• 공학교육연구
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• 제1권1호
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• pp.21-26
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• 1998

최근에 대학에서 교수들의 강의능력을 향상시킬 필요성을 인식하는 추세가 점차로 높아지고 있다. 고등교육에서 교육의 수월성이 요청되는 까닭은 곧 정보화 시대의 국가 경쟁력은 전적으로 대학 졸업생의 능력에 따라 좌우되기 때문이다. 이 논문은 미국에 있는 네 개의 공과대학-Michigan대학교, Purdue 대학교, Cornell 대학교, Michigan 공과대학교-에서 교수와 대학원생(교수 희망)을 대상으로 실시되는 공학교육 프로그램을 검토하고 비교한다. 이들 네 대학교는 학교 유형(사립 또는 공립, 교육중심-또는 연구중심)과 학교 규모의 관점에서 다양한 양상을 갖고있는 대학이다. 공학교육의 실시목적은 유사하지만, 교육이수 대상자, 교육내용 및 평가기준, 담당교수 선정 등에서 대학마다 차이가 나타난다. 결론으로, 공학교육의 도입을 검토할 때는 반드시 대학교 자체의 특성 내지 대학 발전방향을 감안해서 공학교육 프로그램을 계획할 것을 제시한다.

• 공학교육연구
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• 제26권1호
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• pp.37-44
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• 2023

Recently, the Internet of Things is attracting attention as an important key technology of the 4th Industrial Revolution, and SW education using physical computing is suggested as a good alternative to supplement the problems raised by beginners in programming education. Among the many teaching tools that can be used for physical computing education, MODI is a modular manufacturing tool that anyone can easily assemble like Lego. MODI is a teaching tool that can improve learners' achievement by linking a self-linked block-type code editor called MODI Studio to lay the foundation for programming in a relatively small amount of time and immediately check the results in person. In this paper, a physical computing education method using MODI was designed to be applied to basic programming courses for programming beginners and applied to after-school classes for middle school students. As a result, it was found that students' interest and satisfaction were much higher in physical computing classes using MODI than in text-based programming classes. It can be seen that physical computing education that allows beginners to see and feel the results in person is more effective than grammar-oriented text programming, and it can have a positive effect on improving basic programming skills by increasing students' participation.

• 공학교육연구
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• 제24권2호
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• pp.20-28
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• 2021

In 2020, the COVID-19 pandemic has brought dramatic changes in the field of engineering education. Contrary to the traditional engineering education emphasis on content-oriented, design-based, hands-on, experimental, and field experience, most of engineering classes in 2020 had to be undertaken remotely online. However, it has not been explored how professors and students perceive about such a shift in engineering education. The aim of the current study was to investigate the perceptions of professors and students on online classes in engineering colleges during spring Semester 2020. Questionnaire data were collected from 100 professors and 4,152 students in the college of engineering. The results of this study were as following: Students were less satisfied with the online classes than professors. The online lecture method that students were most satisfied with was the recorded lecture. This is likely due to the fact that the recorded lectures can be repeated multiple times anytime, anywhere. Moreover, the experimental classes, which conventionally has more of an emphasis on the hands-on experience, also had to be conducted remotely, showing even lower satisfaction among students. Most of professors reported that the average hours they spent on preparing for online lecture increased compared to face-to-face class. Both professors and students preferred in-person exam as a desirable method of end-of-semester assessment for grading. The results of the current study have important implications for the improvement of online course environments. It is important for professors to design a structured class suitable for online education and understand the challenges students encounter during online classes. Also, professors should communicate more openly about their expectations and rubrics for class goals and assignments. Schools also needs to make effort to provide the support for the internet environment of students.

• 대한의용생체공학회:의공학회지
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• 제29권1호
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• pp.52-58
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• 2008

The object of this study is to investigate the effects of intermittent cyclic stretching on the smooth muscle cells (SMCs) seeded onto aligned multi-layered fibrous scaffold. To make multi-layered fibrous scaffold, polyurethane (PU) and poly(ethylene oxide) (PEO) were electrospun alternatively, then were immersed into distilled water to extract PEO. Various types of scaffolds were fabricated depending on fiber directions, i.e., aligned or randomly oriented. The direction of stretching was either parallel or vertical to the fiber direction for the aligned scaffolds. The stretching was also applied to the randomly aligned scaffolds. The duration of stretching was 2 min with 15 min resting period. During the stretching, the maximum and minimum strain was adjusted to be 10 and 7%, respectively with the frequency of 1 Hz. The bioactivities of cells on the scaffolds were assessed by quantifying DNA, collagen, and glycosaminoglycan (GAG) levels. And the cell morphology was observed by staining F-actin. SMCs under parallel stretching to the fiber direction responded more positively than those in other conditions. From the results, we could explain the morphological effect of a substrate on cellular activities. In addition the synergistic effects of substrate and mechanical stimuli effects were confirmed.

• 한국재료학회지
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• 제15권1호
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• pp.25-30
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• 2005

The microstructural changes by hot extrusion of AZ31B magnesium alloy were observed, and the relation to the tensile property was examined. The tensile properties as oriented longitudinal(L), half transverse(HT) and long transverse(LT) to the extrusion direction were investigated at $20^{\circ}C,\;100^{\circ}C,\;200^{\circ}C,\;300^{\circ}C\;and\;400^{\circ}C$, respectively. As the results, many recrystallized small grains distributed uniformly in large banded microstructures formed along the extrusion direction. The grain size of as-extruded specimen was around $30\~150\;{\mu}m$. As increasing the test temperature the tensile and yield strength with respect to the angle between the axis of the tensile and the longitudinal direction in extrusion was decreased, but their elongation were increased and their deviation between L and LT specimens have disappeared from $300^{\circ}C$. This mechanical anisotropy was reduced at elevated temperatures and almost disappeared at $400^{\circ}C$. It was considered that the homogenization was occured by the recrystallization and the change of slip system was occurred during tensile test process in elevated temperatures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권7호
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• pp.1807-1822
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• 2023

Innovation and rapid increased functionality in user friendly smartphones has encouraged shutterbugs to have picturesque image macros while in work environment or during travel. Formal signboards are placed with marketing objectives and are enriched with text for attracting people. Extracting and recognition of the text from natural images is an emerging research issue and needs consideration. When compared to conventional optical character recognition (OCR), the complex background, implicit noise, lighting, and orientation of these scenic text photos make this problem more difficult. Arabic language text scene extraction and recognition adds a number of complications and difficulties. The method described in this paper uses a two-phase methodology to extract Arabic text and word boundaries awareness from scenic images with varying text orientations. The first stage uses a convolution autoencoder, and the second uses Arabic Character Segmentation (ACS), which is followed by traditional two-layer neural networks for recognition. This study presents the way that how can an Arabic training and synthetic dataset be created for exemplify the superimposed text in different scene images. For this purpose a dataset of size 10K of cropped images has been created in the detection phase wherein Arabic text was found and 127k Arabic character dataset for the recognition phase. The phase-1 labels were generated from an Arabic corpus of quotes and sentences, which consists of 15kquotes and sentences. This study ensures that Arabic Word Awareness Region Detection (AWARD) approach with high flexibility in identifying complex Arabic text scene images, such as texts that are arbitrarily oriented, curved, or deformed, is used to detect these texts. Our research after experimentations shows that the system has a 91.8% word segmentation accuracy and a 94.2% character recognition accuracy. We believe in the future that the researchers will excel in the field of image processing while treating text images to improve or reduce noise by processing scene images in any language by enhancing the functionality of VGG-16 based model using Neural Networks.

• Journal of the Korean Wood Science and Technology
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• 제36권2호
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• pp.1-8
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• 2008

This study was performed to evaluate the burning characteristics of wood-based materials and the effect of surface treatment of fire retardant using cone calorimeter. Four types of wood-based materials, such as Plywood, Oriented Strand Board (OSB), Particle Board (PB) and Medium Density Fiberboard (MDF), were tested at a constant heat flux of $50kW/m^2$ to investigate the time to ignition, mass loss rate, heat release rate, effective heat of combustion, etc. In addition, each type of wood-based material was tested at the same heat flux after fire retardant treatment on the surface to evaluate the effect of this treatment on the burning characteristics. The surface treatment of fire retardant, by the amount of $110g/m^2$, delayed the time to ignition almost twice. However, it was indicated that heat release rate, mass loss rate, and effective heat of combustion were not significantly affected by fire retardants treatment for all types of wood-based materials.

• 한국안광학회지
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• 제10권3호
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• pp.193-203
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• 2005

Zn-나프텐산염을 출발 원료로 사용하고 스핀코팅 - 열분해법을 이용하여 실리카 유리 위에 c축으로 배향된 나노 결정질 ZnO 박막을 제조하였다. X-선 회절 분석을 행한 결과, 모든 시편에서 ZnO (002) 피크만이 관찰되었으며, 박막의 열처리 온도가 증가함에 따라 (002) 피크 강도가 증가하였다. 박막의 표면 미세 구조는 매우 균질하였으며, 입자들 간의 응집은 관찰되지 않았다. 박막의 topology를 주사형 탐침 현미경으로 분석한 결과에 따르면, 실리카 기판 자체의 불균질한 표면 특성과 ZnO 입자의 c축 배향 특성에 의한 것으로 보이는 3차원적인 입자성장이 모든 열처리 온도 영역에 대해 박막의 표면에서 관찰되었다. 고배향된 박막들 중에서 $800^{\circ}C$로 열처리한 박막의 표면이 가장 균질한 특성을 나타내었다. 박막의 가시영역에서의 투과율은 $1000^{\circ}C$로 열처리한 박막을 제외하고 모든 박막에 있어서 80% 이상의 투과율을 나타냈으며, 380~400nm 영역에서 날카로운 absorption edge가 나타났다. 흡수피크를 이용하여 계산된 오든 박막의 에너지 밴드 캡은 ZnO 단결정 및 다른 연구자들에 의해 보고된 박막과 같은 영역에 존재하였다. 본 연구에서 제조된 ZnO 박막들 중에 치밀한 입자 성장과 균질한 표면 특성을 보이는 $600^{\circ}C{\sim}800^{\circ}C$로 열처리된 박막은 UV차단성 투명전도막 및 렌즈 등의 광학소자에 실질적인 응용이 기대 된다.

• 산업경영시스템학회지
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• 제42권3호
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• pp.8-14
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• 2019

Most of the data envelopment analysis (DEA) models evaluate the relative efficiency of a decision making unit (DMU) based on the assumption that inputs in a specific period are consumed to produce the output in the same period of time. However, there may be some time lag between the consumption of input resources and the production of outputs. A few models to handle the concept of the time lag effect have been proposed. This paper suggests a new multi-period input DEA model considering the consistent time lag effects. Consistency of time lag effect means that the time delay for the same input factor or output factor are consistent throughout the periods. It is more realistic than the time lag effect for the same output or input factor can vary over the periods. The suggested model is an output-oriented model in order to adopt the consistent time lag effect. We analyze the results of the suggested model and the existing multi period input model with a sample data set from a long-term national research and development program in Korea. We show that the suggested model may have the better discrimination power than existing model while the ranking of DMUs is not different by two nonparametric tests.

• 디지털융복합연구
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• 제13권2호
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• pp.115-120
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• 2015

디지털융합 환경의 기반 기술인 클라우드 컴퓨팅이 확산되면서 개인정보보호가 중요한 이슈로 대두되고 있다. 국내 개인정보보호법에서도 개인정보처리자가 클라우드 컴퓨팅을 통해 개인정보를 처리하는 경우, 계약서 또는 서비스 수준 협약(SLA, Service Level Agreement) 작성을 명시하고 있으나 일반적인 클라우드 SLA에서는 주로 가용성 측면의 지표가 포함되어있으며 개인정보보호에 대한 지표는 찾아보기 어렵다. 본 논문에서는 클라우드 환경에서의 개인정보보호 대책 분석 및 SMART 모델 활용을 통해 SLA에 포함할 수 있는 총 7개의 개인정보보호 지표와 13개의 척도를 개발하였다. 도출 된 지표는 전문가 그룹을 대상으로 포커스 그룹 인터뷰를 실시하여 중요도 및 실현 가능성을 평가하였다. 본 논문은 클라우드 환경에서의 개인정보보호 대책 확립과 향후, 개인정보보호 수준 측정을 위한 자료로 활용될 것으로 기대된다.