7,190 research outputs found
Scepticism and the genealogy of knowledge: situating epistemology in time
My overarching purpose is to illustrate the philosophical fruitfulness of expanding epistemology not only laterally across the social space of other epistemic subjects, but at the same time vertically in the temporal dimension. I set about this by first presenting central strands of Michael Williams' diagnostic engagement with scepticism, in which he crucially employs a Default and Challenge model of justification. I then develop three key aspects of Edward Craig's ‘practical explication' of the concept of knowledge so that they may be seen to resonate positively with Williams's epistemological picture: the admixture of internalist and externalist features; the proto-contextualism; and, finally, the distinctively genealogical antisceptical impetus. In this way I aim to support and augment the socialized anti-sceptical case mounted by Williams, and so to show that expanding epistemology in the temporal dimension can be a productive move in central debates in epistemology
Forum on Miranda Fricker's "Epistemic Injustice: Power and the Ethics of Knowing"
This paper summarizes key themes from my Epistemic Injustice: Power and the Ethics of Knowing (OUP, 2007); and it gives replies to commentators
There\u27s a Sigh in the Heart
There\u27s a sigh in the heart, tho\u27 the lip may be gay,When we think of the land, the land far away.Blushing garlands around hang in wreaths from each spray,But the flow\u27rs that I lov\u27d when my spirti was gay,They are fading, unpluck\u27d in the land far away.There\u27s a sigh in the heart, tho\u27 the lip may be gayWhen we think of the land, the land far away.Sadly I gaze on the moon\u27s bright ratmAnd in fancy I follow its track far away.Sadly I list to the NIghtingale\u27s way,No hope of tomorrow to cheer me today.While my eye shall grow dim, and my tresses grow grayStill my last tho\u27t shall be of the land far away
Two-choice regulation in heterogeneous closed networks
A heterogeneous closed network with one-server queues with finite capacity
and one infinite-server queue is studied. A target application is bike-sharing
systems. Heterogeneity is taken into account through clusters whose queues have
the same parameters. Incentives to the customer to go to the least loaded
one-server queue among two chosen within a cluster are investigated. By
mean-field arguments, the limiting queue length stationary distribution as the
number of queues gets large is analytically tractable. Moreover, when all
customers follow incentives, the probability that a queue is empty or full is
approximated. Sizing the system to improve performance is reachable under this
policy.Comment: 19 pages, 4 figure
A Stochastic Model for Car-Sharing Systems
Vehicle-sharing systems are becoming important for urban transportation. In
these systems, users arrive at a station, pick up a vehicle, use it for a while
and then return it to another station of their choice. Depending on the type of
system, there might be a possibility to book vehicles before picking-up and/or
a parking space at the chosen arrival station. Each station has a finite
capacity and cannot host more vehicles and reserved parking spaces than its
capacity. We propose a stochastic model for an homogeneous car-sharing system
with possibility to reserve a parking space at the arrival station when
picking-up a car. We compute the performance of the system and the optimal
fleet size according to a specific metric. It differs from a similar model for
bike-sharing systems because of reservation that induces complexity, especially
when traffic increases
Incentives and Redistribution in Homogeneous Bike-Sharing Systems with Stations of Finite Capacity
Bike-sharing systems are becoming important for urban transportation. In such
systems, users arrive at a station, take a bike and use it for a while, then
return it to another station of their choice. Each station has a finite
capacity: it cannot host more bikes than its capacity. We propose a stochastic
model of an homogeneous bike-sharing system and study the effect of users
random choices on the number of problematic stations, i.e., stations that, at a
given time, have no bikes available or no available spots for bikes to be
returned to. We quantify the influence of the station capacities, and we
compute the fleet size that is optimal in terms of minimizing the proportion of
problematic stations. Even in a homogeneous city, the system exhibits a poor
performance: the minimal proportion of problematic stations is of the order of
(but not lower than) the inverse of the capacity. We show that simple
incentives, such as suggesting users to return to the least loaded station
among two stations, improve the situation by an exponential factor. We also
compute the rate at which bikes have to be redistributed by trucks to insure a
given quality of service. This rate is of the order of the inverse of the
station capacity. For all cases considered, the fleet size that corresponds to
the best performance is half of the total number of spots plus a few more, the
value of the few more can be computed in closed-form as a function of the
system parameters. It corresponds to the average number of bikes in
circulation
An investigation into the effects of solvent content on the image quality and stability of ink jet digital prints under varied storage conditions
Increasing numbers of galleries, museums and archives are including ink jet printed materials into their collections, and therefore displays. There is evidence that the instability of these prints is such that images can suffer deterioration in print quality or in extreme cases, a loss of information over an extended period of time. This is shorter than the period typically required for perceptible deterioration to occur in many other paper-based artworks. The image stability of prints is affected by a number of factors some of which have already been studied. However the role played by the ink solvent in the loss of image quality has yet to be explored. This paper will outline research being undertaken to investigate the effects of solvent content which may increase/promote the loss in image quality of the hard copy prints when stored or displayed under a range of temperature and humidity conditions
Perturbation analysis of an M/M/1 queue in a diffusion random environment
We study in this paper an queue whose server rate depends upon the
state of an independent Ornstein-Uhlenbeck diffusion process so that
its value at time is , where is some bounded
function and . We first establish the differential system for the
conditional probability density functions of the couple in the
stationary regime, where is the number of customers in the system at
time . By assuming that is defined by for some positive real numbers
, and , we show that the above differential system has a
unique solution under some condition on and . We then show that this
solution is close, in some appropriate sense, to the solution to the
differential system obtained when is replaced with
for sufficiently small . We finally
perform a perturbation analysis of this latter solution for small
. This allows us to check at the first order the validity of the
so-called reduced service rate approximation, stating that everything happens
as if the server rate were constant and equal to \mu(1-\eps\E(X(t)))
A versatile and accurate approximation for LRU cache performance
In a 2002 paper, Che and co-authors proposed a simple approach for estimating
the hit rates of a cache operating the least recently used (LRU) replacement
policy. The approximation proves remarkably accurate and is applicable to quite
general distributions of object popularity. This paper provides a mathematical
explanation for the success of the approximation, notably in configurations
where the intuitive arguments of Che, et al clearly do not apply. The
approximation is particularly useful in evaluating the performance of current
proposals for an information centric network where other approaches fail due to
the very large populations of cacheable objects to be taken into account and to
their complex popularity law, resulting from the mix of different content types
and the filtering effect induced by the lower layers in a cache hierarchy
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