• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.107-112
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• 2014

In this paper, we analysed a performance signal to noise ratio about pulse, integration coherent, and integration non coherent system in radar system. It compared existing with proposal method in order to estimation two target direction of arrival. Generally, radar system radiate pulse wave in order to decreasing distortion of return wave and transmission wave. We analysed the performance integration coherent and integration non coherent. Integration coherent is processing system before doing envelop detection, and integration non coherent is processing system after doing envelop detection. Through simulation, we analysed a performance signal to noise ratio to estimation two target range detection and estimated target direction of arrival. We showed that integration coherent system is the most good performance.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.396-409
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• 2012

With the proliferation of diverse wireless devices, there is an increasing concern about the security of location information which can be spoofed or disrupted by adversaries. This paper investigates the characterization and detection of location spoofing attacks, specifically those which are attempting to falsify (degrade) the position estimate through signal strength based attacks. Since the physical-layer approach identifies and assesses the security risk of position information based solely on using received signal strength (RSS), it is applicable to nearly any practical wireless network. In this paper, we characterize the impact of signal strength and beamforming attacks on range estimates and the resulting position estimate. It is shown that such attacks can be characterized by a scaling factor that biases the individual range estimators either uniformly or selectively. We then identify the more severe types of attacks, and develop an attack detection approach which does not rely on a priori knowledge (either statistical or environmental). The resulting approach, which exploits the dissimilar behavior of two RSS-based estimators when under attack, is shown to be effective at detecting both types of attacks with the detection rate increasing with the severity of the induced location error.

• Journal of Sensor Science and Technology
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• v.20 no.6
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• pp.420-427
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• 2011

The population of elderly people increases rapidly as our society moves towards the aged one. Healthcare for the elderly becomes an important issue and falling down is one of the critical problems although not well recognized. In this study, a fall detection system was developed using a 3-axis accelerometer. Analyzing fall patterns, we took into account the degree of impact, posture angle, the repetitions of similar movements and the activities after a potential fall and proposed an algorithm of fall detection. Information of the fall sensor was sent to a remote healthcare server through the wireless networks of Zigbee and WLAN. Our system was designed to monitor multiples users. 12 persons participated in experiment and each one performed 24 different movements. Our proposed algorithm was compared with other reported ones. Our method produced the excellent results having a sensitivity of 96.4 % and a specificity of 100 % whereas other methods had a sensitivity range between 87.5 % and 94.8 % and a specificity range between 63.5 % and 83.3 %.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.151-160
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• 2007

We report the label-free biomolecules detection based on nanomechanical micro cantilevers operated in dynamic mode for detection of two marker proteins (myoglobin and creatin kinase-MB (CK-MB)) of acute myocardical infarctions. When the specific binding between the antigen and its antibody occurred on the fuctionalized microcantilever surface, mechanical response (i.e. resonant frequency) of microcantilevers was changed in lower frequency range. We performed the label-free biomolecules detection of myoglobin and CK-MB antigen in the low concentration (clinical threshold concentration range) as much as 1 ng/ml from measuring the dynamic response change of micro cantilevers caused by the intermolecular force. Moreover, we estimate the surface stress on the dynamic microcantilevers generated by specific antibody-antigen binding. It is suggested that our dynamic microcantilevers may enable one to use the sensitive label-free biomolecules detection for application to the disease diagnosis system based on mechanical immuno-sensor.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.2
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• pp.97-101
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• 2022

In this paper, we propose a method of measuring Fine dust in images using K-means and Sobel-mask based edge detection techniques using CCTV. The proposed algorithm collects images using a CCTV camera and designates an image range through a region of interest. When clustering is completed by applying the K-means algorithm, outline is detected through Sobel-mask, edge strength is measured, and the concentration of fine dust is determined based on the measured data. The proposed method extracts the contour of the mountain range using the characteristics of Sobel-mask, which has an advantage in diagonal measurement, and shows the difference in detection according to the concentration of fine dust as an experimental result.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.6
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• pp.638-644
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• 2021

Infrared guided weapons act as threats that greatly degrade the survivability of combat aircraft. Infrared weapons detect and track the target aircraft by sensing the infrared signature radiated from the aircraft fuselage. Therefore, in this study, we analyzed the infrared signature and susceptibility of supersonic aircraft according to omni-directional detection angle. Through the numerical analysis, we derived the surface temperature distribution of fuselage and omni-directional infrared signature. Then, we calculated the detection range according to detection angle in consideration of IR sensor's parameters. Using in-house code, the lethal range was calculated by considering the relative velocity between aircraft and IR missile. As a result, the elevational susceptibility is larger than the azimuthal susceptibility, and it means that the aircraft can be attacked in wider area at the elevational situation.

• Progress in Superconductivity
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• v.14 no.2
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• pp.96-98
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• 2012

Bias current dependence of a superconducting strip photon detector is studied in the wavelength range of 405 to 1310 nm. The detector is made of an $MgB_2$ meander pattern with the line width of 135 nm and thickness of 10 nm. At 1310 nm, the detection efficiency exponentially decreases as the bias current decreases. While at 405 nm, the detection efficiency almost saturates in the high bias current region. These features suggest that the intrinsic detection efficiency of the $MgB_2$ detector is high at 405 nm.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1297-1304
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• 2008

This paper proposes a machine learning approach for language-independent sentence boundary detection. The proposed method requires no heuristic rules and language-specific features, such as part-of-speech information, a list of abbreviations or proper names. With only the language-independent features, we perform experiments on not only an inflectional language but also an agglutinative language, having fairly different characteristics (in this paper, English and Korean, respectively). In addition, we obtain good performances in both languages. We have also experimented with the methods under a wide range of experimental conditions, especially for the selection of useful features.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1244-1248
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• 2005

In this paper, we propose fuzzy c-means (FCM) to solve recognition errors in invariant range image, multi-pose face recognition. Scale, center and pose error problems were solved using geometric transformation. Range image face data was digitized into range image data by using the laser range finder that does not depend on the ambient light source. Then, the digitized range image face data is used as a model to generate multi-pose data. Each pose data size was reduced by linear reduction into the database. The reduced range image face data was transformed to the gradient face model for facial feature image extraction and also for matching using the fuzzy membership adjusted by fuzzy c-means. The proposed method was tested using facial range images from 40 people with normal facial expressions. The output of the detection and recognition system has to be accurate to about 93 percent. Simultaneously, the system must be robust enough to overcome typical image-acquisition problems such as noise, vertical rotated face and range resolution.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.333-336
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• 2000

In this paper, a profile management system consisting of global and local range finders is presented for the automat ion of material pile handling. A global range finder detects range data of the front part of the piles of material and a profile map is obtained from a 3D profile detection algorithm. A local range finder attached on the side of the arm of the reclaimer detects range data with the handling function dynamically, and a local profile patch is acquired from the range data A yard profile map manager constructs a map by using the 3D profile of the global range finder and revises the map by replacing it with the local profile patch obtained Iron the local range finder. The developed vision system was applied to a simulator and the results of test show that it is appropriate to use for automating the material handling.