• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.102-105
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• 2002

A new finite difference model is developed for solute transport in a fractured medium that can consider advection, adsorption, first-order decay, and scale-dependent dispersivity of individual fractures. In the model, the dispersivity of individual fractures is employed as a variable increasing with travel distance from a source. The model is verified using an analytical solution for a single fracture. A solution from the new model is independent of the outlet boundary condition of fractures, and has little numerical dispersion error.

• KIEAE Journal
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• v.4 no.3
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• pp.27-35
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• 2004

The conventional way to acquire sufficient amount of daylight in interiors is to provide large openings with clear glass. The use of clear glass on the whole facade, however, might cause a sort of visual problem because of the harness of direct sun and brighter sky surface than expected. They should be filtered in opticalway or bounced in the architectural. One of the common solutions for the problem might be the use of photometric glasses with various transmittances for the glass walls. This paper deals with performance data related to the impact of various transmittal glazing materials for window systems in terms of daylighting. A series of scale model measurements was carried out with the fundamental configuration of a commonly used all-glass facades. Additionally some experimental performance index was issued for the better expression of the need of natural lighting.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.724-732
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• 2016

In this paper, a sampled-data observer-based decentralized fuzzy control technique is proposed for a class of nonlinear large-scale systems, which can be represented to a Takagi-Sugeno fuzzy system. The premise variable is assumed to be measurable for the design of the observer-based fuzzy controller, and the closed-loop system is obtained. Based on an exact discretized model of the closed-loop system, the stability condition is derived for the closed-loop system. Also, the stability condition is converted into the linear matrix inequality (LMI) format. Finally, an example is provided to verify the effectiveness of the proposed techniques.

• Steel and Composite Structures
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• v.26 no.1
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• pp.89-102
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• 2018

This work investigates a novel plate formulation and a modified couple stress theory that introduces a variable length scale parameter is presented to discuss the static and dynamic of functionally graded (FG) micro-plates. A new type of third-order shear deformation theory of Reddy that use only 4 unknowns by including undetermined integral variables is proposed in this study. The equations of motion are derived from Hamilton's principle. Analytical solutions are obtained for a simply supported micro-plate. Numerical examples are presented to examine the effect of the length scale parameter on the responses of micro-plates. The obtained results are compared with the previously published results to demonstrate the correctness of the present formulation.

• Journal of the Korea Furniture Society
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• v.12 no.2
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• pp.73-80
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• 2001

The purpose of human factor study is to help the people in good conditions, and to increase the efficiency of physical productivity and mental creativity Also for the furniture design field, the applications of human scale dimensions are considered as the very important aspects. For the design of the office systems furniture, designer must consider the onveniences of variable users as much as possible. To design the office systems for the various work environment, it is necessary to analyze the human scale dimensions according to the furniture items and the user behaviors. In these days, many countries are interested about the workplace ergonomic regulations to reduce a class of injuries called ‘Musculoskeletal Disorders(MSDs)’ by controlling risk factors. In this study, I intend to research and to analyze the features of human scale dimensions and the user behaviors of office environment, and propose some office furniture design tips.

• Korean Institute of Interior Design Journal
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• v.15 no.6 s.59
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• pp.255-263
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• 2006

This research analyze the demand of the residents against the public housing remodeling of national housing scale $(85m^2)$, focusing on residents and their tendencies within their dwelling spaces. The analysis determines the most appropriate patterns and spatial connections within the floor plan. The result includes that there are two types of the classification into an urban oriented propensity (45%), 'The center of city, the apartment and the convenience' etc, and a rural oriented propensity (55%), 'The pastoral, the house and the circumstance' etc, based on their lifestyle values. Also there are three interior propensity classifications, those tending to warm and sensitive variable space (42%), western and gorgeous dynamic space (34%) and oriental and popular static space (24%). The research illustrated the residents' desired space planning options, based on the analysis of the residents' preference patterns which is various.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.8
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• pp.651-655
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• 2005

In this paper, we consider the problem of designing decentralized sliding mode control laws far a class of large scale systems with mismatched uncertainties. We derive a sufficient condition far the existence of a linear switching surface in terms of a linear matrix inequalities(LMIs), and we parameterize the linear switching surfaces in terms of the solution matrices to the given LMI existence conditions. We also give an algorithm for designing decentralized switching feedback control laws. Finally, we give a design example in order to show the effectiveness of our method.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.758-771
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• 2021

This paper presents a novel control scheme for the three-dimensional (3D) path following of underactuated Autonomous Underwater Vehicle (AUVs) subject to unknown internal and external disturbances, in term of the time scale decomposition method. As illustration, two-time scale motions are first artificially forced into the closed-loop control system, by appropriately selecting the control gain of the integrator. Using the singular perturbation theory, the integrator is considered as a fast dynamical control law that designed to shape the space configuration of fast variable. And then the stabilizing controller is designed in the reduced model independently, based on the time scale decomposition method, leading to a relatively simple control law. The stability of the resultant closed-loop system is demonstrated by constructing a composite Lyapunov function. Finally, simulation results are provided to prove the efficacy of the proposed controller for path following of underactuated AUVs under internal and external disturbances.

• Steel and Composite Structures
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• v.46 no.4
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• pp.513-523
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• 2023

Buckling and post-buckling behaviors of geometrically perfect double-curvature shells made from smart composites have been investigated. The shell has been supposed to be exposed to transverse mechanical loading and magneto-electro-elastic (MEE) coupling. The composite shell has been made of two constituents which are piezoelectric and magnetic ingredients. Thus, the elastic properties might be variable based upon the percentages of the constituents. Incorporating small scale impacts in regard to nonlocal theory leads to the establishment of the governing equations for the double-curvature nanoshell. Such nanoshell stability will be shown to be affected by composite ingredients. More focus has been paid to the effects of small scale factor, electric voltage and magnetic intensity on stability curves of the nanoshell.

• International Journal of Advanced Culture Technology
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• v.11 no.4
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• pp.163-168
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• 2023

The purpose of the study was to examine the mediating effect of early childhood teachers' professional development in the relationship between intrapersonal intelligence and teacher-child interactions. We conducted a cross-sectional study with 324 early childhood teachers working at kindergartens and child-care centers in South Korea. The empirical data using survey questionnaires were collected by administering the Adult Introspective Intelligence Scale, the Professional Development Scale for Early Childhood Teachers, and the Teacher-child Interactions Scale. SPSS and Hayes' PROCESS macro weres utilized. The results showed the statistically positive correlations between the major variable and the mediating effect of early childhood teachers' professional development in the relationship between intrapersonal intelligence and teacher-child interactions.