1,096 research outputs found

    1-Bit Matrix Completion

    Full text link
    In this paper we develop a theory of matrix completion for the extreme case of noisy 1-bit observations. Instead of observing a subset of the real-valued entries of a matrix M, we obtain a small number of binary (1-bit) measurements generated according to a probability distribution determined by the real-valued entries of M. The central question we ask is whether or not it is possible to obtain an accurate estimate of M from this data. In general this would seem impossible, but we show that the maximum likelihood estimate under a suitable constraint returns an accurate estimate of M when ||M||_{\infty} <= \alpha, and rank(M) <= r. If the log-likelihood is a concave function (e.g., the logistic or probit observation models), then we can obtain this maximum likelihood estimate by optimizing a convex program. In addition, we also show that if instead of recovering M we simply wish to obtain an estimate of the distribution generating the 1-bit measurements, then we can eliminate the requirement that ||M||_{\infty} <= \alpha. For both cases, we provide lower bounds showing that these estimates are near-optimal. We conclude with a suite of experiments that both verify the implications of our theorems as well as illustrate some of the practical applications of 1-bit matrix completion. In particular, we compare our program to standard matrix completion methods on movie rating data in which users submit ratings from 1 to 5. In order to use our program, we quantize this data to a single bit, but we allow the standard matrix completion program to have access to the original ratings (from 1 to 5). Surprisingly, the approach based on binary data performs significantly better

    Pilot scale pyrolysis - determination of critical moisture content for sustainable organic waste pyrolysis

    Get PDF
    Economic feasibility of large scale organic waste pyrolysis was investigated for Inghams Enterprise (Waitoa) chicken dissolved air flotation sludge (DAF) and activated sludge (biosolids) from the Hamilton municipal waste water treatment plant. Processing data was obtained from pilot plant trials using the Lakeland Steel (Rotorua) continuous auger pyrolysis plant using feedstock at 15, 30, 45 and ~80% moisture contents. Economics were calculated based on estimated capital and operating costs of a large scale facility, revenue from selling char, savings from landfill diversion (including transportation and gate costs), energy savings by recycling syngas product and using waste heat for drying feedstock. For DAF, 15% moisture content gave yields of 21% syngas, 27% char, and 52% oil (dry weight basis). 15% moisture content gave the best processing conditions based on handling properties and degree of autogenesis. The DAF case does not give a payback period due to low scale of operations. For biosolids, 15% moisture content feedstock gave yields of 46% syngas, 31% char, and 21% oil (wet weight). Difficulties were found with plant blockages at 45% and 80% moisture contents. 15% moisture content gave the best processing conditions and the best economic performance with a payback time of 4.6 years for a facility that could process 11,000 tonnes per year

    Ultrahigh risk for developing psychosis and psychotic personality organization

    Get PDF
    Aims: Childhood adversities combined with unsafe parenting may disturb personality development. This study investigated whether psychotic personality organization as defined by Kernberg and assessed with de Dutch Short Form of the MMPI (DSFM) is more prevalent in ultrahigh risk (UHR) for psychosis compared with non-psychotic psychiatric control patients (NPPC). Methods: A total of 73 UHR and 119 NPPC patients were assessed with the DSFM and the Comprehensive Assessment of at Risk Mental States (CAARMS). Results: The results showed that the psychotic personality organization (PPO) was not associated to UHR status. The UHR group showed more severe symptoms, particularly higher scores on DSFM subscales negativism (negative affect) and somatization (vague somatic complaints) and severe psychopathology (psychotic symptoms and dissociation). Conclusion: The PPO profile is not associated to the risk of developing psychosis

    The contributions of family care-givers at end of life: A national post-bereavement census survey of cancer carers' hours of care and expenditures.

    Get PDF
    BACKGROUND: Family members provide vital care at end of life, enabling patients to remain at home. Such informal care contributes significantly to the economy while supporting patients' preferences and government policy. However, the value of care-givers' contributions is often underestimated or overlooked in evaluations. Without information on the activities and expenditures involved in informal care-giving, it is impossible to provide an accurate assessment of carers' contribution to end-of-life care. AIM: The aim of this study was to investigate the contributions and expenditure of informal, family care-giving in end-of-life cancer care. DESIGN: A national census survey of English cancer carers was conducted. Survey packs were mailed to 5271 people who registered the death of a relative to cancer during 1-16 May 2015. Data were collected on decedents' health and situation, care support given, financial expenditure resulting from care, carer well-being and general background information. RESULTS: In all, 1504 completed surveys were returned (28.5%). Over 90% of respondents reported spending time on care-giving in the last 3 months of the decedent's life, contributing a median 69 h 30 min of care-giving each week. Those who reported details of expenditure (72.5%) spent a median £370 in the last 3 months of the decedent's life. CONCLUSION: Carers contribute a great deal of time and money for day-to-day support and care of patients. This study has yielded a unique, population-level data set of end-of-life care-giving and future analyses will provide estimates of the economic value of family care-givers' contributions

    Webinar: A Faculty Perspective on COIL: A Sheridan Experience!

    Get PDF
    During the winter 2021 semester, two pilot Collaborative Online International Learning(COIL) courses were conducted within Sheridan - one within the Faculty of Humanities and Social Sciences (FHASS) and the other within Pilon School of Business (PSB). This webinar aims to capitalize on the knowledge gained by our Sheridan members from those pilot courses and learn from their experiences to benefit others moving forward. We will also highlight the different services available for our faculty and staff to support them throughout their COIL journey. Speakers: Peter Galambos, Professor, Faculty of Humanities and Social Sciences – Sheridan Mark Weaver, Professor, Pilon School of Business – Sheridan Stan Kamzol, Professor and International Academic Exchange Coordinator, Pilon School of Business – Sheridan Edwin van den Berg, Professor - Saxion University of Applied Sciences Moderated by: Amira El Masri, Director of the Centre for Global Education and Internationalization – Sheridanhttps://source.sheridancollege.ca/cgei_events/1000/thumbnail.jp

    Linguistic dual tasking reduces emotionality, vividness and credibility of voice memories in voice-hearing individuals:Results from a controlled trial

    Get PDF
    Dual taxation of the working memory during recall is an effective strategy to reduce the emotionality and vividness of visual intrusive memories and potentially changes dysfunctional beliefs associated with the memories. This study tested the hypothesis that dual tasking decreases emotionality, vividness and credibility of auditory intrusive images (i.e., memories of auditory hallucinations) with a two-level (time: pre and post; condition: dual tasking and recall only) within-subjects design. Thirty-seven voice-hearing participants selected two negative voice-hearing experiences. They recalled one of these experiences while performing a lingual dual task (i.e., language game on smartphone app) and recalled one memory without a dual task (in counterbalanced order). During the pre-test and post-test, emotionality and vividness of the voice-hearing memories were rated, as well as the credibility of the voice statements. There was a significantly greater decrease in emotionality, vividness and credibility during dual tasking than during recall only. This study provides proof of principle that the salience and credibility of the content of auditory hallucinations can be reduced by dual tasking; the clinical implications are also discussed
    corecore