1,720,958 research outputs found
General approach for solving optimal control problems using optimization techniques
No full textA general approach to the determination of approximate solutions of general control problems by exploiting modern global search and optimization techniques is proposed. According to the methodology developed in this paper, controls are represented by discrete vectors and substituted in system equations. The components of these vectors are regarded as variables of a performance index based goal function that is to be minimized with respect to the system constraints. Such an approach enables modeling and solution of a wide class of optimal control problems, arising in engineering practice, within a unified framework of constrained optimization techniques, including implementation of genetic algorithms for global optimization and multiobjective control. Computer realizations of the proposed method are mainly based on MATLAB simulation programs. The results obtained can be implemented to solve optimal control problems in the field of Computer Aided Control Engineering, Computer Integrated Manufacturing, Mechatronics and Robotics
H∞ design of an EMS control system for a maglev vehicle using evolutionary algorithms
No full textAn evolutionary algorithm approach is proposed for the H∞ design of an EMS control system for a maglev vehicle. The algorithm is used in conjunction with an H∞ loop-shaping design procedure to search over a space of possible weighting function structures and parameter values in order to satisfy a number of conflicting design criteria
Evolutionary H_inf design of an electromagnetic suspension control system for a maglev vehicle
No full textA multiobjective evolutionary algorithm approach is proposed for the H? design of an electromagnetic suspension (EMS) control system for a maglev vehicle. The evolutionary algorithm is used in conjunction with an H? loop-shaping design procedure to perform multiobjective search over a set of possible weighting function structures and parameter values in order to satisfy a number of conflicting design criteria. It is demonstrated that the proposed approach offers a number of potential benefits over other 'mixed optimization' techniques by allowing the control engineer to select from a number of satisfactory design solutions of differing complexity
Multiobjective robust control using evolutionary algorithms
No full textAn evolutionary algorithm approach is proposed for the robust design of control systems. The evolutionary algorithm is used in conjunction with an H∞ loop-shaping design procedure to perform multiobjective search over a set of possible weighting function structures and parameter values in order to satisfy a number of conflicting design criteria. An example of an EMS control system for a critical system, a magnetically levitated passenger transport vehicle, is used to demonstrate the proposed approach
Approach for path following optimal control of multibody systems
No full textAn approach is proposed to the determination of approximate solutions of path following optimal control problems by exploiting modern global search and optimization techniques. An optimal path following algorithm for control of multibody systems is developed and a test example for minimum-time-energy control of a two-link manipulator is presented. Computer realization of the proposed method is mainly based on MATLAB simulation programs for function approximation, constrained optimization and genetic algorithms. The results of the method can be implemented to solve path following optimal control problems in the field of Computer Aided Control Engineering, Computer Integrated Manufacturing, Mechatronics and Robotics
Adaptive active vibration control using genetic algorithms
No full textThe development of an adaptive active control mechanism for vibration suppression using genetic algorithms is investigated. Active vibration control consists of artificially generating cancelling source to destructively interfere with the unwanted source and thus result in a reduction in the level of the vibration disturbance at desired locations. A supervisory level control has been incorporated within the algorithm which allows on-line monitoring of system performance and controller adaptation
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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