• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.11
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• pp.973-981
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• 2013

The main role of an acoustic diffuser is to diffuse reflected sound field spatially. Since the pioneering work of Schroeder, there have been investigations to improve its performance by using shape/sizing optimization methods. In this paper, a gradient-based topology optimization algorithm is newly presented to find the optimal distribution of reflecting materials for maximizing diffuser performance. Time-harmonic acoustic analysis in a two-dimensional acoustic domain is carried out where the domain is discretized by finite elements. Perfectly matched layers are placed to surround the domain to simulate non-reflecting boundary conditions. Design variables are assigned to each element of which material properties are interpolated between those of air and those of a rigid body. An approach to extract the reflected field from the total acoustic field is employed. To validate the effectiveness of the proposed method, design problems are solved at different frequencies. The performance of the optimized diffusers obtained by the proposed method is compared against that of the conventional Schroeder diffusers.

• Journal of Engineering Education Research
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• v.20 no.1
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• pp.18-27
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• 2017

This study aims to investigate industry needs for convergence education in the field of nano-technology, bio-technology, robot, and design. Firstly, the area of convergence technology in nano-tech, bio-tech, robot, and design fields was examined through the literature review and case study. The areas were validated by the experts review who consisted of four industry experts and four professors in the relevant fields. Second, a questionnaire was developed for investigating industry's needs on convergence education. The questionnaire consisted of three parts: 1) awareness of necessity for convergence education, 2) the needs for convergence new technology education from the perspective of industry, and 3) opinions on convergence education. The questionnaire was validated by three engineering education experts. Third, the survey was conducted in cooperation with the Sector Council of Industrial Resources. A total of 400 respondents responded to the questionnaires: 98 in the nano-technology field, 74 in the design field, 58 in the robotics field, and 170 in the bio-technology field. Fourth the industry needs for convergence education were analyzed and implications were suggested. The results of this study are expected to provide a guideline for developing convergence education programs in higher education.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.3
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• pp.101-106
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• 2001

Air-cored superconducting synchronous generator(ASSG) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, in the case of the shape optimum design of ASSG, other design variables different from an iron-cored machine should be considered, which will lead to substantial improvement on the performance. The major design variables that are considered by using Three-dimensional Finite element Method(3D FEM) in this paper are : 1) field coil width, 2) axial length of magnetic shield, and 3) armature winding method. End-ring of armature winding is considered in the calculation of EMF. When it comes to field coil width, as field coil width enlarges, its effective field increases but the maximum field on the superconductor decreases. this determines the critical current density. this study presents an effective field coil width, axial length of magnetic shield, and armature winding method, and also the analysis is verified by the experimental results.

• Journal of Computational Design and Engineering
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• v.2 no.3
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• pp.129-136
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• 2015

This paper proposes a novel method for shape design of a Bezier surface with given boundary curves. The surface is defined as the minimizer of an extended membrane functional or an extended thin plate functional under the guidance of a specified normal field together with an initial prescribed surface. For given boundary curves and the guiding normal field, the free coefficients of a Bezier surface are obtained by solving a linear system. Unlike previous PDE based surface modeling techniques which construct surfaces just from boundaries, our proposed method can be used to generate smooth and fair surfaces that even follow a specified normal field. Several interesting examples are given to demonstrate the applications of the proposed method in geometric modeling.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.421-430
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• 2000

This paper describes an optimal design method which is applied a weighted least square (WLS) method for Magnetic Resonance Imaging (MRI) system. An optimal design approach is presented for a homogeneity superconducting magnet with the superconducting active shield especially for a magnetic resonance imaging system. The WLS is used to obtain the optimal configurations using the least amount and minimum volume of conductor, exhibiting the smallest level of field inhomogeneity and resulting in the least level of stray field. The proposed model is used to design a multiple-shield configuration for a 1.5 T MRI magnet. The field homogeneity is required less than 5 gauss stray field contour within 4m axially and 3m radially from origin. The designed magnet with the actively magnetic shielding coil out of main coils is analyzed by FEM and theoretical analysis method, investigated the field homogeneity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2732-2741
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• 2000

Combination of magnetic recording technology and optical recording technology such as Near Field Optical Recording is watched recently. In order to accomplish this technology, the development of an electromagnetic driven mm-sized mirror shifting laser beam in track direction have to needed. In Near Field Optical Recording System, shifting laser beam in track direction mean as fine tracking and means as coarse tracking. Therefore in Near Field Optical Recording, 2-stage actuator is composed of servo controller in reading or recording information on disc layer. In our research, through design and simulation process of driven mm-sized mirror, we arrange systematically design process of driven mm-sized mirror having good frequency transfer characteristics. Design and simulation processes included modal analysis of spring, calculation of magnetic moment according to the number of turns and geometric configuration of coil and magnetic circuit analysis meaning that calculation of magnetic flux density in air gap of magnetic circuit. After that we design and make parts of driven mm-sized mirror, assemble and evaluate our electriomagnetic driven mm-sized mirror. we compared design values with actual characteristic values and present solution scheme. Through these processes we performed manufacturing of an electromagnetic driven mm-sized mirror having good frequency-domain characteristics and high sensitivity characteristics.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.23 no.1
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• pp.299-316
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• 2012

The purpose of this study is to effectively provide professors in the design field with information services by identifying their information use behaviors. Data were collected by distributing questionnaires after dividing the specialties of 110 professors in the design field into 4 areas. The results were made in terms of purposes of use and the acquisition channels, types of information sources, difficulties of information acquisition and the library use of the institution. Some suggestions were shown as follows: collection of gray literatures such as exhibition data, seminar data, reports and pamphlets, purchase of web databases in design field, information literacy education including the use of domestic and foreign design databases for the professors and the construction of web directories on the library web sites.

• Transactions of the Society of Information Storage Systems
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• v.2 no.1
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• pp.65-70
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• 2006

In the information storage development, the trend of the storage device is to increase the recording density. Among such an effort, near-field probe recording is spotlighted as a method of high increasing recording density. For the successfully embodiment of storage device, the actuating mechanism of near-field probe is essentially designed. In this paper, we suggest the slider similar with conventional HDD and design the slider using near-field probe for the purpose of applying the slider in order to control gap between probe and media. The most important object of slider design is to guarantee the flying ability and stability. For achievement of these design objects, we perform two step of optimal design process. The media is supposed to model as random displacement, which is only considered roughness of disk surface. The design slider is analyzed with dynamic state in assumed media. At this process, the optimal model is confirmed to stable flying stability.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.171-176
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• 2005

In the information storage development, the trend of the storage device is to increase the recording density. Among such an effort, near-field probe recording is spotlighted as a method of high increasing recording density. For the successfully embodiment of storage device, the actuating mechanism of near-field probe is essentially designed. In this paper, we suggest the slider similar with conventional HDDs and design the slider using near- field probe for the purpose of applying the slider in order to control gap between probe and media. The most important object of slider design is to guarantee the flying ability and stability. For achievement of these design objects, we perform two step of optimal design process. The media is mod! eled as random displacement, which is only considered roughness of disk surface. The design slider is analyzed with dynamic state in assumed media. At this process, the optimal model is confirmed to stable flying stability.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.6-11
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• 2020

In today's world, the design industry is becoming more complex, with the development of networks such as the internet and revolutionary changes in information and telecommunications. As the demand for designers to cope with various situations occurring in these industrial sites or solve problems in practice promptly is required, a capstone design program was developed in collaboration with the industry. Capstone design classes have positive effects on creative problem solving ability, academic achievement and learning satisfaction by allowing students to think and experience the practical problems of the industrial field. It is also effective in improving communication, creative thinking and critical thinking. The purpose of this study is to search for talent training methods needed in the fashion industry and to develop effective programs through capstone design class studies conducted in the fourth grade of fashion design majors from 2017 to 2019 (6 semesters). Through these studies, the aim is to search for talent training methods needed in the fashion industry and to develop effective programs. If the capstone design learning method is used as a method of solving problems through close communication between the company and the educational field as an industry-academia cooperation system, it is expected to be positioned as a field-type human resource education method that is required in the industrial field.