• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.4
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• pp.213-219
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• 2000

In this paper, a controller design method is proposed for haptic interface considering transparency and robust stability. For this, a performance index for the transparency as performance measure is defined in the points of impedance matching and the optimal solution which is minimizing the performance index is obtained by solving H2 optimal problem. In haptic interface, the modeling uncertainties can be restricted to that of haptic device. To implement the robust stabilizing haptic controller to the uncertainties of haptic device, a robust stable condition using H$\infty$ norm from small gain theorem is proposed. To verify the effectiveness of the proposed haptic controller design scheme, numerical examples and experimental results are illustrated for virtual wall consisting of stiffness and damping factor.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.3
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• pp.102-110
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• 2000

In this paper, Wiener-Hopf design of the two-degree-of-freedom(2DOF) controller configuration is treated for the standard plant model. It is shown that the 2DOF structure makes it possible to treat the design of feedback properties and reference tracking problem separately. Wiener-Hopf factorization technique is used to obtain the optimal controller which minimizes a given quadratic cost index. The class of all stabilizing controllers that yield finite cost index is also characterized. An illustrative example is given for the step reference tracking problem which can not be treated by the conventional H2 controller formula.

• Structural Engineering and Mechanics
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• v.45 no.2
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• pp.211-232
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• 2013

In this study a multi-objective optimization problem is solved. The objectives used here include simultaneous minimum construction cost in term of sections weight, minimum structural damage using a damage index, and minimum non-structural damage in term of inter-story drift under the applied ground motions. A high-speed and low-error neural network is trained and employed in the process of optimization to estimate the results of non-linear time history analysis. This approach can be utilized for all steel or concrete frame structures. In this study, the optimal design of a planar eccentric braced steel frame is performed with great detail, using the presented multi-objective algorithm with a discrete population and then a moment resisting frame is solved as a supplementary example.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04a
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• pp.525-530
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• 1995

The main objective of this study is to develop a gripper mechanism that can be employed for assembly and removal tasks of a nozzle-dam of steam gererator which is one of the nuclear reactor maintenance process. Brief description of the open-close type gripper mechanism, its postion analysis, and its kinematic amalysis are given. The optimal design of the gripper mechanism with slipping on its two gripping surfaces is considered. As an optimaldesign index, the ratio of the actuator force of prismatic cylinder to gripping load is proposed. Then, based on this index the optimal design synthesis is careied out to identify values of optimal design parameters for the gripper mechanism.

• Korean Journal of Construction Engineering and Management
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• v.1 no.1 s.1
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• pp.72-79
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• 2000

Design quality in constructed project is a primary consideration to achieve overall project objectives. It is not easy to evaluate the design quality because various factors are involved in the design process. This paper presents a new approach to improve the evaluation process of design quality In the construction project The evaluation model is developed to satisfy the requirement for implementing the ISO 9000 Quality Assurance Standards in the design process. It is assumed that design changes are resulted from the poor management of design quality. The model relates design changes to design quality management items. It assigns weight ratio to each design quality item to evaluate quantitatively Design Quality Index (DQI) is calculated to assess design quality based on the Objectives Matrix. A case study is performed to illustrate the practical implementation of the design quality evaluation.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.495-501
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• 2011

The load combinations in current KCI Design Code are determined with reference to those in ACI 318-05, which adopts the LRFD (load and resistance factor design) format. The load and resistance factors in LRFD format should be determined to meet the required levels of reliability index or probability of failure for various predetermined failure modes, which are also based on the statistical data reflecting locality and contemporary situation. However, the current KCI Design Code has been written utilizing foreign data, because of insufficiency in accrued data in Korea. This study considered the current safety levels of KCI Code based on published domestic data to evaluate appropriateness of the current KCI regulations. Based on the calibrated reliability index of the existing Code, the new resistance factors are suggested. The results presented in this paper can be considered as a basic research for establishment of unique design format for future Korean Codes.

• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.131-141
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• 2021

The present study is following a series of research investigations on design resources coming from collected data referring to users' awareness and preferences. The aim of this research is to test the Healthcare Environmental Color Index as a basis for practitioners in the field of healthcare design. An array of color samples selected from previous research, have been presented to the respondents via an online survey, in order to identify the preferences of the two groups on the relation between environmental color and health. As a result of the first experiment and through the comparison of processed data, the maximum percentage of respondents from each group is validating the relation between environmental color and health. For the second experiment we intend to highlight the patterns of color preferences for each group, and thus to test the color samples healing function. The compared data also showed a higher awareness of Koreans than Romanians on the potential of color applied to healing environment. Last but not least in the third experiment we show the top five color samples preferred by each group. It is significant that the comparison of the results validated once more some of our previous findings related to the healthcare environment, such as: the general preference for the green hue (associated to fatigue relax according to color psychology) and the blue hue (sedation release effect) but also the yellow hue - associated to bright energy. Three out of the top five preferred color samples have been identical to both groups while the other two samples have shown characteristic variations. These results show that similarities are strong and can be used in a glocal design strategy as an accessible tool for any practitioner. Based on the Healthcare Environmental Color Index and users' preferences analysis, a new design culture for healthcare can be established and developed.

• Journal of Korean Society of Steel Construction
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• v.15 no.4 s.65
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• pp.389-401
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• 2003

The purpose of this study is to develop an algorithm, which can be designed the optimal sections of the composite framed structures constituted with the beams and the columns consisted of H type of steel section and concrete considering the reliability index. The optimized problem or the composite framed structures is formulated with the objective function and the constraints taking the section sizes as the design variables. The objective functions are constituted by the total costs of constructions. Also, the constraints are derived by considering the reliability index of section stress and allowable stress. The algorithm optimized the section of the composite framed structures utilizes the SUMT method using the modified Newton-Raphson direction method. The optimizing algorithm developed in this study is applied to the numerical examples with respecting a one-bay, one-story composite framed structure and a one-bay five-story one for the practical utilization of design on the composite framed structures using the reliability indices$({\beta})$ three and zero. In addition, their numerical results are compared and analyzed to examine the possibility of optimization the applicability, and the convergence this algorithm.

• KIEAE Journal
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• v.16 no.6
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• pp.51-56
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• 2016

Purpose: As declines in the quality of residential environments occur, such as urban heat island effect, tropical night phenomenon, and violations of right to light and privacy due to urban densification and high rise building, these problems are emerging as social issues. In order to improve these issues, design factors which consider environmental aspects must be selected when planning apartment complexes, and ways to reflect them in the planning phase must be explored. Method: In this study, the analytical hierarchy process(AHP) was used to deduce design factors that considered environmental elements during the planning of apartment complexes. Furthermore, the priority and weight for each evaluation index were assessed. The objective was to propose a guideline for planning apartment complexes by finding the best solution for each evaluation index using complex weight values. Result: Floor area ratio was selected as the most important evaluation criterion in the environmentally conscious evaluation index for apartment complex planning. The shape and placement of skylights were selected as the most important evaluation criteria in the sunshine environment for a pleasant residential environment. Ground surface cover design was selected as the most important criterion in the outdoor thermal environment index for improving the microclimate within cities and apartment complexes. Thus, the results of this study can serve as an investigation guideline that concerns policy and regulations, and as reference data that can be used in planning apartment complexes.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.2
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• pp.95-107
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• 2002

A reliability analysis on sliding of monolithic vertical caisson of composite breakwaters is extensively carried out in order to make the basis for the applicability of reliability-based design method. The required width of caisson of composite breakwaters is determined by the deterministic design method including the effect of impulsive breaking waves as a function of water depth, also studied interactively with the results of reliability analyses. It is found that the safety factor applied in current design may be a little over-weighted magnitude for the sliding of caisson. The reliability index/failure probability is also seen to slowly decrease as the water depth increases for a given wave condition and a safety factor. In addition, optimal safety factor can roughly be evaluated by using the concept of target reliability index for several incident waves. The variations of optimal safety factor may be resulted from the different wave conditions. Finally, it may be concluded from the sensitivity studies that the reliability index may be more depended on the incident wave angles and the wave periodsrather than on the bottom slopes and the thickness of rubble mound.