71 research outputs found

    A Parallel Genetic Algorithm For Tuning Neural Networks

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    One challenge in using artificial neural networks is how to determine appropriate parameters for network structure and learning. Often parameters such as learning rate or number of hidden units are set arbitrarily or with a general intuition as to what would be most effective. The goal of this project is to use a genetic algorithm to tune a population of neural networks to determine the best structure and parameters. This paper considers a genetic algorithm to tune the number of hidden units, learning rate, momentum, and number of examples viewed per weight update. Experiments and results are discussed for two domains with distinct properties, demonstrating the importance of careful tuning of network parameters and structure for best performance

    Strengthening student engagement: evaluating the role of the digital skills agenda in higher education.

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    Digital technology can contribute to all three areas of the TEF: teaching quality; learning environment; and student outcomes (Davies S, Mullan and Feldman 2017). Digital skills are helpful in designing enhanced and effective learning activities (Copley 2007), as multimedia promotes interests and engagement. It provides flexibility for students, in terms of where and when they can undertake their learning activity. It therefore improves student experience and outcomes (Davies S, Mullan and Feldman 2017). Its use enhances feedback: task feedback through online submissions; process feedback through audio and video feedbacks; and self-regulation feedback through computer simulation, as well as anonymous instructor and peer feedback (Hattie 2012). It can help in developing effective learning environments, from basic websites to augmented reality simulations (Dreyer and Nel, 2003). Therefore, in the present environment, digital agenda should be an integral part of continuing professional development (CPD)

    Practical Graphs for Optimal Side-Channel Resistant Memory-Hard Functions

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    A memory-hard function (MHF) fnf_n with parameter nn can be computed in sequential time and space nn. Simultaneously, a high amortized parallel area-time complexity (aAT) is incurred per evaluation. In practice, MHFs are used to limit the rate at which an adversary (using a custom computational device) can evaluate a security sensitive function that still occasionally needs to be evaluated by honest users (using an off-the-shelf general purpose device). The most prevalent examples of such sensitive functions are Key Derivation Functions (KDFs) and password hashing algorithms where rate limits help mitigate off-line dictionary attacks. As the honest users\u27 inputs to these functions are often (low-entropy) passwords special attention is given to a class of side-channel resistant MHFs called iMHFs. Essentially all iMHFs can be viewed as some mode of operation (making nn calls to some round function) given by a directed acyclic graph (DAG) with very low indegree. Recently, a combinatorial property of a DAG has been identified (called ``depth-robustness\u27\u27) which results in good provable security for an iMHF based on that DAG. Depth-robust DAGs have also proven useful in other cryptographic applications. Unfortunately, up till now, all known very depth-robust DAGs are impractically complicated and little is known about their exact (i.e. non-asymptotic) depth-robustness both in theory and in practice. In this work we build and analyze (both formally and empirically) several exceedingly simple and efficient to navigate practical DAGs for use in iMHFs and other applications. For each DAG we: - Prove that their depth-robustness is asymptotically maximal. - Prove bounds of at least 33 orders of magnitude better on their exact depth-robustness compared to known bounds for other practical iMHF. - Implement and empirically evaluate their depth-robustness and aAT against a variety of state-of-the art (and several new) depth-reduction and low aAT attacks. We find that, against all attacks, the new DAGs perform significantly better in practice than Argon2i, the most widely deployed iMHF in practice. Along the way we also improve the best known empirical attacks on the aAT of Argon2i by implementing and testing several heuristic versions of a (hitherto purely theoretical) depth-reduction attack. Finally, we demonstrate practicality of our constructions by modifying the Argon2i code base to use one of the new high aAT DAGs. Experimental benchmarks on a standard off-the-shelf CPU show that the new modifications do not adversely affect the impressive throughput of Argon2i (despite seemingly enjoying significantly higher aAT)

    Visual Information Management for Network Configuration

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    Current network management systems rely heavily on forms in their user interfaces. the interfaces reflect the intricacies of the network hardware components but provide little support for guiding users through tasks. There is a scarcity of useful graphical visualizations and decision-support tools. We applied a task-oriented approach to design and implemented the user interface for a prototype network configuration management system. Our user interface provides mulitple overviews of the network (with potentially thousands of nodes) and the relevant configuration tasks (queries and updates). We propose a unified interface for exploration, querying, data entry and verification. Compact color-coded treemaps with dynamic queries allowing user-controlled filtering and animation of the data display proved well-suited for representing the multiple containment hierarchies in networks. Our Tree-browser applied the conventional node-link visualization of trees to show hardware containment hierarchies. Improvements to conventional scrollbar- browsers included tightly coupled overviews and detailed views. This visual interface, implemented with Galaxy and the University of Maryland Widget Library(TM), has received enthusiastic feedback from the network management community. This application-specific paper has design paradigms that should be useful to designers of varied systems. (Also cross-referenced as: CAR-TR-716) (Also cross-referenced as: ISR-TR-94-45

    Protocol to develop a core outcome set in incisional hernia surgery : the HarMoNY Project

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    Incisional hernia has an incidence of up to 20% following laparotomy and is associated with significant morbidity and impairment of quality of life. A variety of surgical strategies including techniques and mesh types are available to manage patients with incisional hernia. Previous works have reported significant heterogeneity in outcome reporting for abdominal wall herniae, including ventral and inguinal hernia. This is coupled with under-reporting of important clinical and patient-reported outcomes. The lack of standardisation in outcome reporting contributes to reporting bias, hinders evidence synthesis and adequate data comparison between studies. This project aims to develop a core outcome set (COS) of clinically important, patient-oriented outcomes to be used to guide reporting of future research in incisional hernia. This project has been designed as an international, multicentre, mixed-methods project. Phase I will be a systematic review of current literature to examine the current clinical and patient-reported outcomes for incisional hernia and abdominal wall reconstruction. Phase II will identify the outcomes of importance to all key stakeholders through in depth qualitative interviews. Phase III will achieve consensus on outcomes of most importance and for inclusion into a COS through a Delphi process. Phase IV will achieve consensus on the outcomes that should be included in a final COS. The adoption of this COS into clinical and academic practice will be endorsed by the American, British and European Hernia Societies. Its utilisation in future clinical research will enable appropriate data synthesis and comparison and will enable better clinical interpretation and application of the current evidence base. This study has been registered with the Core Outcome Measures in Effectiveness Trials initiative. CRD42018090084

    Next Generation Network Management Technology

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    Today's telecommunications networks are becoming increasingly large, complex, mission critical and heterogeneous in several dimensions. For example, the underlying physical transmission facilities of a given network may be ﲭixed media (copper, fiber- optic, radio, and satellite); the sub networks may be acquired from different vendors due to economic, performance, or general availability reasons; the information being transmitted over the network may be ﲭultimedia (video, data, voice, and images) and, finally, varying performance criteria may be imposed e.g. data transfer may require high throughput while the others, whose concern is voice communications, may require low call blocking probability. For these reasons, future telecommunications networks are expected to be highly complex in their services and operations. Due to this growing complexity and the disparity among management systems for individual sub networks, efficient network management systems have become critical to the current and future success of telecommunications companies. This paper addresses a research and development effort which focuses on prototyping configuration management, since that is the central process of network management and all other network management functions must be built upon it. Our prototype incorporates ergonomically designed graphical user interfaces tailored to the network configuration management subsystem and to the proposed advanced object-oriented database structure. The resulting design concept follows open standards such as Open Systems Interconnection (OSI) and incorporates object oriented programming methodology to associate data with functions, permit customization, and provide an open architecture environment. A revised version of this technical report has been published in The 12th Symposium on Space Nuclear Power and Propulsion/Commercialization, pp. 75-82, Albuquerque, NM, January 8-12, 1995.</ul

    Genome-enabled insights into the biology of thrips as crop pests

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    Background The western flower thrips, Frankliniella occidentalis (Pergande), is a globally invasive pest and plant virus vector on a wide array of food, fiber, and ornamental crops. The underlying genetic mechanisms of the processes governing thrips pest and vector biology, feeding behaviors, ecology, and insecticide resistance are largely unknown. To address this gap, we present the F. occidentalis draft genome assembly and official gene set. Results We report on the first genome sequence for any member of the insect order Thysanoptera. Benchmarking Universal Single-Copy Ortholog (BUSCO) assessments of the genome assembly (size = 415.8 Mb, scaffold N50 = 948.9 kb) revealed a relatively complete and well-annotated assembly in comparison to other insect genomes. The genome is unusually GC-rich (50%) compared to other insect genomes to date. The official gene set (OGS v1.0) contains 16,859 genes, of which ~ 10% were manually verified and corrected by our consortium. We focused on manual annotation, phylogenetic, and expression evidence analyses for gene sets centered on primary themes in the life histories and activities of plant-colonizing insects. Highlights include the following: (1) divergent clades and large expansions in genes associated with environmental sensing (chemosensory receptors) and detoxification (CYP4, CYP6, and CCE enzymes) of substances encountered in agricultural environments; (2) a comprehensive set of salivary gland genes supported by enriched expression; (3) apparent absence of members of the IMD innate immune defense pathway; and (4) developmental- and sex-specific expression analyses of genes associated with progression from larvae to adulthood through neometaboly, a distinct form of maturation differing from either incomplete or complete metamorphosis in the Insecta. Conclusions Analysis of the F. occidentalis genome offers insights into the polyphagous behavior of this insect pest that finds, colonizes, and survives on a widely diverse array of plants. The genomic resources presented here enable a more complete analysis of insect evolution and biology, providing a missing taxon for contemporary insect genomics-based analyses. Our study also offers a genomic benchmark for molecular and evolutionary investigations of other Thysanoptera species
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