460 research outputs found
Basic Income in 1848
This note introduces a virtually unknown social constitution drafted in Brussels in 1848, in which an unconditional basic income figured prominently. We provide details on the historical and intellectual context in which the proposal originated, and briefly compare it with similar proposals of the same period. In the appendix, we present an English translation of the constitution
Putting the cart before the horse. A comment on Wagstaff on inequality measurement in the presence of binary variables
Adam Wagstaff's (2011) recent paper sends a strong reminder that binary variables occur frequently in health inequality studies and that it is important to examine whether the standard measurement tools can be applied without any modification when the health variable happens to be binary. In his note, he reconsiders what he wrote previously on the subject (Wagstaff, 2005), in the light of recent work on bounded variables (Clarke et al., 2002; Erreygers, 2009a, 2009b; Wagstaff, 2009; Erreygers and Van Ourti, 2011). Although Wagstaff's contribution undoubtedly enriches a much-needed debate, crucial aspects of his paper seriously misrepresent the positions and views set forth in Erreygers and Van Ourti (2011). In this note, we would like to put the record straight, focusing on five specific points
First steps towards an imprecise Poisson process
The Poisson process is the most elementary continuous-time stochastic process that models a stream of repeating events. It is uniquely characterised by a single parameter called the rate. Instead of a single value for this rate, we here consider a rate interval and let it characterise two nested sets of stochastic processes. We call these two sets of stochastic process imprecise Poisson processes, explain why this is justified, and study the corresponding lower and upper (conditional) expectations. Besides a general theoretical framework, we also provide practical methods to compute lower and upper (conditional) expectations of functions that depend on the number of events at a single point in time
Imprecise continuous-time Markov chains : efficient computational methods with guaranteed error bounds
Imprecise continuous-time Markov chains are a robust type of continuous-time Markov chains that allow for partially specified time-dependent parameters. Computing inferences for them requires the solution of a non-linear differential equation. As there is no general analytical expression for this solution, efficient numerical approximation methods are essential to the applicability of this model. We here improve the uniform approximation method of Krak et al. (2016) in two ways and propose a novel and more efficient adaptive approximation method. For ergodic chains, we also provide a method that allows us to approximate stationary distributions up to any desired maximal error
Fourierist legacies: from the âRight to the Minimumâ to âBasic Incomeâ
The origins of the idea of a âbasic incomeâ remain to be fully explored. An idea with currency mainly in Europe, a basic income is conventionally defined as an income unconditionally granted to all on an individual basis, irrespective of the level of any income from other sources, and without any work requirements. In this article we examine the completely neglected contribution of an elusive Belgian, Joseph Charlier, to the spasmodic history of proposals for a basic income and its cognates
Bounding inferences for large-scale continuous-time Markov chains : a new approach based on lumping and imprecise Markov chains
If the state space of a homogeneous continuous-time Markov chain is too large, making inferences becomes computationally infeasible. Fortunately, the state space of such a chain is usually too detailed for the inferences we are interested in, in the sense that a less detailedâsmallerâstate space suffices to unambiguously formalise the inference. However, in general this so-called lumped state space inhibits computing exact inferences because the corresponding dynamics are unknown and/or intractable to obtain. We address this issue by considering an imprecise continuous-time Markov chain. In this way, we are able to provide guaranteed lower and upper bounds for the inferences of interest, without suffering from the curse of dimensionality
First Steps Towards an Imprecise Poisson Process
The Poisson process is the most elementary continuous-time stochastic process
that models a stream of repeating events. It is uniquely characterised by a
single parameter called the rate. Instead of a single value for this rate, we
here consider a rate interval and let it characterise two nested sets of
stochastic processes. We call these two sets of stochastic process imprecise
Poisson processes, explain why this is justified, and study the corresponding
lower and upper (conditional) expectations. Besides a general theoretical
framework, we also provide practical methods to compute lower and upper
(conditional) expectations of functions that depend on the number of events at
a single point in time.Comment: Extended pre-print of a paper accepted for presentation at ISIPTA
201
Imprecise Markov Models for Scalable and Robust Performance Evaluation of Flexi-Grid Spectrum Allocation Policies
The possibility of flexibly assigning spectrum resources with channels of
different sizes greatly improves the spectral efficiency of optical networks,
but can also lead to unwanted spectrum fragmentation.We study this problem in a
scenario where traffic demands are categorised in two types (low or high
bit-rate) by assessing the performance of three allocation policies. Our first
contribution consists of exact Markov chain models for these allocation
policies, which allow us to numerically compute the relevant performance
measures. However, these exact models do not scale to large systems, in the
sense that the computations required to determine the blocking
probabilities---which measure the performance of the allocation
policies---become intractable. In order to address this, we first extend an
approximate reduced-state Markov chain model that is available in the
literature to the three considered allocation policies. These reduced-state
Markov chain models allow us to tractably compute approximations of the
blocking probabilities, but the accuracy of these approximations cannot be
easily verified. Our main contribution then is the introduction of
reduced-state imprecise Markov chain models that allow us to derive guaranteed
lower and upper bounds on blocking probabilities, for the three allocation
policies separately or for all possible allocation policies simultaneously.Comment: 16 pages, 7 figures, 3 table
Modelling Spectrum Assignment in a Two-Service Flexi-Grid Optical Link with Imprecise Continuous-Time Markov Chains
Flexi-grid optical networks (Gerstel et al., 2012) are a novel paradigm for managing the capacity of optical fibers more efficiently. The idea is to divide the spectrum in small frequency slices, and to consider an allocation policy that adaptively assigns one or multiple contiguous slices to incoming bandwidth requests, depending on their size. However, as new requests arrive and old requests are served and return resources to the free pool, the spectrum might become fragmented, leading to inefficiency and unfairness.
It is therefore necessary to quantify the performance of a given spectrum allocation policy, for example by determining the probability that a bandwidth request is blocked, in the sense that it cannot be allocated because there are not enough contiguous free slices.
To determine blocking probabilities for an optical link with traffic requests of two different sizes and a random allocation policy, Kim et al. (2015) use a Markov chain. Unfortunately, the number of states of this Markov chain grows exponentially with the number of available frequency slices, making it infeasible to determine blocking probabilities for large systems.
Therefore, Kim et al. (2015) also consider a second Markov chain, with a highly reduced state space and approximate transition rates, to obtain approximations of these blocking probabilities. In this contribution, we first show how to construct such full and reduced-state Markov chains for two other allocation policies, and compare these with the random policy.
Next, we introduce a so-called imprecise Markov chain, which has the same reduced state space but imprecise (interval-valued) transition rates, and explain how it can be used to determine guaranteed upper and lower bounds for --- instead of approximations of --- blocking probabilities, for different families of allocation policies
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