Telecom Italia Mobile

About: Telecom Italia Mobile is a based out in . It is known for research contribution in the topics: Cloud computing & UMTS frequency bands. The organization has 72 authors who have published 63 publications receiving 1277 citations.

An analytic solution for the perspective 4-point problem

Abstract: The perspective n-point (PnP) problem is the problem of finding the position and orientation of a camera with respect to a scene object from n correspondence points. The authors propose an analytic solution for the perspective 4-point problem. The solution is found by replacing the four points with a pencil of three lines and by exploring the geometric constraints available with the perspective camera model. The P4P problem is cast into the problem of solving a biquadratic polynomial equation in one unknown.

In vitro exposure of human lymphocytes to 900 MHz CW and GSM modulated radiofrequency: studies of proliferation, apoptosis and mitochondrial membrane potential.

Abstract: The aim of this study was to investigate the nonthermal effects of radiofrequency (RF) fields on human immune cells exposed to a Global System for Mobile Communication (GSM) signal generated by a commercial cellular phone and by a sinusoidal non-modulated signal. To assess whether mobile phone RF-field exposure affects human immune cell functions, peripheral blood mononuclear cells (PBMCs) from healthy donors were exposed in vitro to a 900 MHz GSM or continuous-wave (CW) RF field 1 h/day for 3 days in a transverse electromagnetic mode (TEM) cell system (70-76 mW/kg average specific absorption rate, SAR). The cells were cultured for 48 or 72 h, and the following end points were studied: (1) mitogen-induced proliferation; (2) cell cycle progression; (3) spontaneous and 2-deoxy-D-ribose (dRib)-induced apoptosis; (4) mitochondrial membrane potential modifications during spontaneous and dRib-induced-apoptosis. Data obtained from cells exposed to a GSM-modulated RF field showed a slight decrease in cell proliferation when PBMCs were stimulated with the lowest mitogen concentration and a slight increase in the number of cells with altered distribution of phosphatidylserine across the membrane. On the other hand, cell cycle phases, mitochondrial membrane potential and susceptibility to apoptosis were found to be unaffected by the RF field. When cells were exposed to a CW RF field, no significant modifications were observed in comparison with sham-exposed cells for all the end points investigated.

Fault-tolerant rate-monotonic first-fit scheduling in hard-real-time systems

Abstract: Hard-real-time systems require predictable performance despite the occurrence of failures. In this paper, fault tolerance is implemented by using a novel duplication technique where each task scheduled on a processor has either an active backup copy or a passive backup copy scheduled on a different processor. An active copy is always executed, while a passive copy is executed only in the case of a failure. First, the paper considers the ability of the widely-used rate-monotonic scheduling algorithm to meet the deadlines of periodic tasks in the presence of a processor failure. In particular, the completion time test is extended so as to check the schedulability on a single processor of a task set including backup copies. Then, the paper extends the well-known rate-monotonic first-fit assignment algorithm, where all the task copies, included the backup copies, are considered by rate-monotonic priority order and assigned to the first processor in which they fit. The proposed algorithm determines which tasks must use the active duplication and which can use the passive duplication. Passive duplication is preferred whenever possible, so as to overbook each processor with many passive copies whose primary copies are assigned to different processors. Moreover, the space allocated to active copies is reclaimed as soon as a failure is detected. Passive copy overbooking and active copy deallocation allow many passive copies to be scheduled sharing the same time intervals on the same processor, thus reducing the total number of processors needed. Simulation studies reveal a remarkable saving of processors with respect to those needed by the usual active duplication approach in which the schedule of the non-fault-tolerant case is duplicated on two sets of processors.

LoRaWAN: Evaluation of Link- and System-Level Performance

Abstract: The Internet of Things (IoT) addresses a huge set of possible application domains, requiring both short- and long-range communication technologies. When long distances are present, a number of proprietary and standard solutions for low power wide area networks are already available. Among them, LoRaWAN is a candidate technology supported by many network operators. This paper discusses the possible role of LoRaWAN for the IoT. First, the LoRaWAN technology is assessed experimentally through a set of laboratory and on-field tests, to characterize it from the link-level viewpoint; then, a system-level analysis is performed through simulation, to evaluate the capacity of an LoRaWAN gateway and a multigateway network to serve a large area. Finally, the results are discussed considering a broad set of use cases.

An analytic solution for the perspective 4-point problem

Abstract: The perspective n-point (PnP) problem is the problem of finding the position and orientation of a camera with respect to a scene object from n correspondence points. The authors propose an analytic solution for the perspective 4-point problem. The solution is found by replacing the four points with a pencil of three lines and by exploring the geometric constraints available with the perspective camera model. The P4P problem is cast into the problem of solving a biquadratic polynomial equation in one unknown. >