• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.578-580
• /
• 2004

Substation facilities have become large and complex in the electric power systems. Development of condition monitoring and diagnosis techniques have been very important to improve the security of substation transformers. This paper presents a method to analyze the cause and the degree of aging of power transformers by Self organizing map(SOM). Dissolved gas data were non-linearly transformed by sigmoid function to make determination of SOM close to that of human. Potential of a failure and the degree of aging of a normal transformer are identified by using the proposed quantitative criterion. Furthermore, transformer aging is monitored by the proposed criterion for a set of transformers. To demonstrate the validity of the proposed method, a case study is performed and its results are presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.220-220
• /
• 2010

The beta-amyloid protein ($A_{\beta}$) is well known for main cause of Alzheimer disease (AD). Generally, detection of $A_{\beta}$ is carried out by using fluorescent material or DNA test, but these process is long time and expensive process. Therefore, in this research, we investigated the simple diagnosis method to detect the $A_{\beta}$ by using photo-transistor.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.127.2-127
• /
• 2001

A transformer is one of the most important elements in the power network. Transformer faults could cause costly repairs and be dangerous to personnel. To avoid this, its reliable operation has great significance and, therefore, the diagnosis system of the transformer is necessitated. The dissolved gas-in-oil analysis (DGA) is the worldwide popular method of detecting faults such as a hot spot or partial discharges inside the transformer. DGA, however, is not a reliable technique to identify aging phenomena and mechanical faults including insulation failure, inter-turn short, etc. To overcome the drawbacks of DGA, the transfer function method is used to identify effectively these kinds of the mechanical faults. The transformer has a unique transfer function independent of the shape of the input waveform, which can be evaluated through sweep test. This transfer function changes by winding ...

• Toxicological Research
• /
• v.30 no.2
• /
• pp.117-120
• /
• 2014

Uranium is toxic and radioactive traces of it can be found in natural water and soils. High concentrations of it in biological systems cause genetic disorders and diseases. For the in vivo diagnosis, micro and nano range detection limits are required. Here, an electrochemical assay for trace toxic uranium was searched using stripping voltammetry. Renewable and simplified graphite pencils electrode (PE) was used in a three-electrode cell system. Seawater was used instead of an electrolyte solution. This setup can yield good results and the detection limit was attained to be at $10{\mu}gL^{-1}$. The developed skill can be applied to organic liver cell.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.594-597
• /
• 2001

As many industrial systems become more complex, they become extremely difficult to diagnose the cause of failures. The subject of this paper is ECCS(Emergency Core Cooling System) part of PWR(Pressurized Water Reactor). This paper presents modeling and diagnoser construction of ECCS based on discrete event system theory. Also, this paper presents that the ECCS system is diagnosible in our approach.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.21 no.4
• /
• pp.361-364
• /
• 2018

Accessory hepatic lobe is noted as and considered a rare disease in children. It can manifest with various symptoms and complications depending on the location, volume, type and position of the disease as presented on a child. The patient presented as a 14-month-old girl who was seen with a notable hepatosplenomegaly and portal hypertension. A diagnosis was made after taking an extensive medical history, observation and radiological examinations. The formal diagnosis was a prehepatic portal hypertension associated with accessory hepatic lobe.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.3
• /
• pp.20-28
• /
• 2000

Air wiping technique is widely used because of easy and efficient coating control in present CGL The coating weight is controlled by nozzle header pressure. strip line speed, and the distance between strip and nozzle. Coating defects are resulted from the unbalance of these control factors and the inaccuracy of coating equipments. We investigates the main cause of coating defects, such as edge overcoating and coating deviation through various experiments. It is found that the edge overcoating is mainly come from nozzle lip type, and the coating deviation is caused by the unbalance of dynamic pressure.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1626-1630
• /
• 2007

This dissertation finds out trouble types and occurrence regions using the faulty statistics of nondestructive test items in rolling stock parts of the Seoul Metro and using mechanical test about defective and broken parts with broken surface observation, cutting examination about trouble region, hardness experiment and tensile test. Also this dissertation finds out cause of trouble and damage through observation of microscopic formation using metallurgical microscope and scanning electron microscope, residual stress measurement about welding parts and damage diagnosis about defective and broken parts. Moreover it will present the improved plan of nondestructive method about trouble and the removal method of defect and repair welding and find solutions of reliability in parts and preventive maintenance.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.27 no.2
• /
• pp.87-90
• /
• 2016

Cough, the most common symptom, encountered in the outpatient clinic can be caused by various underlying diseases. It defines as chronic cough that the duration of cough is more than 8 weeks with a normal chest X-ray findings. The cause of cough can be found out for more than 90% through the appropriate diagnostic approach and Upper airway cough syndrome, Asthma and Gastroesophageal reflex disease are the most common causes of disease to non-smokers. Chronic cough can be due to not one reason but various reasons and achieve good results by a systematic approach to diagnosis and a concrete treatment on the basis of the sufficient understanding of the underlying disease.

• Journal of Sensor Science and Technology
• /
• v.23 no.1
• /
• pp.1-6
• /
• 2014

In many medical image devices, dc noise often prevents normal diagnosis. In wireless capsule endoscopy systems, multipath fading through indoor wireless links induces inter-symbol interference (ISI) and indoor electric devices generate impulsive noise in the received signal. Moreover, dc noise, ISI, and impulsive noise are also found in optical fiber communication that can be used in remote medical diagnosis. In this paper, a blind signal processing method based on the biased probability density functions of constant modulus error that is robust to those problems that can cause error propagation in decision feedback (DF) methods is presented. Based on this property of robustness to error propagation, a DF version of the method is proposed. In the simulation for the impulse response of optical fiber channels having slowly varying dc noise and impulsive noise, the proposed DF method yields a performance enhancement of approximately 10 dB in mean squared error over its linear counterpart.