• Journal of Korean Port Research
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• v.13 no.1
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• pp.123-132
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• 1999

It is very important to quantitatively assess the movement of sea water and pollutant dispersion before or after constructing shore structures such as breakwater considering marine environment and long-term utilization of those structures. This assesment is possible through the use of simulation models designed to predict water movement and pollutant dispersion in a certain area. In this study the numerical computations were carried out to predict the sea water quality in the Ilgwang Harbor located at the east coast of Pusan. The flow patters were investigated before and after the development of Ilgwang Harbor. The computational models adopting ADI Method (Alternating Direction Implicit Method) were used here and were already verified from the previous studies. As a results of this study the tidal exchange in Ilgwang Harbor after development proved to be worse due to the increased semi-enclosed at the harbor limit. In order to improve the water quality of this area after development a new method was proposed to improve water quality in the semi-enclosed bay by creation and control of tidal residual currents. For this purpose the unsymmetric structures so called bottom roughness were introduced in this study. The simulation was carried out on the basis of the study by Komatsu et. al. and Gug and we made a conclusion that it is possible to generate a new tidal residual current and to increase the tidal exchange by application of bottom roughness arrangement.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.74-75
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• 2003

This study was conducted to investigate the effects of several additives(macroalgae, wasabi, and herb) in formulated diets on the growth, body composition, blood chemistry and non-specific immune response of juvenile flounder. Three replicates of juveniles (average weight 8.4 g) in flow-through aquarium system were fed one of six isonitrogenous (45%) and isolipidic (8%) diets containing 5 and 10% Undaria powder, 2% wasabi leaf, 2% wasabi stem, and 0.5% herb (Obosan) for 8 weeks. Survival was not affected by the different dietary additives (P>0.05). The highest weight gain and feed efficiency offish fed the diet containing 0.5% herb were significantly higher than those of fish fed the diets containing 10% Undaria powder (P<0.05). No significant differences were found in contents of moisture, crude protein, lipid and ash of whole body (P>0.05). Fish fed the diet containing 10% Undaria powder showed the highest moisture and the lowest crude lipid contents in the liver. Although hematological parameters (red blood cell, hematocrit and hemoglobin) and serum constituents (glucose, total cholesterol and glutamic-oxaloacetic transaminase) contents of fish varied between treatments, no specific trend was observed throughout feeding periods. Lysozyme activity in the serum and nitroblue tetrazolium reduction of macrophage in the head kidney from fish fed the diets containing herb was significantly higher than those of fish fed the control diet. The results of this study suggest that herb as an additive in this formulated diet may improve growth and non-specific immune response of juvenile flounder.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.6-13
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• 2002

In this paper, we propose an image processing based method to measure red-time and green-time backward moving shockwave speed automatically at signalized intersections. Shockwave means the discontinuous boundary line between different vehicle traffic flows, and its moving speed is called shockwave speed which is obtain from the slope of boundary line. In this paper, we compose distance-time diagram for measuring shockwave speed automatically. By global vehicle tracking, we draw all of the vehicle moving path on distance-time diagram. We analyze the slope change pattern of curved moving path line, and compute red-time and green-time backward moving shockwave speed. We obtain the measurement result of shockwave speed, when applying above mentioned proposed method to experiment at signalized intersections, Once we can measure the shockwave speed, we could apply the result to highway ramp metering and automatic signal control at intersections effectively since we know the situation of frontal congestion easily.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.843-849
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• 2009

The reliable operation of a swing check valve in the main feed water system of a power plant is most essential for successful shout-down process. A failure to close the valve at proper time often leads to the instability of the main feed water system, or even to an emergency stop of the power plant. In reality it is a very difficult task to monitor the behavior of a swing check valve. Furthermore it is impossible to see the motion of the valve. In this work two measurements were carried out simultaneously to determine the precise valve closure time. The dynamic pressure measurements were made at the inlet and outlet regions of the swing check valve. The transient vibration of the valve housing in the direction of water flow was also measured, which enabled the measurement of the transient vibration of the valve housing near valve closure. By comparing the results produced from these measurements the precise valve closure time could be determined. By carrying out order tracking technique using the dynamic pressure signals and pump rpm signal, the complicated dynamic problems inside the main feed water system can be more easily dealt with. This measurement scheme might be implemented in a power plant on a real-time basis without much difficulty. If this could be implemented, valuable information essential for shut-down operations can readily be passed on to the main control room. The feasibility of this implementation was demonstrated by this experimental work.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1159-1164
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• 2010

Several triterpenoid saponins from root of Pulsatilla koreana Nakai (Ranunculaceae) were studied and their biological activities were reported. It is difficult to analyze triterpenoid saponins using HPLC-UV due to the lack of chromophores. So, evaporative light scattering detection (ELSD) is used as a valuable alternative to UV detection. More recently, a charged aerosol detection (CAD) has been developed to improve the sensitivity and reproducibility of ELSD. In this study, we developed and validated a novel method of high performance liquid chromatography coupled with a charged aerosol detector for the simultaneous determination of four triterpenoid saponins: pulsatilloside E, pulsatilla saponin H, anemoside B4 and cussosaponin C. Analytes were separated by the Supelco Ascentis$^{(R)}$ Express C18 column (4.6 mm ${\times}$ 150 mm, 2.7 ${\mu}m$) with gradient elution of methanol and water at a flow rate of 0.8 mL/min at $30^{\circ}C$. We examined various factors that could affect the sensitivity of the detectors, including various concentrations of additives, the pH of the mobile phase, and the CAD range. Linear calibration curves were obtained within the concentration ranges of 2 - 200 ${\mu}g$/mL for pulsatilloside E, anemoside $B_4$ and cussosaponin C, and 5 - 500 ${\mu}g$/mL for pulsatilla saponin H with correlation coefficient ($R^2$) greater than 0.995. The limit of detection (LOD) and quantification (LOQ) were 0.04 - 0.2 and 2 - 5 ${\mu}g$/mL, respectively. The validity of the developed HPLC-CAD method was confirmed by satisfactory values of linearity, intra- and inter-day accuracy and precision. This method could be successfully applied to quality evaluation, quality control and monitoring of Pulsatilla koreana.

• The Korean Journal of Physiology
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• v.23 no.2
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• pp.377-391
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• 1989

Recently it was suggested that the endogenous adenosine might be the mediator for the intercellular communication in the regulation of tubuloglomerular feedback control and renin release. Even though the previous data showed more important regulatory roles in the renal hemodynamics and renin release for the A1 adenosine receptor, it has not yet been settled down about the functional subclassification of renal adenosine receptors. The purpose of the present experiment was to clarify the importance of the renal adenosine receptors for the regulations of the hemodynamic, excretory and secretory functions. Experiments have been done in unanesthetized rabbits. Intrarenal arterial infusion of A1 adenosine antagonist, 8-phenyltheophylline, $3{\sim}30\;nmole/min$, increased urine flow, renal hemodynamics and urinary excretion of sodium. Intrarenal arterial infusion of Al antagonist, 1-3-diethyl-8-phenylxanthine (DPX), $10{\sim}100\;nmole/min$, increased renal hemodynamics and excretory functions. Non-specific adenosine antagonist, theophylline, $30{\sim}300\;nmole/min$, resulted in dose dependent increases in renal hemodynamics and excretory function. All of the three adenosine antagonists for the increases in renal hemodynamics, excretory and secretory functions was 8-phenyltheophylline > DPX > theophylline. These results suggest that the endogenous adenosine is important for the intrinsic regulatory roles for the renal functions through the adenosine receptors, and that the A1 adenosine receptor is more important than the A2 receptor in the regulation of renal hemodynamics, excretory and renin secretory functions.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.113-121
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• 2013

In this paper, simulations were carried out to determine the efficiency of the rotation efficiency according to the draft of waterwheel in open rectangular channel. In the small hydroelectric generators to get the highest efficiency of waterwheel is very important. But the presence of various elements(free water surface flow, non-uniform velocity distribution because of the waterways wall friction etc) makes it difficult to create a mathematical formula. In this paper, we made a scale model and perform a physical simulation where the draft, gradient and flux is variable. Scale modelling with 10-step draft, 3-step gradients and 2-step flux, as well were constructed then computerized automatic experimental system were configured to acquire the rotational efficiency vs. draft of itself. Rotational efficiency is analyzed as for the draft of waterwheel using the acquired data by varying the gradient and flux of canal. Reviewing the analyzed data, it is confirmed that phenomena of efficiency shown at previous and present experiment is similar and revealed that computerized system shows more sophisticated numerical figures.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.183-190
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• 2013

Many researchers in the 21st century has found that robot education is effective to develop the learners' creativity and problem-solving ability. However, the robot education can only be applied to the students whose computer skills are high. Also it can be taught in the well-prepared computer classroom. Students have to learn machine language to control their robots, and robots are controlled by different types of software. Therefore this study has constructed command-based programming blocks to do a robot programming without computers. It also presents a prototype of the programming process and a technological method to combine the command and the programming blocks. We used the blocks which are similar with something in flow chart: to support intuition, and to help students transfer what they learned. And types of blocks and details are described for the Robot Programing Education. Combination of command blocks is made by RS-485 connection method and, it is designed to intercommunicate with connected blocks. It also presents a prototypes: of the programming process using designed command blocks, and of the possibility of Unplugged Robot Education System.

• Journal of Biosystems Engineering
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• v.10 no.1
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• pp.13-23
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• 1985

Spraying method from the paddy-field levee is known to give insufficient penetration of the spray droplets to the rice stem of the densely grown plants, which is generally encountered at the last stage of rice growth. This study was intended to investigate the spraying system to solve this existing problem. As an approach, it was attempted to develop the boom-with-nozzle, between-the-row application system. Several types of nozzles and their different arrangements in the boom were tested in the field to measure the penetration-reaching distance and the uniformity of spray droplet distribution. The results of the study are summarized as follows: 1. Field experiments by the spraying method from the paddy-field levee showed to have practically no penetration of the spray droplets to the portion of the plant stem with the normal flow volume generally applied and thus need for improving present spraying method. 2. It was found that, considering both the uniformity of the spray droplet distribution and performance rate, the most efficient type of nozzle in the between-the-row boom-type spraying system was one that has core-insert hollow-cone with some clearance between the cone and tip. 3. When tested by applying the spraying method of between-the-row, the nozzle pressure did not affect the uniformity of spray droplet distribution. However, the nozzle pressure had a positive effect on the penetrating-reaching distance of the facing side of the rice stem and did not affect much on that of the opposite face of the stem. It was also found that the maximum pressure to affect the penetration-reaching distance was about $10kg/cm^2$. 4. The uniformity of the spray droplet distribution in the between-the-row system was greatly affected by the height and orientation of the nozzles in the boom. Based on experimental work for the different type of the boom-with-nozzle arrangements, it is recommended that the position of nozzle is set at about 0.45 m above the ground and two nozzles in the boom are oriented to be faced with each other with some angle such that the droplet stream from the nozzle would not directly face with each other.

• Journal of the Korean Geosynthetics Society
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• v.8 no.3
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• pp.35-44
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• 2009

The purpose of this study was to prevent spreading of contaminants from movement of underground water by creating a barrier using artificial freezing method on a soil contaminated by oils and various NAPLs. Specimens with 80% and 90% degrees of saturation were prepared to form freezing barrier using artificial freezing method. With increasing freezing time of freezing barrier, barrier was formed faster in the specimen with 90% degree of saturation by about an hour compared to the specimen with 80% degree of saturation. In addition, thinnest thickness of frozen barrier in both specimens was 50mm after 12 hours of freezing time, showing expansion of freezing area with time. The results of this study can be applied to barrier in waste reclamation sites and contaminated regions or to flow control of contaminants.