• Journal of Environmental Science International
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• v.7 no.4
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• pp.531-540
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• 1998

To examine water pollution status of agricultural water source of greenhouse area in Gyeongnam, the ground water quality was investigated six times at five areas in Gyeongnam from October in 1995 to March in 1996. pH of ground water were generally in the range of 5.9∼7.6. But a site in Changnyeong area was out of the range In 6.0∼8.5 which is water quality standard for agriculture. COD of ground water was below 2.8mg/l. NH4+-N contents in ground water was very low in all areas and the average of NO3'-N contents in Changnyeong and Chinju area was high with 13.2 and 11.5mg/l respectively. Hardness, SO42- and EC of ground water In Hmm were higher than any other area. Fe and Mn contents of ground water in Kimhae were higher than any other area with 7.17 and 0.95wt, respectively. Heavy metals such as Cu, Cd, Pb and Zn of ground waker were below water Quality standard far agriculture but some sites were over. Between COD and SS in ground water were not correlated with rInG.338,'but between COD and NH4+, -N were positively correlated. And EC was positively correlated with Ca2+, Mg2+ and SO42-. Ground water pollution status of agricultural water source of greenhouse area in Gyeongnam was genrrally high in order of Sacheon < Chinju < Hmn < Kimhae < Changnyeong.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.361-366
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• 1991

A ground and airborne control system for remotely piloted vehicle (RPV) is described. 1) Ground control system 2) airborne control system 3) the method of measuring aircraft attitude and heading 4) autopilot 5) the method of treating emergency status 6) the method of transmitting and receiving communication data 7) the method of displaying aircraft status 8) the characteristics of the aircraft control system are discussed in some detail.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.577-583
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• 2013

We have analyzed influence of potential rise in negative bus, which caused by decrease of power feeding line insulation, upon protecting method of DC ground protection device which detecting potential rise between negative bus and ground in order to detect ground fault in the rubber wheel system. For this purpose, we proposed negative potential equation between negative bus and ground and calculated negative potential according to system condition changes by estimating power feeding line insulation changes in steel wheel system and rubber wheel system, and equalizing DC power feeding system when ground fault occurred. Also, in order to estimate negative potential of real system, we modeled the rubber wheel system, and simulated normal status, grounding fault occurrence and power feeding line insulation changes. In normal status, negative potential did not rise significantly regardless of vehicle operation. When ground fault occurred, negative potential rose up over 300V regardless of fault resistance. However, we also observed that negative potential rose when power feeding line insulation dropped down under $1M{\Omega}$. In conclusion, our result shows that in case of rubber wheel system unlike steel wheel system, relay will be prevented maloperation and insulation status observation can be ensured when ground over voltage relay will be set 200V ~ 300V.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.325-333
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• 2014

An ADS-B system, which is a critical technology in surveillance area of the CNS/ATM, can replace or compensate a conventional radar based surveillance system through the communications among aircrafts. An ADS-B ground system which is to use the ADS-B on the ground air traffic management system consists of various subsystem devices such as ground stations that communicate with the aircrafts, and ADS-B/TIS-B/FIS-B servers. The ADS-B ground system has a form of distributed system and is interconnected through the network. Therefore, a system which can monitor and control the status of the multiple subsystem devices of the ADS-B ground system is essential. In this paper, we designed and implemented a remote status monitor and control system for the ADS-B system that can monitor and control the subsystem devices of the ADS-B system in remote place via SNMP protocol.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.05a
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• pp.28-44
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• 1993

Remediation actions in uncontrolled landfill site should be conducted after the investigation of contamination status and potential health risk or damage. Based on the above, proper control measures should be established and operated. Also continuous monitoring should be followed. In this study, the status of ground water contamination around Nanji Landfill Site was investigated. Monitoring wells were installed around the landfill and ground water was sampled once a month and analyzed. Water quality of each monitoring well was different depending on the horizontal and vertical distance from the landfill, and the seasonal leachate characteristics were not significantly changed because percolating water stayed long time in the deep waste layer. It was predicted that major multivalent cations were mainly precipitated as metal carbonate form, and chemical mass balances (CMBs) could be applied for the apportionment of leachate contamination to ground water quality of surrounding areas of Nanji Landfill. Parameters required to estimate pollutant flux to the receptor near landfill were listed and discussion to get these parameters was made. Finally, based on the above data, control measures of ground water contamination were suggested and discussed.

• Journal of the Korean Institute of Landscape Architecture
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• v.19 no.3
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• pp.1-15
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• 1991

The current status of evergreen ground-cover plants as of in the winter months in 50 places selected at random in Seoul was assessed to see how they are at the present, and the following matters of evergreen ground-cover plants were observed to be common aspect of them today during the year of 1989 and 1990 and in winter of Seoul. 1. Ground-cover area in 50 different places of Seoul was 36% of the green area, and the evergreen ground-cover area was 3% of total ground-cover area. As the result, most of ground cover plants founded to be zoysia grasses. 2. Total number of evergreen ground-cover plants species was 24, and the species most frequently found were Juniperus chinensis and horizontalis, Buxus koreana, Liriope platyphylla var. nana. Taxus cuspidats, Rhododendron lateritium, Pleioblastus pygmaea, Poa pratensis in that order of the number of plasces assessed, and sere Poa pratensis, Agrostis tennuis, Liriope platyphylla, Buxus koreana, Juniperus chinensis and horizontalis, Taxus cuspidata. var. nana, Rhododendron lateritium in the order of area planted. 3. Woody plants included 9 species and occupied 16% in the area, also introduced plants included 14 species and occupied 79% in the area. As introduced evergreen grasses occupied, almost of evergreen ground-cover herbs, planting of evergreen ground-cover herbs and native plants are thought to be desirable. 4. Flowering plants of 16 species were found to be 16% of the total evergreen ground-cover area. 5. The ratio of topographical difference, such as plain versus slope for planting site, was 82 and 18% respectively, and sunny versus shady and intermediate places were 72, 15 and 13% respectively. 6. Although appearance of plants was generally fair, poor and drying plants were assessed 33% for the number of places planted, and 11% for the area. It seems to be necessary to manage those plants to their growth characteristics, and desiable to introduce various plant species adaptable to the winter climate of Seoul and grow for the winter landscaping purpose. 7. The poor use and lack of evergreen ground-cover plants are regarded to be deficient in the valus and reconization of them, particularly in the landscaping works. It is therefore considered important to bring out pertinent measures against these inadequate situations.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.736-746
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• 2011

This study aims tried to present develop a management plan for about old and big trees and legally protected trees by investigating through the present the current status and the distribution of the legally protected trees and old and big tree that range in Gwangju, South Korea. The number of legally protected plants that distributed in Gwangju City is 68 individual trees from 9 species. The largest number was found in Gwangsan-gu (18 trees). The total number of the old and big trees that are distributed in Gwangju City was confirmed as 155 individual trees from 10 species. It must to be corrected to a correct plant species name that species name is written in review articles incorrectly. The average vitality rate of the legally protected plants was 1.2 and the status of ground was 1.7 on average. And the vitality rate of the old and big trees was 1.3 and the status of ground was 2.0 on average. Vitality are not significantly different between the legally protected trees and old and big trees. Ground status of old and big trees worse than legally protected trees. Gingko biloba (found in Gwangsan-gu Songdaedong Daechon village) was only legally protected plant that requires urgent management due to low vitality rate (between 3.2 and 4.0). Among old and big trees Salix glandulosa which is found in Gwangsan-gu Sansu-dong Gamdong village was only one that requires urgent care. The most important status for the old and big tree is securing minimal space for growth. Therefore, we conclude that the most urgent measure in the management and projection of old and big trees and legally protected plants is removal of asphalt or cement above the surface of root system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.4
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• pp.310-316
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• 2022

Giant pacific octopus, Enteroctopus dofleini, is a large mollusk distributed in the East Sea of Korea. In this study, the catch status of giant pacific octopus by drift line fishery and the effect of sea temperature on fishing ground were investigated in Goseong-gun, Gangwon-do, which is the central coast of the East Sea. The average catch of giant pacific octopus in Gangwon-do was 1,570 tons over the past ten years, and it accounted for 21% in 2008 and 44% in 2021 compared to the total catch in the East Sea during the same period. Such data indicates that the catch in Gangwon-do has recently increased. In this study area, giant pacific octopus weighing 1.1-5.0 kg dominated accounting for 56% of the total individuals, and followed by those weighing 1 kg or less. However, the ratio of catch of giant pacific octopus over 5.1 kg tended to increase in 2021, which is thought to be related to the sea temperature that affected the fishing ground. The main depth of fishing ground was from 21 m to 50 m in this area and fishing grounds were widely distributed throughout the season except summer. Fishing ground was formed with the conditions of bottom sea temperature under 10℃ and was diminished by moving of giant pacific octopus to deeper depth with conditions of bottom sea temperature over 18℃.

• Land and Housing Review
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• v.8 no.1
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• pp.13-22
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• 2017

In this study, triggering mechanism of ground sinking was analyzed through groundwater flow analysis on the basis of a case of the ground sinking occurred in Yongsan in 2015. The results of geotechnical investigation performed before and after the ground sinking were analyzed for the accurate understanding of geological features in the study area. The numerical groundwater flow analysis was performed to evaluate the influence of the flow behavior from the surrounding area toward the excavated site using software of Visual MODFLOW. As a result, it was found from the geotechnical analysis that the strata of sedimentary layer along the sunken area in the vertical direction was mixed significantly after the ground sinking compared with the status of the soil condition before the ground sinking. Piping was occurred at the toe of cut-off wall in the sandy gravel layer, and this phenomenon was predicted by the numerical flow analysis. Sequential ground displacement scenario of the ground sinking was derived from the geotechnical in situ test and numerical flow analysis performed in this study.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.12
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• pp.529-535
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• 2006

In DC tracking power supply system, ground faults are currently detected by the potential relay, 64P. Though 64P relay detects ground fault, it cannot identify the faulted region which causes long traffic delays and safety problem to passengers. A new ground fault protective relay scheme, ${\Delta}I$ ground fault protective relay, that can identify the faulted region is presented in this paper. In ${\Delta}I$ ground fault protective relaying scheme, ground fault is detected by 59, overvoltage relay, which operates ground switch installed between the negative bus and the ground. It preliminarily chooses the faulted feeder after comparing the current increases among feeders and trips the corresponding feeder breaker. After some time delay, it then recloses the breaker if it finds the preselected feeder is not the actual faulted feeder. Whether or not the preselected feeder is the actual faulted feeder is determined by checking the breaker trip status in the neighboring substation in the direction of the tripped breaker. If the corresponding breaker in the neighboring substation is also tripped, it finally judges the preselected feeder is actually a faulted feeder. Otherwise it recloses the tripped breaker. Its algorithms is presented and verified by EMTP simulation.