@article{reza_rahmati_wu_dai_2023, title={CGBA: Curvature-aware Geometric Black-box Attack}, ISSN={["1550-5499"]}, DOI={10.1109/ICCV51070.2023.00018}, abstractNote={Decision-based black-box attacks often necessitate a large number of queries to craft an adversarial example. Moreover, decision-based attacks based on querying boundary points in the estimated normal vector direction often suffer from inefficiency and convergence issues. In this paper, we propose a novel query-efficient curvature-aware geometric decision-based black-box attack (CGBA) that conducts boundary search along a semicircular path on a restricted 2D plane to ensure finding a boundary point successfully irrespective of the boundary curvature. While the proposed CGBA attack can work effectively for an arbitrary decision boundary, it is particularly efficient in exploiting the low curvature to craft high-quality adversarial examples, which is widely seen and experimentally verified in commonly used classifiers under non-targeted attacks. In contrast, the decision boundaries often exhibit higher curvature under targeted attacks. Thus, we develop a new query-efficient variant, CGBA-H, that is adapted for the targeted attack. In addition, we further design an algorithm to obtain a better initial boundary point at the expense of some extra queries, which considerably enhances the performance of the targeted attack. Extensive experiments are conducted to evaluate the performance of our proposed methods against some well-known classifiers on the ImageNet and CIFAR10 datasets, demonstrating the superiority of CGBA and CGBA-H over state-of-the-art non-targeted and targeted attacks, respectively. The source code is available at https://github.com/Farhamdur/CGBA.}, journal={2023 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION, ICCV}, author={Reza, Md Farhamdur and Rahmati, Ali and Wu, Tianfu and Dai, Huaiyu}, year={2023}, pages={124–133} }
 @article{hosseinalipour_rahmati_eun_dai_2021, title={Energy-Aware Stochastic UAV-Assisted Surveillance}, volume={20}, ISSN={["1558-2248"]}, DOI={10.1109/TWC.2020.3044490}, abstractNote={With the ease of deployment, capabilities of evading the jammers and obscuring their existence, unmanned aerial vehicles (UAVs) are one of the most suitable candidates to perform surveillance. There exists a body of literature in which the inspectors follow a deterministic trajectory to conduct surveillance, which results in a predictable environment for malicious entities. Thus, introducing randomness to the surveillance is of particular interest. In this work, we propose a novel framework for stochastic UAV-assisted surveillance that i) inherently considers the battery constraints of the UAVs, ii) proposes random moving patterns modeled via random walks, and iii) adds another degree of randomness to the system via considering probabilistic inspections. We formulate the problem of interest, i.e., obtaining the energy-efficient random walk and inspection policies of the UAVs subject to probabilistic constraints on inspection criteria of the sites and battery consumption of the UAVs, which turns out to be signomial programming that is highly non-convex. To solve it, we propose a centralized and a distributed algorithm along with their performance guarantee. This work contributes to both UAV-assisted surveillance and classic random walk literature by designing random walks with random inspection policies on weighted graphs with energy limited random walkers.}, number={5}, journal={IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS}, author={Hosseinalipour, Seyyedali and Rahmati, Ali and Eun, Do Young and Dai, Huaiyu}, year={2021}, month={May}, pages={2820–2837} }
 @article{bhuyan_guvenc_dai_sichitiu_singh_rahmati_maeng_2021, title={Secure 5G Network for a Nationwide Drone Corridor}, ISSN={["1095-323X"]}, DOI={10.1109/AERO50100.2021.9438162}, abstractNote={5G can provide the multiplicative capacity gains needed to support a large number of drones/UAS (Unmanned Aircraft Systems). 5G cellular networks with newly available millimeter wave (mmWave) frequency bands can provide wireless communication links for control as well as data traffic for drones and drone swarms. Drones are becoming increasingly important for commercial uses such as delivery and transportation as well as for public safety search and rescue of natural disaster victims, surveillance of remote critical infrastructure, surveys of environmental quality in protected regions, and detection of threats during major public events. This paper presents research findings in the following areas critical to validating the effectiveness of providing required 5G access to the drones with security, reliability, and spectral efficiency: 1) Radio coverage for the drone corridor by adding a separate set of antennas for coverage in the air while the conventional set of antennas continues to provide coverage on the ground. Beam transmission and validation with ray-tracing simulations are covered. 2) Optimization of uplink communication from a swarm of drones with a single mmWave beam by grouping the drones with power allocations for non-orthogonal multiple access (NOMA). 3) Optimization of the network lifetime of a swarm of drones resulting in suitable trajectories in the presence of interference. 4) Methods including precoding that can enhance physical layer security with channel information about the interference source. The paper concludes with plans for future research to provide further scientific basis for the proposed cellular drone network.}, journal={2021 IEEE AEROSPACE CONFERENCE (AEROCONF 2021)}, author={Bhuyan, Arupjyoti and Guvenc, Ismail and Dai, Huaiyu and Sichitiu, Mihail L. and Singh, Simran and Rahmati, Ali and Maeng, Sung Joon}, year={2021} }
 @article{rahmati_hosseinalipour_yapici_guvenc_dai_bhuyan_2020, title={Energy-Efficient Beamforming and Power Control for Uplink NOMA in mmWave UAV Networks}, ISSN={["2576-6813"]}, DOI={10.1109/GLOBECOM42002.2020.9348114}, abstractNote={The integration of unmanned aerial vehicles (UAVs) into the terrestrial communications networks with a variety of tasks is viewed as a key technology for 5G and beyond. In this work, we consider the uplink millimeter-wave (mmWave) transmission between a set of UAVs and a base station (BS), where the UAVs deploy uplink non-orthogonal multiple access (NOMA) in multiple clusters. Furthermore, the BS also serves its own desired ground user equipment (UE) in the presence of many other ground UEs associated with other cells, which share the same frequency band. Considering the limited energy budget of UAVs, we formulate an energy efficiency (EE) problem, and propose a solution aided by the Dinkelbach's algorithm and successive convex approximation (SCA). Using realistic air-to-ground (A2G) and terrestrial channel models, we assess the performance of the proposed algorithm under various circumstances (maximum transmit power for UAVs, quality-of-service (QoS) constraint for the desired UE, etc.), and identify the best use cases.}, journal={2020 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM)}, author={Rahmati, Ali and Hosseinalipour, Seyyedali and Yapici, Yavuz and Guvenc, Ismail and Dai, Huaiyu and Bhuyan, Arupjyoti}, year={2020} }
 @article{parvez_rahmati_guvenc_sarwat_dai_2018, title={A Survey on Low Latency Towards 5G: RAN, Core Network and Caching Solutions}, volume={20}, ISSN={["1553-877X"]}, url={https://doi.org/10.1109/COMST.2018.2841349}, DOI={10.1109/COMST.2018.2841349}, abstractNote={The fifth generation (5G) wireless network technology is to be standardized by 2020, where main goals are to improve capacity, reliability, and energy efficiency, while reducing latency and massively increasing connection density. An integral part of 5G is the capability to transmit touch perception type real-time communication empowered by applicable robotics and haptics equipment at the network edge. In this regard, we need drastic changes in network architecture including core and radio access network (RAN) for achieving end-to-end latency on the order of 1 ms. In this paper, we present a detailed survey on the emerging technologies to achieve low latency communications considering three different solution domains: 1) RAN; 2) core network; and 3) caching. We also present a general overview of major 5G cellular network elements such as software defined network, network function virtualization, caching, and mobile edge computing capable of meeting latency and other 5G requirements.}, number={4}, journal={IEEE COMMUNICATIONS SURVEYS AND TUTORIALS}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Parvez, Imtiaz and Rahmati, Ali and Guvenc, Ismail and Sarwat, Arif I. and Dai, Huaiyu}, year={2018}, pages={3098–3130} }