135 research outputs found

    Application of Decision Analysis to Pollution Control: The Rhine River Study

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    As water resources are more intensively used and as water quality deteriorates there is an increasing need for improved decision making processes to manage them. Since both economic and social criteria, and several interest groups with often conflicting preferences are involved, multi-dimensional utility functions are employed in the analysis. This paper presents a preliminary application of a model employing several forms of utility functions to the control of water quality on the Rhine River in which optimal treatment levels are found by simultaneously solving a system of non-linear equations. The applicability of additive and multiplicative forms of utility objective functions is studied, and the relation of this model to real world decision making is described

    A Decision Analytic Approach to River Basin Pollution Control

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    Often several cities discharge their sewage into a single river. Such cities are concerned with the water quality of the river as it flows past them and with the costs associated with treatment. A utility function for each city describes the trade-offs. Preferences often conflict: the cities downstream wish that those upstream would treat their waste more intensively. Ambient conditions in the river are uncertain but can be expressed in terms of probability densities. The paper describes approaches to finding admissible solutions to the multi-interest-group water resource problem using Paretian analysis and optimal control theory. An example is solved, and extensions are discussed

    Balancing Apples and Oranges: Methodologies for Facility Siting Decisions

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    Evaluating alternative sites for major constructed facilities requires comparing impacts of different levels and different types to establish desirable yet feasible balances. Currently employed and proposed, methodologies for evaluating the desirability of sets of impacts generated by large facilities are compared, and the theoretical assumptions implicit in each are discussed. In aggregate, the three sets of methodologies considered are Cost-Benefit Analysis and its various modifications, matrix or tableau methods of several sorts, and, preference theory (of which utility is a special case). Primary attention is given to the structure of objective functions defined over impacts

    A Framework for Evaluation of Public Policy on the Use of Agricultural Chemicals

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    Although the contribution of chemicals to increased agricultural production is generally recognized, the potentially hazardous side-effects of some of these chemicals are causing a reassessment of their use. For rational public-policy choices to be made, simultaneous account needs to be taken of the contribution of chemicals to agricultural productivity and their potential hazards to various forms of life. The purpose of this paper is to suggest utility analysis as a framework for structuring a systematic decision-making process to determine public policy in this area

    Extrapolating Trending Geological Bodies

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    An attempt is made to structure the heuristic process of extrapolating trending geologic bodies in the analytic framework of Bayesian inference. The approach models spatial properties of trending bodies rather than geological processes, and includes components of uncertainty arising out of trend model selection. Inclusion of several components of uncertainty leads to rapid dispersion of the probability density of predicted location away from the region of observations, in conformity with the intuitive notion of valid distances of prediction. The philosophical foundations of exploration and the role of probabilistic predictions in decisionmaking are briefly discussed

    A Systems Analysis Approach to Nuclear Facility Siting

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    In recent years there has been a growing tendency in science to conduct multi-disciplinary studies of large-scale systems. These studies include the entire spectrum of economic, technological, environmental and societal factors which characterize the complex problems of advanced industrialized societies. One of the more promising ways of addressing these problems is the broad research strategy of applied systems analysis. Basically this is a rational approach to problem-solving which attempts to identify and model interactions between the systems under study and all other systems. This results in a thorough understanding of the system being studied which may then serve as an aid in decision-making. This paper attempts to demonstrate an application of the techniques of systems analysis, which have been successful in solving a variety of problems, to the question of nuclear facility siting

    Variational state based on the Bethe ansatz solution and a correlated singlet liquid state in the one-dimensional t-J model

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    The one-dimensional t-J model is investigated by the variational Monte Carlo method. A variational wave function based on the Bethe ansatz solution is newly proposed, where the spin-charge separation is realized, and a long-range correlation factor of Jastrow-type is included. In most regions of the phase diagram, this wave function provides an excellent description of the ground-state properties characterized as a Tomonaga-Luttinger liquid; Both of the amplitude and exponent of correlation functions are correctly reproduced. For the spin-gap phase, another trial state of correlated singlet pairs with a Jastrow factor is introduced. This wave function shows generalized Luther-Emery liquid behavior, exhibiting enhanced superconducting correlations and exponential decay of the spin correlation function. Using these two variational wave functions, the whole phase diagram is determined. In addition, relations between the correlation exponent and variational parameters in the trial functions are derived.Comment: REVTeX 3.0, 27 pages. 7 figures available upon request ([email protected]). To be published in Phys. Rev. B 5

    Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

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    The inclusive transverse momentum (pTp_{\rm T}) distributions of primary charged particles are measured in the pseudo-rapidity range η<0.8|\eta|<0.8 as a function of event centrality in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}}=2.76 TeV with ALICE at the LHC. The data are presented in the pTp_{\rm T} range 0.15<pT<500.15<p_{\rm T}<50 GeV/cc for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor RAAR_{\rm{AA}} using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pTp_{\rm T} particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with RAA0.13R_{\rm{AA}}\approx0.13 at pT=6p_{\rm T}=6-7 GeV/cc. Above pT=7p_{\rm T}=7 GeV/cc, there is a significant rise in the nuclear modification factor, which reaches RAA0.4R_{\rm{AA}} \approx0.4 for pT>30p_{\rm T}>30 GeV/cc. In peripheral collisions (70-80%), the suppression is weaker with RAA0.7R_{\rm{AA}} \approx 0.7 almost independently of pTp_{\rm T}. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284
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