On normal-valued basic pseudo-hoops

We show that every pseudo-hoop satisfies the Riesz decomposition property. We visualize basic pseudo-hoops by functions on a linearly ordered set. Finally, we study normal-valued basic pseudo-hoops giving a countable base of equations for them.     

R0代数中的模糊正规滤子

在R₀代数中引入模糊正规滤子的概念,给出其充要条件,得到了模糊正规滤子的扩张性质,讨论了模糊正规滤子与模糊滤子、截集之间的关系,最后,用模糊正规滤子刻画了正规R₀代数M和正规商R₀代数M/f。     

On exact filters for continuous signals with discrete observations

Many filtering applications have continuous state dynamics X_t =∫₀^tm(X_s)ds+σW_t +ρ, discrete observations Y_j=Y(t_j), and nonadditive or non-Gaussian observation noise. One wants to calculate the conditional probability Pr{Xt∈dz|Y_j, 0⩽t_j ⩽t} economically. In this paper we show that a combination of convolution, scaling, and substitutions efficiently solves this problem under certain conditions. Our method is easy to use and assumes nothing about the observations other than the ability to construct p(Y_j )|X(t_j), the conditional density of the jth observation given the current state     

On the maximal connected component of hypercube with faulty vertices

In evaluating an interconnection network, it is indispensable to estimate the size of the maximal connected components of the underlying graph when the network begins to lose processors. Hypercube is one of the most popular interconnection networks. This article addresses the maximal connected components of an n-dimensional cube with faulty processors. We first prove that an n-cube with a set F of at most 2n???3 failing processors has a component of size ≥2 ⁿ ???|F|???1. We then prove that an n-cube with a set F of at most 3n???6 missing processors has a component of size ≥2 ⁿ ???|F|???2.     

On the maximal order in PC-codes

It is shown thatk-step PC-algorithms suffer from relative instability for systems with positive eigenvalues, at higher values ofk. This sets a natural boundary on the useful values ofk.     

On maximal deviation of linear system

An analytical solution of the B.V. Bulgakov problem of maximum of the norm of finite state of the stationary linear system with one control (perturbation) function taking values over an interval was proposed. The switching function of the worst relay perturbation was shown to depend on time and coordinates and be the product of the phase system vector, its transition matrix transposed to it, and the transposed column of the coefficients at perturbation.     

On maximal repetitions of arbitrary exponent

The first two authors have shown [1,2] (Kolpakov and Kucherov, 1999, 2000) that the sum of the exponents (and thus the number) of maximal repetitions of exponent at least 2 in a word (also called runs) is linear with respect to the length of the word. The exponent 2 in the definition of a run may seem arbitrary. In this paper, we consider maximal repetitions of exponent strictly greater than 1.     

On graphs with the third largest number of maximal independent sets

Let G be a simple and undirected graph. By mi(G) we denote the number of maximal independent sets in G. Erd?s and Moser posed the problem to determine the maximum cardinality of mi(G) among all graphs of order n and to characterize the corresponding extremal graphs attaining this maximum cardinality. The above problem has been solved by Moon and Moser in [J.W. Moon, L. Moser, On cliques in graphs, Israel J. Math. 3 (1965) 23-28]. More recently, Jin and Li [Z. Jin, X. Li, Graphs with the second largest number of maximal independent sets, Discrete Mathematics 308 (2008) 5864-5870] investigated the second largest cardinality of mi(G) among all graphs of order n and characterized the extremal graph attaining this value of mi(G). In this paper, we shall determine the third largest cardinality of mi(G) among all graphs G of order n. Additionally, graphs achieving this value are also determined.     

On 3rd order ordinary differential equations with maximal symmetry group

The following theorem is proved by investigating the Janet bases of determining systems: In order that a 3^rd order quasilinear ordinary differential equation has a seven-parameter symmetry group it must have a certain structure, and a set of necessary and sufficient conditions for its coefficients must be satisfied. This theorem generalizes similar results for linear equations and for quasilinear equations of 2^nd order. It is shown how this theorem facilitates the computation of closed form solutions.     

On finding cycle bases and fundamental cycle bases with a shortest maximal cycle

An undirected biconnected graph G with nonnegative integer lengths on the edges is given. The problem we consider is that of finding a cycle basis B of G such that the length of the longest cycle included in B is the smallest among all cycle bases of G. We first observe that Horton's algorithm [SIAM J. Comput. 16 (2) (1987) 358-366] provides a fast solution of the problem that extends the one given by Chickering et al. [Inform. Process. Lett. 54 (1995) 55-58] for uniform graphs. On the other hand we show that, if the basis is required to be fundamental, then the problem is NP-hard and cannot be approximated within 2−?, ∀?>0, even with uniform lengths, unless P=NP. This problem remains NP-hard even restricted to the class of complete graphs; in this case it cannot be approximated within 13/11−?, ∀?>0, unless P=NP; it is instead approximable within 2 in general, and within 3/2 if the triangle inequality holds.     

On multiple-model extended target multi-Bernoulli filters

In this paper, we propose a multiple-model (MM) version of the extended target multi-Bernoulli (ET-MB) filter for estimating multiple maneuvering extended targets. A Gaussian mixture (GM) implementation of the MM-ET-MB filter for linear Gaussian models and a sequential Monte Carlo (SMC) implementation of the MM-ET-MB filter for nonlinear models are presented. Two numerical examples are provided to verify the effectiveness of the MM-ET-MB filter for estimating multiple maneuvering extended targets.     

On disjoint maximal independent sets in graphs

An old problem in graph theory is to characterize the graphs that admit two disjoint maximal independent sets.     

On morphological operators based on rank filters

Rank order morphological operators have been designed to better cope with shape variations and noise than the corresponding operators with plain structuring elements. In this paper, starting from a brief historical overview of rank order filters and erosions/dilations in digital image processing, rank order based morphological operators are surveyed. We also highlight the relations between these operators and show that many are similar if not equivalent. An extensive bibliography is provided.     

On the false-positive rate of Bloom filters

Bloom filters are a randomized data structure for membership queries dating back to 1970. Bloom filters sometimes give erroneous answers to queries, called false positives. Bloom analyzed the probability of such erroneous answers, called the false-positive rate, and Bloom's analysis has appeared in many publications throughout the years. We show that Bloom's analysis is incorrect and give a correct analysis.     

On asymptotic stability of continuous-time risk-sensitive filters with respect to initial conditions

In this paper, we consider the problem of risk-sensitive filtering for continuous-time stochastic linear Gaussian time-invariant systems. In particular, we address the problem of forgetting of initial conditions. Our results show that suboptimal risk-sensitive filters initialized with arbitrary Gaussian initial conditions asymptotically approach the optimal risk-sensitive filter for a linear Gaussian system with Gaussian but unknown initial conditions in the mean square sense at an exponential rate, provided the arbitrary initial covariance matrix results in a stabilizing solution of the (H_∞-like) Riccati equation associated with the risk-sensitive problem. More importantly, in the case of non-Gaussian initial conditions, a suboptimal risk-sensitive filter asymptotically approaches the optimal risk-sensitive filter in the mean square sense under a boundedness condition satisfied by the fourth order absolute moment of the initial non-Gaussian density and a slow growth condition satisfied by a certain Radon–Nikodym derivative.     

On the maximal connected component of hypercube with faulty vertices (II)

In evaluating the fault tolerance of an interconnection network, it is essential to estimate the size of a maximal connected component of the network at the presence of faulty processors. Hypercube is one of the most popular interconnection networks. In this paper, we prove that for n?≥?6, an n-dimensional cube with a set F of at most (4n???10) failing processors has a component of size ≥2″???|F|???3. This result demonstrates the superiority of hypercube in terms of the fault tolerance.