Kiseok Kim, Sangmin Lee, Taehoon Yoo, Hwangnam Kim
In performing various missions using various types of vehicles or other moving objects, the positioning of each agent within the swarm is essential. In particular, for missions that require precise location estimation, the case of malicious attacks through data forgery cannot be excluded. In this paper, we propose a highly secure and accurate localization framework utilizing a Directed-Acyclic-Graph (DAG)-based distributed ledger as an intelligent vehicle network for an Ultra-Wideband (UWB) positioning system. When performing UWB positioning, the data generated from each node are used to calculate the Time of Flight (ToF), and if any of them are tampered with, the overall positioning performance is greatly reduced. We prevented positioning performance degradation by ensuring the safety and integrity of the data by applying a chain-based logical network between each node utilized for UWB positioning. The experimental results indicated that the proposed framework was effective at providing system stability and security without affecting the UWB positioning performance. In addition, the performance of the framework was verified by presenting defense indicators for various attack scenarios.
Ali Shakerian, Ali Eghmazi, Justin Goasdoué, René Landry
This paper proposes a novel Blockchain-based indoor navigation system that combines a foot-mounted dual-inertial measurement unit (IMU) setup and a zero-velocity update (ZUPT) algorithm for secure and accurate indoor navigation in GNSS-denied environments. The system estimates the user's position and orientation by fusing the data from two IMUs using an extended Kalman filter (EKF). The ZUPT algorithm is employed to detect and correct the error introduced by sensor drift during zero-velocity intervals, thus enhancing the accuracy of the position estimate. The proposed Low SWaP-C blockchain-based decentralized architecture ensures the security and trustworthiness of the system by providing an immutable and distributed ledger to store and verify the sensor data and navigation solutions. The proposed system is suitable for various indoor navigation applications, including autonomous vehicles, robots, and human tracking. The experimental results provide clear and compelling evidence of the effectiveness of the proposed system in ensuring the integrity, privacy, and security of navigation data through the utilization of blockchain technology. The system exhibits an impressive ability to process more than 680 transactions per second within the Hyperledger-Fabric framework. Furthermore, it demonstrates exceptional accuracy and robustness, with a mean RMSE error of 1.2 m and a peak RMSE of 3.2 during a 20 min test. By eliminating the reliance on external signals or infrastructure, the system offers an innovative, practical, and secure solution for indoor navigation in environments where GNSS signals are unavailable.
Mobile sign language apps have drawn a lot of interest recently as a way to minimize communication barriers between hearing people and people with hearing impairments. However, there are issues with the criteria and standards that should be taken into account when developing these apps. This study proposes a set of development criteria for sign language mobile apps and standardizes these criteria using the Fuzzy Delphi approach. Furthermore, the Fuzzy-Weighted Zero Inconsistency (FWZIC) approach is utilized to assign weights to the criteria and establish a ranking order. An initial set of requirements is developed based on the literature review. The Fuzzy Delphi technique is used, involving a panel of experts made up of developers, sign language experts, and users of sign language mobile apps, to assess the validity and reliability of the criteria. The FWZIC technique is used to give the criterion weights and determine their ranking order in order to further improve the decision-making process. The relative relevance of each criterion is determined by the FWZIC technique, which involves expert input and makes use of their knowledge and expertise. A thorough ranking is generated by taking into account the effects of each criterion on several zones, assisting in efficient decision-making during the creation of sign language mobile apps. Six Malaysian Sign Language apps that have been shortlisted are being utilized as a proof of concept to test the idea. The result of 6 apps is obtained based on the final standard criteria, their weights, and rankings.
Speech is a natural user interface for the Internet of Things system. However, the presence of noise affects severely the performance of such system. With the deployment of smart devices with microphones, one can form a powerful acoustic sensor network to enhance the speech via beamforming techniques. On the other hand, reliability of data transmission also determines the beamforming performance, since faulty data will drift the beamformer steering location randomly. Currently, there is no protection scheme for acoustic data transmitted over the wireless network in order to keep steady beamforming performance. In this article, we design a compound distributed beamformer, where nodes are grouped and the system is embedded with blockchain technology to protect the data integrity during transmission. It attempts to provide more possible reliable connections between groups. Simulated experiments show that the distributed beamformer with blockchain protection is able to maintain steady beamforming performance.