92,256 research outputs found
Race and Policing: An Agenda for Action
This paper is organized into two parts -- Strategic Voice and Tactical Agency. Strategic Voice argues that problems of race in policing cannot be resolved by the police alone. Other people must help by understanding and ameliorating the social conditions that cause race to be associated with crime and hence become a dilemma for American policing. Rather than accepting these conditions as givens, police leaders with their powerful collective voice should actively call attention to what needs to be changed. Tactical Agency outlines what the police can do on their own initiative to deal with the operational dilemmas of race -- in the communities they serve and in their own organizations
Utility based pricing and hedging of jump diffusion processes with a view to applications
We discuss utility based pricing and hedging of jump diffusion processes with
emphasis on the practical applicability of the framework. We point out two
difficulties that seem to limit this applicability, namely drift dependence and
essential risk aversion independence. We suggest to solve these by a
re-interpretation of the framework. This leads to the notion of an implied
drift. We also present a heuristic derivation of the marginal indifference
price and the marginal optimal hedge that might be useful in numerical
computations.Comment: 23 pages, v2: publishe
C.V.D. annual report: November 1965 research project RU27-1 :an analogue method for the determination of potential distributions in semiconductor systems
A general method for the solution of the nonlinear
Shockley-Poisson differential equation which
governs the potential distribution in non-degenerate
semiconductor systems is described which can be applied
to the evaluation of depletion layer widths, carrier
densities and capacitance bias relationships of p-n
junction structures.
The method is based upon the use of a particular
type of resistance network analogue and results obtained
for several one and two dimensional configurations are
discussed
Explicit solution of an inverse first-passage time problem for L\'{e}vy processes and counterparty credit risk
For a given Markov process and survival function on
, the inverse first-passage time problem (IFPT) is to find a
barrier function such that the survival
function of the first-passage time is given
by . In this paper, we consider a version of the IFPT problem
where the barrier is fixed at zero and the problem is to find an initial
distribution and a time-change such that for the time-changed process
the IFPT problem is solved by a constant barrier at the level zero.
For any L\'{e}vy process satisfying an exponential moment condition, we
derive the solution of this problem in terms of -invariant
distributions of the process killed at the epoch of first entrance into the
negative half-axis. We provide an explicit characterization of such
distributions, which is a result of independent interest. For a given
multi-variate survival function of generalized frailty type, we
construct subsequently an explicit solution to the corresponding IFPT with the
barrier level fixed at zero. We apply these results to the valuation of
financial contracts that are subject to counterparty credit risk.Comment: Published at http://dx.doi.org/10.1214/14-AAP1051 in the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
The Antebellum U.S. Iron Industry: Domestic Production and Foreign Competition
This paper presents new annual estimates of U.S. production of pig iron and imports of pig iron products dating back to 1827. These estimates are used to assess the vulnerability of the antebellum iron industry to foreign competition and the role of the tariff in fostering the industry's early development. Domestic pig iron production is found to be highly sensitive to changes in import prices. Although import price fluctuations had a much greater impact on U.S. production than changes in import duties, our estimates suggest that the tariff permitted domestic output to be about thirty to forty percent larger than it would have been without protection.
Millimeter wavelength spectroscopy and continuum studies of the planets
Careful observations were made at 86.1 GHz to derive the absolute brightness temperatures of the Sun (7914 + or - 192 K), Venus (357.5 + or - 13.1 K), Jupiter (179.4 + or - 4.7K), and Saturn (153.4 + or - 4.8 K) with a standard error of about 3%. This is a significant improvement in accuracy over previous results. A stable transmitter and novel superheterodyne receiver were constructed and used to determine the effective collecting area of the MWO 4.9 m antenna relative to a previously calibrated standard gain horn. The thermal scale was set by calibrating the radiometer with carefully constructed and tested hot and cold loads. The brightness temperatures may be used to establish an absolute calibration scale and to determine the antenna aperture and beam efficiencies of other radio telescopes at 3.5 mm wavelength
Streaming velocities as a dynamical estimator of Omega
It is well known that estimating the pairwise velocity of galaxies, v_{12},
from the redshift space galaxy correlation function is difficult because this
method is highly sensitive to the assumed model of the pairwise velocity
dispersion. Here we propose an alternative method to estimate v_{12} directly
from peculiar velocity samples, which contain redshift-independent distances as
well as galaxy redshifts. In contrast to other dynamical measures which
determine beta = sigma_8 x Omega^{0.6}, our method can provide an estimate of
(sigma_8)^2 x Omega^{0.6} for a range of sigma_8 (here Omega is the
cosmological mass density parameter while sigma_8 is the standard normalization
parameter for the spectrum of matter density fluctuations). We demonstrate how
to measure this quantity from realistic catalogues.Comment: 8 pages of text, 4 figures Subject headings: Cosmology: theory -
observation - peculiar velocities: large scale flows Last name of one of the
authors was misspelled. It is now corrected. Otherwise the manuscript is
identical to its original versio
Arbitrage Bounds for Prices of Weighted Variance Swaps
We develop robust pricing and hedging of a weighted variance swap when market
prices for a finite number of co--maturing put options are given. We assume the
given prices do not admit arbitrage and deduce no-arbitrage bounds on the
weighted variance swap along with super- and sub- replicating strategies which
enforce them. We find that market quotes for variance swaps are surprisingly
close to the model-free lower bounds we determine. We solve the problem by
transforming it into an analogous question for a European option with a convex
payoff. The lower bound becomes a problem in semi-infinite linear programming
which we solve in detail. The upper bound is explicit.
We work in a model-independent and probability-free setup. In particular we
use and extend F\"ollmer's pathwise stochastic calculus. Appropriate notions of
arbitrage and admissibility are introduced. This allows us to establish the
usual hedging relation between the variance swap and the 'log contract' and
similar connections for weighted variance swaps. Our results take form of a
FTAP: we show that the absence of (weak) arbitrage is equivalent to the
existence of a classical model which reproduces the observed prices via
risk-neutral expectations of discounted payoffs.Comment: 25 pages, 4 figure
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