State and input simultaneous estimation for a class of time-delay systems with uncertainties

This brief addresses the problem of estimation of both the states and the unknown inputs of a class of systems that are subject to a time-varying delay in their state variables, to an unknown input, and also to an additive uncertain, nonlinear disturbance. Conditions are derived for the solvability of the design matrices of a reduced-order observer for state and input estimation, and for the stability of its dynamics. To improve computational efficiency, a delay-dependent asymptotic stability condition is then developed using the linear matrix inequality formulation. A design procedure is proposed and illustrated by a numerical example.

Thats classified: class politics and adolescence in twin peaks

Twin Peaks arguably paved the way for the television programmes currently popular with adolescent audiences, like The OC and Veronica Mars and, in it, many of the issues and representational strategies in those later programmes have their earlier manifestation. Specifically, the Twin Peaks plotline evinces a set of cultural anxieties about class-difference. Twin Peaks creates a cultural microcosm of American society that is paradoxically writ large by the limited parameters of an isolated community. Within a constricted space, characters are depicted as both individuals and as archetypes of a class location.

The cost of storing checkpoints to multiple volatile storage locations using at-least-k semantics

Using the volatile memory of other computers within a system to store checkpoints is an alternative to the traditional approach of using stable storage. The objective of this study is to develop a storage mechanism using at-least-k delivery semantics. This semantics allows data to be saved to a minimum number of computers simultaneously using group communications, without requiring that each group computer successfully acknowledge the receipt. The new storage mechanism is implemented in the GENESIS checkpointing facility v2.0. The results showed that at-least-k storage mechanisms provide low storage latency times; however, the incurred execution overheads on the applications executing within the system are higher than that when using remote stable storage to store checkpoints.

Public finance and income redistribution in interwar Australia: towards a class analysis

In this paper I focus on a neglected aspect of Australian political history, the extent to which Australian governments actually redistributed income. The German sociologist Rudolf Goldscheid argued that 'the budget is the skeleton of the state stripped of all misleading ideologies'. In Australia a party that claimed to represent lower income earners, the Labor Party, was a major political force, but did Labor actually make a difference to the distribution of income across social classes, or did Labor's rhetoric of equity merely serve to incorporate workers into the capitalist system? A quantitative approach to the political history of labour may enable us to escape both nostalgia for old labourism (which the Howard years have encouraged) and a simple and undifferentiated rejection of labourism as a reformist agent of social integration.

This paper incorporates some material from a 2005 paper that examined overall expenditure patterns and taxation patterns across the states and Commonwealth from 1910 to 1940 but it goes beyond the aggregate approach of this paper to consider the extent which the varying patterns of taxation and public expenditure across Australia impacted on different social classes during the 1930s. It is very much a preliminary analysis based on existing compilations of taxation statistics. It is a static analysis and does not consider if nominally redistributive taxation and expenditure patterns might be rendered ineffective by consequent interstate migration.

syn-Facial hetero-bridged [n]polynorbornanes : a new class of polarofacial framework molecules composed of fused 7-oxa- and 7-azanorbornanes

New oxygen-bridged norbornane-fused cyclobutene epoxides and bis-(cyclobutene epoxides) are described and shown to react stereoselectively with 7-azanorbornenes to produce syn-facial N,O-bridged polynorbornanes and stereorandomly with 7-oxanorbornenes to produce O,O-bridged polynorbornanes as mixtures of syn-facial and anti-facial products.[1] Polarofacial systems containing up to six syn-facial norbornane bridges are described, while systems with seven co-facial oxygen atoms have been prepared by incorporating terminal epoxide rings to O5-[5]polynorbornanes. Ester-substituted 1,3,4-oxadiazoles are shown to be useful reagents for coupling 7-oxanorbornanes and produce predominantly syn-facial O-bridged polarofacial systems together with their anti-facial isomers.

Synthesis of [n]polynorbornanes with differing edge substitution: a new class of regioselectively addressable framework

Polynorbornanes with differing edge functionality have been synthesised from the appropriate cyclobutene epoxides substituted with two, unlike, electron withdrawing groups. These latter compounds were prepared by the monohydrolysis of symmetric cyclobutene diesters and subsequent elaboration of the resulting carboxylic acid.

"As long as it doesn't spill over into class": harms arising from students` alcohol use, and the role of policy in reducing them

While there is considerable evidence about the prevalence of student alcohol use, little empirical work has examined the range and level of exposure to alcohol-related risks facing student populations, and the views of key stakeholders about these. This study was conducted at a large multi-campus university in order to gauge the scale and severity of students’ alcohol-related problems, and ways in which these may be mitigated. Student perspectives on campus based policy making with respect to alcohol were also canvassed. This study utilised a range of evaluative instruments, including standardised questionnaire protocols, structured interviews and focus groups. Data gained from students showed a large level of exposure to alcohol-related harm, and staff informants reported student harms such as drink-driving, interpersonal aggression, social nuisance, inadequate security, sexually risky behaviour, and physical malaise. As a group, students seem receptive to campus-based policies that have a harm reduction focus, but are less supportive of institutionalised measures aimed at the student body. Given the divergence of views about the harms arising from student drinking, and a general repudiation of institutional policy measures which may lessen these, the development of harm-reducing policy on alcohol remains challenging.

Reliability and validity of physical activity questionnaires for children: the children's leisure activities study survey (CLASS)

Examines the development of a reliable, valid and feasible method for assessing physical activity among children ages 5-6 and 10-12 years. Information on the subjects of the study; Assessment of test-retest reliability of a parental proxy questionnaire and a children's self-report questionnaire; Utilization of accelerometry to assess the criterion validity of the questionnaire.

Bayesian classification of catchments using spatial data: a first step to improved modelling of catchment effects on stream ecological condition

A major challenge facing freshwater ecologists and managers is the development of models that link stream ecological condition to catchment scale effects, such as land use. Previous attempts to make such models have followed two general approaches. The bottom-up approach employs mechanistic models, which can quickly become too complex to be useful. The top-down approach employs empirical models derived from large data sets, and has often suffered from large amounts of unexplained variation in stream condition.

We believe that the lack of success of both modelling approaches may be at least partly explained by scientists considering too wide a breadth of catchment type. Thus, we believe that by stratifying large sets of catchments into groups of similar types prior to modelling, both types of models may be improved. This paper describes preliminary work using a Bayesian classification software package, ‘Autoclass’ (Cheeseman and Stutz 1996) to create classes of catchments within the Murray Darling Basin based on physiographic data.

Autoclass uses a model-based classification method that employs finite mixture modelling and trades off model fit versus complexity, leading to a parsimonious solution. The software provides information on the posterior probability that the classification is ‘correct’ and also probabilities for alternative classifications. The importance of each attribute in defining the individual classes is calculated and presented, assisting description of the classes. Each case is ‘assigned’ to a class based on membership probability, but the probability of membership of other classes is also provided. This feature deals very well with cases that do not fit neatly into a larger class. Lastly, Autoclass requires the user to specify the measurement error of continuous variables.

Catchments were derived from the Australian digital elevation model. Physiographic data werederived from national spatial data sets. There was very little information on measurement errors for the spatial data, and so a conservative error of 5% of data range was adopted for all continuous attributes. The incorporation of uncertainty into spatial data sets remains a research challenge.

The results of the classification were very encouraging. The software found nine classes of catchments in the Murray Darling Basin. The classes grouped together geographically, and followed altitude and latitude gradients, despite the fact that these variables were not included in the classification. Descriptions of the classes reveal very different physiographic environments, ranging from dry and flat catchments (i.e. lowlands), through to wet and hilly catchments (i.e. mountainous areas). Rainfall and slope were two important discriminators between classes. These two attributes, in particular, will affect the ways in which the stream interacts with the catchment, and can thus be expected to modify the effects of land use change on ecological condition. Thus, realistic models of the effects of land use change on streams would differ between the different types of catchments, and sound management practices will differ.

A small number of catchments were assigned to their primary class with relatively low probability. These catchments lie on the boundaries of groups of catchments, with the second most likely class being an adjacent group. The locations of these ‘uncertain’ catchments show that the Bayesian classification dealt well with cases that do not fit neatly into larger classes.

Although the results are intuitive, we cannot yet assess whether the classifications described in this paper would assist the modelling of catchment scale effects on stream ecological condition. It is most likely that catchment classification and modelling will be an iterative process, where the needs of the model are used to guide classification, and the results of classifications used to suggest further refinements to models.

Class act : Melbourne Workers Theatre, 1987-2007

Celebrates the company's artistic achievements and successes over the last two decades through interviews, essays and high quality images of key productions, and recounts its history, its evolving relationship with the embattled trade union movement, and its on-going engagement with working class, indigenous and migrant communities.

'Class' and political theatre : the case of Melbourne workers theatre

Traditionally, class has been an important category of identity in discussions of political theatre. However, in recent years the concept has fallen out of favour, partly because of changes in the forces and relations of capitalist production. The conventional Marxist use of the term, which defined an individual's class position in relation to the position they occupied in the capitalist production process, seemed anachronistic in an era of globalization. Moreover, the rise of identity politics, queer theory, feminism, and post-colonialism have proffered alternative categories of identity that have displaced class as the primary marker of self. Glenn D'Cruz reconsiders the role of class in the cultural life of Australia by examining the recent work of Melbourne Workers Theatre, a theatre company devoted to promoting class-consciousness, in relation to John Frow's more recent re-conceptualization of class. He looks specifically at two of the company's plays, the award-winning Who's Afraid of the Working Class? and The Waiting Room, with reference to Frow's work on class, arguing that these productions articulate a more complex and sophisticated understanding of class and its relation to politics of race and gender today.

Class action

Hannie Rayson followed the success of her play Life After George (2000) with Inheritance. It is a rural family saga set in Victoria's Mallee region where two families, headed by eighty-year-old twin sisters Dibs and Girlie, battle it out for possession of the family farm. The play, directed by Simon Phillips, was performed in March 2003 to capacity audiences at the Melbourne Theatre Company, and then at the Sydney Theatre Company in April-May 2003. Rayson's most recent play, Two Brothers, opened at the Playhouse, Victorian Arts Centre, in April 2005.

Assessment of physical activity among primary school aged children: the Children's Leisure Activities Study (CLASS)

Overweight and obesity rates among children in Australia have increased twofold in the last decade. Physical activity is thought to play an important role in the prevention and treatment of childhood obesity. Children's physical activity data in Australia are incomplete and mainly based on parental proxy reports. One of the reasons for the lack of children's physical activity prevalence data in Australia is the difficulties of measurement. The aim of this study was to develop and examine a reliable, valid and feasible method for assessing physical activity among primary school aged children. A total of 112 grade 5 and 6 children and their parents were recruited from four state primary schools in the eastern and western suburbs of Melbourne. The test-retest reliability of a parental proxy physical activity questionnaire and a children's self report physical activity questionnaire was assessed. The criterion validity of the questionnaires was assessed using accelerometry. Findings suggest that the self report and proxy report questionnaires provided reliable measures of the type, frequency and duration of children's physical activity behaviour. Overall, the criterion validity of the questionnaires was poor. Although accelerometry as an objective measure shows promise, it does not provide the important physical activity behavioural and contextual information that is critical for the development of strategies to promote physical activity among children. We recommend that a combination of self report or proxy and objective measurement (using accelerometry or even pedometry) appears to be the current 'best buy' in the assessment of children's physical activity behaviour.