202 research outputs found

    Design Issues and Challenges of File Systems for Flash Memories

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    This chapter discusses how to properly address the issues of using NAND flash memories as mass-memory devices from the native file system standpoint. We hope that the ideas and the solutions proposed in this chapter will be a valuable starting point for designers of NAND flash-based mass-memory devices

    Drift Correction Methods for gas Chemical Sensors in Artificial Olfaction Systems: Techniques and Challenges

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    In this chapter the authors introduce the main challenges faced when developing drift correction techniques and will propose a deep overview of state-of-the-art methodologies that have been proposed in the scientific literature trying to underlying pros and cons of these techniques and focusing on challenges still open and waiting for solution

    Artificial olfaction system for on-site odour measurement

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    Odour impacts and concerns are an impediment to the growth of the Australian chicken meat industry. To manage these, the industry has to be able to demonstrate the efficacy of its odour reduction strategies scientifically and defensibly; however, it currently lacks reliable, cost effective and objective tools to do so. This report describes the development of an artificial olfaction system (AOS) to measure meat chicken farm odour. This report describes the market research undertaken to determine the demand for such a tool, the development and evaluation of three AOS prototypes, data analysis and odour prediction modelling, and the development of two complementary odour measurement tools, namely, a volatile organic compound (VOC) pre-concentrator and a field olfactometer. This report is aimed at investors in poultry odour research and those charged with, or interested in, assessment of odour on chicken farms, including farm managers, integrators, their consultants, regulators and researchers. The findings will influence the focus of future environmental odour measurement research

    Increasing pattern recognition accuracy for chemical sensing by evolutionary based drift compensation

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    Artificial olfaction systems, which mimic human olfaction by using arrays of gas chemical sensors combined with pattern recognition methods, represent a potentially low-cost tool in many areas of industry such as perfumery, food and drink production, clinical diagnosis, health and safety, environmental monitoring and process control. However, successful applications of these systems are still largely limited to specialized laboratories. Sensor drift, i.e., the lack of a sensor's stability over time, still limits real in dustrial setups. This paper presents and discusses an evolutionary based adaptive drift-correction method designed to work with state-of-the-art classification systems. The proposed approach exploits a cutting-edge evolutionary strategy to iteratively tweak the coefficients of a linear transformation which can transparently correct raw sensors' measures thus mitigating the negative effects of the drift. The method learns the optimal correction strategy without the use of models or other hypotheses on the behavior of the physical chemical sensors

    An embodied and grounded perspective on concepts

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    By the mainstream view in psychology and neuroscience, concepts are informational units, rather stable, and are represented in propositional format. In the view I will outline, instead, concepts correspond to patterns of activation of the perception, action and emotional systems which are typically activated when we interact with the entities they refer to. Starting from this embodied and grounded approach to concepts, I will focus on different research lines and present some experimental evidence concerning concepts of objects, concepts of actions, and abstract concepts. I will argue that, in order to account for abstract concepts, embodied and grounded theories should be extended

    Non–contact real–time detection of trace nitro-explosives by MOF composites visible–light chemiresistor

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    To create an artificial structure to remarkably surpass the sensitivity, selectivity and speed of the olfaction system of animals is still a daunting challenge. Herein, we propose a core-sheath pillar (CSP) architecture with a perfect synergistic interface that effectively integrates the advantages of metal–organic frameworks and metal oxides to tackle the above-mentioned challenge. The sheath material, NH₂-MIL-125, can concentrate target analyte, nitro-explosives, by 10¹² times from its vapour. The perfect band-matched synergistic interface enables the TiO₂ core to effectively harvest and utilize visible light. At room temperature and under visible light, CSP (TiO₂, NH₂-MIL-125) shows an unexpected self-promoting analyte-sensing behaviour. Its experimentally reached limit of detection (~0.8 ppq, hexogeon) is 10³ times lower than the lowest one achieved by a sniffer dog or all sensing techniques without analyte pre-concentration. Moreover, the sensor exhibits excellent selectivity against commonly existing interferences, with a short response time of 0.14 min

    An end-user platform for FPGA-based design and rapid prototyping of feedforward artificial neural networks with on-chip backpropagation learning

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    The hardware implementation of an artificial neural network (ANN) using field-programmable gate arrays (FPGAs) is a research field that has attracted much interest and attention. With the developments made, the programmer is now forced to face various challenges, such as the need to master various complex hardware-software development platforms, hardware description languages, and advanced ANN knowledge. Moreover, such an implementation is very time consuming. To address these challenges, this paper presents a novel neural design methodology using a holistic modeling approach. Based on the end-user programming concept, the presented solution empowers end users by means of abstracting the low-level hardware functionalities, streamlining the FPGA design process and supporting rapid ANN prototyping. A case study of an ANN as a pattern recognition module of an artificial olfaction system trained to identify four coffee brands is presented. The recognition rate versus training data features and data representation was analyzed extensively

    Summarised findings from Australian poultry odour research (2005–2018)

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    D&E related to odour is integral to addressing community concerns, reducing the potential for odour impacts and supporting sustainable growth of the chicken meat industry. By necessity, the industry is typically established on the urban fringe, which increases the potential for amenity impacts. Odour RD&E has involved several research teams, including government agencies, universities, and consultancy businesses. The industry must now undertake the important tasks of broadly reviewing the overall knowledge that has been developed to date, taking stock of the achievements and challenges, and planning the path forward to address emerging and unresolved issues. This project summarises the odour-related RD&E that has been supported by the Australian chicken meat industry (through AgriFutures Australia or the Poultry CRC) since 2005. It was funded by industry revenue, the Australian Government, and the Queensland Government Department of Agriculture and Fisheries

    Rapid continuous chemical analysis of meat chicken shed emissions by SIFT–MS

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    Assessing and addressing odour impacts from poultry production is extremely difficult and subjective because the odorants involved and their dynamics over time and space are poorly understood. This knowledge gap is due, in part, to the lack of suitable analytical tools for measuring and monitoring odorants in the field. The emergence of Selected Ion Flow Tube – Mass Spectrometry (SIFT–MS) and similar instruments is changing that. These tools can rapidly quantify targeted odorants in ambient air in real time, even at very low concentrations. Such data is essential for developing better odour abatement strategies, assessment methods and odour dispersion models. This project trialled a SIFT–MS to determine its suitability for assessing the odorants in meat chicken shed emissions over time and space. This report details evaluations in New Zealand and Australia to determine the potential of SIFT–MS as a tool for the chicken meat industry, including odour measurement (as a proxy for dynamic olfactometry). The report is specifically targeted at those funding and conducting poultry odour research. It will be of interest to those involved with environmental odour monitoring and assessment in general. The high upfront cost of SIFT–MS will lead to potential users wanting compelling evidence that SIFT–MS will meet their needs before they invest in one

    A Review of the Repellency Properties of Pyrethrins

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    Pyrethrum is an insecticide created from the dried flower heads of plants in the genus Chrysanthemum. The six compounds responsible for the insecticidal activity are collectively known as pyrethrins, and are known individually as Pyrethrin-I, Pyrethrin-II, Cinerin-I, Cinerin-II, Jasmolin-I, and Jasmolin-II. Of these compounds, Pyrethrin-I is best known for mortality, and Pyrethrin-II is best known for knockdown activity (Sisay et al. 2001). These compounds are voltage gated sodium-ion channel disruptors acting on nerve cells. The inside of nerve cells is negative relative to the outside at rest. It is due to an imbalance between ions on either side of the cell membrane, creating a membrane potential, I.E. a high level of potassium and a low level of sodium inside the cell and more sodium than potassium outside the cell, and internally higher concentration of non-diffusible anions. When an action potential occurs after a stimulus, the membrane potential is temporarily reversed, allowing for sodium ions to enter the nerve cell through voltage-gated sodium channels and causing the nerve to fire. The level of sodium then begins to decrease, and potassium increases by active transport (K+/Na+ pump), returning to the ion concentrations of the cell’s resting level after a brief hyperpolarization. Pyrethrins work by prolonging the open state of the voltage gated sodium channel, leading to paralysis (knockdown) and eventually mortality (Narahashi, T. 1971). If the concentration of pyrethrum is not high enough to cause knockdown, the insect can potentially leave the treated area (repellency) after experiencing sublethal effects. Pyrethrins are also known to be relatively harmless to mammals, especially when compared to other plant-based compounds (Maia and Moore 2011). It has an LD50 value of 1,200 to 1,500 mg/kg in rats. Nicotine by comparison has an LD50 value of 50 to 60 mg/kg in rats (Ware, G.W. 2000). This review looks at the history and importance of pyrethrum as a repellent, test methods used to understand repellency, as well as the mechanisms responsible for causing an insect to be repelled. It focuses on urban and medical pests and the efficacy against them, as these pests tend to be disease vectors, or mechanical transmitters of disease, and have the highest need to be repelled
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