• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.475-477
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• 1999

최근 지하공간에서 체류하는 시간이 점차 증가됨에 따라 지하공간상의 특성상 지하공간내 실내공기오염에 따른 위해성에 대한 논의가 계속되고 있다. 지하공간으로 대표적인 지하철 역사의 경우 근무자들이 노출되는 NO$_2$를 포함한 여러 가지 실내공기오염물질들이 역사에 설치된 각종 공조설비의 운영이 적절치 못할 경우 근무자들 뿐만 아니라 지하철 이용 승객들에게도 건강상 악영향을 미칠 우려가 있으므로 그 실태 파악이 요구된다.(중략)

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.334-336
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• 2002

본 논문에서는 스타그래프 다중처리시스템을 위한 새로운 프로세서 할당방범을 제안한다. 기존의 할당방법은 프로세서 단편화로 인해 작업을 처리할 서브스타를 형성하지 못하면 프로세서 할당이 지연되는 문제점이 있었다. 이러한 할당 지연은 작업의 대기시간을 증가시키고 시스템의 성능 향상을 제한한다. 본 논문에서 제안하는 할당방법은 프로세서 할당 지연이 발생하면 동적할당테이블을 사용하여 단편화된 프로세서의 주소론 재생성한다. 새로운 주소의 프로세서들로 가용 서브스타를 형성하여 할당함으로써 작업의 대기시간을 줄이고 프로세서 단편화를 최소화한다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.611-616
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• 1996

원자력 발전소에서 대기중으로 방출된 방사성 물질의 이동 양태는 지형과 기상조건에 의해 크게 좌우되므로, 해안가에 위치해 있는 월성부지의 경우는 빈번히 발생하는 해륙풍 특성을 규명하여 이에 적합한 환경영향평가 및 비상대응체제를 구축해야 한다. 월성부지의 해륙풍 순환구조를 파악하기 위해 봄철 해륙풍 상층기상 특별관측을 월성부지를 중심으로 4개 지점에서 실시하였다. 관측결과를 분석하여 해륙풍이 방사성 물질의 대기확산에 미치는 영향을 분석하고, 해륙풍을 반영할 수 있는 새로운 환경영향평가 방법론을 고찰하였다.

• Digital Contents
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• no.12 s.139
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• pp.62-67
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• 2004

창립 10주년을 넘어서는 디지털콘텐츠 기업이 늘고 있다. 10년이면 강산도 변한다고 했다. 수많은 디지털콘텐츠 기업들이 무대에서 사라지 기도 했고, 대기업 못지 않은 부를 축적한 기업도 생겨났다. 벤처신화, 벤처 게이트, 닷컴거품론, 닷컴부활론 등 사회를 떠들석하게 했던 일 련의 사건과 논쟁 또한 디지털콘텐츠와 무관치 않았다. 이제 국내 디지털콘텐츠 산업은 새로운 도전을 준비해야 한다는 게 업계의 지적이다. 국내 디지털콘테츠 기업들의 변화와 과제를 살펴봤다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.663-669
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• 2011

In this study, the optimal length of left-turn lane in permissive left-turn signal system at the signalized intersection which has a left-turn bay is estimated. It is a simulation analysis using the queueing theory that estimate the length of left-turn lane. Traffic density conform to the standards of operating a permissive left-turn system of the Practical Manual Traffic Safety Facilities. And each of a left-turn arrival rate, a left-turn service rate, left-turn average queueing time, for green time average queueing vehicle, for red time average queueing vehicle and average queueing vehicle cycle is calculated. As a result of this study, we would learn how much the space should be secured at the signalized intersection which has a left-turn bay. The methodology using the queueing theory to work out the optimal length of waiting lane in the permissive left-turn signal system was presented.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1679-1692
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• 2023

South Korea is a country that emits a large amount of pollutants as a result of population growth and industrial development and is also severely affected by transboundary air pollution due to its geographical location. As pollutants from both domestic and foreign sources contribute to air pollution in Korea, the location of air pollutant emission sources is crucial for understanding the movement and distribution of pollutants in the atmosphere and establishing national-level air pollution management and response strategies. Based on this background, this study aims to effectively acquire spatial information on domestic and international air pollutant emission sources, which is essential for analyzing air pollution status, by utilizing high-resolution optical satellite images and deep learning-based image segmentation models. In particular, industrial parks and quarries, which have been evaluated as contributing significantly to transboundary air pollution, were selected as the main research subjects, and images of these areas from multi-purpose satellites 3 and 3A were collected, preprocessed, and converted into input and label data for model training. As a result of training the U-Net model using this data, the overall accuracy of 0.8484 and mean Intersection over Union (mIoU) of 0.6490 were achieved, and the predicted maps showed significant results in extracting object boundaries more accurately than the label data created by course annotations.

• Journal of the Korea Society for Simulation
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• v.23 no.3
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• pp.1-9
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• 2014

Traditional workflow time analyses have been performed treating an activity as an independent M/M/1queueing system. Using the general forms of performance measures in the M/M/1 system, various aspects of analyses can be performed. Especially, on the time analysis of an AND structure in a workflow system, the mean system sojourn time can be formalized by applying the performance measures of M/M/1 system. In the real workflow system, the AND structure cannot be described correctly under the assumption of independent M/M/1 systems. To overcome this limitation, this research makes the assumption that the all activities for a task starts simultaneously. In this situation, the theoretical solution can be derived using the performance measures of the M/G/1 system. In addition, the simulation modeling method will be proposed to analyze the AND structure of a real workflow system. Finally, some numerical results from the theoretical solutions and simulation models will be provided for verification. The main performance measures used in this research are mean queueing time and mean sojourn time.

• Atmosphere
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• v.28 no.4
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• pp.443-455
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• 2018

Nowcasting algorithms using weather radar data are mostly based on extrapolating the radar echoes. We estimate the echo motion vectors that are used to extrapolate the echo properly. Therefore, understanding the general characteristics of these motion vectors is important to improve the performance of nowcasting. General characteristics of radar-based motions are analyzed for warm season precipitation over Jeju region. Three-year summer season data (June~August, 2011~2013) from two radars (GSN, SSP) in Jeju are used to obtain echo motion vectors that are retrieved by Variational Echo Tracking (VET) method which is widely used in nowcasting. The highest frequency occurs in precipitation motion toward east-northeast with the speed of $15{\sim}16m\;s^{-1}$ during the warm season. Precipitation system moves faster and eastward in June-July while it moves slower and northeastward in August. The maximum frequency of speed appears in $10{\sim}20m\;s^{-1}$ and $5{\sim}10m\;s^{-1}$ in June~July and August respectively while average speed is about $14{\sim}15m\;s^{-1}$ in June~July and $8m\;s^{-1}$ in August. In addition, the direction of precipitation motion is highly variable in time in August. The speed of motion in Lee side of the island is smaller than that of the windward side.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1155-1160
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• 1999

The screening methodology modeling, dispersion modeling procedures for continuous and instantaneous releases of the gas phase flow from the storage tank and pressure relief valve were considered. This study was performed to develop the screening methodology for prediction and control of hazardous/toxic gas releases by estimating the 1-hr average maximum ground-level concentration of $Cl_2$ gas vs. downwind distance by incorporating source term model including the general/physical properties of released material and release mode of the $Cl_2$ storage tank of the chemical plant facilities, dispersion model, and meteorological/topographical data into the TSCREEN model. As the results of the study, it was found that dispersion modes of the dense gas were affected by the state of the released material, the released conditions, physical-chemical properties of released material, and the released modes (continuous and instantaneous releases), and especially largely affected by initial (depressurized) density of the released material and release emission rate as well as the wind velocity. Especially, this study was considered to release hazardous material as meteorological data. It was thought that this screening methodology can be useful as a preliminary guideline for application of the refined analysis model by developing the generic sliding scale methodology for various senarios selected.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1087-1094
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• 2013

This study aims at enhancing the objective estimation of social cost of air quality due to mobile emission. More specifically, it examines the difference between the daily oriented and hourly oriented estimation results of social air quality cost and draws implications from the comparative analysis. The result indicates that the social cost of air quality differs up to approximately 24 times depending on the analysis time period. Moneywise, the difference between daily and hourly assignments amounts to the average of 653.5 billion won whereas only 1% of error occurred in the estimation result based on peak and nonpeak based hourly assignment. This study reaffirms the need for time-based travel demand management for emission reduction, and confirms the feasibility of emission estimation by travel demand forecasting method over the conventional method employed by the CAPSS.