87 research outputs found

    Weak Lensing Reconstruction by Counting DECaLS Galaxies

    Full text link
    Alternative to weak lensing measurements through cosmic shear, we present a weak lensing convergence κ^\hat{\kappa} map reconstructed through cosmic magnification effect in DECaLS galaxies of the DESI imaging surveys DR9. This is achieved by linearly weighing 1212 maps of galaxy number overdensity in different magnitude bins of grzgrz photometry bands. The weight is designed to eliminate the mean galaxy deterministic bias, minimize galaxy shot noise while maintaining the lensing convergence signal. We also perform corrections of imaging systematics in the galaxy number overdensity. The κ^\hat{\kappa} map has 83658365 deg2^2 sky coverage. Given the low number density of DECaLS galaxies, the κ^\hat{\kappa} map is overwhelmed by shot noise and the map quality is difficult to evaluate using the lensing auto-correlation. Alternatively, we measure its cross-correlation with the cosmic shear catalogs of DECaLS galaxies of DESI imaging surveys DR8, which has 83658365 deg2^2 overlap in sky coverage with the κ^\hat{\kappa} map. We detect a convergence-shear cross-correlation signal with S/N≃10S/N\simeq 10. The analysis also shows that the galaxy intrinsic clustering is suppressed by a factor O(102)\mathcal{O}(10^2) and the residual galaxy clustering contamination in the κ^\hat{\kappa} map is consistent with zero. Various tests with different galaxy and shear samples, and the Akaike information criterion analysis all support the lensing detection. So is the imaging systematics corrections, which enhance the lensing signal detection by ∼30%\sim 30\%. We discuss various issues for further improvement of the measurements

    A hyper-heuristic based ensemble genetic programming approach for stochastic resource constrained project scheduling problem

    Get PDF
    In project scheduling studies, to the best of our knowledge, the hyper-heuristic collaborative scheduling is first-time applied to project scheduling with random activity durations. A hyper-heuristic based ensemble genetic programming (HH-EGP) method is proposed for solving stochastic resource constrained project scheduling problem (SRCPSP) by evolving an ensemble of priority rules (PRs). The proposed approach features with (1) integrating the critical path method into the resource-based policy class to generate schedules; (2) improving the existing single hyper-heuristic project scheduling research to construct a suitable solution space for solving SRCPSP; and (3) bettering genetic evolution of each subpopulation from a decision ensemble with three different local searches in corporation with discriminant mutation and discriminant population renewal. In addition, a sequence voting mechanism is designed to deal with collaborative decision-making in the scheduling process for SRCPSP. The benchmark PSPLIB is performed to verify the advantage of the HH-EGP over heuristics, meta-heuristics and the single hyper-heuristic approaches

    Kuaipedia: a Large-scale Multi-modal Short-video Encyclopedia

    Full text link
    Online encyclopedias, such as Wikipedia, have been well-developed and researched in the last two decades. One can find any attributes or other information of a wiki item on a wiki page edited by a community of volunteers. However, the traditional text, images and tables can hardly express some aspects of an wiki item. For example, when we talk about ``Shiba Inu'', one may care more about ``How to feed it'' or ``How to train it not to protect its food''. Currently, short-video platforms have become a hallmark in the online world. Whether you're on TikTok, Instagram, Kuaishou, or YouTube Shorts, short-video apps have changed how we consume and create content today. Except for producing short videos for entertainment, we can find more and more authors sharing insightful knowledge widely across all walks of life. These short videos, which we call knowledge videos, can easily express any aspects (e.g. hair or how-to-feed) consumers want to know about an item (e.g. Shiba Inu), and they can be systematically analyzed and organized like an online encyclopedia. In this paper, we propose Kuaipedia, a large-scale multi-modal encyclopedia consisting of items, aspects, and short videos lined to them, which was extracted from billions of videos of Kuaishou (Kwai), a well-known short-video platform in China. We first collected items from multiple sources and mined user-centered aspects from millions of users' queries to build an item-aspect tree. Then we propose a new task called ``multi-modal item-aspect linking'' as an expansion of ``entity linking'' to link short videos into item-aspect pairs and build the whole short-video encyclopedia. Intrinsic evaluations show that our encyclopedia is of large scale and highly accurate. We also conduct sufficient extrinsic experiments to show how Kuaipedia can help fundamental applications such as entity typing and entity linking

    Research on priority rules for the stochastic resource constrained multi-project scheduling problem with new project arrival

    Get PDF
    The resource constrained multi-project scheduling problem (RCMPSP) is a general and classic problem, which is usually considered and solved in a deterministic environment. However, in real project management, there are always some unforeseen factors such as one or more new project arrivals that give rise to intermittent changes in the activity duration (or stochastic duration) of the current project in execution by inserting the new project. This study takes two practical factors in terms of stochastic duration of project activities and new project arrivals waiting for insertion into account of the problem space to form a stochastic resource constrained multi-project scheduling problem with new project arrivals (SRCMPSP-NPA). Based on the benchmark of the PSPLIB (Project Scheduling Problem Library), a new data set is built and 20 priority rules (PRs) are applied to solve the problem and their performances are analyzed. In addition, a heuristic hybrid method is designed for solving the problem timely by dividing the entire scheduling process into multi-state scheduling problems solved by the corresponding rules separately. This approach has been verified by experiments and its performance is better than that of a single rule in most situations

    Electroshock treatment dependent microstructural evolution and mechanical properties of near-β titanium alloy manufactured by directed energy deposition

    Get PDF
    Effects of electroshock treatment (EST) on the microstructural evolution and mechanical properties of near-β titanium alloy (Ti-55531) formed by directed energy deposition (DED) was studied in this work. With the increase in EST time, the average hardness of specimen decreased from 426 HV to 316 HV, and the fracture strain increased significantly, which was attributed to the uniform dispersion of α phase along grain boundaries and inside the β grains. After EST, the texture intensity decreased in terms of the orientation distribution function (ODF), which was ascribed to the redistribution of α phase. Moreover, more atomic vacancies and lattice distortion were formed near the α/β interfaces, which were verified by transmission electron microscopy (TEM) observation and ascribed to the migration of atoms near the interface under EST. External loadings facilitated the dislocation motion and lattice distortions near the interfaces, which resulted in the reduction in hardness and the improvement in ductility. The above results indicated that EST can quickly alter the microstructure and mechanical properties of DED titanium alloys as a simple and energy-saving method

    Bi-level dynamic scheduling architecture based on service unit digital twin agents

    Get PDF
    Pure reactive scheduling is one of the core technologies to solve the complex dynamic disturbance factors in real-time. The emergence of CPS, digital twin, cloud computing, big data and other new technologies based on the industrial Internet enables information acquisition and pure reactive scheduling more practical to some extent. However, how to build a new architecture to solve the problems which traditional dynamic scheduling methods cannot solve becomes a new research challenge. Therefore, this paper designs a new bi-level distributed dynamic workshop scheduling architecture, which is based on the workshop digital twin scheduling agent and multiple service unit digital twin scheduling agents. Within this architecture, scheduling a physical workshop is decomposed to the whole workshop scheduling in the first level and its service unit scheduling in the second level. On the first level, the whole workshop scheduling is executed by its virtual workshop coordination (scheduling) agent embedded with the workshop digital twin consisting of multi-service unit digital twins. On the second level, each service unit scheduling coordinated by the first level scheduling is executed in a distributed way by the corresponding service unit scheduling agent associated with its service unit digital twin. The benefits of the new architecture include (1) if a dynamic scheduling only requires a single service unit scheduling, it will then be performed in the corresponding service unit scheduling without involving other service units, which will make the scheduling locally, simply and robustly. (2) when a dynamic scheduling requires changes in multiple service units in a coordinated way, the first level scheduling will be executed and then coordinate the second level service unit scheduling accordingly. This divide-and-then-conquer strategy will make the scheduling easier and practical. The proposed architecture has been tested to illustrate its feasibility and practicality

    Vaccines for African swine fever: an update

    Get PDF
    African swine fever (ASF) is a fatal infectious disease of swine caused by the African swine fever virus (ASFV). Currently, the disease is listed as a legally notifiable disease that must be reported to the World Organization for Animal Health (WOAH). The economic losses to the global pig industry have been insurmountable since the outbreak of ASF. Control and eradication of ASF are very critical during the current pandemic. Vaccination is the optimal strategy to prevent and control the ASF epidemic, but since inactivated ASFV vaccines have poor immune protection and there aren’t enough cell lines for efficient in vitro ASFV replication, an ASF vaccine with high immunoprotective potential still remains to be explored. Knowledge of the course of disease evolution, the way of virus transmission, and the breakthrough point of vaccine design will facilitate the development of an ASF vaccine. In this review, the paper aims to highlight the recent advances and breakthroughs in the epidemic and transmission of ASF, virus mutation, and the development of vaccines in recent years, focusing on future directions and trends

    DESI Legacy Imaging Surveys Data Release 9: Cosmological Constraints from Galaxy Clustering and Weak Lensing using the Minimal Bias Model

    Full text link
    We present a tentative constraint on cosmological parameters Ωm\Omega_m and σ8\sigma_8 from a joint analysis of galaxy clustering and galaxy-galaxy lensing from DESI Legacy Imaging Surveys Data Release 9 (DR9), covering approximately 10000 square degrees and spanning the redshift range of 0.1 to 0.9. To study the dependence of cosmological parameters on lens redshift, we divide lens galaxies into seven approximately volume-limited samples, each with an equal width in photometric redshift. To retrieve the intrinsic projected correlation function wp(rp)w_{\rm p}(r_{\rm p}) from the lens samples, we employ a novel method to account for redshift uncertainties. Additionally, we measured the galaxy-galaxy lensing signal ΔΣ(rp)\Delta\Sigma(r_{\rm p}) for each lens sample, using source galaxies selected from the shear catalog by applying our \texttt{Fourier\_Quad} pipeline to DR9 images. We model these observables within the flat Λ\LambdaCDM framework, employing the minimal bias model. To ensure the reliability of the minimal bias model, we apply conservative scale cuts: rp>8r_{\rm p} > 8 and 12 h−1Mpc12 ~h^{-1}{\rm Mpc}, for wp(rp)w_{\rm p}(r_{\rm p}) and ΔΣ(rp)\Delta\Sigma(r_{\rm p}), respectively. Our findings suggest a mild tendency that S8≡σ8Ωm/0.3S_8 \equiv \sigma_8 \sqrt{\Omega_m/0.3} increases with lens redshift, although this trend is only marginally significant. When we combine low redshift samples, the value of S8S_8 is determined to be 0.84±0.020.84 \pm 0.02, consistent with the Planck results but significantly higher than the 3×\times 2pt analysis by 2-5σ\sigma. Despite the fact that further refinements in measurements and modeling could improve the accuracy of our results, the consistency with standard values demonstrates the potential of our method for more precise and accurate cosmology in the future.Comment: slightly different with the published versio
    • …
    corecore