Dissertations / Theses on the topic 'Tur\'{a}n problem'
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1
Breed, Elizabeth Alice. "'n Metakognitiewe onderrigleerstrategie vir paarprogrammeerders ter verbetering van kennisproduktiwiteit / Elizabeth Alice Breed." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4367.
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Metacognition in collaborative learning settings is an emerging topic in research on
metacognition. This study focused on the development of metacognitive skills during pair
programming in order to enhance knowledge productivity. Pair programming entails
collaboration between two programmers, each fulfilling a specific role during the execution of
the programming task, and has recently been used in educational contexts as a teaching and
learning strategy to improve learning in computer programming (DeClue, 2003:49; Preston,
2006b:16). In this study the outcomes of collaborative learning during pair programming are
referred to as knowledge productivity, which is measured against the criteria of enhanced
knowledge construction, enhanced problem-solving skills, conceptual changes in individual
perspectives, commitment to work with the other member of the pair, and application of the
results of the learning process (Tillema & Van der Westhuizen, 2006:51,55). To investigate the
influence of a metacognitive teaching and learning approach to pair programming on knowledge
productivity, a repeated-measures experiment with a control group was conducted among a
number of Grade 11 learners who had been implementing pair programming in the learning of
Information Technology at secondary school level. At the beginning of the study both groups
completed two questionnaires, one on metacognition and the other on knowledge productivity.
At the same stage, a number of randomly selected participants from each group were
interviewed on the same two topics, using a semi-structured interview approach. This
procedure was repeated three months later, without any intervention. During the intervention
phase, the experimental group implemented a set of self-directed metacognitive questions that they had to answer while doing a pair programming task. These self-directed metacognitive questions form part of a metacognitive teaching and learning strategy suggested by the researcher. The members of the experimental group also kept a journal to describe how the
self-directed questions directed their thinking during the execution of the pair programming task.
At the end of the experimental period, the mo questionnaires on metacognition and knowledge
productivity were completed by both groups again, supported by the interviews of the same
selected participants. The results derived from the empirical study showed that the knowledge
productivity of learners programming in pairs can be enhanced by implementing a metacognitive
teaching and learning strategy. The metacognitive teaching and learning strategy implemented during this study was then adapted to make it suitable for use by teachers and learners during pair programming.Thesis (Ph.D. (Education)--North-West University, Potchefstroom Campus, 2010.
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Coba, Caballero Dulce Mar��a. "Expectativas del segmento l��sbico gay sobre la oferta tur��stica." Thesis, Universidad de las Am��ricas Puebla, 2010. http://catarina.udlap.mx/u_dl_a/tales/documentos/lhr/coba_c_dm/.
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El turismo rosa est�� formado por el segmento l��sbico gay, el cual es un grupo con altos beneficios econ��micos para el turismo, ya que est�� acostumbrado a darse lujos y viajar constantemente. La oferta tur��stica para el segmento l��sbico gay es poca, por lo que se desean saber las expectativas que tiene el segmento sobre lugares como hoteles, restaurantes, centros nocturnos, entre otros. A partir de la investigaci��n, se pudo conocer los or��genes del segmento, el crecimiento del turismo l��sbico gay, al igual que la amplitud de la oferta existente. Saber la importancia de las expectativas del consumidor para proveer una oferta interesante e innovadora para dicho segmento. Se menciona el impacto que tienen las experiencias en los consumidores, y en consecuencia, su comportamiento. Fue importante saber acerca de la discriminaci��n y la aceptaci��n del segmento l��sbico gay. A trav��s de entrevistas profundas, se pudo conocer las caracter��sticas que busca el segmento l��sbico gay en la oferta tur��stica(cont.) Se muestran las caracter��sticas que buscan para lugares como hoteles y restaurantes, al igual que sus preferencias y gustos para algunos establecimientos. Se exponen las incomodidades y molestias en varios lugares visitados. Y por ��ltimo, se mencionan los destinos gay friendly m��s importantes y frecuentados a nivel mundial
3
Xie, Zhifu. "On the N-body Problem." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1444.pdf.
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Hernandez, David Michael. "Solving the N-body problem in astrophysics." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119107.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 299-307).
The astrophysical N-body problem describes N point masses interacting with each other through pairwise gravitational forces. A solution of this problem is frequently necessary in dynamical astronomy. In the collisional N-body problem, the relaxation time is small compared to the timescale we are interested in studying. Collisional N-body problems include open and globular clusters and protoplanetary disks during the stage, typically lasting hundreds of Myrs, when planetary embryos collide and merge. In the first part of this Thesis, I develop new symplectic integrators which provide a solution for the N-body problem. The integrators decompose the N-body problem into a superposition of two-body problems, which are integrable. Since they are symplectic, the integrators conserve all Poincaré invariants (the evolution is Hamiltonian). We used the integrators to compute the evolution of a globular cluster through core collapse up to 20 times faster than standard techniques. In the second part of this Thesis, I apply the results from the first part of the Thesis to planetary dynamics finding that for problems with hierarchical binaries (planets with moons, planetary systems with binary stars, etc.), the integrators are far more efficient than alternatives. I show numerically that a popular code is neither symplectic nor time-symmetric, and can yield incorrect three-body dynamics. I derive symplectic integrators in various coordinate systems with different Hamiltonian splittings and compare them through backward error analysis and tests of Pluto's orbital element evolution. The final part of this Thesis is concerned with time-symmetric and time-reversible integration in astrophysics, whether we are integrating the N-body problem or other ordinary differential equations. These integrators have been proposed as an alternative to symplectic integration. I show, again using backward error analysis, that such integrators are usually useful, but can behave worse than symplectic integrators. I find time-reversibility can be eliminated in some cases while good error behavior is still maintained.
by David Michael Hernandez.
Ph. D.
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Arruda, Alian Paiva de. "Os "farofeiros" em excurs?o nas lagoas de Arituba, Bo?gua e Carcar? (N?sia Floresta/RN): an?lise de uma outra face do turismo potiguar." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/18904.
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Previous issue date: 2010-06-11This thesis analyzes another side of Potiguar tourism , the unplanned side, neglected and kept out of touristic activities: excursionism, a leisure practice enjoyed by tourists with low consumer power, and who are commonly referred by the pejorative term farofeiros (picnic lovers). The geographic research sites considered for this study include Arituba, Bo?gua and Carcar? lakes in N?sia Florest, Rio Grande do Norte, where on Sundays and holidays the arrival of hundreds of excursionists, from around the metropolitan region of Natal, from surrounding municipalities, and neighboring States, such as Para?ba and Pernambuco, can be observed. The objective of this study is to analyze the appropriation of the physical site by the practice of excursionism, focusing on its relation to other social agents that also appropriate a designated touristic area. The theoretical discussion considers the use of the space by the touristic leisure practice and the appropriation by distinct social agents, using categories of analysis, such as, production of the space, territory and leisure. The field work was completed with interviews and questionnaires administered to excursionists, excursion organizers, local merchants, representatives of the public setor from the municipalities, and professional dune buggy drivers; besides this, photos, informal dialogue and field observations were important methodological instruments used. From the data, statistical analysis and the development of thematic maps demonstrating the established flux between excursionists and the segregated activity were done. With this research, one can affirm that the practice of excursionism is neglected by the public sector, contrary to the intention of the hegemonic agent?s intentionality present in this touristic territory which aim at the development of a lucrative activity, geared toward tourists with greater spending power. This ignored and neglected faction of Potiguar tourism is considered poor or dirty , and generate conflicts among the distinct social agents: tourists, the market and the public sector, simultaneously peaking interest, which is then appropriated by the informal sector and formal economy. Excursionism is an expressive phenomenon, a socially relevant practice, enjoyed by citizens of the working class who, in order to have a day of leisure, use alternative consumer practices and subvert various strategies of segregation that are imposed within these tourist areas, behavior that, in part, justifies the nickname, picnic lovers , given to these tourists
Esta disserta??o analisa uma outra face do turismo potiguar , a face n?o planejada, negligenciada e segregada da atividade tur?stica. Trata-se do estudo do excursionismo, uma pr?tica de lazer tur?stico realizada por turistas com baixo poder de consumo, denominados pejorativamente de farofeiros , pelo senso comum. O recorte espacial da pesquisa compreende as lagoas de Arituba, Bo?gua e Carcar? (N?sia Floresta/RN), onde se observa nos dias de domingo e feriados a chegada de centenas de excursionistas, oriundos da Regi?o Metropolitana de Natal, de outros munic?pios do entorno e de estados vizinhos, como Para?ba e Pernambuco. O objetivo desta pesquisa ? analisar como se d? a apropria??o do espa?o pela pr?tica do excursionismo enfocando suas rela??es com outros agentes sociais os quais, tamb?m, se apropriam de um territ?rio tur?stico. A discuss?o te?rica considera o consumo do espa?o pela pr?tica do lazer tur?stico e a apropria??o por distintos agentes sociais, utilizando categorias de an?lise como produ??o do espa?o, territ?rio e lazer. A pesquisa de campo foi realizada por meio de entrevistas e aplica??o de question?rios, junto aos excursionistas, organizadores das excurs?es, comerciantes locais, representantes do poder p?blico municipal e da categoria profissional de bugueiros; al?m disto, o registro fotogr?fico, di?logos informais e a observa??o em campo foram instrumentos metodol?gicos importantes. A partir dos dados realizaram-se an?lises estat?sticas e elabora??o de mapas tem?ticos os quais expressam os fluxos estabelecidos pelos excursionistas e a segrega??o da atividade. Com a pesquisa, pode-se afirmar que a pr?tica do excursionismo ? negligenciada pelo poder p?blico, pois esta contraria a intencionalidade dos agentes hegem?nicos presentes neste territ?rio tur?stico uma vez que este visam o desenvolvimento de uma atividade lucrativa, voltada para turistas com maior poder de consumo. Observa-se nesta face ignorada do turismo potiguar, tida como pobre e suja , a exist?ncia de conflitos entre os distintos agentes sociais: turistas, comerciantes locais e poder p?blico, ao mesmo tempo em que, tamb?m, desperta o interesse e ? apropriada pelo setor informal e formal da economia. O excursionismo ? um fen?meno expressivo, uma pr?tica social relevante, realizada por cidad?os que comp?em a classe trabalhadora os quais, para terem um dia de lazer, utilizam-se de pr?ticas alternativas de consumo e burlam variadas estrat?gias de segrega??o que lhes s?o impostas neste territ?rio tur?stico, comportamentos que, em parte justifica a alcunha de farofeiro dada a estes turistas
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Valentini, Gabriele. "The Best-of-n Problem in Robot Swarms." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/232502.
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Collective decision making can be seen as a means of designing and understanding swarm robotics systems. While decision-making is generally conceived as the cognitive ability of individual agents to select a belief based only on their preferences and available information, collective decision making is a decentralized cognitive process, whereby an ensemble of agents gathers, shares, and processes information as a single organism and makes a choice that is not attributable to any of its individuals. A principled selection of the rules governing this cognitive process allows the designer to define, shape, and foresee the dynamics of the swarm.We begin this monograph by introducing the reader to the topic of collective decision making. We focus on artificial systems for discrete consensus achievement and review the literature of swarm robotics. In this endeavor, we formalize the best-of-n problem—a generalization of the logic underlying several cognitive problems—and define a taxonomy of its possible variants that are of interest for the design of robot swarms. By leveraging on this understanding, we identify the building-blocks that are essential to achieve a collective decision addressing the best-of-n problem: option exploration, opinion dissemination, modulation of positive feedback, and individual decision-making mechanism. We show how a modular perspective of a collective decision-making strategy allows for the systematic modeling of the resulting swarm performance. In doing so, we put forward a modular and model-driven design methodology that allows the designer to study the dynamics of a swarm at different level of abstractions. Successively, we employ the proposed design methodology to derive and to study different collective decision-making strategies for the best-of-n problem. We show how the designed strategies can be readily applied to different real-world scenarios by performing two series of robot experiments. In the first series, we use a swarm of 100 robots to tackle a site-selection scenario; in the second series, we show instead how the same strategies apply to a collective perception scenario. We conclude with a discussion of our research contributions and provide futuredirection of research.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Alhowaity, Sawsan Salem. "Relative equilibria in the curved N-body problem." Thesis, Canadian Mathematical Bulletin, 2018. https://dspace.library.uvic.ca//handle/1828/10037.
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We consider the curved N-body problem, N > 2, on a surface of constant Gaussian curvature κ ≠ 0; i.e., on spheres S2κ, for κ > 0, and on hyperbolic manifolds H2κ, for κ < 0. Our goal is to define and study relative equilibria, which are orbits whose mutual distances remain constant during the motion. We find new relative equilibria in the curved N-body problem for N = 4, and see whether bifurcations occur when passing through κ = 0. After obtaining a criterion for the existence of quadrilateral configurations on the equator of the sphere, we study two restricted 4-body problems: One in which two bodies are massless , and the second in which only one body is massless. In the former we prove the evidence for square-like relative equilibria, whereas in the latter we discuss the existence of kite-shaped relative equilibria.
We will further study the 5-body problem on surfaces of constant curvature. Four of the masses arranged at the vertices of a square, and the fifth mass at the north pole of S2κ, when the curvature is positive, it is shown that relative equilibria exists when the four masses at the vertices of the square are either equal or two of them are infinitesimal, such that they do not affect the motion of the remaining three masses. In the hyperbolic case H2κ, κ < 0, there exist two values for the angular velocity which produce negative elliptic relative equilibria when the masses at the vertices of the square are equal. We also show that the square pyramidal relative equilibria with non-equal masses do not exist in H2κ.
Based on the work of Florin Diacu on the existence of relative equilibria for 3-body problem on the equator of S2κ, we investigate the motion of more than three bodies. Furthermore, we study the motion of the negative curved 2-and 3-centre problems on the Poincaré upper semi-plane model. Using this model, we prove that the 2-centre problem is integrable, and we study the dynamics around the equilibrium point. Further, we analyze the singularities of the 3- centre problem due to the collision; i.e., the configurations for which at least two bodies have identical coordinates.Graduate
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Steiger, Don. "Numerical n-body methods in computational chemistry /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9924930.
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Stadel, Joachim Gerhard. "Cosmological N-body simulations and their analysis /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/5449.
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Urminsky, David. "Stability and numerical errors in the N-body problem." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/9804.
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Despite the wide acceptance that errors incurred in numerical solutions to N-body systems grow exponentially, most research assumes that the statistical results of these systems are reliable. However, if one is to accept that the statistical results of N-body solutions are reliable, it is important to determine if there are any systematic statistical errors resulting from the incurred growth of errors in individual solutions. In this thesis we consider numerical solutions to the 3-body problem in which one of the bodies escapes the system. It is shown for a particular 3-body con guration, known as the Sitnikov problem, that the mean lifetime of the system is dependent on the accuracy of the numerical integration. To provide a theoretical explanation of the phenomenon, an approximate Poincar´e map is developed whose dynamics on a particular surface of section is shown to be similar to the dynamics of the Sitnikov Problem. In fact there is a set on which the approximate Poincar´e map is topologically equivalent, like the Sitnikov Problem, to the shift map on the set of bi-in nite sequences. The structure of the escape regions on the surface of section form a cantor set-like structure whose boundary can more easily be delineated using the approximate Poincar´e map than for the Sitnikov problem. Further it is shown that numerical errors destroy escape regions and can cause orbits to migrate to a region in which escape is faster. Finally, a relationship between the Lyapunov time, tl, and the lifetime, td, of the 3-body problem is discussed. Firstly, the Sitnikov problem and the approximate Poincar´e map of the Sitnikov problem both exhibit a two-part power law relationship beween tl and td like that for a particular case of the general 3-body problem. Further, it is demonstrated that large perturbations to the energy of the escaping body in uences the relationship between tl and td for small tl. Finally, it is shown that the approximate Poincar´e map yields a theoretical explanation of the phenomenon based on the structure of the escape regions the orbits traverse before escape.
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Ong, James Kwan Yau. "The predictability problem." Phd thesis, kostenfrei, 2007. http://opus.kobv.de/ubp/volltexte/2007/1502/.
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Dale, Edward Robert. "Visualizing the inner structure of n-body data using splatting and skeletonization /." Link to online version, 2006. https://ritdml.rit.edu/dspace/handle/1850/2071.
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Chalmers, James Handson. "The group of an N-body problem in celestial mechanics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0020/NQ48325.pdf.
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Chalmers, James Handson Carleton University Dissertation Mathematics. "The Group of an N-body problem in celestial mechanics." Ottawa, 1999.
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Swiderski, Rafal. "The Sparling-Tod type N space-time and the googly problem." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514999.
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Sharaf, Khadijah Abdullah Mohammed. "On the prescribed mean curvature problem on the standard n-dimensional ball." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28493.
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In this thesis, we consider the problem of existence of conformal scalar flat metric with prescribed boundary mean curvature on the standard n-dimensional ball. Let B[superscript n] be the unit ball in R[superscript n], n ≥ 3, with Euclidean metric g[subscript 0]. Its boundary will be denoted by S[superscript n-1] and will be endowed with the standard metric still denoted by g[subscript 0]. Let H : S[superscript n-1] → R be a given function, we study the problem of finding a conformal metric g = u 4/n-2 g[subscript 0] such that R[subscript g] = 0 in B[superscript n] and h[subscript g] = H on S[superscript n-1]. Here R[subscript g] is the scalar curvature of the metric g in B[superscript n] and h[subscript g] is the mean curvature of g on S[superscript n-1]. This problem is equivalent to solving the following nonlinear boundary value equation: (see PDF for equation) where v is the outward unit vector with respect to the metric g[subscript 0]. In general there are several difficulties in facing this problem by means of variational methods. Indeed, in virtue of the non-compactness of the embedding H[superscript 1](B[superscript n]) → L 2(n-1)/n-2 (∂B[superscript n]), the Euler-Lagrange functional J associated to the problem, does not satisfy the Palais-Smale condition, and that leads to the failure of the standard critical point theory. One part of this thesis deals with the case where H is a Morse function satisfying a non degeneracy condition. Using an algebraic topological method and the tools of the theory of the critical points at infinity, we provide a variety of classes of functions that can be realized as the mean curvature on the boundary of the the n-dimensional balls. The other part deals with the case where the non degeneracy condition is not satisfied and replaced by the so called β-flatness condition. In this case, we give precise estimates on the losses of the compactness and we identify the critical points at infinity of the variational problem. Then, we establish under generic boundary condition a Morse inequalities at infinity, which give a lower bound on the number of solutions to the above problem.
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Iuliano, Jay R. "A Solution to the Circular Restricted N Body Problem in Planetary Systems." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1612.
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This thesis is a brief look at a new solution to a problem that has been approached in many different ways in the past - the N body problem. By focusing on planetary systems, satellite dynamics can be modeled in a fashion similar to the Circular Restricted Three Body Problem (CR3BP) with the Circular Restricted N Body Problem (CRNBP). It was found that this new formulation of the dynamics can then utilize the tools created from all the research into the CR3BP to reassess the possibility of different complex trajectories in systems where there are more than just two large gravitational bodies affecting the dynamics, namely periodic and semi-periodic orbits, halo orbits, and low energy transfers It was also found that not only system dynamics, but models of the Jacobi constant could also be formulated similarly to the CR3BP. Validating the authenticity of these new sets of equations, the CRNBP dynamics are applied to a satellite in the Earth-Moon system and compared to a simulation of the CR3BP under identical circumstances. This test verified the dynamics of the CRNBP, showing that the two systems created almost identical results with relatively small deviations over time and with essentially identical path trends. In the Jovian system, it was found the mass ratio required to validated the assumptions required to integrate the equations of motion was around .1$\%$. Once the mass ratio grew past that limit, trajectories propagated with the CRNBP showed significant deviation from trajectories propagated with a higher fidelity model of Newtonian motion. The results from the derivation of the Jacobi constant are consistent with the 3 body system, but they are fairly standalone.
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Yan, Duokui. "Four-body Problem with Collision Singularity." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3111.pdf.
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Dai, Qianhui [Verfasser]. "Periodic solutions of the N point-vortex problem in planar domains / Qianhui Dai." Gießen : Universitätsbibliothek, 2014. http://d-nb.info/106882557X/34.
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Reina, Andreagiovanni. "Engineering swarm systems: A design pattern for the best-of-n decision problem." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/232717.
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The study of large-scale decentralised systems composed of numerous interacting agents that self-organise to perform a common task is receiving growing attention in several application domains. However, real world implementations are limited by a lack of well-established design methodologies that provide performance guarantees. Engineering such systems is a challenging task because of the difficulties to obtain the micro-macro link: a correspondence between the microscopic description of the individual agent behaviour and the macroscopic models that describe the system's dynamics at the global level. In this thesis, we propose an engineering methodology for designing decentralised systems, based on the concept of design patterns. A design pattern provides a general solution to a specific class of problems which are relevant in several application domains. The main component of the solution consists of a multi-level description of the collective process, from macro to micro models, accompanied by rules for converting the model parameters between description levels. In other words, the design pattern provides a formal description of the micro-macro link for a process that tackles a specific class of problems. Additionally, a design pattern provides a set of case studies to illustrate possible implementation alternatives both for simple or particularly challenging scenarios. We present a design pattern for the best-of-n, decentralised decision problem that is derived from a model of nest-site selection in honeybees. We present two case studies to showcase the design pattern usage in (i) a multiagent system interacting through a fully-connected network, and (ii) a swarm of particles moving on a bidimensional plane.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Lloyd, Gemma. "Morse theory for invariant functions and its application to the n-body problem." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506273.
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Gebhard, Björn [Verfasser]. "An equivariant degree and periodic solutions of the N-vortex problem / Björn Gebhard." Gießen : Universitätsbibliothek, 2018. http://d-nb.info/1161339442/34.
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Holman, Matthew Jon. "Symplectic maps for the N-body problem with applications to solar system dynamics." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/54394.
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Luo, Ping. "Design and Implementation of High Performance Algorithms for the (n,k)-Universal Set Problem." [College Station, Tex. : Texas A&M University, 2009. http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-7033.
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Jedrey, Richard M. "Development of a Discretized Model for the Restricted Three-Body Problem." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306856595.
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Jordaan, Yolandi Maria. "Die assessering van die probleme wat onderwysers binne klasverband ervaar en hul behoefte aan die benutting van 'n spelterapeut." Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-10252004-102706.
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Parker, Christopher Alonzo. "K x N Trust-Based Agent Reputation." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/702.
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In this research, a multi-agent system called KMAS is presented that models an environment of intelligent, autonomous, rational, and adaptive agents that reason about trust, and adapt trust based on experience. Agents reason and adapt using a modification of the k-Nearest Neighbor algorithm called (k X n) Nearest Neighbor where k neighbors recommend reputation values for trust during each of n interactions. Reputation allows a single agent to receive recommendations about the trustworthiness of others. One goal is to present a recommendation model of trust that outperforms MAS architectures relying solely on direct agent interaction. A second goal is to converge KMAS to an emergent system state where only successful cooperation is allowed. Three experiments are chosen to compare KMAS against a non-(k X n) MAS, and between different variations of KMAS execution. Research results show KMAS converges to the desired state, and in the context of this research, KMAS outperforms a direct interaction-based system.
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Juttu, Sreekanth. "A new approach for fast potential evaluation in N-body problems." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/351.
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Fast algorithms for potential evaluation in N-body problems often tend to be extremely abstract and complex. This thesis presents a simple, hierarchical approach to solving the potential evaluation problem in O(n) time. The approach is developed in the field of electrostatics and can be extended to N-body problems in general. Herein, the potential vector is expressed as a product of the potential matrix and the charge vector. The potential matrix itself is a product of component matrices. The potential function satisfies the Laplace equation and is hence expressed as a linear combination of spherical harmonics, which form the general solutions of the Laplace equation. The orthogonality of the spherical harmonics is exploited to reduce execution time. The duality of the various lists in the algorithm is used to reduce storage and computational complexity. A smart tree-construction strategy leads to efficient parallelism at computation intensive stages of the algorithm. The computational complexity of the algorithm is better than that of the Fast Multipole Algorithm, which is one of the fastest contemporary algorithms to solve the potential evaluation problem. Experimental results show that accuracy of the algorithm is comparable to that of the Fast Multipole Algorithm. However, this approach uses some implementation principles from the Fast Multipole Algorithm. Parallel efficiency and scalability of the algorithms are studied by the experiments on IBM p690 multiprocessors.
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Schilling, Judith [Verfasser], and N. [Akademischer Betreuer] Henze. "Untersuchungen zur Asymptotik und zum Erwartungswert im verallgemeinerten Coupon-Collector-Problem / Judith Schilling ; Betreuer: N. Henze." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1207392987/34.
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Simmons, Skyler C. "Analysis of Multiple Collision-Based Periodic Orbits in Dimension Higher than One." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5584.
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We exhibit multiple periodic, collision-based orbits of the Newtonian n-body problem. Many of these orbits feature regularizable collisions between the masses. We demonstrate existence of the periodic orbits after performing the appropriate regularization. Stability, including linear stability, for the orbits is then computed using a technique due to Roberts. We point out other interesting features of the orbits as appropriate. When applicable, the results are extended to a broader family of orbits with similar behavior.
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Wang, Qingyang. "A study of transient bottlenecks: understanding and reducing latency long-tail problem in n-tier web applications." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54002.
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An essential requirement of cloud computing or data centers is to simultaneously achieve good performance and high utilization for cost efficiency. High utilization through virtualization and hardware resource sharing is critical for both cloud providers and cloud consumers to reduce management and infrastructure costs (e.g., energy cost, hardware cost) and to increase cost-efficiency. Unfortunately, achieving good performance (e.g., low latency) for web applications at high resource utilization remains an elusive goal. Both practitioners and researchers have experienced the latency long-tail problem in clouds during periods of even moderate utilization (e.g., 50%). In this dissertation, we show that transient bottlenecks are an important contributing factor to the latency long-tail problem. Transient bottlenecks are bottlenecks with a short lifespan on the order of tens of milliseconds. Though short-lived, transient bottleneck can cause a long-tail response time distribution that spans a spectrum of 2 to 3 orders of magnitude, from tens of milliseconds to tens of seconds, due to the queuing effect propagation and amplification caused by complex inter-tier resource dependencies in the system. Transient bottlenecks can arise from a wide range of factors at different system layers. For example, we have identified transient bottlenecks caused by CPU dynamic voltage and frequency scaling (DVFS) control at the CPU architecture layer, Java garbage collection (GC) at the system software layer, and virtual machine (VM) consolidation at the application layer. These factors interact with naturally bursty workloads from clients, often leading to transient bottlenecks that cause overall performance degradation even if all the system resources are far from being saturated (e.g., less than 50%). By combining fine-grained monitoring tools and a sophisticated analytical method to generate and analyze monitoring data, we are able to detect and study transient bottlenecks in a systematic way.
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Xiao, Bo. "Parallel algorithms for generalized N-body problem in high dimensions and their applications for bayesian inference and image analysis." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53052.
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In this dissertation, we explore parallel algorithms for general N-Body problems in high dimensions, and their applications in machine learning and image analysis on distributed infrastructures.
In the first part of this work, we proposed and developed a set of basic tools built on top of Message Passing Interface and OpenMP for massively parallel nearest neighbors search. In particular, we present a distributed tree structure to index data in arbitrary number of dimensions, and a novel algorithm that eliminate the need for collective coordinate exchanges during tree construction. To the best of our knowledge, our nearest neighbors package is the first attempt that scales to millions of cores in up to a thousand dimensions.
Based on our nearest neighbors search algorithms, we present "ASKIT", a parallel fast kernel summation tree code with a new near-far field decomposition and a new compact representation for the far field. Specially our algorithm is kernel independent. The efficiency of new near far decomposition depends only on the intrinsic dimensionality of data, and the new far field representation only relies on the rand of sub-blocks of the kernel matrix.
In the second part, we developed a Bayesian inference framework and a variational formulation for a MAP estimation of the label field for medical image segmentation. In particular, we propose new representations for both likelihood probability and prior probability functions, as well as their fast calculation. Then a parallel matrix free optimization algorithm is given to solve the MAP estimation. Our new prior function is suitable for lots of spatial inverse problems.
Experimental results show our framework is robust to noise, variations of shapes and artifacts.
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Oliveira, Danielle Aparecida da Silva. "Estabilidade espectral no problema carregado de n-corpos." Pós-Graduação em Matemática, 2018. http://ri.ufs.br/jspui/handle/riufs/7670.
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In this work we will study the linear stability of a relative equilibrium in the charged nbody
problem. To do this, we will introduce the definition of spectral stability of relative
equilibria and we will find conditions necessary to have such stability. We will start
the work by showing relevant results in the theory of differentials equations, highlighting
some important theorems, such as Existence and Uniqueness Theorem, theorems for linear
stability, Floquet’s Theorem and Lyapunov Stability and Instability Theorems. We will do
a concise study of Hamiltonian systems, in which we will provide results and definitions
that will be of great utility during the dissertation. Among such definitions deserves
attention the center configurations (C.C.), since we will show results relating them to
the relative equilibria. We will introduce the concept of spectral stability and we will
see propositions and theorems for the of n-body problem. An example will be displayed
brings a particularity to the charged problem and that makes it very different from the
classic n-body problem. Finally, we will apply the results obtained in the charged 3-body
problem.Neste trabalho faremos o estudo da estabilidade linear de um equilíbrio relativo no problema carregado de n-corpos. Para isso, introduziremos a definição de estabilidade espectral de um equilíbrio e encontraremos condições necessárias para termos tal estabilidade. Começaremos o trabalho mostrando resultados relevantes na teoria de equações diferenciais, dando destaque a alguns teoremas importantes, como por exemplo, Teorema de Existência e Unicidade, teoremas para estabilidade linear, Teorema de Floquet e Teoremas de Estabilidade e Instabilidade de Lyapunov. Será feito um estudo bastante conciso dos sistemas Hamiltonianos, no qual enunciaremos resultados e definições que serão de grande utilidade no decorrer da dissertação. Entre tais definições merece destaque a de configurações centrais (C.C.), uma vez que exibiremos resultados relacionando-as aos equilíbrios relativos. Introduziremos o conceito de estabilidade espectral e veremos proposições e teoremas para o problema carregado de n-corpos. Será exibido um exemplo que traz uma particularidade ao problema carregado e que o diferencia bastante do problema clássico de n-corpos. Por fim, faremos uma aplicação dos resultados obtidos ao problema carregado de 3-corpos.
São Cristóvão, SE
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Campos, Serrano Juan. "Modèles attractifs en astrophysique et biologie : points critiques et comportement en temps grand des solutions." Phd thesis, Université Paris Dauphine - Paris IX, 2012. http://tel.archives-ouvertes.fr/tel-00861568.
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Dans cette thèse, nous étudions l'ensemble des solutions d'équations aux dérivées partielles résultant de modèles d'astrophysique et de biologie. Nous répondons aux questions de l'existence, mais aussi nous essayons de décrire le comportement de certaines familles de solutions lorsque les paramètres varient. Tout d'abord, nous étudions deux problèmes issus de l'astrophysique, pour lesquels nous montrons l'existence d'ensembles particuliers de solutions dépendant d'un paramètre à l'aide de la méthode de réduction de Lyapunov-Schmidt. Ensuite un argument de perturbation et le théorème du Point xe de Banach réduisent le problème original à un problème de dimension finie, et qui peut être résolu, habituellement, par des techniques variationnelles. Le reste de la thèse est consacré à l'étude du modèle Keller-Segel, qui décrit le mouvement d'amibes unicellulaires. Dans sa version plus simple, le modèle de Keller-Segel est un système parabolique-elliptique qui partage avec certains modèles gravitationnels la propriété que l'interaction est calculée au moyen d'une équation de Poisson / Newton attractive. Une différence majeure réside dans le fait que le modèle est défini dans un espace bidimensionnel, qui est expérimentalement consistant, tandis que les modèles de gravitationnels sont ordinairement posés en trois dimensions. Pour ce problème, les questions de l'existence sont bien connues, mais le comportement des solutions au cours de l'évolution dans le temps est encore un domaine actif de recherche. Ici nous étendre les propriétés déjà connues dans des régimes particuliers à un intervalle plus large du paramètre de masse, et nous donnons une estimation précise de la vitesse de convergence de la solution vers un profil donné quand le temps tend vers l'infini. Ce résultat est obtenu à l'aide de divers outils tels que des techniques de symétrisation et des inégalités fonctionnelles optimales. Les derniers chapitres traitent de résultats numériques et de calculs formels liés au modèle Keller-Segel
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Hartell, Cycil George. "'n Histories opvoedkundige studie van gesinsopvoeding in skole." Thesis, Pretoria : [s.n.], 2000. http://upetd.up.ac.za/thesis/available/etd-03162006-152553.
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Kohne, Jens. "Drei Betrachtungen zum Problem der Eigenschaften dargestellt anhand der Lehren von H. H. Price, G. F. Stout und N. Kemp Smith /." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10806357.
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Souza, Izabela Julliane Barbosa de. "Paisagem, um patrim?nio esquecido: subs?dios para a constru??o de uma metodologia de valora??o e prote??o do cen?rio natural litor?neo." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12409.
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Previous issue date: 2014-03-07The so-called "residential tourism" came to intensify the previous occupation of the coastal zones, characterized by traditional beach houses, and brought significant consequences for their spatial configuration, and especially for its scenic value of the landscape. Although there is the intention to regulate the activities of enterprising groups by some legal instruments to control the use and occupation of land, and to contain some negative effects, the actions of government are still inefficient in trying to follow the implications on the landscape from the accelerated growth of the real estate and touristic sectors. Supported in the speech of economic development and income generation, public managers prioritize areas to attract tourists to the detriment of preserving important physical attributes of the natural environment that contribute significantly to the quality of life. The result can be noticed in the use of natural elements as one of the major components in the land valorization, and in the immediate attraction of investors and enterprising. Therefore, the objective of this work is to contribute to the debate on the landscape preservation a little detailed thematic in view of their relevance in the current context - by indicating subsidies to the creation of a methodology for the evaluation and protection of coastal zones that may assist the government in creating new instruments, and better prepare it in control of the occupation of these areas. For such, was followed two ways to analysis: the indirect method and the direct method. The first is grounded in the evaluation of landscape attributes, which is based on the work of Raquel Tardin (2008) and Eduardo Cuesta, Encarnaci?n Algarra and Isabel Pastor (2001). The second, based on the research of Leticia and Carlos Hardt (2010) and on the concepts of phenomenology - expressed by Antonio Christofoletti (1985) and Yi-Fu Tuan (1983) - considers the population perspective on the quality of the natural scenery. Developed through cartographic materials, photographic collections and quantitative tables, this dissertation utilized as a case study the beaches of Barra de Tabatinga and Camurupim, located in the city of N?sia Floresta/RN. Despite already being sighted spaces of advanced stage of landscape degradation in these locations, areas of remarkable scenic value can still be found, what reinforce the urgency in adopting preservationists actions. The absence of laws focused on the management and protection of the landscape singularities associated with the inefficiency of the government to invigilate the land occupation in coastal zones, encourage the excessive action of the real estate-tourism, and consequently make the government the main responsible for the environmental and landscape impacts in these areas - by its omission or by their connivance. Therefore, the legislation permeates this entire process and constitutes itself as the most effective way to guarantee the right to the landscape to present and future generations. Are also pointed some important considerations to build a methodology, especially concerning possibilities of improvements and adaptations of its applicability in each case
O chamado turismo residencial veio intensificar a anterior ocupa??o das zonas litor?neas, marcada pelas tradicionais casas de veraneio, o que trouxe consequ?ncias expressivas para sua configura??o espacial e, sobretudo, para o seu valor c?nico paisag?stico. Embora exista o intento de regular a atua??o de grupos empreendedores atrav?s de alguns instrumentos legais no controle do uso e ocupa??o do solo, e assim conter alguns efeitos negativos, as a??es do poder p?blico ainda se mostram ineficientes na tentativa de acompanhar as implica??es na paisagem advindas do acelerado crescimento dos setores imobili?rio e tur?stico. Apoiados no discurso do desenvolvimento econ?mico e da gera??o de renda, gestores p?blicos findam por privilegiar espa?os de atra??o de turistas em detrimento da preserva??o de atributos f?sicos importantes do cen?rio natural que contribuem de forma significativa para a qualidade de vida da popula??o. O resultado pode ser percebido no uso dos elementos naturais como um dos principais componentes na valoriza??o do solo, e na atra??o imediata de investidores e empreendedores. Dessa forma, objetiva-se com este trabalho contribuir para o debate sobre a preserva??o da paisagem tem?tica ainda pouco aprofundada em face de sua relev?ncia no contexto atual atrav?s da indica??o de subs?dios para a cria??o de uma metodologia de avalia??o e prote??o das zonas litor?neas que possa vir a auxiliar o poder p?blico na cria??o de novos instrumentos, e melhor prepar?-lo no controle da ocupa??o dessas ?reas. Para isso, seguiu-se dois caminhos de an?lise: o m?todo indireto e o m?todo direto. O primeiro se alicer?a na avalia??o de atributos paisag?sticos, no qual se toma como base os trabalhos de Raquel Tardin (2008) e Eduardo Cuesta, Encarnaci?n Algarra e Isabel Pastor (2001). J? o segundo, fundamentado na pesquisa de Let?cia e Carlos Hardt (2010) e em conceitos da fenomenologia expressos por Antonio Christofoletti (1985) e Yi-Fu Tuan (1983) considera a perspectiva da popula??o acerca da qualidade do cen?rio natural por ela percebido. Desenvolvida por meio de materiais cartogr?ficos, acervos fotogr?ficos e tabelas quantitativas, esta disserta??o utilizou como estudo de caso as praias de Barra de Tabatinga e Camurupim, situadas no munic?pio de N?sia Floresta/RN. Apesar de j? serem avistados espa?os de avan?ado est?gio de degrada??o paisag?stica nestas localidades, ainda podem ser encontradas ?reas de ineg?vel valor c?nico, o que refor?a a urg?ncia na ado??o de medidas preservacionistas. A aus?ncia de leis focadas na gest?o e prote??o das singularidades da paisagem, associada ? inefici?ncia do poder p?blico em fiscalizar a ocupa??o do solo nas zonas costeiras, favorecem a a??o desmedida do imobili?rio-tur?stico, e, por isso, tornam o Estado o maior respons?vel pelos impactos ambientais e paisag?sticos nessas ?reas seja pela sua omiss?o, seja pela sua coniv?ncia. Destarte, a legisla??o permeia todo esse processo e se configura como o meio mais eficaz na garantia do direito ? paisagem ?s presentes e futuras gera??es. Por fim, s?o tamb?m apontadas considera??es importantes para a constru??o de uma metodologia, especialmente no que tange possibilidades de aperfei?oamentos e adapta??es de sua aplicabilidade em cada caso de estudo
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Boldrini, Pierre. "The cusp-core problem in dwarf galaxies : new solutions." Thesis, Sorbonne université, 2020. http://www.theses.fr/2020SORUS082.
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Cette thèse porte sur la nature de la matière noire (MN) et plus particulièrement sur le problème de la disparité des profils de densité interne de MN dans les galaxies naines, le problème « cusp-core". Nous avons commencé par réétudier ce problème pour la galaxie naine, Fornax, en utilisant la distribution spatiale et de masse des amas globulaires observée afin de contraindre le profil de MN. Ensuite, nous avons démontré avec des simulations N-corps que les minihalos de MN, en tant que nouvelle composante des amas globulaires, résolvent à la fois le "timing problem" et le problème "cusp-core" dans Fornax — dans le cas où les amas globulaires ont été récemment accrétés. Par ailleurs, nous avons examinés si les candidats de MN sous la forme de trous noirs primordiaux (TNP) peuvent résoudre ce problème dans les galaxies de faible masse. Ce mécanisme fonctionne pour les TNPs entre 25 et 100 Msol mais nécessite que la masse de la population de TNPs soit plus de 1% de la masse totale de MN dans les galaxies naines. Ensuite, nous avons démontré qu'en transférant de l’énergie par friction dynamique dans le centre des galaxies naines, le trou noir central est éjecté à des dizaines de parsecs. Enfin, nous démontrons que l'accrétion d'un satellite sur une orbite très excentrique provoque la formation d'un coeur de MN et explique également que le trou noir central soit décentré dans M31This doctoral research focuses on the nature of the dark matter (DM) and more particularly on the inconsistency of inner DM density profiles in dwarf galaxies, the cusp-core problem. We have found new resolutions of this cold DM challenge at small scales using high resolution fully GPU N-body simulations. First, we have re-investigated the Fornax cusp-core problem using observational results on the spatial and mass distributions of globular clusters in order to put constraints on the DM profile. Then, N-body simulations were designed to demonstrate that DM minihalos, as a new component of globular clusters, resolve both the timing and cusp-core problems in Fornax if the globular clusters were recently accreted. Secondly, we have examined whether DM candidates in the form of PBHs can solve the cusp-core problem in low-mass galaxies. This mechanism works for PBHs in the 25-100 Msol mass window but requires a lower limit on the PBH mass fraction of 1% of the total dwarf galaxy DM content. Then, we have demonstrated that subhalos sink and transfer energy via dynamical friction into the centres of dwarf galaxies. This dynamical heating kicks any central intermediate massive BH out to tens of parsecs. Finally, we demonstrate that accretion of a satellite on a highly eccentric orbit causes the formation a DM core and naturally explains a present BH offset by sub-parsecs in M31
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Riegel, Ryan Nelson. "Generalized N-body problems: a framework for scalable computation." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50269.
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In the wake of the Big Data phenomenon, the computing world has seen a number of computational paradigms developed in response to the sudden need to process ever-increasing volumes of data. Most notably, MapReduce has proven quite successful in scaling out an extensible class of simple algorithms to even hundreds of thousands of nodes. However, there are some tasks---even embarrassingly parallelizable ones---that neither MapReduce nor any existing automated parallelization framework is well-equipped to perform. For instance, any computation that (naively) requires consideration of all pairs of inputs becomes prohibitively expensive even when parallelized over a large number of worker nodes.
Many of the most desirable methods in machine learning and statistics exhibit these kinds of all-pairs or, more generally, all-tuples computations; accordingly, their application in the Big Data setting may seem beyond hope. However, a new algorithmic strategy inspired by breakthroughs in computational physics has shown great promise for a wide class of computations dubbed generalized N-body problems (GNBPs). This strategy, which involves the simultaneous traversal of multiple space-partitioning trees, has been applied to a succession of well-known learning methods, accelerating each asymptotically and by orders of magnitude. Examples of these include all-k-nearest-neighbors search, k-nearest-neighbors classification, k-means clustering, EM for mixtures of Gaussians, kernel density estimation, kernel discriminant analysis, kernel machines, particle filters, the n-point correlation, and many others. For each of these problems, no overall faster algorithms are known. Further, these dual- and multi-tree algorithms compute either exact results or approximations to within specified error bounds, a rarity amongst fast methods.
This dissertation aims to unify a family of GNBPs under a common framework in order to ease implementation and future study. We start by formalizing the problem class and then describe a general algorithm, the generalized fast multipole method (GFMM), capable of solving all problems that fit the class, though with varying degrees of speedup. We then show O(N) and O(log N) theoretical run-time bounds that may be obtained under certain conditions. As a corollary, we derive the tightest known general-dimensional run-time bounds for exact all-nearest-neighbors and several approximated kernel summations.
Next, we implement a number of these algorithms in a commercial database, empirically demonstrating dramatic asymptotic speedup over their conventional SQL implementations. Lastly, we implement a fast, parallelized algorithm for kernel discriminant analysis and apply it to a large dataset (40 million points in 4D) from the Sloan Digital Sky Survey, identifying approximately one million quasars with high accuracy. This exceeds the previous largest catalog of quasars in size by a factor of ten and has since been used in a follow-up study to confirm the existence of dark energy.
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Botha, S. (Sonja). "'n Ondersoek na die rol van strukturele groepfaktore en groepprosesse met betrekking tot bestuurspaninnoverendheid." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52962.
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Thesis (MA)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: Innovation and creativity are established research areas but both are relatively new research areas within the field of organisational psychology. Early research on innovation and creativity were primarily the focus area of academics in related social sciences disciplines. Research on innovation and creativity was integrated with the orientations and perspectives of organisational psychologists over a period of time. In other words the development and identification of innovation as a success factor of the work environment is something that took place over decades. Changes in the competitive environment over the last few decades contributed to the increasing interest in the concept of innovation. Today managers recognise innovation as a necessity that needs to be managed and developed. Three levels of analyses (the individual, group and organisation) can be identified in the innovation literature. Until recently researchers focused primarily on the individual and the organisation as units of analysis. As a results of this, research that focuses on the individual and the organisation are quite comprehensive compared to studies that focus on the group as a unit of analysis. The utilisation of teams have increased in organisations, but our knowledge of the factors and dimensions that determine group innovation are still restricted. The complex nature of group innovation could perhaps be a contributing factor in terms of the amount of research studies that have been done on group innovation. It is especially in this regard that this study sets out to thoroughly investigate existing group innovation literature and to combine this with an investigation into the possible contributions of related social psychological research (for example group decision making, intragroup conflict and creative problem solving) to the innovation literature. Each one of the three units of analysis (individual, group and organisation) has a unique impact on group innovation, but not one of them explains exclusively the innovativeness of a team. An interdependent relationship exists between these factors. This stresses the complexity of the concept and as a result of this, researchers are encouraged to investigate the possible contributions of related social psychological themes to the innovation research and literature. In this regard this study focused extensively on a input, process and output model of group innovation by West and Anderson (1996) to determine to what extend some of the aspects of the model explained the innovativeness of a group. This is a comprehensive model and for the purposes of this study only certain aspects of the model were included in the research process. The size of the team and team tenure were the two input elements that were included in the study. The process elements of the model includes clarity and commitment to team objectives, participation, task orientation and support for innovation. In terms of the output aspects of the model the focus was on the following: how radical, effective, new and extensive the innovation is, as well as the number of innovations per team. The results of the study indicate that there are a relationship between the variables of West and Anderson's input, process and output model (1996) and the innovativeness of the team. The results of this study indicate that the model by West and Anderson is a valuable contribution to the research literature on group innovation behaviour. Although group innovation has not been researched extensively, it seems that group innovation is starting to make an impact on the organisational psychology domain and that it will be a central aspect of the research agenda of organisational psychologists in future. If we are able to establish a sound theoretical basis organisations will be able to understand and predict group innovation behaviour. It can be concluded that this study made a contribution to the research literature on group innovation behaviour in terms of an awareness of the impact and necessity of innovation in today's work environment, and also in extending the existing knowledge base of group innovation behaviour
AFRIKAANSE OPSOMMING: Alhoewel innovasie al VIr 'n geruime tyd as navorsingsdomein gevestig IS, het organisasiesielkundiges eers redelik onlangs aan innovasie en kreatiwiteit begin aandag skenk. Een van die redes waarom dit so lank geneem het voordat innovasie as 'n waardige wetenskaplike navorsingsonderwerp besef was, was die feit dat vroeëre navorsing oor hierdie onderwerp deur akademici in ander sosiaal wetenskaplike dissiplines uitgevoer was. Die integrering van sodanige navorsing met organisasiesielkundiges se perspektiewe en oriëntasies het skynbaar slegs met verloop van tyd plaasgevind. Die ontwikkeling van innovasie as 'n verskynsel van die werksomgewing het dus stelselmatig oor dekades heen plaasgevind. Die impak van omgewingsveranderinge op organisasies het ook oor die afgelope paar dekades beduidende belangstelling ten opsigte van innovasie ontsluit. Innovasie, as 'n komponent van organisatoriese-kompeterendheid en -effektiwiteit, is vandag 'n noodsaaklikheid wat toenemend deur hedendaagse bedryfsleiers ondersteun en bestuur word. Binne die werksomgewing kom innovasie op drie verskillende vlakke (die individu, die groep en die organisasie) voor. Tot dusver het innovasienavorsers egter in hoofsaak op die individu en organisasie as ontledingseenheid gefokus. Navorsing wat die individu of organisasie as ontledingseenheid gebruik, is volop in vergelyking met studies wat die groep as ontledingseenheid gebruik. Met ander woorde, alhoewel die gebruikmaking van spanne in organisasies toeneem, is ons kennis van die faktore en dimensies wat spaninnoverendheid bepaal, steeds beperk. Die beperkte teoretiese basis van bestaande groepinnovasienavorsing kan deels aan die omvangryke en komplekse aard van die verskynsel toegeskryf word. Dit is juis in hierdie opsig dat hierdie studie dit ten doel gestel het om bestaande groepinnovasieliteratuur deeglik te ondersoek en om vas te stel tot watter mate verwante sosiaal-sielkundige navorsing (onder andere groepbesluitneming, intragroepkonflik en kreatiewe probleemoplossing) 'n bydrae tot die innovasieliteratuur kan lewer. Elk van die drie ontledingsvlakke (individu, groep, organisasie) het 'n unieke effek op die innoverendheid van 'n span, maar nie een van hierdie kategorieë verklaar uitsluitlik die innoverendheid van 'n span nie. Die interafhanklike verhouding van hierdie faktore beklemtoon die kompleksiteit van die verskynsel en dit moedig toekomstige navorsers aan om die nuttige bydraes van verwante sosiaal-sielkundige temas te ondersoek. In hierdie verband is daar ook breedvoerig gebruik gemaak van 'n inset, proses en uitset model van groepinnoverendheid deur West en Anderson (1996), ten einde vas te stel tot watter mate sekere aspekte van die model die innoverendheid van 'n span voorspel. Vanweë die omvangrykheid van die model is slegs sekere veranderlikes in die navorsing ingesluit. In terme van die insette is daar op grootte en spandienstydperk gefokus. Die proses faset van die model verwys na die duidelikheid en verbondenheid tot doelwitte, deelname, taakoriëntasie en ondersteuning vir innovasie. Ten opsigte van die uitset faset van die model is daar op die volgende aspekte gefokus: die radikaalheid, omvangrykheid, nuutheid en effektiwiteit van die innovasie asook die getal innovasie items binne die groep. Die resultate van die studie dui daarop dat daar wel 'n verband tussen hierdie veranderlikes van West en Anderson (1996) se model en die innoverendheid van groepe bestaan. Hierdie model van groepinnoverendheid blyk vanuit die resultate van hierdie studie, en vorige studies, nuttig te wees vir die bestudering van groepinnovasiegedrag. Alhoewel daar tot dusver min lig gewerp is op die faktore wat groepinnoverendheid bepaal, wil dit voorkom asof groepinnovasienavorsing 'n sentrale faset van die organisasiesielkunde se navorsingsagenda in die toekoms sal wees. Die vestiging en uitbreiding van 'n teoretiese basis salorganisasies in staat stelom die innovasiegedrag van spanne beter te verstaan en te voorspel. Ten slotte kan dit vermeld word dat hierdie studie In bydrae gelewer het tot groepinnovasiegedrag, nie net in terme van 'n bewusmaking van die impak en noodsaaklikheid van innovasie in die hedendaagse werksomgewing nie, maar ook in terme van die uitbreiding van die bestaande kennisbasis oor groepinnovasiegedrag.
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Franceschi, Paul. "Une Application Des N-Univers A L'argument De L'apocalypse Et Au Paradoxe De Goodman." Diss., University of Corsica, 2002. http://hdl.handle.net/10919/71552.
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Several philosophical problems are based on an analogy between a real situation and a probabilistic model. Such problems are based on urn analogies. The present dissertation aims to describe and implement a methodology oriented towards the resolution of philosophical problems based on an urn analogy. This methodology is based on the use of the n-universes. To this end, I describe first the n-universes in a detailed way. I also discuss the difficulties of the theory of n-universes related to the demultiplication of the criteria and to the relation one/many between the objects and a given criterion.On the one hand, I present an application of the framework of n-universes to the Doomsday argument and to the problems recently appeared in the literature in keeping with the Doomsday argument. My concern is also with showing how the application of the framework of n-universes to several problems and thought experiments related to the Doomsday argument helps clarifying the problem data and making disappear the associated ambiguity. I present then an analysis of the following problems related to the Doomsday argument: the two urn case, God's Coin Toss, the Sleeping Beauty Problem, the Presumptuous Philosopher, Lazy Adam, and the Shooting-Room Paradox. I present lastly a solution to the Doomsday argument, based on a third route, by contrast to two types of solutions classically described.On the other hand, I present an application of the framework of n-universes to Goodman's paradox. I replace first Goodman's statement in the framework of n-universes. I propose then a solution to the paradox, based on a distinction between two different modelizations of Goodman's statement in two structurally different n-universes.
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Huisamen, Petronella. "'n Evaluasie van die tydsbestuur, doelwitbeplanning en probleemoplossing kapasiteitsbouprogramme van die Suid-Afrikaanse Polisiediens / deur Petronella Huisamen." Thesis, North-West University, 2003. http://hdl.handle.net/10394/408.
Full textAbstract:
Background Due to the restructuring of the South African Police Service (SAPS) in 1996, as well as
other factors, Police Social Work Services decided to broaden the scope of its services to also include
pro-active, capacity building interventions. The result was the development of 15 personnel capacity
building programmes by 1999. The need arose for a comprehensive impact assessment of these
programmes and the Evaluation of Personnel Capacity Building Programmes (EPCBP) study was
subsequently launched in 2001. The evaluation of the Problem Solving, Planning of Goals and Time
Management Programmes formed part of this research.
Objectives: The primary aim of the study was to determine the effect of the Problem solving , Planning
of Goals and Time Management Programmes on SAPS personnel's knowledge, attitude and behaviour.
Method: In the research, the comparison group pre-test and post-test design and triangulation were used.
Fourteen measurement scales and a presenter's evaluation questionnaire were developed and utilized. It
involved 666 experimental group respondents, 132 comparison group members and 46 presenters.
Results: All three of the programmes had a significant effect on the respondents' knowledge, attitude
and behaviour and changed their personal and professional life in a very positive manner. The research
proved without doubt that the programmes are effective capacity-building tools in the hands of Police
Social Work Services. However there are still certain steps to be taken to further improve the
programmes.Thesis (M.A. (MW))--North-West University, Potchefstroom Campus, 2004.
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Fernandes, Antonio Carlos. "Sobre configurações centrais do problema de n-corpos. Configurações centrais planares, espaciais e empilhadas." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/45/45132/tde-04062012-103241/.
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No presente trabalho apresentaremos alguns aspectos do problema Newtoniano de n Corpos. Estudaremos o caso de dois corpos, que tem solução direta, embora não seja possível obter todas as variáveis como função do tempo. No caso n maior ou igual a 3 mostraremos que não existe método para integrar este problema via quadraturas. Podemos tirar apenas algumas informações sobre o caso geral, como a Identidade de Lagrange-Jacobi, o Teorema de Sundman-Weierstrass entre outros. Veremos alguns casos de soluções particulares, que serão chamadas de soluções homográficas. Nestas soluções a forma geométrica da configuração inicial dos corpos é preservada durante o movimento. Veremos condições necessárias sobre as configurações iniciais para que seja possível obter estas soluções. Mostraremos uma relação existente entre estas soluções particulares e os pontos críticos de uma aplicação, que associa a uma configuração a energia total e o momento angular total do sistema. Nestes vários casos, cairemos numa mesma equação algébrica, que será chamada de equação das configurações centrais. Mostraremos, em seguida, que as equações de configurações centrais são equivalentes a um outro conjunto de equações algébricas, que servem também para calcular as chamadas configurações centrais, porém, com estas equações as simetrias do problema ficam mais claras, às vezes. Faremos algumas aplicações diretas destas equações algébricas. Uma subclasse interessante da classe das configurações centrais são as chamadas de equações diferenciais empilhadas, nas quais um subconjunto próprio dos corpos também forma uma configuração central. Nos dois últimos capítulos veremos alguns exemplos de configurações centrais deste tipo, em especial aquelas onde podemos retirar uma massa e ainda ter uma configuração central.In this work we present some aspects of the Newtonian n--body problem. We study the case of two bodies, which have a straightforward solution, although we can not get all the variables as functions of the time. For n greater or equal to 3 we show that there is no method to integrate this problem by quadratures. We can have just some information about the general case, as the Lagrange-Jacobi\'s Identity the Sundman-Weierstrass\'s theorem and others. We will see some cases of particular solutions, which will be called homographic solutions. In these solutions the geometric shape of initial configuration of the bodies is preserved during the movement. We will see necessary conditions on the initial positions that turn possible to obtain these solutions. We show a relation between these particular solutions and critical points of an application, that associate the total energy and total angular momentum of the system. In these several cases, we will fall in same algebraic equation, which we called of the central configurations equations. We show that the central configurations equations are equivalent to another set of algebraic equations, which are also used to compute the central configurations, but with these equations the symmetries of the problem become clearer. We will make some direct applications these algebraic equations. An interesting subclass of the class of central configurations are called stacked differential equations, in which a proper subset of the bodies form a central configuration too. In the last two chapters we will see some examples of central configurations of this kind, especially those where we can remove a mass and still have a central configuration.
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Thibaut, Jérôme. "Corrélations, intrication et dynamique des systèmes quantiques à N Corps : une étude variationnelle." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEN021/document.
Full textAbstract:
Cette thèse porte sur l'étude de systèmes quantiques à N-corps à température nulle, où le comportement du système n'est alors soumis qu'aux effets quantiques. Je vais présenter ici une approche variationnelle développée avec Tommaso Roscilde, mon directeur de thèse, et Fabio Mezzacapo, mon co-encadrant de thèse, pour étudier ces systèmes.Cette approche se base sur une parametrisation de l’état quantique (dit Ansatz) à laquelle on applique une procédure d’optimisation variationnelle lui permettant de reproduire l'évolution d'un système soumis à l'équation de Schrödinger, tout en limitant le nombre de variables considérées. En considérant une évolution en temps imaginaire, il est possible d'étudier l'état fondamental d'un système. Je me suis ainsi intéressé à un modèle de chaîne XX de spins 1/2, dont les corrélations à longue portée rendent l'étude difficile, et adapté ainsi notre approche pour reproduire au mieux les corrélations et l'intrication du système. Je me suis ensuite intéressé au modèle J1-J2 dont la structure de signe non positive des coefficients de l’état quantique pose un défi important pour les approches Monte Carlo; et dans laquelle la frustration magnétique induit une transition de phase quantique (d’un état aux corrélations à longue porté vers un état non magnétique avec formation d’un cristal de lien de valence). Je me suis enfin intéressé à l'évolution temporelle d'un système à N-corps à partir d'un état non stationnaire. J'ai pu étudier la capacité de notre approche à reproduire la croissance linéaire de l’intrication dans le temps, ce qui est un obstacle fondamental pour les approches alternatives telles que le groupe de renormalisation de la matrice densitéThis thesis presents a study of quantum many-body systems at zero temperature, where the behavior of the system is purely driven by the quantum effects. I will introduce a variationnal approach developped with Tommaso Roscilde, my PhD supervisor, and Fabio Mezzacapo, my co-supervisor, in order to study these systems.This approach is based on a parametrisation of the quantum state (named Ansatz) on which we apply a variational optimisation, allowing us reproduce the system's evolution under Schrödinger's equation with a limited number of variables.By considering an imaginary-time evolution, it is possible to reconstruct the system's ground state. I focused on S=1/2 XX spin chain, where the long-range quantum correlations complicate a variational study; and I have specifically targeted our Ansatz in order to reproduce the correlations and the entanglement of the ground state. Moreover I considered the antiferromagnetic S=1/2 J1-J2 spin chain, where the non-trivial sign structure of the coefficients of the quantum state introduces an important challenge for the quantum Monte Carlo approach; and where the magnetic frustration induces a quantum phase transition (from a state with long range correlations to a non-magnetic state in the form of a valence-bond crystal).Finally I focused on the time evolution of a quantum many-body system starting from a non-stationary state. I studied the ability of our approach to reproduce the linear increase of the entanglement during time, which is a fondamental obstacle for other approaches such as the density-matrix renormalization group
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Hjerpe, Daniel. "A study on SSE optimisation regarding initialisation and evaluation of the Fast Multipole Method." Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-298122.
Full textAbstract:
The following study examines whether the initialisation (multipole expansions at the finest level) and evaluation of the numerical method Fast Multipole Method (FMM) can benefit from implementing SSE instructions. The implementation of SSE-instructions have been studied and compared to the serial case. Moreover, studied parts of the algorithm include arithmetics on complex numbers, and the usage of applying SSE instructions to complex numbers of double precision. In conclusion, the initialisation has not experienced any improvement in terms of throughput by appliying SSE instructions. However, the evaluation reached almost the double speed-up when SSE instructions were applied. The difference in results are most likely due to the structure of the both algorithms. The initialisation is simple, but the evaluation which involves more operations can benefit from SSE instructions. Furthermore, a scheme is proposed for how SSE instructions can be applied to data sets which are not divisable by the unroll factor and to data sets of varying size.
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Лютий, Тарас Володимирович, Тарас Владимирович Лютый, Taras Volodymyrovych Liutyi, Олександр Юрійович Поляков, Александр Юрьевич Поляков, Oleksandr Yuriiovych Poliakov, S. Denisov, and P. Hanggi. "Technique of the Fast Ferrofluids Simulation." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35341.
Full textAbstract:
We present a highly-parallel implementation of the Langevin simulation method for modeling ferrofluids
on Graphical Processor Units (GPU). Our method is based on the Barnes-Hut algorithm. As a benchmark
we use the straightforward 'all-to-all interaction' algorithm. The obtained results are in good agreement
with known theoretical model. With the proposed method we were able to follow the evolution of a
system of one million interacting particles over long time-scales, the task hitherto is out of reach with the
standard, CPU-based numerical schemes.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35341
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Breed, Elizabeth Alice. "'n Analise van die reflektiewe vermoëns van effektiewe en oneffektiewe leerders in rekenaarprogrammering / Elizabeth Alice Breed." Thesis, North-West University, 2006. http://hdl.handle.net/10394/13.
Full textAbstract:
As a result of the interactive nature of modern programming languages the perception has
developed that proper planning of a solution, reasoned action during the process of problem
solving and evaluation of the solution have become less important during computer
programming. Learn often rely on the programming language to help them solve a problem,
without themselves planning the solution beforehand and then using a computer language to
implement the solution. This approach usually leads to using bad programming techniques,
resulting in unstructured programmes or rendering the learner unable to solve the problem.
The importance of continuous reflection by learners while doing a programming activity has
been advocated for quite some time...Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2006.
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Larsson, Andreas [Verfasser]. "Gogol' und das Problem der menschlichen Identität : Die "Petersburger Erzählungen" und der "Revisor" als Beispiele für ein grundlegendes Thema in den Werken von N. V. Gogol'. / Andreas Larsson." Frankfurt a.M. : Peter Lang GmbH, Internationaler Verlag der Wissenschaften, 1992. http://d-nb.info/1165480972/34.
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Pires, Matheus Giovanni. "Abordagem neuro-genética para mapeamento de problemas de conexão em otimização combinatória." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18153/tde-12062009-150911/.
Full textAbstract:
Devido a restrições de aplicabilidade presentes nos algoritmos para a solução de problemas de otimização combinatória, os sistemas baseados em redes neurais artificiais e algoritmos genéticos oferecem um método alternativo para solucionar tais problemas eficientemente. Os algoritmos genéticos devem a sua popularidade à possibilidade de percorrer espaços de busca não-lineares e extensos. Já as redes neurais artificiais possuem altas taxas de processamento por utilizarem um número elevado de elementos processadores simples com alta conectividade entre si. Complementarmente, redes neurais com conexões realimentadas fornecem um modelo computacional capaz de resolver vários tipos de problemas de otimização, os quais consistem, geralmente, da otimização de uma função objetivo que pode estar sujeita ou não a um conjunto de restrições. Esta tese apresenta uma abordagem inovadora para resolver problemas de conexão em otimização combinatória utilizando uma arquitetura neuro-genética. Mais especificamente, uma rede neural de Hopfield modificada é associada a um algoritmo genético visando garantir a convergência da rede em direção aos pontos de equilíbrio factíveis que representam as soluções para os problemas de otimização combinatória.Due to applicability constraints involved with the algorithms for solving combinatorial optimization problems, systems based on artificial neural networks and genetic algorithms are alternative methods for solving these problems in an efficient way. The genetic algorithms must its popularity to make possible cover nonlinear and extensive search spaces. On the other hand, artificial neural networks have high processing rates due to the use of a massive number of simple processing elements and the high degree of connectivity between these elements. Additionally, neural networks with feedback connections provide a computing model capable of solving a large class of optimization problems, which refer to optimization of an objective function that can be subject to constraints. This thesis presents a novel approach for solving connection problems in combinatorial optimization using a neurogenetic approach. More specifically, a modified Hopfield neural network is associated with a genetic algorithm in order to guarantee the convergence of the network to the equilibrium points, which represent feasible solutions for the combinatorial optimization problems.
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Du, Plessis Linda Alida. "'n Onderrigmodel vir die aanwending van tegnologie by die implementering van aksieleer in die vak inligtingstelsels / Linda Alida du Plessis." Thesis, Potchefstroom University for Christian Higher Education, 2002. http://hdl.handle.net/10394/9095.
Full textAbstract:
In this study, the integration of technology in education and the application of action learning as a teaching strategy, are investigated through a literature study and with empirical research. The purpose is to develop a teaching model wherein technology can be effectively incorporated for the offering of the subject Information Systems (IS). The study also focuses on the nature and scope of the subject Information Systems, as well as the status concerning the subject Information Systems at Technikons in South Africa. Knowledge regarding technology quickly becomes obsolete and therefore IS-learners should have the means and skills to keep abreast of advances in technology. IS-learners not only need subject oriented knowledge, but also personal skills that are known as critical cross field outcomes in the new educational paradigm. The establishment of the National Qualification framework, led to an academic initiative that is based on transparent national standards and clear descriptions of learning outcomes. For higher education institutions in South Africa the implication was that all curricula of subjects, including Information Systems, had to be rewritten in terms of outcomes. Specialisation is essential for the Information System qualification, as it became apparent that information system applications and demands from industry are becoming specialised. In 1999 the IS-qualification was adjusted to provide for specialisation areas at Technikons in South Africa. Action learning integrates the theories and characteristics of several disciplines, amongst others, education, psychology, systems thinking, political science, ethics, anthropology and sociology. During the process of action learning, knowledge must be constructed by asking questions, processing information and applying the newly acquired knowledge. Links must be established between new knowledge and pre-knowledge. Action learning attempts to integrate the elements of
knowledge, insight and practice, and states that there can be no learning without action and that no purposeful action can take place without learning, while the solving of a problem influences both the problem and the person that acts on the problem. Action learning satisfies all the requirements needed to address the knowledge, values, skills and behaviour that IS-learners should adhere to. Action learning stimulates the development of cognitive skills that are essential for the training ofiS-learners. The different types of information systems that are found in organisations are not isolated systems, but rather integrated systems that collaborate in order to support a business function. IS-learners should not only understand the development, but also the integration and implementation of these systems. From this it becomes apparent that action learning is a suitable teaching strategy for IS-learners. The classification of educational technology as well as a framework for the implementation thereof, is discussed in the study. According to the literature study and from results obtained from the empirical research, a teaching model is proposed that consists of the following three components: • Determinants that influence the teaching and learning scenario. These determinants include the National Qualification framework industry; technology infrastructure; institutional policy and outcomes based education. • The didactic triangle, in which the distinct roles of the learners (that can act as facilitators during action learning) and educators are discussed, as well as the outcomes for the subject Information Systems. • Action learning and the utilisation of technology as the teaching strategy within the proposed model. The proposed action learning and technology teaching model promotes a learner-centred approach and focuses on learning outcomes, rather than learning contents. The proposed model empowers learners as well as educators and makes provision for the use of technology within the financial constraints of institutions.Thesis (Ph.D. (Education))--Potchefstroom University for Christian Higher Education, 2003