Trajectories representing the motion of moving objects are typically obtained via location sampling, e.g. using GPS or road-side sensors, at discrete time-instants. In-between consecutive samples, nothing is known abo...
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ISBN:
(纸本)9781450305280
Trajectories representing the motion of moving objects are typically obtained via location sampling, e.g. using GPS or road-side sensors, at discrete time-instants. In-between consecutive samples, nothing is known about the whereabouts of a given moving object. Various models have been proposed (e.g., sheared cylinders;spacetime prisms) to represent the uncertainty of the moving objects both in unconstrained Euclidian space, as well as road networks. In this paper, we focus on representing the uncertainty of the objects moving along road networks as time-dependent probability distribution functions, assuming availability of a maximal speed on each road segment. For these settings, we introduce a novel indexing mechanism - UTH (Uncertain Trajectories Hierarchy), based upon which efficient algorithms for processing spatio-temporal range queries are proposed. We also present experimental results that demonstrate the benefits of our proposed methodologies.
To detect image copy-paste tampering, an improved blind identification was proposed in this study. Firstly, according to gray-level and gray-structure, every couple of doubtful blocks can be located. Secondly, for eac...
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ISBN:
(纸本)9781601321916
To detect image copy-paste tampering, an improved blind identification was proposed in this study. Firstly, according to gray-level and gray-structure, every couple of doubtful blocks can be located. Secondly, for each located couple of doubtful blocks, use logarithm polar coordinate transformation to translate the rotation and scaling in Cartesian coordinate system into translation in logarithm polar coordinate system;and use phase correlation method to obtain rotation angle, scaling size and position offset;and then, the tampered regions would be located roughly. Finally, use geometry method to accurately calculate the rotation angle, scaling size and position offset between the copy-paste regions, and according to these values, the tampered region can be located accurately. Experimental results showed that our algorithm can detect the copy-paste tampering, even with rotation and scaling transformation, and it can resist some post-processing, such as blurring, adding noise, and so on.
In many areas, a lot of data have been modeled by graphs which are subject to uncertainties, such as molecular compounds and protein interaction networks. While many real applications, for example, collaborative filte...
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In many areas, a lot of data have been modeled by graphs which are subject to uncertainties, such as molecular compounds and protein interaction networks. While many real applications, for example, collaborative filtering, fraud detection, and link prediction in social networks etc, rely on efficiently answering k-nearest neighbor queries (kNN), which is the problem of computing the most "similar" k nodes to a given query node. To solve the problem, in this paper a novel method based on measurement of SimRank is proposed. However, because graphs evolve over time and are uncertainly, the computing cost can be very high in practice to solve the problem using the existing algorithms of SimRank. So the paper presents an optimization algorithm. Introducing path threshold, which is suitable in both determined graph and uncertain graph, the algorithm merely considers the local neighborhood of a given query node instead of whole graph to prune the search space. To further improving efficiency, the algorithm adopts sample technology in uncertain graph. At the same time, theory and experiments interpret and verify that the optimization algorithm is efficient and effective.
Access control is essential to computer security, especially in an open, distributed, networked communication environment. Modern access control model such as UCON aims at accommodating general requirements. Tradition...
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Access control is essential to computer security, especially in an open, distributed, networked communication environment. Modern access control model such as UCON aims at accommodating general requirements. Traditional one such as BLP focuses on specific properties, e.g. confidentiality. Both of these two realms have their limitations. Taking UCON and BLP as case study, this paper explores mutual support of modern and traditional access control models. It investigates BLP's adaptable characteristic in the UCON perspective. First, it constructs properties in the UCON language to manifest the BLP adaptability, which shows that the BLP adaptability can be ensured to function correctly by the UCON framework. Further, it proposes a formal specification for the BLP adaptability under the UCON framework with the Temporal Logic of Actions, which demonstrates that the BLP adaptability is in good consistency with the UCON model. The significance of the paper is twofold. On the one hand, it exhibits that adaptable quality of the traditional BLP model may be ensured theoretically by the philosophy of modern access control. On the other hand, it enriches the real sense of modern access control models by strengthening the power of traditional access control models.
Max Restricted Path Consistency (maxRPC) is a promising domain filtering consistency for binary constraints. In existing algorithms, the process of searching for PC-witnesses requires most constraint checks. And the c...
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Topological relations between spatial objects have played important roles in spatial representing and reasoning. Various models for expressing topological relations have been put forward. The Region Connection Calculu...
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Wireless communication, signal broadcasting, strictly limited resources in tags make RFID systems being confronted with many security attacks and privacy disclosure threats. In this paper, an efficient lightweight RFI...
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Wireless communication, signal broadcasting, strictly limited resources in tags make RFID systems being confronted with many security attacks and privacy disclosure threats. In this paper, an efficient lightweight RFID mutual authentication protocol is proposed, this protocol only requires O(1) work to identify and authenticate a tag in the backend server and is particularly suitable for the low-cost RFID systems because only one-way hash function, XOR operation and concatenation operation are needed in tags. The security and performance of this protocol are analyzed as well by comparing with the related RFID authentication protocols.
Domain terms play a crucial role in many research areas, which has led to a rise in demand for automatic domain terms extraction. In this paper, we present a two-level evaluation approach based on term hood and unit h...
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作者：
LI YONGXU LUCollege of Mathematics
Key Laboratory of Symbolic computation and Knowledge Engineering of Ministry of EducationJilin UniversityChangchun130012
In this paper,we study the persistence of lower dimensional tori for random Hamiltonian systems,which shows that majority of the unperturbed tori persist as Cantor fragments of lower dimensional ones under small *** t...
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In this paper,we study the persistence of lower dimensional tori for random Hamiltonian systems,which shows that majority of the unperturbed tori persist as Cantor fragments of lower dimensional ones under small *** this result,we can describe the stability of the non-autonomous dynamic systems.
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