• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.133-146
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• 2006

Collaborative optimization (CO) is a multi-level decomposed methodology for a large-scale multidisciplinary design optimization (MDO). CO is known to have computational and organizational advantages. Its decomposed architecture removes a necessity of direct communication among disciplines, guaranteeing their autonomy. However, CO has several problems at convergence characteristics and computation time. In this study, such features are discussed and some suggestions are made to improve the performance of CO. Only for the system level optimization, genetic algorithm is used and gradient-based method is used for subspace optimizers. Moreover, response surface models are replaced as analyses in subspaces. In this manner, CO is applied to aero-structural design problems of the aircraft wing and its results are compared with the multidisciplinary feasible (MDF) method and the original CO. Through these results, it is verified that the suggested approach improves convergence characteristics and offers a proper solution.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.503-508
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• 2019

In recent years, among the IoT products that are used in various ways in everyday life, motorized products are increasing. This study aims to develop a microcontroller unit that can easily control multiple motors and develop an application that makes use of this microcontroller unit. The basis of the hardware developed by the research was the Arduino board, and to it, the Bluetooth module, Zigbee module, and a motor driver were connected. To control the device, an application was designed. The final microcontroller unit and its application may be applied to electric curtains, electric blinds, robots, and other various IoT products. Further research will lead to hardware development that can control various types of motors other than stepping motors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2294-2300
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• 2013

As smartphones have become widely used, topics of smartphone become a hot research subject in IT technologies. Many applications have been developed for the smartphone and the application market has become more and more increasing. However here are few studies or application developments on Korea's traditional games. In this paper we developed Korea's traditional board game Gonu. People who are young or old can play the game. We expect that many applications which related with Korean culture are developed on the smartphone environment.

• Journal of Digital Convergence
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• v.18 no.3
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• pp.305-310
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• 2020

Lately the increase of unemployment and freeters, the use of mobile applications for part-time jobs has been increasing. This study identifies the problems of mobile job applications and focuses on domestic applications: 'Albamon' and 'Albachunkuk'. By conducting surveys and in-depth interviews based on Peter Morville's Honeycomb model. The usability assessment, the proposed improvement results are as follows: First, unhealthy establishments and overlapping job blocking filters should be further strengthened. Second, a design to tailor to the 20s age group, who are the main user of the application, is needed. Third, a fully customized part-time job listing is needed for users on the application landing page. Fourth, the application requires verification procedures for the document preparation regarding work contracts and reporting of employers. This study hopes to add to the improvement of job-seeking application services in Korea.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.5
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• pp.456-464
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• 2014

Commercial vehicle drivers typically feel more fatigued compared to general-public drivers. because they spend longer periods of time driving and experience more rough road conditions. This study showed that the application of a magnet, a linear spring, and a seat suspension with nonlinear characteristics was the optimal design to increase comfort while driving. The resonant frequency for the optimal design suspension was 2.8 Hz, and the stiffness was analyzed through displacement-load experiments. Vibration transmissibility was analyzed by suspension stiffness and the existing dynamic compression. The magnetic spring type was at 0.875. As a result, the X-type magnetic spring performed better than the existing spring at 0.729.

• Journal of Institute of Convergence Technology
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• v.5 no.2
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• pp.33-36
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• 2015

In this paper, the development history of random packings for several generations was briefly introduced. We demonstrate the application of 3D printing to the fabrication of Pall rings, directly using computer aided design (CAD) models. The CAD was used to design Pall rings with different number of blades. The models were then printed by using UV curing of acrylonitrile-butadiene-styrene (ABS) resins. The results show that 3D printing is a promising method for producing precisely controlled packing materials. It is also expected that 3D printing is helpful for the fundamental studies of highly efficient packing materials with complex geometrical shapes.

• Journal of Institute of Convergence Technology
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• v.11 no.1
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• pp.39-42
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• 2021

2차원 유동장내 수직 진동하는 원통의 Von Karman 와열 유동 현상에 대한 진동 주파수 계산 문제는 진동하는 물체의 비정상 공력 해석 연구 검증에 많이 사용하는 고전적 방법이다. 본 연구에서는 오픈소스 OpenFoam 기반의 중첩격자 기법을 사용하여 층류 유동장내의 수직방향 진동하는 원통 주변의 비정상 유동 현상과 원통 벽면에서의 공력 특성 변화를 해석하기 위한 일련의 해석 단계들과 결과를 타 연구그룹과 비교하였다. 원통 형상과 진동에 의한 와열 유동의 주기적 유동 특성과 복잡성 해석의 건전성을 확보하기 위하여 격자와 시간제어에 대한 해의 정확도에 미치는 영향을 평가하였다. 본 연구에서 수행한 해석 방법은 일관성과 신뢰성 있는 해석 결과들 보여주었으며, 향후 보다 실제적인 진동하는 에어 포일의 비정상 공력 해석 연구에 적용 가능함을 확인하였다.

• Journal of Digital Convergence
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• v.18 no.11
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• pp.233-239
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• 2020

Due to the development of digital technology, users can record their daily lives without being restricted by time and space. The trend is growing rapidly, but lifelogging cases are still insufficient. Google's Timeline and domestic application 'Daily' were analyzed through in-depth interviews. Based on the Creating Pleasurable Interface Model, the factors influencing user satisfaction were identified by the Reckard 7-point scale based on the Honeycomb model. The results of the in-depth interviews and the 7-point scale were similar, and we could see what and why users preferred the recording application. This study is meaningful to evaluate the user experience for recording application and analyzing the needs of users obtained through in-depth interviews to assess the usability that provide a service record and recall.

• Journal of Korea Multimedia Society
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• v.22 no.5
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• pp.601-612
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• 2019

As the $4^{th}$ industrial revolution is accelerating, IT convergence application technologies are attracting attention in various fields. In the manufacturing industry, Smart Factory technology, which is blended with IT technology, has been developed to solve the problem casued by the decrease of the labor force, and a monitoring server is required to remotely control the equipment or to inquire about the operation status of the factory. In this paper, we designed and implemented RESTful API for data sharing between factory equipment and monitoring server in Smart Factory. In order to verify the designed API, a testbed was operated for an actual plastics manufacturing plant. As a result, it was confirmed that the testbed can be operated normally in actual operating environment.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.153-160
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• 2018

This study suggests the development and the application of cognitive apprenticeship to instructional design for the 'computer and presentation skill' among the liberal arts computer courses in H university. The purpose of this paper is to show effects of instructional design on learning of the liberal arts computer courses employing cognitive apprenticeship, and examine earner's satisfaction of instructional planning, lecture contents, and teaching methods, which are evaluation elements of the content evaluation area. As a result of the study, cognitive apprenticeship theory has improved the satisfaction of the lesson plan, lecture contents and teaching method. Therefore, this study has significance in that it recognizes that cognitive apprentice theory is effective for general computer class. It is expected that it will be applied to effective teaching methods of liberal arts computer related subjects in the future.