• KIISE Transactions on Computing Practices
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• v.21 no.1
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• pp.58-63
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• 2015

In this work, we present a novel fountain code-based hybrid P2P storage system that combines cloud storage with P2P storage. The proposed hybrid storage system minimizes data transmission time while guaranteeing high data retrieval and data privacy. In order to guarantee data privacy and storage efficiency, the user transmits encoded data after performing fountain code-based encoding. Also, the proposed algorithm guarantees the user's data retrieval by storing the data while considering each peer's survival probability. The simulation results show that the proposed algorithm enables fast completion of the upload transmission while satisfying the required data retrieval and supporting the privacy of user data under the system parameters.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.133-139
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• 2017

To address the problems caused by such high installation and maintenance cost in the conventional server-based cloud systems, researches on P2P cloud storages have been conducted recently. In this paper, we propose a hierachical overlay structure that can improve the playback quality in P2P cloud storage systems for video transmission. In this structure, after we make groups by clustering the participating peers based on their similarities, we construct subgroups by geographically dividing the peers belonging to a specific group considering the physical proximities among them. Therefore, when a request for video playback is issued, we can minimize the transmission delay by selecting the source peers depending on their locality. By simulations, we show that our proposed hierarchical overlay structure considering the peers' locality outperforms the structure where source peers are selected randomly.

• Smart Media Journal
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• v.12 no.11
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• pp.145-153
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• 2023

In a P2P-based distributed storage system where peers frequently join and leave, it is essential to guarantee not only data availability but also playback quality comparable to that provided by local storage devices when playing back video files with real-time constraints. In addition, cloud storage services based on distributed storage systems provide each user with the functionality to share their files with other users, so when multiple users request playback of the same video file at the same time, all playback should be supported seamlessly in real time. Therefore, in this paper, we propose a scheme that process multiple simultaneous playback requests for each video file in real time as well as data availability in a P2P-based distributed storage system that supports file sharing. This scheme can support real-time simultaneous playback and efficiently use storage space by adjusting the amount of redundant data encoded through erasure coding according to the number of concurrent playback requests for each video file.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.666-672
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• 1995

This study was carried out to characterize thermolabile pectinesterase (TLPE) and thermostable pectinesterase (TSPE) separated from crude PE of Valencia orange in order to investigate the preventive measures of cloudy juice clarification. The TLPE was observed to be mixture of several isoenzymes with the same molecular weight of 36 KD (37.5 KD) but different isoelectric point of pH 8.4, 8.7, 8.9, 9.8 and ${\geq}10$ which were unstable at $70^{\circ}C$, and the TSPE also was found to be mixture of two or three isoenzymes with the same molecular weight of 53 KD (50 KD) but different isoelectric point of pH 8.7, 9.2 and ${\geq}10$ which had slightly different stability from one another at $70^{\circ}C$. The TLPE and the TSPE had the optimum reaction pH of 7.0 and $7.0{\sim}8.5,\;appK_{M}$ of 1.1 and 1.7 mg/ml, appVmax of 0.53 and $1.01\;{\mu}mol/min/{\mu}g$, and the turnover number of 19.000 and 54,000 mol/mol/min toward Kodak pectin, respectively. The TSPE had higher storage stabiblity and cloud loss effect on orange juice than the TLPE. Above all, the crude PE was most effective on orange juice cloud loss among the PEs used.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.295-311
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• 2023

Cloud computing has evolved significantly, intending to provide users with fast, dependable, and low-cost services. With its development, malicious users have become increasingly capable of attacking both its internal and external security. To ensure the security of cloud services, encryption, authorization, firewalls, and intrusion detection systems have been employed. However, these single monitoring agents, are complex, time-consuming, and they do not detect ransomware and zero-day vulnerabilities on their own. An innovative Record and Replay-based hybrid Honeynet (R2NET) system has been developed to address this issue. Combining honeynet with Record and Replay (RR) technology, the system allows fine-grained analysis by delaying time-consuming analysis to the replay step. In addition, a machine learning algorithm is utilized to cluster the logs of attackers and store them in a database. So, the accessing time for analyzing the attack may be reduced which in turn increases the efficiency of the proposed framework. The R2NET framework is compared with existing methods such as EEHH net, HoneyDoc, Honeynet system, and AHDS. The proposed system achieves 7.60%, 9.78%%, 18.47%, and 31.52% more accuracy than EEHH net, HoneyDoc, Honeynet system, and AHDS methods.