• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.11
• /
• pp.1657-1662
• /
• 2017

Rotor bar faults in induction machines, which are a part of main distribution of power system, can even stop the entire system by causing contact between a stator and a rotor. There are two methods of diagnosing rotor bar faults in induction motors, online and offline tests, and existing diagnosis methods have many limitations which can lead to misdiagnosis. This paper proposes a potable rotor bar faults diagnosis system based on single phase rotation test, one of offline test methods, which detects rotor bar faults through impedance interpretation by exciting AC current in a stator winding. The test was conducted on a motor of 0.4kW in the laboratory and a motor of 1500kW in industry field.

• Journal of Mechanical Science and Technology
• /
• v.19 no.8
• /
• pp.1670-1681
• /
• 2005

In-situ diagnosis of chiller performance is an essential step for energy saving business. The main purpose of the in-situ diagnosis is to predict the performance of a target chiller. Many models based on thermodynamics have been proposed for the purpose. However, they have to be modified from chiller to chiller and require profound knowledge of thermodynamics and heat transfer. This study focuses on developing an easy-to-use diagnostic technique that is based on adaptive neuro-fuzzy inference system (ANFIS). The effect of sample data distribution on training the ANFIS is investigated. It is found that the data sampling over 10 days during summer results in a reliable ANFIS whose performance prediction error is within measurement errors. The reliable ANFIS makes it possible to prepare an energy audit and suggest an energy saving plan based on the diagnosed chilled water supply system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.3
• /
• pp.244-251
• /
• 1997

In this paper, we propose a fault diagnosis algorithm to detect and isolate multiple faults in a system. The proposed fault diagnosis algorithm is based on a multiple fault classifier which consists of two ART2 NN(adaptive resonance theory2 neural network) modules and the algorithm is composed of three main parts - parameter estimation, fault detection and isolation. When a change in the system occurs, estimated parameters go through a transition zone in which residuals between the system output and the estimated output cross the threshold, and in this zone, estimated parameters are transferred to the multiple faults classifier for fault isolation. From the computer simulation results, it is verified that when the proposed diagnosis algorithm is performed successfully, it detects and isolates faults in the position control system of a DC motor.

• Nuclear Engineering and Technology
• /
• v.53 no.10
• /
• pp.3256-3263
• /
• 2021

The main steam line break accident is an essential initiating event of the pressurized water reactor. In present work, the fuzzy set theory and the signal-based fault detection method has been used to detect the occurrence and diagnosis of the location and break area for the small scale MSLB. The models are validated by the AP1000 accident simulator based on MAAP5. From the test results it can be seen that the proposed approach has a rapid and proper response on accident detection and location diagnosis. The method proposed to evaluate the break area shows good performances for small scale MSLB with the relative deviation within ±3%.

• Journal of Genetic Medicine
• /
• v.18 no.2
• /
• pp.83-93
• /
• 2021

Charcot-Marie-Tooth disease (CMT) is the most common hereditary motor and sensory peripheral neuropathy. CMT is usually classified into two categories based on pathology: demyelinating CMT type 1 (CMT1) and axonal CMT type 2 (CMT2) neuropathy. CMT1 can be distinguished by assessing the median motor nerve conduction velocity as greater than 38 m/s. The main clinical features of axonal CMT2 neuropathy are distal muscle weakness and loss of sensory and areflexia. In addition, they showed unusual clinical features, including delayed development, hearing loss, pyramidal signs, vocal cord paralysis, optic atrophy, and abnormal pupillary reactions. Recently, customized treatments for genetic diseases have been developed, and pregnancy diagnosis can enable the birth of a normal child when the causative gene mutation is found in CMT2. Therefore, accurate diagnosis based on genotype/phenotypic correlations is becoming more important. In this review, we describe the latest findings on the phenotypic characteristics of axonal CMT2 neuropathy. We hope that this review will be useful for clinicians in regard to the diagnosis and treatment of CMT.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.19 no.1
• /
• pp.44-51
• /
• 2023

The RCP is one of the main components in nuclear power plants and plays an important role in circulating coolant to the RCS system. Currently, nuclear plants are monitored using various monitoring systems. However, since they operate independently according to their functional purpose, it is not able to analyze vibration and operation/performance information comprehensively, and thus failure diagnosis accuracy is limited. In addition, these systems do not provide some important information (such as fault type, parts and cause) necessary for emergency actions, but provide only alarm information. To improve these technical problems, this study proposes a diagnosis technique (M/L, Rule-based model, Data-driven model, Narrow band model) and methodology for comprehensive analysis.

• Journal of Chest Surgery
• /
• v.57 no.2
• /
• pp.109-119
• /
• 2024

Varicose veins usually present in the superficial veins of the lower extremities and are one of the main clinical presentations of chronic venous disease (CVD). Patients' symptoms may vary according to the pathophysiology, location, and severity of CVD. The prevalence of CVD in Korea has been increasing gradually. However, due to its broad clinical spectrum and the subjective nature of its diagnosis using ultrasound, discrepancies in diagnostic and treatment quality may exist among treating physicians. There have been recent efforts to improve the quality of the diagnosis and treatment of varicose veins in Korea by standardizing the diagnostic criteria and the indications for treatment. This study is a comprehensive review of the clinical manifestations and diagnostic criteria of CVD based on the most recent international and domestic guidelines and reports.

• Journal of Veterinary Clinics
• /
• v.18 no.3
• /
• pp.273-278
• /
• 2001

Chronic mitral valvular insufficiency (CMVI) is the most common heart disease in dogs. The prevalence of CMVI is age-dependent. CMVI is usually affected to small to medium size breeds. It is more prevalent in males than females. The characteristic lesions of CMVI are caused by an acquired chronic structural degeneration of the mitral valve defined as endocardiosis or myxomatous degeneration. The main clinical signs are cough, respiratory distress, weakness and pleural effusion and ascites by secondary right-sided heart failure. The most prominent clinical finding is a systolic heart murmur. The thoracic radiography and echocardiography are useful methods in diagnosis of CMVI. Thoracic radiographic findings are left atrial enlargement, left main stem bronchial compression and pulmonary edema. Echocardiography is confirmed to increased left atrial and ventricular dimension, mitral regurgitation, mitral valve thickening and abnormal movement. Thoracic radiography and echocardiography are used to obtain a definite diagnosis of CMVI, and then to study the progression of the condition.

• Journal of Electrical Engineering and Technology
• /
• v.3 no.3
• /
• pp.293-299
• /
• 2008

One of the problems with the fault diagnosis of transformers based on dissolved gas is the inability to match the result of the different standards of fault diagnosis with real world standards. In this paper, the results of the different standards are analyzed using fuzzy logic and then compared with the empirical test. The proposed method is based on the standards and guidelines of the International Electrotechnical Commission (IEC), the Central Electric Generating Board (CEGB), and the American Society for Testing and Material (ASTM) and its main task is to assist the conventional gas ratio method. The comparison between the suggested method and existing methods indicates the capability of the suggested method in the on-line fault diagnosis of transformers. In addition, in some cases the existing standards are not able to diagnose the fault. For theses instances, the presented method has the potential of diagnosing the fault. In this paper, the information of three real transformers is used to show the capability of the suggested method in diagnosing the fault. The results validate the capability of the presented method in fault diagnosis of the transformer.

• Child Health Nursing Research
• /
• v.8 no.1
• /
• pp.44-54
• /
• 2002

The main purpose of this methodological study was to develop an assessment tool and intervention protocol for child and family with childhood cancer at early diagnosis stage. The assessment tool and intervention protocol was developed by extensive literature review and consultation with experts. Review of nine domestic and sixty-six international journal articles were done to identify stress, interventions, coping strategies and adjustment of children with cancer and their family. Results were as follows; First, assessment at the early diagnosis stage need to include information on patient, family, and patient/family attitude toward diagnosis and treatment. Second, intervention protocol for children with cancer includes control physical symptoms, manage the side effects of chemotherapy and diagnostic or therapeutic procedures, control emotional responses, provide support and information, assist decision-making and adjust to environment. Third, intervention protocol for family includes controlling emotional responses, provision of informations, inducing family support to patient, improving family cohesion, supporting siblings and supporting spiritual growth. In conclusion, the early diagnosis stage in cancer treatment is important for child and family since this stage greatly affects the overall adjustment of child and family to live with cancer. Therefore, pediatric nurses need to be sensitive to the need of patient/family and systematically manage their needs at this stage.