• Tribology and Lubricants
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• 제15권2호
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• pp.141-149
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• 1999

Fracture, fatigue and wear characteristics of Al-Si alloy used for compressor are experimentally studied. Plane strain fracture toughness test is carried out using three point bending specimen. Fatigue test is performed under constant loading condition and wear test is carried out as a function of sliding velocity and applied load. To obtain the crack propagation characteristics and wear mechanism of Al-Si alloy, fracture and worn surfaces are investigated using SEM. It is verified that fracture and fatigue strength of Al-Si alloy are improved by the fine microstructure of alloy. The wear behavior and specific wear amount of Al-Si alloy are not dependent on the microstructure but on a function of the silicon content. Anodizing on the surface of Al-Si alloy, surface hardness and wear characteristics are improved.

• International Journal of Aeronautical and Space Sciences
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• 제16권1호
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• pp.64-76
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• 2015

This paper suggests applying pseudospectral model predictive method for exo-atmospheric guidance. The method is a fusion of pseudospectral law and model predictive control, in which a two point boundary value problem is formulated using model predictive approach and solved by applying pseudospectral law. In this work, the method is applied to exo-atmospheric guidance with specific target requirement. The existing exo-atmospheric guidance methods suffice general requirements for guidance, but cannot ensure specific target constraints; whereas, the presented method is able to do so. The proposed guidance law is assessed through simulation of perturbed cases, and the tests suggest that the method is able to operate semi-autonomously under control and thrust vector perturbations.

• 한국경영과학회지
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• 제20권3호
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• pp.17-29
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• 1995

Recently, neural network models have been employed as an alternative to regression analysis for point estimation or function fitting in various field. Thus far, however, no theoretical or empirical guides seem to exist for selecting the tool which the most suitable one for a specific function-fitting problem. In this paper, we evaluate performance of three major function-fitting techniques, regression analysis and two neural network models, back-propagation and linear-Hebbian-learning neural networks. The functions to be fitted are simple linear ones of a single independent variable. The factors considered are size of noise both in dependent and independent variables, portion of outliers, and size of the data. Based on comutational results performed in this study, some guidelines are suggested to choose the best technique that can be used for a specific problem concerned.

• 한국컴퓨터정보학회논문지
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• 제21권12호
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• pp.91-96
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• 2016

In this paper, we propose the CRM service model for analyzing and managing location based data collected by Wi-Fi and BLE. As mobile devices became personalized, enterprises became interested in individual location, and location based mobile marketing started to stand on spotlight. Location based proximity marketing is developing along with contactless data transmission technology, and payment system that uses NFC, Beacon that utilizes BLE, as well as advertisement via Wi-Fi are being serviced. We suggest the model that mobile devices can be detected and identified by MAC address with the need of being connected to Wi-FI or Bluetooth interface. MAC addresses are not associated with any specific user account or mobile phone number. The idea is to be able to measure the amount of people which are present in a certain point at a specific time, allowing the study of the evolution of data analysis and offers effective information for decision-makings.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1987년도 식물생명공학 심포지움 논문집 Proceedings of Symposia on Plant Biotechnology
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• pp.283-307
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• 1987

Glycinin and $\beta$-conglycinin are the most abundant storage protein in soybean. These proteins are known to be synthesized predominantly during germination and cell expansion phase of seed development for short period, and synthesized not in other tissues. Genes encoding these storage proteins are useful system to study the mechanism of development stage and tissue specific gene expression in eukaryotes, especially plants, at the molecular level. The cDNA and genomic clones coding for glycinin have been isolated and regulation mechanism of the gene expression has been studied. Initially, development and tissue-specific expression of the glycinin gene is regulated at the level of transcription. Post-transcriptional processing is also responsible for delayed accumulation of the mRNA. Translational control of the storage protein gene has not been reported. Post-translational modification is another strategic point to regulate the expression of the gene. It is possible to identify positive and/or negative reguratory clements in vivo by producing transgenic plants agter gene manipulation. Elucidation of activation and repression mechanism of soybean storage protein genes will contribute to the understanding of the other plant and eukaryotic genes at molecular level.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.529-532
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• 2004

As the purpose of this study is a research of series to obtain fundamental data on the development of the product of foamed concrete using bottom ash for various applications in the field, the main purpose is the light weight of product of concrete. In this experiment, method of mixing of foam is very important because it control specific gravity and strength of the product. As the test results, it was found that regardless of mixing method the grower the concentration of foaming agent the lower the specific gravity and the compressive strength of the specimen especially pre-foaming method. From a strength point of view, we knew that mix-foaming method and steam curing is efficient to obtain a adequate compressive strength of foamed concrete.

• 한국의류학회지
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• 제26권8호
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• pp.1228-1238
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• 2002

This study attempted to identify that how the meaning of clothes and clothing behavior were extended, and to examine that they, produce what kinds of meaning in the specific contort in a novel, the Honpul. The Frame of meaning analysis proposed by Beaugrande, Dressier, and Damesteter was used as an analyzing method. The 100 texts were collected for analysis from the Honpul volume 1 to 10. Psychological meanings were categorized to sensitivity meaning, disposition meaning and incantation meaning. Those had not only a basic meaning which could be gotten from the practical clothing but also second and third extended meanings. The point of this study was to present a new method and possibility for analyzing the code of costume culture by the extended meanings in novels.

• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 1999년도 추계학술대회
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• pp.557-575
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• 1999

The task evaluating science and technology is becoming more important in every country trying to develop and improve overall national R&D capability in an effort to sustain national prosperity and public welfare. However, the way in which evaluation organisation is approached in each country may differ from nation to nation reflecting national R&D systems and S&T policies as well as the specific roles of scientists and policy- makers at various levels. Over the past two decades or so, Korean evaluation system has been transplanted form the West and they modified, In addition, Korea borrowed elements from the Japanese. Whether such systems have been well rooted in our specific circumstances is a critical question. In this context, it would be meaningful to diagnoses the current Korean evaluation system and also makes some suggestions for improving this system. For this purpose, this paper also attempts to approach to the theoretical aspects of evaluation as a starting-point.

• Nuclear Engineering and Technology
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• 제50권5호
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• pp.698-708
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• 2018

This article introduces a methodology of designing a wavelet operator suitable for multiscale modeling. The operator matrix transforms states of a multivariable system onto projection space. In addition, it imposes a specific structure on the system matrix in a multiscale environment. To be specific, the article deals with a diagonalizing transform that is useful for decoupled control of a system. It establishes that there exists a definite relationship between the model in the measurement space and that in the projection space. Methodology for deriving the multirate perfect reconstruction filter bank, associated with the wavelet operator, is presented. The efficacy of the proposed technique is demonstrated by modeling the point kinetics nuclear reactor. The outcome of the multiscale modeling approach is compared with that in the single-scale approach to bring out the advantage of the proposed method.

• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.34-42
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• 1998

Three hardwood (ash, alder and black locust) and three softwood (Japanese red pine, radiata pine and Western hemlock) specimens were dried in microwave(MlW) oven and their drying rates were obtained. Their specific permeabilities were also measured by using a modified liquid permeability measuring device. The correlation between the M/W drying rates and permeabilities of six species were statistically analyzed. It was revealed that within a species there is a logarithmic relationship between the M/W drying rates and average moisture contents and that among species there is a linear relationship between the M/W maximum drying rates and the average specific permeabilities. A exception was Western hemlock, which was of low permeability and of high drying rate. A Me-time equation, which showed a good agreement with the actual data, was derived. Thus using this equation the moisture contents of wood and the drying end points of M/W drying could be predicted. Infrared images of the thermal distribution in wood were illustrated.