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1.
Advertising is the basic source of income for many web businesses. Preparing website layout for the advertisements is a problem faced by many web designers. The ads and other content are placed in several columns. Usually column widths are chosen ad hoc to fit the widest advertising unit. To make a more informed decisions website column width selection is formulated in this paper as optimization problem. A method of selecting column widths for a given set of advertisement units is proposed. Ad unit combinations that fit the given column widths are generated by the improved Wang algorithm for two-dimensional stock cutting problem. Column widths are evaluated for several objective functions. Two approaches are proposed. The first constructs a Pareto frontier of column width combinations. The second calculates the optimum column widths with respect to a weighted linear function of the objectives. To justify the weights expert survey was conducted. Both approaches are examined on datasets of internet advertising units.  相似文献   

2.
Order estimates are obtained for the Kolmogorov, linear, and Gel’fand widths of the image of the unit ball of the space lp under the action of a two-weight summation operator with weights of special kind. Some limit conditions on the parameters defining the weights are considered.  相似文献   

3.
连续偏序集及其Smyth幂的几个等权定理   总被引:2,自引:1,他引:1  
推广连续D om a in的权的概念到连续偏序集上,探讨连续偏序集的权、相应内蕴拓扑的权、定向完备化的权以及Sm yth幂D om a in的权间的关系。得到了几个等权定理:(1)连续偏序集的权与其上Scott拓扑、L aw son拓扑的权相等;(2)连续偏序集的权与其定向完备化的权相等;(3)无穷连续D om a in的权与其Sm yth幂D om a in的权相等;(4)有限D om a in的权小于或等于它的Sm yth幂D om a in的权。  相似文献   

4.
We prove boundary asymptotics to solutions of weighted p-Laplacian equations that take infinite value on the boundary of a bounded domain. Uniqueness of such solutions would then follow as a consequence. Our results extend previously known results by allowing weights that are unbounded in the domain.  相似文献   

5.
《Fuzzy Sets and Systems》2007,158(17):1913-1921
In analytic hierarchy process (AHP) structured hierarchically as several criteria and alternatives, the priority of an alternative is obtained by using the pairwise comparisons based on a decision maker's intuition. Thus, the given comparisons are uncertain and inconsistent with each other. We use the interval approach for obtaining interval evaluations which are suitable for handling uncertain data. Since the given comparisons are ratio measures and too large intervals are not useful information, the intervals should be normalized and their redundancy should be reduced. We introduce interval probability which fills the role of interval normalization instead of crisp normalization in the estimations at each hierarchy. Then, as a final decision, the interval global weights reflecting the decision maker's uncertain judgements as their widths without redundancy are obtained.  相似文献   

6.
New embeddings of some weighted Sobolev spaces with weights a(x)and b(x)are established.The weights a(x)and b(x)can be singular.Some applications of these embeddings to a class of degenerate elliptic problems of the form-div(a(x)?u)=b(x)f(x,u)in?,u=0 on??,where?is a bounded or unbounded domain in RN,N 2,are presented.The main results of this paper also give some generalizations of the well-known Caffarelli-Kohn-Nirenberg inequality.  相似文献   

7.
We study a class of fractional p-Laplacian problems with weights which are possibly singular on the boundary of the domain. We provide existence and multiplicity results as well as characterizations of critical groups and related applications.  相似文献   

8.
The existence of a compact random attractor for the stochastic complex Ginzburg–Landau equation with multiplicative noise has been investigated on unbounded domain. The solutions are considered in suitable spaces with weights. According to crucial properties of Ornstein–Uhlenbeck process, using the tail-estimates method, the key uniform a priori estimates for the tail of solutions have been obtained, which give the asymptotic compactness of random attractors. Then the existence of a compact random attractor for the corresponding dynamical system is proved in suitable spaces with weights.  相似文献   

9.
For smooth functions supported in a domain of the Euclidean space we investigate two Rellich type inequalities with weights which are powers of the distance function. We prove that for an arbitrary plane domain there exist positive Rellich constants in these inequalities if and only if the boundary of the domain is a uniformly perfect set. Moreover, we obtain explicit estimates of constants in function of geometric domain characteristics. Also, we find sharp constants in these Rellich type inequalities for all non-convex domains of dimension d ≥ 2 provided that the domains satisfy the exterior sphere condition with certain restriction on the radius of spheres.  相似文献   

10.
We present a program for computing symmetric quadrature rules on triangles and tetrahedra. A set of rules are obtained by using this program. Quadrature rules up to order 21 on triangles and up to order 14 on tetrahedra have been obtained which are useful for use in finite element computations. All rules presented here have positive weights with points lying within the integration domain.  相似文献   

11.
Using a variational approach, we investigate a class of degenerate semilinear elliptic systems with measurable, unbounded nonnegative weights, where the domain is bounded or unbounded. Some existence results are obtained.  相似文献   

12.
This paper proposes a novel hybrid algorithm for automatic selection of the proper input variables, the number of hidden nodes of the radial basis function (RBF) network, and optimizing network parameters (weights, centers and widths) simultaneously. In the proposed algorithm, the inputs and the number of hidden nodes of the RBF network are represented by binary-coded strings and evolved by a genetic algorithm (GA). Simultaneously, for each chromosome with fixed inputs and number of hidden nodes, the corresponding parameters of the network are real-coded and optimized by a gradient-based fast-converging parameter estimation method. Performance of the presented hybrid approach is evaluated by several benchmark time series modeling and prediction problems. Experimental results show that the proposed approach produces parsimonious RBF networks, and obtains better modeling accuracy than some other algorithms.  相似文献   

13.
We establish Blackwell-type theorems for weighted renewal functions under much weaker conditions, as compared to the available, on the weight sequence and the distributions of the jumps in the renewal process. The proofs are based on using integro-local limit theorems and large deviation bounds. For the jump distribution, we consider conditions of the four types: (a) it has finite second moment, (b) it belongs to the domain of attraction of a stable law, (c) its tails are locally regularly varying, and (d) it satisfies the moment Cramér condition. In cases (a)–(c), the weights are assumed to satisfy a broad regularity condition on their moving averages, whereas in case (d) the weights can change exponentially fast.  相似文献   

14.
We give an upper bound for the deviation of the norm of a perturbed error from the norm of the original error of a cubature formula in a multidimensional bounded domain. The deviation arises as a result of the joint influence on the computations of small variations of the weights of a cubature formula and rounding in the subsequent calculations of the cubature sum in the given standards (formats) of approximation to real numbers. We estimate the practical error of a cubature formula acting on an arbitrary function from the unit ball of a normed space of integrands. The resulting estimates are applied to studying the practical error of cubature formulas in the case of integrands in Sobolev spaces on a multidimensional cube. The norm of the error in the dual space of the Sobolev class is represented as a positive definite quadratic form in the weights of the cubature formula. We estimate the practical error for cubature formulas constructed as the direct product of quadrature formulas of rectangles along the edges of the unit cube. The weights of this direct product are positive.  相似文献   

15.
Using an example of two coupled waveguides, we construct a periodic second-order differential operator acting in a Euclidean domain and having spectral gaps whose edges are attained strictly inside the Brillouin zone. The waveguides are modeled by the Laplacian in two infinite strips of different width that have a common interior boundary. On this common boundary, we impose the Neumann boundary condition, but cut out a periodic system of small windows, while on the remaining exterior boundary we impose the Dirichlet boundary condition. It is shown that, by varying the widths of the strips and the distance between the windows, one can control the location of the extrema of the band functions as well as the number of the open gaps. We calculate the leading terms in the asymptotics for the gap lengths and the location of the extrema.  相似文献   

16.
The spaces dual to spaces of holomorphic functions of given growth on Carathéodory domains are described by using the Cauchy transform of functionals. A pseudoanalytic extension of such transforms to the whole plane is constructed, which makes it possible to remove convexity constrains and consider spaces determined by weights of general form, rather than only by those whose dependence on the distance from a point of the domain to its boundary is one-dimensional.  相似文献   

17.
Wang Yunlong 《Acta Appl Math》2010,110(3):1037-1056
A new function is found and is defined as sinc sum function by the author. It has outstanding properties of stairs shape, global symmetry, local symmetry, derivative formula simplicity, local extreme certainty, oscillation regularity, extreme value stability, etc. These properties are proved. Geometry meaning is explained. As an application of the function, the author has developed a new method to design FIR digital filters with adjustable weights. Filter formula in time domain is the weighted sum of sub-filters. A novel form of frequency response expression is deduced which is the sum of sinc sum functions. One of the remarkable characteristics of the form is that weights of sub-filters can be directly calculated according to the expression. Completing the calculation of the weights means finishing the design of a filter. The weights can be either adjustable or fixed. A method to determine the weights are given. Three examples using the method are selected for the consideration that the new method can be easily compared with some famous window methods. Three new filter formulas are produced. Much better performances can be obtained using these formulas compared with using Hanning window and Blackman window respectively. And the performance designing with the new method is slightly better than that with Hamming window. For fixed weights it is almost as easy as using fixed window to calculate filter coefficients.  相似文献   

18.
We present five new cubature formula in the triangle and square for exact integration of polynomials. The points were computed numerically with a cardinal function algorithm which does not impose any symmetry requirements on the points. Cubature formula are presented which integrate degrees 10, 11 and 12 in the triangle and degrees 10 and 12 in the square. They have positive weights, contain no points outside the domain, and have fewer points than previously known results.  相似文献   

19.
The best uniform approximation of a segment function on an interval by a polynomial strip of fixed width (in ordinate) with respect to the Hausdorff measure at each point of the interval is considered. Ranges of strip widths are indicated for which this problem gives outer and inner estimates for the graph of the segment function in terms of the polynomial strip, and a range of strip widths is given for which the problem has an independent value. A necessary and sufficient condition for the existence of a solution and uniqueness conditions are obtained in a form comparable to the Chebyshev alternance. A range of strip widths is indicated for which the solution of the problem is always unique. Certain variational properties of the solution are examined.  相似文献   

20.
Generalizations of the Trudinger–Moser inequality to Sobolev spaces with singular weights are considered for any smooth domain Ω???? N . Furthermore, we show that the resulting inequalities are sharp obtaining the best exponents.  相似文献   

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