Search results for "Data type"
showing 10 items of 1183 documents
A Hybrid Machine Learning and Knowledge Based Approach to Limit Combinatorial Explosion in Biodegradation Prediction
2016
One of the main tasks in chemical industry regarding the sustainability of a product is the prediction of its environmental fate, i.e., its degradation products and pathways. Current methods for the prediction of biodegradation products and pathways of organic environmental pollutants either do not take into account domain knowledge or do not provide probability estimates. In this chapter, we propose a hybrid knowledge-based and machine learning-based approach to overcome these limitations in the context of the University of Minnesota Pathway Prediction System (UM-PPS). The proposed solution performs relative reasoning in a machine learning framework, and obtains one probability estimate fo…
Integrated Mathematical Model of Proton Exchange Membrane Fuel Cell Stack (PEMFC) with Automotive Synchronous Electrical Power Drive
2008
In this work, the mathematical dynamical model of a PEMFC stack has been developed and implemented in Matlab environment. Lots of simulations have been executed in two different load conditions. Firstly with a resistive load and finally with a synchronous electrical power drive in automotive load conditions. The innovation in this field consists in the integration in PEMFC stack mathematical dynamic model of a synchronous electrical power drive one for automotive purposes. As regards the simulations with a synchronous electrical power drive, the complete mathematical model allows to evaluate the PEMFC stack performances and electrochemical efficiency. This represents a useful design tool.
Lay-up optimization for the hull of a racing sailing yacht
2001
Abstract Deformability and buckling load of yacht hulls with fiber reinforced plastic sandwich structure depend on the stack sequence of the skins. In this work an optimization of fiber directions of the laminae for a racing yacht is proposed. This procedure has been divided into three parts (i.e. material characterization, surface model definition, lay-up optimization). First of all a set of unidirectional specimens has been realized, by using the same fibers and matrix (carbon/epoxy) used for the hull as well as the same procedure and workers, in order to characterize the material according to American Society for Testing and Materials (ASTM) Standard D3039, employing strain gage techniqu…
A structured filter for Markovian switching systems
2014
In this work, a new methodology for the structuring of multiple model estimation schemas is developed. The proposed filter is applied to the estimation and detection of active mode in dynamic systems. The discrete-time Markovian switching systems represented by several linear models, associated with a particular operating mode, are studied. Therefore, the main idea of this work is the subdivision of the models set to some subsets in order to improve the detection and estimation performances. Each subset is associated with sub-estimators based on models of the subset. In order to compute the global estimate and subset probabilities, a global estimator is proposed. Theoretical developments ba…
Developing a Knowledge Base about the Technological Forces within the Asymmetric Incremental Forming Process
2015
Asymmetric single point incremental forming (ASPIF) has been recognized as a solution with potential in manufacturing small batches or single sheet metal parts. The approach presented in this paper presents the development of a knowledge base regarding the values of the technological force within the ASPIF process and the influence of some technological parameters such as feed, speed of the punch, thickness of the part and step, upon them. The method is based on the use of the information provided by the CNC machine sensors. Relationships between the torques developed by the drive motors on each axes and the technological forces will be set in order to refine the raw information displayed o…
Local Monitor Implementation for Decentralized Intrusion Detection in Secure Multi–Agent Systems
2007
This paper focuses on the detection of misbehav- ing agents within a group of mobile robots. A novel approach to automatically synthesize a decentralized Intrusion Detection System (IDS) as well as an efficient implementation of local monitors are presented. In our scenario, agents perform possi- bly different independent tasks, but cooperate to guarantee the entire system’s safety. Indeed, agents plan their next actions by following a set of logic rules which is shared among them. Such rules are decentralized, i.e. they depend only on configurations of neighboring agents. However, some agents may not be acting according to this cooperation protocol, due to spontaneous failure or tampering.…
An architecture Wi-fi and GPRS for efficient management of distribution electrical networks
2008
In this paper, a telecommunication infrastructure for faults management is proposed. The complete automation of the electrical energy distribution requires the implementation of suitable data transmission systems able to easily interface with microprocessor based systems and to handle large amount of data. In particular, reliability and speed of the data transmission system are required in the fault diagnosis and post-fault management procedures, in order to guarantee high quality standards. The proposed diagnostic system indeed works by means of a set of intercommunicating MV/LV dasiaintelligent substationspsila. In this paper, after a brief description of the fault diagnostic system, an o…
Finite Element Method Analysis of a Spur Gear with a Corrected Profile
2007
The difference between the stress value calculated by a two-dimensional finite element model of spur gears and those obtained by the rules in ISO 6336 was evaluated. Hertz theory, which provides information on the extension of the contact area and the maximum value of the contact pressure, was used to choose the dimensions of the elements. The mesh was created using the stress analytical solution relative to a model consisting of two cylinders in contact. Analogous optimization was executed for the mesh of the teeth feet; a mesh of 15 elements was considered optimum, because it minimized the difference to 0.5 per cent in the bending stress calculation. Stress values, obtained using the fin…
COMPARATIVE ANALYSIS OF RIGID AND FLEXIBLE STRUCTURES OF THE ECCENTRIC PRESSES
2007
Abstract The aim of this paper is to make a comparative study of the static behaviour of the eccentric presses, using the finite elements method, on the rigid structure and on the flexible structure, respectively. The finite elements modelling of the component elements of the presses are done in two ways: node by node link type (rigid structure) or using a linking element spring damper type (flexible structure). On these two structures there is successively applied a number of static analyses, in order to determine the strain of working area and the design of the stiffness graph.
New solutions for prefabricated secondary substations in the view of sustainability
2016
The secondary substations will assume an important role as “smart nodes” of the smart grid. So in few years there will be a widespread dissemination on the territory of this apparatus. Consequently, great care have to be taken not only on safety issues, but also on the constructive methodology, in order to determine low environmental impact and decommissioning cost. This paper focuses on innovative solutions for the realization of prefabricated secondary substations, in the direction of sustainability. Innovative layout and enclosure topologies have been here taken into account. In particular, by considering that the substation concrete box is, at the same time, uneconomical and with strong…