• Wind and Structures
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• v.17 no.2
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• pp.135-162
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• 2013

The majority of experiments to characterize the turbulence in the surface layer have been performed in flat, open expanses. In order to characterize the turbulence in built-up terrain, two mobile towers were deployed during Hurricane Ike (2008) in close proximity, but downwind of different terrain conditions: suburban and open. Due to the significant non-stationarity of the data primarily caused by changes in wind direction, empirical mode decomposition was employed to de-trend the signal. Analysis of the data showed that the along-wind mean turbulence intensity of the suburban terrain was 37% higher than that of the open terrain. For the mean vertical turbulence intensity, the increase for the suburban terrain was as high as 74%, which may have important implications in structural engineering. The gust factor of the suburban terrain was also 16% higher than that of the open terrain. Compared to non-hurricane spectral models, the obtained spectra showed significantly higher energy in low frequencies especially for the open terrain.

• Journal of Information Technology Services
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• v.10 no.2
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• pp.1-20
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• 2011

Due to the wide use of internet, electronic commerce market is gradually increasing but consumers still conceive various transaction-related problems. Various studies argue that those problems are obstructing trust in electronic commerce. Most studies on electronic commerce address that trust is measured as a Single dimension in which factors obstructing trust are same as those of increasing distrust. However, this study doesn't view trust as a single dimensional level but understands trust and distrust are bidimensional. This study also holds a viewpoint that they are influenced by different antecedents. According to the results of empirical analysis, the antecedents of trust have a significant explanatory power to trust and those of distrust have it to distrust. Other relations among the notions of trust and distrust, perceived risk and purchase intention as depicted in the research model are all statistically significant except the relation between distrust and purchase intention. This study shows a strong evidence of the bidimensionality of trust with separate antecedents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.208-213
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• 2002

We present the temperature and excitation power density dependence of the photoluminescence from carbon-doped GaAs epilayers grown on GaAs (311)A substrate by atmospheric pressure metalorganic chemical vapor deposition. The measured temperature dependence of the PL peak energy is well expressed by an empirical formula proposed by Varshni. The thermal quenching mechanism of the intensity of 16 K luminescence peak at 1.480 eV is described with the dominant activation energy of 27$\pm$2 meV. The activation energy shows an evidence that the emission band involves the carbon acceptor in the recombination process.

• Proceedings of the KSRS Conference
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• v.1
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• pp.344-347
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• 2006

China Coastal Water (CCW) usually appears in the seas surrounding Jeju Island annually (June?October) and is very pronounced in August. The power spectrum density (PSD), sea level anomalies (SLAs), and sea surface temperatures (SSTs) were found to peak annually and semiannually. The peaks at intervals of 80-, 60-, and 43-days are considered to be influenced by CCW and the Kuroshio Current. Generally, low-salinity water appears to the west of Jeju Island from June through October and gradually propagates to the east, where CCW meets the Tsushima Current. Empirical orthogonal function (EOF) analysis of SLAs and SSTs indicated that the variance in SLAs and SSTs was 55.70 and 98.09% in the first mode, respectively. The PSD for the first mode of EOF analysis of SLAs was stronger in the western than in the eastern waters because of the influence of CCW. The PSD for the EOF analysis of SSTs was similar in all areas (the Yangtze Estuary and the waters to the west and east of Jeju Island), with a period of approximately 260 days.

• English Language & Literature Teaching
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• v.15 no.3
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• pp.59-81
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• 2009

The primary goal of this paper was to develop a critical point of view to critical pedagogy when applied to EFL contexts. Critical pedagogy is more concerned about how language can affect personal and social change of teachers and students than it is with how to teach language effectively or in ways that encourage critical thinking on the part of teacher and students. For this goal, this paper introduces the definition, emergence and major constructs of critical pedagogy in a broad way at first. Then, this paper presents how critical pedagogy has an impact on ELT, focusing on how critical pedagogy is applied in ELT contexts and why the application of critical pedagogy in EFL can be criticized, through the review of empirical studies. Reflection of Korean English teaching situation and applicational difficulties of critical pedagogy in Korean ELT are followed.

• The Journal of Information Systems
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• v.13 no.2
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• pp.155-172
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• 2004

The purpose of this study is to investigate factors which can lead small buyers to participate in a Reverse Aggregation Electronic Market (RAEM). Five factors including search, selection, price, delivery, and Internet literacy were selected as possible factors which are expected to influence small buyers' participation in a RAEM. This paper focused on a RAEM of the Korean automotive industry in which the third party aggregator formed a group of small automobile repair shops (ARS) and amassed buying power for them by building a buyer' oriented electronic market (EM). Survey data were collected from small ARS in South Korea. The results of the empirical analysis indicated that fast delivery and support for Internet illiteracy are potential incentives that could influence buyers' decisions to join a RAEM.

• The KSFM Journal of Fluid Machinery
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• v.17 no.3
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• pp.33-40
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• 2014

In this study, a new model for calculating the liquid film thickness and condensation heat transfer coefficient in a vertical condenser tube is proposed by considering the effects of gravity, liquid viscosity, and vapor flow in the core region of the flow. In order to introduce the radial velocity profile in the liquid film, the liquid film flow was regarded to be in Couette flow dragged by the interfacial velocity at the liquid-vapor interface. For the calculation of the interfacial velocity, an empirical power-law velocity profile had been introduced. The resulting liquid film thickness and heat transfer coefficient obtained from the proposed model were compared with the experimental data from other experimental study and the results obtained from the other condensation models. In conclusion, the proposed model physically explained the liquid film thinning effect by the vapor shear flow and predicted the condensation heat transfer coefficient from experiments reasonably well.

• The Journal of Information Systems
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• v.11 no.1
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• pp.105-127
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• 2002

The objective of this study is to analyze factors affecting usage of b2b e-marketplace. For this purpose, we suggest a research framework where the factors are e-business infrastructure, expectation of competitive advantages and perceived barriers with current and future usages as result variables. For empirical test, 219 companies are surveyed and 177 valid ones among them are analyzed. In result, e-business infrastructure and competitive advantage affect to both current and future usage positively and perceived barriers affect to future usage negatively. The results shows the following two: First, many companies expect improvement of competitive advantages such as bargaining power and efficiency by usage of e-marketplace. Second, for more aggressive usage of e-marketplace, it is important not only to build e-business infrastructure but also to resolve perceived barriers.

• Journal of Information Display
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• v.13 no.1
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• pp.37-42
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• 2012

An empirical functional form was suggested for the analysis of the emission spectrum of high-power light-emitting diode (LED) consisting of a sharp blue peak from the LED chips and a broad yellow peak from the phosphor layer. The peak positions, half widths, shape parameters, and amplitudes of these two peaks were reliably obtained as a function of the temperature, and the results were discussed qualitatively in relation with the junction temperature. The adoption of an inert liquid was found to have significantly reduced the LED temperature and the color shift of the emitted light. The phenomenological approach used in this study may be helpful in the simulation of the LED spectrum under various thermal conditions, and may thus be helpful in the improvement of the device performance.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.659-661
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• 1989

$CO_2$ laser beam was focused a ZnSe lens onto the center of the occlusal surface of extracted lower molars. K-type thermocouple was contacted with the pulp chamber and the changes of temperature in the pulp chamber during and after the laser irradiation were measured as function of the power of laser beam, the time of laser irradiation and thickness of the sample. An empirical formula for temperature effect was derived from the measured data.