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1 – 10 of over 5000
Article
Publication date: 20 January 2012

Iftikhar H. Makhdoom and Qin Shi‐Yin

The purpose of this paper is to propose a new algorithm for in‐mission trajectories and speed adjustment of multiple unmanned aerial vehicles (UAVs) participating in a mission…

Abstract

Purpose

The purpose of this paper is to propose a new algorithm for in‐mission trajectories and speed adjustment of multiple unmanned aerial vehicles (UAVs) participating in a mission that requires them to arrive at target location simultaneously with switching and imperfect communication among the vehicles.

Design/methodology/approach

This algorithm, programmed at each UAV level, is based on the repeated consensus seeking among the participating vehicles about the time‐on‐target (ToT) through an imperfect inter‐vehicle communication link. The vehicles exchange their individual ToT values repeatedly for a particular duration to pick the highest value among all the vehicles in communication. A consensus confidence flag is set high when consensus is successful. After every consensus cycle with high confidence value, the mission adjustment is carried out by computing difference value between ToT consensus and a threshold value. For the difference values higher than a certain limit, vehicle's trajectory is adjusted by in‐mission insertion of new waypoint (WP) and for lower values the vehicle's speed is varied under allowable limits. The consensus seeking followed by the mission adjustment is repeated periodically to quash the imperfect communication effects.

Findings

A mathematical analysis has been carried out to establish the conditions for convergence of the algorithm. The simultaneous arrival of the vehicles subjected to switching communication is achieved only when the union of the switching links during the consensus period enables a vehicle to receive information from all the other vehicles and the switching rate is sufficiently high. This algorithm has been tested in a 6‐degree‐of‐freedom (DoF) multiple UAV simulation environment and achieves simultaneous arrival of multiple fixed wing UAVs under imperfect communication links that meets the aforementioned conditions.

Research limitations/implications

The presented algorithm and design strategy can be extended for other types of cooperative control missions where certain variable of interest is shared among all the vehicles over imperfect communication environment. The design is modular in functionality and can be incorporated into existing vehicles or simulations.

Originality/value

This research presents a new consensus algorithm that repeatedly performs polling of ToT among the vehicles through intermittent communication. The continual nature of consensus seeking covers the weakness of the imperfect communication. A two‐level mission adjustment provides better accuracy in simultaneous arrival at the target location.

Details

Aircraft Engineering and Aerospace Technology, vol. 84 no. 1
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 28 July 2022

Michel Toulouse, H.K. Dai and Truong Giang Le

Sharding of blockchains consists of partitioning a blockchain network into several sub-networks called “shards,” each shard processing and storing disjoint sets of transactions in…

Abstract

Purpose

Sharding of blockchains consists of partitioning a blockchain network into several sub-networks called “shards,” each shard processing and storing disjoint sets of transactions in parallel. Sharding has recently been applied to public blockchains to improve scalability through parallelism. The throughput of sharded blockchain is optimized when the workload among the shards is approximately the same. The purpose of this paper is to investigate the problem of balancing workload of account-based blockchains such as Ethereum.

Design/methodology/approach

Two known consensus-based distributed load-balancing algorithms have been adapted to sharded blockchains. These algorithms migrate accounts across shards to balance transaction processing times. Two methods to predict transaction processing times are proposed.

Findings

The authors identify some challenging aspects for solving the load-balancing problem in sharded blockchains. Experiments conducted with Ethereum transactions show that the two load-balancing algorithms are challenged by accounts often created to process a single transaction to optimize anonymity, while existing accounts sparsely generate transactions.

Originality/value

Tests in this work have been conducted on transactions originating from a blockchain platform rather than using artificially generated data distributions. They show the specificity of the load-balancing problem for sharded blockchains, which were hidden in artificial data sets.

Details

International Journal of Web Information Systems, vol. 18 no. 2/3
Type: Research Article
ISSN: 1744-0084

Keywords

Article
Publication date: 27 September 2022

Mingyue Xie, Jun Liu, Shuyu Chen and Mingwei Lin

As the core technology of blockchain, various consensus mechanisms have emerged to satisfy the demands of different application scenarios. Since determining the security…

Abstract

Purpose

As the core technology of blockchain, various consensus mechanisms have emerged to satisfy the demands of different application scenarios. Since determining the security, scalability and other related performance of the blockchain, how to reach consensus efficiently of consensus mechanism is a critical issue in the blockchain.

Design/methodology/approach

The paper opted for a research overview on the blockchain consensus mechanism, including the consensus mechanisms' consensus progress, classification and comparison, which are complemented by documentary analysis.

Findings

This survey analyzes solutions for the improvement of consensus mechanisms in blockchain that have been proposed during the last few years and suggests future research directions around consensus mechanisms. First, the authors outline the consensus processes, the advantages and disadvantages of the mainstream consensus mechanisms. Additionally, the consensus mechanisms are subdivided into four types according to their characteristics. Then, the consensus mechanisms are compared and analyzed based on four evaluation criteria. Finally, the authors summarize the representative progress of consensus mechanisms and provide some suggestions on the design of consensus mechanisms to make further advances in this field.

Originality/value

This paper summarizes the future research development of the consensus mechanisms.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 16 no. 2
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 17 October 2018

Weinan Wu, Naigang Cui, Wenzhao Shan and Xiaogang Wang

The purpose of this paper is to develop a distributed task allocation method for cooperative mission planning of multiple heterogeneous unmanned aerial vehicles (UAVs) based on…

Abstract

Purpose

The purpose of this paper is to develop a distributed task allocation method for cooperative mission planning of multiple heterogeneous unmanned aerial vehicles (UAVs) based on the consensus algorithm and the online cooperative strategy.

Design/methodology/approach

In this paper, the allocation process is conducted in a distributed framework. The cooperative task allocation problem is proposed with constraints and uncertainties in a real mission. The algorithm based on the consensus algorithm and the online cooperative strategy is proposed for this problem. The local chain communication mode is adopted to restrict the bandwidth of the communication link among the UAVs, and two simulation tests are given to test the optimality and rapidity of the proposed algorithm.

Findings

This method can handle both continuous and discrete uncertainties in the mission space, and the proposed algorithm can obtain a feasible solution in allowable time.

Research limitations/implications

This study is only applied to the case that the total number of the UAVs is less than 15.

Practical implications

This study is expected to be practical for a real mission with uncertain targets.

Originality/value

The proposed algorithm can go beyond previous works that only deal with continuous uncertainties, and the Bayesian theorem is adopted for estimation of the target.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 9
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 22 August 2022

Mabrook Al-Rakhami and Majed Al-Mashari

This work focuses on the interoperability of the blockchain from the viewpoint of its technological evolution in the wider context of supply chain systems. Interoperability…

Abstract

Purpose

This work focuses on the interoperability of the blockchain from the viewpoint of its technological evolution in the wider context of supply chain systems. Interoperability concerns the most since it is among the most persevering problems in the process of blockchain adaptation. The study aims to trace and pinpoint all the different methods that affect the interoperability of blockchains, gather all the obtainable evidence and recognize gaps in between the applicable approaches mentioned across the contemporary academic literature.

Design/methodology/approach

An analysis is done of seven interoperability approaches based on their relevance, practical usefulness and adoption processes concerning the blockchain. Mainly, this work examines interoperability from several different perspectives. An interoperability modular decomposition via a layered model has been defined through the level of conceptual interoperability (LCIM) and level of information system interoperability (LISI), which represent the most popular metrics with regard to assessing the level of interoperability from a qualitative level.

Findings

Generally, the findings of this work are directed in two major aspects: Firstly, it expands the research around blockchain technology interoperability by providing crucial background information and pinpointing important connotations for both industrial and academic environments. It also defines and analyzes several different approaches toward the blockchain platform's interoperability. Secondly, it also identifies and proposes several scenarios that take advantage of multiple blockchain application approaches, highlights various issues and challenges to the evolution of interoperability standards and solutions and indicates the desired areas of further research.

Originality/value

An essential aspect of the originality of this paper is that, contrary to other work contributions, this work summarized the different interoperability approaches for blockchain in supply chain systems. Mainly, seven approaches were discussed for practitioners and researchers, and the open issues and future research direction were considered.

Details

Business Process Management Journal, vol. 28 no. 5/6
Type: Research Article
ISSN: 1463-7154

Keywords

Article
Publication date: 17 April 2019

Hu Xiao, Rongxin Cui and Demin Xu

This paper aims to present a distributed Bayesian approach with connectivity maintenance to manage a multi-agent network search for a target on a two-dimensional plane.

Abstract

Purpose

This paper aims to present a distributed Bayesian approach with connectivity maintenance to manage a multi-agent network search for a target on a two-dimensional plane.

Design/methodology/approach

The Bayesian framework is used to compute the local probability density functions (PDFs) of the target and obtain the global PDF with the consensus algorithm. An inverse power iteration algorithm is introduced to estimate the algebraic connectivity λ2 of the network. Based on the estimated λ2, the authors design a potential field for the connectivity maintenance. Then, based on the detection probability function, the authors design a potential field for the search target. The authors combine the two potential fields and design a distributed gradient-based control for the agents.

Findings

The inverse power iteration algorithm can distributed estimate the algebraic connectivity by the agents. The agents can efficient search the target with connectivity maintenance with the designed distributed gradient-based search algorithm.

Originality/value

Previous study has paid little attention to the multi-agent search problem with connectivity maintenance. Our algorithm guarantees that the strongly connected graph of the multi-agent communication topology is always established while performing the distributed target search problem.

Details

Assembly Automation, vol. 40 no. 1
Type: Research Article
ISSN: 0144-5154

Keywords

Content available
Book part
Publication date: 9 March 2021

Abstract

Details

The Emerald Handbook of Blockchain for Business
Type: Book
ISBN: 978-1-83982-198-1

Article
Publication date: 23 October 2020

Xiaofang Xue, Junpeng Dou and Yao Shang

Information sharing helps improve the efficiency of the supply chain. However, there are some problems in the multi-stage structure supply chain, such as untimely information…

2505

Abstract

Purpose

Information sharing helps improve the efficiency of the supply chain. However, there are some problems in the multi-stage structure supply chain, such as untimely information feedback and distortion. Despite recent progress in ensuring improved collaboration in the past decade or so, the inefficiency status continues to persist. It is also difficult to add value to the supply chain. The information sharing framework and decentralized model designed in this paper are to deal with existing problems.

Design/methodology/approach

This paper is based on the theoretical research of supply chain information asymmetry and synergetics. We attempt to introduce blockchain technology into supply chain operation management, reconstruct information sharing architecture and provide a new decentralized mode to promote the collaborative operation of all nodes. The information sharing and decentralization operational model are built, which has changed the hierarchical relationship between upstream and downstream enterprises, regarding customers as the center of the whole system and effectively reducing the bullwhip effect. Finally, we selected the home supply chain as an example design and performed system dynamics simulation on the blockchain-based operation process.

Findings

The model of setting up the scene application mode based on blockchain is helpful to realize the goal of supply chain management to reduce cost, improve quality and enhance the overall efficiency of the system.

Originality/value

Based on the blockchain technology, this paper constructed a new supply chain operation mode and used the synergetic theory and the concept of the product–service system to explain the process of value increment in detail.

Details

Business Process Management Journal, vol. 27 no. 1
Type: Research Article
ISSN: 1463-7154

Keywords

Article
Publication date: 14 March 2022

Anup Kumar, Santosh Kumar Srivastava and Sarbjit Singh

This study aims to formulate a conceptual sustainable framework for developing a trusted, reliable, scalable, transparent, traceable and sustainable agri-food supply chain in a…

1282

Abstract

Purpose

This study aims to formulate a conceptual sustainable framework for developing a trusted, reliable, scalable, transparent, traceable and sustainable agri-food supply chain in a developing country so that it minimizes wastage and increases the efficiency levels of agri-produce and its usage.

Design/methodology/approach

This study uses a rigorous review of extant literature, case studies and the interview method for theory building, using blockchain technology (BT) as a subject. Further, the study builds a framework to relate blockchain solutions to the challenges faced by the agri-supply chain. Notably, the use of BT in the agri-food supply chain is a relatively new area of study.

Findings

Limitations of using BT 3.0 in a diverse supply chain like the food sector, especially in a developing country such as India, may be overcome by adopting BT 4.0 and could change the country’s face by controlling inefficiencies and ensuring transparency, helping in good governance, improving the humanitarian supply chain and integrating the bottom of the pyramid to the main economy. Based on the findings, this study proposes BT 4.0 for the agri-supply chain in India to deal with the current issues of demand-supply gap, wastages of agri-produce, unequal distribution of profit among agriproduct producers and logistics suppliers and ensuring sustainability.

Research limitations/implications

Results in this study have been derived from a specific demographic condition in India. Future research with other demographic conditions may be replicated. BT is a new technology product, and its effectiveness is yet to be established.

Practical implications

The outcome of this study provides the application of BT 4.0 in the area of the agri-food supply chain. The BT 4.0 framework has been developed on studying a few cases that either implemented BT or were in the testing phase. The benefits of the agri-food supply chain vis-à-vis its overall social well-being may be achieved on the successful implementation of the framework, despite existing complexities in the food supply chain. Further research on this subject may help the other dimensions of the complexity of adopting BT 4.0. Both practitioners and policymakers from developing countries can, therefore, use the findings of this study to analyze BT 4.0 and address the concerns of the agri-food supply chain.

Originality/value

This research paper has proposed a conceptual framework of BT 4.0, which is a completely new technology. It is fairly transparent, and therefore sustainable supply chain practices may be achieved easily.

Details

Journal of Global Operations and Strategic Sourcing, vol. 15 no. 3
Type: Research Article
ISSN: 2398-5364

Keywords

Article
Publication date: 20 June 2023

Yukun Hu, Suihuai Yu, Dengkai Chen, Jianjie Chu, Yanpu Yang and Qing Ao

A successful process of design concept evaluation has positive influence on subsequent processes. This study aims to consider the evaluation information at multiple stages and the…

Abstract

Purpose

A successful process of design concept evaluation has positive influence on subsequent processes. This study aims to consider the evaluation information at multiple stages and the interaction among evaluators and improve the credibility of evaluation results.

Design/methodology/approach

This paper proposes a multi-stage approach for design concept evaluation based on complex network and bounded confidence. First, a network is constructed according to the evaluation data. Depending on the consensus degree of evaluation opinions, the number of evaluation rounds is determined. Then, bounded confidence rules are applied for the modification of preference information. Last, a planning function is constructed to calculate the weight of each stage and aggregate information at multiple evaluation stages.

Findings

The results indicate that the opinions of the evaluators tend to be consistent after multiple stages of interactive adjustment, and the ordering of design concept alternatives tends to be stable with the progress of the evaluation.

Research limitations/implications

Updating preferences according to the bounded confidence rules, only the opinions within the trust threshold are considered. The attribute information of the node itself is inadequately considered.

Originality/value

This method addresses the need for considering the evaluation information at each stage and minimizes the impact of disagreements within the evaluation group on the evaluation results.

Details

Kybernetes, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0368-492X

Keywords

1 – 10 of over 5000