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1.
《Mathematical and Computer Modelling》2002,35(1-2):119-128
Egress complexity is concerned with the summative uncertainty experienced by a naive occupant of a building when faced with a challenge to evacuate without the assistance of signage. This paper takes the present model of egress complexity and recasts its basic initiative in terms of elementary order theory. Arguments are presented to demonstrate
- •the existence of distinct maximum and minimum exit complexities for a given number of compartments,
- •the monotonic nature of complexity and
- •the relationship of a given floorplan complexity to the corresponding measures of its homomorphic images
2.
3.
《Statistics & probability letters》1987,5(2):87-93
The Brownian path {ω(s); 0 ⩽ s ⩽ t} is dissected and then reassembled in such a way that
- (i) the last visit γt at the origin, as well as the fragment {ω(s); γt ⩽ s ⩽ t}, are left invariant;
- (ii) on [0, γt], local time becomes maximum-to-date and occupation time of|R+ becomes location of maximum; and
- (iii) the resulting process is again Brownian.
4.
《Annals of Pure and Applied Logic》1999,96(1-3):89-105
We consider the common-knowledge paradox raised by Halpern and Moses: common knowledge is necessary for agreement and coordination, but common knowledge is unattainable in the real world because of temporal imprecision. We discuss two solutions to this paradox:
- 1.(1) modeling the world with a coarser granularity, and
- 2.(2) relaxing the requirements for coordination.
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6.
《Applied Mathematical Modelling》2002,26(2):203-221
The performance of an iron-bath reactor has been studied using a comprehensive numerical model that combines a computational fluid dynamics approach for the gas phase and a heat and mass balance model for the bath. The model calculates:
- •coal, ore, flux and oxygen consumption;
- •post-combustion ratio (PCR);
- •heat-transfer efficiency (HTE);
- •off-gas temperature and composition;
- •heat transfer and chemical reactions between gas and iron and slag droplets; and
- •heat transfer between gas and bath, refractories and lance.
7.
《Historia Mathematica》2002,29(2):193-198
Analysis of the errors in two Old Babylonian “algebraic” problems shows
- •that the computations were performed on a device where additive contributions were no longer identifiable once they had entered the computation;
- •that this device must have been some kind of counting board or abacus where numbers were represented as collections of calculi;
- •that units and tens were represented in distinct ways, perhaps by means of different calculi.
- •Additive Beiträge waren nach ihrer Eintragung in die Rechnung nicht länger identifizierbar.
- •Das Gerät war eine Art Rechenbrett, auf welchem Zahlen als Haufen von Rechensteinen erschienen.
- •Einer und Zehner wurden in verschiedener Weise, evtl. mittels verschiedener Rechensteine repräsentiert.
8.
《European Journal of Operational Research》2002,139(2):206-219
In some applications a minimum cost transportation model arises where supplies are fixed while demands may simultaneously vary. In this paper we analyse the structure of such a model and propose several techniques to describe its behaviour. Our approach is founded on the concept of optimal region, i.e., the subset of demand vectors where a given basic tree is optimal. The proposed algorithm consists in different pivoting strategies designed to:
- 1.build up a minimal list of basic trees such that the associated optimal regions cover the set of feasible demand vectors;
- 2.analyse the effects of either opening a new supplier or closing an existing one;
- 3.suitably treat the dual degenerate case by building up a minimal representation of every maximal region where the optimal value is linear in the demand vector.
9.
《Mathematical and Computer Modelling》2000,31(10-12):157-163
An auto-sleep system is defined by the following two properties:
- 1.(i) a call for the system occurs randomly and intermittently
- 2.(ii) the system automatically goes to sleep if there occurs no call during a prespecified time T.
- 1.(a) sleep
- 2.(b) warm-up
- 3.(c) nonusage
- 4.(d) usage.
10.
《European Journal of Operational Research》1986,27(1):91-94
In the construction industry, places, capacities and levels of demand in basic spare parts are changing in relatively short periods of time. This creates an optimization problem of the following form.We are given the following:o
- (i)The location and the level of demand for each basic spare part in each work site for a specific time period.
- (ii)The places and the levels of demand can be altered.
- (iii)There are more than one supplier of each part geografically distributed.
- (iv)The number of basic equipment spare parts.
- (v)The transportation cost per load of spare parts.
- (vi)The purchasing and functioning cost of the various air houses used as warehouses of spare parts.
11.
《Comptes Rendus de l'Academie des Sciences Series IIA Earth and Planetary Science》1997,324(6):659-663
We prove the following theorems:
- 1)Any surgery of index one on u tight contact manifold (of dimension three) gives rise to a manifold which carries a natural tight contact structure.
- 2)In a tight contact manifold, any two isotopic spheres which carry the same characteristic foliation are isotopic through a contact isolopy.
- 3)In a tight contact manifold, any two isotopic spheres have isomorphic complements.
12.
13.
《Applied Mathematics Letters》2003,16(5):657-662
The paper studies equation (1.1) in two cases:
- •(i)p ≡ 0,
- •(ii)p ≠ 0.
14.
《Journal de Mathématiques Pures et Appliquées》1999,78(2):121-157
This paper is devoted to the characterization of external electrostatic potentials for which the Vlasov-Poisson-Fokker-Planck system satisfies one of the following properties:
- (i) the system admits stationary solutions,
- (ii) any solution to the evolution problem converges to a stationary solution, or, equivalently, no mass vanishes for large times,
- (iii) the free energy is bounded from below, We give conditions under which these different notions of confinement are equivalent.
15.
Bidirected graphs generalize directed and undirected graphs in that edges are oriented locally at every node. The natural notion of the degree of a node that takes into account (local) orientations is that of net-degree. In this paper, we extend the following four topics from (un)directed graphs to bidirected graphs:
- –Erdős–Gallai-type results: characterization of net-degree sequences,
- –Havel–Hakimi-type results: complete sets of degree-preserving operations,
- –Extremal degree sequences: characterization of uniquely realizable sequences, and
- –Enumerative aspects: counting formulas for net-degree sequences.
16.
《Mathematical and Computer Modelling》2004,39(11-12):1213-1220
This work deals with the modelling of a three-link manipulator mounted on a plane with a time-dependent inclination. Two cases are considered.
- (i)The plane is part of a rigid body.
- (ii)The plane is in a moored ship.
17.
《Mathematical and Computer Modelling》1998,27(9-11):27-49
This paper formulates the Dynamic Traffic Routing (DTR) problem as a real-time feedback control problem. Three different forms of the formulation are presented:
- 1.(1) distributed parameter system form derived from the conservation law;
- 2.(2) space discretized continuous lumped parameter form;
- 3.(3) space and time discretized lumped parameter form.
18.
《Applied Mathematics Letters》2002,15(2):153-157
The authors use their recently proved integral inequality to obtain bounds for the covariance of two random variables
- 1.in a general setup and
- 2.for a class of special joint distributions.
19.
《European Journal of Operational Research》2006,174(2):1260-1280
In this paper, we set up a House of Profit Model, an approach of maximizing profit of a food retailing chain by targeting and promoting valuable customers. Our model combines
- •segmentation analysis of households using Loyalty Card and Scanner Data,
- •price and promotion elasticity analysis,
- •simulation of effects of pricing and promotion,
- •price and promotion optimization to maximize profit.
20.
If ξ∈ (0,1) and A=an, n?? is a sequence of real numbers define Sn(ξ,A)∶=Σ{ak∶:k=[nξ]+1 to n}, n??, where [x] is the greatest integer less than or equal to x. In the theory of regularly varying sequences the problem arose to conclude from the convergence of the sequence Sn (ξ,A), n??, for all ξ in an appropriate set K of real numbers, that the sequence an, n??, converges to zero. It was shown that such a conclusion is possible if K={ξ,1?ξ} with ξ∈ (0,1) irrational. Then the following three questions were posed and will be answered in this paper:
- does the convergence of Sn (ξ,A), n??, for a single irrational number ξ imply an→0.
- does the convergence of Sn(ξ,A), n??, for finitely many rational numbers ξ∈ (0, 1) imply an→0.
- does the convergence of Sn (ξ,A), n??, for all rational numbers ξ∈ (0,1) imply an→0?