The fusion of hyperspectral and light detection and range (LiDAR) data has been an active research topic. Existing fusion methods have ignored the high-dimensionality and redundancy challenges in hyperspectral images (HSIs), despite that band selection methods have been intensively studied for HSI processing. This article addresses this significant gap by introducing a cross-attention mechanism from the transformer architecture for the selection of HSI bands guided by LiDAR data. LiDAR provides high-resolution vertical structural information, which can be useful in distinguishing different types of land cover that may have similar spectral signatures but different structural profiles. In our approach, the LiDAR data are used as the “query” to search and identify the “key” from the HSI to choose the most pertinent bands for LiDAR. This method ensures that the selected HSI bands drastically reduce redundancy and computational requirements while working optimally with the LiDAR data. Extensive experiments have been undertaken on three paired HSI and LiDAR datasets: Houston 2013, Trento, and MUUFL. The results highlight the superiority of the cross-attention mechanism, underlining the enhanced classification accuracy of the identified HSI bands when fused with the LiDAR features. The results also show that the use of fewer bands combined with LiDAR surpasses the performance of state-of-the-art fusion models.

Workflow tasks are time-sensitive and their task completion utility, i.e., value of task completion, is inversely proportional to their completion time. Existing solutions to the NP-hard problem of utility-maximization task scheduling were achieved under the assumptions of linear Time Utility Function (TUF), i.e., utility is inversely proportional to completion time following a linear function, and prior knowledge of task execution time, which is unrealistic for many applications and dynamic systems. This paper proposes a novel model of combining greedy optimization with machine learning for scheduling time-sensitive tasks with convex TUF and unknown task execution time on heterogeneous cloud servers offline nonpreemptively to maximize the total utility of input tasks. For a set of time-sensitive tasks with data dependencies, we first employ multi-layer perceptron neural networks to predict task execution time by utilizing historical data. Then, by solving a linear program after relaxing the disjunctive constraint introduced by the nonpreemption requirement to calculate maximum utility increment, we propose a novel greedy algorithm of marginal incremental utility maximization that jointly determines the task-to-processor allocation plan and tasks' execution sequence on each processor. We then show that our algorithm has an expected approximation ratio of $\frac{(e-1)(\tau -2)}{e\tau }$ for convex TUF and $\frac{e-1}{3e}\approx 0.21$ for linear TUF, where $\tau$ is the ratio of total completion utility over total delay cost under optimal scheduling. Our result presents the first polynomial-time approximation solution for this problem that achieves a performance guarantee of bounded ratio for convex TUF and constant ratio for linear TUF respectively. Extensive experiment results through both simulation and real cloud implementation demonstrate significant performance improvement of our algorithm over the known results.

Unmanned aerial vehicles (UAVs) have emerged as crucial components in advancing mobile edge computing (MEC), leveraging their proximity to edge nodes and scalable nature. This synergy holds significant promise within the Internet of Things (IoT) and Beyond 5G (B5G) domains. In this article, we concentrate on optimizing the shrinking ratio, a Quality of Experience (QoE) metric, within large-scale IoT networks empowered by UAV-enhanced MEC via joint optimizing task offloading, resource allocation, and UAV trajectories. This joint optimization problem presents significant challenges due to the intertwined nature of multiuser computing mode selection and strong coupling between user equipments (UEs) waiting time and UAV trajectory. To tackle these challenges, we formulate the problem as a mixed integer nonlinear programming (MINLP) problem and propose an iterative algorithm named BTOU by decomposing the original problem into two subproblems using the block coordinate descent (BCD) framework. For the task offloading and resource allocation subproblem, we present two algorithms: one employs a low-complexity greedy game-theoretic approach suitable for a large number of UEs, while the other leverages the penalty successive convex approximation (PSCA) technique along with first-order Taylor expansion approximation to achieve high-solution quality. For the UAV trajectory planning subproblem, we transform it into a Miller-Tucker–Zemlin (MTZ) model and devise a solution strategy. Extensive simulation results validate the effectiveness of our proposed algorithm, showcasing rapid convergence and a notable improvement in QoE of over 10% compared to benchmark methods.

Mobile edge computing (MEC) integrated with wireless power transfer (WPT) has became a promising trend to shorten task delay and prolong battery life of wireless devices (WDs). Introducing the relay technique to WPT-MEC system can improve offloading capability and energy efficiency, particularly in the scenarios of poor wireless channel conditions between the server and WDs. In this paper, we focus on maximizing the energy efficiency (EE) of a multi-user relay-aided WPT-MEC system. The joint optimization of the configuration of relay, wireless charge time fraction, and decision of WDs’ offloading strategy presents significant challenges due to the combination of multi-user computing mode selection and strong coupling of transmission time allocation for each WD. To address these challenges, we formulate the problem as a mixed integer nonlinear programming (MINLP) problem and propose an efficient iterative algorithm called MSRA to solve it. Our approach leverages Dinkelbach’s method to transform the original problem into a tractable problem. Furthermore, we employ the alternating direction method of multipliers (ADMM) technique to decompose the problem into multiple subproblems, thereby avoiding the combination of computing mode selection at each WD and hence enabling parallel computation. Within each iteration step of the ADMM-based algorithm, we develop a DAI-Based algorithm to handle the strong coupling with offloading time allocation that incorporates a Bisection Search algorithm with constant time complexity and solves a standard convex problem. Extensive simulation results demonstrate the effectiveness of our proposed algorithm as evidenced by its rapid convergence and impressive energy efficiency imporvement of over 15% compared to benchmark methods.

Publication of trajectory data that contain rich information of vehicles in the dimensions of time and space (location) enables online monitoring and supervision of vehicles in motion and offline traffic analysis for various management tasks. However, it also provides security holes for privacy breaches as exposing individual’s privacy information to public may results in attacks threatening individual’s safety. Therefore, increased attention has been made recently on the privacy protection of trajectory data publishing. However, existing methods, such as generalization via anonymization and suppression via randomization, achieve protection by modifying the original trajectory to form a publishable trajectory, which results in significant data distortion and hence a low data utility. In this work, we propose a trajectory privacy-preserving method called dynamic anonymization with bounded distortion. In our method, individual trajectories in the original trajectory set are mixed in a localized manner to form synthetic trajectory data set with a bounded distortion for publishing, which can protect the privacy of location information associated with individuals in the trajectory data set and ensure a guaranteed utility of the published data both individually and collectively. Through experiments conducted on real trajectory data of Guangzhou City Taxi statistics, we evaluate the performance of our proposed method and compare it with the existing mainstream methods in terms of privacy preservation against attacks and trajectory data utilization. The results show that our proposed method achieves better performance on data utilization than the existing methods using globally static anonymization, without trading off the data security against attacks.