Scalable robustness of interconnected systems subject to structural changes

This paper studies the robustness of large-scale interconnected systems with respect to external disturbances, focussing on their scalability properties. Specifically, a notion of scalability is introduced that asks for these robustness properties to remain unchanged under a structural change of the system, such as the addition/removal of a subsystem or a change in the interconnection structure. Both necessary and sufficient conditions, in terms of the interconnection structure and edge weights, are given under which elementary structural changes are scalable. The results are illustrated through a simple example.Comment: Published in the Proceedings of the IFAC World Congress, Berlin, Germany, 202

Adaptive Kalman filtering for anomaly detection in software appliances

Availability and reliability are often important features of key software appliances such as firewalls, web servers, etc. In this paper we seek to go beyond the simple heartbeat monitoring that is widely used for failover control. We do this by integrating more fine grained measurements that are readily available on most platforms to detect possible faults or the onset of failures. In particular, we evaluate the use of adaptive Kalman Filtering for automated CPU usage prediction that is then used to detect abnormal behaviour. Examples from experimental tests are given

Metal-Isonitriles - Synthesis, characterization and application in catalysis

After a short introduction on the history of isonitriles, chapter A describes the preparation of oxazole-derived isonitriles. Based upon previous investigations in our group, bis(2-isocyanophenyl)phenylphosphonate (binc) could be prepared by the metalation of benzoxazole followed by subsequent trapping of the resulting anion with phenylphosphonic dichloride. Further the solid-state structure of this ligand and its PdCl2-complex was investigated. Chapter B gives an overview on the molecular structure and catalytic activity of various isonitrile complexes of the Cr, Mn, Fe, Co, Ni and Cu triads that were, so far, successfully applied in metal catalysis. In Chapter C, the synthesis of a series of heteroleptic [Cu(phenantroline)(bisisonitrile)]+-complexes and the investigation of their structural, spectroscopic and electrochemical properties is described. The new copper(I) complexes were employed as photoredox-catalysts in the visible light-mediated atom transfer radical addition (ATRA). Especially [Cu(dpp)(binc)]BF4 (dpp = 2,9-diphenyl-1,10-phenanthroline) proved to be highly active owing to an enhanced excited state lifetime compared to the commonly employed [Cu(dap)2]Cl (dap = 2,9-di(p-anisyl)-1,10-phenanthroline). Furthermore, the catalyst could be applied to allylation reactions with trimethylallylsilane under mild visible-light photoredox conditions. In Chapter D, the preparation of two new chiral bidentate isonitrile-diaminocarbene palladium(II) complexes as well as one bis-diaminocarbene complex by metal-mediated nucleophilic addition of amines to the corresponding bisisonitrile-palladium(II) compound is described. The new chelates were fully characterized by 1D- and 2D-NMR experiments, IR, ESI-MS and X-ray structure analysis. Showing different sterical properties we furthermore investigated the relationship between their structure and their catalytic activity. The mixed ligand complexes showed both excellent activity in Suzuki-Miyaura cross coupling and the intermolecular asymmetric allylic alkylation (AAA) as well as moderate chiral induction in the AAA. In addition, the synthesis of a chiral bidentate isonitrile/N-heterocyclic carbene-palladium(II) complex is described. Chapter E finally, covers the preparation and structural discussion of a full matrix of twelve platinum(II) complexes of the structure Pt(biphenyl)(isonitrile)n (n = 1,2) derived from their corresponding Pt(biphenyl)(CO)2-precursors. The modifications were introduced by the combination of three different 2,2’-biphenyls with four different isonitrile ligands. In addition, a first evaluation of their emission properties was performed

Applications of Linear Co-positive Lyapunov Functions for Switched Linear Positive Systems

In this paper we review necessary and sufficient conditions for the existence of a common linear co-positive Lyapunov function for switched linear positive systems. Both the state dependent and arbitrary switching cases are considered and a number of applications are presented

Nachruf auf Dr. Harro Heim (1919–2016). Direktor der Universitätsbibliothek Bielefeld 1968–1984: Leidenschaft für Bielefeld

Knorn B. Nachruf auf Dr. Harro Heim (1919–2016). Direktor der Universitätsbibliothek Bielefeld 1968–1984: Leidenschaft für Bielefeld. O-Bib. Das Offene Bibliotheksjournal. 2016;3(4):347-349

A Result On Implicit Consensus with Application to Emissions Control

This paper is concerned with a class of decentralised control problems that arise in contemporary applications where agents cooperate to control and regulate a global quantity, are limited in the manner in which they communicate with each other, and are required to reach consensus on some implicit variable (for instance, CO2 emissions). An algorithm is presented for achieving this goal. A simplified application of the algorithm to emissions control for a fleet of Plug-in Hybrid Electric Vehicles (PHEVs) is given