• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.67-70
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• 2008

As a part of the project on road tunnel fire safety system development, Quantitative Risk Assessment program was developed. In this study, We carried out Quantitative Risk Assessment with this program by using a factor of cross passage interval, warning announcement time and congestion ratio etc for 1km tunnel with natural ventilation. In the case of 250m below of cross passage interval, Risk value due to warning announcement time was a slightly changed. but if cross passage interval is more than 250m, expected fatalities in the same HRR(heat release rate) was sharp increased. As a result, Quantitative Risk Assessment program which was developed in this research project is possible to risk assessment with ventilation type, cross passage for evacuation and detection system response property etc. hereafter, this program look forward to use as a tool for road tunnel performance based design.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.4
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• pp.96-104
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• 2021

Technological advances have recently led to the development of Urban Air Mobility (UAM) which is a small airplane being able to take off and land vertically. It is emerging as an alternative to transportation services in the city in the future because of the advantage of providing speed and congestion problem in cities like taxis. This research aim to study the user's acceptance of UAM. Based on the survey conducted abroad, the analysis was carried out based on th Technology Acceptance Model (TAM), by Davis et al. (1989). According to the data analysis results of 292 people, Technology, Reliability and Price effect perceived usefulness, which in turn effects Behavioral intention. UAM cannot be operated independently by a single company. It consists of partnerships with vehicles, transport platforms, batteries and other related company. To improve acceptance of UAM, it is required that collaboration between companies and support from government. And while UAM is being developed, research on acceptance from user's point of view should continue.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.339-345
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• 2018

Sunrise and sunset times differ depending on location and date. Previous studies conveniently but monotonously applied day and night times set up. This research defined the daytime and nighttime while considering the time of twilight according to the date and the location of ship collision accidents. Classifying the frequency of ship collision accidents with this standard, we conducted a chi-squared test for the difference between daytime and nighttime. The frequencies of ship collision accidents according to daytime and nighttime was compared by season, month, and time, and all of them showed statistically significant differences. The highest number of daytime ship collisions was 11.6 %, in June, and nighttime collisions peaked at 13.7 %, in December. The most frequent hour for daytime ship collisions was 0700h-0800h, at 10.2 %, and nighttime collisions peaked between 0400h-0500h, at 16.9 %. It is clear that the criteria used in previous studies cited was applied without any theoretical basis and likely only for the convenience of the researchers. It was found that results depend on what criteria are applied to the same research data. This study shows that statistical analyses of marine accidents, traffic volume, and congestion density should be carried out quantitatively while considering daytime and nighttime hours for each particular location and date.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.212-219
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• 2015

Korea's first tram (so called "tram"), which was commenced the operation on May 4, 1899 of late Joseon Dynasty and run until 1968, played a pivotal role of public transportation. However, tram as new transportation mean is being recognized as traffic congestion problem becomes issue due to geometric automobile increase and reckless urban plan after stoppage of tram service. Tram has an advantage of inexpensive construction cost and eco-friendly means compared to existing and city railway, carrying more passengers rather than existing bus, excellent connectivity of existing transportation because of easy accessible to destination in the city center. Therefore, tram, what is called "Green Rvolution of Public Transportation", has a dreaming of revival and in the process of pushing. We suggest the accident type which might break out in the early stage of tram introduction and preventive measures by surveying the accident cases of tram advanced country, and study the crossing control measures.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.337-352
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• 2005

In this paper, a fuzzy logic implementation of the random early detection (RED) mechanism [1] is presented. The main objective of the proposed fuzzy controller is to reduce the loss probability of the RED mechanism without any change in channel utilization. Based on previous studies, it is clear that the performance of RED algorithm is extremely related to the traffic load as well as to its parameters setting. Using fuzzy logic capabilities, we try to dynamically tune the loss probability of the RED gateway. To achieve this goal, a two-input-single-output fuzzy controller is used. To achieve a low packet loss probability, the proposed fuzzy controller is responsible to control the $max_{p}$ parameter of the RED gateway. The inputs of the proposed fuzzy controller are 1) the difference between average queue size and a target point, and 2) the difference between the estimated value of incoming data rate and the target link capacity. To evaluate the performance of the proposed fuzzy mechanism, several trials with file transfer protocol (FTP) and burst traffic were performed. In this study, the ns-2 simulator [2] has been used to generate the experimental data. All simulation results indicate that the proposed fuzzy mechanism out performs remarkably both the traditional RED and Adaptive RED (ARED) mechanisms [3]-[5].

• Korean Journal of Veterinary Research
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• v.24 no.1
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• pp.99-104
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• 1984

Authors observed an outbreak of porcine pleuropneumonia at a piggery in Gyeongbug, Korea, which were diagnosed on the ground of clinical and pathological findings with the following results. 1. One hundred and forty weanlings out of 200 ones died suddenly without noticiable signs during the period of 15 days. All of the dead pigs showed formy, blood-tinged discharge from the nose and mouth. 2. Main clinical findings observed from 60 alive pigs from group consisted of fever, cyanosis severe degree of dyspnea and pleuritic friction rub. 3. On hematological observation for typical 5 cases leukocytes showed marked degenerative left shift with leukopenia (10500-13070/cmm), neutropenia (7-13%) and increase in the number of band neutrophils (6-27%). 4. The most prominent and constant pathological changes observed at necropsy for dead or alive pigs consisted of fibrinous pleurisy with partial adhesion, overlying of the pulmonary surface with fibrinous menbrane and necrotic pneumonic lesions with marked edema and congestion of lung parenchyma. 5. From these results the outbreak was considered to be typical porcine pleuropneumonia, although no bacteriological isolation was attempted.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.3
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• pp.537-548
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• 2000

ATM is the effective information transmission method which multiply statistical and can accept effective the traffic of the various transmission rate. However, it can happen excessive cell loss probability and cell delay when it have temporarily overload. Therefore, it is required the effective traffic control and network resource management for which guarantee QoS(Quality of Service) in terms of users and bandwidth utilization maximization in terms of networks. In this paper, we proposed POBP(PushOut BP) scheme which mixed pushout scheme with BP(Back Pressure), reactive control scheme recommended at the ATM Forum, to guarantee QoS in two stages ATM switch networks. In proposed method, we have to understand exactly using bandwidth information in real-time and become traffic shaping. Thorough these processes, we can not only use effectively unused bandwidth, but also guarantee the fair bandwidth utilization and then can improve cell-loss possibility happened by congestion states in two stage ATM networks.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.505-510
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• 2011

The railroad freight transport has great merits that can transport mass and specific items(dangerous goods), but it takes a long time because of low accessibility to the logistics facility and the complex process of loading freight in middle station. This paper analyzed volumes and characters of each railroad freight item, and was carried out the effect of applying E&S system to Gyeongbu line containers to find the method of reducing transport time and effective container transportation. As a result of Cost-Effectiveness analysis, the block train(B/T) is reducing transport time more about 1~2 hours. The road congestion cost is saving about 2.2 billion won. And due to skipping work of organizing train, personnel and equipment expenses savings expected about 9 billion won. It is expected that the E&S system enhances the container transport service and has an effect positive influence on making a efficient method of transport. But It is necessary to estimate pre-feasibility of applying E&S system that the standard of estimating cost and benefit is required further examination.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.273-279
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• 2004

There are several ways to solve parking problem in the downtown One of them is to manage parking efficiently, that is, to raise use-efficiency of parking place and to help drivers to select easily. When we manage the parking place m the block efficiently, It can prevent disproportion that some parking space is over capacity and the other parking one is under. It causes not only the disproportion of economic efficiency but also the congestion of local road. The precondition to manage parking efficiently is to analyse the parking characteristics. In this study we found out the characteristics of parking vehicles by analyzing the turnover per parking mesh and occupancy rate And we build up total D/B by collecting every information about parking space. We developed the Parking Management System by using GIS with D/B and digital map. The efficient Parking Management System is for convenience of drivers and efficient usage of parking space. And this system is also the basic study to be developed as the total Parking Management System by upgrading every information.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.648-653
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• 2006

It pollute the earth environment with systematic industrialization. Also the congestion of cities that ignore ecosystem threaten habitation environment of human. For ESSD make progress to many researches internal and external. However we don't develop model for internal environment, research evaluation of ecological polis for this. The present research put in operation that make up question experts. In the event many people know necessity of ecological development. But It point out reality with many phases. One side we need to educate, publicize about environment. make good model and cultivate process.