74 research outputs found
A novel hybrid firefly algorithm for global optimization
Global optimization is challenging to solve due to its nonlinearity and multimodality. Traditional algorithms such as the gradient-based methods often struggle to deal with such problems and one of the current trends is to use metaheuristic algorithms. In this paper, a novel hybrid population-based global optimization algorithm, called hybrid firefly algorithm (HFA), is proposed by combining the advantages of both the firefly algorithm (FA) and differential evolution (DE). FA and DE are executed in parallel to promote information sharing among the population and thus enhance searching efficiency. In order to evaluate the performance and efficiency of the proposed algorithm, a diverse set of selected benchmark functions are employed and these functions fall into two groups: unimodal and multimodal. The experimental results show better performance of the proposed algorithm compared to the original version of the firefly algorithm (FA), differential evolution (DE) and particle swarm optimization (PSO) in the sense of avoiding local minima and increasing the convergence rate
Collaborative Honeypot Defense in UAV Networks: A Learning-Based Game Approach
The proliferation of unmanned aerial vehicles (UAVs) opens up new
opportunities for on-demand service provisioning anywhere and anytime, but also
exposes UAVs to a variety of cyber threats. Low/medium interaction honeypots
offer a promising lightweight defense for actively protecting mobile Internet
of things, particularly UAV networks. While previous research has primarily
focused on honeypot system design and attack pattern recognition, the incentive
issue for motivating UAV's participation (e.g., sharing trapped attack data in
honeypots) to collaboratively resist distributed and sophisticated attacks
remains unexplored. This paper proposes a novel game-theoretical collaborative
defense approach to address optimal, fair, and feasible incentive design, in
the presence of network dynamics and UAVs' multi-dimensional private
information (e.g., valid defense data (VDD) volume, communication delay, and
UAV cost). Specifically, we first develop a honeypot game between UAVs and the
network operator under both partial and complete information asymmetry
scenarios. The optimal VDD-reward contract design problem with partial
information asymmetry is then solved using a contract-theoretic approach that
ensures budget feasibility, truthfulness, fairness, and computational
efficiency. In addition, under complete information asymmetry, we devise a
distributed reinforcement learning algorithm to dynamically design optimal
contracts for distinct types of UAVs in the time-varying UAV network. Extensive
simulations demonstrate that the proposed scheme can motivate UAV's cooperation
in VDD sharing and improve defensive effectiveness, compared with conventional
schemes.Comment: Accepted Aug. 28, 2023 by IEEE Transactions on Information Forensics
& Security. arXiv admin note: text overlap with arXiv:2209.1381
A Practical Quality Control Method for Saponins Without UV Absorption by UPLC-QDA
Saponins are a class of important active ingredients. Analysis of saponin-containing herbal medicines is a major challenge for the quality control of medicinal herbs in companies. Taking the medicine Astragali radix (AR) as an example, it has been shown that the existing evaporative light scattering detection (ELSD) methods of astragaloside IV (AG IV) has the disadvantages of time-consuming sample preparation and low sensitivity. The universality of ELSD results in an inapplicable fingerprint with huge signals from primary compounds and smaller signals from saponins. The purpose of this study was to provide a practical and comprehensive method for the quality control of the astragalosides in AR. A simple sample preparation method with sonication extraction and ammonia hydrolyzation was established, which shortens the preparation time from around 2 days to less than 2 h. A UPLC-QDA method with the SIM mode was established for the quantification of AG IV in AR. Methanol extract was subjected to UPLC-QDA for fingerprinting analysis, and the common peaks were assigned simultaneously with the QDA. The results showed that with the newly established method, the preparation time for a set of samples was less than 90 min. The fingerprints can simultaneously detect both saponins and flavonoids in AR. This simple, rapid, and comprehensive UPLC-QDA method is suitable for quality assessment of RA and its products in companies, and also provides references for the quality control of other saponin ingredients without UV absorption
Ghost in the Minecraft: Generally Capable Agents for Open-World Enviroments via Large Language Models with Text-based Knowledge and Memory
The captivating realm of Minecraft has attracted substantial research
interest in recent years, serving as a rich platform for developing intelligent
agents capable of functioning in open-world environments. However, the current
research landscape predominantly focuses on specific objectives, such as the
popular "ObtainDiamond" task, and has not yet shown effective generalization to
a broader spectrum of tasks. Furthermore, the current leading success rate for
the "ObtainDiamond" task stands at around 20%, highlighting the limitations of
Reinforcement Learning (RL) based controllers used in existing methods. To
tackle these challenges, we introduce Ghost in the Minecraft (GITM), a novel
framework integrates Large Language Models (LLMs) with text-based knowledge and
memory, aiming to create Generally Capable Agents (GCAs) in Minecraft. These
agents, equipped with the logic and common sense capabilities of LLMs, can
skillfully navigate complex, sparse-reward environments with text-based
interactions. We develop a set of structured actions and leverage LLMs to
generate action plans for the agents to execute. The resulting LLM-based agent
markedly surpasses previous methods, achieving a remarkable improvement of
+47.5% in success rate on the "ObtainDiamond" task, demonstrating superior
robustness compared to traditional RL-based controllers. Notably, our agent is
the first to procure all items in the Minecraft Overworld technology tree,
demonstrating its extensive capabilities. GITM does not need any GPU for
training, but a single CPU node with 32 CPU cores is enough. This research
shows the potential of LLMs in developing capable agents for handling
long-horizon, complex tasks and adapting to uncertainties in open-world
environments. See the project website at https://github.com/OpenGVLab/GITM
Efficient Deformable ConvNets: Rethinking Dynamic and Sparse Operator for Vision Applications
We introduce Deformable Convolution v4 (DCNv4), a highly efficient and
effective operator designed for a broad spectrum of vision applications. DCNv4
addresses the limitations of its predecessor, DCNv3, with two key enhancements:
1. removing softmax normalization in spatial aggregation to enhance its dynamic
property and expressive power and 2. optimizing memory access to minimize
redundant operations for speedup. These improvements result in a significantly
faster convergence compared to DCNv3 and a substantial increase in processing
speed, with DCNv4 achieving more than three times the forward speed. DCNv4
demonstrates exceptional performance across various tasks, including image
classification, instance and semantic segmentation, and notably, image
generation. When integrated into generative models like U-Net in the latent
diffusion model, DCNv4 outperforms its baseline, underscoring its possibility
to enhance generative models. In practical applications, replacing DCNv3 with
DCNv4 in the InternImage model to create FlashInternImage results in up to 80%
speed increase and further performance improvement without further
modifications. The advancements in speed and efficiency of DCNv4, combined with
its robust performance across diverse vision tasks, show its potential as a
foundational building block for future vision models.Comment: Tech report; Code: https://github.com/OpenGVLab/DCNv
Bubble Trajectory Tracking Based on ORB Algorithm
The system of gas-liquid two-phase bubbly flows is widely found in many industrial fields, such as nuclear energy, chemical, petroleum, and refrigeration. Bubbly two-phase flows measuring including detection and tracking affects the specific engineering problem solving to a great extent. The particle tracking velocity (PTV) algorithm is generally used for the tracking of the particles in the flow field. However, it does not take the shape change of particles into account in the process of flow. In this paper, a kind of bubble feature matching method based on ORB algorithm is proposed, and the edge detection method of findContours in OpenCV is used to extract the bubble contour in the image. The proposed algorithm implements the trajectory tracking of the bubbles with shape change when moving up in liquid. The feasibility of bubble trajectory tracking is shown by displaying of different bubble tracks in the plan, 3D plots and contour changing plots
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