• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.4
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• pp.1-20
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• 2023

This study attempted to identify the relationship between the investment determinants of accelerators and investment performance through empirical analysis. Through literature review, four dimensions and 12 measurement items were extracted for investment determinants, which are independent variables, and investment performance was adjusted to the cumulative amount of subsequent investment based on previous studies. Performance data from 594 companies selected by TIPS from 2017 to 2019, which are relatively reliable and easy to secure data, were collected, and the subsequent investment cumulative attraction amount, which is a dependent variable, was hypothesized through multiple regression analysis three years after the investment. As a result of the study, 'industrial experience years' in the characteristics of founders, 'market size', 'market growth', 'competitive strength', and 'number of patents' in the characteristics of products and services had a significant positive (+) effect. The impact of independent variables on dependent variables was most influenced by the competitive strength of market characteristics, followed by the number of years of industrial experience, the number of patents, the size of the market, and market growth. This was different from the results of previous studies conducted mainly on qualitative research methods, and in most previous studies, the characteristics of founders were the most important, but the empirical analysis results were market characteristics. As a sub-factor, the intensity of competition, which was the subordinate to the importance of previous studies, had the greatest influence in empirical analysis. The academic significance of this study is that it presented a specific methodology to collect and build 594 empirical samples in the absence of empirical research on accelerator investment determinants, and created an opportunity to expand the theoretical discussion of investment determinants through causal research. In practice, the information asymmetry and uncertainty of startups that accelerators have can help them make effective investment decisions by establishing a systematic model of experience-dependent investment determinants.

• Tuberculosis and Respiratory Diseases
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• v.64 no.6
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• pp.433-438
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• 2008

Background: Measurement of the maximum oxygen uptake in patients with chronic obstructive pulmonary disease (COPD) has been used to determine the intensity of exercise and to estimate the patient's response to treatment during pulmonary rehabilitation. However, cardiopulmonary exercise testing is not widely available in Korea. The 6-minute walk test (6MWT) is a simple method of measuring the exercise capacity of a patient. It also provides high reliability data and it reflects the fluctuation in one' s exercise capacity relatively well with using the standardized protocol. The prime objective of the present study is to develop a regression equation for estimating the peak oxygen uptake ($VO_2$) for men with moderate to very severe COPD from the results of a 6MWT. Methods: A total of 33 male patients with moderate to very severe COPD agreed to participate in this study. Pulmonary function testing, cardiopulmonary exercise testing and a 6MWT were performed on their first visits. The index of work ($6M_{work}$, 6-minute walk distance [6MWD]${\times}$body weight) was calculated for each patient. Those variables that were closely related to the peak $VO_2$ were identified through correlation analysis. With including such variables, the equation to predict the peak $VO_2$ was generated by the multiple linear regression method. Results: The peak $VO_2$ averaged $1,015{\pm}392ml/min$, and the mean 6MWD was $516{\pm}195$ meters. The $6M_{work}$ (r=.597) was better correlated to the peak $VO_2$ than the 6MWD (r=.415). The other variables highly correlated with the peak $VO_2$ were the $FEV_1$ (r=.742), DLco (r=.734) and FVC (r=.679). The derived prediction equation was $VO_2$ (ml/min)=($274.306{\times}FEV_1$)+($36.242{\times}DLco$)+($0.007{\times}6M_{work}$)-84.867. Conclusion: Under the circumstances when measurement of the peak $VO_2$ is not possible, we consider the 6MWT to be a simple alternative to measuring the peak $VO_2$. Of course, it is necessary to perform a trial on much larger scale to validate our prediction equation.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.736-745
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• 1998

Background: Respiratory muscle interaction is further profoundly affected by a number of pathologic conditions. Hyperinflation may be particularly severe in chronic obstructive pulmonary disease(COPD) patients, in whom the functional residual capacity(FRC) often exceeds predicted total lung capacity(TLC). Hyperinflation reduces the diaphragmatic effectiveness as a pressure generator and reduces diaphragmatic contribution to chest wall motion. Ultrasonography has recently been shown to be a sensitive and reproducible method of assessing diaphragmatic excursion. This study was performed to evaluate how differences of diaphragmatic excursion measured by ultrasonography associate with normal subjects and COPD patients. Methods: We measured diaphragmatic excursions with ultrasonography on 28 healthy subjects(l6 medical students, 12 age-matched control) and 17 COPD patients. Ultrasonographic measurements were performed during tidal breathing and maximal respiratory efforts approximating vital capacity breathing using Aloka KEC-620 with 3.5 MHz transducer. Measurements were taken in the supine posture. The ultrasonographic probe was positioned transversely in the midclavicular line below the right subcostal margin. After detecting the right hemidiaphragm in the B-mode the ultrasound beam was then positioned so that it was approximately parallel to the movement of middle or posterior third of right diaphragm. Recordings in the M-mode at this position were made throughout the test. Measurements of diaphragmatic excursion on M-mode tracing were calculated by the average gap in 3 times-respiration cycle. Pulmonary function test(SensorMedics 2800), maximal inspiratory(PImax) and expiratory mouth pressure(PEmax, Vitalopower KH-101, Chest) were measured in the seated posture. Results: During the tidal breathing, diaphragmatic excursions were recorded $1.5{\pm}0.5cm$, $1.7{\pm}0.5cm$ and $1.5{\pm}0.6cm$ in medical students, age-matched control group and COPD patients, respectively. Diaphragm excursions during maximal respiratory efforts were significantly decreased in COPD patients ($3.7{\pm}1.3cm$) when compared with medical students, age-matched control group($6.7{\pm}1.3cm$, $5.8{\pm}1.2cm$, p< 0.05}. During maximal respiratory efforts in control subjects, diaphragm excursions were correlated with $FEV_1$, FEVl/FVC, PEF, PIF, and height. In COPD patients, diaphragm excursions during maximal respiratory efforts were correlated with PEmax(maximal expiratory pressure), age, and %FVC. In multiple regression analysis, the combination of PEmax and age was an independent marker of diaphragm excursions during maximal respiratory efforts with COPD patients. Conclusion: COPD subjects had smaller diaphragmatic excursions during maximal respiratory efforts than control subjects. During maximal respiratory efforts in COPD patients, diaphragm excursions were well correlated with PEmax. These results suggest that diaphragm excursions during maximal respiratory efforts with COPD patients may be valuable at predicting the pulmonary function.

• Tuberculosis and Respiratory Diseases
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• v.56 no.6
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• pp.600-610
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• 2004

Background : The plasma B-type natriuretic peptide(BNP) concentration increases with the degree of pulmonary hypertension in patients with chronic respiratory disease. The aim of this study was to examine the prognostic role of BNP in the acute exacerbation of chronic obstructive lung disease (COPD). Method : We selected 67 patients who were admitted our hospital because of an acute exacerbation of COPD. Their BNP levels were checked on admission at the Emergency Department. Their medical records were analyzed retrospectively. The patients were divided into two groups according to their in-hospital mortality. The patients' medical history, comobidity, exacerbation type, blood gas analysis, pulmonary function, APACHE II severity score and plasma BNP level were compared. Results : Multiple logistic regression analysis identified three independent predictors of mortality: $FEV_1$, APACHE II score and plasma BNP level. The decedents group showed a lower $FEV_1$($28{\pm}7$ vs. $37{\pm}15%$, p=0.005), a higher APACHE II score($22.4{\pm}6.1$ vs. $15.8{\pm}4.7$, p=0.000) and a higher BNP level ($201{\pm}116$ vs. $77{\pm}80pg/mL$, p=0.000) than the sSurvivors group. When the BNP cut-off level was set to 88pg/mL using the receiver operating characteristic curve, the sensitivity was 90% and the specificity was 75% in differentiating between the survivors and decedents. On Fisher's exact test, the odds ratio for mortality was 21.2 (95% CI 2.49 to 180.4) in the patients with a BNP level > 88pg/mL. Conclusion : The plasma BNP level might be a predictor of mortality in an acute exacerbation of COPD as well as the $FEV_1$ and APACHE II score.

• Tuberculosis and Respiratory Diseases
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• v.60 no.5
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• pp.540-547
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• 2006

Background : Vital stability and right side heart failure are major prognostic factors of acute pulmonary thromboembolism. While it is important to recognize right side heart failure, it is often difficult in real practice. Recently, several studies have described early diagnostic tools for detecting right side heart failure including echocardiography and biochemical markers. This study, we evaluated the prognostic role of the B-type natriuretic peptide (BNP) in an acute pulmonary thromboembolism. Methods : Thirty-four patients with a diagnosis of acute pulmonary thromboembolism were enrolled in the study. The BNP levels were measured and echocardiography was performed at the Emergency Department. Data on the prognostic factors including ventilatory support, vital stability, pulmonary artery pressure, degree of tricuspid valve regurgitation, complications and death was collected from the patients' medical records. The patients with an acute pulmonary thromboembolism were divided into two groups based on the vital stability and the BNP level and the cutoff values and prognostic factors of the two groups were compared. Results : The predictors of the vital stability that influence the prognosis of patients with acute pulmonary thromboembolism were the BNP level, ventilatory support and death. The plasma BNP levels showed a strong correlation with the vital stability, ventilatory support, thrombolytic therapy and death. When the BNP cutoff level was set to 377.5 pg/dl in a ROC curve, the sensitivity and the specificity for differentiating between the groups with stable or unstable vital signs was 100% and 90%, respectively. Conclusion : This study indicates that a measurement of the plasma BNP levels may be a useful prognostic marker in patients with an acute pulmonary thrombo-embolism.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.23-33
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• 2016

The current smart lighting is shaped to offer the lighting environment suitable for current context, after identifying user's action and location through a sensor. The sensor-based context awareness technology just considers a single user, and the studies to interpret many users' various context occurrences and conflicts lack. In existing studies, a fuzzy theory and algorithm including ReBa have been used as the methodology to solve context conflict. The fuzzy theory and algorithm including ReBa just avoid an opportunity of context conflict that may occur by providing services by each area, after the spaces where users are located are classified into many areas. Therefore, they actually cannot be regarded as customized service type that can offer personal preference-based context conflict. This paper proposes a priority-based LED lighting control system interpreting multiple context conflicts, which decides services, based on the granted priority according to context type, when service conflict is faced with, due to simultaneous occurrence of various contexts to many users. This study classifies the residential environment into such five areas as living room, 'bed room, study room, kitchen and bath room, and the contexts that may occur within each area are defined as 20 contexts such as exercising, doing makeup, reading, dining and entering, targeting several users. The proposed system defines various contexts of users using an ontology-based model and gives service of user oriented lighting environment through rule based on standard and context reasoning engine. To solve the issue of various context conflicts among users in the same space and at the same time point, the context in which user concentration is required is set in the highest priority. Also, visual comfort is offered as the best alternative priority in the case of the same priority. In this manner, they are utilized as the criteria for service selection upon conflict occurrence.

• Clinical and Experimental Pediatrics
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• v.51 no.10
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• pp.1065-1070
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• 2008

Purpose : This study aims to determine whether early closure (within 7 d) of significant patent ductus arteriosus (PDA) with indomethacin or ligation reduces neonatal morbidity when compared with delayed closure (after 7 d). Methods : Fifty-eight extremely-low-birth-weight infants admitted to the NICU of Seoul National University Hospital from April 2005 to May 2007 with PDA were studied retrospectively. Results : The mean gestational age (GA) was $26{\pm}2weeks$ (range, 23-32 wk), and the birth weight was $782{\pm}146g$ (range, 430-990 g). The delayed closure group was associated with early GA ($25.7{\pm}1.7wk$ vs $27.1{\pm}2.0wk$, P=0.013), in vitro fertilization (IVF) (55% vs 24%, P=0.017), and the absence of preeclampsia (5% vs. 34%, P=0.013). There was no difference in ductal size between the early closure and delayed closure groups. The incidence of bronchopulmonary dysplasia (95% vs 65%, P=0.012) and intraventricular hemorrhage (70% vs. 39%, P=0.027) increased in the delayed closure group. Using regression analysis adjusted for gestational age, delayed closure correlated positively with the duration of ventilator support (P=0.008), hospitalization (P=0.020), time to full enteral feeding (P<0.001), and total parenteral nutrition (P=0.010). Conclusion : Delayed closure of the hemodynamically significant patent ductus arteriosus in extremely-low-birth-weight infants is significantly related to the development of various morbidities. Thus, early closure of PDA is needed within the first week of life.

• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.59-71
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• 2016

To investigate the sorption characteristics of Cs, which is one of the major isotopes of nuclear waste, on natural zeolite chabazite, XRD, EPMA, EC, pH, and ICP analysis were performed to obtain the informations on chemical composition, cation exchange capacity, sorption kinetics and isotherm of chabazite as well as competitive adsorption with other cations ($Li^+$, $Na^+$, $K^+$, $Rb^+$, $Sr^{2+}$). The chabazite used in this experiment has chemical composition of $Ca_{1.15}Na_{0.99}K_{1.20}Mg_{0.01}Ba_{0.16}Al_{4.79}Si_{7.21}O_{24}$ and its Si/Al ratio and cation exchange capacity (CEC) were 1.50 and 238.1 meq/100 g, respectively. Using the adsorption data at different times and concentrations, pseudo-second order and Freundlich isotherm equation were the most adequate ones for kinetic and isotherm models, indicating that there are multi sorption layers with more than two layers, and the sorption capacity was estimated by the derived constant from those equations. We also observed that equivalent molar fractions of Cs exchanged in chabazite were different depending on the ionic species from competitive ion exchange experiment. The selectivity sequence of Cs in chabazite with other cations in solution was in the order of $Na^+$, $Li^+$, $Sr^{2+}$, $K^+$ and $Rb^+$ which seems to be related to the hydrated diameters of those caions. When the exchange equilibrium relationship of Cs with other cations were plotted by Kielland plot, $Sr^{2+}$ showed the highest selectivity followed by $Na^+$, $Li^+$, $K^+$, $Rb^+$ and Cs showed positive values with all cations. Equilibrium constants from Kielland plot, which can explain thermodynamics and reaction kinetics for ionic exchange condition, suggest that chabazite has a higher preference for Cs in pores when it exists with $Sr^{2+}$ in solution, which is supposed to be due to the different hydration diameters of cations. Our rsults show that the high selectivity of Cs on chabazite can be used for the selective exchange of Cs in the water contaminated by radioactive nuclei.

• Tuberculosis and Respiratory Diseases
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• v.54 no.2
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• pp.210-218
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• 2003

Background : Sex specific cross sectional reference values for the lung function indices usually employ a linear model with a term for age and height. The purpose of this study was to determine the effects of the body mass index (BMI), the fat percentage of the body mass and the fat-free mass index (FFMI) on the forced expiratory volume curve. Methods : Between January 2000 and December 2001, a total of 300 subjects, 150 men and 150 women (mean age : $45{\pm}13$ years), with a normal lung function were enrolled in the study sample. This study measured the $FEV_1$, FVC and $FEF_{25-75%}$ from the forced expiratory volume curve by a spirometer and the body composition by a bioelectrical impedance method in all subjects. Multiple regression analysis was used in order to examine the effects of the body composition on the parameters derived from the forced expiratory volume curve. Results : After adjusting for age, the BMI and Fat percentage improved the descriptions of the FVC (p<0.05, $r^2=0.491$) and $FEV_1$ (p<0.05, $r^2=0.654$) in women. In contrast, the FFMI contributed significantly to the FVC (p<0.05, $r^2=0.432$) and $FEV_1$ (p<0.05, $r^2=0.567$) in men. The $FEF_{25-75%}$ correlated with the fat percentage in women (p<0.05, $r^2=0.337$). Conclusion : These results suggest that the BMI, the fat percentage and the FFMI are significant determinants of the forced expiratory volume curve. The plmonary function test, when considering the BMI, the fat percentage and the FFMI, might be useful in clinical applications.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.32-38
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• 2003

Objectives: The purpose of this study is to investigate the effects of stress and personality on sleep patterns, and further, to identify potential correlations between stress and personality characteristics. Methods: A total of 174 healthy college students were subjects for this study. Participants filled out the Daily Stress Inventory before sleep and the Modified Pittsburgh Sleep Quality Index after sleep on three consecutive days. They also filled out the 16 Personality Factor Questionnaire (16-PF), BDI (Beck Depression Inventory) and STAI (State-Trait Anxiety Inventory). Results: Minor stresses highly correlated with subjective sleep quality and symptoms of non-restorative sleep. However, total sleep time, sleep latency, awakening frequency, and frequency of dreams were not explained by stress scores. The O (guilty feeling), C (low ego strength) and Q4 (high anxiety) factors of the 16-PF also highly correlated with symptoms of non-restorative sleep and significantly affected sleep patterns. BDI and STAI scores also correlated with the above personality factors and minor stresses. Conclusion: This study showed that minor stresses impaired the restorative effects of sleep. Personality characteristics such as low ego strength, high levels of anxiety, and feelings of guilt were vulnerable to minor stresses. Minor stress, various personality characteristics, different coping patterns, and emotional response are highly correlated with each other and affect sleep patterns.