Controlled Sequential Monte Carlo

Sequential Monte Carlo methods, also known as particle methods, are a popular set of techniques for approximating high-dimensional probability distributions and their normalizing constants. These methods have found numerous applications in statistics and related fields; e.g. for inference in non-linear non-Gaussian state space models, and in complex static models. Like many Monte Carlo sampling schemes, they rely on proposal distributions which crucially impact their performance. We introduce here a class of controlled sequential Monte Carlo algorithms, where the proposal distributions are determined by approximating the solution to an associated optimal control problem using an iterative scheme. This method builds upon a number of existing algorithms in econometrics, physics, and statistics for inference in state space models, and generalizes these methods so as to accommodate complex static models. We provide a theoretical analysis concerning the fluctuation and stability of this methodology that also provides insight into the properties of related algorithms. We demonstrate significant gains over state-of-the-art methods at a fixed computational complexity on a variety of applications

Bridging the Works of Horace, Catullus, Ovid, and Haydock

I wrote this thesis to explore the metrical poetry of Horace, Catullus, and Ovid, as well as my own poetry and short fiction. I parsed the Latin poems, word-by-word, and provided literal translations, as well as idiomatic translations of selected poems by Horace and Ovid. In order to link these translations to my short story, Into the Last Good Fight, I wrote three metrical poems that synthesize the themes, concepts, and structures of my story with the themes, concepts, and structures of the Latin poems. To provide an even stronger link between the Latin portion of my thesis and the English portion, I translated two of my own poems into Latin, using the same literal method. My translations are as literal as possible, so that even a beginning Latin student could understand my grammatical interpretation, but as I note in my introduction, my literal translations of the Latin at times fall short of comprehensibility in English. I struggled with being both literal and true to the Latin, which is why I also offered idiomatic translations, which are more comprehensible, in order to convey a fuller meaning of the text. This thesis demonstrates how my scholarly pursuits of English and Latin have worked together to mutually benefit one another

Informed consent and placebo effects: a content analysis of information leaflets to identify what clinical trial participants are told about placebos

BackgroundPlacebo groups are used in randomised clinical trials (RCTs) to control for placebo effects, which can be large. Participants in trials can misunderstand written information particularly regarding technical aspects of trial design such as randomisation; the adequacy of written information about placebos has not been explored. We aimed to identify what participants in major RCTs in the UK are told about placebos and their effects.Methods and FindingsWe conducted a content analysis of 45 Participant Information Leaflets (PILs) using quantitative and qualitative methodologies. PILs were obtained from trials on a major registry of current UK clinical trials (the UKCRN database). Eligible leaflets were received from 44 non-commercial trials but only 1 commercial trial. The main limitation is the low response rate (13.5%), but characteristics of included trials were broadly representative of all non-commercial trials on the database. 84% of PILs were for trials with 50:50 randomisation ratios yet in almost every comparison the target treatments were prioritized over the placebos. Placebos were referred to significantly less frequently than target treatments (7 vs. 27 mentions, p<001) and were significantly less likely than target treatments to be described as triggering either beneficial effects (1 vs. 45, p<001) or adverse effects (4 vs. 39, p<001). 8 PILs (18%) explicitly stated that the placebo treatment was either undesirable or ineffective.ConclusionsPILs from recent high quality clinical trials emphasise the benefits and adverse effects of the target treatment, while largely ignoring the possible effects of the placebo. Thus they provide incomplete and at times inaccurate information about placebos. Trial participants should be more fully informed about the health changes that they might experience from a placebo. To do otherwise jeopardises informed consent and is inconsistent with not only the science of placebos but also the fundamental rationale underpinning placebo controlled trials

High Performance, Continuously Tunable Microwave Filters using MEMS Devices with Very Large, Controlled, Out-of-Plane Actuation

Software defined radios (SDR) in the microwave X and K bands offer the promise of low cost, programmable operation with real-time frequency agility. However, the real world in which such radios operate requires them to be able to detect nanowatt signals in the vicinity of 100 kW transmitters. This imposes the need for selective RF filters on the front end of the receiver to block the large, out of band RF signals so that the finite dynamic range of the SDR is not overwhelmed and the desired nanowatt signals can be detected and digitally processed. This is currently typically done with a number of narrow band filters that are switched in and out under program control. What is needed is a small, fast, wide tuning range, high Q, low loss filter that can continuously tune over large regions of the microwave spectrum. In this paper we show how extreme throw MEMS actuators can be used to build such filters operating up to 15 GHz and beyond. The key enabling attribute of our MEMS actuators is that they have large, controllable, out-of-plane actuation ranges of a millimeter or more. In a capacitance-post loaded cavity filter geometry, this gives sufficient precisely controllable motion to produce widely tunable devices in the 4-15 GHz regime.Comment: 12 pages 14 figures 2 table

A Review of Psychosocial Predictors of Treatment Outcomes: What Factors Might Determine the Clinical Success of Acupuncture for Pain?

AbstractThis narrative review examines the psychosocial factors that might predict clinical outcomes in acupuncture for pain. Given existing evidence concerning the clinical effectiveness and safety of acupuncture in painful conditions, it is important to consider how clinicians might further improve their effectiveness. The relevant theoretical frameworks focus primarily on the patient, suggesting that their background characteristics and their beliefs about pain and acupuncture should be considered as potential predictors of outcome. The self-regulation model within health psychology helps us understand how people manage their health and integrate interventions like acupuncture into the management of their illness. This model also implies that the therapeutic relationship, in particular patients' perceptions of that relationship, is likely to be related to outcome. The empirical literature in this area is sparse. However, the findings to date do suggest that a number of psychosocial factors, in particular patients' beliefs about acupuncture, are significant predictors of treatment outcomes from acupuncture for pain. Factors related to the therapeutic relationship are also likely to be important in facilitating good clinical outcomes. We discuss the limitations of the existing studies and make recommendations for future research in this area. If we can better understand the psychosocial factors involved in acupuncture, then we should be able to enhance acupuncture treatments and improve outcomes for patients. These observations will, therefore, have potential to allow us to develop techniques that may improve clinical outcomes in the treatment of pain

Mems device with large out-of-plane actuation and low-resistance interconnect and methods of use

Source: United States Patent and Trademark Office, www.uspto.gov”The present application is directed to a MEMS device. The MEMS device includes a substrate having a first end and a second end extending along a longitudinal axis, the Substrate including an electrostatic actuator. The device also includes a movable plate having a first end and a second end. The device also includes a thermal actuator having a first end coupled to the first end of the substrate and a second end coupled to the first end of the plate. The actuator moves the plate in relation to the substrate. Further, the device includes a power source electrically coupled to the thermal actuator and the Substrate. The application is also directed to a method for operating a MEMS device

Collective oscillations of a trapped Fermi gas near the unitary limit

We calculate the oscillation frequencies of trapped Fermi condensate with particular emphasis on the equation of state of the interacting Fermi system. We confirm Stringari's finding that the frequencies are independent of the interaction in the unitary limit, and we extend the theory away from that limit, where the interaction does affect the frequencies of the compressional modes only.Comment: 4 pages, corrected a couple of trivial mistakes in table II and the related text and added reference