• 제목/요약/키워드: Common

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Reducing Common-Mode Voltage of Three-Phase VSIs using the Predictive Current Control Method based on Reference Voltage

  • Mun, Sung-ki;Kwak, Sangshin
    • Journal of Power Electronics
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    • 제15권3호
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    • pp.712-720
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    • 2015
  • A model predictive current control (MPCC) method that does not employ a cost function is proposed. The MPCC method can decrease common-mode voltages in loads fed by three-phase voltage-source inverters. Only non-zero-voltage vectors are considered as finite control elements to regulate load currents and decrease common-mode voltages. Furthermore, the three-phase future reference voltage vector is calculated on the basis of an inverse dynamics model, and the location of the one-step future voltage vector is determined at every sampling period. Given this location, a non-zero optimal future voltage vector is directly determined without repeatedly calculating the cost values obtained by each voltage vector through a cost function. Without utilizing the zero-voltage vectors, the proposed MPCC method can restrict the common-mode voltage within ± Vdc/6, whereas the common-mode voltages of the conventional MPCC method vary within ± Vdc/2. The performance of the proposed method with the reduced common-mode voltage and no cost function is evaluated in terms of the total harmonic distortions and current errors of the load currents. Simulation and experimental results are presented to verify the effectiveness of the proposed method operated without a cost function, which can reduce the common-mode voltage.

전기철도의 공용접지 시스템에 대한 안정성 평가에 관한 연구 (Safely Evaluation on Common Grounding System for Electric Railway)

  • 송진호;황유모
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제51권6호
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    • pp.298-306
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    • 2002
  • We performed an safety evaluation on constructing of a common grounding system for electrical railway in view of its efficacy and technical fit. In order to compare the conventional grounding method, which has been individually conducted, with the common grounding with all ground wires connected in common to the counterpoise buried below the surface of the earth in parallel with rail, we set up scenarios with several cases of fault and load conditions in Chungbuk railway sections with the common grounding system. Based on models for railway conductors including the grounded system, line Parameters of railway power system are computed. The circuit model for power system with up and down lines, auto-transformers and railway substations is used to compute impedances of counterpoise and substation ground net. For each scenario with faults and operation conditions of railway, the induced potentials on signal and communication lines are also computed. It is shown that the common grounding for Chungbuk railway is superior experimentally to the conventional method in three respects: (1) the lower rail potentials during operation of railway in line, (2) the lower rail potentials for short-circuit faults between catenary and rail, and (3) the lower stress voltages on signal and communication lines for short-circuit or ground faults. The analysis results confirm that the grounding system for electric railway is required to be built by the common grounding and be evaluated on its safety in design.

종합병원의 병동부 기능공간 구성비율에 관한 연구 (A Study on the proportion of functional Areas in the ward of General Hospitals)

  • 권순정;주소현
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제17권4호
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    • pp.49-55
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    • 2011
  • This study proposes proportions of functional areas in the ward of general hospitals, which are derived from 5 big university hospitals in order to establish the ward area standard for hospital design. The results of this paper are as follows. First, functional areas of hospital ward are composed of bedroom area, nursing area, training area, service area, and common area. Of course common area can be divided into first common area and secondary common area. The first common area(inter departmental common area) includes lobbies, elevator lobbies, corridors, restroom, and mechanical shafts. The secondary common area means the common area within special department such as ward or radiology department. Second, a standard method of calculating ward areas has been proposed: the standard is based on the center line of the wall between functional areas. Third, the proportions of 6 functional areas in ward are suggested.

마을길에 따른 공유공간과 경관형성에 관한 연구 (A Study on Common Spaces and Building Landscape with Sharing according to Village Lane Pattern)

  • 정건채
    • 한국농촌건축학회논문집
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    • 제20권1호
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    • pp.37-44
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    • 2018
  • The purpose of this study is to know how to make common space, find a type of it, and build a village landscape with it in countryside. There are five types of village including suburban according to typological locality in rural area. Each of them have remarkable common spaces that are combined with community identity and usage. They usually are located along with the street and lane of the village. Most of the villages I surveyed have common places for residents to rest, share, and meet together. Representatively, pavilion with symbolic tree we call Jeonja is very popular place to them, and village people also require public parking or pocket park in their modern life. I researched common places in ten communities in rural area so that I can suggest a way of community design through them. According to this research, there are three results. First, the common space of the village is placed to motivate emotional and attractive community design in the village. Second, the common space has an identity and landscape architectural relationship to build sustainable community. Third, countries' streets that I surveyed have four types, which are liner, tree, loop, and radiate patterns of lane. In line with those types, each one makes different and historical community landscape.

여성의 월경통 경험에 대한 현상학적 연구 (A Phenomenological Study on Dysmenorrhea Experience of Women)

  • 함미영;한경순;유수옥;박경숙
    • 여성건강간호학회지
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    • 제5권2호
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    • pp.288-299
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    • 1999
  • The purpose of this research was to understand the dysmenorrhea experience of women. To do this work, we asked 9 women a lot of questions about dysmenorrhea. The interviews were carried out from JUL 1, 1998 through JUL 30, 1998. They were audio-recorded and analyzed using Van kaam's Phenomenological method. Results were as follows. One hundreds forty two descriptive expression were found and they were grouped under twenty common factors. twenty common factors were grouped under six higher categories. Two common factors, "Physical pain", "Physical Discomfort" were grouped under . Three common factors, "Receptively of Femininity", "Women's Persecution", "Mystery of Femininity" were grouped under . Three common factors, "Emotional Anxiety", "Disgust of Pain", "Solitude" were grouped under . Two common factors, "Coping with Pain Relief", "Fear of Pain relief method" were grouped under . One common factors "Beauty" were grouped under , One common factors, "Singularity" were grouped under . As Dysmenorrhea Experience of Women's authors recommend further studies on Women's Dysmenorrhea Experience and go into details nursing intervention of Dysmenorrhea relief method.

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요추 추간판 탈출증 환자 30예(例)의 요추신연법 병용(倂用)에 대한 임상적(臨床的) 고찰(考察) (The clinical effects of chuna treatment for HNP)

  • 김재홍;조명래;채우석
    • Journal of Acupuncture Research
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    • 제20권3호
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    • pp.229-237
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    • 2003
  • Objective : The purpose of this report is to usee more Chuna treatment clinically by comparing the improvement of Back pain and Sciatica between Common treatment Group and Common treatment with Chuna treatment Group. Methods : This study was carried out on 30 patients with Back pain and Sciatica who ere hospitalized in Dongshin Univ. Oriental Hospital form April 2001 to December, 2002. Group A of 15 patients wer taken both common treatment and Chuna treatment. And Group B of 15 patients were only taken common treatment. And after 10 days of admission, we checked and compared VAS(Visual Analogue Scale) and improvement index out of these two groups. Results : The result of the VAS(Visual Analogue Scale) and improvement index of comparison analysis between two groups after 10 days, shows that the improvement of Back pain and Sciatica in Common treatment with Chuna treatment Group is more effective than that in Common treatment Group.

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미토콘드리아 12S rRNA 유전자 변이 조사를 통한 잉어(Cyprinus carpio)의 유전학적 동정 (Genetic Stock Identification of Common Carp (Cyprinus carpio) by Detection of Intraspecific DNA Sequence Variation in the Mitochondrial 12S rRNA Gene)

  • 남윤권;주수동;정창화;노충환;조재윤;김동수
    • 한국양식학회지
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    • 제10권4호
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    • pp.403-407
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    • 1997
  • Intraspecific sequence variation was detected by polymerase chain reaction (PCR) and direct sequencing of a 350-nucleotide region of the mitochondrial 12S rRNA gene of two natural populations (Han River and Nakdong River) and one hatchery stock (Jinhae Inland Fisheries Institute) of local strain common carp, one Israeli strain of common carp stock from Pukyong National University (PKU), and one hybrid between Israeli strain of common carp female and local strain common carp male from PKU stock. There is little variation in 350 bases of the mitochondrial 12S rRNA gene sequences among 2 natural and 1 hatchery local strain common carp populatins, representing abut 7 to 20 nucleotide differences (less than 6%). The sequence of specimens from Han River was more similar to that from Nakdong River (identity=98.0%) than to that from Jinhae Inland Fisheries Institute (identity=96.3%). Sequence variation between Israeli strain and wild local strain common carp was higher than the variation within natural stocks. The level of variation was ranged from 15.7 to 17.7%. The hybrid showed very similar nucleotide4 sequence of 12S rRNA gene to the sequence of Israeli strain with the identity of 98.9%.

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간호 대학생의 기본 간호 실습 경험에 대한 연구 (A Study on the Experience of Fundamental Nursing Practice)

  • 한경순;조주연
    • 대한간호학회지
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    • 제29권2호
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    • pp.293-303
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    • 1999
  • The purpose of this study was to understand and to explain how were nursing students experienced and accepted the fundemental nursing practice. In addition to, the results of this study are attempted to contribute for offer of basic data in projecting and accomplishing to promote quality practice education. The participants were 79 freshmen of S College of Nursing in kyungi-do. They presented record of feeling and thinking on their the fundemental nursing practice experience. The data were collected from 29, J une to 10, July in 1998. Collected data was analyzed by means of Van Kaam's phenomenological method. The results of this study was founded 423 descriptive expression and they were grouped under 42 common factors and they were grouped under 9 categories. By means of the frequency on the categories. the higher category is Anxiety. next Solemn. Flutter. Pride. Usefulness, Recognition of reality in nursing-system. Lack of practice environment. Self-accusation. Comprehension of nursing spirit were founded. 5 common factors. Tension. Difficulty, Dread. Apprehension, Burden were grouped under Anxiety. 7 common factors, Pledge, Memory, Importance of practice, Sincerity, Restriction of dress, Acceptance, Active attitude were grouped under solemn. 5 common factors, Interest, Strange, Beanimated, Waiting, Curiosity were grouped under Flutter. 5 common factors, Conceit, Self-confidence, Skilled, Worth, Accomplishment were grouped under Pride. 6 common factors, Acknowledge of nursing affairs, Expectation of furture, Fascination of nursing. Acquirement of disposition of nurse, Association of injection, Actual feeling of dept. of nursing were grouped under Recognition of reality in nursing-system. 4 common factors, Lack of practice time, Many persons of practice, Lack of practice instrument, Lack of reality were grouped under Lack of practice envirnment. 5 common factors, Inconvenient, Reflection, Loss of pride, Shyness, Feeling sorry were grouped under Self-accusation. 3 common factors, Utility, Connection of practice and theory, Various experience were grouped under Usefulness. 2 common factors, Comprehension on the dignity of human, Comprehension on a point of view of patient were grouped under Comprehension of nursing spirit. In conclusion, the following recommendation should be necessary a supplementary study to approach on the type of students that has a firm view and care about client prior to clinical nursing practice.

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정렬형 관 배열에서의 와류발생기 응용 (Application with Winglet-Type Vortex Generators in an In-line Tube Arrangement)

  • 곽경민
    • 에너지공학
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    • 제14권4호
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    • pp.241-247
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    • 2005
  • 3열 정렬형 관군 배열에서 3열의 'common flow up'과 'common flow down' 형상의 와류발생기를 부착하여 와류발생기에 의한 열전달 촉진과 압력강하를 비교하였다 선행 연구자들이 제안한 'common flow down' 형상의 와류발생기는 와류발생기가 없는 휜-관군에 비해 열전달 촉진은 $10\%{\~}25\%$ 향상되었고, 압력강하는 $20\%{\~}35\%$ 증가하였다. 'common flow up' 형상의 와류발생기의 경우 후연 수평거리(${\Delta}y$)를 변화시키면서 평가하였다. 와류발생기는 삼각형과 사각형 형상을 적용하였다. 후연 수평거리(${\Delta}y$)가 5mm이고 삼각형의 'common flow up' 형상의 와류발생기가 정렬형 관군에서 설치될 때 Reynolds수(유로 높이의 배를 기준으로)가 $300{\~}2700$ 범위에서 열전달촉진은 10까지 향상하였고, 동시에 압력강하는 $8\%{\~}15\%$ 감소하였다. 삼각형 와류발생기가 부착된 휜-관군의 성능이 상대적으로 작은 압력강하 때문에 사각형 와류발생기가 부착된 휜-관군의 성능보다 좋게 나타났다.

공동주택 공유공간 연구의 흐름에 관한 연구 - 국내 학술지 게재 논문을 중심으로 - (Trend of Common Space in Multi-unit Dwelling Through Domestic Research - Focused on the Research Published in Domestic Journals -)

  • 이학성;안소미;이연숙
    • 한국실내디자인학회논문집
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    • 제27권3호
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    • pp.126-135
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    • 2018
  • In the 1960s, rapid urbanization and industrialization created the social atmosphere of individualism in Korea. Individualism has weakened social ties, led to the breakdown of communities, and caused various social problems. So, the paradigm is shifting to a shared society and there are moves to seek ways to solve social problems through community. As part of the initiative, the value and importance of common space in multi-unit dwelling, the typical Korean housing type, is increasing. Thus, the purpose of this study is to identify the trends of domestic research about common space, to assess the current state of domestic academic world and explore the future plans of the common space. The content analysis method was mainly used and statistics were additionally used to analyze 172 preceding research. As a result, research on common spaces showed a steady increase to the current time. And research was being diversified in the field of publishing journals, research contents, research methods and facilities. Until now, most studies have focused on improvement of plan and the quality of common space by identifying the attitude survey, space planning, and the actual situation. Thus many more studies about proper way to operate and manage common space need to be conducted. it is considered that the common space will develop more efficiently. The study is expected to be used as groundwork for the development of the common space and serve as concrete data to show future development directions.