• 전기학회논문지
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• 제58권1호
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• pp.18-22
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• 2009

Short-term load forecasting (STLF) is an important task in power system planning and operation. Its accuracy affects the reliability and economic operation of power systems. STLF is to be classified into load forecasting for weekdays, weekends, and holidays. Due to the limited historical data available, it is more difficult to accurately forecast load for holidays than to forecast load for weekdays and weekends. It has been recognized that the forecasting errors for holidays are large compared with those for weekdays in Korea. This paper presents a polynomial regression with data mining technique to forecast load for holidays. In statistics, a polynomial is widely used in situations where the response is curvilinear, because even complex nonlinear relationships can be adequately modeled by polynomials over a reasonably small range of the dependent variables. In the paper, the coefficient of determination is proposed as a selection criterion for screening weekday data used in holiday load forecasting. A numerical example is presented to validate the effectiveness of the proposed holiday load forecasting method.

• International Journal of Costume and Fashion
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• 제8권1호
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• pp.53-64
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• 2008

This study defined luxury hanbok, categorized its consumers according to their lifestyles, and examined the differences between the lifestyle groups in preferred images of luxury hanbok and consumer habits. The subjects of the study were 216 luxury hanbok consumers resident in Seoul. The various types of statistical analyses used in this study were frequency, factor analysis, Cronbach's a, cluster analysis, ANOVA, Duncan-test and $X^2$-test. The results of this study were as follows: 1. The lifestyle of luxury hanbok consumers was classified broadly into 4 groups as: brand oriented, economic/appearance oriented, family oriented/socially oriented, self-driven/economic oriented. 2. The preferred images included these five factors: splendor, elegance, uniqueness, simplicity and tradition. The elegant image was aspired to by the brand oriented group. Meanwhile, the traditional image is sought after by both the brand oriented group and the economic/appearance oriented group. 3. The lifestyle groups differed significantly in the selection criterion such as material, brand and rarity. The brand oriented group placed greater importance on material, brand and rarity than other groups. 4. In addition, each group differed in their frequency of purchase, price range, and demographic characteristics.

• 대한기계학회논문집B
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• 제27권7호
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• pp.938-947
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• 2003

In this paper, we derived the formula for estimating the power of the electric motors needed to operate the Decanter-type centrifuge. In the derivation of the formula the sludge-removal torque is to be supplied from the formula derived in the first paper. The intricate nature of the transmission mechanism in the planetary gear trains of the sludge-removal power and torque has been clarified in this second paper. In particular we considered two-motor system, where the main motor drives the machine while the differential-speed control motor plays the role of braking in adjusting the differential speed. Sample calculation for the specific design treated in the first paper showed that the selection criterion for the main motor depends on the lower limit of the differential speed; when the lower limit is set low, it should be selected based on the steadily operating power, while it should be selected based on the starting power when the lower limit is set high. The total power required by both the main motor and the differential-speed control motor increases as the differential speed is decreased. It is suggested that the power loss in the differential-speed control motor could be minimized by attaching an electric generator to it.

• 대한간호학회지
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• 제42권4호
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• pp.453-465
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• 2012

Purpose: The study was done to develop a shared decision-making scale for end-of-life patients in Korea. Methods: The process included construction of a conceptual framework, generation of initial items, verification of content validity, selection of secondary items, preliminary study, and extraction of final items. The participants were 388 adults who lived in one of 3 Korean metropolitan cities: Seoul, Daegu, or Busan. Item analysis, factor analysis, criterion related validity, and internal consistency were used to analyze the data. Data collection was done from July to October 2011. Results: Thirty-four items were selected for the final scale, and categorized into 7 factors explaining 61.9% of the total variance. The factors were labeled as sharing information (9 items), constructing system (7 items), explanation as a duty (5 items), autonomy (4 items), capturing time (3 items), participation of family (3 items), and human respect (3 items). The scores for the scale were significantly correlated among shared decision-making scale, terminating life support scale, and dignified dying scale. Cronbach's alpha coefficient for the 34 items was .94. Conclusion: The above findings indicate that the shared decision-making scale has a good validity and reliability when used for end-of-life patients in Korea.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1458-1463
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• 2003

This paper presents an improved identification algorithm of active magnetic bearing rotor systems considering sensor and actuator dynamics. An AMB rotor system has both real and complex poles so that it is very hard to identify them together. In previous research, a linear transformation through a fictitious proportional feedback was used in order to shift the real poles close to the imaginary axis. However, the identification result highly depends on the fictitious feedback gain, and it is not easy to identify the additional dynamics including sensor and actuators at the same time. First, this paper discusses the necessity and a selection criterion of the fictitious feedback gain. An appropriate feedback gain minimizes dominant SVD(Singular Value Decomposition) error through maximizing rank deficiency. Second, more improvement in the identification is achieved through separating the common additional dynamics in all elements of frequency response matrix. The feasibility of the proposed identification algorithm is proved with two theoretical AMB rotor models. Finally, the proposed scheme is compared with previous identification methods using experimental data, and a great improvement in model quality and large amount of time saving can be achieved with the proposed method.

• 정보처리학회논문지B
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• 제13B권3호
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• pp.301-308
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• 2006

현재 여러 응용 프로그램에서 이미지 전체를 전송 및 복원하기보다는 이미지의 일부 특정 영역이나 사용자 위주의 관심영역(ROI: Region-of-Interest)에 대한 우선적 처리가 요구되고 있다. 이러한 우선적 처리는 JPEG2000 표준 ROI 코딩 방법들을 비롯하여, 이를 보완한 새로운 ROI 코딩 방법들에 대한 연구가 최근까지 활발하게 이루어지고 있다. 하지만 모든 응용에 적합한 ROI 코딩 방법은 존재하지 않는다. 본 연구는 JPEG2000 응용에서 적절한 ROI 코딩 방법을 적용하기 위하여 요구사항에 따른 ROI 코딩 방법의 선택 기준을 제시하고, 선택된 방법에 대하여 효율적인 매개변수 값을 결정할 수 있도록 실험 결과를 제시한다.

• 한국연초학회지
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• 제11권2호
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• pp.149-155
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• 1989

This study was conducted to obtain the breeding information for the leaf breakdown, and correlation coefficients between leaf breakdown and some agronomic characters in flue-cured tobacco at Taegu Experiment Station, Korea Ginseng & Tobacco Research Institute. NC 95 and NC 2326 were used as parents. The bulk method procedure was used from the F2 to the F4 generations, 54 plants were selected among F4, and 11 lines were selected among 54 F5 which based on high resistance to bacterial wilt compared with NC2326. The entries were composed of parents and 11 F6 advanced lines, and designed in randomized block with 3 replications. Plant seedlings were transplanted in 16 April. The number of breakdown leaf were investigated at flowering stage, 18 June. There were significant difference between NC 95 and NC 2326 for the number of breakdown leaf, number and weight of ground suckers, days to flower, yield and resistance to bacterial wilt, and similar results were appeared among lines. Estimated heritability in the broad-sense ranged from 59.3% to 87.4% for all characters. Most of genetic correlations were higher than phenotypic coefficients between characters. Number of breakdown leaf was positively correlated with days to flower, the number and weight of ground suckers, while it was negative to yield. One line among 11 had few breakdown leaf, low producted ground suckers and high resistance to bacterial wilt. Above results suggest that the number and weight of ground suckers can be use as a selection criterion for leaf breakdown even under the condition without leaf breakdown.

• 보건행정학회지
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• 제15권4호
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• pp.1-25
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• 2005

Legislation on pharmaceutical reimbursement decision using economic evaluation results was made in Korea in fm, but has yet to be fully implemented. We evaluated the quality of Korean economic evaluation studies of pharmaceuticals to understand gaps between legislation and implementation. From this evaluation, we propose policy options that might strengthen the research Infrastructure In order to support such studies. We reviewed 23 published studies for drugs conducted between 1996 and 2004. Evaluation criteria included methodological characteristics, healthcare system characteristics, population characteristics, and applicability of results. Large variation in study quality was observed, particularly with study design, outcome data, treatment patterns and interpretation. Korean clinical data used was mostly from observational studies of 1-2 hospitals. Foreign data was extracted from clinical trials that did not Include Asian population and their selection criterion was not clarified. With respect to treatment patterns, medical records and hospital bills were used without adjustment regarding area, hospital type, and others. And next frequent situation relied on expert opinion from academic physicians in specialty practice. preference measures, when used, were not elicited from the Korean population. $78.3\%$ of studies did not clarify the funding source. If the Korean economic evaluation policy is to provide meaningful data for decision makers, the quality of cost-effectiveness studies will need to improve dramatically. This may involve access to or creation of better data, more diverse funding, unproved training of researchers and evaluators, and partnerships with technology manufacturers.

• 품질경영학회지
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• 제46권1호
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• pp.27-38
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• 2018

Purpose: A large number of attributes with mixed levels are often considered in the conjoint analysis. In the cases where attributes have two or three levels, we research on the efficient design of survey questionnaire to estimate all the main effect and two factor interaction effects with a reasonable size of it. Methods: To reduce the number of questions in a questionnaire, the balanced incomplete block mixed level factorial design with minimum aberration was proposed by Lim and Chung (2016). Based on the number of questions and that of the respondents in that design, D-optimality criterion is adopted to find efficient designs where the main effect and two factor interaction effects are estimated. Results: The list of the number of questions and that of the respondents in efficient designs for survey questionnaire are recommended based on the D-efficiency of each design and the proposed selection criteria for the number of both questions and the respondents. By analyzing all the respondents survey data generated by the simulation study, we find the proper model. Conclusion: The proposed methods of designing survey questionnaires seem to perform well in the sense that how often the proper model is found in a simulation study where all the respondents survey data are generated by the simulation model.

• 한국구조물진단유지관리공학회 논문집
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• 제8권3호
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• pp.225-233
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• 2004

본 연구에서는 응답면기법을 이용하여 격납건물의 내진안전성 평가를 하였다. ABAQUS를 이용하여 하중, 저항과 해석에서의 랜덤변수를 고려한 구조해석을 수행하였고 이로부터 변수의 다항식으로 표현되는 구조물의 응답을 얻었다. 그리고 Level II에 의해 신뢰성해석을 하였다. 한계상태함수로는 콘크리트의 2축응력 상태를 고려하기 위해 Drucker-Prager 파괴기준을 이용하였다. 구조물의 수명, 지진의 연발생율과 조건부 파괴확률을 고려하여 격납건물의 파괴확률을 계산하였다. 또한 응답면기법의 안정적인 결과를 얻기 위해 표본점 선정에 대한 민감도해석을 수행하였다.