• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.111-126
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• 2017

Recommender systems based on association rule mining significantly contribute to seller's sales by reducing consumers' time to search for products that they want. Recommendations based on the frequency of transactions such as orders can effectively screen out the products that are statistically marketable among multiple products. A product with a high possibility of sales, however, can be omitted from the recommendation if it records insufficient number of transactions at the beginning of the sale. Products missing from the associated recommendations may lose the chance of exposure to consumers, which leads to a decline in the number of transactions. In turn, diminished transactions may create a vicious circle of lost opportunity to be recommended. Thus, initial sales are likely to remain stagnant for a certain period of time. Products that are susceptible to fashion or seasonality, such as clothing, may be greatly affected. This study was aimed at expanding association rules to include into the list of recommendations those products whose initial trading frequency of transactions is low despite the possibility of high sales. The particular purpose is to predict the strength of the direct connection of two unconnected items through the properties of the paths located between them. An association between two items revealed in transactions can be interpreted as the interaction between them, which can be expressed as a link in a social network whose nodes are items. The first step calculates the centralities of the nodes in the middle of the paths that indirectly connect the two nodes without direct connection. The next step identifies the number of the paths and the shortest among them. These extracts are used as independent variables in the regression analysis to predict future connection strength between the nodes. The strength of the connection between the two nodes of the model, which is defined by the number of nodes between the two nodes, is measured after a certain period of time. The regression analysis results confirm that the number of paths between the two products, the distance of the shortest path, and the number of neighboring items connected to the products are significantly related to their potential strength. This study used actual order transaction data collected for three months from February to April in 2016 from an online commerce company. To reduce the complexity of analytics as the scale of the network grows, the analysis was performed only on miscellaneous goods. Two consecutively purchased items were chosen from each customer's transactions to obtain a pair of antecedent and consequent, which secures a link needed for constituting a social network. The direction of the link was determined in the order in which the goods were purchased. Except for the last ten days of the data collection period, the social network of associated items was built for the extraction of independent variables. The model predicts the number of links to be connected in the next ten days from the explanatory variables. Of the 5,711 previously unconnected links, 611 were newly connected for the last ten days. Through experiments, the proposed model demonstrated excellent predictions. Of the 571 links that the proposed model predicts, 269 were confirmed to have been connected. This is 4.4 times more than the average of 61, which can be found without any prediction model. This study is expected to be useful regarding industries whose new products launch quickly with short life cycles, since their exposure time is critical. Also, it can be used to detect diseases that are rarely found in the early stages of medical treatment because of the low incidence of outbreaks. Since the complexity of the social networking analysis is sensitive to the number of nodes and links that make up the network, this study was conducted in a particular category of miscellaneous goods. Future research should consider that this condition may limit the opportunity to detect unexpected associations between products belonging to different categories of classification.

• Journal of Oral Medicine and Pain
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• v.36 no.1
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• pp.39-51
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• 2011

The aims of this study were to investigate whether the facial skeletal patterns previously reported to be related to temporomandibular disorder (TMD) in other studies could be consistently observed in the TMD patients diagnosed according to Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) Axis I and evaluate its usability in the orthodontic clinics to examine the patients with TMD related symptoms. The clinical records and radiographs of female patients who visited the TMD and Orofacial Pain Clinic of Seoul National University Dental Hospital and were diagnosed as TMD were consecutively filed for this study. Patients were clinically examined and diagnosed according to the revised diagnostic algorithms of RDC/TMD Axis I and the lateral cephalogram, panoramic orthopantomogram, temporomandibular joint (TMJ) orthopantomogram, and transcranial radiograph of each patient were taken and digitalized. The data of patients who were under 18 years of age or had any systemic disease, trauma history involving the TMJ, or skeletal deformity at the time of the first examination were excluded. The remaining data of 96 female patients were finally analyzed. The obtained results were as follows: 1. There are no significant differences of cephalometric measurements between RDC I (muscle disorders) diagnostic groups. 2. Only the articular angle of the RDC group IIc (disk displacement without reduction without limited opening) patients was larger than patients of the no diagnosis of RDC II group (disk displacement). 3. Larger articular angle and smaller facial height ratio were observed in RDC IIIc group (osteoarthrosis) compared to IIIa group (arthralgia). Larger articular angle, larger Bjork sum, smaller posterior facial height, and smaller facial height ratio were observed in RDC group IIIc compared to no diagnosis of RDC III group (arthralgia, arthritis, and arthrosis). 4. According to the results of cephalometric analysis in simplified RDC groups, smaller overjet was observed in muscle disorders (MD) group. Facial height ratio and IMPA were smaller and articular angle was larger in disk displacements (DD) group than in no diagnosis of DD group. In arthrosis (AR) group, posterior facial height, and facial height ratio were smaller, and articular angle, gonial angle, facial convexity, FMA, Bjork sum, and ANB were larger than in no diagnosis of AR group. In joint pain (JP) group, only posterior facial height was smaller than no diagnosis of JP group. In conclusion, Facial morphologic patterns showing posterior-rotated mandible and lower posterior facial height is related to RDC group II and III diagnosis of the TMJ in female TMD patients. RDC/TMD Axis I diagnosis can provide a good clinical diagnostic tool for the standardized examination of the TMJ in orthodontic clinics.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1519-1527
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• 2002

Purpose : Although influenza virus is one of the most important causes of acute respiratory tract infections(ARTIs) in children, virus isolation is not popular and there are only a few clinical studies on influenza in Korea. We evaluated the epidemiologic and clinical features of ARTIs by influenza virus in children. Methods : From February 1995 to August 2001, nasopharyngeal aspirations were obtained and cultured for the isolation of influenza virus in children admitted with ARTIs. The medical records of patients with influenza virus infection were reviewed retrospectively. Results : Respiratory viruses were isolated in 997(22.0%) out of 4,533 patients examined, and influenza virus was isolated in 164 cases(3.6%). Influenza virus was isolated year after year mainly from December to April of next year. The ratio of male and female was 1.9 : 1 with a median age of 15 months. The most common clinical diagnosis of influenza virus infection was pneumonia, and fever and cough developed in most patients. There was no difference between influenza A and B infection in clinical diagnoses and symptoms. All patients recovered without receiving antiviral treatment except for one patient diagnosed with pneumonia who had underlying disease of Down syndrome with ventricular septal defect. Conclusion : ARTIs caused by influenza virus developed every winter and spring during the period of study. Because fatal complication can develop in the high risk group, prevention, early diagnosis and proper management of influenza should be emphasized.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.2
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• pp.156-162
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• 2009

Purpose: The aim of this study was to investigate the clinical usefulness of upper gastrointestinal (GI) endoscopy in children with Henoch-Sch$\"{o}$nlein purpura (HSP). Methods: We retrospectively analyzed the clinical, endoscopic, and histopathologic records of children with HSP who had been admitted to the Department of Pediatrics of Gil Hospital and underwent upper GI endoscopy between January 2002 and June 2009. Patients were classified into the following two groups for statistical analysis: duodenal involvement (+) and duodenal involvement (-). Results: Fifty-one children with HSP underwent upper GI endoscopy; the mean age was 7.2${\pm}$2.9 years. The upper GI endoscopy showed abnormalities of the duodenum in 38 cases (74.5%), 22 of which had duodenal ulcers. Among the biopsy specimens obtained from the duodenum of 37 cases, 13 cases (35.1%) had leukocytoclastic vasculitis, neutrophil debri, and/or extravasation of RBCs. Steroid use was more frequent in the duodenal involvement (+) group (86.8%) than the duodenal involvement (-) group (53.8%; p=0.02). The mean length of hospitalization was 13.9${\pm}$8.43 days in the duodenal involvement (+) group and 8.1${\pm}$4.62 days in the duodenal involvement (-) group (p=0.003). The recurrence rate was significantly higher in the duodenal involvement (-) group than the duodenal involvement (+) group (p=0.027), whereas none of the other study parameters, such as the age of onset, renal involvement, and steroid use, led to significantly higher or lower recurrence rates. Conclusion: These results suggest that duodenal involvement can influence the clinical course and prognosis of HSP in children.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.168-177
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• 2007

Purpose : The purpose of this study was to investigate whether hypercalciuria patients with hematuria show different renal indices compared to non-hypercalciuria patients with hematuria. Methods : We retrospectively reviewed the medical records of patients with gross or microscopic hematuria whose blood chemistry and 24 hour urine chemistry were examined. After excluding the patients with more than $4 mg/m^2/day$ proteinuria or the patients with urinary calcium excretion between 3 and 4 mg/kg/day, we divided the patients into two groups: a hypercalciuria group whose calcium excretion was more than 4 mg/kg/day(n=30) and a non hypercalciuria group whose calcium excretion was less than 3 mg/kg/day(n=41). The urinary excretion, clearance, and fractional excretion(FE) of Na, K, Cl, Ca, P, urea, and creatinine were calculated and compared between the two groups. Results : The hypercalciuria group had more calcium excretion($6.1{\pm}2.9$ vs $1.5{\pm}0.9 mg/kg/day$), more urea excretion($341{\pm}102$ vs $233{\pm}123 mg/kg/day$), greater glomerular filtration rate(GFR) ($93.7{\pm}31.1$ vs $79.5{\pm}32.0 mL/min$) but lower FENa($1.0{\pm}0.4%$ vs $1.3{\pm}0.6%$) than the nonhyper-calciuria group, although the urinary sodium excretion was similar between the two groups. Conclusion : The greater urea excretion and GFR in hypercalciuric patients suggest that they might be on a higher protein diet than the non-hypercalciuria group. The increased glomerular filtration of sodium and calcium induced by the higher GFR in hypercalciuria would have increased their delivery to the distal tubule, where sodium is effectively reabsorbed but calcium is not, which is suggested by the lower FENa but higher FECa in hyercalciuria. It is recommended that the diet of hematuria patients be reviewed in detail at initial presentation and during treatment.

• Journal of Chest Surgery
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• v.39 no.1 s.258
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• pp.18-27
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• 2006

Background: Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly, but is one of the most common causes of myocardial ischemia which would result in high mortality within the first year of life. This is our early result of the surgical management for these patients. Material and Method: From June 1989 to July 2003, 6 patients with ALCAPA and one patient with ARCAPA (Anomalous origin of the Right coronary artery from the pulmonary artery) underwent surgical repair. We have reviewed the all medical records, electrocardiogram, chest X-ray and echocardiography retrospectively. Result: Three of the patients were boys and four were girls. The median age at the operation was 5.4 months (Range: 3$\∼$33 months). The average body weight of at the operation was 6.7 kg (Range: 3.7$\∼$11.3 kg). A mean follow up period was 18 months. Only 3 patients were initially diagnosed as ALCAPA. And 3 patients had moderate mitral regurgitation. Immediate coronary artery reimplantation on diagnosis with the aim of restoring a two-coronary system circulation was done. The average bypass time was 114$\pm$37 minutes, and the average aortic cross clamping time was 55$\pm$22 minutes. The average stay of intensive care unit was 5$\pm$3 days, the mean mechanical ventilator time was 38$\pm$45 hours and the hospital stay after operation was 12$\pm$5 days. There were significant improvements in electrocardiogram and chest X-ray of the all patients except one late death patient. The ventricular function showed almost normal recovery after operation; the EF (Ejection Fraction) increased from 41.2$\pm$ 10.3$\%$ to 60.5$\pm$ 15.8$\%$ within 1 month and to 59.8$\pm$13.9$\%$ within 1 year after operation, the SF (Shortening Fraction) increased from 23.6$\pm$4.7$\%$ to 38.6$\pm$8.4$\%$ within 1 month and to 37.4$\pm$7.9$\%$ within 1 year after operation, LVEDDI (Left Ventricular End-diastolic Dimension Index) decreased from 100.8$\pm$25.6 mm/$m^{2}$ to 90.3$\pm$ 19.2 mm/$m^{2}$ within f month and to 79.3$\pm$ 15.8 mm/$m^{2}$ within 1 year after operation. Concomitant mitral repair was done in two patients with anterior mitral leaflet prolapse. In every patient, mitral valve showed less than mild regurgitation during follow up. One late death occurred in which patient Dor procedure was applied 10 months after initial operation due to the dilated cardiomyopathy Conclusion: In the management of this rare and could be fatal Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA), early suspicion and correct diagnosis is of most important. But, after diagnosis, immediate restoration of 2 coronary systems could result in good outcome.

• Pediatric Infection and Vaccine
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• v.9 no.2
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• pp.163-174
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• 2002

Background : To delineate the changes in the causative agents of neonatal sepsis and their antimicrobial susceptibilities in the neonatal intensive care unit and nursery of Hanyang University Hospital during the past 10 years. Methods : Hospital records of 15,144 patients hospitalized at the NICU and nursery of Hanyang University Hospital from 1989 to 1998 were reviewed and neonates diagnosed of neonatal sepsis were sorted and included in the study. The study period was divided into Period A(the first 5 years) and Period B(the second 5 years) to analyse causative agents and their antimicrobial susceptibilities. Results : Neonatal sepsis was diagnosed in 170 patients(1.1%{Period A 1.2%, Period B 1.0%}) among the total of 15,144 inpatients. Two hundred isolates(Period A 109 isolates, Period B 91 isolates) were identified in 186 blood cultures(Period A 99 cultures, Period B 87 cultures) from 170 patients(Period A 91 patients, Period B 79 patients). The average age at the onset of the disease, when the initial blood culture was drawn, was 12.3 days old(Period A 8.8 days, Period B 16.3 days), and the proportion of the early onset disease was 34.7% in Period A and 23.0% in Period B, indicating that neonatal sepsis developed earlier during Period A. Among the isolated organisms including Gram positive bacteria[132(66.0%)], Gram negative bacteria [60(30.0%)], and fungi[8(4.0%)], coagulase negative Staphylococcus(CNS) was the most common organism(69/34.5%), followed by Staphylococcus aureus(36/18.0%), Klebsiella pneumoniae(17/8.5%), Enterococcus(12/6.0%), Enterobacter cloacae(8/4.0%), Escherichia coli(6/3.0%), and Pseudomonas aeruginosae(5/2.5%). The isolated fungi were Candida parapsilosis, Candida albicans, and Trichosporon pullulans. CNS, S. aureus and Acinetobacter baumannii were isolated more frequently in Period A compared to Period B. Antimicrobial susceptibilities of CNS and S. aureus to methicillin and the first generation cephalo sporins were decreased in Period B compare to Period A, those to aminoglycosides were increased in Period B, and vancomycin resistant strains were not identified. K. pneumoniae, Enterococcus, E. coli, and P. aeruginosa were isolated less frequently in Period B, compared to Period A. For K. pneumoniae, antimicrobial susceptibilities to the first generation cephalosporins were low in both Periods A and B, those to tobramycin and gentamicin were increased in Period B, and those to amikacin, ceftriaxone, and trimethoprim-sulfamethoxazole were high in both Periods A and B. Antimicrobial susceptibilities of Enterococcous to ampicillin, penicillin, and the first generation cephalosporins were decreased in Period B, but vancomycin resistant strains were not identified. Conclusion : The occurrence rate of neonatal sepsis during the past 10 years in the NICU and nursery of the Hanyang University hospital was 1.1%, and the most common causitive agents were CNS and S. aureus, to which the antimicrobial susceptibilities to the first line drugs decreased in the later half of the study period with no vancomycin resistant isolates identified. Group B Streptococcus known to be the most common agent causing neonatal sepsis was not identified, and K. pneumoniae was isolated more commonly during the later half of the study period without decreased antimicrobial susceptibilities.

• Pediatric Infection and Vaccine
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• v.11 no.2
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• pp.158-169
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• 2004

Purpose : Although influenza is one of the most important cause of acute respiratory tract infections in children, virus isolation is not popular and there are only a few clinical studies on influenza and diagnostic methods. We evaluated the epidemiological and clinical features of influenza in children and rapid antigen detection test(QuickVue influenza test) on fist half of the year 2004 in Busan. Methods : From January 2004 to June 2004, throat swab and nasal secretion were obtained and cultured for the isolation of influenza virus and tested by rapid antigen detection test(QuickVue influenza test) in children with suspected influenza infections. The medical records of patients with influenza virus infection were reviewed retrospectively. Results : Influenza viruses were isolated in 79(17.2%) out of 621 patients examined. Influenza virus was isolated mainly from March to April 2004. The ratio of male and female with influenza virus infection was 1.2 : 1 with median age of 4 years 6month. The most common clinical diagnosis of influenza virus infection was bronchitis. There was no difference between influenza A and B infection in clinical diagnosis and symptoms. All patients recovered without severe complication. The sensitivity obtained for rapid antigen detection test (QuickVue influenza test) was 93.6% and the specificity was 80.2%, the positive predictive value 40.8%, the negative predictive value 98.8%. Conclusion : With rapid antigen detection test, it is possible early detection of influenza in children. reduction in use of antimicrobial agent and early use of antiviral agent.

• 한국유가공학회:학술대회논문집
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• 2007.09a
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• pp.49-58
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• 2007

Inflammatory process leads to the well-known mucosal damage and therefore a further disturbance of the epithelial barrier function, resulting abnormal intestinal wall function, even further accelerating the inflammatory process[1]. Despite of the records, etiology and pathogenesis of IBD remain rather unclear. There are many studies over the past couple of years have led to great advanced in understanding the inflammatory bowel disease(IBD) and their underlying pathophysiologic mechanisms. From the current understanding, it is likely that chronic inflammation in IBD is due to aggressive cellular immune responses including increased serum concentrations of different cytokines. Therefore, targeted molecules can be specifically eliminated in their expression directly on the transcriptional level. Interesting therapeutic trials are expected against adhesion molecules and pro-inflammatory cytokines such as TNF-${\alpha}$. The future development of immune therapies in IBD therefore holds great promises for better treatment modalities of IBD but will also open important new insights into a further understanding of inflammation pathophysiology. Treatment of cytokine inhibitors such as Immunex(Enbrel) and J&J/Centocor(Remicade) which are mouse-derived monoclonal antibodies have been shown in several studies to modulate the symptoms of patients, however, theses TNF inhibitors also have an adverse effect immune-related problems and also are costly and must be administered by injection. Because of the eventual development of unwanted side effects, these two products are used in only a select patient population. The present study was performed to elucidate the ability of TNF-${\alpha}$ antibodies produced in sheep colostrums to neutralize TNF-${\alpha}$ action in a cell-based bioassay and in a small animal model of intestinal inflammation. In vitro study, inhibitory effect of anti-TNF-${\alpha}$ antibody from the sheep was determined by cell bioassay. The antibody from the sheep at 1 in 10,000 dilution was able to completely inhibit TNF-${\alpha}$ activity in the cell bioassay. The antibodies from the same sheep, but different milkings, exhibited some variability in inhibition of TNF-${\alpha}$ activity, but were all greater than the control sample. In vivo study, the degree of inflammation was severe to experiment, despite of the initial pilot trial, main trial 1 was unable to figure out of any effect of antibody to reduce the impact of PAF and LPS. Main rat trial 2 resulted no significant symptoms like characteristic acute diarrhea and weight loss of colitis. This study suggested that colostrums from sheep immunized against TNF-${\alpha}$ significantly inhibited TNF-${\alpha}$ bioactivity in the cell based assay. And the higher than anticipated variability in the two animal models precluded assessment of the ability of antibody to prevent TNF-${\alpha}$ induced intestinal damage in the intact animal. Further study will require to find out an alternative animal model, which is more acceptable to test anti-TNF-${\alpha}$ IgA therapy for reducing the impact of inflammation on gut dysfunction. And subsequent pre-clinical and clinical testing also need generation of more antibody as current supplies are low.

• Tuberculosis and Respiratory Diseases
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• v.51 no.5
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• pp.416-425
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• 2001

Background : The incidence of drug-resistant tuberculosis has recently decreased in Korea. However, it is still one of the major obstacles in treating pulmonary tuberculosis. This study was performed to determine the prevalence and clinical characteristics associated with drug-resistance in pulmonary tuberculosis at the tertiary referral hospital in Pusan, Korea. Methods : The medical records of 138 patients, who had been diagnosed as active pulmonary tuberculosis were retrospectively reviewed, and results of drug susceptibility from May 1997 to June 2000. The relationships among those with a history of previous tuberculosis treatment, the extent of lung involvement, the presence of cavities on the initial chest X-ray films and patterns of drug resistance were analyzed. Results : The total number of patients who had drug resistance to at least one drug was 55(39.9%). Among them 34(24.6%) had resistance to isoniazid(INH) and rifampin(RFP). There was drug resistance in 20(22%) of 91 patients without previous tuberculosis therapy, and among them 9(9.9%) were multi-drug resistant. Thirty-two(74.5%) out of 47 patients with previous therapy were drug-resistant and 25(53.2%) were multidrug resistant. For all 138 patients, resistance to INH was the most common(34.1%), followed by RFP(26.1%) and ethambutol(EMB)(14.5%). Drug resistance to INH, RFP, PZA and streptomycin(SM) were independently associated with a history of previous treatment(odds ratio; 9.43, 9.09, 8.93 and 21.6 respectively, p<0.01). The extent of lung involvement on the chest films was significantly associated with the drug resistance to INH and RFP(odds ratio; 2.12 and 2.40 respectively, p<0.01). The prevalence of drug resistance to RFP, INH and RFP was significantly more common in patients with a cavitary lesion on the chest films by multivariate analysis(odds ratio; 4.17 and 4.81 respectively, p<0.05). Conclusion : This study revealed that patients with a prior treatment history for pulmonary tuberculosis, and the presence of a cavitary lesion on chest films had a higher prevalence of anti-tuberculosis drug resistance. A very careful clinical and microbiological examination is needed for patients with such characteristics.