Which Decision Theory Describes Life Satisfaction Best? Evidence from Annual Panel Data

We use an annual household panel to test which features of prospect theory can be supported by measures of life satisfaction. We also test whether recalled or expected life satisfaction is anchored at current life satisfaction and adjusted in the direction of the recall or expectation. Using a fixed effects estimator we find that life satisfaction contains features of both classic expected utility and prospect theory. Life satisfaction depends positively on levels of income, good health, and on employment. It also depends positively on income and employment improvements, however the reverse is true for health increases. Life satisfaction is concave in income gains and convex in income losses, and it exhibits loss aversion in income and employment status, but not in health. Moreover, we find that current levels of life satisfaction are better predictors of recalled (expected) life satisfaction than past (future) life satisfaction. The results support viewing life satisfaction as representing a mixture of the classic decision utility of expected utility theory, and the value function of prospect theory. Subjects seem to use an anchoring and adjustment heuristic when answering questions about past and expected life satisfaction

Lot sizing with piecewise concave production costs

Cataloged from PDF version of article.We study the lot-sizing problem with piecewise concave production costs and concave holding costs. This problem is a generalization of the lot-sizing problem with quantity discounts, minimum order quantities, capacities, overloading, subcontracting or a combination of these. We develop a dynamic programming algorithm to solve this problem and answer an open question in the literature: we show that the problem is polynomially solvable when the breakpoints of the production cost function are time invariant and the number of breakpoints is fixed. For the special cases with capacities and subcontracting, the time complexity of our algorithm is as good as the complexity of algorithms available in the literature. We report the results of a computational experiment where the dynamic programming is able to solve instances that are hard for a mixed-integer programming solver. We enhance the mixed-integer programming formulation with valid inequalities based on mixing sets and use a cut-and-branch algorithm to compute better bounds. We propose a state space reduction–based heuristic algorithm for large instances and show that the solutions are of good quality by comparing them with the bounds obtained from the cut-and-branch

Vesicles in solutions of hard rods

The surface free energy of ideal hard rods near curved hard surfaces is determined to second order in curvature for surfaces of general shape. In accordance with previous results for spherical and cylindrical surfaces it is found that this quantity is non-analytical when one of the principal curvatures changes signs. This prohibits writing it in the common Helfrich form. It is shown that the non-analytical terms are the same for any aspect ratio of the rods. These results are used to find the equilibrium shape of vesicles immersed in solutions of rod-like (colloidal) particles. The presence of the particles induces a change in the equilibrium shape and to a shift of the prolate-oblate transition in the vesicle phase diagram, which are calculated within the framework of the spontaneous curvature model. As a consequence of the special form of the energy contribution due to the rods these changes cannot be accounted for by a simple rescaling of the elastic constants of the vesicle as for solutions of spherical colloids or polymers.Comment: 11 pages, 7 figures, submitted to Phys. Rev.

SHOP2: An HTN Planning System

The SHOP2 planning system received one of the awards for distinguished performance in the 2002 International Planning Competition. This paper describes the features of SHOP2 which enabled it to excel in the competition, especially those aspects of SHOP2 that deal with temporal and metric planning domains

Stochastic lot sizing problem with controllable processing times

Cataloged from PDF version of article.In this study, we consider the stochastic capacitated lot sizing problem with controllable processing times where processing times can be reduced in return for extra compression cost. We assume that the compression cost function is a convex function as it may reflect increasing marginal costs of larger reductions and may be more appropriate when the resource life, energy consumption or carbon emission are taken into consideration. We consider this problem under static uncertainty strategy and α service level constraints. We first introduce a nonlinear mixed integer programming formulation of the problem, and use the recent advances in second order cone programming to strengthen it and then solve by a commercial solver. Our computational experiments show that taking the processing times as constant may lead to more costly production plans, and the value of controllable processing times becomes more evident for a stochastic environment with a limited capacity. Moreover, we observe that controllable processing times increase the solution flexibility and provide a better solution in most of the problem instances, although the largest improvements are obtained when setup costs are high and the system has medium sized capacities

Can Behavioural Economics Be Applied To Life Satisfaction?: Evidence From Annual Panel Data

We use an annual household panel to test whether a number of findings in behavioural economics can be supported by measures of life satisfaction and other variables. We test the following hypotheses: life satisfaction is increasing and concave in income gains; life satisfaction is decreasing and convex in income losses; changes in income, health, and employment are evaluated against a reference point; loss aversion applies to income, health and employment; recalled or expected life satisfaction is anchored at current life satisfaction and adjusted in the direction of the recall or expectation. Using a fixed effects estimator, we find that life satisfaction is increasing and concave in income gains, decreasing and convex in income losses, influenced by both the levels of income, health and employment, as well as their changes compared to the previous year. Moreover, we find that current levels of life satisfaction are better predictors of remembered (expected) life satisfaction than past (future) life satisfaction. The results provide support for prospect theory, anchoring and adjustment, and raise doubts about using the status quo as the correct reference point

Membranes in rod solutions: a system with spontaneously broken symmetry

We consider a dilute solution of infinitely rigid rods near a curved, perfectly repulsive surface and study the contribution of the rod depletion layer to the bending elastic constants of membranes. We find that a spontaneous curvature state can be induced by exposure of BOTH sides of the membrane to a rod solution. A similar result applies for rigid disks with a diameter equal to the rod's length. We also study the confinement of rods in spherical and cylindrical repulsive shells. This helps elucidate a recent discussion on curvature effects in confined quantum mechanical and polymer systems.Comment: 10 pages, 2 figures, 1 table; submitted to PR

Entropic Interactions in Suspensions of Semi-Flexible Rods: Short-Range Effects of Flexibility

We compute the entropic interactions between two colloidal spheres immersed in a dilute suspension of semi-flexible rods. Our model treats the semi-flexible rod as a bent rod at fixed angle, set by the rod contour and persistence lengths. The entropic forces arising from this additional rotational degree of freedom are captured quantitatively by the model, and account for observations at short range in a recent experiment. Global fits to the interaction potential data suggest the persistence length of fd-virus is about two to three times smaller than the commonly used value of $2.2 \mu {m}$.Comment: 4 pages, 5 figures, submitted to PRE rapid communication

Star p-hub center problem and star p-hub median problem with bounded path lengths

We consider two problems that arise in designing two-level star networks taking into account service quality considerations. Given a set of nodes with pairwise traffic demand and a central hub, we select p hubs and connect them to the central hub with direct links and then we connect each nonhub node to a hub. This results in a star/star network. In the first problem, called the Star p-hub Center Problem, we would like to minimize the length of the longest path in the resulting network. In the second problem, Star p-hub Median Problem with Bounded Path Lengths, the aim is to minimize the total routing cost subject to upper bound constraints on the path lengths. We propose formulations for these problems and report the outcomes of a computational study where we compare the performances of our formulations. © 2012 Elsevier Ltd. All rights reserved

Characterization of polyphenols and mineral contents in three medicinal weeds

Aims: Common weeds Rorippa palustris (L.) Besser, Euphorbia rothiana Spreng. and Schoenoplectiella articulata (L.) Lye are used for food, medicinal, green biofertilizer and biosorbent applications. In this work, their polyphenol and mineral contents have been characterized. Methodology: Samples from aforementioned three plants were manually collected in Raipur city (CG, India) and processed for the analyses. Folin-Ciocalteu and aluminum chloride were used for the spectrophotometric determination of polyphenols. The mineral contents were quantified by X-ray fluorescence. Results: The total concentration of 20 elements (viz. P, S, Cl, As, Se, K, Rb, Mg, Ca, Sr, Ba, Al, Ti, Cr, Mn, Fe, Co, Zn, Mo and Pb), total polyphenol and flavonoid contents in the leaves ranged from 46372 to 71501, from 47877 to 73791 and from 1950 to 9400 mg/kg, respectively. Remarkable concentrations of several nutrients (P, S, Cl, K, Mg, Ca and Fe) were observed. Conclusion: The biomass from medicinal weeds R. palustris, E. rothiana and S. articulata featured very high K, Ca and Fe contents. Other nutrients (polyphenols, flavonoids, P, S, Cl and Mg) were identified at moderate levels. These species may hold promise as bioindicators