• KIISE Transactions on Computing Practices
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• v.21 no.3
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• pp.223-238
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• 2015

Ramp metering is the most effective and direct method to control a vehicle entering the freeway. This paper proposed the new density-based ramp metering method. Existing methods that use the flow data had low reliability data and can have various problems. Also, when the ramp metering was operated by freeway congestion, the additional congestion and over-capacity can occur in the ramp. To solve this problem with the existing method, the proposed method used the density and acceleration data of the freeway and considered the ramp status. The developed strategy was tested on Trunk Highway 62 west bound (TH-62 WB) in Minnesota Twin-City and compared with Stratified Zone Metering(SZM), which had been operating in the Twin-City freeway. To constitute the experiment environment, the VISSIM simulator was used. The Traffic Information and Condition Analysis System (TICAS) was developed to control the PTV VISSIM simulator. The experiment condition was set between 2:00 PM and 7:00 PM, Oct 5th, 2014 during severe traffic congestion. The simulation results showed that total travel time was reduced by 20% for SZM. Thus, we solved the problem of ramp congestion and over-capacity.

• Journal of Navigation and Port Research
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• v.40 no.1
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• pp.35-41
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• 2016

Port congestion has been recognized as one of the critical factors for port service competitiveness and port selection criteria. However, congestion ratio, the congestion index currently used by Korea, plays a very limited role in shipping companies' and shippers' selection of port and port authorities' decision making regarding port management and development. This is mainly due to the fact that this ratio is only calculated as the ratio of the number of vessels by each port. Therefore, this study aims to measure service level related to vessel entry and departure in Korea ports by evaluating waiting ratio(WR) according to terminals and vessel types. The results demonstrate that the waiting ratio of containerships and non-containerships is less than 4% and 15% respectively, which satisfies the reasonable level suggested by the UNCTAD and OECD. Port of Pohang is revealed to have the highest WR of 57% and among the terminals, No. 1 Terminal of the Shinhang area has the highest WR. In terms of ship types, WR of Steel Product Carrier is highest, followed by General Cargo Ship and Bulk Carrier at the Pohang Shinhang area. In addition to WR, berth occupancy ratio as well as the number and time of waiting vessels can be utilized to evaluate service level by ports and terminals from port users' perspective, and furthermore, to improve the port management and development policy for port managers or authorities.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.57-69
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• 2007

The most important problem in logistic activities may be to decrease the transportation efficiency due to the traffic congestion in urban areas. The traffic congestion reduces the average travel speed of freight vehicles, and then increases the travel time. These problems can lead the logistic system to be inefficient. As a result, it causes an increase of transportation costs. In addition, the increased cost is a main barrier for the transition to an advanced logistic system. This study focuses on the analysis of key factors choosing commercial freight vehicles using Logistic regression-analysis with RP (Revealed Preference) data to solve the increase of private freight cars and transportation costs. Additionally, this paper presents policies to promote good use of commercial freight vehicles based on the results of this study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.214-227
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• 2003

Developing an application, it is difficult to catch an exact requirement with the conventional text-based method. It has also problems in verification and analysis at each developing stage. Therefore, if an adjustment is required with an error and change of requirement, a bad effect happen in the whole system. In this case, it also affect adversely on the developing cost and period. Meanwhile, if an analysis or verification is performed, the possibility of an error frequency reduces. Thus, not only is it easier to correct the error but also add an new requirement. This thesis embody a TCP/IP congestion control algorithm with SDL which provides automatically graphic interface, verification and analysis to each developing stage. Using SDL gave a clear representation embodiment in each developing stage and easiness of adjustment due to changing requirements or correcting errors. In addition, the stages of protocol have been certified in a simulation by verification of MSC and the results showed a possibility of developing a better TCP/IP protocol.

• Journal of The Korea Institute of Healthcare Architecture
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• v.28 no.1
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• pp.63-74
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• 2022

Purpose: The purpose of this study is to present an evacuation performance analysis model that can derive vulnerable evacuation spaces with considering the movement behavior as per the elderly groups in the event of a fire in a geriatric hospital. Methods: The evacuation characteristics of geriatric hospital users were investigated through the review of precedent studies. First, the occupant conditions and the evacuation scenario were set to analyze a study target hospital. Then, the evacuation simulation was carried out considering the group types and the density of each group. Finally, an evacuation performance analysis model according to the group type was presented based on the simulation results. Results: The results of this study are as follows: (1) The evacuation performance according to the group type is to be clarified through the suggested study model. (2) It is necessary to secure a ramp or an emergency elevator to distribute the evacuation personnel at the design stage because congestion occurs due to collisions between evacuees on the stairs and delays the evacuation time. (3) It is necessary to consider the evacuation stairs and openings of sufficient size by analyzing the frequency of congestion occurrence and the escape routes of occupants in advance to identify the space where the evacuation flow overlaps. Implications: It is expected that the study result is to be used as primary data for studies that consider the elderly and clustering evacuation behavior in the event of a fire in a geriatric hospital.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.60-67
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• 2000

The success of road haulage, in dominating the surface movement of freight, is now threatened by increased traffic congestion, falling average motorway speeds and rising in logistic costs. As a result, Government as well as companies, which use or operate logistics service, is now looking to rail to provide an alternative. First, we surveyed the bottlenecks and desired betterments to rail transport, which were indicated by rail and road transport users. Through the analysis of customers' needs survey. this paper is focused in the basic framework fur the rail freight transport, which could be helped to promote the efficiency associated with moving freight by rail.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.9-12
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• 2000

본 논문에서는 기존의 지상 ATM망의 제어기법을 바탕으로 위성망으로 확대 적용할 수 방안으로 기존의 지상 ATM망의 막힘제어 기법중 ERICA스위치 알고리즘을 적용하였으며, 기존의 ERICA스위치 알고리즘은 지상과 위성간의 긴 전파지연시간을 고려하지 않아 위성내의 막힘을 알려주는 정보가 지구국까지 전달되어 다시 위성에 전달될 때 위성의 막힘 상태변화로 인한 손실이 발생할 수 있다 본 논문에서는 이러한 손실을 피하기 위한 제어구조에 대해서 다루었다.

• Journal of the Korean Mathematical Society
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• v.35 no.3
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• pp.727-740
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• 1998

Controlling traffic lights at a bottleneck, in [5] a time of open passage is called optimal, if it minimizes the first moment of the asymptotic distribution of the queue length. The discussion of the first moment as function of the time of open passage is based on an analysis of the behavior of a fixed point when varying control parameters and delivers theoretical and computational aspects of the traffic problem.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1816-1824
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• 2011

Recently, with traffic SOC investment policy changing from road-centered to railway-centered according to environment-friendly and sustainable development, issues regarding overlapping and overinvestment of traffic facility have been raised. Regarding investment of various traffic facilities of which departure and destination are similar to each other, academia, civic organizations, government, etc. are recognizing problems including overlapping investment of budget, environmental destruction, etc., but not suggesting definite solutions. Objective transportation network analysis is required because various positive effects including solutions of delay/congestion may occur due to provision of alternative way and distribution of the amount of traffic when accidents occur, as well as negative effects suggested by some of civic organizations in various transportation facility investment of similar departure and destination. Hereupon, this study tries to suggest a tool that can objectively evaluate interrelations of transportation network by applying multi-criteria analysis including economic feasibility regarding analysis of interconnections between and within means of transportation.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.836-842
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• 2007

Recently it is a tendency that Diesel rolling stock is committing in the commuter's train route of the suburb for solving commuting traffic congestion. It has advantage which expense of diesel rolling stock is relatively cheaper than electric rail car or high-speed train. In addition, it can be using the exist route without large-scale facility investment. Because of this advantage, the demand of diesel rolling stock occupy regular portion from overseas railway car market. GM/RT 2100 specifies the loads vehicle bodies shall be capable of withstanding, identifies how material data shall be used and presents the principles to be used for design verification by analysis. Therefore, in order to fulfill the structural requirements, Rotem Company has carried out Finite Element Analysis (FEA) to verify whether the carbody structure has enough strength to withstand the loads specified by GM/RT 2100. This research contains the results obtained by the analysis. The analysis was carried out using I-DEAS 12 NX Series