Search results for "layer"

CFD prediction of scalar transport in thin channels for reverse electrodialysis

2014

Reverse ElectroDialysis (RED) is a very promising technology allowing the electrochemical potential difference of a salinity gradient to be directly converted into electric energy. The fluid dynamics optimization of the thin channels used in RED is still an open problem. The present preliminary work focuses on the Computational Fluid Dynamics (CFD) simulation of the flow and concentration fields in these channels. In particular three different configurations were investigated: a channel unprovided with a spacer (empty channel) and two channels filled with spacers, one made of overlapped filaments the other of woven filaments. The transport of two passive scalars, representative of the ions …

Earthing System's Design in presence of non-uniform soil

2007

The Authors propose a practical approach for facing the problem of the design of the earthing systems in two-layer soils. The approach is based on the calculation of an equivalent resistivity of the non-uniform soil through which the designer can treat this one as it was uniform. The purpose of the Authors is to provide an innovative simple method and some easy-to-use graphs for an easy earthing systems’ design in two-layer soils.

An energy analysis of IEEE 802.15.6 scheduled access modes

2010

Body Area Networks (BANs) are an emerging area of wireless personal communications. The IEEE 802.15.6 working group aims to develop a communications standard optimised for low power devices operating on, in or around the human body. IEEE 802.15.6 specifically targets low power medical application areas. The IEEE 802.15.6 draft defines two main channel access modes; contention based and contention free. This paper examines the energy lifetime performance of contention free access and in particular of periodic scheduled allocations. This paper presents an overview of the IEEE 802.15.6 and an analytical model for estimating the device lifetime. The analysis determines the maximum device lifeti…

Architectures and Protocols for Flexible Physical Layers in Wireless Networks

Emerging wireless technologies are characterized by an increasing level of flexibility and programmability, not only in terms of core network functionalities, with the consolidated paradigms of software-defined-networks and function virtualization, but also in terms of radio access functionalities. Although the concept of software-defined PHY and MAC protocols is not new, exploiting flexibility at the lower layers of the protocol stack is not an easy task, because of complexity and performance constraints. Indeed, dealing with software-defined implementations of the radio implies managing complex software routines, often tightly inter-dependent and difficult to reuse, and poses some perform…

Understanding the Environment through Wireless Sensor Networks

2007

This paper presents a new cognitive architecture for extracting meaningful, high-level information from the environment, starting from the raw data collected by a Wireless Sensor Network. The proposed framework is capable of building rich internal representation of the sensed environment by means of intelligent data processing and correlation. Furthermore, our approach aims at integrating the connectionist, data-driven model with the symbolic one, that uses a high-level knowledge about the domain to drive the environment interpretation. To this aim, the framework exploits the notion of conceptual spaces, adopting a conceptual layer between the subsymbolic one, that processes sensory data, a…

Sub-Symbolic Semantic Layer in Cyc for Intuitive Chat-Bots

2007

The work presented in this paper aims to combine Latent Semantic Analysis methodology, common sense and traditional knowledge representation in order to improve the dialogue capabilities of a conversational agent. In our approach the agent brain is characterized by two areas: a "rational area", composed by a structured, rule-based knowledge base, and an "associative area", obtained through a data-driven semantic space. Concepts are mapped in this space and their mutual geometric distance is related to their conceptual similarity. The geometric distance between concepts implicitly defines a sub-symbolic relationship net, which can be seen as a new "subsymbolic semantic layer" automatically a…

Sub-Symbolic Knowledge Representation for Evocative Chat-Bots

2008

A sub-symbolic knowledge representation oriented to the enhancement of chat bot interaction is proposed. The result of the technique is the introduction of a semantic sub-symbolic layer to a traditional ontology-based knowledge representation. This layer is obtained mapping the ontology concepts into a semantic space built through Latent Semantic Analysis (LSA) technique and it is embedded into a conversational agent. This choice leads to a chat-bot with “evocative” capabilities whose knowledge representation framework is composed of two areas: the rational and the evocative one. As a standard ontology we have chosen the well-founded WordNet lexical dictionary, while as chat-bot the ALICE a…

Enabling Technologies on Hybrid Camera Networks for Behavioral Analysis of Unattended Indoor Environments and Their Surroundings

2008

This paper presents a layered network architecture and the enabling technologies for accomplishing vision-based behavioral analysis of unattended environments. Specifically the vision network covers both the attended environment and its surroundings by means of multi-modal cameras. The layer overlooking at the surroundings is laid outdoor and tracks people, monitoring entrance/exit points. It recovers the geometry of the site under surveillance and communicates people positions to a higher level layer. The layer monitoring the unattended environment undertakes similar goals, with the addition of maintaining a global mosaic of the observed scene for further understanding. Moreover, it merges …

Enabling Multimodal Interaction in XPL – the eXtensible Presentation Language

2007

This paper introduces the multimodal extension of the eXtensible Presentation architecture and Language (XPL), a framework aimed at streamlining multi-channel interface design process and enabling full component reuse. XPL incorporates a presentation language based on design pattern paradigm, which supplies a clear distinction between the presentation layer and the corresponding programming logic, promoting contents aggregation and a variety of event handlers described without relying on a (procedural) scripting language. In this paper, the design pattern concept is extended to voice-based interaction, and two verbal design pattern (VeDP) are introduced along to their visual counterparts. T…

Learning Path Generation by Domain Ontology Transformation

2005

An approach to automated learning path generation inside a domain ontology supporting a web tutoring system is presented. Even if a terminological ontology definition is needed in real systems to enable reasoning and/or planning techniques, and to take into account the modern learning theories, the task to apply a planner to such an ontology is very hard because the definition of actions along with their preconditions and effects has to take into account the semantics of the relations among concepts, and it results in building an ontology of learning. The proposed methodology is inspired to the Knowledge Space Theory, and proposes some heuristics to transform the original ontology in a weig…