• Journal of Chest Surgery
• /
• v.41 no.6
• /
• pp.736-741
• /
• 2008

Background: Pneumonia continues to be the most common major infection in trauma patients. Despite the advances in prevention, diagnosis, and treatment for pneumonia, it remains a major cause of morbidity and mortality. The aim of this retrospective study is to identify the risk factors and clinical features of ventilator-associated pneumonia among chest trauma patients. Material and Method: The study population consisted of 78 mechanically ventilated patients admitted to the ICU of Chonnam National University Hospital between January, 2001, and December, 2006. The patients were divided into two groups: those with pneumonia (Group I) and without pneumonia (Group II). Clinical predictors of the occurrence and mortality for ventilator associated pneumonia were analyzed. Result: There were 57 men and 21 women, with a mean age of $48.3{\pm}19.9$ years. Almost half of the patients, 48.7% (38 of 78), had pneumonia. The mortality rate was 21.0% (8 of 38) in Group I and 2.5% (1 of 40) in Group II. The predictors of ventilator-associated pneumonia were the duration of mechanical ventilation (17.4 days vs 6.5 days, p<0.001), the mean stay in the ICU (21.7 days vs 9.7 days, p<0.001), the use of inotropics due to hemodynamic instability (63.1% vs 25.0%, p=0.001), and the serum level of CRP ($11.3{\pm}7.8$ vs $6.4{\pm}7.3$, p=0.006). Conclusion: Posttraumatic ventilator-associated pneumonia was significantly related with the duration of mechanical ventilation, the mean stay in ICU, and the use of inotropics due to hemodynamic instability. The serum level of CRP at admission was higher in the pneumonia group. Morbidity and mortality can be reduced by early identification of predictive factors for developing pneumonia in chest trauma patients.

• Journal of Intelligence and Information Systems
• /
• v.24 no.2
• /
• pp.1-19
• /
• 2018

Since stock movements forecasting is an important issue both academically and practically, studies related to stock price prediction have been actively conducted. The stock price forecasting research is classified into structured data and unstructured data, and it is divided into technical analysis, fundamental analysis and media effect analysis in detail. In the big data era, research on stock price prediction combining big data is actively underway. Based on a large number of data, stock prediction research mainly focuses on machine learning techniques. Especially, research methods that combine the effects of media are attracting attention recently, among which researches that analyze online news and utilize online news to forecast stock prices are becoming main. Previous studies predicting stock prices through online news are mostly sentiment analysis of news, making different corpus for each company, and making a dictionary that predicts stock prices by recording responses according to the past stock price. Therefore, existing studies have examined the impact of online news on individual companies. For example, stock movements of Samsung Electronics are predicted with only online news of Samsung Electronics. In addition, a method of considering influences among highly relevant companies has also been studied recently. For example, stock movements of Samsung Electronics are predicted with news of Samsung Electronics and a highly related company like LG Electronics.These previous studies examine the effects of news of industrial sector with homogeneity on the individual company. In the previous studies, homogeneous industries are classified according to the Global Industrial Classification Standard. In other words, the existing studies were analyzed under the assumption that industries divided into Global Industrial Classification Standard have homogeneity. However, existing studies have limitations in that they do not take into account influential companies with high relevance or reflect the existence of heterogeneity within the same Global Industrial Classification Standard sectors. As a result of our examining the various sectors, it can be seen that there are sectors that show the industrial sectors are not a homogeneous group. To overcome these limitations of existing studies that do not reflect heterogeneity, our study suggests a methodology that reflects the heterogeneous effects of the industrial sector that affect the stock price by applying k-means clustering. Multiple Kernel Learning is mainly used to integrate data with various characteristics. Multiple Kernel Learning has several kernels, each of which receives and predicts different data. To incorporate effects of target firm and its relevant firms simultaneously, we used Multiple Kernel Learning. Each kernel was assigned to predict stock prices with variables of financial news of the industrial group divided by the target firm, K-means cluster analysis. In order to prove that the suggested methodology is appropriate, experiments were conducted through three years of online news and stock prices. The results of this study are as follows. (1) We confirmed that the information of the industrial sectors related to target company also contains meaningful information to predict stock movements of target company and confirmed that machine learning algorithm has better predictive power when considering the news of the relevant companies and target company's news together. (2) It is important to predict stock movements with varying number of clusters according to the level of homogeneity in the industrial sector. In other words, when stock prices are homogeneous in industrial sectors, it is important to use relational effect at the level of industry group without analyzing clusters or to use it in small number of clusters. When the stock price is heterogeneous in industry group, it is important to cluster them into groups. This study has a contribution that we testified firms classified as Global Industrial Classification Standard have heterogeneity and suggested it is necessary to define the relevance through machine learning and statistical analysis methodology rather than simply defining it in the Global Industrial Classification Standard. It has also contribution that we proved the efficiency of the prediction model reflecting heterogeneity.

• Journal of the Ergonomics Society of Korea
• /
• v.36 no.3
• /
• pp.183-196
• /
• 2017

Objective: The purpose of this research was to assess the agreement between job physical risk factor analysis by ergonomists using ergonomic methods and physical examinations made by occupational physicians on the presence of musculoskeletal disorders of the upper extremities. Background: Ergonomics is the systematic application of principles concerned with the design of devices and working conditions for enhancing human capabilities and optimizing working and living conditions. Proper ergonomic design is necessary to prevent injuries and physical and emotional stress. The major types of ergonomic injuries and incidents are cumulative trauma disorders (CTDs), acute strains, sprains, and system failures. Minimization of use of excessive force and awkward postures can help to prevent such injuries Method: Initial data were collected as part of a larger study by the University of Utah Ergonomics and Safety program field data collection teams and medical data collection teams from the Rocky Mountain Center for Occupational and Environmental Health (RMCOEH). Subjects included 173 male and female workers, 83 at Beehive Clothing (a clothing plant), 74 at Autoliv (a plant making air bags for vehicles), and 16 at Deseret Meat (a meat-processing plant). Posture and effort levels were analyzed using a software program developed at the University of Utah (Utah Ergonomic Analysis Tool). The Ergonomic Epicondylitis Model (EEM) was developed to assess the risk of epicondylitis from observable job physical factors. The model considers five job risk factors: (1) intensity of exertion, (2) forearm rotation, (3) wrist posture, (4) elbow compression, and (5) speed of work. Qualitative ratings of these physical factors were determined during video analysis. Personal variables were also investigated to study their relationship with epicondylitis. Logistic regression models were used to determine the association between risk factors and symptoms of epicondyle pain. Results: Results of this study indicate that gender, smoking status, and BMI do have an effect on the risk of epicondylitis but there is not a statistically significant relationship between EEM and epicondylitis. Conclusion: This research studied the relationship between an Ergonomic Epicondylitis Model (EEM) and the occurrence of epicondylitis. The model was not predictive for epicondylitis. However, it is clear that epicondylitis was associated with some individual risk factors such as smoking status, gender, and BMI. Based on the results, future research may discover risk factors that seem to increase the risk of epicondylitis. Application: Although this research used a combination of questionnaire, ergonomic job analysis, and medical job analysis to specifically verify risk factors related to epicondylitis, there are limitations. This research did not have a very large sample size because only 173 subjects were available for this study. Also, it was conducted in only 3 facilities, a plant making air bags for vehicles, a meat-processing plant, and a clothing plant in Utah. If working conditions in other kinds of facilities are considered, results may improve. Therefore, future research should perform analysis with additional subjects in different kinds of facilities. Repetition and duration of a task were not considered as risk factors in this research. These two factors could be associated with epicondylitis so it could be important to include these factors in future research. Psychosocial data and workplace conditions (e.g., low temperature) were also noted during data collection, and could be used to further study the prevalence of epicondylitis. Univariate analysis methods could be used for each variable of EEM. This research was performed using multivariate analysis. Therefore, it was difficult to recognize the different effect of each variable. Basically, the difference between univariate and multivariate analysis is that univariate analysis deals with one predictor variable at a time, whereas multivariate analysis deals with multiple predictor variables combined in a predetermined manner. The univariate analysis could show how each variable is associated with epicondyle pain. This may allow more appropriate weighting factors to be determined and therefore improve the performance of the EEM.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.11 no.2
• /
• pp.130-136
• /
• 2008

Purpose: Lamivudine is known to be effective for the treatment of chronic hepatitis B in adults. However, data on lamivudine therapy in pediatrics is limited. The aim of this study was to evaluate the efficacy and durability of lamivudine therapy for chronic hepatitis B in Korean children. Methods: A total of 44 children (27 males and 17 females, ages 6 months to 14.8 years, mean age 6.7 years) with chronic hepatitis B who received lamivudine (3 mg/kg/day, max 100 mg) for at least 12 months were enrolled. We evaluated the serum AST, ALT and serological HBV markers (HBsAg and anti-HBs, HBeAg and anti HBe, and HBV DNA) periodically. Predictive three year cumulative seroconversion rates were obtained using the Kaplan-Meier method. Results: Twenty one (48%) of 44 children achieved seroconversion of HBeAg by three years, while 23 (42%) children did not. HBV DNA was cleared in 34 (77%) children and the serum ALT levels were normalized in 41 children (93%). The three year cumulative seroconversion rates were 60% for HBeAg, and the clearance rates were 76% for HBV DNA. Eighteen children who discontinued lamivudine after HBeAg seroconversion maintained the therapeutic response for three years (treatment duration 13~58 months mean 24 months). Viral breakthrough developed in 12 children (27%) during the therapy and the YMDD mutation was documented in 11 children (25%). The mean duration for the development of a mutation was 22.7 months. Loss of HBsAg occurred in 6 children (14%). The pretreatment ALT levels were higher in responders; however, the differences were not statistically significant (p>0.05). Conclusion: The results of this study showed that lamivudine treatment had a favorable effect and durable therapeutic response in children with chronic hepatitis B. Long term follow-up and alternative therapy are warranted for those patients who do not respond to this treatment.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.21 no.4
• /
• pp.206-216
• /
• 1988

In order to set up a predictive model for effective spat collection of pen shell, Atrina (Servatrina) pectinata, the survival rate and time required at each developmental stage of drifting larvae were surveyed during the period from June 8 to October 16 in 1986 at the Yongku inlet Chilchon Is., Chinhae Bay, the southern part of Korea. And also the experiments of spat collection were carried out In Yongku inlet during the period from July 6 to November 23 in 1987 and In Yoja Bay during the period from July 9 in 1987 to February 15 in 1588. The advent of D-shape larvae ca. $135\times144um $ long had three peaks in that area: August 1, 12 and 25. Umbo shape larvae ca. $300\times317um$ and full grown larvae ca. $455\times450um$ long also sowed three peaks: August 9, August 22 and September 4 for the former, and August 23, September 3 and September 16 for the latter. Nine to ten days was required for D-shape larvae to develop to umbo shape larvae. The instantaneous survival rate was 0.94 with a total survival rate if $54\%$ at this intermorphological stage. The required time of umbo to full grown larvae varied from twelve to fourteen days with a instantaneous survival rate of 0.88 and total survival rate of $19\%$. Twenty-two to twenty-three days was required for each group of the D-shape larvae to reach a fullgrown stage, and their total survival rate was $10\%$ during this developmental period. The number of the spat attached to the spat collector is 0.16 inds. per $m^2$ vertical spat collector in Yongku inlet and 0.48 inds. per $m^2$ horizontal spat collector in Yoja Bay. The average shell length of spat attached was $0.51({\pm}0.15)\;mm$ on September $27,\;38.52({\pm}6.98)\;mm$ on November 21 in 1987 and $49.00({\pm}10.77)mm$ on February 15 in 1988.

• Journal of Chest Surgery
• /
• v.40 no.3 s.272
• /
• pp.215-219
• /
• 2007

Background: Due to the advancement of video assisted thoracoscopic techniques, an operation for primary spontaneous pneumothorax is now considered a common procedure. However, whether a preventive operation is necessary when a contralateral bulla is found on High Resolution Computed Tomography (HRCT) at the time of the first primary spontaneous pneumothorax attack is still unknown. In this retrospective study, it was our intension to find whether contralateral bullae are related to the occurrence of pneumothorax. Material and Method: Between January 1999 and April 2006, 550 patients were admitted to the Chungnam University hospital with primary spontaneous pneumothorax, which was confirmed by the HRCT scans in 190 patents. In these 190 patients, 159 had not received a bilateral operation after their first primary spontaneous pneumothorax attack. In these 159 patients, the relationship between the presence of contralateral bullae and the occurrence of pneumothorax was measured. Result: In these 159 patients, 67 had contralateral bullae confirmed inform the HRCT scan, and 92 had no visible contralateral bullae, During the follow up period, 6 patients (8.9%) with contralateral bullae had an occurrence of contralateral pneumothorax, and 5 patients (5.4%) without contralateral bullae had an occurrence of contralateral pneumothorax. (p=0.529 [Fisher's exact test]) Conclusion: In patients with unilateral primary pneumothorax, an HRCT scan is a useful way of confirming contralateral pulmonary bullae. However, the presence of bullae is not a significant predictive sign of an occurrence of contralateral pneumothorax. Also, surgery for pneumothorax is not completely uncomplicated, and bilateral surgery is still doubtful. A further prospective study will be required to find the relationship between the bullae found on HRCT and the occurrence of pneumothorax.

• Tuberculosis and Respiratory Diseases
• /
• v.48 no.4
• /
• pp.522-529
• /
• 2000

Backgrounds : Assessment of the presence and degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. The measurement of peak expiratory flow(PEF) is a simple, fast, and cheap method to assess the severity of obstruction and its degree of reversibility. Assessing the reversibility of airflow obstruction by peak expiratory flow(PEF) measurements is practicable in general practice, but its usefulness has not been well investigated. We compared PEF and $FEV_1$ in assessing reversibility of airflow obstruction in patients with chronic obstructive pulmonary disease or asthma and developed a practical criterion for assessing the presence of reversibility in general practice. Methods : PEF measurements were performed (Spirometry) in 80 patients(aged 24-78) with a history of asthma or chronic obstructive lung disease before and after the inhalation of 200 g salbutamol. The change in PEF was compared with the change in forced expiratory volume in one second($FEV_1$). Reversible airflow obstruction was analyzed according to American Thoracic Society(ATS) criteria. Results : A 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ reversibility were observed in 45%(36) of the patients. Relative operating characteristic(ROC) analysis showed that an absolute improvement in PEF of 30 l/min gave optimal discrimination between patients with reversible and irreversible airflow obstruction(the sensitivity and specificity of an increase of 30 l/min in detecting a 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ were 72.2% and 72.7% respectively, with a positive predictive value of 68.4%). Conclusions : Absolute changes in PEF can be used to diagnose reversible airflow obstruction.

• Tuberculosis and Respiratory Diseases
• /
• v.50 no.2
• /
• pp.196-204
• /
• 2001

Background : Bronchial asthma is characterized by a reversible airway obstruction, airway hyperresponsiveness, and eosinophilic airway inflammation. The bronchodilator response(BDR) after short acting beta agonist inhalation and PC20 with methacholine inhalation are frequently used for diagnosing bronchial asthma. However, the relationship between the presence of a bronchodilator response and the degree of airway hyperresponsiveness is uncertain. Therefore, the availability of a eosinophil cationic protein (ECP) and a correlation ECP with a bronchodilator response and airway hyperresponsiveness was investigated. Method : A total 71 patients with a moderate to severe degree of bronchial asthma were enrolled and divided into two groups. 31 patients with a positive bronchodilator response and 38 patients with a negative bronchodilator response were evaluated. In both groups, the serum ECP, peripheral blood eosinophil counts, and total IgE level were measured and the methacholine bronchial provocation test was examined. Results : There were no differences observed in age, sex, atopy, and baseline spirometry in both groups. The peripheral eosinophil counts showed no difference in both groups, but the ECP level in group 1 (bronchodilator responder group) was higher than in group 2(non-bronchodilator responder group) ($22.4{\pm}20.7$ vs $14.2{\pm}10.4$, mean$\pm$SD). The PC20 in group 1 was significantly lower than in group 2 ($1.14{\pm}1.68$ vs $66{\pm}2.98$). There was a significant positive correlation between the BDR and ECP, and a negative correlation between the bronchial hyperresponsiveness and ECP. Conclusion : The bronchodilator response significantly correlated with the bronchial hyperresponsiveness and serum ECP in the moderate to severe asthma patients. Hence, the positive bronchodilator response is probably related with active bronchial inflammation and may be used as a valuable index in treatment, course and prognosis of bronchial asthma.

• Journal of Korean Ophthalmic Optics Society
• /
• v.11 no.1
• /
• pp.27-34
• /
• 2006

We investigated the question whether the efficacy of cleaning tear components on RGP lens and preserving the superior wettability of RGP lens depended on the different type of contact lens care system - RGP lens care solution, SCL care solution, combined solution both for SCL and RGP lens or saline solution. The removal efficacy of the deposited protein was examined by Lowry protein assay and Scanning Electro Microscope(SEM) and residual lipid concentration on RGP lens was determined by High Pressure Liquid Chromatology(HPLC). Wettability was assessed with an equilibrium water-in-air contact angle method. When cared by RGP lens solution, it was demonstrated that 62 percent out of the adhered protein on RGP lens were removed and the removal efficacy of RGP lens solution was not only 4 times than saline solution and the alternative but also higher twice than SCL solution. Contrarily, the SCL solution had the most excellent removal efficacy of the adhered protein on SCL. These results suggest that the cleaning efficacy is thought to be affected by the other factors like the viscosity of care solutions, which mutual contact between RGP lens and care solutions is on the increase due to the viscosity enhancer in RGP lens care solution. RGP lens solution had the greatest removing efficacy to cholesterol and the residual cholesterol concentration was decreased to 50%. It is significant for RGP lens to preserve the superior wettability which means the predictive value for comfortable wearing and it showed that the RGP lens solution offered the most excellent efficacy to maintain the surface wettability. Combined solution both for SCL and RGP lens had weak efficacy of cleaning and maintaining wettability for RGP lens compared to RGP lens care solution.

• Tuberculosis and Respiratory Diseases
• /
• v.43 no.3
• /
• pp.377-387
• /
• 1996

Background : In 1980, WHO made a definition in which the term "impairment" as applied to the respiratory system is used to describe loss of lung function, "disability" the resulting diminution in exercise capacity. The measurement of pulmonary function during exercise would give us information about overall functional capacity and respiratory performance that would be lacking in tests performed at rest. We conducted this study to investigate the role of resting pulmonary function test and exercise test for assessing impairment/disability in patients with chronic airflow obstruction(CAO). Method : We studied 19 patients with CAO. The spirometry and body plethysmograph were performed in stable condition. And then patients performed a progressive incremental exercise test to a symptom-limited maximum using cycle ergometer. Patients were divided in two groups, severe and non-severe impairment, according to the resting PFTs and compaired each other. A patient was considered to be severely impaired if FVC < 50 %, FEV1 < 40 % or FEV1/FVC < 40 %. Results : 1) The airway obstruction and hypoxemia of severe impairment group were more severe and exercise performance was markedly reduced compairing to non-severe impairment group. 2) The severe impairment group showed ventilatory limitation during exercise test and the limiting symptomes ware dyspnea in 9/10 patients. 3) The impairment and disability of the patients with tuberculous destructed lung were most marked in patients with CAO. 4) The FEV1 was the most prevalent criterion for the determination of severe impairment based on resting PFTs and was the valuable best correlated to V02max(r=0.81, p < 0.001). 5) The sensitivity of exercise limits for predicting severe disability according to resting PFTs was 80 % and specificity 89 %. Conclusion : In patients with severe CAO, FEV1 is a good predictive of exercise performance and impairment measured by resting PFTs can predict a disability by exercise test.