• Title/Summary/Keyword: Cha-cheon

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The Software Verification and Validation Tasks for a Safety Critical System in Nuclear Power Plants

  • Cheon Se Woo;Cha Kyung Ho;Kwon Kee Choon
    • International Journal of Safety
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    • v.3 no.1
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    • pp.38-46
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    • 2004
  • This paper introduces the software life-cycle V&V (verification and validation) tasks for the KNICS (Korea nuclear instrumentation and control system) project. The objectives of the V&V tasks are mainly to develop a programmable logic controller (PLC) for safety critical instrumentation and control (I&C) systems, and then to apply the PLC to developing the prototype of an engineered safety features-component control system (ESF-CCS) in nuclear power plants. As preparative works for the software V&V, various kinds of software plans and V&V task procedures have been developed according to the software life-cycle management. A number of software V&V tools have been adopted or developed to efficiently support the V&V tasks. The V&V techniques employed in this work include a checklist-based review and inspection, a requirement traceability analysis, formal verification, and life-cycle based software testing.

Synthesis of Aesculetin and Aesculin Glycosides Using Engineered Escherichia coli Expressing Neisseria polysaccharea Amylosucrase

  • Park, Soyoon;Moon, Keumok;Park, Cheon-Seok;Jung, Dong-Hyun;Cha, Jaeho
    • Journal of Microbiology and Biotechnology
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    • v.28 no.4
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    • pp.566-570
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    • 2018
  • Because glycosylation of aesculetin and its 6-glucoside, aesculin, enhances their biological activities and physicochemical properties, whole-cell biotransformation and enzymatic synthesis methodologies using Neisseria polysaccharea amylosucrase were compared to determine the optimal production method for glycoside derivatives. High-performance liquid chromatography analysis of reaction products revealed two glycosylated products (AGG1 and AGG2) when aesculin was used as an acceptor, and three products (AG1, AG2, and AG3) when using aesculetin. The whole-cell biotransformation production yields of the major transfer products for each acceptor (AGG1 and AG1) were 85% and 25%, respectively, compared with 68% and 14% for enzymatic synthesis. These results indicate that whole-cell biotransformation is more efficient than enzymatic synthesis for the production of glycoside derivatives.

An intelligent consultant for material handling euqipment selection and evaluation

  • Park, Yang-Byung;Cha, Kyung-Cheon
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1995.04a
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    • pp.79-90
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    • 1995
  • The material handling equipment selection, that is a key task in the material handling system design, is a complex, difficult task, and requires a massive technical knowledge and systematic analysis. It is invaluable to justify the selected equipment model by the performance evaluation before its actual implementation. This paper presents an intelligent knowledge-based expert system called "IMESE" created by authors, for the selection and evaluation of material handling equipment model suitable for movement and storage of materials in a manufacturing facility. The IMESE is consisted of four modules: a knowledge base to select an appropriate equipment type, a multiple criteria decision making procedure to choose the most favorable commercial model of the selected equipment type, a database to store the list of commercial models of equipment types with their specifications, and simulators to evaluate the performance of the equipment model. The whole process of IMESE is executed under VP-Expert expert system environment.vironment.

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Adaptive Exponential Smoothing Method Based on Structural Change Statistics (구조변화 통계량을 이용한 적응적 지수평활법)

  • Kim, Jeong-Il;Park, Dae-Geun;Jeon, Deok-Bin;Cha, Gyeong-Cheon
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2006.11a
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    • pp.165-168
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    • 2006
  • Exponential smoothing methods do not adapt well to unexpected changes in underlying process. Over the past few decades a number of adaptive smoothing models have been proposed which allow for the continuous adjustment of the smoothing constant value in order to provide a much earlier detection of unexpected changes. However, most of previous studies presented ad hoc procedure of adaptive forecasting without any theoretical background. In this paper, we propose a detection-adaptation procedure applied to simple and Holt's linear method. We derive level and slope change detection statistics based on Bayesian statistical theory and present distribution of the statistics by simulation method. The proposed procedure is compared with previous adaptive forecasting models using simulated data and economic time series data.

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Chemical characteristics of $PM_{10}$ Concentration of suspended particles in Anmyon-do (안면도 부유부진 중 $PM_{10}$ 농도의 화학적 특성)

  • Kim, San;Shin, Do-Sik;Cha, Ju-Wan;Kim, Jung-Sik;Choi, Jae-Cheon
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 1999.10a
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    • pp.433-435
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    • 1999
  • 대기 중에 존재하는 에어로졸은 물리ㆍ화학적인 반응에 의하여 생성되며 금속, 수용성 성분을 비롯한 탄소입자 등으로 복잡하게 이루어져 있다. 이들은 대기중에서 시정감소와 광산란을 야기시킬 뿐 아니라 인체에 흡입되어 호흡기질환등을 야기 시킨다(Holt,1988). 또한 분진은 입자의 크기가 작을수록 상대적으로 표면적이 증가하여 각종 유해 대기오염물질과 흡착하여 인체에 악영향을 미친다(Simpson, 1992; John et al., 1990).(중략)

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Analysis for $CO_2$ concentrations of Anmyon Island using selecting scheme of background $CO_2$ concentrations at WDCGG (세계온실기체자료센터의 배경대기중 $CO_2$자료 선정방법에 따른 안면도 자료의 분석)

  • Kim, Jung-Sik;Shin, Do-Sik;Kim, San;Cha, Ju-Wan;Choi, Jae-Cheon;Park, Sang-Wook
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 1999.10a
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    • pp.269-271
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    • 1999
  • 온실기체농도에 대한 감시는 전세계적으로 미국의 NOAA(National Oceanic and Atmospheric Administration)/CMDL(Climate Monitoring and Diagnostic Laboratories)의 관측망을 비롯하여 세계기상기구(WMO)의 지구대기감시(GAW)계획에 의하여 수행되고 있다(Keeling et al., 1976 ; Komhyr et al., 1989). 기상청에서는 온실기체의 관측을 위하여 1994년에 전남 무안의 무안기상대에 비분산적외선 이와 같이 측정된 $CO_2$농도자료가 배경대기관측자료로써의 신뢰를 받기 위해서는 적절한 질관리를 통하여 인간 및 생물의 활동에 의한 직접적인 영향 제거하여야 한다.(중략)

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Inferiority, Depression and Psychosomatic Symptoms in Female Adolescents: The Mediating Effect of Perceived Entrapment (청소년 여학생의 열등감, 우울 및 정신신체 증상의 관계 - 지각된 속박감(perceived entrapment)의 매개효과 -)

  • Cheon, Suk-Hee;Cha, Bo-Kyoung
    • Child Health Nursing Research
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    • v.14 no.4
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    • pp.343-351
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    • 2008
  • Purpose: This descriptive correlation study was designed to examine the relationship of inferiority to depression and psychosomatic symptoms in female adolescents. In addition, this study investigated the mediating effect of perceived entrapment in relation to inferiority and other variables. Method: Data were collected from 526 female high school students. Self-report questionnaires, which were constructed to include demographic factors, inferiority, perceived entrapment, depression and psychosomatic symptoms, were used for data collection. Results: Students with high inferiority showed significantly higher perceived entrapment, depression and psychosomatic symptoms. here were significant positive correlations among the variables. Perceived entrapment had a significant mediating effect in relation to inferiority, depression and psychosomatic symptoms. Conclusion: Further study is necessary to develop effective nursing interventions for managing inferiority and perceived entrapment in this population.

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Field Application of the Concrete Combined Coarse Particle Cement and Fly-ash (굵은 입자 시멘트 및 플라이 애시를 복합 사용한 콘크리트의 현장 적용)

  • Lee, Chung-Sub;Jang, Duk-Bae;Cha, Wan-Ho;Kwon, O-Bong;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.329-330
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    • 2009
  • This study is to investigate the effect of the combined use of fly ash(FA) and coarse particle cement(CC) collected in particle classification process of ordinary Portland cement(OPC) manufacturing on the hydration exothermic and strength development in the field application.

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Disinfection of Seawater by a $TiO_2$ Photocatalyst ($TiO_2$ 광촉매의 해수살균)

  • Park, Dae-Won;Kim, Il-Kwon;Cha, Sang-Wook;Choi, Yong-Ki;Kil, Gyung-Suk;Cheon, Sang-Gyu
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2011.06a
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    • pp.189-189
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    • 2011
  • 본 논문에서는 에너지 절감형 선박평형수 처리시스템 개발을 위하여, 저압 자외선 램프의 살균효율의 증대를 위한 광촉매 처리방법에 대하여 기술하였다. $TiO_2$ 광촉매를 석영관 주위에 감싸는 방법으로 살균챔버 내부에 설치하고 253.7 nm파장의 자외선과 광촉매에 의한 해수내 미생물 살균효과를 분석하였다.

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A Study on Surface Integrity in Ground Layers (연삭 가공면의 표면성상에 관한 연구)

  • Kim, Gyung-Nyun;Cheong, Chae-Cheon;Cha, Il-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.8 no.4
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    • pp.64-75
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    • 1991
  • The design of structures of modern industry has developed to satisfy stringent service, realiability and safety. Up to now, geometric profile which means surface foughness and dimension accuracy is mainly treated in manufacturing process of work surface. But it is inevitable to evaluate changes of surface geometry as well as the nature of alterations in surface layers because surface of workpiece changes as a result of phase transformation, chemical changes, plastic deformation and stress changes. This paper is to present principal data for safety design by verifying the effect of grinding conditions and method in grinding layers and to explain the method of measuring surface integrity. In this paper, structural steel(SM20C) is used as a workpiece. Of integrity, surface roughness in view of surface texture is analyzed by frequency domain and residual stress, structures and defect of ground layers in view of surface metallurgy are investigated.

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