• Title/Summary/Keyword: Density index

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Selection of Spatial Regression Model Using Point Pattern Analysis

  • Shin, Hyun Su;Lee, Sang-Kyeong;Lee, Byoungkil
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.3
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    • pp.225-231
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    • 2014
  • When a spatial regression model that uses kernel density values as a dependent variable is applied to retail business data, a unique model cannot be selected because kernel density values change following kernel bandwidths. To overcome this problem, this paper suggests how to use the point pattern analysis, especially the L-index to select a unique spatial regression model. In this study, kernel density values of retail business are computed by the bandwidth, the distance of the maximum L-index and used as the dependent variable of spatial regression model. To test this procedure, we apply it to meeting room business data in Seoul, Korea. As a result, a spatial error model (SEM) is selected between two popular spatial regression models, a spatial lag model and a spatial error model. Also, a unique SEM based on the real distribution of retail business is selected. We confirm that there is a trade-off between the goodness of fit of the SEM and the real distribution of meeting room business over the bandwidth of maximum L-index.

An Experimental Study of Radiographic Density of Alveolar Bone and Cortical Thickness of Mandible by Osteoporosis (골다공증에 따른 치조골 방사선사진농도와 하악하연두께의 변화에 대한 연구)

  • Lee Byeong-Do
    • Imaging Science in Dentistry
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    • v.30 no.4
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    • pp.235-242
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    • 2000
  • Purpose: To evaluate the effect of the systemic osteoporosis on radiographic density of alveolar bone and cortical thickness of mandible. Materials and Methods: The bone mineral density values of lumbar and femur were measured by dual-energy X-ray absorptiometry and T scores of lumbar, femur were obtained respectively. Radiographic densities of alveolar bones and panorama mandibular index (PMI, represents as cortical thickness) were analysed statistically according to age and T score variables. Results: The radiographic density of alveolar bone of maxillary molar showed significant difference by age and femur T group. That of mandibular molar showed significant difference between femur T group. Panorama mandibular index showed significant difference between age groups. Conclusion: The radiographic density of alvealar bones was more dependent on age and femur T than lumbar T. Cortical thickness of mandible was correlated with increasing age.

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A correction method for objective seismic damage index of reinforced concrete columns

  • Kang, Jun Won;Lee, Jeeho
    • Computers and Concrete
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    • v.21 no.6
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    • pp.741-748
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    • 2018
  • In this paper, the sensitivity of a plastic-damage-based structural damage index on mesh density is studied. Multiple finite element meshes with increasing density are used to investigate their effect on the damage index values calculated from nonlinear finite element simulations for a reinforced concrete column subjected to cyclic loading. With the simulation results, this paper suggests a correction method for the objective damage index based on nonlinear regression of volumetric tensile damage ratio data. The modified damage index values are presented in the quasi-static cyclic simulation to show the efficacy of the suggested correction method.

Body Fat Percent and Serum Lipid Level of School Children by Obesity Index (대구지역(大邱地域) 일부(一部) 국민학교(國民學校) 아동(兒童)의 비만도별(肥滿度別) 체지방(體脂肪) 비율(比率)과 혈청지질치(血淸脂質値))

  • Kim, In-Sook;Lee, Kyeong-Soo;Kang, Pock-Soo
    • Journal of the Korean Society of School Health
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    • v.7 no.2
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    • pp.125-133
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    • 1994
  • This study was conducted to identify the relationship between body fat percent/serum lipid level and obesity index among school children. The study subjects were 277 boys and 266 girls aged between 10 and 11 years old in a selected elementary school in Taegu City. The survey was conducted for the period of two months from May 1 to June 30, 1993. A $R{\ddot{o}}hrer$index(weight/height3) was calculated for each individual as a measure of obesity. Three groups were classified as underweight($R{\ddot{o}}hrer$ index < 109), normal($109{\leq}$ $R{\ddot{o}}hrer$ index < 140), and overweight ($R{\ddot{o}}hrer$ index ${\geq}140$). As for the body fat percent, fat weight, lean body mass were measured by impedance fat, meter(Model SIF-891). Serum total cholesterol. high-density lipoprotein, and triglyceride were measured by automated clinical chemistry analyzer(Astra system). Obesity was found 18.1% in boys and 14.7% in girls. Body weight, fat percent, fat weight, and lean body mass were significantly different among three groups classified by $R{\ddot{o}}hrer$ index in both sexes. Serum total cholesterol, triglyceride, atherogenic index and T-CHO/HDL ratio were also significantly different among three groups in both sexes. Serum total cholesterol, low-density lipoprotein, trigylceride, atherogenic index of boys were positively correlated with height, weight. $R{\ddot{o}}hrer$ index, fat weight, lean body mass, and triglyceride. The negative correlation was found in high-density lipoprotein against height, weight, Rohrer index, fat percent, fat weight, lean body mass. Triglyceride and atherogenic index of the girls were positively correlated with height, weight, $R{\ddot{o}}hrer$ index, fat percent, fat weight, lean body mass. The negative correlation was found in high-density lipoprotein against height, weight, $R{\ddot{o}}hrer$ index, fat percent, fat weight, lean body mass. These findings suggest that the prevention of obesity and hyperlipidemia among school children is very important. Thus adoption of healthy life-style is strongly recommended in school health programs in order to prevent the obesity and hyperlipidemia.

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Bone Mineral Density, Body Mass Index, Stress, and Health Promotion Lifestyle of Female College Students (일 대학 여대생의 골밀도, 체질량지수, 스트레스 및 건강증진 생활양식)

  • Kim, Chun-Mi;Kim, Eun-Man
    • Research in Community and Public Health Nursing
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    • v.21 no.3
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    • pp.333-340
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    • 2010
  • Purpose: The purpose of this study was to examine the bone mineral density (BMD), body mass index (BMI), stress, and health promotion lifestyle of female college students and to assess relations among them. Methods: A total of 220 female college students were assessed through anthropometric measurements and bone mineral density test using quantitative ultrasound. In addition, the subjects were asked about stress and health promotion lifestyle with a self-rating questionnaire. Collected data were processed with the SPSS/WIN 12.0 program. Results: 1) Of the students, 67.8% had weight control experience. The percentage of the osteoporosis, osteopenia and normal groups were 2.8%, 53.5% and 43.8%, respectively, and the percentage of the underweight, normal and overweight groups according to BMI were 27.9%, 57.2% and 14.9%, respectively. 2) The levels of stress and health promotion lifestyle were 2.9 and 2.3, respectively. 3) There was a positive correlation between BMD and BMI (r=.196, p<.01). There was a negative correlation between stress and health promotion lifestyle (r=-.35, p<.01). 4) Weight control experience made negative effects on BMD and BMI. Conclusion: The findings of this study suggest the necessity of new health promotion programs to increase bone density of female college students. Stress management programs are also needed.

Correlation of Breast Tissue Density and Body Mass Index (유방조직의 밀도와 체질량지수와의 상관관계)

  • Yang, Jung-Hak;Lee, Taik-Jong
    • Archives of Plastic Surgery
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    • v.37 no.6
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    • pp.732-735
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    • 2010
  • Purpose: In performing breast reconstruction, making symmetrical breast is still a challenge. A precise estimate of the volume of the breast specimen is necessary to reconstruct a symmetrical and aesthetically pleasing breast. This study aims at finding out the relationship with breast tissue density and body mass index designed to apply for breast reconstruction. Methods: By using the Archimedes' principle, the authors calculated the volume of the breast specimen and drew a correlation between the density of breast specimen and BMI. From October 2002 to November 2004, this method was used on 197 patients to predict breast volume for TRAM flap reconstruction. Results: The mean density was 0.9954g/cc and had no correlation with BMI (p-value=0.069). There was no difference between denstiy of breast tissue after skin spared mastectomy and that of breast tissue after nipple spared mastectomy. Conclusion: These data will be helpful to predict the needed volume for breast reconstruction.

Application of the L-index to the Delineation of Market Areas of Retail Businesses

  • Lee, Sang-Kyeong;Lee, Byoungkil
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.3
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    • pp.245-251
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    • 2014
  • As delineating market areas of retail businesses has become an interesting topic in marketing field, Lee and Lee recently suggested a noteworthy method, which applied the hydrological analysis of geographical information system (GIS), based on Christaller's central place theory. They used a digital elevation model (DEM) which inverted the kernel density of retail businesses, which was measured by using bandwidths of pre-determined 500, 1000 and 5000 m, respectively. In fact, their method is not a fully data-based approach in that they used pre-determined kernel bandwidths, however, this paper has been planned to improve Lee and Lee's method by using a kind of data-based approach of the L-index that describes clustering level of point feature distribution. The case study is implemented to automobile-related retail businesses in Seoul, Korea with selected Kernel bandwidths, 1211.5, 2120.2 and 7067.2 m from L-index analysis. Subsequently, the kernel density is measured, the density DEM is created by inverting it, and boundaries of market areas are extracted. Following the study, analysis results are summarized as follows. Firstly, the L-index can be a useful tool to complement the Lee and Lee's market area analysis method. At next, the kernel bandwidths, pre-determined by Lee and Lee, cannot be uniformly applied to all kinds of retail businesses. Lastly, the L-index method can be useful for analyzing the space structure of market areas of retail businesses, based on Christaller's central place theory.

Developing Integrated Transportation Service Index for Encouraging Transit-oriented Development (TOD형 개발 촉진을 위한 통합교통서비스 지표의 개발)

  • Hwang, Kee Yeon;Shin, Sang Young;Cho, Yong Hak;Sohn, Kee Min
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.1D
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    • pp.1-10
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    • 2008
  • Recently, the Seoul Metropolitan Government (SMG) has initiated several urban redevelopment projects to revitalize the downtown well equipped for transit oriented development (TOD). Since, TOD should incur higher density development in our context, it has negative impacts on travel patterns, congestion, and urban environmental quality. The purpose of this study is to develop new transportation service index which can facilitate higher density TOD. This study includes relevant foreign case studies, the development of multimodal transportation index, and the impact analysis of TOD when it is applied in the downtown Seoul. In chapter III, it developed a so-called ITLOS, new multimodal transportation service index which shows the possibility of accommodating further development by integrating roadway service index with public transportation service index. The study sets ten policy scenarios by varying densities, and run the Seoul Congestion Management Model (SECOMM) to estimate the sustainable transportation impacts of TOD in the downtown. Travel speed index that only represents the availability of road capacity for development reveal that higher density development in the downtown can deteriorate traffic congestion while improving region-wide transportation level of service in Seoul. Also, it is proved that higher density development is more feasible when using ITLOS as the index because it considers not only available road capacity but subway capacity in the analysis area.

The Production Objectives and Optimal Standard of Density Control Using Stand Density Management Diagram for Pinus densiflora Forests in Korea (임분밀도관리도를 이용한 소나무림의 적정 임분밀도 관리 기준 및 수확목표)

  • Park, Joon-hyung;Jung, Su-Young;Yoo, Byung-oh;Lee, Kwang-Soo;Park, Yong-bae;Kim, Hyung-Ho
    • Journal of Korean Society of Forest Science
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    • v.106 no.4
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    • pp.457-464
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    • 2017
  • This study has utilized the stand density management diagram to devise an efficient management standard for the stand density for Pinus densiflora that secures the health of the stands and predicted the harvest goals. The appropriate stand control level was estimated by modeling the relationship of the relative yield index (Ry) to the ratio of slender trees within the stand through an exponential function; the coefficient of determination ($R^2$) was found to be 0.424 according to the estimation. The ratio of slender trees within the stand showed a tendency of rapid increase at a certain relative yield index; with this relational function, the appropriate Ry value of 0.84 was obtained. By estimating the curve of the Ry value 0.84, which was the appropriate stand density management level, as well as the height of dominant trees in the central region of Korea, the production objective for each site index was set. Assuming that the final age by the site indices ranged from 10 to 16 for the P. densiflora in central region of Korea, the number of production was estimated to be between 426 to 1,311 trees per ha. It was predicted that the production of medium-diameter logs larger than 30 cm in diameter is possible for the target DBH at a site index of more than 16; small-diameter logs larger than 20 cm in diameter for site indices 12 and 14 enabled, and small-diameter logs of less than 20 cm for site index 10.

Relationship between Tree Species Diversity and Carbon Stock Density in Moist Deciduous Forest of Western Himalayas, India

  • Shahid, Mohommad;Joshi, Shambhu Prasad
    • Journal of Forest and Environmental Science
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    • v.33 no.1
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    • pp.39-48
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    • 2017
  • With the growing global concern about climate change, relationship between carbon stock density and tree species has become important for international climate change mitigation programmes. In this study, 150 Quadrats were laid down to assess the diversity, biomass and carbon stocks in each of the forest ranges (Barkot Range, Lachchiwala Range and Thano Range) of Dehra Dun Forest Division in Doon Valley, Western Himalaya, India. Community level carbon stock density was analyzed using Two Way Indicator Species Analysis. Species Richness and Shannon Weiner index was correlated with the carbon stocks of Doon Valley. Positive and weak relationship was found between the carbon stock density and Shannon Weiner Index, and between carbon stock density and Species Richness.