1,720,972 research outputs found
Spatially Distributed Molecular Communications via Diffusion: Second-Order Analysis
Full text linkUnlike electromagnetic communications, where the noise is typically represented by a (Gaussian) independent source which is added to the useful signal (additive noise), molecular communications via diffusion are affected by a random disturbance which is intrinsically related to the random nature of emission, propagation (Brownian motion) and reception. In point-to-point molecular communications, the number of received molecules is generally a Poisson random variable. Thus, the evaluation of the signal-to-noise ratio (intended as the ratio between the squared mean value of the received molecules and its variance) is not a problem of interest, since its value simply equals the mean of such a random variable. However, in spatially distributed communications, where the point transmitters are randomly placed in the 3D space according to a point process, the number of received molecules derives from the contribution of a random sum of emissions, so that it is no more a Poisson random variable. Thus, the evaluation of the signal-to-noise ratio is not trivial. Here, we provide an analytical framework to evaluate the signal-to-noise ratio in spatially distributed molecular communications for both synchronous and asynchronous transmitters. The analysis is extended to the signal-to-interference-noise ratio when digital communications with intersymbol interference are considered
Performance Limits of Spatially Distributed Molecular Communications With Receiver Saturation
Full text linkMolecular via diffusion are affected by unreliability and inter symbol interference in case of single transmitter. A promising solution to these issues appears to be the adoption of a swarm of randomly distributed transmitting nano-devices and a single spherical receiver. However, such a perspective assumes the receiver as fully absorbing (i.e., able to absorb an unlimited number of molecules per second). In this letter, we show that, if this assumption is relaxed, increasing the number of point transmitters leads to a saturation effect which makes communication impossible when digital transmission is considered. By means of a first and second order spatio-temporal stochastic model, we analytically derive the maximum allowed point transmitters density before saturation arises, as a function of parameters such as the diffusion coefficient, the maximum number of absorbed molecules, and the number of previously transmitted symbols. The analysis is validated via Monte Carlo simulation
Impact of Partial Equalization on the Downlink Performance of Multi-Carrier CDMA Systems
No full textIn this paper we analytically evaluate the downlink performance of multi-carrier code division multiple access systems adopting a partial equalization technique. This technique, that depends on a parameter which can be adapted to different conditions such as the number of sub-carriers, the number of active users and the mean signal-to-noise ratio, is proposed and analytically studied. We derive the performance of this system and the value of the equalization parameter that maximizes the performance. The proposed technique is shown to have the same complexity of the well known maximal ratio combining, equal gain combining and orthogonal restoring combining techniques, with significative performance improvement
On the Down-Link Performance of Multi-Carrier CDMA Systems with Partial Equalization
No full textThis paper addresses the performance evaluation
of multi-carrier code division multiple access systems. A partial
equalization technique depending on a parameter adapted to different
conditions such as the number of sub-carriers, the number
of active users and the mean signal-to-noise ratio is evaluated
for the down-link. We analytically derive the performance of
this system and the value of the equalization parameter that
maximizes the performance. The partial equalization technique
is shown to have the same complexity of the well known maximal
ratio combining, equal gain combining and orthogonality
restoring combining techniques, with significative performance
improvement. Analytical results are compared with simulations
showing a perfect agreement
Whole wheat bread enriched with silver fir (Abies alba Mill.) needles extract: technological and antioxidant properties
Full text linkBACKGROUND: The interest of consumers and market and scientific research for added-value foods obtained with environmentally sustainable productive chains is increasing. Silver fir (Abies alba Mill.) needles (SFNs), often by-products of forest management and logging, represent an unexploited source of bioactive compounds. RESULTS: For the first time, SFN aqueous extract obtained through controlled hydrodynamic cavitation was used to enrich whole wheat flour bread. The first trial found that 35% SFNs extract addition was the absolute threshold of taste perception. The second trial investigated dough rheological properties and bread technological and antioxidant properties in samples enriched with 35% and 100% SFNs extract compared with the control (0% SFNs extract). SFNs extract significantly increased bread antioxidant capacity in both 35% and 100% SFN fresh breads by ~42.5% and ~87% respectively and in 100% SFNs bread samples after 72 h of storage by ~76%. Enrichment of 35% showed higher alveograph dough extensibility (~11%) and different bread texture in terms of hardness, springiness, and chewiness. Enrichment with 100% SFNs extract significantly improved dough and bread technological quality: it increased alveograph dough extensibility L (~18%), swelling index G (~8%), and flour strength W (~14%) and showed the highest increase in bread specific volume (~0.200 L kg−1). CONCLUSIONS: SFNs aqueous extract produced with controlled hydrodynamic cavitation appeared a valuable technical material for the manufacturing of added-value and functional breads. © 2021 Society of Chemical Industry
An Overview of the Health Benefits, Extraction Methods and Improving the Properties of Pomegranate
Full text linkPomegranate (Punica granatum L.) is a polyphenol-rich edible food and medicinal plant of ancient origin, containing flavonols, anthocyanins, and tannins, with ellagitannins as the most abundant polyphenols. In the last decades, its consumption and scientific interest increased, due to its multiple beneficial effects. Pomegranate is a balausta fruit, a large berry surrounded by a thick colored peel composed of exocarp and mesocarp with edible arils inside, from which the pomegranate juice can be produced by pressing. Seeds are used to obtain the seed oil, rich in fatty acids. The non-edible part of the fruit, the peel, although generally disposed as a waste or transformed into compost or biogas, is also used to extract bioactive products. This review summarizes some recent preclinical and clinical studies on pomegranate, which highlight promising beneficial effects in several fields. Although further insight is needed on key aspects, including the limited oral bioavailability and the role of possible active metabolites, the ongoing development of suitable encapsulation and green extraction techniques enabling the valorization of waste pomegranate products point to the great potential of pomegranate and its bioactive constituents as dietary supplements or adjuvants in therapies of cardiovascular and non-cardiovascular diseases
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Design, deployment and evolution of heterogeneous smart public lighting systems
Full text linkStreet lighting characterizes many smart city initiatives around the world. In fact, significant savings can be achieved by not only replacing traditional luminaires with low-power LEDs, but also providing streetlights with smart light controllers and network connectivity, allowing the introduction of a sensible light intensity management and reduction of maintenance costs. Moreover, if designed with a far-looking view, smart lighting infrastructure could also support city-wide Internet of Things services, becoming key enablers of the smart city revolution, also in the 5G perspective. In this paper, we provide a thorough discussion on network architectures and communication technologies that could be adopted for smart public lighting applications, showing their benefits and downsides. Starting with significant activity on research, implementation and in-field testing, we also outline the steps required for the deployment of a smart public lighting infrastructure, each discussed in accordance with the network topology considered. Finally, we introduce some additional services that a smart public lighting infrastructure could support and discuss the benefits that would arise from integration with the upcoming 5G cellular network
Comprehensive Assessment of Context-Adaptive Street Lighting: Technical Aspects, Economic Insights, and Measurements from Large-Scale, Long-Term Implementations
Full text linkThis paper addresses the growing importance of efficient street lighting management, driven by rising electricity costs and the need for municipalities to implement cost-effective solutions. Central to this study is the UNI 11248 Italian regulation, which extends the European EN 13201-1 standard introduced in 2016. These standards provide guidelines for designing, installing, operating, and maintaining lighting systems in pedestrian and vehicular traffic areas. Specifically, the UNI 11248 standard introduces the possibility to dynamically adjust light intensity through two alternative operating modes: (a) Traffic Adaptive Installation (TAI), which dims the light based solely on real-time traffic flow measurements; and (b) Full Adaptive Installation (FAI), which, in addition to traffic measurements, also requires evaluating road surface luminance and meteorological conditions. In this paper, we first present the general architecture and operation of an FAI-enabled lighting infrastructure, which relies on environmental sensors and a heterogeneous wireless communication network to connect intelligent, remotely controlled streetlights. Subsequently, we examine large-scale, in-field FAI infrastructures deployed in Vietnam and Italy as case studies, providing substantial measurement data. The paper offers insights into the measured energy consumption of these infrastructures, comparing them to that of conventional light-control strategies used in traditional installations. The measurements demonstrate the superiority of FAI as the most efficient solution
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