1,720,975 research outputs found
An Experimental Evaluation on Using TDMA over 802.11 MAC for Wireless Networked Control
No full textThe recent interest for Wireless Networked Control Systems has boosted new research activities on real-time 802.11-based communications. In fact, due to their versatility, wireless LANs can be exploited as infrastructure in this kind of control systems, but changes to channel access techniques are required. To this aim, we propose a novel experimental implementation of a TDMA scheme over 802.11 MAC, based on the hard real-time networking framework RTnet and on the Xenomai real-time task scheduler. Preliminary results have shown that, using the proposed approach, transmission delays smaller than 10 ms and packet loss rates smaller than 0.5% can be achieved
Membrane- and cell wall-associated heat shock proteins in two genotypes of barley seedlings
No full textThe heat-shock (HS) response of two genotypes (cv. Onice winter type, and cv. Georgie, spring type) of barley (Hordeum vulgare L.) was compared. Protein synthesis was markedly reduced in cv. Onice was higher than in cv. Georgie. The pattern of cytosolic, membrane and cell wall HSPs was analysed by SDS-PAGE in coleoptiles and roots of the two genotypes. Differences and similarities in coleoptiles and roots of the same genotype and between the two genotypes were observed. In roots of the genotype Onice, LMW and HMW HSPs isolated from the cytosol, membranes and cell walls were resolved into a diverse array of polypeptides by two-dimensional gel electrophoresis. Present results confirm the de novo synthesis of cytosolic and membrane HSPs, and demonstrate, for the first time, their presence in cell walls
Toward Wireless Networked Control Systems: an Experimental Study on Real-time Communications in 802.11 WLANs
No full textNetworked Control Systems (NCSs) exploit a packet switching network to fulfill complex control tasks without cumbersome point-to-point wiring infrastructures. But their performances are greatly influenced by time-varying packet delays and losses due to the communication system. As a consequence, Real Time Operating Systems are usually employed at NCS nodes to timely serve events scheduled by control applications. So far NCS issues have been mainly investigated assuming a wired network infrastructure. Anyway the trend is toward wireless communications. For these reasons, this paper proposes a real-time communication architecture based on the leading wireless 802.11 technology and on the real-time networking framework RTnet. The QoS offered by the proposed system, in terms of packet loss ratio and end-to-end delay, has been experimentally evaluated by varying protocol parameters. Results show that a proper tuning of system parameters can ensure robust real-time wireless communications. Thus, the present work can be considered an important step toward the design of a Wireless Networked Control System
SUPERCRITICAL CO(2) EXTRACTED TOMATO OLEORESINS ENHANCE GAP JUNCTION INTERCELLULAR COMMUNICATIONS AND RECOVER FROM MERCURY CHLORIDE INHIBITION IN KERATINOCYTES
No full textA nutritionally relevant phytochemical such as lycopene, found in tomatoes and other fruits, has
been proposed to have health-promoting effects by modulating hormonal and immune systems,
metabolic pathways, and gap junction intercellular communication (GJIC). This work analyzes
lycopene extracts, obtained from tomato and tomato added with grape seeds by using a safe
and environmentally friendly extraction process, based on supercritical carbon dioxide technology
(S-CO2). Analysis of the innovative S-CO2-extracted oleoresins showed peculiar chemical composition
with high lycopene concentration and the presence of other carotenoids, lipids, and phenol
compounds. The oleoresins showed a higher in vitro antioxidant activity compared with pure
lycopene and β-carotene and the remarkable ability to enhance the GJIC and to increase cx43
expression in keratinocytes. The oleoresins, (0.9 μM lycopene), were also able to overcome, completely,
the GJIC inhibition induced by 10 nM HgCl2, mercury(II) chloride, suggesting a possible
action mechanism
A Software-Defined Radio implementation of an 802.11 OFDM Physical Layer transceiver
No full textThis work presents our effort in developing a complete, real-time, Software-Defined Radio implementation of an OFDM transceiver, compliant with the IEEE 802.11 Physical Layer specifications. All the baseband components in both the transmitter and the receiver are implemented with fast software functions, running on a General Purpose CPU. Real-time operation is achieved on a modern CPU by means of extensive code optimization, mostly using the SIMD instruction sets which are widely available on almost every modern CPU
A telecommunications framework for real-time monitoring of dangerous goods transport
No full textMonitoring and tracking of fleets can represent a great improvement in security and safety when transporting hazardous goods by road. In this paper we propose a complete monitoring and tracking solution for truck fleets, which is able to check at the same time the position and the mechanical status of the vehicle, as well as the conditions in the cargo bay. The system exploits battery-powered environmental sensors (temperature, humidity, pressure, gas concentration and ionising radiation levels), connected by a ZigBee-based Wireless Sensor Network. This approach guarantees flexibility, ease of deployment and low power consumption. Collected data is then sent from the vehicle to a remote server via a GPRS link. The GPS positioning system is integrated by the use of an Inertial Navigation System, which guarantees a precise estimate of the position also when the GPS signal is weak or temporarily lost. The proposed solution has been deployed in a real environment, and some performance evaluation tests have been carried out
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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