• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1037-1038
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• 2011

• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.384-392
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• 2005

Solvent effects on the kinetics of bromophenol blue fading have been investigated within a temperature range in binary mixtures of methanol, ethanol, 1-propanol, ethylene glycol and 1,2-propanediol with water of varying solvent compositions up to 40% by weight of organic solvent component. Correlation of logk with reciprocal of the dielectric constant was linear. Finally a mechanism was proposed for the bromophenol blue fading upon SESMORTAC (study of effect of solvent mixture on the one-step reaction rates using the transition state theory and cage effect) model, by means of this model, the fundamental rate constants of the fading reaction in these solvent systems were calculated.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.365-368
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• 2001

This paper described a design and implementation of the division/square-root for a redundant floating point binary number using high-speed quotient selector. This division/square-root used the method of a redundant binary addition with 25MHz clock speed. The addition of two numbers can be performed in a constant time independent of the word length since carry propagation can be eliminated. We have developed a 16-bit VLSI circuit for division and square-root operations used extensively in each iterative step. It peformed the division and square-root by a redundant binary addition to the shifted binary number every 16 cycles. Also the circuit uses the nonrestoring method to obtain a quotient. The quotient selection logic used a leading three digits of partial remainders in order to be implemented in a simple circuit. As a result, the performance of the proposed scheme is further enhanced in the speed of operation process by applying new quotient selection addition logic which can be parallelly process the quotient decision field. It showed the speed-up of 13% faster than previously presented schemes used the same algorithms.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1982-1983
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• 2001

직류 100 kV 까지 고전압의 국가 측정표준을 확립하기 위하여 저항형 분압기의 비율을 정밀 측정하는 방법을 고안하였다. 일반적으로 저항형 분압기의 비율은 사용 전압에 따라 변하므로 저항과 전압비율을 동시에 측정하는 기술이 요구된다. 본 발표에서는 고안된 binary step-up 방법의 원리를 설명하고 실제 적용 시 예상되는 불확도를 계산하고자 한다.

• 대한전자공학회논문지TE
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• 제37권5호
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• pp.7-16
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• 2000

본 논문은 고속 지수 선택기를 이용한 여분 부동 소수점 이진수의 제산/스퀘어-루트 설계 및 구현에 관하여 기술하였다. 본 제산/스퀘어-루트는 처리 속도 25㎒를 갖는 여분 이진수의 가산 방식을 사용하여 올림수 지연을 제거함으로써 비트 크기에 관계없이 일정한 시간으로 가산을 수행한다. 각각의 반복 단계에 널리 사용된 제산과 스퀘어-루트에 대해 16-비트 VLSI 회로를 설계하였다. 이것은 매번 16개 클럭마다 시프트된 이진수를 여분 가산하여 제산 및 스퀘어-루트를 실행한다. 또한 이 회로는 비복원 방법을 사용하여 지수 비트를 얻는다. 지수 선택 논리의 간단한 회로를 구현하기 위하여 나머지 비트의 주요 세 자리를 사용하였다. 결과적으로, 이 회로의 성능은 새로운 지수 선택 가산 논리를 적용하여 지수 결정 영역을 병렬 처리함으로써 한층 더 연산 처리 속도를 높인 것이다. 이전에 동일한 알고리즘을 사용하여 제안된 설계보다 13% 빠른 속도 증가를 보였다.

• 전기학회논문지
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• 제58권4호
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• pp.806-816
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• 2009

Character recognition system consists of four step; text localization, text segmentation, character segmentation, and recognition. The character segmentation is very important and difficult because of noise, illumination, and so on. For high recognition rates of the system, it is necessary to take good performance of character segmentation algorithm. Many algorithms for character segmentation have been developed up to now, and many people have been recently making researches in segmentation of touching or overlapping character. Most of algorithms cannot apply to the text regions of management number marked on the slab in steel image, because the text regions are irregular such as touching character by strong illumination and by trouble of nozzle in marking machine, and loss of character. It is difficult to gain high success rate in various cases. This paper describes a new algorithm of character segmentation to recognize slab management number marked on the slab in the steel image. It is very important that pre-processing step is to convert gray image to binary image without loss of character and touching character. In this binary image, non-touching characters are simply separated by using vertical projection profile. For separating touching characters, after we use combined profile to find candidate points of boundary, decide real character boundary by using method based on recognition. In recognition step, we remove noise of character images, then recognize respective character images. In this paper, the proposed algorithm is effective for character segmentation and recognition of various text regions on the slab in steel image.

• 제어로봇시스템학회논문지
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• 제12권3호
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• pp.208-220
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• 2006

Energy of wheeled mobile robot is usually supplied by batteries. In order to extend operation time of mobile robots, it is necessary to minimize the energy consumption. The energy is dissipated mostly in the motors, which strongly depends on the velocity profile. This paper investigates various 3-step (acceleration - cruise - deceleration) speed control methods to minimize a new energy object function which considers the practical energy consumption dissipated in motors related to motor control input, velocity profile, and motor dynamics. We performed an analysis on the energy consumption various velocity profile patterns generated by standard control input such as step input, ramp input, parabolic input, and exponential input. Based on these standard control inputs, we analyzed the six 3-step velocity profile patterns: E-C-E, P-C-P, R-C-R, S-C-S, R-C-S, and S-C-R (S means a step control input, R means a ramp control input, P means a parabolic control input, and E means an exponential control input, C means a constant cruise velocity), and suggested an efficient iterative search algorithm with binary search which can find the numerical solution quickly. We performed various computer simulations to show the performance of the energy-optimal 3-step speed control in comparison with a conventional 3-step speed control with a reasonable constant acceleration as a benchmark. Simulation results show that the E-C-E is the most energy efficient 3-step velocity profile pattern, which enables wheeled mobile robot to extend working time up to 50%.

• Transactions on Electrical and Electronic Materials
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• 제3권3호
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• pp.8-13
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• 2002

Controlled precipitation of quasi-binary semiconductor system is newly proposed as an effective and reliable technique for the formation of well-defined and crystallographically aligned semiconductor nanostructures. Using HgTe-PbTe quasi-binary semiconductor system, self-aligned HgTe nanocrystallites distributed three dimensionally within PbTe matrix were successfully formed by the simple three step heat treatment process routinely found in age hardening process of metallic alloys. Examination of the resulting nano precipitates using conventional transmission electron microscopy (CTEM) and high resolution TEM (HRTEM) reveals that the coherent HgTe precipitates form as thin discs along the (100) habit planes making a crystallographic relation of {100}$\_$HgTe///{100}$\_$PbTe/ and [100]$\_$HgTe///[100]$\_$PbTe/. It is also found that the precipitate undergoes a gradual thickening and a faceting under isothermal aging up to 500 hours without any noticeable coarsening. These results, combined with the extreme dimension of the precipitates (4-5 nm in length and sub-nanometer in thickness) and the simplicity of the formation process, leads to the conclusion that controlled precipitation is an effective method for preparing desirable quantum-dot nanostructures.

• 전기학회논문지
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• 제63권11호
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• pp.1622-1625
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• 2014

The main measurement uncertainty factors in DC high-voltage dividers for a national high-voltage standard are the measurement uncertainty of low-voltage arm and the stability of a high-voltage supply. In this study, the uncertainties by the two factors are greatly improved. As a result the measurement uncertainty for the DC high-voltage divider is reduced from $16{\times}10^{-6}(k=2)$ to $8{\times}10^{-6}(k=2)$ which is at international level.

• 한국주조공학회지
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• 제37권4호
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• pp.108-114
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• 2017

In this study, we investigated the effect of the Si content on the secondary dendrite arm spacing (SDAS) of hypoeutectic Al-Si binary alloys in the range of 4~10 wt% Si. Cooling curves were measured during the solidification of the alloy cast in a step-wise mold. We compared two kinds of solidification time: the first is the total solidification time for both dendritic and eutectic growth, and the second is the solidification time for only dendritic growth. The proportional constant in the relationship between SDAS and cooling rate was estimated, as this constant represents the stability of the cast microstructure. The proportional constant decreased with the Si contents from 4 wt% to 8 wt%, and it remains relatively uniform with up to 10 wt% of Si.