• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1217-1226
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• 2000

Traditionally, Mobile Teletraffic model consists of two sub-models, i.e. the network traffic model and the traffic source model. In this paper, we present the traffic source model by developing MobCall (Mobile Call Simulator) which analyses various mobile wireless environments based on regional characteristics that the base stations are located. User mobility is presented by regional average vehicle speeds and the transportation share rate. Moreover, the user mobility on subway, which is increasing in urban area, is considered in MobCall. And also, user's movements on highway are considered in MobCall. The object-oriented simulation platform, C++SIM, is used to implement MobCall. Using MobCall, the accumulated number of calls in residential and commercial regions, the handoff rate with respect to traffic sources of Seoul, the handoff rate on highway, and the handoff rate according to the call duration are presented. MobCall enables the simulation of dynamic handoff buffering and functional entity control of one base station according to the changes in user's calling pattern at the design phase. Also, when a new town is under construction by a detailed plan, MobCall is used to design the mobile network with regional characteristics and user mobility considered.

• Journal of Korean Association for Spatial Structures
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• v.13 no.2
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• pp.101-109
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• 2013

Children are out future society members but they are not well cared to be safe from various accidents. This is due to facilities were installed upon the children's for adults which can not provide safe traffic environment for children's schooling who are not fare enough experience and matured. "The Rule of declaim for school zone and it's Management"was established in the year 1995 based on the article 11 by the "Road Traffic Low". And 15,136 school zone declared by the above rule. In this study, four elementary schools located in Nowon-gu are selected and analyzed about state of elementary school, scope of school zone, installation of street furniture, and safety signs. The analysis showed that scope of school zone is currently set in 150-meter though the regulation is within 300-meter radius. Therefore, expansion of the scope is required. It is necessary to take control of vehicle during commuting times and holograms which can be noticed in school zone have to be installed as well. Through these improvements, safety zone will be offered to children effectually.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.1-13
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• 2017

A national highway takes on an arterial roadway role between regions. It's traffic volume of minor approach is very lower than mainline because most of the traffic of national highway consists of through traffic. This means an actuated signal operation is more efficient on the national highway than pre-timed signal. actuated signals have detections on some or all movements except the mainline. In spite of these effects have been evaluated in previous studies, widespread propagation of actuated signal operation has not made so much in Korea. Because there are so many problems to use actuated signal as it is in side of roadway facilities. In this study, improved a actuation system for the national highway and evaluated it with field implementation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.1-11
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• 2013

This research proposed integrated expressway traffic management strategy using ramp metering and toll mainline metering. This research suggested a traffic signal optimization model for integrated operation of ramp and mainline metering based on Demand-Capacity Model that is used to optimize allowable input volume for ramp metering in FREQ model. The objective function of this model is sectional throughput volume maximization, and this model can calculate optimal signal timings for mainline metering and ramp metering. This study conducted an effectiveness analysis of integrated metering strategy using PARAMICS and its API. It targeted Seoul's Outer Ring Expressway between Gimpo and Siheung toll gate. As a simulation result, integrated operation of mainline and ramp metering provided more smooth traffic flow, and throughput volume of mainline increased to 14% in congested section. In addition, a queue of 400 meter was formed at metering point of toll gate. This research checked that integrated traffic management strategy facilitates more efficient traffic operation of mainline and ramp from diffused traffic congestion.

• Journal of Trauma and Injury
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• v.34 no.4
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• pp.263-269
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• 2021

Purpose: There have been increasing concerns about serious traffic accidents on highways. The purpose of this study was to analyze factors affecting traffic accidents on highways and the severity of the resulting injuries. Methods: This retrospective study was conducted at a regional trauma center. We reviewed 594 patients who had been in 114 traffic accidents on highways from January 2018 to June 2020. We collected demographic data, clinical data, accident-related factors, and meteorological data (weather and temperature). Results: Environmental risk factors were found to be significantly associated with the incidence of traffic accidents on highways. Injury severity and the death rate were higher in sedans than in any other type of vehicle. Tunnels were the most common location of accidents, accounting for 47 accidents (41.2%) and 269 injured patients (45.3%). The injury severity of individuals riding in the driver's seat (front seat) was high, regardless of vehicle type. Three meteorological risk factors were found to be significantly associated with traffic accidents: rainy roads (odds ratio [OR] 2.08; 95% confidence interval [CI] 1.84-3.29; p=0.01), icy or snowy roads (OR 5.12; 95% CI 2.88-7.33; p<0.01), and foggy conditions (OR 2.94; 95% CI 2.15-4.03; p<0.05). Conclusions: The injury severity of patients was affected by seat position and type of vehicle, and the frequency of accident was affected by the location. The incidence of traffic accidents was strongly influenced by meteorological conditions (rain, snow/ice, and fog).

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.394-396
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• 2005

IEEE 802.11를 비롯한 여러 무선 네트워크에서는 multi-rate을 활용한 시스템 성능향상에 관한 연구가 진행되고 있다. 그 중에 한가지 연구결과로 제안된 방법이 rDCF.이다. 만약 Mesh 네트워크에서 rDCF를 동작시킨다면, 시스템 throughput의 증가, Packet delay의 감소와 항께 채널상태에 따라 포워딩 전략을 다르게 함으로써 채널 error의 영향이 줄어들 것으로 기대해 볼 수 있다. 하지만 기존의 rDCF를 아무런 revision 없이 Mesh 네트워크에 적용하기에는 spatial reuse 측면에서 비효율적이다. Mesh 네트워크에서는 외부 네트워크와 access point 지점이 되는 portal쪽으로 traffic이 집중되는 것이 일반적이므로 portal에 가까울수록 traffic간의 contention도 가중되므로 시스템 전체 성능에 영향을 미치게 된다. 이러한 문제를 줄이기 위하여 무선 네트워크 환경에서 spatial reuse 측면을 향상시킴으로써 동시에 진행되는 communication 수를 늘리는 방법이 있다. 그러므로 본 논문에서 rDCF의 spatial reuse를 늘임으로써 좀더 Mesh Network위에서도 효율적으로 작동할 수 있는 기법을 제시하고자 한다.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.39-43
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• 2010

The surfacing of bridge-decks are object to secure trafficability and to protect bridge face from impact load of traffic volume and other external conditions. But the deformation of pavements and cracks happen due to the damage of the bridge-decks surfacing from the increase of the traffic, short maintenance period and continuous vibration of bridge. This test is to make the 3-type high performance concrete that has different mixing ratio and is added the blast furnace slag, fly ash and silica respectively, and to compare 3-type high performance concrete of normal high strength concrete of $400kgf/cm^2$ strength through the static loading test and fatigue test. And test specimen is united floor slab and pavement for the durability of bridge.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.21-27
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• 1998

In this paper we apply routing algorithms in circuit switched networks to B-ISDN networks and investigate the performance. B-ISDN supports a wide range of services with hetrogeneous bandwidth requirements. We assume that the network supports D classes of traffic. It is modeled as a finite D dimensional Markov chain. A call is blocked on arrival if the required bandwidth is not available on the route. The shortest path routing, alternate routing and trunk reservation are considered for performance comparison. We also consider trunk reservation with restricted access control where the network reserves certain amount of bandwidths for one class of traffic that assumes a higher transmission priority. Through the method of successive iterations, we obtain the steady state equilibrium probabilities and call blocking probabilities for dynamic routing. The results can be used to design a B-ISDN network that improves network connection availability and efficiency while simultaneously reducing the network costs.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1407-1415
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• 2008

Recently, there has been growing interest in Gyongin Line demand estimation, because SMRT(Seoul Metropolitan Rapid Transit Corporation) Line 7 will be extended west by 9.8km from Onsu to meet the Gyongin Line at Bupyeong-gu Office. This study was designed to estimate the change of traffic demand in Gyongin Line before and after the completion year 2011, also provide against the economic loss caused by the derived demand from Gyongin Line to SMRT Line 7. In this paper we give preliminary results for the strategic plans for traffic demand estimation and train operating plan in Gyongin Line by analyzing transport performance of Seoul metropolitan subway, and an additional study on the transportation market and the urban development plan is needed for more accurate results.

• Journal of the Korean Society of Safety
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• v.7 no.3
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• pp.83-88
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• 1992

In This study, an attempt has been made to build a land use appraisal model as a basis for assessing the abatement effectiveness of airpollution within Seoul city due to nitrogen oxides emitted from motor trucks. Furthermore, the model is used to predict the city's traffic volum and its validity in ascertained by comparing it with the actual recorded traffic volume data. Through a series of land use planning alternatives established in this study, the abatement effective-ness of Seoul city is assessed.