• Journal of Applied Biological Chemistry
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• 제58권4호
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• pp.303-309
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• 2015

${\gamma}$-Aminobutyric acid (GABA) content in fermented plant products and their main plant materials (aerial part of Acanthopanax sessiliflorus, fruit of Crataegus pinnatifida, and whole plant of Morus alba) was determined by high-performance liquid chromatography. GABA was quantified using a reverse-phase column with a gradient elution program (water:acetonitrile =90:10 to 0:100 for 40 min). UV detection was conducted at 280 nm. GABA content was measured in fermented plant products (15.07 mg/g), aerial part of A. sessiliflorus (4.49 mg/g), fruit of C. pinnatifida (10.59 mg/g), and whole plant of M. alba (2.31 mg/g). The presence of GABA in fermented plant products, including A. sessiliflorus, C. pinnatifida, and M. alba is important in industrial application for health supplements.

• 한국가구학회지
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• 제12권1호
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• pp.131-142
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• 2001

Cultural needs of human have grown enormously. Consumer trend and individual taste have become more individualistic and diversified. Efforts to improve the quality of life have changed the concept of lift space as well as the concept of interior life supplies. Products are no longer standardized and produced in massive scale, thus a shift of value has risen. Damages done by the economical development have made consumers take interests in products that are more natural and in harmony with human beings. It is a tendency that wooden materials are becoming a preference as a specific alternative. There is a great social change with a new paradigm like this. Considering the change, we propose a new vision and activation plan on design development of wooden products through specific and practical studies by the system of educational and industrial cooperation which is an organic association system for developing human resources of educational system and producing profits of industry. From it, we can expect great effects as a competitive design of coming future.

• Smart Structures and Systems
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• 제29권6호
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• pp.767-775
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• 2022

Metal additive manufacturing (AM), also known as metal three-dimensional (3D) printing, produces 3D metal products by repeatedly adding and solidifying metal materials layer by layer. During the metal AM process, products experience repeated local melting and cooling using a laser or electron beam, resulting in product defects, such as warpage, cracks, and internal pores. Such defects adversely affect the final product. This paper proposes the in situ monitoring-based warpage prediction of metal AM products with experimental feature extraction. The temperature profile of the metal AM substrate during the process was experimentally collected. Time-domain features were extracted from the temperature profile, and their relationships to the warpage mechanism were investigated. The standard deviation showed a significant linear correlation with warpage. The findings from this study are expected to contribute to optimizing process parameters for metal AM warpage reduction.

• 한국건축시공학회지
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• 제20권1호
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• pp.19-26
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• 2020

본 연구는 소성과정에서 다량의 이산화탄소를 배출하는 포틀랜드 시멘트를 대체할 수 있는 비소성 시멘트 개발을 목표로 하였다. 이를 위해 고로슬래그 미분말과 고칼슘 플라이애시, 소석회를 사용하였다. 또한 실험 결과를 통하여 배합비율에 따른 비소성 시멘트의 특성에 대해서 파악하고, 프리캐스트 콘크리트 제품으로의 적용 가능성을 파악하고자 하였다. 실험방법은 비소성 시멘트를 제작하여 증기양생을 실시하였고 재령 3, 7, 28일의 휨강도와 압축강도를 비교하여 각 배합비의 특성을 파악하였다. 재령 28일에는 흡수율 시험과 X선 회절 분석, 내부 미세구조를 관찰하였다. 시험 결과, NSC 모르타르는 Plain 모르타르에 비해 강도는 낮지만 재령 3일에서 다수의 배합이 품질 최소기준을 만족하였다. 흡수율 시험에서는 재령 28일 기준 모든 배합이 품질 최소기준을 만족하였다. 따라서 NSC 모르타르는 목표 PC제품 생산 원료로서 적용 가능성이 높다고 판단하였다.

• 산업공학
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• 제15권3호
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• pp.286-296
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• 2002

Products which are sold with warranty, preventive maintenance actions by manufacturers and/or buyers have an impact on the total costs for both parties. In this paper, we develop the models to study the expected warranty cost for products with free repairable warranty with three types of discrete preventive maintenance. We deal with by utilizing the concept that preventive maintenance reduces the virtual age of the system. We assume that the maintenance planning horizon can be segmented into k discrete and equally sized periods. In such a scenario, numerical examples are presented.

• 한국산학기술학회논문지
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• 제2권1호
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• pp.37-42
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• 2001

본 연구는 산학협력의 일환으로 이루어 졌으며 사출성형 제품의 기능을 극대화시켜 부가가치를 높이는 방안을 제시하였다. 주된 내용은 다기능성 안경집의 설계 및 제작, 접철식 통발의 설계 및 제작 등이며 기능성 세라믹의 첨가 및 색상조화에 의한 품질 향상도 논의하였다.

• 콘크리트학회논문집
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• 제14권3호
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• pp.440-448
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• 2002

산업의 발달과 더불어 폐유리의 발생량은 점차 증가되고 있다. 콘크리트에 폐유리를 사용할 경우 알칼리 실리카 반응(ASR)에 의한 팽창으로 콘크리트에 균열이 발생하여 성능저하를 일으킬 수 있다. 본 연구에서는 폐유리의 색깔(갈색, 녹색), 입도 및 폐유리로 인해 발생되는 ASR팽창을 저감시키기 위해 산업부산물의 종류(플라이애시, 고로슬래그 미분말)와 혼입율에 따른 ASR팽창과 강도특성을 분석하였다. 또한, 포졸란 재료로서 폐유리 분말의 사용가능성을 분석하였다. 연구결과, 폐유리의 색깔에 관계없이 폐유리의 퍼시멈 입도는 2.5~l.2mm로 나타났으며, 폐유리의 입도가 2.5~l.2 mm보다 작을수록 팽창은 점차 감소하는 것으로 나타났다. 또한, 폐유리에 산업부산물의 혼입은 ASR로 인한 팽창과 강도저하를 억제시키는데 효과적이며, 0.075 mm미만의 폐유리 분말이 포졸란 재료로서 적용이 가능한 것으로 나타났다.

• 산업경영시스템학회지
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• 제37권4호
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• pp.106-115
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• 2014

Until now, because a new product (or facility) launched in market has been retired from one year of age, we can have had ASL by stub-curve method by Iowa curve. Recently, many innovative products with important role in market like display and solar-cell etc. are more durable and, what are better, they have the constant variance in ASL because of their good quality. Of course, there are some ones like smart mobile phone with relatively big dispersion in ASL. Estimating ASL of products like display and solar-cell etc., the new approach is needed. In this paper a new method applied traditional Iowa curve with accelerated reliability test (indoor/outdoor) etc. is proposed.

• 대한산업공학회지
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• 제34권1호
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• pp.32-41
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• 2008

This paper studies a joint EOQ and EPQ model in which a stationary demand can be satisfied by recycled products as well as newly purchased products. The model assumes that a fixed quantity of the used products are collected from customers and later recovered for reuse. The recovered products are regarded as perfectly new ones. We also assume that the number of orders for newly purchasing items and the number of recovery setups in a cycle can be mutually independent integers. Under these assumptions, we develop an optimization model obtaining the economic order quantity for newly procured products, the optimal lot size for the recovery process, and the sequence of the orders and the setups, simultaneously. And then a simple solution procedure to find a local optimal control parameter set is proposed. To validate the model and the solution procedure, finally, some computational experiments are presented.

• 산업경영시스템학회지
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• 제25권1호
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• pp.63-70
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• 2002

The purpose of this paper is to investigate the customer's requirements for shoe products using the survey method, to analyze customers' needs, and to supply information to make the shoe that they want. For this work, we made 38 survey items for the degree of shoe satisfaction, for foot care and shoe control, for shoe characteristics, and for shoe purchase in future. For the purchase of shoe products in future, customers in their twenties gave the highest score for shoe design among price, design, size, fashion, fitness, color, brand, so forth. However, respondents in their forties selected the degree of fitness instead of shoe design. In the question for the buying price of shoe products in future, all customers wanted shoe products between 30,000 won md 50,000 won.