检索结果-内蒙古大学图书馆

CIRFE: A Distributed Random Fields Estimator

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2018年第18期66卷 4980-4995页

作者： Sahu, Anit Kumar Jakovetic, Dusan Kar, Soummya Carnegie Mellon Univ Dept Elect & Comp Engn Pittsburgh PA 15213 USA Univ Novi Sad Fac Sci Dept Math & Informat Novi Sad 21000 Serbia

The paper presents a communication efficient distributed algorithm, CIRFE of the consensus+innovations type, to estimate a high-dimensional parameter in a multi-agent network, in which each agent is interested in reconstructing only a few components of the parameter. This problem arises, for example, when monitoring the high-dimensional distributed state of a large-scale infrastructure with a network of limited capability sensors and where each sensor is tasked with estimating some local components of the state. At each observation sampling epoch, each agent updates its local estimate of the parameter components in its interest set by simultaneously processing the latest locally sensed information (innovations) and the parameter estimates from agents (consensus) in its communication neighborhood given by a time-varying possibly sparse graph. Under minimal conditions, on the interagent communication network and the sensing models, almost sure convergence of the estimate sequence at each agent to the components of the true parameter in its interest set is established. Furthermore, the paper establishes the performance of CIRFE in terms of asymptotic covariance of the estimate sequences and specifically characterizes the dependencies of the component wise asymptotic covariance in terms of the number of agents tasked with estimating it. Finally, simulation experiments demonstrate the efficacy of CIRFE.

关键词： Distributed estimation consensus algorithms distributed inference random fields stochastic approximation

来源：评论

学校读者我要写书评

暂无评论

Robust Distributed Secondary Voltage Restoration Control of AC Microgrids under Multiple Communication Delays

引用

ENERGIES 2021年第4期14卷 1165页

作者： Gholami, Milad Pilloni, Alessandro Pisano, Alessandro Usai, Elio Univ Cagliari Dept Elect & Elect Engn DIEE I-09123 Cagliari Italy

This paper focuses on the robust distributed secondary voltage restoration control of AC microgrids (MGs) under multiple communication delays and nonlinear model uncertainties. The problem is addressed in a multi-agent fashion where the generators' local controllers play the role of cooperative agents communicating over a network and where electrical couplings among generators are interpreted as disturbances to be rejected. Communications are considered to be affected by heterogeneous network-induced time-varying delays with given upper-bounds and the MG is subjected to nonlinear model uncertainties and abrupt changes in the operating working condition. Robustness against uncertainties is achieved by means of an integral sliding mode control term embedded in the control protocol. Then, the global voltage restoration stability, despite the communication delays, is demonstrated through a Lyapunov-Krasovskii analysis. Given the delays' bounds, and because the resulting stability conditions result in being non-convex with respect to the controller gain, then a relaxed linear matrix inequalities-based tuning criteria is developed to maximize the controller tuning, thus minimizing the restoration settling-time. By means of that, a criteria to estimate the maximal delay margin tolerated by the system is also provided. Finally, simulations on a faithful nonlinear MG model, showing the effectiveness of the proposed control strategy, are further discussed.

关键词： microgrid voltage control multi-agent systems secondary control sliding mode control time delay systems consensus algorithms linear matrix inequalities

来源：评论

学校读者我要写书评

暂无评论

Beyond Bitcoin: Evaluating Energy Consumption and Environmental Impact across Cryptocurrency Projects

引用

ENERGIES 2023年第18期16卷 6610页

作者： Khosravi, Ali Saamaki, Fanni Univ Southern Denmark Ctr Ind Mech CIM Dept Mech & Elect Engn DK-6400 Sonderborg Denmark Aalto Univ Sch Engn Dept Mech Engn Espoo 02150 Finland

Since their inception with Bitcoin in the late 2000s, cryptocurrencies have grown exponentially, reshaping traditional financial paradigms. This transformative journey, while innovative, brings forth pressing concerns about their energy consumption and carbon footprint. While many studies tend to zoom in on Bitcoin, this paper broadens the perspective by evaluating energy consumption across various cryptocurrencies. We analyze nine cryptocurrency projects, chosen for their market value, technology, and data availability. These span a spectrum from pioneering to emerging digital coins, offering a holistic view of the crypto realm. To contextualize, we juxtapose the energy usage of these digital currencies with traditional payment means like Visa and Mastercard. Our analysis shows vast differences in energy use among cryptocurrencies, largely tied to their consensus algorithms. Notably, while Bitcoin stands out as highly energy-intensive, several newer digital currencies have energy footprints mirroring those of conventional payment methods. Additionally, CO2 emissions estimation presents challenges due to variances in miner locations and regional energy sources, with potential higher emissions if concentrated in carbon-intensive regions like China. Nonetheless, the silver lining emerges as many cryptocurrencies, especially those beyond Bitcoin, register considerably lower CO2 emissions. By moving the lens beyond Bitcoin, this paper paints a more nuanced picture of the environmental ramifications of the crypto world.

关键词： energy consumption bitcoin cryptocurrency CO2 emissions consensus algorithms

来源：评论

学校读者我要写书评

暂无评论

Blockchain for healthcare systems: Architecture, security challenges, trends and future directions

引用

JOURNAL OF NETWORK AND COMPUTER APPLICATIONS 2023年第1期215卷

作者： Andrew, J. Isravel, Deva Priya Sagayam, K. Martin Bhushan, Bharat Sei, Yuichi Eunice, Jennifer Manipal Acad Higher Educ Manipal Inst Technol Dept Comp Sci & Engn Manipal 576104 Karnataka India Karunya Inst Technol & Sci Dept Comp Sci & Engn Coimbatore 641114 Tamil Nadu India Karunya Inst Technol & Sci Dept Elect & Commun Engn Coimbatore 641114 Tamil Nadu India Sharda Univ Sch Engn & Technol Dept Comp Sci & Engn Greater Noida 201310 Uttar Pradesh India Univ Electrocommun Dept Informat Chofu 1828585 Japan

Blockchain has become popular in recent times through its data integrity and wide scope of applications. It has laid the foundation for cryptocurrencies such as Ripple, Bitcoin, Ethereum, and so on. Blockchain provides a platform for decentralization and trust in various applications such as finance, commerce, IoT, reputation sys-tems, and healthcare. However, prevailing challenges like scalability, resilience, security and privacy are yet to be overcome. Due to rigorous regulatory constraints such as HIPAA, blockchain applications in the healthcare industry usually require more stringent authentication, interoperability, and record sharing requirements. This article presents an extensive study to showcase the significance of blockchain technology from both application and technical perspectives for healthcare domain. The article discusses the features and use-cases of blockchain in different applications along with the healthcare domain interoperability. The detailed working operation of the blockchain and the consensus algorithms are presented in the context of healthcare. An outline of the blockchain architecture, platforms, and classifications are discussed to choose the right platform for healthcare applications. The current state-of-the-art research in healthcare blockchain and available blockchain based healthcare applications are summarized. Furthermore, the challenges and future research opportunities along with the performance evaluation metrics in realizing the blockchain technology for healthcare are presented to provide insight for future research. We also layout the various security attacks on the blockchain protocol with the classifications of threat models and presented a comparative analysis of the detection and protection tech-niques. Techniques to enhance the security and privacy of the blockchain network is also discussed.

关键词： Blockchain consensus algorithms Cryptocurrency Distributed ledger Healthcare data Security & privacy

来源：评论

学校读者我要写书评

暂无评论

A survey of empirical performance evaluation of permissioned blockchain platforms: Challenges and opportunities

引用

COMPUTERS & SECURITY 2021年 100卷 102078-102078页

作者： Dabbagh, Mohammad Choo, Kim-Kwang Raymond Beheshti, Amin Tahir, Mohammad Safa, Nader Sohrabi Sunway Univ Sch Sci & Technol Petaling Jaya 47500 Selangor Malaysia Univ Texas San Antonio Dept Informat Syst & Cyber Secur San Antonio TX 78249 USA Macquarie Univ Dept Comp Sydney NSW Australia Coventry Univ Sch Comp Elect & Math Coventry W Midlands England

Blockchain-based platforms, particularly those based on permissioned blockchain, are increasingly popular in a broad range of settings. In addition to security and privacy concerns, organizations seeking to implement such platforms also need to consider performance, especially in latencyor delay-sensitive applications. Performance is generally less studied in comparison to security and privacy, and therefore in this paper we survey existing empirical performance evaluations of different permissioned blockchain platforms published between 2015 and 2019, using a comparative framework. The framework comprises ten criteria. We then conclude the paper with a number of potential future research directions. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Permissioned blockchain Performance evaluation Distributed ledger consensus algorithms Decentralized Platforms

来源：评论

学校读者我要写书评

暂无评论

On The Relation Between Port-Hamiltonian And Gradient Systems

引用

IFAC Proceedings Volumes 2011年第1期44卷 3321-3326页

作者： A.J. van der Schaft Johann Bernoulli Institute for Mathematics and Computer Science University of Groningen PO Box 407 9700 AK the Netherlands

Abstract In this paper we investigate the relationships between port-Hamiltonian and gradient systems; primarily in the linear case. We show how the combination of the property of passivity with that of a gradient system leads to a class of systems which can be directly related to the classical Brayton-Moser description of RLC circuits.

关键词： Passivity reciprocity storage functions potential functions indefinite innner products Brayton-Moser equations RLC-circuits consensus algorithms Hessian Riemannian metrics

来源：评论

学校读者我要写书评

暂无评论

Cooperative source seeking via networked multi-vehicle systems

引用

AUTOMATICA 2020年第0期115卷 108853-000页

作者： Li, Zhuo You, Keyou Song, Shiji Tsinghua Univ Dept Automat Beijing 100084 Peoples R China Tsinghua Univ BNRist Beijing 100084 Peoples R China

This paper studies the cooperative source seeking problem via a networked multi-vehicle system. In contrast to existing literature, the multi-vehicle system is controlled to the source position that maximizes aggregated multiple unknown scalar fields and each sensor-enabled vehicle only samples measurements of one scalar field. Thus, a single vehicle is unable to localize the source and has to cooperate with its neighboring vehicles. By jointly exploiting the ideas of the consensus algorithm and the stochastic extremum seeking (ES), this paper proposes novel distributed stochastic ES controllers, which are gradient-free and do not need any absolute information, such that the multi-vehicle system simultaneously approaches the source position. The effectiveness of the proposed controllers is proved for quadratic scalar fields. Finally, illustrative examples are included to validate the theoretical results. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Cooperative source seeking Scalar field Multi-vehicle systems consensus algorithms Stochastic ES

来源：评论

学校读者我要写书评

暂无评论

Miner Selection in an Internet of Medical Things Framework using Fuzzy Logic

引用

APPLIED SOFT COMPUTING 2024年 161卷

作者： Singh, Namrata Das, Ayan Kumar Sinha, Ditipriya Birla Inst Technol Patna Campus Mesra Bihar India Natl Inst Technol Patna Patna Bihar India

Blockchain-enabled Internet of Medical Things (IoMT) is a secure, transparent, and decentralized network of medical devices which facilitates a patient-centric healthcare system for distributed exchange and management of medical records. The existing consensus protocols designed for a blockchain network such as Proof-of-Work, Proof-of-Stake, Proof-of-Negotiation, Proof-of-Authority, and Proof-of-X-Repute lack fast processing and security. This paper presents a scalable blockchain-enabled IoMT framework that uses gateway nodes to improve the performance. A novel hybrid consensus mechanism namely Proof-of-Context (PoCt) is also proposed for blockchain-enabled IoMT environment. The proposed PoCt consensus is a fast, reliable, and secure mechanism for block mining which consists of a fuzzy-based miner selection and a block validation process with multiple parameters. Fuzzy-based miner selection is done on the basis of context factor of a node, which is computed using the impact score, vote count and trust value. The trusted miner nodes are responsible for block generation and validation. The most trusted and efficient miner node having the highest neighbour density is being selected for block generation. The other miner nodes are responsible for block validation to prevent various malicious activities. The performance analysis of the PoCt consensus shows that it is comparatively 24% more efficient, 36% faster, 1.8% more reliable, and 65% less traffic overhead than fuzzy-based super leader nomination in PoS consensus mechanism, 65% faster than random-voting and game-theory based miner selection, 25% faster than Proof-of-Negotiation consensus, 6.1% more reliable and 58% less traffic overhead than Proof-of-Authority consensus mechanism for the network of 500 nodes. Security analysis of PoCt consensus algorithm ensures its resilience against various known mining attacks.

关键词： IoMT Blockchain Fuzzy logic Miner selection consensus algorithms

来源：评论

学校读者我要写书评

暂无评论

Modelling the steady-state of secondary control in islanded AC microgrids

引用

INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2023年第1期153卷

作者： Pompodakis, Evangelos E. Tinajero, Gibran D. A. Karapidakis, Emmanuel S. Hellen Mediterranean Univ Crete Inst Energy Environm & Climat Change Iraklion Greece Aalborg Univ Fac Engn & Sci Elect Power Syst & Microgrids Aalborg Denmark Hellen Mediterranean Univ Sch Engn Khania Greece

The secondary control is applied in islanded Microgrids (MGs), after the primary control, in order to restore the voltages and frequency to specified values. Although existing power flow methods can accurately calculate the power flow of primary and tertiary control of islanded MGs, they present considerable limitations in the modelling of secondary control. The main challenge is that secondary controllers consist of integral parts, which under communication failures, could integrate functions with different integral histories, and thus, can imply non-uniform power production of distributed generators (DGs). This paper proposes a power flow method for calculating, accurately, the steady-state of secondary control in islanded MGs. The method has four distinct features: a) generalized implementation in several communication strategies e.g., centralized, decentralized, consensus, distributed averaging, b) precise simulation of communication links and proportional-integral (PI) controllers, c) low computation time, and d) accurate three-phase network representation. Simulations were executed to validate the proposed method and highlight the importance of modelling, precisely, the secondary control in islanded MGs.

关键词： Communication failures consensus algorithms Cyberattacks Frequency and voltage restoration Hierarchical control Islanded microgrids Power flow Secondary control

来源：评论

学校读者我要写书评

暂无评论

Distributed moving horizon estimation for nonlinear constrained systems

引用

IFAC Proceedings Volumes 2010年第14期43卷 909-914页

作者： Marcello Farina Giancarlo Ferrari-Trecate Riccardo Scattolini Dipartimento di Elettronica e Informazione Politecnico di Milano Via Ponzio 34/5 20133 Milan Italy Dipartimento di Informatica e Sistemistica Università degli Studi di Pavia Via Ferrata 1 27100 Pavia Italy

In this paper we consider a nonlinear constrained system observed by a sensor network and propose a distributed state estimation scheme based on Moving Horizon Estimation (MHE). In order to embrace the case where the whole system state cannot be reconstructed from data available to individual sensors, we resort to the notion of MHE-detectability for nonlinear systems, and add to the MHE problems solved by each sensor a consensus term for propagating information about estimates through the network. Under some suitable assumptions we prove convergence to zero and stability of the state estimation error provided by any sensor.

关键词： Distributed estimation moving horizon estimation consensus algorithms nonlinear systems detectability

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：