• Elastomers and Composites
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• 제40권2호
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• pp.119-127
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• 2005

Material characteristics and lifetime evaluation are very important in design procedure to assure the safety and reliability of the rubber components. In this paper, the material test and accelerated heat aging test were carried out to predict the useful life of NBR and EPDM rubber mount for a compression motor which is used in a refrigerator. In order to investigate the effects of heat-aging on the material properties, crosslink density, modulus at 100% strain, stress-strain curves were obtained from uniaxial and equi-biaxial tensile tests. The change of compression set were used for assessment of the useful life and the time to threshold value were plotted against the reciprocal of absolute temperature to give the Arrhenius plot. The useful life at variable temperatures are obtained in the Arrhenius relationship.

• The Journal of Korean Academy of Prosthodontics
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• 제51권4호
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• pp.353-360
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• 2013

Cleft lip and palate is congenital deformity in oral and maxillofacial area. Normal soft palate has velopharyngeal closure action by connecting oral cavity and nasal cavity at rest and moving upward at swallowing and specific pronunciation. Cleft palate patients with velopharyngeal insufficiency have difficulty in mastication, swallowing and pronunciation because velopharyngeal closure is incomplete. At this time, a prosthetic device used to cover palate defects is called a palatal obturator. A palatal obturator separates oral cavity and nasal cavity and recovers pronunciation, mastication, swallowing and esthetic function. The purpose of this case study is to report the results because it reaches a satisfactory result in functional and esthetic aspects through functional impression procedures using modeling compound and tissue conditioner for restoration of a cleft palate patient with velopharyngeal insufficiency.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제38권3호
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• pp.28-34
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• 2001

To improve the skirt characteristic of the high-temperature superconducting filter, we proposed a structure of cascading two independent hairpin-comb filters with an identical frequency response. Resonators of the cascaded filter are arranged in the shape of a diamond so that it minimizes the cross coupling between the resonators. This structure can be used effectively to improve the skirt characteristic of the filter in limited area of a circular wafer. The simulated skirt characteristic of the 18 pole cascaded filter is more than 40dB/MHz attenuation below and above the passband.

• Knowledge Management Research
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• 제21권1호
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• pp.61-78
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• 2020

Recently, in the global financial transaction field, global transactions using computer systems and server hubs between foreign exchanges beyond the one-dimensional offline transactions and two-dimensional online transactions have been actively conducted. In the previous research by Lee Hyung-wook and Lee Min-jae (2018), as the globalization has accelerated following the development of digital technology and the expansion of ubiquitous communication network, the role of companies, the attribute of economic value creation and economic structure are being reorganized. It is said that O2O (Online to Offline) transactions are increasing due to the development. As a result, a new financial transaction paradigm is emerging that solves the inconveniences of existing financial services and enhances speed and convenience. Considering the global network trend and the rapidly developing and evolving digital bank environment, the necessity of utilizing the business platform model is emerging. However, despite this necessity, there are very limited cases in which such an attempt has been applied in practice. Accordingly, this study seeks to explore the business platform of the new financial transaction system. Specifically, the case study systematically examines the actual implementation of a unique network connection model with Koscom's global investment bank, which is currently in charge of the domestic financial transaction system, and improves ICT innovation performance and process through this. I would like to suggest a solution. In particular, this study analyzed a variety of business model construction and use cases by pursuing a platform connection with digital banks, which has recently been increasingly in demand. Therefore, this study intends to pursue the original and long-term profitability of the company by utilizing ICT innovation and platform business model, and also analyzes the convenience and excellence of trading for institutional and individual investors using the platform of digital bank. The implications of this study are significant in that it explores and explores the actual cases of ICT innovation and additional digital bank platform-connected business models based on this, and suggests a unique and preemptive business strategy of the company in the future.

• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.68-68
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• 2003

최근의 전자부품은 고밀도 고집적화 됨에 따라 여러 가지 문제점들이 발생되고 있다. 그 중 부품이 실장되는 부분에 사용되는 솔더나 전기적 회로를 구성하는 패턴간에 금속 이온 마이그레이션(Metallic Ion Migration)이 발생하여 전기적 단락(Short)를 유발함으로써 전자제품의 치명적 고장을 유발한다. 본 연구는 이온 마이그레이션 현상을 물방울시험(Water Drop Test)을 통하여 재현함으로써 발생 메카니즘을 확인하여 발생원인을 직접적으로 관찰하고, 각 종 패턴의 거리 및 전압에 따른 발생속도의 차이를 조사하기 위하여 수행되었다. 이러한 실험을 위하여 콤 패턴(Comb Pattern)의 FR-4 재질 인쇄회로기판(PCB : Printed Circuit Board)을 사용하였으며, 사용된 전극재질로는 Cu, SnPb, Au를 사용하였고, 패턴간 거리는 0.5, 1.0, 2.0mm의 3가지 종류로 구분하였다. 또한 패턴간에 인간 된 전압은 6.5V, 15V를 인가한 후 마이그레이션이 발생되는 시간을 측정하였다. 이러한 실험으로부터 다음과 같은 결론을 얻었다. (1) 6.5V의 인가전압에서는 Cu 패턴이 대체적으로 가장 빠르게 마이그레이션이 발생하였으며, 다음으로 Au가 발생하였고, Cu와 SnPb의 발생시간은 대체적으로 근사한 값을 나타내었다. 이것은 비슷한 평형전위를 갖는 재료는 마이그레이션 발생시간이 유사하게 나타나며, 높은 (+)전위를 갖을수록 발생시간이 지연됨을 알 수 있다. (2) 15V를 인가하였을 때 패턴간격이 0.5mm인 경우 Cu, Au, SnPb의 순으로 나타났으며, 1.0mm는 SnPb, Cu, Au, 2.0mm인 경우는 SnPb, Au, Cu의 순으로 마이그레이션이 발생하였다. 인가전압이 높은 경우 초기 발생에는 큰 차이가 없지만 수지상이 발생 후 성장하는데 많은 영향을 미치는 것으로 보인다. 이것은 초기 수지상의 형성에 큰 영향을 미치는 것은 재료의 평형전위에 의한 값이 좌우하지만, 수지상이 일정길이 이상 형성된 이후에는 성장속도가 평형전위에 따른 값과는 다소 다르게 나타남을 알 수 있다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• 제43권5호
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• pp.62-71
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• 2006

Development of an artificial reverberation algorithm with low memory requirements has been an issue of importance in applications such as mobile multimedia devices. One possible solution to this problem is to embed a time-varying all-pass filter to the feedback loop of the comb filter. In this paper, theoretical and perceptual analyses of reverberators embedding time-varying all-pass filters are presented. The analyses are to iud a perceptually acceptable degree of phase variation by the all-pass filter. Based on the analyses, we propose a new methodology of designing reverberators embedding time-varying all-pass filters. Through the subjective tests, we showed that, even with smaller memory, the proposed method is capable of providing perceptually comparable sound quality to the conventional methods involving time-invariant parameters.

• Journal of the Korean Institute of Telematics and Electronics S
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• 제35S권9호
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• pp.78-85
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• 1998

In this paper we propose a VLSI implementation technique for camcorder's digital zooming system. The proposed VLSI includes the system clock(CLK), vertical drive(VD), horizontal drive(HD),blank(BLK), and field(FLD) signals as inputs, and produces magnified image as an output, with 256 different magnification ratios. In general, the above mentioned input signals are provided by the CCD driving IC in most camcorders. As a result, the proposed digital zooming VLSI can magnify a part of the input image by up to 256 times, where the magnification ratio can be chosen among 256 different steps. In the application point of view, the proposed VLSI can be used in any digital camcorder for realizing near continuous step digital zooming without any additional circuitry, such as micom or a general purpose digital signal processor.

• Journal of the Korean Geotechnical Society
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• 제19권5호
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• pp.301-310
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• 2003

In order to design accurately sand compaction pile (SCP) method with low replacement area ratio, it is important to understand the mechanical interaction between sand piles and clays and its mechanism during consolidation process of the composition ground. In this paper, a series of numerical analyses on composition ground improved by SCP with low replacement area ratio were carried out, in order to investigate the mechanical interaction between sand piles and clays. The applicability of numerical analyses, in which an elasto-viscoplastic consolidation finite element method was applied, could be confirmed comparing with results of a series of model tests on consolidation behaviors of composition ground improved by SCP. And, through the results of the numerical analyses, each mechanical behavior of sand piles and clays in the composition ground during consolidation was elucidated, together with stress sharing mechanism between sand piles and clays.

• Journal of the Korea Fashion and Costume Design Association
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• 제7권1호
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• pp.55-63
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• 2005

The outcome of modem sports events are reliant on not only the athletic ability and technology of individual players but their sportswear proterties. State-of-the-Hitech sportswear has started to be introduced in the 1950s, and in addition to the athletic capability of players, sportswear is one of the primary factors to affect the results of sports games, as a wide variety of Hi-Tech functional materials have come out since the 1990s. The purpose of this study was to development into the concept of active sportswear, to sort out hitech functional product lines in this field, to look into sports stars and Hi-Tech functional sports brands, and finally to identify the major characteristics of recent active sportswear. The result of this study were as follows: 1. There were largely four characteristics in recent functional sportswear materials: fast-drying cooling, minimized resistance, ultralight comfortableness, and water vapor permeable/waterproof function. 2. Besides the athletic capability and technology of players, Hi-Tech functional products are one of the major factors to determine the outcome of modem sports events. Functional synthetic fiber is preferred, instead of cotton, since the former is easier to manage and retains humidity better. 3. The major features of recent trend in active sportswear products are, functional, diversity and value. That is, those products are functional, since they are easy to manage and retain proper humidity, and they are for multipurpose, since they are fashionable and practical at the same time. And they are valuable, being expensive but appropriate for the movement of the body and having a high quality.

• Journal of Animal Environmental Science
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• 제2권2호
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• pp.147-154
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• 1996

In an attempt to recycle as feed or fertilizer, broiler litter containing rice hull was manually composted under the control of peak temperature of piles(uncontrolled or controlled below $70^{\circ}C$ or below $60^{\circ}C$) in each of three $1.0\;{\times}\;1.0\;{\times}\;1.2m$ dimensional facilities. Changes of nutritional and microbiological parameters were evaluated throughout the 8 weeks of processing period. The initial content of crude protein(29.6%) decreased to 17.8% after 8 weeks of composting. The rapid nitrogen(N) loss observed in the early phase was attributed mainly to non-protein-N(NPN) loss. The initial content of ash(19.1%) increased to $26{\sim}29%$ after 8 weeks. For toxic heavy metals, Cr, Pb, and Hg contents of final composts were far less than the maximum tolerance levels allowed in food or compost. Bacterial growth was rather depressed until the second week, increased thereafter, and reached to peak($10^{12}cfu$ level) at the 4th week of composting. With composting, actinomycetes were active at the level of $10^7\;to\;10^9$. Fungi were active during the first to third week of composting. In general, control of pile temperature below $70^{\circ}C$ did not remarkably alter the nutritional and microbiological parameters of broiler litter compost, compared to that of pile temperature below $60^{\circ}C$. Further researches on prevention from the rapid loss of NPN in the early phase of composting are required for more effective recycling of broiler litter.