• Journal of Biosystems Engineering
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• 제12권2호
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• pp.44-59
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• 1987

The objectives of this study were to analyze and develop the model systems of rice post-harvest systems from drying to processing, and to develop a bulk system among them which requires minimum system cost and less operating time. The significance of this study was the development of a computer program (PPSARR). The PPSARR makes it possible to evaluate quantitatively the performance and economics of the rice post-harvest systems. The results show that the rice post-harvest bulk system requires less time and cost such as 37-60% and 46-59% of those of the sack system, respectively. Also, the former requires less manpower than the latter. For not more than 1,800 ton of rough rice production, the bulk system which is "drying & storage by IBDS-transport-milling" is recommended, and for more than 1,800 ton, the one which is "drying & storage by IBDS - transport - storing at flat storage improved - transport - processing by RPC" is recommended.

• 한국정밀공학회지
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• 제1권2호
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• pp.33-40
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• 1984

Chatter is a relative vibration between workpiece and tool in machining of metals, and is an important limiting factor of production rate and surface quality, and also reduces the life of machine-tool itself and its tool. In this study, in order to suppress the machining chatter, the spring and the rubber damper are adopted to the tool post of a lathe. The results obtained in this experimental study are summarized as follows. 1. The spring and the damper employed in the tool post for the suppression of chatter increase the maximum chatter-free depth of cut and optimum values found for spring constant and compressive strain are 95kg/mm, 0.1954 respectively. 2. On the optimum condition resulting in this experimental study, the modified tool post increased 6 times in the maximum chatter-free depth of cut as compared with the conventional tool post.

• 산업경영시스템학회지
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• 제37권4호
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• pp.98-105
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• 2014

According to a simple survey on the current status of the assembly line design, it was found that trial and error methods on the basis of experiences have been used mainly in domestic manufacturing industries, even though there exist a lot of excellent line balancing studies. It seems that more practical researches should be carried out to develop user-oriented line balancing tools especially for small and medium-sized enterprises. This study presents a design of the line balancing tool which can support the line balancing tasks of nonspecialists. The proposed design tool is composed of three major modules: pre-process, line balancing, and post-process. In particular, pre-process and post-process are newly proposed to increase its ease of use. We applied the proposed design to a test problem and test result showed that our practical method may contribute to enhance the efficiency of production operations management.

• 전자통신동향분석
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• 제38권6호
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• pp.128-136
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• 2023

Lithium accounts for only 0.0017% of the earth crust, and it is produced in geographically limited regions such as South America, the United States, and China. Since the first half of 2017, the price of lithium has been continuously increasing, and with the rapid adoption of electric vehicles, lithium resources are expected to be depleted in the near future. In addition, economic blocs worldwide face intensifying scenarios such as competition for technological supremacy and protectionism of domestic industries. Consequently, Korea is deepening its dependence on China for core materials and is vulnerable to the influence of the United States Inflation Reduction Act. We analyze post-lithium secondary battery technologies that rely on more earth-abundant elements to replace lithium, whose production is limited to specific regions. Specifically, we focus on the technological status and issues of sodium-ion, zinc-air, and redox-flow batteries. In addition, research trends in post-lithium secondary batteries are examined. Post-lithium secondary batteries seem promising for large-capacity energy storage systems while reducing the costs of raw materials compared with existing lithium-based technologies.

• 말소리와 음성과학
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• 제5권3호
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• pp.31-38
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• 2013

This study investigated the influence of English vowel pronunciation training to English word-initial stop pronunciation. For that purpose, VOT values of English stops produced by twenty Korean English learners(five Youngnam dialect male speakers, five Youngnam dialect female speakers, five Kangwon dialect male speakers, and five Kangwon dialect female speakers) were measured using the Speech Analyzer and their post-training production was compared with their pre-training production. The result shows that post-training VOT values of voiced stops became closer to those of native English speakers in all four groups. Hence, it can be inferred that vowel pronunciation training is effective for correcting pronunciation of voiced vowels by analyzing the change of the quality of following vowels(especially low vowels) and the degree of giving stress.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2004년도 춘계학술발표대회논문집
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• pp.175-178
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• 2004

본 연구는 디지털 합성(Composition)에 있어 포스트 프로덕션에서 해야될 작업 중 분리 렌더 시스템(Separating System)을 이용한 효과적인 합성 연구에 관한 것이다. 분리 렌더는 결과적으로 제작상의 시간과 경비를 절감시켜 줄 뿐만 아니라, 제작의 퀄리티(Quality)에 직접적으로 영향을 주기 때문에 이팩츠 합성(Effects Composition)이나 특수영상 제작에 있어 없어서는 안될 중요한 부분이다. 이 분리 렌더 시스템을 이용해서 현재 진행되는 작업상의 문제를 최소화 시킬 수 있다. 또한 영상효과 제작이나 특수영상 제작중에 발생 되어지는 여러 가지 복잡한 문제점(합성)들을 이를 통해 줄여줄 뿐만 아니라, 영상합성 단계에 있어 효과적인 디지털 영상과 렌더 테이터 관리를 동시에 만들어 주기 때문이다. 이러한 방법적 연구와 결과치의 자료들을 데이터화 한다면 디지털영상 산업계에 많은 이점을 줄 것으로 기대한다.

• 방송과미디어
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• 제4권4호
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• pp.46-51
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• 1999

The introduction of broadcast digital television (DTV) was, at one time, seen as an opportunity to rationalise video formats. The reality is quite different with a rapid divergence as the united States' ATSC offers 18 formats to cover both standard definition (SD) and high definition (HD), and yet more are supported by Europe's DVB. At the same time multi-media is expanding both as an area for source material and for finished work. Post production needs to move away from single-format facilities as requirements for multi-format operation is already increasing. A 'format-independent' solution is described which allows efficient operation with any mix of input formats and able to output any format with high quality. Attention is given to retaining the speed, accuracy and immediacy which is a feature of today's professional facilities -even while handling the greater demands of HD. Another route, using 24 frames-per-second is also examined.

• 한국콘텐츠학회논문지
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• 제15권2호
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• pp.542-551
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• 2015

본 연구에서는 한국 학생들이 영어 모음들을 어떻게 인지하고 발화하는지 알아보기 위해서, 영어 전공과목을 수강하는 42명의 대학생들을 대상으로 11개의 영어 목표 모음 /i, ɪ, eɪ, ${\varepsilon}$, ${\ae}$, ${\alpha}$, ɔ, oʊ, ʊ, u, ʌ/이 들어간 영어 단어를 가지고 인지와 발화테스트를 사전과 사후 두 차례 실시하였다. 통제집단에 대해서는 영어음성학 전공수업을 통한 이론학습만을 진행하였고, 실험집단에 대해서는 이론학습과 더불어 인지와 발화 훈련을 4주간 실시하였다. 구체적인 연구의 목적은 사전테스트를 실시한 이후 4주간의 훈련과 연습을 통해 사후 인지와 발화 정확도가 얼마나 향상되었는지를 알아보는 것과 두 집단이 보인 인지와 발화의 상관관계가 사전과 사후테스트에서 어떠한지를 살펴보는 것이다. 테스트 결과 사전테스트에서는 통제와 실험 두 집단이 인지와 발화에서 강한 상관성을 보인 반면, 사후테스트에서는 두 집단 모두 인지와 발화 간에 상관성이 없는 것으로 나타났다. 이와 같은 결과는 두 집단의 사후 인지와 발화 정확도의 변화가 주된 요인인 것으로 나타났다. 통제집단은 인지에서 사후 변동 폭이 컸던 반면, 실험집단은 발화의 변동 폭이 더 컸고, 이러한 사후 인지와 발화의 변동이 상관관계에도 영향을 주었다. 이와 같은 실험 결과를 바탕으로 교육적인 함축점도 논의되었다.

• 정보교육학회논문지
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• 제20권1호
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• pp.29-38
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• 2016

본 연구는 전자책 제작 도구의 하나인 SNS형식의 '네이버 포스트'를 이용하여 전자책을 제작하는 수업활동이 학생들의 학습 태도와 학업 성취도에 미치는 영향을 알아보는 데 목적이 있다. 연구는 한 공립 초등학교 4학년 2개 학급 중, 1개 반 25명은 실험집단으로 사회과 교과에 대하여 SNS형식의 전자책 제작활동 수업을 적용하였으며, 다른 1개 반 25명은 비교집단으로 일반적인 사회과 수업을 실시한 후 그 효과를 비교분석하였다. 실험 분석 결과, SNS형식의 전자책 제작 활동 수업은 실험집단의 학업성취도 향상에는 유의미한 영향을 주지 못하였으나 학습태도 향상에 유의미한 영향을 미치는 것으로 분석되었다.

• 대한의생명과학회지
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• 제23권2호
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• pp.111-117
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• 2017

Leukocytes in blood components are involved in diverse adverse transfusion reactions such as febrile non-hemolytic transfusion reactions. Therefore, leukocyte reduction is required to reduce these adverse reactions. The objective of this study was to compare the efficiency of pre-storage filtration and post-storage filtration. Filtration time, residual leukocyte count, RBC recovery, and hemolysis were assessed after pre-storage or post-storage filtration. Compared to pre-storage filtration, filtration time was prolonged and hemolysis was dramatically increased when post-storage filtration was performed. Residual leukocytes count and RBC recovery after post-storage filtration were similar with those obtained after pre-storage filtration. These results suggest that pre-storage filtration has better efficiency than post-storage filtration. These are thought to contribute to the production of better quality of leukoreduction blood components.