• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6D
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• pp.779-784
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• 2011

Freeway FFS (Free-Flow Speed) under the state of LOS (Level of Service) A has been regarded as a homogeneous state to all levels of traffic volume. The features of low-density FFS is served as the basic data for a decision on limited maximal speed, accident analysis, simulation modeling etc. A few researches for the macroscopic characteristics of design and operation speed have been reported, and any study for the microscopic features of freeway free-flow speed under the state of low density has not been done. Therefore, the characteristics of low-density FFS according to the level of traffic volume (1-3 veh/30 sec) and daily hour periods (0-5, 6-8, 9-11, 12-19, 20-23) is microscopically analyzed in this study with huge volume and speed data. It was found that speed distributions are changed and show different behaviors under the conditions of traffic volume levels and daily time periods. V85s (85th percentile speed) at early morning and night periods decrease when levels of traffic volume increase, whereas V85s at day time do not show considerable differences. Especially, FFSs of levels of traffic volume at early morning and night periods, despite low density, is analyzed as heterogeneity, but homogeneity at day time.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.5
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• pp.1-10
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• 2014

This research focuses on the warrants for the Two-Way Left-Turn Lanes (TWLTL). Using a microscopic traffic simulation tool, two key parameters were investigated herewith. One is a wide range of the Design Hourly Volume (DHV), reflective of recent Korean roadway volume characteristics, that is conventionally reduced from the Average Daily Traffic (ADT). The other is driveway spacing, the length of the middle-lane section where two conflicting left-turn demands often compete for space. In addition, unlike previous researches, the way and the procedure the TWLTL operation is realized in the VISSIM S/W with its add-on application such as VISVAP is clearly stated and described in detail. According to the result of simulations for 10 volume scenarios, as expected, the higher the volume level is, the more delay the left-tuner experience. The Level Of Service (LOS) for most cases was in the range of C and D based on the non-signalized intersection LOS criteria. Furthermore, the TWLTL was found operable up to the volume level of 1,116 and 1,860 vph in heavy direction (equivalent of volume level 7) for 3-lane and 5-lane facility respectively, which covers significant portion of existing two to four-lane highway volumes in Korea.

• Health Policy and Management
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• v.26 no.1
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• pp.39-50
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• 2016

Background: This study examined patient and hospital factors related to long-stay admissions in long-term care hospitals (LTCHs) among older people in Korea. Methods: We analyzed health insurance claims data, entitlement data, and institutional administrative data from the National Health Insurance Service databases between 2010 and 2012. At the patient level, we compared characteristics of patients staying in LTCHs for over 180 days (the long-stay group) with those staying in LTCHs for less than 90 days during a calendar year. At the hospital level, we examined the general characteristics and staffing levels of the top 10% of hospitals with the highest proportion of patients whose length of stay (LOS) was 180+ days (the hospitals with long-stay patients) and compared them with the top 10% of hospitals with the highest proportions of patients whose LOS was less than 90 days (hospitals with shorter-stay patients). Results: The long-stay group accounted for about 40% of all LTCH patients. People in the group were more likely to be women, aged 80+, living alone, and experiencing more than two health conditions. Compared to the hospitals with shorter-stay patients, those with long-stay patients were more likely to be occupied by patients with behavior problems and/or impaired cognition, owned by corporate or local governments, have more beds and a longer period of operation, and deliver services with lower staffing levels. Conclusion: This study found long-stay older people in LTCHs and those in LTCHs with high proportions of long-stay older patients had several distinct characteristics compared to their counterparts designated in this study. Patient and hospital characteristics need to be considered in policies aiming to resolve long-stay admissions problems in LTCHs.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.297-304
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• 2003

As the high speed rail to be opened at 2004, the. railroad will dominate over the transportation market in the Seoul-Busan corridor compared to road transport. But, it is obvious that the LOS(level of service) of railroad at 2004 will be worse in the areas that are not served KTX. For the speed-up of conventional line, it is a worldwide trend that tilting trains are served on the conventional railway line. That is the reason serving tilting trains is very efficient to use existing facilities and improve cruise time when capacity is available. In this paper, we suggest 10 routes are replaced with present operating trains(saemaeul, mugunghwa) by the tilting train.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1845-1854
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• 2007

기존의 철도용량의 개념은 하루동안 최대한 통과시킬 수 있는 최대 열차 횟수를 기본으로 하여왔다. 그러나 이러한 단순한 최대횟수는 그 사용상의 여러 가지 제한사항을 가지고 있다. 최대열차 운행횟수는 열차의 속도, 신뢰성등과 같이 고려하여야 하며, 이러한 고려는 자연스럽게 서비스수준과 같은 과거철도에서는 구체적으로 고려하지 않던 새로운 용량에 대한 접근을 요구하게 된다. 2004년에 세계철도연맹(UIC)에서 제안한 철도용량 산정절차는 이러한 측면에서 많은 점을 시사하고 있다. 새로운 절차의 한국의 지역간 철도에의 적용가능성을 검토해 본다. 본 연구에서는 2006년 11월 새로 개편된 경부선, 호남선의 열차시간표를 이용하여, 문제가 되고 있는 서울역${\sim}$시흥역 구간에 대해 UIC에서 새롭게 제시한 선로용량의 개념을 OpenTrack을 이용한 시뮬레이션을 통해 적용해보고, 이에 따라 선로 용량 산정시 적용할 수 있는 MOE를 찾아내 서비스수준(LOS)을 결정할 수 있는 방안을 제시해보고자 한다.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.587-595
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• 2013

Establishment and operation of Aids to Navigation in the process of port design, construction and management are crucial factor of maritime safety and collision prevention. According to the IMO SOLAS Chapter 5, regulation 13, the establishment and operation of maritime safety facilities are mandated for the competent authorities. The facilities of Aids to Navigations are moving to a concept of e-Navigation with state-of-the-art technology of radio navigation equipments such as AIS, DGPS and e-Loran from the traditional visual facilities (optics, shape), Although the autonomous maritime traffic system is a new trend, yet the traditional and conventional Aids to Navigation like lighthouses and beacons are still imperative for vessel's safe navigation. In this paper, for decision of service level of maritime traffic facilities to enhance the efficiency of visual navigation system management it was proposed the Aids to Navigation availability as an efficient management system incorporating the whole maritime traffic facilities under one management system. Comparison of foreign level of services and analysis of the theoretical background of them were analyzed and the proposed LOS was applied to Incheon area to evaluate the safety of navigation routes.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.67-79
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• 2017

Increasing transportation dependence on the metro system has lead to the convenience of passengers becoming as important as the transportation capacity. In this study, a pedestrian simulator has been developed that can quantitatively assess the pedestrian environment in terms of attributes such as speed and distance. The simulator consists of modules designed for 3D indoor map authoring and algorithmic pedestrian modeling. Module functions for 3D indoor map authoring include 3D spatial modeling, network generation, and evaluation of obtained results. The pedestrian modeling algorithm executes functions such as conducting a path search, allocation of users, and evaluation of level of service (LOS). The primary objective behind developing the said functions is to apply and analyze various scenarios repeatedly, such as before and after the improvement of the pedestrian environment, and to integrate the spatial information database with the dynamic information database. Furthermore, to demonstrate the practical applicability of the proposed simulator in the future, a test-bed was constructed for a currently operational metro station and the quantitative index of the proposed improvement effect was calculated by analyzing the walking speed of pedestrians before and after the improvement of the passage. The possibility of database extension for further analysis has also been discussed in this study.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.4
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• pp.20-29
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• 2014

Density is applied both three major macroscopic traffic variables (traffic volume, speed, and density) and two measures of effectiveness (MOE) for level of service (LOS) on highway (density and V/C). Especially, it is known for the most accurate MOE on evaluating the LOS of highway. Despite such importance, there is a lack of study on density relatively than other variables for its difficulty of measurement. Existing density estimation methods have some limitations such as density values of same traffic flow vary with collecting time. In this study, we researched actual density measuring method with panoramic image, after each CCTV images in the Sapaesan Tunnel on Seoul Ring Expressway are matched into one panoramic image. Analysis through the Central Limit Theorem shows that density of 24 1 km-images, which means 24 second, applies traffic situation well. That is to say that reasonable density value regardless of collecting time, and practical density which represents actual traffic flow can be taken in case of measuring density by suggested collecting cycle.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.1-12
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• 2020

In this study, the effect of the social distance maintenance and pedestrian route system was analyzed for Seoul Station, one of the multi use facilities according to the COVID-19 pandemic. For analysis, the Seoul Station pedestrian network was established through the survey of the number of passengers and CAD floor plan. A pedestrian that maintaining Social Distance was implemented using the Social Force Model. Based on this, scenario analysis was proceed. As a result, when the walking line system was installed the average walking speed decreased compared to the current situation. but the average density was analyzed that maintain the walking level of service (LOS)'C', this mean walking line system is effective, and the effect of the walking line system was proved. It can be used as a pedestrian simulation model.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.109-126
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• 2014

The level of service (LOS) of the Highway Capacity Manual (KHCM) has been used as a basic criterion at decision making processes for signalized intersections in Korea. The KHCM provides five steps for the signalized intersection analysis. Among them, lane grouping, which is the third step, significantly influence the final LOS. The current method presented in the KHCM, however, classifies a shared lane as a de facto turning lane group, even though the turning traffic of the shared lane is few. Thus, this research was initiated to provide an alternative. To this end, three alternatives were suggested, including the method based on the lane grouping presented in the U.S. Highway Capacity Manual, the method using turning ratio of shared turning lane, and the method using a threshold traffic volume in lane grouping. The feasibilities of the three methods were evaluated using a calibrated CORSIM model. Conclusively, the method using a threshold traffic volume in lane grouping outperformed.