Recent studies have shown that posterior communicating artery (PComA) aneurysms are more likely to rupture. However, surgical intervention for PComA aneurysms may be associated with increased treatment-related morbidity rate. Therefore, it is meaningful to investigate the factors related to PComA aneurysm rupture. The purpose of this study was to identify morphological parameters that significantly correlate with PComA aneurysm rupture. We divided 14 pairs of mirror posterior communicating artery aneurysms (PComA-MANs) into ruptured and unruptured groups. Computed tomography angiography (CTA) imaging was evaluated with three-dimensional (3D) Slicer to generate models of the aneurysms and surrounding vasculature. Nine morphological parameters [size, height, width, neck width, aspect ratio (AR), bottleneck factor (BNF), height/width ratio (H/W), size ratio (SR), and bleb formation] were examined in the two groups for significance with respect to rupture. By contrast, statistically significant differences were found in ruptured and unruptured group for size, AR, BNF, SR, and bleb formation (P < 0.05). Parameters that had no significant differences between the two groups were height (P = 0.103), width (P = 0.078), neck width (P = 0.808), and H/W (P = 0.417). We conclude that MANs may be a useful model for the morphological analysis of intracranial aneurysm rupture. Larger size, higher AR, BNF, SR, and bleb formation may be related to rupture of PComA aneurysms. Larger sample studies minimizing the interference from patient-related factors and aneurysm type were expected for acquiring more accurate assessment of the relationship between these parameters and PComA aneurysm rupture.

The fifth generation (5G) of mobile radio technologies has been defined as a new delivery model where services are tailored to specific vertical industries. 5G supports three types of services with different and heterogeneous requirements, i.e. enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC) and massive Machine-Type Communications (mMTC). These services are directly related to exemplary verticals such as media, vehicular communications or the Industry 4.0. This work provides a detailed analysis and performance evaluation of 5G New Radio (NR) against a set of Key Performance Indicators (KPI), as defined in the International Mobile Telecommunications 2020 (IMT-2020) guidelines, and provides an overview about the fulfillment of their associated requirements. The objective of this work is to provide an independent evaluation, complementing the Third Generation Partnership Project (3GPP) contribution. From the original group of sixteen KPIs, eleven of them have been carefully selected to cover the three usage scenarios, paying special attention to eMBB services. Results show that 5G NR achieves all considered requirements, therefore fulfilling the specific market's needs for years to come.

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Cellular networks assisted by flexibly placed high-maneuverability unmanned aerial vehicles (UAVs) have attracted virtual interests recently. In this paper, the utility maximization problem is investigated to determine how to improve the performance of multi-UAV enabled software-defined cellular networks (SDCNs) with wireless backhaul. The formulated problem jointly optimizes the three dimensional (3D) UAV placement, user scheduling and association, and spectrum resource allocation. The proposed problem is intractable since it is a mixed-integer combined non-convex problem. Thus, an efficient distributed alternating maximization (AM) iterative algorithm is developed to solve the proposed problem. Then, the original optimization problem is decomposed into three subproblems that are solved alternatively via the successive convex optimization (SCO) technique and the modified alternating direction method of multipliers (ADMM) in the proposed algorithm. The theoretical analysis and the simulation results confirm the convergence performance of the proposed algorithm. The extensive numerical results substantiate the superiority of the proposed algorithm, which significantly increases the throughput and utility of the overall users relative to the traditional overlaid ground base station (GBS) and UAV structure and other benchmark methods. The maximal throughput gain is as large as 74.9% on average for all users, in contrast to other benchmark schemes.INDEX TERMS 3D UAV placement, alternating direction method of multipliers, alternating maximization, resource allocation, software-defined network, software-defined cellular network, successive convex optimization, user association.