• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.447-455
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• 2005

Intra-block remarshalling is the task of rearranging into some target bays those containers which are scattered within around the block. If multiple transfer cranes installed in the block are all used together we may be able to complete the remarshalling task as early as possible. However, when multiple cranes are used simultaneously, there may occur significant delays if we do not carefully consider interferences between the cranes at the time of scheduling. Especially, delays caused by interferences occur more frequently in case of using non-crossing cranes. This paper presents an efficient heuristic method for assigning moves of containers to each crane and for determining an appropriate container moving order in a manner sensitive to the interferences. Simulation experiments have shown that the proposed method can effectively reduce delays in various environments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.243-248
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• 2006

Recently, China opened Yangshan port and provides a variety of benefits for shipping companies. Japan plans to reduce logistics costs and improve efficiency through the established 'super major ports' project. According to the 'hub and spokes' system, the number of direct calls toward North-Chinese ports are increasing. This changing environment has negative effects on the amount of transshipment cargos in Korean ports. In order to make a hub port of a domestic port, it is necessary to develop northeast Asian Feeder networks. Therefore, this paper analyzes the structure of northeast Asian feeder networks through the case study of European feeder networks strategy. Finally, we suggests the plans to reinforce feeder networks, which are strategic terminal operation, strategic alliances between shipping companies and port co-operation, for win-win strategy in the competitive northeast Asian market.

• Journal of Navigation and Port Research
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• v.40 no.3
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• pp.113-120
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• 2016

If there are containers stacked upon the container to be fetched out of a container yard to vessel, rehandling which moves those containers to other places temporarily is needed. In order to avoid such rehandling, remarshalling which rearranges containers should be done before the vessel arrives. The remarshalling plan is commonly generated within a bay. It happens, however, that the generation of the intra-bay remarshalling plan within the permitted time is not possible because of bad stacking conditions. This paper presents the remarshalling algorithm which uses the empty slots of the neighboring bay as a temporary storage space. Simulation experiments have shown that the presented algorithm can generate the remarshalling plan within the permitted time under any staking conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.210-211
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• 2009

The container has the inherent number which for distinguish among containers. When containers were handled, the container No. identify work must be precede. The work goes by fond in Most of the ports. It has not only inefficient time and cost but also error as worker's condition. The measure is operated that to use the camera on the spreader of quay crone to solve that problem. This measure, however, showed up the difference q recognition rates at weather, camera's condition, etc The ways could be considered both improvement of hardware and conversion of error number to solve the measure. This paper defines the problem and study an efficient solution.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.409-414
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• 2017

In point of fact, there is a lack of explicit models that explain how services are perceived and evaluated by consumers who use them; present research on service quality has begun as a measure to complement this development. In this study, we applied the service quality model of PZB model based on Parasuraman et al.(1988) and the BNC model based on Brady and Cronin(2001), and compared the superiorities of each model. As a result of analyzing the questionnaire provided for terminal users, the BNC model is more superior than the PZB model. The increase in the number of factors led to an increase in the provided information, as a result of this, the model's explanatory power seems to be high. The results of this study may be different according to the characteristics of the industry, but we hope that the results presented in this study will lead to the expansion of the scope of research for the port loading and unloading business in the future.

• Journal of KIISE:Software and Applications
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• v.33 no.7
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• pp.624-635
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• 2006

This paper applies simulated annealing algorithm to the problem of generating a plan for intra-block remarshalling with multiple transfer cranes. Intra-block remarshalling refers to the task of rearranging containers scattered around within a block into certain designated target areas of the block so that they can be efficiently loaded onto a ship. In generating a remarshalling plan, the predetermined container loading sequence should be considered carefully to avoid re-handlings that may delay the loading operations. In addition, the required time for the remarshalling operation itself should be minimized. A candidate solution in our search space specifies target locations of the containers to be rearranged. A candidate solution is evaluated by deriving a container moving plan and estimating the time needed to execute the plan using two cranes with minimum interference. Simulation experiments have shown that our method can generate efficient remarshalling plans in various situations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2834-2851
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• 1997

In this paper, a design and implementation of VHDL compiler front-end, aims at supporting the full-set of VHDL '87 & '93 LRM and carring out the preprocessing of VHDL-to-C, is described. The VHDL compiler front-end includes 1)the symbol tree of analyzed data to represent the hierarchy, the scope and visibility, the overloading and homograph, the concurrent multiple stacks in VHDL, 2)the data structure and supportig routies to deal with the objects, the type and subtype, the attribute and operation in VHDL, 3)the analysis of the concurrent/sequential statements, the behavior/structural descriptions, of semantic token and the propagation of symbol & type to improve the registration and retrieval procedure of analyzed data. In the experiments with Validation Suite, the VHDL compiler front-end could support the full-set specification of VHDL LRM '87 & '93; and in the experiments to asses the performance of symantic token for the VHDL hierachy/visibility/concurrency/semantic checking, the improvement of about 20-30% could be achieved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1222-1229
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• 2012

For the reduction of electric energy consumption and its efficient use at homes or buildings, a new work item proposal for new architecture and functional requirements of Energy Saving System (ESS) was proposed to IEC TC 100 and accepted as a new project, IEC PT 62654 in 2009. Recently, the final ballot for publication passed without negative votes and IEC TS 62654 was finally published in August 2012. For the verification of this standard, Prototype of ESS system composed of an ESS server, ESS clients, and portable ESS terminal were especially implemented in parallel with the standardization. Electric Power Control and Management (EPCM) protocol for the communication between ESS server and clients was also implemented, which supports self-configuration of ESS network, power consumption monitoring, remote power control, and additional functions for intelligent energy saving services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2A
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• pp.132-138
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• 2009

Cognitive radio is considered as a promising solution to scarce spectrum problem. The primary object of cognitive radio is to increase spectral efficiency, while causing limited interference to primary users who are using the spectrum. Hence, an essential part of cognitive radio systems is spectrum sensing which determines whether a particular spectrum is occupied or not by a primary user at a particular time. However, sensing decision of each individual secondary user alone may not be reliable enough due to shadowing and multipath fading of wireless channels. The so called hidden terminal problem makes the problem even worse, possibly yielding undesired interference to the primary users. Recently, cooperative spectrum sensing is emerging as a remedy to these problems of individual sensing. Cooperative sensing allows a group of secondary users to share local sensing information to extract a global decision with high fidelity. In this paper, we investigate a cooperative spectrum sensing algorithm based on hard decisions of local sensing outcomes. Specifically, we propose an effective scheme for combining local decisions by introducing weighting factors that reflect reliability of the corresponding secondary user. Through computer simulations, the performance of the proposed combining scheme is compared with that of the conventional scheme without weighting factors in various environments.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.3
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• pp.277-288
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• 2002

In this paper, we describe a design and implementation method of a smart card operating system for multi applications. A smart card is the independent computing system and is able to be used in multi applications such as the electronic commerce and the electronic cash. Smart card operation system(SCOS) provides a basis of smart card booting, and controls and manages application programs. SCOS can produce and control a file system to support multi applications in EEPROM, communicate commands and messages with outside devices, process a command, produce a reply message, and provide security functions of file security in EEPROM, and communication security. Therefor, in this paper, we design and implement SCOS system that provides the authentication between a card and a terminal, the session authentication for multi applications, the processing of commands, and the maintenance of the security.