Résultats de recherche pour « Communication »

This paper, based on recent research, articulates the opportunities and challenges posed by an emerging area of study known as ``mediumband wireless communication'', which refers to digital radio-frequency (RF) wireless communication through mediumband channels. This class of channels that falls in the transitional region between the narrowband and broadband channels, in many ways, is unique and shows significant potential. For instance, the effect of a highly unfavourable non-line-of-sight (NLoS) propagation environment can be transformed into a significantly favourable condition without making any intervention on the original propagation environment, but by simply communicating in the mediumband. The more unfavourable a propagation environment for wireless communication, the higher the potential gain by communicating in the mediumband. In this paper, using lay language as much as possible, we elaborate the unique properties of mediumband channels and implications of communicating in the mediumband for wider wireless communication along with some future research directions.

Communication among microscopic robots (nanorobots) can coordinate their activities for biomedical tasks. The feasibility of in vivo ultrasonic communication is evaluated for micron-size robots broadcasting into various types of tissues. Frequencies between 10MHz and 300MHz give the best tradeoff between efficient acoustic generation and attenuation for communication over distances of about 100 microns. Based on these results, we find power available from ambient oxygen and glucose in the bloodstream can readily support communication rates of about 10,000 bits/second between micron-sized robots. We discuss techniques, such as directional acoustic beams, that can increase this rate. The acoustic pressure fields enabling this communication are unlikely to damage nearby tissue, and short bursts at considerably higher power could be of therapeutic use.

“We are all regular people seeking the same thing: the guy on the street, the woman in the classroom, the Israeli, the Afghani, the Zuni, the Apache, the Irish, the Protestant, the Catholic, the gay, the straight, you, me—we all just want to know that we matter. We want validation.”

Blocking is one of the most important challenges in exploiting millimeter-wave for fifth-generation (5G) cellular communication systems. Compared to blockages caused by buildings or terrains, human body blockage exhibits a higher complexity due to the mobility and dynamic statistics of humans. To support development of outdoor millimeter-wave cellular systems, in this paper we present a novel 3D physical model of human body blockage. Based on the proposed model, the impact of human body blockage on frame-based data transmission is discussed, with respect to the system specifications and environment conditions.

From Chapter 1, "By Way of Introduction": "The orientation of this book is strongly biased in two directions; it is scientific, and it is psychological.A scientific study of language, as opposed to a speculative discussion, begins with direct observations of communicating individuals and searches for the relation of these observations to the existing body of scientific knowledge.There exist many speculations of a literary or philosophical nature that are inter- esting and stimulate the imagination; unless these speculations lead to scientific observations and generalizations, they are not discussed here.Rejecting opinions in favor of facts helps to reduce this vast topic to manageable proportions.The psychological bias restricts the discussion to the effects of language on the behavior of the individual.Psychology is the science of behavior.Our present interest is not in language as one of the social graces, but as a kind of cooperative human behavior."

A number of transmission models for airborne pathogens transmission, as required to understand airborne infectious diseases such as COVID-19, have been proposed independently from each other, at different scales, and by researchers from various disciplines. We propose a communication engineering approach that blends different disciplines such as epidemiology, biology, medicine, and fluid dynamics. The aim is to present a unified framework using communication engineering, and to highlight future research directions for modeling the spread of infectious diseases through airborne transmission. We introduce the concept of mobile human ad hoc networks (MoHANETs), which exploits the similarity of airborne transmission-driven human groups with mobile ad hoc networks and uses molecular communication as the enabling paradigm. In the MoHANET architecture, a layered structure is employed where the infectious human emitting pathogen-laden droplets and the exposed human to these droplets are considered as the transmitter and receiver, respectively. Our proof-of-concept results, which we validated using empirical COVID-19 data, clearly demonstrate the ability of our MoHANET architecture to predict the dynamics of infectious diseases by considering the propagation of pathogen-laden droplets, their reception and mobility of humans.

Scientific debates in modern societies often blur the lines between the science that is being debated and the political, moral, and legal implications that come with its societal applications. This manuscript traces the origins of this phenomenon to professional norms within the scientific discipline and to the nature and complexities of modern science and offers an expanded model of science communication that takes into account the political contexts in which science communication takes place. In a second step, it explores what we know from empirical work in political communication, public opinion research, and communication research about the dynamics that determine how issues are debated and attitudes are formed in political environments. Finally, it discusses how and why it will be increasingly important for science communicators to draw from these different literatures to ensure that the voice of the scientific community is heard in the broader societal debates surrounding science.

In the ever-evolving field of digital communication systems, complex-valued neural networks (CVNNs) have become a cornerstone, delivering exceptional performance in tasks like equalization, channel estimation, beamforming, and decoding. Among the myriad of CVNN architectures, the phase-transmittance radial basis function neural network (PT-RBF) stands out, especially when operating in noisy environments such as 5G MIMO systems. Despite its capabilities, achieving convergence in multi-layered, multi-input, and multi-output PT-RBFs remains a daunting challenge. Addressing this gap, this paper presents a novel Deep PT-RBF parameter initialization technique. Through rigorous simulations conforming to 3GPP TS 38 standards, our method not only outperforms conventional initialization strategies like random, $K$-means, and constellation-based methods but is also the only approach to achieve successful convergence in deep PT-RBF architectures. These findings pave the way to more robust and efficient neural network deployments in complex digital communication systems.

Abstract: Prominent accounts of language use (those of Grice, Lewis, Stalnaker, Sperber and Wilson among others) have viewed basic communicative acts as essentially involving the attitudes of the participating agents. Developmental data poses a dilemma for these accounts, since it suggests children below age four are competent communicators but would lack the ability to conceptualise communication if philosophers and linguists are right about what communication is. This paper argues that this dilemma is quite serious and that these prominent accounts would be undermined if an adequate more minimal alternative were available. Just such a minimalist account of communication is offered, drawing on ideas from relevance theory and situation theory.