Second-order scalar-tensor field theories

Download
2017
Şahin, Ertan Sinan
We review Horndeski’s scalar-tensor theory in this thesis. Partial differential equations that are satisfied by the Lagrangian limit its most general form. Demanding second-order field equations both for the metric and the scalar field, and choosing a four-dimensional spacetime also put restrictions on the most general form of the Lagrangian. Besides, by using similar techniques, in a four-dimensional spacetime, we find the most general form of the second-order Euler-Lagrange equations that are obtained from the Lagrangian through a variation of the metric. Finally, making use of relations between field equations and the Lagrangian, the most general form of the Lagrangian is obtained. Thus, one establishes the most general scalar-tensor theory in a four-dimensional spacetime.  

Suggestions

Radar performance analysis approaches for the evaluation of radar systems
Yener, Ümit; Kuzuoğlu, Mustafa; Department of Electrical and Electronics Engineering (2018)
In this thesis study, some approaches are proposed for radar performance analysis. It turns out that average power and antenna aperture area (equivalently, antenna gain) are the most important parameters for the assessment or comparison of radar systems. Search and track load concepts and the utilization trade between search and tracking tasks in multifunction radars are also presented. For long distance search / tracking tasks, performance of a two-radar system is analyzed, and it is shown that cross range...
Applied supervisory control for a flexible manufacturing system
Moor, Thomas; Schmidt, Klaus Verner; Perk, Sebastian (2010-12-01)
This paper presents a case study in the design and implementation of a discrete event system (DES) of real-world complexity. Our DES plant is a flexible manufacturing system (FMS) laboratory model that consists of 29 interacting components and is controlled via 107 digital signals. Regarding controller design, we apply a hierarchical and decentralised synthesis method from earlier work in order to achieve nonblocking and safe closed-loop behaviour. Regarding implementation, we discuss how digital signals tr...
A marginalized multilevel model for bivariate longitudinal binary data
İnan, Gül; İlk Dağ, Özlem; Department of Statistics (2014)
This thesis study considers analysis of bivariate longitudinal binary data. We propose a model based on marginalized multilevel model framework. The proposed model consists of two levels such that the first level associates the marginal mean of responses with covariates through a logistic regression model and the second level includes subject/time specific random intercepts within a probit regression model. The covariance matrix of multiple correlated time-specific random intercepts for each subject is assu...
TEACHERS THEORETICAL ORIENTATIONS TOWARD TEACHING THINKING
Yıldırım, Ali (Informa UK Limited, 1994-09-01)
The literature on teaching thinking reflects a major controversy that results from two distinctive theoretical views about the nature of thinking. One focuses on content of thinking, and the other emphasizes skills involved in thinking. However, an attempt to understand practitioners' perceptions of these theories is generally absent in the literature. The purpose of this study was to investigate teachers' theoretical orientations toward teaching thinking, using a survey questionnaire. Ths sample includ...
Institutional imperatives versus emergent dynamics: a case study on continuous change in higher education
Kondakçı, Yaşar (Springer Science and Business Media LLC, 2009-10-01)
This qualitative case study examines continuous change in a higher education organization (HEO). Both real time and retrospective data covering a 6-year period of the case were collected. The findings suggest that, in order to meet institutional imperatives the HEO defined several managerial and academic domains when the internationalization process was launched. When organizational members activate these domains they confronted with local needs, problems, and opportunities, which enable them to modify, upd...
Citation Formats
E. S. Şahin, “Second-order scalar-tensor field theories,” M.S. - Master of Science, Middle East Technical University, 2017.