• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.152-156
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• 2008

The public concept of digital broadcasting is all about anytime, anywhere and anyone. It implies that the viewing rights of digital broadcasting have to be blessed with anyone, in anywhere and at anytime. Here anyone connotes the notion included visually and hearing impaired viewers as well as the non-disabled. Considering the current circumstance, which is a milestone of digital switchover by 2012, it seems destitute of the accessibility for the disabled. Hence this study is to manage the embodiment of broadcasting accessibility in digital interactive services originated from W3C for impaired viewers in order to cotton to the unlimited contents on digital television.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.2
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• pp.125-131
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• 2014

This study is aim to investigate and propose ways to improve real condition of the accessibility compliance that is required to use mobile applications for special education student with a disabilities. Especially, expert examined some mobile applications with 12 items out of 15 mobile application accessibility guidelines from Ministry of Science, ICT and Future Planning which is helpful for people with physical disabilities such as difficulty in seeing, hearing, and upper limb. Based on the results of expert evaluation, we analyzed the problem for mobile applications without accessibility compliance and presents improvement plans for people with disabilities to use mobile applications.

• Journal of Convergence for Information Technology
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• v.11 no.4
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• pp.130-136
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• 2021

This study investigated the general characteristics of mobility disadvantaged persons with disabilities, and to suggest implications to ensure personal mobility with the greatest possible independence for the physically disabled in community. The survey questionnaire included the categories as follows: the general characteristics of the participants, the status of outing and mobility, usage of low-floor buses & taxi for the disabled, service improvement, and mobile support center. Data collected from 219 with physical disabilities were analyzed for this purpose by using descriptive statistics. The study results showed that 54.6% of the total tended to go out everyday, and 17.0% rarely. 53.4% could go out without any assistance, and the major obstacles not to go out were stairs and inconvenience of public transportation. 26.9% used low-floor buses, and 71.1% preferred to use taxi for the disabled. The average waiting time for the usage of low-flow buses and taxi was 66.57 minute and 42.65 minute, separately. 78.7% insisted that the function of mobile support center in the community should be expanded, whereas only 49.8% recognized the role of mobile support center. Based on the study results, the researchers suggested to facilitate access by persons with disabilities to mobility aids, and to improve the actual state of pedestrian environment. In addition, the function of mobile support center should be expanded to help the mobility disadvantaged persons live independently in community, thereby contributing to the promotion of their quality of life.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.175-181
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• 2012

Under unsaturated capacity conditions with balanced approach flows, roundabout gives less delay and queue length than existing signalized intersections; however, over capacity conditions with unbalanced approach flows(flow above 450 pcu/h/lane), roundabouts efficiency drops due to the short gap between entering vehicles and circulating vehicles. This study provides a roundabout Signal Metering transfer standard and operation method. In this study, a four-way-approach with one-lane roundabout is selected to compare the Signal Metering performance for the case of unbalanced flow conditions. The performance is evaluated by using SIDRA software in terms of average delay and queue length. The result shows that the Signal Metering provides substantial improvements for the case of total approach flow is 1,800~2,000 pcu/h in which the main approach flow ratio is 60~70% gives 30~40% less delay and 30~60% less queue length than normal roundabout operation. Also, it is approved that operational performance saving can be achieved when the Metered Approach is selected adjoining to the main approach in pair.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.471-478
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• 2003

In the Signalized Intersection, the capacity analysis is conducted with a large amount of input data such as road way, traffic and signal condition. but the level of service(LOS) is determined by delay estimated as a measure of effectiveness (MOE) based on this procedure. However, It is under the circumstances which are not considered for the errors caused by the uncertainty of input data in the field(the turing volumes, lane geometry, signal timing, grade of approach lane, percentage heavy vehicles, peak hour factor and arrival type etc.) as become the bases in the determination of the capacity and LOS. It includes the problem of reliability which is not verified for the capacity and LOS estimated. So, this study is to suggest the minimization of their influences by examining whether the uncertainty of input data such as the traffic volume, percentage of heavy vehicles and roadway geometry on the approach lane in the intersection under the study affects the capacity analysis and LOS determination.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.65-77
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• 2007

A two-way left-turn lane is a continuous center left-turn lane that could be used as a deceleration and refuge area for both directions of left-turning vehicles. TWLTL's have been used effectively for access management treatment when applied to a highway that has wide-spread left turning traffic demand and a high-density of side streets. In this study, an effective analysis was carried out using a computer-based simulation tool, VISSIM, in order to evaluate performance and safety effects of TWLTLs and develop a warrant. In conclusion, the results indicated that there was a remarkable decrease of through and left-turning vehicle travel time delay on the main road and improvement of traffic safety.

• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.401-409
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• 2014

This study deals with capacity expansion planning of airport infrastructure in view of economic validation that reflect construction costs and social benefits according to the reduction of passengers' delay time. We first forecast the airport peak-demand which has a seasonal and cyclical feature with ARIMA model that has been one of the most widely used linear models in time series forecasting. A discrete event simulation model is built for estimating actual delay time of passengers that consider the passenger's dynamic flow within airport infrastructure after arriving at the airport. With the trade-off relationship between cost and benefit, we determine an economic quantity of conveyor that will be expanded. Through the experiment performed with the case study of Incheon international airport, we demonstrate that our approach can be an effective method to solve the airport expansion problem with seasonal passenger arrival and dynamic operational aspects in airport infrastructure.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.33-42
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• 2007

The current left-turn split model adopted in COSMOS has an inherent limitation when a loop detector in the left-turn lanes was disconnected for a period of time. In this instance, the current model always allocated minimum green time to the left-turn phase, thus optimal split and efficient signal operation for the intersection was not guaranteed. In this paper, four mathmatical models using detector information of the intersection and four empirical models using historical profiles were developed and investigated for different traffic conditions to improve the operational efficiency of the intersection. From the model evaluation test, the empirical model using a four-week historical profile produced the least error among the eight models investigated. NETSIM simulation test results also showed that the proposed model could give significantly reduced delay time as compared to the current model. From these results, the operational efficency of the signalized intersections under the real-time control can be greatly improved by using the model proposed in case of the left-turn detector failure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.707-714
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• 2021

An important factor that causes delays at roundabouts is unbalanced traffic conditions. The majority of domestic studies have tendedto focus on the proportion of entering traffic rather than conflicting traffic in order to explain unbalanced traffic conditions. Also, there is scant research on the proper distance between a signalized intersection and a roundabout. In this study, therefore, unbalanced traffic conditions and optimal distance between two intersections were analyzed using SIDRA software based on the Gajwa-ro roundabout in Icheon, where unbalanced traffic conditions occur during afternoon peak hours, and its position is 295 m from a signalized intersection. It was found that a state of unbalanced traffic conditions in the form of conflicting traffic caused delays at Gajwa-ro roundabout, and the queuing length on each approach was removed when there was 850 m of distance between two intersections.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.3
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• pp.12-19
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• 2010

In road network, especially in urban area, inefficiency of travel time is caused by signal control and turn maneuver at intersection and this inefficiency has substantial effects on travel time. When searching for the shortest path, this inefficiency which is caused by turn maneuver must be considered. Therefore, travel time, vehicle volume and delay for each link were calculated by using simulation package, PARAMICS V5.2 for adaptation of turn penalty at 16 intersections of Gangnam-gu. Turn penalty was calculated respectively for each intersection. Within the same intersection, turn penalty differs by each approaching road and turn direction so the delay was calculated for each approaching road and turn direction. Shortest path dealing with 16 intersections searched by Dijkstra algorithm using travel time as cost, considering random turn penalty, and algorithm considering calculated turn penalty was compared and analyzed. The result shows that by considering turn penalty searching the shortest path can decrease the travel time can be decreased. Also, searching the shortest path which considers turn penalty can represent reality appropriately and the shortest path considering turn penalty can be utilized as an alternative.