• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.1
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• pp.29-43
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• 2022

This study measures the realized rate of return of venture capital(VC) fund at the level of investment agreement(as opposed to fund level returns reported by most of the relevant studies). It also measures the stock price return of the VC's portfolio firms (unlisted start-ups) at firm level(as opposed to fund returns) and its variance for the first time using unique data of the VC funds held by the Korean Venture Capital Association. Results of the analysis confirm that VC fund returns exceed individual stock price returns. Additionally, it is confirmed that VC portfolio firms exhibit a positive relationship between risk and return measured by total risk. Finally, we find that stock price returns at firm level are lower than that implied by the associated levels of risk. Consequently, this may make individual investors hesitate to directly buy unlisted startups' stocks even when investment in individual startup companies guarantees high risk-high returns relationship.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.111-116
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• 2015

The purpose of this study was to evaluate mixed model of dbh-height relation containing random effect. Data were obtained from a survey site for Quercus variabilis in Gangwon region and remeasured the same site after three years. The mixed model were used to fixed effect in the dbh-height relation for Quercus variabilis, with random effect representing correlation of survey period were obtained. To verify the evaluation of the model for random effect, the akaike information criterion (abbreviated as, AIC) was used to calculate the variance-covariance matrix, and residual of repeated data. The estimated variance-covariance matrix, and residual were -0.0291, 0.1007, respectively. The model with random effect (AIC = -215.5) has low AIC value, comparison with model with fixed effect (AIC = -154.4). It is for this reason that random effect associated with categorical data is used in the data fitting process, the model can be calibrated to fit repeated site by obtaining measurements. Therefore, the results of this study could be useful method for developing model using repeated measurement.

• Journal of KIISE:Information Networking
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• v.35 no.6
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• pp.474-481
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• 2008

Scanning worm increases network traffic load and result in severe network congestion because it is a self-replicating worm and send copies of itself to a number of hosts through the Internet. So an early detection system which can automatically detect scanning worms is needed to protect network from those attacks. Although many studies are conducted to detect scanning worms, most of them are focusing on the method using packet header information. The method using packet header information has long detection delay since it must examine the header information of all packets entering or leaving the network. Therefore we propose an algorithm to detect scanning worms using network traffic characteristics such as variance of traffic volume, differentiated traffic volume, mean of differentiated traffic volume, and product of mean traffic volume and mean of differentiated traffic volume. We verified the proposed algorithm by analyzing the normal traffic captured in the real network and the worm traffic generated by simulator. The proposed algorithm can detect CodeRed and Slammer which are not detected by existing algorithm. In addition, all worms were detected in early stage: Slammer was detected in 4 seconds and CodeRed and Witty were detected in 11 seconds.

• Journal of the Korean Data and Information Science Society
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• v.22 no.2
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• pp.287-296
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• 2011

Thirty six female students participated in the experiment of the fat mass weight loss. they kept diary for foods they ate every day, took a picture of the foods, transmitted the picture to the experimenter by the camera phone, and consulted him about fat mass loss once a week for 8 weeks period. Fat mass weight and its related factors of the students had been measured repeatedly every week during 8 weeks, The repeated measurement data were used for applying various random coefficient models. And hence optimal random coefficient model was selected. From the optimal model, the baseline, body mass index, diastolic blood pressure, total cholesterol and time of the fixed factors were very significant. The fixed quadratic time effect existed. The variance components corresponding to the subject effect, linear time effect of the random coefficients were all positive. Thus random coefficients up to the linear terms were considered as the optimal model. The treatment effect reduced the weight loss to an average of 2.1kg at the end of the period.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1191-1197
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• 2003

In the multi-carrier OFDM communication system, the inter-carrier-interference(ICI) produced by phase noise in the transceiver local oscillator makes a severe influence on the system performance. In this paper, a new ICI self-cancellation scheme in the data-conversion type is proposed to reduce effectively the ICI. Also, the common phase error(CPE), ICI and carrier to interference power ratio(CIR) are found by the linear approximation of the phase noise. Then, the proposed method is compared with the conventional OFDM to analyze the efficiency of system performance improvement. When the number of subcarriers is 64, there are respectively the SNR gain of 0.6 ㏈ in the phase noise variance of 0.3 with QPSK and 1.5 ㏈ in the phase noise variance of 0.1 with 16 QAM at BER=10$\^$-3/. As a result, the performance degradation by ICI can be effectively lowered in the proposed system with ICI self. cancellation scheme, compared with the conventional OFDM system.

• Korean Journal of Occupational Health Nursing
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• v.28 no.4
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• pp.197-207
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• 2019

Purpose: This study aimed to examine the relationship between organizational health (OH), safety climate (SC), the nursing working environment (NWE), and engagement in patient safety management activities (PSMA) among operating room nurses and identify the factors that predict engagement in PSMA. Methods: From August 10th to 25th, 2018, 176 operating room nurses who were working in tertiary and general hospitals responded to a structured questionnaire. Using SPSS/WIN 25.0, the collected data were subjected to independent-samples t-test, one-way analysis of variance, Scheffe?test, and Pearson's correlational and multiple stepwise regression analyses. Results: OH and SC were significantly correlated with engagement in PSMA. The factors that predicted engagement in PSMA were OH, NWE, participation in accreditation, years of work experience, and hospital size; together, they explained 17% of the variance in engagement in PSMA. Conclusion: This study revealed that OH has a significant influence on engagement in PSMA among operating room nurses. Therefore, hospitals should aim to create healthy working environments to promote engagement in PSMA among operating room nurses, actively delegate responsibilities to increase their level of participation in accreditation, and implement strategies that maintain high levels of nurse retention.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.155-162
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• 2008

This study shows how to estimate the design hour factor when the counting stations don't have all of the hourly volumes such as in a coverage survey. A coverage survey records traffic volume from 1 to 5 times in a year so it lacks the detailed information to calculate the design hour factor. This study used the traffic volumes of permanent surveys to estimate the design hour factor in coverage surveys using correlation and regression analysis. A total 7 independent variables are used : the coefficient of variance of hourly volume, standard deviation of hourly volume, peak hour volume, AADT, heavy traffic volume proprotion, day time traffic volume proportion and D factor. All of variables are plotted on a curve, so it must use non-linear regression to analyze the data. As a result the coefficient of determination and MAE are good at logarith model using AADT.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.200-204
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• 2006

Purpose: Determination of pulmonary to systemic blood flow ratio (QP/QS) is important for the management of patients with left-to-right shunt. This study was performed to assess the agreement of Qp/Qs ratio using the radionuclide method and oxymetry, to investigate the factors influencing the agreement, and to know how interchangeable the results of each technique. Materials and Methods: We compared the Qp/Qs measured by single-pass radionuclide angiocardiography and oxymetry during catheterization in 207 patients who underwent both studies. In radionuclide method, Qp/Qs was calculated from the pulmonary time-activity curves using a gamma variate fit. The correlation and Bland-Altman analysis were performed according to the levels of shunt and associated lesions. Results: The mean Qp/Qs was $1.83{\pm}0.50$ by radionuclide, and $1.74{\pm}0.51$ by oxymetry. The overall correlation coefficient was 0.86(p<0.001), and Bland-Altman range of agreement encompassing 4SD was 1.05. For atrial septal defect, ventricular septal defect, patent ductus arteriosus, tricuspid and mitral insufficiency, the correlation coefficient was 0.78, 0.90, 0.84, 0.63 and 0.44, and Bland-Altman range was 1.51, 0.74, 0.96, 1.57, and 1.50, respectively. Conclusion: There is good agreement but wide variance between the Qp/Qs ratios by radionuclide method and oxymetry. Associated atrioventricular valvar insufficiency decreases the correlation coefficient and widens the variance. Wide overall variance suggests that Qp/Qs measurements by two techniques should not be used interchangeably.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.3096-3101
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• 2013

The study is to develop a tool to measure knowledge, attitude and behavior towards irradiated food derived from three factors of 20 items in regard to the knowledge of irradiated food. The variances in explanatory power for the first, second and third factors were 43.1%, 12.0% and 9.9% respectively, which marked a total of 65.0%. As to the attitude towards irradiated food, one factor was derived from 4 items and this factor, the result of measurement scale analysis, was named "the attitude towards irradiated food". The variance in the explanatory power of this factor was 71.1%. In regard to the behavior towards irradiated food, one factor was derived from 5 items and the variance in its explanatory power was measured to 57.6%, that is total 57.6% was explained.

• Journal of Korean Biological Nursing Science
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• v.19 no.4
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• pp.241-251
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• 2017

Purpose: This study aimed to examine the factors related to the bone mineral density (BMD) in male and female adults aged 50 years or older. The factors included were socio-demographics, body mass index (BMI), blood pressure, blood lipids, and health habits. Methods: As a secondary data analysis, this study used raw data from the 5th Korean National Health and Nutrition Examination Survey, and selected 2,295 adults aged over 50 years who participated in the survey and had BMD values. The T-score of the femoral neck was evaluated for BMD. Data were analyzed using descriptive statistics, ANOVA and multiple regression. Results: The factors influencing the BMD in men were age (${\beta}=-.029$, p<.001), BMI (${\beta}=.100$, p<.001), triglyceride (${\beta}=-.001$, p=.001), and calcium (${\beta}=.001$, p=.003), and the suggested regression equation explained 25.6% of the variance in BMD (F=16.32, p<.001). The factors related to BMD in women were age (${\beta}=-.060$, p<.001), BMI (${\beta}=.091$, p<.001), total cholesterol (${\beta}=-.002$, p=.028), HDL cholesterol (${\beta}=.009$, p=.001), and calcium (${\beta}=.001$, p=.004), and the suggested regression equation explained 47.0% of the variance in BMD (F=61.72, p<.001). Conclusion: Based on the findings of this study, the modifiable factors, such as BMI, blood cholesterol, and calcium, should be targeted to improve the BMD in both men and women.