Documents found
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2664.More information
The study is about the financial modelling of the advantages offered to the employees of a company. It shows in several steps, the way to build an actuarial model which aim is to evaluate the financial burden of social commitments granted by a company. The aim is to enter the commitments in the accounts, at their fair value, of the relating financial provisions in accordance with the International Financial Reporting Standards (IFRS) defining the employees benefits (IAS 19). It is demonstrated by a concrete example. Said example is the one of a phased-in retirement held at SNCF on 2008 (source : Advisory Board for Pensions (“COR : Conseil d’Orientation des Retraites”), document n°10, 11/02/2009).The aim is to show the complexity of such a modelling in terms of method and of choice of modelling, and the limits of the assumption (theoretical formalisation and calibration). The complexity and major role of human behaviour knowledge are underscored in the light of the estimation of the trust given to the financial assessment obtained.To conclude, it is possible to obtain a tangible range of results to react toward the image of the financial implication. Nevertheless, it does allow to obtain a range of sufficient credibility to handle with trust such social advantages.
Keywords: Modélisation financière, modèle actuariel, Financial modelling, actuarial model
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2666.More information
The problem for operations of reservoirs is to choose on a day to day basis the value of the release at the dam location. The choice of the value of that discharge is conditioned by a criterion of satisfaction of one or several objectives. These objectives are defined in one or several points in the system on the river, or the rivers, downstream from the point, or the points, of release. Typical objectives may be to maximize electric production, or to minimize damage due to flooding downstream from the dams or due to shortages of water in the rivers at diversion points for municipal water supply or other uses, etc.adapted to the concerns of the managers, and relatively intuitive. The approach described in this article pursues the reasoning of Massé (1946) but generalizes it and therefore makes it more applicable. At first we look at the case of a single reservoir, located directly on the stream for the production of electric energy. In this case the target-point (the point where an objective function is to be evaluated) coincides with the point of release. This was precisely the problem studied by Massé (1946) in his classical two volumes on "Reserves and the Regulation of the Future". We pursue his reasoning but we use a more appropriate mathematical procedure which will allow us to obtain more general results. The same results are derived using two different approaches. The first one is more intuitive and uses the concept of marginal value to secure the necessary condition of optimality to be satisfied by the releases. The second procedure is more mathematical and uses, basically, the method of Calculus of Variations, generalized to the case where there are inequality constraints that must be satisfied. In the case of a single reservoir one shows that the optimality condition provides the rigorous proof of the graphical method of Varlet (1923). The results of Massé are generalized to the case where the objective function is evaluated downstream from the point of release and the management strategy must account for the phenomenon of propagation of discharges in the streams. Again in this case the results are obtained in two ways, (1) by the economic reasoning on the marginal values and (2) with the Constrained Calculus of Variations. Massé had found that the optimal policy for the releases was the one that maintained the marginal benefit constant in time. That applied for the case of a single reservoir and where the target-point coincides with the point of release. If B{x(t),t} is the instantaneous benefit obtained from making the release at the dam at a rate x(t) at time t, then the optimality condition is mathematically: b{x(t),t}=L=constant with timewhere b{x(t),t} is the marginal benefit, i.e. the partial derivative of B{x(t),t} with respect to the argument x. L is a constant, which in the mathematical formulation of the problem is the Lagrange multiplier associated with the mass balance constraint to be satisfied over the selected horizon of operations. In other words the cumulative volume of releases over the time horizon must be equal to the cumulative volume of inflows plus the drop in reservoir storage between the initial and final times. Economically the marginal benefit is the incremental benefit realized by making an extra release of one unit of water, given that the rate of release was x(t). Typically the marginal benefit decreases as the rate of release increases and that is often referred to as the "law of decreasing returns". For the case of electric production the marginal benefit will depend on the amount of releases made through the turbines but also on the season of year or day of week or hour of day. The price of electricity is higher in winter than it is in summer. It is higher during peak hours during the week than it is on weekends, etc. If on the other hand the marginal benefit is only a function of the release, and not a function of time, then the constancy of the marginal benefit with time is equivalent to the constancy of the release with time. Optimality becomes synonymous with regulation, i.e. releasing at a constant rate. It is only under these conditions that the graphical method of Varlet is applicable. In the graphical domain of cumulative volume of releases versus time, the optimal "trajectory" is a straight line where such a strategy is feasible i.e. does not make the reservoir more than full nor less than empty. When the objective is evaluated at a point downstream from the point of release and the marginal benefit (or cost) has a seasonal character, neither the graphical procedure of Varlet nor the mathematical result of Massé apply. For this more general case the derived optimality condition states that it is no longer an instantaneous marginal benefit that must remain constant in time. What must remain constant in time is a time integrated and weighted value of the marginal benefit (or damage) between the time the release is made and a later time. That later time is the release time plus the memory of the propagation system. The memory time is the time that must lapse before an upstream release is no longer felt at the target point downstream. The longer the distance between the release point and the target-point the longer is the memory of the propagation system. At the downstream point the damage depends on the discharge at that point, which is of course related to the release rate but also to the lateral inflows in between from tributaries and on the amount of attenuation that happens between the point of release and the target-point downstream. The integrand at dummy integration time t' is the marginal damage at that time multiplied by the instantaneous unit hydrograph at that time. Mathematically the integrand is: f{q(t'),t'}*k(t'-t) where f is marginal damage, q(t') is discharge at target point and k(.) is instantaneous unit hydrograph of propagation between release and target points. This integrand is to be integrated between time t of the release and time t + M, where M is the memory of the system. It is that integral that we have called the "Integrated Marginal Future" (or IMF for short) value that must remain constant in time. That optimality condition applies as long as the trajectory remains in the feasible domain bounded by the constraints of the problem, the "interior domain". When on a bound, the IMF value does not remain constant but must vary monotonically in a given direction, i.e. increases or decreases with time, depending on the constraint on which the solution rests.
Keywords: Optimisation, exploitation de réservoirs, gestion des eaux, modèle de grands bassins, temps de propagation, crues, étiages, Optimization, reservoir operations, water resources management, large scale river basin model, propagation time, floods, low flows augmentation
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2667.More information
Cataloging documents taken from the Internet is truly challenging. Several projects undertaken in the United States, such as OCLC Internet Resources and Intercat Project, the Text Encoding Initiative (TEI), and the OCLC Dublin Core Project, helped to identify major problems. Tools such as URCs, URNs and PURLs were developed to assist cataloguers in bringing order to the chaos of Internet. The article describes those projects and tools used to identify the problems encountered by cataloguers in the course of their work. Finally, the levels of competency required by cataloguers in the future and their role in establishing standards for information exchange in the Internet community are briefly discussed.
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2669.More information
This paper attempts to show that gender inequality exists in training persons with entrepreneurial intention, before they begin entrepreneurship. We surveyed 229 male and 211 female students in the first, second and third year of the bachelor programme, and at the Master’s level in management at “grandes écoles” (higher education institutions) in Gabon. The data come from a questionnaire submitted to them. A quantitative methodology with hypothetical-deductive logic was used, as well as multi-group structural equation modelling on persons with entrepreneurial intention. The results show that women have a higher entrepreneurial intention than men before they go into business. Female predispositions dominate those of men, notably attitude, determination, perceived social norms, exposure to entrepreneurship/business experience, and perceived self-efficacy. These determinants of entrepreneurial intention evolve more for women than for men, except for perceived social norms. The determinants that trigger women’s entrepreneurial actions dominate those of men, except for attitude and perceived social norms, which are equal.
Keywords: Intention entrepreneuriale, Entrepreneurial, intention, femmes, hommes, women, clivage, men, entrepreneuriat, divide, entrepreneurship
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2670.More information
AbstractIn this 1985 paper, the author reacts to the notion of copyright laws in the context of a pop culture environment that had transcended the brick-and-mortar principles in which the law was based. The artist leads us to understand the end of the producer-consumer paradigm: “After decades of being the passive recipients of music in packages, listeners now have the means to assemble their own choices, to separate pleasures from the filler. They are dubbing a variety of sounds from around the world, or at least from the breadth of their record collections, making compilations of a diversity unavailable from the music industry, with its circumscribed stables of artists, and an ever more pervasive policy of only supplying the common denominator.” Perhaps one of the strongest ideas in Oswald's paper is rooted in the fact that, by acting as a tight filter focused on big moneymaking hits, most record labels had already entered a vulnerable space in which their final product is not entirely theirs anymore. Oswald clearly articulates why the music -industry, powered by radio [among other distribution vehicles], lost their archaic right to have a tight ownership of every bit of sound. [Camilo La Cruz]