• Title/Summary/Keyword: structure equation modeling

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Structural Equation Modeling on Case Management Outcomes and Factors Influencing Outcomes in the Community-dwelling Vulnerable Elders (취약계층 재가노인의 사례관리 성과와 영향요인에 관한 구조모형 구축)

  • Moon, Hyunjung;Lee, In-Sook
    • Journal of Korean Academy of Nursing
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    • v.43 no.6
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    • pp.791-800
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    • 2013
  • Purpose: This study was done to test a structural equation modeling of case management outcomes in order to identify parameters affecting case management outcomes for the community-dwelling vulnerable elders. Methods: Data were collected from 309 nurses (case managers) and community-dwelling vulnerable elders (clients) from public health centers. For data analysis, descriptive statistics, Pearson correlation analysis, factor analysis, and covariance structure analysis were performed using SPSS Version 18.0 for Windows and Amos 16.0. Results: The hypothetical model had an acceptable fit: GFI=.97, CFI=.95, RMSEA=.02, SRMR=.05. The factor "case managers' singularity" had the greatest impact on case management outcomes in this model. In addition, the factor "case management practice" influenced case management outcomes; however, client characteristics did not. Case managers' singularity affected case management outcomes directly and indirectly, with case management practice mediating the latter effect. Conclusion: These results suggest that the causal relationship between case management outcomes and factors influencing these outcomes should be clarified through longitudinal research including a variety of client characteristics. In addition, in future studies, analysis of the effects of programs to improve manpower quality and examine the relationships among case management outcomes should be done.

An Analysis on the Satisfaction Level of Specialty Shops for Environment-Friendly Agricultural Products (친환경농산물 전문매장의 서비스품질만족도 분석)

  • Seo, Dong-Woo;Heo, Seung-Wook
    • Korean Journal of Organic Agriculture
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    • v.18 no.3
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    • pp.315-329
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    • 2010
  • This study focused on analysis of the satisfaction level of specialty shops for environment-friendly agricultural products (EFAP). To analyze the satisfaction level of EF AP, a series of household surveys were conducted. Questionnaire was prepared on the basis of the SERVQUAL model and the structural equation modeling was made on the basis of the contents surveyed. The main results of this study are summarized as follows. Firstly, tangibles structured with store clearance, neat uniform, information and others is the factor of service quality satisfaction. Secondly, reliability structured with service practice, problem solving, and service in accurate time is the factor of service quality satisfaction. Thirdly, assurance structured with the reliability of employees, sufficient knowledge of employees, courteous and good manner is the factor of service quality satisfaction. Fourthly, responsiveness structured with prompt service, voluntary help, customer response service and the like is the factor of service quality satisfaction. Fifthly, the sympathy structured in interest for each customer, provision of service in time convenient to use, encountering the customers with genuine feeling are the factors of service quality satisfaction. And sixthly, the service satisfaction factors would influence on the consumer behavior factors.

On the receding contact between a two-layer inhomogeneous laminate and a half-plane

  • Liu, Zhixin;Yan, Jie;Mi, Changwen
    • Structural Engineering and Mechanics
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    • v.66 no.3
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    • pp.329-341
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    • 2018
  • This paper considers the smooth receding contact problem between a homogeneous half-plane and a composite laminate composed of an inhomogeneously coated elastic layer. The inhomogeneity of the elastic modulus of the coating is approximated by an exponential function along the thickness dimension. The three-component structure is pressed together by either a concentrated force or uniform pressures applied at the top surface of the composite laminate. Both semianalytical and finite element analysis are performed to solve for the extent of contact and the contact pressure. In the semianalytical formulation, Fourier integral transformation of governing equations and boundary conditions leads to a singular integral equation of Cauchy-type, which can be numerically integrated by Gauss-Chebyshev quadrature to a desired degree of accuracy. In the finite element modeling, the functionally graded coating is divided into homogeneous sublayers and the shear modulus of each sublayer is assigned at its lower boundary following the predefined exponential variation. In postprocessing, the stresses of any node belonging to sublayer interfaces are averaged over its surrounding elements. The results obtained from the semianalytical analysis are successfully validated against literature results and those of the finite element modeling. Extensive parametric studies suggest the practicability of optimizing the receding contact peak stress and the extent of contact in multilayered structures by the introduction of functionally graded coatings.

Position Control for a Flexible Manipulator Using Sliding Modes (슬라이딩 모드를 이용한 유연한 매니퓰레이터의 위치제어)

  • 김정구;박창용
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.321-321
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    • 2000
  • This paper presents a sliding mode controller based on variable structure for the tip position control of a single-link flexible manipulator. Dynamic equations of a single-link flexible manipulator are derived from the Euler-Lagrange equation using a Lagrangian assumed modes method based on Bernoulli-Euler Beam theory. Simulation results are presented to show the validity of the system modeling, controller design.

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Mapping of the lost riprap in shallow marine sediments using SBP (SBP를 이용한 해저 천부에 유실된 사석의 조사)

  • Shin, Sung-Ryul;Kim, Chan-Su;Yeo, Eun-Min;Kim, Young-Jun;Ha, Hee-Sang
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.11a
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    • pp.220-221
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    • 2005
  • Sub-bottom profiler(SBP) has been used extensively for the mapping of basement in the foundation design of offshore structure, for pre- and post-dredging operations within harbors and channels, for selection of pipeline routes, sitting of drilling platforms, and in the exploration for an aggregates such as sands and gravels. During the construction of Siwha embankment for irrigation water and the expansion of arable land, the breaking of an embankment unfortunately occurred so that a lot of riprap was swept away and widely dispersed by the tide and strong current. The feasibility study for the construction of the tidal-powered electric plant in Siwha embankment was performed quite recently. Therefore we made use of SBP survey to investigate the distribution of the lost riprap. We could successfully map out the distribution of the lost riprap from the reflection amplitude characteristics of the sediments in SBP data set. We demonstrated the variation of reflection amplitude versus the sediments with and/or without riprap by means of the numerical modeling of acoustic wave equation using finite difference method. Also we examined an amplitude anomaly of the ripraped area through the physical modeling using ultrasonic.

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A Study on the Effect of Pattern Density and it`s Modeling for ILD CMP (패턴 웨이퍼의 화학기계적 연마시 패턴 밀도의 영향과 모델링에 관한 연구)

  • Hong, Gi-Sik;Kim, Hyung-Jae;Jeong, Hae-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.1
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    • pp.196-203
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    • 2002
  • Generally, non-uniformity and removal rate are important factors on measurements of both wafer and die scale. In this study, we verify the effects of the pressure and relative velocity on the results of the chemical mechanical polishing and the effect of pattern density on inter layer dielectric chemical mechanical polishing of patterned wafer. We suggest an appropriate modeling equation, transformed from Preston\`s equations which was used in glass polishing, and simulate the removal rate of patterned wafer in chemical mechanical polishing. Results indicate that the pressure and relative velocity are dominant factors for the chemical mechanical polishing and pattern density effects on removal rate of pattern wafers in die scale. The modeling is well agreed to middle and low density structures of the die. Actually, the die used in Fab. was designed to have an appropriate density, therefore the modeling will be suitable for estimating the results of ILD CMP.

Evolutionary computational approaches for data-driven modeling of multi-dimensional memory-dependent systems

  • Bolourchi, Ali;Masri, Sami F.
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.897-911
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    • 2015
  • This study presents a novel approach based on advancements in Evolutionary Computation for data-driven modeling of complex multi-dimensional memory-dependent systems. The investigated example is a benchmark coupled three-dimensional system that incorporates 6 Bouc-Wen elements, and is subjected to external excitations at three points. The proposed technique of this research adapts Genetic Programming for discovering the optimum structure of the differential equation of an auxiliary variable associated with every specific degree-of-freedom of this system that integrates the imposed effect of vibrations at all other degrees-of-freedom. After the termination of the first phase of the optimization process, a system of differential equations is formed that represent the multi-dimensional hysteretic system. Then, the parameters of this system of differential equations are optimized in the second phase using Genetic Algorithms to yield accurate response estimates globally, because the separately obtained differential equations are coupled essentially, and their true performance can be assessed only when the entire system of coupled differential equations is solved. The resultant model after the second phase of optimization is a low-order low-complexity surrogate computational model that represents the investigated three-dimensional memory-dependent system. Hence, this research presents a promising data-driven modeling technique for obtaining optimized representative models for multi-dimensional hysteretic systems that yield reasonably accurate results, and can be generalized to many problems, in various fields, ranging from engineering to economics as well as biology.

Estimation of Post Evaluation Index of Natural Disaster Prevention Projects using Structure Equation Modeling (구조방정식모델을 이용한 자연재해예방사업의 사후 평가 지수 산정)

  • Heo, Bo Young;Song, Jai Woo;Yoon, Sei Eui;Lee, Seung Oh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.6
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    • pp.1807-1814
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    • 2014
  • Natural disaster has been hard to prevent the occurrence of itself, thus in order to reduce the economic damages and loss casualties, it is important to be prepared in cases that the disasters should occur in advance. Interest of the related project to prevent various natural disasters has been grown along with an investment in Korea. Along with this movement, when investments related to natural disaster prevention projects were built on, the post evaluation that can verify the ripple effects of those investments on the community should be emerging as an essential task. For evaluating the effects of public investment projects such as natural disaster prevention projects in this study, the related researches would continue through qualitative analyses, for example, cost-benefit analysis. Even the qualitative analysis alone cannot fully explain the effects of those projects, the diverse methods of analyzing and evaluating those effects might not have been presented in those fields. For the post evaluation of natural disaster prevention projects through the qualitative analysis, this study derived subjects that had effects on the post evaluation of natural disaster prevention projects. Also, employing the structural equation modeling (SEM), the causation between post evaluation subjects and the effects of projects were quantitatively analyzed, and the weighting factors of evaluation items were calculated respectively. Based on these results, post evaluation index formula was proposed for the natural disaster prevention projects in Korea.

Modeling for Soot Formation Coupled with Detailed Chemistry in Laminar Pressurized Non-premixed Flames (층류 고압 비예혼합 화염에서 상세화학반응과 결합된 매연입자 생성 모델링)

  • Kim, Taehoon;Jeon, Sangtae;Kim, Yongmo
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.139-140
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    • 2012
  • In laminar non-premixed flame situation, the flamelet model is not suitable for simulating slow processor like soot and radiation. Thus in this study, we overcome this limitation by using the transient flamelet model. Also, for soot formation on laminar non-premixed flame, transient flamelet coupled with two-equation soot model has been adopted due to its inherent advantages in terms of accuracy and availability. Based on numerical results, the detailed discussion has been made for the precise structure and soot formation processes in the pressurized methane air flames.

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Unsteady Flamelet Modeling for Flame Structure and Soot Formation of Lanimar Non-premixed CH4/Air Flame (비정상 화염편 모델을 이용한 대기압 층류 비예혼합 CH4/Air 화염장의 매연입자 생성 특성 및 화염구조 해석)

  • Kim, Taehoon;Jeon, Sangtae;Kim, Yongmo
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.137-138
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    • 2012
  • The two-equation soot model based on the transient laminar flamelet model is implemented for soot formation of laminar non-premixed $CH_4/Air$ flame with detailed chemical reaction mechanism and complex thermodynamic properties. The soot model represents nucleation, growth and oxidation with gas-phase chemistry. This represented unsteady flamelet soot model has been tested and compared using well verified reference calculation result obtained solving the Full Transport Equations method.

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