• 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.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2625-2634
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• 2022

Discretization errors are extremely challenging conundrums of discrete ordinates calculations for radiation transport problems with void regions. In previous work, we have presented a multi-collision source method (MCS) to overcome discretization errors, but the efficiency needs to be improved. This paper proposes a goal-oriented algorithm for the MCS method to adaptively determine the partitioning of the geometry and dynamically change the angular quadrature in remaining iterations. The importance factor based on the adjoint transport calculation obtains the response function to get a problem-dependent, goal-oriented spatial decomposition. The difference in the scalar fluxes from one high-order quadrature set to a lower one provides the error estimation as a driving force behind the dynamic quadrature. The goal-oriented algorithm allows optimizing by using ray-tracing technology or high-order quadrature sets in the first few iterations and arranging the integration order of the remaining iterations from high to low. The algorithm has been implemented in the 3D transport code ARES and was tested on the Kobayashi benchmarks. The numerical results show a reduction in computation time on these problems for the same desired level of accuracy as compared to the standard ARES code, and it has clear advantages over the traditional MCS method in solving radiation transport problems with reflective boundary conditions.

• Journal for History of Mathematics
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• v.28 no.2
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• pp.103-115
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• 2015

Contemporary differential geometry owes much to the theory of connections on the bundles over manifolds. In this paper, following the work of Gauss on surfaces in 3 dimensional space and the work of Riemann on the curvature tensors on general n dimensional Riemannian manifolds, we will investigate how differential geometry had been developed from mid 19th century to early 20th century through lives and mathematical works of Christoffel, Ricci-Curbastro and Levi-Civita. Christoffel coined the Christoffel symbol and Ricci used the Christoffel symbol to define the notion of covariant derivative. Levi-Civita completed the theory of absolute differential calculus with Ricci and discovered geometric meaning of covariant derivative as parallel transport.

• Journal of the Korean Graphic Arts Communication Society
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• v.11 no.1
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• pp.103-122
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• 1993

A cause and counterplan of the increase in dark decay rate of$\varepsilon$-CuPc/PVCz photoreceptor which is consist of the carrier generation layer (CGL) of$\varepsilon$type copper phthalocyanine ($\varepsilon$-CuPc) thin film by an aqueous coating method and the carrier transport layer (CTL) of polyvinylcarbazol (PVCz) by spin coating, are studied in this paper. Electrochemical deposition of CGL was accompanied by an increase in work function of the aluminium substrate during the processes and the enhanced work function 5.3 eV rose above the ionization potential 5.16 eV of $\varepsilon$-CuPc. This resulted in the increased injection of holes from substrate into CGL and a fast dark decay rate. Improved photoreceptor, an electron-transport $\varepsilon$-CuPc/TNF photoreceptor, led to lowing of dark decay rate and increasing of photosensitivity. The carrier generation efficiency (ηg), carrier injection efficiency (ηi) and xerographic gain (G) of the $\varepsilon$-CuPc/TNF photoreceptor were obtained by XTOF method and PIDC.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.31-37
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• 2011

Construction automation is yet to be improved since construction site still faces a lot of high risks and difficulties. This research focuses on applying robotic beam assembly system in place of construction workers. This system consists of CF (Construction Factory) structure to provide adequate working environment to robot automation. The CF structure not only gives automation environment for a robot but also houses the equipments to protect from outside effects. The robotic beam assembly system also consists of robotic bolting system and robot transport mechanism. It utilizes various tools to insert and join the bolts and nuts. Visual servoing helps precise robot motion by sensing bolt hole and tail of the bolt. ITA system helps non skilled workers to easily perform the assembly work with the robot system. The robot transport mechanism includes sliding rail and cross-wired lift. It carries the robot to a desired position for assembly work.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.29-33
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• 1998

Transport phenomena paly an inmportant role in bulk crystal growth processes. During crystal growth, the control of the growth front and the dopant concentration is crucial to crystal quality. The growth feasibility in thus determined by the heat transfer controlling the interface convexity and by the mass transfer controlling the constitutional supercooling. Through numerical modeling, a thorough understanding of the growth processes is possible, which in turn is a key to process improvenment. In this paper, we will summarize some work dine in my laboratory, both numerical and experimental, to illustrate the importance of understanding the transport phenomena during crystal growth processes.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.157-158
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• 2018

In this work, we developed a customized shielded cask transport system which is equipped with a railguided travelling unit and a position adjustment unit for the cask without any crane service. The designed solid model was verified to have sufficient safety margin by using structural analysis. The developed system was introduced to a hot-cell and successfully tested and verified to have required target performance.

• Journal of Distribution Science
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• v.12 no.2
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• pp.27-37
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• 2014

Purpose - As economic activities between different countries have rapidly spread in a world of free trade, it is inevitable that a large volume of cargo will be carried between countries. It is natural, then, that CO2 emissions and other environmental pollutions have followed, which exposes people and society to serious environmental problems and social costs, and so on. Therefore, the need to understand logistics is not only a matter of transportation but also an environmentally oriented matter. The purpose of this study is to look at some lessons and implications from the European case in terms of green logistics matters. Research design, data, and methodology - In order to look into this matter, first, it has to be established that some cargo transport volumes using different transportation modes have clearly declined because of previous economic recessions. Some transport policies produced by the European Union (EU) are based in a long history of struggling to cope with transport matters in European countries. In its recent transport policies, the EU has provided greener transportation alternatives, realizing that pollution matters affect the European transport market. This study tries to determine what policies the EU has implemented to deal with green logistics matters. This study concentrates in particular on the Marco Polo program in the EU. Results - This study found that the EU seems to consider these kinds of matters, that is, transport and the environment in the context of green logistics. The EU launched some policy instruments to solve this matter relatively earlier than other countries and reviewed them as necessary. In order to make these policy tools work, the EU provided PACT for combined transport, and then the Marco Polo I and II European transport white paper packages. These European policies deal with green logistics matters in two ways. First, some restrictions have been imposed, especially taxation, and so on. Transport subsidies are also powerful means of handling green logistics matters in Europe. Along with these two means of dealing with transport and the environment, the EU eventually targeted integration of different transport modes. Instead of employing only a single transport instrument mode to deliver the cargo to be carried, such as trucking, rail, ocean-going carrier, flight, or inland waterway transport, the EU has proposed that combining transport modes is the best alternative for transport and the environment. That is, the EU is pursuing the adoption of multimodalism as an answer to the green logistics challenge as it provides a more cost efficient and more productive means of transport. Conclusions - In conclusion, multimodal transport should be considered when applying green logistics, as it can provide an alternative way to achieve transport and environmental solutions together at the present time. Two methods can be used to encourage multimodal transport: restrictions and subsidies. These are the lessons and implications from European green logistics policies.

• Journal of Korean Society of Transportation
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• v.30 no.4
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• pp.61-70
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• 2012

This research explores different non-work trip characteristics between the elderly group (65+) and the working age group (20-64) using heteroscadastic ordered logit model. The analysis is based on travel survey data of Seoul Metropolitan area in 2006. The results show that age induces heteroscadasticity and the model provides a better fit than ordered logit model. The factors increasing the number of non-work trip of the elderly were driver's license and household income. Conversely, the number of non-work trips decreased in those groups that were male, with a job, in aging, and with the number of preschool children. The factors having opposite effects (increased the number of non-work trips in the working age groups and decreased in the elderly group) between the elderly group and working age group were age and job.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.23-35
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• 2017

Work zone traffic control is of keen interest because both traffic operations and safety performances are directly affected by traffic management methods. In particular, work zone traffic on two-lane roads needs to be managed in more efficient and safer manners due to its unique characteristics of alternative right-of-way assignment. This study developed a dynamic control algorithm that can be used for real-time operations of two-lane work zone traffic. The performance of the developed algorithm was evaluated by VISSIM microscopic traffic simulator. An applied programming interface (API) based program was developed to plug-in the control algorithm onto the simulator. The results demonstrated the feasibility of the proposed control algorithm for two-lane work zone.