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Identification of Correlative Transmission Lines for Stability Diagnosis of Power System (전력계통의 안정도 진단이 가능한 선로 선정에 관한 연구)

  • 조윤성;장길수;권세혁
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.5
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    • pp.271-278
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    • 2003
  • Power system stability is correlated with system structure, disturbances and operating conditions, and power flows on transmission lines are closely related with those conditions. This paper proposes a methodology to identify correlative power flows for power system transient and small-signal stability prediction. In transient stability sense, the Critical Clearing Time is used to select some dominant contingencies, and Transient Stability Prediction index is proposed for the quantitative comparison. For small-signal stability, this paper discusses a methodology to identify crucial transmission lines for stability Prediction by introducing a sensitivity factor based on eigenvalue sensitivity technique. On-line monitoring of the selected lines enables to predict system stability in real-time. Also, a Procedure to make a priority list of monitored transmission lines is proposed. The procedure is applied to a test system and the KEPCO systems in the year of 2003 and it shows capabilities of the proposed method

A Boolean Logic Extraction for Multiple-level Logic Optimization (다변수 출력 함수에서 공통 논리식 추출)

  • Kwon, Oh-Hyeong
    • Journal of the Korea Computer Industry Society
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    • v.7 no.5
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    • pp.473-480
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    • 2006
  • Extraction is tile most important step in global minimization. Its approache is to identify and extract subexpressions, which are multiple-cubes or single-cubes, common to two or more expressions which can be used to reduce the total number of literals in a Boolean network. Extraction is described as either algebraic or Boolean according to the trade-off between run-time and optimization. Boolean extraction is capable of providing better results, but difficulty in finding common Boolean divisors arises. In this paper, we present a new method for Boolean extraction to remove the difficulty. The key idea is to identify and extract two-cube Boolean subexpression pairs from each expression in a Boolean network. Experimental results show the improvements in the literal counts over the extraction in SIS for some benchmark circuits.

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Dynamic Characteristic Analysis and Transfer Function Estimate of Acoustic System for Transformer Noise Control (변압기 소음제어를 위한 음향 시스템의 동특성 해석 및 전달함수 추정)

  • 김영달;정창경;심재명
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.3
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    • pp.17-24
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    • 1999
  • This paper presents a method of ANC for transfonrer noise control utilizing a sproker and microphone pair. In this study, the main focus is on identifying the dynamic characteristics of speaker - amplifier microphone path. This study presents a theoretical method to identify the dynamic characteristics of speaker-microphone pairs. The transfer functions of microphone - speaker pair have been estimated utilizing sequential least square(SLS) algorithm. We identified the estimated transfer function has stable JXlles and zeros in z-plane. This paper also propose an architecture far the noise cancellation to which we applied the estimated transfer function.nction.

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Depression in Patients with Rheumatoid Arthritis (관절염 환자의 우울)

  • Kim, In-Ja
    • 대한근관절건강학회:학술대회논문집
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    • 1997.05a
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    • pp.134-146
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    • 1997
  • Sixty-nine articles were reviewed to understand the depression in patients with rheumatoid arthritis. Among these articles, forty seven were the studies that dealt with depression in rheumatoid disease, nineteen studied the depression in patients with other chronic disease or in normals, and three were the studies that compared the depression in the patients with rheumatic disease and in the other subjects. Specifically, the articles were analyzed (1) to determine whether the patients with rheumatic arthritis were more depressed than normal population or subjects with other chronic diseases ; (2) to test whether the measurement problems exit ; (3) to identify the disease related, personal, psychologic, and demographic variables to affect the depression and (4) to identify the nursing interventions which improve the depression in rheumatoid arthritis. Based upon these results, some suggestion were made for future research and practice.

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Development of a Standard to Assess Classifying Inquiry Skills by Observation (관찰에 의한 분류하기 탐구 능력 평가 준거 개발)

  • Ju, Jung-Eun;Cha, Hee-Young
    • Journal of Korean Elementary Science Education
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    • v.26 no.4
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    • pp.407-417
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    • 2007
  • The purpose of this research is to develop standards with which we can design an instrument to assess classifying inquiry skills by observing students' behavior and reported outcome which is not the paper and pencil test. This research is focused on developing a standard for analysis of classifying ability among research functions. To identify classifying inquiry skills, standards from classifying behaviors were comparing ways with other cards and using information included in the cards; Standards selected from the final reports were the appropriateness, inconsistency and hierarchy of the classification outcome. The standards were initially selected during the class with picture cards printed various birds appearances on the front side and their traits on the back which was specially designed among sixth graders. The picture cards prepared with plant leaves and stems had designed to identify whether standards was effective to assess student's classifying ability. The standards was an effective tool to assess student's classifying inquiry skills.

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Reducing the Rate of Defective to Improve a Welding Condition -Based on Six Sigma Process- (용접조건 개선으로 불량률 감소 -6시그마 프로세스를 중심으로-)

  • 박진영
    • Journal of Korean Society for Quality Management
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    • v.31 no.1
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    • pp.123-131
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    • 2003
  • This paper considers a six sigma project for reducing the defects rate of the welding process in manufacturing firms. The project follows a disciplined process of five macro phases. define, measure, analyze, improve and control(DMAIC). The need of customers is used to identify critical to quality(CTQ) of project. And a process map is used to identify process input factors of CTQ. Four key process input factors are selected by using an input factor evaluation of teams; an interval of welding, an abrasion, an electric current and a moving freely. DOE is utilized for finding the optimal process conditions of the three key process input factors. Another one key input factor improved to welding machine. The six sigma level of defects rate becomes a 2.01 from a 1.61 at the beginning of the project.

Factors Influencing Health Care Needs of Solitude Elderly (일 지역 독거 노인의 간호요구에 영향을 미치는 요인)

  • 이명숙
    • Journal of Korean Academy of Nursing
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    • v.33 no.6
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    • pp.812-819
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    • 2003
  • Purpose: This study was to identify factors that influence the health care needs of that over 65 years of age in Mokpo, Korea. Method: The data was collected from June 2002 to September 2002. The subjects were 120 homebound solitude elderly(age=76.8). Subjects were interviewed with structured questionnaire in order to identify the health care needs, health variables (perceived health status, risk of malnutrition, K-IADL), psychological variables(self-esteem, depression) and demographic variables. physiological health variables (height, weight, blood pressure, pulse, blood sugar)were assessed after the interview. Result: In general perceived health status was poor, risk of malnutrition was high, number of disease was 3 disease, self-esteem was low but depression was high and health care needs were relatively high. Among the elderly education & counseling needs topped the list. In regression analysis, health care needs were significantly influenced by IADL(23%), duration of solitudes(4%), sex(3%), and education(l%). These variables explained 31% of the variances in health care needs. Conclusion: The result identified that health care needs should be a considered in IADL, female, duration of solitudes and education for the solitude elderly.

The Effects of Mothers' Parental Attitudes on Children's Clothing Benefits with Moderating Effects of Clothing Involvements (어머니의 양육태도가 자녀의복 추구혜택에 미치는 영향과 의복관여의 조절효과)

  • Youn, Cho-Rong;Chung, Kyung-Hwa;Lee, Yu-Ri
    • Journal of the Korean Home Economics Association
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    • v.47 no.3
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    • pp.11-22
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    • 2009
  • The purpose of this study was to identify the benefits in children’'s wear sought by mothers and to identify the influence of parental attitudes and clothing involvements. A survey was conducted and 350 responses collected from mothers who have elementary school-aged children were analyzed using SPSS 15.0 evaluation version. As a result, firstly, eight dimensions of benefits in children’'s wear were identified; individuality/expression, conformity, aesthetics/fashion, social status, functional value, standard, blame avoidance and economic value. Secondly, the influences of mothers’' parental attitudes on the clothing benefits and the moderating effects of clothing involvements were found. The effects of parental attitudes on the benefits were dependent on mothers’' clothing involvements.

A Study on Formation of Void Space by Geometric Method and Environment-friendly Characteristics in Contemporary Housing (현대주거의 기하조작에 의한 보이드 공간의 생성과 친환경적 특성에 관한 연구)

  • Lee, Dong-Ki
    • Journal of the Korean housing association
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    • v.21 no.6
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    • pp.131-141
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    • 2010
  • This study is aimed to grasp the spatial characteristics exhibited in the modern housing architecture from the aspect of a geometrical manipulation, which transforms basic geometrical shapes and persue the formative diversity, to identify and verify the various characteristics of spatial structure in modern housing architecture. In this regard, this paper analyze and identify the influences of the void spaces that are created by geometrical manipulations on housing architecture, in terms of morphological and environmental aspects. Theoretical approaches define the concept of geometrical manipulation according to the characteristics of residence and examine the spatial features of void spaces. Additionally, case studies result in the classification of void spaces that are created by geometrical manipulation. Furthermore, to understand environment-friendly characteristics of the void space, the researcher elicited the factors that can affect environment friendly housing from previous studies, and analyzed their correlation between those factors and the void spaces that are classified.

A Fuzzy Model Based on the PNN Structure

  • Sang, Rok-Soo;Oh, Sung-Kwun;Ahn, Tae-Chon;Hur, Kul
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.06a
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    • pp.83-86
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    • 1998
  • In this paper, a fuzzy model based on the Polynomial Neural Network(PNN) structure is proposed to estimate the emission pattern for air pollutant in power plants. the new algorithm uses PNN algorithm based on Group Mehtod of Data Handling (GMDH) algorithm and fuzzy reasoning in order to identify the premise structure and parameter of fuzzy implications rules, and the least square method in order to identify the optimal consequence parameters. Both time series data for the gas furnace and data for the NOx emission process of gas turbine power plants are used for the purpose of evaluating the performance of the fuzzy model. The simulation results show that the proposed technique can produce the optimal fuzzy model with higher accuracy and feasibility than other works achieved previously.

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