1,356,413 research outputs found
El Magreb i la nova política europea de veïnatge
No full textConferència a càrrec d'Azzam Mahjoub, professor de la University of Tunis El-Manar234.mp
Compositions of Graphs and the Triangle-Free Subgraph Polytope
No full textIn this paper, we study a composition (decomposition) technique for the triangle-free subgraph polytope in graphs which are decomposable by means of 3-sums satisfying some property. If a graph G decomposes into two graphs G 1 and G 2, we show that the triangle-free subgraph polytope of G can be described from two linear systems related to G 1 and G 2. This gives a way to characterize this polytope on graphs that can be recursively decomposed. This also gives a procedure to derive new facets for this polytope. We also show that, if the systems associated with G 1 and G 2 are TDI, then the system characterizing the polytope for G is TDI. This generalizes previous results in R. Euler and A.R. Mahjoub (Journal of Comb. Theory series B, vol. 53, no. 2, pp. 235–259, 1991) and A.R. Mahjoub (Discrete Applied Math., vol. 62, pp. 209–219, 1995).ou
Steiner k-edge connected subgraph polyhedra
No full textIn this paper we consider the Steiner k-edge survivable network problem. We discuss the polytope
associated with the solutions to that problem. We show that when the graph is series-parallel and k is even,
the polytope is completely described by the trivial constraints and the so called Steiner-cut constraints. This
generalizes recent work of Ba¨ ıou and Mahjoub, SIAM J. Discrete Mathematics, vol. 10, pp. 505–514, 1997 for
the case k D 2. As a consequence, we obtain in this case a linear description of the polyhedron associated with
the problem when multiple copies of an edge are allowed.ou
Représentation sociale et représentation « scientifique»: Syndromes culturels ou mystification du statut social ?
No full textKi-covers I: Complexity and polytopes
No full textAbstractA Ki in a graph is a complete subgraph of size i. A Ki-cover of a graph G(V, E is a set C of Ki − 1's of G such that every Ki in G contains at least one Ki − 1 in C. Thus a K2-cover is a vertex cover. The problem of determining whether a graph has a Ki-cover (i ⩾ 2) of cardinality ⩽k is shown to be NP-complete for graphs in general. For chordal graphs with fixed maximum clique size, the problem is polynomial; however, it is NP-complete for arbitrary chordal graphs when i ⩾ 3. The NP-completeness results motivate the examination of some facets of the corresponding polytope. In particular we show that various induced subgraphs of G define facets of the Ki-cover polytope. Further results of this type are also produced for the K3-cover polytope. We conclude by describing polynomial algorithms for solving the separation problem for some classes of facets of the Ki-cover polytope
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Spontaneous Rupture of the Kidney Due to Acute Lymphoblastic Leukemia: The First Episode and a Glance on the Literature
No full textSpontaneous rupture of the kidney consists of the atraumatic disruption of the renal parenchyma, followed by hemorrhage or leakage of urine into the perinephric space.
A17 years old male known case of Acute Lymphoblastic Leukemia (ALL), referred to the urology department with right loin pain and fever for 3days. There was no history of trauma. Investigations revealed low hemoglobin, low platelets 18000 and urine analysis showed pus cells 14-18 cell/HPF and RBCs 2-4 /HPF. Renal functions tests and coagulation profile were normal. CT urography showed bulky right kidney with mid pole laceration leaking of the contrast in the perinephric space
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
A min-max relation for K3-covers in graphs noncontractible to K5e
No full textAbstractIn Euler and Mahjoub (1991) it is proved that the triangle-free subgraph polytope of a graph noncontractible to K5e is completely described by the trivial inequalities and the so-called triangle and odd wheel inequalities. In this paper we show that the system denned by those inequalities is TDI for a subclass of that class of graphs. As a consequence we obtain the following min-max relation: If G is a graph noncontractible to K5e, then the minimum number of edges covering all the triangles of G equals the maximum profit of a partition of the edge set of G into edges, triangles and odd wheels. Here the profit of an edge is 0, the profit of a triangle is 1 and the profit of a 2k + 1-wheel (k ϵ N) is equal to k + 1
Caracterización geofísica de los "greens" de un campo de golf regado con agua regenerada. Aproximación textural e hidrológica
No full textMàster oficial: Aigua. Anàlisi Interdisciplinària i Gestió Sostenible. Institut de Recerca de l'Aigua, curs: 2010, Tutors: Josefina C. Tapias i Mahjoub HimiEste estudio tiene la finalidad de caracterizar los "greens" de un campo de golf desde un punto de vista edáfico, así como geofísico. Si bien han habido diferentes trabajos que han estudiado los campos de golf a partir de datos edáficos, la utilización de un método geofísico como la tomografía eléctrica para caracterizar los campos de golf no ha sido muy común. La correlación de los análisis químicos, físicos y físico-químicos con la información extraída de la geofísica constituye el carácter innovador del presente trabajo; asimismo al utilizar diferentes técnicas se aborda el problema con la pluridisciplinaridad que da nombre al propio Máster
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