40,112 research outputs found

    Computer aided manual tracking

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    A scheme was developed to assist the human operator by augmenting an optic sight manual tracking loop with target rate estimates from a computer control algorithm which can either be a Kalman Filter or an alpha, beta, gamma filter. The idea is for the computer to provide rate tracking while the human operator is responsible for nullifying the tracking error. A simple schematic is shown to illustrate the implementation of this concept. A hybrid real-time man-in-loop simulation was used to compare the tracking performance of the same flight trajectory with or without this form of computer-aided track. Preliminary results show the advantage of computer-aided track against high speed aircraft at close range. However, good tracking before target state estimator maturity becomes more critical for aided track than without. Results are presented for a constant velocity flight trajectory

    The development of absorptive capacity-based innovation in a construction SME

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    Traditionally, construction has been a transaction-oriented industry. However, it is changing from the design-bid-build process into a business based on innovation capability and performance management, in which contracts are awarded on the basis of factors such as knowledge, intellectual capital and skills. This change presents a challenge to construction-sector SMEs with scarce resources, which must find ways to innovate based on those attributes to ensure their future competitiveness. This paper explores how dynamic capability, using an absorptive capacity framework in response to these challenges, has been developed in a construction-based SME. The paper also contributes to the literature on absorptive capacity and innovation by showing how the construct can be operationalized within an organization. The company studied formed a Knowledge Transfer Partnership using action research over a two-year period with a local university. The aim was to increase its absorptive capacity and hence its ability to meet the changing market challenges. The findings show that absorptive capacity can be operationalized into a change management approach for improving capability-based competitiveness. Moreover, it is important for absorptive capacity constructs and language to be contextualized within a given organizational setting (as in the case of the construction-based SME in the present study)

    Quantum walks: the first detected transition time

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    We consider the quantum first detection problem for a particle evolving on a graph under repeated projective measurements with fixed rate 1/τ1/\tau. A general formula for the mean first detected transition time is obtained for a quantum walk in a finite-dimensional Hilbert space where the initial state âˆŁÏˆin⟩|\psi_{\rm in}\rangle of the walker is orthogonal to the detected state âˆŁÏˆd⟩|\psi_{\rm d}\rangle. We focus on diverging mean transition times, where the total detection probability exhibits a discontinuous drop of its value, by mapping the problem onto a theory of fields of classical charges located on the unit disk. Close to the critical parameter of the model, which exhibits a blow-up of the mean transition time, we get simple expressions for the mean transition time. Using previous results on the fluctuations of the return time, corresponding to âˆŁÏˆin⟩=âˆŁÏˆd⟩|\psi_{\rm in}\rangle = |\psi_{\rm d}\rangle, we find close to these critical parameters that the mean transition time is proportional to the fluctuations of the return time, an expression reminiscent of the Einstein relation

    RsyGAN: Generative Adversarial Network for Recommender Systems

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    © 2019 IEEE. Many recommender systems rely on the information of user-item interactions to generate recommendations. In real applications, the interaction matrix is usually very sparse, as a result, the model cannot be optimised stably with different initial parameters and the recommendation performance is unsatisfactory. Many works attempted to solve this problem, however, the parameters in their models may not be trained effectively due to the sparse nature of the dataset which results in a lower quality local optimum. In this paper, we propose a generative network for making user recommendations and a discriminative network to guide the training process. An adversarial training strategy is also applied to train the model. Under the guidance of a discriminative network, the generative network converges to an optimal solution and achieves better recommendation performance on a sparse dataset. We also show that the proposed method significantly improves the precision of the recommendation performance on several datasets

    DNA Spools under Tension

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    DNA-spools, structures in which DNA is wrapped and helically coiled onto itself or onto a protein core are ubiquitous in nature. We develop a general theory describing the non-equilibrium behavior of DNA-spools under linear tension. Two puzzling and seemingly unrelated recent experimental findings, the sudden quantized unwrapping of nucleosomes and that of DNA toroidal condensates under tension are theoretically explained and shown to be of the same origin. The study provides new insights into nucleosome and chromatin fiber stability and dynamics

    Correlation between 3:2 QPO pairs and Jets in Black Hole X-ray Binaries

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    We argue, following our earlier works (the "CEBZMC model"), that the phenomenon of twin peak high frequency quasi-periodic oscillations (QPOs) observed in black hole X-ray binaries is caused by magnetic coupling (MC) between accretion disk and black hole (BH). Due to MC, two bright spots occur at two separate radial locations r_{in} and r_{out} at the disk surface, energized by a kind of the Blandford-Znajek mechanism (BZ). We assume, following the Kluzniak-Abramowicz QPO resonance model, that Keplerian frequencies at these two locations are in the 3:2 ratio. With this assumption, we estimate the BH spins in several sources, including GRO J1655-40, GRS 1915+105, XTE J1550-564, H1743-322 and Sgr A*. We give an interpretation of the "jet line" in the hardness-intensity plane discussing the parameter space consisting of the BH spin and the power-law index for the variation of the large-scale magnetic field in the disk. Furthermore, we propose a new scenario for the spectral state transitions in BH X-ray binaries based on fluctuation in densities of accreting plasma from a companion star.Comment: 17 pages, 6 figures, accepted by AP
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