microbial eco-physiology. Its potential applications and challenges were also reviewed. Because of tremendous diversity in microbial populations in environment, sequence analysis for whole metagenomic libraries from environmental samples seems to be unrealistic to most of environmental engineering researchers. When a target function is of interest, however, sequence analysis for whole metagenomic libraries would not be necessary. For this case, nucleic acids of active populations of interest can be selectively gained using another cutting-edge functional genomic tool, SIP (stable isotope probing) technique. If functional genomes isolated by SIP can be transferred into metagenomic library, sequence analysis for such selected functional genomes would be feasible because the reduced size of clone library may become adequate for sequencing analysis. Herein, integration of metagenomics with SIP was suggested as a novel functional genomics approach to study microbial eco-physiology in environment.