• ETRI Journal
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• v.30 no.1
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• pp.81-88
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• 2008

The security threat posed by worms has steadily increased in recent years. This paper discusses the application of the optimal and sub-optimal Internet worm control via Pontryagin's maximum principle. To this end, a control variable representing the optimal treatment strategy for infectious hosts is introduced into the two-factor worm model. The numerical optimal control laws are implemented by the multiple shooting method and the sub-optimal solution is computed using genetic algorithms. Simulation results demonstrate the effectiveness of the proposed optimal and sub-optimal strategies. It also provides a theoretical interpretation of the practical experience that the maximum implementation of treatment in the early stage is critically important in controlling outbreaks of Internet worms. Furthermore, our results show that the proposed sub-optimal control can lead to performance close to the optimal control, but with much simpler strategies for long periods of time in practical use.

• Journal of the military operations research society of Korea
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• v.9 no.2
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• pp.61-68
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• 1983

The traditional theories of games are based on an assumption that the payoffs have a single dimension. In reality, any alternative is likely to imply more than one payoff. This paper deals with the game against nature with vector payoffs. The purpose of this paper is to develop methods for finding the practical optimal strategy in the game against nature with vector payoffs. Under the assumption that a prior probability over the stats of nature is given, this paper shows that a practical optimal strategy in this game can be obtained by applying a entropy method in order to assess the payoff weight and by employing the concept of compromise solutions in order to reduce the non-dominated solutions. When subjective payoff weights are unknown as well as known, these methods can be used. A numerical example is given.

• Journal of Korean Home Economics Education Association
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• v.9 no.2
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• pp.17-30
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• 1997

Purpose of this study is to analyze the validity of textbook content on practical arts for the 6th curriculum, to grasp the content problems and to propose the strategy of reformation to be satisfied with consumer better than supplier. The data collected from 196 elemantary school teachers who lived in Gyungsang-namdo and analized by SPSS/PC(sup)+ package program. The statistical methods used for analysis were frequency, descriptives, validity, t-test, oneway ANOVA. The major findings can be summarised as follows： 1. The textbooks on practical arts for 3rd, 4th, 5th and 6th grades showed unbalanced division for picture, figure, table unite and evaluation type of all units doesn’t show diversity. 2. The validity of textbook contents on practical arts was found to be the highest for 3rd grade textbook and the lowest for 6th grade one. Among the validity of the evaluation items,‘differentiation with other subject’and ‘usefulness of living’showed high scores, wheres ‘fitness of child level’marked lowest score. 3. There was no significant difference Among the validity contents of teachers based on socio-demographic variables.

• Smart Media Journal
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• v.10 no.1
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• pp.55-62
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• 2021

We applied machine learning of semi-supervised learning, transfer learning, and federated learning as examples of AI use cases that can be applied to the three major industries(Automobile industry, Energy industry, and AI/Healthcare industry) of Gwangju Metro-city, and established an ML strategy for AI services for the major industries. Based on the ML strategy of AI service, practical approaches are suggested, the semi-supervised learning approach is used for automobile image recognition technology, and the transfer learning approach is used for diabetic retinopathy detection in the healthcare field. Finally, the case of the federated learning approach is to be used to predict electricity demand. These approaches were tested based on hardware such as single board computer Raspberry Pi, Jaetson Nano, and Intel i-7, and the validity of practical approaches was verified.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.293-293
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• 2006

Self-assembled nanostructures of block copolymer thin films have gathered significant attention due to their potential applications as templates for nanofabrication. However the lack of a robust strategy to control the structure formation in thin film geometries has been considered a major obstacle for the practical application. In this presentation 'epitaxial self-assembly' will be introduced as a successful strategy to control the self-assembled nanostructure of block copolymer. Chemically patterned surfaces prepared by advanced lithographic techniques successfully registered nanodomains in block copolymer thin film without any single defect over an arbitrarily large area.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1216-1222
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• 2005

A shortage of construction field workers has been a serious problem, both in the developed and in the developing countries. As a solution for conquering this problem, these countries import foreign laborers from nearby less-developed countries. While this contributes to lessening the labor deficiency, foreign workers are relatively inefficient in productivity and are often exposed to the cross-cultural risks due to cultural differences, communication difficulties, different work ethics and customs, etc. Despite these facts, construction firms do not well address these issues and are lagged in establishing an appropriate management strategy against it. This paper presents a practical management plan for foreign construction workers through Focus Group Interviews (FGI) and survey investigation. On this basis, this study examines the level of awareness and important managerial aspects of the issue of foreign laborers. Finally, it suggests a cross-cultural and ready-to-use practical human resource management plan for facilitating the foreign worker's productivity.

• Journal of the Korean Operations Research and Management Science Society
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• v.35 no.1
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• pp.67-81
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• 2010

In Schumpeterian competition, superior profit arises from successful innovation created by firm's R&D strategy. Such R&D strategy diverges as time passes. This study examines empirically the effects of diverged forms of R&D strategy such as technological assets, technological diversity, and technological similarity on firm performance in Korean pharmaceutical industry. With the financial and patent data of 96 firms for 14 years from 1994 to 2007, we measured variables. And then we performed panel analysis with 3 years lag between dependent variable and other variables. The result shows that firm performance increases as technological asset and technological diversification increase. But technological similarity positively affects on firm performance in opposition to our hypothesis. We interpret and discuss these results and highlight the theoretical and practical implications of our findings.

• Journal of Information Technology Services
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• v.16 no.3
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• pp.1-15
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• 2017

This study is aimed to find out which factors among firm-specific resources, industry-based competition, and institutional conditions affect strategies for Korean IT manufacturing companies when they expand their business overseas, especially to Vietnam in this study. Also, it attempts to reveal which strategies among cost reduction, mass production, and localization affect performance of overseas expansion. Based on Strategy Tripod Theory as an integrating point-of-view embracing resource-based view, industry-based view, and institution-based view, research model was developed and tested through the survey of 83 Korean IT manufacturing companies expanded their business to Vietnam. Research findings show that (1) communication competency, industry competitiveness, industry attractiveness, and regulation of partner country affect cost reduction strategy. (2) International experience, communication competency, international orientation, and competitiveness is significantly associated with mass production strategy. (3) And international experience, communication competency, and industry competitiveness affect localization. (4) Ultimately, mass production strategy and localization strategy significantly increase performance of expansion to Vietnam. The theoretical contribution of this study is to adopt an integrative approach based on strategy tripod theory. As practical implications, it suggests factors and strategies that IT manufacturing companies interested in expansion to Vietnam should consider. In sum, we believe this study can contribute to Korean IT manufacturing industry by suggesting key success factors and appropriate strategies for overseas expansion.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.147-154
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• 2000

This paper proposes an overmodulation strategy for space-vector PWM(SVPWM). The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation region. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. The practical implementation is simple and it is applied to improve an output voltage of SVPWM controlled AC Motor in the steady-state. The characteristic of the proposed strategy is confirmed by simulations and experiments for a V/F control of a induction motor.

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.34-36
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• 2005

To promote the mentality on intellectual property, this paper presents the concept and importance of intellectual property, international trend on patent policy and practical acquisition and maintenance strategy of patent for the domestic middle and small business enterprise and engineers.