• 전기학회논문지
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• 제59권10호
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• pp.1741-1747
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• 2010

The development of overload management systems for distribution transformers offers new opportunities for improving the reliability of distribution systems. It allows network planners to optimize the system resource utilization and investment cost. Such an improvement in the flexibility of the distribution network is only possible if the operator has more accurate knowledge of the realtime conditions of distribution transformers. In this paper, we present an improved overload decision system for distribution transformers using realtime monitoring data. Our study can be categorized into two parts: (a) improvement in the criteria for judging the overload conditions of distribution transformers and (b) development of an overload evaluation system using realtime monitoring data. In order to determine the overload criteria, overload experiments are performed on sample transformers; the results of these experiments are used to define the relationship between the transformer overload and the increase in the top-oil temperature. To verify the accuracy of the experimental results, field tests are performed using specially manufactured transformers, the loads and top-oil temperatures of which can be measured. For arriving at online overload decisions, we propose methods whereby the measured load curve can be converted into an overload characteristic curve and the overload time can be calculated for any load condition. The developed system is able to evaluate the overload for individual distribution transformers and calculate the losses using realtime monitoring data.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.88-90
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• 2003

We implement Realtime Air Diffusion Prediction System which is designed for air diffusion simulations with four-dimensional data assimilation. For realtime running, we parallelize the system using MPI (Message Passing Interface) on distributed-memory parallel computers and build a cluster computer which links high-performance PCs with high-speed interconnection networks. We use 162­CPU nodes and a Myrinet network for the cluster

• 한국통신학회논문지
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• 제28권9A호
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• pp.736-745
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• 2003

본 논문은 CDMA/TDD 시스템에서, 높은 전송률과 일정한 QoS를 갖는 실시간 클래스의 무선 자원 할당에 대한 방법론을 제시한다. 실시간 클래스와 비실시간 클래스를 제어하기 위하여, 예약 액세스 기법과 우선 순위 기법이 각각 제안된다. 또한 각 셀 링크간 간섭에 의한 성능 감소를 예방하기 위하여 슬롯 할당 기법을 제안한다. 제시된 방안들을 통하여 실시간 클래스의 연속성을 보장하고 비실시간 가입자를 최대로 수용할 수 있다. 다중 셀 환경과 멀티미디어 서비스 모델을 가정하여, 제안된 기법의 성능이 전송 지연, 채널 이용률 그리고 데이터 손실 등을 근거로 하여 평가된다. 시뮬레이션 결과는 상당한 성능 향상이 있음을 보인다.

• 한국콘텐츠학회논문지
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• 제19권2호
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• pp.460-468
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• 2019

최근 빅데이터 분석을 통해 새로운 정보들을 도출해내기 위한 분석 기법들과 이를 이용한 다양한 서비스들이 개발되고 있다. 그 중에서 빅데이터가 중요하게 활용될 수 있는 분야 중의 하나가 교통 분야이다. 기존 대중교통 안내 서비스의 경우 현재 교통정보를 기준으로 추천하기 때문에 실제로는 최적이 아닌 경로가 추천될 수 있다. 본 논문에서는 빅데이터 분석을 통한 실시간 최적 교통 경로 안내 시스템을 설계하고 구현한다. 설계한 시스템은 실시간 교통정보를 활용함과 동시에 과거 수집된 교통 정보를 분석하여 각 경로들의 교통 상황을 예측하여 경로 이동 계획을 설정해준다. 또한 중간에 교통상황이 급변하여 경로를 수정해야할 필요가 있을 때 사용자에게 알림을 주고 그에 대한 조치를 취할 수 있도록 지원한다.

• 한국멀티미디어학회논문지
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• 제21권5호
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• pp.599-608
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• 2018

As natural disasters are increasing due to the unusual weather and the modern society is getting complicated, the rapid change of the urban environment has increased human disasters. Thus, citizens are becoming more anxious about social safety. The importance of preparation for safety has been suggested by providing the disaster safety services such as regional safety index, life safety map, and disaster safety portal application. In this paper, we propose an application framework to predict the urban safety index based on user's location with realtime weather/atmosphere data after creating a predication model based on the machine learning using number of occurrence cases and weather/atmosphere history data. Also, we implement an application to provide traffic safety index with executing preprocessing occurrence cases of traffic and weather/atmosphere data. The existing regional safety index, which is displayed on the Si-gun-gu area, has been mainly utilized to establish safety plans for districts vulnerable to national policies on safety. The proposed system has an advantage to service useful information to citizens by providing urban safety index based on location of interests and current position with realtime related data.

• 한국멀티미디어학회논문지
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• 제19권4호
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• pp.689-705
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• 2016

This paper proposed an realtime total monitoring platform for various kind of multi weather radars to analyze and predict weather phenomenons and prevent meteorological disasters. Our platform is designed to process each weather radar data on each radar site to minimize overloads from conversion and transmission of large volumed radar data, and to set observers up the definitive radar data via public framework server separately. By proposed method, weather radar data having different spatial or temporal resolutions can be automatically synchronized with there own spatio-temporal domains on public GIS platform having only one spatio-temporal criterion. Simulation result shows that our method facilitates the realtime weather monitoring from weather radars having various spatio-temporal resolutions without other data synchronization or assimilation processes. Moreover, since this platform doesn't require some additional computer equipments or high-technical mechanisms it has economic efficiency for it's systemic constructions.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1997년도 International Conference MULTIMEDIA DATABASES on INTERNET
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• pp.319-334
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• 1997

불과 2년 전만 하더라도 인터넷에서 오디오 또는 비디오 데이터를 감상하기까지 일련의 과정은 그 데이터의 물리적인 양과 전달방식에 있어서 이용자들에게 많은 인내력을 요구해 왔다. 이에 대한 해결책으로 관련업계에서는 real-time streaming 기술을 도입하여 각종 비디오와 오디오 데이터 전송에 관련기술을 적용시킴으로서 실시간 비디오/오디오 서비스 이용을 용이하게 하려는 움직임이 활발히 진행되어 왔었다.(중략)

• 산업공학
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• 제16권2호
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• pp.258-267
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• 2003

Recently, virtual reality technologies have been rapidly developed and realtime virtual simulation methods have been extensively employed for several application areas such as game, sports, manufacturing, military, and so on. A 3D database in realtime virtual simulation plays a key role because it makes users feel reality in virtual space. In a application view of 3D database, a systematic construction approach is required to reduce its construction time and increase its quality. However, many researches have been mostly focused on realtime graphic issues and its key technologies. In virtual simulation of transportation equipments, this paper proposes a systematic construction process of 3D database consisting of four stages as follows: 1) determine the activity space of a equipment, 2) collect data related to 3D database construction, 3) make a 3-dimensional modeling strategy, and 4) generate and evaluate a 3D model. This paper also introduces a new procedure of 3D environment modeling, which summarizes and expands our modeling experiences, to be used as a modeling guide.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.77-80
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• 2010

The demand for human security significantly promotes the development of surveillance applications using a multi-sensor integrated UAV system. For more sophisticated operations, the system should provide a sequence of images rectified in a ground coordinate system in realtime. This rectification requires accurate position and attitude of the camera at the time of exposure of each image, which can be estimated through an Aerial Triangulation process using the GPS/INS data and tie points between adjacent images. In this work, the KLT tracker is utilized to obtain the tie points. To satisfy the realtime requirements, we present an approach to speed up the tracker by supplying the initial guessed positions of tie points based on the exterior orientation. The experimental results show that, when the guessed positions are supplied, the KLT tracker consumed less computational time than the ordinary KLT which is more suitable to be incorporated into the realtime image georeferencing process.

• 한국군사과학기술학회지
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• 제12권1호
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• pp.29-36
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• 2009

Realtime tide and storm-surge computations for the Yellow Sea were conducted using the Parallel Finite Element Model. For these computations a high resolution grid system was constructed with a minimum node interval of loom in Gyeonggi Bay. In the modeling, eight main tidal constituents were analyzed and their results agreed well with the observed data. The realtime tide computation with the eight main tidal constituents and the storm-surge simulation for Typhoon Sarah(1959) were also conducted using parallel computing system of MPI-based LINUX clusters. The result showed a good performance in simulating Typhoon Sarah and reducing the computation time.