• 대한치과기공학회지
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• 제8권1호
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• pp.31-36
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• 1986

This treatise suggests the effective method for the dental laboratory technology teaching plan. It will present concrete practical steps for and audio-visual dental laboratory technology education approach. It will also help students to understand the dental laboratory theory and practice learned in the class and make use of it greatly in the field work. As follows: 1. Instructor should teach interestingly basic dental laboratory technology theory with illustrations and figures on the teaching method. 2. In practical traing class, instructor should teach every step, using audio-visual materials such as slides and video tapes/Instructor and his assist and should show an example to the students. 3. Instructor should make a standard and train the studtnes repeatedly until they come up to it. 4. Students should be skilled in every case through field work during their spare time and vacation. 5. Instructor should also teach job moral and manner to the students so that they can be adapted themselves to the social activities and be successful dental laboratory technician after graduation.

• Journal of Information Processing Systems
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• 제11권2호
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• pp.205-228
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• 2015

In this paper, we present a virtual laboratory platform (VLP) baptized Mercury allowing students to make practical work (PW) on different aspects of mobile wireless sensor networks (WSNs). Our choice of WSNs is motivated mainly by the use of real experiments needed in most courses about WSNs. These experiments require an expensive investment and a lot of nodes in the classroom. To illustrate our study, we propose a course related to energy efficient and safe weighted clustering algorithm. This algorithm which is coupled with suitable routing protocols, aims to maintain stable clustering structure, to prevent most routing attacks on sensor networks, to guaranty energy saving in order to extend the lifespan of the network. It also offers a better performance in terms of the number of re-affiliations. The platform presented here aims at showing the feasibility, the flexibility and the reduced cost of such a realization. We demonstrate the performance of the proposed algorithms that contribute to the familiarization of the learners in the field of WSNs.

• 대한공업교육학회지
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• 제38권1호
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• pp.125-143
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• 2013

이 연구의 목적은 기술 가정과 체험활동 수업을 위한 충청북도 중학교 기술실 현황과 활용 실태를 조사하기 위한 것이다. 첫째, 기술실의 보유 현황은 도시 지역이 69.84%, 읍면 지역이 33.38%로 두 지역 간의 기술실 보유 정도 차이가 컸고, 성립 형태별로는 국립학교 100%, 공립학교 86.24%, 사립학교 37.50%의 학교에서 기술실을 보유하고 있었고, 학급 수별은 10학급 미만인 학교는 35.59%, 10학급 이상 30학급 미만은 학교 62.11%, 31학급 이상인 학교에서는 85.71%로 차이가 나타났다. 기술실 규모에 대한 질문의 응답에는 근무 지역별, 설립 형태별, 성별 형태별로는 큰 차이 없이 교실 1칸($66m^2$) 넓이의 기술실이 62.12%로 나타났다. 기술실이 없는 이유를 조사한 결과, 기술실을 갖고 있었음에도 불구하고 기술실을 다른 공간으로 전환했다는 학교가 88.52%를 차지하고 있었다. 기술실이 없는 학교 중에서 앞으로 기술실의 설치 계획을 묻는 질문에 설치 계획이 있다고 응답한 학교는 5개교(8.19%)에 불과했다. 둘째, 기술실 활용 실태는 기술실 유형에 대한 질문에 종합 실습장이라는 응답이 대부분을 차지하였고, 기술실 활용 시간을 묻는 질문의 응답에 근무 지역별, 설립 형태별, 성별 형태별, 학급 수별에 큰 차이 없이 대부분의 학교에서 연중 1회에서 2회 정도를 활용하고 있다는 결과가 나왔다. 또한, 기술실 실습 수업의 배정 예산 결과를 살펴보면 학생 1인당 3천원 이상 5천원 미만이 36.36%로 가장 많은 비율을 차지했다.

• 대한치과기공학회지
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• 제34권4호
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• pp.413-421
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• 2012

Purpose: The purpose of this study is to investigate the improvement measure of dental technician practical examination. Methods: A survey was performed on 111 dental technicians who were self-written questionnaire. The results were analyzed by SPSS 12.0. The collected data was analyzed by frequency and chi-square test. Results: Questions most necessary work tools with the articulator was the highest with 55.9%, Electric wax carver(16.2%), heating clear(14.4%), CAD/CAM program(9.0%) was in the order. The need for additional practical test in response to actions included maxillary and mandibular comments occlusal work that you have to wax up the highest rate of 63.8%. Items most in need of improvement was strengthen of clinically oriented(48.0%), separation of written and practical(14.6%), control the degree of difficulty(11.4%) were the next order. Conclusion: Based on the results of this study, the current dental technician did not show major problems in the practical test. However, clinicians should be strengthened mainly. To do this, the use of the articulator is essential.

• 대한치과기공학회지
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• 제38권4호
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• pp.315-325
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• 2016

Purpose: This study investigated perception and plan of dental technologists regarding the old age and retirement for them to enjoy stable old age. Methods: Dental technologists working in Seoul, Incheon, and Gyeonggido were asked to fill out a self-administered questionnaire, and a total of 200 copies were used for analysis. The collected data were statistically analyzed by using SPSS 22.0(Statistical Package for Social Sciences. Chicago, IL, USA) (a=0.05). In order to compare perception toward old age preparation among the subjects, a Chi-square test was performed, and, to investigate the level of preparedness for old age according to general characteristics, t-test was performed. Results: In the analysis of the old age preparedness by age, there was a significant difference in financial preparation, Asset identification, use of retiring allowance, information gathering, senior town home, and stability (p<0.05). To the questions regarding perception toward retirement, the majority of the subjects (60.5%) answered they had thought about retirement, and many (23.9%) of them attributed the reason to job stress (23.9%). Regarding old age preparedness according to workplace, there was a significant difference in use of retirement allowance and education for old age preparedness between general dental laboratories and general hospitals (p<0.05). Conclusion: It is believed that, for preparation of dental technologists for stable old age, in addition to their personal effort, it is important to provide social support and practical measures to ensure welfare and retirement.

• 음성과학
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• 제8권1호
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• pp.159-165
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• 2001

In this paper, we make an experiment on speech recognition systems with barging-in and non-barging-in utterances. Barging-in capability, with which we can say voice commands while voice announcement is coming out, is one of the important elements for practical speech recognition systems. Barging-in capability can be realized by echo cancellation techniques based on the LMS (least-mean-square) algorithm. We use three kinds of telephone interface boards with barging-in capability, which are respectively made by Dialogic Company, Natural MicroSystems Company and Korea Telecom. Speech database was made using these three kinds of boards. We make a comparative recognition experiment with this speech database.

• Journal of Information Display
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• 제3권1호
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• pp.27-34
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• 2002

POS446M and POS430Ti alloys were investigated for application to a Flatron rail instead of conventional 28 wt%Cr alloy in order to reduce material costs. It was found that the permeability decrement of materials could be successfully minimized by proper heat treatment, and that the beam landing drift of the Flatron was not overly affected by the permeability of materials. In addition, the Flatron manufacturing process using POS430Ti was also stabilized without glass cracking by the application of the modified process conditions, which were optimized through the design of the experiment method.

• 한국세라믹학회지
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• 제56권4호
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• pp.331-339
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• 2019

While high-temperature ceramic composites consisting of carbides, borides, and nitrides, the so-called ultra-high-temperature ceramics (UHTCs), have been commonly produced through solid-state sintering, melt-solidification is an alternative method for their manufacture. As many UHTCs are binary or ternary eutectic systems, they can be melted and solidified at a relatively low temperature via a eutectic reaction. The microstructure of the eutectic composites is typically rod-like or lamellar, as determined by the volume fraction of the second phase. Directional solidification can help fabricate more sophisticated UHTCs with highly aligned textures. This review describes the fabrication of UHTCs through the eutectic reaction and explains their mechanical properties. The use of melt-solidification has been limited to small specimens; however, the recently developed laser technology can melt large-sized UHTCs, suggesting their potential for practical applications. An example of laser melt-solidification of a eutectic ceramic composite is demonstrated.

• Geomechanics and Engineering
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• 제8권3호
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• pp.461-476
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• 2015

Rankine's theory of earth pressure cannot be directly employed to c-${\phi}$ soils backfill with a sloping ground subjected to complex loadings. In this paper, an analytical solution for active earth pressures on retaining structures of cohesive backfill with an inclined surface subjected to surcharge, pore water pressure and seismic loadings, are derived on the basis of the lower-bound theorem of limit analysis combined with Rankine's earth pressure theory and the Mohr-Coulomb yield criterion. The generalized active earth pressure coefficients (dimensionless total active thrusts) are presented for use in comprehensive design charts which eliminate the need for tedious and cumbersome graphical diagram process. Charts are developed for rigid earth retaining structures under complex environmental loadings such as the surcharge, pore water pressure and seismic inertia force. An example is presented to illustrate the practical application for the proposed coefficient charts.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2011년도 추계학술대회
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• pp.295-296
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• 2011

The DRM+ is the newest digital radio standard for in-band environment. Although various state of the art technologies are adopted, the performance evaluation information is not sufficient. It is hard that many countries and stations considering the DRM+ as their digital radio standard check the performance of DRM+. To evaluate the performance of the DRM+ system, this paper depicts the laboratory trial results of DRM+ standard. In the laboratory trial, the rack type DRM+ test bed is built. To reflect the practical broadcasting environment, various tests are executed. Many countries and stations can efficiently use these test results, which are considering converting their analog radio broadcasting to digital broadcasting.