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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society of Transportation
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Korean Society of Transportation
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Volume & Issues
Volume 18, Issue 6 - Dec 2000
Volume 18, Issue 5 - Oct 2000
Volume 18, Issue 4 - Aug 2000
Volume 18, Issue 3 - Jun 2000
Volume 18, Issue 2 - Apr 2000
Volume 18, Issue 1 - Feb 2000
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A Study on Improvement of Run-Time in KS-SIGNAL, Traffic Signal Optimization Model for Coordinated Arterials
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 7~18
KS-SIGNAL, a traffic signal optimization model for coordinated arterials, is an optimization model using the mixed integer linear Programming that minimizes total delay on arterials by optimizing left-turn Phase sequences. However, the Previous version of KS-SIGNAL had a difficulty in reducing computation speed because the related variables and constraints multiply rapidly in accordance with the increase of intersections. This study is designed to propose a new model, improving optimizing computation speed in KS-SIGMAl, and evaluate it. This Paper Puts forth three kinds of methodological approaches as to achieve the above goals. At the first step to reduce run-time in the proposed model objective function and a few constraints are Partially modified, which replaces variable in related to queue clearance time with constant, by using thru-movements at upstream intersection and the length of red time at downstream intersection. The result shows that the run-time can be reduced up to 70% at this step. The second step to load the library in LINDO for Windows, in order to solve mixed integer linear programming. The result suggests that run-time can be reduced obviously up to 99% of the first step result. The third step is to add constraints in related to left-turn Phase sequences. The proposed methodological approach, not optimizing all kinds of left-turn sequences, is more reasonable than that of previous model , only in the view of reducing run-tim. In conclusion, run-time could be reduced up to 30% compared with the second results. This Proposed model was tested by several optimization scenarios. The results in this study reveals that signal timing plan in KS-SIGNAL is closer to PASSER-II (bandwidth maximizing model) rather than to TRANSYT-7F(delay minimizing model).
Estimation of Transfer Related Values of Seoul Subway Users Using Stated Preference and Revealed Preference Analyses
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 19~30
The purpose of the Paper is to estimate values of transfer related variables on route choices of subway users in Seoul. Four attributes were estimated affecting route choices, i.e. in-vehicle time, transfer time, number of transfers and existence of escalators. Stated preference and revealed preference techniques were used to estimate these values. The values of transfer related variables can be shown by in-vehicle time equivalents. One minute of transfer is 1.5∼2 times one minute of in vehicle times one time of transfer is 10∼15 times, and the existence of escalator is 2∼8 times. Women generally show stronger impedance than men and the elder does than the younger. Working, commuting and educational trips show stronger impedance than others too.
Effects of a Hand-Free Cellular Phone Use on Driver's Mental Workload and Performance in an Urban Area
Cha, Doo-Wonn ; Tsuyoshi, Katayama ; Nobuyuki, Uchida ; Park, Peom ;
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 31~39
Cellular Phone use while driving is one of the critical causes of traffic accident by falling the driver into the improper lookout and inattention situations by disturbing the driving behaviors and by increasing the driver's mental workloads. These days, therefore, governments in many countries are trying to Prohibit the cellular Phone use while driving by the law focused on the hand-held type of cellular phone. This Paper investigated the impacts on the hands-free cellular Phone use while driving to the drivers Performance among normal and two different level of secondary task driving conditions in the urban of Japan. As the results, quantitative differences of drivers eye movement, subjective mental workload, steering wheel angle entropy, and cognitive Performance of secondary tasks were compared between straight and curve (right turn) section for each driving condition.
Right Turn Blocking Time By Pedestrian Volume at Signalized Intersection Crosswalks
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 41~50
At signalized intersections, most of the lane that is on the right end, are used as a shared lane for the right turns. On KHCM, the
becomes the important factor of calculating the on deciding the volume of the shared lanes. But the internal research is quite low, so it is assumed that this research is necessary. The purpose of this research is to calculate the time proportion for the right turn vehicles which can not make a right turn on the intersections' pedestrian crossing-time Proportion for the int cross over with the Pedestrians. According to the numbers of the Pedestrians on intersections, the Percentage for the right turn vehicles passage is given. From this, the impossible time Proportion for the right turning vehicles while on intersection Pedestrian signal time was calculated. The research and analysis was Proceeded by the method of analysing the number of Pedestrians on cross-over directions of the crosswalk on straight signal time and Photographing the vehicles for whether or not they are Passing or not. According to the results, time Proportion that cannot turn to the right is estimated to be from 0.78 to 0.94 while Pedestrian volume changes from 500peds/hr to 1,500peds/hr The Proportion is larger than that of H7CM in which 0.3 to 0.9 is Proposed for the same Pedestrian volume. Capacity is more affected by the Percentage of right turn vehicles than by the Pedestrian volume on crosswalk
Reevaluation of Lane Width Widenings on Horizontal Curve Sections
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 51~62
The objective of this study was to reevaluate current Korean design values for lane width widenings on horizontal currie sections and to develop a new method for derivation of design values based on low-speed offtracking. For this purpose, earlier research were reviewed and necessary equations were derived. Also, the method for derivation of widening values of Korea was compared with that for other countries. The result showed that present Korean method could not consider the variation of lane widths and design speeds of roads. In this Paper, to solve such problems, the new concept of widening was developed. That is the current concept of widening which concerns only the dimension of vehicles and radius of curves was replaced by a new concept that lane width widenings on horizontal curve sections is the difference between the width required on curries and tangents. The width required on a curve consists of the swept Path of a vehicle, lateral clearance, and additional allowance. The width of a tangent is calculated by multiplying lane width by the number of lanes The result of applying new concept shows that the values derived from new concept are higher than current design values for curries have same radius. This study was based only on low-speed offtracking. Therefor, it is recommended that further studies which consider the superelevation and high-speed effect on offtracking be made to derive more accurate widening values .
Promoting Policy of the Green modes as a Sustainable Transportation System in Korea (Green modes promoting movement in Korea : backgrounds, processing, prospect)
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 63~72
In the past 70 years, various policies for Promotion of green modes (PPGMS) have introduced in Korea as a sustainable transportation system. However, so many problems are expected that PPGMS are to become fixed as successful transportation Policies. Thus, this study argues that the PPGMS must be executed in its systematic short-, mid- and long-term strategies for it to be an effective catalyst toward bringing about sustainable cities for the future.
Training Sample of Artificial Neural Networks for Predicting Signalized Intersection Queue Length
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 75~85
The Purpose of this study is to analyze wether the composition of training sample have a relation with the Predictive ability and the learning results of ANNs(Artificial Neural Networks) fur predicting one cycle ahead of the queue length(veh.) in a signalized intersection. In this study, ANNs\` training sample is classified into the assumption of two cases. The first is to utilize time-series(Per cycle) data of queue length which would be detected by one detector (loop or video) The second is to use time-space correlated data(such as: a upstream feed-in flow, a link travel time, a approach maximum stationary queue length, a departure volume) which would be detected by a integrative vehicle detection systems (loop detector, video detector, RFIDs) which would be installed between the upstream node(intersection) and downstream node. The major findings from this paper is In Daechi Intersection(GangNamGu, Seoul), in the case of ANNs\` training sample constructed by time-space correlated data between the upstream node(intersection) and downstream node, the pattern recognition ability of an interrupted traffic flow is better.
Application of Fuzzy Group Decision Theory on Deciding Priorities of Transport Investments
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 87~94
This Paper suggests an applicable method when the priority order of transport investments is decided. This method may be considered as a supplementary method for existing investment appraisal methods. When the Priority orders of transport investments such as highways and railways are evaluated, the unique characteristics of the investments should be evaluated, too. The characteristics include comfort, attractiveness, relation to existing and future similar and other transport systems, etc. They have hardly been evaluated objectively or mathematically. The method suggested in this paper is to reflect the characteristics in the evaluation or appraisal Process with experiences and judgements of related experts. The basic theory of the Proposed method is the group decision theory with application of fuzzy relation. The method can draw the priority order of a group from individual priority orders. Also, the method can estimate the level of satisfaction of the group for the result of Priority order. This output may increase the creditability of decision makers who wish to produce it more objectively and Professionally
Trip Generation Model Using Backpropagation Neural Networks in Comparison with linear/nonlinear Regression Analysis
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 95~105
The Purpose of this study is to present a new Trip Generation Model using Backpropagation Neural Networks. For this purpose, it is compared the performance between existing linear/nonlinear Regression models and a new TriP Generation model using Neural Networks. The study was performed according to the below. First, it is analyzed the limits of conventional Regression models, next Proved the superiority of Neural Networks model in theoretical and empirical aspects, and lastly Presented a new approach of Trip Generation methodology. The results show that Backpropagation Neural Networks model is predominant in estimation and Prediction comparable to Regression analysis. Such results mean the possibility of Neural Networks\` application in Trip Generation modeling. Specially under the circumstances of the chancing transportation situations and unstable transportation on vironments, its application in transportation fields will be extended.
Automobile Collision Reconstruction Using Post-Impact Velocities and Crush Profile
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 107~115
We suggest a method which solves the planar, two vehicle collision reconstruction problem. The method based on the Principle of impulse and momentum determines the pre-impact velocity components from Post-impact velocity components, vehicle Physical data and collision geometry. A novel feature is that although the impact coefficients such as the restitution coefficient and the impulse ratio are unknown, the method can estimate automatically the coefficients and calculate the pre-impact velocity components. This reverse calculation is important for vehicle accident reconstruction, since the pre-impact velocities are unknown and Post-impact Phase is the starting Point in a usual collision analysis. However. an inverse solution is not always Possible with the analytical rigid-body impact model. Mathematically, one does not exist under the common velocity condition. On the other hand, our method has a capability of reverse calculation under the condition if the absorbed energy during the collision process can be estimated using the crush profile. To validate the developed collision reconstruction a1gorithm, we use car-to-car collision test results. The analysis and experimental results agree well in the impact coefficients and the Pre-impact velocity components.
Development and application of GLS OD matrix estimation with genetic algorithm for Seoul inner-ringroad
Journal of Korean Society of Transportation, volume 18, issue 4, 2000, Pages 117~126
Conventional methods for collecting origin-destination trips have been mainly relied on the surveys of home or roadside interview. However, the methods tend to be costly, labor intensive and time disruptive to the trip makers, thus the methods are not considered suitable for Planning applications such as routing guidance, arterial management and information Provision, as the parts of deployments in Intelligent Transport Systems Motivated by the problems, more economic ways to estimate origin-destination trip tables have been studied since the late 1970s. Some of them, which have been estimating O-D table from link traffic counts are generally Entropy maximizing, Maximum likelihood, Generalized least squares(GLS), and Bayesian inference estimation etc. In the Paper, with user equilibrium constraint we formulate GLS problem for estimating O-D trips and develop a solution a1gorithm by using Genetic Algorithm, which has been known as a g1oba1 searching technique. For the purpose of evaluating the method, we apply it to Seoul inner ringroad and compare it with gradient method proposed by Spiess(1990). From the resu1ts we fond that the method developed in the Paper is superior to other.