• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.1958-1968
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• 2015

In this paper, a new definition of short-circuit ratio concept for multi-converter HVDC systems is proposed. Analysis results of voltage interaction between converters show that the reactive power-voltage characteristic of a converter has a dominant effect on voltage interaction level compared with its active power-voltage characteristic. Such a relation between converter reactive power and voltage interaction level supports taking the former into account in the definition of short-circuit ratio concept for multi-converter systems. The proposed definition is verified by the method of maximum power curve for various system configurations. Furthermore, a formula to calculate transient overvoltage for multi-converter systems is derived based on the proposed definition, and the efficiency of the derived formula is verified.

• 기술혁신학회지
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• 제21권1호
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• pp.1-32
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• 2018

이 논문은 2017년 현재, 우리나라에서 과학기술정책학 또는 과학기술정책 연구가 독자적인 학문 정체성을 가지고 있는가 하는 문제의식에서 수행되었다. 이를 위하여 국내에서 출판된 과학기술정책 관련 단행본 19권을 대상으로, 학문 패러다임 형성의 핵심요소인 학문적 정의와 핵심 연구범위의 논의 여부를 분석하였다. 연구결과는 현 시점에서의 우리나라 과학기술정책학은 패러다임 형성 이전의 단계에 머물러 있다는 잠정 결론을 내렸다. 이러한 결론에 근거하여 연구자들은 향후 과학기술정책학의 패러다임 완성에 필요한 학문적 정의와 연구범위를 새롭게 제안하였다. 과학기술정책학은 '과학기술 활동 및 과학기술과 관련된 정치 경제 사회 문화의 제반 현상을 연구 분석함으로써, (1) 과학기술 자체의 발전을 도모하면서 (2) 과학기술을 활용하여 국가와 공공 부문의 문제해결 능력을 높이고자 하는 정책지향적인 학문'으로 정의하였다. 과학기술 정책학의 '연구범위'는 (1) 과학기술 정책과정, (2) 과학기술 공공관리, (3) 연구관리, (4) 기술혁신의 4대 부문으로 제안하였다. 이 중에서 '과학기술 정책과정'과 '과학기술 공공관리'는 이 논문에서 제안하는 과학기술 정책학의 정의를 반영하는 새로운 내용이며, '기술혁신'과 '연구관리'는 기존 연구들도 대부분 포함하고 있는 과학기술정책학의 연구범위라고 할 수 있다.

• 공학교육연구
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• 제13권4호
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• pp.43-50
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• 2010

이 연구의 목적은 STS(science-technology-society) 소양에 대한 대학생들의 관점을 알아보기 위한 것이다. STS 소양에 대한 견해는 과학과 기술의 정의, 과학 기술 사회의 상호 영향으로 범주를 나누었다. 연구대상은 서울과 제주 소재 3개 대학 공학계열 대학생(119명)과 사회계열 대학생(117명)이다. 연구 결과는 다음과 같다. 첫째, 과학과 기술의 정의에 대해 공학계열 대학생들은 생활의 편리성을 중시했고, 사회계열 대학생들은 현상을 설명하고 실험하는 것이라고 응답했다. 둘째, 두 집단은 과학-기술-사회의 상호관련성을 인식하고 있었다. 셋째, 두 집단은 과학기술자의 책임과 윤리, 기술의 이용 등에 대해 견해 차이를 보였다. 결론적으로 대학생들은 STS 소양과 관련해 높은 인식 수준을 나타냈다. 따라서 본 연구의 결과는 앞으로 대학 교육과정에서 STS 소양과 관련된 교과목을 개설하고 운영하는 데 있어서 중요한 시사점을 제공할 수 있을 것이다.

• 호남수학학술지
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• 제32권4호
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• pp.711-738
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• 2010

We list two kinds of gradation of openness and we study in the sense of the followings: (i) We give the definition of IVGO of fuzzy sets and obtain some basic results. (ii) We give the definition of interval-valued gradation of clopeness and obtain some properties. (iii) We give the definition of a subspace of an interval-valued smooth topological space and obtain some properties. (iv) We investigate some properties of gradation preserving (in short, IVGP) mappings.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.749-761
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• 2014

Improving spectrum utilization efficiency is a fundamental goal of dynamic spectrum access technology. The definition of spectrum holes determines how to detect and exploit them. Current definitions of spectrum holes are ineffective in exploiting spatial-temporal spectrum holes. In this paper, a novel definition of spectrum holes is proposed, in which throughput loss indicates the impact of secondary users on primary users. The definition specifies spectrum holes, unifies the impact of secondary users on primary users and is effective exploiting spatial-temporal spectrum holes. Theoretical analysis and numerical simulations show that the new definition proposed in this paper significantly improves the spectrum utilization efficiency.

• 대한인간공학회지
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• 제32권2호
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• pp.207-215
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• 2013

Objective: This study aimed to investigate important human factors that should be considered when developing ultra-high definition TVs by reviewing measurement methods and main characteristics of ultra-high definition displays. Background: Although much attention has been paid to high-definition displays, there have been few studies for systematically evaluating human factors. Method: In order to determine human factors to be considered in developing human-friendly displays, we reviewed subjective and objective measurement methods to figure out the current limitations and establish a guideline for developing human-centered ultra-high definition TVs. In doing so, pros and cons of both subjective and objective measurement methods for assessing humans factors were discussed and specific aspects of ultra-high definition displays were also investigated in the literature. Results: Hazardous effects such as visually-induced motion sickness, visual fatigue, and mental fatigue in the brain caused by undesirable TV viewing are induced by not only temporal decay of visual function but also cognitive load in processing sophisticated external information. There has been a growing evidence that individual differences in visual and cognitive ability to process external information can make contrary responses after exposing to the same viewing situation. A wide vision, ultra-high definition TVs provide, can has positive and negative influences on viewers depending on their individual characteristics. Conclusion: Integrated measurement methods capable of considering individual differences in human visual system are required to clearly determine potential effects of super-high vision displays with a wide view on humans. All of brainwaves, autonomic responses, eye functions, and psychological responses should be simultaneously examined and correlated. Application: The results obtained in this review are expected to be a guideline for determining optimized viewing factors of ultra-high definition displays and accelerating successful penetration of the next-generation displays into our daily life.

• 한국군사과학기술학회지
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• 제9권1호
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• pp.135-143
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• 2006

This paper describes a requirement architecture modeling for the front end of KT-1 export version requirement definition processes to construct SDS(system development specification). The requirement definition process is a highly conceptual process that is difficult to carry out. This paper focuses on how to perform the KT-1 export version requirements definition process including the integration of process, methods and tools for the front-end activity of requirements definition process. This requirement model is structured in four segments, including requirement layering, requirement categorization, life cycle stakeholder and requirement definition process using Computer-Aided Systems Engineering tool(CORE).

• 대기
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• 제23권1호
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• pp.63-71
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• 2013

KMA is operationally monitoring El Ni$\tilde{n}$o and La Ni$\tilde{n}$a events, which have tremendous impacts on global climate. Many scientific studies have used to define onset of El Ni$\tilde{n}$o and La Ni$\tilde{n}$a events based on the moving average and persistency of SST indices, and KMA has adopted such definition. Though the definition has been widely accepted, in the operational aspect there is a critical problem to use moving average and condition for the persistence. Because the future values for the SST indices cannot be used in the operational monitoring, the onset timing in El Ni$\tilde{n}$o and La Ni$\tilde{n}$a can be significantly delayed. We suggest here an appropriate definition of El Ni$\tilde{n}$o and La Ni$\tilde{n}$a events in the operational aspect. Instead of using the moving average and the condition for the persistence, the onset is defined based on NINO3.4 SST during last 3 months. In order to compare the new definition with the current KMA definition, we applied them to recent 60-years SST data. It is clear that the new definition can declare the onset timing of El Ni$\tilde{n}$o and La Ni$\tilde{n}$a several months earlier than that of the KMA definition. It suggest that the new definition is more appropriate to the operational monitoring on El Ni$\tilde{n}$o and La Ni$\tilde{n}$a.

• 식품과학과 산업
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• 제47권1호
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• pp.2-11
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• 2014

• 한국군사과학기술학회지
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• 제6권3호
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• pp.22-35
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• 2003

This paper describes system technical requirement development process from operational concept using computer-aided Systems Engineering tool(CASysE Tool-CORE). The army tactical missile system-ATACMS's technical requirements are developed by the process as a case-study The scope of the work is context analysis and requirement definition process. The proposed process is as follows. At first, an integrated architecture could be developed from the operational concept. From the integrated architecture a capability needs, which includes KPPs, are generated. And the capability needs expanded according to the Mil-Std-961D format. Lastly, a system technical requirement could be generated automatically from the CASysE Tool-CORE.