• KEPCO Journal on Electric Power and Energy
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• 제6권4호
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• pp.447-454
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• 2020

Since SF₆ gas was discovered in the early 1900s, it has been widely used as an insulation material for electrical equipment. While various indicators have been developed to diagnose oil-immersed transformers, there are still insufficient indicators for the diagnosis of gas-insulated transformers. When necessary, chemical diagnostic methods can be used for gas-insulated transformers. However, the field suitability and accuracy of those methods for transformer diagnosis have not been verified. In addition, since various types of decomposition gases are generated therein, it is also necessary to establish appropriate analysis methods to cover the variety of gases. In this study, a gas-insulated transformer was diagnosed through the analysis of decomposition gases. Reliability assessments of both simple analysis methods suitable for on-site tests and precise analysis methods for laboratory level tests were performed. Using these methods, a gas analysis was performed for the internal decomposition gases of a 154 kV transformer in operation. In addition, simulated discharge and thermal fault experiments were demonstrated. Each major decomposition gas generation characteristics was identified. The results showed that an approximate diagnosis of the inside of a gas-insulated transformer is possible by analyzing SO₂, SOF₂, and CO using simple analysis methods on-site. In addition, since there are differences in the types of decomposition gas generation patterns with various solid materials of the internal transformer, a detailed examination should be performed by using precise analysis methods in the laboratory.

• Journal of information and communication convergence engineering
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• 제6권2호
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• pp.207-212
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• 2008

There are several sensors in the liquid cargo ship. In the liquid cargo ship, we can get values from various sensors that are level sensor, temperature sensor, pressure sensor, oxygen sensor, VOCs sensor, high overfill sensor, etc. It is important to guarantee the reliability of sensors. In order to guarantee the reliability of sensors, we have to study the diagnosis of sensor fault. The technology of smart sensor is widely used. In this paper, the technology of smart sensor is applied to diagnosis of level sensor fault for liquid cargo ship. In order to diagnose sensor fault and find the sensor position, in this paper, we proposed algorithms of diagnosis of sensor fault using independent sensor diagnosis unit and self fault diagnosis using sensor modeling. Proposed methods are demonstrated by experiment and simulation. The results show that the proposed approach is useful. Proposed methods are useful to develop smart level sensor.

• 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.

• 대한후두음성언어의학회지
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• 제32권2호
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• pp.56-63
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• 2021

Laryngopharyngeal reflux disease (LPRD) is an inflammatory condition of the upper aerodigestive tract mucosa induced by reflux content from stomach. Some of vocal cord diseases are associated with laryngopharyngeal reflux. Because of the pathophysiological features, proton pump inhibitor shows therapeutic effect on some vocal cord diseases. As like that, the gastric reflux contents can make macroscopic or microscopic morphological changes in the upper aerodigestive tract mucosa. Although the pathophysiology of LPRD is relatively clear, clinical diagnosis is still difficult. The diagnosis of LPRD includes objective tests such as 24-hours multichannel intraluminal impedance-pH metry and subjective tests such as questionnaire method. However, the objective verification of reflux is difficult due to invasiveness of the method, and the questionnaire methods have limitations because many symptoms are not specific for LPRD. Moreover, most methods are not fully standardized until now. Despite these limitations, many researchers are struggling to standardize diagnosis and treatment of LPRD, and there are several new achievements recently. Therefore, the purpose of this article is to review the recent literature on the clinical presentation, diagnosis, and treatment of LPRD, and to systematize our knowledge.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2859-2870
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• 2022

Because nuclear power plants (NPPs) are safety-critical infrastructure, it is essential to increase their safety and minimize risk. To reduce human error and support decision-making by operators, several artificial-intelligence-based diagnosis methods have been proposed. However, because of the nature of data-driven methods, conventional artificial intelligence requires large amount of measurement values to train and achieve enough diagnosis resolution. We propose a graph neural network (GNN) based accident diagnosis algorithm to achieve high diagnosis resolution with limited measurements. The proposed algorithm is trained with both the knowledge about physical correlation between components and measurement values. To validate the proposed methodology has a sufficiently high diagnostic resolution with limited measurement values, the diagnosis of multiple accidents was performed with limited measurement values and also, the performance was compared with convolution neural network (CNN). In case of the experiment that requires low diagnostic resolution, both CNN and GNN showed good results. However, for the tests that requires high diagnostic resolution, GNN greatly outperformed the CNN.

• Journal of the Korean Data and Information Science Society
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• 제19권2호
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• pp.511-518
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• 2008

Medical diagnosis systems have been developed to make the knowledge and expertise of human experts more widely available, therefore achieving high-quality diagnosis. In this study, in order to support the diagnosis by the medical diagnosis system, we have preformed medical diagnosis inference three times: first by a neural network with the backpropagation algorithm, secondly by a discriminant analysis with all of the variables, and thirdly by a discriminant analysis with the selected variables. A discussion on comparison of these three methods has been provided.

• 대한한의학원전학회지
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• 제30권3호
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• pp.143-165
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• 2017

Objectives : The paper seeks to provide a study on Bianque's Pulse Diagnosis in the contexts of Huangdi Neijing's Maijing and Nanjing. Methods : The paper provides a comparison of sentences regarding Bianque's Pulse Diagnosis discovered in Neijing, Maijing, and Nanjing. Results & Conclusions: 1. Bianque's Pulse Diagnosis was given birth through stages in accoradnce with the development of Pyobonjin, Maeggujin, Gyeongmaeghyjin, and Meridian Theory. 2. It seems that Neijing filled in Sambuguhujin and In-yeongbuyangmaegjin because they were not discovered in Canggong's Records of Diagnosis. 3. Bianque's Pulse Diagnosis diagnosed death using Osaegjin. Underneath each sentence within each biography regarding Meridian, there existed Pulse dead Hou. 4. Bianque's Pulse Diagnosis quantified the operation and length of pulse in time. The concept of small net was added which led to the establishment of Fifty circulations, Yeongwi theory, Meridians circulation, and chongu's boundary.

• 품질경영학회지
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• 제52권2호
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• pp.357-376
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• 2024

Purpose: The purpose of this study is to design an objective and comparable diagnostic system for diagnosing the technology level of military maintenance depots and verify its actual applicability. Methods: Literature Review, Capability Maturity Model Integration, Analytic Hierarchy Process. Results: Military maintenance depot maintenance quality level diagnosis items, Maintenance quality level by maintenance technology area, Guidelines for diagnosing maintenance quality level, Quality level comparison results by area and implications for improvement. Conclusion: In order to systematically evaluate the maintenance quality of military maintenance depots, this study was conducted with the goal of designing an overall maintenance quality diagnosis system, including diagnosis areas, diagnosis items, and a diagnosis score award system, by improving the existing evaluation method. In addition, the newly developed maintenance quality diagnosis system was applied to actual evaluation activities and the results were returned to members, confirming the usefulness of the developed maintenance quality diagnosis system in the field.

• 대한한의진단학회지
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• 제9권1호
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• pp.47-58
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• 2005

Background and purpose: The purpose of this study is to review the recent 10 year Chinese achievements on the objectification of traditional pulse diagnosis in clinical area. Methods: From the China Journal Full Text Database (中國學術期刊全文數据庫) we searched papers on pulse diagnosis by the keyword 'Maizhen'(脈診) Resulls: The researches are summarized into four parts; (1) the researches on the normal pulse in the physiological state (2) the clinical researches of pulse diagnosis on the symptom and disease diagnosis (3) the clinical researches of pulse diagnosis on the acupuncture treatment (4) the application of pulse diagnosis on the functional evaluation of the athlete. Conclusion: The undoubted principles of the traditional pulse diagnosis are evaluated by the objective clinical researches. And the researchers are trying to find a new application area over the traditional one.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제14권2호
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• pp.122-129
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• 2011

The persistence of jaundice beyond the first 2 weeks of life require further investigation and this can be determined if the conjugated bilirubin levels are greater than 1.5 mg/dL or greater than 20% of the total bilirubin level. There is a diverse differential diagnosis for the cause of neonatal cholestasis due to hepatobiliary disease including biliary atresia, which eventually leads to liver cirrhosis if uncorrected before 60~80 days of life. Long-established initial studies include abdominal ultrasonography, hepatobiliary scintigraphy and liver biopsy, but better diagnostic methods are needed. Promising new options are described including MRCP (magnetic resonance cholangiography), ERCP (endoscopic retrograde cholangiography), and PCC (percutaneous cholecysto-cholangiography). Though no single test can differentiate biliary atresia from other neonatal cholestasis with confidence, a combination of diagnostic methods is usually consistently beneficial. By excluding biliary atresia as early as possible, the risk of unnecessary explolaparotomy with intraoperative cholangiography is decreased. Further evaluation would be required for the diagnosis of neonatal cholestasis after excluding biliary atresia.