• 한국환경과학회지
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• 제7권4호
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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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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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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.

• 전기학회논문지
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• 제62권4호
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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.

• 한국항행학회논문지
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• 제18권4호
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• pp.325-333
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• 2014

CNS/ATM을 구성하는 감시 시스템의 핵심 기술인 ADS-B는 항공기와 항공기 간의 정보 교환을 통해 기존의 레이더 감시 시스템을 보완 및 대체할 수 있다. ADS-B를 지상 항공 교통 관리 시스템에서 사용할 수 있도록 구축하는 지상 ADS-B 시스템은 항공기와 ADS-B 메시지를 송수신하는 지상장비, ADS-B/TIS-B/FIS-B 서버 등 다양한 장비가 필요하며 이들 장비는 네트워크 기반의 분산 시스템 형태로 구성된다. 따라서 지상 ADS-B 시스템의 분산된 장비들을 효율적으로 관리할 수 있도록 원격에서 지상 ADS-B 시스템을 구성하는 장비들의 상태를 감시하고 제어 할 수 있는 상태 감시 및 원격 제어 시스템이 반드시 필요하다. 본 논문에서는 네트워크 기반 상태 관리 프로토콜인 SNMP를 이용하여 지상 ADS-B 시스템을 구성하는 모든 장비의 상태를 감시하고 제어할 수 있는 ADS-B 시스템 상태 감시 및 원격 제어 시스템을 설계하고 구현하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 지반.환경 매립에 관한 학술발표회 논문집
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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.

• 한국조경학회지
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• 제19권3호
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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.

• 한국환경생태학회지
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• 제25권5호
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• pp.736-746
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• 2011

본 연구는 광주광역시에 분포하는 보호수 및 노거수의 분포 및 생육현황을 조사하여 보호수와 노거수 관리방안을 제시하고자 시도하였다. 광주광역시에 분포하는 보호수는 9종 68개체로 이 중 광산구가 18개체로 가장 많았으며, 노거수는 10종 155개체로 확인되었다. 기존문헌에 잘못 기록된 종명은 정확한 식물명으로 수정되어야 한다. 보호수의 활력도 평균은 1.2였으며 지면상태 평균은 1.7이었고 노거수의 활력도 평균은 1.3, 지면상태 평균은 2.0으로 활력도는 큰 차이가 없었고 지면 상태는 노거수가 조금 더 좋지 못한 것으로 나타났다. 활력도가 3.2~4.0범위를 보여 절대관리가 필요한 보호수는 광산구 송대동 대촌마을 은행나무 1개체 이었고, 노거수는 광산구 산수동 감동마을의 왕버들 1개체로 나타났다. 보호수 및 노거수의 관리방안에서 제일 중요한 것은 기본적으로 노거수가 자랄 수 있는 최소한의 생육공간을 확보하는 것으로 보호수와 노거수 근계 위의 아스팔트나 시멘트 포장을 제거해 주어야 한다고 판단된다.

• 수산해양기술연구
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• 제58권4호
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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℃.

• 토지주택연구
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• 제8권1호
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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.

• 대한전기학회논문지:전력기술부문A
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• 제55권12호
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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.