• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.109-114
• /
• 1997

As CNC machine tool is one of core elements of manufacturing system, it is much important that it remains without troubleshoots. As a virtual machine is a recent alternative using IT for optimal utilization of CNC machine tool, it is a computer model that represents a CNC machine tool. But a virtual machine is still conceptual. So, in this paper, it is proposed that a virtual machine be a realistic model in the fault diagnosis module. For this purpose, the fault diagnosis system of machine tool using CORBA and fault diagnosis expert system has been implemented. Using this system, we have expections to diagnose exactly and prompty without the restriction of time or location, to reduce MTTR(Mean Time To Repair) and finally to increase the availability of manufacturing system.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.8 s.173
• /
• pp.182-191
• /
• 2005

It is very important to obtain a high quality of bone image for an accurate ultrasonic measurement of bone mineral density. In this study, we suggested a technique to acquire an optimal image by adapting an acoustic lens and a properly selected ultrasonic probe. Also, we have applied an image processing algorithm with which automatically makes a decision of brightness and contrast of image by generating threshold level, a composition of ultrasonic data, an elimination of noise using modified median filter, and a real time interpolation. We could confirm much improved resolution of bone image with acoustic lens attached to the ultrasonic probe and with the image processing algorithm suggested in this study. Therefore, it became possible to precisely diagnose the osteoprosis using ultrasonic imaging technique.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.2
• /
• pp.253-259
• /
• 2006

There is few study which automatically diagnoses the fault from ship's monitored data. The bigger control and monitoring system is. the more important fault diagnosis and maintenance is to reduce damage caused by system fault. This paper proposes fault diagnosis system using a correlation analysis algorithm which is able to diagnose and forecast the fault from monitored data and is composed of fault detection knowledge base and fault diagnosis knowledge base. For all kinds of ship's engine room monitored data are classified with combustion subsystem, heat exchange subsystem and electric motor and pump subsystem, To verify capability of fault detection, diagnosis and prediction, FMS(Fault Management System) is developed by C++. Simulation by FMS is carried out with population data set made by the log book data of 2 months duration from a large full container ship of H shipping company.

• Progress in Medical Physics
• /
• v.3 no.1
• /
• pp.3-8
• /
• 1992

An attempt is made to diagnose cancer of eight persons' urine by measuring the areas of the characteristic proton NMR signals observed in most cancer urine other than by using the previously developed reagent. The results of the attempt show that the former and ther latter give respectively one false diagnosis and four false diagnoses out of the persons' urine tested.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.332-336
• /
• 1997

To order to remain competitive, a manufacturing company need to maintain the optimal condition of its manufacturing system. Machine tools as an important element of a manufacturing system comprises complex mechanical as well as electronic components. So, diagnosing the troubles of machine tools is tricky process which requires a lot of experience and knowledge. Since providing machine tool users with necessary serices at the right time is very difficult,a remote diagnosis system is to be regarded as a good alternative, with which users can diagnose and fix the machine troubles. This paper presents a method to implement a remote machine tool diagnosis system using the world wide web technology and backward reasoning expert system.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.253-256
• /
• 1997

In this study, we developed a portable device which monitors and analyzes a vibration signal happened to machines. This device is based on PDA which is smaller thant a palm of the hand, but it has powerful computing ability as much s a computer with 100MHz CPU and an operating system called Windows CE. As a preprocess for a diagnosis of a rotating machine, training artificial neural network based on PC is performed, and the device will diagnose the condition of a rotating machine using weight values as a result of the training ANN.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.8 s.173
• /
• pp.57-63
• /
• 2005

Development of a locomotive mechanism fer the capsule type endoscopes will largely enhance the ability to diagnose disease of digestive organs. In connection with it, most of researches have focused on an installable locomotive mechanism in the capsule. In this paper, it is introduced that the movement of a capsule type endoscope in digestive organ can be manipulated by magnetic force produced outside human body. Since the magnetic force is provided by permanent magnets, no additional power supply to the capsule is required. Using a robotic manipulator for locating the external magnet, the capsule motion control system can cover the whole human digestive organs. This study is particularly concentrated on dither motion effect to improve the mobility of capsule type endoscope. It was experimentally found out that the friction coefficient between the capsule and digestive organ can be remarkably reduced by superposing yawing or rolling dither motion on the translatory motion. In this paper, the experimental results obtained with the direction, amplitude and frequency of sinusoidal dither motion changed is reported.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.6
• /
• pp.10-16
• /
• 2004

The detection and analysis of chatter behaviour in endmilling is very complex and difficult so it is necessary to detect and diagnose this chatter phenomenon clearly. This paper presents a new method for detecting the abnormal chatter in endmilling operation, based on the wavelet transform. Using AR spectrum the data that has chatter phenomenon was verified and the fundamental property of chatter and its characteristics in endmilling by using the wavelet transform is reviewed. This result obtained by wavelet transform proves the possibility and reliability of detecting the chatter in endmilling operation.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.29 no.1
• /
• pp.19-23
• /
• 2018

Ultrasonography has increasingly moved from being a modality confined to the radiology department to an active diagnostic and therapeutic aid available to the head and neck at the point of patient care. However, the application of ultrasonography to the laryngeal disorder is very rare due to progressive age-related ossification of laryngeal cartilage and the presence of air in the lumen, which contribute to difficult conditions for transmission of the ultrasonic waves. The observation about the movements of larynx or surrounding structures is important to understand the physiology of phonation or swallowing and to diagnose the disease. Ultrasonography is a noninvasive and safe imaging technique that can be used to investigate the anatomic structures of the head and neck. Recently, the development of high-frequency ultrasonography makes it possible to apply the ultrasound in the evaluation of larynx.