394 research outputs found

    Robust explicit MPC design under finite precision arithmetic

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    We propose a design methodology for explicit Model Predictive Control (MPC) that guarantees hard constraint satisfaction in the presence of finite precision arithmetic errors. The implementation of complex digital control techniques, like MPC, is becoming increasingly adopted in embedded systems, where reduced precision computation techniques are embraced to achieve fast execution and low power consumption. However, in a low precision implementation, constraint satisfaction is not guaranteed if infinite precision is assumed during the algorithm design. To enforce constraint satisfaction under numerical errors, we use forward error analysis to compute an error bound on the output of the embedded controller. We treat this error as a state disturbance and use this to inform the design of a constraint-tightening robust controller. Benchmarks with a classical control problem, namely an inverted pendulum, show how it is possible to guarantee, by design, constraint satisfaction for embedded systems featuring low precision, fixed-point computations

    Energy-aware MPC co-design for DC-DC converters

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    In this paper, we propose an integrated controller design methodology for the implementation of an energy-aware explicit model predictive control (MPC) algorithms, illustrat- ing the method on a DC-DC converter model. The power consumption of control algorithms is becoming increasingly important for low-power embedded systems, especially where complex digital control techniques, like MPC, are used. For DC-DC converters, digital control provides better regulation, but also higher energy consumption compared to standard analog methods. To overcome the limitation in energy efficiency, instead of addressing the problem by implementing sub-optimal MPC schemes, the closed-loop performance and the control algorithm power consumption are minimized in a joint cost function, allowing us to keep the controller power efficiency closer to an analog approach while maintaining closed-loop op- timality. A case study for an implementation in reconfigurable hardware shows how a designer can optimally trade closed-loop performance with hardware implementation performance

    Power Reduction of Acetic Acid to the Heavy Metal of Blood Cockle (Anadara Granosa)

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    This study aimed to reduce levels of heavy metals contained in the body ofblood cockle (Anadara granosa) with acetic acid soaking method. The experimentaldesign used in this study is a randomized block design (RAK) with 4 levelstreatments, blood cockle without soaking, the addition of 5% acetic acid, 15% and25%. The highest reducing power contained in Pb with 25 % acetic acid soaking, theCu with 5 % acetic acid soaking, the metal Zn with 25 % acetic acid soaking and Cdmetal with 25 % acetic acid soaking. The highest organoleptic assessment containedin such a test is the 25 % acetic acid soaking (16.58), aroma aroma is in control(15.96) and the texture is in control (17.88)

    Consulting a traditional healer and negative illness perceptions are associated with non-adherence to treatment in Indonesian women with breast cancer

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    Objective: The aim of the present study was to test the association between psychosocial factors and delay in uptake of treatment and treatment non-adherence in Indonesian women with breast cancer. Methods: Seventy consecutive patients with breast cancer who were treated at the Hasan Sadikin Hospital in Indonesia were recruited. They completed a demographic form, the non-adherence questionnaire, the Breast Cancer Knowledge Test, the Brief Illness Perception Questionnaire, the Multidimensional Health Locus of Control Scales, the Satisfaction with Cancer Information Profile and the Distress Thermometer. Results: Seventeen (24%) out of 70 patients reported that they had delayed initiating treatment at the hospital, and nine (13%) out of 70 patients had missed two or more consecutive treatment sessions. In the bivariate analyses, we found no significant differences on any of the psychological variables between patients who delayed initiating treatment and those patients who did not, whereas patients who had missed two or more consecutive sessions had lower satisfaction with the type and timing of information provided and more negative illness perceptions than patients who had not missed their sessions. In multivariate regression analyses, consulting a traditional healer before diagnosis was associated with treatment delay (β = 1.27, p = 0.04). More negative illness perceptions (β = 0.10, p = 0.02) and whether a traditional healer had been consulted after diagnosis (β = 1.67, p = 0.03) were associated with missing treatment sessions. Conclusions: Indonesian health professionals need to be aware of patients' negative illness perceptions and their unrealistic belief in traditional healers

    Capillary electrophoretic and extraction conditions for the analysis of Catha edulis FORKS active principles

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    A capillary electrophoretic method, which allowed the detection and separation of the active principles of Catha edulis, i.e. cathinone, cathine and phenylpropanolamine, was developed. A suitable internal standard (nicotinamide), which permitted the quantification of the analytes reducing the variability of the migration times due to EOF changes, was identified. The analytical method was validated, assessing linearity, sensitivity and repeatability, showing optimal features for the analysis of the vegetable material. Moreover extraction conditions were investigated to achieve the exhaustion of the plant material in the fastest and most efficient way to meet the requirements of the Court

    Minimally invasive strategies for the treatment of prostate cancer recurrence after radiation therapy: a systematic review

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    INTRODUCTION: The aim of this review was to conduct a comprehensive analysis of the role of minimally invasive salvage modalities in radio-recurrent prostate cancer and the associated clinical outcomes and toxicity profiles. EVIDENCE ACQUISITION: A systematic review of the current literature was conducted through the Medline and NCBI PubMed, Scopus databases in January 2020. All papers published after 2000, concerning studies conducted on humans for radio-recurrent prostate cancer were considered for the review. EVIDENCE SYNTHESIS: Overall, 545 studies were identified. After duplicate exclusion, initial screening, and eligibility evaluation, a total of 80 studies were included in the qualitative analysis, corresponding to a cohort of 6681 patients. The median age at initial diagnosis ranged from 59 to 75.5. Pre-treatment PSA ranged from 6.2 to 27.4 ng/mL. All patients underwent primary radiotherapy for localized prostate cancer. Cryotherapy, Brachytherapy, EBRT, HIFU were the minimally invasive options mostly used as salvage therapy. They showed to be promising approaches for recurrent prostate cancer (PCa) control, with acceptable toxicities. CONCLUSIONS: Minimally invasive therapeutic options offer promising results in terms of biochemical control in the local recurrence setting. Unfortunately, the absence of high quality and comparative studies makes it difficult to establish which method is the best in terms of oncological and safety outcomes

    A rare case of mycobacterial pseudoaneurysm of the superficial femoral artery

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    Extrapulmonary localization of tuberculosis accounts for about 15-20% of cases. Several cases of Mycobacterium tuberculosis with vascular involvement have been described, but only few cases for limb vessels

    Do oil price forecast disagreement of survey of professional forecasters predict crude oil return volatility?

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    This is the final version. Available on open access from Elsevier via the DOI in this recordThis paper explores whether the dispersion in forecasted crude oil prices from the European Central Bank Survey of Professional Forecasters can provide insights for predicting crude oil return volatility. It is well-documented that higher disagreement among forecasters of asset price implies greater uncertainty and higher return volatility. Using several Generalized Autoregressive Conditional Heteroskedasticity with Mixed Data Sampling (GARCH-MIDAS) models, we find, based on the in-sample estimation results, the oil market experiences greater volatility when the forecasters’ disagreements increase. The model that integrates both historical realized variance and forward-looking forecaster disagreement into the conditional variance, along with the model focusing solely on pure forward-looking forecaster disagreement, exhibits a much superior fit to the data compared to the model relying solely on realized variance and the models considering forward-looking forecasted mean return. The out-of-sample forecasting results unequivocally illustrate that incorporating forecaster disagreement offers valuable insights, markedly enhancing the predictive accuracy of crude oil return volatility within the GARCH-MIDAS model. Moreover, we illustrate the economic benefit of considering forecasters’ disagreement when forecasting volatility, demonstrating its significance for VaR risk management.Jan Wallander and Tom Hedelius Foundation of Handelsbanken, Swede
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