• 한국통신학회논문지
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• 제42권5호
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• pp.1069-1076
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• 2017

C-ITS(Cooperative-Intelligent Transportation System)는 전방 충돌 경고, 도로 안전 서비스 및 비상 정지와 같은 엄격한 실시간성이 요구되는 서비스들을 제공한다. C-ITS의 핵심 기술인 WAVE(Wireless Access in Vehicular Environments)는 고속 이동 환경을 위해 고안된 기술이지만, 실제 도로 환경에 적용하여 안정적인 통신 서비스를 제공하기 위해서는 실차 환경의 다양한 성능 시험이 요구된다. 실제 도로 환경에서 WAVE 통신 성능은 이동 중인 차량, 도로의 형상 및 지형 등의 주변 환경에 의해 영향을 받으며 특히, 차량이 고속으로 이동하는 경우 차량의 속도에 따라 주행하는 위치와 노변장치와의 접근성 등 주변 환경이 빠르게 변화한다. 이 변화는 통신 성능에 영향을 주는 요소이므로 이를 분석하기 위한 시스템과 방법이 필요하다. 본 논문에서는 고속 주행 환경에서 효과적인 성능 시험 시스템 구성과 시험 방법을 제안하고, 실차 시험을 통해 측정한 데이터를 기반으로 통신 성능을 분석한 결과를 제시한다.

• 한국도로학회논문집
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• 제17권2호
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• pp.79-87
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• 2015

PURPOSES: According to accident statistics for road built in 2004, the ratio of accidents on frozen roads to normal roads is 0.9%, whereas the fatality ratio is 2.7%. The risk of accidents on frozen roads is very high. Measures taken every year to prevent traffic accidents of frozen roads in the winter season are still insufficient. Additionally, measures have been established mainly on rural roads. Therefore, for urban roads, analyses and measures to prevent accidents are lacking. In this study, data on accidents on frozen roads was used to search for the causes behind these accidents and measures to reduce accidents have been recommended. METHODS: In this study, collected data from the TAMS (Traffic Accident Management System), which were collected by the Seoul National Police Agency was used. The data were divided into vehicle, people, and condition of road. The analytical model used here was the Logistic Regression Model, which is frequently used for traffic safety and accident analysis. This study uses the odds ratio analysis to search for variables related to frozen road traffic accidents in each category. A total of 18 out of 47 variables were found to be the causes of accidents. RESULTS: From the results of the comparative analysis of 18 variables, the category of the condition of the road was found to be the most critical. Contrary to expectations, more accidents occurred in clear weather than in other conditions. Accidents on bridges occurred frequently, and its odds ratio was the highest compared with other road types. When BPT is operated, the probability of accidents on frozen roads is lower than in general conditions, and accidents occurred frequently on roads with less than four lanes. CONCLUSIONS : Based on the results of this study, suggestions for reducing the risk of future domestic road accidents in freezing conditions are indicated as follows. First, it is necessary to perform a technical review of the urban road traffic accidents caused by frozen roads. Second, it is necessary to establish criteria for the study of the road environment based on the major causes of road accidents on frozen roads. Third, improvements in urban road environmental factors should be made.

• 전기학회논문지P
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• 제63권3호
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• pp.178-182
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• 2014

This paper investigates the lighting environment of railway system which are mainly used in KTX, Saemaul and Mugunghwa. When lighting used in KTX such as fluorescent lamp and incandescence is being replaced with LED lamp, illumination load of each railroad vehicle has been compared. The comparison result shows that the reduction of power consumption is 43.34% before and after the change. Also it has been performed the economic evaluation.

• 한국대기환경학회지
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• 제12권5호
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• pp.517-521
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• 1996

Surface soils sampled at several sites in Seoul, Korea were analyzed to determine the concentrarions and distributions of PAHs. Results are as follow; 1) The Bap concentration in soils was found to be the highest in the industrial area (128 ng/g) and lowest in the residential area(19 ng/g). 2) The Py concentration in soils was highest in the tunnel area (1,110 ng/g) and the lowest in the Achasan area(18 ng/g). 3) The BghiP concentration in soils was higher in road (538 ng/g) and tunnel (532 ng/g) areas than in others areas. 4) It was shown that the PAHs concentrations in residential areas were affected by combution of fossil fuel, those in industrial, road, tunnel, terminal and commercial areas were affected by vehicle exhaust.

• 한국대기환경학회지
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• 제12권5호
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• pp.523-528
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• 1996

Aerosol Particles were collected in a heaby traffic region in pusan. Samples were collected in two size fractions with a two-stage sampler during the day and the night. Elemental concentrations of these aerosol particles were determined by a PIXE(Proton Induced X-ray Emission) analysis method. The results suggest that the elements originating mainly from natural sources such as Si, Ca, Fe, Cl, and K are dominent in the coarse fraction, but the elements such as S, Pb, Br, and Zn are dominent in the fine fraction. Br/Pb ratio are evaluated in both coarse and fine size fraction, and which are mainly emitted automobile sources. The study further also discussed other Br/Pb ratio related works described elsewhere. Sulfur in the fine fraction was continuously increased during the sampling period without time variation.

• 한국조경학회지
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• 제23권3호
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• pp.1-14
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• 1995

The aspect of visual accessibility to urban green spaces is an important factor because it contributes making pleasant environment by increasing the visual experience of nature in urban environment. But we have tried neither to consider nor to measure it. Since he concept of visual accessibility has not formally defined yet, it was operationally defined in this study. And then the model of measuring visual accessibility was suggested and verified through the case study on neighborhood parks in Seoul. The findings are as follows : 1) The concept of visual accessibility is defined as opportunity and potentiality to observe green spaces. 2) The model of measuring visual accessibility deals with not only adjacent area but also viewshed area. In adjacent area, considering factors are the area of road adjacent to green spaces and the area of exposed green spaces. In viewshed area, considering factors are the area of road located in viewshed area, the area of exposed green spaces, and the weight according to observing distance. 3) The final model of measuring visual accessibility suggested in this study is as follows.

• 로봇학회논문지
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• 제16권2호
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• pp.122-129
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• 2021

For the Simultaneous Localization and Mapping (SLAM) problem, a different path results in different SLAM results. Usually, SLAM follows a trail of input data. Active SLAM, which determines where to sense for the next step, can suggest a better path for a better SLAM result during the data acquisition step. In this paper, we will use reinforcement learning to find where to perceive. By assigning entire target area coverage to a goal and uncertainty as a negative reward, the reinforcement learning network finds an optimal path to minimize trajectory uncertainty and maximize map coverage. However, most active SLAM researches are performed in indoor or aerial environments where robots can move in every direction. In the urban environment, vehicles only can move following road structure and traffic rules. Graph structure can efficiently express road environment, considering crossroads and streets as nodes and edges, respectively. In this paper, we propose a novel method to find optimal SLAM path using graph structure and reinforcement learning technique.

• 한국대기환경학회지
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• 제5권1호
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• pp.79-87
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• 1989

In order to reduce the smoke emission from the in-service city bus, this study was evaluated the particulate reduction efficiency and regeneration ability of the catalitic trap oxidizer (CTO) on the city bus (D0846HM engine) equipped with it. Before the on-road CTO test, the laboratory test of CTO on engine test-bench was performed. Reduction efficiencies of smokes and particulates were 54 and 45%, and those of gaseous pollutants such as carbon monoxide (CO) and hydrocarbons (HC) were 90 and 60%. In order to evaluate the regeneration ability of the CTO by the catalytic oxidation of trapped particulate, field test was performed on the in-service road. The regeneration temperature was 350$^\circ$ which was same with the exhaust temperature of city bus.

• 한국농공학회논문집
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• 제57권4호
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• pp.39-49
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• 2015

Since most medical facilities and medical personnel are concentrated in urban areas in South Korea, an imbalance of access to medical facilities causes a gap in medical resource availability between urban and rural areas. Accessibility to medical facilities is a means of assessment that evaluates a measure of inequality in utilization of medical resources. The evaluation of accessibility uses Euclidean distance, in general; however, this method has its limits in that Euclidean distance cannot reflect actual distance. This study aims to estimate real road distance from village halls to medical facilities in rural areas using Open Application Programming Interface (Open API) of an internet portal site. Using real road distance, we evaluated medical accessibility and compared it with Euclidean distance. The accessibility to primary medical institutions was valued relatively well, but secondary and tertiary medical institutions were vulnerable in Pyeonchang-gun. Comparing Euclidean distance with real road distance from village halls to medical facilities, real road distance appeared to be approximately 1.4 times that of Euclidean distance. This calculation is similar to the circuity factor of Gangwon-do in Korea that estimated to fix the limits of Euclidean distance and assumed real road distance.

• 한국지능시스템학회논문지
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• 제18권5호
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• pp.599-604
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• 2008

최근 외부 개입 없이 스스로 주변 환경을 파악하고 목적지까지의 이동경로를 생성하여 자율 주행하는 지능형 시스템에 관한 연구가 활발히 진행되고 있다. 이러한 자율 주행 시스템은 기본적으로 운행 중에 사고가 발생하지 않고 안전하게 목표점까지 이동해야 한다. 본 논문에서는 레이저 변위 센서를 이용하여 노면의 왜곡(훼손된 노면, 비포장 도로, 장애물 등)을 검출하고, 영상 이진화 기법을 적용하여 위험 요소를 검출, 판단하여 주행 시스템의 안정적 운항이 가능한 경로를 생성하는 기법을 제안한다. 제안 기법의 타당성은 임의로 제작된 국부영역의 지도 데이터에 기반한 모의실험을 통하여 보인다.