• Proceedings of the Korean Society of Computer Information Conference
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• 2009.01a
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• pp.65-68
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• 2009

제품 개발에 있어서 사용자작업분석은 기본적인 과정이다. 이러한 과정이 전문가 분석의 의해 기능적인 관점에서 분석함으로서 신제품이나 새로운 요구가 추가로 필요한 제품 개발에 있어서 사용자 테스크를 이해하는데 객관적으로 사용자의 요구를 반영하기에는 어려운 점이 있다. 이러한 문제점을 고려하여 디지털 TV에서 예상되는 사용자 테스크를 수집하여 메뉴설계 및 정보구조를 이해하기위한 객관적인 자료를 얻기 위해 수집데이터를 척도화하고 통계적 군집분석을 이용하여 테스크를 분류하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.52-54
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• 2006

특정한 기능을 하는 DNA 조각은 특정한 염기 서열들을 가진다. 이를 이용하여 특정 조각의 DNA 서열을 위치 점수 행렬을 이용하여 표현할 수 있다. 하지만 찾고자 하는 DNA 부분들이 완전히 밝혀진 것이 아닐 수 있다. 따라서 현재 밝혀진 정보만을 이용하여 위치 점수 행렬을 만들 경우, 실제 서얼 패턴이 아닌 편중된 정보가 얻어질 수 있다. 따라서 본 논문에서는 위치 점수 행렬의 혼합 모델을 이용하여, 각각의 특정 군집들을 대표할 수 있는 행렬들을 구분하여 구성하였다. 본 논문에서는 약 22개의 염기로 구성된 microRNA 서열 중, 초반부의 8개의 염기 서열정보를 이용하여, 이들 위치의 서열상의 특성을 확인해 보고자 하였다. miRNA 서열을 대표하기 위한 위치 점수 행렬들은 구분하여 만들고, EM 알고리즘을 이용하여 학습한다. 학습 결과 얻어진 혼합 모델과 은닉 변수를 통해 microRNA들을 군집화하고, 각각의 군집에 속한 microRNA 서열의 특성을 확인한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.84-86
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• 2020

드론을 활용한 산업이 많은 관심을 받고 있다. 군집비행 연구는 산업 분야, 군사 분야에서 주요작업 성공확률을 높일 수 있다. 본 논문에서는 전파 음영지역에서의 드론의 군집비행 제어를 위해 얼굴인식을 바탕으로 위치제어를 수행한다. 이러한 기능의 구현을 통해 드론의 효과적인 군집비행이 가능할 것이며 정밀한 제어가 요구되는 분야에서 이용 가능할 것으로 기대된다. 향후 추가적인 제어방식으로 개선할 것이다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.32-38
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• 2018

Studies on classification of national roads have been continued, but there is little research on the classification of urban arterial roads. Due to the increase of traffic volume, urban arterial roads do not perform well as main roads. In this paper, the function of urban arterial road was established by using cluster analysis using traffic characteristics. Traffic characteristics such as traffic volume, weekend coefficient and speed coefficient were used to establish the functions of 55 main arterial roads in Seoul. The results of this paper are compared with those of the method using AADT. The method using AADT classifies the characteristics according to the traffic volume of the whole lane. In this paper, however, the results are derived using the traffic volume per lane reflecting the actual traffic volume. In addition, the functional classification of the arterial roads in Seoul was compared with the results of this paper to verify that the traffic characteristics were reflected. As a result, the method presented in this paper is more effective in showing traffic characteristics than the current highway functional classification method, and the functional classification system will be helpful for road extension and planning design.

• Fire Science and Engineering
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• v.25 no.1
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• pp.72-77
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• 2011

The effort of transferring some parts of urban functions to the underground space is growing trend among modem cities because of the limit of horizontal land use, the rise of land value, the diversification of human desire, etc. Thus, the basement of building and the subway station have deepened. It calls our attention to safety about evacuation from the underground space to the ground. Until now, the study about crowding walk in stairs has been progressed, focusing on the crowding walk that is going down the stairs, and there is no study about crowding walk that is going up the stairs. This study measured walking pace by crowd density that is going up the stairs in the subway station stairs making one-way movement of crowd. The actual survey showed that the mathematical relation 'V=0.638-0.0949p' determines going up walking velocity at a gradient of $23^{\circ}$, and the mathematical relation will be 'V=0.597-0.1067p' at a gradient of $30^{\circ}$, when it is converted, based on the average walking velocity of crowd by the slope of the stairs which is recommended by Architectural Institute of Japan.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.161-169
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• 2007

Global climate changes including elevated $CO_2$, drought, and global warming may influence greenhouse gas emissions in wetlands. A variety of microbial communities including denitrifiers and methanogens play a key role in determining such processes. In this paper we summarize current knowledge on the effects of climate changes on $CO_2,\;CH_4$, and $N_2O$ production and microbial communities mediating those processes in wetlands. Elevated atmospheric $CO_2$ and warming generally increase gas emissions, but effects of droughts differ with gas type and drying level. The responses of microbial community to climate changes in terms of composition, diversity and abundance are still in question due to lack of studies in wetlands. Based on the present review, it is suggested that future studies on microbial processes should consider microbial community and relationships between microbial function and structure with diverse environmental factors including climate changes. Such knowledge would be crucial to better understand and predict accurately any shifts in ecological functions of wetlands.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.4
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• pp.215-222
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• 1998

The objective of this study was to investigate the effects of physico-chemical environmental factors on the changes of bacterial population from two sites used for drinking water and eight sites polluted with various pollutant in Seoul city. In all the stations except for two sites used for drinking water, the concentrations of nitrate- nitrogen and ammonia were in excess of the criteria of groundwater quality by the result of analysis of 40 variations including physicochemical environmental factors, heavy metals, and bacterial populations. The numbers of total bacteria, heterotrophic bacteria and functional groups of bacteria were ranged from 5.1 to 41.4${\times}$10$\^$5/cells/ml and from 0.01 to 29.6${\times}$10$^4$cfu/ml, respectively. The activities of extracellular enzymes showed the ranges of 0.005∼11.3${\mu}$M/l/hr and its order to lipase, phophatase, ${\beta}$-glucosidase, cellulase, chitinase, amylase. The results of correspondence and multidimensional scaling analysis between bacterial populations and its physico-chemical environmental factors were explained the effects of physico-chemical environmental factors according to site characters and separated four group, which is accord with potential pollutants at wells.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.305-319
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• 2022

The community temperature index (CTI) reflects the temperature and environmental preferences of the community. We investigated the distribution patterns of major aquatic insect assemblages (Ephemeroptera, Plecoptera, and Trichoptera; EPT) based on CTI in streams of South Korea. We selected unpolluted 151 study sites at upper streams(less than 3^rd) with less than 1.5 mg L^-1 of biochemical oxygen demand. Study sites were clustered into six groups based on the similarities of their EPT composition. All three orders showed a continuous decrease in the number of species as CTI increased, especially in Plecoptera. In addition, the functional feeding groups were also significantly changed according the CTI changes. Temperature tolerance range of each group's indicator species varied according to the CTI of the group. Finally, changes of CTI reflected differences of EPT assemblages according to the differences of environmental condition including temperature. Therefore, CTI can be applied to the evaluation and preservation of stream ecosystems and prediction of community changes due to climate change.

• Ecology and Resilient Infrastructure
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• v.2 no.1
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• pp.22-32
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• 2015

This study investigated the difference in fish community structures in a main channel and an isolated former channel, considering the environmental factors in the Mangyeong River, Korea. Principal component analysis (PCA) with environmental factors showed that former channels were composed of a fine substrate covered by in-stream vegetation, whereas the main channel was covered by a wide range of substrates with a higher dissolved oxygen and conductivity. The result of the hierarchical cluster analysis with species abundance delineated to the four main groups; three abandoned channel groups and one main channel group. Non-metric multidimensional scaling (NMDS) showed that fish community structures of each study site differed from environmental factors: former channel fish communities were positively related to in-stream vegetation cover, whereas main channel fish communities were positively associated with dissolved oxygen and conductivity. The results indicated that channelization, where there was a separation between the former channel and the main channel, had detrimental effects on fish community structures of both the main channel and the abandoned channel in the Mangyeong River. In conclusion, this study suggested that the connectivity between the main channel and abandoned channel were required to enhance both habitat structural diversity and species diversity of the Mangyeong River.

• Ecology and Resilient Infrastructure
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• v.4 no.1
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• pp.34-43
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• 2017

The Naeseong Stream as a tributary of Nakdong River has conserved the unique structure and function of a typical sand-bed stream ecosystem. However, it is expected to change the stream bed environments and then the fish fauna in the downstream of the dam after the operation of the Yeongju Dam from 2016. We collected fishes and investigated their habitat environments from 2014 to 2016 in the downstream of the Yeongju Dam under construction in order to monitor changes in habitat environment, fauna and community structure of fishes in the Naeseong Stream. The size of the bed materials increased immediately downstream of the Yeongju Dam under construction. Before the operation of the Yeongju Dam, Zacco platypus was dominated and Opsarichthys uncirostris amurensis, Coreoleuciscus splendidus, Hemibarbus longirostris and Pseudogobio esocinus were sub-dominated according to the different sampling sites. Hemibarbus labeo, H. longirostris, Pseudogobio esocinus, Gobiobotia nakdongensis, Cobitis hankugensis and Leiocassis ussuriensis were found as a psammophilous fish specific to sand stream in the Naeseong Stream. At the downstream of the dam, the fish community was classified into a group of gravel-bed fishes such as Microphysogobio yaluensis, Coreoleuciscus splendidus and Coreoperca herzi and a group of sand-bed fishes such as Hemibarbus labeo, Cobitis hankugensis and Gobiobotia nakdongensis. These fish communities gradually tended to change from sand-bed fish community to gravel-bed fish community during the construction of the Yeongju Dam. Therefore, it is necessary to collect the baseline data for the stream ecosystem conservation in the sandy stream by continuously monitoring changes in the environment and fish in the downstream of the Youngju Dam.