Cumulative Prospect Theory for Parametric and Multiattribute Utilities

In cumulative prospect theory models, different behavior concerning gains and losses is per-mitted. For gains different decision weights are assigned than for losses, and the shape of utility can reveal loss aversion. Decision analyses concentrate on both, the capacities, which determine the decision weights, and the nature of utility. This paper focuses on linear/exponential, power and multilinear utility for decision models under uncertainty. Simple preference axioms are for-mulated for a representation by a cumulative prospect theory function. All models share the following axioms: weak ordering, continuity, monotonicity and tail independence. We first show that in their presence constant absolute (proportional) risk aversion implies linear/exponential (power) utility. Then, in the multiattribute case, considering (mutual) utility independence, it is shown that the utility function is (additive/multiplicative) multilinear.mathematical economics and econometrics ;

A Class of Methods for Evaluating Multiattribute Utilities

A state, for instance a health state, is characterized by a number of attributes to each of which a level is assigned. A specific collection of numerical values, for instance utilities, for all possible states is called a situation. The main purpose of the paper is to develop a class of methods that assign, for a given situation, a numerical value to each possible level of each attribute, intended to measure the contribution of each such level to reaching the perfect state, in which each attribute has maximal level. The paper focuses on methods that share four properties: distribution, zero contribution, homogeneity, and the transfer property. All these methods have the propertyof marginalism: they measure the effect of lowering, ceteris paribus, a certain level by one. Within the class of methods so obtained, special attention is given to the so called egalitarian valuation, which treats lower and higher levels equally.Economics ;

Phenomenology of hydromagnetic turbulence in a uniformly expanding medium

A simple phenomenology is developed for the decay and transport of turbulence in a constant-speed, uniformly expanding medium. The fluctuations are assumed to be locally incompressible, and either of the hydrodynamic or non-Alfvénic magnetohydrodynamic (MHD) type. In order to represent local effects of nonlinearities, a simple model of the Kaármá-Dryden type for locally homogeneous turbulent decay is adopted. A detailed discussion of the parameters of this familiar one-point hydrodynamic closure is given, which has been shown recently to be applicable to non-Alfvénic MHD as well. The effects of the large-scale flow and expansion are incorporated using a two-scale approach, in which assumptions of particular turbulence symmetries provide simplifications. The derived model is tractable and provides a basis for understanding turbulence in the outer heliosphere, as well as in other astrophysical applications

Turbulence, spatial transport, and heating of the solar wind

A phenomenological theory describes radial evolution of plasma turbulence in the solar wind from 1 to 50 astronomical units. The theory includes a simple closure for local anisotropic magnetohydrodynamic turbulence, spatial transport, and driving by large-scale shear and pickup ions. Results compare well to plasma and magnetic field data from the Voyager 2 spacecraft, providing a basis for a concise, tractable description of turbulent energy transport in a variety of astrophysical plasmas

Coronal heating by magnetohydrodynamic turbulence driven by reflected low-frequency waves

A candidate mechanism for the heating of the solar corona in open field line regions is described. The interaction of Alfvén waves, generated in the photosphere or chromosphere, with their reflections and the subsequent driving of quasi-two-dimensional MHD turbulence is considered. A nonlinear cascade drives fluctuations toward short wavelengths which are transverse to the mean field, thereby heating at rates insensitive to restrictive Alfvén timescales. A phenomenology is presented, providing estimates of achievable heating efficiency that are most favorable