• 설비공학논문집
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• 제25권2호
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• pp.85-93
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• 2013

The proportional plus integral(PI) feedback control manner has been used in many general industrial fields such as refrigeration system because of its simple design process and favorable control performance. This paper deals with optimized PI controller design of the refrigeration system based on evaluation functions such as integrated absolute error(IAE). The suggested optimal PI gains can be easily calculated by a simple program and the optimal controllability satisfying the evaluation function can be assured. Furthermore, at the initial step of controller design, the suggested optimal gain is able to reflect some noise disturbances caused by an inverter which drives variable speed compressors. The validity of the suggested optimal gain is investigated by some simulations and experiments to verify its efficiency. From the results of comparing control performance between the optimal PI controller based on the evaluation function and the PI controller designed by the Matlab tuner which was known as the most popular gain tuner, the optimal PI controller showed more desirable control performance especially in transient responses.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.117-126
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• 2007

In this paper, we propose an early rehabilitation training system for the improvement of postural balance with multi-modality on a tilting bed. The integration of the visual, somatosensory and vestibular functions is significant to for maintaining the postural control of the human body. However, conventional rehabilitation systems do not provide multi-modality to trainees. We analyzed the characterization of postural control at different tilt angles of an early rehabilitation training system, which consists of a tilting bed, a visual feedback, a computer interface, a computer, and a force plate. The software that we developed for the system consists of the training programs and the analysis programs. To evaluate the characterization of postural control, we conducted the first evaluation before the beginning of the training. In the following four weeks, 12 healthy young and 5 healthy elderly subjects were trained to improve postural control using the training programs with the tilting bed. After four weeks of training, we conducted the second evaluation. The analysis programs assess (center of pressure) COP moving time, COP maintaining time, and mean absolute deviation of the trace before and after training at different tilt angles on the bed. After 4 weeks, the COP moving time was reduced, the COP maintaining time was lengthened, and the mean absolute deviation of the trace was lowered through the repeated use of vertical, horizontal, dynamic circle movement training programs. These results show that this system improves postural balance and could be applied to clinical use as an effective training system.

• Applied Biological Chemistry
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• 제45권1호
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• pp.18-24
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• 2002

본 연구는 보리등겨로 제조한 간장 맛의 특성을 찾기 위해서 수행되었다. 맛성분은 기기분석으로, 관능검사는 panel로, 그 외 통계적 처리의 방법 등을 이용하였다. 보리간장 맛성분은 유기산, 유리당 및 유리아미노산으로 분류하였으며, 이들과 관능검사 성적과의 단순상관으로 보리간장 맛의 품질을 결정하는 것은 불가능하였다. 중상관계수는 절대값의 대수 변환에서 가장 높게 나타났으며, 따라서 단계적 중회귀분석은 가장 설명력이 높으며, 표준오차가 적은 절대값의 대수 변환을 이용하여 실시하였다. 단계적 중회귀분석 결과, 보리간장 맛의 좋고 나쁨에 기여를 하는 성분은 짠맛, 구수한 맛 및 쓴맛을 내는 성분 순이었다.

• 한국과학교육학회지
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• 제5권2호
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• pp.81-88
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• 1985

The purpose of the study was to establish a new view of textbook which may contribute to the abolishment of the instruction mainly based on the only textbook and to the promotion of creativities of students. We first reviewed science textbooks and related teaching-learning materials of foreign countries with emphasis on the relationship among textbook and teaching-learning materials and practical use of them. In western countries the roles of traditional textbook has been changed. That is, various kinds of materials such as reading book, work-book, worksheet, experimental guidebook, filmstrips are used to raise effect of instruction besides of traditional type of textbook. Secondary, we identified the problems related to the science textbook-view of textbook, textbook contents, practical use of textbook-through opinion survey administered to principals akd teachers of elementary schools. The results of the survey are as follows; Concerning the view of textbook, most teachers did not recognize textbook as an absolute materials. They thought that textbook contents could be taught reorganized according to their judgements. On the contrary, teachers responded to the question of whether or not they follow contents of textbook as they are presented in it were approximately 30%. Further, more than 75% of them have seldom used instructional materials except textbooks. In order to revise the problems of our present textbook as stated above, a new view of textbook should be established. We, above all, established 4 basic premises for searching a new view of textbook. 1) Textbook should not be considered as the only material but as being at the center of various teaching -learning materials. 2) The importance of textbook should be illustrated Among Curriculum, textbook and related teaching-learning materials, instruction and evaluation. 3. Textbook contents should not be regarded as definitely fixed or absolute ones. 4. Human being can understand environment more fully by commanding his swnsory organ multilaterally. Under these premises we disscussed about curriculum and textbook, textbook, and instruction, akd evaluation method.

• 환경영향평가
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• 제29권4호
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• pp.272-285
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• 2020

본 연구에서는 3차원 기상 및 대기질 모델의 입출력 자료를 평가하는 데 필요한 통계 검증지표를 선별하고, 선정된 검증지표의 기준치를 조사하여 그 결과를 요약하였다. 여러 국내외 문헌과 최근 논문 검토를 통해 최종 선정된 통계 검증지표는 MB (Mean Bias), ME (Mean Error), MNB (Mean Normalized Bias Error), MNE (Mean Absolute Gross Error), RMSE (Root Mean Square Error), IOA (Index of Agreement), R (Correlation Coefficient), FE (Fractional Error), FB (Fractional Bias)로 총 9가지이며, 국내외 문헌을 통해 그 기준치를 확인하였다. 그 결과, 기상모델의 경우 대부분 MB와 ME가 주요 지표로 사용되어 왔고, 대기질 모델 결과는 NMB와 NME 지표가 주로 사용되었으며, 그 기준치의 차이를 분석하였다. 아울러 이들 통계 검증지표값을 이용하여 모델 예측 결과를 효과적으로 비교하기 위한 표출 도식으로 축구 도식, 테일러 도식, Q-Q (Quantile-Quantile) 도식의 장단점을 분석하였다. 나아가 본 연구 결과를 기반으로 우리나라의 산악지역의 특수성 등이 잘 고려된 통계 검증지표의 기준치 설정 등의 추가연구가 효과적으로 진행될 수 있기를 기대한다.

• 대한인간공학회지
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• 제24권2호
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• pp.45-49
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• 2005

The FSA(Force Sensitive Application) system measures hand force by using force resistance sensors. Compared to conventional hand force measurement systems such as Lafayette hand dynamometer and Jamar hydraulic hand dynamometer, the FSA system can be applied to analyze use of hand forces while the hand is manipulating objects for a task, However, the measurement performance of the FSA system has not been objectively evaluated. The present study tested the FSA system in terms of stability, repeatability, accuracy, and linearity. It is shown that the FSA system has good stability (CV$\leq$0.02) and linearity($R^2$=0.82), but has low repeatability(CV=$0.11{\sim}0.19$) and accuracy(22% of underevaluation on average). This performance result indicates that measurements from the FSA system should be used for relative comparison rather than for absolute comparison.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.41-42
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• 2015

The concrete aggregate generates carbon dioxide in production but its demanding is gradually increased in accordance with the depletion of natural resources. Therefore we evaluated compatibility and basic physical properties of Silicon manganese slag generated in iron production as an applicable concrete aggregate. In our test, the silicon maganese slag shows 2.8g/㎥ of density in 10mm of maximum particle size similar to a natural aggregate, and its absorption rate was 0.3% similar to the electric furnace slag. Unit volume weight and ratio of absolute volume was respectively 2,001㎏/㎥ and 51%. Strength properties of Silicon manganese slag will be evaluated with further studies and experiments.

• 한국도로학회논문집
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• 제18권4호
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• pp.77-82
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• 2016

PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2016년도 춘계학술대회
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• pp.162-177
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• 2016

The government conducted an aviation expert training project in 2013. But unfortunately, only pilots and international experts were targeted and aircraft maintenance engineers that are the most important to safety were not trainee to the training courses. More importantly, the more the absolute number of aircrafts increases, the more demand for aircraft maintenance engineers are going up as well. Through the evaluation indicators for the Government-Sponsored Program Fostering Aviation Personnel(aircraft maintenance engineers). it figured out factors associated with the Government-Sponsored Program Fostering Aircraft Maintenance Engineers and it suggested a baseline data necessary to inspect and manage professional training institutions. Thanks to the development of the evaluation indicators, it is highly expected that difference among institutions will be narrowed, elevated level of management of the institutions will help foster and yield satisfactory aircraft maintenance engineers.

• 전기학회논문지
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• 제56권7호
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• pp.1268-1274
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• 2007

A recently developed methods for the on-site calibration of the voltage transformer (VT) comparator system have been reviewed in the paper. The method utilizes the several traveling standards consisting of the VT, the non-reactive standard resistors, the wide ratio error VT, and the decade resistors. The VT is used for the absolute evaluation of a standard VT belonging to the industry. The non-reactive standard resistor and wide ratio error VT are used for the linearity check of errors in the voltage comparator of the industry. The decade resistors are used for evaluation of a VT burden of the industry.