• Design & Manufacturing
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• v.17 no.1
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• pp.27-32
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• 2023

In this paper, we intend to predict the mass of the spiral using CAE and machine learning. First, We generated 125 data for the experiment through a complete factor design of 3 factors and 5 levels. Next, the data were derived by performing a molding analysis through CAE, and the machine learning process was performed using a machine learning tool. To select the optimal model among the models learned using the learning data, accuracy was evaluated using RMSE. The evaluation results confirmed that the Support Vector Machine had a good predictive performance. To evaluate the predictive performance of the predictive model, We randomly generated 10 non-overlapping data within the existing injection molding condition level. We compared the CAE and support vector machine results by applying random data. As a result, good performance was confirmed with a MAPE value of 0.48%.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7061-7064
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• 2014

Background: To assess the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of intraoperative gross examination (IGE) of uterine specimens in determining deep myometrial invasion and cervical invasion compared to final histology. Materials and Methods: The clinical, surgical and histological data of all FIGO stage I-II endometrial cancer (EC) patients who had primary surgery were reviewed. Results of the IGE for myometrial invasion and cervical invasion were compared to the final histology. The sensitivity, specificity, PPV, NPV, and accuracy of the IGE in determining deep myometrial invasion and cervical invasion were calculated. Association between clinico-pathological factors and discrepancy between IGE and final histology in the determination of myometrial invasion was also assessed. A p-value of <0.05 was considered significant. Results: From January 2007 to December 2012, 179 patients diagnosed with clinical stage I-II endometrial cancer underwent surgical staging. The sensitivity and specificity of IGE in detecting deep myometrial invasion were 42.4% and 90.0%, respectively, and the PPV and NPV were 67.6% and 76.1%. The overall accuracy of IGE was 74.3%. The sensitivity and specificity of IGE in identifying cervical invasion were 28.6% and 97.5%, respectively, while the PPV and NPV were 60.0% and 91.1%. The overall accuracy of IGE was 89.4%. Conclusions: The sensitivity of IGE for detecting deep myometrial invasion and cervical invasion in early-stage EC is too low to be used alone. Alternative methods including intraoperative frozen section analysis, preoperative three dimensional ultrasound, and preoperative magnetic resonance imaging should be strongly considered.

• Korean Journal of Radiology
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• v.22 no.7
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• pp.1203-1212
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• 2021

Objective: To investigate the diagnostic accuracy and complications of cone-beam CT-guided percutaneous transthoracic needle biopsy (PTNB) of juxtaphrenic lesions and identify the risk factors for diagnostic failure and complications. Materials and Methods: In total, 336 PTNB procedures for lung lesions (mean size ± standard deviation [SD], 4.3 ± 2.3 cm) abutting the diaphragm in 326 patients (189 male and 137 female; mean age ± SD, 65.2 ± 11.4 years) performed between January 2010 and December 2014 were included. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the PTNB procedures for the diagnosis of malignancy were measured based on the intention-to-diagnose principle. The risk factors for diagnostic failures and complications were evaluated using logistic regression analysis. Results: The accuracy, sensitivity, specificity, PPV, and NPV were 92.7% (293/316), 91.3% (219/240), 91.4% (74/81), 96.9% (219/226), and 77.9% (74/95), respectively. There were 23 diagnostic failures (7.3%), and lesion sizes ≤ 2 cm (p = 0.045) were the only significant risk factors for diagnostic failure. Complications occurred in 98 cases (29.2%), including 89 cases of pneumothorax (26.5%) and 7 cases of hemoptysis (2.1%). The multivariable analysis showed that old age (> 65 years) (p = 0.002), lesion size of ≤ 2 cm (p = 0.003), emphysema (p = 0.006), and distance from the pleura to the target lesion (> 2 cm) (p = 0.010) were significant risk factors for complications. Conclusion: The diagnostic accuracy of cone-beam CT-guided PTNB of juxtaphrenic lesions for malignancy was fairly high, and the target lesion size was the only significant predictor of diagnostic failure. Complications of cone-beam CT-guided PTNB of juxtaphrenic lesions occurred at a reasonable rate.

• Clinical Endoscopy
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• v.56 no.3
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• pp.325-332
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• 2023

Background/Aims: Administrative databases provide valuable information for large-cohort studies. This study aimed to evaluate the diagnostic accuracy of an administrative database for resected gastric adenomas. Methods: Data of patients who underwent endoscopic resection for benign gastric lesions were collected from three hospitals. Gastric adenoma cases were identified in the hospital database using International Classification of Diseases (ICD) 10-codes. The non-adenoma group included patients without gastric adenoma codes. The diagnostic accuracy for gastric adenoma was analyzed based on the pathological reports of the resected specimen. Results: Among 5,095 endoscopic resections with codes for benign gastric lesions, 3,909 patients were included in the analysis. Among them, 2,831 and 1,078 patients were allocated to the adenoma and non-adenoma groups, respectively. Regarding the overall diagnosis of gastric adenoma with ICD-10 codes, the sensitivity, specificity, positive predictive value, and negative predictive value were 98.7%, 88.5%, 95.2%, and 96.8%, respectively. There were no significant differences in these parameters between the tertiary and secondary centers. Conclusions: Administrative codes of gastric adenoma, according to ICD-10 codes, showed good accuracy and can serve as a useful tool to study prognosis of these patients in real-world data studies in the future.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1168-1177
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• 2015

This paper presents a scheme to improve the line current distortion of power factor corrector (PFC) topology at the zero crossing point using a predictive control algorithm in both the continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The line current in single-phase PFC topology is distorted at the zero crossing point of the input AC voltage because of the characteristic of the general proportional integral (PI) current controller. This distortion degrades the line current quality, such as the total harmonic distortion (THD) and the power factor (PF). Given the optimal duty cycle calculated by estimating the next state current in both the CCM and DCM, the proposed predictive control algorithm has a fast dynamic response and accuracy unlike the conventional PI current control method. These advantages of the proposed algorithm lower the line current distortion of PFC topology. The proposed method is verified through PSIM simulations and experimental results with 1.5 kW bridgeless PFC (BLPFC) topology.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2631-2633
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• 2005

In this paper, we propose a new discrete-time predictive current controller for a PMLSM(permanent magnet linear synchronous motor). The main objectives of the current controllers are that the measured stator current is tracked the command current value accurately and the transient interval is shorten as much as possible, in order to obtain high-performance of ac drive system. The conventional predictive current controller is hard to implement in full digital current controller since a finite calculation time causes a delay between the current sensing time and the time that take to apply the voltage to motor. A new control strategy is the scheme that gets the fast adaptation of transient current change, the fast transient response tracking. Moreover, the simulation results will be verified the improvements of predictive controller and accuracy of the current controller.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.4
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• pp.367-374
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• 2007

Purpose: The diagnostic relevancies and characteristics and of clinical methods in the diagnosis of internal derangement(ID) were tested by comparing the results of them with those of magnetic resonance imaging(MRI). Methods: 75 patients(150 temporomandibular joints; TMJs), who were suspected to have ID by clinical diagnoses, were included. Clinical diagnoses including mouth opening pathway and TMJ sound were conducted and MRI takings were done. Accuracies, sensitivities, specificities, positive predictive values, and negative predictive values of clinical diagnosis, mouth opening pathway, and TMJ sound were calculated by comparing with diagnoses with MRIs. Results: Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of clinical diagnosis were 59.3%, 83%, 49%, 81%, and 51%. They were 59%, 82%, 25%, 73%, and 35% for mouth opening pathways. Although deviation was somewhat accurate for representing disc displacement with reduction(ADDWR), other discrepancies on opening pathways were not clinically relevant. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of clicking sounds were 85%, 49%, 78%, 85%, and 37%. TMJs with crepitus were only three. But all TMJs with crepitus were diagnosed to have disc displacement without reduction(ADDWOR). Conclusion: When compared with diagnoses with MRIs, clinical diagnoses for ID were not so accurate. But they were suitable for screening tests for ID. Opening pathways and TMJ sounds were not so relevant in the diagnoses of IDs and so it was concluded that considerations for other factors must be included in the diagnoses of IDs.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.707-712
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• 2015

Background: To evaluate use of magnetic resonance imaging (MRI) and a logistic model including risk factors for lymph node metastasis for improved diagnosis. Materials and Methods: The subjects were 176 patients with rectal cancer who underwent preoperative MRI. The longest lymph node diameter was measured and a cut-off value for positive lymph node metastasis was established based on a receiver operating characteristic (ROC) curve. A logistic model was constructed based on MRI findings and risk factors for lymph node metastasis extracted from logistic-regression analysis. The diagnostic capabilities of MRI alone and those of the logistic model were compared using the area under the curve (AUC) of the ROC curve. Results: The cut-off value was a diameter of 5.47 mm. Diagnosis using MRI had an accuracy of 65.9%, sensitivity 73.5%, specificity 61.3%, positive predictive value (PPV) 62.9%, and negative predictive value (NPV) 72.2% [AUC: 0.6739 (95%CI: 0.6016-0.7388)]. Age (<59) (p=0.0163), pT (T3+T4) (p=0.0001), and BMI (<23.5) (p=0.0003) were extracted as independent risk factors for lymph node metastasis. Diagnosis using MRI with the logistic model had an accuracy of 75.0%, sensitivity 72.3%, specificity 77.4%, PPV 74.1%, and NPV 75.8% [AUC: 0.7853 (95%CI: 0.7098-0.8454)], showing a significantly improved diagnostic capacity using the logistic model (p=0.0002). Conclusions: A logistic model including risk factors for lymph node metastasis can improve the accuracy of MRI diagnosis of rectal cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1583-1588
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• 2012

Fine needle aspiration (FNA) cytology is well accepted as a safe, reliable, minimal invasive and cost-effective method for diagnosis of salivary gland lesions. This study evaluated the accuracy and diagnostic performance of FNA cytology in Thailand. A consecutive series of 290 samples from 246 patients during January 2001-December 2009 were evaluated from the archive of the Anatomical Pathology Department of our institution and 133 specimens were verified by histopathologic diagnoses, obtained with material from surgical excision or biopsy. Cytologic diagnoses classified as unsatisfactory, benign, suspicious for malignancy and malignant were compared with the histopathological findings. Among the 133 satisfactory specimens, the anatomic sites were 70 (52.6%) parotid glands and 63 (47.4 %) submandibular glands. FNA cytological diagnoses showed benign lesions in 119 cases (89.5 %), suspicious for malignancy in 3 cases (2.2 %) and malignant in 11 cases (8.3%). From the subsequent histopathologic diagnoses, 3/133 cases of benign cytology turned out to be malignant lesions, the false negative rate being 2.2 % and 1/133 case of malignant cytology turned out to be a benign lesion, giving a false positive rate was 0.8%. The overall accuracy, sensitivity, specificity, positive predictive value and negative predictive value were 97.0% (95% CI, 70.6%-99.4%), 81.3% (95% CI, 54.4%-96.0%), 99.1% (95% CI, 95.4%-100%), 92.9% (95% CI, 66.1%-99.8), 97.5% (95% CI, 92.8%-99.5%), respectively. This study indicated that FNA cytology of salivary gland is a reliable and highly accurate diagnostic method for diagnosis of salivary gland lesions. It not only provides preoperative diagnosis for therapeutic management but also can prevent unnecessary surgery.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7981-7984
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• 2014

Purpose: Colorectal cancer (CRC) screening with fecal occult blood testing (FOBT) has been associated with a reduction in CRC incidence and CRC-related mortality. However, a conventional FOBT requires stool collection and handling, which may be inconvenient for participants. The EZ-Detect$^{TM}$ (Siam Pharmaceutical Thailand) is a FDA-approved chromogen-substrate based FOBT which is basically a self-checked FOBT (no stool handling required). This study aimed to evaluate the accuracy of EZ-Detect for CRC detection. Methods: This prospective study was conducted in the Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand between November 2013 and May 2014. Some 96 patients with histologically-proven CRC and 101 patients with normal colonoscopic findings were invited to perform self-checked FOBT according to the manufacturer's instructions. Results were compared with endoscopic and pathologic findings. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CRC detection were calculated. Results: The present study revealed the sensitivity, specificity, PPV and NPV of this self-checked FOBT for CRC detection to be 41% (95% CI: 31-51), 97% (95% CI: 92-99), 93% (95% CI: 81-98) and 63% (95% CI: 55-70), respectively. The overall accuracy of the self-checked FOBT for identifying CRC was 70%. The sensitivity for CRC detection based on 7th AJCC staging was 29% for stage I, 32% for stage II and 50% for stage III/IV (P=0.19). The sensitivity was 33% for proximal colon and 42% for distal colon and rectal cancer (P=0.76). Notably, none of nine infiltrative lesions gave a positive FOBT. Conclusions: The self-checked FOBT had an acceptable accuracy of CRC detection except for infiltrative tumors. This home-administrated or 'DIY' do-it-yourself FOBT could be considered as one non-invasive and convenient tool for CRC screening.