• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.10
• /
• pp.1774-1779
• /
• 2016

This paper proposes a portable cable fault detection system with automatic fault distinction and distance measurement using time-frequency correlation and reference signal elimination method and automatic fault classification algorithm in order to have more accurate fault determination and location detection than conventional time domain refelectometry (TDR) system despite increased signal attenuation due to the long distance to cable fault location. The performance of the developed system method was validated via an experiment in the test field constructed for the standardized performance test of power cable fault location equipments. The performance evaluation showed that accuracy of the developed system is less than 1.34%. Also, an error of automatic fault type and location by detection of phase and peak value through elimination of the reference signal and normalization of correlation coefficient and automatic fault classification algorithm not occurred.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.419-422
• /
• 2004

This paper was carried out desertification area change detection from 1980s to 2000s per unit decade using by multitemporal satellite images (Landsat MSS, TM, ETM+). This study aims to use Spectral Mixture Analysis (SMA) to identify and classify study area. Endmembers is selected bare soil, green vegetation (GV), water body using by Minimum Noise Fraction (MNF). Endmembers used to generate increase and decrease images respective from 1980s to 1990s and from 1990s to 2000s. From the analysis of multitemporal change detection for three periods, it was apparent that the area of bare soil increased significantly, with simultaneous decrease of GV and water body. The multitemporal fraction images can be effectively used for change detection. Though there is no field survey dataset, SMA is reliable result of change detection in desertification in China.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.896-902
• /
• 2000

Crack detection technique for concrete structures has been developed in this study,. The technique utilizes OTDR(Optical Time Domain Reflectometer) method that is widely used in the field of optical engineering. At present, some techniques, such as the naked eye inspection, inspection by crack gauge, ultra sonic detection and os on, are used for crack detection. However, these are not economical and are often time-consuming works. This method employs a common optical fiber as a means of crack detection. Th optical fiber is fully attached to concrete surface, and a crack on concrete could be detected to synchronize with the crack on optical fiber. The experimental verification was performed for concrete beams and the intial crack on the beam was detected under cracking force.

• Computers and Concrete
• /
• v.26 no.5
• /
• pp.411-420
• /
• 2020

Deep Convolution neural network (DCNN) has been widely used in the healthy maintenance of civil infrastructure. Using DCNN to improve crack detection performance has attracted many researchers' attention. In this paper, a light-weight spatial attention network module is proposed to strengthen the representation capability of ResNet and improve the crack detection performance. It utilizes attention mechanism to strengthen the interested objects in global receptive field of ResNet convolution layers. Global average spatial information over all channels are used to construct an attention scalar. The scalar is combined with adaptive weighted sigmoid function to activate the output of each channel's feature maps. Salient objects in feature maps are refined by the attention scalar. The proposed spatial attention module is stacked in ResNet50 to detect crack. Experiments results show that the proposed module can got significant performance improvement in crack detection.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1629-1632
• /
• 2008

Rapid, real-time detection of pathogenic microorganisms is an emerging and quickly evolving field of research, especially with regard to microorganisms that pose a major threat to public health. Herein, a new method that uses bioimpedance and solid culture medium for the real-time detection of microorganisms is introduced. We fabricated a new impedimetric biosensor by integrating solid media and two plane electrodes attached on two facing sides of an acryl well. During bioelectrical impedance analysis, the solid medium showed the characteristics of a homogenous conductive material. In a real-time impedance measurement, our solid-medium biosensor could monitor bacterial growth in situ with a detection time of ${\sim}4$ hrs. Our data indicate that the solid-medium biosensor is useful for detecting airborne microorganisms, thereby providing a new analytical tool for impedance microbiology.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.171-171
• /
• 2000

We have developed m innovative surface inspection system for automated quality control for steel products in POSCO. We had ever installed the various kinds of surface inspection systems, such as a linear CCD and a laser typed surface inspection systems at cold rolled strips production lines. But, these systems cannot fulfill the sufficient detection and classification rate, and real time processing performance. In order to increase detection and classification rate, we have used the Dark, Bright and Transition Field illumination and area type CCD camera, and fur the real time image processing, parallel computing has been used. In this paper, we introduced the automatic surface inspection system and real time image processing technique using the Object Detection, Defect Detection, Classification algorithms and its performance obtained at the production line.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.11
• /
• pp.5592-5609
• /
• 2017

JPEG steganography detection is an active research topic in the field of information hiding due to the wide use of JPEG image in social network, image-sharing websites, and Internet communication, etc. In this paper, a new steganalysis method for content-adaptive JPEG steganography is proposed by integrating the evolutionary feature selection and classifier ensemble selection. First, the whole framework of the proposed steganalysis method is presented and then the characteristic of the proposed method is analyzed. Second, the feature selection method based on genetic algorithm is given and the implement process is described in detail. Third, the method of classifier ensemble selection is proposed based on Pareto evolutionary optimization. The experimental results indicate the proposed steganalysis method can achieve a competitive detection performance by compared with the state-of-the-art steganalysis methods when used for the detection of the latest content-adaptive JPEG steganography algorithms.

• Proceedings of the KIEE Conference
• /
• 1997.07b
• /
• pp.714-716
• /
• 1997

In order to prevent the belt from being damaged by metal pieces, we developed multicoil-type metal detection system. This detects the presence of belt clips and position of metal pieces in ores being transported on conveyor belt. In this research, our coil sensor of multicoil-type metal detection system is divided into two parts, exciting part (transmitter coil) and sensing part composed of two receiver coils. Each receiver coil has several coils in the direction of belt width. Multicoil-type metal detection system is operated by supplying a transmitter coil with electric power resources to generate magnetic field, and then the change of magnetic flux resulted from a metal piece on the conveyor be a is induced into sensing coils. We can prevent detector from failing to catch metal pieces due to high threshold level produced by steel belt clips and male the sensitivity of belt-width direction uniform by using multicoil-type metal detection system. Besides, this developed system can recognize precise position and size of metal piece. The experiments shows that our multicoil-type metal detection system has better performances than the conventional metal piece detector.

• Nuclear Engineering and Technology
• /
• v.52 no.10
• /
• pp.2151-2161
• /
• 2020

The study presents a review of research advancements in the field of gamma radiation detection systems for emergency radiation monitoring, particularly two major sub-systems namely (i) the radiation detector and (ii) the detection platform - air-borne and ground-based. The dynamics and functional characteristics of modern radiation detector active materials are summarized and discussed. The capabilities of both ground-based and aerial vehicle platforms employed in gamma radiation monitoring are deliberated in depth.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.55 no.5
• /
• pp.179-184
• /
• 2006

In a power system, an out-of-step condition causes a variety of risk such as serious damage to system elements, tripping of loads and generators, mal-operation of relays, etc. Therefore, it is very important to detect the out-of- step condition and take a proper measure. This paper presents a study on implementation of out-of-step detection algorithm using VHDL(Very high speed Hardware Description Language). The structure of out-of-step detection algorithm is analyzed for development of out-of-step detection relay on the FPGA(Field Programmable Gate Array). The out-of-step algorithm is separated to 4 parts: DFT IP, complex power calculation IP, out-of-step detection IP, control unit. Each parts are developed and simulated by using VHDL.