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Revisiting the Relative Performance of the AVL Tree and Three Variants of the Red-Black Tree

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arXiv 2024年

作者： Brown, Russell A.

Although historical opinion has held that the red-black tree is faster than the AVL tree, benchmarks reveal that the AVL tree is faster than the red-black tree for deletion, often faster for insertion, and as fast or faster for search. Both trees achieve O (log n) insertion, deletion, and search by rebalancing in association with insertion and deletion. An improved AVL tree deletion algorithm reduces the rebalancing operations associated with deletion by 20 percent. Copyright © 2024, The Authors. All rights reserved.

关键词： consensus algorithm

An Improved Distributed Secondary Control Scheme in Islanded AC Microgrids

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An Improved Distributed Secondary Control Scheme in Islanded...

IEEE Energy Conversion Congress and Exposition

作者： Jiahao Yu Fei Gao Shanshan Wei Junzhong Xu Dawei Liao Yutong Zhao Key Laboratory of Control of Power Transmission and Conversion Ministry of Education Shanghai Jiao Tong University Shanghai China

ISBN: (数字)9781728158266

ISBN: (纸本)9781728158273

Following the hierarchical control architecture, this paper investigates the diffusion algorithm based distributed secondary control in islanded AC microgrids. The principle of diffusion algorithm is introduced first and then diffusion algorithm-based distributed secondary control strategies are analyzed in details. Compared to the conventional consensus algorithm employed in the secondary control, it is shown that diffusion algorithm shows a faster convergence and a smaller deviation from the nominal value. A three-node islanded AC MG is simulated and the results confirm that the proposed diffusion-based secondary control outperforms consensus-based approach in terms of voltage/frequency restoration.

关键词： Voltage control Inverters Eigenvalues and eigenfunctions Power transmission Education consensus algorithm Topology

Vulnerability Assessment of Blockchain Using Confrontation Deduction

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Vulnerability Assessment of Blockchain Using Confrontation D...

Chinese Automation Congress (CAC)

作者： Luyu Chen Jing He Xiaofeng Ma Wei Ye School of Electronics and Information Engineering Toingji University Shangha China Suzhou Tongji Blockchain Research Institute Suzhou China

ISBN: (纸本)9781665426480

blockchain technology is one of the strategic emerging information technologies. It integrates a variety of technologies such as cryptography, peer-to-peer network, consensus algorithm and smart contract, and has been gradually applied in various fields. The contradiction between the rapid development of blockchain industry and the incompleteness of evaluation system and technical means has become increasingly prominent. The vulnerability of blockchain system is an important part of blockchain evaluation system. It is of great significance for the development of blockchain technology and large-scale application to fully study the vulnerability of blockchain system and conduct quantitative evaluation or real-time monitoring. This paper systematically analyzes the vulnerability of blockchain, and puts forward the technical indicators to evaluate the vulnerability of blockchain. Based on the vulnerability technical index of blockchain consensus algorithm and industrial blockchain consensus algorithm PBFT, a consensus algorithm confrontation deduction model is designed, and the vulnerability index of blockchain system using PBFT is experimentally simulated and evaluated.

关键词： Fault tolerance Simulation Fault tolerant systems Smart contracts consensus algorithm Real-time systems Blockchains

Ethereum for Secure Authentication of IoT using Pre-Shared Keys (PSKs)

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Ethereum for Secure Authentication of IoT using Pre-Shared K...

International Conference on Wireless Networks and Mobile Communications (WINCOM)

作者： Mohammad El-Hajj Ahmad Fadlallah Maroun Chamoun Ahmed Serhrouchni Saint Joseph University Lebanon University of Sciences and Arts in Lebanon Telecom ParisTech France

Enterprises are no doubt interested in reaching data collected from billions of Internet of Things (IoT) devices which opens a huge potential business. The main concern remains the security challenges from the distribution of key while using public key cryptography. To ensure that IOT connected devices can be trusted to be what they are supposed to be, robust IoT device authentication is mandated. Each IoT device therefore requires a unique identity which can be verified when the device tries to link to an intermediate device. One of the early solutions used to secure data transmission among parties in public networks is the Public Key Infrastructure (PKI) which is used to distribute and manage public keys (digital certificates) among different parties and these certificates are generated upon request by Certificate Authorities (CA). Nevertheless, for billions of devices connected to IoT and mobile phones, the distribution management of certificates for each client proved to be inefficient. In this research, we propose a decentralized authentication platform based on PKI and Ethereum Blockchain. The public key certificates are stored in a decentralized fashion and the private keys are stored inside the devices themselves. It also includes a protocol for Pre-Shared Keys (PSK) distribution. PSK keys are then used by PSK-based security protocols for securing the communication channel between two devices. This platform includes a client-side module, a server-side Wallet Management Function, and a smart contract deployed on the Ethereum Blockchain network. This platform can be used by applications for end devices and/or intermediate devices authentication and a secure Machine-to-Machine (M2M) communication. The proposed platform is validated by the implementation of a Secure Session Establishment between IoT devices. Results show that the solution implementation has minimal impact on the existing networks, and the secure session setup time between two devices is negligib

关键词： Blockchain consensus algorithm Authentication Public key Smart contracts

Smart GuardianChain: A Solution Based on Blockchain Technology for Ensuring Security of E-Health Records in a Smart Environment

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Smart GuardianChain: A Solution Based on Blockchain Technolo...

Smart Devices (ICSD), International Conference on

作者： Vinod Sharma Kailash Aseri Ranadeep Reddy Palle Atul Agrawal Karthikeya Tallapneni Sourabh Kumar Jain Jiwaji University Sunrise University University of Houston SDBCT Chandigarh University Jayoti Vidyapeeth Women’s University

ISBN: (数字)9798350394412

ISBN: (纸本)9798350394429

In the age of rapidly progressing technology, the healthcare sector is embracing the revolution of digital transformation through the widespread adoption of Electronic Health Records (EHRs). Nevertheless, the digital realm also presents notable challenges, particularly pertaining to the security and confidentiality of patients' delicate health data. This document introduces the innovative Smart GuardianChain, a blockchain-based distributed system crafted to tackle these pivotal concerns by establishing an infallible, decentralized, and impervious platform for the management and sharing of *** GuardianChain capitalizes on a robust consensus algorithm to ensure the integrity of EHRs, thus safeguarding the genuineness of medical records in an increasingly interconnected healthcare ecosystem. To guarantee that solely authorized entities have access to patient information, the system integrates an intricate mechanism for access control. Patients are bestowed with complete authority over their EHRs, enabling them to manage access permissions as they deem appropriate. Through extensive experimentation, our results demonstrate the scalability, efficiency, and effectiveness of the proposed system, which not only enhances security but also preserves patient privacy. By addressing the pressing privacy challenges that EHR systems face today, Smart GuardianChain stands poised to revolutionize the quality of healthcare services, fostering trust and confidence in the digital healthcare landscape.

关键词： Industries Data privacy Privacy Vegetation mapping Land surface Medical services consensus algorithm Radiometry Electronic medical records Remote sensing

Sequential and Simultaneous Distance-based Dimension Reduction

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arXiv 2019年

作者： Ni, Yijin Yu, Chuanping Ko, Andy Huo, Xiaoming H. Milton Stewart School of Industrial and Systems Engineering Georgia Institute of Technology United States

This paper introduces a method called Sequential and Simultaneous Distance-based Dimension Reduction (S2D2R) that performs simultaneous dimension reduction for a pair of random vectors based on distance covariance (dCov). Compared with sufficient dimension reduction (SDR) and canonical correlation analysis (CCA)-based approaches, S2D2R is a model-free approach that does not impose dimensional or distributional restrictions on variables and is more sensitive to nonlinear relationships. Theoretically, we establish a non-asymptotic error bound to guarantee the performance of S2D2R. Numerically, S2D2R performs comparable to or better than other state-of-the-art algorithms and is computationally faster. All codes of our S2D2R method can be found on, including an R package named S2D2R. Copyright © 2019, The Authors. All rights reserved.

关键词： consensus algorithm

Efficient Matroid Intersection via a Batch-Update Auction algorithm

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arXiv 2024年

作者： Blikstad, Joakim Tu, Ta-Wei KTH Royal Institute of Technology Max Planck Institute for Informatics Sweden Stanford University United States

Given two matroidsM1 andM2 over the same n-element ground set, the matroid intersection problem is to find a largest common independent set, whose size we denote by r. We present a simple and generic auction algorithm that reduces (1 - ϵ)-approximate matroid intersection to roughly 1/ϵ2 rounds of the easier problem of finding a maximum-weight basis of a single matroid. Plugging in known primitives for this subproblem, we obtain both simpler and improved algorithms in two models of computation, including: The first near-linear time/independence-query (1 - ϵ)-approximation algorithm for matroid intersection. Our randomized algorithm uses1 O(n/ϵ + r/ϵ5) independence queries, improving upon the previous O(n/ϵ + r √ r/ϵ3) bound of Quanrud (2024). The first sublinear exact parallel algorithms for weighted matroid intersection, using O(n2/3) rounds of rank queries or O(n5/6) rounds of independence queries. For the unweighted case, our results improve upon the previous O(n3/4)-round rank-query and O(n7/8)-round independence-query algorithms of Blikstad (2022). Copyright © 2024, The Authors. All rights reserved.

关键词： consensus algorithm

Research on target recognition method of robotic arm based on improved ORB

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Research on target recognition method of robotic arm based o...

Chinese Control and Decision Conference, CCDC

作者： Zikang Gao Ming Lv Jie Zhang Nanjing University of Science and Technology Nanjing China

ISBN: (数字)9798350387780

ISBN: (纸本)9798350387797

When a robotic arm is in motion, it typically cannot intelligently perform complex tasks in response to changes in the surrounding environment. Introducing a vision-based spatial target recognition method enables the robotic arm to accurately acquire spatial information about the environment, laying the foundation for autonomous execution of intricate tasks by the robotic arm. Therefore, this paper investigates vision-based spatial target recognition methods. The approach employed utilizes template matching based on descriptors. The feature point extraction is accomplished through the application of the Improved ORB (Oriented FAST and Rotated BRIEF) image feature extraction algorithm. Furthermore, an improved GMS (Grid-based motion statistics) fusion MLESAC (Maximum Likelihood Estimator Sample consensus) algorithm is used to accomplish the matching between the captured image and the template image. The research results demonstrate that the proposed method can achieve accurate, rapid, and stable target recognition.

关键词： Maximum likelihood estimation Accuracy Target recognition Error analysis consensus algorithm Feature extraction Manipulators

The Cost of Consistency: Submodular Maximization with Constant Recourse

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arXiv 2024年

作者： Dütting, Paul Fusco, Federico Lattanzi, Silvio Norouzi-Fard, Ashkan Svensson, Ola Zadimoghaddam, Morteza Google Research United States Sapienza University of Rome Italy École Polytechnique Fédérale de Lausanne Switzerland

In this work, we study online submodular maximization, and how the requirement of maintaining a stable solution impacts the approximation. In particular, we seek bounds on the best-possible approximation ratio that is attainable when the algorithm is allowed to make at most a constant number of updates per step. We show a tight information-theoretic bound of 2/3 for general monotone submodular functions, and an improved (also tight) bound of 3/4 for coverage functions. Since both these bounds are attained by non poly-time algorithms, we also give a poly-time randomized algorithm that achieves a 0.51-approximation. Combined with an information-theoretic hardness of 1/2 for deterministic algorithms from prior work, our work thus shows a separation between deterministic and randomized algorithms, both information theoretically and for poly-time algorithms. © 2024, CC BY.

关键词： consensus algorithm