• Journal of Intelligence and Information Systems
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• v.26 no.2
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• pp.131-145
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• 2020

In line with the trend of industrial innovation, IoT technology utilized in a variety of fields is emerging as a key element in creation of new business models and the provision of user-friendly services through the combination of big data. The accumulated data from devices with the Internet-of-Things (IoT) is being used in many ways to build a convenience-based smart system as it can provide customized intelligent systems through user environment and pattern analysis. Recently, it has been applied to innovation in the public domain and has been using it for smart city and smart transportation, such as solving traffic and crime problems using CCTV. In particular, it is necessary to comprehensively consider the easiness of securing real-time service data and the stability of security when planning underground services or establishing movement amount control information system to enhance citizens' or commuters' convenience in circumstances with the congestion of public transportation such as subways, urban railways, etc. However, previous studies that utilize image data have limitations in reducing the performance of object detection under private issue and abnormal conditions. The IoT device-based sensor data used in this study is free from private issue because it does not require identification for individuals, and can be effectively utilized to build intelligent public services for unspecified people. Especially, sensor data stored by the IoT device need not be identified to an individual, and can be effectively utilized for constructing intelligent public services for many and unspecified people as data free form private issue. We utilize the IoT-based infrared sensor devices for an intelligent pedestrian tracking system in metro service which many people use on a daily basis and temperature data measured by sensors are therein transmitted in real time. The experimental environment for collecting data detected in real time from sensors was established for the equally-spaced midpoints of 4×4 upper parts in the ceiling of subway entrances where the actual movement amount of passengers is high, and it measured the temperature change for objects entering and leaving the detection spots. The measured data have gone through a preprocessing in which the reference values for 16 different areas are set and the difference values between the temperatures in 16 distinct areas and their reference values per unit of time are calculated. This corresponds to the methodology that maximizes movement within the detection area. In addition, the size of the data was increased by 10 times in order to more sensitively reflect the difference in temperature by area. For example, if the temperature data collected from the sensor at a given time were 28.5℃, the data analysis was conducted by changing the value to 285. As above, the data collected from sensors have the characteristics of time series data and image data with 4×4 resolution. Reflecting the characteristics of the measured, preprocessed data, we finally propose a hybrid algorithm that combines CNN in superior performance for image classification and LSTM, especially suitable for analyzing time series data, as referred to CNN-LSTM (Convolutional Neural Network-Long Short Term Memory). In the study, the CNN-LSTM algorithm is used to predict the number of passing persons in one of 4×4 detection areas. We verified the validation of the proposed model by taking performance comparison with other artificial intelligence algorithms such as Multi-Layer Perceptron (MLP), Long Short Term Memory (LSTM) and RNN-LSTM (Recurrent Neural Network-Long Short Term Memory). As a result of the experiment, proposed CNN-LSTM hybrid model compared to MLP, LSTM and RNN-LSTM has the best predictive performance. By utilizing the proposed devices and models, it is expected various metro services will be provided with no illegal issue about the personal information such as real-time monitoring of public transport facilities and emergency situation response services on the basis of congestion. However, the data have been collected by selecting one side of the entrances as the subject of analysis, and the data collected for a short period of time have been applied to the prediction. There exists the limitation that the verification of application in other environments needs to be carried out. In the future, it is expected that more reliability will be provided for the proposed model if experimental data is sufficiently collected in various environments or if learning data is further configured by measuring data in other sensors.

• Clinical and Experimental Pediatrics
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• v.48 no.4
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• pp.416-424
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• 2005

Purpose : To find the risk factors associated with coronory artery lesions, non-responsiveness to intravenous immunoglobulin(IVIG) treatment, and recurrences in Kawasaki disease patients. Methods : We retrospectively analyzed 1,000 Kawasaki disease patients who were admitted to Yonsei University Medical Center from September 1990 to December 2003. We compared between responder and non-responder groups to IVIG treatment as well as between relapsed and non-relapsed groups, and as to the relapsed group, we also compared variables between patients in their first and second attack states. Finally, factors associated with longer-fever duration from disease onset were evaluated. Results : Longer fever durations before and after IVIG treatment, male sex, lower Hgb and Hct level, higher WBC count and segmented WBC proportion, and higher CRP and Harada's score were related with coronary artery lesions. Non-responsiveness was related to higher WBC count, segmented WBC proportion, CRP, SGPT, Harada's score, and pyuria. Moderate-to-severe coronary artery dilatations and recurrences were more commonly seen among the non-responder group. No significant predictive factors for recurrence were found. In the relapsed group, lower WBC count, CRP, and shorter fever duration from disease onset were observed in their second attack state. Fever duration from disease onset showed positive correlation with WBC count, CRP, and Harada's score and negative correlation with Hgb levels. Conclusion : Higher WBC count, CRP, and higher Harada's score were related to both higher incidences of coronary artery lesions and non-responsiveness to IVIG treatment, and these factors were also related with longer fever duration. Non-responders to IVIG treatment showed higher recurrence rate and more moderate-to-severe coronary artery dilatations than responders.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.899-906
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• 1997

Background : The percutaneous pleural needle biopsy have been regarded as cornerstone in the diagnosis of lymphocyte dominant pleural effusions of which acid fast bacilli smear and cytologic exam was negative. However, the complications of percutaneous pleural needle biopsy is not rare and its diagnostic efficacy is not always satisfactory. Recently, pleural fluid adenosine deaminase (ADA) and carcinoembryonic antigen (CEA) are widely accepted as markers of tuberculous pleurisy and malignant pleural effusion respectively. We designed this study to re-evaluate the role of percutaneous pleural needle biopsy in the diagnosis of lymphocyte dominant exudative pleural effusions whose AFB smear, cytologic exam was negative. Method : Retrospective analysis of 73 cases of percutaneous pleural needle biopsy in case of lymphocyte dominant exudative pleural effusions whose AFB smear and cytoloic exam was negative from Jan 1994 to Feb 1996 was done. Result : In 35 cases, specific diagnosis was obtained(all cases were tuberculous pleurisy), and in 30 cases specific diagnosis was not obtained in spite of getting adequate pleural tissues, and in the other 8 cases, percutaneous pleural biopsy failed to get pleural tissues. In 9 cases, complications were combined including pneuomothorax and hemothorax. All 49 cases of pleural effusions whose ADA value was higher than 40IU/L and satisfying other categories were finally diagnosed as tuberculous pleurisy, however, the pleural biopsy confirmed only 28 cases as tuberculous pleurisy. In 6 cases of pleural effusions of which CEA value is higher than 10ng/ml, the pleural biopsy made specific diagnosis in no case. Final diagnosis of above 6 cases consisted of 4 malignant effusions, 1 malignancy associated effusion and 1 tuberculous pleurisy. Conclusion : In the diagnosis of 73 cases of lymphocyte dominant pleural effusions of which acid fast bacilli smear and cytologic exam was negative, percutaneous pleural biopsy diagnosed only in 35 cases. In the diagnosis of tuberculous pleurisy, the positive predictive value of higher ADA than 40 IU/L in lymphocyte dominant pleural effusion with negative AFB smear and negative cytologic exam was 100%. And the diagnostic efficacy of pleural biopsy was 57%. In cases of effusions with high CEA than 10ng/ml 83% and 0% respectively. Finally, we concluded that percutaneous pleural needle biopsy in the diagnosis of AFB smear negative and cytologic exam negative lymphocyte dominant exudative pleural effusion was not obligatory. especially in effusions with high ADA and low CEA value.

• Journal of Chest Surgery
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• v.31 no.11
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• pp.1049-1055
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• 1998

Background: Coronary artery bypass surgery is an important treatment for ischemic heart disease. Recently operative mortality and morbidity has decreased, however further improvement is necessary. Materials and methods: This study was designed to evaluate the risk of operative mortality and morbidity by retrospective method. From 1992 to 1997, eighty six patients underwent coronary artery bypass surgery. There were 61 males and 25 females aged 36~74 years(mean, 58.6). Fourteen patients(16%) had previous PTCA or stent insertion, 41 patients(48%) had unstable angina, and 45 patients(52%) had three vessel disease. Patients with low LV ejection fraction(<35%) were 7 cases and urgent or emergent operation were 10 cases. There were 6 cases of combined surgery which were mitral valve replacement(2 cases), aortic valve replacement(2 cases), ASD repair(1 case), and VSD repair(1 case). Average number of distal anastomosis was 3.5 per patient and average aortic cross clamp time was 115±38.3min. Preoperative risk factors were defined as follows: female, old age(>70 years), low body surface area(<1.5M2), PTCA or stent insertion history, hypercholesterolemia, smoking, hypertension, DM, COPD, urgent or emergent operation, left main disease, low LV ejection fraction(<35%), and combined surgery. Results: Operative mortality was 7cases(8%). As a postoperative morbidity, perioperative myocardial infarction was 6 cases, cerebrovascular accident 6 cases, reoperation for bleeding 5 cases, acute renal failure 4 cases, gastrointestinal complication 3 cases, and mediastinitis 3 cases. In the evaluation of operative risk factors, low body surface area, DM and low LV ejection fraction were found to be predictive risk factors of postoperative morbidity(p<0.05), and low ejection fraction was especially a risk factor of hospital mortality(p<0.05). Conclusions: In this study, low body surface area, DM and low LV ejection fraction were risk factors of postoperative morbidity and low ejection fraction was a risk factor of hospital mortality.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.619-624
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• 2008

Background: Secondary spontaneous pneumothorax is caused by various underlying lung diseases, and this is despite that primary spontaneous pneumotherax is caused by rupture of subpleural blebs. The treatment algorithm for secondary pneumothorax is different from that for primary pneumothorax. We studied the recurrence rate, the characteristics of recurrence and the treatment outcomes of the patients with secondary spontaneous pneumothorax. Material and Method: Between March 2005 to March 2007, 85 patients were treated for their first episodes of secondary spontaneous pneumothorax. We analyzed the characteristics and factors for recurrence of secondary spontaneous pneumothorax by conducting a retrospective review of the medical records. Result: The most common underlying lung disease was pulmonary tuberculosis (49.4%), and the second was chronic obstructive lung disease (27.6%), The recurrence rate was 47.1% (40/85). The second and third recurrence rates were 10.9% and 3.5%, respectively. The mean follow up period was $21.1{\pm}6.7$ months (range: $0{\sim}36$ month). For the recurrence cases, 70.5% of them occurred within a year after the first episode. The success rates according to the treatment modalities were thoracostomy 47.6%, chemical pleurodesis 74.4%, blob resection 71% and Heimlich valve application 50%. Chemical pleurodesis through the chest tube was the most effective method of treatment. The factor that was most predictive of recurrence was 'an air-leak of 7 days or more' at the first episode. (p=0.002) Conclusion: The patients who have a prolonged air-leak at the first episode of pneumothorax tend to have a higher incidence of recurrence. Further studies with more patients are necessary to determine the standard treatment protocol for secondary spontaneous pneumothorax.

• Clinical and Experimental Pediatrics
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• v.52 no.9
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• pp.1021-1028
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• 2009

Purpose:Medical therapy is the initial treatment for children with Graves disease to avoid complications of other treatments. However, optimal treatment for childhood Graves disease is controversial because most patients require relatively long periods of medical therapy and relapse is common after medication discontinuation. Therefore, this study aimed to search clinical or biochemical characteristics that could be used as remission predictors in Graves disease. Methods:We retrospectively studied children diagnosed with Graves disease, treated with anti-thyroid agents, and observed for at least 3 years. Patients were categorized into remission and non-remission groups, and the groups were compared to determine the variables that were predictive of achieving remission. Results:Sixty-four patients were enrolled, of which 37 (57.8%) achieved remission and 27 (42.2%) could not achieve remission until the last visit. Normalization of thyroid-stimulating hormone-binding inhibitory immunoglobulin (TBII) after treatment was faster in the remission group than in the non-remission group (remission group, $15.5{\pm}12.07$ vs. non-remission group, $41.69{\pm}35.70$ months). Thyrotropin-releasing hormone (TRH) stimulation tests were performed in 28 patients. Only 2 (8.3%) of 26 patients who showed normal or hyper-response in TRH stimulation test relapsed. Binary logistic regression analysis identified rapid achievement of TBII normalization after treatment as a significant predictor of remission. Six percent of patients achieved remission within 3 years and 55.8% achieved it within 6 years. Conclusion:Rapid achievement of TBII normalization can be a predictor of remission in childhood Graves disease. The TRH stimulation test can be a predictor of maintenance of remission.

• Journal of Nutrition and Health
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• v.41 no.5
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• pp.414-427
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• 2008

The purpose of the study was to develop an eating habit checklist for screening elementary school children at high risk of energy overintake. Dietary habits, food intake, anthropometric data were collected from 142 children (80 boys and 62 girls) in the 4th to 6th grades of elementary schools. Energy intake, fat intake, and percentage of Estimated Energy Requirement (%EER) were used as indices to detect the risk of energy overintake of the children. Pearson correlation coefficients were calculated between dietary habit scores and energy overintake indices in order to select questions included in the checklist. TV watching during the meal, meal speed, meal amount, overintake frequency, eatingout frequency, snack frequency, frequency of eating Ramyun or fast foods showed significant correlations with energy overintake indices. Stepwise regression analysis was performed to give each item a different weight by prediction strength. To determine the cut-off point of the test score, sensitivity, specificity, and positive predictive values were calculated. The 7-item checklist with test results from 0 to 13 points was developed, and those with equal or higher than 5 points were diagnosed as a risk group of energy overintake. Among our subjects 13.4% was diagnosed as the risk group. Mean energy intake of the subjects in the risk group and the normal group were 2,650 kcal and 1,640 kcal, respectively. However, there were no significant differences of Index of Nutritional Quality (INQ) of the other nutrients except eating fiber between the risk group and the normal group. This checklist will provide a useful screening tool to identify children at high risk of energy overintake.

• Journal of Nutrition and Health
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• v.42 no.1
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• pp.38-47
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• 2009

The purpose of the study was to develop an eating habit checklist for screening elementary school children at risk of inadequate micronutrient intake. Eating habits, food intake, and anthropometric data were collected from 142 children (80 boys and 62 girls) in the $4^{th}$ to $6^{th}$ grades of elementary schools. Percentage of Recommended Intakes (RI) and Mean Adequacy Ratio (MAR) of six micronutrients; vitamin A, riboflavin, vitamin C, calcium, iron, zinc, and the number of nutrients the children consumed below EAR among the six nutrients were used as indices to detect the risk of inadequate micronutrient intake. Pearson correlation coefficients were calculated between eating habit scores and inadequate micronutrient intake indices in order to select questions included in the checklist. Meal frequency, enough time for breakfast, regularity of dinner, appetite, eating frequencies of Kimchi, milk, fruits and beans showed significant correlations with indices of inadequate micronutrient intake. Stepwise regression analysis was performed to give each item a different weight by prediction strength. To determine the cut-off point of the test score, sensitivity, specificity, and positive predictive values were calculated. The 8-item checklist with test results from 0 to 12 points was developed, and those with equal or higher than 6 points were diagnosed as high-risk group of inadequate micronutrient intake, and those with 4 or 5 points were diagnosed as moderate-risk group. Among our subjects 14.1% was diagnosed as high-risk group, and 30.3% as moderate-risk group. The proportions of the subjects who consumed below EAR of all micronutrients but vitamin C were highest in the high-risk group, and there were significant differences in the proportions of the subjects with intake below EAR of all micronutrients except vitamin B6 among the three groups. This checklist will provide a useful screening tool to identify children at risk of inadequate micronutrient intake.

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

• Management & Information Systems Review
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• v.29 no.2
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• pp.1-25
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• 2010

This study attempted to empirically test the determinants of stock returns in Korean stock market applying multi-factor model proposed by Haugen and Baker(1996). Regression models were developed using 16 variables related to liquidity, risk, historical price, price level, and profitability as independent variables and 690 stock monthly returns as dependent variable. For the statistical analysis, the data were collected from the Kis Value database and the tests of forecasting power in this study minimized various possible bias discussed in the literature as possible. The statistical results indicated that: 1) Liquidity, one-month excess return, three-month excess return, PER, ROE, and volatility of total return affect stock returns simultaneously. 2) Liquidity, one-month excess return, three-month excess return, six-month excess return, PSR, PBR, ROE, and EPS have an antecedent influence on stock returns. Meanwhile, realized returns of decile portfolios increase in proportion to predicted returns. This results supported previous study by Haugen and Baker(1996) and indicated that firm-characteristic model can better predict stock returns than CAPM. 3) The firm-characteristic model has better predictive power than Fama-French three-factor model, which indicates that a portfolio constructed based on this model can achieve excess return. This study found that expected return factor models are accurate, which is consistent with other countries' results. There exists a surprising degree of commonality in the factors that are most important in determining the expected returns among different stocks.