• Journal of the Institute of Electronics Engineers of Korea SC
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• 제37권3호
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• pp.9-18
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• 2000

This paper presents methods for reducing odometer errors caused by kinematic imperfections in wheeled mobile robots. Wheel diameters and wheelbase are corrected by using encoders without landmarks. And a new velocity trajectory is proposed that compensates for an orientation error due to acceleration-resolution constraints on motor controllers. Based on this velocity trajectory, the wheel velocity of one out of two driven wheels may be changed by the traveled distance of the mobile robot. It is shown that a wheeled mobile robot can't move along a straight line exactly, even if kinematic correction are achieved perfectly, and this phenomenon is attributable to acceleration-resolution constraints on motor controllers. We experiment on a wheeled mobile robot with 2 d.o.f. and discuss the results.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제26권5D호
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• pp.723-730
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• 2006

Recently, The flexible moving block system in train operation has been introduced to the worldwide rail transportation markets. This paper is a comparative study of the conventional fixed block systems effects and the flexible moving block system on train operating time saving. Based on the literature review, the new algorithm is developed. It is to calculate the optimum headway time of the train. The proposed algorithm can overcome some of the existing algorithm problems, such as the limits of the data and unaware of the rail characteristic. The total travel time saving effect has been analyzed by applying the skip stop scheduling system to the each block system. The results of this study indicated that the total travel time is approximately 40% decreased and the schedule velocity is approximately 24% improved when the moving block system is applied. The results of this study could be used as a theoretical basis for the selection of rail signal system in Seoul's subway number 2 line.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.200-203
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• 2006

지역의 공간 분포가 내포된 고해상도의 지상강우량을 추정하기 위해서 강수와 구름 입자(고체와 액체)의 양과 성질을 반영한 기상레이더의 반사도(reflectivity) 자료로부터 지상강우강도로 환산하는 방법이 널리 이용된다. 반사도 (reflectivity) 자료로부터 지상강우강도로 환산하는 핵심은 Z-R 관계식으로, 이 Z-R 관계식의 매개변수 a와 b의 결정이 중요하다. 그러나, 지상우량 관측소에서 측정되는 강우량 자료는 지상에서 관측된 강우자료이나, 레이더에서 추정되는 강우량은 상공 (이 연구에서는1.5km)에서 관측한 반사도로 추정되는 값으로 이에 상응하는 오차를 줄이기 위하여 보정하는 기법이 이용된다. 수계내의 정확한 유출량을 모의계산하기 위하여 수문수치모형이 이용되며, 이의 보다 정확한 수치결과를 모의하기 위해서 레이더 강우추정을 사용하여 정확도를 높이고자 하는 연구가 진행 중이다. 이 연구에서는 기상청에서 운영하는 레이더 반사도 자료를 사용하여 용담/남강유역 내에서 2002-2004년의 집중호우에 대해 Z-R 관계식을 추정하고, 유역 내 평균 강우량과 지상관측 강우량의 비 (G-R비)를 이용한 공간적 특성을 고려한 보정을 함으로써 추정된 평균 강우량의 정확도를 향상시켰다. 이렇게 추정된 레이더 강우는 지상관측지점 강우만으로 보간 된 강우(gauge-only interpolation)와 비교 되어, 레이더강우의 정확성과 적용성이 수문모형에 적합한가를 평가해 보았다. 공간적 분포의 특성을 내포하며 강우예측 (Quantitative Precipitation Forecasting)에 이용될 수 있다는 잇점은 있으나, 레이더 강우 추정은 정확성과 적용성에 많은 의문점을 남긴다.리 전도도 값을 Gardner 식에 적용하여 1, 3, 5, 7kPa에서의 불포화수리 전도도 값을 17개 토양통을 대상으로 하여 구했다. 토양수분 potential이 3kPa에서는 물의 이동이 거의 없는 토양들이 있었는데 반해 남계통을 비롯한 학곡통, 회곡통, 백산통, 상주통, 석천통, 예산통 등 7개의 토양은 3kPa에서도 약간의 물의 이동이 있었다. 이는 모암이 화강 편마암인 관계로 토양 내에 물의 이동에 영향을 미치는 자갈의 함량이 높았기 때문일 것으로 생각되고 추후의 연구에서는 이 부분에 대한 내용도 검토되어야 할 것이다. 또한, 1kPa에서 물의 이동은 삼각통에서 35.21 cm/day로 이동 속도가 가장 컸으며 그 뒤로 예산통, 화봉통, 학곡통, 백산통 등이 토양에서 빠른 속도로 이동하였다. 가천통이나 석천통 및 우곡통은 1kPa에서의 이동 속도가 아주 느린 토양으로 판단되었다. 또한, 포화되지 않은 상태인 1kPa에서 물의 이동 속도를 VGM 모형에 의해 예측된 값과 측정된 값으로 비교하였을 때 불포화 수리 전도도가 예측되지 않은 토양(석천통, 지곡통, 풍천통)이 존재하여 불포화 수리 전도도 특성평가에 대한 VGM 모형의 적용성에 문제를 보였다. 이는 결과적으로 논이라는 영농형태가 존재하는 우리나라에서 토양의 수리적 특성해석을 위한 VGM 모형의 적용성에 한계가 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.89-92
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• 2015

In this paper, we propose a method to reduce the fire suppression time. Our suggestions can secure a safe area according to the diffusion path and speed of the fire, forest fire prediction minimize casualties and property damage forests. The existing path prediction method wildfire spread predict the wildfire spread model and speed through topography, weather, fuel factor and the image information. In this case, however, occur to control a large mountain huge costs. Also Focus on the diffusion model predictions and the path identified by the problem arises that insufficient efforts to ensure the safe area. In this paper, we estimate the moving direction and speed of fire at a lower cost, and proposes an algorithm to ensure the safety zone for fire suppression. The proposed algorithm is a technique to analyze the attribute information that temperature, wind, smoke measured over time. According to our algorithm forecast wildfire moving direction and ensure the safety zone. By analyzing the moving speed and the moving direction of the simulated fire in a given environment is expected to be able to quickly reduce the damage to the forest fire fighters.

• Journal of the Institute of Electronics Engineers of Korea CI
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• 제38권2호
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• pp.1-8
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• 2001

In this paper, we propose an algorithm which estimates the displacements and velocities of objects in the soccer field from the soccer image sequences. Assuming the time interval of an object movement is given, we transform the object positions into those in the soccer field model and compute the distance and the velocity. When four corresponding pairs of the feature points, such as the crossing points of the lines in the soccer field, exist and three of them are not on a line, we transform the object positions in the soccer image into those in the soccer field by using the perspective displacement field model. In addition, when the soccer image has less than four feature points, we first transform the object positions into those in the image which has more than four feature points, and then transform the positions into those in the soccer field again. To find the coordinate transformation between two images, we estimate the panning and zooming for consecutive images in the sequence. In the experimental results, we quantitatively evaluated the estimation accuracy by applying our algorithm to the synthetic. soccer image sequences generated by graphic tools, and applied it to the real soccer image sequences for broadcasting to show its usefulness.

• KSBB Journal
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• 제11권5호
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• pp.606-612
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• 1996

A specific ammino auid in a mixture can be crystallized inside an ion exchange column when displacer concentration is high enough to concentrate the amino acid in a pure band beyond its solubility limit. Glutamic acid formpd a discrete crystal layer in a cation exchanger column by operating displacement development mode and using a high concentration of displacer NaOH. The glutamic acid crystal formed was eluded from the column with the effluent stream and collected in a fraction collector. When 1.0 M of NaOH was used as a displacer, more than 60% of the loaded glutamic acid was recovered as crystal. The continuous crystallization and dissolution of crystal occurred, resulting in apparent movement of the crystal along the column without clogging or pressure increase. NaOH was proved a better displacer than NaCl because hydroxide ions neutralized hydrogen ions released from the resin and thus reduced the number of hydrogen ion competing with sodium ion for re-adsorption. The displacement development process coupled with crystallization provided higher concentration and recovery of glutamic acrid than conventional chromatography.

• The KIPS Transactions:PartC
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• 제8C권6호
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• pp.831-838
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• 2001

Mobile information service aims to provide some degree of effective information for real life activities of mobile users. Due to the user mobility and actual realism, it becomes very important technical issue to support an adaptive information service methodology to current situations of the terminal and/or user. This paper deals with a prefetching scheme for location-aware, out of the various context-aware which can be considered in mobile information service. It makes use of the velocity-based mobility model to shape the terminal and/or user's mobility behavior. Based on the moving speed and direction, the prefetching zone is proposed to define the number of prefetched information, so as to limit effectively the prefetched information whilst to preserve the location-aware adaptability. Using a simulator, the proposed scheme has been evaluated in the effectiveness point of view. The idea in this paper is expected to be able to extended to the other mobile service contexts, such as service time, I/O types of mobile terminals, network bandwidth.

• Proceedings of the KIEE Conference
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2233-2235
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• 2003

본 논문에서는 mGA를 이용해 축구로봇의 속도를 제어하는 새로운 방법을 제안하였다. 축구 로봇의 목표를 최소 시간내에 도착하기 위해 속도제어에 크게 영향을 미치는 거리 오차와 각도 오차 등의 비율를 나타내는 각종 파라미터가 포함되어 있는 제어 함수를 제시하고, 이들 파라미터들을 mGA을 이용하여 최적의 값들을 탐색함으로써 변화되는 환경 속에서도 로봇의 목적지에 최소 시간내에 이동하도록 속도제어 전략을 제안한다.

• Korean Chemical Engineering Research
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• 제48권2호
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• pp.157-163
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• 2010

A new etchant formulation was developed in this study to increase the shadow mask production rate, utilizing the $Fe(ClO_4)_3$ as an additive in the aqueous $FeCl_3$ solution. The shadow mask etch rate increased substantially with the increase of $Fe(ClO_4)_3$ concentration in the etchant. The etch rate difference between Ni and Invar steel was also reduced with the addition of $Fe{(ClO_4)_3}$ for most of the operating conditions, which was caused by the enhanced etch rate of both Ni and Fe by the new etchant. The increase in etch rate with the addition of $Fe(ClO_4)_3$ to aqueous ferric chloride solution was attributed to the superior electron transfer capability of $ClO^{4-}$ ion to that of $Cl^-$ ion.

• Journal of the Korean Chemical Society
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• 제28권1호
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• pp.26-33
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• 1984

The rate constants for the following vibration-to-vibration energy exchange reactions have been calculated theoretically for the temperature range from 300 to 800K and for n = 2 to 5. HF(v=n) + DF(v=0) ${\to}$ HF(v=n-l) + DF(v=l) + ${\Delta}E$(a) DF(v=n) + HF(v=0) ${\to}$ DF(v=n-l) + HF(v=l) + ${\Delta}E$(b) In calculation the loosely-held, non-rigid dimer collision model and semiclassical method have been employed. The results show that the rate constants for the processes (a) are much greater than those for the processes (b). Also, it is found that the rate constants for the processes (a) increase with decreasing temperature and with increasing quantum number, while those for the processes (b) show the opposite tendencies. These findings are explained in terms of the sign and magnitude of the energy mismatch, ${\Delta}E$.