22,902 research outputs found
Social Union, Migration and the Constitution: Integration at Risk
Europäische Integration, Mobilität, Soziale Integration, Sozialstaat, Europäische Wirtschafts- und Währungsunion, European integration, Mobility, Social integration, Welfare state, European Economic and Monetary Union
Supervisor Localization of Discrete-Event Systems based on State Tree Structures
Recently we developed supervisor localization, a top-down approach to
distributed control of discrete-event systems in the Ramadge-Wonham supervisory
control framework. Its essence is the decomposition of monolithic (global)
control action into local control strategies for the individual agents. In this
paper, we establish a counterpart supervisor localization theory in the
framework of State Tree Structures, known to be efficient for control design of
very large systems. In the new framework, we introduce the new concepts of
local state tracker, local control function, and state-based local-global
control equivalence. As before, we prove that the collective localized control
behavior is identical to the monolithic optimal (i.e. maximally permissive) and
nonblocking controlled behavior. In addition, we propose a new and more
efficient localization algorithm which exploits BDD computation. Finally we
demonstrate our localization approach on a model for a complex semiconductor
manufacturing system
Majorana fermion exchange in strictly one dimensional structures
It is generally thought that adiabatic exchange of two identical particles is
impossible in one spatial dimension. Here we describe a simple protocol that
permits adiabatic exchange of two Majorana fermions in a one-dimensional
topological superconductor wire. The exchange relies on the concept of
"Majorana shuttle" whereby a domain wall in the superconducting order
parameter which hosts a pair of ancillary Majoranas delivers one zero mode
across the wire while the other one tunnels in the opposite direction. The
method requires some tuning of parameters and does not, therefore, enjoy the
full topological protection. The resulting exchange statistics, however,
remains non-Abelian for a wide range of parameters that characterize the
exchange.Comment: 5 pages, 4 figures, supplemental material is include
Claudins in the Renal Collecting Duct
The renal collecting duct fine-tunes urinary composition, and thereby, coordinates key physiological processes, such as volume/blood pressure regulation, electrolyte-free water reabsorption, and acid-base homeostasis. The collecting duct epithelium is comprised of a tight epithelial barrier resulting in a strict separation of intraluminal urine and the interstitium. Tight junctions are key players in enforcing this barrier and in regulating paracellular transport of solutes across the epithelium. The features of tight junctions across different epithelia are strongly determined by their molecular composition. Claudins are particularly important structural components of tight junctions because they confer barrier and transport properties. In the collecting duct, a specific set of claudins (Cldn-3, Cldn-4, Cldn-7, Cldn-8) is expressed, and each of these claudins has been implicated in mediating aspects of the specific properties of its tight junction. The functional disruption of individual claudins or of the overall barrier function results in defects of blood pressure and water homeostasis. In this concise review, we provide an overview of the current knowledge on the role of the collecting duct epithelial barrier and of claudins in collecting duct function and pathophysiology
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