1,721,261 research outputs found
A time-based decomposition algorithm for fast simulation with mathematical programming models
No full textMathematical programming has been proposed in the literature as an alternative technique to simulate a special class of Discrete Event Systems. Several are the benefits of using a mathematical programming model for simulating but the non–linear computational time (in the number of simulated entities) needed for the solution of the models can be a huge barrier to its use in long simulations. This paper proposes a time–based decomposition algorithm that splits the mathematical programming model into a number of submodels to be solved sequentially so as to exploit the super–additivity of many non–linear functions and make the mathematical programming approach viable also for long run simulations. The number of
needed submodels is the solution of an optimization problem that minimizes the expected time to solve all the submodels. The main result is that in this way the solution time becomes a linear function of the number of simulated entities
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Structure of Arabidopsis thaliana GLR3.3 ligand-binding domain in complex with L-methionine
No full textMathematical programming formulation for approximate simulation of closed-loop systems
No full textClosed-loops systems have been analyzed by means of Markov theory, discrete event simulation models, renewal theory and random walks. The dynamics of discrete event systems (DES) has been recently addressed with the mathematical programming technique. In particular, DESs are mapped into a mixed integer linear programming (MILP) formulation, the optimal solution of which represents the trajectory of the DES itself, i.e., the output of a standard simulation. This paper proposes approximate linear programming–based models to simulate and optimize the closed–loop system behavior. The approximation has been obtained by relaxing the constraints that keep the number of parts circulating in the system constant. In the relaxed model,
the fixed population aspect, which characterizes the system, is indirectly modeled by means of continuous time variables that limit the entering (leaving) of parts into (from) the system. The main advantage of the proposed approximate simulation model is that it preserves its linearity even when used for optimization.
Numerical experiments show the accuracy of the proposed models for the optimal pallet allocation problem
Structure of Arabidopsis thaliana GLR3.3 ligand-binding domain in complex with L-glutamate
No full textStructure of Arabidopsis thaliana GLR3.3 ligand-binding domain in complex with L-cysteine
No full textEndoscopic endonasal transsphenoidal approach to the sella: Towards functional endoscopic pituitary surgery (FEPS)
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