Some Geometric Inequalities for a Tangent Point Simplex

The tangent point simplex of a simplex is the pedal simplex of the incenter of . In this paper we obtain some geometric inequalities between and .     

涉及单形内点的几何不等式

建立了涉及n维单形内点的两个几何不等式，作为其特例得到n维Euler不等式的推广。     

An Arbitrary Starting Variable Dimension Algorithm for Computing an Integer Point of a Simplex

An arbitrary starting variable dimension algorithm is proposed to compute an integer point of an n-dimensional simplex. It is based on an integer labeling rule and a triangulation of Rⁿ. The algorithm consists of two interchanging phases. The first phase of the algorithm is a variable dimension algorithm, which generates simplices of varying dimensions,and the second phase of the algorithm forms a full-dimensional pivoting procedure, which generates n-dimensional simplices. The algorithm varies from one phase to the other. When the matrix defining the simplex is in the so-called canonical form, starting at an arbitrary integer point, the algorithm within a finite number of iterations either yields an integer point of the simplex or proves that no such point exists.     

一道习题的几何解法

从几何角度分析一道高等数学习题,指出所求的点的几何特征,给出了基于几何思想的解法.     

A Geometric Approach to Global Optimization

In this paper we consider the problem of optimizing a piecewise-linear objective function over a non-convex domain. In particular we do not allow the solution to lie in the interior of a prespecified region R. We discuss the geometrical properties of this problems and present algorithms based on combinatorial arguments. In addition we show how we can construct quite complicated shaped sets R while maintaining the combinatorial properties.     

A Geometric Approach to Acyclic Orientations

The set of acyclic orientations of a connected graph with a given sink has a natural poset structure. We give a geometric proof of a result of Jim Propp: this poset is the disjoint union of distributive lattices.     

Two Projection Algorithms for Solving the Split Common Fixed Point Problem

Journal of Optimization Theory and Applications - We study the split common fixed point problem for Bregman relatively nonexpansive operators in real reflexive Banach spaces. Using Bregman...     

半球面上一个几何优化问题

单位球面x2+ y2+ z2=1的赤道上(z=0)任意给定不同的三点A,B,C,求上半球面上(z≥0)上的一点D,使得距离和|AD|+|BD|+|CD|取得最大值.通过数值搜索知道,使距离和取得最大值的点D很多情况下位于赤道上,少数情况下位于半球面内部.通过角度计算,同时借助计算机辅助推导,发现了点D在大多数情况下位于...     

A New Approach to a Multicriteria Optimization Problem

We present a new approach to a multicriteria optimization problem, where the objective and the constraints are linear functions. From an equivalent equilibrium problem, first suggested in [5,6,8], we show new characterizations of weakly efficient points based on the partial order induced by a nonempty closed convex cone in a finite-dimensional linear space, as in [7]. Thus, we are able to apply the analytic center cutting plane algorithm that finds equilibrium points approximately, by Raupp and Sosa [10], in order to find approximate weakly efficient solutions of MOP.     

有关度量加单形宽度的不等式

本文利用距离几何理论和解析不等式的技巧,研究了度量加单形的宽度度量估计,建立了有关度量加单形宽度之间的几个几何不等式.     

涉及单形内一点和内外径的一类不等式

设 n维 Euclid空间 En(n≥ 2 )中单形 Ω(A)的顶点集为 A={ A0 ,A1,… ,An} .,Ω(A)内任一点 P至侧面 { A0 ,A1,… ,An} \{ Ai}的距离为 di(i=0 ,1,… ,n) ,Ω(A)的外接超球半径和内切超球半径分别为 R、r,记C( n,α) =(2 (n+ 1　 2 ) + (n+ 1) 2α- (n+ 1) α) / 4 (n+ 12 ) ) α(α≥ 1) ,本文建立了涉及Ω (A)内一点的不等式∑0≤ i相似文献   

Observation,Character, and A Purely First-Person Point of View

In Values and the Reflective Point of View (2006), Robert Dunn defends a certain expressivist view about evaluative beliefs from which some implications about self-knowledge are explicitly derived. He thus distinguishes between an observational and a deliberative attitude towards oneself, so that the latter involves a purely first-person point of view that gives rise to an especially authoritative, but wholly non-observational, kind of self-knowledge. Even though I sympathize with many aspects of Dunn's approach to evaluative beliefs and also with his stress on the practical significance of self-knowledge, I argue that his proposal seriously misinterprets the role of observation and evidence within the first-person point of view and, derivatively, in the formation of evaluative beliefs.     

A Eudaimonist Approach to the Problem of Significance

Some beliefs seem more significant than others. This paper suggests an approach to explaining this apparent fact. As there are multiple senses in which one belief may be more significant than another, multiple possible sources of such significance, and, moreover, no prima facie reason to expect a single, unified account under which all these senses and sources can be subsumed, I propose the modest approach of articulating just one feature in virtue of which a belief may fairly be called significant: that of bearing a certain relation to human flourishing, a relation that more trivial truths do not bear. From such modest projects can a complete solution to the problem (or, more accurately, problems) of significance emerge.     

A Constraint Satisfaction Approach to a Circuit Design Problem

A classical circuit-design problem from Ebers and Moll (1954) features a system of nine nonlinear equations in nine variables that is very challenging both for local and global methods. This system was solved globally using an interval method by Ratschek and Rokne (1993) in the box [0, 10]⁹. Their algorithm had enormous costs (i.e., over 14 months using a network of 30 Sun Sparc-1 workstations) but they state that ‘at this time, we know no other method which has been applied to this circuit design problem and which has led to the same guaranteed result of locating exactly one solution in this huge domain, completed with a reliable error estimate’. The present paper gives a novel branch-and-prune algorithm that obtains a unique safe box for the above system within reasonable computation times. The algorithm combines traditional interval techniques with an adaptation of discrete constraint-satisfaction techniques to continuous problems. Of particular interest is the simplicity of the approach. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Point Process Approach to Filtered Processes

We consider some models of filtered point processes such as those developped in Yue and Hashino (2001), and rephrase them in terms of point processes. We derive from this formulation some estimates for the probability of overflow in a rainfall process. This method allows us by considering a non deterministic model of filtering to compute some characteristics of the compound models of Cowpertwait (1994), Phelan (1991), and Rodriguez-Iturbe et al. (1987, 1988). A spatial version of this point process is also studied, using an analogy with the boolean model of stochastic geometry we compute bounds for the probability of dryness in a compound rainfall process.     

A Distribution- Theoretic Approach to a Stability Problem of Orr

In a classic paper [1] of 1907, W. M'Farr Orr discovered, among other things, the “infinitesimal” instability of inviscid plane Couette flow. Surprisingly, although Orr's paper remains a standard reference in the field, later investigators [2, 3] have been able to call inviscid plane Couette flow stable without finding it necessary to controvert Orr's result. What has happened is that, at least in problems governed by linear (or linearized) equations with time-independent coefficients, the term “instability” has come to be identified with the presence of solutions exhibiting exponential time-growth. Orr found instability indeed: a class of solutions certain members of which grow in time by more than each preassigned factor. Unlike the exponential instabilities, however, Orr's solutions die away like 1/t after achieving their greatest growth. This ephemerality probably accounts for the discounting of Orr's result. Orr did not look into the general initial value problem. This is done in the sequel, with the result that the situation becomes clear. Under general disturbances, Couette flow turns out to be neither stable nor quasi-asymptotically stable*. The rate of growth depends on the smoothness of the initial data: classical solutions grow no faster than t, but sufficiently rough distribution-valued initial data leads to growth matching any power of t. Before presenting detailed results, we briefly review Orr's fundamental work on the problem.     

A New Approach to the Delta Wing Problem

The "delta-wing problem" involves a solution of Laplace's equationnear the apex of an infinite sector, subject to certain boundaryconditions; it is known that the solution involves r^v wherer is the distance from the apex and v is a parameter dependingon the angle of the sector. The core of the problem is the determinationof v. This paper gives a new approach, based on the use of ellipticconal coordinates, and the solution of the resulting Laméequation by a new perturbation technique.     

A Three-Phase Approach to Solving the Bidline Problem

This paper describes a three-phase approach to solving the bidline generation problem within airline flightcrew scheduling. Phase 1 builds “patterns” from existing pairings. Phase 2 builds bidlines from the “patterns” found in Phase 1 and solves a set partitioning problem to generate a final schedule. If Phase 2 fails to cover enough of the scheduled work, Phase 3 is used to fill in the uncovered pairings. Along with this methodology is a new rule set that tries to improve the work–rest schedule for flightcrews by trying to take into account circadian rhythms. This new rule set is an attempt at addressing some of the flightcrews's quality of life issues.     

A Polytope Approach to the Optimal Assembly Problem

The problem of assembling components into series modules to maximize the system reliability has been intensively studied in the literature. Invariably, the methods employed exploit special properties of the reliability function through standard analytical optimization techniques. We propose a geometric approach by exploiting the assembly polytope – a polytope generated by the potential assembly configurations. The new approach yields simpler proofs of known results, as well as new results about systems where the number of components in a module is not fixed, but subject to lower and upper bounds.