• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.265-275
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• 2023

The purpose of this paper is to devise an optimal route allocation algorithm for automated vehicle(AV) in monitoring quality of road infrastructure to support the road safety. The tasks of an AV in this paper include visiting node-links at least once during its operation and checking status of road infrastructure, and coming back to its depot.. In selecting optimal route, its priority goal is visiting the node-links with higher risks while reducing costs caused by operation. To deal with the problem, authors devised reward maximizing algorithm for AVs. To check its validity, the authors developed simple toy network that mimic node-link networks and assigned costs and rewards for each node-link. With the toy network, the reward maximizing algorithm worked well as it visited the node-link with higher risks earlier then chinese postman route algorithm (Eiselt, Gendreau, Laporte, 1995). For further research, the reward maximizing algorithm should be tested its validity in a more complex network that mimic the real-life.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.4
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• pp.54-62
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• 2008

International organizations related to air transport such as ICAO, IATA, ACI are forecasting that the number of passenger will grow about 4.4% annually up to 2015. Therefore, the innovation of given system technology and operation procedure is required in global scale to cope with the increase of air traffic demand. CNS/ATM infrastructure based on satellite is considered to play key role in order to solve the problems due to the dramatic increase of air traffic demand over the world. Free flight concept in the air transport operation has been proved with CNS/ATM infrastructure especially in USA and Europe. Therefore, it is necessary to develop key technologies to overcome technology gap and to secure international competitiveness in Korea. ADS-B is an important issue, and new element technologies should be considered as essential items which were shown in Capstone project. Nowadays, the free flight concept is combined to Air Transport Road Map such as NextGen project in USA, SESAR in Europe. In this process, free flight is included in the concepts such as ATM(Air Traffic Management), aviation security and safety, environmental protection and economy development, wide area weather variable reduction service, information integration and application between the related authorities (civil/military) etc. The purpose of research is to establish mid-term and long-term infrastructure plan and strategy for free flight realization in Korea. The analysis of action target and equipment construction status, phase construction plan of infrastructure has been performed by considering mid-term and long-term free flight plans of USA and Europe.

• Journal of Communications and Networks
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• v.11 no.5
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• pp.518-528
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• 2009

IEEE 802.11 wireless local area network (WLAN) has become the prevailing solution for wireless Internet access while transport control protocol (TCP) is the dominant transport-layer protocol in the Internet. It is known that, in an infrastructure-based WLAN with multiple stations carrying long-lived TCP flows, the number of TCP stations that are actively contending to access the wireless channel remains very small. Hence, the aggregate TCP throughput is basically independent of the total number of TCP stations. This phenomenon is due to the closed-loop nature of TCP flow control and the bottleneck downlink (i.e., access point-to-station) transmissions in infrastructure-based WLANs. In this paper, we develop a comprehensive analytical model to study TCP dynamics in infrastructure-based 802.11 WLANs. We calculate the average number of active TCP stations and the aggregate TCP throughput using our model for given total number of TCP stations and the maximum TCP receive window size. We find out that the default minimum contention window sizes specified in the standards (i.e., 31 and 15 for 802.11b and 802.11a, respectively) are not optimal in terms of TCP throughput maximization. Via ns-2 simulation, we verify the correctness of our analytical model and study the effects of some of the simplifying assumptions employed in the model. Simulation results show that our model is reasonably accurate, particularly when the wireline delay is small and/or the packet loss rate is low.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.3
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• pp.301-309
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• 2007

Netherlands had suggested a uniform system to standardize and simplify EDI systems relating to the Arrival/Departure, stay, and clearance of ships, persons, and cargoes for the Facilitation of International Maritime Transport to the International Maritime Organization(IMO). Republic of Korea proposed the Framework of XML-based Single Window System for the simplified clearance of ships to the 32nd session of Facilitation Committee of the IMO. Accordingly the authors studied that the XML Infrastructure for Single Window efficiently supports the Single Window service and the business collaboration between business entities of logistics. The proposed XML Infrastructure designs to support the various document format translation and to easily manage. Therefore business entity using the proposed system has the effect of downing the resource and costs on using Single Window.

• International Journal of Railway
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• v.5 no.4
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• pp.135-138
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• 2012

The article suggests criteria of dividing transport systems into systems of limited and open access. Possibilities of implementing principles of the open access in conjunction with the adaptive control at the railway transport have been analyzed. The author makes a grounded conclusion that the development of transport systems based on the open access and adaptive control can play a positive role in overcoming the global instability of the economy and form prerequisites of its stable grows.

• East Asian Economic Review
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• v.25 no.1
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• pp.3-31
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• 2021

This paper estimates the effects of transport (road and rail) & energy and ICT infrastructure (telephone, mobile, and broadband) on GDP growths in neighboring countries as well as own countries. We confirm positive direct contributions of infrastructure, access to Internet, and human capital on economic growth. The spatial panel regression models indicate that there exist positive externalities of the broadband infrastructure and human capital, and these results are robust regardless of the choice of spatial weight matrices. Our findings on spillover effects of infrastructure suggest the key role of neighboring countries' infrastructure on own country's economic growth.

• Wind and Structures
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• v.26 no.1
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• pp.35-43
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• 2018

This paper describes the effect of different testing parameters (configuration of infrastructure and truck position on road) on truck aerodynamic coefficients under cross wind conditions, by means of a numerical approach known as Large Eddy Simulation (LES). In order to estimate the air flow behaviour around both the infrastructure and the truck, the filtered continuity and momentum equations along with the Smagorinsky-Lilly model were solved. A solution for these non-linear equations was approached through the finite volume method (FVM) and using temporal and spatial discretization schemes. As for the results, the aerodynamic coefficients acting on the truck model exhibited nearly constant values regardless of the Reynolds number. The flat ground is the infrastructure where the rollover coefficient acting on the truck model showed lowest values under cross wind conditions (yaw angle of $90^{\circ}$), while the worst infrastructure studied for vehicle stability was an embankment with downward-slope on the leeward side. The position of the truck on the road and the value of embankment slope angle that minimizes the rollover coefficient were determined by successfully applying the Response Surface Methodology.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2007.10b
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• pp.44-48
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• 2007

In recent years, the relationships and inter-dependencies between the countries in East Asia have deepened, and the vision for regional cohesion such as the East Asian Community have been gradually elaborated. A Grand Design for Northeast Asia is one of these comprehensive visions that aim to improve and develop international infrastructure through cooperation in the field of transportation, energy, environment, and information technology. This study paid attention to the possibility for a system for regional cohesion and cooperation in spatial development in East Asia, and analyzed the roles of the ESDP according to the requirements of the East Asian situation. As a result, it was understood that while the development of infrastructure is a main stream in the case of the regional cohesion in East Asia, the cooperative visions for the conservation of natural and cultural heritage, which are being positioned as an important policy in the EU, have not been seen. It is a very important subject to promote the policy cohesion/cooperation on the conservation and management of natural/cultural heritage and the development of tourism infrastructure for the sustainable development of East Asia, considering the trends in the growth of the interchange population and tourism market in East Asia. It was discussed that the role of research networks like the International Landscape Architectural Symposium of Korea, China and Japan is becoming important in supporting this policy cohesion and in grasping the present conditions and trends of the spatial development of these counties.

• Journal of Korean Society of Rural Planning
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• v.25 no.1
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• pp.51-65
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• 2019

This study developed diagnostic system to understand the level of welfare cultural service and infrastructure in rural areas. The applicability was reviewed through the Delphi survey and the sample survey of 60 villages. The diagnostic indicators consist of three areas: the demand area, supply area, and delivery area. The demand area consists of 8 indicators, 25 indicators for welfare services and infrastructure (healthcare, social welfare) and 32 indicators for cultural services and infrastructure (culture, education, leisure sports). The service delivery area was divided into service supply area access and traffic accessibility (public transport use status and rural transport model status) by each indicator. A diagnostic system was applied to 60 villages. Services and infrastructure for rural welfare and culture were supplied more in the Si area than Gun area. The delivery area was easier to access the Gun area than Si area. In the case of traffic access, public transportation was more frequently used in the Si area than Gun area, and the rural transportation model was found to have a relatively large amount in the Gun area compared to Si area. The diagnosis system about services and infrastructure for rural welfare and culture will provide information necessary for establishment and decision making of regional development policy taking into account characteristics of rural areas in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.211-224
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• 2022

In this study, factors affecting the efficacy of EV charging infrastructure improvement were investigated for EV users on Jeju Island. This study analyzed satisfaction with the EV charging infrastructure and demographic factors that affect the efficacy of EV charging infrastructure improvement. Factors found to affect the efficacy of EV charging infrastructure improvement include a sufficient number of charger installations, the speed in using EV chargers, the ease of obtaining additional information about charging, and fast customer service for faulty chargers. It was also confirmed that demographic factors such as user's housing types had a significant effect. This study contributes to verifying user satisfaction with the construction of EV charging infrastructure throughout Jeju Island.