• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.67.2-67.2
• /
• 2011

It is necessary to estimate empirical constants in order to predict the monthly mean daily global radiation on a horizontal surface in the developing areas for alternative energy. Therefore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for any areas over Korea by calculating the regression models taking into account latitude, percentage of possible sunshine, and cloud cover. From the results, the single linear equation proposed by using percentage of possible sunshine method shows reliable results for estimating the global radiation with average annual deviation of -3.1 to +0.6 % from measured values.

• Journal of Astronomy and Space Sciences
• /
• v.28 no.1
• /
• pp.71-77
• /
• 2011

Ionospheric error modeling is necessary to create reliable global navigation satellite system (GNSS) signals using a GNSS simulator. In this paper we developed algorithms to generate Klobuchar coefficients ${\alpha}_n$, ${\beta}_n$ (n = 1, 2, 3, 4) for a GNSS simulator and verified accuracy of the algorithm. The eight Klobuchar coefficients were extracted from three years of global positioning system broadcast (BRDC) messages provided by International GNSS service from 2006 through 2008 and were fitted with Fourier series. The generated coefficients from our developed algorithms are referred to as Fourier Klobuchar model (FOKM) coefficients, while those coefficients from BRDC massages are named as BRDC coefficients. The correlation coefficient values between FOKM and BRDC were higher than 0.97. We estimated total electron content using the Klobuchar model with FOKM coefficients and compared the result with that from the BRDC model. As a result, the maximum root mean square was 1.6 total electron content unit.

• Journal of the Korean Solar Energy Society
• /
• v.30 no.4
• /
• pp.15-21
• /
• 2010

Radiation data are the best source of information for estimating average incident radiation. Lacking this or data from nearby locations of similar climate, it is possible to use empirical relation ships to estimate radiation from days of cloudiness. It is necessary to estimate the regression coefficients in order to predict the daily global radiation on a horizontal surface. There fore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud cover. Particularly, the straight line regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of -0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.4
• /
• pp.368-373
• /
• 2004

A flow field in a passage with periodically converging-diverging cross-section is investigated experimentally by PIV measurement. A tube with a sinusoidally wavy cross section is one of several devices employed for enhancing the heat and mass transfer efficiency due to turbulence promotion and unsteady vortical motion. While the numerical flow visualization results have been limited to the fully developed cases, existing experimental results of this flow were simple qualitative ones by smoke or dye streak test. Therefore, the main purpose of this study is to produce quantitative flow data for fully developed and transient flow regime by the Correlation Based Correction PIV (CBC PIV) and to conjecture the analogy between flow characteristics and heat transfer enhancement with low pumping power. Another purpose of this paper is to examine the onset position of the transition and the global mixing, which results in transfer enhancement. At Re=2000, evidences of the global mixing are captured at 2.5 wavy module through the variation of RMS values and instantaneous velocity plot.

• Journal of the Korean Solar Energy Society
• /
• v.25 no.2
• /
• pp.9-17
• /
• 2005

Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. For the validation, estimated solar radiation fluxes are compared with observed solar radiation fluxes at 16 sites over the Korean peninsular from January 1982 to December 2004. Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.8 to +7.0% from the measured values and the yearly averaged horizontal global insolation of Korean peninsula was turned out to be $3.56kW/m^{2}/day$.

• Journal of the Korean Solar Energy Society
• /
• v.28 no.3
• /
• pp.1-6
• /
• 2008

It is necessary to estimate empirical constants in order to predict the monthly mean daily global radiation on a horizontal surface in the developing areas for alternative energy. Therefore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for any areas over Korea by calculating the regression models taking into account latitude, percentage of possible sunshine, and cloud cover. Results clearly demonstrates the reliability of the single linear equation for the estimation of global radiation, which is proposed by using percentage of possible sunshine method. When compared with the measured values, the average annual deviation falls between -3.1 to +0.6%.

• Journal of the Korean Solar Energy Society
• /
• v.22 no.3
• /
• pp.21-30
• /
• 2002

Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. For the validation. estimated solar radiation fluxes are compared with observed solar radiation fluxes at 16 sites over the Korean peninsular from January 1982 to December 2000. Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -5.6 to +2.8% from the measured values and the yearly averaged horizontal global insolation of Korean peninsula was turned out to be $3.038kcal/m^2.day$.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.50-55
• /
• 2009

Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. For the validation, estimated solar radiation fluxes are compared with observed solar radiation fluxes at 16 sites over the Korean peninsular from January 1982 to December 2007. Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.58 to +3.8% from the measured values and the yearly averaged horizontal global insolation of Korean peninsula was turned out to be $3.59kW/m^2/day$.

• Journal of Internet Computing and Services
• /
• v.24 no.5
• /
• pp.75-84
• /
• 2023

This study aims to investigate the influence of online entrepreneurship education on first-time entrepreneurs in western China. The research employed an online self-management survey method to collect data from participants involved in online entrepreneurship education and first-time entrepreneurs. The data was analyzed using SPSS and AMOS statistical software. The research findings indicate that online entrepreneurship education has a positive impact on entrepreneurial intention. There is a positive correlation between online entrepreneurship education and entrepreneurial execution capability. Entrepreneurial intention effectively promotes entrepreneurial execution capability, which is critical for successful entrepreneurship. Online entrepreneurship education also emphasizes the development of innovative abilities and thinking patterns, thereby enhancing the competitiveness of entrepreneurs. Additionally, entrepreneurial support plays a direct positive role in entrepreneurial success by providing resources, guidance, knowledge sharing, and confidence, thereby increasing the likelihood of success.

• Journal of the Korean Society of Industry Convergence
• /
• v.27 no.1
• /
• pp.195-205
• /
• 2024

This study is descriptive research study to understand the impact of digital ethics-literacy, multicultural acceptance, and global citizenship of medical students' on cultural competency. The subjects for this study were the medical students of J city of Province of G, collecting data from first of October to 15th of October 2023. The tools used for this study consist of 178 questions which were 9 questions of general properties, 70 questions of digital ethics-literacy, 35 questions of multicultural acceptance, 3qustions of global citizenship and 33 questions of cultural competency. As a result of this study, the score of digital ethics-literacy was 2.67±0.85(out of 5), the score of multicultural acceptance was 3.62±1.08(out of 6), the score of global citizenship was 3.72±0.75(out of 5), and the score of cultural competency was 3.49±0.71(out of 5). There is a positive correlation between multicultural acceptance and global citizenship. The global citizenship was the factor affecting significantly on cultural competency. The power of explication was 20.8%. The education for accepting and understanding cultural diversity and offering opportunity of domestic and overseas volunteering programs so that global citizenship could be improved. There is also a need of development of integrative education programs in terms of multicultural education including direct and indirect digital media education which can perform medical service for various multicultural recipient on the medical site not an one-shot instiiled displine.