Search results for " interface"
showing 10 items of 1741 documents
Gigabit Ethernet backbones with active loops
2001
The current standard Ethernet switches are based on the Spanning Tree (ST) protocol. Their most important restriction is that they can not work when the topology has active loops. In fact, the ST protocol selects a tree from the real topology by blocking the links that are not involved in the tree. This restriction produces a network traffic unbalancing behavior saturating those link near the root switch while rest of links will be idle or with a very low utilization. This paper proposes a new transparent switch protocol for Gigabit Ethernet backbones that considerably improves the performance of current ones. The proposed protocol is named ALOR for Active Loops and Optimal Routing. ALOR pr…
Quantitative description of temperature induced self-aggregation thermograms determined by differential scanning calorimetry
2012
A novel thermodynamic approach for the description of differential scanning calorimetry (DSC) experiments on self-aggregating systems is derived and presented. The method is based on a mass action model where temperature dependence of aggregation numbers is considered. The validity of the model was confirmed by describing the aggregation behavior of poly(ethylene oxide)-poly(propylene oxide) block copolymers, which are well-known to exhibit a strong temperature dependence. The quantitative description of the thermograms could be performed without any discrepancy between calorimetric and van 't Hoff enthalpies, and moreover, the aggregation numbers obtained from the best fit of the DSC exper…
Potential determining salts in microemulsions: interfacial distribution and effect on the phase behavior.
2013
In this work we consider potential determining salts, also referred to as phase transfer agents for a future objective of electrochemistry at the oil-water interface in microemulsions. We have studied these salts, composed of a hydrophilic and a hydrophobic ion, in microemulsion stabilized by nonionic surfactants with an oligo ethylene oxide headgroup. NMR measurements show that the salts preferentially dissociate across the surfactant interface between the oil and water domains, and hence create a potential drop across the surfactant film, and back to back diffuse double layers in the oil and water phases. These observations are also supported by Poisson-Boltzmann calculations. This adsorp…
Ethylene and phenylene bridged polysilsesquioxanes functionalized by amine and thiol groups as adsorbents of volatile organic compounds
2007
Abstract Ethylene and phenylene bridged polysilsesquioxane xerogels having amine and thiol groups attached to the surface have been obtained by the sol–gel method from 1,2-bis(triethoxysilyl)ethane or 1,4-bis(triethoxysilyl)benzene and functionalized silanes in the presence of an ammonium fluoride catalyst in an ethanol solution. The synthesized samples have a porous structure (700–850 m2/g) and a high content of functional groups (1.4–1.9 mmol/g). The obtained porous bridged polysilsesquioxanes exhibit a considerable affinity for adsorbing several organic compounds (n-hexane, n-heptane, benzene, cyclohexane, acetonitrile and triethylamine) from the gas phase. The sample with an ethylene br…
DFT study on complete ethylene decomposition on flat and stepped Pd
2010
Abstract We applied density functional theory (DFT) calculations to study ethylidyne (CCH 3 ) adsorption and decomposition to C and H over flat and stepped Pd surfaces. Our calculations show that ethylidyne is the most stable molecule among all the possible dehydrogenation or decomposition residues of ethylene. We discuss various possible reaction pathways for ethylidyne decomposition and point out that the most probable one is via ethynyl (CCH) species suggested also by experimental observations. Our calculations indicate that the presence of steps modify the potential energy surface by increasing the binding of most of the species, and also lowering the activation barrier for several reac…
A Multimodal Guide for Virtual 3D Models of Cultural Heritage Artifacts
2008
The area of cultural heritage preservation and fruition has drawn an ever growing attention of artificial intelligence and human-computer interaction research in the last decades. The common aim is to develop systems that can interact with the user in a variety of modes and in the most natural way. In this paper, a multimodal guide for virtual 3D environment navigation is presented. The proposed system integrates X3D environment with a multimodal interface. The application scenario is to provide a visitor assistance and guidance during the visit of one of the halls in the historical Palazzo Steri, the headquarters of the University of Palermo.
An experimental study of dynamic behaviour of graphite polycarbonatediol polyurethane composites for protective coatings
2013
Segmented polycarbonatediol polyurethane (PUPH) has been synthesized and modified with different amounts of graphite conductive filler (from 0 to 50 wt%). Thermal and dynamical thermal analysis of the composites clearly indicates changes in the polyurethane relaxations upon addition of graphite. Broadband dielectric spectroscopy has been used to study the dielectric properties of the (PUPH) and one composite in the frequency range from 10−2 to 107 Hz and in the temperature window of −140 to 170 ◦C. Relaxation processes associated with different molecular motions and conductivity phenomena (Maxwell–Wagner–Sillars and electrode polarization) are discussed and related to the graphite content
A low-cost embedded IDS to monitor and prevent Man-in-the-Middle attacks on wired LAN environments
2007
A man-in-the-middle (MitM) attack is, in the scope of a LAN, a technique where an attacker is able to redirect all traffic between two hosts of that same LAN for packet sniffing or data manipulation, without the end hosts being aware of it. Usually these attacks exploit security flaws in the implementation of the ARP protocol at hosts. Up to now, detecting such attacks required setting up a machine with special-purpose software for this task. As an additional problem, few intrusion detection systems (IDS) are able to prevent MitM attacks. In this work we present a low-cost embedded IDS which, when plugged into a switch or hub, is able to detect and/or prevent MitM attacks automatically and …
DEMO: Unconventional WiFi-ZigBee communications without gateways
2014
Nowadays, the overcrowding of ISM bands is becoming an evident limitation for the performance and widespread usage of 802.11 and 802.15.4 technologies. In this demo, we prove that it is possible to opportunistically exploit the inter-technology interference between 802.11 and 802.15.4 to build an unconventional low-rate communication channel and signalling protocol, devised to improve the performance of each contending technology. Differently from previous solutions, inter-technology communications do not require the deployment of a gateway with two network interfaces, but can be activated (when needed) directly between two heterogeneous nodes, e.g. a WiFi node and a ZigBee node. This capab…
A user-friendly control system to easy reconfigure a manufacturing cell
2006
Generic manufacturing enterprises need to interact with an environment characterized by a strong competition. In order to react to the mutable requests of market, control systems should confer to the manufacturing system capabilities for easy modifiability, and this can be achieved by reducing the necessary time to reconfigure the existing system. Following this main requirement, this paper presents a user-friendly control system that pursues three operational goals: - Ability to easy re-program the sequence of operations of the manufacturing equipments of a manufacturing cell; - Reconfigurability of the system, by allowing to add/remove a new/existing component in/from the manufacturing ce…