• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.312-316
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• 2004

Single-well tracer tests, especially push pull tracer tests, are more effective to estimate hydraulic parameters and microbial metabolic activities in terms of duration and cost compared to multi-well tracer tests. However, there are some drawbacks in accuracy, complicated data analysis and uniqueness. These shortages are thought to be derived from the applied conditions which affect mass recovery curve and breakthrough curve. Factors such as extraction rate, resting period, hydraulic conductivity and hydraulic gradient are considered as the major factors determining the mass recovery rate and shape of the breakthrough curve. The results of the sensitivity analysis are summarized as follows: 1) the significant change in concentration of breakthrough curve is obtained when the extraction rate increases. This effect would also be much higher if the hydraulic conductivity is lower; 2) the mass recovery rate decreases with the increase of resting time, and the difference of mass recovery rates for different resting times is inversely proportional to the hydraulic conductivity; 3) the sensitivity values decrease with time. The hydraulic conductivity affects not only the early period, but the later period of the breakthrough curves; 4) The influence of the hydraulic gradient on the breakthrough curves is greater at earlier stage than at later stage. The mass recovery rate is inversely proportional to the hydraulic gradient.

• Proceedings of the KSRS Conference
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• v.2
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• pp.610-614
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• 2006

In this paper the advanced method of geodesic active contours was developed for the task of building detection from aerial and satellite images. Automatic extraction of man-made structures including buildings, building blocks or roads from remote sensing data is useful for land use mapping, scene understanding, robotic navigation, image retrieval, surveillance, emergency management procedures, cadastral etc. A level set method based on a region-driven segmentation model was implemented with which building boundaries were detected, through this curve propagation technique. The essence of this approach is to optimize the position and the geometric form of the curve by measuring information along that curve, and within the regions that compose the image partition. To this end, one can consider uniform intensities inside objects and the background. Thus, given an initial position of the curve, one can determine global, region-driven functions and provide a statistical description of the inside and outside object area. The calculus of variations and a gradient descent method was used to optimize the variational functional by an iterative steady state process. Experimental results demonstrate the potential of the proposed processing scheme.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.227-230
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• 2004

Two extraction techniques, Ultrasonic and Microwave extraction method, were tested for the determination of arsenic in contaminated soil SRM (Montana Soil). The extraction mixture was prepared by mixing 1 M ortho-phosphoric acid and 0.1 M ascorbic acid. This extractant was known to preserve arsenic species. The appropriate extraction time was 10 min to 20 min and the recovery rate was about 80%. A coupled system, SPE-HG-ICP-AES, was used for the determination of inorganic arsenic species. The detection limit was around 2 $\mu\textrm{g}$/1 and the linearity of calibration curve was better than $R^2$=0.99.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.9
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• pp.77-83
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• 1997

Based on the curve segment grouping, an efficient recognition of round objects form partially occuluded round boundaries is proposed. Curve segments are extracted from an image using a criterion based on the intra-segment curvature and local contrast. During the curve segment extraction the boundaries of pratially occluding and occuluded objects are segmented to different curve segments. The extracted segments of constant intra-segment curvature are grouped to different curve segments. The extracted segments of constant intra-segment curvature are grouped nto a round boundary by the proposed grouping algorithm using inter-segment curvature which gives the relatinships among the curve segments of the same round boundary. The 1st and the 2nd order moments are used for the parameter estimation of the best fitted ellipse with round boundary, and then recognition is perfomed based on the estimated parameters. The proposed scheme processes in segment unit and is more efficient in computational complexity and memory requirements those that of the conventional scheme which processed in pixel units. Experimental results show that the proposed technique is very efficient in recognizing the round object sfrom the real images with apples and pumpkins.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.372-378
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• 2009

With the increase in capacity of photovoltaic generation systems, studies are being actively conducted to improve system efficiency. In order to develop the high performance photovoltaic power system it is required to understand the physical characteristics of the solar cell. However, solar cell models have a non-linear form with many parameters entangled and conventional methods suggested to extract the parameters of the solar cell model require some kind of assumptions, which accompanies the calculation errors, thereby lowering the accuracy of the model. Therefore, in this paper a novel method is proposed to calculate the ideality factor and reverse saturation current of the solar cell from the I-V curve measured and announced by solar cell manufacturers, derive the ideal I-V curve, and then extract the series and shunt resistances value from the difference between the ideal and measured I-V curve. Also, validity of the proposed method is demonstrated by calculating the correlation between I-V curve based on modeling parameters and I-V curve actually measured through least squares method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.23-28
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• 1985

The extraction rate of lipids from the chopped whole fish was studied with various solvents. Factors which can influence on the extraction rate such as temperature, moisture content, agitation speed and solvent were also examined. In the early stage of extraction, it is considered that the rapid extraction was attributed to cell destruction which occurs in chopping the whole fish and in the later stage, the extraction rate was increased linearly with extraction time. The effect of agitation on the extraction rate had a great influence on the early stage of extraction. In agitation speed of 100, 200, 300 and 500 r.p.m. the slopes of extraction curve were -0.075, -0.075, -0.069 and -0.064, respectively. Extractability between hydrophilic and hydrophobic solvent showed a great difference. It is suggested that extractability difference between acetone and isopropyl alcohol is due to acetone property which can not extract phospholipids in polar lipids. Extractability of lipids was increased with increasing temperature and decreased with increasing moisture content.

• Journal of Mushroom
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• v.12 no.4
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• pp.299-303
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• 2014

This study was to comparative analysis that different methods of extraction about total sugar content which the major functional components of edible and medicinal mushrooms. Through the phenol-sulfuric acid method was measured that Hot water extraction, acid extraction, and alkaline extraction. Drawing the standard curve to obtain the concentration of the glucose solution and the sample by applying the measured absorbance on the standard curve. Total sugar contents was measured after extraction with different solvents.(Hot water, 70% EtOH, 80% MeOH). The level of total sugar in Cordyceps militaris is highest in the hot water extraction with 658.4(${\mu}g/g$) and Coriolus versicolor in 649.7(${\mu}g/g$) and 679.0(${\mu}g/g$) was found as the highest in the acid extraction and the alkaline extraction. C. militaris and ASI 7025 showed the highest level in the hot water extraction. Finally, C. versicolor, Sparassis crispa showed that higher than the other mushrooms at the 1hr, 2hr microwave extraction. It was varied total sugar content according to the different extraction solvent and the extraction method.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2809-2815
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• 1999

Level set, and active contour(snakes) models are extensively used for image segmentation or shape extraction in computer vision. Snakes utilize the energy minimization concepts, and level set is based on the curve evolution in order to extract contours from image data. In general, these two models have their own drawbacks. For instance, snake acts pooly unless it is placed close to the wanted shape boundary, and it has difficult problem when image has multiple objects to be extracted. But, level set method is free of initial curve position problem, and has ability to handle topology of multiple objects. Nevertheless, level set method requires much more calculation time compared to snake model. In this paper, we use good points of two described models and also apply multi resolution algorithm in order to speed up the process without decreasing the performance of the shape extraction.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.3
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• pp.265-275
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• 2015

This paper describes extraction methods of five different types of geometrical features (line, arc, corner, polynomial curve, NURBS curve) from the obtained raw data by using a two-dimensional laser range finder (LRF). Natural features with their covariance matrices play a key role in the realization of feature-based simultaneous localization and mapping (SLAM), which can be used to represent the environment and correct the pose of mobile robot. The covariance matrices of these geometrical features are derived in detail based on the raw sensor data and the uncertainty of LRF. Several comparison are made and discussed to highlight the advantages and drawbacks of each type of geometrical feature. Finally, the extracted features from raw sensor data obtained by using a LRF in an indoor environment are used to validate the proposed extraction methods.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.4
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• pp.17-22
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• 2002

This paper used an active contour model which was based on level set algorithms and bidirectional curve evolution theory in order to track the shape of the heart acting continuously. Most active contour models would be failed in boundary extraction because of their unstable movement in the edge gap locations. In this paper, we suggest a new active contour model using only image intensity value and additional constraint needed for stable extraction. Our model was successfully run on either shape extraction or object tracking without any position constraints of initial curve. Also demonstrated stable movements and showed good results at weak or missing boundary locations.