Hua Fan

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A novel semi-fragile watermarking scheme for Image tamper localization and recovery is proposed. The Logistic map is used to encrypt the feature extracted from the original image, then the generated watermark is embedded into the middle-frequency DCT coefficients of each block after being ordered in zigzag manner based on invariance properties of DCT(More)
Different from traditional social networks, the location-based social networks allow people to share their locations according to location-tagged user-generated contents, such as checkins, trajectories, text, photos, etc. In location-based social networks, which are based on users' checkins, people could share his or her location according to checkin while(More)
A recent paper on benchmarking eventual consistency showed that when a constant workload is applied against Cassan-dra, the staleness of values returned by read operations exhibits interesting but unexplained variations when plotted against time. In this paper we reproduce this phenomenon and investigate in greater depth the low-level mechanisms that give(More)
Since John von Neumann suggested utilizing Logistic map as a random number generator in 1947, a great number of encryption schemes based on Logistic map and/or its variants have been proposed. This paper re-evaluates the security of an image cipher based on transformed logistic maps and proves that the image cipher can be deciphered efficiently under two(More)
NoSQL storage systems are used extensively by web applications and provide an attractive alternative to conventional databases when the need for scalability outweighs the need for transactions. Several of these systems, notably Amazon's Dynamo and its open-source derivatives, provide quorum-based replication and present the application developer with a(More)
In modern supply chain management systems, Radio Frequency IDentification (RFID) technology has become an indispensable sensor technology and massive RFID data sets are expected to become commonplace. More and more space and time are needed to store and process such huge amounts of RFID data, and there is an increasing realization that the existing(More)
Today's online applications depend on fast storage and retrieval of up-to-date data at web scale. To meet this growing demand, the designers of distributed storage systems have devised a rich variety of data replication protocols, offering different trade-offs between consistency, latency, and availability. Understanding the sweet spot, and testing whether(More)
Lack of capacity to cross the nucleus membrane seems to be one of the main reasons for the lower transfection efficiency of gene vectors observed in vivo study than in vitro. To solve this problem, a new non-viral gene vector was designed. First, a degradable polyethylenimine (PEI) derivate was synthesized by crosslinking low-molecular-weight (LMW) PEI with(More)