2,770 research outputs found
Role of mycobacteria-induced monocyte/macrophage apoptosis in the pathogenesis of human tuberculosis
Attenuating information in spoken communication: For the speaker, or for the addressee?
Speakers tend to attenuate information that is predictable or repeated. To what extent is
this done automatically and egocentrically, because it is easiest for speakers themselves,
and to what extent is it driven by the informational needs of addressees? In 20 triads of
naive subjects, speakers told the same Road Runner cartoon story twice to one addressee
and once to another addressee, counterbalanced for order (Addressee1/Addressee1/
Addressee2 or Addressee1/Addressee2/Addressee1). Stories retold to the same (old)
addressees were attenuated compared to those retold to new addressees; this was true
for events mentioned, number of words, and amount of detail. Moreover, lexically identical
expressions by the same speaker were more intelligible to another group of listeners when
the expressions had been addressed to new addressees than when they had been
addressed to old addressees. We conclude that speakersâ attenuating of information in
spontaneous discourse is driven at least in part by addressees. Such audience design is computationally
feasible when it can be guided by a ââone-bitâ model (my audience has heard
this before, or not)
Separation of SSR signals by array processing in multilateration systems
Location and identification of cooperating aircraft in the airport area (and beyond) may be implemented by multilateration (MLAT) systems using the secondary surveillance radar (SSR) mode S signals. Most of these signals, spontaneously emitted from on-board mode S transponders at a fixed carrier frequency, arrive randomly at the receiving station, as well as many mode A/C replies from legacy transponders still in use. Several SSR signals are, then, overlapped in multiple aircraft situations. Therefore, the aim of this work is the separation of overlapped SSR signals, i.e., signals superimposed in time at receiving stations. We improve the MLAT receiving station by replacing the single antenna by an array of m elements and using array signal processing techniques. In the literature, several algorithms address the general source separation problem, but a very few of them are specifically designed for a mixture of overlapping SSR replies. Unfortunately, all of them have either some shortcomings, or an expensive computational cost, or no simple practical implementation. In this paper, we use the time sparsity property of the sources to propose more reliable, simpler, and more effective algorithms based on projection techniques to separate multiple SSR signals. Real recorded signals in a live environment are used to demonstrate the effectiveness of our method
ADS-B signals reception: a Software Defined Radio approach
In Air Traffic Control, ADS-B (Automatic
Dependent Surveillance - Broadcast) systems provide
surveillance information as obtained by the cooperating
airplanes. This usage of air-derived data and of a common link
opens various issues: performance in dense traffic area, signals
validation and security. A Software Defined Radio (SDR) permits
the needed flexibility and modularity in order to easily develop
prototypal devices for evaluation and test of novel enhancements
of ADS-B receivers. In this frame, a multi-channel receiver for
1090 MHz ADS-B signals was implemented, using an array
antenna, a specific designed analog front-end and a software
defined receiver. The device is useful to test signal processing
algorithms and to analyse the channel traffic. The receiver is also
jointly used with another SDR device capable to generate 1090
MHz traffic. With this configuration it is possible to generate
specific traffic scenarios characterized by interferences from
multiple sources and/or by jammer. This paper deals with the
hardware and set-up description, the presentation of the
developed software receiver and its functions, and, finally, the
results achieved using the system
Improved MDA, a case for de-garbling SSR mode S replies
Multilateration (MLAT) and Automatic
Dependent Surveillance â Broadcast (ADS-B) systems
exploiting the Secondary Surveillance Radar (SSR)
channel suffer from garbling. This means that if two or
more mode S signals impinge on the receiver at the same
or very near time they could not be decoded. To alleviate
this problem, many solutions have been proposed, one
in particular [1] is effective for a large variety of
scenarios, but excluding the cases when the replies are
too much separated in time. Recently a paper [2] focused
on linear algebra presented a potential solution for this
case. In this work we present a practical application for
the case of two mode S signals
Sicilian floriculture companies and the role of transport in increasing their competitiveness
The aim of this study is to provide a deeper understanding of the Sicilian floriculture sector, which has recently become one of the most important on a regional and national scale. By analysing production, sales and logistical aspects of its production companies and specifically looking at aspects regarding transport logistics, this study highlights the sector operators. preference for road transport that offers better guarantees in terms of delivery speed with respect to other means of transport, an essential requirement for the transport of flowers and plants. However, operators are increasingly showing interest in alternative means of transport that may reduce transport time and, especially, costs. Some of the operators interviewed believe that the expected building of 7 trucking terminals in Sicily represents an important move of the Regional Government to support companies; nevertheless, others think that this type of intervention represents an erosive element in competitiveness, because of the probable increase in the presence of goods coming from the southern Mediterranean shore. However, the improvement of the regional transport system is necessary to reduce inefficiencies in the sales and distribution network of the floriculture industry and, more in general, of the whole Sicilian agri-food industry
Speakers adapt gestures to addressees' knowledge: Implications for models of co-speech gesture.
Are gesturing and speaking shaped by similar communicative constraints? In an experiment, we teased apart
communicative from cognitive constraints upon multiple dimensions of speech-accompanying gestures in spontaneous
dialogue. Typically, speakers attenuate old, repeated or predictable information but not new information. Our
study distinguished what was new or old for speakers from what was new or old for (and shared with) addressees. In
20 groups of 3 naive participants, speakers retold the same Road Runner cartoon story twice to one addressee and
once to another. We compared the distribution of gesture types, and the gesturesâ size and iconic precision across
retellings. Speakers gestured less frequently in stories retold to Old Addressees than New Addressees. Moreover, the
gestures they produced in stories retold to Old Addressees were smaller and less precise than those retold to New
Addressees, although these were attenuated over time as well. Consistent with our previous findings about speaking,
gesturing is guided by both speaker-based (cognitive) and addressee-based (communicative) constraints that affect
both planning and motoric execution. We discuss the implications for models of co-speech gesture production
Attenuation compensation technique and rainfall rate estimation using C-band dual polarization radar
The effectiveness of an attenuation correction procedure on the error structure of a C-band radar rainfall estimation is studied theoretically and by computer simulation. The iterative procedure to correct the radar observables
affected by attenuation is based on the best-fit relationships between the absolute and differential reflectivity and the specific absolute and differential attenuation. This paper evaluates this attenuation correction procedure by a computer simulation to value the rainfall rate estimation errors
The virtuous cycle of stakeholder engagement in developing a sustainability culture: Salcheto winery
Stakeholder engagement in sustainability represents a powerful driver for value creation. Drawing from stakeholder theory, this paper explores how a firm with a proactive sustainable behaviour engages stakeholders in developing innovation and creating value. A longitudinal, single case study of the Salcheto winery was carried out. Since the late 1990s, Salcheto has been at the forefront of wine eco-innovation and it has played a key role in the development of Montepulciano (Tuscany, Italy) as one of the first sustainable wine clusters worldwide. The development of a sustainable wine culture is one of the firm's various innovations. In doing so, the firm has had to face three challenges - identity creation, legitimization and enhancement - and has engaged its stakeholders through three specific mechanisms (adoption and development; co-creation and diffusion; exploitation and contamination). This virtuous cycle of stakeholder engagement has resulted in value creation at a firm, stakeholder and local level
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