A Base-Excitation Approach to Polynomial Chaos-Based Estimation

Abstract-This paper presents a novel method for identifying in real-time the sprung mass of a 2-DOF quarter-car suspension model. It does so by uniquely combining the base-excitation concept with polynomial chaos estimation. This unique combination of the two methods provides two important benefits. First, the base-excitation concept makes it possible to estimate the sprung mass without explicitly measuring or knowing the terrain profile prior to estimation. Second, the polynomial chaos estimation strategy makes it possible to perform such mass estimation using sprung and unsprung acceleration measurements without pseudo-integration filters that can be difficult to tune. This paper derives the proposed method in detail and presents computer simulations to evaluate its convergence speed and accuracy. The simulation results consistently converge to within 10% of the true mass value typically within 120 seconds

Markov-parameter-based adaptive control of 3-axis angular velocity in a six-degree-of-freedom Stewart platform

Abstract-Stewart platforms are complex mechanical devices used throughout industry for vibration testing and precision pointing applications. These platforms are nonlinear, strongly coupled MIMO systems. For a six-degree-of-freedom Stewart platform, we consider the problem of three-degree-of-freedom angular-velocity command following. Static nonlinearity inherent in the platform is analyzed, and a closed-loop setup for adaptive command-following control is described. A review of the Markov-parameter-based adaptive control algorithm is given, along with the OKID system identification algorithm, test procedures, and experimental results

Probability of major depression diagnostic classification using semi-structured vs. fully structured diagnostic interviews

Background: Different diagnostic interviews are used as reference standards for major depression classification in research. Semi-structured interviews involve clinical judgement, whereas fully structured interviews are completely scripted. The Mini International Neuropsychiatric Interview (MINI), a brief fully structured interview, is also sometimes used. It is not known whether interview method is associated with probability of major depression classification. Aims: To evaluate the association between interview method and odds of major depression classification, controlling for depressive symptom scores and participant characteristics. Method: Data collected for an individual participant data meta-analysis of Patient Health Questionnaire-9 (PHQ-9) diagnostic accuracy were analyzed. Binomial Generalized Linear Mixed Models were fit. Results: 17,158 participants (2,287 major depression cases) from 57 primary studies were analyzed. Among fully structured interviews, odds of major depression were higher for the MINI compared to the Composite International Diagnostic Interview (CIDI) [OR (95% CI) = 2.10 (1.15-3.87)]. Compared to semi-structured interviews, fully structured interviews (MINI excluded) were non-significantly more likely to classify participants with low-level depressive symptoms (PHQ-9 scores 6) as having major depression [OR (95% CI) = 3.13 (0.98-10.00)], similarly likely for moderate-level symptoms (PHQ-9 scores 7-15) [OR (95% CI) = 0.96 (0.56-1.66)], and significantly less likely for high-level symptoms (PHQ-9 scores 16) [OR (95% CI) = 0.50 (0.26-0.97)]. Conclusions: The MINI may identify more depressed cases than the CIDI, and semi- and fully structured interviews may not be interchangeable methods, but these results should be replicated

Mental health outcomes in HIV and childhood maltreatment: a systematic review

<p>Abstract</p> <p>Background</p> <p>High rates of childhood maltreatment have been documented in HIV-positive men and women. In addition, mental disorders are highly prevalent in both HIV-infected individuals and victims of childhood maltreatment. However, there is a paucity of research investigating the mental health outcomes associated with childhood maltreatment in the context of HIV infection. The present systematic review assessed mental health outcomes in HIV-positive individuals who were victims of childhood maltreatment.</p> <p>Methods</p> <p>A systematic search of all retrospective, prospective, or clinical trial studies assessing mental health outcomes associated with HIV and childhood maltreatment. The following online databases were searched on 25–31 August 2010: PubMed, Social Science Citation Index, and the Cochrane Library (the Cochrane Central Register of Controlled Trials and the Cochrane Developmental, Psychosocial and Learning Problems, HIV/AIDS, and Depression, Anxiety and Neurosis registers).</p> <p>Results</p> <p>We identified 34 studies suitable for inclusion. A total of 14,935 participants were included in these studies. A variety of mixed mental health outcomes were reported. The most commonly reported psychiatric disorders among HIV-positive individuals with a history of childhood maltreatment included: substance abuse, major depressive disorder, and posttraumatic stress disorder. An association between childhood maltreatment and poor adherence to antiretroviral regimens was also reported in some studies.</p> <p>Conclusion</p> <p>A broad range of adult psychopathology has been reported in studies of HIV-infected individuals with a history of childhood maltreatment. However, a direct causal link cannot be well established. Longer term assessment will better delineate the nature, severity, and temporal relationship of childhood maltreatment to mental health outcomes.</p