A nonlinear observer for 6 DOF pose estimation from inertial and bearing measurements

Abstract — This paper considers the problem of estimating pose from inertial and bearing-only vision measurements. We present a non-linear observer that evolves directly on the special Euclidean group SE(3) from inertial measurements and bearing measurements, such as provided by a visual system tracking known landmarks. Local asymptotic convergence of the observer is proved. The observer is computationally simple and its gains are easy to tune. Simulation results demonstrate robustness to measurement noise and initial conditions

Inversion of hyperelliptic integrals of arbitrary genus with application to particle motion in General Relativity

The description of many dynamical problems like the particle motion in higher dimensional spherically and axially symmetric space-times is reduced to the inversion of a holomorphic hyperelliptic integral. The result of the inversion is defined only locally, and is done using the algebro-geometric techniques of the standard Jacobi inversion problem and the foregoing restriction to the $\theta$--divisor. For a representation of the hyperelliptic functions the Klein--Weierstra{\ss} multivariable sigma function is introduced. It is shown that all parameters needed for the calculations like period matrices and Abelian images of branch points can be expressed in terms of the periods of holomorphic differentials and theta-constants. The cases of genus two and three are considered in detail. The method is exemplified by particle motion associated with a genus three hyperelliptic curve

Institutional change in the international governance of agriculture: a revised account

The place of agriculture in the General Agreement on Tariffs and Trade (GATT) prior to 1986 is usually described in terms of either exclusion or exemption from general trading rules. This paper reevaluates the ‘exemption’ argument and its corollary that the Uruguay Round Agreement on Agriculture (AoA) represented a punctuated equilibrium in the governance of agriculture. Instead it traces the dynamics of institutional change through the history of the GATT/WTO, distinguishing between multilateral trading rounds and the framework of trade rules as separate but linked contexts for addressing agricultural trade matters; and further disaggregating the latter into broad principles and specific rules. It is argued that the broad principles lacked detail but, paradoxically, initially this facilitated an approach to dispute settlement based on conciliation. Subsequent trade tensions exposed an inability to make definitive legal decisions on the compatibility of specific national rules with broad GATT principles. The AoA is rooted in these institutional antecedents, but claims of the legalization of the trade regime are belied by a continued reliance on political flexibility and bargaining

Carers’ responses to shifting identity in dementia in Iris and Away From Her: cultivating stability or embracing change?

An emphasis on supporting and maintaining self-identity in people who have dementia for as long as possible has gone hand in hand with the revitalisation of dementia interventions, services and empowerment. However, recognition of the need for change, adaptation and personal growth is as necessary when living with dementia as at any other time in people's lives. Those who care for people with dementia must constantly navigate this tension between continuity and change within the context of memory loss, knowing when to respond by reinforcing the ‘self’ they have known over time, and when it may be better to respond by acknowledging the changes that have taken place in that ‘self’. The creative arts are avenues for the exploration of the caring relationship under these conditions, conveying the challenges and stimulating audiences to ask how they themselves might choose to respond in a similar situation. This article considers how the scenarios of two noted films, Iris (dir. Richard Eyre, 2001 UK)) and Away From Her (dir. Sarah Polley, 2006 Can), present the dilemmas of identity and caring. In both, a husband cares for a wife experiencing cognitive decline, but responds differently in each to her shifting needs and experience of identity. We argue that the two films reveal complementary and provocative perspectives on this situation. They offer no easy answers, but provide insights into the everyday decisions characteristic of caring for someone who has dementia

The ‘Abstainer Question’: relationships between alcohol use and suicidal ideation in Australian online help-seekers

Background: When compared to social drinkers, high levels of suicidal ideation have been observed in both heavy alcohol consumers and abstainers. Heavy alcohol use or abstention may indicate different risk pathways to the development of suicidal ideation (SI). Methods: Visitors to a mental health website (N = 1,561) completed a survey, and latent profile analysis (LPA) was used to explore differences in risk factor patterns. Risk factors explored included psychological distress, help-seeking intent, financial wellbeing, thwarted belongingness and perceived burdensomeness. Results: Most participants (75.1%) reported SI in the past four weeks. A three-class LPA model emerged as the optimal fit: (1) low SI/lower alcohol; (2) high SI/lower alcohol; (3) high SI/high alcohol. Members of the high SI/lower alcohol profile displayed significantly higher psychological distress, thwarted belongingness, and perceived burdensomeness; lower financial wellbeing and help-seeking intentions than both other profiles. Members of the high SI/high alcohol profile were more likely to be male and already receiving help for their psychological distress. Members of the high SI/lower alcohol profile were more likely to be younger and report lower help-seeking intent. Limitations: Our study design was cross-sectional, utilising a largely young, female, English-speaking, help-seeking sample that had chosen to visit a mental health website. Conclusions: While the links between heavy alcohol use and suicide risk are well documented, these findings suggest that practitioners should also be alert for abstention patterns, as they may be indicators of underlying psychosocial concerns that a client could be reluctant to disclose

Assessing the Significance of Conserved Genomic Aberrations Using High Resolution Genomic Microarrays

Genomic aberrations recurrent in a particular cancer type can be important prognostic markers for tumor progression. Typically in early tumorigenesis, cells incur a breakdown of the DNA replication machinery that results in an accumulation of genomic aberrations in the form of duplications, deletions, translocations, and other genomic alterations. Microarray methods allow for finer mapping of these aberrations than has previously been possible; however, data processing and analysis methods have not taken full advantage of this higher resolution. Attention has primarily been given to analysis on the single sample level, where multiple adjacent probes are necessarily used as replicates for the local region containing their target sequences. However, regions of concordant aberration can be short enough to be detected by only one, or very few, array elements. We describe a method called Multiple Sample Analysis for assessing the significance of concordant genomic aberrations across multiple experiments that does not require a-priori definition of aberration calls for each sample. If there are multiple samples, representing a class, then by exploiting the replication across samples our method can detect concordant aberrations at much higher resolution than can be derived from current single sample approaches. Additionally, this method provides a meaningful approach to addressing population-based questions such as determining important regions for a cancer subtype of interest or determining regions of copy number variation in a population. Multiple Sample Analysis also provides single sample aberration calls in the locations of significant concordance, producing high resolution calls per sample, in concordant regions. The approach is demonstrated on a dataset representing a challenging but important resource: breast tumors that have been formalin-fixed, paraffin-embedded, archived, and subsequently UV-laser capture microdissected and hybridized to two-channel BAC arrays using an amplification protocol. We demonstrate the accurate detection on simulated data, and on real datasets involving known regions of aberration within subtypes of breast cancer at a resolution consistent with that of the array. Similarly, we apply our method to previously published datasets, including a 250K SNP array, and verify known results as well as detect novel regions of concordant aberration. The algorithm has been fully implemented and tested and is freely available as a Java application at http://www.cbil.upenn.edu/MSA