13,285 research outputs found
Dynamic Analysis of Executables to Detect and Characterize Malware
It is needed to ensure the integrity of systems that process sensitive
information and control many aspects of everyday life. We examine the use of
machine learning algorithms to detect malware using the system calls generated
by executables-alleviating attempts at obfuscation as the behavior is monitored
rather than the bytes of an executable. We examine several machine learning
techniques for detecting malware including random forests, deep learning
techniques, and liquid state machines. The experiments examine the effects of
concept drift on each algorithm to understand how well the algorithms
generalize to novel malware samples by testing them on data that was collected
after the training data. The results suggest that each of the examined machine
learning algorithms is a viable solution to detect malware-achieving between
90% and 95% class-averaged accuracy (CAA). In real-world scenarios, the
performance evaluation on an operational network may not match the performance
achieved in training. Namely, the CAA may be about the same, but the values for
precision and recall over the malware can change significantly. We structure
experiments to highlight these caveats and offer insights into expected
performance in operational environments. In addition, we use the induced models
to gain a better understanding about what differentiates the malware samples
from the goodware, which can further be used as a forensics tool to understand
what the malware (or goodware) was doing to provide directions for
investigation and remediation.Comment: 9 pages, 6 Tables, 4 Figure
Quantifying uncertainty in acoustic measurements of tidal flows using a ‘Virtual’ Doppler Current Profiler
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Accurate characterisation of flows at tidal sites can enable the developers of tidal stream energy projects to design and model the loads on, and the performance of, tidal energy converters. Acoustic Doppler technology is versatile in the measurement of sea conditions; however, this technology can be limited in its effectiveness at measuring the small-scale kinematic fluctuations caused by waves and turbulence. A Virtual Doppler Current Profiler (VDCP) is used to sample a simulated tidal flow to understand the limitations of this type of measurement instrument whilst recording the small timescale kinematics of waves and turbulence in tidal currents. Results demonstrate the phase dependency of velocity measurements averaged between two acoustic beams and provide a theoretical error for wave and turbulence characteristics sampled under a range of conditions. Spectral moments of the subsurface longitudinal wave orbital velocities recorded by the VDCP can be between 0.1 and 9 times those measured at a point for certain turbulent current conditions, turbulence intensity measurements may vary between 0.2 and 1.5 times the inputted value in low wave conditions and turbulence length scale calculation can also vary hugely dependent on both current and wave conditions. The continuation of this work will enable effective comparison of a linear model for tidal flow kinematics against field measurements from UK tidal site data, and subsequently validate numerical models for the testing of tidal turbines.This work was supported by the Industrial Centre for Offshore Renewable Energy (IDCORE) with funding from the Energy Technologies Institute and the Research Councils Energy Programme [grant number EP/J500847/1] and DNV GL
What Makes a Utopia Inconvenient? On the Advantages and Disadvantages of a Realist Orientation to Politics
Contemporary politics is often said to lack utopias. For prevailing understandings of the practical force of political theory, this looks like cause for celebration. As blueprints to apply to political practice, utopias invariably seem too strong or too weak. Through an immanent critique of political realism, I argue that utopian thought, and political theory generally, is better conceived as supplying an orientation to politics. Realists including Bernard Williams and Raymond Geuss explain how utopian programs like universal human rights poorly orient their adherents to politics, but the realists wrongly conclude that utopias and other ideal theories necessarily disorient us. As I show through an analysis of utopian claims made by Michel Foucault, Malcolm X, and John Rawls, utopias today can effectively disrupt entrenched forms of legitimation, foster new forms of political identity, and reveal new possibilities within existing institutions. Utopias are needed to understand the political choices we face today
Reconstruction Control of Magnetic Properties during Epitaxial Growth of Ferromagnetic Mn_3-δGa on Wurtzite GaN(0001)
Binary ferromagnetic Mn_3-δGa (1.2<3-δ≤1.5) crystalline thin films have been epitaxially grown on wurtzite GaN(0001) surfaces using rf N-plasma molecular beam epitaxy. The film structure is face-centered tetragonal with CuAu type-I (L1_0) ordering with (111) orientation. The in-plane epitaxial relationship to GaN is nearly ideal with [11̅ 0]_MnGa∥[11̅ 00]_GaN and [112̅ ]_MnGa∥[112̅ 0]_GaN. We observe magnetic anisotropy along both the in-plane and out-of-plane directions. The magnetic moments are found to depend on the Mn/(Mn+Ga) flux ratio and can be controlled by observation of the surface reconstruction during growth, which varies from 1×1 to 2×2 with increasing Mn stoichiometry
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Microfoundations of organizational paradox: The problem is how we think about the problem
Competing tensions and demands pervade our work lives. Accumulating research examines organizational and leadership approaches to leveraging these tensions. But what about individuals within firms? Although early paradox theory built upon micro-level insights from psychology and philosophy to understand the nature and management of varied competing demands, corresponding empirical studies are rare, offering scarce insights into why some individuals thrive with tensions while others struggle. In response, we contribute to the microfoundations of organizational paradox with a theoretical model and robust measures that help unpack individuals' varied approaches to tensions. Following rigorous scale development in Study 1, including samples from the US, UK, Israel, and China, we test our model in a large firm in the US using quantitative and qualitative methods. We identify resource scarcity (i.e. limited time and funding) as a source of tensions. We also demonstrate that a paradox mindset - the extent to which one is accepting of and energized by tensions - can help individuals leverage them to improve in-role job performance and innovation. Our results highlight paradox mindset as a key to unlocking the potential of everyday tensions
Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus
PMCID: PMC3744404This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication
The Na+/Ca2+, K+ exchanger NCKX4 is required for efficient cone-mediated vision
Calcium (Ca2+) plays an important role in the function and health of neurons. In vertebrate cone photoreceptors, Ca2+ controls photoresponse sensitivity, kinetics, and light adaptation. Despite the critical role of Ca2+ in supporting the function and survival of cones, the mechanism for its extrusion from cone outer segments is not well understood. Here, we show that the Na+/Ca2+, K+ exchanger NCKX4 is expressed in zebrafish, mouse, and primate cones. Functional analysis of NCKX4-deficient mouse cones revealed that this exchanger is essential for the wide operating range and high temporal resolution of cone-mediated vision. We show that NCKX4 shapes the cone photoresponse together with the cone-specific NCKX2: NCKX4 acts early to limit response amplitude, while NCKX2 acts late to further accelerate response recovery. The regulation of Ca2+ by NCKX4 in cones is a novel mechanism that supports their ability to function as daytime photoreceptors and promotes their survival
Finiteness and children with specific language impairment: an exploratory study
Children with specific language impairment (SLI) are well known for their difficulties in mastering the inflectional paradigms; in the case of learning German they also have problems with the appropriate verb position, in particular with the verb in second position. This paper explores the possibilities of applying a broader concept of finiteness to data from children with SLI in order to put their deficits, or rather their skills, into a wider perspective. The concept, as developed by Klein (1998, 2000), suggests that finiteness is tied to the assertion that a certain state of affairs is valid with regard to some topic time; that is, finiteness relates the propositional content to the topic component. Its realization involves the interaction of various grammatical devices and, possibly, lexical means like temporal adverbs. Furthermore, in the acquisition of finiteness it has been found that scope particles play a major role in both first- and second-language learning. The purpose of this paper is to analyze to what extent three German-learning children with SLI have mastered these grammatical and lexical means and to pinpoint the phase in the development of finiteness they have reached. The data to be examined are mostly narrative and taken from conversations and experiments. It will be shown that each child chooses a different developmental path to come to grips with the interaction of these devices
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