• Journal of Biomedical Engineering Research
• /
• v.16 no.2
• /
• pp.183-190
• /
• 1995

The use of ultrasound pulsed Doppler systems has become increasingly popular due to the advantages of easy measurements of blood velocity, volume blood blow, and irregularities of the circulatory system. However, the 2-D Doppler systems have several problems, such as range ambiguity, low signal to noise ratio, and slow frame rate. The mean frequency aliasing problem originating from the pulse repetition frequency is one of major limitations in pulsed Doppler systems. A conventional approach to resolve this problem is tracking the mean frequency close to and beyond the Nyquist frequency along the temporal axis. In this paper, a new concept of tracking the mean frequency along the spatial axis is proposed. The proposed technique is fault tolerant by nature and more suitable for multi gate and 2-D Doppler system than conventional methods.

• Proceedings of the Korean Society for Bioinformatics Conference
• /
• 2005.09a
• /
• pp.101-106
• /
• 2005

Recently, as the size of genetic knowledge grows faster, automated analysis and systemization into high-throughput database has become hot issue. One essential task is to recognize and identify genomic entities and discover their relations. However, ambiguity of name entities is a serious problem because of their multiplicity of meanings and types. So far, many effective techniques have been proposed to analyze documents. Yet, accuracy is high when the data fits the model well. The purpose of this paper is to design and implement a document classification system for identifying entity problems using text/data mining combination, supplemented by rich data mining algorithms to enhance its performance. we propose RTP ost system of different style from any traditional method, which takes fault tolerant system approach and data mining strategy. This feedback cycle can enhance the performance of the text mining in terms of accuracy. We experimented our system for classifying RB-related documents on PubMed abstracts to verify the feasibility.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.10
• /
• pp.969-974
• /
• 2010

In this paper, we propose a fault-tolerant controller for compensating measurement noise of feedback sensor. Because control systems operate via feedback sensor's signal, the measurement noise in sensor's signal results in performance degradation or even system failure. Therefore, control systems often demand on compensating measurement noise. Our controller is equipped with a compensator in order to reject or reduce the effect of measurement noise in feedback information. Our proposed method is verified via simulation and experiment for a Ball and Beam system.

• Proceedings of the KIEE Conference
• /
• 1987.07a
• /
• pp.216-220
• /
• 1987

A graphic display and operator console system is developed for monitoring the operation of power plant. It has multiprocessor structure using VME bus and common memory. The graphic monitoring system is applied to fault tolerant control system for enhancing reliability of boiler analog controller. As a result, it displays all the operating date as color graphic images with 14 pages. Moreover, it can transfer the operator commands to the other micro-processors through common memory.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.5
• /
• pp.1149-1159
• /
• 1998

This paper presents the Controllable Self-Checking(CSC) Checker at which can be used the Fault-Tolerant System with the redundancy. According to the critical level of output(of system), especially, it can be instructed the time if it has to check the output or not. We adop the deterministic test, performed on-line, to detect the faults with a minimal test set. The results show the Parity 2-rail checker(P-TRC) which is designed much simpler than the checker has the higher fault coverage than the existent checker.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.12
• /
• pp.2187-2192
• /
• 2006

This paper presents a method of constructing the universal multiple processing element unit(UMPEU) by De Bruijn Graph. The second method is as following. First, we propose transformation operators in order to construct the De Bruijn UMPEU using properties of graph. Second, we construct the transformation table of De Bruijn graph using above transformation operators. Finally we construct the De Bruijn graph using transformation table. The proposed UMPEU be able to construct the De Bruijn graph for any prime number and integer value of finite fields. Also the UMPEU is applied to fault-tolerant computing system, pipeline class. parallel processing network, switching function and its circuits.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.2 no.2
• /
• pp.81-89
• /
• 2001

Space systems are operating in a changing and uncertain space environment and are desired to have autonomous capability for long periods of time without frequent telecommunications from the ground station At the same time. requirements for new set of projects/systems calling for ""autonomous"" operations for long unattended periods of time are emerging. Since, by the nature of space systems, it is desired that they perform their mission flawlessly and also it is of extreme importance to have fault-tolerant sensor/actuator sub-systems for the purpose of validating science measurement data for the mission success. Technology innovations attendant on autonomous data validation and health monitoring are articulated for a growing class of autonomous operations of space systems. The greatest need is on focus research effort to the development of a new class of fault-tolerant space systems such as attitude actuators and sensors as well as validation of measurement data from scientific instruments. The characterization for the next step in evolving the existing control processes to an autonomous posture is to embed intelligence into actively control. modify parameters and select sensor/actuator subsystems based on statistical parameters of the measurement errors in real-time. This research focuses on the identification/demonstration of critical technology innovations that will be applied to Autonomous Spacecraft Health Monitoring/Data Validation Control Systems (ASHMDVCS). Systems (ASHMDVCS).

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.4
• /
• pp.101-110
• /
• 2004

Flight and Qualification Models of Single Board Computer (SBC), called On-Board Computer (OBC), for HAUSAT-l picosatellite, which is scheduled to launch on September, 2004 by Russian "Dnepr" launch vehicle, have been developed. The OBC of HAUSAT-1 has been designed with some improved features compared to other picosatellites. A multifunctional controller and up-to-date SPI (Serial Peripheral Interface) and 1-Wire interface are implemented to simplify the harness routing and to minimize the mass and size of OBC. The improved fault-tolerant architecture design methodology is incorporated in the HAUSAT-1 OBC to protect against space radiation environment. The functions of the OBC were fully tested and verified by the Electrical Test Bed (ETB) model. This paper is also addressing the environmental test results, such as random vibration and thermal vacuum tests.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.4
• /
• pp.1333-1341
• /
• 2010

The goal of this research is to enhance the maintenance and monitoring system of ship environment using sensor network. It is important to know the location information of sensor nodes to control the sensors and to obtain the sensor data from sensor network inside the ship. In this paper, we address the grouping and routing mechanism according to the relative distance of sensor nodes, based on LEACH and PEGASIS. We also consider the fault tolerant mechanism using the location information of sensor nodes.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.8
• /
• pp.730-740
• /
• 2000

The software rejuvenation method for highly available multiplex systems uses a pro-active fault-tolerant approach to handle system failures. The software rejuvenation prevents failures from occurring, while the previous methods recover from failures after happening. Especially, since the software aging proceeds fast in the software used for the multimedia mobile computing due to the loss of communications or data, the preventive method from failures using software rejuvenation can be used for the multimedia mobile computing. In this paper, according to the operational parameters such as rejuvenation period, rejuvenation time, failure rate and repair rate of the servers, number of running servers, duration of running time, and type of running modes, we calculate steady-state probabilities, downtime, availability, and cost of the multiplex systems using software rejuvenation method. We validate the closed-form solutions of the mathematical model by experiments based on various operational parameters and find that the software rejuvenation method can be adopted as preventive fault-tolerant technique. The failure rate and unstable rate of the servers are essential factors for the decision making of the rejuvenation policies.