• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.1B
• /
• pp.47-55
• /
• 2009

In recent network intrusion detection systems, regular expressions are used to represent malicious packets. In order to process incoming packets through high speed networks in real time, we should perform hardware-based pattern matching using the configurable device such as FPGAs. However, operating speed of FPGAs is slower than giga-bit speed network and so, multi-byte processing per clock cycle may be needed. In this paper, we propose a hardware architecture of multi-byte based regular expression pattern matching and implement the pattern matching circuit generator. The throughput improvements in four-byte based pattern matching circuit synthesized in FPGA for several Snort rules are $2.62{\sim}3.4$ times.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.5
• /
• pp.520-526
• /
• 2013

As the increasing of capacity and technology of power facilities, rotating machines are getting higher at capacity and voltage scale. Thus the monitoring and diagnosis of generators for fault detection has attracted intensive interest. In this paper, we developed fault diagnosis system for monitoring the fault operations in bad power systems. In order to verify the performance of this fault diagnosis system, we made the small scaled testing system which has the same winding structure of the real synchronous generator. The magnetic flux patterns in air-gap of a small-scale generator under various fault states as well as a normal state are tested by hall sensors and the fault detection system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.6
• /
• pp.412-416
• /
• 2018

Most series arcs lead to electrical fires that cannot be interrupted by circuit breakers, because the arc's current is outside the breaker's operating range. In this paper, experiments were conducted on the detection and identification of series arcs to prevent electrical fires. Plugs and outlets specified in KS C 8305 were deteriorated to replicate arc faults commonly found in fields. The characteristics of series arcs resulting from various types of loose connections were determined by analyzing the frequency spectra and phase distributions of detected arc pulses. The results showed that the simulated arc defects used in this study were more similar to actual arc phenomena than the existing arc generator specified in UL 1699. In addition, loose connections, such as wire-wire, terminal-wire, and outlet-plug, can be identified by phases of $0^{\circ}$, $180^{\circ}$ and $360^{\circ}$, respectively. These phases can be detected by a band pass filter with a frequency range of 5~10 MHz, which can be used as the trip signal for circuit breakers.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.4
• /
• pp.839-847
• /
• 2016

Energy recovery battery testing systems (ERBTS) have been widely used in battery manufactures. All the ERBTS are connected in parallel which forms a special and complicated micro-grid system, which has the shortcomings of low energy recovery efficiency, complex grid-connected control algorithms issues for islanded detection, and complicated power circuit topology issues. To solve those shortcomings, a DC micro-grid system is proposed, the released testing energy has the priority to be reutilized between various testing system within the local grid, Compared to conventional scheme, the proposed system has the merits of a simplified power circuit topology, no needs for synchronous control, and much higher testing efficiency. The testing energy can be cycle-used inside the local micro-grid. The additional energy can be recovered to AC-grid. Numerous experimental comparison results between conventional and proposed scheme are provided to demonstrate the validity and effectiveness of the proposed technique.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.1
• /
• pp.1-9
• /
• 2009

In this paper, a 2.4 GHz doppler radar system consisting of a doppler radar sensor and a baseband module were designed to detect heart beat and respiration signal without direct skin contact. The doppler radar system emits RF signal of 2.4 GHz toward human chest, and then detects phase modulation of the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from I/Q channels of the doppler radar system are applied to the pre-processing circuit, the amplification circuit, and the offset circuit of the baseband module. The designed system was tested on mouse, rabbit and mankind, which have different range of heart rates and respiration signals, to evaluate detection accuracy of the system. ECG acquisition system and respiration transducer were used to generate the reference signal. In our experiments, a performance of detection were found to be high in the case that the subject stays still. In this paper, we confirmed that non-contact heart beat and respiration detection using the doppler radar has the possibility and limitation according to distance, cardiopulmonary activities, range of heart rates and respiration.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.592-595
• /
• 2004

This paper presents a study on the development of a multi-sensing inertial sensor with a single mechanical structure, which can be used both as a gyroscope and an accelerometer. The proposed MEMS gyro-accelerometer is designed to detect the angular rate and the acceleration at the same time using two separate detection circuits for one proof mass. In this study, the detection and signal processing circuit for an effective signal processing of different inertial measurements is designed, fabricated, and tested. The experimental results show that the performances of the gyro-accelerometer have resolutions of 1mg and 0.025deg/sec and nonlinearities of less than 0.5% for the accelerometer and the gyroscope, respectively, which are similar results with those of sensors with different structures and different detection circuits. The size of the sensor is reduced almost by 50% comparing with the sensors of separated proof mass.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.55 no.1
• /
• pp.21-25
• /
• 2006

This paper describes the novel control techniques design of VSC(Voltage Sag Corrector) for the purpose of power line quality enhancement. A fast detecting technique of voltage sag is implemented through the detection of instantaneous value on synchronous rotating do-reference frame. The first order digital filter is added in the detection algorithm to protect the insensitive characteristics against the noise. The relationship between the total detection time and cut-off frequency of the filter is described. The size of the capacitor bank used as the energy storage element is designed from the point of view of input/output energy with circuit analysis. Finally, the validity of the proposed scheme is proven through the simulated results.

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.2
• /
• pp.375-382
• /
• 2001

In this study, an adapted Turbo Coding Algorithm for reducing communication error of a fire detection system for marine vessels, especially image transmission via power lone. Because it is necessary that this system communicate larger and faster than previous method, this study carried out enhancement a decoding speed by adaptation CRC with Turbo Code Algorithm, improvement of metric method, and reduction of decoding delay by using of Center-to-Top method. And the results are as follows: (1) Confirmed that a Turbo Code is so useful methods for reducing communication error in lots of noise environments. (2)Proposed technology in this study speed increasing method of Turbo Coding Algorithm proves 2 times faster than normal Turbo Code and communication error reducing as well in the board made by VHDL software & chips ALTERA company.

• Journal of Advanced Marine Engineering and Technology
• /
• v.20 no.1
• /
• pp.31-36
• /
• 1996

In recent years, as the electonic industry has become more advanced, the LPM(Linear Pulse Motor) has appeared in a wide range of applications because of easier control, operation by open-loop control, high positioning accuracy, and retrieval of position or velocity data by the input pulses. In this study, we deal with the development of a position detection device attached to a hybrid LPM in our laboratory. Precise position detection signals could be sensed by the synchronous rectifier method from the LPM stator scale. In addition, we can keep the amplitude constant by using an AGC(Automatic Gain Control) circuit. Experimental results show that the position data is good enough to perform the LPM position control.

• Journal of electromagnetic engineering and science
• /
• v.5 no.1
• /
• pp.26-30
• /
• 2005

It is important to know phase offsets of PN(Pseudo Noise) sequences in spread spectrum communications since the acquisition is equivalent to making a phase offset between a receiving PN sequence and a PN sequence of local PN generator be identical. In this paper, a phase offset enumeration method for PN sequences with error detection, and its application to the synchronization are proposed. The phase offset enumeration for an n-tuple PN sequence and its error detection are performed when one period of the sequence is received. Once the phase offset of the receiving sequence is calculated, we can easily accomplish the synchronization by initializing shift registers of a local PN generator according to the phase offset value. The mean acquisition time performance of the proposed scheme was derived analytically. Since this synchronization scheme can be realized by using simple circuit and acquires very rapid acquisition in high SNR but shows performance degradation in low SNR, it can be especially useful in indoor and office environments.