• Journal of KIISE
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• v.42 no.12
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• pp.1495-1502
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• 2015

Data compression involves a trade-off between delay time and data size. Greater delay times require smaller data sizes and vice versa. There have been many studies performed in the field of wireless sensor networks on increasing network life cycle durations by reducing data size to minimize energy consumption; however, reductions in data size result in increases of delay time due to the added processing time required for data compression. Meanwhile, as energy generation occurs periodically in solar energy-based wireless sensor networks, redundant energy is often generated in amounts sufficient to run a node. In this study, this excess energy is used to reduce the delay time between nodes in a sensor network consisting of solar energy-based nodes. The energy threshold value is determined by a formula based on the residual energy and charging speed. Nodes with residual energy below the threshold transfer data compressed to reduce energy consumption, and nodes with residual energy above the threshold transfer data without compression to reduce the delay time between nodes. Simulation based performance verifications show that the technique proposed in this study exhibits optimal performance in terms of both energy and delay time compared with traditional methods.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.78-86
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• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.339-349
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• 2019

The purpose of this study is to analyze the influential factors on the change in life satisfaction of elderly households. In this study, single and couple elderly households were defined as elderly households and the 2nd, 3rd, and 4th data of the Korean Longitudinal Survey of Ageing (KLoSA) provided by the Korea Employment Information Service (KEIS) were used. And 677 respondents aged 65 and over who had replied to all 3 sessions were included in the final subjects. multinomial logistic regression analysis was conducted to examine the influential factors on life satisfaction by the type of elderly households according to consumption pattern and the result showed that there were common influential factors such as house owning status and subjective health status and the factors that influence specific types such as expectancy of standard of living. In addition, in the longitudinal analysis of life satisfaction of elderly households, individual satisfaction level was confirmed to reduce with time and the factors that influence the longitudinal change in the level of life satisfaction of elderly households was analyzed through the conditional model of a latent growth model. The analysis results showed that household type, house owning status, and subjective health status influenced the initial value of life satisfaction of elderly households while household type and expectancy of living standard influenced the change rate of life satisfaction of elderly households. Based on the results of this study, the followings are suggested. There is a need to improve the life satisfaction of old age by increasing the opportunity for self-realization of elderly households and also policy approach should be made selectively taking various types into consideration.

• Journal of Families and Better Life
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• v.23 no.4 s.76
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• pp.79-89
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• 2005

This study was conducted to encourage dissatisfied consumers to initiate an active complaining process over beauty salon services as well as to reduce consumer dissatisfaction at the time of using such services. A questionnaire survey was conducted with female consumers over the period between December 1 and December 20, 2004. A total of 753 questionnaires were used for the final analysis. The following findings were obtained: 1. Consumer dissatisfaction index with beauty salon services was 23.02 (65.77/100) and the respondents showed the highest level of dissatisfaction with the price. 2. The level of complaints about beauty salon services was very low, as shown by the index value 7.12 (25.43/100). Most of the respondents simply did not go back to the particular beauty shop, or complained privately to people around them when they felt dissatisfied with beauty service. 3. Benefit awareness and level of dissatisfaction had the greatest effect on the complaint behavior about unsatisfaction beauty salon services.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.281-286
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• 2011

Station structures, one of important infrastructures, which have been being operated since the 1970s, are especially vulnerable to even the medium-level earthquake and they could be damaged by long-term internal or external vibrations such as ambient vibrations. Recently, much attention has been paid to real-time monitoring of the fatal defect or long-term deterioration of civil infrastructures to ensure their safety and adequate performance throughout their life span. In this study, a structural health monitoring methodology using acceleration responses is proposed to evaluate the health-state of the station structures and to detect initial damage-stage. A damage index is developed using the acceleration data and it is applied to outlier analysis, one of unsupervised learning based pattern recognition methods. A threshold value for the outlier analysis is determined based on confidence level of the probabilistic distribution of the acceleration data. The probabilistic distribution is selected according to the feature of the collected data.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.73
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• pp.91-110
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• 2017

Recently, world wide trading which support free trade will increase the economic volume size. It will grow the quality of life. But, the reduce of gap between the rich state and the poor one has always been risen the problem of one of welfare. Trough unregulated trade activities, multinational corporations succeeded in expanding the market globally. However, there were unfair acts such as infringement of serious rights of producer of low development countries. Fair trade has begun to pay fair value to them and to ease inequality, but, as time went by, the its idea became thinner, distorted in the market, or became a marketing tools. So, In this paper, I analyze the limitations and causes of fair trade and suggest directions for fair trade. This Study provided a causes of the limitation of fair trade and for the future, I'll suggest an alternative of limitation of fair trade.

• Journal of the Korean Society of Systems Engineering
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• v.14 no.1
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• pp.44-51
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• 2018

The purpose of RAM analysis in weapon systems is to reduce life cycle costs, along with improving combat readiness by meeting RAM target value. We analyzed the sensitivity of the RAM analysis parameters to the use of the operating system by using the Markov Process based model (MPS, Markov Process Simulation) developed for RAM analysis. A Markov process-based RAM analysis model was developed to analyze the sensitivity of parameters (MTBF, MTTR and ALDT) to the utility of the 81mm mortar. The time required for the application to reach the steady state is about 15,000H, which is about 2 years, and the sensitivity of the parameter is highest for ALDT. In order to improve combat readiness, there is a need for continuous improvement in ALDT.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.44-47
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• 2004

Fabrication of barrier layer on PES substrate and plastic OLED device by atomic layer deposition are carried out. Simultaneous deposition of 30nm of $AlO_x$ film on both sides of PES gives film MOCON value of 0.0615g/$m^2$.day (@38$^{\circ}C$, 100% R.H). Introduction of conformal $AlO_x$ film by ALD resulted in enhanced barrier properties for inorganic double layered film including PECVO $SiN_x$. Preliminary life time to 91% of initial luminance (1300 cd/$m^2$ ) for 100nm of PECVD $SiN_x$/30nm of ALD $AlO_x$ coated plastic OLED device was 260 hours.

• The Research Journal of the Costume Culture
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• v.8 no.6
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• pp.949-963
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• 2000

Jambangee's advertisements in spring 1998 attracted public attention by the differentiating message of 'nationalism'. The purpose of this paper is to interpret Korean youth's culture of consumption, value, thought and culture expressed in these advertisements. The semiotic analytic method of F. Saussure and R. Barthe were used. Metaphor and metonymy as interpretive tools were used. Two levels of meaning, denotation and connotation were examined, and idelogies and mythologies were sought. Contrary to the most of jean advertisements which show youth, characteristic style, western life style and westernized beauty, refinement, materialism, and social differentiation, Jambangee's advertisement showed nationalism and patriotism. These advertisements criticized that preference of imported goods and ostentation of purchasing power brought crisis of economy and I.M.F. system. Jambangee's jeans symbolized as the meaning of nationalism and patriotism were suggested as a way to save our country. Jambangee's advertisements are meaningful. Because we had accepted western fashion passively so far, but for the first time Jambangee applied Korean design elements to jeans and gave new meanings to them through the 'nationalism'campaign.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.361-366
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• 2002

The deterioration of concrete structure due to corrosion of the reinforcement has created big financial losses on the overall industries. The volume expansion of the corrosion products causes internal pressure to concrete wall around reinforcing bar. If the maximum principal stress induced by internal pressure exceeds the tensile strength of the concrete at any point of time, a crack forms at any point of material. Therefore, in terms of life assessment of concrete structure, it is very important to predict the amount of corrosion products which induces initial concrete cracking. With this objective, this paper proposes the critical amount of corrosion products at interface between reinforcement and concrete using finite element analysis. If an actual survey of corrosion rates could be made, the model might supply information for condition assessment of existing concrete structure. As the mechanical properties of corrosion product and instantaneous geometry of corroded steel are considered in the analysis, the value obtained will be more realistic.