• Smart Structures and Systems
• /
• v.29 no.1
• /
• pp.117-127
• /
• 2022

Data anomalies seriously threaten the reliability of the bridge structural health monitoring system and may trigger system misjudgment. To overcome the above problem, an efficient and accurate data anomaly detection method is desiderated. Traditional anomaly detection methods extract various abnormal features as the key indicators to identify data anomalies. Then set thresholds artificially for various features to identify specific anomalies, which is the artificial experience method. However, limited by the poor generalization ability among sensors, this method often leads to high labor costs. Another approach to anomaly detection is a data-driven approach based on machine learning methods. Among these, the bidirectional long-short memory neural network (BiLSTM), as an effective classification method, excels at finding complex relationships in multivariate time series data. However, training unprocessed original signals often leads to low computation efficiency and poor convergence, for lacking appropriate feature selection. Therefore, this article combines the advantages of the two methods by proposing a deep learning method with manual experience statistical features fed into it. Experimental comparative studies illustrate that the BiLSTM model with appropriate feature input has an accuracy rate of over 87-94%. Meanwhile, this paper provides basic principles of data cleaning and discusses the typical features of various anomalies. Furthermore, the optimization strategies of the feature space selection based on artificial experience are also highlighted.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.2
• /
• pp.95-109
• /
• 2023

In the 4th industrial revolution, changes in the technological paradigm have had a direct impact on the maintenance system of ships. The 2-stroke low speed engine system integrates with the core equipment required for propulsive power. The Condition Based Management (CBM) is defined as a technology that predictive maintenance methods in existing calender-based or running time based maintenance systems by monitoring the condition of machinery and diagnosis/prognosis failures. In this study, we have established a framework for CBM technology development on our own, and are engaged in engineering-based failure analysis, data development and management, data feature analysis and pre-processing, and verified the reliability of failure mode DB using LSTM algorithms. We developed various simulated failure mode scenarios for 2-stroke low speed engine and researched to produce data on onshore basis test_beds. The analysis and pre-processing of normal and abnormal status data acquired through failure mode simulation experiment used various Exploratory Data Analysis (EDA) techniques to feature extract not only data on the performance and efficiency of 2-stroke low speed engine but also key feature data using multivariate statistical analysis. In addition, by developing an LSTM classification algorithm, we tried to verify the reliability of various failure mode data with time-series characteristics.

• Journal of Yeungnam Medical Science
• /
• v.40 no.1
• /
• pp.65-77
• /
• 2023

Background: This study aimed to compare clinical outcomes between surveillance and adjuvant therapy (AT) groups after R0 resection for cholangiocarcinoma (CCA). Methods: A total of 154 patients who underwent R0 resection for CCA at the Daegu Catholic University Medical Center between January 2010 and December 2019 were included. Overall survival (OS) and progression-free survival (PFS) were analyzed. Results: The median follow-up duration was 899 days. There were 109 patients in the AT group and 45 patients in the surveillance group. The patients in the AT group were younger (67 years vs. 74 years, p<0.001) and included more males (64.2% vs. 46.7%, p=0.044). The proportion of patients with stage III CCA was larger in the AT group than in the surveillance group (13.8% vs. 2.2%, p=0.005). In addition, AT did not improve OS (5-year OS rate, 69.3% in the AT group vs. 64.2% in the surveillance group, p=0.806) or PFS (5-year PFS rate, 42.6% in the AT group vs. 48.9% in the surveillance group, p=0.113). In multivariate analysis using the Cox proportional hazards model, stage III CCA (hazard ratio [HR], 10.81; 95% confidence interval [CI], 2.92-40.00; p<0.001) was a significant predictor of OS. American Society of Anesthesiologists classification II (HR, 0.50; 95% CI, 0.31-0.81; p=0.005), and American Joint Committee on Cancer stages II (HR, 3.14; 95% CI, 1.25-7.89; p=0.015) and III (HR, 8.08; 95% CI, 2.80-23.32; p<0.001) were independent predictors of PFS. Conclusion: AT after R0 resection for CCA did not improve OS or PFS.

• Annals of Occupational and Environmental Medicine
• /
• v.35
• /
• pp.1.1-1.11
• /
• 2023

Background: Although it is well known that the usage of visual display terminal (VDT) at the workplace causes computer vision syndrome (CVS), previous studies mainly focused on computer use and the health of white-collar workers. In this study, we explored the relationship between the usage of VDT including various devices, and symptoms related to CVS in a large population including pink-collar workers and blue-collar workers. Methods: 21,304 wage workers over the age of 20 years were analyzed from the 6th Korean Working Conditions Survey. To investigate the association between VDT use at work and symptoms related to CVS among wage workers, odds ratios (ORs) and 95% confidence interval (CI) were calculated by multivariate logistic regression models. Results: In the group with the highest VDT usage at work, the OR of headache/eyestrain was 2.16 (95% CI: 1.86-2.52). The OR of suspected CVS patients was significantly increased in the highest group of usage of VDT at work (OR: 1.69; 95% CI, 1.39-2.06). Compare with the reference group, the OR for headache/eyestrain in the highest group of VDT usage was 2.81 (95% CI: 2.13-3.70) in white-collar workers, 1.78 (95% CI: 1.32-2.40) in pink-collar workers, and 1.59 (95% CI: 1.18-2.15) in blue-collar workers. Conclusions: We observed a relationship in which the use of VDT in the workplace increases the risk of headache/eyestrain regardless of occupational classification. Our findings emphasize the importance of paying attention to the health of VDT workers and making plans to improve their working conditions.

• Clinics in Shoulder and Elbow
• /
• v.26 no.4
• /
• pp.373-379
• /
• 2023

Background: The purpose of this study was to determine the association between smoking and clinical outcomes of hook plate fixation for acute acromioclavicular (AC) joint injuries. Methods: This study retrospectively investigated 82 patients who underwent hook plate fixation for acute AC joint dislocation between March 2014 to June 2022. The patients were grouped by smoking status, with 49 in group N (nonsmokers) and 33 in group S (smokers). Functional scores and active range of motion were compared among the groups at the 1-year follow-up. Coracoclavicular distance (CCD) was measured, and difference with the uninjured side was compared at initial injury and 6 months after implant removal. Results: No significant differences were observed between the two groups in demographic factors such as age and sex, as well as parameters related to initial injury status, which included time from injury to surgery, the preoperative CCD difference value, and the Rockwood classification. However, the postoperative CCD difference was significantly higher in group S (3.1±2.6 mm) compared to group N (1.7±2.4 mm). Multivariate regression analysis indicated that smoking and the preoperative CCD difference independently contributed to an increase in the postoperative CCD difference. Despite the radiographic differences, the postoperative clinical outcome scores and active range of motion measurements were comparable between the groups. Conclusions: Smoking had a detrimental impact on ligament healing after hook plate fixation for acute AC joint dislocations. This finding emphasizes the importance of smoking cessation to optimize reduction maintenance after AC joint injury. Level of evidence: III.

• Annals of Hepato-Biliary-Pancreatic Surgery
• /
• v.26 no.4
• /
• pp.325-332
• /
• 2022

Backgrounds/Aims: To analyze relationships of hepatic histopathological findings and bile microbiological profiles with perioperative outcomes and risk of late biliary stricture in individuals undergoing surgical bile duct injury (BDI) repair. Methods: A historical cohort study was carried out at a tertiary university hospital. Fifty-six individuals who underwent surgical BDI repair from 2014-2018 with a minimal follow-up of 24 months were enrolled. Liver biopsies were performed to analyze histopathology. Bile samples were collected during repair procedures. Hepatic histopathological findings and bile microbiological profiles were then correlated with perioperative and late outcomes through uni- and multi-variate analyses. Results: Forty-three individuals (76.8%) were females and average age was 47.2 ± 13.2 years; mean follow-up was 38.1 ± 18.6 months. The commonest histopathological finding was hepatic fibrosis (87.5%). Bile cultures were positive in 53.5%. The main surgical technique was Roux-en-Y hepaticojejunostomy (96.4%). Overall morbidity was 35.7%. In univariate analysis, liver fibrosis correlated with the duration of the operation (R = 0.3; p = 0.02). In multivariate analysis, fibrosis (R = 0.36; p = 0.02) and cholestasis (R = 0.34; p = 0.02) independently correlated with operative time. Strasberg classification independently correlated with estimated bleeding (R = 0.31; p = 0.049). The time elapsed between primary cholecystectomy and BDI repair correlated with hepatic fibrosis (R = 0.4; p = 0.01). Conclusions: Bacterial contamination of bile was observed in most cases. The degree of fibrosis and cholestasis correlated with operative time. The waiting time for definitive repair correlated with the severity of liver fibrosis.

• Journal of Gastric Cancer
• /
• v.20 no.2
• /
• pp.190-201
• /
• 2020

Purpose: This study sought to investigate the prognostic significance of tumor-infiltrating lymphocytes (TILs) in relation to tumor location within the stomach. Materials and Methods: The densities and prognostic significance of TIL subsets were evaluated in 542 gastric cancer patients who underwent gastrectomy. Immunohistochemical staining for CD3, CD4, CD8, forkhead/winged helix transcription factor (Foxp3), and granzyme B was performed. Results: Cardia cancer was associated with significantly lower densities of CD8 T-cells and higher densities of Foxp3 and granzyme B T-cells than non-cardia tumors. Multivariate analysis showed that advanced age (hazard ratio [HR], 1.023; 95% confidence interval [CI], 1.006-1.040), advanced T classification (HR, 2.029; 95% CI, 1.106-3.721), lymph node metastasis (HR, 3.319; 95% CI, 1.947-5.658), low CD3 expression (HR, 0.997; 95% CI, 0.994-0.999), and a high Foxp3/CD4 ratio (HR, 1.007; 95% CI, 1.001-1.012) were independent predictors of poor overall survival in cardia cancer patients. In non-cardia cancer patients, total gastrectomy (HR, 2.147; 95% CI, 1.507-3.059), advanced T classification (HR, 2.158; 95% CI, 1.425-3.266), lymph node metastasis (HR, 1.854; 95% CI, 1.250-2.750), and a low Foxp3/CD4 ratio (HR, 0.978; 95% CI, 0.959-0.997) were poor prognostic factors for survival. Conclusions: The densities and prognostic effects of TILs differed in relation to the location of tumors within the stomach. The contrasting prognostic effects of Foxp3/CD4 ratio in cardia and non-cardia gastric cancer patients suggests that clinicians ought to consider tumor location when determining treatment strategies.

• Clinical and Experimental Pediatrics
• /
• v.58 no.10
• /
• pp.386-391
• /
• 2015

Purpose: To evaluate the outcomes and prognostic factors in children with extracranial germ cell tumors (GCTs) treated at a single institution. Methods: Sixty-six children diagnosed with extracranial GCTs between 1996 and 2012 were included in the study. Primary treatment was surgical excision, followed by six cycles of cisplatin-based chemotherapy. The survival rates were compared according to the International Germ Cell Cancer Cooperative Group classification used for GCTs in adults to validate the classification guidelines for GCTs in children. Results: The median patient age was 4.4 years. In 34 patients (51.5%), the primary tumor site was the gonad. Extragonadal GCTs were detected in 32 patients. The 5-year overall survival and event-free survival (EFS) were $92.0%{\pm}3.5%$ and $90.4%{\pm}3.7%$, respectively. In univariate analysis, tumor histology, metastasis, and elevated alpha-fetoprotein were not prognostic factors in children with extracranial GCTs. However, EFS was poorer in patients with mediastinal disease (n=12, $66.7%{\pm}13.6%$) than in those with nonmediastinal disease (n=54, $96.0%{\pm}2.8%$) (P=0.001). The 5-year EFS was lower in patients older than 10 years, (n=21, $80.0%{\pm}8.9%$) compared with those younger than 10 years (n=45, $95.2%{\pm}3.3%$) (P=0.04). Multivariate analysis identified the mediastinal tumor site as the only independent prognostic factor. Conclusion: The prognosis of children with extracranial GCTs was favorable. However, nongerminomatous mediastinal tumors were associated with poor survival in children. Further research is needed to improve the prognosis of children with malignant mediastinal GCTs.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.7
• /
• pp.2819-2826
• /
• 2015

Combinations of multiple biomarkers representing distinct aspects of metastasis may have better prognostic value for breast cancer patients, especially those in late stages. In this study, we evaluated the protein levels of N-${\alpha}$-acetyltransferase 10 protein (Naa10p), synuclein-${\gamma}$ (SNCG), and phosphatase of regenerating liver-3 (PRL-3) in 365 patients with breast cancer by immunohistochemistry. Distinct prognostic subgroups of breast cancer were identified by combination of the three biomarkers. The Naa10p+SNCG-PRL-3-subgroup showed best prognosis with a median distant metastasis-free survival (DMFS) of 140 months, while the Naa10p-SNCG+PRL-3+subgroup had the worst prognosis with a median DMFS of 60.5 months. Multivariate analysis indicated Naa10p, SNCG, PRL-3, and the TNM classification were all independent prognostic factors for both DMFS and overall survival (OS). The three biomarker combination of Naa10p, SNCG and PRL-3 performed better in patients with lymph node metastasis, especially those with more advanced tumors than other subgroups. In conclusion, the combined expression profile of Naa10p, SNCG and PRL-3, alone or in combination with the TNM classification system, may provide a precise estimate of prognosis of breast cancer patients.

• Journal of Gastric Cancer
• /
• v.14 no.3
• /
• pp.180-186
• /
• 2014

Purpose: At present, a human epidermal growth factor receptor 2 (HER2)-based concept of tumor biology has been established, and trastuzumab ($Herceptin^{(R)}$; Genentech/Roche, San Francisco, CA, USA), a monoclonal humanized antibody directed against HER2, is a pivotal agent for the management of HER2 positive (HER2+) metastatic breast cancer. It is also known that HER2 has a predictive value in gastric cancer; however, its association with the prognosis of this disease remains uncertain. The purpose of this study was to evaluate both the relationship between HER2 overexpression in the tumors of gastric cancer patients, and the prognosis of these patients who have had curative resection. Materials and Methods: A total of 139 consecutive patients with gastric cancer who underwent surgery at the Kosin University Gospel Hospital between October 2011 and March 2012 were included in this retrospective study. All tumor samples were examined for HER2 expression by immunohistochemistry. A retrospective review of the medical records was conducted to determine the correlation between the presence of HER2 overexpression and clinicopathological factors. Results: The HER2+ rate was 15.1%. HER2 overexpression was associated with histological grade (P=0.044) and Lauren classification (P=0.036). There was no significant difference in the 2-year overall survival between HER2+ and HER2- patients (P=0.396). Multivariate analysis showed that HER2 was not an independent prognostic factor. Conclusions: HER2 overexpression in tumors was associated with histological grade and Lauren classification in gastric cancer patients with curative resection. However, HER2 was not an independent prognostic factor for gastric cancer in our study.