• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.506-517
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• 2000

One dimensional performance model has been used for the design of torque converter. The model is based on the concept of constant mean flow path and constant flow angle. These constant-assumed para meters make the design procedure to be simple. In practice, some parameters are usually replaced with geometric raw data and, the constant experiential correction factors have been used to minimize the design error. These factors have no definite physical meaning and so they cannot be applied confidently to the other design condition. In this study, the detail dynamic model of torque converter is presented to establish the theoretical background of correction factors. To verify the validity of theoretical model, steady state performance test was carried out on the several input speed. The oil temperature effect on the performance is analysed and adjusted. The constant equivalent flow angles are determined at a part of performance region by comparing the theoretical model and the test data. The sensitivity of correction factors to the input speeds are studied and the change of torus flow is presented.

• Korean Journal of Adult Nursing
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• v.18 no.3
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• pp.488-499
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• 2006

Purpose: Behavioral symptoms in dementia (BSD) are one of the most disturbing behaviors to caregivers and a major reason for nursing home placement. Behavioral symptoms are often treated with psychotropic drugs (PD), however, the effect of such drugs for the frail elderly dementia patient is not certain because of their critical adverse effects. Theoretical model applicable to nursing practice for BSD in nursing homes, which is essential in guiding and evaluating such interventions, is absent. This article presents the process of developing a theoretical model of BSD in nursing homes. Method: Using Walker and Avants' theory synthesis method, three behavior models and two system models were incorporated into the proposed model to provide the theoretical and analytical explanation of the relationships between PD usage, its determinants, and BSD. Results: Resident variables and nursing home variables related to the two focal concepts (i.e., PD usage and BSD) were identified. Resident variables include demographical characteristics such as age and gender, and dementia-compromised functions such as cognitive and functional impairment. Nursing home variables include facility characteristics such as ownership type and size, and physical and psychosocial environment. Conclusion: The proposed model suggests that fulfillment of resident unmet needs through improvement of physical and psychosocial environment may produce better health outcomes of nursing home residents with BSD. Assessment and intervening environmental triggers of such behaviors are also suggested to be prior to the PD usage.

• Journal of The Korean Association For Science Education
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• v.25 no.6
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• pp.698-709
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• 2005

When modeling students' conceptual understanding, there are several different frameworks, among which are the alternative conception framework and the mental model framework, which converge to suggest a form of knowledge representation. However, little research has explained how they are different from each other and from memory. The purpose of this study was to develop a new mental model theory that integrates the different terminologies and their background theories, which refer to students' ideas not only in science education, but also in other research areas. For this purpose, at first, we compared different terminologies including alternative conception, p-prim, and mental models, and the underlying theories used for representing students' ideas in learning science. Through such comparison, we tried to find the relationship among them. We reviewed related literature and synthesized the results from both cognitive science (related research areas) and science education approaches, especially, Vosniadou's mental model theory. Based on reviewing previous studies, we have developed a preliminary mental model theory 'an integrated theoretical structure of mental models'. We applied the new mental model theory to interpret data on students' ideas about circular motion from our previous research. We expect our new mental model theory will help us understand how students form their own ideas in science from an integrated perspective.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.4
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• pp.637-650
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• 1995

The purpose of the study was to develop a model to explain how a fashion style is determined within a society and how the style diffuses. The research was carried out in two stages, theoretical study followed by empirical study. In the theoretical study, explanatory model about decision of fashion style and diffusion was developed and then fashion diffusion theories and fashion phenomenon of postholder society were explained by the model developed. The theoretical framework of the explanatory model was constructed in that fashion changes by ambivalence of pursuit values within an individual as well as within a society. The empirical study was carried out to validate the model by looking into fashion phenomenon in the postmodern society A questionnaire was developed including style image, pursuit value, preference style and administered to 19 to 30 year-old women living in Seoul area. Frequency distribution, discriminant analysis, one-way ANOVA. were used for the statistical analysis. As pursuit values differed in each style preference stoup, and pursuit value coincided with image of preference style it was confirmed that clothing selection behavior was determined by pursuit value. In a postmodern society where variety of values are pursued, appearance of various products and preference of all styles altogether considered, it could assume that subcultural collective selection phenomenon appeared.

• Steel and Composite Structures
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• v.38 no.6
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• pp.717-737
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• 2021

A theoretical energy-based model to capture the mechanical response of thick woven composite laminates, which are used in such applications as maritime or aerospace, to high-velocity impact was developed. The dependences of the impact phenomenon on material and geometrical parameters were analysed making use of the Vaschy-Buckingham Theorem to provide a non-dimensional framework. The model was divided in three different stages splitting the physical interpretation of the perforation process: a first where different dissipative mechanisms such as compression or shear plugging were considered, a second where a transference of linear momentum was assumed and a third where only friction took place. The model was validated against experimental data along with a 3D finite element model. The numerical simulations were used to validate some of the new hypotheses assumed in the theoretical model to provide a more accurate explanation of the phenomena taking place during a high-velocity impact.

• Journal of Information Technology Applications and Management
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• v.21 no.4
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• pp.225-245
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• 2014

ICT based convergence application is one of the most prevalent industrial issue these days. Despite of criticalness and potential economic opportunities of the ICT based convergence, theoretical research to analyze the feasibility and estimate the economic impact of the application is rather limited. This paper is intended to fill this research gap. In this respect, we develop theoretical framework to quantitatively estimate the differential benefits of convergent applications, which necessarily include underling ICT technology's contribution attributes extractions, and resulting value increments engendered from user's process effectiveness when ICT based service application is adopted. The research model to assess the differential value of the ICT based service application is developed, grounded on theoretical framework of TPC (Technology-to-performance chain) and contingency fit theories. Scenario based survey method is adopted, and SmartPLS 2.0. is used for statistical analysis of the structural equation model using 312 questionnaire. Valid statistical results are presented to provide useful insight.

• Korea journal of population studies
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• v.12 no.1
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• pp.30-42
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• 1989

This study develops a model of migration decision-making process, with identifying macrolevel and microlevel factors affecting the process. The model includes some sequential stages : to be dissatisfied with current residential area, intend to move, collect information about alternative destinations, select destination, decide to move, and make actual migration. The macrolevel factors included in the model are environmental, socioeconomic, cultural, and demographic characteristics of the current residence and alternative destinations. The microlevel factors are psychological, socioeconomic, and demographic characteristics of the individual. The effects of the macrolevel and microlevel factors on each stage of migration decision-making process are identified from the previous studies on migration. This study has both theoretical and practical implications. The theoretical contribution will be in the area of integrating the ecological and the individual level perspectives of migration by identifying the macrolevel and microlevel effects on migration decision-making process. This study also has implications for theoretical frameworks guiding empirical analysis of migration behavior of the individuals, and for policies aimed at redistributing population.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.714-719
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• 2000

The analysis of structures may be classified into three categories: theoretical, numerical, and experimental approaches. The numerical and experimental methods are very useful when the structures to be analyzed have complicated shapes or geometry because theoretical methods are restricted to simple and special cases. However, the theoretical methods are very important analysis in the viewpoint that they can give basic insight for the structural behavior. Among them the modal model method is widely used because of the powerful propertiy of eigenfunctions(mode shapes), or orthogonality. In this paper, the modal model method was reviewed and studied for various models for structures: string, beam, membrane, and plate. Governing equations and solution methods were compared and a structural-acoustic coupling system was used for an application.

• Geomechanics and Engineering
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• v.19 no.2
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• pp.141-151
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• 2019

A novel theoretical solution is presented for created (zero initial radius) cavity expansion problem based on CamClay model and considers the effect of initial anisotropic in-situ stress and drained conditions. Here the strain of this theoretical solution is small deformation in elastic region and large deformation in plastic region. The works for cylindrical and spherical cavities expanding in drained condition from zero initial radius are investigated. Most of the conventional solutions were based on the isotropic and undrained condition, however, the initial stress state of natural soil mass is anisotropy by soil deposition history, and drained cavity expansion calculation is closer to actual engineering in permeable soil mass. Finally, the parametric study is presented in order to the engineering significance of this work.

• Journal of the Optical Society of Korea
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• v.17 no.1
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• pp.22-26
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• 2013

The author analyzes the luminous efficiency of the phosphor-conversion white light-emitting diode (LED) that consists of a blue LED chip and a yellow phosphor. A theoretical model is derived to find the relation between luminous efficiency (LE) of a white LED, wall-plug efficiency (WPE) of a blue LED chip, and the phosphor absorption ratio of blue light. The presented model enables to obtain the theoretical limit of LE and the lower bound of WPE. When the efficiency model is applied to the measured results of a phosphor-conversion white LED, the limit theoretical value of LE is obtained to be 261 lm/W. In addition, for LE of 88 lm/W at 350 mA, the lower bound of WPE in the blue LED chip is found to be ~34%. The phosphor absorption ratio of blue light was found to have an important role in optimizing the luminous efficiency and colorimetric properties of phosphor-conversion white LEDs.