Robust stability conditions for feedback interconnections of distributed-parameter negative imaginary systems

Sufficient and necessary conditions for the stability of positive feedback interconnections of negative imaginary systems are derived via an integral quadratic constraint (IQC) approach. The IQC framework accommodates distributed-parameter systems with irrational transfer function representations, while generalising existing results in the literature and allowing exploitation of flexibility at zero and infinite frequencies to reduce conservatism in the analysis. The main results manifest the important property that the negative imaginariness of systems gives rise to a certain form of IQCs on positive frequencies that are bounded away from zero and infinity. Two additional sets of IQCs on the DC and instantaneous gains of the systems are shown to be sufficient and necessary for closed-loop stability along a homotopy of systems.Comment: Submitted to Automatica, A preliminary version of this paper appeared in the Proceedings of the 2015 European Control Conferenc

Applications and Experiences of Quality Control

The rich palette of topics set out in this book provides a sufficiently broad overview of the developments in the field of quality control. By providing detailed information on various aspects of quality control, this book can serve as a basis for starting interdisciplinary cooperation, which has increasingly become an integral part of scientific and applied research

Robust ℋ∞ consensus for multi-agent systems with time-varying input delay using dynamic IQCs

In this paper, the distributed consensus control problem for linear multi-agent systems, subject to external disturbance and time-varying input delays, is addressed under the robust ℋ∞ and dynamic integral quadratic constraint (IQC) analysis framework. A novel distributed protocol is proposed using both relative plant state and IQC dynamics state information. It is shown that under the proposed design scheme, the consensus performance can be reached by solving the ℋ∞ control problems for a set of independent linear fractional transformation (LFT) systems, whose dimensions are equal to that of a single agent plant plus a single IQC dynamics. Furthermore, the synthesis conditions for the proposed IQC-based distributed consensus control are formulated in terms of linear matrix inequalities (LMIs), such that the optimal ℋ∞ consensus protocol can be synthesized via convex optimization. A numerical example is used to demonstrate the effectiveness of the proposed approach

Private food law: Governing food chains through contract law, self-regulation, private standards, audits and certification schemes

Since the turn of the Millennium, world-wide initiatives from the private sector have turned the regulatory environment for food businesses upside down. For the first time in legal literature this book analyses private law initiatives relating to the food chain, often referred to as private (voluntary) standards or schemes. Private standards are used to remedy flaws in legislation in order to reach higher levels of consumer protection than the ones chosen by the EU legislature and to manage risks and liability beyond the traditional limits of food businesses. We see that litigation is no longer solely framed by legislative requirements, but ever more by private standards such as GlobalGAP, BRC, IFS, SQF and ISO. These private standards incorporate public law requirements thus embedding them in contractual relations and exporting them beyond the jurisdiction of public legislators. This book also addresses how private standards play a role in defining specific markets of growing importance. It is noted that organic standards have found an interesting symbioses with public law. Another development on this topic is that food businesses are inspected more often by private auditors than by public inspectors. Effects in terms of receiving or being denied certification far outweigh public law sanctions. In short private law has changed an entire legal infrastructure for the food sector. It emerges as competing with the public law regulatory infrastructure. This book is of interest to all who concern themselves with food law legislation and litigation and the evolving role of private standards on changing the landscape of food chains and innovation