Agency working in Britain: character, consequences and regulation

Debate over the nature of temporary agency work has intensified in recent times, spurred on by a proposed European directive and by speculation about links with the much heralded ‘knowledge’ economy. This paper examines the debate, focusing on the current character of agency work in Britain. Using data from the Labour Force Survey, we assess some of the claims commonly made about agency work, relating to the personal and employment characteristics of those engaged in such work, the motives of agency workers and the prospects for those who take up agency jobs. In considering the arguments surrounding regulatory change, we find there is a strong case for regulation, but that this rests on the continued disadvantage associated with agency work, with little evidence of an impact from the purported ‘knowledge’ economy.

Active versus passive damping in large flexible structures

Optimal passive and active damping control can be considered in the context of a general control/structure optimization problem. Using a mean square output response approach, it is shown that the weight sensitivity of the active and passive controllers can be used to determine an optimal mix of active and passive elements in a flexible structure

Hearing Earth’s Cry: Rhetoric and Reality in Integral Ecology

Die Metapher „Schrei der Erde“ gewinnt in der Rhetorik der integralen Ökologie zunehmend an Bedeutung. In vorliegendem Beitrag wird argumentiert, dass diese Metapher trotz ihrer rhetorischen Kraft in mindestens drei Hinsichten von einer kritischen Auseinandersetzung profitieren würde: Zu hinterfragen ist, wie sich die Wahrnehmung eines Schreis in der Urteilskraft und in der Praxis niederschlägt, wie die Metapher des Schreis menschlich-nichtmenschliche Beziehungen impliziert und wie der Schrei hilft, einen Weg zwischen Präzision und Unbestimmtheit zu finden. Eine solche kritische Auseinandersetzung trägt auf vier Arten zu unserem Verständnis der integralen Ökologie bei. Erstens bereichert sie, wie die integrale Ökologie die Zeichen der Zeit lesen kann. Zweitens bewahrt sie die integrale Ökologie vor mehreren zentralen Kritikpunkten, einschließlich der Kritik an ihrem Umgang mit dem Anthropozentrismus und an der Unfähigkeit, ihre Werte in der Realität umzusetzen. Drittens trägt sie zu Debatten über die Neuinterpretation von Werten wie Würde und Solidarität durch die integrale Ökologie bei. Viertens zeigt sie weitere Potentiale der Metapher auf – insbesondere legt sie eine Untersuchung nahe, wie der Schrei der Erde mit dem Schrei der Armen verwoben ist.The metaphor of the cry of the Earth is increasingly prominent within the rhetoric of integral ecology. This essay argues that, in spite of its rhetorical power, this metaphor would benefit from critical attention in at least three respects: how perceiving a cry translates into judgment and praxis, how the cry implicates human-nonhuman relations, and how the cry navigates specificity and vagueness. Such critical attention contributes to our understanding of integral ecology in four ways. First, it enhances the integral ecology’s reading of the “signs of the times.” Second, it deflects key critiques of integral ecology, including its handling of anthropocentrism and its inability to apply its values. Third, it speaks to conversations on integral ecology’s reimagining of the values of dignity and solidarity. Fourth, it points toward further applications, most notably an exploration of how the cry of the Earth relates to the cry of the poor

A disturbance based control/structure design algorithm

Some authors take a classical approach to the simultaneous structure/control optimization by attempting to simultaneously minimize the weighted sum of the total mass and a quadratic form, subject to all of the structural and control constraints. Here, the optimization will be based on the dynamic response of a structure to an external unknown stochastic disturbance environment. Such a response to excitation approach is common to both the structural and control design phases, and hence represents a more natural control/structure optimization strategy than relying on artificial and vague control penalties. The design objective is to find the structure and controller of minimum mass such that all the prescribed constraints are satisfied. Two alternative solution algorithms are presented which have been applied to this problem. Each algorithm handles the optimization strategy and the imposition of the nonlinear constraints in a different manner. Two controller methodologies, and their effect on the solution algorithm, will be considered. These are full state feedback and direct output feedback, although the problem formulation is not restricted solely to these forms of controller. In fact, although full state feedback is a popular choice among researchers in this field (for reasons that will become apparent), its practical application is severely limited. The controller/structure interaction is inserted by the imposition of appropriate closed-loop constraints, such as closed-loop output response and control effort constraints. Numerical results will be obtained for a representative flexible structure model to illustrate the effectiveness of the solution algorithms