• The Journal of the Korea Contents Association
• /
• v.15 no.11
• /
• pp.582-590
• /
• 2015

Road type classification and K-factors are important role when design of number of lane. In this study not only classifies road type and estimating of K-factor but also economic evaluation tries for feasibility verification. Road type analysis results, time of day traffic volume variation, weekend-factor and vacation-factor are large in recreation roads. Weekday traffic volume and weekend traffic volume are similar patterns in provincial roads. AADT is high and time of day traffic volume variation is small in urban roads. In this study compares with economic analysis that designing of number of lane between KHCM's K-factor and this study K-factor. Economic analysis results, designed roads by this study's K-factor reduce cost about 4,708 hundred million won. So this study's K-factor is economical on provincial 4 lane roads.

• Journal of Digital Contents Society
• /
• v.10 no.2
• /
• pp.357-365
• /
• 2009

To effectively exploit the underlying network bandwidth while maximizing user perceivable QoS, mandatory to make proper estimation on packet loss and queuing delay of the underling network. This issue is further emphasized in wireless network environment where network bandwidth is scarce resource. In this work, we focus our effort on developing performance model for wireless network. We collect packet trace from actually wireless network environment. We find that packet count process and bandwidth process in wireless environment exhibits long range property. We extract key performance parameters of the underlying network traffic. We develop an analytical model for buffer overflow probability and waiting time. We obtain the tail probability of the queueing system using Fractional Brown Motion (FBM). We represent average queuing delay from queue length model. Through our study based upon empirical data, it is found that our performance model well represent the physical characteristics of the IEEE 802.11b network traffic.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.9
• /
• pp.4125-4132
• /
• 2011

The research of image quality estimation standard and the image quality change according to the network traffic load increase at IPTV multicasting service is necessary because the concern of IPTV(Internet Protocol TV) service become active recently. In the research, for finding out the threshold value of network performance elements giving the effect to the image quality according to the network traffic load, we developed S/W to operate the test bed network and make the test scenario through test bed network test and then we expand the test environment scope to the college network and try to measure the image quality change of IPTV multicasting service according to the network traffic load increase at the college network similar to the real IPTV service environment.

• Structural Engineering and Mechanics
• /
• v.20 no.1
• /
• pp.85-110
• /
• 2005

This paper aims at formulating various statistical models for the study of a ten year Weigh-in-Motion (WIM) data collected from various WIM stations in Hong Kong. In order to study the bridge live load model it is important to determine the mathematical distributions of different load affecting parameters such as gross vehicle weights, axle weights, axle spacings, average daily number of trucks etc. Each of the above parameters is analyzed by various stochastic processes in order to obtain the mathematical distributions and the Maximum Likelihood Estimation (MLE) method is adopted to calculate the statistical parameters, expected values and standard deviations from the given samples of data. The Kolmogorov-Smirnov (K-S) method of approach is used to check the suitability of the statistical model selected for the particular parameter and the Monte Carlo method is used to simulate the distributions of maximum value stochastic processes of a series of given stochastic processes. Using the statistical analysis approach the maximum value of gross vehicle weight and axle weight in bridge design life has been determined and the distribution functions of these parameters are obtained under both free-flowing traffic and dense traffic status. The maximum value of bending moments and shears for wide range of simple spans are obtained by extrapolation. It has been observed that the obtained maximum values of the gross vehicle weight and axle weight from this study are very close to their legal limitations of Hong Kong which are 42 tonnes for gross weight and 10 tonnes for axle weight.

• Communications for Statistical Applications and Methods
• /
• v.30 no.1
• /
• pp.95-107
• /
• 2023

Purpose: The statistical analysis of point processes on linear networks is a recent area of research that studies processes of events happening randomly in space (or space-time) but with locations limited to reside on a linear network. For example, traffic accidents happen at random places that are limited to lying on a network of streets. This paper applies techniques developed for point processes on linear networks and the tools available in the R-package spatstat to estimate the intensity of traffic accidents in Leon County, Florida. Methods: The intensity of accidents on the linear network of streets is estimated using log-linear Poisson models which incorporate cubic basis spline (B-spline) terms which are functions of the x and y coordinates. The splines used equally-spaced knots. Ten different models are fit to the data using a variety of covariates. The models are compared with each other using an analysis of deviance for nested models. Results: We found all covariates contributed significantly to the model. AIC and BIC were used to select 9 as the number of knots. Additionally, covariates have different effects such as increasing the speed limit would decrease traffic accident intensity by 0.9794 but increasing the number of lanes would result in an increase in the intensity of traffic accidents by 1.086. Conclusion: Our analysis shows that if other conditions are held fixed, the number of accidents actually decreases on roads with higher speed limits. The software we currently use allows our models to contain only spatial covariates and does not permit the use of temporal or space-time covariates. We would like to extend our models to include such covariates which would allow us to include weather conditions or the presence of special events (football games or concerts) as covariates.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.12
• /
• pp.106-115
• /
• 2003

Diverse multimedia services will be deployed at hand on 3G-and-beyond multi-service CDMA systems in order to satisfy different quality of service (QoS) according to traffic types. In order to use appropriate resources efficiently the call admission control (CAC) as a major resource control mechanism needs to be used to take care of efficient utilization of limited resources. In this paper, we propose a QoS-aware CAC (QCAC) that is enabled to provide service fairness and service differentiation in accordance with priority order and that applies the different thresholds in received power considering different QoS requirements such as different bit error rates (BER) when adopting total received power as the ceil load estimation. The proposed QCAC calculates the different thresholds of the different traffic types based on different required BER applies it for admission policy, and can get service fairness and differentiation in terms of call dropping probability as a main performance metric. The QCAC is aware of the QoS requirement per traffic type and allows admission discrimination according to traffic types in order to minimize the probability of QoS violation. Also the CAC needs to consider the resource allocation schemes such as complete sharing (CS), complete partitioning (CP), and priority sharing(PS) in order to provide fairness and service differentiation among traffic types. Among them, PS is closely related with the proposed QCAC having differently calculated threshold per each traffic type according to traffic priority orders.

• Journal of the Korean Society of Safety
• /
• v.32 no.2
• /
• pp.132-146
• /
• 2017

Appropriate speed limits at a reasonable level in urban roads are highly important factors for efficient and safe movement. Thus, it is greatly necessary to develop the objective models or methodology based on engineering study considering factors such as traffic accident rates, roadside development levels, and roadway geometry characteristics etc. The purpose of this study is to develop the estimate model of appropriate speed limits at each road sections in urban roads using traffic information big data and field specific data and to review the effects of accident decrease. In this study, the estimate method of appropriate speed limits in directional two or more lanes of urban roads is reflecting features of actual variables in a form of adjustment factor on the basis of the maximum statutory speed limits. As a result of investigating and testing influential variables, the main variables to affect the operating speed are the function of road, the existence of median, the width of lane, the number of traffic entrance/exit path and the number of traffic signal or nonsignal at intersection and crosswalk. As a result of testing this model, when the differences are bigger between the real operating speed and the recommended speed limits using model developed in this study, the accident rate generally turns out to be higher. In case of using the model proposed in this study, it means accident rate can be lower. When the result of this study is applied, the speed limits of directional two or more lane roads in Seoul appears about 11km/h lower than the current speed limits. The decrease of average operating speed caused by the decrease of speed limits is 2.8km/h, and the decrease effect of whole accidents according to the decrease of speed is 18% at research road. In case that accident severity is considered, the accident decrease effects are expected to 17~24% in fatalities, 11~17% in seriously injured road user, 6~9% in slightly injured road user, 5~6% in property damage only accidents.

• Journal of Korean Society of Transportation
• /
• v.23 no.3 s.81
• /
• pp.125-136
• /
• 2005

The current traffic accident reduction procedure in economic feasibility study does not consider the characteristics of road and V/C ratio. For solving this problem, this paper suggests methods to be able to evaluate safety of each road in construction and improvement through developing accident Prediction model in reflecting V/C ratio Per road types and traffic characters. In this paper as primary process, model is made by tke object of urban roads. Most of all, factor effecting on accident relying on road types is selected. At this point, selecting criteria chooses data obtained from road planning procedure, traffic volume, existence or non-existence of median barrier, and the number of crossing point, of connecting road. and of traffic signals. As a result of analyzing between each factor and accident. all appear to have relatives at a significant level of statistics. In this research, models are classified as 4-categorized classes according to roads and V/C ratio and each of models draws accident predicting model through Poisson regression along with verifying real situation data. The results of verifying models come out relatively satisfactory estimation against real traffic data. In this paper, traffic accident prediction is possible caused by road's physical characters by developing accident predicting model per road types resulted in V/C ratio and this result is inferred to be used on predicting accident cost when road construction and improvement are performed. Because data using this paper are limited in only province of Jeollabuk-Do, this paper has a limitation of revealing standards of all regions (nation).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.5
• /
• pp.837-844
• /
• 2017

Generally, V/C ratio in uninterrupted traffic flow and average travel speed in interrupted traffic flow are utilized as measure of effect for assessing operational situation of roads. The set of road conditions and traffic conditions are considered to be major variables for assessing operational situation in the traffic flow. However, weather conditions such as rainfall also affect the operational situation of roads. The studies reflected by the rainy situation are conducted in the uninterrupted flow, but the related studies are insufficient in the interrupted flow. In this study, the modification factors during rainfall in the interrupted flow were suggested, and the factors could be used when calculating the average travel speed during rainfall in the interrupted flow. By utilizing the data that were investigated in the same road and traffic conditions and the different weather conditions (rainy day or clear day), the modification factors were founded on regression analysis of the travel speed during rainfall as a dependent variable. Modification factors was suggested in dividing peak time, non-peak time, and whole period. Based on this study, the modification factors can be used to complementing the average travel speed model for assessing the operational situation of urban streets during rainfall.

• Journal of Korean Society of Transportation
• /
• v.23 no.2
• /
• pp.95-106
• /
• 2005

Road accidents are considered as the result of a complex interplay between road, vehicle, environments, and human factors. Little study, however, has been carried out on the attributes of human factor compared to the road geometric conditions and traffic conditions. The previous researches focused on mainly both traffic and geometric conditions on specific location. Therefore, it's hard to explain phenomenon of the high traffic accident rates where road and traffic conditions are good. Because of these reasons, accident analysis has contributed on geometric improvement and has not contributed on traffic management such as selection of attention section, driver napping alert, etc. The freeway incident management is also associated with reliable prediction of incident occurrences on freeway sections. This paper presents a method for estimating the effect of trip length on freeway accident rate. A PAR (Potential Accident Ratio), the new concept of accident analysis, considering TLFDs (Trip Length Frequency Distributions) is suggested in this paper. This approach can help to strengthen freeway management and to reduce the likelihood of accidents.