• 산업기술연구
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• 제37권1호
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• pp.32-36
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• 2017

In this study, as part of a research on the development of economical high-performance concrete with high strength and high quality, the physical properties of high-performance concrete were analyzed by substituting a certain amount of low-cost domestic silica fume exempted from the re-importation type distribution structure of the domestic production and the existing high-priced silica fume distribution structure. Performing tests to identify the physical properties of the fresh and hardened concrete and durability analogy of the concrete which use low-cost domestic silica fume and imported silica fume, the chloride ion penetration resistance test result showed that the strength difference between the low-cost silica fume and the imported silica fume is not big but the strength of the low-cost silica fume was measured higher than the imported silica fume. The chloride ion penetration resistance of all variables was measured as "very low". Since the low-cost domestic silica fume can be used as a high-performance admixture of concrete, the results suggest that it is possible to produce a more economical high-performance concrete.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2310-2312
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• 2004

In Korea Electric Power Corporation (or KEPCO), several Demand-Side Management (or DSM) program have been carried out to effectively meet electric power demand at least costs by modifying customers electricity use patterns. As one of them, KEPCO applies low-priced night thermal-storage power service for heat appliances to facilitate efficient use of power facilities by shifting relatively high daytime demands to night hours to build loads during the off-peak periods. In the market of heat-storage type water-heater, electric water-heater has been mostly used, but it has low energy efficiency and needs high capacity electric equipments. So in order to replace these electric water heaters, 15 HP air-source heat pump water heater is developed in Korea Electric Research Institute (or KEPRI). This paper shows that measurement system for performance testing of heat pump water heater is established and heating capacity and performance is analyzed and measured for out-door environmental change.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권12호
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• pp.628-632
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• 2006

This paper deals with the electric and thermal characteristics of the composite busbar composed of aluminum and copper. When AC current is flowing in Cu busbar used widely in conservative equipments like power cable, transformer, and switchgear & controlgear most current is concentrated on the surface of the busbar by the skin effect. Therefore, if the Cu region in the busbar having low current density is replaced with aluminum, we can largely reduce the product cost and weight of the busbar. To conform the performance of the composite busbar, we designed and fabricated a test Al/Cu composite busbar. Maximun temperature rise of the busbar was $35^{\circ}C$ when 1600 Arms of AC current was applied to the test composite busbar($120mm{\times}10mm$). Based on test results, we can expect to make the low-priced and light power equipments using the Al/Cu composite busbar.

• Mass Spectrometry Letters
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• 제11권4호
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• pp.95-102
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• 2020

In this study, we provide full descriptions of how to make a low-cost and completely open-source laboratory-made air sampler that will be used for sample adsorption for thermal desorption-gas chromatography mass spectrometry (TD-GC/MS) analysis. It is well known that harmful gases cause bad effects on human bodies, so it is necessary to identify the types and amounts of gases in industrial sites. One of the most commonly used methods for gas sampling is to utilize a sorbent tube using an air sampler. Commercially available air samplers are expensive, typically priced between $1,000 and $2,000, and their design often cannot be modified to fit the experiment. To address these shortcomings, we have developed a do-it-yourself (DIY) air sampler that is not only cheap enough, but also completely open-source. Furthermore, the performance of the fabricated air sampler was validated in conjunction with TD-GC/MS for the analysis of volatile compounds.

• 한국항행학회논문지
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• 제27권6호
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• pp.884-887
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• 2023

Recently, research has been actively conducted to overcome the limitations of high-priced single sensors and reduce costs through the convergence of low-cost multi-variable sensors. This paper estimates state variables through asynchronous Kalman filters constructed using CVXPY and uses Cvxpylayers to compare and learn state variables estimated from CVXPY with true value data to estimate filter parameters of low-cost sensors fusion.

• 펄프종이기술
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• 제38권4호
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• pp.1-9
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• 2006

Increasing the filler content of sheet provides an opportunity for saving production cost through fiber replacement with relatively low-priced filler. But increasing the filler content tends to decrease the strength of paper and filler retention. To overcome these problems, preflocculation technology of fillers has been suggested. To evaluate the effect cationic polymers on the size and size distribution of preflocculated GCC and their shear stability, cationic PAM and cationic starch were used. Results showed that cationic PAM formed large prefloc at low dosage. It was required to add 15 times as high as cationic starch to cationic PAM to obtain the same size prefloc. But preflocs formed with cationic starch was superior in shear stability to those formed with cationic PAM. With the increase of shear rate the size of preflocs decreased. Greater amount of small preflocs or un-flocculated fillers was observed when the dosage of polymers was low and this ended up low ash retention in handsheets.

• 자원리싸이클링
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• 제16권2호
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• pp.48-55
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• 2007

석탄화력발전소에서 부산물로 발생하는 비산재를 이용하여 저밀도 폴리에틸렌 열분해용 저가 크래킹 촉매를 합성하였다. 석탄비산재에 포함되어 있는 실리카와 알루미나를 NaOH와의 융합을 통해 용출시키고 이를 공침시킴으로써 비정질 실리카알루미나 촉매로 합성하였다. NaOH/석탄비산재 중량비와 활성화 시간 등의 합성조건이 촉매 합성에 미치는 영향을 살펴보기 위하여 열중량분석기를 사용하여 저밀도 폴리에틸렌 촉매 열분해를 수행하였다. 열분해 온도 변화와 열분해 생성물의 비점분포를 분석하여 합성 촉매의 성능을 평가하였으며 합성된 촉매의 물리적 특성과 촉매 활성간의 관계를 고찰하였다. NaOH/석탄비산재의 중량비가 1.2이고 활성화 시간이 8시간일 때 합성된 촉매가 가장 우수한 성능을 나타내었다. 최적 조건에서 합성된 촉매는 상용촉매와 유사한 활성을 나타내어 우수한 효과를 나타내었으며 폐플라스틱 재활용에 효과적으로 사용할 수 있으리라 예측된다.

• 문화기술의 융합
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• 제6권3호
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• pp.33-43
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• 2020

본 연구의 목적은 호텔이용고객을 대상으로 숙박비 지불수준을 조사하고, 지불수준(저가, 중가, 고가)에 따른 호텔선택요인의 차이를 분석하여 호텔 가격대별 고객유치를 위한 마케팅 방안을 제시하는데 있다. 연구목적을 달성하기 위해 2020년 2월 1일부터 2020년 4월 30일까지 호텔의 이용고객을 대상으로 설문조사를 실시했다. 총 350부의 설문지를 배포하여, 분석에 부적절한 45부를 제거하고, 최종적으로 305부의 설문지가 분석에 활용되었다. 분석결과, 집단 간에 가장 큰 차이를 보인 항목은 기본요인 중에서는 호텔크기, 조식메뉴, 레스토랑, 부대시설로 나타났다. 객실요인에서는 어메니티 부분이, 부대요인에서는 외부 관광 프로그램이 집단 간 차이가 있는 것으로 분석되었다. 핵심요인은 집단 간 차이를 보인 항목은 없었으나, 가장 중요한 요인으로 분석되었다. 이러한 내용을 바탕으로 마케팅 방안을 제안하면 다음과 같다. 저가 호텔은 고졸 학력의 20대 여성을 타겟으로, 저가형 가격정책과 프로모션을 하는 것이 효율적일 것이다. 중가 호텔은 대졸 학력의 40대 남성을 타겟으로, 셔틀버스 운영, 객실가격 프로모션, 직원서비스교육 등에 힘써야한다. 고가호텔의 경우는 20대 고졸 여성을 타겟으로, 전반적인 서비스 강화, 직원교육, 바이럴 마케팅 등이 중요한 것으로 분석되었다.

• 한국안광학회지
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• 제12권1호
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• pp.35-40
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• 2007

우리나라 대부분의 안경 제조업체는 10인 이하의 영세 소규모 업체로 구성되어 있어 규모면에서 이태리, 중국 등 경쟁국에 비해 매우 열악한 수준에 놓여 있다. 이로 인해 국내 안경산업은 선진국의 고가제품과 중국등 동남아 지역의 저가 제품 사이에서 경쟁력을 확보하지 못하는 어려운 상황에 직면하게 되었다. 이러한 점들을 고려하여 볼 때 국내 안경산업의 활성화를 위해 가장 시급한 문제는 안경 제조업체의 구조조정으로 볼 수 있으며 디자인 개발능력 향상, 신소재 및 기술개발, 자체브랜드 개발 및 홍보강화, 기능성 안경 등 신제품 개발, 시제품(샘플) 제작기간 단축, 경영지원, 특구지정을 통한 경쟁력 확보 등도 우리나라 안경산업의 중요한 활성화방안으로 지적되고 있다.

• 한국의상디자인학회지
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• 제9권1호
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• pp.189-201
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• 2007

Contemporary young people reveal their own personal values through the fashion that creates visual looks. Since 2000s began, young generations who are self-centered, value their own personality and constantly seek for changes form the main axis of fashion. In particular, the lower half of the body that has begun to be exposed outward has become the region that they want to expose as more ideal region than the upper half of the body. Further, young generations always have interest in fashion, and female college students in their early 20s are regarded as the group that values the aspects of pleasure that involve clothes and tends to seek sensibility when purchasing clothes. With this background, this study aims to examine how the styles that apply to modern fashion and recent vogues are evaluated with a focus on skinny jean from jean pants styles preferred by female college students. Materials regarding theoretical background and photos were collected from fashion related magazines at home and abroad and from the Internet websites. Questionnaires were surveyed for 160 female college students aged 20 or 25 who live in Seoul, and the results show as follows: Many female college students enjoy skinny jean and follow the fashion. However there are consumers who cling to their own styles even in the fashion of skinny jen. Ironically, some consumers wear it although they consider it as an item that does not fit Koreans: they tend to consider perspectives from others rather than their own preferences. For example, they wear it in order to show it to their boy friends or because they want themselves to look slim. In addition consumers seem to use Dongdaemun Shopping Mall or Internet shopping malls that provide various and low-priced items rather than to use high-priced famous products. It is considered that this result is shown as above because the scope of the study was restricted to female college students in their 20s. Accordingly, it is suggested that further studies should extend their subjects to wider range of ages.