• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.56-63
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• 2016

We consider a satellite mission scheduling problem, which is a promising problem in recent satellite industry. This problem has various considerations such as customer importance, due date, limited capacity of energy and memory, distance of the location of each mission, etc. Also we consider the objective of each satellite such as general purpose satellite, strategic mission and commercial satellite. And this problem can be modelled as a general knapsack problem, which is famous NP-hard problem, if the objective is defined as to maximize the total mission score performed. To solve this kind of problem, heuristic algorithm such as taboo and genetic algorithm are applied and their performance are acceptable in some extent. To propose more efficient algorithm than previous research, we applied a particle swarm optimization algorithm, which is the most promising method in optimization problem recently in this research. Owing to limitation of current study in obtaining real information and several assumptions, we generated 200 satellite missions with required information for each mission. Based on generated information, we compared the results by our approach algorithm with those of CPLEX. This comparison shows that our proposed approach give us almost accurate results as just less than 3% error rate, and computation time is just a little to be applied to real problem. Also this algorithm has enough scalability by innate characteristic of PSO. We also applied it to mission scheduling problem of various class of satellite. The results are quite reasonable enough to conclude that our proposed algorithm may work in satellite mission scheduling problem.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.2 s.245
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• pp.202-209
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• 2006

As the economic power is improved and the customer's demand is hard to please, the noise and vibration is the most important yardstick that can determine the quality of the product. Especially, as the airconditioner's demand increase suddenly, the product of quality and the noise is becoming a decisive factor of determining whether purchase the product or not. Therefore, every manufactory is investing a lot of money and research to cut down the unpleasantness induced from noise and vibration. And they are emphasizing their product's difference by advertising a silence very actively. With these reason, the demand of a silent indoor air-conditioner is the essential research filed when the product is develop(:d. In this study, the noise and vibration is visualized in the space and frequency domain by using experimental methods such as operational deflection shape (ODS), modal testing and sound intensity. Also the location of noise source and its characteristic is analyzed in an acoustical point of view to reduce the structure borne noise that come from the fan motor, and the pertinent control method is suggested. Furthermore, the most suitable shape of the motor bracket is suggested by applying FEM and DOE (Design of experiments) in the noise and vibration point a view.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.2
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• pp.89-111
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• 2012

Coalition loyalty programs, loyalty cash-back programs that enable their members to accrue and redeem points at a wide-range of affiliated outlets, are emerging. In a coalition loyalty program, unlike in a single-brand loyalty program, points accrued from one outlet can be redeemed in other outlets which even may be of other brands than the very one where the points were from. However, in spite of such systematic characteristic of coalition loyalty programs, there is only little research on the effect of the program. The present study is aimed at examining the difference between the effects of a coalition and a single-brand loyalty program in terms of acquisition and retention of customers and tries to provide strategic implications for a firm to run a loyalty program. We classify purchase conditions into two types-acquisition vs. retention. Then we compare the effects of a coalition and a single-brand loyalty program on the purchase intention, under both the acquisition and the retention conditions. The result shows that the effect of the coalition loyalty program is stronger than that of the single-brand loyalty program under the acquisition condition. On the other hands, the single-brand loyalty program is more effective than the coalition loyalty program under the retention condition, at least for the minor brand.

• Imaging Science in Dentistry
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• v.34 no.4
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• pp.175-178
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• 2004

Purpose: Picture Archiving and Communication System (PACS) is difficult to implement in the best of situations, but evidence is growing that the benefits are significant. The aims of this study are to analyze the current status of full PACS and establish successful installation standard of dental PACS. Materials and Methods : Materials and methods were based on the investigation of current working status and installation standard of PACS, and observation of variable issues to installation of dental PACS. Results: By September 30,2004, full PACS implementations in their facilities were 88.1 % in specialized general hospitals (37 installations out of total 42 hospitals), 59.8% in general hospitals (144 installations out of total 241 hospitals), 12.3% in medical hospitals (116 installations out of total 941 hospitals) and 3.6% in dental hospitals (4 installations out of total 11 0 hospitals) Only 4 university dental hospitals currently have installed and are operating full PACS. Major obstacle to wide spread of dental PACS is initial high investments. Conclusions: Clinical environments of dental PACS differed from medical situation. Because of characteristic dental practice, the initial investments for dental PACS are generally much greater than those of medical PACS. Also new economic crisis makes users scruple. The best way to overcome these limitations is to establish an economic installation standard for dental PACS. Also the clear technical communication between the customer and the supplier before both sides are committed to the obstacles are critical to its success.

• The KIPS Transactions:PartD
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• v.9D no.6
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• pp.1009-1016
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• 2002

We design and implement a new case-based recommender system using implicit rating information for a digital content site. Our system consists of the User Profile Generation module, the Similarity Evaluation and Recommendation module, and the Personalized Mailing module. In the User Profile Generation Module, we define intra-attribute and inter-attribute weight deriver from own's past interests of a user stored in the access logs to extract individual preferences for a content. A new similarity function is presented in the Similarity Evaluation and Recommendation Module to estimate similarities between new items set and the user profile. The Personalized Mailing Module sends individual recommended mails that are transformed into platform-independent XML document format to users. To verify the efficiency of our system, we have performed experimental comparisons between the proposed model and the collaborative filtering technique by mean absolute error (MAE) and receiver operating characteristic (ROC) values. The results show that the proposed model is more efficient than the traditional collaborative filtering technique.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.5
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• pp.933-944
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• 2001

The purpose of this research was to classify service dimensions for each apparel product which was thought to be important to consumers and to examine what kind of service dimensions are assessed to be more important than others. Furthermore, whether there were significant differences in the service dimensions and importances of services dimensions were examined by apparel product type(casual, formal products). Data were collected from women who were over 20 years old that live in Seoul. A questionnaire developed based on the previous researches and data were analyzed by factor analysis, t-test, ANOVA, frequency analysis. The results of this study were as follows: First, services of salesperson were divided into six dimensions: \"focused on customers\", \"knowledge/competency\", \"courtesy\", \"appearance/image\", \"purchasing induction\", and \"concerning\". As to service dimension importance, consumers think that \"service focused on customers\" is the most important dimension of service. Second, results of examining the importance according to apparel product type showed that five of the six service dimensions in formal product sales were more important except for the \"knowledge\" related service. Last, as to demographic characteristic variables, people who were over 40 years old were likely to think \"purchasing induction\", \"appearance/image\", \"concerning\" service dimensions more important than the other ages. And it was found that consumers who spend less money on purchasing clothing in a month thought \"focused on customers\" service was more important than the other consumers. In conclusion store managers could apply these results to service education of salesperson and use on preservation and improvement of customer relationship. And according to apparel product types, the results will give some implications to various service policies.

• Korean Management Science Review
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• v.32 no.2
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• pp.91-109
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• 2015

The M&A of firms has been emerged as the effective means of fast diversification and growth in dynamic environment. However, the empirical research about M&A in Korea has not been implemented rich due to the difficulty of obtaining M&A data. In this research, we empirically investigate the relationships among M&A, environment and firms' performance focused on Korean manufacturing firms, understanding the current practice of M&A in Korea. We use the Manufacturing Productivity Panel Survey Data, which are collected by Korea Productivity Center in 2013. The sample size is 575 and the sample is divided into M&A group and non-M&A group. We conduct logit analysis with the independent variables of environment factors (munificence, dynamic, uncertainty), and firms' performance (sales growth, ROS, labor productivity and Inventory turnover), and dependent variable of M&A group or non M&A group. The results show that M&A is closely related to environment feature and firm performance: M&A firms are likely to be the higher munificence and dynamic and the lower sales growth and higher profitability than non-M&A group. In addition, we also examine the characteristics of firms by M&A types (competitors, customer/supplier and firms from unrelated industry). These results imply that if firms confront the pressure of uncertainty (dynamic) and the lower growth, they tend to choose M&A. Futhermore, to profoundly understand the behavior of firms about M&A, it is required to classify the M&A firms by merge types.

• Fashion & Textile Research Journal
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• v.12 no.5
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• pp.574-581
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• 2010

Trunks like men's underpants are similar to boxer shorts and are made in both modern and traditional styles. Like boxer shorts, trunks cover the mid-section of the body (hence the name "trunk"). As the income level of the nation increases, men as well as women become interested in fashion expressing the individual's character, by not regarding fashion as simply wearing essential items to live in. Men's interest in fashion influences men's underwear designs which has been thought previously just as to be worn for living in. Nowadays, trunks are often worn as lounge wear in the household, therefore the need for sensual and characteristic trunks designs is required in the fashion market to meet the customer's new needs. In modern fashion designs, Chinese letters have been artistically presented and used in decorative fashion design regardless of its original meaning, generally embroidered in traditional costumes. Based on the fact that Chinese letters containing lucky meanings have traditionally been used, other Chinese letters meaning positive and prospective future can be adapted and weaved into men's trunks designs. Therefore, in this study, among many good meaning Chinese letters; four Chinese letters, 高(high), 金(gold), 義(justice), 愛(love), have been selected and applied in the trunks designs. The purpose of this study is to develop men's trunk designs using these Chinese letters which can be massively produced and sold in Asian countries which commonly understand the meaning of the Chinese letters as well as in South Korea.

• Health Policy and Management
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• v.24 no.3
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• pp.254-260
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• 2014

Background: The purpose of this study is to assume appropriate outpatient consultation time for each clinical department on the basis of measured outpatient consultation time and satisfaction of outpatient. Methods: We surveyed the feeling and satisfactory outpatient consultation time, satisfaction, revisiting intention and recommendation to others to 1,105 patients of single general hospital in Gyeonggi-do and measured their real outpatient consultation time from October 28 to November 27 in 2013. On the basis of satisfaction, we estimated appropriate outpatient consultation time through area under the receiver operating characteristic curve in logistic regression model. Results: Feeling outpatient consultation time was 5.1 minutess, satisfactory outpatient consultation time which was suggested by patient was 6.3 minutes, and real outpatient consultation time was 4.2 minutes. Department which had longest real outpatient consultation time was infection (7 minutes) and department which had longest satisfactory outpatient consultation time was neurology (9.4 minutes). From the univariate and the multiple linear regression analysis, real outpatient consultation time was longer in pulmonology patient, new patient and afternoon patient, satisfactory outpatient consultation time was longer in infection, neurology, neuropsychiatry, neurosurgery, and rehabilitation patient. Appropriate real outpatient consultation time was suggested as 5.6 minutes which differentiated high and low satisfied patient group. However, we could not assume appropriate outpatient consultation time for each clinical department because the number of patient who had bad satisfaction was too low. Conclusion: To improve patient's satisfaction, we hope outpatient reservation system is operated as each patient's outpatient consultation time is at least 5.6 minutes.

• Korean journal of food and cookery science
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• v.29 no.2
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• pp.169-175
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• 2013

The purpose of this study was to provide the basic information necessary to efficiently run a coffee shop. It comparatively analyzes the relative importance and satisfaction of side menu selection characteristics through analyses on customer importance-satisfaction when selecting a side menu as well as their usage behavior of the side menu at coffee shops. According to reason price the analysis result on the differences in the coffee shop side menu importance and satisfaction, there was a difference because the importance of selecting a side menu was higher for the attributes of taste, health, packing & appearance, economics and personnel service compared to satisfaction among which the price of a side menu was found to be the top priority for improvement. The significance of coffee shop side menu for the respondents prior to usage as well as their satisfaction after usage was evaluated in order to comparatively analyze the relative importance and achievement of each characteristic through the IPA. The result indicated that the variables positioned in the Concentrate Here area (II) were related to economic feasibility such as reasonable price, appropriate price of set menu, telecommunication company affiliated service and coupon usage and point accumulation. As for the Keep up the Good Work area (I), there were many variables regarding personnel service including taste of side menu, blending with coffee, clean packing, clean packaging, staff's side menu knowledge, staff's quick response, staff's politeness and staff's sincere response. As for the variables in the Low Priority area (III), health variables on health such as nutritional value, eco-friendly food materials and calories were observed.