• International Journal of Highway Engineering
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• v.4 no.1 s.11
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• pp.123-134
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• 2002

Special pavement test sections were selected to develop a distress prediction model on asphalt pavement of National Highway. Experimental design was conducted for the selection of LTPP sections on in-service pavement(new and overlaid pavement) using several variables affecting pavement performance. Preliminary sections that satisfied the design template were chosen from the national highway database, and final selection was fixed through field inspection. The number of monitoring section is 95 including 47 overlaid pavement. A pavement distress data such as crack and rutting were collected for two years. An interim pavement performance analysis was peformed to show feasibility of performance monitoring program. Data related pavement such as traffic, weather, material characteristic and crack etc. should be collected for next project years and distress prediction model will be developed through the statistical analysis.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.201-213
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• 2018

In recent years, the number of traffic accidents caused by car accidents has been decreasing steadily due to traffic accident prevention activities in Korea. However, the number of accidents in Seoul is higher than that of other regions. Various studies have been conducted to prevent traffic accidents, which are human disasters. In particular, previous studies have performed the spatial analysis of traffic accidents by counting the number of traffic accidents by administrative districts or by estimating the density through kernel density method in order to identify the traffic accident cluster areas. However, since traffic accidents take place along the road, it would be more meaningful to investigate them concentrated on the road network. In this study, traffic accidents were assigned to the nearest road network in two ways and analyzed by hotspot analysis using Getis-Ord Gi* statistics. One of them was investigated with a fixed road link of 10m unit, and the other by computing the average traffic accidents per unit length per road section. As a result by the first method, it was possible to identify the specific road sections where traffic accidents are concentrated. On the other hand, the results by the second method showed that the traffic accident concentrated areas are extensible depending on the characteristic of the road links. The methods proposed here provide different approaches for visualizing the traffic accidents and thus, make it possible to identify those sections clearly that need improvement as for the traffic environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.423-423
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• 2011

현재 우리나라의 치수대책이나 복구대책은 그 해의 피해액만을 기준으로 이루어지고 있다. 그러나 강우의 특성과 지자체별 홍수피해액의 상관성을 분석한다면 지금의 기준보다 합리적인 치수 대책이나 복구대책을 마련할 수 있다. 본 연구에서는 강우의 특성에 따른 지자체별 홍수피해액을 분석하고자 시 군 구 별로 16년(1994-2009)간의 강우자료(시간최대, 일최대, 누적강우)와 피해액을 비교 평가하였다. 이를 통해 가장 큰 누적피해액을 유발하는 강우사상은 발생횟수나 사상의 크기가 가장 큰 값이 아님을 알 수 있었다. 시간최대강우량의 경우 0-25mm 구간의 발생횟수는 50.72%를 차지했지만 총피해액은 29.08%로 나타났으며, 25-50mm 구간에서의 발생횟수는 37.87%에 불과하나 전체 피해액에서는 42.21%로 가장 크게 나타났다. 일최대강우의 경우에는 0-100mm 의 구간의 발생횟수는 47.59%를 차지했지만 총피해액은 14.73%로 나타났으며, 100-200mm 의구간에서의 발생횟수는 40.64%에 불과하나 피해액은 43.21%로 가장 크게 나타났다. 누적강우의 경우는 0-200mm 구간의 발생횟수는 53.2%, 총피해액은 34.79%를 차지했지만 평균피해액은 800-1000mm 구간이 가장 크게 나타났다. 지자체별로 피해가 주로 발생하는 구간을 이용하여 치수계획이나 복구방안의 기준을 정한다면 현재보다 보다 합리적이고 효과적인 대책을 수립하는데 큰 도움이 될 것으로 판단된다.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.177-185
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• 2011

In order to reduce traffic accidents at long road sections involving high risks of traffic accidents, including tunnels, bridges or curves, the National Police Agency have decided a tentative installation and operation of an automated point-to-point speed enforcement system based on cameras at January, 2007. The first system was established at the direction to Kangreung of Dunnae Tunnel at December, 2007. Currently, the automated point-to-point speed enforcement system operates at 11 sections including eight sections on expressways and three sections on national highways. However, there have been few researches on the effects of the system upon the reduction of traffic accidents in a scientific way. To this end, this research effort was initiated to evaluate the effect of the automated point-to-point speed enforcement system on traffic safety by comparing the number of traffic accidents before and after the installation of the system using a comparison-group(C-G) method. Three-year-long traffic accident data for the expressways were collected in order to evaluate the system. As a result, the installation of the system was found to reduce traffic accidents by 49.97% in average.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.57-66
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• 2007

Weaving is defined as the crossing of two or more traffic streams traveling in the same general direction along a significant length of highway without the aid of traffic control devices. Compared with other freeway sections, perturbation is easy to happen at weaving section. Because there are a lot of lane-changing maneuvers at the weaving section, traffic is subject to turbulence in excess of that normally presents on freeway basic section. This turbulence causes operational problems and its impact must be considered. The purpose of this paper is to perform a basic study on flow characteristics by lane, which can be achieved through analyzing breakdown phenomenon in the microscopic approach. The study made use of data derived from the aerial photography for the microscopic analysis. This research produced the 30-second interval data such as flows, speeds, and densities for the macroscopic analysis and derived the vehicular data to draw time-space diagram for the microscopic analysis. The paper analyzed the traffic characteristics using flows, speeds and densities variation and investigated the conditions of breakdown occurrence with the time-space diagrams. The breakdown phenomenon was identified at weaving section and the propagation from free flow to synchronized flow was observed in this study. In the future, the findings help develop the traffic operational algorithm to manage the traffic congestion under ubiquitous circumstance since the conditions of breakdown Phenomenon can be understood more.

• Journal of Korean Society of Transportation
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• v.24 no.2 s.88
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• pp.19-30
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• 2006

This study deals with the optimized detector location considering the traffic characteristics in National Highway. Although there ave many construction works for ITS in National Highway, there is not specific criteria for detector location which can effect the accuracy of traffic information. This study. therefore. aims to Provide the optimized detector location criteria which can represent the traffic characteristics of National Highway. It collects traffic factors of study area by GPS Probe-car and defector, and Presents the optimized detector location by the correlation analysis between spot-speed and link-travel-time. The main results of this study are as followings ; First, the correlation between the spot-speed and link-travel-time Presents the opposite bell shape of the graph (U-type owe) which is increased it?on the upstream then, declined through some unspecified Point of the link. Second, the optimized detector location usually distributes around midstream of link, even though it does not have a consistency. Third, therefore, the optimized detector location generally should be located between $55{\sim}60%$ of total link length. Forth. high level of vertical slope is one of the most important factors of detector location, so it should be excluded for determination of optimized detector location. Finally, expecting that the results of this study would improve the accuracy of travel time estimation and forecasting.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.7
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• pp.31-40
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• 2004

In this paper, we analyze mathematically the performance of the gated service scheduling in the Interleaved Polling with Adaptive Cycle Time(IPACT) was proposed to control upstream traffic for Gigabit Ethernet-PONs. In the analysis, we model EPON MAC protocol as a polling system and use mean value analysis. We divide arrival rate λ into three regions and analyze each region accordingly In the first region in which λ value is very small, there are very few ONUs' data to be transmitted. In the second region in which λ has reasonably large value, ONUs have enough data for continuous transmission. In the third region, ONUs' buffers are always saturated with data since λ value is very large. We obtain average packet delay, average Queue size, average cycle time of the gated service. We compare analysis results with simulation to verify the accuracy of the mathematical analysis. Simulation requires much time and effort to evaluate the performance of EPONs. On the other hand, mathematical analysis can be widely used in the design of EPON systems because system designers can obtain various performance results rapidly. We can design appropriate EPON systems for varioustraffic property by adjusting control parameters.

• Annual Conference on Human and Language Technology
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• 2002.10e
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• pp.163-168
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• 2002

오늘날 자연어 구문 분석 기술은 만족할 만한 수준에 도달하지 못하고 있고 한국어 구문분석 기술 역시 만족할만한 수준과는 거리가 멀다. 특히 문장의 길이가 긴 문장의 경우 구문분석기가 너무 많은 계산 량으로 인해 제대로 동작하지 못하는 경우가 빈번히 발생하고, 비록 구문구조 결과를 내더라도 정확도가 낮은 경우가 많다. 그 이유는 문장의 길이가 길어질수록 중의성이 매우 증가하여 많은 수의 구문분석 결과가 가능하기 때문이다. 이 중에서 정확한 구문구조를 선택하는 문제는 매우 어려워서 기존의 긴 전체 문장에 대한 구문구조를 한번에 계산하려는 시도는 앞으로도 계속 좋은 결과를 기대하기 어렵다. 따라서 우리는 문장의 길이에 상관없이 항상 안정적으로 결과를 내며, 구문분석에 소요되는 시간이 비교적 짧고, 정확도 역시 높은 구문분석기를 개발하고자 한다. 이를 위하여 전체 문장을 여러 개의 구간으로 분할하여 각 구간을 독립적으로 구문 분석한다. 그 다음 각 구간의 결과를 통합하여 전체 문장에 대한 결과를 생성하는 기법을 택하였다.

• Journal of Korea Multimedia Society
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• v.16 no.3
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• pp.366-374
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• 2013

One of the most important problems in syntactic analysis is syntactic ambiguities. This paper proposes a parsing system and this system can reduce syntactic ambiguities by using segmentation method and argument information method. The proposed system uses morphemes for the input of syntax analysis system, and syntactic analysis system generates all possible parse trees from the given morphemes. Therefore, this system generates many syntactic ambiguity problems. We use three methods to solve these problems. First is disambiguation method in morphological analysis, second is segmentation method in syntactic analysis processing, and the last method is using argument information. Using these three methods, we can reduce many ambiguities in Korean syntactic analysis. In our experiment, our approach decreases about 53% of syntactic ambiguities.

• Informatization Policy
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• v.24 no.2
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• pp.20-42
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• 2017

In this paper, we focus on classification of security threats and definitions of security requirements for Internet banking service. Threats are classified based on the past and potential incidents, based upon which we will be able to propose security requirements. In order to identify security threats, the structure of the Internet banking service is classified into three sections - the financial institutions, the network, and the user-terminal - and we defined arising threats for each section. We focused the analysis especially on the user-terminal section, which is relatively vulnerable, causing difficulties in securing stability of the service as a whole. The analyzed security threats are expected to serve the foundation for safe configuration of various Internet banking services.