• Title/Summary/Keyword: spatial variation

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A descriptive spatial analysis of bovine tuberculosis disease risk in 2015 in Gangwon-do, Republic of Korea

  • Kim, Eu-Tteum;Pak, Son-Il
    • Journal of Preventive Veterinary Medicine
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    • v.41 no.2
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    • pp.79-83
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    • 2017
  • In this study, we used a choropleth map to explore the spatial variation of the risk of cattle herds being bovine tuberculosis (BTB) positive in Gangwon-do in 2015. The map shows that the risk of being BTB-positive was lower in provinces located in the middle of Gangwon-do (Wonju, Youngwol, Peongchang, and Kangneung) than in other provinces. In addition, one province located in the north (Goseong) had a low risk of BTB. The estimate for the intercept of the spatial lag model was 0.66, and the spatial autocorrelation coefficient (lambda) was 0.20 (Table 1). The Moran's I was 0.33 with p-value of 0.02. In 2015, provinces located in the North West (Hwacheon) and East (Donghae) of Gangwon-do had a higher BTB risk. We identified some specific provinces at low BTB-positive risk, information that may prove useful for control of BTB in the study area.

Determination of the Coefficient of Variation of Shear Wave Velocity in Rock Filled Zone of CFRD (Concrete Faced Rock Filled Dam) for Reliability Based Analysis (신뢰성 기반 해석을 위한 국내 CFRD 사력존 재료의 전단파 속도 변동계수 결정)

  • Park, Hyung-Choon;Lim, Heui-Dae
    • Journal of the Korean Geotechnical Society
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    • v.33 no.4
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    • pp.17-24
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    • 2017
  • Shear wave velocity (or shear modulus) of rock filled zone of CFRD is very important factor in the evaluation of performance of CFRD under the load such as earthquake. A shear wave velocity profile can be determined by surface wave method but this profile has been uncertainty caused by spatial variation of material property in rock filled zone. This uncertainty in shear wave velocity profile could be evaluated by the reliability based analysis which uses a coefficient of variation of material property to consider uncertainty caused by spatial variation of material property. In this paper, the possible 600 shear wave velocity profiles in rock filled zone of CFRD were generated using the method based on harmonic wavelet transform and 8 shear wave velocity profiles by HWAW method in the field, and the coefficients of variation of shear wave velocity with depth were evaluated for the rock filled zone of CFRD in Korea.

Variation of Spatial Cognition According to Visual Perception and Psychological Responses for Lighting Environments in Rest Space (휴게실 공간의 조명환경에 대한 시각적 감지 및 심리적 반응에 따른 공간 인지도 변화)

  • Kim, Jae-Sang;Lee, Ji-Hyun;Kim, Soo-Young
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.5
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    • pp.443-453
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    • 2012
  • This study examines visual perception and spatial satisfaction according to lighting conditions. Field measurements and surveys were performed in three rest space of university buildings where various lighting conditions were employed. Results indicate that overall impression of space improved when low color temperature, such as 3,000 K governed overall lighting environment and accent lighting was used for wall surfaces. Lighting conditions that kept uniform illuminance levels using area light sources containing fluorescent lamps with 6,500 K failed to keep favorable spatial satisfaction for space. High color temperature was not recommended for lighting in rest space. Asymmetrical illuminance levels formed by low color temperature such as 3000 K is recommended to keep positive mood and improve spatial satisfaction in rest space. Overall impression of the space was influenced by visual comfort, color temperature, spatial satisfaction and brightness. Spatial satisfaction for space was effectively impacted by psychological comfort, color temperature and overall impression for lighting conditions. Psychological comfort in space was influenced by color temperature, spatial satisfaction and visual annoyance from reflected light.

Development of the Test Tool of Astronomical Spatial Concept Level (천문학적 공간개념 수준에 관한 검사도구 개발)

  • Seo, Chang-Hyeon;Lee, Hang-Ro;Kim, Hee-Soo
    • Journal of the Korean earth science society
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    • v.24 no.6
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    • pp.508-523
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    • 2003
  • This study has developed the test tool to measure the level of spatial concept in the astronomy education for high school students. The items of the test tool are composed of basic elements (spatial position, spatial reasoning, spatial variation) forming spatial concepts in the astronomy. The test tool was applied to the 274 high school students. As a result of item analysis, the test tool showed that the content validity was 98%, the reliability (KR 20) was 0.84, the measure the level of astronomical spatial concept for the high school students.

Geo-statistical Analysis of Growth Variability in Rice Paddy Field (벼 재배 포장 생육변이의 공간통계학적 해석)

  • 이충근;성제훈;정인규;김상철;박우풍;이용범;박원규
    • Journal of Biosystems Engineering
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    • v.29 no.2
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    • pp.109-120
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    • 2004
  • To obtain basic information for precision agriculture, spatial variability of rice growth condition was evaluated in 100m ${\times}$100m paddy field. The rice growth condition of four hundred locations in the field were investigated to analyze the spatial variability of their properties ; SPAD, plant length and tiller number. Geostatistical analysis was carried out to examine within-field spatial variability using semivariograms and kriged maps as well as descriptive statistics. Descriptive statistics showed that the coefficient of variation for SPAD, plant length, and tiller number exceeded 5.70 %, suggesting a relatively high variability. Geostatistical analysis indicated a high spatial dependence for all the properties except for the second tiller number. The range of spatial dependence was about 20 m for SPAD, plant length, and tiller number. Based on the results of spatial dependence, kriged maps were prepared for the properties to analyse their spatial distribution in the field. The results reflected the history of field management. In conclusion, the need for site-specific field management and possibility of precision agriculture were demonstrated even in an almost flat paddy field.

The Land Surface Temperature Analysis of Seoul city using Satellite Image (위성영상을 통한 서울시 지표온도 분석)

  • Jeong, Jong-Chul
    • Journal of Environmental Impact Assessment
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    • v.22 no.1
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    • pp.19-26
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    • 2013
  • The propose of this study is to analyze the optimum spatial resolution of the urban spatial thermal environment structure and to evaluate of the possibility detection using aerial photographs and thermal satellite images. The proper techniques of the optimum spatial resolution for the urban spatial thermal environment structure were analyzed. Thermal infrared satellite image of Seoul city were used for the change rate of surface temperature variation and suggested to the spatial extent and effects of urban surface characteristics and spatial data was interpreted as regions. To extract the surface temperature, Landsat thermal infrared satellite image compared with an automatic weather station data and in the field of the measured temperature and surface temperature by thermal environment affects, the spatial domain has been verified. The surface temperature of the satellite images to extract after adjusting surface temperature isotherms were constructed. The changes in surface temperature from 2008 to 2012 the average surface temperature observation images of changing areas were divided into space. The results of this study are as follows: Through analysis of satellite imagery, Seoul city surface temperature change due to extraction comfort indices were classified into four grades. The comfort index indicative of the temperature of Gangnam-gu, $23.7{\sim}27.2(^{\circ}C)$ range and Songpagu, a $22.7{\sim}30.6(^{\circ}C)$ respectively, the surface temperature of Yeouido $25.8{\sim}32.6(^{\circ}C)$ were in the range.

Design Method Development of Smart TMD for Retractable-Roof Spatial Structure (개폐식 대공간 구조물을 위한 스마트 TMD 설계기법 개발)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.17 no.3
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    • pp.107-115
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    • 2017
  • In this paper, a structural design method of a smart tuned mass damper (TMD) for a retractable-roof spatial structure under earthquake excitation was proposed. For this purpose, a retractable-roof spatial structure was simplified to a single degree of freedom (SDOF) model. Dynamic characteristics of a retractable-roof spatial structure is changed based on opened or closed roof condition. This condition was considered in the numerical simulation. A magnetorheological (MR) damper was used to compose a smart TMD and a displacement based ground-hook control algorithm was used to control the smart TMD. The control effectiveness of a smart TMD under harmonic and earthquake excitation were evaluated in comparison with a conventional passive TMD. The vibration control robustness of a smart TMD and a passive TMD were compared along with the variation of natural period of a simplified structure. Dynamic responses of a smart TMD and passive TMD under resonant harmonic excitation and earthquake load were compared by varying mass ratio of TMD to total mass of the simplified structure. The design procedure proposed in this study is expected to be used for preliminary design of a smart TMD for a retractable-roof spatial structure.

A Study on the Transition of Spatial Structure in Libraries with Special Reference to Rhizome and Hypertext (리좀과 하이퍼텍스트 관점에서 본 도서관 공간구조의 이해)

  • Choi, Yoon-Kyung;Kim, Min-Jung
    • Korean Institute of Interior Design Journal
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    • v.15 no.6 s.59
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    • pp.111-119
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    • 2006
  • The spatial property of contemporary library is now rapidly changing through the spatial expansion of knowledge and information, the reduction of information storing facility, the variation of approaching methods by digital shift and the transition of social recognition as a cultural facility. Also the spatial characteristics with referring characters have developed such as, decentralization, de-construction, de-boundary, individual space, erasing of boundary, flow of space which extends infinitely. The main process of library origination, the systematic classification, and the storage system concluding with the demand and value of the information by changing social demands and the role of the widest ranged facility. And 5 themes, such as, hierarchy, center, storage, boundary, and symbol, as a changed spatial concept and analyzed in the case of library plans and libraries which are actually built. The significant purpose of this research is to propose that rhizomatous intellectuality and hypertext could be a theoretical background of the contemporary architecture and could be a viewpoint of the transition of spatial structure in libraries. A future library should have spatial property embracing various social changes and needs and for this respect, it is necessary to approach and analyze through the architectural explication from diverging points of view.

On the Variations of Spatial Correlation Structure of Rainfall (강우공간상관구조의 변동 특성)

  • Kim, Kyoung-Jun;Yoo, Chul-Sang
    • Journal of Korea Water Resources Association
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    • v.40 no.12
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    • pp.943-956
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    • 2007
  • Among various statistics, the spatial correlation function, that is "correlogram", is frequently used to evaluate or design the rain gauge network and to model the rainfall field. The spatial correlation structure of rainfall has the significant variation due to many factors. Thus, the variation of spatial correlation structure of rainfall causes serious problems when deciding the spatial correlation function of rainfall within the basin. In this study, the spatial rainfall structure was modeled using bivariate mixed distributions to derive monthly spatial correlograms, based on Gaussian and lognormal distributions. This study derived the correlograms using hourly data of 28 rain gauge stations in the Keum river basin. From the results, we concluded as following; (1) Among three cases (Case A, Case B, Case C) considered, the Case A(+,+) seems to be the most relevant as it is not distorted much by zero measurements. (2) The spatial correlograms based on the lognormal distribution, which is theoretically as well as practically adequate, is better than that based on the Gaussian distribution. (3) The spatial correlation in July exponentially decrease more obviously than those in other months. (4) The spatial correlograms should be derived considering the temporal resolution(hourly, daily, etc) of interest.

Motion Error Analysis of an Porous Air Bearing Table (다공질 공기베어링 테이블의 운동오차 해석)

  • Park, Cheon-Hong;Lee, Hu-Sang
    • 연구논문집
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    • s.34
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    • pp.101-112
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    • 2004
  • In order to analyze the motion errors of the aerostatic stage, it is necessary to consider the influence of the moment variation occurredinside the pads. In this paper, a motion error anaysis method utilizing the transfer functions on the reaction force and moment is proposed, and general characteristics of the transfer functions are discussed. Calculated motion errors by the proposed method show good agreement with the ones calculated by Multi Pad Method, which is considered the entire table as an analysis object. Also, by the introduction of the transfer function of motion errors, which represent the relationship between the spatial frequency components of the rail form error and motion errors, motional characteristics of the porous aerostatic stage can be generalized. In detail, the influence of the spatial frequencies is analyzed quantatively, and the patterns of the insensitive frequencies which almost do not affect the linear motion error or angular motion error according to the rail length ratio and the number of the pad are verified. The relationship between the moment variation occurred inside the pads and the motion errors is also verified together.

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