• IE interfaces
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• v.16 no.spc
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• pp.132-137
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• 2003

We consider scheduling jobs on multipurpose machines where jobs can be processed by a subset of the machines operated in parallel with the objective of minimizing makespan. We apply LPT(Longest Processing Time first) algorithm and prove that its posterior worst-case performance ratio is at most $log_24m/(1+{\lambda})$, where \lambda is the number of machines eligible for processing the job with the latest completion time. In general, LPT is shown to always find a schedule with makespan at most $log_24m/3$ times optimum.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.181-184
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• 2004

The objective of this experimental study is to grasp the effect of replacement level of high-quality recycled aggregate on the properties of high-performance concrete. The mixing types were divided into two series based on containing $0\%\;and\;15\%$ fly-ash. Replacement level of recycled aggregate ranged from $0\%\;to\;100\%$. Test results showed that the initial slump and the fluid velocity were independent on the replacement level of recycled aggregate, and the loss of compressive strength was almost $20\%$ with the recycled aggregate only.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.321-322
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• 2015

Thermoelectric power generation has emerged as a promising alternative technology because it offers a potential application in the direct conversion of waste heat into electric energy. The performance of thermoelectric power generator depends on thermoelectric materials and thermoelectric power module designs. The main objective of this study is to design a 100W thermoelectric generation (TEG) module and to get optimal operating conditions of the module. The design and performance of the TEG module will be presented.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.6
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• pp.1-14
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• 2007

Optimal design method of nonlinear damping system for seismic response control of adjacent structures is studied in this paper. The objective functions of the optimal design are defined by structural response and total amount of the dampers. In order to obtain a solution minimizing two mutually conflicting objective functions simultaneously, multi-objective optimization technique based on genetic algorithm is adopted. In addition, stochastic linearization method is embedded into the multi-objective framework to efficiently estimate the seismic responses of the adjacent structures interconnected by nonlinear hysteretic dampers without performing nonlinear time-history analyses. As a numerical example to demonstrate the effectiveness of the proposed technique, 20-story and 10-story buildings are considered and MR dampers of which hysteretic behaviors vary with the magnitude of the input voltage are considered as nonlinear hysteretic damper interconnecting two adjacent buildings. The proposed approach can provide the optimal number and capacities of the MR dampers, which turned out to be more economical than the uniform distribution system while maintaining similar control performance. The proposed damper system is verified to show more stable performance in terms of the pounding probability between two adjacent buildings. The applicability of the proposed method to the design problem for optimally placing semi-active control system is examined as well.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.186-193
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• 2000

In this study the effect and applicability of viscoelastic dampers on the seismic reinforcement of steel framed structures are investigated in the context of the performance based design approach. The effect of the damper on dissipating the input seismic energy was investigated with a single degree of freedom system. For analysis models a five-story steel frame subjected to gravity load and a ten-story structure subjected to gravity and wind load were designed. the code-specified design spectrums were constructed for each soil type and performance objective and artificial ground excitation records to be used in the nonlinear time history analysis were generated based on the design spectrums. Interstory drift was adopted as the primary performance criterion. According to the analysis results both model structures turned out to satisfy the life safety performance level for most of the soil conditions except for the soft soil. It was also found that the seismic performance could be greatly enhanced by installing viscoelastic dampers on appropriate locations.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.129-134
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• 2002

The seismic performance evaluation and retrofit process are very important for old bridge. If the result is not appropriate, a retrofit process requires. Among the various retrofit methods, this paper selects a seismic isolator and evaluates a seismic performance of bridge. In case of applied seismic isolators to bridge, it proved that seismic capacity is increased by isolators A period of bridge is increased, and a seismic response is decreased. A method of evaluation is capacity spectrum method. By means of a graphical procedure, capacity spectrum estimates a performance level of structure by comparing the capacity of structure with the demand of earthquake ground motion on the structure. The objective of this study is to compare a seismic performance of a non-seismic designed bridge and seismic isolated bridge and to verify a effect of seismic isolator

• International Commerce and Information Review
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• v.3 no.1
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• pp.177-196
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• 2001

The advancement of information technology provides a wide range of options for the corporate to cope with new business environments. As with most other businesses, the utilization of the logistics information technology can be an instrument to enhance the competitiveness of the company. Therefore it is essential to analyze how companies utilize and verify the relationship between company business performance and the level of information technology utilization, which is the objective of this paper. The questionnaire was sent to 300 companies listed on the stock market at random The author received 176 responses of which 142 were complete and valid. According to the analysis of questionnaires, the adoption level of information technologies was dependent on the perception of top managers on the importance of information technology in business competitiveness. Furthermore the level of relation between the information technology adoption and business performance was significant. Therefore businesses need to increase the utilization of information technologies, such as establishment of logistics information system, network with other business partners in order to business logistics performance.

• Journal of the Korea Fashion and Costume Design Association
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• v.4 no.1
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• pp.19-33
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• 2002

Consumer involvement is one of the most important concepts in target marketing. Marketing managers seeking repeat business and a long term relationship with their consumers must understand the process underlying product evaluation. Therefore, the objective of this study was to find out the relationships between consumer involvement and product performance. Judgement sampling method through survey was utilized to collect the data and the subjects were 614 university students. Factor analysis, reliability test, and regression were used to analyze the data. The research results showed that there were three dimensions of product performance, so called, ‘aesthetic’, ‘utilitarian’, and ‘socio-interactive’. Consumer involvement was positively related to all dimensions of product performance. Understanding of the relationship between consumer involvement and product performance would contribute to build useful marketing strategies.

• 한국경영정보학회:학술대회논문집
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• 2007.06a
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• pp.780-787
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• 2007

The Information and Communication Technologies (ICT) sector is undergoing a fundamental transformation. Determinant factors in this transformation process are deregulations and technological advancements. From the value chain perspective, industry convergence plays the most crucial role in the transformation of the established telecommunications and media industries. The objective of this paper is to validate the impact of convergence on the business performance using empirical data. To identify the various effects driven by industry convergence, we analyzed the relationships between firm's degree of convergence and the business performance using regression analysis. From the empirical result with the 2002-2005 data, it was found that the convergence across ICT sectors improves the business performance measured by Tobin's q significantly and this is only a recent phenomenon. These results are consistent with the conjecture that higher degree of convergence is becoming more associated with higher market value.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.1
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• pp.95-102
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• 2001

The design of automobile body assembly line is one of essential parts for improving the process performance. The major objective of this research is to develop a performance evaluation model for automobile assembly line using a closed queueing network(CQN) and simulation method. In this study we used a two-step approach to compute the performance of the assembly line : first, we used CQN model considering assembly line equipments and the line operating time under the assumption of no failure, and second we used a well-known simulator FACTOR/AIM. Finally we implemented this model on a K automobile company and we have shown the sample results of automobile body assembly line.