• Journal of Chest Surgery
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• v.38 no.11 s.256
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• pp.761-772
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• 2005

Background: Following the implantation of heart valve prostheses, it is important to maintain therapeutic INR to reduce the risk of thromboembolism. The objective of this study was to suggest a practical dosing guideline for Korean outpatients with prosthetic heart valves managed by a pharmacist-run anticoagulation service (ACS). Material and Method: A retrospective chart review was completed for all patients enrolled in the ACS at Seoul National University Hospital from March, 1997 to September, 2000. Patients who were at least 6 months post-valve replacement and had nontherapeutic INR value (less than 2.0 or greater than 3.0) were included. The data on 688 patients (1,782 visits) requiring dosing adjustment without any known drug or food interaction with warfarin were analyzed. The amount of adjusted dose and INR changes based on the INR at the time of the event were calculated. Aortic valve replacements (AVR) patients and mitral or double valve replacement (MVR/DVR) patients were evaluated separately. Result: Two methods for the warfarin dosage adjustment were suggested: Guideline I (mg-based total weekly dose (TWD) adjustment), Guideline II (percentage-based TWD adjustment). The effectiveness of Guideline 1 was superior to Guideline II overall in patients with both AVR and MVR/DVR. Conclusion: The guideline suggested in this study could be useful when the dosage adjustment of wafarin is necessary in outpatients with mechanical heart valves.

• Journal of Korea Water Resources Association
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• v.37 no.4
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• pp.273-281
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• 2004

Generally, reservoir storage is allocated according to planned purposes established before construction and operating policies are established through release control. The established reservoir allocation is hardly changed unless the special cases such as raising dam or changed purposes occur It Is, however, likely that public needs and objectives can be changed as time go on, the study for multipurpose reservoir storage reallocation is performed as an alternative to reflect these. In this study, flood control analysis is performed for several alternatives of reallocation for the Daechung multi-purpose reservoir in Geum river. As a result, it is confirmed that flood control capability is not decreased compared to single operation of Daechung reservoir for the same flood condition even if conservation level of Daechung multi-purpose reservoir is increased.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.304-308
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• 2005

본 연구에서는 금강유역의 대청다목적댐을 대상으로 대청댐의 제한수위를 변화시켜 가며 대청댐의 홍수조절과 용수공급능력을 판단하였다. 이를 위하여 홍수기 저수지 모의운영 방법 중 Rigid ROM 기법을 수정$\cdot$보완하여 개발한 모의기법을 이용하여 빈도별 홍수유입량에 대해 홍수기 저수지 운영을 실시하였다. 모의운영에 의해 얻은 방류량을 대청댐으로부터 공주지점까지 홍수추적함으로써 공주지점의 최대홍수량을 산정하였다. 산출된 공주지점 최대홍수량을 토대로 대청댐 제한수위의 변화와 빈도별 유입 홍수량의 함수로써 공주지점의 최대홍수량 관계식을 유도하고, 이 관계식을 이용하여 합리적인 대청댐 재할당 수위 및 대청댐 홍수조절 능력을 산정하였다. 또한 대청댐의 상시만수위를 변화시키면서 신뢰도 $95\%$를 만족시키는 용수공급량을 산정하였다. 본 연구의 결과, 홍수조절 측면에서 대청댐의 상시만수위를 78m로 재할당시에 24시간 지속기간을 갖는 300년 빈도 홍수에도 홍수조절이 가능하므로 대청댐의 용량 재할당량은 78m가 적합한 것으로 판단된다. 78m로 재할당 했을 시 이수측면에서 신뢰도 $95\%$를 만족시키는 용수공급량은 기존의 상시만수위 76.5m로 운영했을 시와 비교하여 약 $3\% 증가하는 효과를 얻을 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1460-1465
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• 2005

본 연구에서는 장수형 등(2005)이 제시한 실시간 저수지 유입량 예측모형과 통합하여 하나의 시스템을 구축한 후 하류 하도의 홍수통수능력과 현재 저수지 수위에서 방류 가능량을 고려하여 수문에서의 조절 방류 방안을 제시하였다. 또한, 현재시간 이후로 유입되는 홍수량을 감안하여 강우가 종료되어서도 이수용량이 확보되도록 하였다. 연구는 예당저수지에 적용하였으며, 방류량 계산시 최대 방류가능량은 저수위와 수문의 개도고에 따라 오리피스와 완전월류 흐름을 구분하여 계산하였으며 방류기준은 하류 하도의 통수능력, 강우종료 후 이수용량 확보 등을 감안하여 결정하였다. 연구의 적용결과, 본 연구에서 개발된 저수지 운영시스템을 적용한 결과 강우종료 후에도 이수용량 확보가 가능하였으며, 하류하도의 피해을 최대한 주지 않는 범위 내에서 저수지의 수문조작이 가능하여 예당지의 홍수조절능력을 극대화할 수 있는 방안을 제시하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.39-41
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• 2017

In this letter, we propose a power control mechanism in order to improve secrecy rate defined as the difference between capacity of main link and wiretap link in a wireless multi-cell multiuser network. Through simulations, we verify that the proposed power control mechanism with threshold based user scheduling can significantly increase secrecy rate in a multi-cell environment.

• Korean Journal of Culture and Social Issue
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• v.22 no.1
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• pp.41-64
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• 2016

In two experiments, we compared envy with admiration in attentional and motivational benefits. In addition, we tested whether individual differences in working memory capacity (WMC) have consequences for emotion regulation. In Study 1, following WMC tasks, the participants were primed either with envy or with admiration through a recall task, in which they had to recall their own experiences about envy or admiration. The participants in the envy condition considered it more undeserved that another person had an advantage over them, than in the admiration condition. Additionally, in the envy condition, WMC was related to happiness, and anxiety was related to the motivation to study more. In contrast, there were no significant relationships between WMC, emotion and study hours in the admiration condition. Study 2 (N=43) found greater memory for the envy scenario in the envy condition than in the admiration and in the control condition. Additionally, there were significant relationships between WMC, anxiety and recall accuracy in the envy condition. However, these relations were not found in the admiration and in the control condition. Findings implicate that envy may play an important role in memory systems and that WMC is related to emotion regulation abilities.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.1-10
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• 2007

Reallocation procedure of multipurpose reservoir storage capacity between flood control and conservation is presented as an alternative to secure more water resources. Storage reallocation is an adaptive management mechanism for converting existing normal pool level of reservoirs to more beneficial uses without requirement for physical alteration. This study is intended to develop a reservoir storage reallocation methodology that allows increased water supply storage without minimizing adverse impacts on flood control. The methodology consists of flood control reservoir simulation for inflows with various return periods, flow routing from reservoir to a potential damage site, analyzing river carrying capacity, and reservoir yields estimation for reallocated storages. For the flood control model, a simulation model called Rigid ROM(Reservoir Operation Method) and HEC-5 are used. The approach is illustrated by applying it to two reservoirs system in Geum River basin. Especially with and without new project conditions are considered to analyze trade-offs between competing objectives.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.740-745
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• 2006

최근 중 소규모의 도시개발, 택지개발, 유통단지, 산업단지, 주택단지 조성 등의 단지개발이 급속히 증가하고 있으며, 이에 따라 재해영향평가 및 사전재해영향성 검토도 증가하고 있는 실정이다. 단지개발은 보통 지구지정 또는 기본계획을 수립하여 개발계획 승인을 받고 실시설계를 통하여 실시계획을 승인을 받는 절차를 갖는다. 이에 효율적인 토지이용계획을 위하여 개발계획 승인전에 수십 회의 토지이용을 변경하고 또한 실시계획승인 전에도 토지이용계획은 수회의 변경을 통하여 이루어진다. 이에 재해영향평가 및 사전재해영향성검토를 초기단계에서 수행하는 실무자들은 토지이용계획의 빈번한 변경으로 인하여 저류지 규모 산정에 어려움을 가지고 있다. 단지개발의 토지이용계획 특성상 투수지역이 다소 있는 단지, 투수지역인 공원 녹지, 불투층인 도로 주차장으로 주로 구성된다는 공통점이 있다. 따라서 최근의 심의 완료된 재해영향평가보고서들을 인용, 각 단지개발의 토지이용계획도를 고려한 저류지 홍수조절용량을 산정하는 경험적이고 통계적인 다중회귀모형을 개발하였다. 금회 유도된 다중회귀모형식은 재해영향평가 및 사전재해영향성검토를 수행하는 실무자에게 행정계획단계뿐만 아니라 개발사업단계에서도 신속하게 저류지 규모를 개략 산정하고, 비전문가인 검토자가 신속히 홍수조절용량의 적정성을 검토하는데 매우 효과적으로 사용될 것으로 판단된다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.3
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• pp.258-266
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• 2000

Experimental investigation and cycle simulation of a capacity modulation of a heat pump system using a hydrofluorocarbon (HFC) refrigerant mixture, R32/134a as an alternative to R22, have been done. In the cycle simulation, the refrigeration system was operated by assigning the temperatures of the external heat transfer fluids with the heat exchangers generalized by an average effective temperature difference. Heating capacity, cooling capacity, and coefficient of performance (COP) of the system were investigated at several operating conditions. Experimental apparatus which had a refrigeration part and a composition changing part was built, and the performance of the heat pump system filled with R32/134a mixture was investigated. A gas-liquid separator was used in the experiment to change the composition by collecting the vapor and the liquid Phase separately, The mass fraction of the charged refrigerant in the heat pump system was 40/60 and 70/30 by weight percentage. The composition of the refrigerant with initial composition of 40/60 varied from 29/71 to 41/59 in the refrigeration cycle. For the refrigerant with initial composition of 70/30, the composition varied from 65/35 to 75/25.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.5
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• pp.446-475
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• 2000

Performance of a water-to-water multi-type heat pump system using R22 has been experimentally investigated. Total refrigerant flow rate was adjusted with a variable speed compressor and the refrigerant flow rate for two indoor units were controlled by electronic expansion valves. Evaporator outlet pressure of refrigerant and indoor unit outlet temperatures of secondary fluid were selected as controlled variables. Experiments were carried out for both cooling and heating modes using PID control method. Results show that the multi-type heat pump system can be adequately controlled by keeping control gains at certain levels for various operating conditions.