• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.13-19
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• 1998

Stress relaxation tests have been performed under five different tensile strain levels and five different bending strain levels. Three different theoretical models have been developed based on four-element Burger's model, viscoelastic theory and viscous-viscoelastic theory. Experimental data were used to obtain parameters of the models and to verify accuracy of the models. Among the three theoretical models developed in this study, three-integral model (Model 3) based on viscous-viscoelastic theory showed the most exact estimations of stress relaxation under both tensile and bending strains and their correlation coefficients were greater than 0.99 for all the strain levels. Model 1 showed little initial stress relaxation. Model 2 showed excessive initial relaxation and, then, no relaxation after about 20 minute of strain application. Stress retention under strain decreased as strain increased, which means increased stress relaxation as strain increases. When the strain level was less than proportional limit, the effect of strain level on stress relaxation was not clearly shown. However, this effect was increased as strain level increased when strain level was greater than proportional limit.

• 한국지형학회지
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• 제26권1호
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• pp.27-40
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• 2019

This study tries to reveal source areas of fluvial terrace deposits in Danyang and Geum River basins located in the northern and southern parts of the Sobaek Mountains, respectively, through geochemistry. The samples analyzed in this study show different grain size properties and can be grouped into the coarse, medium and fine samples. Grain size properties suggest that the coarse samples are typically fluvial deposits and geochemistry from the coarse samples is also similar to that from the bedrocks within the basins. The fine samples show geochemical properties different from the bedrocks and similar to loess deposits in Korea. However, different geochemical concentrations among the fine samples can be also recognized, indicating mixtures of loess materials with weathering products of the bedrocks. One sample among the medium samples is considered as fluvial deposit due to geochemical similarity to the bedrocks, while geochemistry from another sample among the medium samples indicates that loess materials were mixed with more abundant weathering products of the bedrocks than those in the fine samples.

• 한국전기전자재료학회논문지
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• 제37권2호
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• pp.154-163
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• 2024

The energy demand in the world is expected to exceed 740 million TJ by 2040 and our dependence on fossil fuels needs to be switched to sustainable and renewable energy sources like solar energy. Building Integrated Photovoltaic (BIPV) is one of the best approaches to extracting solar energy. There are more than 200 BIPV products in the market currently but when it comes to integrating these products into the technical aspects such as buildings' structural integrity, thermal, daylight retainment and aesthetic prospects to be considered. The share of BIPV integration potential of different building types in the world of residential, agricultural, industrial, commercial and other buildings account for 66%, 4.8%, 8.1%, 19.9%, and 1.2% accordingly. Many solar technologies developed to achieve architectural requirements, but the main problem is the trade-off between efficiency and aesthetic appeal, which is less than 10% in coloured and transparent solar modules. This paper discusses the different applications of solar photovoltaics (PV) in building architecture, technical requirements, and different module technologies. The article provides a comprehensive guide for researchers and designers working on the development of BIPV integrations.

• 산경연구논집
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• 제15권3호
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• pp.11-20
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• 2024

Purpose: This study focuses on the Chinese smartphone market to estimate product attributes influencing Chinese customers' preference for developing new smartphones through conjoint analysis. Research design, data and methodology: The online questionnaire survey is processed among Chinese potential smartphone customers. Conjoint analysis including traditional conjoint analysis (TCA) and choice-based conjoint analysis (CBCA), is used to analyze the useful data of 500. Results: Results indicate that price is the most important predictor while screen size is the least for Chinese customers' preference whether the method is TCA or CBCA. However, the importance of brand, capacity, CPU, and screen design is different. Moreover, based on each smartphone attribute level's utility, the new products with the best combinations are different compared with both methods. Finally, the predicted market shares of the top 3 products are the same with maximum utility rule model between TCA and CBCA. However, when considering with the new best combined product, they are significantly different. Conclusions: Managers should recognize the differences between TCA and CBCA and select the best method to develop new smartphones for sustainable business in the Chinese competitive market based on the important attributes of price, brand, capacity, CPU, screen design, and size.

• 한국축산식품학회지
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• 제39권1호
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• pp.54-64
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• 2019

Wet and dry aging methods were applied to improve the quality of three different beef cuts (butt, rump, and sirloin) from Hanwoo cows (quality grade 2, approximately 50-mon-old). After 28 d of wet aging (vacuum packaged; temperature, $2{\pm}1^{\circ}C$) and dry aging (air velocity, 2-7 m/s; temperature, $1{\pm}1^{\circ}C$; humidity, $85{\pm}10%$), proximate composition, cooking loss, water holding capacity, shear force, color, nucleotides content, and sensory properties were compared with a non-aged control (2 d postmortem). Both wet and dry aging significantly increased the water holding capacity of the butt cuts. Dry aging in all beef cuts induced lower cooking loss than that in wet-aged cuts. Shear force of all beef cuts was decreased after both wet and dry aging and CIE $L^*$, $a^*$, and $b^*$ color values in butt and sirloin cuts were higher in both wet and dry aging (p<0.05) groups than those in the non-aged control. Regardless of the aging method used, inosine-5'-monophosphate content among beef cuts was the same. The sensory panel scored significantly higher values in tenderness, flavor, and overall acceptability for dry-aged beef regardless of the beef cuts tested compared to non- and wet-aged cuts. In addition, dry-aged beef resulted in similar overall acceptability among the different beef cuts, whereas that in wet-aged meat was significantly different by different beef cuts. In conclusion, both wet and dry aging improved the quality of different beef cuts; however, dry aging was more suitable for improving the quality of less preferred beef cuts.

• 한국정보통신학회논문지
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• 제16권1호
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• pp.48-58
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• 2012

본 논문에서는 다중 대역 전송 시스템에서 광대역 전력 증폭기의 선형화를 위한 새로운 전치왜곡 기법을 제안한다. 특히, 한 시스템에서 동시에 다중대역/다중모드 신호를 전송함에 있어 다중대역 신호가 하나의 전력 증폭기에 의해 증폭되어 전송되는 시스템을 고려한다. 상호 대역 간 비선형 왜곡을 포함한 비선형 특성을 보상하기 위하여, 본 논문에서는 다중 전치왜곡기 블록을 갖는 새로운 전치왜곡 구조를 제안하며, 다중 전치왜곡기의 계수를 동시에 갱신하는 적응 알고리즘을 제안한다. 제안하는 다중 대역 모델을 검증하기 위하여 상용 증폭기를 사용하여 증폭기 모델을 추출하였으며, 추출된 모델을 기반으로 제안한 알고리즘을 모의실험을 통해 검증하였다. 모의실험 결과는 제안 알고리즘이 효과적으로 다중 전치왜곡기의 계수를 구할 수 있으며, 다중 대역을 효과적으로 선형화 할 수 있음을 보여준다.

• 디지털융복합연구
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• 제16권5호
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• pp.145-152
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• 2018

본 연구는 소비자들의 개인적 특성 변수인 감각적 혁신성향이 사물인터넷 제품 광고에 대한 수용자 효과에 어떠한 차이를 보이는지 알아보고자 진행되었다. 이를 위해 사물인터넷 제품 광고 3편을 선정하여 남 여 대학생 128명을 대상으로 연구를 진행하였다. 연구결과 감각적 혁신성향이 높은 소비자들이 낮은 소비자들에 비해 광고 속 제품태도와 지각된 유용성을 더욱 더 긍정적으로 인식하는 것으로 나타났다. 이러한 결과는 사물인터넷 기술이 구현된 제품 광고들에 대한 연구가 부족한 현실에서 실증연구 되었다는 점과 신기술 구현 광고의 실행과 마케팅 전략 수립에 유용한 시사점을 제공해줄 수 있을 것으로 사료된다. 더불어 향후 연구에서는 보다 다양한 소비자 혁신성 변인들을 고려한 후속 연구가 이루어질 수 있길 기대한다.

• 한국의류산업학회지
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• 제19권2호
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• pp.207-220
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• 2017

Today, the fashion industries, which are appearing in the world, can satisfy their economic needs, as well as provide and distribute their products in order to introduce sustainable methods and avoid becoming a bad influence on future generations. Recently, SPA brands have contributed to the sustainable development of society with different kinds of products, such as organic, recycled and environmental products. For this research, among different SPA brands, we chose H&M as the most representative one. Using Russian and Korean consumers as examples, we analyzed how sustainable activities affect a consumer's ethical consciousness, brand loyalty and purchase intention. The results of this study show that firstly, all sustainable activities have positive effects on the ethical consciousness of Russian and, in particular, Korean consumers. Secondly, ethical consciousness has a positive effect on brand loyalty, which, in turn, has a positive effect on purchase intention. Consequently, by adding to the existing sustainable and cultural activities, we can propose new perspectives for future research on sustainability. Due to the effect on a consumer's ethical consciousness, future research might consider ethical consciousness as the main factor. By focusing on H&M as a representative of SPA brands with Russian and Korean consumers as target audiences, we can advise global SPA brands on the direction of their sustainable activities and exporting of their products to foreign markets.

• 한국식품과학회지
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• 제20권6호
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• pp.755-761
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• 1988

식염의 1.7%, 2.2%, 2.7% 그리고 3.2%의 첨가수준에 따라 발효소세지의 숙성 및 건조중 이화학적 변화 및 미생물의 변화를 조사하였으며 또한 Stahpylococcus aureus의 접종시험을 통해서 이들의 증식관계를 조사하였다. 소금의 첨가량이 많아짐에 따라 pH는 완만하게 떨어졌으며 모든 처리구 공히 원료혼합육 5.8 수준에서 최종제품 4.8-4.6의 pH를 나타내었다. 조직은 소금의 첨가량이 높을수록 저작성과 경도가 높게 나타났으며 낮은 식염처리구에서는(1.7%, 2.2%)제품으로서의 조직을 갖지 못했다. 소금의 첨가량이 많아짐에 따라 총 세균수와 Lactobacilli수는 낮은 수준을 보였으며 아울러 완만하게 증식하는 경향을 나타내었다. 원료혼합육 g당 $10^5$ cells수준으로 접종한 St. aureus는 소금의 첨가수준에 의하여 아무런 영향을 받지 않았으며 각 처리구 마차가지로 21일 숙성기간중 $10^4$ cells/g의 수준으로 감소하였다. 그러나 Enterobacteriaceae는 소금의 첨가량이 낮아짐에 따라 그들이 생존기간이 길었다.

• Journal of the Korean Wood Science and Technology
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• 제45권3호
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• pp.360-367
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• 2017

본 연구에서는 단열성능 및 물리적 성질이 우수한 친환경 목섬유 단열재의 제조 기술을 확립하기 위하여 멜라민 요소 폼알데하이드(MUF), 페놀 폼알데하이드(PF), emulsified MDI (eMDI) 및 라텍스계 수지 등 서로 다른 접착제로 제조한 저밀도섬유판의 특성을 비교하였다. 그 결과 MUF, PF, eMDI 수지 접착제로부터는 경질(硬質) 저밀도섬유판이, 라텍스계 수지 접착제로부터는 연질(軟質)의 저밀도섬유판이 각각 제조되었다. 모든 저밀도섬유판은 일반 중밀도섬유판에 비해 현저히 낮은 열전도율을 나타냈으며, 압출 발포 폴리스티렌과 유사한 단열 성능을 나타내는 것으로 조사되었다. 한편 본 연구에서 제조한 저밀도섬유판 중 eMDI를 사용한 것은 흡수 두께/길이 팽창률 및 휨 강도 등 물리적 성질이 가장 우수하였다.