• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.181-190
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• 2005

The time required for airport process is considered more important as the airports are becoming bigger. International Civil Aviation Organization mattes this international standards and recommends not to exceed it. The passenger forecasting model is developed to predict the number of passengers at the check-in counter, and the area of formalities for departure and entry. In case of forecasting the number of outbound-passengers. the patterns of show-up lead time(SLT) at the check-in counter and lag time from check-in counter to the area of departure formalities are modeled in terms of time. On the other hand, the matter of the choice of check-in counters and areas of departure formalities are modeled in terms of space. In case of forecasting the number of inbound-passengers and transfer passengers, the time of airplane movement from arrival to block on at the gate and the time of passengers required from gate to the area of formalities for entry are modeled in terms of time. While the matter of the choice of gates and the areas of formalities for entry are modeled in terms of space. The average error of forecasting outbound-passengers and inbound-passengers is respectively 15% and 10%, which are considered excellent with the 5% error of passenger reservation information as input data. Through the development of passenger forecasting models, we assure we could provide passengers with valuable service because we allocate resource such as employees and equipments according to the degree of concentration of passengers.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.17-30
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• 2002

Incident duration prediction is one of the most important steps of the overall incident management process. An accurate and reliable estimate of the incident duration can be the main difference between an effective incident management operation and an unacceptable one since, without the knowledge of such time durations, traffic impact can not be estimated or calculated. This research presents several multiple linear regression models for incident duration prediction using data consisting of 384 incident cases. The main source of various incident cases was the Traffic Incident Reports filled out by the Motorist Assistant Units of the Korea Highway Corporation. The models were proposed separately according to the time of day(daytime vs. nighttime) and the fatality/injury incurred (fatality/injury vs. property damage only). Two models using an integrated dataset, one with an intercept and the other without it, were also calibrated and proposed for the generality of model application. Some findings are as follows ; ?Variables such as vehicle turnover, load spills, the number of heavy vehicles involved and the number of blocked lanes were found to significantly affect incident duration times. ?Models, however, tend to overestimate the duration times when a dummy variable, load spill, is used. It was simply because several of load spill incidents had excessively long clearance times. The precision was improved when load spills were further categorized into "small spills" and "large spills" based on the size of vehicles involved. ?Variables such as the number of vehicles involved and the number of blocked lanes found not significant when a regression model was calibrated with an intercept. whereas excluding the intercept from the model structure signifies those variables in a statistical sense.

• Journal of Korean Society of Transportation
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• v.20 no.6
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• pp.115-128
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• 2002

Traffic engineers have developed and implemented various microscopic simulation models to verify the traffic performance and to prevent the expected problems. The existing microscopic simulation models categorize drivers into several types to reflect various drivers' driving patterns but miss the dynamics of drivers' behavior changed based upon the traffic conditions. It was found from the field data collected from two different merging sections on an urban freeway in Seoul, Korea, that the drivers' critical gap distributions are changed based on (1) the traffic density on the adjacent lane to the acceleration lane and (2) the opportunities left to merge in terms of distance to the end of acceleration lane. It was also found from the study that the drivers' critical gap distributions follow the Normal distribution. and its mean and variance change while a vehicle progresses on an acceleration lane. This paper proposes a new gap-acceptance model developed based on a set of drivers' critical gap distributions from each segment on the acceleration lanes. Through the comparison study between the field data and the results from the simulation utilizing the proposed model, it was verified that (1) the distribution of merging points on an acceleration lane to the adjacent main lane at different density levels, (2) the size of the gap accepted for merging and (3) the speed difference between the merging vehicle and the trailing vehicle at the time of merging are statistically identical to the field data at 95% confidence level.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.518-527
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• 2013

In 2011, South Korea's Ministry of Health and Welfare started a national tooth brushing room program without a pilot project. This study aimed to assess the effect of the implementation of this program in Gangneung, Korea. One-year outcomes of oral health behavior and self-reported oral symptoms in the study group after installation of the tooth brushing room were evaluated and compared with those of the control group using chi-square test. The prevalence rate of good self-rated oral health in grade 1-3 students increased from 35.7% immediately after installation to 48.9% after 6 months (p=0.031) compared to 37.3% in the control group (p=0.051). Immediately after installation of the tooth brushing room, 53.5% of grade 1-3 students in the study group brushed their teeth every day, but after 6 months, only 35.5% of students brushed daily (p<0.001) compared to 28.6% in the control group (p=0.007). The prevalence rate of bad breath in grade 1-3 students was 26.2% for the study group immediately after installation compared to 25.5% in the control group (p=0.065), but it declined 16.5% after 6 months (p=0.055). The prevalence rate of bad breath in grade 4~6 students was 14.7% for the study group after 6 months compared to 25.3% in the control group (p=0.016). We recommend the creation of a healthy school environment through a school-based tooth brushing program under the active supervision of classroom teachers and the continuous monitoring of program processes in order to promote children's oral health.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.52-63
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• 2014

This is the study on users' perception gap about the effects of leisure space development of the Han River Citizen Park according to leisure constraints and was to identify leisure constraints expressed when using Han River Citizen Park and identify perception on positive and negative impacts according to use behavior characteristics of Han River Citizen Park and leisure space development. In order to compare and analyze the perception gap about the leisure space development of Han River Citizen Park users according to leisure constraints, we classified information and resources, economic affordability, free time on leisure activities in Han River Citizen Park into high influence group and low influence group and did an in-depth analysis. The results are as follows. First, Han River Citizen Park has the nature of neighborhood use with little influence on leisure constraints such as jogging and marathon, biking etc. including walking and relaxation and was a place to visit for simple exercises. Second, in the effects according to leisure space development of Han River Citizen Park, affordable leisure activity costs and ease of access were evaluated the most highly and congestion due to increasing users, increase in administrative operating budget and management personnel were concerned the most. Third, the leisure constraints in Han River Citizen Park were affected in the order of free time, economic affordability, information and resources. There were also perception gaps in congestion due to an increase in administrative operating budget and management personnel, increase in users including improvement of various leisure opportunities and leisure levels, encouragement of pride and attachment for Han river, affordable leisure activity costs depending on the degree of the influence of leisure constraints. Therefore, this study can be said to have the meaning in that we could identify leisure constraints affecting Han River Citizen Park users and resulting perception in leisure space development and revealed that the degree of the influence of leisure constraints varies in the use behavior of leisure space development of Han River Citizen Park and perception of positive and negative development impact. In addition, in order to resolve leisure complaints according to leisure constraints, we studied the need of accompaniment of leisure space operation and management system, development of various customized programs, introduction of recreational space and facilities prioritizing public interest rather than private interest with public relations and information delivery about leisure space of Han River Citizen Park.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.603-612
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• 2010

Recently, with the advance of computing and networking technique, the high speed internet becomes widespread, however, it is still hard job to do streaming the media which requires high network bandwidth over the internet. Previous VoD system researches for streaming over the internet mainly proposed techniques that controls the QoS(Quality of Service) of the media in proportion to the network status. Though, this could be the solution for the service provider while the service user who wants constant QoS may not satisfy with variable QoS. In the paper, we propose greedy precedent frame transmission technique, GPFT, for guarantee of constant QoS. In GPFT, Streaming VoD server prefetches precedent frames and transmits the frame greedily by increasing the frame transmission rate while the available network bandwidth is high. The GPFT uses the prefetched precedent frames to guarantee the QoS while the available network bandwidth is low. The experiment result shows that the proposed GPFT could guarantee the constant QoS by prefetching the frames adaptively to the network bandwidth with the characteristic of video stream.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.45-52
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• 2004

There are many cities installing ITS(Intelligent Transportation Systems) and running TMC(Trafnc Management Center) to improve mobility and safety of roadway transportation by providing roadway information to drivers. There are many devices in ITS which collect real-time traffic data. We can obtain many valuable traffic data from the devices. But it's impossible to avoid missing traffic data for many reasons such as roadway condition, adversary weather, communication shutdown and problems of the devices itself. We couldn't do any secondary process such as travel time forecasting and other transportation related research due to the missing data. If we use the traffic data to produce AADT and DHV, essential data in roadway planning and design, We might get skewed data that could make big loss. Therefore, He study have explored some imputation techniques such as heuristic methods, regression model, EM algorithm and time-series analysis for the missing traffic volume data using some evaluating indices such as MAPE, RMSE, and Inequality coefficient. We could get the best result from time-series model generating 5.0$\%$, 0.03 and 110 as MAPE, Inequality coefficient and RMSE, respectively. Other techniques produce a little different results, but the results were very encouraging.

• Journal of Korean Society of Forest Science
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• v.77 no.4
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• pp.401-413
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• 1988

To investigate the users' activity, impact and psychology in Naejang Temple district at Mt. Naejang National Park in Korea, users' density and questionnaire survey at three major picnic areas and passenger counting at major pass were executed and environmental impacton on the site was surveyed. The total number of visitors showed stability at the level of one million persons every year after 1984. Users' impact was much severe along the main trail, the upper cablecar station and the slope from the observatory to Keumsun Valley, The maximum momentary number of users was estimated as 53,000 persons in autumn. Approximately 20% of the total number of visitor used Keumsun Valley and Weonjeok Valley area and 80% of visitors left after using only grassland and cablecar. The visitors' characteristics was similiar to the type of long-distanced national park and the main visiting purpose was to see autumn leaves. The psychological satisfaction did not very significantly as to increasing user's speace. As a result of varimax rotated factor analysis, the 1st factor, most affecting users' psychological satisfaction, was related to landscape and consisted of nature disturbance, crowdedness, noisiness, cleanness, in order of importance. The 2nd factor was related to facilities and consisted of number of toilet, number of waste-baskets, amount of drinking water, safety, in order of importance.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.21-27
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• 1999

The objective of this study is to clarify the relationship between accident rate and V/C for freeway facility. The relationship can be used as a basic reference to predict and prevent traffic accident. The traffic volume and the number of accidents from 1992 to 1997 on Shingal-Ansan Freeway were analyzed in this study to clarify the relationship. Hourly accident rate and V/C were calculated for each facility sections : basic freeway section, tunnel section and toll gate section. The accident rate models consisting of an independent variable of V/C were established by repression analysis and compared with each other. The relationship between accident rates and V/C ratios represented U-shaped pattern for all sections. The result of this study indicates that accident rates are highest in the low hourly V/C range, decrease with increasing V/C ratio, and then increase as the V/C ratio increases. The accident rate of toll gate section is in general higher than that of other sections. Although the accident rate of tunnel section is higher than that of basic freeway section when V/C is above 0.67, there is no significant difference of accident rate between basic freeway and tunnel section when V/C is between 0.5 and 0.8. Basic freeway tunnel and toll gate section have the minimum accident rate when V/C is 0.78, 0.75 and 0.57 respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.311-318
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• 2016

The VTS concept was located as a principal methods of maritime safety administration in world's major harbors and expected to become the pivotal role for the future of the maritime and harbor society with e-Navigation epoch. If recent limelight concept of big-data has been included in aspect of information gathering and analysis with various studies, it's required advanced studies to improve the information analysis capability and application range of the data that can be mining by the VTS. In this study, contrast to other studies that aimed quantitative analysis as communication number, it can be mining the time information and each of the communication VTS for the target vessel, including qualitative analysis, such as the purpose or the type of communication. This comparison across multiple items of the collected information, and presenting the VTS data mining model (VCDF) that can be analyzed for the purpose of analyzing way, type and number of communication by ship's type, also number of violations through VTS communication. First, In Busan port case, it shows frequently information service and shows frequently communicating with particular types of vessels. Second, Passive VTS carried out notwithstanding many kinds of traffic violations due to communication congestion. This arranged information can be used as data for the analysis, as possible the level of traffic for VTSO situational awareness, which pointed to the 'workloads' in 'IALA Guideline' and could be used as a database for future research of e-Navigation.