On contradiction in fuzzy logic

 We clarify which space of functions in [0, 1] ^E would be reasonable in fuzzy logic in order to avoid self-contradiction.     

Rough fuzzy approximations on two universes of discourse

In rough set theory, the lower and upper approximation operators can be constructed via a variety of approaches. Various fuzzy generalizations of rough approximation operators have been made over the years. This paper presents a framework for the study of rough fuzzy sets on two universes of discourse. By means of a binary relation between two universes of discourse, a covering and three relations are induced to a single universe of discourse. Based on the induced notions, four pairs of rough fuzzy approximation operators are proposed. These models guarantee that the approximating sets and the approximated sets are on the same universes of discourse. Furthermore, the relationship between the new approximation operators and the existing rough fuzzy approximation operators on two universes of discourse are scrutinized, and some interesting properties are investigated. Finally, the connections of these approximation operators are made, and conditions under which some of these approximation operators are equivalent are obtained.     

Possible black universes in a brane world

A black universe is a nonsingular black hole where, beyond the horizon, there is an expanding, asymptotically isotropic universe. Such spherically symmetric configurations have been recently found as solutions to the Einstein equations with phantom scalar fields (with negative kinetic energy) as sources of gravity. They have a Schwarzschild–like causal structure but a de Sitter infinity instead of a singularity. It is attempted to obtain similar configurations without phantoms, in the framework of an RS2 type brane world scenario, considering the modified Einstein equations that describe gravity on the brane. By building an explicit example, it is shown that black–universe solutions can be obtained there in the presence of a scalar field with positive kinetic energy and a nonzero potential.     

Fuzzy finite element analysis of imprecisely defined structures with fuzzy nodal force

This paper presents the fuzzy finite element analysis for static displacements of fixed free stepped rectangular beam, truss and simplified bridge structure with fuzzy nodal force. The material and geometric properties of the structures are taken as crisp. Fuzzy finite element analysis of static problem for the above structures converts the problem into fuzzy system of linear equations. As such the coefficient matrix and the right-hand side vector become crisp and fuzzy respectively. A new approach is used here to solve the fuzzy system of linear equations. Numerical results for the three stepped rectangular beam, three-bar truss and simplified bridge with fifteen elements are presented to illustrate the computational aspects of the developed method. The results obtained are depicted in term of plots.     

Gravitational waves in singular and bouncing FLRW universes

We investigate propagation of gravitational waves in two models belonging to the Friedman-Lemaître-Robertson-Walker (FLRW) class of cosmologies: the singular Einstein-Maxwell Universe (EMU), which has an electromagnetic field described by Maxwell’s electrodynamics as the source of its geometry, and the bouncing Nonlinear Electrodynamics Universe (NLEU), which has the electromagnetic field described by a nonlinear generalization of Maxwell’s electrodynamics as the source of its geometry. We work with an explicitly gauge-independent formulation of cosmological perturbations in FLRW models and analyze the qualitative features of the dynamical system that describes the propagation of primordial tensorial perturbations in both geometries. Based on this analysis, we show that gravitational waves generated near a singularity or a bounce exhibit qualitatively different behavior.     

Analysis of families of hash functions defined by automata over a finite ring

Some general properties of families of hash functions defined by strongly connected automata without output function over a finite ring are analyzed. The probabilities of randomly choosing a sequence for which a hash function assumes a given value and also two different sequences of the same length for which the values of a hash function coincide. The computational security of the investigated hash-functions is characterized.     

Full hierarchical dependencies in fixed and undetermined universes

Full hierarchical dependencies (FHDs) constitute a large class of relational dependencies. A relation exhibits an FHD precisely when it is the natural join over at least two of its projections that all share the same join attributes. Therefore, FHDs generalise multivalued dependencies (MVDs) in which case the number of these projections is precisely two. The implication of FHDs has originally been defined in the context of some fixed finite universe. This paper identifies a sound and complete set of inference rules for the implication of FHDs. This axiomatisation is very reminiscent of that for MVDs. Then, an alternative notion of FHD implication is introduced in which the underlying set of attributes is left undetermined. The first main result establishes a finite axiomatisation for FHD implication in undetermined universes. It is then formally clarified that the complementation rule is only a mere means for database normalisation. In fact, the second main result establishes a finite axiomatisation for FHD implication in fixed universes which allows to infer FHDs either without using the complementation rule at all or only in the very last step of the inference. This also characterises the expressiveness of an incomplete set of inference rules in fixed universes. The results extend previous work on MVDs by Biskup.     

Nonsingular Chaplygin gas cosmologies in universes connected by a wormhole

We present some exact solutions of the Einstein equations with an anisotropic fluid exploiting the Chaplygin equation of state. The solutions describe space-times with two identical T-regions and an intermediate static spherically symmetric R-region containing a wormhole. The metric in the T-region represents an anisotropic Kantowski-Sachs cosmological model. Its evolution starts from a horizon and develops according to different scenarios including eternal expansion, contraction and also a finite lifetime.     

Measuring and reducing axial motion of flat belt by finite element analysis

A simulation method for estimating and reducing axial motion of flat belt is developed by using a commercial finite element (FE) code, MARC. The simulated results of the axial motion rate have good agreement with the experimental ones. This research further shows that the axial motion of flat belt can effectively be reduced by setting an added steering roller to center position of the belt loosen span. Observing the deflected configuration of belt centerline and its expanded shape on two roller surfaces, we find a phenomenon that the belt wraps on the roller surface spirally and rotates with the roller without slippage. The mechanism of the belt axial motion is clarified in this paper.     

Some inequalities for probability,expectation, and variance of random variables defined over a finite interval

Some recent inequalities for cumulative distribution functions, expectation, variance, and applications are presented.     

信息安全专业课程中协作对抗教学法的应用研究

本文首先分析了信息安全课程体系和目前的教学方法和培养模式的不足之处;然后阐述了基于建构主义学习理论的协作对抗教学法;最后以“蠕虫病毒”部分内容为例,详细描述了协作对抗教学法在信息安全专业的一门重要课程“计算机病毒”中的教学示范及步骤流程。     

Exploring complexity and contradiction in information technology outsourcing: A set-theoretical approach

Effectively managing Information Technology outsourcing (ITO) requires integration of conceptually distinct and sometimes contradicting factors. For instance, ITO “best practices” for cost reduction can inhibit a firm’s innovativeness. To address these challenges, we build on governance and capability perspectives and employ a set-theoretic approach to examine ITO practices in 27 firms. Our exploratory study reveals four distinct ITO configurations, of which three lead to positive outcomes and one leads to negated-outcomes. Detailed contracts appear to be a necessary condition for cost reduction but can also be an impediment to strategic innovation; and firms can consider a “best-of-breed” strategy to overcome this tension. Our findings call for more attention to both transaction-based and portfolio-based governance to enable flexibility for innovation while retaining rigor and risk mitigation for cost reduction.