• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.117-130
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• 2017

Bicycles are leading to serious accidents in the event of a side collision, and it is very important to prevent accidents in advance because it is difficult to actively deal with them in a dangerous situation. As a part of the bicycle safety driving support technology, this study establishes bicycle accidents dangerous zone based on bicycle accident data and road property information of digital map nationwide and provides timely safety information to cyclists. The point selected by using actual accident data was called 'dangerous zone', and the potential accident occurrence point generated by modeling based on this 'dangerous zone' was called 'logical dangerous zone'. As a result of the research on the Designation of Logical Bicycle Accident Dangerous Zone, the regional specificity of the bicycle accident points across the nation was generalized to the form of the logical dangerous zone through the network data.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.109-117
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• 2014

In navigation route planning systems using A* algorithms, the cardinality of an Open list, which is a list of candidate nodes through which a terminal node can be accessed, increases as the path length increases. In this paper, a method of alternately utilizing the Dijkstra's algorithm and the A* algorithm to reduce the cardinality of the Open list is investigated. In particular, by employing a depth parameter, named Level, the two algorithms are alternately performed depending on the Level's value. Using the hybrid searching approach, the Open list constructed in the Dijkstra's algorithm is transferred into the Open list of the A* algorithm, and consequently, the unconstricted increase of the cardinality of the Open list of the former algorithm can be avoided and controlled appropriately. In addition, an optimal or nearly optimal path similar to the Dijkstra's route, but not available in the A* algorithm, can be found. The experimental results, obtained with synthetic and real-life benchmark data, demonstrate that the computational cost, measured with the number of nodes to be compared, was remarkably reduced compared to the traditional searching algorithms, while maintaining the similar distance to those of the latter algorithms. Here, the values of Level were empirically selected. Thus, a study on finding the optimal Level values, while taking into consideration the actual road conditions remains open.

• Spatial Information Research
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• v.20 no.6
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• pp.109-118
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• 2012

Recent increasement of metropolitan infrastructure due to rapid expansion and development of urban areas which caused complexity and diversification of management system demands higher cost and effort to manage and maintain the facilities. The reason why it requires continuous and systematic management by national government is that the infrastructure facilities takes important role as it is directly related to public's living. Thus this study suggests an efficient management plan for increasement of work efficiency, cost reduction, and time saving by introducing 3D geospatial information system for water distribution reservoirs which is managed by the Office of Waterworks Seoul Metropolitan Government. This study evaluates and quantifies the range of work improvement using the 3D GIS technology through carrying out a survey targeting people in charge of the Office of Waterworks Seoul Metropolitan Government and other 8 offices. From the result of the research, applying the 3D-GIS improves by 90.32%, 93.55%, and 91.61% in the area of work efficiency, cost reduction, and time saving respectively. Consequently, using 3D GIS in future management of infrastructure could be used as a way of producing base data which supports administrative decision making through statistical and case analysis based on continuous data management. Also it would contribute to improving work efficiency by improving management system through preventing data omission.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.1-9
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• 2012

This study proposed a method to determine the number and location of bus information terminals (BIT), which is a device to provide passengers with bus arrival time at bus stops in a Bus Information System (BIS). In low-density area, it is not efficient to survey bus demands such as the number of passengers at all bus stops due to time and cost. This kind of a survey would, however, competently cover all bus stops if performed inside the bus. The number of riding-on and -off passengers is observed for every bus stop, and this data collection is repeated over all day. Data obtained from the survey are aggregated each bus stop. This study defines Utility Index (UI), an aggregate each bus stop. Bus stops are ranked according to UI and determined for a BIT within budget limitation. As a case study, a bus line in Jeju island, Korea, was dealt with. This case showed that the more aggregate the better data quality. This study is expected to contribute to solving a location problem of BITs in a BIS.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.48-56
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• 2012

One kind of crowdsourcing techniques which allow drivers to collect and provide traffic information using smartphones and applications is being introduced to ITS system as well. The introduction of crowdsourcing techniques requires changes in the existing ITS based on Insourcing which provide traffic information generated by detectors through VMS. ITS Information have had two problems, one is the high cost and the other is an interrupted service. Experts expect crowdsourcing technique which is created SNS, will overcome problems of ITS. But, there are not many examples and research results. Crowdsourcing technique was utilized in Jeju ATMS project to install ITS on the coastal round roads around Jeju since ITS to install point detectors turned out to be non-economic method in case of the coastal round roads with low traffic volume. However, there existed links in which traffic information cannot be generated as there were no smartphone users (crowds) even in the cost-effective crowdsourcing techniques, which indicates the fact that the crowdsourcing method is suitable for urban roads with many smartphone users, but not for local minor roads. On the contrary, insourcing-based ITS is considered to be non-economic method in applying to all roads in the city, but it can be effectively utilized in the local minor roads. Accordingly, Inter-sourcing based ITS operating system in which insourcing is connected with crowdsourcing was suggested in this study.

• Journal of Korea Port Economic Association
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• v.23 no.1
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• pp.163-193
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• 2007

Jeon-buk is well equipped for the growth of the logistics industry as it is the center of inland and marine traffic. However, it was not activated because of the infrastructure insufficiency. This paper surveyed the logistics industry facilities, interviewed people who are engaged in its business, researched into their business difficulties and the problem of the logistics industry of Jeon-buk. As a result of research, this paper makes an alternative plan for the development of the logistics industry of Jeon-buk area.

• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.151-162
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• 2002

The object of this study is to develop an operating time prediction model for expressways using toll collection data. A Prediction model based on modular neural network model was developed and tested using real data. Two toll collection system(TCS) data set. Seoul-Suwon section for short range and Seoul-Daejeon section for long range, in Kyongbu expressway line were collected and analyzed. A time series analysis on TCS data indicated that operating times on both ranges are in reasonable prediction ranges. It was also found that prediction for the long section was more complex than that for the short section. However, a long term prediction for the short section turned out to be more difficult than that for the long section because of the higher sensitivity to initial condition. An application of the suggested model produced accurate prediction time. The features of suggested prediction model are in the requirement of minimum (3) input layers and in the ability of stable operating time prediction.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.321-331
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• 2017

The objective of this study is to analyze the factors affecting the pedestrian accidents of roundabout near schools. To this end, this study has focus on the comparative analysis of pedestrian accidents across different school areas. The traffic accident data from 2007 to 2014 are collected from TAAS data set of Road Traffic Authority. To develop the pedestrian accident rate model, the linear regression model has been utilized in this study. 28 explanatory variables such as geometry and traffic volume factors are used. The main results are summarized as follows. First, the null hypotheses that the number of pedestrian accidents are the same are rejected. Second, 5 multiple linear regression accident models with higher statistical significance (adjusted $R^2$ of 0.651~0.788) have been developed. Third, while the common variables of 3 models (model I~III) related to school location are evaluated to be the pedestrian island, crosswalk, types of roundabout, elementary school and bus stop. Fourth, while the common variable of 3 models (model III~V) related to near school area or not is evaluated to be pedestrian island, type of roundabout, sidewalk, elementary school, speed hump, speed limit sign and number of entry lane. As a result, the installation of pedestrian islands and crosswalk might be expected to decrease the number of pedestrian accidents near schools.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.40-47
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• 2020

Various technologies, systems, and legal systems are applied to prevent and quickly respond to fire disaster; nevertheless, the damages to life and property caused by fires are not reduced every year. For managing fire disaster, generating spatial information-based safety status map and procuring suitability of attribute information for each position information are essential. The safety status map is generated by deriving the fire safety status assessment factors, indexing, and locating the surveying results through various methods. In this paper, we deal with derivation of building fire safety assessment factors for 3D safety status map. At first, we survey the foreign and domestic fire assessment model cases and its factors, and analyze the applicability of Korean 3D fire safety status map. Next, assessment factors for fire safety assessment model are derived. Assessment factors are derived and categorized by their information collecting activity; factors that can be accessed through basic building information and factors that can be accessed through field survey. As a derivation result, 14 assessment factors were derived over five categories(Industry Risk, Structural Risk, Fire Fighting Facility, Fire Dangerousness, Fire Response Status).

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.257-266
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• 2010

The purpose of this study was to determine the effect of post types and sizes on fracture resistance in immature tooth model with various restorative techniques. Bovine incisors were sectioned 8 mm above and 12 mm below the cementoenamel junction to simulate immature tooth model. To compare various post-and-core restorations, canals were restored with gutta-percha and resin core, or reinforced dentin wall with dual-cured resin composite, followed by placement of D.T. LIGHT-POST, ParaPost XT, and various sizes of EverStick Post individually. All of specimens were stored in the distilled water for 72 hours and underwent 6,000 thermal cycles. After simulation of periodontal ligament structure with polyether impression material, compressive load was applied at 45 degrees to the long axis of the specimen until fracture was occurred. Experimental groups reinforced with post and composite resin were shown significantly higher fracture strength than gutta-percha group without post placement (p < 0.05). Most specimens fractured limited to cervical third of roots. Post types did not influence on fracture resistance and fracture level significantly when cement space was filled with dual-cured resin composite. In addition, no statistically significant differences were seen between customized and standardized glass fiber posts, which cement spaces were filled with resin cement or composite resin individually. Therefore, root reinforcement procedures as above in immature teeth improved fracture resistance regardless of post types and sizes.