423 research outputs found
Bond graph based control and substructuring
A bond graph framework giving a unified treatment of both physical-model based control and hybrid experimentalânumerical simulation (also known as real-time dynamic substructuring) is presented. The framework consists of two subsystems, one physical and one numerical, connected by a transfer system representing non-ideal actuators and sensors. Within this context, a two-stage design procedure is proposed: firstly, design and/or analysis of the numerical and physical subsystem interconnection as if the transfer system were not present; and secondly removal of as much as possible of the transfer system dynamics while having regard for the stability margins established in the first stage. The approach allows the use of engineering insight backed up by well-established control theory; a number of possibilities for each stage are given.
The approach is illustrated using two laboratory systems: an experimental mass-spring-damper substructured system and swing up and hold control of an inverted pendulum. Experimental results are provided in the latter case
Identity and integration of Russian speakers in the Baltic states: a framework for analysis
Following a review of current scholarship on identity and integration patterns of Russian speakers in the Baltic states, this article proposes an analytical framework to help understand current trends. Rogers Brubaker's widely employed triadic nexus is expanded to demonstrate why a form of Russian-speaking identity has been emerging, but has failed to become fully consolidated, and why significant integration has occurred structurally but not identificationally. By enumerating the subfields of political, economic, and cultural âstancesâ and ârepresentationsâ the model helps to understand the complicated integration processes of minority groups that possess complex relationships with âexternal homelandsâ, ânationalizing statesâ and âinternational organizationsâ. Ultimately, it is argued that socio-economic factors largely reduce the capacity for a consolidated identity; political factors have a moderate tendency to reduce this capacity, whereas cultural factors generally increase the potential for a consolidated group identity
Revisit of the Interaction between Holographic Dark Energy and Dark Matter
In this paper we investigate the possible direct, non-gravitational
interaction between holographic dark energy (HDE) and dark matter. Firstly, we
start with two simple models with the interaction terms
and , and then we move on to the general form . The cosmological constraints of the models are
obtained from the joint analysis of the present Union2.1+BAO+CMB+ data. We
find that the data slightly favor an energy flow from dark matter to dark
energy, although the original HDE model still lies in the 95.4% confidence
level (CL) region. For all models we find at the 95.4% CL. We show that
compared with the cosmic expansion, the effect of interaction on the evolution
of and is smaller, and the relative increment
(decrement) amount of the energy in the dark matter component is constrained to
be less than 9% (15%) at the 95.4% CL. By introducing the interaction, we find
that even when the big rip still can be avoided due to the existence of a
de Sitter solution at . We show that this solution can not be
accomplished in the two simple models, while for the general model such a
solution can be achieved with a large , and the big rip may be avoided
at the 95.4% CL.Comment: 26 pages, 9 figures, version accepted for publication in JCA
The Structure of Interpretations in Family Therapy: A Video-Enhanced Exploration *
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73991/1/j.1545-5300.2000.39204.x.pd
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