Decentralized Blocking Zeros and the Decentralized Strong Stabilization Problem

This paper is concerned with a new system theoretic concept, decentralized blocking zeros, and its applications in the design of decentralized controllers for linear time-invariant finite-dimensional systems. The concept of decentralized blocking zeros is a generalization of its centralized counterpart to multichannel systems under decentralized control. Decentralized blocking zeros are defined as the common blocking zeros of the main diagonal transfer matrices and various complementary transfer matrices of a given plant. As an application of this concept, we consider the decentralized strong stabilization problem (DSSP) where the objective is to stabilize a plant using a stable decentralized controller. It is shown that a parity interlacing property should be satisfied among the real unstable poles and real unstable decentralized blocking zeros of the plant for the DSSP to be solvable. That parity interlacing property is also sufficient for the solution of the DSSP for a large class of plants satisfying a certain connectivity condition. The DSSP is exploited in the solution of a special decentralized simultaneous stabilization problem, called the decentralized concurrent stabilization problem (DCSP). Various applications of the DCSP in the design of controllers for large-scale systems are also discussed. © 1995 IEE

Contesting longstanding conceptualisations of urban green space

Ever since the Victorian era saw the creation of “parks for the people,” health and wellbeing benefits have been considered a primary benefit of urban parks and green spaces. Today, public health remains a policy priority, with illnesses and conditions such as diabetes, obesity and depression a mounting concern, notably in increasingly urbanised environments. Urban green space often is portrayed as a nature-based solution for addressing such health concerns. In this chapter, Meredith Whitten investigates how the health and wellbeing benefits these spaces provide are limited by a narrow perspective of urban green space. Whitten explores how our understandings of urban green space remain rooted in Victorian ideals and calls into question how fit for purpose they are in twenty-first-century cities. Calling on empirical evidence collected in three boroughs in London with changing and increasing demographic populations, she challenges the long-held cultural underpinnings that lead to urban green space being portrayed “as a panacea to urban problems, yet treating it as a ‘cosmetic afterthought’” (Whitten, M, Reconceptualising green space: planning for urban green space in the contemporary city. Doctoral thesis, London School of Economics and Political Science, London, U.K. http://etheses.lse.ac.uk/. Accessed 12 Jun 2019, 2019b, p 18)

OPTIMAL SUBCUBE ALLOCATION IN A CIRCUIT-SWITCHED FAULTY HYPERCUBE

In this paper, we present a scheme where a (d;1)-dimensional subcube is allocated in a faulty d-dimensional circuit-switched hypercube in the presence of up to 2 (d;1) faulty nodes. The scheme is then extended to allocate a (d; 1)-dimensional subcube in the presence of a combination of faulty nodes and faulty links. Theoretical proofs and simulation results are presented to analyze the performance of the scheme

Enhanced Cluster k-Ary n-Cube, A Fault-Tolerant Multiprocessor

Abstract—In this paper, we present a strongly fault-tolerant design for the k-ary n-cube multiprocessor and examine its reconfigurability. Our design augments the k-ary n-cube with ðk jÞn spare nodes. Each set of jn regular nodes is connected to a spare node and the spare nodes are interconnected as either a ðk k k jÞ-ary n-cube if j 6 2 or a hypercube of dimension n if j 2. Our approach utilizes the capabilities of the wave-switching communication modules of the spare nodes to tolerate a large number of faulty nodes. Both theoretical and experimental results are examined. Compared with other proposed schemes, our approach can tolerate significantly more faulty nodes with a low overhead and no performance degradation