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关键词： Frequency estimation   Accuracy   Source address validation   Routing protocols   Information processing   Filtering   Time-frequency analysis   Distributed databases   Computer science   Wide area networks   Data streams   global top- K   top- K -fairness   sketch  

摘要： Finding top-K frequent items has been a hot topic in data stream processing with wide-ranging applications. However, most existing sketch algorithms focus on finding local top-K in a single data stream. In this paper, we tackle finding global top-K across multiple data streams. We find that using prior sketch algorithms directly is often unfair in global scenarios, degrading global top-K accuracy. We define top-K-fairness and show its importance for finding global top-K. To achieve this, we propose the Double-Anonymous (DA) sketch, where double-anonymity ensures fairness. We also propose two techniques, hot-filtering and early-freezing, to improve accuracy further. We theoretically prove that the DA sketch achieves top-K-fairness while maintaining high accuracy. Extensive experiments verify top-K-fairness in disjoint data streams, showing that the DA sketch's error is up to 129 times (60 times on average) smaller than the state-of-the-art. To enhance the applicability and technical depth, we also investigate how to extend the DA sketch to general distributed data stream scenarios and how to provide a fairer and more accurate global ranking for top-K items. The experimental results show that the extended version of the DA sketch can indeed compute better rankings and still has significant advantages in general data streams.

关键词： Task analysis   Optimization   Knowledge transfer   Knowledge acquisition   Evolutionary computation   Computer science   Vehicle routing   Evolutionary computation (EC)   evolutionary many-task optimization (EMaTO)   evolutionary multitask optimization (EMTO)   knowledge transfer   structure-preserved knowledge   tree-based knowledge propagation (TKP)  

摘要： As a challenging research topic in evolutionary multitask optimization (EMTO), evolutionary many-task optimization (EMaTO) aims at solving more than three tasks simultaneously. The design of the EMaTO algorithm generally needs to consider two major open issues, which are how to obtain useful knowledge from similar source tasks and how to effectively transfer knowledge to the target task. In this article, we discover that knowledge structure plays a significant role in dealing with these two issues and propose a novel knowledge structure preserving-based evolutionary algorithm (KSP-EA) to efficiently solve many-task optimization problems. KSP-EA aims to achieve two goals, which are first to obtain useful structure-preserved knowledge from similar source tasks and second to effectively transfer both direct and indirect knowledge to the target task. To achieve the first goal, we propose a local-structure-preserved knowledge acquisition strategy that projects the knowledge of similar source tasks into a unified subspace without loss of the knowledge structure, thus enhancing the quality of the obtained knowledge. To achieve the second goal, we propose a tree-based knowledge propagation strategy that constructs a knowledge propagating tree to connect all the tasks and propagates knowledge along the edges of this tree. This way, the target task can obtain both direct and indirect knowledge, improving the effectiveness of knowledge transfer. We conduct extensive experiments on CEC19 and WCCI22 many-task optimization test suites and a real-world application scenario to evaluate the performance of KSP-EA. The experimental results show that our KSP-EA generally outperforms state-of-the-art algorithms.

关键词： Computer science   Engineering   Energy engineering  

摘要： This study addresses the challenge of virtual machine (VM) placement in cloud computing to improve resource utilization and energy efficiency. We propose a mixed integer linear programming (MILP) model incorporating G-robustness theory to handle uncertainties in VM usage, optimizing both performance and energy consumption. A heuristic algorithm is developed for large-scale VM allocation. Experiments with Huawei Cloud data demonstrate significant improvements in resource utilization and energy efficiency.

关键词： Computer science   Social sciences   Psychology  

摘要： Social status, which represents the relative dominance structure in societies, forms the backdrop against which most social decisions are made. Effective social decision-making demands flexible integration of decision attribute weight (importance of an attribute) and attribute latency (when attributes start to affect decisions). However, current understanding of how attribute weight and latency are influenced by relative social status is limited. In three experiments, we dynamically manipulated subjects' relative social status before they engaged in an altruistic decision task and found that their altruistic behavior was better explained by a time-varying drift diffusion model, in which relative social status selectively modulated attribute latency but not attribute weights. Furthermore, prosocial subjects exhibited higher sensitivity to attribute latency in response to changes in relative social status compared with individualistic subjects. Our results introduce a new dimension to the computational mechanisms underlying the intricate interplay between relative social status and attribute integration.

关键词： Computer science   Condensed-matter physics   Quantum information  

摘要： Analysis pokes holes in protocol that underpins Microsoft’s claim to have created the first topological qubits.

关键词： Computer science   Machine learning  

摘要： New metric assesses how AI is getting better at completing long tasks — but some researchers are wary of long-term predictions.

关键词： Computer science   Condensed-matter physics   Quantum information  

摘要： Some attendees at a packed presentation were curious about the prospect of the first ‘topological’ qubits, but left with questions unanswered.

摘要： The use of water as a weapon in highly industrialized areas in the Russo-Ukrainian war has resulted in catastrophic economic and environmental damages. We analyze environmental effects caused by the military destruction of the Kakhovka Dam. We link field, remote sensing, and modeling data to demarcate the disaster's spatial-temporal scales and outline trends in reestablishment of damaged ecosystems. Although media attention has focused on the immediate impacts of flooding on society, politics, and the economy, our results show that toxic contamination within newly exposed sediments of the former reservoir bed poses a largely overlooked long-term threat to freshwater, estuarine, and marine ecosystems. The continued use of water as a weapon may lead to even greater risks for people and the environment.

关键词： Computer science   Quantum information   Information technology  

摘要： Quantum computers have gained the powerful abstractions that allow programmers of classical computers to design and integrate new apps and hardware, and connect devices into networks with ease.

关键词： Educational technology  

摘要： In this paper, we present an educational project aimed to introduce students to the technology behind Captive Portals infrastructures. For doing this, we developed a series of modules to emphasize each of the different aspects and features of this technology. The project is based on an open source implementation which is widely used in many computer network courses, making it well-suited and very appealing for instructors and practitioners in this field. Copyright © 2025, The Authors. All rights reserved.