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Home tenure, stock market participation, and composition of the household portfolio
No full textIn this study, we empirically analyze the simultaneous decisions of households to participate in the stock market and/or own their home. A vast literature stream exists on decisions to buy or rent a home, and many contributions report the low participation rate of American households in the US stock market. Numerous authors have also provided evidence that home tenure (modeled as an exogenous variable) affects the share of household portfolios held as stocks. However, the present study is the first to allow decisions on homeownership and stockholding to be simultaneous and endogenous. We use a dynamic bivariate logistic panel data model on the Panel Study of Income Dynamics data from 1999 to 2007, controlling for sample selection bias and time-invariant unobserved heterogeneity. These estimates allow us to simulate the individual paths of homeownership and stockholding status over whole life cycles, according to household characteristics. Ceteris paribus, we show that households acquiring one asset (either home or stocks) acquire the other at an earlier stage in their life cycles, implying that some households become trapped in a no-stockholding, renting position.nonouirechercheInternationa
Solidarités familiales et conditions de vie étudiante : des disparités objectives aux inégalités perçues
No full textnonouirechercheNationa
Satisfying more than half of a system of linear equations over GF(2): A multivariate approach
No full textIn the parameterized problem MaxLin2-AA[k ], we are given a system with variables x1,…,xnx1,…,xn consisting of equations of the form ∏i∈Ixi=b∏i∈Ixi=b, where xi,b∈{−1,1}xi,b∈{−1,1} and I⊆[n]I⊆[n], each equation has a positive integral weight, and we are to decide whether it is possible to simultaneously satisfy equations of total weight at least W/2+kW/2+k, where W is the total weight of all equations and k is the parameter (it is always possible for k=0k=0). We show that MaxLin2-AA[k ] has a kernel with at most View the MathML sourceO(k2logk) variables and can be solved in time 2O(klogk)(nm)O(1)2O(klogk)(nm)O(1). This solves an open problem of Mahajan et al. (2006). The problem Max-r-Lin2-AA[k,rk,r] is the same as MaxLin2-AA[k] with two differences: each equation has at most r variables and r is the second parameter. We prove that Max-r-Lin2-AA[k,rk,r] has a kernel with at most (2k−1)r(2k−1)r variables.nonouirechercheInternationa
Semi-algebraic sets and equilibria of binary games
No full textAny nonempty, compact, semi-algebraic set in [0,1]^n is the projection of the set of mixed equilibria of a finite game with 2 actions per player on its first n coordinates. A similar result follows for sets of equilibrium payoffs. The proofs are constructive and elementary.nonnonrechercheInternationa
Elicitation of a Utility from Uncertainty Equivalent Without Standard Gambles
No full textLNCS n°9161In the context of decision under uncertainty, standard gambles are classically used to elicit a utility function on a set X of consequences. The utility of an element x in X is derived from the probability p for which a gamble giving the best outcome in X with probability p and the worst outcome in X otherwise, is indifferent to getting x for sure. In many situations, uncertainty that can be observed on the true value of X concerns only neighbour values. Uncertainty is then represented by a probability distribution whose support is an interval. In this case, standard gambles are unrealistic for the decision maker. We consider uncertainty represented by an equi-probability over an interval of X. This paper addresses the elicitation of a utility function on X by obtaining the certainty equivalent of an equi-probability over an interval of X. We show that not all utility models are suitable to accomplish this task.nonnonrechercheInternationa
Evaluation of user satisfaction with OLAP recommender systems: an application to RecoOLAP on a agricultural energetic consumption datawarehouse
No full textOLAP and datawarehouse (DW) systems are technologies intended to support the decision-making process, enabling the analysis of a substantial volume of data. One of the goals of recommender systems is to help users navigate large amounts of data. OLAP recommender systems have recently been proposed in the literature because the multidimensional analysis process is often tedious because the user may not know what the forthcoming query should be. User satisfaction with these systems has not yet been investigated. Thus, this work is the first study of the usefulness of OLAP recommender systems from the decision maker's point of view. Indeed, to the best of our knowledge, although several works have proposed OLAP recommender systems, they did not evaluate them against real-world data and users. With our experiments on a spatial DW concerning agricultural energetic consummation issued from the Energetic French Project.nonouirechercheInternationa
A variable neighbourhood search algorithm for the hospital case mix planning problem
No full textThe hospital case mix planning problem resides in the determination of a tactical plan of patients of several pathology groups so as to allocate at best available resources over the horizon. This problem can be formulated as a mixed integer program. As exact methods fail to provide the optimal solution in a reasonable time, we develop a VNS algorithm with neighbourhoods defined in terms of plan changes. Exploration is performed using two operators : period change (one patient is moved to another period) and swap (patients of two groups in two periods are exchanged).nonouirechercheInternationa
Searching Linked Data and Services with a Single Query
No full textThe appearance of valuable Linked Data sources as part of the LOD in the last few years and the emergence of Semantic Web services has opened new horizons for web and data research. Moreover, machine-understandability of semantics allows for efficient search and integration of data. Based on the existing standards and techniques, we address the problem of searching data and services in the LOD. Furthermore, we aim to introduce an approach that integrates data queries with data from service calls and compositions. However, many challenges and issues need to be resolved in order to achieve such a goal. In this paper we briefly discuss some of such problems and solutions.nonouirechercheInternationa
A Multilevel Agent-Based Approach for Trustworthy Service Selection in Social Networks
No full textThe growing number of services available within social applications (viz. Social networks) raises a new and challenging search issue: selecting desired services from social networks. Traditional discovery and selection approaches, which are registry-based (e.g., UDDI, ebXML), have manifested their limitations as they often fall behind users' expectations. This is because registries fail to (i) take into consideration non functional properties such as QoS and trust and (ii) capitalize on the information resulting from the previous experiences between agents. To address these shortcomings, we use software agents as they support interactions and offer well-developed capabilities to formally express and interpret semantic information useful to evaluate trust. Trust in a service is a multi-aspect concept that includes a social-based aspect such as judging whether the provider is worthwhile pursuing before using his services (viz. Trust in sociability), expert-based aspect such as estimating whether the service behaves well and as expected (viz. Trust in expertise) and, recommender-based aspect such as assessing whether an agent is reliable and we can rely on its recommendations (viz. Trust in recommendation).nonouirechercheInternationa
Solving one-to-one integrated production and outbound distribution scheduling problems with job release dates and deadlines
No full textIn this paper, we study an integrated production and outbound distribution scheduling problem with one manufacturer and one customer. The manufacturer has to process a set of jobs and deliver them in batches to the customer. Each job has a release date and a delivery deadline. The objective of the problem is to decide a feasible integrated production and distribution schedule minimizing the transportation cost subject to the delivery deadline constraints. We consider three problems with different ways how a job can be produced and delivered: Non-splittable production and delivery (NSP-NSD) problem, Splittable production and non-splittable delivery (SP-NSD) problem and Splittable production and delivery (SP-SD) problem. We provide a polynomial-time algorithm that solves two special cases of problems SP-NSD and SP-SD. We also develop a B&B algorithm that solves the NP-hard problem NSP-NSD. The computational results show that the B&B algorithm outperforms an ILP formulation of the problem implemented on a commercial solver.nonnonrechercheInternationa