• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1590-1593
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• 2002

We propose a dynamic location management scheme and named it Virtual Dynamic Location Area(VDLA) scheme. It allocates LA on the basis of terminal mobility, VDLA consists of two phases: VLA allocation and final LA selection phases. In the first phase it allocates primary and secondary VLAs to the terminal. In the second phase the terminal selects one of them using LA selection criterion. Cost analysis of the proposed scheme is peformed and its location management cost is compared with those of FLA and DBLA.

• 유통과학연구
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• 제15권12호
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• pp.53-60
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• 2017

Purpose - This paper analyzes the effect of the handset subsidy and the Mobile Number Portability subscriber subsidy regulation, which are the main regulation adopted in "Law on the Improvement of the Mobile Terminal Distribution System" (Mobile Terminal Distribution Act), on the social surplus, the consumer surplus and profits of telecommunications carriers. We focus our analysis on whether the service charge competition is stimulated enough so that it can compensate for the loss of subsidies. Research design, data, and methodology - We use simple economic model to assess the impact of the handset subsidy and the Mobile Number Portability subscriber subsidy regulation. Unlike the former researches on this topic, we depart from using Hotelling model, and instead use the switching cost model, which uses switching cost as a parameter of market powers of telecommunications carriers. We also study the effect of the two different regulations when they are adopted both independently and concurrently. Results - If the market powers of telecommunications carriers are over certain threshold, contrary to the regulatory agency's assertion, the service charge competition would not be stimulated enough to compensate for the deduction in the subsidies, and thus the consumer surplus is compromised. Number Portability subsidy, especially, undermines the rival's market power and thus reduces the service charge. On the other hand, the regulations will also increase the profits of telecommunications carriers. However, social surplus is maximized when both of the regulations are present because the regulations reduces the frequency of switching handsets inefficiently. Conclusions - In enacting the Mobile Terminal Distribution Act, the telecommunications regulatory agency asserted that the regulation on subsidies will stimulate service charge competition, and in the long run, enhance the consumer surplus. However, contrary to the regulatory agency's assertion, subsidy regulation, especially the regulation on Number Portability subsidy, reduces consumer surplus. On the other hand, the Mobile Terminal Distribution Act can also increase the profits of telecommunications carriers because it decreases competition among the telecommunications carriers. However, the Mobile Terminal Distribution Act can increase the social surplus because it reduces inefficient switching of handsets.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.27.2-27
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• 2001

This paper proposes a receding horizon predictive control (RHPC) for nonlinear time-delay systems. The control law is obtained by minimizing finite horizon cost with a terminal weighting functional. An inequality condition on the terminal weighting functional is presented, under which the closed-loop stability of RHPC is guaranteed, A special class of nonlinear time-delay systems is introduced and a systematic method to find a terminal weighting functional satisfying the proposed inequality condition is given for these systems. Through a simulation example, it is demonstrated that the proposed RHPC has the guaranteed closed-loop stability for nonlinear time-delay systems.

• ETRI Journal
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• 제34권6호
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• pp.838-846
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• 2012

This paper proposes a cost-effective hybrid-type power budget extender (PBEx) that can provide a high power budget of over 45 dB in an asymmetric 10-Gb/s Ethernet passive optical network (10/1G-EPON). The hybrid-type 10/1G-EPON PBEx comprises a central office terminal (COT) and remote terminal (RT) module supporting four channels and uses a coarse wavelength division multiplexing (CWDM) technology between the COT and RT for a reduction of fiber cost and efficient access network design. The proposed 10/1G-EPON PBEx can provide over a 40-km reach and 128-way split per CWDM wavelength with no modification of a legacy 10/1G-EPON system and can satisfy the error-free service in $10^{10}$ packet transmission.

• 한국경영과학회지
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• 제33권2호
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• pp.75-86
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• 2008

A remarshalling is one of the operational strategies considered importantly at a port container terminal for the fast ship operations and heighten efficiency of slacking yard. The remarshalling rearranges the containers scattered at a yard block in order to reduce the transfer time and the rehandling time of container handling equipments. This Paper deals with the rearrangement problem, which decides to where containers are transported considering time value of each operations. We propose the mixed integer programming model minimizing the weighted total operation cost. This model is a NP-hard problem. Therefore we develope the heuristic algorithm for rearrangement problem to real world adaption. We compare the heuristic algorithm with the optimum model in terms of the computation times and total cost. For the sensitivity analysis of configuration of storage and cost weight, a variety of scenarios are experimented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.65-70
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• 1999

In this paper, the cost-effective design of output reactor which is used to suppress the over-voltage at the motor terminal in the Adjustable Speed Drives(ASD) application is proposed. In the elevator drive system, the power cable length is relatively shorter than other ASD applications and then the over-voltage at the motor terminal depends on the frequency characteristics of the output reactor at the over-voltage operating frequency. The over-voltage suppression mechanism of output reactor in ASD application is analyzed and the dominant parameters of output reactor for the over-voltage suppression are extracted. Using these parameters as the design values and considering the high frequency characteristics of iron core in the reactor, a new cost-effective structure of output reactor is proposed. Experimental results of the conventional reactor and the proposed reactor with a 15kW induction motor are given to verify the proposed scheme.

• 한국항해항만학회지
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• 제45권5호
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• pp.238-251
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• 2021

It is understood that carriers evaluate several features of ports when fixing the T/S port. Those features can be enumerated as Geographic condition of port, Service network with overseas ports, Level of port productivity, Port infrastructure, Port services level, Port Authority's Policy direction mand Cost competitiveness. The objectives of this study are to: 1) determine if those factors could affect the T/S competitiveness of the port; and 2) to evaluate how Busan port conforms to those determinants factors in such extent. According to results of the analysis after surveying National global carrier, Intra-Asia carriers, Global overseas carriers, Terminal operators, and Busan Port Authority known to be highly influential samples, all factors were proven to be factors affecting the T/S competitiveness of the port. Meanwhile, in the analysis through AHP (Analytic Hierarchy Process) methodology about the order of weight among those factors, Cost competitiveness was answered as the most important factor. On the other hand, in the analysis to find the situation if Busan port conforms to those factors, Busan port was proven to satisfy those conditions to a moderate extent. In the analysis about the order of strength among those factors, Busan port was answered to have the highest strength in the geographic condition. However, it showed the bottom level of strength in the Cost competitiveness which was answered as the most important factor among samples for determining the T/S competitiveness of the port. This indicates that Government and Port Authority of Busan have to concentrate policy capabilities on the improvement of cost competitiveness of Busan port to enhance the T/S competitiveness. In this paper, four policy recommendations are given : Integration of Busan port operation into New port, Combining multiple operators into one or a few, Attracting Global mega carriers as the New port terminal operators, and Continuous Infrastructure expansion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.252-254
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• 2004

This paper proposes a common platform for an internet-based mobile robot and its operator terminal. The common platform can reduce the cost and time to develop an internet-based robot and its operator terminal. The robot performs the role of a server and its terminal a client. One operator can use this terminal to make a command and this command can be sent to the robot through a wireless network. According to given commands, the robot moves a point and sends an image by using a camera or desired information by using other sensors. The information sent from the robot can help an operator to control the robot. The mobile robot consists of two modules, main module and motion module. Main module can exchange information with the operator terminal, process information, and send a command to motion module. Each application program for one internet-based mobile robot and its operator terminal will be developed to show that the same platform can be used for them. Also, it will be shown that the robot can be controlled easily by using its operator terminal.

• 한국항해항만학회지
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• 제46권3호
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• pp.236-242
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• 2022

부산항은 다수 터미널 운영사에 의해 분리 운영되고 있어 ITT(Inter-Terminal Transportation) 물량이 다수 발생한다. ITT 물량발생은 추가 운송비용, 공차운송, 차량 대기 및 터미널 혼잡 등 다양한 문제를 초래해 부산항 경쟁력을 약화시키고 있다. 그 중 공차운송 문제는 부산항 ITT 운영에 있어서 비용 문제를 악화시키는 대표적인 요인이지만 부산항의 ITT 복화율은 낮은 수준에 머물고 있다. 부산항 환적 경쟁력 강화를 위해서는 ITT 복화율을 높일 수 있는 방안이 필요하다. 따라서 본 연구는 ITT의 복화율 개선을 위해 완충지역을 활용한 복화운송 최대화 수리모형을 제시하였다. 그리고 실제 운영 데이터에 기반한 실험을 통해 완충지역 활용에 따른 복화율 개선 효과를 분석하였다.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 2004년도 춘계학술대회
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• pp.122-137
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• 2004

Automation of a container terminal is a world-wide tendency nowadays. The interest of ACT (Automated Container Terminal) is increasing more and more because of necessity of container terminal with higher competitive power and ultramodern equipment to down the cost and up the efficiency. ECT (Europe Combined Terminals) and CTA (Container Terminal Altenwerder) have studied a detailed technique for the operation of ACT. In Korea, many projects related to the development of ACT are working at present. However, indiscreet introduction of ACT may cause tremendous loss. Thus it is much important thing that we search relevant automation level or type for an environment In this study, we propose the necessary strategy in developing ACT through analyzing the present condition, automated equipments and property of operation at advanced An. If the strategy is applied in development of domestic ACT, we'll be able to build ACT with higher competitive power.