• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.204-207
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• 2007

Film bulk acoustic wave resonator (FBAR) technology has attracted a great attention as a promising technology to fabricate the next-generation RF filters mainly because the FBAR technology can be integrated with current Si processing. The RF filters are basically composed of several FBAR devices connected in parallel and in series, and their characteristics depend highly on the FBAR device characteristics. Thus, it is important to design high quality FBAR devices by device or process optimization. This kind of effort may enhance the FBAR device characteristics, eventually leading to FBAR filters of high performance. In this paper, we describe the methods to more effectively improve the resonance characteristics of the FBAR devices.

• 대한가정학회지
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• 제46권10호
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• pp.119-132
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• 2008

The aim of this study was to analyse the consumer dissatisfaction, complaint and repurchase intentions in foodservices with a particular focus on college students. For this investigation we analysed the responses of 520 college students interviewed from Daegu Gyeongbuk Province. The SPSS/WIN version 12.0 and AMOS version 6.0 were used to analyse collected data. The results were as follows : 1) Factor analysis identified 5 different consumer dissatisfaction factors: facilities, waiter/waitresses behavior, food quality, service, store operating. The level of food quality dissatisfaction was most high. Consumer complaints came in three forms: public, personally and no action. The level of personal complaint was most high. 2) AMOS analysis found that public complaints had the most influence on repurchase intentions. 3) Dissatisfaction was highest with fast food restaurants, which also received the most public complaints. 4) Dissatisfaction, complaints, and compensation strongly influenced eating-out and spending motivation of college students.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2006년도 춘계학술대회
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• pp.80-85
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• 2006

HSS (high strength steel) is widely applied to reduce the weight but improve the strength in automobiles. This research has been peformed to secure a methodology to accurately predict the springback of HSS for successful tool and process designs in sheet stamping operations. We first peformed U-draw bending test to evaluate the springback characteristic. We then evaluated forming and springback processes using the 1-row model of the finite element method. Based on the peformance measure and parameters selected, extensive analyses of the factor effects on the springback have been made using experimental design concepts. We specifically selected Taguchi's orthogonal array, $L_{18}(2^1{\times}3^7)$, and the optimal level combination of the factors have been drawn from the analysis.

• 한국전기전자재료학회논문지
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• 제14권1호
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• pp.74-83
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• 2001

In this study, the optimum structure of a magnetic thin film inductor was designed for application of DC-DC converters. The Ni$\sub$81/Fe$\sub$19/ (at%) alloy was selected as a high-frequency($\geq$MHz) magnetic thin film magnetron sputtering system. As-deposited NiFe thin films show similar magnetic properties compared to bulk NiFe alloys, indicating that they have a good film quality. The optimum design of dolenoid-type magnetic thin film inductors was performed utilizing a Maxwell computer simulator (Ansoftt HFSS V7.0 for PC) and parameters obtained from the magnetic properties of magnetic core materials selected. The high-frequency characteristics of the inductance(L) and quality factor(Q) obtained for the designed inductors through simulation agreed well with those obtained by theoretical calculations, confirming that the simulated result is realistic. The optimum structure of high-performance (Q$\geq$60, L = 1${\mu}$H, efficiency $\geq$90%), high-frequency ($\geq$5MHz), and solenoid-type magnetic thin film inductors was designed successfully.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.225-225
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• 2010

In this study, the optimum structure of a magnetic thin film inductor was designed for application of DC-DC converters. The $Ni_{81}Fe_{19}$ (at%) alloy was selected as a high-frequency($\geq$ MHz) magnetic thin film core material and deposited on various substrates (bare Si, $SiO_2$ coated Si) using a high vacuum RF magnetron sputtering system. As-deposited NiFe thin films show similar magnetic properties compared to bulk NiFe alloys, indicating that they have a good film quality. The optimum design of solenoid-type magnetic thin film inductors was performed utilizing a Maxwell computer simulator (Ansoft HFSS V7.0 for PC) and parameters obtained from the magnetic properties of magnetic core materials selected. The high-frequency characteristics of the inductance(L) and quality factor(Q) obtained for the designed inductors through simulation agreed well with those obtained by theoretical calculations, confirming that the simulated result is realistic. The optimum structure of high-performance ($Q{\geq}60$, $L\;=\;1{\mu}H$, efficiency${\geq}90%$), high-frequency (${\geq}5MHz$), and solenoid-type magnetic thin film inductors was designed successfully.

• 한국건축시공학회지
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• 제8권5호
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• pp.59-65
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• 2008

In the evaluation method of KS on the activity factor of fly ash, same amount of cement should be replaced with fly ash. Therefore, contradictory effects on concrete strength exist, i. e. strength decease due to low content of cement and strength increase of strength due to filling-pore-function of fly ash. European Committee for Standardization (CEN) specifies the method 1 to 4. adding fly ash without reducing the content of cement, for the evaluation method on activity factor of fly ash. This study investigates the applicability of the method 2 of CEN to mix design of concrete. The followings are derived ; There is a key ratio of f)y ash mixing which enhances the incremental ratio of mixing water to improve fluidity of mortar. The incremental ratio of mixing water is maximized about 11% ratio of fly ash mixing. Compressive strength most slightly increases at that ratio of fly ash mixing. Activity factor of fly ash increases as water-cement ratio becomes low and contents of fly ash becomes high. Moreover, quality of fly ash and condition of mix design affect the applicable amount of fly ash and available range of water-cement ratio. However, this method has some problems for practical purpose because activity factors of fly ash for some cases are over 1.0. Further research should be conducted to develop more useful method of evaluating activity factor of fly ash.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.168-173
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• 2022

As the function of a product is advanced and the process is refined, the yield in the fine manufacturing process becomes an important variable that determines the cost and quality of the product. Since a fine manufacturing process generally produces a product through many steps, it is difficult to find which process or equipment has a defect, and thus it is practically difficult to ensure a high yield. This paper presents the system architecture of how to build a smart manufacturing system to analyze the big data of the manufacturing plant, and the equipment factor analysis methodology to increase the yield of products in the smart manufacturing system. In order to improve the yield of the product, it is necessary to analyze the defect factor that causes the low yield among the numerous factors of the equipment, and find and manage the equipment factor that affects the defect factor. This study analyzed the key factors of abnormal equipment that affect the yield of products in the manufacturing process using the data mining technique. Eventually, a methodology for finding key factors of abnormal equipment that directly affect the yield of products in smart manufacturing systems is presented. The methodology presented in this study was applied to the actual manufacturing plant to confirm the effect of key factors of important facilities on yield.

• 디지털융복합연구
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• 제14권11호
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• pp.459-467
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• 2016

본 연구는 최근 모바일을 기반으로 급성장하고 있는 소셜 네트워크 게임에 대해 이용자들의 만족에 영향을 미치는 요인은 무엇인지 규명해보고자 진행되었다. 이를 위해 제품특성 변인인 품질요인과 소비자 특성 변인인 이용자들의 자기결정성 요인을 중심으로 남, 여 대학생 211명에게 설문조사를 실시하였다. 연구결과 첫째, 모바일 소셜 네트워크 게임에 대한 품질요인을 구성하고 있는 하위 요인 모두 이용자들의 만족에 정(+)의 영향을 미치는 것으로 확인되었다. 둘째, 모바일 소셜 네트워크 게임에 대한 자기결정성을 구성하고 있는 하위 요인 모두 이용자들의 만족에 정(+)의 영향을 미치는 것으로 확인되었다. 셋째, 모바일 소셜 네트워크 게임에 대한 품질요인과 자기결정성 요인이 이용만족에 미치는 상대적 영향력은 품질을 구성하고 있는 하위 요인들만 즉, 유희성, 사용편리성, 기능성 순으로 정(+)의 영향을 미치는 것으로 확인되었다. 본 연구결과는 그동안의 연구경향인 기술 공학적 관점과 PC기반의 온라인 게임에서의 탈피를 통해 게임관련 연구영역의 확장이라는 학술적 의의와 함께 이용자들의 편의에 맞는 양질의 게임 콘텐츠 개발을 위한 의미 있는 실무적 시사점을 제공할 수 있을 것으로 기대한다.

• 한국식품위생안전성학회지
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• 제38권4호
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• pp.236-245
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• 2023

본 연구에서는 베이커리 빵 7종의 품질안전한계기간을 분석하여 소비기한을 산출하였다. 각 제품은 50일 동안 5℃, 15℃, 25℃, 35℃에서 보관하였으며, 보관 중 수분, 미생물, 관능평가, 부패시 우점균을 분석하였다. 품질 및 안전기준은 식품공전 및 KS기준으로 설정하였다. 그 결과 5℃에 보관된 모든 제품은 50일 동안 세균수가 기준치에 적합하였으나 관능은 기준치 이하로 품질이 떨어졌다. 15℃에서 보관된 시료는 3일에서 39일까지 시료별로 품질안전한계기간의 차이가 높았다. 25℃에서는 2-20일의 품질안전한계기간 설정되었으며 하나의 시료는 유통기한과 동일하였다. 35℃에서 보관된 빵은 품질안전한계기간이 가장 짧았다. 식빵에 소비기한 설정 가이드라인을 참조로 0.87의 안전계수를 고려하면 제품별로 1.7-13.1일의 소비기한을 계산할 수 있다. 따라서 같은 유형의 제품이라도 제품의 종류에 따라 소비기한을 설정하는 것이 필요하다. 베이커리에서 유통되는 빵 제품 중 상온 제품 (1-35℃)으로 관리되는 제품은 최대 35℃의 온도 범위에서 유통 및 보관이 가능하므로 제품의 특성을 고려하여 품질유지기간을 설정하고 안전계수를 식품의 특성에 맞게 신중히 고려하는 것이 중요하다.

• Journal of Power Electronics
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• 제10권3호
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• pp.293-299
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• 2010

In this paper, a single-phase PFC (Power Factor Correction) dual boost converter based on input voltage estimation is studied for DC inverter air conditioner. It is focused on improving input power factor and power quality to satisfy the recent harmonic current regulation standards. Furthermore the input voltage estimation is introduced for price competitive products. A low cost and reasonable control system is implemented using a specified high-speed 32-bit microprocessor. Their effectiveness are verified through theoretical analysis and experiments.