• Smart Structures and Systems
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• 제17권1호
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• pp.107-122
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• 2016

We propose an effective methodology using electromechanical impedance characteristics for estimating the remaining tensile force of tendons and simultaneously detecting damages of the anchorage blocks. Once one piezoelectric patch is attached on the anchor head and the other is bonded on the bearing plate, impedance responses are measured through these two patches under varying tensile force conditions. Then statistical indices are calculated from the impedances, and two types of relationship curves between the tensile force and the statistical index (TE Curve) and between statistical indices of two patches (SR Curve) are established. Those are considered as database for monitoring both the tendon and the anchorage system. If damage exists on the bearing plate, the statistical index of patch on the bearing plate would be out of bounds of the SR curve and damage can be detected. A change in the statistical index by damage is calibrated with the SR curve, and the tensile force can be estimated with the corrected index and the TE Curve. For validation of the developed methodology, experimental studies are performed on the scaled model of an anchorage system that is simplified only with 3 solid wedges, a 3-hole anchor head, and a bearing plate. Then, the methodology is applied to a real scale anchorage system that has 19 strands, wedges, an anchor head, a bearing plate, and a steel duct. It is observed that the proposed scheme gives quite accurate estimation of the remaining tensile forces. Therefore, this methodology has great potential for practical use to evaluate the remaining tensile forces and damage status in the post-tensioned structural members.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.947-952
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• 2006

It has been confirmed that the inner defect of insulator and the perfect diagnosis for aging are closely related to safe electric power transmission system and that the detection of accident and diagnosis technique turn out to be very important issues. But perfect diagnosis is difficult because discharge pattern is irregular. Thus, we investigated discharge pattern using the new distribution statistical models with cross-inked polyethylene(XLPE) specimens. Voltage was applied to power frequency by step method, and calibration of discharge was set to 50 pC. After the voltage was applied, it measured the discharge occurring during 10s. We investigated discharge pattern using the K-means analysis and Weibull function. We also investigated variation of centroid and shape parameter due to variation of voltage. As a result of analyzing K-means, it was confirmed that cluster including many object numbers was formed by the presence of void. And result of Weibull distribution, it was confirmed that shape parameter of discharge varied from 1.28 to 1.62 in no void specimens, and that shape parameter of discharge number varied from 1.28 to 1.62. In the void, shape parameter of discharge varied from 5.66 to 6.43, and shape parameter of discharge number varied from 5.05 to 5.08.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1306-1313
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• 2018

The randomness and incipient nature of certain faults in reactor systems warrant a robust and dynamic detection mechanism. Existing models and methods for fault diagnosis using different mathematical/statistical inferences lack incipient and novel faults detection capability. To this end, we propose a fault diagnosis method that utilizes the flexibility of data-driven Support Vector Machine (SVM) for component-level fault diagnosis. The technique integrates separately-built, separately-trained, specialized SVM modules capable of component-level fault diagnosis into a coherent intelligent system, with each SVM module monitoring sub-units of the reactor coolant system. To evaluate the model, marginal faults selected from the failure mode and effect analysis (FMEA) are simulated in the steam generator and pressure boundary of the Chinese CNP300 PWR (Qinshan I NPP) reactor coolant system, using a best-estimate thermal-hydraulic code, RELAP5/SCDAP Mod4.0. Multiclass SVM model is trained with component level parameters that represent the steady state and selected faults in the components. For optimization purposes, we considered and compared the performances of different multiclass models in MATLAB, using different coding matrices, as well as different kernel functions on the representative data derived from the simulation of Qinshan I NPP. An optimum predictive model - the Error Correcting Output Code (ECOC) with TenaryComplete coding matrix - was obtained from experiments, and utilized to diagnose the incipient faults. Some of the important diagnostic results and heuristic model evaluation methods are presented in this paper.

• Journal of Trauma and Injury
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• 제22권2호
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• pp.212-217
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• 2009

Purpose: To analyze delayed diagnosis, we collected date on pediatric and adolescent patients who had been admitted to the Emergency Department with injuries due to minor trauma Methods: We retrospectively analyzed the age distribution, trauma mechanism, time interval for each affected body region at delayed diagnosis, hospital stay, and outcome for 161 pediatric and adolescent patients who had been admitted to the Emergent Department of Gachon University Gil Hospital from January 2006 to September 2008. Results: The incidence of delayed diagnosis in pediatric and adolescent trauma was 11.8% in our retrospective review of 161 pediatric and adolescent patients. Lengths of hospitalization were longer in patients with delayed diagnosis (p<0.05). Patients with delayed diagnosis were more often transferred to other hospitals than patients with non-delayed diagnosis (p<0.05). The time intervals for each different affected body regions at delayed diagnosis were significantly different, but the hospital stays were not. There were no statistical significance to age on affected body region. Conclusion: From this study, we found that admission result and hospital stay were statistically significant differences between the delayed-diagnosis patient group and the non-delayed-diagnosis patient group. Finally, we must follow up pediatric and adolescent patients with minor trauma, closely considering missed injuries.

• 대한한의진단학회지
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• 제13권2호
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• pp.88-116
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• 2009

Background : EBM (the evidence based medicine) is the direction of the development for oriental medicine. The pulse meter-analyzer is the important part to standardize the pulse diagnosis. When we set up the direction of the study on the pulse meter-analyzer, the awereness about the pulse meter and analyzer of the clinical oriental medical doctors as consumers is very important. Objectives : In order to prepare for the mutual study and the export strategy on the pulse meter-analyzer of Korea and China, the attitude of the study and the grasp of the awereness about the pulse meter-analyzer of the Chinese medical doctors are very important. Methods : We developed the several items as the important factor of the development of the pulse meter and analyzer. They were translated by chinese medical doctor. The investigation for demend was conducted during 3 months in Guangzhou City, Guangdong Province, China. The results of the investigation was done the statistical method of frequency analysis, Chi-squared test, correspondence analysis. Results : The most important differentiation of symptom is the symptom of JANG-BU(臟腑). The method of the utility in the pulse diagnosis is Chon-Gu (寸口) pulse diagnosis and the research on Chon-Kwan-Cheok(寸關尺) is the most important measurement factor. And the typical the old pulse is the little-fine weak pulse. The pulse meter-analyzer is most suitable to the diagnosis of the hypertension and the arteriosclerosis. Conclusion : The development of the pulse analyzer including the requests of Korean and Chinese medical doctors is very important. Specially the researches on the influence factors of the traditional diagnosis and the environment of the measurement are important for developing the pulse analyze.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제19권4호
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• pp.229-235
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• 2016

Purpose: To study whether breastfeeding and breastfeeding status during gluten introduction influences the age at diagnosis of celiac disease (CD). In addition to study, whether the timing of gluten introduction influences the age at diagnosis of CD. Methods: It was a hospital based observational study. Total 198 patients diagnosed with CD as per modified European Society of Pediatric Gastroenterology, Hepatology and Nutrition (2012) criteria, aged between 6 months to 6 years were included. Detail history taken with special emphasis on breastfeeding and age of gluten introduction. Standard statistical methods used to analyze the data. Results: $Mean{\pm}standard$ deviation age of onset and diagnosis of CD in breastfed cases was $2.81{\pm}1.42$ years and $3.68{\pm}1.55$ years respectively as compared to $1.84{\pm}1.36$ years and $2.70{\pm}1.65$ years respectively in not breastfed cases (p<0.05). Those who had continued breastfeeding during gluten introduction and of longer duration had significantly delayed onset of disease. The age at onset of CD was under one year in 40.42% of the cases, who had started gluten before 6 months of age compared to only 12.58% of those who had started gluten later (p<0.001). The proposed statistical model showed that two variables, i.e., breast feeding status during gluten introduction and age at gluten introduction positively influencing the age at diagnosis of CD. Conclusion: Delayed gluten introduction to infant's diet along with continuing breastfeeding, delays symptomatic CD. However, it is not clear from our study that these infant feeding practices provide permanent protection against the disease or merely delays the symptoms.

• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3031-3035
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• 2012

Background: Though open surgical biopsy is the procedure of choice for the diagnosis of bone tumors, many disadvantages are associated with this approach. The present study was undertaken to evaluate the role of fine needle aspiration cytology (FNAC) as a diagnostic tool in cases of bony tumors and tumor-like lesions which may be conducted in centers where facilities for surgical biopsies are inadequate. Methods: The study population consisted of 51 cases presenting with a skeletal mass. After clinical evaluation, radiological correlation was done to assess the nature and extent of each lesion. Fine needle aspiration was performed aseptically and smears were prepared. Patients subsequently underwent open surgical biopsy and tissue samples were obtained for histopathological examination. Standard statistical methods were applied for analysis of data. Results: Adequate material was not obtained even after repeated aspiration in seven cases, six of which were benign. Among the remaining 44 cases, diagnosis of malignancy was correctly provided in 28 (93.3%) out of 30 cases and categorical diagnosis in 20 (66.67%). Interpretation of cytology was more difficult in cases of benign and tumor-like lesions, with a categorical opinion only possible in seven (50%) cases. Statistical analysis showed FNAC with malignant tumors to have high sensitivity (93.3%), specificity (92.9%) and positive predictive value of 96.6%, whereas the negative predictive value was 86.7%. Conclusion: FNAC should be included in the diagnostic workup of a skeletal tumor because of its simplicity and reliability. However, a definitive pathologic diagnosis heavily depends on compatible clinical and radiologic features which can only be accomplished by teamwork. The cytological technique applied in this study could detect many bone tumors and tumor-like conditions and appears particularly suitable as a diagnostic technique for rural regions of India as other developing countries.

• 대한세포병리학회지
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• 제18권1호
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• pp.55-61
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• 2007

Once diagnosed as "cell paucity"or "atypia" by the cytospin (CS) preparation, this CS preparation does not secure a precise diagnosis by repeated testing alone. Although the ThinPrep (TP) preparation is acknowledged to show increased cellularity, performing the screening tests for the cases that have enough cellularity, according to CS, raises issues for the cost-effectiveness. To obtain a more precise diagnosis through increasing the cellularity by performing TP, we selected the cases that were diagnosed as "cell paucity" or "atypia" by CS, but they required a more precise diagnosis, and the samples were processed via both CS and TP to compare the results. 11 patients diagnosed as "cell paucity" and 22 patients diagnosed as "atypia" by CS participated in this study. When the detection rate of atypical cells in both preparations with repeated urine cytology was compared, the overall detection rate of TP (16cases, 48.5%) was superior than that of CS (11cases, 33.3%), with statistical significance. The cellularity of both preparations was compared on repeated urine cytology; the general cellularity of TP (29cases, 87.9%) was higher than that of CS (20cases, 60.6%), but there was no statistical significance. Particularly, we repeated the TP for the 1 case that was diagnosed as "atypia" and we performed polyoma virus immunohistochemical staining, which confirmed polyoma virus. In conclusion, we can avoid obtaining negative diagnosis from cases with uncertain "atypia" or "cell paucity" by performing repeated TP testing.

• 한국산학기술학회논문지
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• 제19권3호
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• pp.40-45
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• 2018

생산 공정의 다변량 데이터에 기반한 지능적 공정 감시 및 진단 시스템은 조업의 안정성과 고품질의 제품을 달성하고 경쟁력을 유지하기 위해서는 필수적인 업무 중 하나로 간주되고 있는데, 이와 같은 추세는 공정 이상이 발생하는 경우 안정적이고 경제적인 조업에 큰 영향을 미치는 것에 기인한다. 본 연구에서는 다변량 공정 데이터에 기반한 진단기법을 제시하고 이를 시뮬레이션 공정 데이터를 활용하여 그 성능을 평가하고자 한다. 또한 원 데이터의 전처리 과정의 유무와 비선형 방법론의 활용이 진단 성능에 마치는 영향을 시뮬레이션 공정에서 제시된 15개의 공정 이상에 대해 평가하였다. 그 결과 제안된 방법론이 신뢰할 만한 결과를 주었으며 다른 비교 방법론인 전처리 과정이 없거나 선형 방법론을 사용한 타 방법론 대비 우월한 성능을 보여주었다. 제시된 방법론은 공정 데이터에 기반한 방법론으로서 공정에 대한 수학적 모델이나 지식 모델에 비하여 상대적으로 모델링이 간편하며 공정 데이터의 잡음에 강건하다는 장점을 가진다.

• Transactions on Electrical and Electronic Materials
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• 제11권1호
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• pp.42-47
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• 2010

Polymer insulating materials such as cross linked polyethylene (XLPE) are employed in electric cables used for extra high voltage. These materials can degrade due to chemical, mechanical and electric stress, possibly caused by voids, the presence of extrinsic materials and protrusions. Therefore, this study measured discharge patterns, discharge phase angle, quantity and occurrence frequency as well as changes in XLPE under different temperatures and applied voltages. To quantitatively analyze the irregular partial discharge patterns measured, the discharge patterns were examined using a statistical program. A three layer sample was fabricated, wherein the upper and lower layers were composed of non-void XLPE, while the middle layer was composed of an air void and copper particles. After heating to room temperature and $50^{\circ}C$ and $80^{\circ}C$ in silicone oil, partial discharge characteristics were studied by increasing the voltage from the inception voltage to the breakdown voltage. Partial discharge statistical analysis showed that when the K-means clustering was carried out at 9 kV to determine the void discharge characteristics, the amount discharged at low temperatures was small but when the temperature was increased to $80^{\circ}C$, the discharge amount increased to be 5.7 times more than that at room temperature because electric charge injection became easier. An analysis of the kurtosis and the skewness confirmed that positive and negative polarity had counterclockwise and clockwise clustering distribution, respectively. When 5 kV was applied to copper particles, the K-means was conducted as the temperature changed from $50^{\circ}C$ to $80^{\circ}C$. The amount of charge at a positive polarity increased 20.3% and the amount of charge at a negative polarity increased 54.9%. The clustering distribution of a positive polarity and negative polarity showed a straight line in the kurtosis and skewness analyses.