• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.538-543
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• 2003

Perforated wall has long been employed to control a variety of flow phenomena. It has been, in general, characterized by a porosity of the perforated wall. However, this porosity value does not take account of the number and detailed shape of porous holes, but is defined by only the ratio of the perforated area to total wall surface area. In order to quantify the porous wall effects on the flow control performance, an effective porosity should be known with the detailed flow properties inside the porous holes. In the present study, a theoretical analysis using a small disturbance method is performed to investigate detailed flow information through porous hole and a computational work is also carried out using the two-dimensional, compressible Navier-Stokes equations. Both the results are compared with existing experimental data. The gasdynamical porosity is defined to elucidate the effect of perforated wall.

• Journal of Welding and Joining
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• 제15권6호
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• pp.105-115
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• 1997

A numerical study is performed to predict the thermal response of a detailed card assembly during infrared reflow soldering. The card assembly is exposed to discontinuous infrared panel heater temperature distributions and high radiative/convective heating and cooling rates at the inlet and exit of the oven. The convective, radiative and conduction heat transfer within the reflow oven as well as within the card assembly are simulated and the predictions illustrate the detailed thermal responses. The predictions show that mixed convection plays an important role with relatively high frequency effects attributed to buoyancy forces, however the thermal response of the card assembly is dominated by radiation. The predictions of the detailed card assembly thermal response can be used to select the oven operating conditions to ensure proper solder melting and minimization of thermally induced card assembly tresses and warpage.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.129.2-129.2
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• 2011

Knowledge of the detailed solar radiation components are essential for modeling many solar systems. This is particularly the case for applications that concentrate the incident energy to attain high photo-dynamic efficiency achievable only at the higher intensities. In order to estimate the performance of concentrating solar systems, it is necessary to know the intensity of the beam radiation, as only this component can be concentrated. The Korea Institute of Energy Research(KIER) has began collecting detailed solar radiation component data since August, 1988. KIER's component data will be extensively used by solar system users or designers as well as by research institutes.

• 한국초등과학교육학회지:초등과학교육
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• 제20권1호
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• pp.75-89
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• 2001

The purpose of this study is to get the more qualified elementary science teacher's guide as a major curriculum material for teachers and to find more improvement suggestions by analyzing of the teachers' perception and using status of it. To examine the problems of this study, 183 teachers from the elementary schools were surveyed by the questionnaire that was developed by researcher, and statistical technique for data analysis was frequency, using SPSS win(version 7.5). Teachers generally thought that the general remarks of the elementary science teacher's guide were helpful to understand elementary science education and the detailed subjects were useful, but teachers less satisfied about 'practice of teaching' of the detailed subjects. The most interested sector of the teachers' was the sector of the teaching methods. The results of this study were that the sector' the methods and evaluation of the elementary science education' of the general remarks and the sector' practice of teaching' of the detailed subjects were mostly interested. So it is necessary to be more detailedly guided when the development of the elementary science teacher's guide are considered.

• Mycobiology
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• 제41권1호
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• pp.13-17
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• 2013

Hypotrachyna (Vainio) Hale is a somewhat rare lichen genus found on the Korean Peninsula. Since it was first recorded more than two decades ago, no detailed taxonomic or revisionary study of the genus has been conducted. Thus, the present study was conducted to carry out a detailed taxonomic and revisionary study of Hypotrachyna in South Korea. This study was based on specimens deposited in the Korean Lichen Research Institute (KoLRI). Detailed taxonomic studies and a literature review confirmed the presence of seven species of Hypotrachyna from South Korea, including one new record, Hypotrachyna nodakensis (Asahina) Hale. Descriptions of each species with their morphological, anatomical and chemical characters together with a key to all known Hypotrachyna species are presented.

• 교육녹색환경연구
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• 제11권2호
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• pp.38-50
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• 2012

The purpose of this study was to Improvement proposal on Item and Detailed Method for Education Environment Evaluation, Focused on School Location. This Study are as follows. 1. Research on Location Theory and relation Law 2. Improving research by School Experts(Health&construction& administration) 3. Present a Detailed quantitative assessment criteria 4. Pilot Survey on Education Environment Evaluation So, this result will be used in decision-making-process of land use planning, public land development construction, urban design and city policy.

• Journal of Information Technology Applications and Management
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• 제14권3호
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• pp.151-168
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• 2007

RFID is an emerging technology and rapidly applied to various industries due to its high-tech characteristic and convenience. Although RFID provides valuable benefits. it might also generate serious privacy problems. Previous studies show that privacy issues should be incorporated in developing RFID systems and more detailed privacy protection methods. However. they just provide basic concept, rough guideline. and simple architecture about RFID privacy protection. Industry needs more structured framework and detailed systematic process to incorporate privacy issues into the RFID system. The purpose of this paper is to develop a framework and detailed process design of RFID privacy protection issues in retail industries. A framework is developed based on individual sensitivity concept, RFID contents, and interface with EPC global standard. Case study is applied to validate the framework and it turns out to be useful. It is expected that the proposed framework and process design would provide more systematic guide lines to solving RFID privacy problems.

• Earthquakes and Structures
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• 제14권6호
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• pp.551-565
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• 2018

Experimental testing is considered the most realistic approach to obtain a detailed representation of the nonlinear behaviour of masonry-infilled reinforced concrete (RC) structures. Among other applications, these tests can be used to calibrate the properties of numerical models such as simplified macro-models (e.g., strut-type models) representing the masonry infill behaviour. Since the significant cost of experimental tests limits their widespread use, alternative approaches need to be established to obtain adequate data to validate the referred simplified models. The proposed paper introduces a detailed finite element modelling strategy that can be used as an alternative to experimental tests to represent the behaviour of masonry-infilled RC frames under earthquake loading. Several examples of RC infilled frames with different infill configurations and properties subjected to cyclic loading are analysed using the proposed modelling approach. The comparison between numerical and experimental results shows that the numerical models capture the overall nonlinear behaviour of the physical specimens with adequate accuracy, predicting their monotonic stiffness, strength and several failure mechanisms.

• 한국연소학회지
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• 제16권2호
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• pp.16-22
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• 2011

It is a challenging task to apply large detailed chemical mechanisms of fuel oxidation in simulation of complex combustion phenomena. There exist a few systematic methodologies to reduce detailed chemical mechanisms to smaller sizes involving less computational load. This research work concerns generation of a skeletal chemical mechanism by a directed relation graph with specified accuracy requirement. Two sequential stages for mechanism reduction are followed in a perfectly stirred reactor(PSR) for high temperature chemistry and to consider the autoignition delay time for low and high temperature chemistry. Reduction was performed for the detailed chemical mechanism of n-heptane consisting of 561 species and 2539 elementary reaction steps. Validation results show acceptable agreement for the autoignition delay time and the PSR calculation in wide parametric ranges of pressure, temperature and equivalence ratio.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.251-255
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• 2015

Unsteady Shock-Induced Combustion has been studied for the past few decades since it is considered as one of the potential ways to reach supersonic flights. Experimental observations of Unsteady SIC were observed as early as 1960's. But Lehr was the first to report in detail the mechanisms of Shock-Induced Combustion experimentally. Numerical Studies on SIC were helpful in explaining the insight into the oscillatory behaviour in the mid 90's to early 2000's. Detailed reaction mechanisms is required to prediction the SIC flowfield more in detail. However at that time, very few reaction mechanisms on hydrogen-oxidation were reported. In the last decade, various number of hydrogen reaction mechanisms were reported. In this study, an attempt has been made to analyze the effect of various reaction mechanisms in an unsteady mode of Shock-Induced Combustion.