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showing 10 items of 6139 documents
Comparative Analysis of Modified Modulation Scheme for Three-phase Voltage fed QZS Inverters
2019
Single-stage converters are one promising solution in different field of applications. In particular, quasi-Z-Source VSI topology structure playsan important role because it presents the same advantages of VSI and qZS converters. In addition, it allows increasing the inverter reliability. Moreover, modulation schemes and control strategy are still being developed. For this reason, aim of this paper is to introduce a modified modulation scheme based on the Maximum Constant Boost Control (MCBC) concept and Switching Frequency Optimal (SFO)as reference signals that represents the novelty issue of this work. The analysis has been carried out by comparing the performance of the converter in term…
An asynchronous covert channel using spam
2012
AbstractCurrent Internet e-mail facilities are built onto the foundation of standard rules and protocols, which usually allow a considerable amount of “freedom” to their designers. Each of these standards has been defined based on a number of vendor specific implementations, in order to provide common inter-working procedures for cross-vendor communication. Thus, a lot of optional and redundant information is being exchanged during e-mail sessions, which is available to implement versatile covert channel mechanisms.This work exploits this possibility by presenting a simple but effective steganographic scheme that can be used to deploy robust secret communication through spam e-mails. This s…
Energy-Efficient Context-Aware Resource Allocation for Edge-Computing-Empowered Industrial IoT
2020
Edge computing provides a promising paradigm to support the implementation of industrial Internet of Things (IIoT) by offloading computational-intensive tasks from resource-limited machine-type devices (MTDs) to powerful edge servers. However, the performance gain of edge computing may be severely compromised due to limited spectrum resources, capacity-constrained batteries, and context unawareness. In this chapter, we consider the optimization of channel selection which is critical for efficient and reliable task delivery. We aim at maximizing the long-term throughput subject to long-term constraints of energy budget and service reliability. We propose a learning-based channel selection fr…
Editorial: Mining Scientific Papers: NLP-enhanced Bibliometrics
2019
International audience
Wireless sensor network for Spectrum Cartography based on Kriging interpolation
2012
Dynamic spectrum access with Cognitive Radio (CR) network is a promising approach to increase the efficiency of spectrum usage. To allow the optimization of resource allocation and transmission adaptation techniques, each CR terminal needs to acquire awareness of the state of the time-frequency-location varying radio spectrum. In this paper we present a Spectrum Cartography (SC) approach where CR terminals are supported by a fixed wireless sensor network (WSN) to estimate and update the Power Spectral Density (PSD) over the area of interest. The wireless sensors collaborate to estimate the spatial distribution of the received power at a given frequency using either a centralized or a distri…
MDP-based Resource Allocation for Uplink Grant-free Transmissions in 5G New Radio
2020
The diversity of application scenarios in 5G mobile communication networks calls for innovative initial access schemes beyond traditional grant-based approaches. As a novel concept for facilitating small packet transmission and achieving ultra-low latency, grant-free communication is attracting lots of interests in the research community and standardization bodies. However, when a network consists of both grant based and grant-free based end devices, how to allocate slot resources properly between these two categories of devices remains as an unanswered question. In this paper, we propose a Markov decision process based scheme which dynamically allocates grant-free resources based on a spec…
Developing scoring functions to assess soil quality at a regional scale in rangelands of SW Spain
2020
ABSTRACT The drawing of maps of soil quality at a large scale is increasingly being more useful to land planners and stakeholders. Nevertheless, it involves different methodological steps from the description of soil profiles in the field until the regional mapping of integrative soil quality index (IQI) values. The development of proper scoring functions is a paramount task for the calculation of these IQI values since every parameter needs to be standardized accordingly and weighting factors are usually estimated by multivariate techniques. The main goal of this study was to map soil quality in the Spanish region of Extremadura (commonly known by its rangelands called dehesas). To do that…
Resource sharing optimality in WiFi infrastructure networks
2009
In WiFi networks, mobile nodes compete for accessing a shared channel by means of a random access protocol called Distributed Coordination Function (DCF). Although this protocol is in principle fair, since all the stations have the same probability to transmit on the channel, it has been shown that unfair behaviors may emerge in actual networking scenarios. Assuming that a contending node can dynamically change its strategy, by tuning its contention parameters to non-standard values on the basis of channel observations, we prove that, for infrastructure networks with bidirectional traffic and homogeneous application requirements, selfish access strategies are able to reach equilibrium condi…
NoC Reconfiguration for CMP Virtualization
2011
At NoC level, the traffic interferences can be drastically reduced by using virtualization mechanisms. An effective strategy to virtualize a NoC consists in dividing the network in different partitions, each one serving different applications and traffic flows. In this paper, we propose a NoC reconfiguration mechanism to support NoC virtualization under real scenarios. Dynamic reassignment of network resources to different partitions is allowed in order to NoC dynamically adapts to application needs. Evaluation results show a good behavior of CMP virtualization.
Energy-Efficient M2M Communications in for Industrial Automation
2020
M2M communication with autonomous data acquisition and exchange plays a key role in realizing the “control”-oriented tactile Internet (TI) applications such as industrial automation. In this chapter, we develop a two-stage access control and resource allocation algorithm. In the first stage, we introduce a contract-based incentive mechanism to motivate some delay-tolerant machine-type communication (MTC) devices to postpone their access demands in exchange for higher access opportunities. In the second stage, a long-term cross-layer online resource allocation approach is based on Lyapunov optimization, which jointly optimizes rate control, power allocation, and channel selection without pri…