• 한국산학기술학회논문지
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• 제10권10호
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• pp.2935-2944
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• 2009

중소 PCB 제조업체에서는 외부 생산 환경 변화, 복수개의 제약공정, 많은 공정수, 긴 리드타임, 동일공정 반복생산 등의 특징으로 인하여 효과적인 생산 스케쥴 작성에 많은 어려움을 겪고 있다. 최근 TOC 이론에서 제시하고 있는 DBR기법을 PCB 생산라인에 적용하고자 하는 시도는 진행되고 있으나, 제약공정을 1개만 설정하도록 하는 일반적인 DBR로서는 PCB 생산라인의 특성상 충분한 효과를 기대할 수 없는 현실이다. 따라서 본 논문에서는 PCB 생산라인에서 효과적인 생산스케줄링을 수립하기 위하여 TOC의 DBR기법을 발전시킨 복수 DBR기법을 제시하였다. 또, 실제로 국내 중소 PCB 제조업체에 복수 DBR을 적용하여 제조 리드타임을 20%이상 단축함을 확인하였다.

• Journal of Positioning, Navigation, and Timing
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• 제3권2호
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• pp.71-81
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• 2014

Time synchronization system using dual frequency bands is designed and the error sources are analyzed for alternative synchronized-pseudolite navigation system (S-PNS) which aims at military application. To resolve near/far problem, dual frequency band operation is proposed instead of pulsing transmission which degrades level of reception. In dual frequency operation H/W delay should be considered to eliminate errors caused by inter-frequency bias (IFB) difference between the receivers of the pseudolites and users. When time synchronization is performed across the sea, multipath error is occurred severely since the elevation angle between pseudolites is low so total reflection can be happened. To investigate the difference of multipath effects according to location, pseudolites are set up coastal area and land area and performances are compared. The error source related with tropospheric delay is becoming dominant source as the coverage of the PNS is broadening. The tropospheric delay is measured by master pseudolite receiver directly using own pseudorange and slave pseudorange. Flight test is performed near coastal area using S-PNS equipped with developed time synchronization system and test results are also presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.46-51
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• 2001

To reach high areal density, less track pitch is expected and more servo bandwidth is required. One approach to overcoming the problem is by using dual stage servo system. In this system, a voice coil motor (VCM) is used as the primary stage while a milliactuator is used as the secondary stage. We have suggested new milliactuator based on the shear mode of piezoelectric elements to drive the head suspension assembly. In this paper, we introduce controller design method, PQ method. PQ method reduces the controller design problem for DISO(dual-input/single-output) systems to two standard controller design problems for SISO(single-input/single-output) problems. The first part of PQ method directly address the issue of actuator output contribution, and the second part allows the use of traditional loop shaping to achieve the overall system performance. This paper shows how to employ the PQ method to meet aggressive close-loop performance specifications for a disk drive system with a VCM and piezoelectric milliactuator.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.672-677
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• 2004

In this paper, a new dual-rate digital control technique for the Takagi-Sugeno (T-S) fuzzy system is suggested. The proposed method takes account of the stabilizablity of the discrete-time T-S fuzzy system at the fast-rate sampling points. Our main idea is to utilize the lifted control input. The proposed approach is to obtain the dual-rate discrete-time T-S fuzzy system by discretizing the overall dynamics of the T-S fuzzy system with the lifted control, and then to derive the sufficient conditions for the stabilization in the sense of the Lyapunov asymptotic stability for this system. An example is provided for showing the feasibility of the proposed discretization method.

• Journal of Advanced Marine Engineering and Technology
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• 제18권5호
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• pp.78-87
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• 1994

In this paper design and implementation of ship's distributed remote control system using dual-microprocessor is presented for real time process. The proposed system is implemented with the single chip microprocessors in tightly coupled mode and results in speed up of $s_p$=1.74. Under the assumption that the nodes are interconnected in multidrop, the overall system performance such as average throughout-delay characteristics and effective throughput are analyzed using M/G/1 queneing model, and results show that the proposed node can be used in medium sized distributed monitoring and control system.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권2호
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• pp.199-204
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• 2004

In this paper, a new dual-rate digital control technique for the Takagi-Sugeno (T-S) fuzzy system is suggested. The proposed method takes account of the stabilizablity of the discrete-time T-S fuzzy system at the fast-rate sampling points. Our main idea is to utilize the lifted control input. The proposed approach is to obtain the dual-rate discrete-time T-S fuzzy system by discretizing the overall dynamics of the T-S fuzzy system with the lifted control, and then to derive the sufficient conditions for the stabilization in the sense of the Lyapunov asymptotic stability for this system. An example is provided for showing the feasibility of the proposed discretization method.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.493-495
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• 2007

Future sub-meter resolution LEO missions require simultaneous dual-polarization downlink and/or multiple channel downlinks in single polarization. Especially, dual-polarization is needed to cope with bandwidth limitation due to high speed data transmission. Current KARI 13m X-Band antenna system needs to be upgraded to cope with such downlink schemes. This paper describes brief discussions on engineering work regarding how to meet the new requirements with minimum impact on current system as well as C&M (Control and Monitoring) software.

• 한국항해항만학회지
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• 제34권2호
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• pp.137-144
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• 2010

In light of the growing traffic congestion problem and congestion cost, the container transport by railway has to be increased. The freight transport by railway can have decided advantages over trucks in terms of energy efficiency, emissions and cost for certain freight movements, just as transportation in the metropolitan region can have great advantages over driving truck. But the freight transport by truck should gain significant mobility benefits from a freight railway system. Thus, the DMT(Dual Mode Trailer) transport system which is coupled railway transport advantages with load transport advantages has been developed and used in the european countries. The DMT transport will therefore serve the areas required by transport organizers. The purpose of this paper is to estimate economical feasibility analysis for development of DMT transport system. Consequently, this study analyzed the characteristics of the DMT system. The horizontal load.unload system is being considered as an adoptable DMT system in consideration of the situation in Korea.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2321-2323
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• 1998

A control system using a PLC has been developed for a dual tower drier(DTD) in a CANDU type nuclear power plant. This system will replace the existing DTD control system which was implemented with mechanical timers and relays. The new control system makes it possible for an operator to perform more precise time and dew point control for the DTD, thanks to the high efficiency and flexibility of the PLC. The operational cost for the control system is much reduced compared to the existing system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.289-292
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• 2001

A Dual rotor turbines HAWT/VAWT combined wind turbine system that can drastically enhance the power production capability compared to conventional Single Rotor Turbine HAWT system. The combined system that takes advantage of strong point of both horizontal and vertical Axis wind turbine system developed by a venture firm : KOWINTEC of Chonbuk National University. The HAWT/VAWT hybrid system has been successfully field tested and commercial operation since Feb. 12, 2001 in Hae-chang rest park, Bu-an county near the Sae Man-Kum Sea Dike. This paper will briefly describe the field test results performance and a special aerodynamic structure with bevel-planetary gear box of Dual Rotor Wind Turbine system.