• Management Science and Financial Engineering
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• v.11 no.3
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• pp.19-45
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• 2005

Collaborative filtering is one of the most common methods that e-commerce sites and Internet information services use to personalize recommendations. Collaborative filtering has the advantage of being able to use even sparse evaluation data to predict preference scores for new products. To date, however, no in-depth investigation has been conducted on how the data sparsity effect in customers' evaluation data affects collaborative filtering-based recommendation performance. In this study, we analyzed the sparsity effect and used a hybrid method based on customers' evaluations and purchases collected from an online bookstore. Results indicated that recommendation performance decreased monotonically as sparsity increased, and that performance was more sensitive to sparsity in evaluation data rather than in purchase data. Results also indicated that the hybrid use of two different types of data (customers' evaluations and purchases) helped to improve the recommendation performance when evaluation data were highly sparse.

• Journal of the Korean Society of Costume
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• v.55 no.7 s.98
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• pp.89-100
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• 2005

The purpose of this study was to find out differences of visual evaluation according to perceiver's personality(introvert-extrovert) and clothing styles. Subjects were 120 women in age from 18 to 31 years in Seoul. The stimuli of 7 clothing styles were used for visual evaluation. Three dimensions of visual evaluation were derived by falters analysis: elegance, activity individuality, and fashionability. The pants suit was estimated low in activity individuality and fashionability, but the hip-hop style high in activity individuality. The skirt suit was rated high in elegance, but the 8th length pants low in elegance. Personality had significant influences on the evaluation of activity individuality. Extrovert women perceived all stimuli to be more active and individual than introvert. Fashionability factor had an interaction effect by personality and clothing expenses. The introvert women in low clothing expenses group evaluated the stimuli to be more fashionable than the introvert in high clothing expenses group. There were significant differences in preference of all clothing styles according to personality. Extrovert women liked 8th length pants more than introvert. The introvert women in low clothing expenses group liked the skirt suit less than the extrovert.

• Journal of the Korean Institute of Educational Facilities
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• v.21 no.2
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• pp.33-39
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• 2014

In the case of low-rise buildings in seismic performance evaluation, lateral force resistance of the pillars affects the seismic performance of the building. Evaluation of the seismic performance of the column is determined by the holding performance is evaluated by comparing the shear strength and bending strength it was destroyed bylow intensity. In case of the school building, in order to install the large windows for ventilation and lighting of the partition walls are located between the pillars. The case of the pillars of these, shear failure occurs in the event of an earthquake is often, in the seismic performance evaluation, partition wall and the wall of the shim is evaluated ignoring, pillar of the general pillars If you have to calculate the results of the seismic performance distorted that are destroyed by bending behavior can be evaluated as often. Results of the study, when assessed by distinguishing the effective length of the column, it was found that when a seismic load is applied, it is possible to accurately predict the failure mode, reliable results of seismic performance evaluation of the school building.

• Korean Journal of Child Studies
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• v.16 no.2
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• pp.97-112
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• 1995

The purpose of this study was to investigate the effect of selected internal and situational factors on children's prosocial behaviors. While child's sex and trait empathy were chosen as internal factors, state empathy and social evaluation were regarded as situational factors. The subjects were 72 bays and 72 girls chosen from 288 eleven-year-olds. This selection was based on their emplathic scores measured by the Bryant Empathy Scale (1982). Half of the 144 children belonged to the high-trait empathic group and the other half to the low-trait empathic group. Within each of the high-and the low-trait empathic groups, equal numbers of boys and girls were randomly assigned to one of the two state empathy conditions and two social evaluation conditions. The state empathy conditions were divided into the arousal condition and the disregarding condition. To control social evaluation, subjects were led to believe that the experimenter either would or would not evaluate their donation of colorful ball-point pens to handicapped children. The data was analyzed by 4-way ANOVA [sex(2)${\times}$trait empathy(2)${\times}$state empathy(2)${\times}$social evaluation(2)]. The results were that (1) children's prosocial behaviors were significantly different by sex, state empathy, and social evaluation, and (2) children's prosocial behaviors were not significantly different by their trait empathy level.

• Journal of the Korean Institute of Educational Facilities
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• v.20 no.3
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• pp.41-52
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• 2013

In the current condition of seeking eco-friendly development, Green Building Certification Criteria can reduce environment burden that is able to be arose in life cycles of buildings. Moreover, it is a great help to induce to constructing pleasant environment. The ripple effect that also improves saving of energy and resources of the whole country, and green-house gases reduction effect and environment friendliness of other buildings can be expected by promoting eco-friendly education facilities which accounts for a great part of public buildings in comparison with other buildings. In this study, analysis of old and new indicators' contrast and contents in Green Building Certification, and post evaluation of education facilities and interviews on authorities were proceeded for improving evaluation indicator of each item in Green Building Certification Criteria. As a result, it analyzed problems in terms of institution and operations management, and drew implications accordingly. In addition, it has a significance in that it proposes improvements of substantively applicable indicators with high applicability.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.179-189
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• 2017

This paper is the fifth investigation on the methods of evaluating flow characteristics in a steady flow bench. In previous studies, several assumptions used in the steady flow bench were examined and it was concluded that the assumption of the solid rotation may lead to serious problems. In addition, though the velocity profiles were improved as the measuring position went downstream, the distributions were far from ideal regardless of the valve angle and evaluation position. The eccentricities were also not sufficiently small to disregard the effect on impulse swirl meter (ISM) measurement. Therefore, the effect of these distribution and eccentricity changes according to the positions needs to be analyzed to discuss the method of flow characteristics estimation. In this context, the effects of evaluation position on the steady flow characteristics were studied. For this purpose, the swirl coefficient and swirl ratio were assessed and compared via measurement of the conventional ISM and calculation based on the velocity by particle image velocimetry(PIV) from 1.75B, 1.75 times bore position apart from the cylinder head, to the 6.00B position. The results show that the swirl coefficients by ISM strictly decrease and the curves as a function of the valve lift become smooth and linear as the measuring position goes downstream. However, the values through the calculation based on the PIV are higher at the farther position due to the approach of the tangential velocity profile to ideal. In addition, there exists an offset effect between the velocity distribution and eccentricity in the low valve lift range when the coefficients are estimated based on the swirl center. Finally, the curve of the swirl ratio by ISM and by PIV evaluation as a function the measuring position intersect around 5.00B plane except at $26^{\circ}$ valve angle.

• Journal of the Korean Society of Food Culture
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• v.22 no.4
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• pp.383-392
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• 2007

The object of this study is to evaluate the Korean traditional food culture education program which was developed in the prior study. In order to evaluate the effect of the program on the students’ knowledge of traditional food culture and their food habit, the program was practiced for 82 students in 4 elementary schools located in Seoul and Kyungki province during 16 weeks from Mar 1, 2005 to July 23, 2005. The pretest and the post-test were performed using an evaluation tool which is composed of evaluation sections for the perception and knowledge of the Korean traditional food culture, Korean children’s food habit and food preference for the Korean traditional food and fast food. The validity of evaluation was proved through the control group in the pretest and the post-test. Descriptive analysis and paired t-test were performed using SPSS/WIN 12.0 Statistic Package in order to compare the results of the pretest with those of the post-test after the education. The perception of the students who took the class for the Korean traditional food was slightly improved (p<0.05) and their knowledge was also increased (p<0.001) after the education while no difference was found in the control group. Moreover, the subjects’ food habit (p<0.001) and their preference of the Korean traditional food (p<.05) were increased respectively but their preference of the Western fast food was decreased(p<.01). These results indicate that the education program evaluated in this study has the effect of altering the subjects’ food habit or food preference as well as of introducing the knowledge of the Korean traditional food culture.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.743-751
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• 2010

It requires an interim performance assessment for BTL business of the sewerage rehabilitation which continues from 2005 till now. Means, It is necessary to make an interim performance assessment and an analysis of an business effect of the sewerage rehabilitation BTL projects which still continues, and we presented an improvement method of the new sewerage rehabilitation project in future. This paper has conducted an analysis of the business effect for 3 local government BTL projects which are completed and under operation as of now in Jincheon-Gun, Cheongju-Si and Gangjin-Gun. As a method of business effect analysis, we conducted a business effect of the 3 places using the index set which we previously set for the business effect analysis. The index set in this research was sectionalized to an improvement effect of operating wastewater treatment plant, an benefit effect of the direct cost, an benefit effect of the indirect cost and an environment friendly effect. We, in this paper, conducted an business effect analysis for 3 sewerage rehabilitation BTL projects which are completed or under operation recently as a demonstration, however we judge that an business effect analysis shall be conducted in a stage that a significant time for operation has passed since the completion of the construction in order to induce an actual business effect of the sewerage rehabilitation BTL project.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.2
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• pp.163-175
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• 2007

[ $ulcorner$ ]Cost-Effectiveness Analysis$\lrcorner$ has been wifely used to evaluate economic efficiency of R&D projects, but most of cost-effectiveness evaluation systems have some problems such as systematic method for setting and evaluating cost factors, estimation of single effect on each R&D project, and estimation of cross effects among R&D projects. To solve these problems, we have designed a new evaluation indicator called a $ulcorner$Cost-Cross Effect Integration Indicator$lrcorner$ including cross effects developed in this research. The major research findings are summarized as follows : (1) $ulcorner$Coist Estimation Model$lrcorner$, which estimates the cost factors divided into two classes of assembly product and system product and then integrates the total cost values, has been designed. (2) A new method for estimating parameters of cross effects among R&D projects has been developed. (3) $ulcorner$Cross Effects Estimation Model$lrcorner$ to estimate multi-effects and cross effects by completion time among several projects has been designed. (4) $ulcorner$Integration Estimation Indicator$lrcorner$ for setting priority on a project group has been extracted by combination of total cost value and total effect value.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.125-132
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• 2007

In order to provide consumers with safety informations of vehicles according to the Korean New Car Assessment Program(KNCAP), the evaluation results and the star ratings of 21 vehicles for the side impact tests have been reported since 2003. Now, the KNCAP considers changing the side impact dummy from EuroSID-1 to EuroSID-2 near future. The rib deflection of EuroSID-2 is 20-30% higher than that of EuroSID-1 because of the removal of "Flat Tops" effect. In this study, the effect of changing the side impact dummy from EuroSID-1 to EuroSID-2 in the KNCAP side impact evaluation is estimated through the previous KNCAP evaluation results. The results show that the decrease of the star ratings would be one star($\bigstar$) approximately.