• Title/Summary/Keyword: principal component analysis

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Temporal variation of wintering bird population and environmental factors in Donglim reservoir (동림저수지에서 월동조류 개체군의 시계열적 변화와 환경 요인)

  • Park, Jongchul;Kim, Woo-Yuel
    • Journal of Wetlands Research
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    • v.19 no.2
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    • pp.223-229
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    • 2017
  • This study analyzed the relationship between environmental factors and the temporal changes of the bird populations during the every January from 1999 to 2016 (18 years) in Donglim reservoir. 'Winter Waterbird Census of Korea' data by National Institute of Biological Resources were used for the bird population data, and principal component analysis and cluster analysis were used to analyze the changes of annual population. The average temperature of January and the average storage rate of the reservoir were used as environmental factors. According to the results of the study, the population changes in the study area can be explained by the increase and decrease of two water bird groups and a mountain bird group. The average temperature of the years when the population of water bird groups increased was more than $1.4^{\circ}C$ in comparison with the year when mountain birds increased. On the other hand, the influence of the water content was not clear. The visiting of Baikal Teal affected by temperature was a factor affecting the other group of water bird and a mountain bird group. The results of this study suggest that the temperature change affects the global spatial distribution of birds and the migration of large population species such as Baikal Teal affects species composition and populations of birds at local scale. Therefore, understanding of environmental changes at large scale and spatial distribution of species and flock contributes to understand the temporal variation of the bird population at regional or local scales.

The Analysis of Awareness on Transportation Demand Management Policy and A Study on Mobility Management (교통수요관리정책에 대한 의식분석과 교통행동관리(Mobility Management)에 관한 연구)

  • HA, Jongju;JUNG, Hun Young
    • Journal of Korean Society of Transportation
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    • v.35 no.1
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    • pp.50-62
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    • 2017
  • As the use of private cars increases along with the technological advancement in the automobile industries and their capabilities to supply, a wide range of issues are followed including the increase in traffic congestion costs, pavement damages and more. In spite of consistent effort to resolve such urban traffic problems, the modal share rate of private cars continuously increases, thus it is becoming more important to explore the ways to enable drivers to take reasonable measures, in self-motivated manner, by taking part of the transportation demand management policy rather than to rely on the strict enforcement of control policy. Considering that the urban transportation infrastructures are in much better shape than before, it is necessary to implement Mobility Management (MM) that induces reasonable usage of private cars by promoting the change in one's consciousness and behavior through communication. Hence, the research studies the factors that influence the mobility through the survey targeting the citizens of Busan on their awareness on the former transportation demand management policy, to explore the ways to motivate the citizens' involvement in reducing the use of private cars as a measure of Mobility Management.

Estimation of Measurement Uncertainty for the HPLC Analysis of Deoxynivalenol in Wheat (밀에서 HPLC에 의한 데옥시니발레놀 분석의 측정불확도 산정)

  • Ok, Hyun-Ee;Chang, Hyun-Joo;Ahn, Jang-Hyuk;Cho, Jae-Young;Chun, Hyang-Sook
    • Korean Journal of Food Science and Technology
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    • v.41 no.3
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    • pp.258-264
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    • 2009
  • The principal objective of this study was to estimate the measurement uncertainty associated with determination of deoxynivalenol (DON), a mycotoxin generated by Fusarium strain, in food. In service of this goal, wheat as a food matrix was analyzed via high performance liquid chromatography-ultraviolet (HPLC-UV) detection using an immunoaffinity column for clean-up. The uncertainty sources in the measurement process were identified by sample weight, final volume, and sample concentration in extraction volume with components including standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. The expanded uncertainty for DON at a concentration of 300 ${\mu}g/kg$ was estimated as 71.62 ${\mu}g/kg$ using a coverage factor of two, which provides a confidence level of approximately 95%. The most influential component in the uncertainty sources was the recovery of the wheat matrix, followed by the calibration curve. These results indicate that all efforts may be directed toward reducing the uncertainties of the recovery of the wheat matrix and the calibration curve to obtain a reliable HPLC-UV method for DON analysis in wheat.

Comparison of the Floodplain Vegetation Structure According to Existence of Lateral Connectivity in Streams (하천의 횡적 연결성 유무에 따른 홍수터 식생 구조의 비교)

  • Chu, Yunsoo;Jin, Seung-Nam;Cho, Hyunsuk;Cho, Kang-Hyun
    • Journal of Wetlands Research
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    • v.19 no.3
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    • pp.327-334
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    • 2017
  • The flood pulse in streams enhances the biodiversity and ecosystem services of the channel-floodplain ecosystems by exchanging water, nutrients, sediments and organisms. However, the lateral connectivity in most streams of Korea has been disrupted by the levee constructions for the purpose of flood control and land use of floodplains. To compare the characteristics of floodplain vegetation according to existence of lateral connectivity in streams, we investigated the geomorphological and soil environmental factors and structures and distribution of vegetation in the floodplains connected and isolated by levee to the channel in Cheongmi Stream, Seom River, Hwangguji Stream, Mangyeong River, Gomakwon Stream, and Boseong River, Korea. In comparison of soil environments, moisture and clay contents were higher in the isolated floodplain than in the connected floodplain. According to the result of principal component analysis (PCA) using environmental data, the environments of the connected floodplain and the isolated floodplain were separated by soil moisture contents, soil texture and distribution altitude of the vegetation. The results of detrended correspondence analysis (DCA) using vegetation data showed that the isolated floodplain was dominated by the hydropythic communities of diverse life form and that the connected floodplain was dominated by the hygrophytic communities that endure disturbance. In conclusion, it is thought that the vegetation of the floodplain changed to the lentic wetland vegetation dominated by diverse hydrophytes as the floodplain was isolated from the channel by artificial levees.

Fish Community Structure of the Former Channel Isolated by Channelization in the Mangyeong River, Korea: Implications for Connectivity Restoration (만경강에서 하천정비에 의하여 격리된 구하도의 어류 군집 구조: 연결성 복원을 위한 제안)

  • Kim, Seog Hyun;Cheon, Hyoung Tae;Cho, Kang-Hyun
    • 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.

Shape Deformation Monitoring for VLBI Antenna Using Close-Range Photogrammetry and Total Least Squares (근접사진측량과 Total Least Squares를 활용한 VLBI 안테나 형상 변형 모니터링 방안 연구)

  • Kim, Hyuk Gil;Yun, Hong Sik
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.1
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    • pp.99-107
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    • 2016
  • In order to maintain the precise positioning accuracy of the VLBI system, the shape deformation found in antenna structure should be monitored. In fact, reduced the antenna gaining of an electromagnetic wave reception from the Quasar has been particularly expected due to the shape deformation of main reflector in VLBI antenna. Therefore, the importance of shape deformation monitoring for the main reflector has been significantly increased. The main reflector has come out as the high potential for deformation in the VLBI structure. The fact has led us to investigate the monitoring system for the main reflector based on the efficient algorithm in accordance with the close-range photogrammetry, which of expecting to be utilized as the continuous and automated monitoring system for the structure deformation in the near future. Ten fitting lines were estimated with the TLS for feature points of distributed in all directions from the main reflector. The resultant intersection point of estimated fitting lines was calculated by using the nearest point calculation algorithm, based on those non-intersection lines. Following to the intuitive basis for the time series analysis, the results was able to provide the calculation of numerical variation in the intersection point, which is represented in 3-axis,; that we are expecting to open the way for predicting a deformation rate as well as deformation direction

Effects of High Hydrostatic Pressure and pH on the Reduction of Garlic Off-flavor (초고압처리 시간과 pH 변화에 의한 마늘의 이취성분 저감화)

  • Lim, Chae-Lan;Hong, Eun-Jeung;Noh, Bong-Soo;Choi, Won-Seok
    • Korean Journal of Food Science and Technology
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    • v.42 no.5
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    • pp.533-540
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    • 2010
  • Effects of pH (1.8-10.2) and time (56 sec-15 min 4 sec) at high hydrostatic pressure (500 MPa) on the reduction of volatile compounds in garlic were studied. Volatile components of garlic were obtained from the headspace, analyzed, and identified by gas chromatography (GC)-mass spectrometry and an electronic nose. Nineteen sulfur compounds were identified as major compounds in garlic, and furan, aldehydes, alcohols, and ketones were also detected. Off-flavor compounds were more effectively reduced under strong acidic conditions. As the residence time at 500 MPa increased from 56 sec to 15 min 4 sec, the total amount of volatile compounds decreased significantly. The total amount of sulfur compounds decreased about 70% compared to those of raw garlic when the garlic was soaked in buffer (pH 6.0) and treated at 500 MPa for 15 min 4 sec. A principal component analysis showed that the off-flavors of garlic were reduced by the operating time of high hydrostatic pressure as well as pH treatment. The correlation coefficient of the results between GC and the electronic nose analysis was 0.9620. Therefore, pH and high hydrostatic pressure treatment could be used as an efficient method for reducing of garlic off-flavor.

Sensory characteristics of commercial rice cookies and snacks in market (시판 쌀과자의 관능적 품질 특성)

  • Rhee, Sook-Jong;Lee, Jang-Eun;Kim, Mi-Ryung
    • Food Science and Preservation
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    • v.20 no.3
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    • pp.348-355
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    • 2013
  • This study was conducted to analyze the sensory profiles of commercial rice cookies and snacks in the market and to provide fundamental data on the development of rice cookies and snacks. The sensory characteristics of 10 kinds of Korean commercial rice cookies and snacks were evaluated using a sensory test and were analyzed via quantitative description analysis (QDA) and principal component analysis (PCA), depending on their rice contents and processing methods. The rice cookies and snacks with less than 30% rice contents and that were fried were preferred, and their grainy attribute was related to the preference for them. Then 27 kinds of commercial rice cookies and snacks from three countries, Japan, the U.S.A. and China, were also evaluated and compared with those from Korea. While the Korean commercial rice cookies and snacks were sweet, grainy and crispy, those of Japan were not sweet and instead, were salty and crispy.

Distribution Characteristics of Weeds and Vegetation Types in Cnidium officinale Field (천궁밭 발생잡초 및 군락특성)

  • Kim, Duk-Hwan;Park, Jae-Man;Kang, Sang-Mo;Lee, Seok-Min;Seo, Chang-Woo;Lee, In-Yong;Lee, In-jung
    • Weed & Turfgrass Science
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    • v.4 no.4
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    • pp.279-287
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    • 2015
  • The present research was carried out in order to investigate the occurrence of problematic weed species in Cnidium officinale Makino. Field in South Korea. Total 53 sites of the 3 different regions in S. Korea were investigated from May to October, 2014. In Cnidium officinale fields, the identified weeds were distributed in 35 families and 99 species. Total 5 communities that consist of Commelina communis, Eleocharis kuroguwai, Persicaria vulgaris, Chenopodium album-Acalypha australis, and Galinsoga ciliata dominated the appearance. The weeds occurred in Cnidium officinale fields were divided into three groups in principal component plot analysis (PCA). It was observed that in control weeds plots; 20 plants of Cnidium officinale fresh weight is 739.9 g while the uncontrolled plots have no Cnidium officinale plants. The current investigation could be useful for estimation of future weeds occurrence, weed flora dynamics and establishment of weed control methods in Cnidium officinale fields in Korea.

A Study on Pollution Levels and Source of Polychlorinated Biphenyl (PCB) in the Ambient Air of Korea and Japan (한국과 일본의 환경대기 중 폴리염화비페닐(PCB)의 농도수준 및 발생원 해석에 관한 연구)

  • Kim, Kyoung-Soo;Song, Byung-Joo;Kim, Jong-Guk;Kim, Kyeo-Keun
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.2
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    • pp.170-176
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    • 2005
  • This study was conducted to investigate the level of PCBs and distribution of PCB congeners in the ambient air of Korea and Japan. The source of PCBs were also studied by a statistical method. The TEQ concentration of PCB in the ambient air of Korea and Japan were between 0.003 and $1.01\;pgTEQ/m^3$(mean value : $0.22\;pgTEQ/m^3$) and between 0.002 and $0.014\;pgTEQ/m^3$ (mean value: $0.007\;pgTEQ/m^3$), respectively. The ambient air of industrial area of Korea showed a fluctuation in PCB concentration than other sampling area. The isomer distribution patterns in the ambient air was more or less similar in all sampling places. In addition, highly chlorinated homologues ($7{\sim}10CB$) were detected in the only Korea industrial area. This observation suggests that there is a possibility of specific source of PCBs in the industrial area. The source identification of PCB in ambient air was performed using multivariate statistical analysis(principal component analysis). As a result, it is estimated that the Korean ambient air was more influenced by combustion process than the ambient air of Japan and also the effect of PCB commercial products was relatively a small.