Maximizing the Closed Loop Asymptotic Decay Rate for the Two-Mass-Spring Control Problem

We consider the following problem: find a fixed-order linear controller that maximizes the closed-loop asymptotic decay rate for the classical two-mass-spring system. This can be formulated as the problem of minimizing the abscissa (maximum of the real parts of the roots) of a polynomial whose coefficients depend linearly on the controller parameters. We show that the only order for which there is a non-trivial solution is 2. In this case, we derive a controller that we prove locally maximizes the asymptotic decay rate, using recently developed techniques from nonsmooth analysis

“Girls Interrupted”: Young women ‘growing up’ in post-Katrina New Orleans: an exploration of the intersections of genders, sexualities and youth

This study draws on gender and disaster scholarship, feminist trans/methodology and queer theories to explore how growing up after Hurricane Katrina affected young women’s life course, particularly their gender and sexual identities. Gender and disaster scholarship has drawn out the gendered experience of disaster, demonstrating that on a general level, women experience disasters differently to men but also that their strengths, capacities and vulnerabilities can be invisibilised (Ariyabandu 2009; 2006; Bradshaw and Linneker 2009; Enarson 1998a; 1998b; Enarson and Meyreles 2004; Fordham 1998). Within this literature, research has highlighted that women’s disaster experiences cannot be overgeneralised and often intersecting identities and processes such as race, class, poverty and economic capacity can affect how women experience disasters (Bradshaw 2014; 2013; Bradshaw and Fordham 2013; David 2012; Enarson and David 2012; Enarson and Fordham 2007; Fordham 2004). It has also been documented that whilst some areas have been well-documented, others, such as youth and sexualities are rather unknown (D’Ooge 2008; Fothergill and Peek 2008; Fordham 2011; Galliard et al 2017). To this end, the study explores the difference between young women by taking an intersectionality approach to research, finding that for this particular group, sexualities were important in shaping their experiences growing up post-Katrina. Young women are neither adults nor children themselves and therefore are likely to have different needs and interests post-disaster because of these differences. This study shows that young women’s needs and interests vary depending on whether they were teenagers at the time of Katrina or whether they were ‘older’ young adults highlighting that youth cannot be seen as one generalised category, even when gender is taken into account. A key finding within this is around decision-making. Participants who were teenage girls at the time of Katrina often struggled with a lack of agency and decision-making power. Whilst ‘older’ young women participants were able to make their own decisions, some struggled with this control, particularly where they were making decisions about their lives and relationships for the first time. In this study, there was a particular focus on gender and sexualities because both are seen to be identities and processes that develop in young adulthood. Furthermore, young adulthood involves many “first times” for young people such as going away or going to college, beginning a new relationship and exploring sexual and gender identities. Under times of ‘normalcy’ these “first times” can be exciting and challenging but when a disaster occurs, they are often altered in various ways. This study finds that post-Katrina, the way that experiences are altered was not necessarily always negative. Rather, some changed their lives for the better because Katrina opened up new spaces which enabled the young women in the study to make choices they did not feel they could make before. The findings highlight that young women can experience similar issues post-disaster as their adult counterparts such as fear of violence and gender based violence (GBV) as well as health and mental health issues but their stages in lifecourse change the way these processes are experienced. Furthermore, young women face specific issues to their cohort such as making “first time” decisions in a time of crisis. Overall, the events that young women found to be most important post-disaster were processes that were already affecting their lives but had come to the fore as a result of Katrina. For participants in this study, these processes included ‘coming out’ as queer, exploring their sexual and gender identities and becoming or extending their involvement in drag king performance. However, there continued to be an ‘age divide’ where young women who were teenage girls at the time had less access to collective space due to the adult environment these spaces operated within. Ignoring young women’s unique concerns could have longterm impacts where disasters open up new space, but young women are not able to access it. Overall, the findings of this study show that young women’s coping mechanisms and vulnerabilities post-disaster are unique. Furthermore, young women’s ability to be resourceful in times of uncertainty and crisis should not be underestimated. Most participants found ways to deal with the aftermath of the post-disaster events such as evacuation, displacement and return in creative and imaginative ways. Even though very little is known about their experiences, this study has found that young women can be highly active, both personally and collectively in engaging in positive change for themselves and their communities. Through their lack of childcare responsibilities and by not being children themselves, young women have been invisibilised in disaster research but this study shows that they are resourceful, imaginative post-disaster actors who are able to use new spaces, both collective and individual to make positive changes in their communities and their lives based not only on their needs, but also on their interests and desires even where they have been ignored

Multiobjective Robust Control with HIFOO 2.0

Multiobjective control design is known to be a difficult problem both in theory and practice. Our approach is to search for locally optimal solutions of a nonsmooth optimization problem that is built to incorporate minimization objectives and constraints for multiple plants. We report on the success of this approach using our public-domain Matlab toolbox HIFOO 2.0, comparing our results with benchmarks in the literature

A Data Transformation System for Biological Data Sources

Scientific data of importance to biologists in the Human Genome Project resides not only in conventional databases, but in structured files maintained in a number of different formats (e.g. ASN.1 and ACE) as well a.s sequence analysis packages (e.g. BLAST and FASTA). These formats and packages contain a number of data types not found in conventional databases, such as lists and variants, and may be deeply nested. We present in this paper techniques for querying and transforming such data, and illustrate their use in a prototype system developed in conjunction with the Human Genome Center for Chromosome 22. We also describe optimizations performed by the system, a crucial issue for bulk data

Extractive industries as sites of supernormal profits and supernormal patriarchy?

This article considers how patriarchal power relations between men and women are produced and reproduced within extractive industries, and examines the idea that the ‘supernormal profits’ to be made there encourage the development of ‘supernormal patriarchy’. By looking at the sites where extraction takes place and relationships between men and women within these sites, we show the extreme and exaggerated gender roles and relations that are found here. We nuance this account by highlighting the need to recognise that patriarchal power is not felt equally by all women and men. Exploring the different roles women adopt in the extractives context we demonstrate the fluidity of women’s identities as workers, ‘whores’, and wives with a focus on transactional sex. The article demonstrates the importance of not seeing women merely as victims of patriarchal relations, or making assumptions about how these relations operate, or the form they take. Better understanding of the range of gender roles adopted in the extractives and the supernormal patriarchal relations that produce and reproduce these is needed by policymakers. This will enable them to promote gender equality and natural resource justice, as part of an agenda to redistribute wealth gains from natural resource extraction

On the Choice of Sign Defining Householder Transformations

It is well known that, when defining Householder transformations, the correct choice of sign in the standard formula is important to avoid cancellation and hence numerical instability. In this note we point out that when the "wrong" choice of sign is used, the extent of the resulting instability depends in a somewhat subtle way on the data leading to cancellation