• Journal of IKEEE
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• v.25 no.4
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• pp.703-709
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• 2021

As drone technology advances, the risks of drones are increasing, then technology to detect drones is becoming important. In this thesis, it was verified that miniaturized and lightweighted active array antenna could be used for radar system to detect drones in reality. The transmit-receive module was designed in the form of tile-type to simplify interconnections between devices. The waveform generation module and the down conversion module were miniaturized to include in one body too. As a result of verifing the detection performance through test, it was confirmed that the detection range was over 3.7Km.

• The Journal of Korea Robotics Society
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• v.13 no.1
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• pp.45-54
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• 2018

This paper presents a vision-based fall detection system to automatically monitor and detect people's fall accidents, particularly those of elderly people or patients. For video analysis, the system should be able to extract both spatial and temporal features so that the model captures appearance and motion information simultaneously. Our approach is based on 3-dimensional convolutional neural networks, which can learn spatiotemporal features. In addition, we adopts a thermal camera in order to handle several issues regarding usability, day and night surveillance and privacy concerns. We design a pan-tilt camera with two actuators to extend the range of view. Performance is evaluated on our thermal dataset: TCL Fall Detection Dataset. The proposed model achieves 90.2% average clip accuracy which is better than other approaches.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1345-1347
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• 2008

This paper described a method of determining whether arcing is present in a low-voltage wiring system. We simulated the series arcing that generated in electrical loads and fabricated a arc detection module which can discriminate between normal and arcing state. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage and an active band-pass filter with a frequency of 4 kHz ${\sim}$ 8 kHz to detect series arc signals only. We tested an Incandescent lamp that was controlled by a dimmer and analysed. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage by 80 dB and an active band-pass filter with a frequency of 4 kHz to detect series arc signals only. From the experimental results, we could detect series arc signals without an influence of non-linear loads.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.4
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• pp.235-242
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• 2022

As ship condition inspection technology has been developed, research on collecting, analyzing, and diagnosing condition information has become active. In ships, related research has been conducted, such as analyzing, detecting, and classifying major hull failures such as cracks and corrosion using 2D and 3D data information. However, for geometric deformation such as indents and bulges, 2D data has limitations in detection, so 3D data is needed to utilize spatial feature information. In this study, we aim to detect hull structural deformation positions. It builds a specimen based on actual hull structure deformation and acquires a point cloud from a model scanned with a 3D scanner. In the obtained point cloud, deformation(outliers) is found with a combination of RANSAC algorithms that find the best matching model in the Octree data structure and dataset.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.4
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• pp.318-324
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• 2017

We introduced a stereo camera on the aircraft to detect flight objects and to estimate the 3D position of them. The Saliency map algorithm based on PCT was proposed to detect a small object between clouds, and then we processed a stereo matching algorithm to find out the disparity between the left and right camera. In order to extract accurate disparity, cost aggregation region was used as a variable region to adapt to detection object. In this paper, we use the detection result as the cost aggregation region. In order to extract more precise disparity, sub-pixel interpolation is used to extract float type-disparity at sub-pixel level. We also proposed a method to estimate the spatial position of an object by using camera parameters. It is expected that it can be applied to image - based object detection and collision avoidance system of autonomous aircraft in the future.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.206-209
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• 2000

Almost vision application systems use 2-D information by taking only one camera. Recently it arises to utilize 3-D information, which is distance from camera to object, because 2-D information is not sufficient. Therefore, we take stereo camera system. In motion detection algorithm using stereo vision, it operates like one camera system, which takes advantage of correlation, edge, and difference algorithm, when it detects any motion. At that time, to detect motion, it compares two images, which is from two cameras, to calculate disparity that contains distance information. By disparity, it can compute real distance and size of object information. We describe a motion detection algorithm which computes 3-D distance and object size in real time.

• Journal of Korean Association for Spatial Structures
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• v.2 no.1 s.3
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• pp.41-49
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• 2002

In this paper, a study of 2-step damage detection for space truss structures using the extended Kalman filter theory is presented. Space truss structures are composed of many members, so it is difficult to find damaged member from the whole system. Therefore, 2-step damage identification method is applied to detect the damaged members. First, kinetic energy change ratio is used to find damage region including damaged member and then detect damaged member using extended Kalman filtering algorithm in damage region. The effectiveness of proposed method is verified through the numerical examples.

• Textile Coloration and Finishing
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• v.26 no.1
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• pp.1-6
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• 2014

We have designed and synthesized the colorimetric chemosensor through the reactions of 1,2-anthraquinone and indol-3-carboxaldehyde. Due to its well conjugated D-${\pi}$-A system and the existence of NH-fragment in indole moiety, we expected that the chemosensor can detect target anions with NH-fragment in indole part of the structure. In this regard, UV-Vis absorption spectra were measured to investigate sensing properties of the probe toward different anions in DMSO. This chemosensor shows to detect fluoride anions with absorption change in intensity. These properties are mainly related to the deprotonation effect. ICT system in this molecule was also observed by the computational approach using Material Studio 4.3 package.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.3
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• pp.29-36
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• 2000

It is very import role to increase communication quality that fast detection of random sequence synchronization fail in synchronous stream cipher system using initial synchronization mode. Generally it sends additional information to detect random sequency synchronization fail. But we can't transmit additional informations to decide synchronization fail in a system using RMVD to correct channel error. In this paper we propose a method to detect synchronization fail in the receiver even though a system using RMVD has no margin to send additional information, For detecting random sequency synchronization fail we decipher receiver data analyze probability of transition rate for pre-determined period and decide synchronization fail using calculated transition rate probability. This proposed method is fast very reliable and robust in noisy channel and is easily implemented with hardware.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.158-164
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• 2011

Breast cancer is the most frequently appearing cancer in women, these days. To reduce mortality of breast cancer, periodic check-up is strongly recommended. X-ray mammography is one of powerful diagnostic imaging systems to detect 50~100 um micro-calcification which is the early sign of breast cancer. Although x-ray mammography has very high spatial resolution, it is not easy yet to distinguish cancerous tissue from normal tissues in mammograms and new tissue characterizing methods are required. Recently ultrasound elastography technique has been developed, which uses the phenomenon that cancerous tissue is harder than normal tissues. However its spatial resolution is not enough to detect breast cancer. In order to develop a new elastography system with high resolution we are developing x-ray elasticity imaging technique. It uses the small differences of tissue positions with and without external breast compression and requires an algorithm to detect tissue displacement. In this paper, computer simulation is done for preliminary study of x-ray elasticity imaging. First, 3D x-ray breast phantom for modeling woman's breast is created and its elastic model for FEM (finite element method) is generated. After then, FEM experiment is performed under the compression of the breast phantom. Using the obtained displacement data, 3D x-ray phantom is deformed and the final mammogram under the compression is generated. The simulation result shows the feasibility of x-ray elasticity imaging. We think that this preliminary study is helpful for developing and verifying a new algorithm of x-ray elasticity imaging.