• 제목/요약/키워드: circle analysis

검색결과 523건 처리시간 0.027초

선회스크롤의 편심질량을 고려한 스크롤압축기의 성능해석 (Performance analysis of scroll compressor considering eccentric mass of orbiting scroll)

  • 박승철;이진갑
    • 설비공학논문집
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    • 제11권5호
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    • pp.605-614
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    • 1999
  • Orbiting scroll mass center is different from the basic circle's for the normal involute profile. As for the orbiting scroll balanced conditions, the dynamic modeling are set up. The influences on sealing, reaction forces between the moving elements and forces from the moving elements to the compressor frame are analyzed in this paper. The simulation and experiment results are presented.

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불연속 동작특성을 갖는 전력계통의 RCF법을 사용한 고유치 해석 : 상태천이 방정식으로의 모델링 (Eigenvalue Analysis of Power Systems with Non-Continuous Operating Elements by the RCF Method : Modeling of the State Transition Equations)

  • 김덕영
    • 대한전기학회논문지:전력기술부문A
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    • 제54권2호
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    • pp.67-72
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    • 2005
  • In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this paper, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition equations. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

불연속 동작특성을 갖는 전력계통의 RCF법을 사용한 미소신호 안정도 해석 : 상태천이 방정식으로의 모델링 (Small signal stability analysis of power systems with non-continuous operating elements by using RCF method : Modeling of the state transition equation)

  • 김덕영
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 A
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    • pp.342-344
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    • 2004
  • In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this research, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements'. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition matrix. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

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화상분석기를 이용한 정도별 이형성증에 대한 연구 (The Study of Dysplasic Grades to Digital Image Analyzer)

  • 주경웅
    • 대한임상검사과학회지
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    • 제38권3호
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    • pp.203-207
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    • 2006
  • The purpose of this study was to develop discriminant analysis models for predicting cervical normal/dysplasia case diagnoses using cytometric features derived from the digital image analysis of cell monolayers. The database consisted of 19 cases diagnosed either as normal (n=5), moderate dysplasia (n=7), severe dysplasia (n=7) on monolayer preparations. We studied the nuclear and cytoplasmic characteristics of cells in the normal, moderate dysplasia and severe dysplasia on cervical samples. The morphometric parameters selected for the analysis were nuclear/cytoplasmic ratio and the nuclear variations measured by image analysis on normal and precancerous lesions of cervical smears; several shape factors; area; perimeter; maximal, minimal and equivalent circle diameters. The results showed that the dysplasia samples exhibited changes in both cellular and nuclear form and size but lacked substantial differences in the tumor grades. The coefficient of nuclear variation is as follows to normal cell $21.8{\pm}3.2%$, moderate dysplasia $33.5{\pm}6.1%$, severe dysplasia $27.7{\pm}5.8$ of cervical smears.

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수치해석을 이용한 와전류센서의 특성해석 (Characteristics Analysis Eddy Current Sensor Using by Numerical Analysis)

  • 최덕수;이향범;나은진
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 B
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    • pp.1000-1002
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    • 2003
  • The characteristics of eddy current sensor has been analyzed by using numerical analysis which is performed by modeling eddy current sensor and analytic object into three-dimension axis-symmetry in this paper. The eddy current sensor is modeled as cylindrical shape with variation of inside and outside diameter and frequency range between 1[kHz] and 1[MHa] for numerical analysis. The value of impendence on eddy current sensor depending on frequency variation was calculated through numerical analysis. The characteristics of eddy current sensor can be studied by normalized impendence which is gained from the calculated impendence. Therefore, sensitivity of eddy current sensor depending on frequency, inside and outside diameter can be known by investigating diameter of half circle impendence and its locus.

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산업용 CR영상의 방사선 강도에 따른 잡음특성과 기하학적 구도형성의 해석적 접근 (Analytical Approach for the Noise Properties and Geometric Scheme of Industrial CR Images according to Radiation Intensity)

  • 황중원;황재호;박상기
    • 대한전자공학회논문지SP
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    • 제46권1호
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    • pp.56-62
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    • 2009
  • 산업용 강판튜브 CR영상의 잡음특성과 기하학적 구조에 관한 해석적 접근을 시도한다. 산업현장에서 방사선 측정실험으로 직접 취득한 방사선영상을 방사선강도에 따라 30(개) 이상의 샘플을 수집하였다. 이들 각 영상은 배경부, 두께부 및 튜브내부의 세 영역으로 구성되었는바, 그 가운데 튜브내부영역을 분석 대상으로 삼았다. 통계적이고 함수적인 방법론에 의해 잡음특성을 포함한 기하학적 구조를 분석한다. 영상을 구성하는 화소라인별로 또는 공간적으로 분석을 수행하여 강판튜브의 기하학적 원형 형태가 방사선영상화 과정을 거치면서 일어나는 변형과 잡음속성 변화의 두 가지 특성을 규명한다. 분석시 부합함수와 그 오차를 기하학적 변형의 판별인자로, 표준편차, 평균 및 SN비를 잡음특성 판별인자로 설정하고 방사선투과정도의 영상에서의 실현인 회색도 변화에 따른 이들 인자들의 변화를 고찰하였다. 분석결과, 본래의 원형 구조가 방사선투과 강도에 따라 타원형에서 저반경 원형 그리고 고반경원형의 점차적인 구조 변형을 일으킨다는 사실을 밝혔고, 잡음의 편차가 투과강도에 반비례함을 규명하였다.

여성건강을 위한 개념적 모형 (Conceptual Model for Women s Health)

  • 이경혜
    • 대한간호학회지
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    • 제27권4호
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    • pp.933-942
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    • 1997
  • There has recently been an increased interest in women's health from, various disciplines, with different perspectives presented according to each profession's academic background. This has led to many instances of incorrectly defining, or misinterpretation, of the issues even among professionals. Nurse scholars as well as practitioners who work in women's health care need to have a clear conceptual understanding of women's health in order to build a body of knowledge, delineate curricular activities, and set directions for professional nursing interventions. In addition, a conceptual model that may be directly utilized in practice is needed to maintain and promote women's health issues. The purpose of this study was to apply a Hybrid model, analyzing conceptual definitions and discussions related to women's health gathered from review of the literature. Further to compare analyticals the concepts and properties observed from field work, so as to present a final definition of women's health and, build a conceptual framework for a united comprehensive perspective on the concept as well as on nursing practice. Data collection and analysis consisted of a theoretical stage, field work stage, and final analysis. A heterogeneous group of professionals and lay persons, 39 in all, participated in the field work. Study findings Include several subconcepts under the concept of women's health : a woman's whole life, holistic health, quality of life, awareness of being a woman, individual nursing, self care ability, reproductive health, and family health. Thus, a comprehensive definition was built, 1. e., "Women's health care be defined as improvement in the quality of life of women through attainment of holistic health throughout the life span. With reproductive health at the core, the concept is directly related to family and national health, and includes taking care of one's own health based on awareness of being a woman and utilizing self care activities. Women's health care issues are unique and allow various responses, therefore women's health professionals need to apply individual approaches to reach solutions in attaining holistic health and improving quality of life." The constructual factors of women's health were found to be reproductive functions, diseases more common in woman, self actualization, mental health, women's health policies, sexuality, midlife changes, and marital relations, with each factor having more than three properties. Positive factors affecting women's health were found to be a normal childbearing process, a healthy lifestyle, active health management, health information, support, and resources, and interpersonal relationships. Negative factors were found to be overwhelming role stress, cultural oppression, gender inequality, distorted sexual identity, economic difficulties, misuse and/or abuse of substances, and stress. The model of women's health may be visualized as a balance scale set upon a woman's life, supporting 4 concentric circles. The innermost circle and second circle incorporate conceptual definitions of women's health, and the outer two circles represent the constructional factors and properties of women's health. Each circle has its own color that symbolizes the conceptual meaning. Positive and negative factors are represented as weights at either end of the scale, and are affected by nursing intervention, i. e., health and wellness increase when positive factors are stronger, whereas disease and illness increase when negative factors are stronger. This model is only a preliminary effort and requires much discussion and testing to be further developed. Continuous research is also required.

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청초(淸初) 학술계의 춘추학(春秋學)에 대한 이해와 평가 - 『사고제요(四庫提要)』 「경부(經部)·춘추류(春秋類)」를 중심으로 (Understanding and Evaluation of Spring Autumn-Hak by Academic Circle of the Early Qing Dynasty - Focused on 「Gyeongbu·Spring Autumn」,『Sagojeyo』)

  • 김동민
    • 한국철학논집
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    • 제32호
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    • pp.337-370
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    • 2011
  • 청초의 학술계는 "사고제요"의 편찬이라는 사건을 계기로 한학(漢學) 중심의 학술사조가 새롭게 형성되었으며, 춘추학 분야에서도 새로운 변화가 모색되었다. 본 논문에서는 "사고제요"의 춘추관(春秋觀), 그 중에서도 특히 전통적인 춘추학(春秋學)의 전개 과정과 양상에 대한 "사고제요"의 이해와 평가를 살펴보았다. "사고제요"에서는 공양학(公羊學)과 곡량학(穀梁學), 그리고 송학(宋學) 계열 학자들의 "춘추"해석에 대한 비판적 분석을 시도했는데, 그것은 춘추학의 새로운 연구방법론을 구축하기 위한 사전 사업의 성격을 띤다. "사고제요"에서는 "좌씨전"의 중요성을 주장하면서도 그 단점을 과감하게 지적하고, 그것의 보완을 위해 "공양전"과 "곡량전"의 장점을 적극적으로 수용할 것을 요구한다. 심지어 주요 비판의 대상인 송대 춘추학 분야에 대해서도 학파적 편견을 최대한 배제한 채, 객관적이고 합리적으로 평가하려고 노력하였다. "사고제요"에서 이와 같은 세밀하고 객관적인 분석이 선행되었기 때문에 춘추학 분야는 "사고제요"의 편찬을 기점으로 새로운 전환점을 맞이할 수 있었다. 역사적 사실에 대한 고증과 의리 담론을 종합적으로 판단하는 새로운 연구방법론은 청초 한학 중심의 학술계에서 발굴한 주요 성과의 하나라고 할 수 있다.

북극권 자원 개발 사업을 위한 기후변화 대응 방안 조사 분석 (Investigation and Analysis of Climate Change Countermeasures for Resource Development Projects in the Arctic Circle)

  • 김세원;김영석
    • 한국지반신소재학회논문집
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    • 제20권4호
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    • pp.73-84
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    • 2021
  • 최근 지구온난화에 따른 이상 기후 현상으로 세계적으로 환경 문제에 관한 관심이 높아지고 있다. 기후변화에 적극적으로 대응하기 위해 전 지구적인 노력이 이어지고 있으나, 여전히 화석연료의 의존도는 매우 높다. 특히, 북극권은 막대한 양의 화석연료와 광물자원이 매장되어 있어 개발과 건설 사업이 활발히 추진되고 있다. 북극권 자원(석유·가스자원) 개발 사업의 참여 및 협력은 우리나라 에너지·자원 공급의 대안 중 하나라 할 수 있다. 북극권 자원 개발은 극한 기후에 따른 열악한 개발 환경과 기술적 한계, 자원 개발에 따른 환경 문제, 사회적 영향 등 일반적인 자원 개발과 비교해 사전에 면밀한 검토가 요구되고 있다. 본 논문에서는 북극권 자원 개발 및 건설 활동 추진을 위해 북극해 연안 국가들의 기후변화 대응 법규 및 지침을 고찰하였다. 또한, 북극권 자원 개발 사업을 위해 필요한 영구 동토층의 지반 안정화 기술, 극한의 기후 조건에 작동하고 자원 개발의 효율성을 높일 수 있는 기술 사례 등을 조사하고 분석하였다. 본 연구의 조사·분석 결과는 자원 개발 사업의 성공적 추진과 운영을 좌우하는 새로운 리스크 요인에 대응하는 전략수립 등에 활용될 것으로 기대한다.

Thyristor 직류 Chopper방식으로 구동되는 직류타여자식 전동기의 과도특성해석법 (Transient Characteristics of Separately Excited d-c Motor Driven by Thyristor d-c Chopper)

  • 천희영
    • 전기의세계
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    • 제21권2호
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    • pp.9-19
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    • 1972
  • The transient characteristics of separately excited d-c motor driven by thyristor d-c chopper is studied in this paper. The armature controlled system is applied. As a result of theoretrical analysis the following conculsions were drawn: (1) For the transient analysis, it is recognized that the state transition analysis is a more general method and powerful tool than the state equation method or signal flow graph method, although it includes iterative matrix calculations. And the system is dealt with a finite width sampled-data system in the state transition analysis. (2) The transient characteristics of the motor angular velocity and its torque to the sampling duration variation are compared with those due to the amplitude variation of d-c chopper voltage as follows. The attenuation rate of the transient characteristics is equal in both cases, but the initial value of the transient characteristics in former case is greater than in latter case. (3) The roots of characteristics equation of the system lie inside the unit circle of the Z-plane. Therefor the system is stable. Further it is found that as the sampling duration is decreased the relative stability is lessened.

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