• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.22-26
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• 2005

Egg incubation periods of 14 species of plecoptera were examined at $10^{\circ}\;{\sim}\;11^{\circ}C$, $15^{\circ}\;{\sim}\;16^{\circ}C$, $20^{\circ}C$, and $23^{\circ}C$ under dark conditions. The total effective temperature (TET) was calculated by multiplying mean egg incubation days and water temperature of incubation periods. The relation between the TET and the incubation temperature was used to compare the life cycle of respective species. Perlodid species had higher TET values with a positive relation to incubation temperature than those of other species. Perlid species had low TET values in the 14 species with negative to variable relation, and Chloroperlid species showed variable to positive relations to incubation temperature. These results suggest that the relation between the TET and the water temperature reflected on their habitat of respective species.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.27-30
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• 2005

Diel vertical migration (DVM) and horizontal distribution of Chaoborus flavicans larvae were studied in Lake Fukami-ike (maximum depth 7.75 m, Central Japan). The larvae showed a clear migration in the 4 ${\sim}$ 7 m layer during the day and throughout the water column at night. It should be noted that, while old instar distributed throughout the column during the night. Young instar was found only in the 1 ${\sim}$ 4 m layer. An examination of horizontal distribution revealed that larval stage was clearly related with the depth. It suggests that Chaoborus appear to exist in the deeper area during the larval stage.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.17-21
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• 2005

We investigated the diel periodicity in the drift in relation to body size by field survey using the fourth instar grazing larvae of Micrasema quadriloba Martynov (Trichoptera, Brachycentridae) as a material. Although the larvae showed nocturnal drift periodicity, drift density in the nighttime was only twice that in the daytime. In both time periods, smaller individuals drifted significantly more, and the drift individuals in the daytime was the smallest in size (P< 0.05 in Sheffe's F). We discussed whether the drift of the fourth instar larvae drift behaviorally or accidentally considering larval size and food depletion.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.62-66
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• 2005

The distributions of fluorescent whitening agents (FWA) in the water of the Yasu River and their tributaries flowing into Lake Biwa (Japan) were surveyed on winter and summer. The FWA fluxes had linear correlation with the corrected resident population in catchments of the tributaries of Yasu River. Therefore, the FWAs in the rivers come from domestic wastewater, and those fluxes in the tributaries depended on the human population of their catchments. As an application of the FWA indicating domestic wastewater, we could assess seasonal changes in the sources of dissolved organic matter in the tributaries.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.58-61
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• 2005

Environmental polluting materials from road surface drainage are a significant nonpoint source influenced to the eutrophication of lake and ecosystems with a transport development in recent years. To elucidate the discharge characteristics, the changing patterns in concentrations of polluting materials such as suspended solid (SS), chemical oxygen demand (COD), nitrogenous and phosphorus nutrients in drainage waters, were investigated during rainfall. Load variation of COD concentration in drainage water samples was closely related to that of SS concentration. This indicates that SS contained a greater part of organic matter. A quite difference between the past pavement and the new well-drainage pavement system was observed in the concentrations of SS and COD in drainage waters. Appreciable concentrations of nitrite and nitrate were determined in drainage waters. The present results indicate that the drainage water from road surfaces is a significant nonpoint source, and that the well-drainage pavement system introduced to skid prevention has an effect on the decreases of pollutants.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.76-83
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• 2005

The marked increase in the number of environmental problems, combined with the increase in their intensity and spatial extent, has resulted in an ever-increasing need for constant monitoring. This is complicated by the occurrence of new and complicated environmental issues that often prevent a thorough understanding of the entire monitoring framework. In the present study, a diagrammatic method was developed to present the entire framework of a monitoring plan. The diagram was separated into three sections- "Problem Section", "Research Process and Data Section" and "Entities Section" - to clearly present the disparate relationships between monitoring objectives and the monitoring procedure. Notation of the diagrams was undertaken using Unified Modeling Language (UML). A hypothetical monitoring plan for an environmental problem was designed to assess usefulness of the diagrammatic method. The diagram was capable of reviewing and revising the monitoring plan and could be used to select a monitoring procedure according to the monitoring objectives of the plan. The results suggested that this diagrammatic method was effective for designing an appropriate monitoring plan for a given monitoring objective.

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.128-132
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• 1998

In this study, water quality characteristics of lakes in the Seosan area are analyzed. Components water quality were analysed at 10 sampled points in each lakes, and the results were evaluated for seasonal variation. It was found that water quality was over II~III class. Most of lakes in the Seosan area which implies that are suitable as the maintenance water. The concenturation of T-N, T-P was observed IV~V class during all seasons. Particularly, T-N concenturation peaks in spring, while was lowered in other seasons. In the lake, high concenturation of T-N, T-P bring about Eutrophication when algae was growth causing various physico-chemical changes in the water. It is suggested that the water quality management strategies need to be applied for each lake.

• Animal Systematics, Evolution and Diversity
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• v.7 no.2
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• pp.241-256
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• 1991

The systematic study of freshwater rotifers was conducted on the materials collected from 197 sites in South Korea. As a result, 9 species of Family Colurellidae were identified, 4 species ( 1 species and 3 subspeices) of which are new to the Korea fauna ; Courella uncinata uncinata, Squatinella rostrum rostrum, Lepadella patella patella, and L.elliptica. Total 165 species representing 13 families and 40 genera are now recorded by addign the species described in the present paper.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.318-323
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• 1990

The bacterial secondary production was measured at 6 sites of Lake Soyang in October, 1989 by $^{3}$H-thymidine incorporation rate. Verfication for the method of bacterial secondary production measurement showed that $^{3}$H-thymidine incorporated into DNA, RNA and protein by average percentage of 38.45, 42.27 and 20.07%, respectively. THe more increased incoporated $^{3}$H-thymidine, the more increasde DNA fraction, but protein fraction was generally low. Incorporation of rate of /usp 3/H-thymidine. $^{3}$H-leucine into protein correlated with protein fraction of incorporated $^{3}$H-thymidine. Conversion factors were calculated as follows; $1.83*10 ^{20}$ cells/moles of thymidine incorporated/hr and 1.69*10$^{22}$ cells/moles of leucine incorporated/hr.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.130-136
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• 2001

This paper presents an of a brake pressure restriction valve to a motorcycle anti-lock brake system(ABS). In the conventional anti-lock brake system of automobiles, slip ratio as a control variable is actively controlled, which requires wheel speed sensors, ECU, and a pressure modulator. In the ABS valve that has been developed for use in motorcycles, however, the brake pressure that is close to the wheel locking pressure is preset by simple exercises and then the valve just allows to pass the wheel locking pressure and cutoff the remaining pressure. Simulation studies with a single wheel braking dynamics and lumped chassis model show that the pressure restriction valve has basic ABS functions as well as some robustness properties for the uncertain load and road conditions as well as various initial braking speeds. Field tests also show that the pressure restriction valve avoids the wheel locking effectively.