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《European Journal of Operational Research》1988,35(3):350-364
A model for regional solid waste management as a network flow problem is described, and a special purpose algorithm is developed. The model is applied to waste management and facility siting decisions in the Munich Metropolitan Area in the Federal Republic of Germany. 相似文献
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Patrick Jungkunz Christian J. Darken 《Computational & Mathematical Organization Theory》2011,17(3):229-250
Models of eye movements of an observer searching for human targets are helpful in developing accurate models of target acquisition
times and false positive detections. We develop a new model describing the distribution of gaze positions for an observer
which includes both bottom-up (salience) and top-down (task dependent) factors. We validate the combined model against a bottom-up
model from the literature and against the bottom up and top down parts alone using human performance data on stationary targets.
The new model is shown to be significantly better. The new model requires a large amount of data about the terrain and the
target that is obtained directly from the 3D simulation through an automated process. 相似文献
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The objective of this contribution is to study computational aspects of modeling thermo-mechanical solids containing mechanically energetic, geometrically non-coherent Kapitza interfaces under cyclic loading. The interface is termed energetic in the sense that it possesses its own energy, entropy, constitutive relations and dissipation. To date, classical thermo-mechanical cohesive zone models do not account for elastic interfaces. Therefore we propose a novel interface model that couples the classical cohesive zone formulation to the interface elasticity theory under the Kapitza assumption within a thermo-mechanical framework. In other words, such an interface model allows for discontinuities in geometry, temperature and normal stress fields, while not permitting a jump in the normal heat flux across the interface. The equations governing a fully non-linear transient problem are given. In particular, a comparison is made between the results of the classical thermo-mechanical cohesive zone model and our novel (cohesive + energetic Kapitza) interface formulation. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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《Journal of computational science》2013,4(3):135-143
This paper presents a computational model to organize multi-agent E-commerce negotiations with adaptive negotiation behaviors aiming at enhancing the negotiation flexibilities of software agents. Firstly, the computational E-commerce negotiation model covering negotiation protocol, negotiation issues and negotiation strategies is specified to assist agents’ computing functions. Then, a three-staged adaptive negotiation behavior configuration mechanism is proposed to tackle the negotiation dynamics. In the pre-negotiation stage, agents’ negotiation behaviors are deployed by the case-based strategy assignment mechanism; in the on-going negotiation stage, opponents’ negotiation behaviors are tracked through the neural network learning model; in the post-negotiation stage, opponents’ concession functions are recorded using the time series measure. Finally, the computational negotiation model is tested through hypothetical negotiation cases. The outcomes show that the adaptive negotiation behavior configuration mechanism can benefit an agent to win more in the E-commerce negotiation. 相似文献
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Gianluca Martelloni Franco Bagnoli Emanuele Massaro 《Communications in Nonlinear Science & Numerical Simulation》2013,18(9):2479-2492
The aim of this paper is to propose a 2D computational algorithm for modeling the triggering and propagation of shallow landslides caused by rainfall. We used a molecular dynamics (MD) approach, similar to the discrete element method (DEM), that is suitable to model granular material and to observe the trajectory of a single particle, so to possibly identify its dynamical properties. We consider that the triggering of shallow landslides is caused by the decrease of the static friction along the sliding surface due to water infiltration by rainfall. Thence the triggering is caused by the two following conditions: (a) a threshold speed of the particles and (b) a condition on the static friction, between the particles and the slope surface, based on the Mohr–Coulomb failure criterion. The latter static condition is used in the geotechnical model to estimate the possibility of landslide triggering. The interaction force between particles is modeled, in the absence of experimental data, by means of a potential similar to the Lennard-Jones one. The viscosity is also introduced in the model and for a large range of values of the model’s parameters, we observe a characteristic velocity pattern, with acceleration increments, typical of real landslides. The results of simulations are quite promising: the energy and time triggering distribution of local avalanches show a power law distribution, analogous to the observed Gutenberg–Richter and Omori power law distributions for earthquakes. Finally, it is possible to apply the method of the inverse surface displacement velocity [4] for predicting the failure time. 相似文献
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Disproportionate collapse analysis aims to assure that frames, a common structural system of buildings, can survive unforeseen
local events and a central modeling tool of such abnormal deterioration is the concept of column loss. This paper formulates
an appropriate computational model on the basis of mathematical optimization, using the collapse load analysis problem of
steel frames with pre-existing damage. A respective collapse load robustness measure is proposed. The model has the ability
to consider both full and partial column/node removals. It renders to be a linear programming model, if the US steel design
regulations are used. A practical example is presented and several aspects are discussed. 相似文献
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In transformation induced plasticity (TRIP) steel a diffusionless austenitic-martensitic phase transformation induced by plastic deformation can be observed, resulting in excellent macroscopic properties. In particular low-alloyed TRIP steels, which can be obtained at lower production costs than high-alloyed TRIP steel, combine this mechanism with a heterogeneous arrangement of different phases at the microscale, namely ferrite, bainite, and retained austenite. The macroscopic behavior is governed by a complex interaction of the phases at the micro-level and the inelastic phase transformation from retained austenite to martensite. A reliable model for low-alloyed TRIP steel should therefore account for these microstructural processes to achieve an accurate macroscopic prediction. To enable this, we focus on a multiscale method often referred to as FE2 approach, see [6]. In order to obtain a reasonable representative volume element, a three-dimensional statistically similar representative volume element (SSRVE) [1] can be used. Thereby, also computational costs associated with FE2 calculations can be significantly reduced at a comparable prediction quality. The material model used here to capture the above mentioned microstructural phase transformation is based on [3] which was proposed for high alloyed TRIP steels, see also e.g. [8]. Computations based on the proposed two-scale approach are presented here for a three dimensional boundary value problem to show the evolution of phase transformation at the microscale and its effects on the macroscopic properties. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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A simplified model of a marine mussel is proposed. We model the digestive system as a cellular analogue, physically partitioned into a lysosome and endosome, with the flow of particulate carbon to represent energy. The parameters in the rate equations that govern the interactions between compartments are assumed to be a simple linear form but are consistent with experiment and observation. The model is tested first by using continuous feeding and then by using a periodic feeding representative of tidal input. The responses in both cases produce interesting results compatible with observations of the biology of the animal. We define a “health function” which indicates whether or not the animal survives. It is found that survival is critically dependent on lysosomal efficiency. 相似文献
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A one‐dimensional computational model for hyperelastic string structures with Coulomb friction
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In this paper, we consider a new model for the simulation of textiles with frictional contact between fibers and no bending resistance. In the model, one‐dimensional hyperelasticity and the Capstan equation are combined, and its connection with conventional hyperelasticity and Coulomb friction models is shown. Then, the model is formulated as a problem with the rate‐independent dissipation, and we prove that the problem possesses proper convexity and continuity properties. The article concludes with a numerical algorithm and provides numerical experiments along with a comparison of the results with a real measurement. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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The paper considers a model of a bonus-malus system with a variable trend in the case of a three-parameter gamma distribution. The parameters of the distribution and the value of the trend are selected based on statistical data. The indexes of the bonus-malus system are obtained. 相似文献
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Large scale and multidisciplinary engineering projects (e.g., design of a hospital building) are often complex. They usually involve many interdependent activities and require intensive coordination among actors (i.e., designers) to deal with activity interdependencies. To make such projects more effective and efficient, one needs to understand how coordination requirements are generated and what coordination mechanisms should be applied for given project situations. Our research on the Virtual Design Team (VDT) attempts to develop a computational model of project organizations to analyze how activity interdependencies raise coordination needs and how organization design and communication tools change team coordination capacity and project performance. The VDT model is built based on contingency theory (Galbraith, 1977) and our observations about collaborative and multidisciplinary work in large, complex projects. VDT explicitly models actors, activities, communication tools and organizations. Based on our extended information-processing view of organizations, VDT simulates the actions of, and interactions among actors as processes of attention allocation, capacity allocation, and communication. VDT evaluates organization performance by measuring emergent project duration, direct cost, and coordination quality. The VDT model has been tested internally, and evaluated externally through case-studies. We found three way qualitative consistency among predictions of the simulation model, of organization theory, and of experienced project managers. In this paper, we present the VDT model in detail and discuss some general issues involved in computational organization modeling, including level of abstraction of tasks and actors' reasoning, and model validation. 相似文献
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A computational multiscale contact mechanics model is presented which describes the interaction between deformable solids based on the interaction of individual atoms or molecules. The contact model is formulated in the framework of large deformation continuum mechanics and combines the approaches of molecular modelling [1] and continuum contact mechanics [2]. In the following a brief overview of the contact model is given. Further details can be found in [3], [4] and [5]. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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M. J. Jacobson Jr. Á . Pinté r P. G. Walsh. 《Mathematics of Computation》2003,72(244):2099-2110
We present a computational approach for finding all integral solutions of the equation for even values of . By reducing this problem to that of finding integral solutions of a certain class of quartic equations closely related to the Pell equations, we are able to apply the powerful computational machinery related to quadratic number fields. Using our approach, we determine all integral solutions for assuming the Generalized Riemann Hypothesis, and for unconditionally.
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We give a criterion for the Kac conjecture asserting that the free term of the polynomial counting the absolutely indecomposable representations of a quiver over a finite field of given dimension coincides with the corresponding root multiplicity of the associated Kac–Moody algebra. Our criterion suits very well for computer tests. 相似文献
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The article describes an approach to the design of a programming support system for the construction of modular computational
programs. The system automates generation of programs for simulation of multiparameter mathematical models.
Translated from Chislennye Metody v Matematicheskoi Fizike, Published by Moscow University, Moscow, 1996, pp. 52–57. 相似文献
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We consider the problems of semi-graphoid inference and of independence implication from a set of conditional-independence statements. Based on ideas from R. Hemmecke et al. [Combin. Probab. Comput., 2008, 17: 239–257], we present algebraic-geometry characterizations of these two problems, and propose two corresponding algorithms. These algorithms can be realized with any computer algebra system when the number of variables is small. 相似文献