• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.141-156
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• 2010

In this paper, understanding there is a limitation with a comprehensive and network approach for the evaluation of existing vehicle and pedestrian environments, the authors focus on developing an integrated approach to assessing these environments. The network evaluation here means the assessment at a three-dimensional level that includes evaluation methods of lines/axes in a spatial concept as well as integration of evaluation indicators being used for vehicles and the walking environment. Grey System Theory (GST) was applied based on the theoretical background for network and comprehensive integrated evaluation, and the evaluation of the vehicle and pedestrian environment was performed by assigning target areas to walking preference zones. As a result of the comprehensive evaluation and analysis by GST, even if the service level is the same as the operating indicators (Highway Capacity Manual) of the vehicle and pedestrian environment, or relatively better, it was identified that the total score could be varied over Grey Category because the observed data are calculated after considering the weights between evaluation indicators by the range of Grey Category on the comprehensive evaluation. Considering comprehensively these points, although the indicators on the operation of roads are relatively good, in the event that the indicators on the safety of roads are bad, it was known that the scores over Grey Category also could be changed. The result is that this evaluation method can be used to evaluate the network concept per lane (per axis) as well as to diagnose the current state by type of urban street in the future.

• Geomechanics and Engineering
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• v.8 no.5
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• pp.631-647
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• 2015

Engineers may encounter unpredictable cavities, sinkholes and karst conduits while tunneling in karst area, and water inrush disaster frequently occurs and endanger the construction safety, resulting in huge casualties and economic loss. Therefore, an optimal classification method based on grey system theory (GST) is established and applied to accurately predict the occurrence probability of water inrush. Considering the weights of evaluation indices, an improved formula is applied to calculate the grey relational grade. Two evaluation indices systems are proposed for risk assessment of water inrush in design stage and construction stage, respectively, and the evaluation indices are quantitatively graded according to four risk grades. To verify the accuracy and feasibility of optimal classification method, comparisons of the evaluation results derived from the aforementioned method and attribute synthetic evaluation system are made. Furthermore, evaluation of engineering practice is carried through with the Xiakou Tunnel as a case study, and the evaluation result is generally in good agreement with the field-observed result. This risk assessment methodology provides a powerful tool with which engineers can systematically evaluate the risk of water inrush in karst tunnels.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.75-84
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• 2012

PURPOSES : This paper aims to improve the evaluation method of the Level of Service(LOS) for urban streets presented by the current Korean Highway Capacity Manual(KHCM) and suggest its utilization plan as a part of the methods to evaluate the sustainability of a transportation policy. METHODS : This paper carried out a research in 3 steps to develop a new evaluation method. First of all, this paper reviewed the previous studies related to the LOS of urban streets and the socially requested items for a sustainable transportation system. Then this paper derived an index and weight through expert questions to select an evaluation index. Lastly, this paper compared the results according to the existing evaluation methods with the new evaluation methods through case studies. This paper used an Analytic Hierarchy Process(AHP) for importance analysis and weight selection between new evaluation items and indices, and applied a Grey System Theory(GST) for a synthetic and integrated evaluation between the selected evaluation indices. RESULTS : As a result of evaluating the LOS according to the existing evaluation methods and the integrated evaluation methods using a GST through case studies, it was analyzed that new methods' results are less than or equal to the existing evaluation methods; and as a result of applying a weight between evaluation indices according to AHP, it was noticed that the total score seems to rise more when the LOS in the existing evaluation is calculated lower. It was analyzed that the LOS calculated by reflecting the newly established evaluation items and the importance between indices in this study has difference from the LOS of the existing urban streets. CONCLUSIONS : It is expected that this evaluation method can diagnose the current conditions when establishing a future sustainable traffic system and can be used for the measurement of the sustainability effects of the improvement plans and so on.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.37-47
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• 2010

This research is aimed at comprehensively evaluating the condition of a road surface of a highway in satisfaction of its users. This research conducted an overall evaluation of a road surface condition by adding qualitative data, or a driver's satisfaction to the existing quantitative elements, whereas the existing research put its focus on a correlation analysis with quantitative factors and qualitative factors through a statistical method. As for an evaluation method, this research conducted an overall evaluation by using Grey System Theory which makes possible an integrated evaluation. The analyzed results make it possible to diagnose the current conditions of each section of object roads and to predict the potentially changeable conditions for the time to come. In addition, these analyzed results could hopefully be applied to the maintenance of freeways through diverse methods. It is hoped that the evaluation of a road surface condition of a highway in satisfaction of its user could be helpful to keeping up the satisfaction of a driver and passenger on the highway by more than a certain level. In addition, the analyzed data on the influence of data value observed by comprehensively evaluating a variety of elements could be used as a secondary means of the decision-making process in relation to road maintenance. On top of that, it could be used as a means of improving road maintenance system and offering the improved driving environment of the highway.