• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.6
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• pp.39-50
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• 2022

Based on the signaling theory, this study examined whether startups are more likely to attract venture investment when receiving government R&D subsidies. First, we reviewed previous studies of the investment decision-making process of venture capitalists and understood the conditions that influence investment decisions. Based on previous studies on the signal effect of government subsidies, particularly government R&D grants, on inducing private fund investment, this study revealed a mechanism to induce venture investment by startups. In addition, in order to verify whether government R&D subsidies have the effect of inducing venture investment, an empirical analysis was conducted based on data from startups under seven years and certified as a venture companies in 2021. This paper used PSM(Propensity Score Matching) method and DID(Difference In Difference) analysis for an empirical study to analyze the average treatment effect on the treated group(beneficiary startups of government R&D grants). As a result of empirical analysis, companies that receive more government R&D subsidies after starting a business are more likely to attract venture investment. From two to three years after conducting the first government R&D project, startups that received government R&D grants attracted more venture investment than those that did not. The results of this paper demonstrate that government R&D projects can also affect the venture investment ecosystem, giving policy implications to government R&D projects targeting startups. It is also expected to suggest strategic implications to startups that need new funding.

• Korean Journal of Radiology
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• v.24 no.9
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• pp.860-870
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• 2023

Objective: The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state water-excitation sequence magnetic resonance imaging (3D-DESS-WE-MRI). However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored. We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI. Materials and Methods: This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors. Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients. FN visibility and tumor location relative to FN on 3D-DESS-WE-MRI were evaluated in 120 patients. Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors. Results: The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESS-WE-MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively. The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases. Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64-8.25] and 2.02 [95% CI: 0.32-12.90], respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19-16.75] and 1.94 [95% CI: 0.20-18.49], respectively). Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001). Conclusion: Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy. This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates.

• Journal of the Korean School Mathematics Society
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• v.19 no.2
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• pp.123-151
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• 2016

The purpose of this study is to analyze the existing studies about the effect on private tutoring and EBS broadcasting which is considered as the alternative which was presented by education authorities. And this study attempts to measure the degree of the effects of private tutoring and EBS engagement on mathematics achievement using various quantitative methodologies. T-test and OLS multiple regression indicates some selection-bias which has positive direction compared to the PSM method closed to experimental design. So, it will be required to consider the methodology which measures the exact effect of institution or participation when we conduct the observational studies.

• Journal of Labour Economics
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• v.42 no.2
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• pp.37-62
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• 2019

We investigate the type of self-selection arising in college transfer in Korea, and then estimate the returns to additional college education gained through transfers from junior colleges to four-year colleges or universities. In this paper, we show that academic transfer is consistent with a positive selection hypothesis, in a sense that students with characteristics correlated positively to productivity are more likely to transfer to four-year colleges from junior colleges. These empirical results also meet an underlying dispersion condition. In addition, we find that the transferred would make a statistically significant return to additional college education.

• Journal of Korean Critical Care Nursing
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• v.16 no.3
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• pp.24-33
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• 2023

Purpose : This study aims to establish an optimal cut-off score on the Braden scale for the assessment of pressure injury to detect pressure injury risks among inpatients in a South Korean tertiary hospital. Methods : This retrospective study used electronic medical records, from January to December 2022. A total of 654 patients were included in the study. Of these, 218 inpatients with pressure injuries and 436 without pressure injuries were classified and analyzed using 1:2 Propensity Score Matching (PSM), and the generalized estimating equation was performed using SPSS Version 26 and the R Machlt package program. Results : The cut-off value on the Braden scale for distinguishing pressure injury was 17 points, and the AUC (area under the ROC curve) was 0.531 (0.484-0.579). The sensitivity was 56.6% (45.5-67.7%) and the specificity was 69.7% (66.0-73.4%). With 17 points, the Braden scale cut-off distinguished those who had pressure injuries from those who did not at the time of admission (p < .03). In the pressure injury group, the Braden score on the day of the pressure injury was 14, with significant results in all subcategories except the moisture category. Conclusion : Our findings revealed that a cut-off value of 17 was optimal for predicting the risk of pressure injuries among tertiary hospital inpatients. Future studies should evaluate the optimal cut-off values in different clinical environments. Additionally, it is necessary to conduct multicenter large sample studies to verify the effectiveness of a 17 value in PI risk assessments.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.523-531
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• 2016

This paper studies the empirical relationship between various privacy protection measures and personal information invasion experience of firms and individuals using rich and heterogeneous survey data. By analyzing PSM models. we get the following results: first, the treatment group which have more technical measures and/or IS investment tends to experience more privacy invasion than the control group which have less of them. second, the reverse causality, that is firms and individuals with more experience of privacy invasion tends to take more measure for personal information protection, is found to exist. From these result, we discuss proper privacy policies implications in respects of attackers benefits and individual irrationality.

• Journal of Korea Technology Innovation Society
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• v.21 no.2
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• pp.738-766
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• 2018

The purpose of this paper is to figures out the impact on the business performance based on the case studies about the establishment of automated smart factories supported by the government. In this study, the effectiveness of supporting business is verified by comparing supported company with non-supported ones using methods such as T-test and ANOVA. The PSM method was used to solve the selection bias issue between the experimental group and the controlled group. The research results have shown that the effect of the supporting business to the automated system was tenuous, and the amount of sales and research and development costs was increased after a certain schedule passed in case of the supporting project to the smart factory. There is some time lag to appear the effect of the government supporting businesses and the supporting business to the automated system leads to long term sales increase by increasing parameters like research and development costs rather than direct influence. Therefore, this research will be useful information for the process of establishing useful basic data and policies which helps to secure new budget Government Supporting Businesses and find ways improve the business.

• Journal of Gastric Cancer
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• v.19 no.4
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• pp.438-450
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• 2019

Purpose: Although linear-shaped gastroduodenostomy (LSGD) was reported to be a feasible and reliable method of Billroth I anastomosis in patients undergoing totally laparoscopic distal gastrectomy (TLDG), the feasibility of LSGD for patients undergoing totally robotic distal gastrectomy (TRDG) has not been determined. This study compared the feasibility of LSGD in patients undergoing TRDG and TLDG. Materials and Methods: All c: onsecutive patients who underwent LSGD after distal gastrectomy for gastric cancer between January 2009 and December 2017 were analyzed retrospectively. Propensity score matching (PSM) analysis was performed to reduce the selection bias between TRDG and TLDG. Short-term outcomes, functional outcomes, learning curve, and risk factors for postoperative complications were analyzed. Results: This analysis included 414 patients, of whom 275 underwent laparoscopy and 139 underwent robotic surgery. PSM analysis showed that operation time was significantly longer (163.5 vs. 132.1 minutes, P<0.001) and postoperative hospital stay significantly shorter (6.2 vs. 7.5 days, P<0.003) in patients who underwent TRDG than in patients who underwent TLDG. Operation time was the independent risk factor for LSGD after intracorporeal gastroduodenostomy. Cumulative sum analysis showed no definitive turning point in the TRDG learning curve. Long-term endoscopic findings revealed similar results in the two groups, but bile reflux at 5 years showed significantly better improvement in the TLDG group than in the TRDG group (P=0.016). Conclusions: LSGD is feasible in TRDG, with short-term and long-term outcomes comparable to that in TLDG. LSGD may be a good option for intracorporeal Billroth I anastomosis in patients undergoing TRDG.

• The Journal of Korean Medicine
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• v.40 no.3
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• pp.1-20
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• 2019

Objectives: This study aims to investigate the effects of Korean Medicine Hospital Utilization (KMHU) on major adverse cardiovascular events (MACE), myocardial infarction (MI), stroke, and death in hypertensive patients taking antihypertensives. Methods: Using the Korean National Health Insurance Service-National Sample Cohort database, this study identified and diagnosed 68,457 hypertensive patients taking antihypertensives between 2003 and 2006. They were divided into KMHU and non-KMHU groups. The follow-up period ended with the diagnosis of myocardial infarction, stroke, or death. After propensity score matching (PSM), there were 18,242 patients each in the non-KMHU and KMHU groups. We calculated the incidence rate, hazard ratio (HR), and 95% confidence interval (CI) for MACE, myocardial infarction, stroke, and death in patients with hypertension using a stratified Cox proportional hazard model. In addition, secondary outcome analyses for stroke and cardiovascular mortality were performed. Results: After PSM, the HRs for MACE (HR: 0.84, 95% CI: 0.81-0.87), all-cause mortality (HR: 0.75, 95% CI: 0.72-0.79), and myocardial infarction (HR: 0.90, 95% CI: 0.83-0.97) were significantly lower in the KMHU group than in the non-KMHU group. Moreover, the HRs for stroke-related mortality, haemorrhage and ischaemic stroke-related mortality, and ischaemic heart disease-related and circulatory system disease-related mortality were significantly lower in the KMHU group than in the non-KMHU group. Conclusions: On long-term follow-up observation, this study supported the effect of KMHU for managing hypertension and reducing the burden of cardiovascular diseases.

• Journal of Society of Preventive Korean Medicine
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• v.25 no.3
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• pp.25-37
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• 2021

Objectives : To investigate the effectiveness of Korean Medicine services use on the all-cause mortality and incidence of Parkinson's disease(PD) in elderly patients with chronic disease based on the National Health Insurance Service Corhort Database (elderly), called as the NHIS-senior. Methods : This study was a retrospective cohort analysis conducted using the NHIS-senior. Patients with chronic diseases over 65 years old who were not diagnosed PD during 2007-2009 were identified. The case group was defined as patients who used both Korean Medicine and Western Medicine services and the control group consisted of patients who used Western Medicine service only. The all-cause mortality and incidence of PD was analyzed using the Cox proportional hazard model after a propensity score matching(PSM) with a 1:1 ratio. Results : After PSM, the cohort included 47,546 subjects (23,773 in the case group, 23,773 in the control group). Sex, age, comorbidity, severity of disability, and neurology medical service utilization were adjusted in both groups. The mortality was 0.668 times (95% C.I.: 0.646-0.690) lower in the case group than the control group, which was statistically significant (p<0.001). The incidence of PD was 1.051 times (95% C.I.: 0.962-1.148) higher in the case group than the control group, which was not statistically significant(p=0.272). Conclusion : It was not obvious that the use of both Korean Medicine service and Western Medicine services for prevention of PD is benefitial than using only Western Medicine. But it would be possible that using both Korean Medicine and Western Medicine services decreases the mortality than using Western Medicine alone.