• Title/Summary/Keyword: Lee Don-Hwa

Search Result 114, Processing Time 0.024 seconds

A Study on Congestion Cost Reducing Effect for FACTS Investment using P-POOL (P-POOL을 이용한 FACTS 투입의 경계성 평가 연구)

  • Choi, Don-Keun;Park, Sang-Hyun;Kang, Sang-Gyun;Song, Hwa-Chang;Chang, Byung-Hoon;Lee, Byong-Joon;Kwon, Sae-Hyuk
    • Proceedings of the KIEE Conference
    • /
    • 2006.11a
    • /
    • pp.258-260
    • /
    • 2006
  • 비수도권과 수도권의 수급 불균형 해소를 위한 6개의 북상선로에 흐르는 융통조류량의 한계값이 경제성 평가의 한 기준이 될 수 있다. 본 논문에서는 수도권 융통전력 한계를 고려한 제약급전사례의 검토 결과를 이용하여 FACTS 투입에 따른 증대된 융통전력한계를 바탕으로 FACTS 투입에 따른 혼잡비용측면에서 운전이익을 평가하는 방법을 논한다. 즉, F-V 해석결과를 이용하여, 수도권 융통전력 한계값을 결정하고 좀 더 정확한 운전이익 계산하기 위하여 결정된 한계값을 P-POOL 프로그램을 이용하여 혼잡비용 경감 효과를 확인할 수 있는 모의 방법을 확립한다. 확립된 방안은 계획계통을 이용해 검증하고, 최종적으로 FACTS 투입량과 투입후보지에 대한 융통전력 한계 측면에서의 경제성 평가한다.

  • PDF

원자로 압력용기강의 인성평가를 위한 샤피충격 하중-변위 곡선의 해석

  • Kim, Ju-Hak;Kim, Hun;Ji, Se-Hwan;Lee, Don-Bae;Hong, Jun-Hwa
    • Proceedings of the Korean Nuclear Society Conference
    • /
    • 1996.05c
    • /
    • pp.284-289
    • /
    • 1996
  • 국산 원자로 압력용기강(ASME SA508 cl.3)을 대상으로 표준 샤피충격시험편(2 mm V- notch)과 피로균열(precracked Charpy) 시험편을 제작하여 계장화(instrumented)충격시험을 실시하고, 충격시험시 하중점(load point)의 변위(displacement) 혹은 시간의 변화를 하중의 변화와 함께 측정하였다. 측정결과를 파괴현상 및 파괴역학과 연계시켜 해석하므로서, 가능한한 소량의 시험편(혹은 시험공정)을 사용하여 필요로 하는 인성평가 관련 정보를 획득할 수 있도록 시도하였다. 그 결과, 파괴과정을 나타내는 하중의 변화를 이용하여 Shear fraction 을 예측할 수 있었고, 하중의 변화와 관계된 변위로부터 Lateral expansion을 추정할 수 있었다. 피로균열 시험편 시험결과로 부터는 충격시의 항복하중, 항복변위, 최고하중 등을 획득하여 균열크기의 함수로 표시되는 시험편 Compliance 를 계산하였고, Equivalent energy 법과 J-integral 법을 적용하여 원자로 압력용기강의 탄소성 동적파괴인 성을 평가할 수 있었다.

  • PDF

Polyurethane을 이용한 Thiobacillus sp. IW의 고정화

  • Hwang, Eun-Sang;Im, Geun-Gil;Lee, Gwang-U;Gang, Chun-Hyeong;Ryu, Hwa-Won;Park, Don-Hui
    • 한국생물공학회:학술대회논문집
    • /
    • 2000.11a
    • /
    • pp.536-539
    • /
    • 2000
  • A simple and effective method has been developed for the immobilization of the cell on polyurethane foam. Two types of commercially available polyurethane foam and Hydro-filt were tested. The ultimate purpose of the process is to produce low-cost materials for hydrogen sulfide removal which are being increasingly used for industrial application. Effect of several parameters were studied on the cell loading. These parameters were type, size, and amount of polyurethane foam. MC-70 was the best immobilization material of three type of carriers, and optical particle size was $5{\sim}8mm$ and amount of polyurethane foam was 8g/L.

  • PDF

An Empirical Study on the Efficient Hospital Service Operation Management for the Reduction of Medical Errors (의료과오를 줄이기 위한 효율적인 병원서비스운영에 대한 실증적 연구)

  • Lee, Don-Hee;Choi, Kang-Hwa
    • Journal of Korean Society for Quality Management
    • /
    • v.38 no.4
    • /
    • pp.491-503
    • /
    • 2010
  • This paper presents a research model, which identifies a relationship between medical error reduction, efficiency of organizational systems, and employee satisfaction with organizational support. The proposed model was tested through hypotheses, based on data collected from 210 respondents from the medical staff of large -sized (i.e., more than 500 beds) residential hospitals in cities of South Korea. The results of the study showed that medical error reduction is associated with corrective system and employee satisfaction with organizational support. Therefore, it is very important that organizations improve their employees' satisfaction by providing sufficient support (e.g., information support and sharing, work guide book, etc.) for their work. In addition, in organizational systems, the corrective system has positive relationship with medical error reduction. In terms of corrective procedures, leaders or managers can make improvements by providing and supporting a friendly work environment where errors may be reported without blame and discussed in order to be corrected.

Development of High-Performance Organic Field-Effect Transistors via Surface-Mediated Molecular Ordering

  • Cho, Kil-Won;Kim, Do-Hwan;Park, Yeong-Don;Jang, Yun-Seok;Hwang, Min-Kyu;Lee, Hwa-Sung;Lim, Jung-Ah
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2005.07a
    • /
    • pp.147-148
    • /
    • 2005
  • We report on high-performance organic field-effect transistors by promoting surface-mediated two-dimensional molecular ordering in organic semiconductor. To achieve this goal, we have controlled the intermolecular interaction at the interface between organic semiconductor and the insulator substrate.

  • PDF

Mold Level Stabilization of Continuous Steel Casting Systems Using a Variable Disturbance Observer (가변외란관측기를 이용한 연주시스템의 몰드 레벨 안정화)

  • Sohn, Myung-Gong;Son, Cheon-Don;Kim, Goo-Hwa;Lee, Duk-Man;Kwon, Sung-Ha;Jeung, Eun-Tae
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.14 no.2
    • /
    • pp.105-110
    • /
    • 2008
  • This paper presents a control method to maintain stable mold level for unsteady bulging in high speed casting. The stabilizing mold level is an important factor to get high quality products. But, for various reasons, there are several disturbance factors which make mold level unstable. Bulging is one of disturbance factors and considered for the current stage of study. We design a disturbance observer to attenuate the effect of bulging which is periodic mold level disturbance. Since the period of bulging varies with the casting speed, the parameters of disturbance observer are changed by the casting speed. Simulation is illustrated to demonstrate stable performance of the proposed method in comparison with a previous method in a variable operating frequency.

A Method for Vibration Detection of Squirrel Cage Induction Motors Using the Flux Sensor (자속 센서를 이용한 농형 유도전동기의 진동검출 기법)

  • Hwang, Don-Ha;Lee, Sang-Hwa;Han, Sang-Bo;Sun, Jong-Ho;Kang, Dong-Sik
    • Proceedings of the KIEE Conference
    • /
    • 2007.07a
    • /
    • pp.1057-1058
    • /
    • 2007
  • This paper proposes an alternative vibration detection method in a squirrel-cage induction motor using flux sensors. The air-gap flux will be changed when mechanical vibration occurs by bearing fault as well as broken rotor bar and air-gap eccentricity. For detecting those flux variations due to vibration, search coils are installed at stator slots. The induction motor with 380 [V], 7.5 [kW], 4 [Poles], 1,760 [rpm] ratings is used. Magnitudes and distortion of the induced voltage from flux sensors are used to discriminate faulted types. As a result, the flux sensor has been proven to be useful for vibration detection. It is compared to the result with vibration sensor as well.

  • PDF

A Study on Analysis of Reserves and Available Capacity of Unutilized Energy in Rural Community (농어촌지역 미활용에너지의 부존량과 이용 가능량 분석)

  • Park, Mi-Lan;Ryoo, Yeon-Su;Kim, Jin-Wook;Lee, Yong-Uk;Bae, Sung-Don;Chae, Kap-Byung
    • Journal of the Korean Solar Energy Society
    • /
    • v.34 no.6
    • /
    • pp.19-25
    • /
    • 2014
  • Alternative sources of energy take a higher interest in order to reduce the greenhouse gas under the Climate Change Convention, fossil fuel consumption, and lower social anxiety about nuclear power such as crisis involving the Fukushima plant, problem of obsolete equipment. The energy consumption of agriculture, forestry and fisheries in South Korea is 3,082,000toe by 2011, reliance on electrical energy(35%) and oil(57.2%) is very high with 92.2%. In this study, we examined reserves and available capacity of temperature difference energy for thermal discharge from plant, treated sewage, river water, dam, and agricultural reservoir in rural community. Reserves of unutilized energy are 455,735Tcal/yr in rural community, these accounts for 78% of total reserves 582,385Tcal/y. Thermal discharge from plant has the most reserves of unutilized energy in rural community, it is estimated that it has the reserves of 277,410Tcal/y. Available capacity of unutilized energy in rural community is total 134,147Tcal/y, thermal discharge from plant available for heating is the most 128,035Tcal/y, and it shows in the order of treated sewage 4,318Tcal/y, river water 1,653Tcal/y, and reservoir 141Tcal/y. Elevating temperature area of green house by 2012 is 21,208ha. The amount of energy required for heating the greenhouse a year is dbout 11,365Tcal/y with 8.5% of the total available capacity of unutilized energy.

Blue Mold of Pear Caused by Penicillium aurantiogriseum in Korea

  • Shim, Jae-Ouk;Choi, Kyung-Dal;Hahn, Ki-Don;Lee, Jang-Hoon;Hyun, Ik-Hwa;Lee, Tae-Soo;Ko, Kyoung-Il;Lee, Hai-Poong;Lee, Min-Woong
    • Mycobiology
    • /
    • v.30 no.2
    • /
    • pp.105-106
    • /
    • 2002
  • The isolation of a causal pathogen from pear fruits showing lesions of blue mold was carried out, which were preserved in the packinghouse of Anseong for the export to the United States. When the lesion of pears(Pyrus pyrifolia Niitaka) was checked in packinghouse, their fruit epidermis over decayed parts varied from light tan to dark brown. Also, the decayed flesh was soft and watery, and separated easily from the healthy tissue. Based on the cultural and morphological characteristics, the fungus(IL-12 isolate) was identified as Penicillium aurantiogriseum. This is the first report associated with blue mold of pear caused by P. aurantiogriseum in Korea.

Characteristics of Patients with Allergic Rhinitis through the Pattern Questionnaire Items (변증 설문지 문항을 통해 살펴 본 알레르기 비염 환자의 특성)

  • Son, Jae-Woong;Lee, Kyu-Jin;Jang, Bo-Hyeong;Jang, Soobin;Ko, Seong-Gyu;Choi, In-Hwa
    • Journal of Society of Preventive Korean Medicine
    • /
    • v.18 no.3
    • /
    • pp.81-90
    • /
    • 2014
  • Objective : We performed a clinical study to investigate pattern characteristics in persistent allergic rhinitis depending on Korean Medicine pattern questionnaire items as a pattern identification diagnostic tool. Method : 32 patients with persistent allergic rhinitis were asked to interview with doctor of Korean Medicine and perform the 4 pattern questionnaires(Cold-Heat Pattern, Phlegm Pattern, Yin Deficiency pattern, bloodstasis pattern). Then, we analyzed the response rate of each pattern questionnaires. Results : After diagnosis of Korean Medicine Doctor's pattern identification, 17 individual items have higher response rate, 7 of 17 items have a common tendency in allergic rhinitis. The other 8 of 10 items belong to Lung qi deficiency cold and Lung-spleen qi deficiency group, these have higher tendency of deficiency. In bloodstasis pattern questionnaires, we don't decide the tendency of patients with allergic rhinitis. Conclusion : The result may provide that we don't use Korean Medicine pattern questionnaires as a major tool in the pattern identification of allergic rhinitis. Continuous studies are needed to develop the standardized pattern identification diagnostic tool.