Recently, two authentication schemes with anonymity for roaming service in wireless networks were proposed by He et al. and Xu et al. In this paper we point out that neither of the two schemes is sufficiently practica...
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Recently, two authentication schemes with anonymity for roaming service in wireless networks were proposed by He et al. and Xu et al. In this paper we point out that neither of the two schemes is sufficiently practical owing to the high computational cost involved. Furthermore, we also find that both schemes still have some weaknesses which allow the attacker to trace a certain user's behaviors and thus infer his real identity. Thereafter, we propose a novel lightweight authentication scheme with anonymity for roaming service in global mobility networks to overcome the aforementioned defects. Moreover, we formally analyze our proposed scheme with BAN-logic and show that it can withstand several possible attacks. Copyright (C) 2010 John Wiley & Sons, Ltd.
Concurrent calculi, such as CCS, are defined in terms of labelled transition system;similarly, here we introduce the notion of net (or distributed) calculus, which is defined through a place/transition Petri net. As a...
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Concurrent calculi, such as CCS, are defined in terms of labelled transition system;similarly, here we introduce the notion of net (or distributed) calculus, which is defined through a place/transition Petri net. As a first case study, a simple calculus of nets, called SCONE, is proposed, Relationships between SCONE and the subset of CCS without restriction and relabelling, called RCCS, are studied by showing that RCCS can be implemented in SCONE through a suitable mapping from the transition system for RCCS to net for SCONE. In particular, the complex CCS operation of global choice is implemented in terms of the SCONE finer grained operation of local choice, making explicit the fact that certain CCS transition are implemented as SCONE computations to be executed atomically. The result is a finite net implementation for RCCS agents. By making the quotient of the RCCS transition system w.r.t. the implementation mapping, we induce a truly concurrent semantics for RCCS. The second case study is then concerned with an extension dealing with restriction and relabelling. The resulting net calculus, called SCONE(+), is exploited as an implementation language for full CCS. The truly concurrent semantics induced by the implementation mapping is proved to coincide with the so-called ''permutation-of-transitions'' sematics.
We consider finite-temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of ...
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We consider finite-temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of the Gribov-Zwanziger quantization scheme, which entails the introduction of a dynamical mass scale (Gribov mass) directly influencing the Green functions of the theory. Here, we determine simultaneously the Polyakov loop (vacuum expectation value) and Gribov mass in terms of temperature, by minimizing the vacuum energy w.r.t. the Polyakov-loop parameter and solving the Gribov gap equation. Inspired by the Casimir energy-style of computation, we illustrate the usage of Zeta function regularization in finite-temperature calculations. Our main result is that the Gribov mass directly feels the deconfinement transition, visible from a cusp occurring at the same temperature where the Polyakov loop becomes nonzero. In this exploratory work we mainly restrict ourselves to the original Gribov-Zwanziger quantization procedure in order to illustrate the approach and the potential direct link between the vacuum structure of the theory (dynamical mass scales) and (de) confinement. We also present a first look at the critical temperature obtained from the refined Gribov-Zwanziger approach. Finally, a particular problem for the pressure at low temperatures is reported.
Magneto-electro-elastic (MEE) materials have been receiving a special attention from the research community owing to their specialized performance and coupled behavior under thermal, electric, magnetic and mechanical ...
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Magneto-electro-elastic (MEE) materials have been receiving a special attention from the research community owing to their specialized performance and coupled behavior under thermal, electric, magnetic and mechanical loads. The possibility of prospective energy conversion means, have additionally been added to the cause of researching about these materials. Therefore, the review presented here may be considered as a topical discussion on MEE materials and structures. Through this paper, all critical concepts revolving around MEE materials are discussed in separate sections ranging from the very definition of MEE materials, their material phenomenon, types and properties, to certain fundamental theories and micromechanical models, structural analyses of MEE structures and their nano-sized counterparts, effects of various external and internal parameters and prospective applications of these materials. The present study is in no ways exhaustive to the methods and results observed, but it may be considered as a guide to researchers and scholars about the behavior of MEE materials, wherein critical observations and analyses' techniques are discussed.
Several case studies show how dynamical systems methods can unearth nonintuitive modes of operation in the nervous system. The emphasis is on the detailed dynamics of cells and connections between them, which can have...
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Several case studies show how dynamical systems methods can unearth nonintuitive modes of operation in the nervous system. The emphasis is on the detailed dynamics of cells and connections between them, which can have major implications for how networks of neurons operate. How biological structure may be translated into mathematical structure, that can be exploited to help connect properties from cellular biophysics with network behavior, is illustrated.
The paper considers the minimum 3-connectivity augmentation problems: determining a minimum-weight set of edges to be added so as to 3-connect a given undirectted simple graph. The first result is that the problem is ...
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The paper considers the minimum 3-connectivity augmentation problems: determining a minimum-weight set of edges to be added so as to 3-connect a given undirectted simple graph. The first result is that the problem is NP-complete even if a given graph and weights are restricted to a 2-connected graph and either 1 or 2, respectively. The second result is for the problem with all weights are equal: it is shown that the cardinality of a solution to the problem can be computed from a given graph and that there is an O ( n v ( n v + n e ) 2 ) algorithm for finding a solution, where n v and n e are the numbers of vertices and edges of a given graph, respectively.
We consider the problem of taking advantage of existing order within the input sequence when sorting. The measure of presortedness used is the number of inversions. Let X be a sequence of length n and let Inv(X) be th...
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We consider the problem of taking advantage of existing order within the input sequence when sorting. The measure of presortedness used is the number of inversions. Let X be a sequence of length n and let Inv(X) be the (unknown) number of inversions in X. Our main results are: X can be sorted in-place, i.e. using only O(log n) bits of extra space, in time O(n log (Inv(X)/n)), which is optimal with respect to the number of inversions. Given p processors on an EREW PRAM, X can be sorted in time O(n log (Inv(X)/n)/p + log n), which is optimal with respect to the number of inversions.
Free boundary problems deal with systems of partial differential equations, where the domain boundaries are apriori unknown. Due to this special characteristic, it is challenging to solve free boundary problems either...
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Free boundary problems deal with systems of partial differential equations, where the domain boundaries are apriori unknown. Due to this special characteristic, it is challenging to solve free boundary problems either theoretically or numerically. In this paper, we develop a novel approach for solving a modified Hele-Shaw problem based on the neural network discretization. The existence of the numerical solution with this discretization is established theoretically. We also numerically verify this approach by computing the symmetry-breaking solutions which are guided by the bifurcation analysis near the radially-symmetric branch. Moreover, we further verify the capability of this approach by computing some non-radially symmetric solutions which are not characterized by any theorems.
We present a theory of even functionals of degree k. Even functionals are homogeneous polynomials which are invariant with respect to permutations and reflections. These are evaluated on real symmetric matrices. Impor...
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We present a theory of even functionals of degree k. Even functionals are homogeneous polynomials which are invariant with respect to permutations and reflections. These are evaluated on real symmetric matrices. Important examples of even functionals include functions for enumerating embeddings of graphs with k edges into a weighted graph with arbitrary (positive or negative) weights, and computing kth moments (expected values of kth powers) of a binary form. This theory provides a uniform approach for evaluating even functionals and links their evaluation with expressions that have matrices as operands. in particular, we show that any even functional of degree less than 7 can be computed in time sufficient to multiply two n x n matrices.
We show that the notion of sequentiality as presented in concrete data structures may be carried to a more general domain-theoretic framework. Cells are replaced by some linear maps on a domain which turns out to be a...
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We show that the notion of sequentiality as presented in concrete data structures may be carried to a more general domain-theoretic framework. Cells are replaced by some linear maps on a domain which turns out to be a DI-domain. In a first phase we do not require the cells to be enabled as they are in CDSs, and we get a weak form of cartesian-closedness. Then, by enriching the structure, we get the standard one.
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