Various applications have utilized a mobile mapping system (MMS) as the main 3D urban remote sensing platform. However, the accuracy and precision of the three-dimensional data acquired by an MMS is highly dependent on the performance of the vehicle’s self-localization, which is generally performed by high-end global navigation satellite system (GNSS)/inertial measurement unit (IMU) integration. However, GNSS/IMU positioning quality degrades significantly in dense urban areas with high-rise buildings, which block and reflect the satellite signals. Traditional landmark updating methods, which improve MMS accuracy by measuring ground control points (GCPs) and manually identifying those points in the data, are both labor-intensive and time-consuming. In this paper, we propose a novel and comprehensive framework for automatically georeferencing MMS data by capitalizing on road features extracted from high-resolution aerial surveillance data. The proposed framework has three key steps: (1) extracting road features from the MMS and aerial data; (2) obtaining Gaussian mixture models from the extracted aerial road features; and (3) performing registration of the MMS data to the aerial map using a dynamic sliding window and the normal distribution transform (NDT). The accuracy of the proposed framework is verified using field data, demonstrating that it is a reliable solution for high-precision urban mapping.

This paper explores the potential for communication-efficient federated learning (FL) in modern distributed systems. FL is an emerging distributed machine learning technique that allows for the distributed training of a single machine learning model across multiple geographically distributed clients. This paper surveys the various approaches to communication-efficient FL, including model updates, compression techniques, resource management for the edge and cloud, and client selection. We also review the various optimization techniques associated with communication-efficient FL, such as compression schemes and structured updates. Finally, we highlight the current research challenges and discuss the potential future directions for communication-efficient FL.

Big data is a rapidly growing field, and new developments are constantly emerging to address various challenges. One such development is the use of federated learning for recommendation systems (FRSs). An FRS provides a way to protect user privacy by training recommendation models using intermediate parameters instead of real user data. This approach allows for cooperation between data platforms while still complying with privacy regulations. In this paper, we explored the current state of research on FRSs, highlighting existing research issues and possible solutions. Specifically, we looked at how FRSs can be used to protect user privacy while still allowing organizations to benefit from the data they share. Additionally, we examined potential applications of FRSs in the context of big data, exploring how these systems can be used to facilitate secure data sharing and collaboration. Finally, we discuss the challenges associated with developing and deploying FRSs in the real world and how these challenges can be addressed.

Recently, autonomous vehicle's self-localization based on the matching of laser scanner data to the high definition (HD) map become more popular due to the availability of HD map and price down of light detection and ranging technologies. Many types of research have been done to achieve locally and globally accurate HD map for accurate localization. However, the global accuracy of the map does not guarantee accurate self-localization within the map. To achieve accurate self-localization, the map should satisfy some requirements. In this paper, the focus is made on the map, as one of the high potential sources of error in localization. By investigating the erroneous scenarios in the map and comparing their characteristics, we introduced four criteria for the self-localization ability of the map. These criteria are feature sufficiency, layout, local similarity, and representation quality of the map. Then, in order to quantify these criteria, we introduce several factors for each criterion. Unlike evaluation criteria which are defined regardless of the map formats, factors are defined based on normal distribution map which is a map format of normal distribution transformation scan-matching. These factors are calculated for each position in the map, based on the map features within its local vicinity. By conducting the experiments in Shinjuku, Japan, we have evaluated these factors in a different part of the map with different scenarios by comparing them with the self-localization error.

The rapid increase in the number of connected vehicles on roads has made vehicular ad-hoc networks (VANETs) an attractive target for malicious actors. As a result, VANETs require secure data transmission to maintain the network’s integrity. Federated learning (FL) has been proposed as a secure data-sharing method for VANETs, but it is limited in its ability to protect sensitive data. This article proposes integrating Blockchain technology into FL to provide an additional layer of security for VANETs. In particular, we propose a secure and efficient blockchain-based FL (SEBFL) approach to ensure communication efficiency and data privacy in VANETs. To this end, we use the FL model for VANETs, where computation tasks are decomposed from a base station to individual vehicles. This effectively reduces the congestion delay and communication overhead. Integrating blockchain with the FL model provides a reliable and secure data communication system between vehicles, roadside units, and a cloud server. Additionally, we use a homomorphic encryption system (HES) that effectively preserves the confidentiality and credibility of vehicles. Besides, the proposed SEBFL leverages the asynchronous FL model, minimizing the long delay while avoiding possible threats and attacks using HES. The experimental results show that the proposed SEBFL achieves 0.87% accuracy while a model inversion attack and 0.86% accuracy while a membership inference attack.

Map-matching based on light detection and ranging (LiDAR) is a promising method for accurate self-localization and recently has gained a wider focus due to the availability of high definition (HD) maps and price-down of LiDARs. In this method, the input scan of the LiDAR is matched to the prebuilt map to get a centimeter-level accuracy position of the vehicle. However, in some places of the map, due to the lack of features, the presence of the repetitive features, the layout of the features, and other factors, the map-matching error might exceed the required bound for autonomous driving. In our previous work, four criteria for evaluation of the features of the map was introduced and it is shown that by examining the corresponding factors for each criterion, the map-matching error can be modeled. In this work, one of the map criteria called local similarity is further investigated and in order to quantify the fulfillment of this criterion, three new factors, namely pfh_similarity , pfh_entropy , and battacharya_similarity are introduced. In addition to this, a framework for pre-estimation of the map-matching error considering these four criteria based on random forest regression is proposed. To evaluate the accuracy of the framework, experiments were conducted for 3.6 km in Shinjuku, Tokyo. Experimental results show that using the proposed framework, in 64.1% of the cases, the localization error can be estimated with less than 2.5cm of the estimation error.