261 research outputs found
Metasearch: Data Fusion for Document Retrieval
The metasearch problem is to optimally merge the ranked lists output by an arbitrary number of search systems into one ranked list. In this work: (1) We show that metasearch improves upon not just the raw performance of the input search engines, but also upon the consistency of the input search engines from query to query. (2) We experimentally prove that simply weighting input systems by their average performance can dramatically improve fusion results. (3) We show that score normalization is an important component of a metasearch engine, and that dependence upon statistical outliers appears to be the problem with the standard technique. (4) We propose a Bayesian model for metasearch that outperforms the best input system on average and has performance competetive with standard techniques. (5) We introduce the use of Social Choice Theory to the metasearch problem, modeling metasearch as a democratic election. We adapt a positional voting algorithm, the Borda Count, to create a metasearch algorithm, acheiving reasonable performance. (6) We propose a metasearch model adapted from a majoritarian voting procedure, the Condorcet algorithm. The resulting algorithm is the best performing algorithm in a number of situations. (7) We propose three upper bounds for the problem, each bounding a different class of algorithms. We present experimental results for each algorithm using two types of experiments on each of four data sets
Hey, You Got Your Language In My Operating System!
Several projects in the operating systems research community suggest a trend of convergence among features once divided between operating systems and languages. We describe how partial evaluation and transformational programming systems apply to this trend by providing a general framework for application support, from compilation to run-time services. We contend that the community will no longer think of implementing a static collection of services and calling it an operating system; instead, this general framework will allow applications to be flexibly configured, and the ``operating system\u27\u27 will simply be the application support that is supplied at run-time
Optimisation of Cleaning Detergent use in Brewery Fermenter Cleaning
This paper investigates improvement possibilities in the cleaning operations undertaken at an industrial brewery. Experiments were performed on a bench scale cleaning rig which was designed to simulate ‘real life’ cleaning conditions of a clean-in-place (CIP) set in the brewery. The rig was used to clean consistently fouled coupons using difficult soils from the brewery. The objective of the experiments was to determine the reduction in effective cleaning performance with varied levels of Na2CO3 in the detergent from NaOH degradation and the maximum level that may be present before cleaning quality is impacted. The shear force of the cleaning fluid across the surface of the coupon was also varied to determine the impact on cleaning performance. Data collected from these offline measurements has been used to predict the end point of the detergent usage based on cost optimisation within the empirically determined limits. The results show that the NaOH detergent usage can be extended while achieving the same time to clean without impacting the cleaning quality and preventing premature disposal. This will provide an increased confidence level when cleaning fermenters with NaOH. It will also reduce cleaning costs and benefit the environment by reducing chemical effluent and minimising water consumption
Bayes Optimal Metasearch: A Probabilistic Model for Combining the Results of Multiple Retrieval Systems
We introduce a new, probabilistic model for combining the outputs of an arbitrary number of query retrieval systems. By gathering simple statistics on the average performance of a given set of query retrieval systems, we construct a Bayes optimal mechanism for combining the outputs of these systems. Our construction yields a metasearch strategy whose empirical performance nearly always exceeds the performance of any of the constituent systems. Our construction is also robust in the sense that if ``good\u27\u27 and ``bad\u27\u27 systems are combined, the performance of the composite is still on par with, or exceeds, that of the best constituent system. Finally, our model and theory provide theoretical and empirical avenues for the improvement of this metasearch strategy
Ubiquitous text interaction
Computer-based interactions increasingly pervade our everyday environments. Be it on a mobile device, a wearable device, a wall-sized display, or an augmented reality device, interactive systems often rely on the consumption, composition, and manipulation of text. The focus of this workshop is on exploring the problems and opportunities of text interactions that are embedded in our environments, available all the time, and used by people who may be constrained by device, situation, or disability. This workshop welcomes all researchers interested in interactive systems that rely on text input or output. Participants should submit a short position statement outlining their background, past work, future plans, and suggesting a use-case they would like to explore in-depth during the workshop. During the workshop, small teams will form around common or compelling use-cases. Teams will spend time brainstorming, creating low-fidelity prototypes, and discussing their use-case with the group. Participants may optionally submit a technical paper for presentation as part of the workshop program. The workshop serves to sustain and build the community of text entry researchers who attend CHI. It provides an opportunity for new members to join this community, soliciting feedback from experts in a small and supportive environment
High-Temperature, High-Load-Capacity Radial Magnetic Bearing
A radial heteropolar magnetic bearing capable of operating at a temperature as high as 1,000 F (=540 C) has been developed. This is a prototype of bearings for use in gas turbine engines operating at temperatures and speeds much higher than can be withstood by lubricated rolling-element bearings. It is possible to increase the maximum allowable operating temperatures and speeds of rolling-element bearings by use of cooling-air systems, sophisticated lubrication systems, and rotor-vibration- damping systems that are subsystems of the lubrication systems, but such systems and subsystems are troublesome. In contrast, a properly designed radial magnetic bearing can suspend a rotor without contact, and, hence, without need for lubrication or for cooling. Moreover, a magnetic bearing eliminates the need for a separate damping system, inasmuch as a damping function is typically an integral part of the design of the control system of a magnetic bearing. The present high-temperature radial heteropolar magnetic bearing has a unique combination of four features that contribute to its suitability for the intended application: 1. The wires in its electromagnet coils are covered with an insulating material that does not undergo dielectric breakdown at high temperature and is pliable enough to enable the winding of the wires to small radii. 2. The processes used in winding and potting of the coils yields a packing factor close to 0.7 . a relatively high value that helps in maximizing the magnetic fields generated by the coils for a given supplied current. These processes also make the coils structurally robust. 3. The electromagnets are of a modular C-core design that enables replacement of components and semiautomated winding of coils. 4. The stator is mounted in such a manner as to provide stable support under radial and axial thermal expansion and under a load as large as 1,000 lb (.4.4 kN)
In vitro evidence consistent with an interaction between wild‐type and mutant SOD1 protein associated with canine degenerative myelopathy
Canine degenerative myelopathy (DM) is a progressive neurological disorder that may be considered to be a large animal model for specific forms of the fatal human disease, familial amyotrophic lateral sclerosis (fALS). DM is associated with a c118G>A mutation of the superoxide dismutase 1 (Sod1) gene, and a significant proportion of cases are inherited in an autosomal recessive manner in contrast to the largely, but not exclusively, dominant mode of inheritance in fALS. The consensus view is that these Sod1/SOD1 mutations result in a toxic gain of function but the mechanisms remain unclear. Here we used an in vitro neuroblastoma cell line transfection system to monitor wild-type and mutant forms of SOD1 fusion proteins containing either a Cherry or an enhanced green fluorescent protein (EGFP) tag. These fusion proteins retained SOD1 enzymatic activity on a native gel assay system. We demonstrate that SOD1 aggregate density is significantly higher in DM transfectants compared to wild-type. In addition, we show by co-immunoprecipitation and confocal microscopy, evidence for a potential interaction between wild-type and mutant forms of SOD1 in co-transfected cells. While in vitro studies have shown SOD1 heterodimer formation in fALS models, this is the first report for DM SOD1. Therefore, despite for the majority of cases there is a difference in the mode of inheritance between fALS and DM, a similar interaction between wild-type and mutant SOD1 forms can occur. Clarifying the role of SOD1 in DM may also be of benefit to understanding the role of SOD1 in fALS
Alkaline phosphatase in nasal secretion of cattle: biochemical and molecular characterisation
BACKGROUND: Nasal secretion (NS) was investigated as a source of information regarding the mucosal and systemic immune status of cattle challenged by respiratory disease. A method for the collection of substantial volumes (~12 ml) of NS from cattle was developed to establish a reference range of analytes that are present in the NS of healthy cattle. Biochemical profiles of NS from a group of 38 healthy Holstein-Friesian cows revealed high alkaline phosphatase (AP) activity of up to 2392 IU/L. The character and source of the high activity of AP in bovine NS was investigated. RESULTS: Histochemical analysis confirmed the localization of the AP enzyme activity to epithelial cells and serous glands of the nasal respiratory mucosa. Analysis of mRNA levels from nasal mucosa by end point RT-PCR and PCR product sequencing confirmed that the AP was locally produced and is identical at the nucleotide level to the non-specific AP splice variant found in bovine liver, bone and kidney. Analysis by isoelectric focussing confirmed that AP was produced locally at a high level in nasal epithelium demonstrating that AP from nasal secretion and nasal mucosa had similar pI bands, though differing from those of the liver, kidney, bone and intestine, suggesting different post-translational modification (PTM) of AP in these tissues. CONCLUSIONS: A nasal isozyme of AP has been identified that is present at a high activity in NS, resulting from local production and showing distinctive PTM and may be active in NS as an anti-endotoxin mediator
Willingness of the UK public to volunteer for testing in relation to the COVID-19 pandemic
BACKGROUND: The World Health Organization declared the rapid spread of COVID-19 around the world to be a global public health emergency. The spread of the disease is influenced by people’s willingness to adopt preventative public health behaviours, such as participation in testing programmes, and risk perception can be an important determinant of engagement in such behaviours. METHODS: In this study, we present the first assessment during the first wave of the pandemic and the early stages of the first UK lockdown in April & May 2020 of how the UK public (N = 778) perceived the usefulness of testing for coronavirus and the factors that influence a person’s willingness to test for coronavirus. RESULTS: None of the key demographic characteristics (age, gender, education, disability, vulnerability status, or professional expertise) were significantly related to the respondents’ willingness to be tested for coronavirus. However, closely following the news media was positively related to willingness to be tested. Knowledge and perceptions about coronavirus significantly predicted willingness to test, with three significantly contributing factors: worry about the health and social impacts to self and family; personal susceptibility; and concerns about the impacts of coronavirus on specific demographic groups. Views on testing for coronavirus predicted willingness to test, with the most influential factors being importance of testing by need; negative views about widespread testing; and mistrust in doctor’s advice about testing. CONCLUSIONS: Implications for effective risk communication and localised public health approaches to encouraging public to put themselves forward for testing are discussed. We strongly advocate for effective communications and localised intervention by public health authorities, using media outlets to ensure that members of the public get tested for SARs-CoV2 when required. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-022-12848-z
Reinforcement Learning with Autonomous Small Unmanned Aerial Vehicles in Cluttered Environments
We present ongoing work in the Autonomy Incubator at NASA Langley Research Center (LaRC) exploring the efficacy of a data set aggregation approach to reinforcement learning for small unmanned aerial vehicle (sUAV) flight in dense and cluttered environments with reactive obstacle avoidance. The goal is to learn an autonomous flight model using training experiences from a human piloting a sUAV around static obstacles. The training approach uses video data from a forward-facing camera that records the human pilot's flight. Various computer vision based features are extracted from the video relating to edge and gradient information. The recorded human-controlled inputs are used to train an autonomous control model that correlates the extracted feature vector to a yaw command. As part of the reinforcement learning approach, the autonomous control model is iteratively updated with feedback from a human agent who corrects undesired model output. This data driven approach to autonomous obstacle avoidance is explored for simulated forest environments furthering autonomous flight under the tree canopy research. This enables flight in previously inaccessible environments which are of interest to NASA researchers in Earth and Atmospheric sciences
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