Physical configuration-based feedforward active noise control using adaptive second-order truncated Volterra filter

This paper presents a physical configuration-based feedforward active noise control scheme with an adaptive second-order truncated Volterra filter for point source cancellation in three-dimensional free-field acoustic environment. The inertial particle swarm optimization (PSO) algorithm is used as the parameter adjustment mechanism for tuning the coefficients of the adaptive Volterra filter. The first motivation of this paper is to provide a precise description of the relationship between the degree of cancellation and the physical distances between system components. The second motivation is to improve the cancellation performance in the presence of nonlinearities with the adaptive Volterra filter in light of the characteristics of sensing microphone and actuating loudspeaker. The reason for choosing the inertial PSO algorithm is that it can avoid the trap of local optima. The work thus presented makes two main contributions. The first is using the degree of cancellation as a function of the physical distances between system components to provide a quantitative analysis of system performance. The second is the application of the adaptive Volterra filter, which achieves improvements in the cancellation performance of the system under different physical configurations with a reasonable compromise with complexity. For consistency with the numerical analysis, several simulation experiments are conducted using MATLAB/Simulink

No Leverage Without Authority? Comparing the Effectiveness of International Organizations Across GLOBE Issue Areas

Do International Organizations (IOs) actually help address global problems? This question is of major concern for global governance scholars and policymakers, yet few existing studies review issues of effectiveness across a range of different issue areas. This report generates comparative insights on IO performance across all the domains included in the GLOBE project, namely climate change, development, finance, investment, migration, security, and trade. Based on a detailed GLOBE expert survey, we consider how key IOs in these issue areas perform across three different measures of effectiveness: constitutive effectiveness, compliance, and goal achievement. We also investigate causal claims on effectiveness, exploring how IO institutional design – and in particular measures of authority – influence their ability to shape policy outcomes. Taking stock of the distribution of authority across issue areas and policy functions, we ask whether highly formalized, deeply constraining institutional arrangements have a consistently stronger impact on state behavior or whether less formalized institutions with fewer discretionary powers can also contribute to the effective implementation of internationally coordinated policies. Finally, we identify key cross-cutting challenges for global governance effectiveness, including political conflict and politicization, concerns related to legitimacy and representation, and growing problem complexity

Indoor Localization of Mobile Robots with Wireless Sensor Network Based on Ultra Wideband using Experimental Measurements of Time Difference of Arrival

This paper presents investigations into wireless localization techniques for mobile robots operating in indoor environments. Localization systems can guide robots to perform different tasks such as monitoring children or elderly people, aid mobility of the visually impaired and localize mobile objects or packages in warehouses. They are essential for localization of robots operating in re-mote places that are inaccessible or hazardous to humans. Currently, ultra wide band (UWB) in indoor environments provides an accuracy of 24 mm under line of sight (LOS) or non-line of sight (NLOS) conditions in a working range of 160 m indoors. The work presented in this paper carries out experimental validation of localization algorithms using mobile robots and UWB signals. These are measured in LOS and NLOS environments. The measurements are performed with the UWB radio PulsON 410 (P410) and mobile robots (AmigoBot) with maximum travel-ling speed of 1 m/s and equipped with an on-board computer, sonar, odometer, camera and inertial navigation system. Experimental results obtained for the system show positioning errors of less than 55 mm

Fuzzy logic feedforward active noise control with distance ratio and acoustic feedback using Takagi–Sugeon–Kang inference

© The Author(s) 2019. Noise, as undesired sound, severely affects the quality of human life. Currently, active noise control method has demonstrated its capability in low-frequency noise cancellation and the advance in saving money and reducing weight and volume of related materials used in the passive noise control technology. The widespread configuration for active noise control technology is finite impulse response filter with filtered-x least mean squares (FxLMS) algorithm. However, the nonlinearities in the secondary path, which mainly arise from sensors, actuators and amplifiers used in the active noise control system, will cause instability and degrade the performance while using the FxLMS algorithm. In order to cope with this challenge, many new approaches have been proposed and fuzzy logic control is one of these. In this paper, a Takagi–Sugeon–Kang-type fuzzy logic control-based feedforward active noise control system with focus on the geometry configuration is introduced. In contrast to previous work, all physical paths are modelled by pure time delay transfer function and the acoustic feedback is added as part of inputs for the fuzzy logic control. Computational experiments are implemented within the Matlab/Simulink platform, and several case studies are presented with time and frequency domain analyses to demonstrate the cancellation ability of the proposed feedforward active noise control system and investigate the influence of distance ratio on the overall noise cancellation performance

Simulated tests of feedforward active noise control (ANC) for building noise cancellation

This student paper presents an understanding of Active Noise Control (ANC) systems especially focus on the physical geometry about the detector and the observer and develops a series of simulation experiments for the different type of signal to test the cancellation performance using feedforward active noise control procedure with the fixed controller proposed by Tokhi and Leitch in 1987. This study will provide a further demonstration for the control approach and a foundation for proposing new ANC algo-rithms in the future studies

Use of clinical guidelines: Perspectives from clinicians in paediatric and maternity hospitals in Kabul, Afghanistan

© 2015, World Health Organization. All rights reserved. This study explored the perceived value, role and reported use of clinical guidelines by clinicians in urban paediatric and maternity hospital settings, and the effect of current implementation strategies on clinician attitudes, knowledge and behaviour. A total of 63 clinicians from 7 paediatric and maternity hospitals in Kabul, Afghanistan participated in structured focus groups; content analysis methodology was used for identification and analysis of key themes. Seven sets of guidelines, protocols or standards were identified (including 5 WHO-endorsed guidelines). However, most are failing to achieve high levels of use. Factors associated with guideline use included: clinician involvement in guideline development; multidisciplinary training; demonstrable results; and positive clinician perceptions regarding guideline quality and contextual appropriateness. Implementation activities should fulfil 3 major objectives: promote guideline awareness and access; stimulate motivation among clinical guideline users; and actively facilitate adherence to guidelines

Hybrid spiral-dynamic bacteria-chemotaxis algorithm with application to control two-wheeled machines

This paper presents the implementation of the hybrid spiral-dynamic bacteria-chemotaxis (HSDBC) approach to control two different configurations of a two-wheeled vehicle. The HSDBC is a combination of bacterial chemotaxis used in bacterial forging algorithm (BFA) and the spiral-dynamic algorithm (SDA). BFA provides a good exploration strategy due to the chemotaxis approach. However, it endures an oscillation problem near the end of the search process when using a large step size. Conversely; for a small step size, it affords better exploitation and accuracy with slower convergence. SDA provides better stability when approaching an optimum point and has faster convergence speed. This may cause the search agents to get trapped into local optima which results in low accurate solution. HSDBC exploits the chemotactic strategy of BFA and fitness accuracy and convergence speed of SDA so as to overcome the problems associated with both the SDA and BFA algorithms alone. The HSDBC thus developed is evaluated in optimizing the performance and energy consumption of two highly nonlinear platforms, namely single and double inverted pendulum-like vehicles with an extended rod. Comparative results with BFA and SDA show that the proposed algorithm is able to result in better performance of the highly nonlinear systems

A connectome of the adult drosophila central brain

The neural circuits responsible for behavior remain largely unknown. Previous efforts have reconstructed the complete circuits of small animals, with hundreds of neurons, and selected circuits for larger animals. Here we (the FlyEM project at Janelia and collaborators at Google) summarize new methods and present the complete circuitry of a large fraction of the brain of a much more complex animal, the fruit fly Drosophila melanogaster. Improved methods include new procedures to prepare, image, align, segment, find synapses, and proofread such large data sets; new methods that define cell types based on connectivity in addition to morphology; and new methods to simplify access to a large and evolving data set. From the resulting data we derive a better definition of computational compartments and their connections; an exhaustive atlas of cell examples and types, many of them novel; detailed circuits for most of the central brain; and exploration of the statistics and structure of different brain compartments, and the brain as a whole. We make the data public, with a web site and resources specifically designed to make it easy to explore, for all levels of expertise from the expert to the merely curious. The public availability of these data, and the simplified means to access it, dramatically reduces the effort needed to answer typical circuit questions, such as the identity of upstream and downstream neural partners, the circuitry of brain regions, and to link the neurons defined by our analysis with genetic reagents that can be used to study their functions. Note: In the next few weeks, we will release a series of papers with more involved discussions. One paper will detail the hemibrain reconstruction with more extensive analysis and interpretation made possible by this dense connectome. Another paper will explore the central complex, a brain region involved in navigation, motor control, and sleep. A final paper will present insights from the mushroom body, a center of multimodal associative learning in the fly brain

A connectome and analysis of the adult Drosophila central brain

The neural circuits responsible for animal behavior remain largely unknown. We summarize new methods and present the circuitry of a large fraction of the brain of the fruit fly Drosophila melanogaster. Improved methods include new procedures to prepare, image, align, segment, find synapses in, and proofread such large data sets. We define cell types, refine computational compartments, and provide an exhaustive atlas of cell examples and types, many of them novel. We provide detailed circuits consisting of neurons and their chemical synapses for most of the central brain. We make the data public and simplify access, reducing the effort needed to answer circuit questions, and provide procedures linking the neurons defined by our analysis with genetic reagents. Biologically, we examine distributions of connection strengths, neural motifs on different scales, electrical consequences of compartmentalization, and evidence that maximizing packing density is an important criterion in the evolution of the fly’s brain

Type II Heat-Labile Enterotoxins from 50 Diverse Escherichia coli Isolates Belong Almost Exclusively to the LT-IIc Family and May Be Prophage Encoded

Some enterotoxigenic Escherichia coli (ETEC) produce a type II heat-labile enterotoxin (LT-II) that activates adenylate cyclase in susceptible cells but is not neutralized by antisera against cholera toxin or type I heat-labile enterotoxin (LT-I). LT-I variants encoded by plasmids in ETEC from humans and pigs have amino acid sequences that are ≥95% identical. In contrast, LT-II toxins are chromosomally encoded and are much more diverse. Early studies characterized LT-IIa and LT-IIb variants, but a novel LT-IIc was reported recently. Here we characterized the LT-II encoding loci from 48 additional ETEC isolates. Two encoded LT-IIa, none encoded LT-IIb, and 46 encoded highly related variants of LT-IIc. Phylogenetic analysis indicated that the predicted LT-IIc toxins encoded by these loci could be assigned to 6 subgroups. The loci corresponding to individual toxins within each subgroup had DNA sequences that were more than 99% identical. The LT-IIc subgroups appear to have arisen by multiple recombinational events between progenitor loci encoding LT-IIc1- and LT-IIc3-like variants. All loci from representative isolates encoding the LT-IIa, LT-IIb, and each subgroup of LT-IIc enterotoxins are preceded by highly-related genes that are between 80 and 93% identical to predicted phage lysozyme genes. DNA sequences immediately following the B genes differ considerably between toxin subgroups, but all are most closely related to genomic sequences found in predicted prophages. Together these data suggest that the LT-II loci are inserted into lambdoid type prophages that may or may not be infectious. These findings raise the possibility that production of LT-II enterotoxins by ETEC may be determined by phage conversion and may be activated by induction of prophage, in a manner similar to control of production of Shiga-like toxins by converting phages in isolates of enterohemmorhagic E. coli