• International Journal of Computer Science & Network Security
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• 제23권7호
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• pp.23-31
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• 2023

This article discusses the sabotage of loops of intruder alarm systems. Although loop alarm systems are now gradually being replaced by digital alarm systems, they are still significantly present in practice. This paper describes two experimentally verified techniques for sabotaging balanced loops. The first technique is based on the jump replacement of the balancing resistor by a fake resistor. The second technique is based on inserting a series-parallel combination of two rheostats into the loop. By alternately changing the resistance of these rheostats, a state is reached where the balancing resistor is shorted by the parallel rheostat and replaced by the series rheostat. Sabotage devices for both attacks are technically simple and inexpensive, so they can be made and used by an amateur. Owners of loop alarm systems should become find out about this threat.

• 한국전자통신학회논문지
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• 제18권5호
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• pp.919-926
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• 2023

본 논문에서는 주야간 움직임 감지 시스템 개발을 위한 주야간 촬영이 가능한 카메라 시스템을 구현하였다. 이를 위해 CMOS 이미지 센서는 물론 IR-LED를 이용하여 야간에도 선명한 영상 캡처가 가능하도록 설계하였다. 또한 칼라모델 분리를 통해 비교적 단순한 움직임 감지 알고리즘을 제안하였다. 칼라모델에서 H채널만 추출한 후, 영상을 블럭으로 나눈 다음 연속 프레임간의 평균 색상값을 이용하여 블록 매칭방식을 적용함으로써 움직임을 감지할 수 있다. 촬영 중 움직임이 감지되면 자동으로 경보음이 울리면서 화면을 캡처하여 PC에 저장할 수 있는 주야간 움직임 감지 시스템을 구현하였다.

• 전기전자학회논문지
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• 제19권2호
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• pp.160-167
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• 2015

We present an experimental implementation of the inexpensive microwave security sensor that can detect both static and slowly moving objects in cluttered environment. The prototype consists of a frequency-modulated continuous wave radar sensor, control board or computer and software. The prototype was tested in a cluttered indoor environment. In case of intrusion or change of environment the sensor will give an alarm, determine the location of new object, change in its location and can detect a slowly moving target. To make a low-cost unit we use commercially available automotive radar and own signal processing techniques for object detection and tracking. The intruder detection is based on a comparison between current 'image' in memory and 'no-intrusion' reference image. The main challenge is to develop a reliable technique for detection of a relatively low-magnitude object signals hidden in multipath clutter echo signals. Various experimental measurements and computations have shown the feasibility and performance of the system.