Distributed algorithm

About: Distributed algorithm is a research topic. Over the lifetime, 20416 publications have been published within this topic receiving 548109 citations.

Distributed program checking: a paradigm for building self-stabilizing distributed protocols

Abstract: The notion of distributed program checking as a means of making a distributed algorithm self-stabilizing is explored. A compiler that converts a deterministic synchronous protocol pi for static networks into a self-stabilizing version of pi for dynamic networks is described. If T/sub pi / is the time complexity of pi and D is a bound on the diameter of the final network, the compiled version of pi stabilizes in time O(D+T/sub pi /) and has the same space complexity as pi . The general method achieves efficient results for many specific noninteractive tasks. For instance, solutions for the shortest paths and spanning tree problems take O(D) to stabilize, an improvement over the previous best time of O(D/sup 2/). >

Cooperative platoon control for a mixed traffic flow including human drive vehicles and connected and autonomous vehicles

Abstract: This study seeks to develop a cooperative platoon control for a platoon mixed with connected and autonomous vehicles (CAVs) and human-drive vehicles (HDVs), aiming to ensure system level traffic flow smoothness and stability as well as individual vehicles’ mobility and safety. Specifically, our study integrated/contributed the following technical approaches. First, the car-following behavior of human-drive vehicles is modeled by well-accepted Newell car-following models. Accordingly, an online curve matching algorithm is integrated to anticipate the aggregated response delay of the human-drive vehicles using real-time trajectory data. Built upon that, constrained One- or P-step MPC models are developed to control the movement of the CAV platoon upstream or downstream of the HDV platoon so that we can ensure both transient traffic smoothness and asymptotic stability of this sample mixed flow platoon, leveraging the communication and computation technologies equipped on CAVs. Considering the lack of the centralized computation facilities and severe changes of the platoon topology, this study develops a distributed algorithm to solve the MPCs according to the properties of the optimizers, such as solution uniqueness, sequentially feasibility, and nonempty interior point of the solution space. The convergence of the distributed algorithm as well as the stability of the MPC control is proved by both the theoretical analysis and the experimental study. Extensive numerical experiments based on the field data indicate that the distributed algorithm can solve the One-step and P-step MPCs efficiently. The cooperative MPC can dampen traffic oscillation propagation and stabilize the traffic flow more efficiently for the entire mixed flow platoon. Moreover, the cooperative platoon control scheme outperforms the other three control strategies, including the non-cooperative control strategy and a latest CACC strategy in literature.

A decentralized algorithm for spectral analysis

Abstract: In many large network settings, such as computer networks, social networks, or hyperlinked text documents, much information can be obtained from the network's spectral properties. However, traditional centralized approaches for computing eigenvectors struggle with at least two obstacles: the data may be difficult to obtain (both due to technical reasons and because of privacy concerns), and the sheer size of the networks makes the computation expensive. A decentralized, distributed algorithm addresses both of these obstacles: it utilizes the computational power of all nodes in the network and their ability to communicate, thus speeding up the computation with the network size. And as each node knows its incident edges, the data collection problem is avoided as well.Our main result is a simple decentralized algorithm for computing the top k eigenvectors of a symmetric weighted adjacency matrix, and a proof that it converges essentially in O(τMIXlog2n) rounds of communication and computation, where τMIX is the mixing time of a random walk on the network. An additional contribution of our work is a decentralized way of actually detecting convergence, and diagnosing the current error. Our protocol scales well, in that the amount of computation performed at any node in any one round, and the sizes of messages sent, depend polynomially on k, but not on the (typically much larger) number n of nodes.

Miche: Modular Shape Formation by Self-Disassembly

Abstract: We describe the design, implementation and programming of a set of robots that, starting from an amorphous arrangement, can be assembled into arbitrary shapes and then commanded to self-disassemble in an organized manner to obtain a goal shape. We present custom hardware, distributed algorithms and experimental results from hundreds of trails which show the system successfully forming complex 3D shapes. Each of the 28 modules in the system is implemented as a 1.8-inch autonomous cube-shaped robot able to connect to and communicate with its immediate neighbors. Embedded microprocessors control each module's magnetic connection mechanisms and infrared communication interfaces. When assembled into a structure, the modules form a system that can be virtually sculpted using a computer interface and a distributed process. The group of modules collectively decides which elements are a part of the final shape and which are not using algorithms that minimize information transmission and storage. Finally, the modules not in the structure disengage their magnetic couplings and fall away under the influence of an external force: in this case, gravity.

Constructing Minimum Connected Dominating Sets with Bounded Diameters in Wireless Networks

Abstract: Connected Dominating Sets (CDSs) can serve as virtual backbones for wireless networks A smaller virtual backbone incurs less maintenance overhead Unfortunately, computing a minimum size CDS is NP-hard, and thus most researchers in this area concentrate on how to construct smaller CDSs However, people neglected other important metrics of network, such as diameter and average hop distances between two communication parties In this paper, we investigate the problem of constructing quality CDS in terms of size, diameter, and Average Backbone Path Length (ABPL) We present two centralized algorithms having constant performance ratios for its size and diameter of the constructed CDS Especially, the size of CDS computed by the second algorithm is no more than 6906 times of its optimal solution Furthermore, we give its distributed version, which not only can be implemented in real situation easily but also considers energy to extend network lifetime In our simulation, we show that in average the distributed algorithm not only generates a CDS with smaller diameter and ABPL than related work but also suppresses its size well We also show that it is more energy efficient than others in prolonging network lifetime