A Fuzzy Algorithm of Peer Selection for P2P Streaming Media System Based on Gossip Transmission Protocol

Xunli Fan,Weiwei Zhang,Lin Guan 보안공학연구지원센터 2009 International Journal of Multimedia and Ubiquitous Vol.4 No.1

The traditional Gossip protocol selects the neighbor nodes randomly. It does not consider the factors, such as the capacities of network transmission and node storage, which affect the network performance. It further causes the drawback of successful search ratio relatively lower, and also network transmission payloads have the characteristics of randomness. In this paper, to overcome those drawbacks of traditional Gossip protocol, a neighbor node selection algorithm has been studied, and various factors that may affect the neighbor node selection have been analyzed in P2P networks. A new neighbor node selection policy has been proposed, which is a reliable Gossip message transmission Protocol based on fuzzy theory. Empirical simulation experiments with various data analysis have demonstrated the improvement of efficiency of the proposed strategy on node selection and correctness of the proposed algorithm in P2P networks.

Optimized Identification Method for Digital Music Pieces in BitTorrent

Xun Jin,Jongweon Kim 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.1

In this paper, we propose a methodology for identification of MP3 audio pieces downloaded by BitTorrent client program using cross-correlation of 12 chroma features extracted from audio signal. To prevent illegal distribution of copyrighted audio files from spreading over the internet, the file pieces split by torrent file must be detected as accurately as possible. In order to improve the probability of successfully identifying the audio pieces, we use Peak In Piece Position (PIPP) method which means the maximum peak appeared in a range corresponding to piece position and length is selected to reduce the probability of misidentification. The experimental results show probabilities of successfully identification of the pieces with different piece properties, comparisons between the proposed algorithms and conventional algorithm in terms of precisions and robustness of the proposed algorithms.

Effects of coolant temperature on particulate deposition and cooling efficiency of EGR coolers

Xun Zhang,Wei Tian,Jinhui Li,Zhiqiang Han,Xueshun Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

Porous fouling layers formed by particulate deposition in the EGR cooler tubes degrade the cooling efficiency of the EGR coolers. This research has investigated the changes of the particulate concentration under varied coolant temperature conditions and the effects of the coolant temperature on the cooling efficiency of the cooler tubes by measuring the particulate concentration and size distribution at the cooler inlet and outlet. The experiment results indicate that for the particulates of different sizes, the thermophoretic force acting on them and the regeneration vary under the same experiment conditions, presenting distinctive effects on the particulate concentration distribution in the exhaust gas and causing concentrations of nuclear particulates and aggregated particulates to change, respectively. The mass of fouling layers inside the cooler tubes increases as the coolant temperature decreases. Decreasing the coolant temperature not only increases the quantity of fouling particulates but also forms more particulates of big sizes, causing cooling efficiency of the cooler tube per unit length to decrease with the decrease of coolant temperature and the increase of the tube length.

Construct a Binary Three-Layer Perceptron with Less Memory Size

Xun Liang,Shao Wei Xia,Zhong Ren Liu,Hui Su 대한전자공학회 1994 ICONIP : International Conference On Neural Inform Vol.1 No.3

Learning New Knowledge without influencing the Old in Expert Systems Based on Neural Network

Xun Liang,Ji Hong Du,Shawei Xia,Li Li 대한전자공학회 1994 ICONIP : International Conference On Neural Inform Vol.3 No.2

Audio Fragment Identification System

Xun Jin,Jongweon Kim 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.12

Audio identification technologies are becoming of increasing interest for copyright protection and digital forensic. In this paper, we propose an audio fragment identification system for efficient audio identifying applications in practice. To identify an audio file fragment, we have to decode it according to its format. Thus, we precede format classification of audio fragment using Support Vector Machine in advance. After identify the format, fragment recovery is implemented by adding a maximum similar frame header in front of the fragment. Then we extract a chroma feature from the decoded audio data to achieve audio identification. The experimental results show the evaluations of the format classification, fragment recovery and audio identification.

Numerical Simulation on Characteristics of Debris Clouds Produced by Conical Projectiles Hypervelocity Impact on Thin Plates

Xun Liu,Fangfang Gai,Su Cheng 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6

With the unceasing development of space activity, the total number of space debris is ever increasing, which greatly threatens orbiting space vehicles. To research the characteristics of debris clouds which are produced by conical projectiles hypervelocity impact on thin plates, SPH (smoothed particle hydrodynamics) methods in AUTODYN is used. Characteristics of debris cloud produced by conical projectiles with different ratio between length and diameter hypervelocity impact on thin plates are investigated with the same mass and velocity by numerical simulation. Effects of the ratio between length and diameter of the projectiles affecting on the form of debris cloud, axial location of debris clouds, radial extension of debris cloud and tip particle velocity of debris cloud are obtained. It is shown that the degree of fragmentation of the projectiles and debris cloud diffusion is changed with the velocity of the projectiles, the ratio between length and diameter and the impacting direction. The increasing ratio between length and diameter of projectiles can reduce the damage of thin plates but rise the damage of the wall of spacecraft by the debris clouds impact on with the same mass and velocity.

Provably Secure Aggregate Signcryption Scheme

Xun-Yi Ren,Zheng-Hua Qi,Yang Geng 한국전자통신연구원 2012 ETRI Journal Vol.34 No.3

An aggregate signature scheme is a digital signature scheme that allows aggregation of n distinct signatures by n distinct users on n distinct messages. In this paper, we present an aggregate signcryption scheme (ASC) that is useful for reducing the size of certification chains (by aggregating all signatures in the chain) and for reducing message size in secure routing protocols. The new ASC scheme combines identity-based encryption and the aggregation of signatures in a practical way that can simultaneously satisfy the security requirements for confidentiality and authentication. We formally prove the security of the new scheme in a random oracle model with respect to security properties IND-CCA2, AUTH-CMA2,and EUF-CMA.

Robust Digital Watermarking for High-definition Video using Steerable Pyramid Transform, Two Dimensional Fast Fourier Transform and Ensemble Position-based Error Correcting

( Xun Jin ),( Jongweon Kim ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7

In this paper, we propose a robust blind watermarking scheme for high-definition video. In the embedding process, luminance component of each frame is transformed by 2-dimensional fast Fourier transform (2D FFT). A secret key is used to generate a matrix of random numbers for the security of watermark information. The matrix is transformed by inverse steerable pyramid transform (SPT). We embed the watermark into the low and mid-frequency of 2D FFT coefficients with the transformed matrix. In the extraction process, the 2D FFT coefficients of each frame and the transformed matrix are transformed by SPT respectively, to produce two oriented sub-bands. We extract the watermark from each frame by cross-correlating two oriented sub-bands. If a video is degraded by some attacks, the watermarks of frames contain some errors. Thus, we use an ensemble position-based error correcting algorithm to estimate the errors and correct them. The experimental results show that the proposed watermarking algorithm is imperceptible and moreover is robust against various attacks. After embedding 64 bits of watermark into each frame, the average peak signal-to-noise ratio between original frames and embedded frames is 45.7 dB.

Numerical investigation of the effect of surface roughness on the flow coefficient of an eccentric butterfly valve

Xun Sun,김현수,양승덕,김철규,윤준용 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

Butterfly valves are used widely as flow controllers in many industrial applications. In order to design and select an appropriate valvefor a particular application, it is important to predict correctly its flow coefficient. The flow coefficient of a valve can be affected by anumber of factors. This study presents a numerical investigation of the effect of friction on the flow coefficient of a triple eccentric butterflyvalve with various valve opening degrees. Since the Reynolds number and cavitation can affect the flow coefficient under certainconditions, these effects are discussed and analyzed based on previously reported experimental data before studying the effects of friction. Under the test conditions recommended in IEC 60534-2-3, it is found that the effects of the Reynolds number and cavitation are quitesmall and can be ignored. The flow coefficients obtained from numerical simulations that take into account friction are found to be ingood agreement with the experimentally determined ones. The differences in the flow coefficients obtained from numerical simulationsthat consider friction and those that ignore it are discussed. There is a maximum difference of 17 % for a fully open valve. The resultsshow that increases in the roughness height significantly increase the frictional pressure drop. The effect of the roughness height on thefrictional pressure drop and total pressure drop can be fitted well using fitting functions for fixed opening degree. It is found that the effectof the roughness can cause the determined flow coefficient to be different from the actual value. Thus, the measured flow coefficientsand pressure drops for such valves can be determined with accuracy through experimental techniques and numerical simulationsthat account for the effect of roughness.