51 research outputs found

    Adaptive System Identification using Markov Chain Monte Carlo

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    One of the major problems in adaptive filtering is the problem of system identification. It has been studied extensively due to its immense practical importance in a variety of fields. The underlying goal is to identify the impulse response of an unknown system. This is accomplished by placing a known system in parallel and feeding both systems with the same input. Due to initial disparity in their impulse responses, an error is generated between their outputs. This error is set to tune the impulse response of known system in a way that every change in impulse response reduces the magnitude of prospective error. This process is repeated until the error becomes negligible and the responses of both systems match. To specifically minimize the error, numerous adaptive algorithms are available. They are noteworthy either for their low computational complexity or high convergence speed. Recently, a method, known as Markov Chain Monte Carlo (MCMC), has gained much attention due to its remarkably low computational complexity. But despite this colossal advantage, properties of MCMC method have not been investigated for adaptive system identification problem. This article bridges this gap by providing a complete treatment of MCMC method in the aforementioned context

    A New Approach to Linear Estimation Problem in Multi-user Massive MIMO Systems

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    A novel approach for solving linear estimation problem in multi-user massive MIMO systems is proposed. In this approach, the difficulty of matrix inversion is attributed to the incomplete definition of the dot product. The general definition of dot product implies that the columns of channel matrix are always orthogonal whereas, in practice, they may be not. If the latter information can be incorporated into dot product, then the unknowns can be directly computed from projections without inverting the channel matrix. By doing so, the proposed method is able to achieve an exact solution with a 25% reduction in computational complexity as compared to the QR method. Proposed method is stable, offers an extra flexibility of computing any single unknown, and can be implemented in just twelve lines of code

    Microwave-assisted solvent free efficient synthesis of 1,3,4-oxadiazole-2(3H)-thiones and their potent in vitro urease inhibition activity

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    An efficient solvent free microwave assisted synthesis of 5-substituted-1,3,4-oxadiazole-2(3H)-thiones (2a-2r) from hydrazides and carbon disulfide has been accomplished in good to excellent yield. The urease inhibition activity of the resulting compounds was investigated. Preliminary bioassay indicated that the compound 2j bearing 2-bromo substituent is the most active inhibitor exhibiting IC50 12.60 ± 0.92 μM

    An annotated checklist of Coccinellidae with four new records from Pakistan (Coleoptera, Coccinellidae)

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    Some new ladybird (Coleoptera: Coccinellidae) records collected during the last four years across Sindh are reported. A first preliminary checklist of ladybirds from Sindh is presented, consisting of one subfamily, ten tribes, 21 genera, and 29 species including four new records, namely Bulaea lichatschovii (Hummel), Exochomus pubescens Küster, Scymnus (Pullus) latemaculatus Motschulsky, Scymnus (Pullus) syriacus Marseul, and four varieties of the species Cheilomenes sexmaculatus (Fabricius)

    A Short History of Evolution of Indigenous Plants and Medicine System

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    The importance of plants is well known to us. Life and its growth cannot be imagined without plants. Food for our survival is produced by plants and they also create a healthy and eco-friendly environment to live (Sazada et al., 2009).The use of various parts of different medicinal plants to cure specific ailments has been common from ancient times in India. The indigenous system of medicine namely Ayurvedic, Siddha and Unani have been in existence for many centuries. Apart from India, these systems are also prominent in Korea, China, Singapore, West Asia and many other countries. The knowledge of medicinal plants has been inherited traditionally therefore; the utilization of this knowledge has become important for human existence. In the old times, plants were used as remedies for the diseases. The oldest religious book of the World “Rigveda” provides information about the medicinal use of plant “Soma” as a medicinal agent by the Indo-Aryans, which was written between 4000 and 1600 B.C. (Bhattacharjee, 2004).The plant “Soma” is considered to have intoxicating characteristics. This plant is used for sacrificial objectives by Aryans and they also identified its juice as a stimulating beverage (Steiner, 1986). The Aryans also played a vital role in the presentation of therapeutical properties of other medicinal herbs and plants. The knowledge of Aryans about a large number of medicinal plants is demonstrated by the work of Charaka and Sushruta (Kirtikar, 1958).The ancient Indian literature is helpful in driving the current knowledge of using cinchona in malaria, digitalis, strophanthus and physostigma in heart diseases and of quassia as a bitter tonic. The indigenous system of medicine in the Indian sub-continent known as Ayurveda goes back to 700 B.C. and its systematization is attributed mostly to Charaka and Sushruta who have cited about 700 medicinal plants. The book “Sushruta Samhita” compiled in 1000 B.C. includes a comprehensive chapter on herbal therapeutics and contains remarkable information about the use of medicinal plants (Singh and Abrar, 1990)

    Carbon nanotubes incorporated Z-scheme assembly of AgBr/TiO2 for photocatalytic hydrogen production under visible light irradiations

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    Photocatalytic H2 production is a promising strategy toward green energy and alternative to carbon-based fuels which are the root cause of global warming and pollution. In this study, carbon nanotubes (CNTs) incorporated Z-scheme assembly of AgBr/TiO2 was developed for photocatalytic H2 production under visible light irradiations. Synthesized photocatalysts were characterized through transmission electron microscope (TEM), X-ray photoelectron spectra (XPS), X-ray diffractometer (XRD), Fourier transform infrared (FTIR), photoluminescence spectra (PL), Brunauer Emmet-Teller(BET), and UV-vis spectroscopy analysis techniques. The composite photocatalysts exhibited a H2 production of 477 ppm which was three-folds higher than that produced by TiO2. The good performance was attributed to the strong interaction of three components and the reduced charge recombination, which was 89 and 56.3 times lower than the TiO2 and AgBr/TiO2. Furthermore, the role of surface acidic and basic groups was assessed and the photocatalytic results demonstrated the importance of surface functional groups. In addition, the composites exhibited stability and reusability for five consecutive cycles of reaction. Thus, improved performance of the photocatalyst was credited to the CNTs as an electron mediator, surface functional groups, higher surface area, enhanced charge separation and extended visible light absorption edge. This work provides new development of Z-scheme photocatalysts for sustainable H2 production

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
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