• 대한방사선기술학회지:방사선기술과학
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• 제39권1호
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• pp.99-105
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• 2016

잡음전력스펙트럼 (noise power spectrum, NPS)는 noise 진폭의 측정과 균일한 방사선 영역으로부터 획득된 영상의 품질에 가장 일반적인 방법 중 하나이다. 이 연구의 목적은 megavoltage X-ray 에너지를 사용하여 다른 잡음 전력스펙트럼 방법론들을 비교하는 것이다. 진단 영역에서의 잡음전력스펙트럼 평가 방법들은 국제 전기 규격 international electro-technical commission(IEC 62220-1) 기준을 사용하여 치료 영역에 적용되었다. 우리가 사용한 전자포털영상장치(electronic portal imaging device, EPID)는 Varian TrueBeam$^{TM}$, Siemens BEAMVIEW$^{PLUS}$, Elekta iViewGT 그리고 Varian Clinac$^R$ iX aS1000이었다. 잡음전력스펙트럼의 관심영역을 측정하기 위해, 우리는 겹침 (overlapping), 비겹침 (non-overlapping), 평탄도 (flatness), 반음영 (penumbra) 4가지 인자를 사용하였다. 결과적으로는 Siemens BEAMVIEW$^{PLUS}$, Varian TrueBeam$^{TM}$ flattening filter, Varian Clinac$^R$ iX aS1000, Varian TrueBeam$^{TM}$ flattening filter free에서의 잡음 (noise) 분포는 기존의 첫번째, 두번째, 세번째 실험방법보다는 Elekta iViewGT보다 현격하게 높은 noise 분포가 나타남을 알 수 있다. 이번 연구는 다양한 인자들이 잡음전력스펙트럼의 megavoltage imaging (MVI)영상에서 MVI영역에서 잡음전력 스펙트럼의 기준의 방법론으로 사용되어질 수 있다는 것을 보여주었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2718-2725
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• 2011

The VAL 208 in Uijeongbu Light Rail system is a light railway vehicle which could be operated in driverless supported by Siemens. It is a Rubber Wheel Type AGT (Automatic Guideway Transit). It will be operated in two car train about 11km of Uijeongbu line. In this paper, the technical overview of the ATC system and the interface between the system and the way side control equipments are presented. It includes the main functions of OBCU(On Board control Unit) and its information sharing method with WCU(Way side control Unit). The testing procedure of OBCU is also discussed.

• Structural Engineering and Mechanics
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• 제47권5호
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• pp.729-740
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• 2013

This paper addresses the structural design of the front end of Siemens ER24 locomotive body. The steel structure of the frontend is replaced with composite. Optimization of the composite lay-up is performed using Genetic Algorithms. Initially an optimized single design for the entire structure is presented. Then a more refined optimum is developed by considering the separate optimization of 7 separate regions of the structure. Significant savings in the weight of the structure are achieved.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2013년도 춘계학술대회 초록집
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• pp.146-147
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• 2013

최근 건축물이 대형화, 복잡화, 초고층화가 되어감에 따라 건축물의 변화에 대해 발생하고 있는 재난 재해는 더욱 다양해지고 대형화되어 가고 있다. 이러한 건축물의 변화에 대해 소방시설은 통합네트워크시스템을 구축하고 있으나, 우리나라와 미국은 시스템은 개별업체가 하고 있지만 수신기의 상호 시스템통합은 협의하지 않고 독립적이며 일본은 공업회에서 전용프로토콜을 사용하고 있었다. 수신기와의 상호 신호 전송방식은 Polling Addressing/RS-485과 P-MAST Polling Addressing이었다. 타 시스템과의 신호 상호연동은 3개사 모두 Ethernet 연결하고 있었으나 2개사는 광변환장치를 사용하였고 1개사는 Ethernet를 사용하였다.

• ETRI Journal
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• 제27권3호
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• pp.267-272
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• 2005

The transmission performance of optical labeling based on a combined frequency shift keying/amplitude shift keying (FSK/ASK) format is studied by numerical simulation. The simulation demonstrates that the bit-error ratio (BER) characteristic of an ASK signal is limited by the extinction ratio, received optical power, and dispersion, simultaneously. However, an FSK signal is mainly limited by the extinction ratio (ER) and received optical power when the peak spectrum, which is used to detect the FSK signal, is relatively narrow.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.235-240
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• 2001

The CHFG (Critical Heat Flux in Gap) test results have been evaluated to quantify the critical power in hemispherical narrow gaps and a new correlation has been developed. The CHFG test results have shown that increases in the gap thickness and pressure lead to an increase in critical power. The pressure effect on the critical power was found to be much milder than predictions by CHF correlations of other researches. From the CHFG test results, a new correlation on critical power in the hemispherical gap has been developed using the non-dimensional parameters as follows: $$\frac{qCHF}{{\rho}g^hfg}{\cdot}4\sqrt{\frac{{\rho}_g^2}{g{\sigma}{\Delta}{\rho}}=\frac{0.1042}{1+0.1375({\rho}g/{\rho}l)^{0.21}(D/s)}$$ The developed correlation has been expanded to apply the spherical geometry using the Siemens/KWU's correlation.

• 대한방사선기술학회지:방사선기술과학
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• 제17권2호
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• pp.13-20
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• 1994

The paper is on the record of radiography the patients with SIEMENS ANGIOSTAR/POLYTRON S PLUS angiosystem with DSA system in the Chonbuk National University Hospital from October 1993 to June 1994. The results are as follow : 1. Among the total No, 836 case of utilization, angiography are 316(37.8 %), interventional radiography are 256(34.2 %), and dacryocystography and sialography are 168(20/1 %). Therefore non-angiogrlphy procedure are incerasing. 2. The aomunt of contrast material used are half as much as conventional angiovascular system. 3. The amount of film consumed are $10{\sim}15%$ of that of conventional angio vascular system and reduction of procedure time are $40{\sim}50%$. 4. Admitting that dignostic utility is in the utilization by examination region, there should be technological study which deal with fine vessel and motion artifact problem.

• 한국유체기계학회 논문집
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• 제3권2호
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• pp.36-43
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• 2000

This study presents the centrifugal compressor performance for three different vane stagger angles and wall pressure distribution within vaned diffuser channels, and is also discussed about the stability with respect to the compressor components. As the vane stagger angle decreases, the flow rate for the stall onset decreases, and higher pressure can be obtained at the low flow rate region, however, the effective operation range of the compressor decreases because of the blockage effect of the diffuser vane. Low pressure pocket within the vaned diffuser channel moves from the pressure side of leading edge to the suction side as the flow rate decreases. The compressor system stability mainly depends on that of the diffuser.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.864-865
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• 2011

Battery Disconnecting System (BDS) is the important equipment in electric vehicle system. Therefore, most of electric vehicle companies, i.e. Hyundai Motors, Renault Motors, General Motors, want to have the reliability of 15 years - 150, 000 miles. Recently, reliability prediction through Siemens Norm SN 29500 is considered without testing. In this paper, we will introduce the standard and various input parameters. Also the case study will be shown for BDS. Prediction model is constructed by listing all the components of BDS. It calculates the $\pi$ factors for each components using the conversion equation in the standard and converts the reference failure rates to the expected operating failure rates. According to the result, the parts which will be improved are EV-Relays.

• Journal of Communications and Networks
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• 제12권5호
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• pp.442-448
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• 2010

Cooperative relaying methods have attracted a lot of interest in the past few years. A conventional cooperative relaying scheme has a source, a destination, and a single relay. This cooperative scheme can support one symbol transmission per time slot, and is caned full rate transmission. However, existing fun rate cooperative relay approaches provide asymmetrical gain for different transmitted symbols. In this paper, we propose a cooperative relaying scheme that is assisted with dual relays and provides full transmission rate with the same macro-diversity to each symbol. We also address equalization for the dual relay transmission system in addition to addressing the issues concerning the improvement of system performance in terms of optimal power allocations.