• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.60-68
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• 2006

소수 station의 수소분리정제를 위한 compact형 PSA 공정을 연구하였다. 기존 PSA 공정의 흡착탑이 차지하는 시스템의 공간을 줄이기 위하여 하나의 흡착탑 안에 다른 흡착탑을 넣어 흡착탑이 차지하는 공간을 최소화하였으며, 흡착탑 간의 열교환이 효과적으로 일어나도록 설계하였다. 수소 혼합물에 대한 활성탄으로 충진된 dual bed에서의 수소 혼합물에 대한 흡/탈착 동특성 실험을 실시하였으며, 시간에 따른 농도와 온도의 변화를 측정하였다. 수소 혼합물로는 $H_2/CO/CH_4/CO_2$ (69:2:3:26 vol.%) 를 사용하였으며, 흡착유량은 7LPM, 흡착압력은 9atm 조건에서 운전하였다. Inner bed와 outer bed의 성능은 각각의 열전달 특성의 차이로 인하여 다르게 나타났으나, 단일탑의 동특성보다는 우수한 성능을 보이고 있었다. 따라서 개발된 dual bed는 적은 부지를 차지하면서도, 보다 우수한 수소 분리 성능을 보일 수 있는 PSA 공정에 응용될 수 있음을 확인하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.233-235
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• 2007

현재 기존 철송 시스템에 있어서 문제점인 출발지와 목적지 사이 발생하는 복잡한 작업 프로세스(job process)를 간소화하여 철송 운임비감소와 물류운송의 체계 개선 및 활성화에 기여할 수 있는 시스템으로 DMT(Dual Mode Trailer) 시스템을 들 수 있다. 이에 본 기술의 국내적용 및 개발을 위해 기술동향 조사 및 국내 적용시 고려사항, 국내 적용 접합 모델 도출 등 그 기술성을 분석하였다.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.5
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• pp.342-350
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• 2013

Dual response surface optimization (DRSO), inspired by Taguchi's philosophy, attempts to optimize the process mean and variability by using response surface methodology. Researches on DRSO were extensively done in 1990's and have been matured recently. This paper reviews the existing DRSO methods from the decision making perspective. More specifically, this paper classifies the existing DRSO methods based on the optimization criterion and the timing of preference articulation. Also, some of case studies are reviewed. Extension to multiresponse optimization, triple response surface optimization, and application of data mining method are suggested as future research issues.

• Journal of Biomedical Engineering Research
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• v.8 no.2
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• pp.171-176
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• 1987

Wiener filtering method was applied to the dual energy imaging procedure in digital radiography(D.R.). A linear scanning photodiode arrays with 1024 elements(0.6mm H 1.3mm pixel size) were used to obtain chest images in 0.7 sec. For high energy image acquisition, X-ray tube was set at 140KVp, 100mA with a rare-earth phosphor screen. Low energy image was obtained with X-ray tube setting at 70KVp, 150mA. These measured dual energy images are represented in the vector matrix notation as a linear discrete model including the additive random noise. Then, the object images are restored in the minimum mean square error sense using Wiener filtering method in the transformed domain. These restored high and low energy images are used for computation of the basis image decomposition. Then the basis images are linearly combined to produce bone or tissue selective images. Using this process, we could improve the signal to noise ratio characteristics in the material selective images.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1546-1548
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• 1998

Dual mode ring resonators(DMRR) have been fabricated using laser ablated $YBa_2Cu_3O_{7-x}$ superconducting thin films. The transition temperature of YBCO thin films were 85 - 88 K and the film thicknesses were about 5,000 $\AA$. Dual mode ring resonators were patterned by standard photolithography process and wet-etching. Then two-layer metal thin films (Ti/Ag) have been deposited for the ground plane on the back side of substrate by e-beam and thermal evaporation. The input/output feedline angles of each resonator were $60^{\circ}$, $100^{\circ}$, $180^{\circ}$. A network analyzer was used for testing the performance of the resonators in the frequency range of 6-13 GHz at 77 K.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.435-436
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• 2008

This paper presents a dual band frequency synthesizer for GSM and Wideband CDMA which is designed in a standard 0.13um CMOS 1P6M process. The shared components include phase frequency detector (PFD), charge pump (CP), loop filter, integer frequency divider(128/129 DMP, 4bit PC, 3bit SC) and Low noise Ring-VCO. A high-speed low power dual modulus prescaler is proposed to operate up to 2.1GHz at 3.3V supply voltage with 2mW power consumption by simulation. The simulated phase noise of VCO is -101dBc/Hz at 200kHz offset frequency from 1.9GHz.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.417-420
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• 2003

Most Embedded Web Camera Server products currently deployed on the market adopt JPEG for compression of video data continuously acquired from the cameras. However, JPEG does not efficiently compress the continuous video stream, and is not appropriate for the Internet where the transmission bandwidth is not guaranteed. In our previous work, we presented the result of designing and implementing an embedded web camera streaming server using MPEG4 codec. But the server in our previous work did not show good performance since one CPU had to both compress and process the network transmission. In this paper, we present our efforts to improve our previous result by using dual CPUs, where DSP is employed for data compression and StrongARM is used for network processing. Better performance has been observed, but it is found that still more time is needed to optimize the performance.

• Journal of IKEEE
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• v.14 no.1
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• pp.40-46
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• 2010

This paper describes a clock and data recovery (CDR) circuit that supports dual data rates of 2.7Gbps and 1.62Gbps for DisplayPort standard. The proposed CDR has a dual mode voltage-controlled oscillator (VCO) that changes the operating frequency with a "Mode" switch control. The chip has been implemented using $0.18{\mu}m$ CMOS process. Measured results show the circuit exhibits peak-to-peak jitters of 37ps(@2.7Gbps) and 27ps(@1.62Gbps) in the recovered data. The power dissipation is 80mW at 2.7Gbps rate from a 1.8V supply.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.828-831
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• 2003

This paper presents a novel design technique and characteristic analysis of Magnet for dual air-gap axial-flux type permanent-magnet synchronous generator. The process of magnet design is applied to the motor design and steady state analysis considering output voltage waveforms and magnetic flux waveforms. Design and construction of an axial-flux permanent-magnet generator with power output at 60 [Hz], 300[r/min] is introduced. Finite-element (FE) method is applied to analyze magnet shape characteristics. The results of FE analysis show generator is feasible for use with dual air-gap axial-flux permanent- magnet synchronous generator.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.4
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• pp.134-141
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• 2005

Due to the complexity and stochastic nature of automated warehousing system, items are usually queued up at I/O point. We introduce a storage/retrieval policy : dual-command. We present quick approximations to queueing phenomena under these policies. It is assumed that the storage and retrieval arrival pattern follow the same poisson process. We also assumed that storage queue and retrieval queue being operated separately. The approximation attempts are performed under the proposed storage/retrieval policies after we derive S/R machine travel time distributions.