2,506 research outputs found

    Software architecture for a distributed real-time system in Ada, with application to telerobotics

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    The architecture structure and software design methodology presented is described in the context of telerobotic application in Ada, specifically the Engineering Test Bed (ETB), which was developed to support the Flight Telerobotic Servicer (FTS) Program at GSFC. However, the nature of the architecture is such that it has applications to any multiprocessor distributed real-time system. The ETB architecture, which is a derivation of the NASA/NBS Standard Reference Model (NASREM), defines a hierarchy for representing a telerobot system. Within this hierarchy, a module is a logical entity consisting of the software associated with a set of related hardware components in the robot system. A module is comprised of submodules, which are cyclically executing processes that each perform a specific set of functions. The submodules in a module can run on separate processors. The submodules in the system communicate via command/status (C/S) interface channels, which are used to send commands down and relay status back up the system hierarchy. Submodules also communicate via setpoint data links, which are used to transfer control data from one submodule to another. A submodule invokes submodule algorithms (SMA's) to perform algorithmic operations. Data that describe or models a physical component of the system are stored as objects in the World Model (WM). The WM is a system-wide distributed database that is accessible to submodules in all modules of the system for creating, reading, and writing objects

    New Farmer Jump Start Project

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    Southwest Iowa development groups looked at several ways to entice new farmers to commit to local food production

    Extreme Ultraviolet Application of Carbon Nanotube Structures

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    Windows for extreme ultraviolet (EUV) sources are challenging because of the lack of transparent materials in these wavelengths. Thus, differential pumping apertures and slits are standard. Our group has developed a carbon nanotube (CNT) window consisting of a dense array of square holes. The open area allows a large range of wavelengths to be transmitted, and the high density of holes restricts gas flow, allowing a large pressure difference with differential pumping. The versatility of CNTs allows us to select the peak transmission and pressure ratio (low/high). We have observed pressure ratios of 0.000924, 0.000667, 0.000494, and 0.00118 for air at 298 K with (width-heigth in microns) 50-301, 50-654, 50-1045, and 200-675, respectively for (high) pressures up to 1 torr

    Musicco : A Social Media Platform for Musicians

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    Entertainment industry is without a doubt, composed of a big part of the economy of a nation. Within our modern world where media such as movies, games, and music is considered dominant in our everyday lives, people often find ways to express themselves or even to get attention from others by using technologies. As of today, social media like Facebook and Twitter is almost within everybody’s reach. Due to the ease of accessibility as to the existence of mobile smartphones. To some, it may serve as chance for them to generate income. The huge amount of users of these mobile applications serves as a motivation for a whole lot of people in pursuing the latter idea. Not only that, it may serve as tool to promote oneself qualities and abilities, an assist to gain recognition and fame. Though, a generalized platform would be harder to manage as it will engender low focus onto the original targeted audience or costumers. Thus, a proposed system was designed to be a specific platform, particularly into music, to challenge the outcome that may come

    Converting systematic reviews to Cochrane format: a cross-sectional survey of Australian authors of systematic reviews

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    BACKGROUND: Despite the growing reputation and subject coverage of the Cochrane Database of Systematic Reviews, many systematic reviews continue to be published solely in paper-based health care journals. This study was designed to determine why authors choose to publish their systematic reviews outside of the Cochrane Collaboration and if they might be interested in converting their reviews to Cochrane format for publication in the Cochrane Database of Systematic Reviews. METHODS: Cross-sectional survey of Australian primary authors of systematic reviews not published on the Cochrane Database of Systematic Reviews identified from the Database of Abstracts of Reviews of Effectiveness. RESULTS: We identified 88 systematic reviews from the Database of Abstracts of Reviews of Effectiveness with an Australian as the primary author. We surveyed 52 authors for whom valid contact information was available. The response rate was 88 per cent (46/52). Ten authors replied without completing the survey, leaving 36 valid surveys for analysis. The most frequently cited reasons for not undertaking a Cochrane review were: lack of time (78%), the need to undergo specific Cochrane training (46%), unwillingness to update reviews (36%), difficulties with the Cochrane process (26%) and the review topic already registered with the Cochrane Collaboration (21%). (Percentages based on completed responses to individual questions.) Nearly half the respondents would consider converting their review to Cochrane format. Dedicated time emerged as the most important factor in facilitating the potential conversion process. Other factors included navigating the Cochrane system, assistance with updating and financial support. Eighty-six per cent were willing to have their review converted to Cochrane format by another author. CONCLUSION: Time required to complete a Cochrane review and the need for specific training are the primary reasons why some authors publish systematic reviews outside of the Cochrane Collaboration. Encouragingly, almost half of the authors would consider converting their review to Cochrane format. Based on the current number of reviews in the Database of Abstracts of Reviews of Effectiveness, this could result in more than 700 additional Cochrane reviews. Ways of supporting these authors and how to provide dedicated time to convert systematic reviews needs further consideration

    Effects of pH on redox proxies in a Jurassic rift lake : implications for interpreting environmental records in deep time

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    This work was supported at the University of California, Riverside by the NSF-EAR FESD Program and the NASA Astrobiology Institute under Cooperative Agreement No. NNA15BB03A issued through the Science Mission Directorate. We thank Roger Buick (UW) for financial support of the carbon and nitrogen isotope work. EES acknowledges support from a NASA postdoctoral fellowship, as well as valuable discussions about the Newark basin with Charlotte B. Schreiber. GDL thanks the Agouron Institute for providing funding for the Waters Autospec GC-MS instrument at UCR.It is widely agreed that the Earth’s atmosphere and oceans have undergone major redox changes over the last 2.5 billion years. However, the magnitude of these shifts remains a point of debate because it is difficult to reconstruct concentrations of dissolved O2 from indirect proxies in sedimentary archives. In this study, we show that an additional complicating factor that is rarely considered may be the pH of the water column. We analyzed rock samples from the early Jurassic Towaco Formation in the Newark basin (eastern USA), comprising deposits of a rift lake that became temporarily redox stratified. New biomarker evidence points to increasingly saline aquatic conditions during the second half of the lake’s history, with a salinity stratification that induced redox stratification, including evidence for water column anoxia, and that state may also explain the disappearance of macrofauna at this time. Distinctive lipid biomarker assemblages and stable nitrogen isotope data support previous mineralogical indications that the lake was alkaline (pH ≥ 9) during its saline episode. Despite the biomarker and macrofaunal evidence for anoxia, ratios of Fe/Al and FeHR/FeT show only small to no enrichments in the anoxic horizon compared to oxic facies in the same section – counter to what is commonly observed in anoxic marine settings. Molybdenum, As, V, U and to some degree Cd show enrichments in the anoxic interval, whereas Co, Ni, Cu, Zn and Cr do not. These patterns are most parsimoniously explained by differential pH effects on the solubility of these elements. Extrapolating from these observations in lacustrine strata, we speculate that a secular increase in seawater pH over Earth’s history as recently proposed may have helped modulate the magnitude of trace metal enrichments in marine shales, although other factors such as atmospheric and oceanic redox likely dominated the observed enrichment patterns. Further, a decrease in the solubility of ferrous iron, a major O2 sink, with increasing pH may have contributed to ocean oxygenation. In summary, our results highlight the potential importance of pH in influencing global biogeochemical cycles for multiple elements and for the interpretation of ancient nitrogen isotope signatures.PostprintPeer reviewe

    A Novel Authentication and Key Agreement Scheme for Countering MITM and Impersonation Attack in Medical Facilities

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    Authentication is used to enfold the privacy of the patient to implement security onto the communication between patients and service providers. Several types of research have proposed support for anonymity for contextual privacy in medical systems that are still vulnerable to impersonation attack and Man-in-the-middle attack. By using powerful technology that is used in medical facilities, it can help in building an advanced system. However, the same powerful tools can also be used by the attackers to gain personal profits and to cause chaos. The proposed countermeasure that is to be taken to prevent this kind of attacks is by implementing mutual authentication between users, their devices/mobile devices, and the system’s cloud server, and also a key agreement scheme together with the help of Elliptic Curve Cryptography (ECC). A novel authentication scheme which consists of two phases, a signature generation, and authentication process. The ECC implementation is to ensure that the keys are thoroughly secured and is not copy- able, together with a Key generation scheme that shields the system against impersonation attacks. The usage of Elliptic Curve Digital Signature Algorithm (ECDSA), in a signature generation, on the other hand, provides users more secure way to hide the user private key and bring additional security layer before proceeding to authentication phase due to the existence of extra elements of domain parameters. Authentication is still considered as a crucial component in maintaining the security of any critical facilities that require the CIA tried and non- repudiation as a need to maintain their data. It does not only apply to medical centers, but any organizations that possess valuable data that is needed to be protected also requires strong authentication protocols. Thus, the trend for the need of novel authentication protocols will keep on rising as technology gets fancier and fancier

    Preliminary Evaluation of Convolutional Neural Network Acoustic Model for Iban Language Using NVIDIA NeMo

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    For the past few years, artificial neural networks (ANNs) have been one of the most common solutions relied upon while developing automated speech recognition (ASR) acoustic models. There are several variants of ANNs, such as deep neural networks (DNNs), recurrent neural networks (RNNs), and convolutional neural networks (CNNs). A CNN model is widely used as a method for improving image processing performance. In recent years, CNNs have also been utilized in ASR techniques, and this paper investigates the preliminary result of an end-to-end CNN-based ASR using NVIDIA NeMo on the Iban corpus, an under-resourced language. Studies have shown that CNNs have also managed to produce excellent word error (WER) rates for the acoustic model on ASR for speech data. Conversely, results and studies concerned with under-resourced languages remain unsatisfactory. Hence, by using NVIDIA NeMo, a new ASR engine developed by NVIDIA, the viability and the potential of this alternative approach are evaluated in this paper. Two experiments were conducted: the number of resources used in the works of our ASR’s training was manipulated, as was the internal parameter of the engine used, namely the epochs. The results of those experiments are then analyzed and compared with the results shown in existing papers
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