• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.6
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• pp.606-614
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• 1991

A robust direct adaptive controller with respect to additive and multiplicative unmodeled dynamics is designed. A new term, proportional to the product of the bounded tracking error and normalizing signal, is added to the conventional control input for improvement of robustness and performances of an adaptive system. It is shown by the mathematical analysis and simulation results that the stability of the closed loop system is guaranteed and the performance of the system is improved.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.285-288
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• 2000

In this paper, we propose a Reed-Solomon decoder for the DVD Reed-Solomon(RS) product code based on new efficient euclid cell architecture suitable for Modified Euclid Algorithm. We synthesized the RS decoder using Hyundai 0.65um CMOS standard cell library and compared the performance of the decoder with one of the conventional architectures. The result shows that the proposed euclid cell use about 32% less symbol time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.137-145
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• 2020

Various elements of Fabrication (FAB), mass production of existing products, new product development and process improvement evaluation might increase the complexity of production process when products are produced at the same time. As a result, complex production operation makes it difficult to predict production capacity of facilities. In this environment, production forecasting is the basic information used for production plan, preventive maintenance, yield management, and new product development. In this paper, we tried to develop a multiple linear regression analysis model in order to improve the existing production capacity forecasting method, which is to estimate production capacity by using a simple trend analysis during short time periods. Specifically, we defined overall equipment effectiveness of facility as a performance measure to represent production capacity. Then, we considered the production capacities of interrelated facilities in the FAB production process during past several weeks as independent regression variables in order to reflect the impact of facility maintenance cycles and production sequences. By applying variable selection methods and selecting only some significant variables, we developed a multiple linear regression forecasting model. Through a numerical experiment, we showed the superiority of the proposed method by obtaining the mean residual error of 3.98%, and improving the previous one by 7.9%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.3068-3085
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• 2021

The economics of big data knowledge, especially cloud computing and statistical data of consumer preferences, has attracted increasing academic and industry practitioners' attention. Firms nowadays require purchasing not only external private patent knowledge from other firms, but also proprietary big data knowledge to support their new product development. Extant research investigates pricing strategies of external private patent knowledge and proprietary big data knowledge separately. Yet, a comprehensive investigation of pricing strategies of these two types of knowledge is in pressing need. This research constructs an overarching pricing model of external private patent knowledge and proprietary big data knowledge through the lens of firm profitability as a knowledge transaction recipient. The proposed model can help those firms who purchase external knowledge choose the optimal knowledge structure and pricing strategies of two types of knowledge, and provide theoretical and methodological guidance for knowledge transaction recipient firms to negotiate with knowledge providers.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.111-118
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• 2019

Greenhouse gas emissions have a profound effect on global warming. Various environmental regulations have been introduced to reduce the emissions. The largest amount of greenhouse gases, including carbon dioxide, is produced in the steel industry. To decrease carbon dioxide emission, hydrogen-based iron oxide reduction, which can replace carbon-based reduction has received a great attention. Iron production generates various by-product gases, such as cokes oven gas (COG), blast furnace gas (BFG), and Linz-Donawitz gas (LDG). In particular, COG, due to its high concentrations of hydrogen and methane, can be reformed to become a major source of hydrogen for reducing iron oxide. Nevertheless, continuous COG cannot be supplied under actual operation condition of steel industry. To solve this problem, this study proposed to use two alternative COG-based fuel mixtures; one with natural gas and the other with biogas. Reforming study on two types of mixed gas were carried out to evaluate catalyst performance under a variety of operating conditions. In addition, methane conversion and product composition were investigated both theoretically and experimentally.

• Asia Marketing Journal
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• v.20 no.4
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• pp.1-19
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• 2019

This paper reports a case study of SevenBräu, the first company to acquire a license for small and medium scale beer manufacturing in Korea. This study explores how SevenBräu analyzed its consumers, competition, and environment to set its target market and successfully positioned itself to explore new markets in Korea. The company accomplished this through a mixture of marketing strategies with differentiated products and consumer benefits. SevenBräu has been growing fast and establishing its image as a "high-quality craft beer locally produced in a traditional way" and a "beer with regional characteristics," with young consumers (aged 20 to 35) as the main target. Such remarkable growth of SevenBräu can be attributed to factors such as: (1) product differentiation to satisfy the needs of consumers for taste, flavor, diversity, and freshness, (2) developing brands with regional characteristics and actively communicating its strategy through earned and owned media, and (3) sustainable management, considering both social value creation and environmental performance. Lastly, this case study presents challenges in the areas of brand management, value delivery network, and communication that SevenBräu needs to address in the beer market that faces increasing competition.

• Analytical Science and Technology
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• v.36 no.6
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• pp.281-290
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• 2023

Zidovudine is an antiretroviral agent prescribed for the prevention and treatment of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). It is typically recommended to be used in combination with other antiretroviral drugs. Zidovudine has the potential to generate N-nitrosodimethylamine (NDMA) in the presence of dimethylamine and nitrite salt under acidic reaction conditions during the drug manufacturing process. NDMA is a potent human carcinogen that may be detected in drug substances or drug products. An analytical method was developed to determine NDMA in pharmaceuticals including zidovudine using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analysis involved reversed-phase chromatography on a Kinetex F5 column with a mobile phase comprising water-acetonitrile mixtures. The detection of positively charged ions was conducted using atmospheric pressure chemical ionization (APCI). The calibration curve demonstrated excellent linearity (r = 0.9997) across the range of 1-50 ng/mL with a highly sensitive limit of detection (LOD) at 0.3 ng/mL. The developed method underwent thorough validation for specificity, linearity, accuracy, precision, robustness, and system suitability. This sensitive and specific analytical method was applied for detecting NDMA in zidovudine drug substance and its formulation currently available in the market, indicating its suitability for drug quality management purposes.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.4
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• pp.330-337
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• 2015

A bucket-brigade is a way of transporting items where items are passed from one person to the next. The operation of the bucket brigade imitates the cooperative behavior of ants when brood, food or other resources are moved. Koo (2009) presented a bucket brigade-based assembly cell where each worker follows a simple rule: perform assembly operations on a product until the next worker downstream takes it over; then go back to the previous worker upstream to take over a new assembly job. In this way, the flow line is self-balanced without any predetermined job assignment. However, there are some productivity losses related to hand-off and blocking. This paper examines the hand-off and blocking losses and presents a new bucket brigade-based assembly cell where working areas for each assembler is restricted with the help of buffer interfaces. Simulation experiments are used to validate the performance of the new assembly system.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.466-468
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• 2002

In order to newly define and specify the performance and the testing method of the high-voltage circuit breaker, IEC 62271-100 was published in May, 2001 and took place of IEC 60056 which had been used since 1987. This new standard intensifies the requirement and the test method of the circuit breaker and also domestic manufacturer makes progress the new product development. And, KERI also goes on the build-up project of short-circuit testing facilities for fulfilling the testing method requirements in new IEC 62271-100. This paper introduce the limiting method of short-circuit making current by controlling the time constant of dc component.

• 열병합발전
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• s.36
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• pp.16-21
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• 2003

For many years, T/G Supplier has constructed a number of thermal power plants and researched to improve the performance and the reliability of steam turbine, which are achieved by advances in design and materials technology. In recent, interest is renewed in advance steam condition as means of improving economy of thermal power plant and reducing environmental pollution. Improvements in the maximum power have been driven by the development of advanced rotor and bucket material and longer last stage bucket. Improvements in efficiency have been brought through advance in mechanical efficiency and thermodynamic efficiency. This paper describes a number of new steam path design features introduced to the steam turbine product. And also this paper describes new design technologies' development, new technologies' trend and technologies' development for ultra-super critical steam turbine.