• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.916-919
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• 1996

An real-time active beacon localization system for mobile robots is developed and implemented. This system permits the estimation of robot positions when detecting light sources by PSD(Position Sensitive Detector) sensor which are placed sparsely over the robot's work space as beacons(or landmarks). An LSE(Least Square Estimation) method is introduced to calibrate the internal parameters of a model for the beacon and robot position. The proposed system has two operational modes of position estimation. One is the initial position calculation by the detection of two or more light sources positions of which are known. The other is the continuous position compensation that calculates the position and heading of the robot using the IEKF(Iterated Extended Kalman Filter) applied to the beacon and dead-reckoning data. Practical experiments show that the estimated position obtained by this system is precise enough to be useful for the navigation of robots.

• ALGAE
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• v.27 no.1
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• pp.63-70
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• 2012

Algae are sensitive to a wide range of pollutants, and are effective bioindicators in ecotoxicity assessments. Here, we evaluated the sub-lethal sensitivity of the marine dinoflagellate Cochlodinium polykrikoides upon exposure to copper (Cu), lead (Pb), bisphenol A (BPA), and Aroclor 1016 (polychlorinated biphenyl, PCB). Toxic effects were assessed by observations of the reduction in cell counts and chlorophyll a levels after exposure to each toxicant. C. polykrikoides displayed dose-dependent, sigmoidal responses when exposed to the tested chemicals. $EC_{50}$-72 h values for Cu, Pb, BPA, and PCB were 12.74, 46.70, 68.15, and $1.07mg\;L^{-1}$, respectively. PCB, which is an endocrine-disrupting chemical, was the most sensitive, proving its toxic effect on the dinoflagellate. This study provides baseline data on the toxic effects of commonly used heavy metals and endocrine-disrupting chemicals to a marine dinoflagellate.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.7
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• pp.987-993
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• 2009

An experimental study is performed to investigate unsteady mixed convection in a horizontal channel with a heat source. Particle image velocimetry (PIV) with thermo-sensitive liquid crystal (TLC) tracers is used for visualization and analysis. This method allows simultaneous measurement of velocity and temperature fields at a given instant of time. Quantitative data of the temperature and velocity are obtained by applying the color-image processing to a visualized image, and neural network is applied to the color-to-temperature calibration. It is found that the periodic flow of mixed convection in a cavity appears at very low Reynolds numbers (Re<0.4), and the period decreases with increasing Reynolds numbers and increases with increasing aspect ratio.

• Journal of Power System Engineering
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• v.20 no.6
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• pp.51-57
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• 2016

Experiment is carried out to investigate the mixed convective flow in three-dimensional horizontal rectangular channels filled with high viscous fluid. The particle image velocimetry(PIV) with thermo-sensitive liquid crystal tracers is used for visualizing and analysis. Quantitative data of temperature and velocity are obtained by applying the color-image processing to a visualized image, and neural network is applied to the color-to-temperature calibration. In this study, the fluid used is silicon oil(Pr=909), the aspect ratio(channel width to heigh) is 4 and Reynolds number is $2{\times}10^{-2}$. From the present study, we can visualize the quantitative temperature and velocity of mixed convective flow in three-dimensional horizontal rectangular channels simultaneously.

• Journal of Environmental Health Sciences
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• v.5 no.1
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• pp.51-57
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• 1978

Antibiotics susceptibilities of Staphylococci were tested to get useful data for prevention food contamination and treatment of food poisoning. Tested were colony counts, isolation of Staphylococci, identification for the Staphylococcus aureus and resistant patterns to antimcrobial agents. The colonies and Staphylococci isolated from the atmosphere of 37 home kitchens in the morning (07:00-08:00) on Nov. 19, 1977 in Busan. The findings are as follows: 1. The average of colony counts was shown to be 9.6 ranging from 47 to 1 at mean temperature of 18$\circ$C (the highest 21$\circ$C, the lowest 15$\circ$C) 2. Out of total 37 kitchens, 18 Staphylococci were isolated from 15 kitchens with 40.5 per cent, and 4 Staphylococcus aureus were identified with 22.2 per cent from 18 Staphylococci. 3. Isolated Staphylococci were resistant to penicillin(100%), dihydrostreptomycin(93.3%), tetracycline (93.3%) and oleandomycin(66.6%), while the strains were sensitive to sulfonamide(88.6%) and colistin(83.3%). 4. Staphylococcus aureus identified were resistant to dihydrostreptomycin, penicillin and tetracycline, while the strains were sensitive to sulfonamide and colistin.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1879-1886
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• 2001

n a enclosed square cavity occurred B nard convection, the flow phenomena in the surrounding of the bubble attached at the upper cooled solid wall were studied by using a thermo-sensitive liquid-crystal tracer and image processing techniques. This method offers the advantage of measuring the entire flow field in a selected plane within the fluid at a given instant of time in contrast to point by point method like T/C. Quantitative data of the temperature were obtained by applying a colour-image-processing to the visualized image. As the flowing in a bubble, In a bubble size appears the flow phenomena which the direction of flow is reversed in the entire temperature and flow field. The observed phenomena are described with regard to the thermocapillary convection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2249-2257
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• 1998

In this paper, we propose the enhanced priority control algorithm that adaptively controls the cell service ratio according to the relative cell occupancy ratio of buffer. The asynchronous transfer mode (ATM) provides the means to support various multimedia services in broadband networks. To support multimedia services, various data traffics of different priorities should be controlled effectively. And also it needs congestion control functions required in the netowrk to carry out the control operation. To accomplish this in a flexible and effective manner, priority classes for the different services ar ecommonly used. The proposed enhanced priority control mechanism have two service calsses of the delay sensitive class and the loss sensitive class. The simulation results show that te proposed control mechanism improves the QoS, the charateristics of cell loss probability and mean cell delay time, by selecting propeor relativ ecell occupancy ratio of buffer and the average arrival rate.

• International Journal of Internet, Broadcasting and Communication
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• v.6 no.1
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• pp.16-22
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• 2014

Clustering methods such as k-means and EM are the group of classification and pattern recognition, which are used in management science and literature search widely. In this paper, k-means and EM algorithm are compared the performance using by Weka. The winning Lottery numbers of 567 cases are experimented for our study and presentation. Processing speed of the k-means algorithm is superior to the EM algorithm, which is about 0.08 seconds faster than the other. As the result it is summerized that EM algorithm is better than K-means algorithm with comparison of accuracy, precision and recall. While K-means is known to be sensitive to the distribution of data, EM algorithm is probability sensitive for clustering.

• Fashion & Textile Research Journal
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• v.13 no.3
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• pp.364-372
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• 2011

The primary purposes of this study were to classify consumer's type according to narcissistic orientation of consumer and then to reveal consumer's perception differences on consumption value of apparel products and cosmetics subject to the types. Data were collected from 194 female college students in Ulsan. It was analyzed by frequency analysis, factor analysis, cluster analysis and MANOVA, ANOVA using SPSS Win 12.0. The results were as follows: First, consumer's types classified according to narcissistic orientation were non-narcissist, high-narcissist, leadership and self-absorption. Second, in the consumption value of apparel products case, there were significant differences in effective value, symbolic value and sensitive value among the types. Third, in the consumption value of cosmetics case, there were significant differences in sensitive value and effective value among the types.

• Advances in environmental research
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• v.1 no.1
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• pp.57-68
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• 2012

Recent studies showed that air pollution is a risk factor for hospitalization for chronic obstructive pulmonary disease (COPD). However, there is limited evidence to suggest which subpopulations are at higher risk from air pollution. This study was undertaken to examine the modifying effect of specific secondary diagnosis (including hypertension, diabetes, pneumonia, congestive heart failure) on the relationship between hospital admissions for COPD and ambient air pollutants concentrations. Hospital admissions for COPD and ambient air pollution data for Taipei were obtained for the period from 1999-2009. The relative risk of hospital admissions for COPD was estimated using a case-crossover approach. None of the secondary diagnosis we examined showed much evidence of effect modification.