• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.709-710
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• 2008

무선 시스템에서는 수신도 송신처럼 에너지를 소모한다. 이러한 전력소모는 배터리를 전원으로 오랜시간 동작해야하는 센서 망에서는 치명적이다. 특히 센서 네트워크를 위해 제안된 경쟁기반 방식의 MAC은 에너지 소모를 야기하는 패킷간의 충돌을 최소화 하고 전송지연 을 줄이는 프로토콜이 필요하다. 본 논문에서는 adaptive S-MAC의 방식을 그대로 사용하면서 간섭에 의한 충돌을 줄이는 알고리즘을 이용하여 한 SYNC interval 내에서 최대 3홉까지 전송 가능한 MAC 프로토콜을 제안하였다. NS2의 시뮬레이션을 통해 제안한 MAC 프로토콜의 성능을 기존 MAC과 비교하여 증명하였다.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.967-970
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• 2003

A new adder-and-accumulator (A$^2$C) adapted to pipelined Δ$\Sigma$ modulators is proposed in this paper. With the viewpoint of area consumption, registers are removed in the existing pipelined Δ$\Sigma$ modulator, and then adder and accumulator are merged. In order to optimize area consumption, speed and power consumption, dynamic carry look-ahead adder (CLA) is adopted in $A^2$C. Moreover, a guideline for the transistor sizing in CLA with regard to the minimization of the energy-delay-area product (EDAP) is proposed[1]. The proposed $A^2$C has been verified by HSPICE simulations.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.12a
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• pp.97-101
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• 1996

Municipal and sanitary landfills can pose environmental problems due to leachate, landfill gas md unstable geotechnical properties. Most governmental bodies delay the correction of landfill problems or landfill replacement until a crises stage is reached. The replacement of a landfill is often made difficult due to costly regulatory controls, public opposition to siting and the high cost of closure for the previous landfill unit. Solutions to extending landfill life and capacity Involve waste minimization by recycling, refuse compaction and waste-to-energy incineration. Incineration can reduce the volume of refuse by 50-95%. The largest installed bases of municipal waste Incinerators are located in Japan and the U.S. The volume of waste contained in a landfill can be estimated by load count tabulations, weight-and-volume measurements or a material balance analysis based on the trash profile of user categories. for an existing landfill, core samples may be collected and analyzed for use in a material balance analysis. Newly generated refuse contains approximately 50% of the heating value of coal. However, landfill properties vary significantly due to the waste profile of the contributors and biodegradation due to time and weathering. The volume of the Nanji-do landfill

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.8
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• pp.798-803
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• 2007

In case of minimized digital camera and mobile digital camera, it's difficult to get the high quality image by conventional AE(Auto Exposure) algorithm because of restriction of system organization. In this paper, a new algorithm that adopts a target setting, a compensation of feedback delay and a gamma correction, etc, are suggested for improving a noise increase and an output sensitivity decrease due to system minimization. We also suggest a method using fuzzy logic which can decide more effectively the ES(Electric Shutter) value and the AGC(Analog Gain Control) value than conventional system.

• Management Science and Financial Engineering
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• v.16 no.1
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• pp.59-79
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• 2010

This paper considers bandwidth allocation and scheduling problems on Ethernet Passive Optical Networks (EPON). EPON is one of the good candidates for the optical access network. This paper formulates the bandwidth allocation problem as a nonlinear mathematical one and characterizes the optimal bandwidth allocation which maximizes weighted sum of throughput and fairness. Based upon the characterization, two heuristic algorithms are suggested with various numerical tests. The test results show that our algorithms can be used for efficient bandwidth allocation on the EPON. This paper also shows that the WSPT (Weighted Shortest Processing Time) rule is optimal for minimization the total delay time in transmitting the traffic of the given allocated bandwidth.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.1
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• pp.59-64
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• 2020

Scheduling of electric vehicles and optimizing for charging waiting time have been critical. Meanwhile, it is challengeable to exploit the fluctuating data from electric vehicles in real-time. We introduce an optimal routing algorithm and a simulator with electric vehicles obeying the Poisson distribution of the observed information about time, space and energy-demand. Electric vehicle routing is updated in every cycle even it is already set. Also, we suggest an electric vehicle routing algorithm for minimizing total trip time, considering a threshold of the waiting time. Total trip time and charging waiting time are decreased 34.3% and 86.4% respectively, compared to the previous algorithm. It can be applied to the information service of charging stations and utilized as a reservation service.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.13-18
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• 1985

A set of utility programs for automatic generation, minimization and verification of high density PLA layout was developed, which includes equation-to-truth table translator, logic minimizer, PLA product term sorter, file generator for plotting stick diagram, dynamic CMOS PLA layout generator and bipartite row folded CMOS PLA layout generator. Size reduction is performed mainly by logic minimizer and bipartite row folder, and the maximal delay is reduced by sorter. The fOe for automatically generated layout is stored in CIF. Each program was written in Clanguage, and was run on VAX-11/750 (UNIX).

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.5
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• pp.77-85
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• 1997

A new technique using integer programming based on fuzzy multi-criteria function is proposed for generator maintenance scheduling. Minimization of maintenance delay cost and maximization of supply reserve power are considered for fuzzy multi-criteria function To obtain an optimal solution for gen- ,:rator maintenance scheduling under fuzzy environment, fuzzy multi-criteria integer programming is )used. In the maintenance scheduling, a characteristic feature of the presented approach is that the crisp conaitraints with uncertainty can be taken into account by using fuzzy set theory and so more flexible solution Ian he obtained. The effectiveness of the proposed approach is demonstrated by the simulation results.

• Proceedings of the KOR-KST Conference
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• 2000.02a
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• pp.89-115
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• 2000

Traffic signal setting policies and traffic assignment procedures are mutually dependent. The combined signal control and traffic assignment problem deals with this interaction. With the total travel time minimization objective, gradient based local search methods are implemented. Deterministic user equilibrium is the selected user route choice rule, Webster's delay curve is the link performance function, and green time per cycle ratios are decision variables. Three implemented solution codes resulting in six variations include intersections operating under multiphase operation with overlapping traffic movements. For reference, the iterative approach is also coded and all codes are tested in four example networks at five demand levels. The results show the numerical gradient estimation procedure performs best although the simplified local searches show reducing the large network computational burden. Demand level as well as network size affects the relative performance of the local and iterative approaches. As demand level becomes higher, (1) in the small network, the local search tends to outperform the iterative search and (2) in the large network, vice versa.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3502-3509
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• 2010

Streaming service in the wireless mobile network environment has been a very challenging issue due to the dynamic uncertain nature of the channels. Overhead such as congestion, latency, and jitter lead to the problem of performance degradation of an adaptive multi-streaming service. This paper proposes a AMSS (Adaptive Multi-level Streaming Service) mechanism to reduce the performance degradation due to overhead such as variable network bandwidth, mobility and limited resources of the wireless mobile network. The proposed AMSS optimizes streaming services by: 1) use of fuzzy similarity metric, 2) minimization of packet loss due to buffer overflow and resource waste, and 3) minimization of packet loss due to congestion and delay. The simulation result shows that the proposed method has better performance in congestion control and packet loss ratio than the other existing methods of TCP-based method, UDP-based method and VBM-based method. The proposed method showed improvement of 10% in congestion control ratio and 8% in packet loss ratio compared with VBM-based method which is one of the best method.