Search results for "Processing"
showing 10 items of 8572 documents
Consensus-Based Distributed State Estimation of Biofilm in Reverse Osmosis Membranes by WSNs
2017
The appearance of biofilm has become a serious problem in many reverse osmosis based systems such as the ones found in water treatment and desalination plants. In these systems, the use of traditional techniques such as pretreatment or dozing biocides are not effective when the biofilm reaches an irreversible attachment phase. In this work, we present a framework for the use of a WSN as an estimator of the biofilm evolution in a reverse osmosis membrane so that effective solutions can be applied before the irreversible phase is attained. This design is addressed in a complete distributed and decentralized fashion, and subject to realistic constraints where cooperation between nodes is perfo…
Learning of Cooperative Behaviour in Robot Populations
2016
This paper addresses convergence and equilibrium properties of game theoretic learning algorithms in robot populations using simple and broadly applicable reward/cost models of cooperation between robotic agents. New models for robot cooperation are proposed by combining regret based learning methods and network evolution models. Results of mean-field game theory are employed in order to show the asymptotic second moment boundedness in the variation of cooperative behaviour. The behaviour of the proposed models are tested in simulation results, which are based on sample networks and a single lane traffic flow case study.
Smart factory in the context of 4th industrial revolution: challenges and opportunities for Romania
2017
Manufacturing companies, independent of operation sector and size, must be able to produce lot size one products, just-in-time at a competitive cost. Coping with this high adaptability and short reaction times proves to be very challenging. New approaches must be taken into consideration for designing modular, intelligent and cooperative production systems which are easy to integrate with the entire factory. The coined term for this network of intelligent interacting artefacts system is cyber-physical systems (CPS). CPS is often used in the context of Industry 4.0 – or what many consider the forth industrial revolution. The paper presents an overview of key technological and social requirem…
Finite-time stability and stabilisation for a class of nonlinear systems with time-varying delay
2014
This paper is concerned with the problems of finite-time stability FTS and finite-time stabilisation for a class of nonlinear systems with time-varying delay, which can be represented by Takagi–Sugeno fuzzy system. Some new delay-dependent FTS conditions are provided and applied to the design problem of finite-time fuzzy controllers. First, based on an integral inequality and a fuzzy Lyapunov–Krasovskii functional, a delay-dependent FTS criterion is proposed for open-loop fuzzy system by introducing some free fuzzy weighting matrices, which are less conservative than other existing ones. Then, the parallel distributed compensation controller is designed to ensure FTS of the time-delay fuzzy…
Influence of friction stir processing conditions on the manufacturing of Al-Mg-Zn-Cu alloy/boron carbide surface composite
2018
Abstract Surface metal matrix composites were synthesized via friction stir processing (FSP) on the surface of aluminium alloy 7075 (AA 7075) sheets by incorporating B4C particles (B4CP). The influence of tool rotational speeds, powder particle sizes, and change in tool travel direction between FSP passes on particle distribution and resulting properties were studied in detail. Change in tool travel direction, decreased tool rotation speed and fine B4C particles enhanced B4CP distribution and wear properties thereof. Wear resistance of composites were doubled on account of the B4CP distribution and resultant several strengthening mechanisms.
Enhancement of mechanical properties of FSWed AA7075 lap joints through in-situ fabrication of MMC
2017
Abstract Friction Stir Processing (FSP) has been demonstrated feasible to create local Metal Matrix Composites (MMCs) in light alloys matrix. In this research, local MMCs were produced contextually to the weld using Friction Stir Welding (FSW). SiC particles were added to AA7075 lap joints by creating a proper groove on the top surface of the bottom sheet. Different welds were produced with increasing number of tool passes. The effect of the multiple passes was investigated through shear tests, macro and micro observations, average grain size and microhardness measurements. The welded joints were compared to a reference weld produced with no reinforcements. It was found that poor mixing bet…
Image Enhancement Algorithm for Optical Microstructural Characterization of Shape Memory TiNi Friction Stir Processed
2017
Abstract A key topic regarding TiNi alloys concerns the possibility to attain junctions that preserve the shape memory properties of material. Experimental tests, previously performed on TiNi sheet friction stir processed, have highlighted the need to develop an appropriate image analysis method to quantify the various phases percentages present in the characteristics zones of Friction Stir Welding process. A proper Image Processing procedure has been performed in order to quantify the amount of the martensitic phase and to detect its morphology modification along to the processed region. Particularly each micrographic image, firstly, has been denoised using the 2D Wavelet transform techniq…
Introducing a Fuzzy-Pattern Operator in Fuzzy Time Series
2017
In this paper we introduce a fuzzy pattern operator and propose a new weighting fuzzy time series strategy for generating accurate ex-post forecasts. A decision support system is built for managing the weights of the information provided by the historical data, under a fuzzy time series framework. Our procedure analyzes the historical performance of the time series using different experiments, and it classifies the characteristics of the series through a fuzzy operator, providing a trapezoidal fuzzy number as one-step ahead forecast. We also present some numerical results related to the predictive performance of our procedure with time series of financial data sets.
Reliable diagnostics using wireless sensor networks
2019
International audience; Monitoring activities in industry may require the use of wireless sensor networks, for instance due to difficult access or hostile environment. But it is well known that this type of networks has various limitations like the amount of disposable energy. Indeed, once a sensor node exhausts its resources, it will be dropped from the network, stopping so to forward information about maybe relevant features towards the sink. This will result in broken links and data loss which impacts the diagnostic accuracy at the sink level. It is therefore important to keep the network's monitoring service as long as possible by preserving the energy held by the nodes. As packet trans…
Central catadioptric image processing with geodesic metric
2011
International audience; Because of the distortions produced by the insertion of a mirror, catadioptric images cannot be processed similarly to classical perspective images. Now, although the equivalence between such images and spherical images is well known, the use of spherical harmonic analysis often leads to image processing methods which are more difficult to implement. In this paper, we propose to define catadioptric image processing from the geodesic metric on the unitary sphere. We show that this definition allows to adapt very simply classical image processing methods. We focus more particularly on image gradient estimation, interest point detection, and matching. More generally, th…