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Towards Characterizing the Download Cost of Cache-Aided Private Updating. 缓存辅助私有更新的下载成本表征

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-08-04 DOI: 10.3390/e27080828

Bryttany Stark, Ahmed Arafa, Karim Banawan

{"title":"Towards Characterizing the Download Cost of Cache-Aided Private Updating.","authors":"Bryttany Stark, Ahmed Arafa, Karim Banawan","doi":"10.3390/e27080828","DOIUrl":"https://doi.org/10.3390/e27080828","url":null,"abstract":"We consider the problem of privately updating a message out of K messages from N replicated and non-colluding databases where a user has an outdated version of the message W^θ of length L bits that differ from the current version Wθ in at most f bits. The user also has a cache containing coded combinations of the K messages (with a pre-specified structure), which are unknown to the N databases (unknown prefetching). The cache Z contains ℓ linear combinations from all K messages in the databases with r=lL being the caching ratio. The user needs to retrieve Wθ correctly using a private information retrieval (PIR) scheme without leaking information about the message index θ to any individual database. Our objective is to jointly design the prefetching (i.e., the structure of said linear combinations) and the PIR strategies to achieve the least download cost. We propose a novel achievable scheme based on syndrome decoding where the cached linear combinations in Z are designed to be bits pertaining to the syndrome of Wθ according to a specific linear block code. We derive a general lower bound on the optimal download cost for 0≤r≤1, in addition to achievable upper bounds. The upper and lower bounds match for the cases when r is exceptionally low or high, or when K=3 messages for arbitrary r. Such bounds are derived by developing novel cache-aided arbitrary message length PIR schemes. Our results show a significant reduction in the download cost if f<L2 when compared with downloading Wθ directly using typical cached-aided PIR approaches.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12385550/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Robust Unsupervised Feature Selection Algorithm Based on Fuzzy Anchor Graph. 基于模糊锚图的鲁棒无监督特征选择算法。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-08-04 DOI: 10.3390/e27080827

Zhouqing Yan, Ziping Ma, Jinlin Ma, Huirong Li

{"title":"Robust Unsupervised Feature Selection Algorithm Based on Fuzzy Anchor Graph.","authors":"Zhouqing Yan, Ziping Ma, Jinlin Ma, Huirong Li","doi":"10.3390/e27080827","DOIUrl":"https://doi.org/10.3390/e27080827","url":null,"abstract":"Unsupervised feature selection aims to characterize the cluster structure of original features and select the optimal subset without label guidance. However, existing methods overlook fuzzy information in the data, failing to model cluster structures between data effectively, and rely on squared error for data reconstruction, exacerbating noise impact. Therefore, a robust unsupervised feature selection algorithm based on fuzzy anchor graphs (FWFGFS) is proposed. To address the inaccuracies in neighbor assignments, a fuzzy anchor graph learning mechanism is designed. This mechanism models the association between nodes and clusters using fuzzy membership distributions, effectively capturing potential fuzzy neighborhood relationships between nodes and avoiding rigid assignments to specific clusters. This soft cluster assignment mechanism improves clustering accuracy and the robustness of the graph structure while maintaining low computational costs. Additionally, to mitigate the interference of noise in the feature selection process, an adaptive fuzzy weighting mechanism is presented. This mechanism assigns different weights to features based on their contribution to the error, thereby reducing errors caused by redundant features and noise. Orthogonal tri-factorization is applied to the low-dimensional representation matrix. This guarantees that each center represents only one class of features, resulting in more independent cluster centers. Experimental results on 12 public datasets show that FWFGFS improves the average clustering accuracy by 5.68% to 13.79% compared with the state-of-the-art methods.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12386169/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Complexity-Based Approach to Quantum Observable Equilibration. 基于复杂性的量子可观测平衡方法。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-08-03 DOI: 10.3390/e27080824

Marcos G Alpino, Tiago Debarba, Reinaldo O Vianna, André T Cesário

{"title":"A Complexity-Based Approach to Quantum Observable Equilibration.","authors":"Marcos G Alpino, Tiago Debarba, Reinaldo O Vianna, André T Cesário","doi":"10.3390/e27080824","DOIUrl":"https://doi.org/10.3390/e27080824","url":null,"abstract":"We investigate the role of a statistical complexity measure to assign equilibration in isolated quantum systems. While unitary dynamics preserve global purity, expectation values of observables often exhibit equilibration-like behavior, raising the question of whether a measure of complexity can track this process. In addition to examining observable equilibration, we extend our analysis to study how the complexity of the quantum states evolves, providing insight into the transition from initial coherence to equilibrium. We define a classical statistical complexity measure based on observable entropy and deviation from equilibrium, which captures the dynamical progression towards equilibration and effectively distinguishes between complex and non-complex trajectories. In particular, our measure is sensitive to non-complex dynamics. Such dynamics include the quasi-periodic behavior exhibited by low-dimensional initial states, where the system explores a limited region of Hilbert space while preserving coherence. Numerical simulations of an Ising-like non-integrable Hamiltonian spin-chain model support these findings. Our work provides new insight into the emergence of equilibrium behavior from unitary dynamics and advances complexity as a meaningful tool in the study of the emergence of classicality in microscopic systems.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12385702/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Linking Optimization Success and Stability of Finite-Time Thermodynamics Heat Engines. 链接有限时间热力学热机的优化成功与稳定性。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-08-02 DOI: 10.3390/e27080822

Julian Gonzalez-Ayala, David Pérez-Gallego, Alejandro Medina, José M Mateos Roco, Antonio Calvo Hernández, Santiago Velasco, Fernando Angulo-Brown

{"title":"Linking Optimization Success and Stability of Finite-Time Thermodynamics Heat Engines.","authors":"Julian Gonzalez-Ayala, David Pérez-Gallego, Alejandro Medina, José M Mateos Roco, Antonio Calvo Hernández, Santiago Velasco, Fernando Angulo-Brown","doi":"10.3390/e27080822","DOIUrl":"https://doi.org/10.3390/e27080822","url":null,"abstract":"In celebration of 50 years of the endoreversible Carnot-like heat engine, this work aims to link the thermodynamic success of the irreversible Carnot-like heat engine with the stability dynamics of the engine. This region of success is defined by two extreme configurations in the interaction between heat reservoirs and the working fluid. The first corresponds to a fully reversible limit, and the second one is the fully dissipative limit; in between both limits, the heat exchange between reservoirs and working fluid produces irreversibilities and entropy generation. The distance between these two extremal configurations is minimized, independently of the chosen metric, in the state where the efficiency is half the Carnot efficiency. This boundary encloses the region where irreversibilities dominate or the reversible behavior dominates (region of success). A general stability dynamics is proposed based on the endoreversible nature of the model and the operation parameter in charge of defining the operation regime. For this purpose, the maximum ecological and maximum Omega regimes are considered. The results show that for single perturbations, the dynamics rapidly directs the system towards the success region, and under random perturbations producing stochastic trajectories, the system remains always in this region. The results are contrasted with the case in which no restitution dynamics exist. It is shown that stability allows the system to depart from the original steady state to other states that enhance the system's performance, which could favor the evolution and specialization of systems in nature and in artificial devices.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12386041/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Localizing Synergies of Hidden Factors in Complex Systems: Resting Brain Networks and HeLa GeneExpression Profile as Case Studies. 复杂系统中隐藏因素的局部协同作用：静息脑网络和HeLa基因表达谱作为案例研究。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-08-01 DOI: 10.3390/e27080820

Marlis Ontivero-Ortega, Gorana Mijatovic, Luca Faes, Fernando E Rosas, Daniele Marinazzo, Sebastiano Stramaglia

{"title":"Localizing Synergies of Hidden Factors in Complex Systems: Resting Brain Networks and HeLa GeneExpression Profile as Case Studies.","authors":"Marlis Ontivero-Ortega, Gorana Mijatovic, Luca Faes, Fernando E Rosas, Daniele Marinazzo, Sebastiano Stramaglia","doi":"10.3390/e27080820","DOIUrl":"https://doi.org/10.3390/e27080820","url":null,"abstract":"Factor analysis is a well-known statistical method to describe the variability of observed variables in terms of a smaller number of unobserved latent variables called factors. Even though latent factors are conceptually independent of each other, their influence on the observed variables is often joint and synergistic. We propose to quantify the synergy of the joint influence of factors on the observed variables using O-information, a recently introduced metric to assess high-order dependencies in complex systems; in the proposed framework, latent factors and observed variables are jointly analyzed in terms of their joint informational character. Two case studies are reported: analyzing resting fMRI data, we find that DMN and FP networks show the highest synergy, consistent with their crucial role in higher cognitive functions; concerning HeLa cells, we find that the most synergistic gene is STK-12 (AURKB), suggesting that this gene is involved in controlling the HeLa cell cycle. We believe that our approach, representing a bridge between factor analysis and the field of high-order interactions, will find wide application across several domains.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12386147/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Finite-Time Thermodynamics and Complex Energy Landscapes: A Perspective. 有限时间热力学和复杂能量景观：一个视角。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-08-01 DOI: 10.3390/e27080819

Johann Christian Schön

{"title":"Finite-Time Thermodynamics and Complex Energy Landscapes: A Perspective.","authors":"Johann Christian Schön","doi":"10.3390/e27080819","DOIUrl":"https://doi.org/10.3390/e27080819","url":null,"abstract":"Finite-time thermodynamics (FTT) describes the study of thermodynamic processes that take place in finite time. Due to the finite-time requirement, in general the system cannot move from equilibrium state to equilibrium state. As a consequence, excess entropy is generated, available work is reduced, and/or the maximally achievable efficiency is not achieved; minimizing these negative side-effects constitutes an optimal control problem. Particularly challenging are processes and cycles that involve phase transitions of the working fluid material or the target material of a synthesis process, especially since most materials reside on a highly complex energy landscape exhibiting alternative metastable phases or glassy states. In this perspective, we discuss the issues and challenges involved in dealing with such materials when performing thermodynamic processes that include phase transitions in finite time. We focus on thermodynamic cycles with one back-and-forth transition and the generation of new materials via a phase transition; other systems discussed concern the computation of free energy differences and the general applicability of FTT to systems outside the realm of chemistry and physics that exhibit cost function landscapes with phase transition-like dynamics.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12385517/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

G-Subdiffusion Equation as an Anomalous Diffusion Equation Determined by the Time Evolution of the Mean Square Displacement of a Diffusing Molecule. g -亚扩散方程是由扩散分子均方位移的时间演化决定的反常扩散方程。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-07-31 DOI: 10.3390/e27080816

Tadeusz Kosztołowicz, Aldona Dutkiewicz, Katarzyna D Lewandowska

引用次数: 0

Machine Learning-Assisted Secure Random Communication System. 机器学习辅助安全随机通信系统。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-07-29 DOI: 10.3390/e27080815

Areeb Ahmed, Zoran Bosnić

{"title":"Machine Learning-Assisted Secure Random Communication System.","authors":"Areeb Ahmed, Zoran Bosnić","doi":"10.3390/e27080815","DOIUrl":"https://doi.org/10.3390/e27080815","url":null,"abstract":"Machine learning techniques have revolutionized physical layer security (PLS) and provided opportunities for optimizing the performance and security of modern communication systems. In this study, we propose the first machine learning-assisted random communication system (ML-RCS). It comprises a pretrained decision tree (DT)-based receiver that extracts binary information from the transmitted random noise carrier signals. The ML-RCS employs skewed alpha-stable (α-stable) noise as a random carrier to encode the incoming binary bits securely. The DT model is pretrained on an extensively developed dataset encompassing all the selected parameter combinations to generate and detect the α-stable noise signals. The legitimate receiver leverages the pretrained DT and a predetermined key, specifically the pulse length of a single binary information bit, to securely decode the hidden binary bits. The performance evaluations included the single-bit transmission, confusion matrices, and a bit error rate (BER) analysis via Monte Carlo simulations. The fact that the BER reached 10-3 confirms the ability of the proposed system to establish successful secure communication between a transmitter and legitimate receiver. Additionally, the ML-RCS provides an increased data rate compared to previous random communication systems. From the perspective of security, the confusion matrices and computed false negative rate of 50.2% demonstrate the failure of an eavesdropper to decode the binary bits without access to the predetermined key and the private dataset. These findings highlight the potential ability of unconventional ML-RCSs to promote the development of secure next-generation communication devices with built-in PLSs.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12386027/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Harnessing the Power of Pre-Trained Models for Efficient Semantic Communication of Text and Images. 利用预训练模型的力量进行文本和图像的有效语义交流。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-07-29 DOI: 10.3390/e27080813

Emrecan Kutay, Aylin Yener

{"title":"Harnessing the Power of Pre-Trained Models for Efficient Semantic Communication of Text and Images.","authors":"Emrecan Kutay, Aylin Yener","doi":"10.3390/e27080813","DOIUrl":"https://doi.org/10.3390/e27080813","url":null,"abstract":"This paper investigates point-to-point multimodal digital semantic communications in a task-oriented setup, where messages are classified at the receiver. We employ a pre-trained transformer model to extract semantic information and propose three methods for generating semantic codewords. First, we propose semantic quantization that uses quantized embeddings of source realizations as a codebook. We investigate the fixed-length coding, considering the source semantic structure and end-to-end semantic distortion. We propose a neural network-based codeword assignment mechanism incorporating codeword transition probabilities to minimize the expected semantic distortion. Second, we present semantic compression that clusters embeddings, exploiting the inherent semantic redundancies to reduce the codebook size, i.e., further compression. Third, we introduce a semantic vector-quantized autoencoder (VQ-AE) that learns a codebook through training. In all cases, we follow this semantic source code with a standard channel code to transmit over the wireless channel. In addition to classification accuracy, we assess pre-communication overhead via a novel metric we term system time efficiency. Extensive experiments demonstrate that our proposed semantic source-coding approaches provide comparable accuracy and better system time efficiency compared to their learning-based counterparts.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":"27 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12385560/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144947244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Causally-Informed Instance-Wise Feature Selection for Explaining Visual Classifiers. 用于解释视觉分类器的因果通知实例智能特征选择。

IF 2 3区物理与天体物理

Entropy Pub Date : 2025-07-29 DOI: 10.3390/e27080814

Li Tan

引用次数: 0