with the best possible constant factors
This improves a recently published result of Cerone et al., J. Inequalities Pure Appl. Math. 5(2) (43) (2004), who showed that the double-inequality holds with and .  相似文献   

18.
    
《Electronic Notes in Discrete Mathematics》2013
In this paper, we consider the Capacitated Network Design (CND) problem. We investigate the relationship between CND and the Bin-Packing problem. This is exploited for identifying new classes of valid inequalities for the CND problem and developing a branch-and-cut algorithm to solve it efficiently.  相似文献   

19.
Some Sharpening and Generalizations of a Result of T. J. Rivlin     
N. K. Govil  Eze R. Nwaeze 《分析论及其应用》2017,33(3)
Let p(z)=a_0+a_1z+a_2z~2+a_3z~3+···+a_nz~n be a polynomial of degree n.Rivlin[12]proved that if p(z)≠0 in the unit disk,then for 0r≤1,max|z|=r|p(z)|≥((r+1)/2)~nmax|p(z)||z|=1.In this paper,we prove a sharpening and generalization of this result and show by means of examples that for some polynomials our result can significantly improve the bound obtained by the Rivlin’s Theorem.  相似文献   

20.
    
《The Journal of Mathematical Behavior》2021
Inequalities are an important topic in school mathematics, yet the body of research exploring students’ meanings for inequalities largely points to difficulties they experience. Thus, there is a need to further explore students’ meanings for inequalities. Addressing this need, we conducted an exploratory teaching experiment with two seventh-grade students to investigate their developing meanings for inequalities. We distinguish between two types of inequalities in student thinking: comparative and restrictive inequalities. Whereas a student reasoning about a comparative inequality compares two quantities’ values or magnitudes, reasoning about a restrictive inequality entails reasoning about a range of one quantity’s magnitudes or values. We realized a complexity arose in our interactions with students due to our conceiving the use of inequality symbols across the two types of inequalities as polysemous, whereas the students did not. Attending to these two types of inequalities has important implications for the teaching and learning of inequality.  相似文献   

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For the past few years, the increase in high bandwidth requiring services forced telecommunication operators like France Telecom - Orange to engage the deployment of optical networks, the Fiber To The Home Gigabit Passive Optical Network (FTTH GPON) technology, leading to new design problems. Such problems have already been studied. However, to the best of our knowledge, without taking into account the future demand uncertainty. In this paper, we propose a model for a two-stage robust optimization FTTH network design problem tackling the demand uncertainty. We propose an exact algorithm, based on column and constraint generation algorithms, and we show some preliminary results.  相似文献   

3.
This paper introduces a formulation for the Minimum Dominating Cycle Problem. Additionally, a Branch and Cut algorithm, based on that formulation, is also investigated. So far, the algorithm contains no primal heuristics. However, it managed to solve to proven optimality, in acceptable CPU times, all test instances with up to 120 vertices.  相似文献   

4.
We present a new robust optimization model for the problem of maximizing the amount of flow surviving the attack of an interdictor. Given some path flow, our model allows the interdictor to specify the amount of flow removed from each path individually. In contrast to previous models, for which no efficient algorithms are known, the most important basic variants of our model can be solved in poly-time. We also consider extensions where there is a budget to set the interdiction costs.  相似文献   

5.
It is well-known how to use maximum flow to decide when a flow problem with demands, lower bounds, and upper bounds is infeasible. Less well-known is how to compute a flow that is least infeasible. This paper considers many possible ways to define “least infeasible” and shows how to compute optimal flows for each definition. For each definition it also gives a dual characterization in terms of cuts, a polynomial routine for recognizing that type of least infeasible flow, and relates that definition to dual cut canceling min-cost flow network algorithms. This research was partially supported by an NSERC Operating Grant, an NSERC Grant for Research Abroad, and a UBC Killam Faculty Study Leave Fellowship. Parts of this research were done while the author was visiting Laboratoire ARTEMIS IMAG at Université Joseph Fourier de Grenoble, France.  相似文献   

6.
本文用“稳健设计”的观点,分别对OTL电路中点电压稳定性“系统择优”,“参数择优”及“容差择优”作出较为系统的介绍  相似文献   

7.
    
The Maximum Robust Flow problem asks for a flow on the paths of a network maximizing the guaranteed amount of flow surviving the removal of any k arcs. We point out a flaw in a previous publication that claimed NP-hardness for this problem when k=2. For the case that k is part of the input, we present a new hardness proof. We also discuss the complexity of the integral version of the problem.  相似文献   

8.
This paper considers a special case of the robust network design problem where the dominant extreme points of the demand polyhedron have a disjoint support. In this case static and dynamic routing lead to the same optimal solution, both for the splittable and the unsplittable case. As a consequence, the robust network design problem with (splittable) dynamic routing is polynomially solvable, whereas it is co-NP-hard in the general case. This result applies to particular instances of the single-source Hose model.  相似文献   

9.
    
There are many applications of max flow with capacities that depend on one or more parameters. Many of these applications fall into the “Source-Sink Monotone” framework, a special case of Topkis's monotonic optimization framework, which implies that the parametric min cuts are nested. When there is a single parameter, this property implies that the number of distinct min cuts is linear in the number of nodes, which is quite useful for constructing algorithms to identify all possible min cuts.When there are multiple Source-Sink Monotone parameters, and vectors of parameters are ordered in the usual vector sense, the resulting min cuts are still nested. However, the number of distinct min cuts was an open question. We show that even with only two parameters, the number of distinct min cuts can be exponential in the number of nodes.  相似文献   

10.
Sustainable product design has been considered as one of the most important practices for achieving sustainability. To improve the environmental performances of a product through product design, however, a firm often needs to deal with some difficult technical trade-offs between traditional and environmental attributes which require new design concepts and engineering specifications. In this paper, we propose a novel use of the two-stage network Data Envelopment Analysis (DEA) to evaluate sustainable product design performances. We conceptualize “design efficiency” as a key measurement of design performance in terms of how well multiple product specifications and attributes are combined in a product design that leads to lower environmental impacts or better environmental performances. A two-stage network DEA model is developed for sustainable design performance evaluation with an “industrial design module” and a “bio design module.” To demonstrate the applications of our DEA-based methodology, we use data of key engineering specifications, product attributes, and emissions performances in the vehicle emissions testing database published by the US EPA to evaluate the sustainable design performances of different automobile manufacturers. Our test results show that sustainable design does not need to mean compromise between traditional and environmental attributes. Through addressing the interrelatedness of subsystems in product design, a firm can find the most efficient way to combine product specifications and attributes which leads to lower environmental impacts or better environmental performances. This paper contributes to the existing literature by developing a new research framework for evaluating sustainable design performances as well as by proposing an innovative application of the two-stage network DEA for finding the most eco-efficient way to achieve better environmental performances through product design.  相似文献   

11.
We give an inequality which bounds the product of the Lp norms of the linear factors of a polynomial by a multiple of the Lp norm of that polynomial. This result generalizes two inequalities of Króo and Pritsker.  相似文献   

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After an introduction to main ideas of semi-infinite optimization, this article surveys recent developments in theory and numerical methods for standard and generalized semi-infinite optimization problems. Particular attention is paid to connections with mathematical programs with complementarity constraints, lower level Wolfe duality, semi-smooth approaches, as well as branch and bound techniques in adaptive convexification procedures. A section on recent genericity results includes a discussion of the symmetry effect in generalized semi-infinite optimization.  相似文献   

15.
研究了新的一类模糊映射的广义混合型强变分不等式问题。证明了这类问题解的存在定理和收敛定理,给出解的带误差的Ishikawa型迭代算法。  相似文献   

16.
For an arbitrary entire functionf and anyr>0, letM(f,r):=max|z|=r |f(z)|. It is known that ifp is a polynomial of degreen having no zeros in the open unit disc, andm:=min|z |=1|p(z)|, then
It is also known that ifp has all its zeros in the closed unit disc, then
. The present paper contains certain generalizations of these inequalities.  相似文献   

17.
Let ζ be the Riemann zeta function and δ(x)=1/(2x-1). For all x>0 we have
(1-δ(x))ζ(x)+αδ(x)<ζ(x+1)<(1-δ(x))ζ(x)+βδ(x),
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