• The Korean Journal of Malacology
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• v.18 no.2
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• pp.83-91
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• 2002

Reproductive cycle of natural population and artificial control experiments of gonadal development by the conditions of water temperatures-feeding and starvation of Ruditapes philippinarum were investigated by histological observations. The reproductive cycle of natural population in females and males can be categorized into five successive stages; early active (February to March), late active (April to May), ripe (April to August), partially spawned (May to October), and spent-inactive stage (August to March). In the artificial control experiments, gonadal development of this species was inhibited by the low water temperature (10$^{\circ}C$). In the experimental group which was exposed to artificial high water temperatures of 19$^{\circ}C$ and 22$^{\circ}C$, gonadal development was accelerated by the higher water temperatures and was faster (about one month) than that in natural populations. In the high water temperatures-feeding experimental group, the gonadal developmental phase was faster in the small-size group than that in the large-size group, and was faster in lower water temperature (10$^{\circ}C$)(p=0.01). The gonad developmental phases in the high water temperature (22-28$^{\circ}C$)-starvation experimental group showed faster (paired sample t-test, p=0.004) than those in the high water temperature-feeding group in females and males. In the high water temperature-feeding experimental group of female and male gonadal developments of small sized group were more sensitive than those in large sized group after 42 days cultivation, However, the gonadal development of male was more sensitive to the lower water temperature than female. On the whole, sexual maturation in the high water temperature experimental group was faster than those in the low water temperature group, and showed a significant difference (paired sample t-test, p=0.001) between female and male. In the starvation experimental group after 42 days, gonadal developments in the high water temperature-large male group showed faster than those in the high water temperature-large female group. However, in small size, gonad developmental phases showed the same pattern between feeding and starvation experimental groups. During the main spawning season, in the high water temperature-starvation experimental groups in females and males, their gonadal development showed faster than that in higher water temperature-feeding experimental group regardless of their sexes and individual sizes and showed a significant difference (paired sample t-test, p=0.004).

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.93-99
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• 2015

The purpose of this study was to determine the appropriate temperature for water curtain in greenhouses equipped with recirculated water curtain system. The study analyzed the changes in air temperature in non-heated greenhouses for strawberry cultivation based on outdoor temperature, water curtain temperature and night time. Three greenhouse units were used for this study: The first unit was assigned as a control (no water curtain system), two other greenhouses were equipped with recirculated water curtain system with water curtain temperatures of $10^{\circ}C$ and $15^{\circ}C$, respectively. Analysis showed that the indoor temperatures were directly correlated with the outdoor temperature in all experimental greenhouses. Heat insulating effect of $15^{\circ}C$ water curtain was increased by $1.3^{\circ}C$ compared to that in $10^{\circ}C$ water curtain system. The $15^{\circ}C$ water curtain treatment showed the highest average temperature and less temperature variation in comparison with control and $10^{\circ}C$ water curtain treatment. To maintain indoor temperature at $5^{\circ}C$, water curtain temperature of $10^{\circ}C$ was suitable when outdoor minimum and average temperatures were -1.3 and $1.5^{\circ}C$, and water curtain temperature of $15^{\circ}C$ was suitable when outdoor minimum and average temperatures were -4.7 and $-0.2^{\circ}C$, respectively. The highest temperature in greenhouses according to measurements in different periods of night time was observed after sunset (18:30-20:30), and the lowest temperature before sunrise (05:00-07:00). Water curtain maintained a target indoor temperature by acting as a layer of heat transfer insulator which decreased heat loss from greenhouses. Therefore, water temperature in recirculating water curtain systems should be determined by considering outdoor temperatures, changes in temperature at different periods of night time, and cultivated crop.

• Journal of Korea Water Resources Association
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• v.56 no.6
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• pp.419-429
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• 2023

The objective of this study was to determine the management water level of an estuary reservoir considering three aspects: the water use, flood control and water quality, and to use a robust decision-making to consider uncertainty due to climate change. The watershed-reservoir linkage model was used to simulate changes in inflow due to climate change, and changes in reservoir water level and water quality. Five management level alternatives ranging from -1.7 El.m to 0.2 El.m were evaluated under the SSP1, 2, 3, and 5 scenariosof the ACCESS-CM2 Global Climate Model. Performance indicators based on period-reliability were calculated for robust decision-making considering the three aspects, and regret was used as a decision indicator to identify the alternatives with the minimum maximum regret. Flood control failure increased as the management level increased, while the probability of water use failure increased as the management level decreased. The highest number of failures occurred under the SSP5 scenario. In the water quality sector, the change in water quality was relatively small with an increase in the management level due to the increase in reservoir volume. Conversely, a decrease in the management level resulted in a more significant change in water quality. In the study area, the estuary reservoir was found to be problematic when the change in water quality was small, resulting in more failures.

• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.111-118
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• 2003

This paper proposes a two dimensional behavior analysis method for fish in a water tank based on the ARX method and the Kalman filter algorithm using image processing technology. In modeling the behavior of fish, the input is denoted as the environmental change and uses M-sequence. The output is expressed by the partnership between fish. The behavior model of individual fish is identified by the ARX method. It is then estimated by the Kalman filter algorithm. Finally, the fish behavior is analyzed by FFT. To prove the effectiveness of the pro-posed algorithm, it is applied to two tilapias in a water tank with dimensions of 100cm$\times$100cm$\times$50cm. The effectiveness of the proposed method is demonstrated through ARX identification, estimation of Kalman filter, and FFT analysis.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.94-97
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• 2007

This study aims to find the characteristics of damage and states of natural disasters at Gimhae, Gyeongsangnam-do from 1985 to 2004. Using the data of Statistical yearbook of calamities issued by the National Emergency Management Agency and Annual Climatological Report issued by the Korea Meteorological Administration. we have analyzed the cause, elements, and vulnerable regions for natural disasters. Major causes of natural disaster at Gimhae are four, such as a heavy rain, heavy rain typhoon, typhoon, storm snow, and storm. The cause of disaster recorded the most amount of damage is typhoon. The areas of Hallim-myeon, Sangdong-myeon, and Saengnim-myeon are classified the vulnerable region for the natural disasters in Gimhae. Therefore, it seems necessary to build natural disaster mitigation plan each cause of disaster to control water resources and to reduce damage for these areas.

• Journal of Life Science
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• v.10 no.5
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• pp.467-474
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• 2000

Male mice (ddY strain) were fed a laboratory chow diet containing the water extract from stem bark of Rhus verniciflua Stokes (RVS) for 14 days. There were no significant difference in body weight gain, feed intake, the hepatic lipid profile and serum total cholesterol and phodpholipid concentrations. The concentration of triglyceride in serum was significantly lower in the RVS group than that in the control group. The concentration of high-density-lipoprotein cholestrol in serum was significantly higher in the RVS group than that in the control group. The methanol extract from RVS stem bark effectively inhibited the formation of thiobarbituric acid-reactive substances as a marker of lipid peroxidation of liver microsomes in a concentration-dependent manner. This study showed that the water extract from stem bark of RVS decreased the serum triglyceride concentration and methanol extract has an antioxidative activity.

• Korean journal of food and cookery science
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• v.18 no.5
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• pp.543-547
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• 2002

The purpose of this study was to investigate the effect of water extract of Gardenia jasminoides (WEGJ) on the sensory qualities, color value and shelf-life characteristics (pH, total no. of Bacillus and TBA value) of cooked rice. The total color difference(ΔE) was increased when WEGJ was added. The sensory dualities of cooked rice added with WEGJ had no significant difference in color, taste and torture compared with control group. The pH value of cooked rice addeded with 250 ppm and 500 ppm of WEGJ was less declined compared with control group. WEGJ at the concentration of 250 ppm and 500 ppm had an antimicrobial activity and WEGJ at 500ppm showed an antioxidant activity in cooked rice.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.674-678
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• 2007

기술수준의 발달로 인해 건물이 대형화 고층화됨에 따라 높은 양정의 펌프를 사용하고 있으며, 배관계통을 대부분 전자식 밸브를 채택하여 입상급수라인의 수충격 현상이 대두되어 수충격 현상제어를 위한 여러 방법들이 시행되고 있다. 본 연구는 수충격 현상을 제어하는 방법 중 수충격 방지기를 이용하여 입상급수라인의 수충격 현상의 제어를 효과적으로 제어할 수 있었다. 향후 본 연구를 계속 진행 시켜나감에 따라 수충격 현상의 제어에 큰 성과를 거둘수 있을 것으로 판단된다.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.615-621
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• 1996

Experiments were carried out in humans to assess the relationship between viscosity and post-prandial glucose response of soluble fibers. Eight(3 male and 5 female) healthy individuals were tested for their glucose response after taking control meals or 3 test fiber meals of different viscosities. Meal viscosity of the test food was adjusted to be between 200 and 70, 000 cps. There was a significant increase in post-prandial glucose response(p=0.01) in control meals by solely increasing the volume of water. Fiber with the highest viscosity konjac mannan demonstrated the lowest relative glucose response(70.1$\pm$6.6), followed by medium viscosity xanthan (79.3$\pm$8.7)and low viscosity psyllium (86.3$\pm$10.5). The difference is significant at the level of p<0.05. However, no significant difference in relative glucose response of the same fiber was found when the 4 levels of water were added to make different meal viscosity of each fiber (p=0.476). This result suggested that hypoglycemic action of soluble dietary fibers is related to fiber viscosity rather than meal viscosity.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.4
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• pp.45-51
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• 1991

The objective of this paper is to show how the fuzzy sets theory can be applied to the reservoir operation guidelines for agricultural purposes. The concepts of the theory has been resented as a new tool for the decision problems which contains fuzziness and it's application can be found in operations research, expert systems, robotics, fuzzy computers, and pattern recognition. The fuzzy control system for the reservoir operation composed of a set of reservoir operation rules and a fuzzy inference engine was built. Water demand for paddy fields, water availability, and inflow to a reservoir were selected as main factors which determine the magnitude of reservoir release. The behavior of the control system was evaluated for different level of water demand and the results seemed to be reasonable.