• International Journal of Computer Science & Network Security
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• v.23 no.7
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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.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.919-926
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• 2023

In this paper, we implemented the surveillance camera system capable of day and night shooting. To this end, it is designed to capture clear images even at night using a CMOS image sensor as well as an IR-LED. In addition, a relatively simple motion detection algorithm was proposed through color model separation. Motions can be detected by extracting only the H channel from the color model, dividing the image into blocks, and then applying the block matching method using the average color value between consecutive frames. When motions are detected during filming, an alarm sounds automatically and a day and night motion detection system is implemented that can capture and save the event screen to a PC.

• Journal of IKEEE
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• v.19 no.2
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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.