• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.469-475
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• 1991

In this paper, we suggest the exact perturbation analysis(Exact_PA) technique with respect to the buffer storage in tandem queueing networks, through which the optimal buffer storage design problem is considered. The discrete event dynamic equations for the departure time of a customer are presented together with the basic properties of Full Out(FO) and No Input(NI) with respect to the buffer storage. The new perturbation rules with respect to the buffer storage are suggested, from which the exact perturbed path can be obtained. The optimal buffer storage problem is presented by introducing a performance measure consisting of the throughput and the buffer storage cost. An optimization algorithm maximizing this performance measure is derived by using the Exact_PA technique. The proposed perturbation analysis technique and the optimization algorithm are validated by numerical examples.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.167-184
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• 2013

A cross docking operation involves multiple inbound trucks that deliver items from suppliers to a distribution center and multiple outbound trucks that ship items from the distribution center to customers. Based on customer demands, an inbound truck may have its items transferred to multiple outbound trucks. Similarly, an outbound truck can receive its consignments from multiple inbound trucks. The objective of this study is to find the best truck spotting sequence for both inbound and outbound trucks in order to minimize total operation time of the cross docking system under the condition that multiple visits to the dock by a truck to unload or load its consignments is allowed. The allocations of the items from inbound trucks to outbound trucks are determined simultaneously with the spotting sequences of both the inbound and outbound trucks.

• Journal of the Korea Safety Management & Science
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• v.22 no.3
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• pp.9-14
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• 2020

A forklift accident occurs in the logisitcs center. there are many kinds of accidents such as a casualty accident or a minor accident, etc. there are many other causes of accident, including poor visibility and habitual operational mistakes The result of the accident is the phenomenon of cutting, falling, scratching of the product. In the case of minor accidents, workers do not report accidents, so the occurrence of accidents is unknown. The customer receives the goods and then notifies them that they are defective product. After the product is returned, we can see that the forklift accident caused the problem of the product The result of the late response affects the image of the enterprise. In this study, we recognized the need for safety education to prevent accidents and found out which of the education items could raise awareness of safety. As result of the study, disinfection and forklift maneuverability regarding speed were mentioned as the most important items in education.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.3 s.52
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• pp.213-218
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• 2005

Recently, with the remarkable increase in elderly persons and improvement of skin care technique, the requirements of customer for anti-aging care have become very important. Also, after cosmeceutical-product law was done in 2001, the major interesting field in cosmetic industry has been focused to developing anti-aging materials having safety and efficacy by basic science. In this review, we ill introduce the trend of anti-aging research and materials to prevent wrinkle or improve elasticity of skin.

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.281-287
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• 2012

The customer load profile clustering method is used to make the TDLP (Typical Daily Load Profile) to estimate the quarter hourly load profile of non-AMR (Automatic Meter Reading) customers. This study examines how the repeated clustering method improves the ability to discriminate among the TDLPs of each cluster. The k-means algorithm is a well-known clustering technology in data mining. Repeated clustering groups the cluster into sub-clusters with the k-means algorithm and chooses the sub-cluster that has the maximum average error and repeats clustering until the final cluster count is satisfied.

• Korean Institute of Interior Design Journal
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• no.37
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• pp.63-70
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• 2003

Housing market in korea has changed from seller's market to buyer's market since mid of 1990. The housing contractors also changed their conventional ideas and strategies of design of housing facilities in order to survive in the housing industry, They look for ways and means to better respond to client's needs and to better serve user's values. Recently customer relationship management(CRM) technique has been introduced in the housing business. CRM gives emphasis on ongoing relationship with customers. Housing cultural center is a place where customers and contractors can exchange informations. This study aims to extract design and operation issues of housing cultural center.

• Proceedings of the KIEE Conference
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• summer
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• pp.251-253
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• 2004

Nowadays, power customer has increased and new power plants have been constructed for market demands. However, increasement of power plants make power system more complex and unstable. For this reason, the stability problem is one of the most important issues in power systems. In this paper, a study on implementation of out-of-step detection algorithm is performed. The structure of digital relay is analyzed for development of out-of-step detection algorithm. DFT block which is used to extract basic frequency of voltage is analyzed to design VHDL.

• Journal of Industrial Convergence
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• v.15 no.1
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• pp.33-42
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• 2017

The purpose of this study is to identify the current situation of bicycle rental center in Seoul through big data analysis and to find ways to improve it. For this purpose, we analyzed the open data set provided by the Seoul Metropolitan Government and the typical data which is the citizen opinion of the customer center of the Seoul City bicycle. As the result, it was found that it is better to install a bicycle rental shop in Gangdong-gu, Seoul.

• Korean Journal of Community Nutrition
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• v.18 no.5
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• pp.491-504
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• 2013

The purposes of this study were to analyze the quality attributes, quality factors and customer satisfaction in school foodservice and to provide suggestions for improving school foodservice environments. The survey was distributed to different respondents (5,771 students, 2,045 parents, and 1,981 faculty members) at different types of schools (elementary school, middle school, and high school) on September 2010 in 16 cities and provinces. The data were analyzed using SPSS for descriptive analysis, one-way ANOVA, t-test and multiple linear regression analysis. First, all foodservice quality attributes were significant different by respondents and the faculty had higher scores than parents and students. A comparison of scores by respondents and distribution place demonstrated that classroom of student and parents had a higher score for quality attributes. The overall satisfaction with school foodservice was significant different by respondents and higher for classroom than for dining hall for student and parents. In comparison of annual data, there was decreased overall satisfaction and quality attributes in student and parents. Second, in the regression results, which showed the effects of the foodservice quality attributes on overall satisfaction by respondents and distribution place, improvements of 'food taste', 'pleasant foodservice environment', and 'kindness of employee' would increase satisfaction in most of the respondents. Third, the overall satisfaction with school foodservice was higher for nutrition teachers than dietitians for students and faculty. Therefore, the operators will need to make different efforts based on each customer needs to improve the overall satisfaction on school foodservice.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.203-209
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• 2014

The rear center-hinge bracket is designed for supporting and folding the rear-seat backrest. This bracket needs to be strong enough to be able to rigidly hold the rear-seat backrest and to withstand luggage loads from the car trunk that are generated when a vehicle is driving on the roads. Particularly, current accident studies report that many serious occupant injuries occurred when the rear-seat back easily folded inward toward the car interior, driven by the luggage loads in the trunk. Given this fact, the robust design of the rear center-hinge bracket that mainly supports the rear backrest has become more important for providing customer safety and preventing high warranty and durability problems. However, none of the studies have emphasized its significant role and considered its robust optimization. Therefore, this paper presents how the hinge-bracket design is optimized based on an application of the finite-element method coupled with the parameter design using Taguchi's design experiment. Finally, Taguchi method's application optimizes a robust center-hinge bracket that shows more rigid performance although it has lighter weight and thinner thickness.