• Journal of Korea Planning Association
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• v.54 no.6
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• pp.68-79
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• 2019

The purpose of this study is to propose a transit accessibility analysis method based on temporal variability of travel time. In this study, transit accessibility was defined in three levels (in transit route, spot and region unit) to present findings from different spatial scopes. Recently, Jeju special self-governing province reorganized bus system of the island. To compare transit accessibility before and after transit policy implementation, the reorganized bus system of Jeju special self-governing province was selected as a case study. This study used General Transit Feed Specification (GTFS) data format as storage public transit information, and calculated travel time using ArcGIS GTFS networks analysis tools. In the analysis of individual transit route level, we found the 3 types of accessibility changes which is increments, no significant changes and reductions and these results come from transit route change (number of transfer, distance change) rather than changes of vehicle interval. We found increases of inflow and outflow speed in most target spots and overall transit accessibility has been substantially improved in Jeju island. This study implies that accounting for temporal variability of travel time in accessibility analysis can result in more useful and sophisticated accessibility information in decision-making processes.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.448-453
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• 2003

Most urban transit companies recognize the necessity of classification for facility management Classification for urban transit facility is necessary for standardization of maintenance management. The practical application. however. is not easy because of the absence of standardization of classification for urban transit facility and the difficulty in objectification of breakdown structure. This study suggests a proposal of classification for maintenance management in urban transit facility. This study defines standardization of classification as facility, work, maintenance and attribute to manage urban transit facility. And attribute classification consist of material, equipment and document. The suggested classification can be used as a useful maintenance management tool that enables evaluation of urban transit facility by standardization. The results of this study could be used as references for related urban transit companies.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.1-11
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• 2001

Current scintigraphic tests of gastrointestinal motor function provides relevant pathophysiologic information, but their clinical utility is controversial. Many scintigraphic methods are developed to investigate gastrointestinal motility from oral cavity to colon. These are esophageal transit scintigraphy, oropharyngeal transit study, gastric emptying test, small bowel transit time measurement, colon transit study and gastroesopahgeal reflux scintigraphy. Scintigraphy of gastrointestinal tract is the most physiologic and noninvasive method to evaluate gastrointestinal motility disorders. Stomach emptying test is regarded as a gold standard in motility study. Gastrointestinal transit scintigraphy also has a certain role in assessment of drug effect to GI motility and changes alter therapy of motility disorders. Scintigraphy provides noninvasive and quantitative assessment of physiological transit throughout the gastrointestinal tract, and it is extremely useful for diagnosing gastrointestinal motor dysfunction. This article reviews the current procedures, indications, significance and guidelines for gastrointestinal motility measurements by scintigraphy.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.3
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• pp.69-82
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• 2011

This paper tried to find out what the main factors are to impact on satisfaction level of transit passengers at Incheon airport. Incheon airport has made lots of transit facilities and services to attract transit passengers from neighboring airports to increase transit rate as high as advanced foreign airports such as Heathrow, Schiphol and Hong Kong. A survey was performed on 450 transit passengers resting at airport transit lounge in airside area. According to the result, it was found out to be significant factors affecting satisfaction of transit that convenience of security screening, price of duty-free product, a direction board & signage and terminal orientation among Chinese transit passengers. On the other hands, it seemed that Japanese transit passengers thought diversity of airline routes, convenient transfer flight schedule, total transit time and terminal orientation are major variables affecting their satisfaction. Considering the effect of demographic factors, Chinese passenger's satisfaction was more affected by age, travel purpose, the number of travel per year and flight destinations. However, Japanese transit passenger's satisfaction was only affected by the flight destinations, especially willing to travel to North America and Europe.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1222-1230
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• 2010

This study is about developing a transit assignment model on railway network. Current transit assignment models are mainly focused on road or urban transportation so that these models, for example, transit assignment model based on optimal strategy generates unrealistic transit assignment. Especially, since the advent of KTX, more passengers are using the transfer route containing KTX but most transit assignment models have a shortcoming that transfer is not considered or is overestimated. We present a new stochastic transit assignment model based on LOGIT considering transfer resistance.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.233-238
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• 1993

Esophageal motility was evaluated from the analysis of 10 consecutive swallows using liquid bolus containing 0.5 mCi of $^{99m}Tc$ tin colloid. We have reviewed our experience of esophageal transit study in the 20 normal volunteers and 55 patients with dysphagia that was not related to mechanical obstruction. The purpose of this study is to measure the esophageal transit in normal subjects and in patients with various esophageal motility disorders. The overall sensitivity and specificity of radionuclide esophageal transit study in detecting esophageal motor abnormality were compared with manometric results as a gold standard, which were 80% and 100% respectively. Radionuclide transit study is a safe, rapid, noninvasive test and suitable as a screening test for esophageal motor disorders.

• Journal of Korean Society of Transportation
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• v.28 no.3
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• pp.85-98
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• 2010

As transit networks are becoming more multimodal, the concept of connectivity of transit networks becomes important. This study aims to develop a quantitative model for measuring the connectivity of multimodal transit networks. To that end, we select, as evaluation measures of a transit line, its length, capacity, and speed. We then define the connecting power of a transit line as the product of those measures. The degree centrality of a node, which is a widely used centrality measure in social network analysis, is employed with appropriate modifications suited for transit networks. Using the degree centrality of a transit stop and the connecting powers of transit lines serving the transit stop, we develop an index quantifying the level of connectivity of the transit stop. From the connectivity indexes of transit stops, we derive the connectivity index of a transit line as well as an area of a multimodal transit network. In addition, we present a method to evaluate the connectivity of a transfer center using the connectivity indexes of transit stops and passenger acceptance rate functions. A case study shows that the connectivity evaluation model developed in this study takes well into consideration characteristics of multimodal transit networks, adequately measures the connectivity of transit stops, lines, and areas, and furthermore can be used in determining the level of service of transfer centers.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.860-869
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• 2011

It is very important that reduce the maintenance cost and extend life time of the urban transit EMU through effective maintenance method research. The maintenance cost of the urban transit EMU shares 60%~70% of it's life cycle cost. It means that the maintenance cost is bigger than the introduction cost of the urban transit EMU. In this study, I introduces a quality control technique to improve the urban transit vehicle reliability. I suggest the control chart using quality control technique. And the control charts apply to the Static Inverter of EMU.

• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.111-121
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• 2007

A transit assignment model can forecast the behaviors of transit users. thereby playing an important role In the evaluation of transit policies. Most existing transit assignment models are based on the models for passenger cars; therefore they cannot reflect the specific characteristics of transit modes. In addition most of the existing models are based on a single transit mode (bus or rail), and they cannot forecast the behaviors of transit users in a changing mass transportation system. The goal of this study is to overcome these problems with the exiting models and to develop a more realistic model. The newly developed model is based on mixed transit modes and is a stochastic model that can reflect the different preferences of each transit user for travel time and transfering. Data gathered from the Seoul metropolitan area's smart card are used to calibrate this model. This study is expected to be used for the evaluation of transportation policies and to attribute the development of transit revitalization strategies.

• Journal of Korean Society of Transportation
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• v.31 no.2
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• pp.20-32
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• 2013

This study is aimed at identifying the relationship of transit accessibility types to its related travel frequency in the Seoul metropolitan area. A multi-level poisson regression model is employed after categorizing transit accessibility into 18 types based on locations of residential and work workplace. Analysis results offer three policy implications in improving transit use in the Seoul metropolitan area. First, increase in transit ridership can be more effectively attained when policies concerning both competitive and complementary relationships between bus and rail transit are incorporated. Second, transfer system needs to be focused on such two modal perspectives as one travels from Seoul to suburban area and residential areas given the fact that walking accessibility to bus transit is good but that to rail transit is poor. Third, it is more effective to emphasize rail transit priority rather than bus transit, especially for the travel from suburban area to the city of Seoul in order to increase transit ridership.