• 상하수도학회지
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• 제20권1호
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• pp.35-43
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• 2006

Concerns related to protecting, identifying, and isolating of subsystems of a water distribution network have led to the realization of the increased importance of valves in the system. The most important purpose of valves in water distribution systems is to isolate a subsystem due to breakage, maintenance activities, or contamination. A subsystem called segment is isolated by the closure of adjacent valves. Minimizing the pipe failure impact, an efficient algorithm is required to identify adjacent valves quickly. In this paper, an algorithm to identify adjacent valves to be closed to isolate a subsystem from the remainder of a network when a pipe failure is presented. The algorithm is operated on a matrix called the valve location matrix containing the information of valve locations. An application to an existing water distribution system demonstrates the developed algorithm efficiently locates the adjacent valves for the isolation of a broken pipe.

• Journal of Advanced Marine Engineering and Technology
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• 제30권3호
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• pp.396-402
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• 2006

In this study, dynamic characteristics of water hammer pressure in water supply piping system with water hammer arrester has been investigated experimentally to characterize the transient pressure of water hammer in high rise building. Experiments were conducted to verify the absorption effects by water hammer arresters with 3 different gas volumes of water hammer pressure generated by sudden valve closure. As the results, it has been found that zoning and sizing of pipe diameter for suitable flow velocity and water hammer arresters with effective pressure absorption capacity have to be installed to protect water hammer problems in building water supply piping system.

• International Journal of Air-Conditioning and Refrigeration
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• 제9권2호
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• pp.51-61
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• 2001

A numerical study has been conducted to characterize the transient pressure in a simple water supply pipe system with an air chamber by utilizing a commercial code that employs the method of characteristics. Some results produced for validation in the study agree quite well with the previously reported. Several parameters are than varied. Among them are the valve closure time, the wave speed, the static pressure, the polytropic exponent, the air chamber volume, the diameter and the shape of orifice in the air chamber, etc, while the water temperature and velocity are kept constant at $20^\circ{C}$ and 0.8m/s, respectively. Results reported in this parametric study may be useful to understand the unsteady behavior of the system.

• 방사성폐기물학회지
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• 제11권2호
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• pp.157-178
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• 2013

사용후핵연료 최종처분을 위해 심층처분은 세계적으로 가장 선호되는 방법이다. 이를 위해 선진국들은 자국 여건에 가장 잘 부합되는 고유의 처분시스템 개발에 주력하고 있거나, 일부 확보하여 상용처분사업에 적용하고 있다. 현재까지 알려진 대부분의 심층처분시스템은 공학적 및 천연방벽으로 구성된 다중방벽시스템이다. 이들 처분시스템은 수 천 년 ~ 수 십만 년 이상의 성능기간이 대하여 성능 안전성의 입증이 확인되어야 후속 상용처분사업에 적용 가능하다. 입증 현안과제들은 처분시스템의 상능 안전성 확보를 위해 수행되는 모든 행위 즉, 조사, 분석, 해석, 평가, 설계, 건설, 운영 및 폐쇄에 이르는 전 과정에 있어서 추진 과정과 결과에 대한 실현 가능성과 실증에 필요한 내용들이 해당된다. 이를 위해 대부분의 선진국들은 자국내 분포하는 대표적인 선호암종 지역에서 지하연구시설(URL)을 건설하여 실증 시연프로그램을 수행하거나 완성단계에 있다. 이 과정과 결과들은 후속되는 최종처분장 부지선정 과정에 평가기준으로 활용될 것이며, 최종처분시설의 성능 안전성평가에 필수적으로 적용하게 된다. 지하연구시설은 또한 규제-일반대중-전문가 등 다양한 이해당사자들로 하여금 심층처분의 안전성 수준에 대한 이해제고와 토론의 마당으로서 핵심적인 역할과 기능을 할 것으로 기대된다.

• Journal of Chest Surgery
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• 제48권2호
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• pp.99-104
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• 2015

Background: We report our initial experiences of robot-assisted cardiac surgery using the da Vinci Surgical System. Methods: Between February 2010 and March 2014, 50 consecutive patients underwent minimally invasive robot-assisted cardiac surgery. Results: Robot-assisted cardiac surgery was employed in two cases of minimally invasive direct coronary artery bypass, 17 cases of mitral valve repair, 10 cases of cardiac myxoma removal, 20 cases of atrial septal defect repair, and one isolated CryoMaze procedure. Average cardiopulmonary bypass time and average aorta cross-clamping time were $194.8{\pm}48.6$ minutes and $126.1{\pm}22.6$ minutes in mitral valve repair operations and $132.0{\pm}32.0$ minutes and $76.1{\pm}23.1$ minutes in myxoma removal operations, respectively. During atrial septal defect closure operations, the average cardiopulmonary bypass time was $128.3{\pm}43.1$ minutes. The median length of stay was between five and seven days. The only complication was that one patient needed reoperation to address bleeding. There were no hospital mortalities. Conclusion: Robot-assisted cardiac surgery is safe and effective for mitral valve repair, atrial septal defect closure, and cardiac myxoma removal surgery. Reducing operative time depends heavily on the experience of the entire robotic surgical team.

• 농촌의학ㆍ지역보건
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• 제25권2호
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• pp.217-230
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• 2000

For the longest time, our government has played an inconsiderable role in the public health services of Korea, especially as it relates to their investment. Voices have cried out against increases in national health expenditure and for more establishment of public medical facilities. In light of this, the necessity and importance of public medical facilities have come into focus amidst the recent medical crisis. When public medical facilities filled in the gap created by the suspension or closure of private hospitals and clinics as a result of this national crisis and acted as a safety net, the demand for more establishment of such facilities increased. Although patient diagnosis and treatment are the first priority of public medical facilities, they must also deal with scopes that private medical facilities do not deal with, dislike, or have difficulty with. In this respect, the closure or privatization of public hospitals to reduce their number just because of their low profits or financial burdens that must be carried by the government is to ignore their innate importance and social role; therefore, we must do all we can to block such efforts and further empower these public health facilities according to demands of the time. The improvement of public health services can be realized by redefining its goals and roles, increasing government funding, strengthening of existing public health facilities and reorganizing the public health services system. Even if public health facilities were to increase their medical services and be reinforced, they cannot take on all the services related to public health services, Therefore, in a country like ours where public health services come second to private health services in the health care system, the health of citizens can be safeguarded only when private and public facilities cooperate and private medical facilities share the social responsibilities. Only the show of interest and effort by government, politicians, health professionals, professional organizations and public can initiate the improvement that is sought.

• 대한의용생체공학회:의공학회지
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• 제20권4호
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• pp.427-433
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• 1999

본 논문에서는 고음질 음성부호화 및 압축, 음성인식 및 합성등의 성능개선에 있어서 중요한 파라메터인 피치정보를 실시간으로 검출하기 위해 연구를 수행하였다. 이를 위하여 변복조 스폿(spot) 전극을 적용한 새로운 EGG(Electroglottograph) 측정 시스템을 개발하여 이용한 안정된 피치검출 알고리즘을 연구하였다. 구체적으로 EGG 신호에 의한 성문 닫힘시점을 실시간으로 결정하여 EGG 기반의 피치궤적 알고리즘을 개발하였고, 음성신호만의 피치궤적 추적기와 성능비교를 수행하여 우월한 성능을 가짐을 보였다. 또한, EGG 신호를 이용한 음성분석을 수행하여 한국인에 있어서 성문의 다양한 진동신호 패턴의 측정 및 분석을 통해 한국인 음원의 모델과 성문신호 패턴에 대한 정량적인 해석을 하였다.

• 한국학교보건학회지
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• 제28권3호
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• pp.188-199
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• 2015

Purpose: This study aims to understand schools' response to infectious disease, perceived problems and suggestions, with regard to the 2015 MERS outbreak in South Korea, in order to improve the infectious disease response system. Methods: Data were collected by focus group interviews with three groups composed of school health teachers, other teachers, and parents in Seoul-located schools. Results: The major theme was "Schools' Discretionary Response in the Absence of the Control Tower." Four major categories and 11 sub-categories were drawn from the findings. Four major categories were as follows: (a) Temperature monitoring caused lots of complaints, (b) Closure decisions were left at the discretion of schools, (c) Precautions are now being more emphasized, and (d) The support system were malfunctioning. Conclusion: The main areas to be improved are as follows: (1) School district offices should have an expanded role in infectious disease response and build cooperative partnerships with health authorities. (2) Preparedness for infectious disease should be strengthened. (3) Temperature monitoring systems should be improved, (4) Closure decisions should be made at a local community level. These are expected to help schools establish advanced infectious disease response systems.

• Structural Engineering and Mechanics
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• 제62권6호
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• pp.719-724
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• 2017

We consider an elastic isotropic plate reinforced by stringers and weakened by a periodic system of rectilinear slots of variable width. The variable width of the slots is comparable with elastic deformations. We study the case when the slots faces get in contact at some area. Determination of parameters characterizing the partial closure of variable width slots is reduced to the solution of a singular integral equation. The action of the stringers is replaced with unknown equivalent concentrated forces at the points of their connection with the plate. The contact stresses and contact zone sizes are found from the solution of the singular integral equation.

• 한국전산유체공학회지
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• 제14권1호
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• pp.35-44
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• 2009

To adequately analyze flows in pipe or duct network system, traditional node-based junction coupling methods require the junction loss which is specified by empirical or analytic correlations. In this paper, a new finite volume junction coupling method using a ghost junction cell is developed by considering the interchange of linear momentum as well as the important wall-effect at junction without requiring any correlation on the junction loss. Also, boundary treatment is modified to preserve the stagnation enthalpy across boundaries, such as pipe-end and the interface between junction and branch. Also, the computational accuracy and efficiency of the Godunov-type finite volume schemes are investigated by tracing the total mechanical energy of rapid transients due to sudden closure of valve at downstream end.