• Structural Engineering and Mechanics
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• v.54 no.6
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• pp.1097-1109
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• 2015

A novel optimization approach for reinforced concrete (RC) biaxially loaded columns is proposed. Since there are several design constraints and influences, a new computation methodology using iterative analyses for several stages is proposed. In the proposed methodology random iterations are combined with music inspired metaheuristic algorithm called harmony search by modifying the classical rules of the employed algorithm for the problem. Differently from previous approaches, a detailed and practical optimum reinforcement design is done in addition to optimization of dimensions. The main objective of the optimization is the total material cost and the optimization is important for RC members since steel and concrete are very different materials in cost and properties. The methodology was applied for 12 cases of flexural moment combinations. Also, the optimum results are found by using 3 different axial forces for all cases. According to the results, the proposed method is effective to find a detailed optimum result with different number of bars and various sizes which can be only found by 2000 trial of an engineer. Thus, the cost economy is provided by using optimum bars with different sizes.

• Korean Institute of Interior Design Journal
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• no.37
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• pp.3-11
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• 2003

The study Is Intended to investigate and analyze the system and practice that have been applied to Interior Architecture, comparing with a number of similar foreign cases, in an attempt to seek the way toward its development as well as to come up with the solution for enhancing the competitiveness, thereby making a recommendation on how to create the desirable work environment of Interior Architecture down the road. The conclusion and recommendation we have made is highlighted as follow. Among the practical or procedural challenges in the process of improving work environment of Interior Architecture, development of current national technical qualification system in a way of further detailing the categories of Ki-sul-sa(highest engineer grade) or Ki-neung-jang(highest technician grade) as part of measures aimed at gradual approaching for improvement of design fees and rates or supervision fees will be very crucial, that calls for close coordination with the Ministry of Labor and Human Resources Development Service of Korea. In a bid to upgrade the Interior Architecture to become the part of knowledge-based industry, amendment to Korean Standard Industrial Classification along with Standard Classification of Occupations and Academic Classification will be essential, and moreover with the attitude of reflection and self-improvement, the endeavors to be able to deal with the revision of existing laws and regulations in a consistent way and manner, by forming a joint committee among the three Interior Architecture-related organizations(KOSID, ICC, KlID), will be more than important.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.859-865
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• 2014

Optimization of an electric machine is mainly a nonlinear multi-modal problem. For the optimization of the multi-modal problem, many function calls are required with much consumption of time. To address this problem, this paper proposes a novel hybrid algorithm in which function calls are less than conventional methods. Specifically, the proposed method uses the kriging metamodel and the fill-blank technique to find an approximated solution in a whole problem region. To increase the convergence speed in local peaks, a parallel gradient assisted simplex method is proposed and combined with the kriging meta-model. The correctness and usefulness of the proposed hybrid algorithm is verified through a mathematical test function and applied into the practical optimization as the cogging torque minimization for an interior permanent magnet synchronous machine.

• Journal of Korean Society of Steel Construction
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• v.10 no.1 s.34
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• pp.115-123
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• 1998

In design of tall buildings, the flows of stress and ultimate strength of structures cannot be obtained by the elastic analysis alone. The current inelastic analysis are very impractical for practical engineer due to the amount of work involved in engineering calculation. In this paper the PC-based inelastic analysis by the residual strength ratio concepts is introduced. The efficiency of inelastic analysis is evaluated by comparing the results of inelastic analysis with those of elastic analysis for the existing tall buidling located in Seoul. Some modification in terms of lateral resisting structural system is proposed to improve the system ductility.

• Journal of Theoretical and Applied Mechanics
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• v.1 no.1
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• pp.97-109
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• 1995

In this paper, a finite viscoelastic continuum model for rubber and its finite element analysis are presented. This finite viscoelatic model based on continuum mechanics is an extended model of Johnson and Wuigley's 1-D model. In this extended model, continuum based kinematic measures are rigorously defied and by using this kinematic measures, elastic stage law and flow rule are introduced. In kinematics, three configuration are introduced. In kinematics, three configuration are introduced. They are reference, current and virtual visco configurations. In elastic state law, it is assumed that at a certain time, there exists an elastic potential which describes the recoverable elastic energy. From this elastic potential, elastic state law is derived. The proposed flow rule is based on phenomenological observation. The flow rule gives precise relaxation response. In finite element approximation, mixed Lagrangian description is used, where total and similar method of updated Lagrangian descriptions are used together. This approach reduces the numerical job and gives simple nonlinear syatem of equations. To satisfy the incompressible condition, penalty-type modified Mooney-Rivlin energy function is adopted. By this method nearly incompressible condition is obtain the virtual visco configuration. For verification, uniaxial stretch tests are simulated for various stretch rates. The simulated results show good agreement with experiments. As a practical experiments. As a preactical example, pressurized rubber plate is simulated. The result shows finite viscoelastic effects clearly.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.3
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• pp.129-134
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• 2020

The current evaluation time period for the construction management service is the project completion or after project completion. Therefore, the construction manager has the following problems. First, it is difficult to prepare the evaluation due to the new field movement of the existing participating engineer. Next, the CM work is complex as well as extensive. Therefore, the critical success factors of the construction technology services evaluation are required as a systematic performance standard of CM work. In this study, we extracted the critical success factors that can systematically prepare the evaluation from the early stage of the project through in - depth interviews with experts. And, this study was analyze the priority of each factor by using AHP technique. As a result, the most important factors were related to the systemization of the preparation process, the construction manager work capabilities and practical construction management. And the priorities of all factors were analyzed high in the factors suggested by the owner groups. The results of this analysis are expected to provide the standards that construction management service performer carry out structured management of construction management throughout the project.

• Computers and Concrete
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• v.31 no.5
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• pp.371-384
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• 2023

Precast roofing systems employing prestressed elements often serve as smart structural solutions for the construction of industrial buildings. The precast concrete elements usually employed are highly engineered, and often consist in thin-walled members, characterised by a complex behaviour in fire. The present study was carried out after a fire event damaged a precast industrial building made with prestressed beam and roof elements, and non-prestressed curved barrel vault elements interposed in between the spaced roof elements. As a consequence of the exposure to the fire, the main elements were found standing, although some locally damaged and distorted, and the local collapse of few curved barrel vault elements was observed in one edge row only. In order to understand and interpret the observed structural performance of the roof system under fire, a full fire safety engineering process was carried out according to the following steps: (a) realistic temperature-time curves acting on the structural elements were simulated through computational fluid dynamics, (b) temperature distribution within the concrete elements was obtained with non-linear thermal analysis in variable regime, (c) strength and deformation of the concrete elements were checked with non-linear thermal-mechanical analysis. The analysis of the results allowed to identify the causes of the local collapses occurred, attributable to the distortion caused by temperature to the elements causing loss of support in early fire stage rather than to the material strength reduction due to the progressive exposure of the elements to fire. Finally, practical hints are provided to avoid such a phenomenon to occur when designing similar structures.

• The Journal of Korean Institute for Practical Engineering Education
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• v.3 no.2
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• pp.11-17
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• 2011

As a rapid rate of social change and competitive, paradigm of industry environment manufacturing products and services is shifted. Engineers design, develop, manufacture the products and services are strongly asked competency of different new creative practices. This means while industrial structure has been shifted from mass production to various allied production and social engineering based production, qualifications of engineers are required to individual creative competency as alternatives. In order to improve the competency, engineer become the creative people have ability to develop the professional knowledge competency and expand the competency to convergence the new product and services with sensing the life and social structure shift, human engineering, psychology, and emotion. For the competency, we develop the training program "improving convergence, creativity through Art." we intend that the program should be composed of creative engineering mechanism combined creative arts mechanism. It has been operated to the engineers for 17 weeks. we will discuss the program result and research direction and utilization in depth.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.33-47
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• 2007

In a practical engineering, the equivalent static analysis (E.S.A) and the response spectrum analysis (R.S.A) are generally used for the seismic analysis. The base shears obtained from the E.S.A are invariable no matter how the principal axes of building structures are specified on an analysis program while those from the R.S.A are variable. Accordingly, the designed member size may be changed by how an engineer specify the principal axes of a structure when the R.S.A is used. Moreover, the base shears in the normal direction to the excitation axis are sometimes produced even when an engineer performs a response spectrum analysis in only one direction. This tendency makes the base shear, which is used to calculate the scale-up factor, relatively small. Therefore the scale-up factor becomes larger and it results in uneconomical member sizes. To overcome these disadvantages of the R.S.A, an alternative has been proposed in this study. Three types of example structures were adapted in this study, i.e. bi-direction symmetric structure, one-direction antisymmetric structure and bi-direction antisymmetric structure. The seismic analyses were performed by rotating the principal axes of the example structures with respect to the global coordinate system. The design member forces calculated with the scale-up factor used in the practice were compared with those obtained by using the scale-up factor proposed in this study. It can be seen from this study that the proposed method for the scale-up factor can provide reliable and economical results regardless of the orientation of the principal axes of the structures.

• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.19-25
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• 2022

This study examined the impact of direct structured approach of students who demonstrate little or no sense of basic engineer concepts in physics courses. This direct structured instruction is one of the methodologies that focuses on explicit and systematic practices in which an instructor set clear learning outcomes and clarifies the direction of the instruction. 90 participants were randomly selected and tested on the areas of problem-solving skills, reasoning, working memory, and processing speed. 20% of the participants were found to be students with basic engineering disabilities. On the other hand, in the direct structured group, 51.7% and 58.0% of the sample group (90 students) showed a 6.3% increase from the mid-term to final examinations, respectively. The subgroups with 50% or lower grades were decreased from 26.7% to 24.5%. However, five students with the lowest grade of 20% were selected as students with learning disabilities in the study and the average scores of mid-term and final exams were increased by 8.6%, which was 17.9% and 26.5%, respectively at the end of the study. As a result, it showed that direct structured approach for students with learning disabilities in the engineer concepts was effective.