• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.5
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• pp.485-490
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• 2004

This paper presents a new interpolation algorithm for measuring high resolution position information which is prepared to a nino servo control motor using analog quadrature encoder. In the past, there are large capacity of memory(ROM or RAM) and two high price and resolution A/D(Analog-to-Digital Converter) for sensing two quadrature signals from a analog sinusoidal encoder interpolation. But high resolution of position from sinusoidal encoder can be obtained by using only small capacity of memory, one A/D converter and comparator. Experimental results show that the proposed algorithm is useful for measuring high resolution position.

• Journal of Sensor Science and Technology
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• v.6 no.4
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• pp.280-289
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• 1997

The measure of motor speed using encoder is difficult to detect accurate speed and direction in very low speed because the intervals between an encoder pulse and pulse are long. So various speed estimation techniques were proposed to have the good dynamic performance in low speed. And direction detection is so important as speed measurement in very low speed. But because the conventional direction detection circuit check the direction only 1 time in 1 period of each encoder pulses, so it has long delayed detection time in very low speed, thus accurate detection of direction is difficult. In this paper, we propose a 2 way edge detection method which can detect at the rising and filling edge of each encoder pulses. So it can check the direction 4 times in 1 period of each encoder pulses. Therefore if we use proposed method, we can reduce the detection time as 1/4 than that of conventional circuit and can detect more accurate speed and direction. And computer simulation and experiment is performed to verify the perfomance and effect of proposed circuit and we analyze it's results by comparing with that of conventional circuit.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.452-459
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• 2019

In this paper, we describe a PCM encoder structure that can update the telemetry system parameters in real time. In the PCM encoder, an analog signal control unit for FPGA, flash memory, and sensor data acquisition was constructed. UART communication, analog signal control, flash memory control, and frame generation are possible through logic inside FPGA of PCM encoder. UART communication allows the PC to transmit parameter data to the PCM encoder, and flash memory is controlled to update the parameter of the telemetry system in real time and finally the frame is formed. Simulation and verification were performed to confirm whether the parameter data is updated in real time, and the proposed structure was used to construct a telemetry system with enhanced flexibility and convenience.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.4
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• pp.687-697
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• 2023

Botnets, whose attack patterns are becoming more sophisticated and diverse, are recognized as one of the most serious cybersecurity threats today. This paper revisits the experimental results of botnet detection using autoencoder, a semi-supervised deep learning model, for UGR and CTU-13 data sets. To prepare the input vectors of autoencoder, we create data points by grouping the NetFlow records into sliding windows based on source IP address and aggregating them to form features. In particular, we discover a simple power-law; that is the number of data points that have some flow-degree is proportional to the number of NetFlow records aggregated in them. Moreover, we show that our power-law fits the real data very well resulting in correlation coefficients of 97% or higher. We also show that this power-law has an impact on the learning of autoencoder and, as a result, influences the performance of botnet detection. Furthermore, we evaluate the performance of autoencoder using the area under the Receiver Operating Characteristic (ROC) curve.

• Journal of Advanced Navigation Technology
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• v.28 no.3
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• pp.315-322
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• 2024

In this paper, we proposes real-time operating system based PCM encoder for telemetry system that must transmit frames within a set time. In the case of large aircraft, the complexity of the system is increasing because a lot of state information is measured from each sensor and peripheral device. In addition, as the amount measurement data increases, the role of PCM encoder to transmit frames within a set time is becoming important. Existing encoder is inflexible when changing specifications or implementing additional features. Therefore, a design is needed to supplement this. We propose a PCM encoder design applying uC/OS-II. In order to confirm the validity, a simulation was performed to measure the execution time of the task to confirm the performance.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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• pp.76-85
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• 2007

An optical rotary encoder is easy to implement for automatic control applications. In particular, the output of the encoder has a digital form pulse, which is also easy to be connected to a popular digital controller. By using the encoder, there are various angular velocity detecting methods, M-, T-, and M/T-method. Each of them has a property of its own. They have common limitation that the angular velocity detection period is strongly subject to the destination velocity magnitude in case of ultimate low range. They have ultimate long detection period or cannot even detect angular velocity at near zero velocity. This paper proposes a dual encoder system with two encoders of normal resolution. The dual encoder system is able to keep detection period moderately at near zero velocity and even detects zero velocity within nominal period. It is useful for detecting velocity in case of changing rotational direction at which there occurs zero velocity. In this paper, various experimental results are shown for the dual encoder system validity.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.996-999
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• 2002

본 논문에서는 위치 센서인 엔코더를 이용하여 토로이달 SRM을 구동시, 각 상의 슬롯에 감긴 서치 코일에서 유기되는 전압 파형을 분석했으며, 그 유기전압을 이용해 회전자의 위치를 추적하는 방법을 제안하였다. 그리고 이 추적 방법을 토대로 엔코더 없이 서치코일만으로 위치를 검출하여 토로이달 SRM을 구동시키는 방법을 제안하였다. 엔코더를 사용하지 않고 서치 코일에서 특정지점을 검출하여 토로이달 6/4 SRM을 구동시켜 그 타당성을 검증하였다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.147-154
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• 2000

A new hardware compensation method reducing displacement measurement errors, caused by tilt of index scale in moire linear encoders, has been developed. In conventional moire linear encoders, the detectors are aligned perpendicular to the line of moire fringes this structure is very sensitive to an unwanted tilt of the gratings. In this paper, a newly designed grating, called a phase-modulated grating, is developed to compensate for non-orthogonal errors. By using the phase-modulated grating instead of a conventional index, it is possible to reduce non-orthogonal errors of moire linear encoders.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.439-440
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• 2008

모터의 정밀한 제어를 위해서 홀센서와 모터의 회전자 위치를 검출해내는 엔코더의 사용이 필수적이라 할 수 있다. 본 논문에서는 BLAC모터의 회전자 위치검출 방법으로 자석과 디지털 신호처리 칩을 이용하여 엔코더와 홀센선의 기능을 구현하였다. 이러한 방법의 장점은 기구적인 구조가 단순하여 저가로 구현할 수 있다는 것이다. 단순 2극 자석이 칩의 중심점을 축으로 회전하면 칩 중심 부위의 통합적 홀소자가 칩 표면 자기장을 전압으로 변환한다. 이 신호를 받아 DSP의 아날로그/디지털 변환 기능을 이용하여 절대각도 위치 정보를 검출해내어 기존의 엔코더 성능을 대치하는 연구과정을 본 논문에서 보였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.944-945
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• 2008

전동기를 제어하기 위한 속도를 검출하는 장치로 광학적 엔코더를 일반적으로 많이 사용하고 있으며 레졸바는 구조적으로 엔코더를 전동기에 장착하기가 어려운 경우에 사용하고 있다. 때문에 레졸바는 엔코더와 비교하여 가격면에서 불리하지만 회전자의 절대위치를 검출하기 때문에 자극의 위치를 기준으로 제어하는 경우에 유용하다. 본 연구는 레졸바에 의하여 전동기의 회전속도를 검출하는 방법으로 최소한의 하드웨어인 필터를 사용하고 프로그램에 의한 디지털방법의 속도검출기에 관한 것이다.