• 대한교통학회지
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• 제23권7호
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• pp.35-42
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• 2005

도로 설계속도, 주행속도, 제한속도가 보완적 관계를 가지고 있음에도 불구하고, 이들 세 가지 속도의 상호 작용에 대한 검토가 미흡하였다. 이런 맥락에서 본 연구는 세 가지 속도의 상관성 조사를 위해 지방부의 왕복 4 차로 도로 구간에서 주행속도 자료를 측정하였다. 95 백분위 주행속도를 도로설계기준과 지점별 기하구조 요소로부터 결정되는 곡선부의 추정 설계속도와 상호 비교한 결과, 지점별 추정 설계속도가 100km/h 이하인 조건에서는 주행속도가 추정 설계속도 보다 높게 나타났고, 추정 설계속도가 130km/h 이상의 조건에서는 반대의 현상이 나타났다. 제한속도와 주행속도를 비교한 결과, 제한속도 80km/h 지점에서는 직선부의 85 백분위 주행속도가 $95{\sim}110km/h$ 사이로 나타났고, 제한속도 90km/h 지점에서는 $105{\sim}120km/h$ 사이로 나타났다. 다중 회귀 분석을 이용하여 접근 직선부와 곡선부 중간 지점에서 평균, 85 백분위, 95 백분위 주행속도를 예측하기 위한 모형식 개발을 시도하였다. 분석 결과, 제한속도가 증가할수록 곡선부의 평균 주행속도, 85 백분위 주행속도가 증가하는 것으로, 직선부에서는 제한속도가 증가하고 접근 직선의 연장이 길어질수록 평균, 85 백분위, 95 백분위 주행속도가 증가하는 것으로 나타났다.

• 한국안전학회지
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• 제25권6호
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• pp.186-196
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• 2010

It has been well known that traffic accidents occur under combined functional contributions of drivers, vehicles and road facilities, and that evaluation of safety levels for a specific road section or point is generally much complicated. Additionally, most of traffic accidents occur randomly implicating it is necessary to be evaluated in terms of probability theory. Thus, the evaluation model which reflects various characteristics and probabilistic distributions of traffic accidents has been necessary. The present paper provides a reliability based model with variables of probabilistic operating speeds and design speeds together which have been individually explaining associated characteristics in traffic accidents. Consequently, the model made it possible for speed management and road improvement projects to be evaluated in a common index. Application studies were performed in three cases. Through the studies, couples of facts were identified that the model successfully considered the probabilistic operating speeds and design speeds together and that then, the model evaluated road safety alternatives relatively which are complicatedly characterized and differently located.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1988년도 가을 학술발표회 논문집
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• pp.7-12
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• 1988

This study presents rational methods for probability-based estimates of basic design wind speeds in Korea and develops a risk-bases nation-wide map of design wind speeds. The paper examines the fitting of the Type-I extreme model to maximum yearly non-typhoon wind data from long-term records based on the conventional method and to maximum monthly nod-typhoon wind data from short-term records following Grigorin's approach. The paper also reviews the applicability of the method using short records of about 5 years. The basic design wind speeds for typhoon and non-typhoon wind at a station are made to be obtained from a mixed model which is given as a product of typhoon and non-typhoon extreme wind distributions. A practical method which is based on the fitting of the Type I model to records or typhoon and non-typhoon mixed wind data at a station is also preposed in this study.

• Wind and Structures
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• 제31권2호
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• pp.85-102
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• 2020

Accurate load evaluation is essential in any performance-based design. Design wind speeds and associated wind loads are well defined for synoptic boundary layer winds but not for thunderstorms. The method presented in the current study represents a new approach to obtain design wind speeds associated with thunderstorms and their gust fronts using historical data and Monte Carlo simulations. The method consists of the following steps (i) developing a numerical model for thunderstorm downdrafts (i.e. downbursts) to account for storm translation and outflow dissipation, (ii) utilizing the model to characterize previous events and (iii) extrapolating the limited wind speed data to cover life-span of structures. The numerical model relies on a previously generated CFD wind field, which is validated using six documented thunderstorm events. The model suggests that 10 parameters are required to describe the characteristics of an event. The model is then utilized to analyze wind records obtained at Lubbock Preston Smith International Airport (KLBB) meteorological station to identify the thunderstorm parameters for this location, obtain their probability distributions, and utilized in the Monte Carlo simulation of thunderstorm gust front events for many thousands of years for the purpose of estimating design wind speeds. The analysis suggests a potential underestimation of design wind speeds when neglecting thunderstorm gust fronts, which is common practice in analyzing historical wind records. When compared to the design wind speed for a 700-year MRI in ASCE 7-10 and ASCE 7-16, the estimated wind speeds from the simulation were 10% and 11.5% higher, respectively.

• 전산구조공학
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• 제2권2호
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• pp.62-72
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• 1989

본 연구는 확률에 기초한 한국의 기본 설계풍속 추정을 위한 합리적인 방법을 제시하고 위험도에 기초한 전국의 설계풍속지도를 제안한다. 본 논문에서는 장기기록 지역의 계절풍 연 최대 풍속자료와 단기기록 지역의 계절풍 월 최대 풍속자료의 극치 Type I 분포 모형에 대한 적합성을 검토하였고, 극치 태풍 풍속 분포 추정에서는 Monte-Carlo 시뮬레이션을 이용하여 간접적인 해석방법이 적용되었다. 태풍과 계절풍에 대한 기본 설계풍속은 두개 분포의 적(product)으로 된 혼합모형에서 구한다. 본 연구 결과로부터 제안된 모형과 방법은 현재 한국에서 가용한 단기기록 풍속자료를 이용한 위험도에 기초한 기본설계풍속과 기본 설계풍속지도의 개발에 실용적인 도구로 활용 가능하다고 본다.

• 한국안전학회지
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• 제27권5호
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• pp.158-163
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• 2012

This study is concerned with the estimation of wind speeds for return period in cellularized district of Busan by the recent meteorological data. Recently standard of the wind load in Busan area is determined by using meteorological wind speed data which is observed on Automated Synoptic Observing System(ASOS) only. Applying the existing basic wind speed that is 40m/s to the construction design of Busan area is inefficient. Because the wind speeds of Busan area show different amounts depend on the location of cellularized district. This research analyze the observed data of wind speeds of cellularized district in Busan based on Automate Weather System(AWA). In addition that we compute regional wind speeds for return period by using Gumbel distribution and study and compare with the existing basic wind speeds after evaluating appropriateness by Hazen's plot method.

• 한국도로학회논문집
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• 제18권4호
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• pp.77-82
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• 2016

PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

• 산업경영시스템학회지
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• 제35권1호
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• pp.140-147
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• 2012

Vehicle routing problem is one of the traveling salesman problems with various conditions such as vehicle capacity limits, delivery time windows, as well as time dependent speeds in metropolitan area. In this research hourly vehicle moving speeds information in a typical metropolitan area are analyzed to use the results in the design procedure of VRP heuristic. Quality initial vehicle routing solutions can be obtained with adaption of the analysed results of the time periods with no vehicle speed changes. This strategy makes complicated time dependent vehicle speed simple to solve. Time dependent vehicle speeds are too important to ignore to obtain optimum vehicle routing search for real life logistics systems.

• 한국도로학회논문집
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• 제18권2호
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• pp.103-110
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• 2016

PURPOSES: In this paper, the effectiveness of speed-maintained standardization in road geometry on environmental impact at a downward slope location, based on greenhouse gas (GHG) emission indicators, was studied. Specifically, the aim of this study was to ascertain whether speed-maintained standardization resulted in decreased $CO_2$ emissions as well as noise pollution, due to reduced vehicle speeds. METHODS : In this study, speed-maintained standardization in road geometry was proposed as a means to reduce vehicle speeds, with a view to reducing $CO_2$ emissions and noise pollution. This technique was applied at a downward slope location. The vehicle speeds, $CO_2$ emissions, and noise levels before and after application of speed-maintained standardization were compared. RESULTS: It was found that speed-maintained standardization was effective as a means to reduce speed, as well as $CO_2$ emissions and noise pollution. By applying speed-maintained standardization, it was confirmed that vehicle speeds were reduced consistently. As a result, $CO_2$ emissions and noise levels were decreased by 9% and 11%, respectively. CONCLUSIONS : This study confirmed that speed-maintained standardization in road geometry is effective in reducing vehicle speeds, $CO_2$ emissions, and noise levels. Moreover, there is further scope for the application of this method in the design of roads in urban and rural areas, as well as in the design of highways.

• Wind and Structures
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• 제30권2호
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• pp.141-153
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• 2020

Probabilistic information regarding directional extreme wind speeds is important for the precise estimation of the design wind loads on structures. A joint probability distribution model of directional extreme typhoon wind speeds is established using Monte Carlo simulation and empirical copula function to fully consider the correlations of extreme typhoon wind speeds among the different directions. With this model, a procedure for estimating directional extreme wind speeds for given return periods, which ensures that the overall risk is distributed uniformly by direction, is established. Taking 5 typhoon-prone cities in China as examples, the directional extreme typhoon wind speeds for given return periods estimated by the present method are compared with those estimated by the method proposed by Cook and Miller (1999). Two types of directional factors are obtained based on Cook and Miller (1999) and the UK standard's drafting committee (Standard B, 1997), and the directional risks for the given overall risks are discussed. The influences of the extreme wind speed correlations in the different directions and the simulated typhoon wind speed sample sizes on the estimated extreme wind speeds for a given return period are also discussed.