• Title/Summary/Keyword: Model Equation

Search Result 10,151, Processing Time 0.036 seconds

Carbon stocks and factors affecting their storage in dry Afromontane forests of Awi Zone, northwestern Ethiopia

  • Gebeyehu, Getaneh;Soromessa, Teshome;Bekele, Tesfaye;Teketay, Demel
    • Journal of Ecology and Environment
    • /
    • v.43 no.1
    • /
    • pp.43-60
    • /
    • 2019
  • Background: Tropical montane forests played an important role in the provision of ecosystem services. The intense degradation and deforestation for the need of agricultural land expansion result in a significant decline of forest cover. However, the expansion of agricultural land did not completely destruct natural forests. There remain forests inaccessible for agricultural and grazing purpose. Studies on these forests remained scant, motivating to investigate biomass and soil carbon stocks. Data of biomass and soils were collected in 80 quadrats ($400m^2$) systematically in 5 forests. Biomass and disturbance gradients were determined using allometric equation and disturbance index, respectively. The regression modeling is employed to explore the spatial distribution of carbon stock along disturbance and environmental gradients. Correlation analysis is also employed to identify the relation between site factors and carbon stocks. Results: The result revealed that a total of 1655 individuals with a diameter of ${\geq}5cm$, representing 38 species, were measured in 5 forests. The mean aboveground biomass carbon stocks (AGB CS) and soil organic carbon (SOC) stocks at 5 forests were $191.6{\pm}19.7$ and $149.32{\pm}6.8Mg\;C\;ha^{-1}$, respectively. The AGB CS exhibited significant (P < 0.05) positive correlation with SOC and total nitrogen (TN) stocks, reflecting that biomass seems to be a general predictor of SOCs. AGB CS between highly and least-disturbed forests was significantly different (P < 0.05). This disturbance level equates to a decrease in AGB CS of 36.8% in the highly disturbed compared with the least-disturbed forest. In all forests, dominant species sequestrated more than 58% of carbon. The AGB CS in response to elevation and disturbance index and SOC stocks in response to soil pH attained unimodal pattern. The stand structures, such as canopy cover and basal area, had significant positive relation with AGB CS. Conclusions: Study results confirmed that carbon stocks of studied forests were comparable to carbon stocks of protected forests. The biotic, edaphic, topographic, and disturbance factors played a significant variation in carbon stocks of forests. Further study should be conducted to quantify carbon stocks of herbaceous, litter, and soil microbes to account the role of the whole forest ecosystem.

Structural Relationship among Self Leadership, Social Support and School Adjustment Impacting on Academic Achievement of University Students - Focusing on the Case of S University (학업성취에 영향을 미치는 셀프리더십 및 사회적지지와 대학생활적응과의 구조적 관계 - S대학교 대학생 사례를 중심으로)

  • Lee, Eun-jung;Song, Young-soo
    • Journal of vocational education research
    • /
    • v.37 no.6
    • /
    • pp.63-83
    • /
    • 2018
  • The purpose of this study is to identify the main factors helping university students sucessfully adapt to campus life and achieve academic accomplishment through a critical period in personal development. For this purpose, the analysis verifying influence of self leadership as an individual trait variable and social support as a socio environmental trait variable on academic achievement of university students and the mediating effect of school adjustment among them was conducted. Total 271 responses collected by implementing a questionnaire survey in "S", a four-year private university located in Seoul, were used for the analysis. The validity of the measurement was verified through confirmatory factor analysis and the relationship among the variables was examined through structural model equation, bootstrap and sobel test. The major finding of this study are as follows. First, this study confirmed the causal relationship of self leadership and social support impacting on academic achievement of university students. This result suggests that an integrated approach taking into account both individual and socio environmental factors is necessary to support academic achievement of university students. Second, it was proved that self leadership and social support indirectly influences academic achievement through school adjustment. This demonstrates that school adjustment is an important predictor of academic achievement as well as plays a major role in mediating among self leadership, social support and academic achievement. In conclusion, the results of this study conveys its significance in suggesting the necessity to provide insititutional support on individual trait and socio environmental factor enabling university students sucessfully to adapt to campus life and achieve academic achievement.

Numerical Approach to Optimize Piercing Punch and Die Shape in Hub Clutch Product (허브클러치 제품의 피어싱 펀치 및 금형 형상 최적화를 위한 수치접근법)

  • Gu, Bon-Joon;Hong, Seok-Moo
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.9
    • /
    • pp.517-524
    • /
    • 2019
  • The overdrive hub clutch is attached to a 6-speed automatic transmission to reduce fuel consumption by using the additional power of the engine. This paper proposes a means to minimize the load and roll-over ratio on the punch during the piercing process for the overdrive hub clutch product. Die clearance, shear angle, and friction coefficient, which can affect the load and roll-over ratio of the punch during processing, were set as the design variables. Sensitivity analysis was also conducted to determine the influence of each design variable on the punch load and roll-over ratio. As a result, shear angle, friction coefficient and die clearance were found to be sensitive to load and roll-over ratio. The punch load and roll-over ratio were set as the objective function and the equation of each design variable and objective function was derives using the Response Surface Method. Finally, the optimal value of the design variables was derived using the Response Surface Method. Application of this model to finite element analysis resulted in 22.14% improvement in the roll-over ratio of the punch load and material.

A Study on the Convergent Factors Related to Self-leadership of Female Freshmen in Health Majors Studying TOEIC (토익을 학습하는 보건계열 신입여대생의 셀프리더쉽과 관련된 융복합적 요인 분석)

  • Hong, Soo-Mi;Bae, Sang-Yun
    • Journal of Digital Convergence
    • /
    • v.17 no.9
    • /
    • pp.259-269
    • /
    • 2019
  • This study analyzed convergent factors related to self-leadership of female freshmen in health majors studying TOEIC. The survey was conducted from April 29, 2019 to May 10, 2019 using unregistered self-administered questionnaire for 201 female freshmen in health majors and they were randomly selected from TOEIC class in college located in J city. The results of hierarchical multiple regression analysis show the following. The self-leadership of respondents turned out to be significantly higher in following groups: a group in which self-competence is higher, a group in which subdivision task self-efficacy and coping self-efficacy is higher, and a group in which subdivision chance of locus control from locus of control is lower. Their explanatory power was 49.7%. The results of the study indicate that the efforts to manage self-competence, self-efficacy, and locus of control are required to improve the self-leadership of female freshmen in health majors studying TOEIC. These results can be used for academic counseling guidance to enhance self-leadership of female freshmen in health majors studying TOEIC. In the future research, it is necessary to establish and analyze a structural equation model that affects self-leadership of male and female college students in health majors studying TOEIC.

A Study on the Relationship between the Management Strategies, Innovation Activities, and Business Performance of a Company (기업의 경영전략 및 혁신활동과 경영성과와의 관계성 연구)

  • Shim, Taeyong;Lee, Daegyu
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.9
    • /
    • pp.156-166
    • /
    • 2019
  • For this study, a survey was conducted with the employees of small and medium-size enterprises (SMEs) located in Seoul and in Gyeonggi province. In the end, a total of 328 valid questionnaires were received and used in the analysis. The data of this study were analyzed using two statistics programs: SPSS Statistics 22.0 and AMOS 22.0. As for the method to verify the hypothesis, we used a structural equation model. The key findings of this study are as follows. First, the results of correlation analysis between management strategy factors, innovation activities, and business performance showed that the factors that were at a higher level of correlation were the technology differentiation strategies, marketing differentiation strategies, and the cost-driven strategy. Second, the strategic management factors that influenced innovation activities were in the following order: marketing differentiation, technology differentiation, and the cost-driven strategy, while the valid factors that affected business performance with significance were only the marketing differentiation strategy and the cost-driven strategy. Third, while the analysis showed that the technology differentiation strategy did not have a direct effect on business performance, it was shown that the relationship between the technology differentiation strategy and business performance was completely mediated by innovation activities.

Impact of CSV and Power Attributes in the Supply Chain on Information Competency (공급사슬 내 CSV와 파워속성이 정보역량에 미치는 영향)

  • Park, Kwang-O
    • Management & Information Systems Review
    • /
    • v.38 no.2
    • /
    • pp.83-103
    • /
    • 2019
  • Supply chain management(SCM) requires efforts to search for methods for mutual growth with partner companies and to maintain continuous cooperative relations in order to gain a competitive edge. Because information competencies play a big role within the supply chain, it is essential to examine the relationship of information sharing and partnership quality that can affect information competency. In order to maintain continuous business relations between partner companies, it is necessary to identify the obstacles with partner companies resulting from the imbalance of power within a supply chain and to take on a strategic approach for effectively managing such obstacles. Therefore, there is a significant need to discuss strategic approach methods to enable the logic of mutual growth through the CSV that is worth learning from the partner company and the attributes of non-mediated power. CSV will be reviewed from various aspects as a new management paradigm in the future. This study aims at suggesting a continuous growth model for companies by solving social problems through the integration of CSV and the concept of non-mediated power to advance the information competencies of SCM. A total of 142 copies of survey forms for SCM Implementation Companies were using the PLS structural equation modeling for an analysis, and the following are the findings. Results of this study showed that both CSV and non-mediated power had significant impact on information sharing and partnership qualities, and the conclusion that it is possible to enhance information competency through information sharing and partnership quality. Based on this, this study proposes the implication that it is necessary to elevate awareness of CSV and non-mediated power as variables for the coexistence of SCM participating companies.

A Study on the Convergent Factors Related to the State Anxiety of Female Administrative Staff in Medical Institution (의료기관 여성 행정직원의 상태불안과 관련된 융복합적 요인)

  • Kim, Seung-Hee;Bae, Sang-Yun
    • Journal of Digital Convergence
    • /
    • v.17 no.8
    • /
    • pp.313-320
    • /
    • 2019
  • This paper was attempted to identify the convergent factors related to the state anxiety of Female Administrative Staff in Medical Institutions(FASMI). For randomly selected 226 FASMI at 27 medical institutions in J region, from July 4, 2018 to July 25, 2018, we conducted an anonymous self-administered questionnaires. As a result of hierarchical multiple regression analysis, the state anxiety of respondents turned out to be significantly higher in following groups: a group in which subjective happiness is lower, a group in which cynicism, sub-areas of job burnout are higher, a group in which psychosocial stress is higher, the explanatory power of them was 57.3%. In conclusion, in order to lower the state anxiety of FASMI, it is necessary to increase subjective happiness, lower cynicism, which is a sub-area of job burnout, and to lower psychosocial stress. These results could be used in hospital job management and mental health education to lower the level of state anxiety in FASMI. Future research needs to develop and interpret a structural equation model that affects the state anxiety of FASMI.

Study on the Suitability of Composite Materials for Enhancement of Automotive Fuel Economy (자동차 연비향상을 위한 복합재료 적용 타당성에 관한 연구)

  • Ju, Yeon Jin;Kwon, Young-Chul;Choi, Heung Soap
    • Composites Research
    • /
    • v.32 no.5
    • /
    • pp.284-289
    • /
    • 2019
  • In the present paper, the dynamic force-moment equilibrium equations, driving power and energy equations are analyzed to formulate the equation for fuel economy(km/liter) equivalent to the driving distance (km) divided by the fuel volume (liter) of the vehicle, a selected model of gasoline powered KIA K3 (1.6v). In addition, the effects of the dynamic parameters such as speed of vehicle (V), vehicle total weight(M), rolling resistance ($C_r$) between tires and road surface, inclined angle of road (${\theta}$), as well as the aerodynamic parameters such as drag coefficient ($C_d$) of vehicle, air density(${\rho}$), cross-sectional area (A) of vehicle, wind speed ($V_w$) have been analyzed. And the possibility of alternative materials such as lightweight metal alloys, fiber reinforced plastic composite materials to replace the conventional steel and casting iron materials and to reduce the weight of the vehicle has been investigated by Ashby's material index method. Through studies, the following results were obtained. The most influencing parameters on the fuel economy at high speed zone (100 km/h) were V, the aerodynamic parameters such as $C_d$, A, ${\rho}$, and $C_r$ and M. While at low speed zone (60 km/h), they are, in magnitude order, dynamic parameters such as V, M, $C_r$ and aerodynamic ones such as $C_d$, A, and ${\rho}$, respectively.

The Relationship between Elementary School Student's Judo Gym Training Program and Life Satisfaction: The Mediation Effect of Social Development (초등학생에 대한 유도체육관 프로그램 특성과 생활만족의 관계: 사회성 발달의 매개효과)

  • Kim, Hwa-Ryong;Lee, Do-Heui
    • Journal of the Korean Applied Science and Technology
    • /
    • v.36 no.1
    • /
    • pp.312-323
    • /
    • 2019
  • This purpose of study was to influence of elementary school student's Judo gym training program on social development and life satisfaction. This study aims at providing fundamental data and information on Judo participants by studying what effects of training program characteristic on social development and life satisfaction. The survey was done through 300 copies and excluding 15 copies ran an analysis on the remaining 285(90%) copies. After question investigating the data which is collected used IBM SPSS statistics 21 and IBM AMOS 21 program, frequency analysis, Exploratory factor analysis and confirmatory factor analysis, convergent validity, discriminant validity, Cronbach's ${\alpha}$, correlation analysis, path analysis through Structural Equation Model(SEM), mediation effect analysis by Sobel test. The result of this study were as follows. First, elementary school student's Judo gym training program showed (+) effects on social development. Second, elementary school student's Judo gym training program had no effects on life satisfaction. Third, social development showed (+) effects on life satisfaction. Forth, social development showed complete mediation effect on elementary school student's Judo gym training program and life satisfaction.

The Effect of E-WOM Quality of Dessert Cafe on Perceived Value and Visit Intention (디저트 카페의 온라인 구전 품질이 지각된 가치와 방문의도에 미치는 영향)

  • Kim, Sang Bum;Kim, Hong-Keun
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.14 no.2
    • /
    • pp.199-209
    • /
    • 2019
  • With the rapid development of mobile communication tools, customers are using SNS as a major information tool. SNS can provide information to a small number of customers as well as people around them, with information about a product or service that a small number of customers know through experience. With these characteristics, dessert cafes are being used as a major marketing tool for online websites and mobile phones using SNS. Therefore, in this study, theoretical considerations about e-WOM quality, perceived value, and visit intention were performed. The effect of e-WOM quality of dessert cafe on perceived value was analyzed and the effect of perceived value on visit intention was analyzed. Based on these results, I would like to suggest theoretical implications and practical implications for online marketing of dessert cafes. This study was conducted to survey the customers who have visited dessert cafe through oral communication within the last 6 months. The survey was conducted from September 4, 2018 to September 18, 2018, and was used for the analysis of 317 additional items. The research hypotheses between the e-WOM quality of the dessert cafe and the utilitarian value, hedonic value, and visiting intention were used the structural equation model(SEM). First, neutrality and interactivity have a significant effect on utilitarian value, but consensus and vividness have not significant effect. Second, It was found that the consensus, vividness, and neutrality had a significant effect on the hedonic value but interactivity was not found to have a significant effect. Third, hedonic value has a significant effect on visit intention, but utilitarian value has not significant effect. As a result, online e-WOM quality management is important.