135 research outputs found
Application of Decision Analysis to Pollution Control: The Rhine River Study
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
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
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
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
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
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
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
Recommended from our members
ACTRIS ACSM intercomparison - Part 2: Intercomparison of ME-2 organic source apportionment results from 15 individual, co-located aerosol mass spectrometers
Chemically resolved atmospheric aerosol data sets from the largest intercomparison of the Aerodyne aerosol chemical speciation monitors (ACSMs) performed to date were collected at the French atmospheric supersite SIRTA. In total 13 quadrupole ACSMs (Q-ACSM) from the European ACTRIS ACSM network, one time-of-flight ACSM (ToF-ACSM), and one high-resolution ToF aerosol mass spectrometer (AMS) were operated in parallel for about 3 weeks in November and December~2013. Part 1 of this study reports on the accuracy and precision of the instruments for all the measured species. In this work we report on the intercomparison of organic components and the results from factor analysis source apportionment by positive matrix factorisation (PMF) utilising the multilinear engine 2 (ME-2). Except for the organic contribution of mass-to-charge ratio m/z 44 to the total organics (f44), which varied by factors between 0.6 and 1.3 compared to the mean, the peaks in the organic mass spectra were similar among instruments. The m/z 44 differences in the spectra resulted in a variable f44 in the source profiles extracted by ME-2, but had only a minor influence on the extracted mass contributions of the sources. The presented source apportionment yielded four factors for all 15 instruments: hydrocarbon-like organic aerosol (HOA), cooking-related organic aerosol (COA), biomass burning-related organic aerosol (BBOA) and secondary oxygenated organic aerosol (OOA). ME-2 boundary conditions (profile constraints) were optimised individually by means of correlation to external data in order to achieve equivalent / comparable solutions for all ACSM instruments and the results are discussed together with the investigation of the influence of alternative anchors (reference profiles). A comparison of the ME-2 source apportionment output of all 15 instruments resulted in relative standard deviations (SD) from the mean between 13.7 and 22.7 % of the source's average mass contribution depending on the factors (HOA: 14.3 ± 2.2 %, COA: 15.0 ± 3.4 %, OOA: 41.5 ± 5.7 %, BBOA: 29.3 ± 5.0 %). Factors which tend to be subject to minor factor mixing (in this case COA) have higher relative uncertainties than factors which are recognised more readily like the OOA. Averaged over all factors and instruments the relative first SD from the mean of a source extracted with ME-2 was 17.2 %
Recommended from our members
In situ, satellite measurement and model evidence on the dominant regional contribution to fine particulate matter levels in the Paris megacity
A detailed characterization of air quality in the megacity of Paris (France) during two 1-month intensive campaigns and from additional 1-year observations revealed that about 70 % of the urban background fine particulate matter (PM) is transported on average into the megacity from upwind regions. This dominant influence of regional sources was confirmed by in situ measurements during short intensive and longer-term campaigns, aerosol optical depth (AOD) measurements from ENVISAT, and modeling results from PMCAMx and CHIMERE chemistry transport models. While advection of sulfate is well documented for other megacities, there was surprisingly high contribution from long-range transport for both nitrate and organic aerosol. The origin of organic PM was investigated by comprehensive analysis of aerosol mass spectrometer (AMS), radiocarbon and tracer measurements during two intensive campaigns. Primary fossil fuel combustion emissions constituted less than 20 % in winter and 40 % in summer of carbonaceous fine PM, unexpectedly small for a megacity. Cooking activities and, during winter, residential wood burning are the major primary organic PM sources. This analysis suggests that the major part of secondary organic aerosol is of modern origin, i.e., from biogenic precursors and from wood burning. Black carbon concentrations are on the lower end of values encountered in megacities worldwide, but still represent an issue for air quality. These comparatively low air pollution levels are due to a combination of low emissions per inhabitant, flat terrain, and a meteorology that is in general not conducive to local pollution build-up. This revised picture of a megacity only being partially responsible for its own average and peak PM levels has important implications for air pollution regulation policies
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . 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
- …