4,392 research outputs found
Between the Gift and the Market: The Economy of Regard..
'The great transformation' from customary exchange to impersonal markets is incomplete. Reciprocal exchange pervades modern societies. it takes the form of 'gifts,' reciprocated without certainty. Reciprocity is driven by the pursuit of 'regard'. Money is avoided in regard exchanges, because it is impersonal. Instead, regard signals are embodied in goods, in services, or in time (attention). The personalization of gifts authenticates the signal. Reciprocal exchange persists in family formation, in intergenerational transfers, in labor markets, in agriculture, the professions, in marketing, entrepreneurship, and also in corruption and crime. Reciprocal exchange is constrained by the time and psychic energy, but is likely to persist as a preferred source of regard.
Two-sided reflected Markov-modulated Brownian motion with applications to fluid queues and dividend payouts
In this paper we study a reflected Markov-modulated Brownian motion with a
two sided reflection in which the drift, diffusion coefficient and the two
boundaries are (jointly) modulated by a finite state space irreducible
continuous time Markov chain. The goal is to compute the stationary
distribution of this Markov process, which in addition to the complication of
having a stochastic boundary can also include jumps at state change epochs of
the underlying Markov chain because of the boundary changes. We give the
general theory and then specialize to the case where the underlying Markov
chain has two states. Moreover, motivated by an application of optimal dividend
strategies, we consider the case where the lower barrier is zero and the upper
barrier is subject to control. In this case we generalized earlier results from
the case of a reflected Brownian motion to the Markov modulated case.Comment: 22 pages, 1 figur
A new formula for some linear stochastic equations with applications
We give a representation of the solution for a stochastic linear equation of
the form where is a
c\'adl\'ag semimartingale and is a c\'adl\'ag adapted process with bounded
variation on finite intervals. As an application we study the case where
and are nondecreasing, jointly have stationary increments and the jumps of
are bounded by 1. Special cases of this process are shot-noise processes,
growth collapse (additive increase, multiplicative decrease) processes and
clearing processes. When and are, in addition, independent L\'evy
processes, the resulting is called a generalized Ornstein-Uhlenbeck
process.Comment: Published in at http://dx.doi.org/10.1214/09-AAP637 the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Useful martingales for stochastic storage processes with L\'{e}vy-type input
In this paper we generalize the martingale of Kella and Whitt to the setting
of L\'{e}vy-type processes and show that the (local) martingales obtained are
in fact square integrable martingales which upon dividing by the time index
converge to zero a.s. and in . The reflected L\'{e}vy-type process is
considered as an example.Comment: 15 pages. arXiv admin note: substantial text overlap with
arXiv:1112.475
Modelling of Supercapacitors: Factors Influencing Performance
The utilizable capacitance of Electrochemical Double Layer Capacitors (EDLCs) is a function of the frequency at which they are operated and this is strongly dependent on the construction and physical parameters of the device. We simulate the dynamic behavior of an EDLC using a spatially resolved model based on the porous electrode theory. The model of Verbrugge and Liu (J. Electrochem. Soc. 152, D79 (2005)) was extended with a dimension describing the transport into the carbon particle pores. Our results show a large influence of the electrode thickness (Le), separator thickness (Ls) and electrolyte conductivity (κ) on the performance of EDLCs. In agreement with experimental data, the time constant was an increasing function of Le and Ls and a decreasing function of κ. The main limitation was found to be on the scale of the whole cell, while transport into the particles became a limiting factor only if the particle size was unrealistically large. The results were generalized into a simplified relation allowing for a quick evaluation of performance for the design of new devices. This work provides an insight into the performance limitation of EDLCs and identifies the critical parameters to consider for both systems engineers and material scientists
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