• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.157-160
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• 2000

In this paper, the development of a new group controller for high-speed elevator is carried out utilizing approach of an adaptive dual fuzzy logic. A goals of control are the minimization of waiting time, mean-waiting time and long-waiting time in a high building, when a new hall call is generated, adaptive dual fuzzy controller evaluate traffic pattern and change appropriately the membership function of fuzzy rule, base. Control for co-operation among elevators in group control algorithm are essential , and the most critical control function in group controller is a effective and proper hall call assignment of elevators. The group elevator system utilizing adaptive dual fuzzy control reveals a great deal of improvement on its performance.

• Journal of Communications and Networks
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• 제10권2호
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• pp.127-136
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• 2008

For mobile wireless systems with full frequency reuse, co-channel interference near the cell coverage boundaries has a significant impact on the signal reception performance. This paper addresses an approach to efficiently mitigate the effect of downlink co-channel interference when multi-antenna terminals are used in cellular environments, by proposing a signal detection strategy combined with a system-level coordination for dynamic frequency reuse. We demonstrate the utilization of multi-antennas to perform spatial demultiplexing of both the desired signal and interfering signals from adjacent cells results in significant improvement of spectral efficiency compared to the maximal ratio combining (MRC) performance, especially when an appropriate frequency reuse based on the traffic loading condition is coordinated among cells. Both analytic expressions for the capacity and experimental results using the adaptive modulation and coding (AMC) are used to confirm the performance gain. The robustness of the proposed scheme against varying operational conditions such as the channel estimation error and shadowing effects are also verified by simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.439-442
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• 2002

If can be operated on virtually any network transmission media and used to communicate each other whatever system platforms are. But, with the enormous growth of the Internet in the past a few years, the amount of network traffic has increased as the number of users and applications has increased. New applications have new service demands for fulfilling user's satisfaction, and as a result the Internet needs to change as well. This paper shows that why the Internet must change to satisfy the need for QoS to accommodate these and performance of network using QoS establishing 5 Scheme has a dominant improvement through a simulator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.481-484
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• 2002

In recent, the contactless IC card is widely used in traffic, access control system and so forth. And its use becomes a general tendency more and more because of the development of RF technology and improvement of requirement for user convenience. This paper describes the hardware module to process contactless protocol for implementation contactless IC card. And the hardware module consists of specific digital logic circuits that analyze digital signal from analog circuit and then generate data & status signal for CPU, and that convert the data from CPU into digital signal for analog circuit.

• 에너지공학
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• 제2권1호
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• pp.22-27
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• 1993

수송용 에너지 수요변화에 대한 요인분석을 시도하고자 에너지 수요함수를 추정하고, 이에 따라 수요변화에 대한 각 요인별 기여도를 산출하였다. 여기서, 에너지 수요를 결정하는 요인으로 가격, 경기, 수송활동 및 연료전환 등의 변수를 채 택하였다. 기여도 분석 결과 나타난 시사점을 몇 가지로 요약할 수 있다. 1) 가격요인의 기여도는 최근의 경우보다 증대되고 경기요인의 기여도는 현재 수준보다 작아지는 것이 바람직하다. 2) 수송활동 요인의 ＋효과가 증대되는 시점에서 연료경제 향상 및 에너지절약적 교통체계 개선노력이 중요시되고 있다. 3) 연료전환요인의 휘발유로의 ＋효과가 커지고 있기 때문에 에너지 이용효율이 높은 대중 교통수단의 이용을 증대시키기 위한 정책적 노력이 지속되어야 할 것이다.

• Journal of Communications and Networks
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• 제12권1호
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• pp.30-42
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• 2010

In this work we consider the problem of downlink resource allocation for proportional fairness of long term received rates of data users and quality of service for real time sessions in an OFDMA-based wireless system. The base station allocates available power and subchannels to individual users based on long term average received rates, quality of service (QoS) based rate constraints and channel conditions. We formulate and solve a joint bandwidth and power optimization problem, solving which provides a performance improvement with respect to existing resource allocation algorithms. We propose schemes for flat as well as frequency selective fading cases. Numerical evaluation results show that the proposed method provides better QoS to voice and video sessions while providing more and fair rates to data users in comparison with existing schemes.

• 산업경영시스템학회지
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• 제35권4호
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• pp.171-178
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• 2012

A possible heuristic to solve metropolitan area vehicle routing problems with variable vehicle speeds is suggested in this research. Delivery hours are classified into 4 different time zones to make variable vehicle speeds no change within the same time zone to make TDVRP simple to solve. The suggested heuristic consists of 2 stages such as initial solution development step and initial solution improvement step. A computer program using C++ is constructed to evaluate the suggested heuristic. Randomly generated vehicle routing problems are used for the experiments. This heuristic could be helpful to logistics companies by increasing delivery efficiencies since the 4 zone classification is taken from the observed traffic information offered by a local government.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2413-2425
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• 2008

Until now, Many papers were written by graduate school students and consultents about railway station as main consideration. But there is no paper about specific private-invested station development. So in this paper, Just consider limiting Dong-Incheon private-invested station on a noncompetitive point of view that also constructed as a part of railway station development. This paper will be referenced of private-invested station management and direction of development in Korail railway station development. Private-invested station development is actively drived to now after Seoul private-invested station in 1989 as Korail's first induced private capital. Dong-Incheon private-invested station also built in 1989 and operated to now, but it can't keep up with current market and can't meet changeable commercial business. So in this paper, comparing Dong-Incheon private-invested station with one of the successful private-invested stations which is youngdengpo private-invested station and seeking the improvement direction of Dong-Incheon private-invested station as considering Dong-Incheon private-invested station's floating, traffic system, walking line, the range of station, the development type, facilities, and other nation's developing cases.

• 대한안전경영과학회지
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• 제13권2호
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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.

• International Journal of Railway
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• 제2권2호
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• pp.50-59
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• 2009

Numerous train operating companies provide training by means of driving simulators. A detailed analysis in the course of the rail research project 2TRAIN has shown that the simulation technology, the purposes of training and the overall concept of simulator-based training are rather diverse (Schmitz & Maag, 2008). A joint factor however are weak assessment capabilities and the fact that the simulator training is often not embedded into the overall competence management. This fact hinders an optimal use of the simulators. Therefore, 2TRAIN aims at the development of enhanced training and assessment tools. Taking into account that several simulators are already in use, the focus lays on the extension of existing simulation technology instead of developing entirely new systems. This extension comprises (1) a common data simulation interface (CDSI), (2) a rule-based expert system (ExSys), (3) a virtual instructor (VI), and (4) an _assessment database (AssDB). The foundation of this technical development is an assessment concept (PERMA concept) that is based on performance markers. The first part of the paper presents this assessment concept and a process model for the two major steps of driver performance assessment, i.e. (1) the specification of exercise and assessment and (2) the assessment algorithm and execution of the assessment. The second part describes the rationale and the functionalities of the simulator add-on tools. Finally, recommendations for further technical improvement and appropriate usage are given. based on the results of a pilot study.