• Title/Summary/Keyword: 다중선형 및 비선형회귀분석

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Influence Factors of Typical Real Estate Development Projects (부동산 개발사업의 유형별 투자결정요인 분석)

  • Lee, Taek-Soo;Lee, Joo-Hyung
    • The Journal of the Korea Contents Association
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    • v.13 no.1
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    • pp.456-466
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    • 2013
  • The most important thing to develop real estate asset would be a feasibility study. To secure feasibility of development projects, reducing and minimizing the cost of land and construction also would be the important thing. To analyze optimal land-value for real estate development projects, I have collected 204 balance sheets of development projects in South Korea. With the help of statistical technology, I could have selected useful data from those balance sheets. After detailed analysis of statistical data, I could have reached conclusion that the most important factor to earning rate would be land cost per unit ground area under the constraint of given sale price. So far the main pattern of feasibility study of development projects was land cost and construction cost. However, by this study, I have found a new fact that construction cost has little effect to earning rate and land cost per unit ground area is the most effect to earning rate especially in residential facilities rather than commercial ones.

Effect of Health Behaviors, Dietary Habits, and Psychological Health on Metabolic Syndrome in One-Person Households Among Korean Young Adults (1인가구 청년의 건강행태, 식습관 및 심리적 건강이 대사증후군에 미치는 영향)

  • Kim, Ahrin
    • Journal of Digital Convergence
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    • v.16 no.7
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    • pp.493-509
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    • 2018
  • This study was performed to compare the effects of health behaviors, dietary habits, and psychological health on metabolic syndrome (MS) between young adults living in one-person households (OPHs) and multiple-person households (MPHs). The data from the Korean National Health and Nutrition Examination Survey (KNHANES), which was conducted in 2014 and 2016 were used. The subjects were 2,682, who were 20 to 39 years old. The data were analyzed using complex sample Rao-Scott ${\chi}^2-tests$, t-tests, and multiple logistic regression using SPSS 23.0 software. Sex, age, obesity, and subjective health status were associated with MS in young adults living in either OPHs or MPHs. Breakfast consumption frequency, eating alone, food label use, stress, and depression were associated with MS only in young adults living in OPHs. Thus, these differentiated risk factors of MS should be considered, when health promotion strategies and interventions are planned for young adults living in OPHs. Also, further studies are needed to evaluate the effectiveness of the strategies or interventions.

The Relationship between Physical Characteristics and Walking Ability in Elderly: A Cross-Sectional Study (노인들의 보행 능력과 신체적인 특성 간의 상관관계: 단면 연구)

  • Park, Mi-Hee;Park, Hyun-Ju;Oh, Duck-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.6
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    • pp.2664-2671
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    • 2012
  • This study aimed to investigate the relationship between physical characteristics and walking ability in the elderly population. Subjects were 77 elderly (38 men and 39 women) who are capable of walking independently with and without walking aids. Correlation and stepwise multiple linear regression analyses were used to analyze the relationship between physical characteristics (age, gender, height, weight, body mass index, muscle mass, waist/hip ratio, heart rate, vital capacity, flexibility, maximum oxygen consumption, one-leg standing time, and strength of knee flexor and extensor) and walking velocity of subjects. Age, height, vital capacity, one-leg standing time, and strength of knee flexor and extensor showed significant correlations with walking velocity of subjects (p<.05). Further, the strength of knee flexor explained 27% of the variance, and up to 32% of the walking velocity could be explained when the strength of knee extensor were added to the model. The findings suggest that walking velocity of elderly depends on the strength of lower limb's strength and a variety of physical characteristics.

Corporate Default Prediction Model Using Deep Learning Time Series Algorithm, RNN and LSTM (딥러닝 시계열 알고리즘 적용한 기업부도예측모형 유용성 검증)

  • Cha, Sungjae;Kang, Jungseok
    • Journal of Intelligence and Information Systems
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    • v.24 no.4
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    • pp.1-32
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    • 2018
  • In addition to stakeholders including managers, employees, creditors, and investors of bankrupt companies, corporate defaults have a ripple effect on the local and national economy. Before the Asian financial crisis, the Korean government only analyzed SMEs and tried to improve the forecasting power of a default prediction model, rather than developing various corporate default models. As a result, even large corporations called 'chaebol enterprises' become bankrupt. Even after that, the analysis of past corporate defaults has been focused on specific variables, and when the government restructured immediately after the global financial crisis, they only focused on certain main variables such as 'debt ratio'. A multifaceted study of corporate default prediction models is essential to ensure diverse interests, to avoid situations like the 'Lehman Brothers Case' of the global financial crisis, to avoid total collapse in a single moment. The key variables used in corporate defaults vary over time. This is confirmed by Beaver (1967, 1968) and Altman's (1968) analysis that Deakins'(1972) study shows that the major factors affecting corporate failure have changed. In Grice's (2001) study, the importance of predictive variables was also found through Zmijewski's (1984) and Ohlson's (1980) models. However, the studies that have been carried out in the past use static models. Most of them do not consider the changes that occur in the course of time. Therefore, in order to construct consistent prediction models, it is necessary to compensate the time-dependent bias by means of a time series analysis algorithm reflecting dynamic change. Based on the global financial crisis, which has had a significant impact on Korea, this study is conducted using 10 years of annual corporate data from 2000 to 2009. Data are divided into training data, validation data, and test data respectively, and are divided into 7, 2, and 1 years respectively. In order to construct a consistent bankruptcy model in the flow of time change, we first train a time series deep learning algorithm model using the data before the financial crisis (2000~2006). The parameter tuning of the existing model and the deep learning time series algorithm is conducted with validation data including the financial crisis period (2007~2008). As a result, we construct a model that shows similar pattern to the results of the learning data and shows excellent prediction power. After that, each bankruptcy prediction model is restructured by integrating the learning data and validation data again (2000 ~ 2008), applying the optimal parameters as in the previous validation. Finally, each corporate default prediction model is evaluated and compared using test data (2009) based on the trained models over nine years. Then, the usefulness of the corporate default prediction model based on the deep learning time series algorithm is proved. In addition, by adding the Lasso regression analysis to the existing methods (multiple discriminant analysis, logit model) which select the variables, it is proved that the deep learning time series algorithm model based on the three bundles of variables is useful for robust corporate default prediction. The definition of bankruptcy used is the same as that of Lee (2015). Independent variables include financial information such as financial ratios used in previous studies. Multivariate discriminant analysis, logit model, and Lasso regression model are used to select the optimal variable group. The influence of the Multivariate discriminant analysis model proposed by Altman (1968), the Logit model proposed by Ohlson (1980), the non-time series machine learning algorithms, and the deep learning time series algorithms are compared. In the case of corporate data, there are limitations of 'nonlinear variables', 'multi-collinearity' of variables, and 'lack of data'. While the logit model is nonlinear, the Lasso regression model solves the multi-collinearity problem, and the deep learning time series algorithm using the variable data generation method complements the lack of data. Big Data Technology, a leading technology in the future, is moving from simple human analysis, to automated AI analysis, and finally towards future intertwined AI applications. Although the study of the corporate default prediction model using the time series algorithm is still in its early stages, deep learning algorithm is much faster than regression analysis at corporate default prediction modeling. Also, it is more effective on prediction power. Through the Fourth Industrial Revolution, the current government and other overseas governments are working hard to integrate the system in everyday life of their nation and society. Yet the field of deep learning time series research for the financial industry is still insufficient. This is an initial study on deep learning time series algorithm analysis of corporate defaults. Therefore it is hoped that it will be used as a comparative analysis data for non-specialists who start a study combining financial data and deep learning time series algorithm.

Influence on Enlisted Soldiers' Health behavior, Body-shape perception, and Weight control toward the BMI change (현역병의 건강행태, 주관적 체형인식, 체중조절 활동이 BMI 변화에 미치는 영향)

  • Lee, Hyun-Ju
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.3353-3360
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    • 2015
  • This study was conducted to identify the BMI of enlisted soldiers, to understand the difference between their BMI and that of other men in their age group, and to identify the influence factors of enlisted soldiers' BMI change. The survey has been conducted self-evaluation questionnaire from 23 Feb. 2009 to 31 Mar. 2009 from 4 different forces as methods. Independent-sample T-test, chi-square test and multiple linear regression analysis were used for statistical analysis from 301 collected data. As a result of surveying enlisted soldiers' BMI, their obesity rate 18.6% was lower than 22.1% of other men in their age group. In terms of health behavior, the underweight&normal weight group(2.39) showed higher diet score than the overweight group(2.13), showing that the underweight&normal weight group ate relatively slowly, less spicy and less sweet food compared to the overweight group. The overweight group(2.25) showed lower satisfaction with their body type than the underweight&normal weight group(2.98), while the overweight group(4.01) showed a significantly higher score than the underweight&normal weight group(3.37) for weight control activity. The influence factors of BMI change were diet habit, subjective perception of body type, and weight control activity. In order to improve of enlisted soldiers' BMI, it would be necessary to improve the food service and the snack bars for interventional control of food that influence obesity, rather than personal effort, in addition, education for right body-shape perception and encouraging on weight control activity.

Cost Prediction Models in the Early Stage of the Roadway Planning and Designbased on Limited Available Information (가용정보를 활용한 기획 및 설계초기 단계의 도로 공사비 예측모델)

  • Kwak, Soo-Nam;Kim, Du-Yon;Kim, Byoung-Il;Choi, Seok-Jin;Han, Seung-Heon
    • Korean Journal of Construction Engineering and Management
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    • v.10 no.4
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    • pp.87-100
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    • 2009
  • The quality of early cost estimates is critical to the feasibility analysis and budget allocation decisions for public capital projects. Various researches have been attempted to develop cost prediction models in the early stage of a construction project. However, existing studies are limited on its applicability to actual projects because they focus primarily on a specific phase as well as utilize restricted information while the amount of information collectable differs from one another along with the project stages. This research aims to develop two-staged cost estimation model for the schematic planning and preliminary design process of a construction projects, considering the available information of each phase. In the schematic planning stage where outlined information of a project is only available, the Case-Based Reasoning model is used for easy and rapid elicitation of a project cost based on the extensive database of more than 90 actual highway construction projects. Then, the representing quantity-based model is proposed for the preliminary design stage where more information on the quantities and unit costs are collectable based on the alternative routes and cross-sections of a highway project. Real case studies are used to demonstrate and validate the benefits of the proposed approach. Through the two-stage cost estimation system, users are able to hold a timely prospect to presume the final cost within the budge such that feasibility study as well as budget allocation decisions are made on effectively and competitively.

Associations between Characteristics of Green Spaces, Physical Activity and Health - Focusing on the Case Study of Changwon City - (공원녹지의 특성과 신체활동 및 건강의 상호관련성 - 창원시를 대상으로 -)

  • Baek, Su-Kyeongq;Park, Kyung-Hun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.3
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    • pp.1-12
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    • 2014
  • Urban Green space takes charge of the important role for the physical activity and promotion of health to the residents. Therefore, this study is trying to examine the relationship between the various characteristics of green space and green space usage for physical activity and health promotion. A questionnaire survey was conducted to obtain the information about patterns of green space usage and perceived neighborhood environments for the residents living in Changwon-si, Gyeongsangnam-do(n=541). Geographic Information System(GIS) was used to construct spatial data about green space accessibility and physical neighborhood environments. A Multiple Linear Regression model was used to examine the association between the characteristics of green space and physical activity, perceived health status and BMI(Body Mass Index). The study results revealed that the residents' physical activities are positively and directly influenced by the number of available public parks and green spaces in the vicinity(${\leq}200m$). The frequency at which residents witness others exercising nearby or the perceived abundance of low-cost gym facilities also factor as positive influences. The closer to the park, the higher the number of parks and area of green spaces, the more comfortable the walk thereto and the denser the neighboring residential area distribution, the perceived health level was found to be the more positively influenced. Further, it was verified that BMI is correlated with the number of public parks and green spaces within 400 m of the resident's home as well as the safety of walkways, the density of neighboring residential areas, the ratio of road, and the density of crosswalk. The significant multiple regression models between the characteristics of green spaces and physical activities and perceived health level were extracted within the significance level of 10%. This study will contribute to provide better understanding the ways in which green space and neighborhood characteristics are associated with physical activity and health. The result of this research will be available in the landscape architecture plan aimed at improving the use of green space for physical activity and reducing obesity.

Associations of serum 25(OH)D levels with depression and depressed condition in Korean adults: results from KNHANES 2008-2010 (한국 성인의 혈청 25(OH)D 수준과 우울증 및 우울증상 경험과의 연관성: 국민건강영양조사 2008-2010 분석 결과)

  • Koo, Sle;Park, Kyong
    • Journal of Nutrition and Health
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    • v.47 no.2
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    • pp.113-123
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    • 2014
  • Purpose: Vitamin D has been known to play an important role in the central nervous system and brain functions in the human body, and cumulative evidence has shown that vitamin D deficiency might be linked with various mental health conditions. Epidemiologic studies have shown that vitamin D deficiency may be associated with higher risk of depression in the US and European populations. However, limited information is available regarding the association between vitamin D status and depression in the Korean population. The objective of this study was to examine the associations between vitamin D levels and prevalence of depression. Methods: We conducted a cross-sectional analysis using nationally representative data from the 2008-2010 Korean National Health and Nutrition Examination Survey from which serum 25-hydroxyvitamin D concentrations were available. A total of 18,735 adults who had available demographic, dietary, and lifestyle information were included in our analysis. We defined "depression" with a diagnosis by a physician. "Depressed condition" was defined as having feelings of sadness or depression without diagnosis by a physician. Results: The prevalence of depression was 1.63% and 5.43% in Korean men and women, respectively; 12.5% of men and 26.1% of women were defined as the group having depressed conditions. In multivariate logistic regression models, no significant associations were observed between vitamin D status and prevalence of depression or depressed conditions in Korean men and women. Conclusion: We found no association between vitamin D insufficiency and depression/depressed conditions in Korean adults. Future large prospective studies and randomized controlled trials are needed to confirm this relationship.

Analysis on the Determinants of Land Compensation Cost: The Use of the Construction CALS Data (토지 보상비 결정 요인 분석 - 건설CALS 데이터 중심으로)

  • Lee, Sang-Gyu;Seo, Myoung-Bae;Kim, Jin-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.10
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    • pp.461-470
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    • 2020
  • This study analyzed the determinants of land compensation costs using the CALS (Continuous Acquisition & Life-Cycle Support) system to generate data for the construction (planning, design, building, management) process. For analysis, variables used in the related research on land costs were used, which included eight variables (Land Area, Individual Public Land Price, Appraisal & Assessment, Land Category, Use District 1, Terrain Elevation, Terrain Shape, and Road). Also, the variables were analyzed using the machine learning-based Xgboost algorithm. Individual Public Land Price was identified as the most important variable in determining land cost. We used a linear multiple regression analysis to verify the determinants of land compensation. For this verification, the dependent variable included was the Individual Public Land Price, and the independent variables were the numeric variable (Land Area) and factor variables (Land Category, Use District 1, Terrain Elevation, Terrain Shape, Road). This study found that the significant variables were Land Category, Use District 1, and Road.

CO2 net atmospheric flux estimation and influence factors analysis in a stratified reservoir (성층화된 저수지에서 CO2 NAF 산정 및 영향 인자 분석)

  • Park, Hyung Seok;Chung, Se Woong;Lee, Eun Ju
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.73-73
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    • 2019
  • 지구 표면의 약 2%에 해당하는 담수에서 육상계 전체가 흡수하는 탄소의 50%가 배출되며, 이는 토양표면에서 배출되는 탄소량에 비해 더 큰 수치로 전 지구적 탄소순환 해석에 중요한 역할을 한다. 특히, 내륙수역과 대기의 경계면에서 $CO_2$ 이동은 전 지구적 탄소순환의 중요한 구성요소로 평가되고 있다. 호수와 저수지 같은 담수 저류시설은 육상에서 기인한 탄소의 운송 및 처리 역할을 한다. 하지만, 저수지에서 온실가스배출량을 평가할 수 있는 명확한 방법론이 부족하며, 전지구 규모 GHGs배출량에 대한 추정에 대한 불확실성이 상당히 큰 상황이다. 본 연구에서는 몬순기후대에 위치한 인공저수지를 대상으로 보다 신뢰도있는 온실가스 배출량 추정을 위해 $CO_2$ NAF 산정하고, 산정에 영향을 미치는 인자들을 분석 하였다. 분석을 위해 $CO_2$ NAF 산정에 필요한 수리 및 수질 인자들을 2017년부터 2018년까지 수집하고, 기초통계량 및 상관분석을 실시하였다. 또한, 주성분분석(PCA) 및 다중선형회귀모델(MLR)과 랜덤포레스트(RF) 기법을 사용해 변수 중요도를 평가하였으며, $CO_2$ NAF 산정 주요인자인 기체교환 계수를 경험적 모델 3종(Cole and Caraco, Crusius, Vachon), 표면갱신형 모델 4종(Heiskanen, Maclntyre, Read, Soloviev)을 비교, 검토하였다. 조사기간 동안 기체교환계수 산정 결과 Crusius 모델 예측값이 평균 $0.342(0.047{\sim}4.323)cm\;hr^{-1}$으로 검토한 모델중 가장 낮은 평균값을 보였으며, Heiskane 모델이 $2.135(0.337{\sim}5.152)cm\;hr^{-1}$으로 가장 큰 평균값을 보였다. 대상 수체는 연주기로 완전혼합되며 수온성층이 약화되는 시기에 저수지 표층 아래에 축적된 탄소가 표층으로 전달되어 높은 수준의 p$CO_2$를 보이며, 수표면에 큰 난류 강도가 작용하는 기간에 대기중으로 배출(pulse emission) 기작이 나타난다. NAF 산정결과 경험적 모델의 NAF값($-1246.0{\sim}6510.3mg-CO_2m^{-2}day^{-1}$)은 표면갱신형 모델 NAF값($-1436.1{\sim}8485.7mg-CO_2m^{-2}day^{-1}$)보다 낮은 수준을 보였으며, 풍속의 함수만을 이용하는 경험적 모델보다 부력 플럭스와 난류 혼합의 영향을 고려하는 Macintyre, Heiskanen모델이 성층 저수지의 $CO_2$ NAF 산정에 적합한 것으로 나타났다. $CO_2$ NAF 산정의 주요인자로 MLR모델은 Tw, EC, pH, Chla, TOC, Alk, RF모델은 EC, DO, TOC가 중요 변수로 평가되었다. PCA 분석결과, 수온이 낮고 성층이 약화되며 pH가 낮은 상태에서 NAF가 큰 것으로 나타났다.

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