9 research outputs found

    Review of Human Vision Facts

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    Work reported herein was conducted at the Artificial Intelligence Laboratory, a Massachusetts Institute of Technology research program supported in part by the Advanced Research Projects Agency of the Department of Defense and monitored by the Office of Naval Research under Contract Number N00014-70-A-0362-0005. Vision Flashes are informal papers intended for internal use.This note is a collection of well known interesting facts about human vision. All parameters are approximate. Some may be wrong. There are sections on retina physiology, eye optics, light adaptation, psychological curios, color and eyeball movement.MIT Artificial Intelligence Laboratory Robotics Section Department of Defense Advanced Research Projects Agenc

    BlueDBM: An Appliance for Big Data Analytics

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    Complex data queries, because of their need for random accesses, have proven to be slow unless all the data can be accommodated in DRAM. There are many domains, such as genomics, geological data and daily twitter feeds where the datasets of interest are 5TB to 20 TB. For such a dataset, one would need a cluster with 100 servers, each with 128GB to 256GBs of DRAM, to accommodate all the data in DRAM. On the other hand, such datasets could be stored easily in the flash memory of a rack-sized cluster. Flash storage has much better random access performance than hard disks, which makes it desirable for analytics workloads. In this paper we present BlueDBM, a new system architecture which has flash-based storage with in-store processing capability and a low-latency high-throughput inter-controller network. We show that BlueDBM outperforms a flash-based system without these features by a factor of 10 for some important applications. While the performance of a ram-cloud system falls sharply even if only 5%~10% of the references are to the secondary storage, this sharp performance degradation is not an issue in BlueDBM. BlueDBM presents an attractive point in the cost-performance trade-off for Big Data analytics.Quanta Computer (Firm)Samsung (Firm)Lincoln Laboratory (PO7000261350)Intel Corporatio

    Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.

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    BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment

    A Proxy-Based Architecture for Secure Networked Wearable Devices

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    We describe the software and hardware architecture for a wearable communicator, and a secure protocol for communication between it and its software proxy. The proxy runs on a fast computer so it is capable of implementing sophisticated cryptographic algorithms, while the wearable communicator contains a simple embedded processor capable of only simple algorithms. The architecture of the wearable communicator is generic, so the same design can be used as a device controller for automation purposes. A prototype automation system using the wearable communicator has been constructed and evaluated. A variety of applications have been implemented on the system including private and public messaging throughout a building, where the messages can be text, audio, or still images. We present an evaluation of our system using scalability, energy and other metrics

    Heterogeneous wireless network management

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    low-power, wireless, network, management Today's wireless networks are highly heterogeneous, with mobile devices consisting of multiple wireless network interfaces (WNICs). Since battery lifetime is limited, power management of the interfaces has become essential. We develop an integrated approach for the management of power and performance of mobile devices in heterogeneous wireless environments. Our policy decides which WNIC to employ for a given application and optimizes its usage based on the current power and performance needs of the system. The policy dynamically switches between WNICs during program execution if data communication requirements and/or network conditions change. We have experimentally characterized Bluetooth and 802.11b wireless interfaces. Our policy has been implemented on HP's IPAQ portable device communicating with HP's HotSpot server [14]. The applications we tested range from MPEG video to email. The results show that our policy offers a large improvement in power savings as compared to singly using 802.11b or Bluetooth while enhancing performance

    Lightweight User Interfaces for Watch Based Displays. Paper presented at

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    Ubiquitous mobile computing devices offer the opportunity to provide easy access to a rich set of information sources. Placing the display for this computing device on the user’s wrist allows for quick, easy, and pervasive access to this information. In this paper we describe a user interface model and a set of five applications we have developed, with the aim of providing a user interface that supports lightweight interactions. Our goal is to make our pervasive watch as simple to use as a common wrist-watch worn today

    A Lightweight UI Software Infrastructure for Wrist-Based Displays

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    Supporting a rich array of information sources is a key element to making highly mobile computing devices usable by the wider community. It is our belief that there will not be one specific killer application for this form of computing device, but an array of applications that the user can easily access. These applications will be context sensitive and associated with a range of activities. We have developed a custom watch platform that acts as a display for presenting this type of information to the user. In order to make the watch as small and low powered as possible, we have offloaded the processing onto an external mobile device we term a personal server, which is also carried by the user. We present our lightweight software infrastructure supporting a wrist-based display communicating with a portable personal server.

    Heterogeneous wireless network management

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    Abstract. Today’s wireless networks are highly heterogeneous, with mobile devices consisting of multiple wireless network interfaces (WNICs). Since battery lifetime is limited, power management of the interfaces has become essential. We develop an integrated approach for the management of power and performance of mobile devices in heterogeneous wireless environments. Our policy decides which WNIC to employ for a given application and optimizes its usage based on the current power and performance needs of the system. The policy dynamically switches between WNICs during program execution if data communication requirements and/or network conditions change. We have experimentally characterized Bluetooth and 802.11b wireless interfaces. Our policy has been implemented on HP’s IPAQ portable device communicating with HP’s HotSpot server [14]. The applications we tested range from MPEG video to email. The results show that our policy offers a large improvement in power savings as compared to singly using 802.11b or Bluetooth while enhancing performance.

    Toward Systematic Screening for Persistent Hepatitis E Virus Infections in Transplant Patients.

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    BACKGROUND Persistent hepatitis E virus genotype 3 (HEV G3) infections affect solid organ transplant (SOT) recipients and hematopoietic stem cell transplant (HSCT) recipients, but the burden in these cohorts in the United Kingdom is unknown. We established an audit to determine the point prevalence of HEV viremia in SOT and HSCT patients in the United Kingdom and compare different testing approaches to inform screening strategies. METHODS Between January 5, 2016, and September 21, 2016, 3044 patients undergoing therapeutic drug monitoring at a single transplant center were screened for HEV ribonucleic acid (RNA) in minipools. A total of 2822 patients who could be characterized included 2419 SOT patients, 144 HSCT patients and 259 patients with no available transplant history. HEV RNA-positive samples were characterized by serology and genomic phylogeny. HEV antigen (HEV-Ag) testing was performed on RNA-positive samples, 420 RNA-negative samples and 176 RNA-negative blood donor samples. RESULTS Nineteen of 2822 patients were viremic with G3 HEV giving a prevalence of 0.67%. The median alanine aminotransferase was significantly higher in the HEV viremic patients (P < 0.0001); however, 2 viremic patients had an alanine aminotransferase value within the normal range at the time of screening. The HEV-Ag assay identified 18/19 viremic patients and all those patients with proven viremia longer than 4 weeks. CONCLUSIONS Transplant recipients in the United Kingdom are at a low but significant risk of HEV infection. HEV-Ag detection could be an alternative to RNA detection where the goal is to identify established persistent HEV infection, particularly where expertise, facilities, or cost prohibit RNA testing
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