• 한국통신학회논문지
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• 제34권6A호
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• pp.506-514
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• 2009

센서 네트워크를 위한 MAC 프로토콜들은 전력 소모를 최소화하기 위해 낮은 듀티 사이클(Duty Cycle)을 사용한다. 그 중에서 RMAC [4]의 경우 Pioneer(PION) 프레임을 이용하여 한 주기 내에 여러 홉을 전송한다. 본 논문에서는 HE-MAC(Hop-Extended MAC)이라는 홉 연장 프로토콜을 제안한다. HE-MAC의 데이터 전송은 기존 RMAC과는 달리 한 주기 내에 전달될 수 있는 최대 홉 수 정보가 포함된 Explorer(EXP)를 이용하여 이루어진다. EXP의 정보와 Ready-to-Receive(RTR) 상태를 이용하여 RMAC에 비해 2홉을 늘림으로써 평균 전송 지연 시간을 감소시킨다. 또한, 적응적 슬립을 통하여 불필요한 전력 소모를 최소화할 뿐만 아니라 RMAC에서 나타나는 잦은 트래픽(Traffic)으로 인한 패킷 역전 문제를 해결한다. HE-MAC의 패킷 전송 지연시간을 수학적으로 분석하였으며, ns-2를 이용한 모의실험을 통해 성능평가를 하였다. 300개의 노드가 배치된 랜덤 토폴로지에서 HE-MAC은 RMAC에 비해 전력 소모량과 평균 전승 지연 시간을 14%, 20%만큼 감소시킨다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 Proceedings of 6th International Joint Symposium on Microeletronics and Packaging
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• pp.35-43
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• 2001

Flip chip assembly on organic substrates using ACAs have received much attentions due to many advantages such as easier processing, good electrical performance, lower cost, and low temperature processing compatible with organic substrates. ACAs are generally composed of epoxy polymer resin and small amount of conductive fillers (less than 10 wt.%). As a result, ACAs have almost the same CTE values as an epoxy material itself which are higher than conventional underfill materials which contains lots of fillers. Therefore, it is necessary to lower the CTE value of ACAs to obtain more reliable flip chip assembly on organic substrates using ACAs. To modify the ACA composite materials with some amount of conductive fillers, non-conductive fillers were incorporated into ACAs. In this paper, we investigated the effect of fillers on the thermo-mechanical properties of modified ACA composite materials and the reliability of flip chip assembly on organic substrates using modified ACA composite materials. Contact resistance changes were measured during reliability tests such as thermal cycling, high humidity and temperature, and high temperature at dry condition. It was observed that reliability results were significantly affected by CTEs of ACA materials especially at the thermal cycling test. Results showed that flip chip assembly using modified ACA composites with lower CTEs and higher modulus by loading non-conducting fillers exhibited better contact resistance behavior than conventional ACAs without non-conducting fillers. Microwave model and high-frequency measurement of the ACF flip-chip interconnection was investigated using a microwave network analysis. ACF flip chip interconnection has only below 0.1nH, and very stable up to 13 GHz. Over the 13 GHz, there was significant loss because of epoxy capacitance of ACF. However, the addition of $SiO_2filler$ to the ACF lowered the dielectric constant of the ACF materials resulting in an increase of resonance frequency up to 15 GHz. Our results indicate that the electrical performance of ACF combined with electroless Wi/Au bump interconnection is comparable to that of solder joint.

• 한국실내디자인학회논문집
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• 제26권6호
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• pp.97-105
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• 2017

Korea is promoted STEAM education since 2011. Furthermore, in high school education, based on the in-depth elective course's teaching and learning contents of science. The STEAM program can improve students' competence because it encourages to self-directed learning through the vocational project performance. Therefore, in this study, we researched a design education program for the experience of fusion and complex design based on STEAM education concept. We developed an education program to design insulation wall systems using up-cycling concepts to increase energy efficiency. As a result, the characteristics of the fusion education and the theoretical study about the learner-centered education curriculum, the analysis of the high school curriculum, the STEAM elements, The program was revised and supplemented through consultation with STEAM experts. In addition, the developed program was applied to high school students, and each step were analyzed based on the educational method theory. The following results were obtained. First, this study presented a program to cope with the needs of high school intensive education. Second, it provided learning motivation by combining flipped-learning as a way to train STEAM education contents. Third, it is required to develop differentiated and continuous program development and data sharing Fourth, in order to operate and promote the future environment design STEAM school, it is necessary to expand educational programs for high school students in the region through linkage with various universities.

• Korean Chemical Engineering Research
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• 제51권5호
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• pp.540-544
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• 2013

고분자전해질연료전지(PEMFC)는 시동/정지과정에서 성능과 수명이 감소한다. 본 연구에서는 캐소드가스로 산소를 사용하는 데드엔드 형 PEMFC의 시동/정지 과정의 영향을 분극곡선, 임피던스(EIS), SEM과 TEM을 사용해 연구하였다. 시동/정지 과정에서 PEMFC 성능감소를 막기 위해서는 더미 로드를 사용해야 함을 보였다. 시동/정지 반복과정 중 50% 상대습도(RH)에서 캐소드 카본지지체의 부식에 의한 열화가 100% RH보다 심했다. 데드엔드 형 PEMFC의 정지과정에서 PEMFC에 물을 공급해줌으로써 50% RH에서 열화속도를 감소시켰다.

• 복식문화연구
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• 제26권6호
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• pp.899-918
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• 2018

Upcycling is the process of repurposing abandoned resources or useless products into products of better quality or higher environmental value. Upcycling products are evaluated to be sustainable because they demonstrate environmental values. However, domestic upcycling companies are operating on a small scale with a slow growth rate. This study aims to examine the value and risk factors of upcycling products from previous literature and clarify the effect of these ambivalent characteristics on purchase intention. This provides direction regarding factors upcycling companies should focus on. The data were collected via an online experiment with women in their 20s and 30s residing in South Korea, nationwide. The data were statistically analyzed using SPSS 21.0 and AMOS 18.0. Analysis of this data suggests that environmental, design, and self-expression value positively affect purchase intention. This extends previous upcycling literature by identifying design and self-expression value as important antecedents of purchase intention. However, in contrast to previous literature, no significant effect of performance or diversity risk was found. These results indicate that ethical attitude has a moderating effect on the relationship between environmental value and purchase intention. This study confirms that consumers intend to purchase upcycling products when they possess not only environmental value but also design and self-expression value.

• 대한한의학방제학회지
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• 제30권4호
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• pp.281-291
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• 2022

Objectives : In this study, acute oral toxicity test of pomace Schisandra chinensis extracts was conducted in order to up-cycling to a high value-added industry using by-products discarded in the production process of Schisandra chinensis products and active ingredients such as dibenzocyclooctadiene lignans in Schisandra chinensis. Methods : Pomace Schisandra chinensis extracts were orally administered to SD-rats(female, n=3) without a control group according to the 'OECD guidelines'. After, mortality and clinical signs were observed, and the deceased animals were subjected to an autopsy. In addition, acute oral toxicity test was sequentially performed in step I (300 mg/kg), step II(300 mg/kg), step III(2,000 mg/kg), and step IV(2,000 mg/kg) according to the mortality. Results : There were no abnormalities caused by pomace Schisandra chinensis extracts in step I and step II. However, one animal each died in step III and step IV. In addition, clinical signs(salivation, decrease in food intake, prone position, decrease of locomotor activity, loss of locomotor activity, convulsion, hypothermia, lacrimation, staining around mouth, soiled perineal region, reddish urine, chromaturia, decrease of fecal volume, lying on side, blackish stool, no stool, compound-colored stool, refusal to feed, excitement, hypersensitivity, rigidity, dorsal position, etc.) were observed. But, no clinical signs were observed from 5th day, and experiment animals recovered completely. Conclusions : As a result of this study, pomace Schisandra chinensis extracts may exhibit acute toxicity at concentrations of 2,000 to 5,000 mg/kg, and the GHS classification was designated as 'Category 5'.

• 한국의상디자인학회지
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• 제25권2호
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• pp.1-16
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• 2023

Due to the current seriousness of environmental pollution and the eco-friendly movement of the fashion industry, research on sustainable fashion design is being actively conducted. In this study, consumer perception of upcycling products, are divided into image, function, and meaning; and image is further divided into shape, color, and material. It was redefined as pattern, and image recognition was evaluated among men and women in their 20s and 30s, and men and women in their 40s and 50s used as subjects. First, factors that determine each image were extracted based on qualitative analysis of the precedent cases of upcycling bags, and quantitative analysis of the subjects was induced through a questionnaire. As a result of the analysis of evaluation items related to image association, the average frequency analysis of all subjects for each stimuli and the cognitive variance of the frequency analysis by generation by gender were found to be similar. However, awareness of some stimuli by generation showed a significant difference. Overall, in the three stimuli with high overall preference, common features, such as the basic box-shaped symmetrical structure, the monochromatic color of the Munsell system, solid and practical texture, and appropriate use of patterns were identified. In addition, it was confirmed that there was a difference with factors such as femininity, simplicity, touch, and splendor in the measurement factors. In conclusion, it is considered that the main significance of this study is that it excluded the recognition and meaning of upcycling products and explored the original design and image elements of products. Therefore, it is expected that this study will be used as a basic data for responding to the gender image of each generation as an alternative method of sustainable fashion design, and it will be an opportunity to expand the scope of the study to a detailed study beyond the biased topic.

• 대한한의학방제학회지
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• 제31권4호
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• pp.327-339
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• 2023

Objectives : This study conducted a repeated dose 90-day oral toxicity test in order to up-cycling Schisandra fruit extract powder(SFEP) using discarded Schisandra chinensis by-products and evaluated the NOAEL of SFEP. Methods : SD-rats were orally administered SFEP at concentrations of 0, 62.5, 125, and 250 mg/kg once daily for 90 days. Body weights and clinical signs were observed during the administration period. After completion of the experiment, the experimental animals were autopsied to observe necropsy findings and organ weights changes, and hematological parameters and blood chemistry values were measured. Results : During the SFEP administration period, clinical signs such as salivation, wounds, and erosion were sporadically observed in 1 to 2 animals. In the SFEP 250 mg/kg administered group, weights of the liver and thyroid gland significantly increased compared to the control group, but no significant changes were observed in organ weights according to body weights. As a result of measuring hematological parameters and blood chemistry values, a decrease in RDW, T-BIL, and TBA, and an increase in TP, ALB, and Ca were observed due to SFEP administration. However, these changes following SFEP administration were accidental and not dose-dependent. Additionally, no correlation was found between gender and other parameters. Conclusions : Therefore, the NOAEL of SFEP was confirmed to be 250 mg/kg.

• 패션비즈니스
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• 제28권2호
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• pp.125-138
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• 2024

The purpose of this study is to develop and implement a step-by-step upcycling fashion education program that can be utilized within the local community. This program aims to provide basic data by analyzing the current state of community-based upcycling projects and upcycling center programs. To achieve this, the study first examined the meaning and value of upcycling in fashion through literature research and explored upcycling projects and programs in connection with local communities. Subsequently, an upcycling fashion education program platform was developed and applied using the design thinking process. The program involved students from nine high schools in Gwangju Metropolitan City. Depending on the school's circumstances, the time and difficulty level of the upcycling education program were adjusted accordingly. A unique eco-bag making kit, using jeans developed in this study, was employed. Following the completion of the program, a satisfaction survey was conducted among 167 participating students from the high school community class. The findings indicated that the majority of students experienced an increased appreciation, attraction, and interest in upcycling products. They also demonstrated an understanding of the environmental impact of upcycling products and the distinction between upcycling and recycling. It is believed that the educational program developed in this study can promote ethical fashion and foster a sense of value-based consumption. This program can be customized and flexibly adapted to different educational levels and institutional characteristics, making it accessible to a wide range of learners.

• 마이크로전자및패키징학회지
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• 제15권2호
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• pp.37-45
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• 2008

본 논문에서는 유기 기판 위에 $100{\mu}m$ 피치를 갖는 플립칩 구조인 Cu(60 um)/SnAg(20 um) 더블 범프 플립칩 어셈블리를 구현하여 이의 리플로우, 고온 유지 신뢰성, 열주기 신뢰성, Electromigration 신뢰성을 평가하였다. 먼저, 리플로우의 경우 횟수와 온도에 상관없이 범프 접속 저항의 변화는 거의 나타나지 않음을 알 수 있었다. 125도 고온 유지 시험에서는 2000시간까지 접속 저항 변화가 관찰되지 않았던 반면, 150도에서는 Kirkendall void의 형성으로 인한 접속 저항의 증가가 관찰되었다 또한 Electromigration 시험에서는 600시간까지 불량이 발생하지 않았는데 이는 Al금속 배선에서 유발되는 높은 전류 밀도가 Cu 칼럼의 높은 두께로 인해 솔더 영역에서는 낮아지기 때문으로 해석되었다. 열주기 시험의 경우, 400 cycle 이후부터 접속 저항의 증가가 발견되었으며, 이는 열주기 시험 동안 실리콘 칩과 Cu 칼럼 사이에 작용하는 압축 변형에 의해 그 사이에 있는 Al 및 Ti 층이 바깥쪽으로 밀려나감으로 인해 발생하는 것으로 확인되었다.