• Title/Summary/Keyword: Out of distribution

Search Result 8,341, Processing Time 0.043 seconds

A Study on Wheel Load Distribution Factors of Skew Steel Box Girder Bridges (강상자형 사교의 윤하중분배계수)

  • Seo, Chang-Bum;Song, Jae-Ho;Kim, Il-Soo
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.13 no.4 s.56
    • /
    • pp.148-158
    • /
    • 2009
  • Firstly the problems of existing foreign code concerning wheel load distribution factor for skew box girder bridges have been examined, and the main parameters which have effects on wheel load distribution factors are evaluated in this study. Further finite element analyses on various skew steel box girder bridges are carried out. Based on the analysis results, formulas to determine wheel load distribution factors are proposed using multiple regression analysis. It is found when using the proposed formulas in this study weak points of existing specifications could be improved and also time spent at structural analysis should be saved a lot, so that the validity and practicality could be verified.

A Study on Eating-Out Style and Acceptance Intention of Artificial Seasoning: The Moderating Role of Consumers' Psychological Value

  • CHA, Seong-Soo;SEO, Bo-Kyung
    • The Journal of Asian Finance, Economics and Business
    • /
    • v.6 no.4
    • /
    • pp.171-177
    • /
    • 2019
  • This study aims to investigate the effect of eating-out types on the acceptance intention of artificial seasoning when consumers eat out at restaurants. Eating-out types considered to be typical when customers visit restaurants, such as the food-exploratory type, health-oriented type, and convenience-seeking type, were studied. Based on the research of previous studies, three eating-out types were selected for the study, which were "food-exploratory", "convenience-seeking", "health-oriented". This study was conducted by AMOS 22.0 with 300 questionnaires, and the Structural Equation Model (SEM) was used for examining the hypotheses as statistical method in this study. As a result, eating-out types such as "food-exploratory" and "convenience-seeking" were found to significantly affect the acceptance intention of artificial seasoning. However, consumers' acceptance intention of artificial seasoning differed depending on their consumption value. The path coefficients from food-exploratory type and health-oriented type to acceptance intention were more significant in the hedonic-oriented group than the utilitarian-oriented group. The results of this study suggest eating-out types relate to acceptance intention of artificial seasoning and provide meaningful implications for consumers' psychological consumption value when they consider artificial seasoning.

The Validation Study of Normality Distribution of Aquatic Toxicity Data for Statistical Analysis (수생태 독성자료의 정규성 분포 특성 확인을 통해 통계분석 시 분포 특성 적용에 대한 타당성 확인 연구)

  • OK, Seung-yeop;Moon, Hyo-Bang;Ra, Jin-Sung
    • Journal of Environmental Health Sciences
    • /
    • v.45 no.2
    • /
    • pp.192-202
    • /
    • 2019
  • Objectives: According to the central limit theorem, the samples in population might be considered to follow normal distribution if a large number of samples are available. Once we assume that toxicity dataset follow normal distribution, we can treat and process data statistically to calculate genus or species mean value with standard deviation. However, little is known and only limited studies are conducted to investigate whether toxicity dataset follows normal distribution or not. Therefore, the purpose of study is to evaluate the generally accepted normality hypothesis of aquatic toxicity dataset Methods: We selected the 8 chemicals, which consist of 4 organic and 4 inorganic chemical compounds considering data availability for the development of species sensitivity distribution. Toxicity data were collected at the US EPA ECOTOX Knowledgebase by simple search with target chemicals. Toxicity data were re-arranged to a proper format based on the endpoint and test duration, where we conducted normality test according to the Shapiro-Wilk test. Also we investigated the degree of normality by simple log transformation of toxicity data Results: Despite of the central limit theorem, only one large dataset (n>25) follow normal distribution out of 25 large dataset. By log transforming, more 7 large dataset show normality. As a result of normality test on small dataset (n<25), log transformation of toxicity value generally increases normality. Both organic and inorganic chemicals show normality growth for 26 species and 30 species, respectively. Those 56 species shows normality growth by log transformation in the taxonomic groups such as amphibian (1), crustacean (21), fish (22), insect (5), rotifer (2), and worm (5). In contrast, mollusca shows normality decrease at 1 species out of 23 that originally show normality. Conclusions: The normality of large toxicity dataset was not always satisfactory to the central limit theorem. Normality of those data could be improved through log transformation. Therefore, care should be taken when using toxicity data to induce, for example, mean value for risk assessment.

Density Distributions of Metallic Compounds in Particulate Matters (粒子狀 物質中 金屬成分의 密度分布)

  • 허문영;김형춘;손동헌
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.2 no.2
    • /
    • pp.9-18
    • /
    • 1986
  • For identification and apportionment of sources emitting particulate matters in environment, the multi-elemental characterization of size-density fractionated particulate matters was carried out. Eight types of samples were tested; soil, flyash released from burning of bunker-Coil, diesel oil, coal, and soft coal, urban road-way dust, urban dust fall, and airborne particulate matter. The fractions of particulate matters obtained by heavy liquid separation methos with a series of dichloromethane-bromoform were then analyzed using atomic absorption spectrophotometry for Ni, Cr, Cu, An, Fe, Al, and Mg. Each sample showed a different concentration profile as a function of density, and a number of useful conclusions concerning characterization of elemental distribution were obtained. From the density distributions of elements in soil, the maximum value was found for all elements in the density range of 2.2 $\sim 2.9g.cm^{-3}$, including the density of $SiO_2$. However, the distribution of metallic compounds with the density lower than $2.2g.cm^{-3}$ was prevalent in urban roadway dust, urban dust fall, and airborne particulate matter. And the density distribution curves of these urban dusts also have the higher distribution at the density of 2.2 - 2.9g.cm^{-3}$, including the density of wind-blown silica. This tendency generally was prevalent in the natural source elements, such as Al, Fe, Mn, and Mg. The maximum values were found in the density ranges of 1.3 $\sim 2.2g.cm^{-3}$ from the density distribution of elements in oil fired flyash. These distributions of anthropogenic source elements, such as Zn, Ni, Cu, and Cr were higher predominately than those of natural source elements. And the higher distribution was found in the density range of $2.2 \sim 2.9g.cm^{-3}$ from the density distribution of elements in coal and soft-coal fired flyash. These distributions showed similar patterns to soil. But anthropogenic source elements somewhat predominated at the density ranges of $1.3 \sim 2.2g.cm{-3} and 2.9g.cm^{-3}$ to soil. Therefore the higher distribution of anthropogenic source elements in the density ranges of $1.3 \sim 2.2g.cm^{-3} and 2.9g.cm^{-3}$ was considered as anthropogenic origin.

  • PDF

Characteristics of Distribution of Phytoplankton Communities in Three Estuarial Lakes of the Yeongsan River (영산강 하구역에 위치한 세 호수의 식물플랑크톤 군집 분포 특성)

  • Cho, Hyeon Jin;Na, Jeong Eun;Lee, Gun Ju;Lee, Hak Young
    • Korean Journal of Ecology and Environment
    • /
    • v.54 no.4
    • /
    • pp.291-302
    • /
    • 2021
  • The phytoplankton community in the estuarine system is affected by changes of physicochemical factors easily. The present study analyzed phytoplankton community distribution and similarity, in addition to exploring factors influencing variations in phytoplankton community structure in three lakes located in the Yeongsan River estuary from March 2014 to November 2017. We carried out non-multidimensional scaling (NMDS) and random forest analysis (RF) for comparing the pattern of phytoplankton distribution and the relationship between phytoplankton distribution and environmental variables. Similarity Percentage (SIMPER) and Analysis of Similarity (ANOSIM) were performed to figure out the similarity of phytoplankton community at each site of three lakes. From NMDS, Phytoplankton community distribution differed between Yeongsan and Gumho lakes, and the factors influencing the distribution of phytoplankton communities across the three lakes were water temperature, dissolved oxygen, total nitrogen (T-N), nitrate-N (NO3-N), and conductivity. NO3-N was a key factor influencing phytoplankton community structure in the three lakes based on RF. A total of 24 species were identified as indicator species in the three lakes studied, with the highest species numbers observed in Yeongsan Lake (13) and the lowest observed in Yeongam Lake (2). According to SIMPER and ANOSIM results, the phytoplankton community in Yeongsan and Yeongam lakes were similar, and they differed from those in Gumho Lake. In addition, the phytoplankton community structure varied across the study sites in the three lakes, indicating that water channels across the lakes a minor influence phytoplankton community distribution.

Bus-voltage Sag Suppressing and Fault Current Limiting Characteristics of the SFCL Due to its Application Location in a Power Distribution System

  • Kim, Jin-Seok;Lim, Sung-Hun;Kim, Jae-Chul
    • Journal of Electrical Engineering and Technology
    • /
    • v.8 no.6
    • /
    • pp.1305-1309
    • /
    • 2013
  • The application of the superconducting fault current limiter (SFCL) in a power distribution system is expected to contribute the voltage-sag suppression of the bus line as well as the fault-current reduction of the fault line. However, the application effects of the SFCL on the voltage sag of the bus line including the fault current are dependent on its application location in a power distribution system. In this paper, we investigated the fault current limiting and the voltage sag suppressing characteristics of the SFCL due to its application location such as the outgoing point of the feeder, the bus line, the neutral line and the 2nd side of the main transformer in a power distribution system, and analyzed the trace variations of the bus-voltage and fault-feeder current. The simulated power distribution system, which was composed of the universal power source, two transformers with the parallel connection and the impedance load banks connected with the 2nd side of the transformer through the power transmission lines, was constructed and the short-circuit tests for the constructed system were carried out. Through the analysis on the short-circuit tests for the simulated power distribution system with the SFCLs applied into its representative locations, the effects from the SFCL's application on the power distribution system were discussed from the viewpoints of both the suppression of the bus-voltage sag and the reduction of the fault current.

Live Load Distribution in Prestressed Concrete I-Girder Bridges (I형 프리스트레스트 콘크리트 거더교의 활하중 분배)

  • Kim, Kwang-Yang;Kang, Dae-Hui;Lee, Hwan-Woo
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2008.04a
    • /
    • pp.288-293
    • /
    • 2008
  • The standard prestressed concrete I-girder bridge (PSC I-girder bridge) is one of the most prevalent types for small and medium bridges in Korea. When determining the member forces in a section to assess the safety of girder in this type of bridge, the general practice is to use the simplified practical equations or the live load distribution factors proposed in design standards rather than the precise analysis through the finite element method or so. Meanwhile, the live load distribution factors currently used in Korean design practice are just a reflection of overseas research results or design standards without alterations. Therefore, it is necessary to develop an equation of the live load distribution factors fit for the design conditions of Korea, considering the standardized section of standard PSC I-girder bridges and the design strength of concrete. In this study, to develop an equation of the live load distribution factors, a parametric analysis and sensitivity analysis were carried out on the parameters such as width of bridge, span length, girder spacing, width of traffic lane, etc. Then, an equation of live load distribution factors was developed through the multiple linear regression analysis on the results of parametric analysis. When the actual practice engineers design a bridge with the equation of live load distribution factors developed here, they will determine the design of member forces ensuring the appropriate safety rate more easily. Moreover, in the preliminary design, this model is expected to save much time for the repetitive design to improve the structural efficiency of PSC I-girder bridges.

  • PDF

Distribution of Azotobacter in Rhizosphere and Sea (Rhizosphere와 해수에 있어서의 Azotobacter의 분포)

  • 홍순우;최영길
    • Korean Journal of Microbiology
    • /
    • v.12 no.1
    • /
    • pp.15-24
    • /
    • 1974
  • This experiment has been carried out with a view to elucidating the distribution of Azotobacter and their population size in rhizosphere and sea and designed ro compare the results with some environmental factors. Results of the experiment are summarized as follows: 1) It was observed that the population sizes of Azotobacter were decided upon the moisture content of soil and that the soil pH was one of the most impertant factors influencing the distribution of Azotobacter. 2)Population sizes of Azotobacter in rhizosphere were changed in accordance with the kinds of vegetation on soil: The rhizosphere where bamboo, corn, legume, and oak inhabit showed the largest population size of Azotobacter. On the other hand, rhizosphere of ginseng revealed no Azotobacter. However, the largest population of general fungi were measured at the rhizosphere. 3)Comparing the population sizes of general microbes in rhizosphere with those of non-rhizosphere, the population sizes of microbes in rhizosphere are larger than those of non-rhizosphere. 4)In coastal environments, population sizes of Azotobacter in surface water of sea are similar to those of the soil(mud) of tidal land. But the sizes are generally smaller than those of terrestrial soils.

  • PDF

Patterns of Vertical Distribution and Diel Vertical Migration of Zooplankton in the East Sea of Korea (Sea of Japan)

  • Park, Chul;Lee, Chang-Rae;Hong, Sung-Yun
    • Journal of the korean society of oceanography
    • /
    • v.32 no.1
    • /
    • pp.38-45
    • /
    • 1997
  • To find out the changes in vertical distribution patterns over the 24-h period, a key and the first step to tackle the problem of adaptive significance of diel vertical migration (DVM), vertically stratified time series samplings with multiple opening/closing plankton samplers were done in the East Sea of Korea (Sea of Japan). Sampling was done almost every 4 h for one day period following the same water parcel in Nov. 1995 and May 1996, respectively. Resultant patterns of vertical distribution showed that some species such as most abundant taxa Metridia pacifica and Scolecithyicella minor, both Copepoda, performed DVM even in the study area of strong thermal stratification. Their patterns of DVM such as distance scales and timing of movements were not the same each other, and they were separated from other taxa in the dendrogram obtained by the cluster analyses, Most minor taxa grouped in one, however, seemed not to do DVM in the study area of strong thermal stratification. They usually preferred the warmer surface layer where the foods were probably more abundant.

  • PDF

Cluster Analysis on the Distribution of Lichens in the Mt. Hanra (漢拏山 地依植物의 分布에 關한 集落分析)

  • Park Seung-Tai;Du-Mun Choe
    • The Korean Journal of Ecology
    • /
    • v.7 no.3
    • /
    • pp.119-131
    • /
    • 1983
  • The cluster analysis on the distribution of epiphytic lichens on the north, south, east and west slope of Mt. Hanra was carried out by three methods, sum of square algorithm (SSA), prinicipal component analysis (PCA) and multidimensional scaling method(MDS). Analysis of concentration (AOC) was used for the comparison between the lichen communities of north and south slope. The lichen species was identified 35 species by Hale and Culberson technique. The classification of sites by SSA method was divided into two areas in four slopes, and that of species by SSA, PCA and MDS methods was classified into three clusters in east slope, four clusters in south and west slope, and there clusters in north slope. The comparison between north and south slope of the distribution of lichens indicates that loight elevation of north slope (NH; 1600m~1900m) was similar to that of relative low elevation of south slope (SL; 1000m~1300m). The genus lichen, Anaptychia, Parmelia, Lobaria and peltigera was found as the dominant genus in both slopes.

  • PDF