• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3B
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• pp.221-230
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• 2009

In Korea, many water intake plants are easily affected by effluents of sewage treatment plants because sewage treatment plants are usually located upstream or nearby the plants of the same riverine area. Furthermore, the inflow of harmful contaminants owing to pollutant spills or transportation accidents of vehicles using the roads and bridges intersecting the river causes significant impact on the management of water intake plants. Paldang lake, the main water intake plants in Korea, is especially exposed to various water pollution accidents, because the drainage basin area is significantly large compared to the water surface area of the lake. Therefore it is necessary to predict the possible pollutant spill in advance and consider measurements in case of water pollution. In this study, water quality prediction was performed in Paldang Lake in Korea durig the dry season using two-dimensional numerical models. In order to represent the cases of pollutant accidents, the difference of pollutant transport patterns with varying injection points was analyzed. Numerical simulations for hydrodynamics of water flow and water quality predictions were performed using RMA-2 and RAM4 respectively. As a result of simulation, the difference of pollutant transport with the injection points was analyzed. As a countermeasure against the pollutant accident, the augmentation of the flow rate is proposed. In comparison with the present state, the rapid dilution and flushing effects on the pollutant cloud could be expected with increase of flow rate. Thus, increase of flow rate can be used for operation of water intake plants in case of pollutant spill accidents.

• Korean Journal of Ecology and Environment
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• v.51 no.2
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• pp.149-159
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• 2018

Twenty-nine wetlands (20 river type and 9 lake type wetlands) in Gyeongsangnam-do were investigated to understand the characteristics of fish assemblages by the wetland type and to suggest management strategies. As a result, $10.3{\pm}4.8$ species were collected from river type wetlands on average (${\pm}SD$) and $9.1{\pm}4.1$ species from lake type wetlands. Thus, there was no significant difference in the number of species between them (Mann-Whitney U test, P>0.05). However, the species that constitute the fish assemblage showed statistically significant differences between the two wetland types (PERMANOVA, Pseudo-F=2.9555, P=0.007). Furthermore, the species that contribute the most to each type of fish assemblage were Zacco koreanus (river type, 28.51%) and Lepomis macrochirus (lake type, 23.21%), respectively (SIMPER). The results of the NMDS analysis using the fish assemblage by place classified the species into three groups (river type, lake type, and others). The current wetland management is only focused on endangered species, but this study shows a difference in fish assemblage by wetland type. Therefore, a management system based information on endemic species, exotic species and major contribution species should be provided. Furthermore, the classification of some types of wetlands based on the present topography was found to be ambiguous, and wetland classification using living creatures can be used as a complementary method. This study has limitations because only two types of wetlands were analyzed. Therefore, a detailed management method that can represent every type of wetland should be prepared through the research of all types of wetlands in the future.

• Korean Journal of Environment and Ecology
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• v.21 no.3
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• pp.197-206
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• 2007

This study was conducted to survey the population of water birds wintering at the seven coastal wetlands of Jeollanam province including Suncheon Bay and Yeongsan Lake, from 2000 through 2003. The 90 species and 857,570 individuals in total were sighted at the seven survey sites. We classified the wintering water birds into seventeen groups of taxa based on the similar ecological attributes, among which, eight groups were found to inhabit the water surface or riparian areas. Classified groups that showed higher rate of using bay areas than that of lake areas were in the order of waders, gulls and swans. On the other hand, the groups that showed higher rate of using lake areas than that of using bay areas were revealed in the order of dabbling ducks, grebes and geese. In conclusion, there was a difference in the pattern between the two classified groups. As a result of the UPGMA cluster analysis using CCs ($S{\varnothing}rensen'a$ index of similarity and Ro (Horn's index of community overlap), the results showed that Suncheon Bay had the most unique species formation out of the seven areas. Bay and lake areas were different from each other in the formation of species and Individuals. As a result of combining the index rank according to the maximum aggregate count, the Suncheon Bay is ranked the highest in importance of the habitats for water birds, followed by the order of Boseong-Deukryang Bay, Gangjin Bay, Gocehongam Lake, Geumho Lake, Yeomam Lake, and Yeongsan Lake. Considered overall, the importance of the bay areas was relatively higher than that of reclaimed lake areas.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.427-432
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• 2016

The purpose of this study was to investigate drowning death patients on clinical care and prevention. Drowning accidents that occurred in the Republic of Korea were identified by using the Emergency Activity Daily Report Data from the National Emergency Management Agency (NEMA). The age of drowning accidents was 20-29 years (25.4%). Drowning cases for the months of August was 17.6%. The main circumstance involved in the drowning cases was swimming (45.0%). Half of swimming incidents related the drowning accidents of people attempting to save a life of a family member or friend from the water. The most common location was at a lake or reservoir (40.2%). Drowning is a main cause of accidents in the Republic of Korea. Preventive strategies that may be beneficial for persons contain life jackets or life rings supply, upgrading swimming ability, placing lifeguards based on public education activities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.887-894
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• 2016

In the underwater acoustic communication channels, a multipath reflection becomes the cause of obstacle. To solve this problem, a rake receiver has been required for which one could take the time diversity. However, there is a concern about using incorrect path to recover signals with a high weighting value as underwater acoustic communication channels have severe time-variant property. In order to prevent these problem, a rake receiver is proposed which is based on BER(bit error rate) train sequence duration. The performance is evaluated through lake trials; there are three methods that are a proposed rake receiver, a conventional rake receiver, and a non-rake receiver. As a result, the number of bit errors in the proposed rake receiver, that of bit errors in the conventional rake receiver, and that of bit errors in the non-rake receiver is 8, 45, and 72, respectively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.2
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• pp.87-91
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• 1997

Ecological stability of the Lake Shihwa, artificially made by the construction of the Shihwa Dike, was evaluated by the species composition and variation in biomass of zooplankton. Species composition and seasonal variation in biomass in the seaside stations were similar to those observed in nearby bays and coastal zone. However, those in the lake sites showed very different patterns. The brackish water copepod, Sinocaianus tenellus, held the first rank in every season (with more than 66% in spring, 98% in summer and fall, and 80% in winter). The species composition was very simple and the biomass (in terms of total individuals $m^{-3}$) varied markedly with season up to the order of $10^4$ magnitude. These results imply that the lake ecosystem made by the construction of Sihwa dike is in very unstable stage probably due to the input of industrial wastes as well as unpredictable variation in salt content caused by irregular control of the watergate of the dike and resultant irregular flow direction of the water through the gate.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.395-401
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• 2008

Genetic diversity and differentiation within or among nine populations of introduced fish, largemouth bass Micropterus salmoides were assessed by AFLP. The AFLP analysis using three primer combinations generated 299.2. AFLP bands and percentage of polymorphic bands were similar in those nine populations, ranging 14.1 to 21%. Heterozygosity and genetic diversity within or among populations were quite low for all of these populations with average values ranging from 0.054 to 0.067 and from 0.069 to 0.085, respectively. Analyses of pairwise distance and genetic similarity among nine populations of Micropterus salmoides also revealed the similar results with low genetic differentiation one another. Although pairwise Fst values were low, they were indicated a clear distinct genetic differentiation among the nine populations. These results indicate that very small population of the largemouth bass was first introduced to Paldang reservoir and they are widely spread at most of aquatic habitats in Korea.

• The Journal of the Acoustical Society of Korea
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• v.41 no.2
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• pp.218-226
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• 2022

The main characteristics of the underwater acoustic channel have varying multipath and fast fading. Especially, Frequency Shift Keying (FSK) signals with multiple frequency bands caused loss of information bits allocated on the specific frequencies due to selective fading phenomenon. Therefore, this paper proposes frequency gain control algorithm based on preamble error rates. The proposed algorithm estimates optimal gain value in the range of preamble error rate with less than 10 % for specific faded frequency. By employing turbo equalized FSK signals with rate of 1/3, the experiment was conducted on a lake in Munkyeong city with distance of 300 m to 500 m. The result confirms that packets are decoded successfully by applying proposed algorithm as increasing number of iterations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.400-403
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• 2009

본 연구에서는 평판 스페이스 프레임 구조물의 크기 및 형상최적화 기법을 개발하고자 한다. 이를 위해 평판 스페이스 프레임의 물량에 영향을 미치는 요소인 격자분할 수와 상 하부 평판사이의 높이를 주요 설계변수로 선정함으로써 부재크기 최적화뿐만 아니라 형상최적화 방안도 제시하였다. 또한 평판 스페이스 프레임의 절점 및 부재 자동생성방안이 고려되며 감도해석기법을 이용하여 개발된 최적화 프로그램을 예제모델에 적용하여 설계변수 변화에 따른 구조시스템의 최적의 대안을 강구하고자 한다.

• Journal of the Korean Geographical Society
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• v.35 no.2
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• pp.351-364
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• 2000

1980년 설치 이후 환경부는 환경정책과 환경관리에 대한 주요 업무 중의 하나로 자연환경의 보전에 주안점을 두고 있다. 또한 자연환경보전법에 의거하여 환경부는 자연환경상태에 대한 전국 단위의 자연환경조사를 실시하고 있다. 제1차 전국자연환경조사는 이미 1986-1990년에 실시하였고, 현재 교수 및 연구진의 참여 하에 제2차 전국자연환경조사(1997-2002)ff 실시하고 있다. 제2차 조사에서는 지형경관에 대한 조사가 포함되어 모든 종류의 지질 및 지형환경에 대한 조사가 이루어진다. 예를 들면 호수와 습지, 해안, 하천, 산지. 평야, 주빙하지형, 화산, 카르스트 및 구조지형 등이다. 조사지역은 육지 206개 소권역, 해안 145개 지점으로 나누고 6년에 걸쳐 매년 약 30개의 팀이 이 프로젝트에 참여하고 있다. 조사결과는 “지형경관도”로 편집, 인쇄될 예정이며 현존식생도, 동식물분포도와 함께 생태자연도로 작성될 예정이다. 제2차 조사에서 얻어진 방대한 양의 환경정보를 합리적이고 효율적으로 이용하기 위해서 환경부는 한경관리를 위한 이용과 응용에 환경정보시스템을 구축하고 있다.