Search results for " processing"
showing 10 items of 7549 documents
An Object-Oriented Approach to Discrete-Event Simulation Applied to Underground Railway Systems
1999
This paper describes the implementation of an object-oriented simulator that supports the determination of timetables and the design of on-line control policies for underground rail way systems. The simulator has been developed on the basis of a new approach to object- oriented modelling. Such an approach has been used to design a development tool that supports the generation of simulation codes and is able to automatically define the skeleton of a code.
A GRASP algorithm for the container stowage slot planning problem
2016
This work presents a generalization of the Slot Planning Problem which raises when the liner shipping industry needs to plan the placement of containers within a vessel (stowage planning). State-of-the-art stowage planning relies on a heuristic decomposition where containers are first distributed in clusters along the vessel. For each of those clusters a specific position for each container must be found. Compared to previous studies, we have introduced two new features: the explicit handling of rolled out containers and the inclusion of separations rules for dangerous cargo. We present a novel integer programming formulation and a Greedy Randomized Adaptive Search Procedure (GRASP) to solv…
Cloudy with a Chance of Fuzzy: Building a Multicriteria Uncertainty Model for Construction Project Delivery Selection
2017
AbstractThe process of choosing a project delivery method is infused with cognitive uncertainties associated with the decision maker. Fuzzy uncertainties arise because of imprecise understanding and subsequent representation of these uncertainties by the decision maker, whereas random uncertainties arise from variance of these imprecisions. Since there are no well-defined rules for spontaneous decisions, in order to be consistently confident in the appropriateness of the chosen delivery method, a structured approach incorporating uncertainty is required. Previously unanswered questions such as (1) what are the sources of uncertainty in project delivery decisions, (2) how do decision makers …
Determination of Technological Forces in the Incremental Forming Process
2013
The paper presents a joint theoretical and experimental approach to determine the technological forces within the asymmetric single point incremental forming ASPIF process, based upon a theoretical model, image processing and data acquisition. The first step of this approach was to develop a theoretical model of the forces within the process, based upon the model of a mechanical feed drive of a CNC milling machine. By means of this model, relationships between the resistant torque at the motor spindle level and the technological force on the movement axis could be determined. Using an image processing method, which allowed the user to extract information within the machines operator panel a…
Spatial and thermal measurements using thermography CCD during HF soldering of metallic tubes
2002
High frequency soldering allows high production speed, contactless heating and good quality of the weld. The speed limit of soldering is principally imposed by a good drive of the metal in the profiling machine. To control a HF soldering process, the authors propose a new method and approach which consists in controlling the temperature with a thermal image acquisition system developed in their laboratory. Their computer vision, described in this paper, is based on CCD thermography. This technology brings many advantages and tools in the measurement of thermal and spatial parameters. In fact, high spatial (800/spl times/600 pixels) and temporal resolutions, good relative thermal resolution …
Feasibility issues in static output-feedback controller design with application to structural vibration control
2014
Recent results in output-feedback controller design make possible an efficient computation of static output-feedback controllers by solving a single-step LMI optimization problem. This new design strategy is based on a simple transformation of variables, and it has been applied in the field of vibration control of large structures with positive results. There are, however, some feasibility problems that can compromise the effectiveness and applicability of the new approach. In this paper, we present some relevant properties of the variable transformations that allow devising an effective procedure to deal with these feasibility issues. The proposed procedure is applied in designing a static…
A DAQ-based sampling wattmeter for IEEE Std. 1459-2010 powers measurements. Uncertainty evaluation in nonsinusoidal conditions
2015
Abstract This paper presents the evaluation of the metrological performances of a DAQ-based sampling wattmeter (DAQ-SW) for the measurement of IEEE Std. 1459-2010 power quantities in non-sinusoidal conditions. The instrument makes use of two commercial data acquisition (DAQ) boards, a non-inductive current shunt, a personal computer and a commercial software for data processing. Starting from the results of an experimental characterization of the two instrument channels with non-sinusoidal voltages and currents and a correlation analysis, the combined standard uncertainties of IEEE Std. 1459-2010 quantities are evaluated, following the approach of the ISO Guide to the Expression of Uncertai…
Study of the Audio Susceptibility in Parallel Power Processing With a High-Power Topology
2009
In this paper, the audio susceptibility characteristic of a high-efficiency nonisolated topology that processes only a part of the total power delivery is analyzed. Since the proposed topology presents a direct path from input to output, the effect of the input voltage ripple at the output voltage has been studied. The effect on the audio susceptibility of the values and disposition of the components and the effect of their parasitic elements must be taken into account. Due to this study, the analytical expression of the audio susceptibility and the design criteria to improve it have been obtained.
A portable instrument for the location and identification of defects generating PD
2011
A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…
Computer aided photoelasticity by an optimum phase stepping method
2002
In this paper an automated photoelastic method based on the phase stepping technique is described. It provides full-field maps of the isoclinic parameter and the relative retardation. The technique is based on processing six images of a photoelastic specimen acquired using plane and circularly polarized light. The number of acquisitions and the type of polariscope used in this approach have been chosen with the aim at reducing the influence of quarter wave plate errors and obtaining raw photoelastic data in a periodic form suitable for easy applications of automatic unwrapping routines.