• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1269-1276
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• 2005

In this paper, Mixer using the direct-conversion method intended to use in front-end of a RF receiver is designed. The direct conversion Mixer is an alternative wireless receiver architecture to the well-established superheterodyne, particularly for high integration, low power, and low cost. It operates at 2.4GHz band, and is designed and simulated with a 0.35um CMOS technology and HSPICE simulator. Layout is implemented with a Mentor IC Station. The 2.4GHz CMOS Mixer employs a modified single-balanced Gilbert Cell with additional MOSFET in the output stages to improve IIP2, which is a standard of linearity in direct conversion receiver. Additional coversion-stages's transconductances are controlled by each MOSFET's physical properties. The HSPICE simulation results show that the 2.4GHz CMOS Mixer has voltage gam of 29dB, IIP2 of 63dBm, respectively. The Mixer also draws 3.5mA from a 3.3V supply.

• 한국IT서비스학회:학술대회논문집
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• 2002.06a
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• pp.96-107
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• 2002

21세기를 맞이하는 기업은 세계화와 국제화, 정보의 다양화 및 분산화, 제품수명주기의 단축과 수익률의 감소, 고품질의 제품, 지식산업의 등장, 고객 욕구의 증대 등 다양한 내 ${\cdot}$ 외적 환경변화에 대응해야 하고 경쟁우위를 확보하기 위해 끊임없이 기업의 변화능력을 확보해야 한다. 기업은 제품을 생산하여 판매하는 기업의 시스템 전체가 경쟁력을 갖추어 총체적 우위를 확보하고 고객의 기호와 감성에 호소하는 제품을 만들 수 있도록 다양한 정보를 제공하는 시스템을 필요로 하게 되었다. 즉, 시간과 서비스에 뒤진 고객지원체계는 기업의 성장에 절대적인 마이너스 요인이므로 고객 정보의 효율적 관리, 고객 요구에 대한 신속한 대응, 정기적 고객만족도 조사 등 고객이 원하는 것을 재빠르게 얻어낼 수 있는 고객 친밀형 정보시스템의 확립이 요구되는 것이다. 이를 해결해 줄 수 있는 새로운 경영정보시스템이 바로 WebERP인 것이다. WebERP는 기업의 원활한 자재, 구매활동을 위해 제안된 MRP에서 시작되었으며, 생산관리의 개념을 포함하고 있는 MRPII로 확대되었다가 다시 인사나 회계, 재무 등 조직이나 기업의 전업무영역을 수용하는 종합경영정보시스템으로 발전된 것이다. 현재는 전자상거래와 관련하여 WebERP의 필요성이 부각되었고, 모기업과 협력사간의 구매발주 및 납품관리를 확대시켜 소모성자재(MRO: Maintenance, Repair & Operation) 및 기타 공동구매서비스와 유사업종간의 그룹을 형성하여 ASP(Application Service Provider)의 공동 환경을 이용한 WebERP 환경을 이용한 WebERP활용이 현시점으로 적실히 필요한 것이다. 이는 중소기업들의 공동 협업체제를 도모하여 외세를 대비하는 응집력을 확고히 함으로써 집단체제의 e마켓플레이스 확립과 더불어 국제경쟁을 대비한 방안으로서 집단 공동의 웹환경 인프라가 필요한 것이다. 이러한 배경에서 ASP환경을 이용한 WebERP활용방안과 시스템 구축전략을 경남지역의 기계산업정보화사업단이 추진하는 일반기계, 전기기계, 금속기계, 수송기계, 정밀기계의 5개 업종을 4,877개 기업 대상으로 추진하고 있으며, 그 중 WebERP의 모델로서 2003년도까지 50개 기업을 선정하고, 이는 5개 업종 골고루 선정하여 적용과 표준화 모델로 전개해 나가는 것을 정리한 것이다.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.291-297
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• 2011

In this paper, the differential quantized method and the parallel method to reduce the size of ROM in the direct digital frequency synthesizer(DDFS) is proposed And we design the DDFS by FPGA The new ROM compression method can reduce the ROM size by using the two ROM. The quantized value of sine is saved by the quantized-ROM(Q-ROM) and the differential ROM(D-ROM). Also we design the phase-to-sine converter using the phase accumulator of parallel type for generating the high frequency. So the total size of the ROM in the proposed DDFS is significantly reduced compared to the original ROM The ROM compression ratio of 67.5% is achieved by this method. Also, the power consumption is decreased according to the ROM size reduction and we can design the DDFS generating the high frequency.

• KSBB Journal
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• v.9 no.5
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• pp.450-456
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• 1994

The effects of sucrose on cell growth and anticancer drug taxol production were investigated in cell suspension cultures of Taxus cuspidata. The cells were cultured at various concentrations of sucrose (20 to $100g/\ell$). The highest specific growth rata was achieved at $40g/\ell$ of sucrose as 0.076 day-1 and the highest final cell density, 34 g DCW/$\ell$ after 25 days of culture, was obtained at $60g/\ell$ of sucrose. The cell yield(Yx/s) was found to be 0.55g cell/g sucrose and doubling time (Td) was 9.12 day. High concentration of sucrose (80, $100g/\ell$) and the addition of osmoticum enhanced the production of taxol significantly. The maximum taxol production was $1.36mg/\ell$ at $80g/\ell$ of sucrose, which was 0.01% as a specific content.

• Clean Technology
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• v.18 no.4
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• pp.347-354
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• 2012

In this study, simulation works have been performed for the $CO_2$ removal process contained in the DME production process using NMP (N-methyl-2-pyrrolidone) as a solvent. PRO/II with PROVISION release 9.1 at Invensys was used as a chemical process simulator and NRTL activity coefficient model with Henry's law option and Soave-Redlich-Kwong equation of state were used for thermodynamic models. For the determination of the binary interaction parameters in NRTL model, regression works have been performed to match the experimental thermodynamic data. Optimal feed tray location which minimizes the reboiler heat duty was determined.

• Clean Technology
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• v.22 no.4
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• pp.241-249
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• 2016

In this study, comparative work has been performed between two-columns and three-columns configurations for an extractive distillation process to produce highly purified ethanol with not less than 99.7 wt% using dimethyl sulfoxide (DMSO) and ethylene glycol (EG) as extracting agents. Optimal ethanol concentration at a concentrator top stream which minimized the total reboiler heat duties was determined for a three-columns configuration for two different solvents. For the thermodynamic model, NRTL liquid activity coefficient model was used and PRO/II with PROVISION 9.4 at Schneider electric company was utilized. DMSO was proved to be a better solvent than EG and three-columns configuration is better than two- columns configuration in the total utility consumptions since some of the liquid water contained in the feed stream was removed at a concentrator bottom liquid stream.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1179-1182
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• 2016

In this paper, a new method to reduce the size of ROM in the direct digital frequency synthesizer (DDFS) is proposed. This method use the sine-linear phase difference method and differential PCM. The new ROM compression method can reduce the ROM size by using the two ROM. The quantized value of sine-linear phase difference is saved by the ROM1 of the $2^N$ sample period. The ROM2 save the difference between the original sine-linear phase difference value and the saved sample value of the ROM1. The ROM compression ratio of 37% is achieved by this method. Also, the power consumption is decreased according to the ROM size reduction.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1069-1076
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• 2017

Recently $Pok\acute{e}mon$ GO implements an online game with location-based real time augmented reality on mobile. The correct play of this game should be based on collecting the $Pok\acute{e}mon$ that appears as the user moves around by foot, but as the popularity increases, it appears an abuse to play easily. Many people have used an application that provides a mock location service such as Fake GPS, and these applications can be judged to be cheating in online games because they can play games in the house without moving. Detection of such cheating from a client point of view (mobile device) can consume a large amount of resources, which can reduce the speed of the game. It is difficult for developers to apply detection methods that negatively affect game usage and user's satisfaction. Therefore, in this paper, we propose a method to detect users abusing mock location service in online game by route analysis using GPS location record from the server point of view.

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.1-8
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• 2005

This paper is described on the development of KOTRON-13 and recent status of PET cyclotron by commercial cyclotron companies. KIRAMS has developed medical cyclotron which is KIRAMS-13. Samyoung Unitech produces KOTRON-13 with transfered technology by KIRAMS. As a part of Regional Cyclotron Installation Protect, KOTRON-13 cyclotrons and $[18F]FDG$ production modules are being installed at regional cyclotron centers in Korea. The medical concern with radiation technology has been growing for the last several years. Early cancer diagnosis through the cyclotron and PET-CT have been brought to public attention by commercial cyclotron models in the world. The new commercial cyclotron models are introduced compact low energy cyclotrons developed by CTI, GE, Sumitomo in recent. It produces different short-lived radioisotopes, such as $[^{18}F],\;[^{11}C],\;[^{13}N]\;and\;[^{15}O]$. For the better reliability acceleration particle is proton only. The characteristics of new model cyclotrons are changed to lower energy corresponding to less 13 MeV. New models have self-shielding and low power consumption. Design criteria for the different types of commercial cyclotrons are described with reference to hospital demands.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.200-202
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• 2019

북극해의 해빙 감소와 러시아 야말반도의 LNG 자원 개발 등으로 북극항로를 이용한 선박의 화물운송이 점차 증가하고 있다. 극지 해역 운항선박의 안전운항과 해양환경보호를 위하여 IMO Polar Code가 2017년 1월부터 강제 발효되었으며, SOLAS협약과 MARPOL73/78 협약에 추가되어 시행되고 있다. 이에 대응하기 위하여 해양수산부 해양안전 및 해양교통시설기술개발 사업으로 2014년 11월부터 2018년 12월까지 KRISO 주관으로 '북극항로를 운항하는 선박의 항해안전 지원시스템 개발' 과제를 수행하여 KRISO Arctic safe Routing System(KARS)을 개발하였다. 한편, Polar Code에서는 빙해구역을 운항하는 선박의 구조적인 안전성을 확보하기 위한 평가 기준으로 Polar Operational Limit Assessment Indexing System (POLARIS)을 제안하고 있다. 본 논문에서는 연구배경, KARS 및 POLARIS에 대해서 간략히 설명을 하고, 두 가지 방법으로 북극해 최적항로를 각각 시뮬레이션하여 그 차이를 비교 검토하여 보인다. 결과적으로 KARS는 POLARIS를 기본적으로 고려함으로서 선박의 구조적인 안전성을 확보함과 동시에 연료소모량을 최소화 하는 경로를 탐색하므로 보다 최적화된 경로를 줄 수 있다. 향후 지속적인 수정보완 작업을 통해서 완성도를 높여갈 예정이며, 검증단계를 거쳐서 최적하고 안전한 항로와 운항 관련 정보를 선사와 해기사에게 제공하고, 북극항로 중 단기 운항계획 수립과 항해사의 안전 운항을 지원할 수 있을 것으로 기대된다.