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Kyonju, South Korea

Gyeongju University is a privately run, 4-year university located in Gyeongju, North Gyeongsang province, South Korea. Wikipedia.

Kim K.W.,Gyeongju University
Journal of the Korean Physical Society

Visibility change can be perceived on a few-hour interval in real-time. In general, the light attenuation coefficients of an aerosol can be obtained by continuous measurements in the open path, thus provide real-time behavior for the aerosol optical properties. In order to characterize the chemical composition of particulate matters and their optical properties in the atmosphere, a complementary time and size-resolved collection for particulate matters is required. In this study, the mass concentrations of the elements reconstructing fine soil mass were analyzed using a proton induced X-ray emission (PIXE) method. Size-resolved particles of PM1.0, PM2.5, and PM10 were collected using cyclones with denuder systems during the summer and the fall intensive monitoring periods. A transmissometer, a nephelometer, and an aethalometer produced the light extinction, the scattering, and the absorption coefficients, respectively. Light extinction budgets for visibility impairing aerosol components were calculated using the well-known hygroscopic growth factors for ammonium sulfates, ammonium nitrates, and organics in the small and large particles size modes. During the intensive monitoring periods, the visual range was seriously reduced to less than 5 km due to high mass loading of PMs and increase of relatively humidity. NHSO was the largest contributor to light extinction. The light extinction coefficients are well correlated to PM10, PM2.5, and PM1.0, leading to mass extinction efficiencies of 4.6, 7.2, and 12.6 m2 g-1, respectively, in wet condition. Contributions of NHSO, NHNO, and OMC to light extinction increased in the large particle size mode than in the small particle size mode during the diurnal variation of the seriously hazy days. These results were obtained from the time-resolved mass concentrations of elements converting to light attenuating chemical species. An assessment of the variations of optical properties in real-time is possible because the PIXE method provides time-resolved measurement data. Source

Pourdana N.,Islamic Azad University at Karaj | Pourdana N.,Gyeongju University
International Journal of Applied Linguistics and English Literature

This study is an endeavor to demonstrate the presence of various kinds of cohesive devices through English Textbook and their possible impacts on Iranian High school students’ reading comprehension. . To homogenize the subjects and divide them into two intact groups of experimental and control, Nelson Battery Test of English was administered as the pre-test. In the 12-session treatment, the experimental group read through eight selected short passages from Learning to Read English (Birjandi, AnaniSarab & Samimi 2000) for 20 minutes per session, while the control group practiced the questions in English final exams back to previous academic years as a placebo. Both groups partook in a piloted and validated post-test. Four passages, extracted from the University Entrance Examinations in 2006, 2007, 2009 and 2011 in Iran, were read and followed by 20 multiple-choice items. The post-test was piloted and revised for an acceptable reliability estimate (Cronbach α=.761). The collected data were analyzed for normality with Kolmogorov-Smirnov Test. Statistics from pre- and post-tests supported the benefits Iranian high school EFL learners would gain from a high frequency of cohesive devices in their reading texts. Moreover, the EFL learners' moderately improved proficiency level accounted for the benefits they would gain from English texts flourished with frequent cohesive devices. Findings could have some important pedagogical implications in favor of explicit teaching of cohesive devices by EFL teachers and material developers. © Australian International Academic Centre, Australia. Source

A simple distortion-invariant optical identification (ID) tag is presented for real-time vehicle identification and verification. The proposed scheme is composed of image encryption, ID tag creation, image decryption, and optical correlation for verification. To create the ID tag, a binary-phase computer-generated hologram (BPCGH) of a symbol image representing a vehicle is created using a simulated annealing algorithm. The BPCGH is then encrypted using an XOR operation and enlargement transformed into polar coordinates. The resulting ID tag is then attached to the vehicle. As the BPCGH consists of only binary phase values, it is robust to external distortions. To identify and verify the vehicle, several reverse processes are required, such as capturing the ID tag with a camera, extracting the ID tag from the captured image, transformation of the ID tag into rectangular coordinates, decryption, an inverse Fourier transform, and correlation. Computer simulation and experimental results confirm that the proposed optical ID tag is secure and robust to such distortions as scaling, rotation, cropping (scratches), and random noise. The ID tag can also be easily implemented, as it consists of only binary phase components. © 2010 Society of Photo-Optical Instrumentation Engineers. Source

Park S.S.,Chonnam National University | Cho S.Y.,Chonnam National University | Kim K.-W.,Gyeongju University | Lee K.-H.,Kyungil University | Jung K.,Seoul Metropolitan Government Research Institute of Public Health and Environment
Atmospheric Environment

Concentrations of carbonaceous aerosols in PM 2.5, including elemental carbon (EC), organic carbon (OC), bulk water-soluble organic carbon (WSOC), fractionated WSOCs, and water-soluble inorganic species were measured between December 27, 2010 and January 20, 2011, at an urban site of Seoul, Korea. PM 2.5 samples were collected twice a day, e.g., for the daytime (10:00-16:00) and nighttime (16:00-10:00), respectively. A macro-porous XAD7HP resin was used to separately group the liquid extracts into hydrophilic and hydrophobic WSOC (WSOC HPI and WSOC HPO). To better understand the contributions of primary and secondary OC (SOC) to WSOC, estimates of SOC were derived using the EC-tracer method and compared with the WSOC fractions. Good correlations among the WSOC, SO42-, and oxalate suggest that some of the observed WSOC originated from similar formation processes as those of SO42- and oxalate, i.e., formed by an in-cloud or aerosol droplet process. Primary OC was more highly correlated with the WSOC HPO (R 2 = 0.56) than the WSOC HPI (R 2 = 0.33), while a better correlation between predicted SOC and WSOC HPI (R 2 = 0.63) was found than between the predicted SOC and WSOC HPO (R 2 = 0.47). These results suggest that WSOC HPI at the site during the winter could be formed by a similar production pathway such as the secondary organic carbon, while primary combustion emissions were a dominant source for the WSOC HPO during the study period. Sources of WSOC, WSOC HPI and WSOC HPO inferred based on the correlations were also clearly demonstrated by source categories identified by principle component analysis. Measurement results suggest that group separation of bulk WSOC extracts could provide important clues for better understanding the sources of OC (or WSOC). © 2012 Elsevier Ltd. Source

Joo J.,Gyeongju University
Journal of Theoretical and Applied Electronic Commerce Research

The buyer’s trust in seller in consumer to consumer e-commerce plays a critical role in consumer purchase decisions. Thus, this paper aims at analyzing the relationships between buyer’s trust in seller, price discount, and price premium by using product price as a moderator variable. A trust function for sellers was calculated through a questionnaire, by using the feedback mechanism and by applying Analytical Hierarchy Process. Our empirical study, using historical transaction data, indicates that buyer’s trust in seller in the case of an expensive product is more important than that in an inexpensive product. Buyers’behavior when purchasing a higher-priced product was more sensitive to the buyer’s trust in seller than to product price. Product price played the role of a moderator variable in the relationship between buyer’s trust in seller and price discount. However, there was no evidence that product price performs the function of a moderator variable in the relationship between buyer’s trust in seller and price premium. © 2015 Universidad de Talca - Chile. Source

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