• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.903-904
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• 2010

• Journal of Broadcast Engineering
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• v.27 no.2
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• pp.228-239
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• 2022

In this paper, we propose an unmanned vehicle scratch detection deep learning model for car sharing services. Conventional scratch detection models consist of two steps: 1) a deep learning module for scratch detection of images before and after rental, 2) a manual matching process for finding newly generated scratches. In order to build a fully automatic scratch detection model, we propose a one-step unmanned scratch detection deep learning model. The proposed model is implemented by applying transfer learning and fine-tuning to the deep learning model that detects changes in satellite images. In the proposed car sharing service, specular reflection greatly affects the scratch detection performance since the brightness of the gloss-treated automobile surface is anisotropic and a non-expert user takes a picture with a general camera. In order to reduce detection errors caused by specular reflected light, we propose a preprocessing process for removing specular reflection components. For data taken by mobile phone cameras, the proposed system can provide high matching performance subjectively and objectively. The scores for change detection metrics such as precision, recall, F1, and kappa are 67.90%, 74.56%, 71.08%, and 70.18%, respectively.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.449-456
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• 2012

The college students who have relatively weak academic background feel more difficult in learning programming language grammars and programming skills in introductory course. At the end of semester, most of students had the negative attitude to programming and only a few students could write the programs for the given problems because they spent most of time to learn grammars instead of learning problem solving skills and logics. In this study, we propose to use Scratch in introductory programming course to help students to understand grammars and problem solving skills. It's necessary to educate first-time programmers how to solve the problems before they learn grammars of the programming language in their first programming language course. This paper shows that Scratch allows students not only to learn problem solving skills in programming but also to motivate students themselves in the class.

• 한국정보교육학회:학술대회논문집
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• 2010.08a
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• pp.211-219
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• 2010

In this paper we used Scratch, educational programming language, to teach algorithm to elementary school students. Scratch provides a graphical programming interface, so elementary school students can learn easily and immediately check the results of programming that can hold students' interest. Therefore, development of training material from Scratch using the algorithm can look forward to the Bloom's Mastery Learning. Also worksheets by level will give us excellence in education, growth of the ability to solve problems and creativity will be a great asset for student's future learning.

• The KIPS Transactions:PartA
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• v.15A no.5
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• pp.269-274
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• 2008

Recently, lots of embedded processors which can run streaming multimedia with high resolution display are introduced. Among the applications running on these embedded processors, real-time audio streaming is one of the applications that suffer from the lack of energy and memory space. In this paper, we propose a novel data compression method on scratch-pad memory, which saves both useful space on the scratch-pad memory and energy. We have implemented the data compression scheme on the GDM1202 real-time audio streaming processor, and the performance results show that we obtained 13.3% energy saving while maintaining comparable application performance to that of the non-compression case.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.134-140
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• 2002

Chemical mechanical polishing of aluminum and photoresist using colloidal silica-based slurry was experimented. The effects of slurry pH, silica concentration, and oxidizer ($H_2O_2$) concentration on surface roughness and removal rate were studied. The optimum slurry conditions for reduction of micro-scratch were investigated. The optimum chemical mechanical polishing with the colloidal silica-based slurry was compared with conventional chemical mechanical polishing with alumina-based slurry. Chemical mechanical polishing of the aluminum with the colloidal silica-based slurry showed improved result but chemical mechanical polishing of the photoresist did not. The improved result was comparative with that of chemical mechanical polishing with filtered alumina-based slurry which one of desirable methods to reduce the micro-scratch.

• Journal of the Korean Society for Heat Treatment
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• v.15 no.3
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• pp.118-126
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• 2002

TiCN thin films were deposited on tool steels at $510^{\circ}C$ by PECVD from a $TiCl_4+N_2+CH_4+H_2+Ar$ gaseous mixture. The microstructures and preferred orientation were investigated. The micro-scratch tests were performed using a system equipped with an acoustic emission sensor. Critical loads were determined to evaluate the adhesion of TiCN to substrate. The influences of the microstructures of substrates, double layered coatings, and coatings after nitriding(duplex coating) were investigated. The experimental results showed that the microstructures of substrates and double layered coating did not affect the critical loads considerably. By the duplex coating, critical loads were not always increased. In some cases, duplex coatings decreased critical loads significantly despite of absence of black layer. In this study, we tried to relate the results of scratch test to the residual stress analysis. Nitriding before the coating reduces the tensile residual stress in the film, which gives rise to low critical load in scratch test.

• Transactions of Materials Processing
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• v.22 no.2
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• pp.86-92
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• 2013

When stamping ultra-high-strength steel (UHSS), the phenomenon of galling, which corresponds to a transfer of material from the sheet to the tool surface, occurs because of the high contact pressure between tool and workpiece. Galling leads to increased friction, unstable interface conditions, scratches on the sheet and the tool surfaces and, eventually, premature tool surface failures. Therefore, a simple and accurate evaluation method for tool scratching is necessary for the selection of tool material and coating, as well as for a better optimization of process conditions such as blank holder force and die radius. In this study, the pin-on-disc (PODT) and pin-on-flat surface (POFST) tests are conducted to quantitatively evaluate scratch-related tool life for stamping of UHSS. The variation of the friction coefficient is used as an indicator of scratch resulted from galling. The U-channel ironing test (UCIT) is performed in order to validate the results of the friction tests. This study shows that the POFST test provides a good quantitative estimation of tool life based on the occurrence of scratch.

• Journal of The Korean Association of Information Education
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• v.15 no.4
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• pp.533-542
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• 2011

In this paper, we have selected traveling algorithms of Line-Tracer as the focused learning elements with the PBL-based programming instruction method. Line-Tracer traveling algorithm programming has been simulated using the Scratch EPL. Development of robot web courseware such as Line-Tracer can create an effective educational environment and also provide solutions for lack of environmental conditions, such as time or spatial factor restrictions and excessive expense issues; these are major obstacles to developing robot programming education. Finally, we analyzed the effects on growth of student's logical thinking and problem solving abilities by demonstrating the Scratch application courseware to the field of elementary education.

• Journal of The Korean Association of Information Education
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• v.14 no.4
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• pp.547-553
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• 2010

Lately, studies on the educational effectiveness of educational programming language which can reduce the learning burden of the learners have been conducted in the programming learning process. This study analyzed the effect of programming education on the learning motivation and academic achievement after training the programming education using Scratch and Dolittle on the preliminary elementary school teachers. As a result, the experimental group trained by Scratch programming education showed significantly higher achievement than the control group by Dolittle Programming. This result can be helpful in selecting educational programming language when the programming education will be trained to the preliminary elementary school teachers.