• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 하계종합학술대회 논문집
• /
• pp.914-917
• /
• 1999

The paper describes a 17 $\times$ 17-b multiplier using the Radix-4 Booth’s algorithm. which is suitable for 32-bit RISC/DSP microprocessors. To minimize design area and achieve improved speed, a 2-stage pipeline structure is adopted to achieve high clock frequency. Each part of circuit is modeled and optimized at the transistor level, verification of functionality and timing is performed using HSPICE simulations. After modeling and validating the circuit at transistor level, we lay it out in a 0.35 ${\mu}{\textrm}{m}$ 1-poly 4-metal CMOS technology and perform LVS test to compare the layout with the schematic. The simulation results show that maximum frequency is 330MHz under worst operating conditions at 55$^{\circ}C$ , 3V, The post simulation after layout results shows 187MHz under worst case conditions. It contains 9, 115 transistors and the area of layout is 0.72mm by 0.97mm.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2016년도 추계 학술논문 발표대회
• /
• pp.113-114
• /
• 2016

In this study, various fats and oils were soaked in low-strength mortar to experiment what kind of fats and oils had the worst effect on low-strength mortar; it went as follows. For rate of change in length of fat and oil soaking, there was an increase in the order of pig fat, bio-diesel, grape seed oil, and water; in the case of olive oil it was destroyed within 56 days. For rate of change in mass, there was an increase in the order of bio-diesel, water, pig fat, grape seed oil, and olive oil. For relative motion elastic coefficient, there was a decrease in the order of olive oil, grape seed oil, and water. On the whole, pig fat, bio-diesel, and olive oil were shown to have the worst effect on low-strength mortar.

• 대한전자공학회논문지TC
• /
• 제37권4호
• /
• pp.17-24
• /
• 2000

통신을 위한 채널로써 전력선을 활용하기 위해서, 전력선상에서 존재하는 잡음을 측정하여 잡음 데이터를 획득하고, 망구조에 따른 단위길이(100m당)에 따른 신호 감쇄량을 측정했다. 본 논문에서 구분한 3종류의 전력선 구조에 따른 신호 감쇄와 잡음의 최대, 최소값을 이용해서 채널 용량식에 대입한 후 통신 채널로써 전력선이 가지는 채널용량을 계산하였다. 건물내 전력선이 가지는 채널용량은 전력선에 있어서 송,수신기 사이의 거리와 전력선 망구조에 영향을 크게 받는 것으로 나타났다.

• Journal of the Korean Data and Information Science Society
• /
• 제10권2호
• /
• pp.289-298
• /
• 1999

We consider a minimax approach to make a design robust to many types or uncertainty arising in reality when dealing with non-normal linear models. We try to build a design to protect against the worst case, i.e. to improve the "efficiency" of the worst situation that can happen. In this paper, we especially deal with the generalized linear model. It is a known fact that the generalized linear model is a universal approach, an extension of the normal linear regression model to cover other distributions. Therefore, the optimal design for the generalized linear model has very similar properties as the normal linear model except that it has some special characteristics. Uncertainties regarding the unknown parameters, link function, and the model structure are discussed. We show that the suggested approach is proven to be highly efficient and useful in practice. In the meantime, a computer algorithm is discussed and a conclusion follows.

• KIEE International Transactions on Power Engineering
• /
• 제5A권1호
• /
• pp.16-21
• /
• 2005

In this study, a new Unit Commitment (UC) algorithm is proposed to consider the uncertainty of a daily load profile. The proposed algorithm calculates the UC results with a lower load level than that generated by the conventional load forecast method and the greater hourly reserve allocation. In case of the worst load forecast, the deviation of the conventional UC solution can be overcome with the proposed method. The proposed method is tested with sample systems, which indicates that the new UC algorithm yields a completely feasible solution even when the worst load forecast is applied. Also, the effects of the uncertain hourly load demand are statistically analyzed, particularly by the consideration of the average over generation and the average under generation. Finally, it is shown that independent power producers participating in electricity spot-markets can establish bidding strategies by means of the statistical analysis. Therefore, it is expected that the proposed method can be used as the basic guideline for establishing bidding strategies under the deregulation power pool.

• 한국대기환경학회지
• /
• 제31권4호
• /
• pp.319-329
• /
• 2015

The characteristics of aerosol light extinction were investigated by comparing measured and calculated extinction coefficient to understand the contribution of air pollutants on visibility impairment for data during 4 months (Jan~ April), 2014. The integrated nephelometer and aethalometer system were installed to measure the scattering and absorption coefficients of aerosol as well as BAM 1020, MARGA, semi-continuous OCEC analyzer, and online-XRF to calculate the extinction coefficient. The IMPROVE_2005 equation was used to determine the contributions of different chemical components on visibility impairment in $PM_{2.5}$ and $PM_{10}$ due to highest correlation with measured data. Sulfate, nitrate, and organic mass by carbon (OMC) of fine aerosol were the major contributors affecting on visibility impairment. Total contributions to light extinction were calculated as $631.0Mm^{-1}$ for the worst-case and $64.4Mm^{-1}$ for the best-case. The concentrations of aerosol component for the worst-case were 38.4 times and 45.5 times larger than those of the best-case for $(NH_4)_2SO_4$ and $NH_4NO_3$, respectively. At lower visibility condition, in which extinction coefficient was higher than $400Mm^{-1}$, extinction coefficient varied according to the relative humidity variation regardless of $PM_{2.5}$.

• Journal of Astronomy and Space Sciences
• /
• 제29권3호
• /
• pp.305-313
• /
• 2012

We conducted thermal analyses and cooling tests of the space observation camera (SOC) of the multi-purpose infrared imaging system (MIRIS) to verify passive cooling. The thermal analyses were conducted with NX 7.0 TMG for two cases of attitude of the MIRIS: for the worst hot case and normal case. Through the thermal analyses of the flight model, it was found that even in the worst case the telescope could be cooled to less than $206^{\circ}K$. This is similar to the results of the passive cooling test (${\sim}200.2^{\circ}K$). For the normal attitude case of the analysis, on the other hand, the SOC telescope was cooled to about $160^{\circ}K$ in 10 days. Based on the results of these analyses and the test, it was determined that the telescope of the MIRIS SOC could be successfully cooled to below $200^{\circ}K$ with passive cooling. The SOC is, therefore, expected to have optimal performance under cooled conditions in orbit.

• 한국지능시스템학회논문지
• /
• 제18권4호
• /
• pp.572-578
• /
• 2008

본 논문에서는 대규모 베이지안 망 구조 학습을 위해 제안되었던 R-CORE 방법의 탐색 공간의 크기에 대한 개략적인 분석과 실제 문제에 적용하였을 경우의 효과에 대한 실험적 결과를 제시한다. R-CORE 방법은 베이지안 망 구조 학습의 탐색 공간을 축소하기 위해 제안된 확률변수들의 재귀적 군집화와 오더 제한 방법이다. 알려진 벤치마크 베이지안 망을 이용한 분석을 통해, 제안되었던 R-CORE 방법이 worst case에는 기존의 방법과 유사한 탐색 공간을 가지나 평균적으로 기존방법보다 훨씬 적은 탐색 공간만을 고려한다는 것을 보인다. 또한 평균적으로 훨씬 적은 탐색 공간만을 고려하는 결과, 구조 탐색에서 기존 방법에 비해 상대적으로 적은 overfitting이 일어남을 실험적으로 보인다.

• 전자공학회논문지 IE
• /
• 제45권1호
• /
• pp.44-49
• /
• 2008

본 논문에서는 중계기의 군 지연 및 이득 변동 특성을 포함한 비선형 위성 채널에서 다중 레벨 QAM 방식을 적용한 OFDM 기반 시스템에 대하여 성능을 분석하였다. 일반적인 OFDM을 적용하는 경우와 반송파 간섭 OFDM을 적응하는 경우를 부가 백색 가우시안 잡음 환경에서 지정된 위성 채널의 비선형 정도에 대하여 적용한 QAM 방식에 따른 BER 성능을 비교하여 성능 개선 정도를 제시하였다. 36MHz 대역폭의 중계기 채널에 120Mbps 전송률의 정보를 QPSK, 8QAM, 16QAM, 32QAM, 64QAM을 사용하여 전송하는 경우에 대하여 위성 채널의 특성을 통상적인 경우와 최악 조건의 경우로 나누어 모의실험을 적용하였다. 모의실험 결과를 통하여 통상적인 채널 환경에서 고차 레벨의 QAM을 적용하는 경우에 반송파 간섭 OFDM에 의한 개선 정도가 이득 변동 특성보다는 성능 열화에 상대적으로 심각한 영향을 미치는 군 지연과 고출력 증폭기의 비선형 특성에 의한 개선 정도가 두드러지게 나타남을 확인할 수 있었다. 아울러 최악의 조건의 경우에 32QAM 이상의 QAM-OFDM을 적용하는 경우에는 채널 부호화나 비선형 특성의 보상 방법과 같은 추가의 기법이 필요함을 알 수 있었다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 춘계학술대회 논문집
• /
• pp.299-307
• /
• 2005

The 180 km/h Korean Tilting Train(TTX) which is now developing as a part of the Korean National R&D project, was elaborately designed. As the tilting trains run curve track with the $30\%$ higher speed than normal trains, the higher centrifugal and dynamic force are expected. Furthermore the complex tilting system increase the probability of failure. Therefore it is very important for tilting train to ensure safety against derailment under the various kind of failed condition in the middle of running as well as normal operating condition. The TTX train have the relatively high roll stiffness to improve the lateral ride comfort and to limit the roll displacement on the curve. But the higher roll stiffness increase the risk of derailment on the twisted track. This paper describes the study to review the safety against derailment caused by the wheel unloading on the severely twisted track. The worst combination of maximum cant change with maximum twist defect was established by numerical simulation. And also it was assumed that the air bag deflated and still the train run its speed limit. Those kind of assumption might be the worst case from the view point of wheel unloading derailment on the twisted track. The dynamic simulation was done by means of VAMPIRE S/W and non-linear transient analysis. We found that derailment quotients Q/P was only slightly influenced by track twist but the wheel unloading was greatly influenced. And we ascertained that the higher roll stiffness the higher wheel unloading. In case of air bag deflated situation, the wheel unloading reached up to $100\%$ which means the wheel lift or jumped. Therefore it was concluded that the design need to be improved to ensure the safety against derailment on the maximum twisted track in case of air bag deflated and tilting train's speed limit.