• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.971-982
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• 2015

In order to improve the quality of the billet continuous casting, a two-phase orthogonal power supply (TPOPS) for electromagnetic stirrer is researched, which is composed of three-phase PWM rectifier and three-leg inverter. According to the power analysis of system, the ripple of dc-link voltage is analyzed and its analytical expression is derived. In order to improve the performance of electromagnetic stirring, an integrated control method with feedforward control is proposed for PWM rectifier to suppress the fluctuations of dc-link voltage and provide a stable dc source for inverter. According to the simplified equivalent model, a composite current control method is proposed for inverter. This proposed method can combine the merits of feedforward control with feedback control to effectively improve the dynamic output performance of TPOPS. Finally, a 300kVA prototype of TPOPS is developed, and the results have verified the analysis and control method.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.685-688
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• 1998

In this research project, two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.365-368
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• 1998

In this research project two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

• Journal of Digital Convergence
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• v.6 no.3
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• pp.45-52
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• 2008

For the domestic digital contents, it is particularly important that the planning and mediating functions should cover the whole Industries so that dividends and assistance to reach all the way back to the primary contents-creating level, where economic risks are especially high. A proactive cooperation system or framework between the government, the businesses and research institutions, which would allow for free flow of interaction among these players, can play that role. We can broadly define cooperation frameworks into two; one between the central and the local governments and another among private-sector groups, such as companies, associations and groups. These players in the framework have differing, sometimes, conflicting views regarding the digital contents industry whether the digital contents should aim for skilled applicability or the abstract or whether the emphasis should rest on public interest or profitability. Immature competition and lack of trust among these players also give rise to such inefficiencies as overlap in investments, inexpertness and inefficient use of resources. We have proposed and realized the National Integrated Cooperation System to bridge these gaps among the major players in the industry. The National Integrated Cooperation System rests on the following major functions. The first major function of the NICS is to decipher any ambiguity that may be embedded in external Inputs by stratified role and bias. The second function is to create cooperative groups that will deal with the ambiguities based on its consequent situation. The third is a feedback function that will draw out a new cooperative way by re-feeding the capacities and the conflicts that stem from the existing organizations and strategies into cooperation and adjustment process. Our NICS has compared and evaluated with England and Australia digital content industry models under AHP(Analytic Hierarchy Process) method. NICS has turned out to be well designed and have strong points based on OECD innovation and cooperation criteria.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.58
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• pp.237-263
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• 2013

Traditionally, a L/C (letter of credit) has been known as a relatively low risk method of payment. This is why L/C has been used in international trade. However, L/C has a number of weak points such as high cost, long processing time, and complicated documents. Using an electronic L/C is one way to solve those weak points. In Korea, there are two types of electronic L/C. One is the EDI (Electronic Data Interchange) based L/C and the other one is the XML (Extensible Markup Language) based L/C. The former, established in 1990's, is sent from banks to the beneficiary solely through VAN (Value Added Network, KTNET) operators. On the other hand the latter, started in 2005, is sent from banks to KFTC (Korea Financial Telecommunications & Clearings Institute) for management of the L/C balance, as well as to KTNET. So far, paper L/C and EDI based L/C have been used overwhelmingly instead of XML based L/C in spite of the aforesaid disadvantages. In this paper, the authors examined empirically why the users of electronic L/C were reluctant to use XML based L/C. The results are as follows. First, the users of paper L/C were more dissatisfied than the users of electronic L/C due to many factors such as cost, the time required, and information reuse. Second, the users who have more experience with XML based L/C wanted to adopt integrated management with EDI based L/C more than the users who had not experienced XML based L/C. Third, the users who had used more than one form of L/C wanted to adopt integrated management to EDI and XML based L/C more than the users who had only used one form of L/C. Therefore, the authority for electronic L/C should consider a change of the policy from the XML based electronic L/C oriented to integrated management of the various types of L/C.

• Hwankyungkyoyuk
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• v.10 no.2
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• pp.249-268
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• 1997

This Study developed 'Environment Management Integrated Leader(EMIL)' program and evaluated the effect of the Program. The procedure of EMIL program development is as follows; 1) Identifying the training needs Through the interview and discussion with corporate environmental staff and research members, training need are collected. 2) Setting the training objectives 30 objectives are developed through specifying and organizing the training needs. 3) Determining the scopes of the program This program consists of the four scopes. First, the scope of Environmentally Acceptable Management is developed based on ISO 14000 and certification of environmentally friendly business. Second, the scope of Environmentally Acceptable Technology includes air pollution, water pollution, solid wasted management, and pollution prevention. Third, the scope of Integrated Environmental Management focuses on master plan, green marketing, green production, and green accounting. Finally, the scope of Integrated Environmental Concepts focuses on food pollution, environmental activities, and bio-diversity. 4) Selecting the training methods Various methods are used such as off-site visits, exercises, case study, workshop, discussion, role-playing as well as lecture. 5) Implementing the program 49 trainees participated the program for 6weeks. All trainees are working for D. Company Group. 6) Measuring training effects To evaluate the effects of the program, pre-post training evaluation method is used. The results are highly significant at all 4 scopes by the p<.01. This study has some implications in order to establish the environmental management climate. First, the development of new environmental education program for management is necessary. Second, Vast investment are required. Third, more systematic approaches are desired in environmental education. Lastly, more customized program development and implementation to fit in industries will accelerate the expansion of environmental concept.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.229-236
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• 2017

The Nursing Care Integrated Service is an inpatient service provided in a ward equipped with all kinds of professional nursing services, nursing environment improvement, and patient safety management through team nursing staff placement through appropriate nursing staff placement. The subjects of the study were 92 patients who agreed to understand and participate in the research purpose as the inpatient ward of a general hospital in Gyeonggi Province, for the study method, frequency, percentage, mean, standard deviation, t-test, ANOVA were applied using SPSS/WIN 21.0 program and the post test was Scheffe test. In addition, the correlation between nursing satisfaction and service evaluation was analyzed by Pearson's correlation. This paper is meaningful in that it reaffirms the importance of satisfaction and presents basic data for improving the quality of service of nursing care integrated service ward inpatients.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.8-17
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• 2022

This paper presents a novel geometric modeling technique to predict the mechanical properties of an aircraft wing's skin-stringer integrated panel. Due to mechanical and adhesive fastening, this panel is vulnerable to stress concentration and debonding, so we designed it to integrate the skin and stringer using three-dimensional woven composites. Geometric modeling was conducted by measuring the geometric parameters of the specimen and defining the pattern of the yarns as functions. We used a weighted average model with iso-strain and iso-stress assumptions to predict the mechanical properties of the panel parts. We then compared the results of a finite element analysis with a compression test to verify the accuracy of our model. Our proposed technique proved to be more efficient than the traditional experimental method for predicting the mechanical properties of skin-stringer integrated panels.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1093-1098
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• 2012

Commercial Off the Shelf(COTS) Integrated circuits(ICs) are being increasingly considered for use in space and military applications. Therefore, There is a need to implement standard tests and requirements to ensure reliability of COTS ICs. This paper presents an overview of the ICs screen procedure and methods under the European Cooperation for Space Standardization (ECSS) and Tests Method Standard Microcircuits (MIL-STD-883). We describes the COTS ICs screen test guidelines that are mainly focused after encapsulating. In addition, COTS linear bipolar IC is investigated to evaluate the reliability requirements. The experiment results showed that COTS IC is satisfied with high reliability requirements.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.3
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• pp.259-266
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• 2022

This study aims to introduce missile live-fire during the ship operational test and evaluation(T&E) as a means of verifying the integrated combat capability(ICC) of various systems installed on naval ships. The research method identified domestic and foreign T&E systems and cases, and reports related to ICC, which were written during the ship's design stage. As a result of research, Republic of Korea is not conducting the missile live-fire at the ship T&E stage due to the lack of relevant systems, while the U.S. is conducting it based on the mission-based T&E and the end-to-end test system. As a way to improve within the current domestic ship acquisition systems, the reaction time analysis, a quantitative analysis result of ICC calculated at the ship basic design stage, was proposed to be verified by missile live-fire during ship operational T&E.