Offline Handwritten Signature Verification - Literature Review

The area of Handwritten Signature Verification has been broadly researched in the last decades, but remains an open research problem. The objective of signature verification systems is to discriminate if a given signature is genuine (produced by the claimed individual), or a forgery (produced by an impostor). This has demonstrated to be a challenging task, in particular in the offline (static) scenario, that uses images of scanned signatures, where the dynamic information about the signing process is not available. Many advancements have been proposed in the literature in the last 5-10 years, most notably the application of Deep Learning methods to learn feature representations from signature images. In this paper, we present how the problem has been handled in the past few decades, analyze the recent advancements in the field, and the potential directions for future research.Comment: Accepted to the International Conference on Image Processing Theory, Tools and Applications (IPTA 2017

Auctioning airport slots (?)

The current allocation of slots on congested European airports constitutes an obstacle to the effective liberalisation of air transportation undertaken in Europe. With a view to favouring efficient slot utilisation and competition, as is the goal of the European commission, we propose to use a market mechanism, based on temporary utilisation licences. In order to allocate those licences, we propose and describe an iterated combinatorial auction mechanism where a percentage of licences would be reallocated each season. A secondary market would also be set up in order to reallocate slots during a season. Since a combinatorial auction involve a complex optimisation procedure, we describe how it can be made to work in the case of auctions.slots; airports; licence; auction; combinatorial

Power of the Spacing test for Least-Angle Regression

Recent advances in Post-Selection Inference have shown that conditional testing is relevant and tractable in high-dimensions. In the Gaussian linear model, further works have derived unconditional test statistics such as the Kac-Rice Pivot for general penalized problems. In order to test the global null, a prominent offspring of this breakthrough is the spacing test that accounts the relative separation between the first two knots of the celebrated least-angle regression (LARS) algorithm. However, no results have been shown regarding the distribution of these test statistics under the alternative. For the first time, this paper addresses this important issue for the spacing test and shows that it is unconditionally unbiased. Furthermore, we provide the first extension of the spacing test to the frame of unknown noise variance. More precisely, we investigate the power of the spacing test for LARS and prove that it is unbiased: its power is always greater or equal to the significance level $\alpha$. In particular, we describe the power of this test under various scenarii: we prove that its rejection region is optimal when the predictors are orthogonal; as the level $\alpha$ goes to zero, we show that the probability of getting a true positive is much greater than $\alpha$; and we give a detailed description of its power in the case of two predictors. Moreover, we numerically investigate a comparison between the spacing test for LARS and the Pearson's chi-squared test (goodness of fit).Comment: 22 pages, 8 figure

Consistent estimation of the filtering and marginal smoothing distributions in nonparametric hidden Markov models

In this paper, we consider the filtering and smoothing recursions in nonparametric finite state space hidden Markov models (HMMs) when the parameters of the model are unknown and replaced by estimators. We provide an explicit and time uniform control of the filtering and smoothing errors in total variation norm as a function of the parameter estimation errors. We prove that the risk for the filtering and smoothing errors may be uniformly upper bounded by the risk of the estimators. It has been proved very recently that statistical inference for finite state space nonparametric HMMs is possible. We study how the recent spectral methods developed in the parametric setting may be extended to the nonparametric framework and we give explicit upper bounds for the L2-risk of the nonparametric spectral estimators. When the observation space is compact, this provides explicit rates for the filtering and smoothing errors in total variation norm. The performance of the spectral method is assessed with simulated data for both the estimation of the (nonparametric) conditional distribution of the observations and the estimation of the marginal smoothing distributions.Comment: 27 pages, 2 figures. arXiv admin note: text overlap with arXiv:1501.0478

When Water is no Longer Heaven Sent: Comparative Pricing Analysis in an AGE Model

In this paper we present a applied general equilibrium model with special features that allows for comparative analysis of different pricing scheme. We look at Boiteux-Ramsey Pricing, Marginal Cost Pricing as well as an arbitrary water pricing increase for the agriculture sectors. A standard AGE was adapted by explicitly modeling water production with its different technologies, water demand by different users also needed to be refined since they are generally modeled with fixed coefficient with no substitution allowed. Results show that the choice of applying one policy over another can rely on the water management authorities (or government)objectives. If considering economic efficiency and water conservation the Boiteux-Ramsey pricing seems to be the best alternative. Moreover, we show that BRP become more clearly advantageous vs MCP the more rigid (small capacities to substitute water for other inputs) the economy's agents.Water, Taxation, Incidence, Computable General Equilibrium Model, Boiteux-Ramsey Pricing, Marginal Cost Pricing

Rivalry in the U.S. Airline Industry

In this paper, we use Market Share Instability (MSI) as a measure of the intensity of competition among airlines on a specific route. This measure is used to capture not only price competition but also non-price competition notably capacity competition. We test the effect of different variables (used in pricing studies) on MSI on a sample of 400 routes over the period 1987 to 1993. Most of the results found in pricing studies are confirmed using this measure of rivalry. For example the presence of a bankrupt carrier increases rivalry but extensive multimarket contact between rivals decreases competition. We also find that MSI was significantly lower in the early nineties when demand conditions were weak. A decline in the intensity of capacity competition could explain that result.

Male-Female Productivity Differentials: the Role of Ability and Incentives

We consider the response to incentives as an explanation for productivity differences within a firm that paid its workers piece rates. We provide a framework within which observed productivity differences can be decomposed into two parts: one due to differences in ability and the other due to differences in the response to incentives. We apply this decomposition to male and female workers a tree-planting firm in the province of British Columbia, Canada. We provide evidence that individuals do react differently to incentives. However, while the women in our sample reacted slightly more to incentives than did the men, the average difference is not statistically significant. The productivity differential that men enjoyed arose because of differences in ability, strength in our application.Productivity, Gender, Compensation, Incentives

Why Banning the Worst Forms of Child Labour Would Hurt Poor Countries

Although it is intuitive and morally compelling that the worst forms of child labour should be eliminated, banning them in poor countries is unlikely to be welfare improving and can come at the expense of human capital accumulation. We show that the existence of harmful forms of child labour, in fact, has an economic role: it helps keep wages for child labour high enough to allow human capital accumulation. Therefore, unless appropriate mechanisms are designed to mitigate the decline in child labour wages caused by reduced employment options for children, a ban on harmful forms of child labour will likely prove undesirable in poor countries. We perform our analysis within a simple two-period model of parental investment in children's education and nutritional quality.Child labour, Human capital, Nutrition, Development

Can Environmental Regulations be Good for Business? an Assessment of the Porter Hypothesis

The Porter hypothesis asserts polluting firms can benefit from environmental policies, arguing that well-designed environmental regulations stimulate innovation, which by increasing either productivity or product value, leads to private benefits. As a consequence, environmental regulations would benefit both society and regulated firms. This point of view has found a receptive audience among policy makers and the popular press but has been severely criticized by economists. In this paper, we present some of the arguments in this debate and review the empirical evidence available so far in the economic literature.Porter Hypothesis, Environmental Regulations, Competitiveness

Inter-Sectorial Risk Pooling and Wage Distributions

This paper develops a model where two agents in different sectors face uncorrelated income risks and mutually self-insure. We discuss how the rent arising from risk pooling modifies the wage distribution in the sector where the employer behaves as a monopsonist.risk pooling, family transfers