Autonomous air drones, known as unmanned aerial vehicles (UAVs), often accomplish missions with real-time video streaming leveraging the available cellular network. Video streaming is a typical ...application with stringent quality of service (QoS) requirements, which are not always supported in the whole mission area. In this paper, we address the offline path planning problem of finding the optimal path from a source to a destination in 2-D space in order to maximize the communication quality, given a cellular coverage, and thus providing throughput guarantees to the video streaming. In addressing the problem, the restricted amount of available energy, the wind effect, and the path post-smoothing problem are considered. We propose two innovative path planning algorithms and we show that our algorithms outperform classical approaches that are oblivious of communication network coverage. Both algorithms are variants of classical A* algorithm and they optimize the path jointly in terms of distance and of the experienced throughput by the drone: in this way, the quality of the video streaming along the path is optimized while preserving the energy budget for the flight. We describe both of the algorithms and investigate their performance. Moreover, we introduce a novel path smoothing method that outperforms classing approaches in terms of distance and computation cost. Finally, in order to prove that our algorithms can be practically utilized in the real-world path planners, we integrate our proposed path planning algorithms into the popular QGroundControl (QGC) control station.
Wearable devices have become essential in our daily activities. Due to battery constraints, the use of computing, communication, and storage resources is limited. Mobile cloud computing (MCC) and the ...recently emerged fog computing (FC) paradigms unleash unprecedented opportunities to augment the capabilities of wearable devices. Partitioning mobile applications and offloading computationally heavy tasks for execution to the cloud or edge of the network is the key. Offloading prolongs the lifetime of the batteries and allows wearable devices to gain access to the rich and powerful set of computing and storage resources of the cloud/edge. In this paper, we experimentally evaluate and discuss the rationale of application partitioning for MCC and FC. To experiment, we develop an Android-based application and benchmark energy and execution time performance of multiple partitioning scenarios. The results unveil architectural tradeoffs that exist between the paradigms and devise guidelines for proper power management of the service-centric Internet-of-Things applications.
Online gaming has seen a significant surge in popularity, becoming a dominant form of entertainment worldwide. This growth has necessitated the evolution of game servers from centralized to ...distributed models, leading to the emergence of distributed game engines. These engines allow for the distribution of game engine modules (GEMs) across multiple servers, improving scalability and performance. However, this distribution presents a new challenge: the game engine module placement problem. This problem involves strategically placing GEMs to maximize the number of accepted placement requests while minimizing the delay experienced by players, a critical factor in enhancing the gaming experience. The problem can be formulated as an Integer Linear Programming (ILP) model, which provides an optimal solution but suffers from high computational complexity, making it impractical for real-world applications. To address this challenge, this paper introduces two novel heuristic algorithms, MAP-MIND and MAP-MIND*. The MAP-MIND algorithm demonstrates superior performance, achieving near-optimal delay and more than 92% GEM request acceptance in the worst heterogeneous scenarios. The MAP-MIND* algorithm, while slightly under-performing MAP-MIND in terms of delay, proves to be significantly faster, making it a viable alternative for real-world applications with equal GEM request acceptance. The trade-off between the two algorithms offers a flexible approach to GEM placement, balancing performance and computational efficiency.
In distributed SDN architectures, the network is controlled by a cluster of multiple controllers. This distributed approach permits to meet the scalability and reliability requirements of large ...operational networks. Despite that, a logical centralized view of the network state should be guaranteed, enabling the simple development of network applications. Achieving a consistent network state requires a consensus protocol, which generates control traffic among the controllers whose timely delivery is crucial for network performance. We focus on the state-of-art ONOS controller, designed to scale to large networks, based on a cluster of self-coordinating controllers, and concentrate on the inter-controller control traffic. Based on real traffic measurements, we develop a model to quantify the traffic exchanged among the controllers, which depends on the topology of the controlled network. This model is useful to design and dimension the control network interconnecting the controllers.
A
bstract
In this paper we consider axisymmetric black holes in supergravity and address the general issue of defining a first order description for them. The natural setting where to formulate the ...problem is the De Donder-Weyl-Hamilton-Jacobi theory associated with the effective two-dimensional sigma-model action describing the axisymmetric solutions. We write the general form of the two functions
S
m
defining the first-order equations for the fields. It is invariant under the global symmetry group
G
(3)
of the sigma-model. We also discuss the general properties of the solutions with respect to these global symmetries, showing that they can be encoded in two constant matrices belonging to the Lie algebra of
G
(3)
, one being the Nöther matrix of the sigma model, while the other is non-zero only for rotating solutions. These two matrices allow a
G
(3)
-invariant characterization of the rotational properties of the solution and of the extremality condition. We also comment on extremal, under-rotating solutions from this point of view.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Early in-vivo diagnosis of Alzheimer's disease (AD) is crucial for accurate management of patients, in particular, to select subjects with mild cognitive impairment (MCI) that may evolve into AD, and ...to define other types of MCI non-AD patients. The application of artificial intelligence to functional brain
Ffluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography(CT) aiming to increase diagnostic accuracy in the diagnosis of AD is still undetermined. In this field, we propose a radiomics analysis on advanced imaging segmentation method Statistical Parametric Mapping (SPM)-based completed with a Machine-Learning (ML) application to predict the diagnosis of AD, also by comparing the results with following Amyloid-PET and final clinical diagnosis.
From July 2016 to September 2017, 43 patients underwent PET/CT scans with FDG and Florbetaben brain PET/CT and at least 24 months of clinical/instrumental follow-up. Patients were retrospectively evaluated by a multidisciplinary team (MDT = Neurologist, Psychologist, Radiologist, Nuclear Medicine Physician, Laboratory Clinic) at the G. Giglio Institute in Cefalù, Italy. Starting from the cerebral segmentations applied by SPM on the main cortical macro-areas of each patient, Pyradiomics was used for the feature extraction process; subsequently, an innovative descriptive-inferential mixed sequential approach and a machine learning algorithm (i.e., discriminant analysis) were used to obtain the best diagnostic performance in prediction of amyloid deposition and the final diagnosis of AD.
A total of 11 radiomics features significantly predictive of cortical beta-amyloid deposition (
= 6) and AD (
= 5) were found. Among them, two higher-order features (original_glcm_Idmn and original_glcm_Id), extracted from the limbic enthorinal cortical area (ROI-1) in the FDG-PET/CT images, predicted the positivity of Amyloid-PET/CT scans with maximum values of sensitivity (SS), specificity (SP), precision (PR) and accuracy (AC) of 84.92%, 75.13%, 73.75%, and 79.56%, respectively. Conversely, for the prediction of the clinical-instrumental final diagnosis of AD, the best performance was obtained by two higher-order features (original_glcm_MCC and original_glcm_Maximum Probability) extracted from ROI-2 (frontal cortex) with a SS, SP, PR and AC of 75.16%, 80.50%, 77.68%, and 78.05%, respectively, and by one higher-order feature (original_glcm_Idmn) extracted from ROI-3 (medial Temporal cortex; SS = 80.88%, SP = 76.85%, PR = 75.63%, AC = 78.76%.
The results obtained in this preliminary study support advanced segmentation of cortical areas typically involved in early AD on FDG PET/CT brain images, and radiomics analysis for the identification of specific high-order features to predict Amyloid deposition and final diagnosis of AD.
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Users of device-to-device (D2D) communication need efficient content discovery mechanisms to steer their requests toward the node in their neighborhood that is most likely to satisfy them. The ...problem is further compounded by the lack of a central coordination entity as well as by the inherent mobility of devices, which leads to volatile topologies. In this paper, we first discuss group-based communication among non-rooted Android devices using Wi-Fi direct, a protocol recently standardized by the Wi-Fi alliance. We propose intra- and inter-group communication methodologies, which we validate through a simple testbed where content-centric routing is used. Next, we address the autonomous formation of groups with the goal of achieving efficient device resource utilization as well as full connectivity. Finally, we evaluate the performance of our group formation procedure both in simulation and in a real testbed involving Android devices in different topologies.
The aim of the present study consists of the evaluation of the biodistribution of a novel 68Ga-labeled radiopharmaceutical, 68GaGa-NODAGA-Z360, injected into Balb/c nude mice through ...histopathological analysis on bioptic samples and radiomics analysis of positron emission tomography/computed tomography (PET/CT) images. The 68Ga-labeled radiopharmaceutical was designed to specifically bind to the cholecystokinin receptor (CCK2R). This receptor, naturally present in healthy tissues such as the stomach, is a biomarker for numerous tumors when overexpressed. In this experiment, Balb/c nude mice were xenografted with a human epidermoid carcinoma A431 cell line (A431 WT) and overexpressing CCK2R (A431 CCK2R+), while controls received a wild-type cell line. PET images were processed, segmented after atlas-based co-registration and, consequently, 112 radiomics features were extracted for each investigated organ / tissue. To confirm the histopathology at the tissue level and correlate it with the degree of PET uptake, the studies were supported by digital pathology. As a result of the analyses, the differences in radiomics features in different body districts confirmed the correct targeting of the radiopharmaceutical. In preclinical imaging, the methodology confirms the importance of a decision-support system based on artificial intelligence algorithms for the assessment of radiopharmaceutical biodistribution.
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Blockchains offer trust and immutability in nontrusted environments, but most are not fast enough for latency-sensitive applications. Hyperledger fabric (HF) is a common enterprise-level platform ...that is being offered as blockchain-as-a-service by cloud providers. In HF, every new transaction requires a preliminary endorsement by multiple mutually untrusted parties called organizations, which contributes to the delay in storing the transaction in the blockchain. The endorsement policy is specific to each application and defines the required approvals by the endorser peers (EPs) of the involved organizations. In this article, given an input endorsement policy , we studied the optimal choice to distribute the endorsement requests to the proper EPs. We proposed the OPtimal ENdorsement (OPEN) algorithm, devised to minimize the latency due to both network delays and the processing times at the EPs. By extensive simulations, we showed that OPEN can reduce the endorsement latency up to 70% compared to the state-of-the-art solution and approximated well the introduced optimal policies while offering a negligible implementation overhead compared to them.
Scalability of Software Defined Networking (SDN) approach is one of the key issues that many network operators are willing to address and understand. Indeed, the promised programmability and ...flexibility of a SDN network is paid with a non-negligible control traffic exchanged between the network nodes and the SDN controllers. We consider a network controlled by a real OpenFlow-enabled controller, i.e. OpenDaylight. We evaluate analytically the number of OpenFlow messages for installing a new traffic flow, assuming the default reactive forwarding application available in OpenDaylight. We apply these results to the specific case of a large ISP network, comprising a backbone interconnecting many POPs. By evaluating exactly the amount of generated control traffic, we are able to assess the scalability of the reactive forwarding application in a practical relevant scenario for ISPs.
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