Search results for "Simulation Model"
showing 10 items of 68 documents
A Note on Qualitative Input-Output Analysis
1995
International audience; The paper discusses qualitative input—output methods. It is shown that information is lost. Because the binaiy relationship constructed by qualitative methods is not transitive, the model lacks economic consistency. Qualitative methods are tending to become more sophisticated, but some problems of economic interpretation are raised.
Normalizing biproportional methods
2002
International audience; Biproportional methods are used to update matrices: the projection of a matrix Z to give it the column and row sums of another matrix is R Z S, where R and S are diagonal and secure the constraints of the problem (R and S have no signification at all because they are not identified). However, normalizing R or S generates important mathematical difficulties: it amounts to put constraints on Lagrange multipliers, non negativity (and so the existence of the solution) is not guaranteed at equilibrium or along the path to equilibrium.
Relevance of Tool Life Testing for Tool Replacement Strategies
1986
Several analytical and simulation models have been proposed in order to select the optimal tool replacement strategies both in single and multi-tool machining operations. All of these models, however, assume as known the probability density function that describes the stochastic behaviour of tool life. The costly efforts required in order to achieve an accurate estimate of the p.d.f. limits the use in the shop practice of the above models.
A simulation/optimization model for selecting infrastructure alternatives in complex water resource systems
2010
The paper introduces a simulation/optimization procedure for the assessment and the selection of infrastructure alternatives in a complex water resources system, i.e. in a multisource (reservoirs) multipurpose bulk water supply scheme. An infrastucture alternative is here a vector X of n decision variables describing the candidate expansions/new plants/water transfers etc. Each parameter may take on a discrete number of values, with its own investment cost attached. The procedure uses genetic algorithms for the search of the optimal vector X through operators mimicking the mechanisms of natural selection. For each X, the value of the objective function (O.F.) is assessed via a simulation mo…
An ACE Wholesale Electricity Market Framework with Bilateral Trading
2011
In this paper, an agent-based simulation model for a hybrid power market structure is presented. A bilateral transaction mechanism is combined with a uniform-pricing auction settlement in order to isolate the impact of medium-term bilateral contracts on market power and spot prices in a competitive wholesale market setting. First we describe the negotiation method for bilateral trading of energy and then introduce a new approach for bidding in the DA market based on the load duration curve. We find that, despite the conventional concerns, the foreclosure effect produced by the bilateral agreement between a generation and a retail business will not necessarily lead to higher prices, and will…
Editorial: Calculation of Passenger Car Equivalents at Roundabouts
2021
Editorial on the Research Topic: Calculation of Passenger Car Equivalents at Roundabouts About this Research Topic: Calculation of Passenger Car Equivalents (PCEs) for heavy vehicles represents the starting point for the operational analysis of road facilities and other traffic management applications. PCEs are used to consider the presence of heavy vehicles in the traffic stream and are expressed as multiples of the effect of an average passenger car. Moreover, the highly curvilinear nature of the roundabout design, both in urban and rural environment, has significant effects on the paths that heavy vehicles would travel; as a consequence, the interaction between the physical and performan…
Complex Adaptive Systems and Agent-Based Modelling
2015
In a labour–education market system, there are many individuals and firms with adaptive behaviour. As we have seen in the previous chapter, networks are prevalent in LEMS and play an important role in many decisions of its actors. Thus, LEMS can be analysed as a complex adaptive system (CAS). Agent-based modelling (ABM) is typically used for such purposes, and the next chapter will dig into details of various ways of applying ABM in modelling LEMS. To be ready for it, we first have to understand the motivation behind and the details of this method. This is what will be discussed here.
Is the Ghosh model interesting?
2009
International audience; The overall value of the Ghosh model is appraised. Its treatment of quantities and prices is scrutinized by examining the variant with data in quantities and prices, and the variant with data in value and price indexes. The methodology involves returning to the accounting equations and shows that: (i) the Ghosh model offers solutions of limited interest, being incapable of providing prices or price indexes separately from quantities; (ii) what is taken to be the equation of Ghosh's value model is actually that of Ghosh's physical model; (iii) the Ghosh model may serve for cost-push exercises, but the dual of the Leontief model performs the same task in a much simpler…
A heuristic for problem formalization in agent based simulation studies
2015
Agent Based Modeling and Simulation (ABMS) is considered an effective approach for conducting simulation studies in many fields. In order to develop high quality simulation models, methodological approaches are demanded. In such direction we are moving by proposing a heuristic for the formalization of agent based simulation problems. The proposed heuristic is based on some guidelines developed for identifying the main elements of the problem domain description by analysing verbs and their common taxonomy in grammar.
Biproportional methods of structural change analysis: A typological survey
2004
International audience; Analysts often are interested in learning how much an exchange system has changed over time or how two different exchange systems differ. Identifying structural difference in exchange matrices can be performed using either 'directed' or 'undirected' methods. Directed methods are based on the computation and comparison of column- or row-normalizations of the matrices. The choice of row or column for the normalization implies a specific direction of the exchanges, so that the column-wise normalized results should not be compared to the row-wise normalized results. In this category fall the simple comparison of coefficient matrices and the causative method. Undirected m…