• Title/Summary/Keyword: endogenous variables

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Dynamic Structural Equation Models of Activity Participation and Travel Behavior using Puget Sound Transportation Panel (Puget Sound Transportation Panel을 이용한 활동참여와 통행행동의 Dynamic SEM)

  • 최연숙;정진혁
    • Journal of Korean Society of Transportation
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    • v.20 no.6
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    • pp.129-140
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    • 2002
  • This paper develops a dynamic structural equation model, which captures relationships among socio-demographics, activity participation(i.e., time use) and travel behavior in consideration with time variation effects. The data used in developing the model are two waves(the year 1991 and 1992) from Puget Sound Transportation Panel (PSTP). which is surveyed in Puget Sound Region in United States. The PSTP is widely used in transportation behavior analysis and includes various information of traveler's socio-economic, travel patterns, and activity participation. In the model, we use 10 endogenous variables including activity participations and travel behaviors and 10 exogenous variables composed of time variant and invariant traveler's socio-demographic variables. The empirical model shows that strong relationships exist not only between socio-demographics and travel behavior, but between waves. We also confirm needs of panel data set to identify and understand time variation effects and travel behaviors.

Effectiveness of golf skills to average score in PGA (PGA 선수의 경기능력이 평균타수에 미치는 영향력)

  • Kim, Sae-Hyung;Lee, Jun-Woo;Lee, Mi-Sook
    • Journal of the Korean Data and Information Science Society
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    • v.23 no.3
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    • pp.505-514
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    • 2012
  • This study is for effectiveness of golf skills to average score using path analysis in Professional golf association. The variables in this study were that seven independent variable were driving accuracy, green in regulation, driving distance, sand save ratio, scrambling, putting average, and two endogenous variables were birdie average, bogey average, and dependent variable was the scoring average. To analyze these variables, path analysis was used through AMOS 18.0 program and Alpha level sets at.05. As the result, the final model had significant goodness-of-fit (GFI=.989, RMSEA=.044, TLI=.991, CFI=.998) and showed that green in regulation, driving distance, sand save ratio, scrambling, and putting average significantly affected average score directly. Especially, the scrambling was the highest affectation to average score and the sand save ratio was the lowest affectation to the average score.

Structural Equation Modeling of Self-Care Behaviors in Kidney Transplant Patients Based on Self-Determination Theory (자기결정성이론에 근거한 신장이식환자의 자가간호행위 구조모형)

  • Jeong, Hye Won;So, Hyang Sook
    • Journal of Korean Academy of Nursing
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    • v.48 no.6
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    • pp.731-742
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    • 2018
  • Purpose: The purpose of this study was to test a hypothesis explaining direct and indirect relationships among the factors affecting self-care behaviors of kidney transplant patients, based on self-determination theory. Methods: Data were collected from 222 outpatients with kidney transplantation. The endogenous and exogenous variables of the hypothetical model consisted of healthcare provider's autonomy support, duration after kidney transplantation, basic psychological need satisfaction, autonomous and controlled motivation, depression, and self-care behaviors. Collected data were analyzed using SPSS/WIN 24.0 and AMOS 24.0. Results: The hypothetical model demonstrated a good fit: RMSEA=.06, SRMR=.04, TLI=.94, CFI=.97. Statistically significant explanatory variables for the self-care behaviors of kidney transplant patients were duration after transplantation and basic psychological need satisfaction. Healthcare provider's autonomy support was indirectly significant, while autonomous motivation, controlled motivation and depression were not statistically significant for self-care behaviors. The variables accounted for 59.5% of the self-care behaviors of kidney transplant patients. Conclusion: It is necessary to develop an autonomy support program for healthcare providers to enhance the self-care behaviors of kidney transplant patients. Preventing the deterioration of self-care behaviors will be possible by conducting this program at one year and six years post-transplantation. In addition, the results suggest the need to developing personalized autonomy support programs for healthcare providers that can meet the basic psychological need satisfaction of kidney transplant patients.

Structural Equation Modeling of Advance Directive Intent among a Korean Group in their Middle-Age (한국 중년층의 사전연명의료의향 의도 구조모형)

  • Jung, Young-Mi
    • The Journal of Korean Society for School & Community Health Education
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    • v.22 no.1
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    • pp.55-72
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    • 2021
  • Objectives: The aim of this study was to construct and verify a structural equation model of advance directive intent among a Korean group in their middle-age. Methods: Data were collected between May 1 and 30, 2017, from 398 people. The endogenous and exogenous variables of the hypothetical model consisted of elderly parents' care burden, health status, attitude towards withdrawal of life sustaining treatment, advance directive efficacy, and advance directive intent. The collected data were analyzed using the SPSS/WIN 24.0 and Mplus 7.4. Results: The hypothetical model demonstrated a good fit: χ2=223.79(df=109, p<.001), CMIN/df=2.05 CFI=.96, TLI=.96, RMSEA=.05, SRMR=.06. Elderly parents' care burden and health status showed statistically significant direct effects with attitude toward withdrawal of life sustaining treatment(β=.17, p=.001; β=.21, p<.001) and advance directive efficacy(β=.11, p=.040; β=.19, p=.002), respectively. Attitude toward withdrawal of life sustaining treatment and advance directive efficacy showed statistically significant direct effects on advance directive intent(β=.15, p=.007; β=.48, p<.001). Elderly parents' care burden and health status had a significant indirect effect on advance directive intent through attitude toward withdrawal of life sustaining treatment(β=.01, p=.041; β=.05, p=.036) and advance directive efficacy(β=.06, p=.049; β=.16, p=.006), respectively. The variables accounted for 26.1% of advance directive intent of the Korean group in their middle-age. Conclusion: It is necessary to develop an advance directive education program based on variables affecting advance directive intent for individuals in their middle-age.

Non-recursive Path Model Analysis on the Relationship between Perceived Safety Management Activities and Safety of Construction Sites (건설현장의 지각된 안전관리 활동과 안전성과의 관계에 대한 비재귀 경로모형분석)

  • Yong Hoon Kim
    • Journal of the Society of Disaster Information
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    • v.18 no.4
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    • pp.786-794
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    • 2022
  • In construction sites, effective preventive safety management is required beyond post-processing safety management. Purpose: The purpose of this study is to present a model and analyze the relationship between safety management activities, safety culture key elements, safety, unsafe behavior management, and safety for autonomous and preventive safety management. Method: The relationship was analyzed by applying the survey data to the structural equation, and the path to safety outcomes from exogenous variables was explored and major issues were presented by interpreting the part suggested by the hypothesis verified by the analysis results. Result: As a result of analyzing the preliminary model and the path model, the appropriate model fit was confirmed, and the significant effect of exogenous variables on endogenous variables was confirmed. Conclusion: It is judged that it can contribute to continuously improving safety performance before safety accidents occur through safety management activities, safety and unsafe behavior management, and management of key elements of safety culture.

Structural Model on Hypertensive Patient's Lifestyle and Quality of Life (고혈압 환자의 생활양식과 삶의 질에 관한 구조 Model)

  • Lee Jong Ryol;Park Chun Man
    • Health Policy and Management
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    • v.14 no.3
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    • pp.66-96
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    • 2004
  • This study was intended to describe the hypertensive patient's lifestyle and quality of life by creating a hypothetic model on the lifestyle and quality of life and by examining a causeand effect relationship, and to contribute to countermeasures for practicing their lifestyle and improving the quality of life through creating a predictable model. Exogenous variable($\xi$) of hypothetic model in this study composed of a family support, hypertension knowledge, perceived benefit and toughness. Endogenous variable($\eta$) composed of self-esteem, perceived health state, depression, lifestyle and quality of life. There were 6 measured variables for exogenous variable(x). There were 9 measured variables(y) for endogenous variable. Also, there was error variable ($\delta,\;\epsilon$) of an individual. The survey was conducted for 207 hypertensive parents who received an out-patient service for 3 weeks from September 15, 2003 to October 3, 2003 after diagnosing as hypertension from 2 general hospitals in Daegu. As the conformance of hypothetic model in this study, there were $x^2$= 155.81, standard $x^2$ ($x^2$/df)=2.32, GFI=0.003, NFI=0.971, CFI=0.982, and RMSEA=0.080. Generally, the hypothetic model and actual data were well coincided. The higher the hypertension knowledge was(t=6.030), the higher the perceived benefit was(t=9.429), the higher the toughness was(t=2.783), and the higher the perceived health state was(t=2.282), the higher the lifestyle was. However, the degree of depression (t=-0.038), family support(t=1.161), and self-esteem(t=0.518) was not affected. The higher the family support was(t=10.476), the higher the self-esteem was(t=7.244), the higher the perceived health state was(t=6.996), the lower the degree of depression was(t=-2.044), and the higher the practice degree of lifestyle was(t=3.315), the higher the quality of life was. However, the toughness(t=1.672) didn't have a significant influence on the quality of life. It was modified to increase the model conformance and gain a conscious model As the result of model revision, for the model conformance, there were $x^2$= 118.43, standard $x^2$=1.69, GFI=0.923, NFI=0.976, CFI=0.982, and RMSEA=0.078. As the revised model showed the better conformance than hypothetic model, it seemed to be more suitable model. In the revised model, the perceived benefit(t=9.440) affected the lifestyle in the revised model. Then, the lifestyle was influenced by hypertension knowledge(t=6.139), toughness (t=2.757), family support(t=2.078), perceived health state(t=1.962) in the order. As a factor which affected the quality of life, there were the family support(t=l0.46l), self-esteem(t=7.368), perceived health state(t=6.989), lifestyle(t=3.316), toughness(t=2.584), and depression(t=-1.968) in the order. It showed the significant effect.

Evaluating the Multi-Period Management Efficiency of Domestic Online-Shopping Companies (DEA와 Malmquist 생산성지수를 이용한 우리나라 온라인쇼핑업체의 다기간 경영 효율성 분석)

  • Ma, Jin-Hee;Ja, Yoon-Ho;Ahn, Young-Hyo
    • Journal of Distribution Science
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    • v.13 no.4
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    • pp.45-53
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    • 2015
  • Purpose - Online shopping enables consumers to conveniently purchase products irrespective of the time and place. As a result, several online shopping companies have emerged to cater to this growing market and, therefore, the competition among them has become increasingly intense. This paper evaluates the comparative efficiency of online shopping companies for a multi-year period (2009-2013), in order to help online shopping managers identify major drivers for enhancing management efficiency and the subsequent competitiveness. Research design, data, and methodology - The researchers collected the data from 2009 to 2013 from the distribution yearbook. This paper analyzes the marketability (sales figures), profitability (business profits), and management conditions (net profits) of domestic online shopping enterprises by incorporating information on human resources (number of employees) and material resources (total assets and capital). Therefore, the number of employees, total assets, and capital are selected as input variables, and sales figures, business profits, and net profits as the output variables. In this study, Data Envelopment Analysis (DEA) was used to measure the comparative efficiency of domestic online shopping companies. In addition, the Malmquist Productivity Index was used to evaluate the trend of change of Decision Making Units' (DMUs') efficiency for a multi-year period. Results - First, as of 2013, Interpark (2.415) was found to be the most efficient online shopping enterprise, followed by Aladdin Communications (2.117), Hyundai Home shopping (1.867), Home&Shopping (1.176), NS Home shopping (1.170), Commerce Planet (1.126), CJ O Shopping (1.105), Ebay Korea (1.088), and GS Home Shopping (1.051). Second, this study recognizes how the management efficiency has changed for the period 2009-2013. Third, the lesser the capital and employees, the more are the net profits, and the better is the management efficiency of domestic online shopping companies. Lastly, the productivity of such companies is influenced by endogenous factors rather than exogenous factors such as shifts in business environment and technological advances. Conclusions - DHC Korea influenced various distribution channels to reach customers through the Internet. Consequently, this helped in increasing the awareness about its products, in addition to an increase in sales. These achievements can be attributed to the characteristics of online shopping companies. Although it is easy for these companies to suggest goods for one-off purchases, they however have difficulties in retaining customers. Overcoming this challenge can be one of the ways to benchmark a successful case of an efficient company. For example, an online shopping company can attract customers by developing a corresponding mobile application as a convenient way to shop online. Additionally, they can satisfy customers by quick delivery of purchased products, which is possible by building an effective logistics network. Our study indicates that the productivity of an online shopping company was influenced by endogenous factors driven by improvements in managerial practices rather than exogenous factors. Accordingly, online shopping companies should adopt strategies to improve their operational efficiency rather than sales volume-oriented management.

Comparative Analysis on Efficiency and Productivity for Korea, Japan and Global Parcel Delivery Companies (한국, 일본, 글로벌 택배기업의 효율성 및 생산성 비교 분석)

  • Ma, Jin-Hee;Ahn, Young-Hyo
    • Journal of Distribution Science
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    • v.14 no.3
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    • pp.73-83
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    • 2016
  • Purpose - The parcel delivery service(courier) industry all over the world has been expanding its market so far, but its growth has been declining in recent years. In this situation, most parcel delivery companies are having trouble with managing themselves because of the pressure from the customer to increase service level and decrease the rate. The purpose of this study is to provide ways to improve competitive advantages of the parcel delivery service industry by evaluating the multi-period operating efficiency of Korea, Japan and global service providers. Research design, data, and methodology - The data for the period of 2011 to 2014 were collected from the annual reports published by parcel delivery companies. In this study, we analyze the marketability (revenue), profitability (operating profits), and management conditions (net profits) of parcel service companies by combining information on human resources (number of employees) and material resources (total assets and equity). Therefore, the number of employees, total assets, and equity are selected as input variables, and revenue, operating profits, and net profits as the output variables. In this study, DEA (Data Envelopment Analysis) is used to measure the comparative efficiency and MPI (Malmquist Productivity Index) is used to analyze the trend of change of the efficiency for a multi-year period. Results - The operational efficiency scores of medium-sized parcel delivery companies in Korea are higher than other larger competitors such as Korean, Japan and Global larger companies. As of 2014, Logen(1.878) was found to be the most efficient parcel delivery enterprise, followed by KGB (1.224), and Kyoungdong(1.002). Otherwise, Hanjin(0.235), CJ(0.262), Hyundai Logistics(0.657), DHL(0.611), UPS(0.766), FedEx(0.498), TNT(0.350), Yamato(0.762) and Sagawa(0.520), larger sized companies, were done inefficiently. The productivity of parcel delivery companies is influenced by endogenous factors as well as exogenous ones such as changes in business environment and technological advances. Conclusions - Korean medium-sized companies have relatively high efficiency scores in operation. That is why they still survive the competitive market in Korea where market restructuring on the industry has been expected to be conducted for many years. The reason why medium-sized couriers had higher efficient scores than larger couriers is that most of couriers spend more operating expenses versus unit price of delivery which is the amount of money that is needed in order to send a package by parcel service. So the delivery unit price must be taken into account by all the expenses associated with the cost of fuel, labor and maintenance expenses for facilities, etc. therefore, the unit price must be increased to strengthen business competitive power. In order for the industry to have more competitive advantage, the companies need to make profits by increasing demand volume and raising the delivery rate to provide high-quality delivery service to customers. And both endogenous and exogenous change must take precedence in order to strengthen their competitiveness.

A Model for Post-Traumatic Stress and Burnout in Firefighters (소방대원의 출동충격스트레스와 소진에 관한 구조모형)

  • Choi, Eun-Sook
    • The Korean Journal of Emergency Medical Services
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    • v.5 no.1
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    • pp.147-164
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    • 2001
  • The purpose of this study was to examine the hypothetical model designed to explain the post-traumatic stress and burnout in firefighters. Six exogenous variables such as career, control, impact mobilization frequency, life event, work burden, social support, and four endogenous variables, eg., mobilization impact, coping, post-traumatic stress, burnout were considered for the study. The target population for the distribution of the questionnaire was 428 firefighters in Daejeon, Chungnam Province, Seoul and Kyonggi Province. The data was collected about five weeks, July 12-August 25, 1999. The survey instrument was 8 control items by Seo(1995), 10 life event items by Brugha and Cragg(1990), 20 work burden items by Choi(2000), 12 social support items by Park(1985), post-traumatic stress of 17 items by Foa et al.(1998) and 45 items by Kang(1997). The reliability of the survey instrument and the cronbach's alpha was .62 - .93 level. SAS PC Program and LISREL 8.12a program were used for descriptive statistics and linear structural relationship(LISREL) modeling. Based on the data collected, the following results were obtained. 1. The overall fit of the hypothetical model to the data was good (${\chi}^2=54.65$ [df=17, p=0.000007], RMSEA=0.07, standardized RMR=0.03, GFI=0.98, AGFI=0.91, NFI=0.90, NNFI=0.75). 2. After considering statistical significance and theoretical meaningfulness of paths of the model, a modified model was sought. Compared to the hypothetical model, the modified model has become parsimonious and had a better fit to the data(${\chi}^2=55.90$ [df=20, p=0.0003], RMSEA=0.06, standardized RMR=0.03, GFI=0.98, AGFI=0.93, NFI=0.90, NNFI=0.80). 3. The results of statistical testing of hypotheses were as follows: (1) Work burden, career had a significantly direct effect on mobilization impact. These variables explained 9% of the total variance of mobilization impact. (2) Control, social support, work burden, mobilization impact had a significantly direct effect on coping. These variables explained 15% of the total variance of coping. (3) Control, work burden, social support, coping had a significantly direct effect on post-traumatic stress. These variables explained 49% of the total variance of post-traumatic stress. (4) Coping, post-traumatic stress had a significantly direct effect on burnout. These variables explained 60% of the total variance of burnout.

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A Structural Model for Health Promotion and Life Satisfaction of Life in College Students in Korea (대학생들의 건강증진행위와 삶의 만족도에 대한 구조모형)

  • Hong, Youn-Lan;Yi, Ga-Eon;Park, Hyun-Sook
    • Research in Community and Public Health Nursing
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    • v.11 no.2
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    • pp.333-346
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    • 2000
  • The purpose of this study was designed to test and develope the structural model that explains health promoting behaviors among college students in Korea. The hypothetical model was constructed on the Pender's Health promotion Model(l996) and the inclusion of some influential factors for life satisfaction. The conceptual framework was built around eight constructs. Exogenous variables included in the model were self-esteem, perceived health status, self-efficacy, internal locus of control, chance locus of control. powerful other locus of control. Endogenous variables were health promotion behaviors and life satisfaction. The results are as follows; 1. The overall fit of the hypothetical model to the data was moderate <$x^2$=4.18(df=11. p=0.041), GFI= 0.99, AGFI= 0.76, RMR= 0.019, CFI= 0.99, CN= 248.50> 2. Path and variable of the model were modified by considering both its theoretical implication and statistical significance of parameter estimates. Compared to the hypothetical model. the revised model has become parsimonious and had a better fit to the data expected in a chi-square value <$x^2$=8.43( df= 16, p=0.21), GFI= 0.99, AGFI= 0.92., RMR= 0.024, CFI= 0.99, CN= 312.01> 3. Some of the predictive factors. especially self efficacy. self esteem. powerful others locus of control. perceived health status revealed the direct effects on health promoting behaviors. Of these variables. self-efficacy was the most signigicant factor. These predictive variables of health promoting behaviors explained 59% of total variances in the model. 4. Health promoting behaviors, self-esteem. and perceived health status revealed direct effect on the life satisfaction. Self-efficacy was identified as an important variable that contributed indirectly to improve life satisfaction by enhancing health promoting behaviors. These predictive variables of life satisfaction explained 42% of total variances in the model. In conclusion. the derived model in this study is considered appropriate in explaining and predicting health promoting models and life satisfaction among college students in Korea and could effectively be used as a reference model for further studies by suggesting a direction in health promoting nursing practices.

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