• Journal of the Korean Data and Information Science Society
• /
• 제17권3호
• /
• pp.905-912
• /
• 2006

Support vector classification(SVC) provides more complete description of the linear and nonlinear relationships between input vectors and classifiers. In this paper we propose to solve the optimization problem of SVC with a modified hinge loss function, which enables to use an iterative reweighted least squares(IRWLS) procedure. We also introduce the approximate cross validation function to select the hyperparameters which affect the performance of SVC. Experimental results are then presented which illustrate the performance of the proposed procedure for classification.

• 한국광학회지
• /
• 제12권2호
• /
• pp.77-82
• /
• 2001

손실 200 ppm급과 30 ppm급인 두 종류의 시험 반사경을 대상으로, 지수감쇠 방법을 이용한 반사경 손실측정 시스템의 오차 특성이 조사되었다. 공진기 길이 떨림에 의한 공진기 감쇠신호의 지수함수 왜곡을 보상하기 위하여 감쇠신호 데이터 평균기법을 적용하였다. 감쇠신호 6개의 평균이 취해졌을 때 감쇠신호의 지수함수 곡선맞춤 오차개선이 뚜력시 관측되었으며 손실 200ppm급 시험 반사경의 경우 약 2.4배 손실 30ppm급 시험 반사경의 경우 약 1.3배의 반사경 손실 측정오차 개선효과를 얻을 수 있었다 시험 공진기에서의 일별(day-to-day) 반사경 손실측정 반복도 오차가 조사되었다. 손실 200ppm급 시험 반사경의 경우 약 5.0%, 30ppm급 시험 반사경의 경우 약 26.4%의 손실측정 반복도 오차가 관측되었다. 저손실 반사경 평가에서 확인된 낮은 감쇠신호 데이터 평균효과와 높은 손실측정 반복도 오차는 손실측정 시스템 자체의 측정오차 이외에 시험 반사경 표면의 불균일한 손실 공간분포와 주변 오염원 유입의 결과로 분석되었다 또한 공진기 길이 떨림의 크기와 공진기 길이 측정오차가 손실측정 시스템의 정확도에 미치는 영향을 계산을 통해 조사한 결과, 분해능 수 ppm 급 현재의 측정 시스템의 성능에 미칠수 있는 공진기 길이오차의 영향은 충분히 적은 것으로 확인되었다.

• 반도체디스플레이기술학회지
• /
• 제23권2호
• /
• pp.50-54
• /
• 2024

In this paper, we propose a theoretical method to systematically analyze the power conversion efficiency of a single-phase PFC switching rectifier. Boost-type PFC was organized in order of highest correlation with load current using steady-state analysis results and introduced the concept of loss factor. The loss factors for each major element are summarized and presented in a table. This paper makes it easier to understand the internal loss and power conversion efficiency of the rectifier for loss factors. Lastly, to confirm the validity of the efficiency analysis results reflecting the loss factors, loss and efficiency analysis of the 2.5kW PFC rectifier was performed. The results were compared with data from a 2.5kW PFC circuit for evaluation. As a result, the usefulness of power conversion efficiency analysis reflecting the loss factors proposed in this paper was confirmed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
• /
• pp.20-22
• /
• 2000

The transmission networks are not perfect conductors and a percentage of the power generated is therefore lost before it reaches the loads. This network loss contributes to the cost of suppling power to consumers, and must be considered if the most efficient dispatch and location of generators and loads is to be achieved. In this paper, we propose an approximate calculation of marginal loss factors to analyze characteristics of regional transmission loss. These static marginal loss factors are approximately calculated based on the KEPCO's expected summer peak load data of year 2000.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
• /
• pp.110-115
• /
• 2000

The mean streamline analysis using the empirical loss correlations has been developed for performance prediction of industrial mixed-flow fan impellers in the present study. New simple, but effective, models for the additional Euler input work characteristic and an internal recirculation loss due to internal flow reversal under the low flowrate conditions are proposed in this paper. Comparison of overall performance predictions with six sets of test data of mixed-flow fans is accomplished to demonstrate the accuracy of the proposed models. Predicted performance curves by the present set of loss models agree fairly well with experimental data for a variety of mixed-flow fan impellers over the entire operating conditions. The prediction method presented herein can be used efficiently in the conceptual design phase of mixed-flow fan impellers.

• 한국화재소방학회논문지
• /
• 제16권4호
• /
• pp.59-64
• /
• 2002

버터플라이 밸브의 압력손실과 캐비테이션에 대한 유동특성 연구를 수행하였다. 밸브의 열림각에 대한 압력손실계수는 Carnot 방정식을 응용하여 수식화하였다. 캐비테이션(캐비테이션의 발단, 슈퍼 캐비테이션, 캐비테이션 손상, 초킹 캐비테이션과 같은)은 밸브의 압력손실계수로부터 예측되었다. 압력손실과 캐비테이션 예측은 밸브의 열림각에 대한 두께 비의 변화에 따라 수행하였다. 예측 데이터는 버터플라이 밸브를 개발하는데 필요한 엔지니어링 데이터로 활용하고자 한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제53권11호
• /
• pp.658-663
• /
• 2004

According to the improvement of the HTS wires performance, several tapes of HTS superconducting machines are being developed. Stacked HTS tapes are used as conductor that can flow high current for the HTS power machines. To develop the HTS power machines, the critical current characteristics of a stacked HTS tapes in external filed and AC losses should be examined. In this paper, we present characteristic of the stacked HTS tapes and AC losses of HTS pancake windings with stacked tapes. AC loss of the pancake winding were measured and compared with the calculated loss by using AC loss data of the stacked samples and the magnetic flux density in the HTS winding under operating conditions. We can see that measured results generally agree well with the calculated results by using AC loss data of 4-stacked sample.

• Journal of the Korean Data and Information Science Society
• /
• 제25권3호
• /
• pp.685-696
• /
• 2014

In this paper, we develop Bayesian inference of the finite population mean with the assumption of posterior linearity rather than normality of the superpopulation in the presence of auxiliary information under the balanced loss function. We compare the performance of the optimal Bayes estimator under the balanced loss function with ones of the classical ratio estimator and the usual Bayes estimator in terms of the posterior expected losses, risks and Bayes risks.

• 대한기계학회논문집B
• /
• 제28권10호
• /
• pp.1247-1254
• /
• 2004

In momentum exchange theory the loss models for the circulatory flow is critically important. But because of lack of loss model on the circulatory flow, analysis model on regenerative turbomachines is not available in the open literature. In the present study circulatory loss is evaluated by combining bend's losses. Through the comparison with the previous experimental data on linear pressure gradient, a combination factor is suggested in terms of the aspect ratio of a channel. Applying this factor to two kinds of regenerative blowers the predicted results are found to be in good agreement with the experimental data of the overall performance and the head distribution along the rotational direction. Especially, the comparison with the head distribution demonstrates the accuracy of hydraulic model and loss model suggested in the present study. And the comparison with the overall performance confirms the validness of physical models as well as loss models suggested in the present study.

• 기본간호학회지
• /
• 제13권3호
• /
• pp.485-492
• /
• 2006

Purpose: The purpose of this study was to identify body satisfaction and weight loss experience according to individual's discrepancy between obesity by BMI (body mass index) and self-assessment. Method: The data were obtained by measuring height, weight and using a questionnaire to obtain data on self-assessment of obesity, body satisfaction and weight loss experience. The participants were 286 women college students in J city, Chungbuk. Results: The mean BMI of the women college student was $21.4{\pm}2.93kg/m^2$ which is within the normal range. The concordance rates between obesity by BMI and self-assessment were 54.1%, 39.9%, 61.5%, 78.6% (Kappa=.29) in underweight, normal, overweight, obese students respectively. Forty seven percent of students who were not obese (BMI $<23kg/m^2$) assessed themselves as obese. The mean body satisfaction of college students was very low and 64.3% of the students had a weight loss experience. The students who perceived themselves to be 'obese' even when their BMI was under $23kg/m^2$ reported lower body satisfaction and higher weight loss experience than other students. Conclusion: There were significant discrepancies between obesity by BMI and self-assessment in women college students. The self-assessment of obesity had a greater effect on body satisfaction and weight loss experience than actual BMI in women college students.