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Search Results: 1 - 10 of 94 matches for " Diaraf Seck "
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Scheduling Aircraft Landings at LSS Airport  [PDF]
Coumba Diallo, Babacar Mbaye Ndiaye, Diaraf Seck
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.22027
Abstract: This paper presents a short contribution in air transportation, specifically in scheduling aircraft (plane) landings at Léopol Sédar Senghor (LSS) airport of Dakar. The safety of air navigation of LSS is managed by ASECNA: Agency for Air Navigation Safety in Africa and Madagascar. Scheduling aircraft landing is the problem of deciding a landing time on an appropriate runway for each aircraft in a given set of aircraft such that each aircraft lands within a predetermined time window. The separation criteria between the landing of an aircraft, and the landing of all successive aircraft, are respected. Our objective is to minimize the cost of deviation from the target times. We present a mixed-integer 0 - 1 formulation for the single runway case. Numerical experiments and comparisons based on real datasets of LSS airport are presented.
On the Location of a Free Boundary for American Options  [PDF]
Ronald Katende, Diaraf Seck, Philip Ngare
Journal of Mathematical Finance (JMF) , 2016, DOI: 10.4236/jmf.2016.65062
Abstract: We study the free boundary problem of the American type of options. We consider a continuous dividend paying put option and provide a much simpler way of approximating the option payoff and value. The essence of this study is to apply geometric techniques to approximate option values in the exercise boundary. This, being done with the nature of the exercise boundary in mind, more accurate results are guaranteed. We define a transformation (map) from a unit square to the free boundary. We then examine the transformation and its properties. We take a linear case for a transformation as well as a nonlinear case which would be more fitting for option values. We consider stochasticity (an Ito process) as we define this transformation and this yields better approximations for option values and payoffs. We also numerically compute optimal option prices by using the same transformation. We finally demonstrate that our transformation performs better than most semi-analytic results.
Existence of solutions for the one-phase and the multi-layer free-boundary problems with the p-laplacian operator
Idrissa Ly,Diaraf Seck
Electronic Journal of Differential Equations , 2006,
Abstract: By considering the p-laplacian operator, we show the existence of a solution to the exterior (resp interior) free boundary problem with non constant Bernoulli free boundary condition. In the second part of this article, we study the existence of solutions to the two-layer shape optimization problem. From a monotonicity result, we show the existence of classical solutions to the two-layer Bernoulli free-boundary problem with nonlinear joining conditions. Also we extend the existence result to the multi-layer case.
Isoperimetric inequality for an interior free boundary problem with p-laplacian operator
drissa Ly,Diaraf Seck
Electronic Journal of Differential Equations , 2004,
Abstract: By considering the p-Laplacian operator, we establish an existence and regularity result for a shape optimization problem. From a monotony result, we show the existence of a solution to the interior problem with a free surface for a family of Bernoulli constants. We also give an optimal estimation for the upper bound of the Bernoulli constant.
Topological Optimization with the p-Laplacian Operator and an Application in Image Processing
Alassane Sy,Diaraf Seck
Boundary Value Problems , 2009, DOI: 10.1155/2009/896813
Abstract: We focus in this paper on the theoretical and numerical aspect os image processing. We consider a non linear boundary value problem (the p-Laplacian) from which we will derive the asymptotic expansion of the Mumford-Shah functional. We give a theoretical expression of the topological gradient as well as a numerical confirmation of the result in the restoration and segmentation of images.
Topological Optimization with the -Laplacian Operator and an Application in Image Processing
Sy Alassane,Seck Diaraf
Boundary Value Problems , 2009,
Abstract: We focus in this paper on the theoretical and numerical aspect os image processing. We consider a non linear boundary value problem (the -Laplacian) from which we will derive the asymptotic expansion of the Mumford-Shah functional. We give a theoretical expression of the topological gradient as well as a numerical confirmation of the result in the restoration and segmentation of images.
Poverty Indices Revisited  [PDF]
Eugene Kouassi, Pierre Mendy, Diaraf Seck, Kern O. Kymn
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13027
Abstract: In this paper, a new optimization-based approach to constructing a poverty index is considered. From a general perspective, first and second order conditions based on a general poverty intensity function are derived. Then using specific intensity functions defined by [1,3] respectively, we specify related necessary and sufficient conditions and the underlying poverty indices. An extension based on a large class of intensity function is also investigated.
Dynamic Poverty Measures  [PDF]
Eugene Kouassi, Pierre Mendy, Diaraf Seck, Kern O. Kymn
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13014
Abstract: In this paper one considers a general approach to construct a poverty index. In particular from a general perspective, first and second order conditions based on a general poverty intensity function are derived. Then using specific intensity functions defined by Sen, FGT and Shorrock respectively, one specifies related first and second conditions. An extension based on a large class of intensity function is also investigated.
Numerical Approach of Network Problems in Optimal Mass Transportation  [PDF]
Lamine Ndiaye, Babacar Mbaye Ndiaye, Pierre Mendy, Diaraf Seck
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.35069
Abstract: In this paper, we focus on the theoretical and numerical aspects of network problems. For an illustration, we consider the urban traffic problems. And our effort is concentrated on the numerical questions to locate the optimal network in a given domain (for example a town). Mainly, our aim is to find the network so as the distance between the population position and the network is minimized. Another problem that we are interested is to give an numerical approach of the Monge and Kantorovitch problems. In the literature, many formulations (see for example [1-4]) have not yet practical applications which deal with the permutation of points. Let us mention interesting numerical works due to E. Oudet begun since at least in 2002. He used genetic algorithms to identify optimal network (see [5]). In this paper we introduce a new reformulation of the problem by introducing permutations . And some examples, based on realistic scenarios, are solved.
Breakdown Mechanic Location Problem  [PDF]
Cheikh B. Djiba, Mamadou Balde, Babacar M. Ndiaye, Roger M. Faye, Diaraf Seck
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.35070
Abstract: This paper studies the problem of locating breakdown mechanic. We consider a public transport network in which it can provide buses failure. The objective is, taking into account the statistics of breakdowns registered on the network, to locate optimally breakdown mechanics so as to minimize the response time (to ensure the network coverage of break- down mechanics). In this work, we present a binary linear programming model for this location problem which provides assignments-locations of areas served. Once the location made, we discuss dynamic assignment of breakdown mechan- ics depending on their position in the network at a given time t. Numerical simulation results are presented based on real data of urban transportation society of Dakar Dem Dikk.
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