• Industrial Engineering and Management Systems
• /
• v.8 no.3
• /
• pp.194-200
• /
• 2009

This study provides a heuristic algorithm to solve the locating problem of repair service centers (RSCs). To enhance the customer service level with more satisfaction and quicker responsiveness, the locating problem of RSCs has become one of the important issues in reverse supply chain management. This problem is formulated as a zero-one mixed integer programming in which an exiting distributor will be considered to be an un-capacitated repair service center for the objective of cost-minimizing. Since logistical costs are highly interrelated with the multinational location of distributors and RSCs, the fixed cost for setting a repair service center, variable cost, transportation cost, and exchange rates are considered in this study. Recognizing the selection of un-capacitated RSCs' locations is a combinatorial optimization problem and is a zero-one mixed integer programming with NP-hard complexity, we provide a heuristic algorithm named as incremental cost matrix procedure (ICMP) to simplify the solving procedure. By using the concise and structural cost matrix, ICMP can efficiently screen the potential location with cost advantage and effectively decide which distributor should be a RSC. Results obtained from the numerical experiments conducted in small scale problem have shown the fact that ICMP is an effective and efficient heuristic algorithm for solving the RSCs locating problem. In the future, using the extended ICMP to solve problems with larger industrial scale or problems with congestion effects caused by the variation of customer demand and the restriction of the RSC capacity is worth a further investigation.

• Journal of Korean Society of Transportation
• /
• v.24 no.7 s.93
• /
• pp.139-148
• /
• 2006

In order to incorporate substitution effects between different transport modes in optimal road Pricing, relating economic theories and models have been reviewed. It includes unconstrained optimization problem of maximizing separable and non-separable social net benefit functions of different substitutable urban transport modes. In doing that, the problem and limitations such as path-independent conditions with the asymmetric Jacobian of the objective function have been reviewed. Consequently, a plausible way of deriving optimal road price under interdependent market conditions has been suggested so that the idea can help identifying desirable and acceptable urban transport policy alternatives in a more comprehensive way.

• Proceedings of the KSR Conference
• /
• 1999.05a
• /
• pp.41-51
• /
• 1999

Trade between Korea and China was 372million dollars accounting for 1.56% of total in 1988 and has been increased to 23,689 million dollars occupying 7% in 1997, which implies 32.2% increase on average per year. This trend will continue dramatically and consistently as China's open policy toward the world accelerates and korean companies advance into chinese market. The main trade routes are with marine transportation between korean west sea area and chinese San-Dong peninsula around east sea. However, due to the increasing traffic congestion on main roads connecting harbors and main consumer cities and capacity problem in west sea harbor areas, the logistics cost have been increased resulting in losing competitiveness of freight trade. Therefore, these road-oriented inland transportation means need to be changed to rail transport system to reduce congestion and to conserve natural environment. To achieve this scheme, efficient intermodal transportation system connecting road and rail should be constructed. These combined system will ensure timely delivery of goods and consequently the customers would make proper transportation schedule for the import/export goods in advance. Especially, combined transportation of Railroad and train ferry would cope with the logistics problem and this system would be efficient means for trade with not only China but further with many adjacent countries in central asia such as Kazakhstan and Uzbekistan

• IEMEK Journal of Embedded Systems and Applications
• /
• v.13 no.2
• /
• pp.65-71
• /
• 2018

In order to make the underwater vehicle carry out the mission in a submarine environment, it is needed to plan a safe and efficient route to a given destination and prevent the autonomous submersible from colliding with obstacles while moving along the planned route. The function of collision avoidance makes the travel distance of the autonomous submersible longer. Moreover, it should move slowly near to obstacles against their moving disturbance. As a result, this invokes the degradation of the navigation efficiency in the process of collision avoidance. The side effect of the collision avoidance is not ignorable in the case of high congested environments such as the coast with many obstacles. In this paper, we suggest a path planning method which provides the route with minimum travel time considering collision avoidance in congested environment. For the purpose, we define environmental congestion map related to geometric information and obstacles. And we propose a method to consider the moving cost in the RRT scheme that provides the existing minimum distance path. We verified that the efficiency of our algorithm with simulation experiments.

• Proceedings of the IEEK Conference
• /
• 2002.07c
• /
• pp.1685-1688
• /
• 2002

Application Routing Load Balancing (ARLB) is a novel load balancing mode that combines QoS routing and load balancing in per application to support QoS far real-time application based on wired network. Zone Routing Protocol (ZRP) is a recent hybrid proactive/reactive routing approach in an attempt to achieve scalability of ad-hoc network. This routing approach has the potential to be efficient in the generation of control traffic than traditional routing schemes. Up to now, without proper load balancing tools, the ZRP can actually guarantee QoS for delay-sensitive applications when congestion occurred in ad-hoc network. In this paper, we propose the ARLB to improve QoS fur delay-sensitive applications based on ZRP in ad-hoc network when congestion occurred and to be forwarding mechanism fur route coupling to support QoS for real-time applications. The critical point is that the routing metric of ARLB is originally designed for wired network environment. Therefore, we study and present an appropriate metric or cost computation routing of ARLB for recently proposed ZRP over ad-hoc network environment.

• Journal of information and communication convergence engineering
• /
• v.11 no.1
• /
• pp.30-44
• /
• 2013

Traffic congestion has become a serious problem with the recent exponential increase in the number of vehicles. In urban areas, almost all traffic congestion occurs at intersections. One of the ways to solve this problem is road expansion, but it is difficult to realize in urban areas because of the high cost and long construction period. In such cases, traffic signal control is a reasonable method for reducing traffic jams. In an actual situation, the traffic flow changes randomly and its randomness makes the control of traffic signals difficult. A prediction of traffic jams is, therefore, necessary and effective for reducing traffic jams. In addition, an autonomous distributed (stand-alone) point control of each traffic light individually is better than the wide and/or line control of traffic lights from the perspective of real-time control. This paper describes a stochastic optimum control of crossroads and multi-way traffic signals. First, a stochastic model of traffic flows and traffic jams is constructed by using a Bayesian network. Secondly, the probabilistic distributions of the traffic flows are estimated by using a cellular automaton, and then the probabilistic distributions of traffic jams are predicted. Thirdly, optimum traffic signals of crossroads and multi-way intersection are searched by using a modified particle swarm optimization algorithm to realize real-time traffic control. Finally, simulations are carried out to confirm the effectiveness of the real-time stochastic optimum control of traffic signals.

• Journal of Information Processing Systems
• /
• v.15 no.4
• /
• pp.833-852
• /
• 2019

In real time applications, due to their effective cost and small size, wireless networks play an important role in receiving particular data and transmitting it to a base station for analysis, a process that can be easily deployed. Due to various internal and external factors, networks can change dynamically, which impacts the localisation of nodes, delays, routing mechanisms, geographical coverage, cross-layer design, the quality of links, fault detection, and quality of service, among others. Conventional methods were programmed, for static networks which made it difficult for networks to respond dynamically. Here, machine learning strategies can be applied for dynamic networks effecting self-learning and developing tools to react quickly and efficiently, with less human intervention and reprogramming. In this paper, we present a wireless networks survey based on different machine learning algorithms and network lifetime parameters, and include the advantages and drawbacks of such a system. Furthermore, we present learning algorithms and techniques for congestion, synchronisation, energy harvesting, and for scheduling mobile sinks. Finally, we present a statistical evaluation of the survey, the motive for choosing specific techniques to deal with wireless network problems, and a brief discussion on the challenges inherent in this area of research.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.5
• /
• pp.159-169
• /
• 2008

The aim of this paper is to research the changes of social welfare by internalizing external cost, especially the maintenance cost. Main target of this paper is the Cheonan$\sim$Nonsan Line, where private capital highway, national highway and local road are competing against each other. Considering the realistic difficulties in applying the First Best pricing, this paper applied the Second Best pricing, applying the maintenance cost, in lieu of the already mentioned. The demand functions of the toll roads were built through regression analysis. By reflecting the maintenance cost to the toll fee, It was able to confirm the variation of social welfare deriving from the traffic assign change but also the aspects of toll revenue at the same time. Result of applying the Second Best pricing shows merely a small change in social welfare. However, in the aspect of finance, it is analyzed that there will be about 13 billion won worth of financial effectiveness which will contribute to the reduction of the national financial support.

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

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2016.05a
• /
• pp.207-208
• /
• 2016

By according to increase the research for autonomous vehicle in automobile industries, the efficient of autonomous cargo truck instead of conventional driver cargo truck will be analyzed in logistics areas. The inland transportation has been serious problem such as traffic accident, traffic congestion in downtown, air pollution, noise and etc. even if it have a great effect to logistics industries. Especially there have to be improved its transportation schedule and sleepy driving in night which induced heavy accident in highway. In this study, the effectiveness of autonomous cargo truck will be analysed by considering the logistics cost including social effects.