• Journal of Advanced Navigation Technology
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• v.28 no.3
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• pp.288-299
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• 2024

Indonesia's Keplauan Liau region is facing limitations in the development of connected transportation infrastructure due to its archipelago nature, budget constraints, and lack of land. Transportation demand is increasing due to its strategic location in the Malacca Strait Business Triangle and many tourist visits from Singapore and Malaysia. However, due to the nature of connecting many islands, the establishment of transportation infrastructure has not been achieved. This paper aims to predict the innovations that can be brought about by the introduction of advanced air mobility (AAM) with an electric vertical take-off and landing (e-VTOL) system through analysis and application consideration of the actual situation in Indonesia's Kepulauan Liau region. In addition, it intends to contribute to national-level review and policy establishment on the establishment of innovative transportation infrastructure using AAM, reflection in infrastructure construction plans, and active global cooperation.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.279-288
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• 2018

Unlike the past, the elderly who are growing rapidly in Korea are called 'active seniors'. They prefer to live in urban silver towns despite high living cost and make their own new urban contents. The new urban contents that reflect the living characteristics of active seniors have an important impact on their choice of residential location. Therefore, the purpose of this study is to identify the location characteristics of urban silver towns, which are preferred as the main residence of active seniors, based on the urban living contents of active seniors. The location characteristics of urban silver towns considering the urban living contents of active seniors can be classified 1) public transportation, 2) nearby arterial roads, 3) culture shopping facilities, 4) medical facilities, 5) apartment complexes, and 6) natural environments. Especially, the accessibilities of medical facilities, apartment complexes, and culture shopping facilities were the main characteristics of urban silver towns. The results of this study are expected to be helpful not only the location of urban silver towns, which is the urban new content of active senior, but also for the policy on housing for the elderly.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.1
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• pp.31-43
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• 2021

In this study, approximate design optimization using various meta-models was performed for the structural design of active type deck support frame. The active type deck support frame was newly developed to facilitate both transportation and installation of 20,000 ton class offshore plant topside. Structural analysis was carried out using the finite element method to evaluate the strength performance of the active type deck support frame in its initial design stage. In the structural analysis, the strength performances were evaluated for various design load conditions that were regulated in ship classification organization. The approximate optimum design problem based on meta-model was formulated such that thickness sizing variables of main structure members were determined by achieving the minimum weight of the active type deck support frame subject to the strength performance constraints. The meta-models used in the approximate design optimization were response surface method, Kriging model, and Chebyshev orthogonal polynomials. The results from approximate design optimization were compared to actual non-approximate design optimization. The Chebyshev orthogonal polynomials among the meta-models used in the approximate design optimization represented the most pertinent optimum design results for the structure design of the active type deck support frame.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5729-5744
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• 2017

Vehicular Ad Hoc Networks (VANET) in the large-scale road section usually have typical characteristics of large number of vehicles and unevenly distribution over geographic spaces. These two inherent characteristics lead to the unsatisfactory performance of VANETs. This poor performance is mainly due to fragile communication link and low dissemination efficiency. We propose a novel routing mechanism to address the issue in the paper, which includes a competition-based routing discovery with priority metrics and a local routing repair strategy. In the routing discovery stage, the algorithm uses adaptive scheme to select a stable route by the priorities of routing metrics, which are the length of each hop, as well as the residual lifetime of each link. Comparisons of different ratios over link length and link stability further show outstanding improvements. In the routing repair process, upstream and downstream nodes also compete for the right to establish repair process and to remain as a member of the active route after repair. Our simulation results confirm the improved performance of the proposed algorithm.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.1125-1131
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• 2005

This study is based on the assumption of surface transport linkages between Korea and China. Active economic cooperation between South Korea and North Korea are expected within the near future and Russia and China have interested in the land transport linkages in Korean peninsula. How much freight demands between the two countries that has been mainly dependent on air and sea transportation so far may convert the transport mode to surface transportation are estimated. Particularly, freight demands between South Korea and China's three northeast provinces are focused. The sensitivity analysis depends on transport time and transport cost changes is included. The modal shifts is estimated to be more sensitive to the changes in transport costs than those in transport time, suggesting the importance of transport costs of rail and road. Despite the dearth of data on the surface transport operation in North Korea, the attempts made in this study to estimate the demand conversion are hope to provide reference points for potential effects of the rail and road transport connections between China and the Korea peninsula before our discussions expand to the establishment of freight transport network of the northest Asia and, moreover, the Eurasian continent.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.356-360
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• 2013

The PRT (Personal Rapid Transit) system is a new transportation system in accordance with the requirements of the passengers. Although this PRT system was proposed a long time ago, it did not hold the limelight due to the several limitations in technology. However, the research and development has been active again recently thanks to the development in technology and the review on its applicability as the means of transportation linking to the urban transit system. Although most of these recent studies in relation to the PRT are focused on the hardware such as PRT vehicles or track structures, etc., the operational aspect of it is more important than that of any other means of public transportation. Therefore, among studies on operational aspect of this PRT system, this paper shows the result of study on technology in relation to the movement of vehicle to the station where it was called by the passenger through interface of the wayside control center with the vehicle control system in case where the passenger calls a vehicle at the station.

• Structural Engineering and Mechanics
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• v.85 no.5
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• pp.607-620
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• 2023

The classical optimal control (COC) method has been widely used for linear quadratic regulator (LQR) problems of structural control. However, the equation of motion of the structure is incorporated into the optimization model as the constraint condition for the LQR problem, which needs to be solved through the Riccati equation under certain assumptions. In this study, an explicit optimal control (EOC) method is proposed based on the explicit time-domain method (ETDM). By use of the explicit formulation of structural responses, the LQR problem with the constraint of equation of motion can be transformed into an unconstrained optimization problem, and therefore the control law can be derived directly without solving the Riccati equation. To further optimize the weighting parameters adopted in the control law using the gradient-based optimization algorithm, the sensitivities of structural responses and control forces with respect to the weighting parameters are derived analytically based on the explicit expressions of dynamic responses of the controlled structure. Two numerical examples are investigated to demonstrate the feasibility of the EOC method and the optimization scheme for weighting parameters involved in the control law.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.32 no.1
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• pp.71-78
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• 2024

In this study, we reviewed access transportation, operating companies, and airport infrastructure to revitalize Cheongju International Airport. Regarding access transportation infrastructure, it is necessary to promote a railway network connecting the metropolitan inland line and the central inland region. In addition, active administrative support from local governments is required to ensure smooth progress in railway and highway infrastructure linkage projects, such as the Osong Connecting Line and Chungbuk Line, high-speed rail network promotion, and expansion of the Chungbuk Eastern Axis Expressway and Central Expressway. Regarding operator access infrastructure, continuous efforts are required to add and attract airlines based at Cheongju International Airport. Regarding airport infrastructure, the Cheongju International Airport runway needs complete resurfacing due to its deterioration. Domestic passenger capacity has exceeded 6.5%, and considering the increase in import and export of high value-added goods in the North Chungcheong region, it is necessary to build and expand passenger terminals and cargo terminals. Cheongju International Airport's runway does not have enough runway length to operate large and ultra-large aircraft, so if it is extended from the existing 2,744m to 456m to 3,200m, several benefits can be expected in terms of revitalizing Cheongju Airport, such as route expansion.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.622-626
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• 2005

This paper presents an active vision system for ITS(intelligent transportation system : ITS). We have described a novel method to provide high quality imaging signals to a system that will perform passenger detection and counting in the roadway. The method calls for two co-registered near-infrared cameras with spectral sensitivity above (upper-band) and below (lower-band) the quality of the signal remains. We propose a novel system based on fusion of near-infrared imaging signals and we demonstrate its adequacy with theoretical and experimental arguments.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.267-273
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• 2011

Since 'The Act on Private Investment of The Infrastructure' was established in 1994, private investment as well as government's investment in transport infrastructure has been active. However investment in transport infrastructure has more risks than others' due to uncertainty both in traffic volume and in construction cost. In the current appraisal procedure of deciding transportation infrastructure investment, instead of risk management, the sensitivity analysis considering only the changes of benefit, cost and social discount rate which are main factor affecting economic feasibility is carried out. Therefore the uncertainty of various factors affecting demand, cost and benefit are not considered in feasibility study. In this study the problems in current investment appraisal system were reviewed. Using Delphi technique the major factors which have high uncertainty in feasibility study were surveyed and then improvement plan was suggested in the respective of classic 4 step demand forecasting method. The range estimation technique was also mentioned to deal with the uncertainty of the future.