• 지능정보연구
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• 제3권1호
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• pp.31-45
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• 1997

To date, research on data mining has focused primarily on individual techniques to su, pp.rt knowledge discovery. However, the integration of elementary learning techniques offers a promising strategy for challenging a, pp.ications such as forecasting nonlinear processes. This paper explores the utility of an integrated a, pp.oach which utilizes a second-order learning process. The a, pp.oach is compared against individual techniques relating to a neural network, case based reasoning, and induction. In the interest of concreteness, the concepts are presented through a case study involving the prediction of network traffic for video-on-demand.

• 한국경영과학회지
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• 제23권3호
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• pp.49-62
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• 1998

In the ring loading problem, traffic demands are given for each pair of nodes in an undirected ring network with n nodes and a flow is routed in either of the two directions, clockwise and counter-clockwise. The load of a link is the sum of the flows routed through the link and the objective of the Problem is to minimize the maximum load on the ring. In the ring loading problem with integer demand splitting, each demand can be split between the two directions and the flow routed in each direction is restricted to integers. Recently, Vachani et al. ［INFORMS J. Computing 8 (1996) 235-242］ have developed an Ο(n$^3$) algorithm for solving this integer version of the ring loading problem and independently, Schrijver et al. ［to appear in SIAM J. Disc. Math.］ have presented an algorithm which solves the problem with ｛0,1｝ demands in Ο（n$^2$｜K｜ ) time where K denotes the index set of the origin-desㅇtination pairs of nodes having flow demands. In this paper, we develop an algorithm which solves the problem in Ο(n ｜K｜) time.

• 한국위험물학회지
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• 제6권2호
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• pp.68-76
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• 2018

This study aims to provide a methodological framework to estimate the travel demand of hazardous materials transporting vehicles by link and analyze daily traffic patterns on an expressway to develop safety roadway management strategies. Traffic volume of hazardous material vehicles is counted through the on-site investigation at twenty-five tollgates on the expressway, and their demands by a link are predicted through origin-destination flows estimation. The result shows that the number of the domestic hazardous materials vehicles is approximately 51,207 vehicles per day and it indicates that hazardous materials transport vehicles account for 1.5% of total daily traffic on the internal expressway and 6.2% of total cargo traffic volumes. This study roughly estimated how many hazardous materials vehicles pass through the expressway segment. Thus it is expected to be utilized for establishing a systematic highway management strategy in the future by calculating the traffic volume of the hazardous material vehicles traveling on the interstate expressway.

• 한국항만학회지
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• 제8권1호
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• pp.3-15
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• 1994

Most of Cities are suffering from the traffic congestion problem with the vehicles increased. Especially, the City of Pusan is experiencing the severest traffic congestion with the lower read capacity and the higher travel demand than any other cities in the country. Thus, the purpose of this study was to grasp the conditions, review the problems and finally suggest the improvements which we faced at this time for the construction of the Urban Transportation System considered in Pusan area. Based upon the results, it was concluded that firstly the Urban Transportation System(UTS) in Pusan area should be constructed by the Public Transportation System in the center of the Public Transit Modes(i.e., bus and subway), secondly the Para-transit Modes(i.e., Light Rail Transit, LRT) introduced, and thirdly the Transportation Demand Management(TDM) implemented with the expansion of the transportation facilities if possible.

• 한국항공운항학회지
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• 제29권4호
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• pp.124-133
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• 2021

The airline industry has been growing steadily since 2016 with more than 100 million air passengers, renewing the largest number of air passengers every year. Increasing air demand leads to an increase in air traffic in limited airspace, increasing the likelihood of accidents between aircraft. Due to the massive human and material damage caused by a single mistake, aviation safety is being heavily focused around the world to efficiently use limited airspace. Studies related to various human factors are underway as most of the aviation accidents are found to be caused by human factors, but research on human factors by controllers is insufficient while they are active in terms of control and operation. Given that 82% of air accidents caused by controllers are caused by human error, the importance of management of human error and changes in perception are urgently needed. This study aims to understand the seriousness of the controller's human error by analyzing the accident cases caused by the controller's human error using TEM to identify threats and errors and derive common human factors.

• 대한교통학회지
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• 제19권4호
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• pp.97-108
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• 2001

기존의 동적 통행배정모형은 출발시간 선택에 있어서 도착시간제약을 고려하지 못하고 있으며, 이를 고려하더라도 수단분담을 고려하지 못하거나 별도의 문제로 다루고 있다. 따라서 대중교통의 수단분담비가 높고, 도착시간에 대한 제약이 따르는 출근·통학통행이 주류를 이루는 오전첨두시의 교통관리·분석을 위해서는 이들을 동시에 고려하는 동적 통행배정모형이 요구된다. 본 연구에서는 Ran과 Boyce가 구축한 모형에 기반하여 통행수단과 도착시간 제약에 따른 출발시간 선택을 경로선택과 동시에 고려할 수 있는 통합모형을 제시하였다. 모형의 풀이를 위해 Ran과 Boyce가 사용한 시·공간 확장 가로망을 새롭게 설계하여 사용하였으며, 가상 가로망에 적용하여 모형의 적합성을 검증하였다. 사례연구 결과 본 연구에서 제시한 모형이 동적 사용자최적 통행배점상태를 나타내는 것을 확인할 수 있었고, 이를 통해 오전 첨두시의 교통관리·분석을 위해 적용 가능함을 입증하였다.

• 한국정보처리학회논문지
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• 제5권1호
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• pp.161-171
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• 1998

본 논문은 웹 서버의 트래픽 관리를 위하여 성능 파라미터를 정의하고 이를 분석하기 위한 관리자 시스템을 웹 기술과 JAVA 기술을 이용하여 구현함으로써 웹 서비스를 모니터링하고 웹 서버의 성능을 관리하고자 하였다. 현재 웹 상에서의 트래픽 관리가 웹 성장에 의한 웹 트리팩의 증대로 그 필요성이 대두됨에 따라, 웹 서비스 트래픽 관리와 웹 서버 성능에 대한 효율적인 관리가 필요하게 되었다. 이를 위해 네트워크 상의 임의의 호스트에 성능 관리자 시스템을 위한 클라이언트를 구현하여 사용자로 하여금 수집 요구와 분석 요구, 실시간 모니터링, 그리고 비교 분석 요구 등을 t할 수 있는 인터페이스를 설계하고, 이러한 요구를 분석하는 서버 시스템을 구현하였다. 또한 기존의 MIB을 사용하여 각 분석 항목에 맞게 HTTP 메시지량과 바이트량 분석, 연결 수 분석, 입출력 트래픽 비교 분석 등과 같은 새로운 성능 파라미터를 정의하였다. 아울러, 웹 클라이언트-서버 시스템간의 통신을 위해 새로운 메시지 형식을 정의하고 구현하였다. 따라서 웹 서버 시스템의 운영과 관리 시 성능에 따른 문제점을 발견하고 해결을 지원하는데기여할 수 있다.

• 디지털콘텐츠학회 논문지
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• 제13권3호
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• pp.469-476
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• 2012

최근 스마트폰, 스마트패드 등 스마트기기의 보급이 보편화되면서 스마트기기의 이용자 수가 폭발적으로 증가하고 있다. 이에 따라 모바일 인터넷 트래픽도 급증하고 있는 추세이며, 이러한 모바일 인터넷 트래픽의 수요는 전세계적으로 해마다 기하급수적으로 증가될 것으로 예측되고 있다. 이에 발맞추어 국내외적으로 이동통신 사업자들은 이를 효과적으로 해결하기 위해 많은 노력과 투자를 기울이고 있으며, 급증하고 있는 모바일 인터넷 트래픽을 보다 효율적으로 분산시키기 위한 망(network) 기반(즉, PMIPv6기반) 분산형 이동성 관리 기술에 대한 관심은 날로 커져만 가고 있는 실정이다. 본 논문에서는 이러한 PMIPv6 기반 분산형 이동성 관리 기술의 개요 및 최신 연구동향을 살펴보고, 아울러 PMIPv6 기반 분산형 이동성 관리 기술 연구에 대한 필요성 및 향후 전망에 대하여 기술한다.

• 산업공학
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• 제18권3호
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• pp.333-342
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• 2005

In this paper, we propose an efficient forecasting methodology of the mid and long-term frequency demand in Korea. The methodology consists of the following three steps: classification of basic service group, calculation of effective traffic, and frequency forecasting. Based on the previous studies, we classify the services into wide area mobile, short range radio, fixed wireless access and digital video broadcasting in the step of the classification of basic service group. For the calculation of effective traffic, we use the measures of erlang and bps. The step of the calculation of effective traffic classifies the user and basic application, and evaluates the effective traffic. Finally, in the step of frequency forecasting, different methodology will be proposed for each service group and its applications are presented.

• 대한산업공학회지
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• 제29권2호
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• pp.135-144
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• 2003

Traffic performance in a microcellular system is much more affected by cell dwell time and channel holding time in each cell. Cell dwell time of a call is characterized by its mobility pattern, i.e., stochastic changes of moving speed and direction. Cell dwell time provides important information for other analyses on traffic performance such as channel holding time, handover rate, and the average number of handovers per call. In the next generation mobile communication system, the cell size is expected to be much smaller than that of current one to accommodate the increase of user demand and to achieve high bandwidth utilization. As the cell size gets small, traffic performance is much more affected by variable mobility of users, especially by that of pedestrians. In previous work, analytical models are based on simple probability models. They provide sufficient accuracy in a simple second-generation cellular system. However, the role of them is becoming invalid in a picocellular environment where there are rapid change of network traffic conditions and highly random mobility of pedestrians. Unlike in previous work, we propose an improved probability model evolved from so-called Random walk model in order to mathematically formulate variable mobility of pedestrians and analyze the traffic performance. With our model, we can figure out variable characteristics of pedestrian mobility with stochastic correlation. The above-mentioned traffic performance measures are analyzed using our model.