• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.841-854
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• 2020

The paper explains the method to process, analyze and predict traffic patterns in Los Angeles county using Big Data and Machine Learning. The dataset is used from a popular navigating platform in the USA, which tracks information on the road using connected users' devices and also collects reports shared by the users through the app. The dataset mainly consists of information about traffic jams and traffic incidents reported by users, such as road closure, hazards, accidents. The major contribution of this paper is to give a clear view of how the large-scale road traffic data can be stored and processed using the Big Data system - Hadoop and its ecosystem (Hive). In addition, analysis is explained with the help of visuals using Business Intelligence and prediction with classification machine learning model on the sampled traffic data is presented using Azure ML. The process of modeling, as well as results, are interpreted using metrics: accuracy, precision and recall.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.25 no.1
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• pp.27-30
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• 2014

Objectives : The purpose of this study was to investigate the endoscopic evidence of esophagitis in laryngopharyngeal reflux disease (LPRD) patients using transnasal esophagoscopy (TNE) and to correlate these findings with treatment response. Methods : Fifty patients underwent TNE at Korea University Anam Hospital from July 2007 to Feb 2009. Participants were selected from patients that presented with various laryngeal symptoms. One experienced otolaryngologist assessed esophagitis according to the Los Angeles classification system using the TNE findings. Results : Fifteen of 50 LPR patients (30%) were found to have esophagitis (12 patients with Grade A, 3 patients with Grade B, no patients with grade C/ D esophagitis). Among the 15 patients positive for esophagitis based on the endoscopic findings, 12 (80%) showed symptom improvement after pharmacological therapy. Symptom improvement was correlated with evidence of esophagitis (p=0.002) but not with RFS (p=0.749). Conclusion : Endoscopic evaluation of esophagitis using TNE is a potentially valuable tool for predicting treatment response in LPRD patients.

• Proceedings of the KOR-BRONCHOESO Conference
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• 2010.03a
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• pp.44-44
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• 2010

• Asia pacific journal of information systems
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• v.29 no.1
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• pp.35-49
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• 2019

The paper attempts to document the application of relevant Machine Learning (ML) models on Yelp (a crowd-sourced local business review and social networking site) dataset to analyze, predict and recommend business. Strategically using two cloud platforms to minimize the effort and time required for this project. Seven machine learning algorithms in Azure ML of which four algorithms are implemented in Databricks Spark ML. The analyzed Yelp business dataset contained 70 business attributes for more than 350,000 registered business. Additionally, review tips and likes from 500,000 users have been processed for the project. A Recommendation Model is built to provide Yelp users with recommendations for business categories based on their previous business ratings, as well as the business ratings of other users. Classification Model is implemented to predict the popularity of the business as defining the popular business to have stars greater than 3 and unpopular business to have stars less than 3. Text Analysis model is developed by comparing two algorithms, uni-gram feature extraction and n-feature extraction in Azure ML studio and logistic regression model in Spark. Comparative conclusions have been made related to efficiency of Spark ML and Azure ML for these models.

• Clinics in Shoulder and Elbow
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• v.21 no.2
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• pp.59-66
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• 2018

Background: Massive, irreparable rotator cuff tears (RCTs) are a challenging clinical problem in young patients. In recent years, arthroscopic superior capsular reconstruction (ASCR) is a popular treatment in the massive, irreparable RCTs. However, studies reporting clinical results of ASCR are rare in the literature. Methods: Between 2013 and 2015, six patients underwent ASCR. One patient treated with dermal allograft, while five patients with autogenous fascia lata graft. Demographic data, as well as preoperative and last follow-up clinical data including pain, range of motion (ROM), strength, American Shoulder and Elbow Surgeons system, the Constant system, the University of California at Los Angeles system, the Simple Shoulder Test, and the Shoulder Pain and Disability Index system were obtained. Acromiohumeral distances and Hamada classification were measured on standard anteroposterior x-ray. Results: All patients were men, and the average age was $59.5{\pm}4.18years$ (range, 53-65 years).The minimum follow-up was 18 months with a mean follow-up was $27.33{\pm}7.58months$ (range, 18-36). All patients had postoperative improvement in pain scores and functional scores. The ROM and strength did not improve after surgery. The Hamada score progressed of radiographic stage in 2 patients. In the case of dermal allograft, there was graft failure 6 weeks after ASCR. Conclusions: Our results support the ASCR as a viable treatment for surgical salvage in massive, irreparable RCTs. This treatment option may provide patients with decreased pain and increased function. And studying our case of dermal allograft failure provides opportunities to decrease graft failure in ASCR using dermal allograft.

• Clinics in Shoulder and Elbow
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• v.19 no.2
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• pp.73-77
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• 2016

Background: The first purpose of this study is to compare the clinical and radiological outcomes of surgical treatment for displaced midshaft clavicle fracture (Robinson type 2B1 vs. 2B2) with 3.5-mm low profile clavicular locking compression plate. The second purpose is to evaluate the difference of the results depending on the presence of accompanying injuries. Methods: Forty-nine patients who underwent an operation for the fractures were reviewed retrospectively. Fracture patterns were classified according to group 2B1 and 2B2 using Robinson's classification. For radiological outcome, time to union after operation was evaluated and for clinical outcome, American Shoulder and Elbow Society (ASES) score, University of California in Los Angeles (UCLA) score, visual analogue scale (VAS), and range of motion (ROM) were evaluated from preoperative period to last follow-up period. Results: The mean time for union was not significantly different in the 2B1 group and 2B2 group (p=0.062). No statistically significant difference in ASES score, UCLA score, and VAS was observed between 2B1 and 2B2 (p=0.619, p=0.896, p=0.856, respectively). In ROM, significant higher mean forward flexion and abduction was observed in 2B2 (p=0.025, p=0.017, respectively) and there was no difference in external rotation and external rotation at shoulder $90^{\circ}$ abduction position (p=0.130, p=0.180, respectively). There was no significant difference in clinical outcomes according to the accompanying injuries. Conclusions: There was no difference in clinical and radiological outcome between Robinson 2B1 and 2B2 type fracture after the operation. Accompanying injuries may not affect the clinical result of displaced midshaft clavicle fractures.

• Clinics in Shoulder and Elbow
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• v.22 no.4
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• pp.203-209
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• 2019

Background: Clinical outcomes and prognosis of large and massive rotator cuff tears are known to be unpredictable not only in degeneration of the rotator cuff, but also due to a high rate of retear. Methods: Totally, 81 patients who had undergone arthroscopic rotator cuff repair from May 2008 to February 2016 were evaluated in our study. Clinical and functional evaluations were performed with the Constant score and the University of California, Los Angeles (UCLA) score, as well as full physical examination of the shoulder. All patients were confirmed to have magnetic resonance imaging (MRI) of tendon healing at least 1 year postoperatively. Results: The average age at the time of surgery was 65 years (range, 47-78 years). The average duration of postoperative time in which a follow-up MRI was performed was 36.1 months (range, 12-110 months). Large tears were present in 48 cases (59.3%) and massive tears in 33 cases (40.7%). Overall, there were 33 retear cases (40.7%). All the average clinical outcome scores were significantly improved at the last follow-up (p<0.001), although repair integrity was not maintained. Compared to type A, types C, and D of the Collin's classification showed significantly higher retear rates (p=0.036). Conclusions: Arthroscopic rotator cuff repair yields improved clinical outcomes and a relatively high degree of patient satisfaction, despite the repair integrity not being maintained. Involvement of the subscapularis muscle or infraspinatus muscle had no effect on the retear rate.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.180-188
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• 2009

Purpose: We evaluate the short-term clinical outcome of arthroscopic rotator cuff tendon repair with suture-bridge technique in patients with full thickness rotator cuff tear. Materials and Methods: 29 (male:17, female:12) consecutive shoulders treated with this index procedure and early rehabilitation were enrolled. Mean age was 56.4 years (range, 34~73 years) and mean follow-up period was 13 months (range, 12-15 months). Clinical outcomes were evaluated by using the University of California Los Angeles (UCLA) score, the Korean Shoulder Scoring System (KSS) and Visual Analogue Scale (VAS). Postoperative cuff integrity was evaluated through magnetic resonance imaging (MRI) and categorized by Sugaya classification. Results: Postoperative UCLA scores improved from 16.4 to 31.6 (p< 0.05) and KSS scores showed 88 at 6 months and 92 at last follow up. Preoperative VAS score was 8.6, which was decreased to 2.1 at 3 months and 1.4 at 6 months postoperatively. 28 patients (96.5%) had increase in range of motion. The follow up MRI was taken in 15 shoulders and the cuff integrity was type I in 6 cases, type II in 7, type III in 1 and type V in 1 by Sugaya classification. Conclusion: Arthroscopic suture-bridge technique resulted in good or excellent clinical outcome in 96.5% of the cases, so we think this technique is one of the reliable procedure for full-thicknes rotator cuff tear.

• Journal of Gastric Cancer
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• v.15 no.1
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• pp.46-52
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• 2015

Purpose: The aim of this study was to compare the short-term surgical and long-term functional outcomes of Billroth I, Billroth II, and Roux-en-Y reconstruction after laparoscopic distal gastrectomy. Materials and Methods: We retrospectively collected data from 697 patients who underwent laparoscopic distal gastrectomy for operable gastric cancer between January 2009 and December 2012. The patients were classified into three groups according to the reconstruction methods: Billroth I, Billroth II, and Roux-en-Y. The parameters evaluated included patient and tumor characteristics, operative details, and postoperative complications classified according to the Clavien-Dindo classification. Endoscopic findings of the remnant stomach were evaluated according to the residue, gastritis, bile (RGB) classification and the Los Angeles classification 1 year postoperatively. Results: Billroth I, Billroth II, and Roux-en-Y were performed in 165 (23.7%), 371 (53.2%), and 161 patients (23.1%), respectively. Operation time was significantly shorter ($173.4{\pm}44.7$ minute, P<0.001) as was time to first flatus ($2.8{\pm}0.8$ days, P=0.009), time to first soft diet was significantly faster ($4.3{\pm}1.0$ days, P<0.001), and postoperative hospital stay was significantly shorter ($7.7{\pm}4.0$ days, P=0.004) in Billroth I in comparison to the other methods. Postoperative complications higher than Clavien-Dindo grade III occurred in 61 patients (8.8%) with no statistically significant differences between groups (P=0.797). Endoscopic findings confirmed that gastric residue, gastritis, bile reflux, and reflux esophagitis were significantly lower in Roux-en-Y (P<0.001) patients. Conclusions: Roux-en-Y reconstruction after laparoscopic distal gastrectomy for middle-third gastric cancer is beneficial in terms of long-term functional outcome, whereas Billroth I reconstruction for distal-third gastric cancer has a superior short-term surgical outcome and postoperative weight change.

• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.38-45
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• 2020

Purpose: To examine the clinical and structural outcomes of an at least two-year follow-up of arthroscopic full-thickness rotator cuff repairs with a single-row or suture-bridge technique in patients more than 65 years of age. Materials and Methods: Patients diagnosed with a full-thickness rotator cuff tear who were more than 65 years of age, underwent arthroscopic rotator cuff repair after at least six months of conservative treatment, agreed to take a follow-up magnetic resonance imaging (MRI) six months postoperatively, and visited outpatient for at least two years were enrolled in this study. Clinical evaluations were done using The University of California Los Angeles score, Constant Shoulder Score, and visual analogue scale evaluated two years after the surgery. The structural integrity was analyzed using follow-up MRI. During surgery, a suture-bridge technique was used if the rotator cuff tendon could cover half of the footprint under constant tension. Otherwise, single-row repair was performed. Results: The samples were 158 cases, consisting of 93 single-repairs and 65 suture-bridge repairs. A preoperative comparison of the age distribution, fatty degeneration of supraspinatus and infraspinatus muscle, medial retraction of torn cuff tendon, and tear size between the two groups were not significant. The clinical scores were improved significantly in all cases. The distribution of the structural integrity by Sugaya classification were 49 cases in type 1 (31.0%), 62 cases in type 2 (39.2%), 30 cases in type 3 (19.0%), 11 cases in type 4 (7.0%), and six cases in type 5 (3.8%). The re-tear rate of the single-row group was 9.7% (nine out of 93 cases) and 12.3% (eight out of 65 cases) for the suture-bridge group. Conclusion: Satisfactory clinical and radiological outcomes were achieved after arthroscopic full-thickness rotator cuff repair in patients more than 65 years of age. Both single-row and suture-bridge techniques would be beneficial for the elderly.