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Millimeter wave (mmWave) localization algorithms exploit the quasi-optical propagation of mmWave signals, which yields sparse angular spectra at the receiver. Geometric approaches to angle-based localization typically require to know the map of the environment and the location of the access points. Thus, several works have resorted to automated learning in order to infer a device's location from the properties of the received mmWave signals. However, collecting training data for such models is a significant burden. In this work, we propose a shallow neural network model to localize mmWave devices indoors. This model requires significantly fewer weights than those proposed in the literature. Therefore, it is amenable for implementation in resource-constrained hardware, and needs fewer training samples to converge. We also propose to relieve training data collection efforts by retrieving (inherently imperfect) location estimates from geometry-based mmWave localization algorithms. Even in this case, our results show that the proposed neural networks perform as good as or better than state-of-the-art algorithms., 6 pages, 9 figures. The paper was accepted at IEEE WCNC 2022

Cloud applications are exposed to workloads whose intensity can change unpredictably over time. Hence, the ability to quickly scale the amount of computing resources provisioned to applications is essential to minimize costs while providing reliable services. In this context,containers are deemed to be a promising technology to enable fast elasticity in resource allocation schemes.In this paper, we propose and experimentally test an efficient container-based cloud computing provisioning system. First, we address the container deployment problem and discuss how to manage container provisioning and scaling. Second, we devise are source management mechanism leveraging on both admission control and auto-scaling techniques. We propose to drive auto-scaling decisions through a Q-Learning algorithm, which is agnostic to the specific computing environment, and proceeds based only on the load of the physical processors assigned to a container. We evaluate our solution in two experimental setups,and show that it yields significant advantages when compared to popular container managers such as Kubernetes. TRUE pub

Tourism promotion is one of the most relevant elements in the development of a geographical area, both in economic, cultural and social terms. A correct representation of the points of interest in a territory with respect to the different tourist targets, allows to propose a better experiential offer for the tourist, improving the attractiveness of that territory as a whole.This work analyzes a solution aimed at creating optimal experiential paths for the tourist, where, starting from a set of boundary conditions (interests, time available, physical fitness, mode of travel), a choice of itineraries is proposed within the geographical area of interest.The application infrastructure is based on the use of operations research algorithms [decision algorithms] and GIS technology.

Open source software projects usually acknowledge contributions with text files, websites, and other idiosyncratic methods. These data sources are hard to mine, which is why contributorship is most frequently measured through changes to repositories, such as commits, pushes, or patches. Recently, some open source projects have taken to recording contributor actions with standardized systems; this opens up a unique opportunity to understand how community-generated notions of contributorship map onto codebases as the measure of contribution. Here, we characterize contributor acknowledgment models in open source by analyzing thousands of projects that use a model called All Contributors to acknowledge diverse contributions like outreach, finance, infrastructure, and community management. We analyze the life cycle of projects through this model's lens and contrast its representation of contributorship with the picture given by other methods of acknowledgment, including GitHub's top committers indicator and contributions derived from actions taken on the platform. We find that community-generated systems of contribution acknowledgment make work like idea generation or bug finding more visible, which generates a more extensive picture of collaboration. Further, we find that models requiring explicit attribution lead to more clearly defined boundaries around what is and what is not a contribution., Comment: Extended version of a paper accepted at MSR 2021

We propose a method to let a source and a destination agree on a key that remains secret to a potential eavesdropper in an underwater acoustic network (UWAN). We generate the key from the propagation delay measured over a set of multihop routes: this harvests the randomness in the UWAN topology and turns the slow sound propagation in the water into an advantage for the key agreement protocol. Our scheme relies on a route discovery handshake. During this process, all intermediate relays accumulate message processing delays, so that both the source and the destination can compute the actual propagation delays along each route, and map this information to a string of bits. Finally, via a secret key agreement from the information-theoretic security framework, we obtain an equal set of bits at the source and destination, which is provably secret to a potential eavesdropper located away from both nodes. Our simulation results show that, even for small UWANs of 4 nodes, we obtain 11 secret bits per explored topology, and that the protocol is insensitive to an average node speed of up to 0.5 m/s.

We report the details of ASUNA, a freely shared dataset for underwater network emulation (ASUNA). ASUNA tackles the time-consuming and costly logistics of multiple underwater networking sea trials by providing a benchmark database of time-varying network topologies recorded across multiple sea experiments, thus facilitating experiment replay and network emulation. The ASUNA database currently includes 20 diverse, time-varying topology structures, multimodal communication technologies, and different link quality measurements. With the aim of becoming a standard benchmark, ASUNA is open to extensions as new data becomes available from the underwater communications community. We provide the details of ASUNA structure, the list of recorded topologies, as well as examples of how to use the database as part of an emulation system to test the performance of two scheduling protocols. We freely share the database and the emulation code both through a web server and via the Code Ocean repository. pub

Underwater wireless communications (UWC) has been playing an important role in marine activities for the second half of the 20th century. Ranging from military purposes in its early stages to today’s industrial and non-profit applications such as environmental monitoring, oceanographic data collection, disaster monitoring, and underwater resource exploration, there has been a growing interest in the realization of underwater wireless networks. However, practical applications often require significant data bandwidth. Such requirements are not always met by the design of current UWC systems, which are challenged by the unique and harsh conditions of underwater communication channels, including for example severe attenuation, multipath dispersion, and limited capability to exploit channel resources. Recently, many academic and industrial researchers have worked on the improvement of UWC systems by augmenting them with state-of-the-art information and communication technologies. There have been reports of new results and insight on the fundamental theories and practical implementations of UWC systems, i.e., UWC channel models and estimation, digital signal processing, advanced transceiver design, multiple access (MAC), and routing and upper-layer protocols, aswell as successful cross-layer design implementations.

Millimeter wave (mmWave) location systems not only provide accurate positioning for location-based services, but can also help optimize network operations, for example through location-driven beam steering and access point association. In this paper, we design and evaluate localization schemes that exploit the characteristics of mmWave communication systems. We propose two range-free algorithms belonging to the broad classes of triangulation and angle difference-of-arrival. The schemes work both with multiple anchors and with as few as a single anchor, under the only assumption that the floor plan and the positions of the mmWave access points are known. Moreover, they are designed to be lightweight, so that even computationally-constrained devices can run them. We evaluate our proposed algorithms against two benchmark approaches based on fingerprinting and angles of arrival, respectively. Our results, obtained both by means of simulations and through measurements involving commercial 60-GHz mmWave devices, show that sub-meter accuracy is achieved in most of the cases, even in the presence of only a single access point. The availability of multiple access points substantially improves the localization accuracy, especially for large indoor spaces. pub

In this paper, we propose Li-Tect, an algorithm to detect the shape of an object located in an indoor environment using low cost optical elements through sensing the environment's light. The algorithm analyzes, relying on the predictability of optical propagation paths, how much light is expected to propagate in the absence of obstructions caused by the presence of an object. Then, based on the received light when the object is in the room, the algorithm infers the shape of the object. In addition, the algorithm considers the reflected paths from surfaces in order to determine the object's estimated shape. We study five different scenarios characterized by different levels of complexity, room sizes, and a range of reflection nodes. The algorithm is also tested in a real prototype where several experiments are carried out in two scenarios to demonstrate the capabilities of Li-Tect in 2-D and 3-D monitoring and shape detection cases. Finally, the results show that the shape and the detection of objects in the scenarios can be easily acquired with high accuracy, even if the number of transceivers is reduced. This work was supported in part by the Spanish Government under the National Projects “ELISA” and “TERESA-ADA” with ID TEC2014-59255-C3-3-R and TEC2017-90093-C3-2-R, respectively and in part by the European project called VisIoN. This work has been finalized under the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement 764461. Publicado

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We consider the problem of estimating the trajectory of a submerged source emitting acoustic signals without using any anchor nodes or receiving array. This approach is required for several applications, including the localization of acoustic sources such as marine mammals or underwater vehicles, for which the cost of covering a broad area with multiple receivers would be excessively high. Since multi-lateration is impossible in this scenario, we perform localization by incorporating bathymetry information. Specifically, we assume that the receiver retains knowledge of the environmental parameters that affect the signal propagation, and that the bathymetry of the area is sufficiently diverse to induce distinguishable channel impulse responses for different source locations. Our method compares the channel estimates obtained from the received acoustic signals against a database of channel responses, pre-computed through an acoustic ray tracing model. The set of possible node locations that result are then organized in trellis form to obtain a final estimate of the source's trajectory via a path tracking method similar to the Viterbi algorithm. Our results show that the proposed approach can estimate node locations and paths with very small error, provided that the receiver has sufficiently accurate and up-to-date environmental information. TRUE pub

We consider a multihop network where a source node must reliably deliver a set of data packets to a given destination node. To do so, the source applies a fountain code and floods the encoded packets through the network, until they reach their destination or are lost in the process. We model the probability that the destination can recover the original transmissions from the received coded packets as a function of the network topology and of the code redundancy, and show that our analytical results predict the outcome of simulations very well. These results are employed to design distributed forwarding policies that achieve a good tradeoff between the success probability and the total number of transmissions required to advance a packet towards the destination. We finally develop in detail the case where intermediate relays can inject additional redundancy in the network, provided that they have successfully decoded the source packets. pub

We consider a range estimation algorithm based on the time-of-arrival differences between multipath replicas of a signal transmitted by an anchor node of known location to a silent node that needs to localize itself. We consider the geometry of the problem in the simplified case of a constant sound speed profile (SSP), and argue that the more realistic case of a non- constant SSP can be still tackled as if the SSP were constant, provided that an “effective” sound speed value is computed based on the geometry of the signal propagation. We finally evaluate the accuracy of the latter approach in the presence of errors affecting different quantities required for the range estimation process, including the TDoA values and the bottom depth. Our results show that our approach offers improved accuracy with respect to a baseline LSE estimator. TRUE pub