• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.257-257
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• 2017

본 연구는 기상이변의 영향으로 지속적으로 발생되고 있는 댐 저수지 붕괴에 대한 원인 분석과 기존의 관련 연구 및 지침 등을 비교 분석하여 현재 실무에서 적용되고 있는 댐 저수지 비상대처계획(EAP) 수립 대상 기준에서 제외되는 시설물의 붕괴 가능성 평가를 통해 EAP 수립 대상의 적정 범위를 제시하고자 하였다. 이를 위해 본 연구에서는 시설물의 붕괴 가능성에 대한 정량적 판단 기준을 각 요인별로 제시하고, EAP 수립 대상에서 제외되는 댐 저수지를 대상으로 붕괴 가능요인을 적용하여 3개 이하의 붕괴요인에 해당될 경우 저위험군, 4개 및 5개의 붕괴요인에 해당될 경우 중위험군과 고위험군으로 각각 분류하여 시설물 붕괴 위험성 정도에 따른 적절한 대응이 이루어질 수 있도록 제안하였다. 댐 저수지 붕괴 사례 분석을 통해 도출된 붕괴 가능성의 주요 요인으로는 저수용량, 제체 높이, 준공 경과연수, 우심피해 및 지진피해 잠재지역이 포함되며, 각 요인별 객관적인 판단기준은 댐 저수용량의 경우 EAP 법적 수립기준 및 과거 붕괴사례 등의 분석을 토대로 붕괴사례 61개소 중에서 약 88%를 차지하는 저수용량 10만톤을 선정하였으며, 댐 높이의 경우 댐의 파괴양상(이종태, 1987)에서 제시한 댐 붕괴부 특성과 미국주댐안전협회(ASDSO: American Society of Dam Safety Official) 학술지인 Dam Safety(2006) 등에서 제안한 기준을 기존의 댐?저수지 붕괴사례에 적용하여 댐 붕괴폭과 댐 높이의 상관관계 분석 결과를 바탕으로 댐 높이 8m 이상을 적정 범위로 고려하였다. 준공 경과연수의 경우에는 국민안전처 "재해위험저수지 댐 관리 지침" 타당성 평가기준인 '시설노후도' 기준과 한국시설안전공단 사회간접자본 노후화 기준에 해당하는 경과연수 기준을 토대로 30년 이상을 기준으로 선정하였으며, 우심피해 및 지진피해 잠재지역은 국민안전처 재해연보(2014)를 기준으로 과거 10년 동안의 우심피해 발생 지역과 기상청 국내 지진 규모 10위권 내에 포함되는 지역을 고려 대상으로 하였다. 본 연구에서 도출한 시설물 붕괴 가능성에 대한 판단기준을 국민안전처에서 고시한 EAP 수립 대상에서 제외되는 지자체 재해위험저수지 354개소에 적용해 본 결과, 저위험군 16개소, 중위험군 5개소, 고위험군 2개소로 각각 조사되었다. 저위험군은 전문 시설물 관리자에 의한 주기적인 시설물 점검 및 관찰이 필요할 것으로 사료되며, 중 고위험군에 속하는 시설물의 경우 본 연구의 결과를 바탕으로 시설물 하류지역의 실질적인 인명 및 경제적 피해 가능성에 대한 보다 면밀한 조사를 통해 EAP 수립 대상 포함여부를 결정하여야 할 것으로 판단된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.1009-1016
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• 2015

In this paper, we propose EPCM(Efficient Prediction-based Context-awareness Matrix) algorithm analyzing connectivity by predicting cluster's context data such as velocity and direction. In the existing DTN, unrestricted relay node selection causes an increase of delay and packet loss. The overhead is occurred by limited storage and capability. Therefore, we propose the EPCM algorithm analyzing predicted context data using context matrix and adaptive revision weight, and selecting relay node by considering connectivity between cluster and base station. The proposed algorithm saves context data to the context matrix and analyzes context according to variation and predicts context data after revision from adaptive revision weight. From the simulation results, the EPCM algorithm provides the high packet delivery ratio by selecting relay node according to predicted context data matrix.

• Journal of the Society of Disaster Information
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• v.8 no.1
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• pp.71-80
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• 2012

It is necessary to establish guidelines when we selecting the civil defense evacuation facilities through quantitative analysis by civil defense evacuation facilities volume. The purpose of this study is to evaluate according to population density and distribution of the capacity of evacuation facilities. The results of this study are as follows. First, it is necessary to consider the capacity of evacuation facilities in order to set up the exact districts of civil defense evacuation facilities. Second, basic data based on to compare the condition of civil defense evacuation facilities is produced by an analysis on evacuation status of the target region. Third, it is proved to consider topographical conditions which do not move the shortest distance. Fourth, in order to create a realistic model, it is necessary to consider the model set various parameters.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.295-309
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• 2019

This paper demonstrates that the verification and analysis of the increase of hosting capacity of distributed energy resources in distribution system for the high penetration of distributed energy resources. In the case of generally designed distribution feeders in South Korea, it can host up to 10 MVA of distributed energy resources and the over voltage due to reverse power flow is prohibited beyond the range by the law of electric utility. However, it should take into consideration that there are some factors of extra hosting capacity such as generation characteristics of distributed energy resources and minimum loads that always exist to distribution system. For these reason, we choose a specific distribution system hosted 10 MVA of distributed energy resources monitored by distribution system operator and verify the impact of increasing hosting capacity such as power flow and voltage profile of distribution system. By the result, we could find that it is possible to increase the hosting capacity and define the factors to expand the hosting capacity of distributed energy resources in distribution system.

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.31-38
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• 2011

In this study, we investigate simulation studies to confirm the removal of smoke through ventilation when the subway car is on fire and stopped in an underground subway tunnel, by using Fire Dynamics Simulator (FDS) which is being upgraded by NIST. The structure of subway tunnel and train for simulation modeling are based actual data from Seoul metropolitan subway. The main purpose of this study is to assure the removal efficiency of the ventilation when changing the ventilation capacity between 2.0 m/s and 3.0 m/s. The results of the study shows that carbon monoxide (CO) and carbon dioxide ($CO_2$) are reduced by about 35% as the ventilation capacity is increased by 0.5 m/s. This study also performs the grid sensitivity verification of FDS for improved accuracy of the results. To find the effective size of the grid, three cases are simulated and the results are compared.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.1
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• pp.44-49
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• 2012

The indirect-contact ECG measurement is a newly developed method for unconstrained and nonconscious measurement in daily Life. This study is the first step to reducing the large background noise appearing in indirect-contact ECG. This study built the thermal noise model of capacitively coupled active electrode which is used in indirect-contact ECG. The results show that the level of thermal noise estimated by the thermal noise model is much the same as that of actual background noise for the capacitively coupled active electrode alone. By applying the actual electrical properties of a sample cotton cloth to the thermal noise model, the theoretical level of thermal noise in the indirect-contact ECG was estimated. The results also show that the level of op-amp's intrinsic noise is so small that it can be negligible in comparison with thermal noise of resistors. The relationship between the level of thermal noise and the resistance of the bias resistor was derived, and it is the base for the further study how to choice the optimal resistance for the bias resistor.

• Tunnel and Underground Space
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• v.24 no.1
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• pp.1-10
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• 2014

This paper presents a case study that performed simulations on shovel-truck haulage systems in an open-pit mine by considering truck's breakdown and crusher's capacity. The SSangyoung limestone open-pit mine in Korea was selected as a study area and investigated to design the simulation algorithms. The GPSS/H simulation language is used to implement the simulation algorithms as a console application(simulator). The values of input parameters for simulator were measured by field investigation in the study area. The simulation results showed that 7 trucks can maximize the daily profit of haulage operations(i.e., 73,775 USD) when considers the frequency of trucks' breakdown as 1/40 $hour^{-1}$. In addition, the crusher capacity of 1300 tph is required to improve the efficiency of shovel-truck haulage systems in the study area.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.77-84
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• 2007

It is increased electrical energy consumption with the development of intelligence society in hospitals and thus an energy conservation through efficient use of electricity became more important. This paper shows a reasonable design demand factor in hospitals, that was made by the systematic and statistical way considering actual conditions, such as investigated electric equipment capacity, peak power consumption, demand factor, etc., for 32 hospitals and 9 electrical design offices. In this dissertation, it is necessary to analyze the key features and general trend from the investigated data. It made an analysis of the feature parameters, such as average, standard deviation, median, maximum, minimun and thus it was carried the linear and nonlinear regression analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5457-5463
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• 2011

The objective of this study is to investigate cooling performance characteristics of mobile air conditioning system using R744 as an alternative of R-134a. In order to analyze the cooling performance characteristics of the air conditioning system using R744 for a passenger vehicle, the developed air conditioning system using R744 was applied in a real passenger vehicle and tested under various operating conditions with the variation of gas-cooler inlet air conditions, evaporator inlet air temperatures and compressor speeds. As a result, cooling capacity and coefficient of performance (COP) of the tested air conditioning system decreased with the rise of the inlet air temperature of the gas cooler but increased with the rise of the inlet air temperature of the evaporator. In addition, cooling capacity and coefficient of performance (COP) increased by 42.2 % with the rise of the compressor speed from 900 rev/min to 1800 rev/min, but it decreased by 55.4%.

• Journal of Korea Water Resources Association
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• v.52 no.4
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• pp.291-300
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• 2019

If pipes are damaged in a water distribution network (WDN), adjacent valves are closed to isolate the pipes for repair. Due to the closed valves, parts of WDN are isolated from water supply sources. The isolated area is divided into Intended Isolation Area (IIA) and Unintended Isolation Area (UIA). The IIA occurs by intention to isolate the damaged pipe, while UIA is unintentionally disconnected from the sources due to IIA. Thus, the extension of isolated area and suspended flows are mainly affected by number and location of installed valves in WDN. In this study, optimization models were developed to determine optimal valve locations in WDN. In a single-objective model, total water supply suspension is minimized, while a multi-objective model intends to simultaneously minimize the suspended flow and valve installation cost. Optimal valve placement results obtained from both models were compared and analyzed using a sample application network.