• 산업공학
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• 제23권4호
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• pp.327-336
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• 2010

We consider a supply chain consisting of a make-to-order manufacturer and N component suppliers and study the impacts of the number of suppliers on component inventory management. The manufacturer has full information and continuously observes the state of both component inventory level and customer backorders. Based on this information, the manufacturer determines whether or not to place a component purchasing order to a supplier among N suppliers even though some orders are in process by other suppliers. The goal of this paper is to numerically identify the manufacturer's purchasing policy which minimizes the total supply chain cost and the best choice of N. Our model contributes to the current literature in that the problem of simultaneously considering multiple outstanding orders and incorporating order setup cost into the model has not been covered yet. From numerical experiment, we investigate how much the policy with N suppliers can contribute to reducing the supply cost compared to the policy with a single supplier.

• 음성과학
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• 제1권
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• pp.137-152
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• 1997

The objectives of this paper are to see how the declination is realized in the different positions/lengths of the utterance, to see if the $F_0$ value throughout the utterance changes in a predictable way, and if so, to find out the best quantitative model which fits the declination. The experiment results are as follows. First, the peak value over the utterance can be affected by the position of the peak and length of the utterance. Second, the choice of quantitative models is dependent on the different list lengths. Third, in everyone's speech, there is a baseline (the lowest $F_0$ value a speaker can use), and the $F_0$ will not fall below the baseline. Forth, the peak $F_0$ of the last word in each list shows little variation in pitch value (target $F_0$) while the number of words in the list affects the starting $F_0$ values.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 학술대회 논문집
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• pp.321-326
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• 2005

Interior permanent magnet synchronous motor(IPMSM) has become a popular choice in electric vehicle applications, due to their excellent power to weight ratio. The paper is proposed maximum torque control of IPMSM for high speed drive. The control method is applicable over the entire speed range and considered the limits of the inverter's current and voltage rated value. For each control mode, a condition that determines the optimal d-axis current $^i{_d}$ for maximum torque operation is derived. The proposed control algorithm is applied to IPMSM drive system for high speed drive, the operating characteristics controlled by maximum torque control are examined in detail by experiment.

• 대한산업공학회지
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• 제16권1호
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• pp.83-98
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• 1990

Previous studies have shown strong tendancy toward overconfidence in intuitive probability judgements. The purpose of the present study is to investigate the relations between this overconfidence phenomenon and the three major characteristics of information, namely, the pertinance, the redundancy and the quantity. An experiment was conducted where the subjects were asked to respond to 120 questions of the same type. In each question, the subjects' task was to predict, in the light of given information, which of the two given countries would have had higher GNP in 1979 and to give the probability that their choice would be correct. The results suggests that only the pertinance of information has significant influence on the degree of overconfidence.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.401-402
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• 2005

The important parts of material science in the film preparation fields and sol-gel technology are presented. For the present work, a series of amorphous films was prepared in air by sol-gel method without using some alkoxide stabilizer, which reduces the reactivity of the metal alkoxides. The choice of precursors can affect the chemical-reaction kinetics, microstructures and properties of the product. In this report author compared the crystallization behavior of oxide functional films derived from the same precursors, stressing the influence of experiment conditions and where it was possible to obtain the uniform amorphous or crystalline dielectric films. A short analysis of sol-gel technology and thin film methods about development of dielectric materials has been given.

• 대한화학회지
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• 제65권2호
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• pp.145-150
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• 2021

The present study describes a hands-on experiment to help students understand the concept of phase change or phase transition and its application in a phase change material (PCM). PCMs are substances that have the capability of storing and releasing large amounts of thermal energy. They act as energy storage materials that provide an effective way to save energy by reducing the electricity required for heating and cooling. Lauric acid (LA) was selected as an example of the PCM. Students investigated the temperature change of LA and the temperature (of air) inside the test tube. The differences in the temperatures of the systems helped students understand how PCMs work. A one-group pretest and posttest design was implemented with 34 grade-11 students in science and mathematics. Students' understanding was assessed using a multiple-choice test and a questionnaire. The findings revealed that the designed activity helped students understand the concept of phase change and its application to materials for thermal energy storage.

• 한국양봉학회지
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• 제32권4호
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• pp.295-302
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• 2017

Avoidance behavior is an important life history strategy to survive hazardous environment. The experiment was conducted to detect the avoidance tendency of the honeybee Apis mellifera against commonly used pesticides in apple production. Choice test given only 50% sucrose solution and pesticide-mixed sucrose solution as food estimated the avoidance in laboratory. Most of the acaricides and fungicides tested were shown avoided. Among insecticides, honeybee showed strong avoidance to cyhexatine, carbosulfan and fenpyroximate but low to diflubenzuron, tebufenpyrad, and acrinathrin. Avoidance behavior to neonicotinoid insecticides showed bifurcated; highly avoided from thiacloprid, acetamiprid while less avoided from imidacloprid, thiamethoxam and dinotefuran. From the field study, abamectin, fenthion, amitraz and acequinocyl showed highly avoided while fungicide of fenarimol, acaricides of acrinathrin and phosphamidon, IGR insecticide of diflubenzuron, neonicotinoid insecticide of imidacloprid, and carbamate insecticide of carbaryl showed less avoidance in the field. These results partly explained high bee poisoning from carbaryl in apple flowering period, and neonicotinoids during season.

• International Journal of Advanced Culture Technology
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• 제12권3호
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• pp.250-256
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• 2024

This study aims to examine the impact of perceived control on individuals' state boredom. We hypothesized that perceived control is negatively correlated with state boredom and is anticipated to be a significant predictor of state boredom after controlling for pre-task boredom. An experiment was conducted with 98 university students. All participants engaged in an identical task designed to induce boredom, with only participants in the experimental group given a choice during the task to enhance their perceived control. Correlational analysis revealed a significant negative relationship between perceived control and state boredom. Hierarchical regression analysis demonstrated that perceived control remained a significant predictor of post-task boredom even after controlling for pre-task boredom. The study concludes with a discussion of the limitations, the implications of the findings, and suggestions for future research.

• 정보관리학회지
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• 제24권4호
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• pp.267-283
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• 2007

이 연구에서는 분포 유사도를 문헌 클러스터링에 적용하여 전통적인 코사인 유사도 공식을 대체할 수 있는 가능성을 모색해보았다. 대표적인 분포 유사도인 KL 다이버전스 공식을 변형한 Jansen-Shannon 다이버전스, 대칭적 스큐 다이버전스, 최소스큐 다이버전스의 세 가지 공식을 문헌 벡터에 적용하는 방안을 고안하였다. 분포 유사도를 적용한 문헌 클러스터링 성능을 검증하기 위해서 세 실험 집단을 대상으로 두 가지 실험을 준비하여 실행하였다. 첫 번째 문헌클러스터링실험에서는 최소스큐다이버전스가 코사인 유사도 뿐만 아니라 다른 다이버전스공식의 성능도 확연히 앞서는 뛰어난 성능을 보였다. 두번째 실험에서는 피어슨 상관계수를 이용하여1차 유사도 행렬로부터2차 분포 유사도를 산출하여 문헌 클러스터링을 수행하였다. 실험결과는 2차 분포 유사도가 전반적으로더 좋은 문헌 클러스터링성능을 보이는 것으로 나타났다. 문헌클러스터링에서 처리 시간과 분류 성능을 함께 고려한다면 이 연구에서 제안한 최소 스큐 다이버전스 공식을 사용하고, 분류 성능만 고려할 경우에는 2차 분포 유사도 방식을 사용하는 것이 바람직하다고 판단된다.

• 한국의류산업학회지
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• 제12권4호
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• pp.531-537
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• 2010

The purpose of this study was to review physiological responses and subjective sensations in the cold environment when the subjects wore ensemble with different clo values. Seven healthy male subjects participated in this experiment. This experiment was conducted in a climatic chamber with $-10^sC$ and 50%RH. Subjects wore five different kinds of ensemble[C1 (4.453 clo), C2 (3.452 clo), C3 (2.865 clo), C4 (2.387 clo), and C5 (2.280 clo)]. The experiment was composed of 20 min of rest period, 20min of treadmill exercise(6 km/h) period, 30 min of recovery period. We monitored skin temperature on 7 sites, clothing microclimate and subjective sensations. The clo value had positive correlations with mean skin temperature and clothing microclimate. The subjects feel more warm and humid as the clo value goes up. The subjects reported comfort when they wore C1 and C2 ensemble having over 3 clo value. However, they felt less comfortable during the exercise period since there was high humidity. Skin temperature on the extremities were more dramatically changed by the exercise rather than clo value. Thus it seems that in the cold environment, heat balance can mostly be controlled by the choice of clothing, and the clothes with high clo values can provide higher insulation. In conclusion, our findings suggest that it would be more effective to control clo value depending on the activity level for maintaining comfort level in the cold environment.