• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.1067-1078
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• 2020

With the development of internet technology, a lot of content is produced, and the demand for it is increasing. Accordingly, the number of contents in circulation is increasing, while the number of distributing illegal copies that infringe on copyright is also increasing. The Korea Copyright Protection Agency operates a illegal content obstruction program based on substring matching, and it is difficult to accurately search because a large number of noises are inserted to bypass this. Recently, researches using natural language processing and AI deep learning technologies to remove noise and various blockchain technologies for copyright protection are being studied, but there are limitations. In this paper, noise is removed from data collected online, and keyword-based illegal copies are searched. In addition, the same heavy uploader is estimated through profiling analysis for heavy uploaders. In the future, it is expected that copyright damage will be minimized if the illegal copy search technology and blocking and response technology are combined based on the results of profiling analysis for heavy uploaders.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.147-147
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• 1993

All types of dynamic excitation, periodical, pulse or transient in vertical, horizontal or all three directions can be effectively reduced by vibration isolation systems. Typical elements for vibration isolation control are spring units consisting of a group of helical compression springs. In all cases of shock, transient or random excitation energy absorbing dampers have to be added to the spring units in order to reduce system response in the frequency range near the natural frequency of the isolation system. The same isolation system of spring units and viscos-dampers has been used since 1979 for passive protection of buildings and structures has been proved to by very advantageous for vibration and structure borne noise control. Not only because of high vertical flexibility of the spring units, compared for example with typical rubber or neoprene mounts out also because of the horizontal of flexibility, which can be adapted by modifying the spring dimensions to nearly every requirement. It is just normal to use the same basic elements for passive isolation as for active isolation.

• Journal of Environmental Health Sciences
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• v.36 no.5
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• pp.411-417
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• 2010

The Seoul metropolitan government has installed soundproofing walls in road tunnels to improve the tunnel environment for pedestrians. To evaluate the efficiency of these soundproofing walls, we measured noise levels and concentrations of $PM_{2.5}$ and ultrafine particles (UFP) in tunnels with or without these walls. Although noise and UFP levels were significantly lower in the tunnels with soundproofing walls, $PM_{2.5}$ levels were significantly higher: but were significantly lowered by use of a ventilation system. When $PM_{2.5}$ and noise levels were simultaneously measured in a tunnel with soundproofing wall, noise level was significantly reduced but $PM_{2.5}$ level was significantly higher. It is concluded that the soundproofing wall can protect pedestrians from noise, but not PM. Installation of a ventilation system is recommended for protection of pedestrians in tunnels with soundproofing walls.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.99-108
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• 2015

The embedded microcontroller which is operated by the logic gates synchronized on the clock pulse, is gradually used as main controller of mission-critical systems. Severe electrical situations such as high voltage/frequency surge may cause malfunctioning of the clock source. The tolerant system operation is required against the various external electric noise and means the robust design technique is becoming more important issue in system clock failure problems. In this paper, we propose on-chip backup clock change architecture for the automatic clock failure detection. For the this, we adopt the edge detector, noise canceller logic and glitch-free clock changer circuit. The implemented edge detector unit detects the abnormal low-frequency of the clock source and the delay chain circuit of the clock pulse by the noise canceller can cancel out the glitch clock. The externally invalid clock source by detecting the emergency status will be switched to back-up clock source by glitch-free clock changer circuit. The proposed circuits are evaluated by Verilog simulation and the fabricated IC is validated by using test equipment electrical field radiation noise

• Journal of Radiation Protection and Research
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• v.38 no.1
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• pp.29-36
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• 2013

The aim of this study was to determine the correlation between exposure index (EI) and dose factors related to radiation dose optimization in digital radiography (DR) system. Two phantoms with built-in regional test object for quantitative assessment of images were used to produce image signals that acquired in chest radiography background. EI and entrane surface dose (ESD) increased proportionally with rise of radiation dose (kVp, mAs) in both DR and CR systems. Especially, DR detector was effective to form good contrast and hence, reached easily to improvement of image quality with minimal dose changes. It made operators possible to expect the accuracy of EI values deeply related to absorbed dose of the detector. The evaluation of images was obtained specially employed calculation of noise to signal ratio (NSR) and contrast to noise ratio (CNR). These measurements were performed for how exposure factors affect image quality. NSR was inversely proportional to kVp and mAs and low NSR represented high signal detection efficiency. Consequently, EI values was the measure of the amount of exposure received by the image receptor and it was proportional to exposure factors. Therefore the EI in a recommended range from manufacturer can offer optimal image quality. Also, continuous monitoring of EI values in the digital radiography can reduce the unnecessary patient dose and help the quality control of the system.

• Explosives and Blasting
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• v.11 no.2
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• pp.60-68
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• 1993

The noise and vibration generated by the subway rolling stocks operated along the Seoul Subway Line No.1, 2, 3, and 4 lead to a controversy of pollution problem especially in residential areas. However, there is no data or guide to define the damage or provide adequate protection against such pollutions. The field measurements were made to characterize the noise attenuation due to distance, noise level distribution around the subway track of the aboveground and underground parts of each Line. The assessment criteria and methods are considered in addition to the practical available noise control methods. The noise level measured at Line No. 1 and 3 are less than 60 dB(A) with no pollution problem. Only a part of the aboveground section of Line No.2 and 4 indicates severe noise pollution. The effective boundary of these areas exposed to 70dB (A) noise are within 50m from the track centerline of No.2 line and 25m of No.4 line. The residents file a strong complaints whenever the noise level exceeds the 80dB (A) , and an occasional complaints between 70 to 80 dB(A). The distribution of high level noise of 80 dB(A) occurs within 25m from the track centerline of the overbridge, 12.5m of the short steel bridge, and about loom of the long steel bridge such as Dangsan Bridge. The intermediate noise level of 70 to 80 dB(A) is recorded within 50m from the overbridge, U-type retaining structure, and short steel structure, and 280m from the long steel bridge. The results presented in this paper can be used to understand the characteristics of the noise pollution along the Seoul Subway now In operation, and used as a guide to improve the existing noise pollution problems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3826-3851
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• 2016

With traditional data storage solutions becoming too expensive and cumbersome to support Big Data processing, enterprises are now starting to outsource their data requirements to third parties, such as cloud service providers. However, this outsourced initiative introduces a number of security and privacy concerns. In this paper, homomorphic encryption is suggested as a mechanism to protect the confidentiality and privacy of outsourced data, while at the same time allowing third parties to perform computation on encrypted data. This paper also discusses the challenges of Big Data processing protection and highlights its differences from traditional data protection. Existing works on homomorphic encryption are technically reviewed and compared in terms of their encryption scheme, homomorphism classification, algorithm design, noise management, and security assumption. Finally, this paper discusses the current implementation, challenges, and future direction towards a practical homomorphic encryption scheme for securing outsourced Big Data computation.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.223-226
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• 2007

This paper first outlines the technology used in Power Line Communications(PLC) systems, and the political support being offered to the technology, from the point of view of its effect on electromagnetic compatibility (EMC). The radio spectrum needs protection from other interferers, and there is a regime in place to provide this interference avoidance/mitigation. Nevertheless, PLC has several features that mean that it is capable of creating such interference. These features are discussed, and some published field trial results are reviewed. Difficulties in achieving compatibility between the requirements for radio protection and the requirements for operation of the PLC system mean that there is no consensus as yet as to how PLC system components can be made compliant with EMC requirements. It is concluded that there is little prospect of an accommodation between the competing demands, so that if PLC is to become widespread it will be at the expense of the radio environment.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.124-127
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• 2003

In this research, a watermarking scheme for multimedia content service under the mobile envrionment is proposed. The proposed watermarking scheme that adds robustness to the errors occured in the mobile envrionment existing the pathloss, fading, interference and noise was designed. In case of the multimedia content service under the mobile envrionment, Possible methods for important matters to be considered for the copyright protection, construction of the watermark and position of insertion and detection are also proposed. It is observed that a watermark is composed of information of the mobile user Insertion and detection of the watermark is implemented with CDMA technique in the frequency region.

• 한국터널공학회:학술대회논문집
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• 2005.04a
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• pp.63-74
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• 2005

The environmental influence in tunnel construction is the drying of the ground water, the drop of the ground water level, and noise and vibration by tunnel excavation. The environmental influence can cause the change of natural ecosystem and the source of popular complaints. In case of popular complaints, the tunnel construction can be stopped or the construction period can be extended. Also, the financial loss may be reached to hundreds of billions won. The technology development to minimize the environmental influence in the tunnel construction is very important in order to control popular complaints and to preserve ecosystem. It should be required the investigation, the evaluation, and the assessment of environmental impact to reduce environmental influence in the tunnel construction. The objective of this research is to review the environmental impact assessment in Korea and to introduce the environmental protection technology which minimizes the environmental influence generated in the tunnel construction.