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Number of results: 9
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Abstract

Finger vein biometric systems become increasingly more popular because they offer higher security comparing to other authentication solutions with respect to positive persons experience. Those systems operate on near infrared light (NIR) in wavelength range from around 700 to 1000 nm, however dedicated research to determine impact of NIR lighting on biometric system effectiveness has not been conducted and presented in the literature ever before. In this paper the study of correlation between wavelengths in NIR spectra and effectiveness of person identification in a biometric system is presented. To achieve that goal, a new model of image acquisition system allowing change of light wavelengths has been created and NIR finger vein dataset containing 11 556 images was established. Furthermore, this model was used to perform experimental work and proof that some NIR wavelengths better suit for vein patterns acquisition, allowing to increase the recognition effectiveness of finger vein biometric systems.

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Authors and Affiliations

M. Waluś
K. Bernacki
J. Konopacki
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Abstract

The paper indicates the significance of the problem of foundry processes parameters stability supervision and assessment. The parameters, which can be effectively tracked and analysed using dedicated computer systems for data acquisition and exploration (Acquisition and Data Mining systems, A&D systems) were pointed out. The state of research and methods of solving production problems with the help of computational intelligence systems (Computational Intelligence, CI) were characterised. The research part shows capabilities of an original A&DM system in the aspect of selected analyses of recorded data for cast defects (effect) forecast on the example of a chosen iron foundry. Implementation tests and analyses were performed based on selected assortments for grey and nodular cast iron grades (castings with 50 kg maximum weight, casting on automatic moulding lines for disposable green sand moulds). Validation tests results, applied methods and algorithms (the original system’s operation in real production conditions) confirmed the effectiveness of the assumptions and application of the methods described. Usability, as well as benefits of using A&DM systems in foundries are measurable and lead to stabilisation of production conditions in particular sections included in the area of use of these systems, and as a result to improvement of casting quality and reduction of defect number.

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Authors and Affiliations

R. Sika
Z. Ignaszak
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Abstract

The development of accurate computer control of a 3 MV Van de Graaff accelerator operation is described. The developed system comprises the accelerator turn-on and turn-off procedures during a normal run, which includes the setting of the terminal voltage, ion source light up, beam focusing and control of ion beam current and energy during operation. In addition, the computer monitors the vacuum and is able to make a detail register of the most important events during a normal run. The computer control system uses a LabVIEW application for interaction with the operator and an I/O board that interfaces the computer and the accelerator system. For everyday operating conditions the control implemented is able to turn-on and off the machine in about the same time as a specialized technician. In addition, today more users can make experiments in the accelerator without the help of a specialized operator, which in turns increases the number of hours during which the accelerator can be used.

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Authors and Affiliations

José Lopes
Francisco Alegria
Luís Redondo
Jorge Rocha
Eduardo Alves
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Abstract

A significant development of the foundry industry contributes to the creation of high reliability and operational strength castings so that they meet specific standards in accordance with customers’ needs. This technology, however, is inseparably connected with casting defects in finished products. Cast products are subject to various defects which are considered acceptable or not, which is conditioned by the alloy chemical composition and strength characteristics, that is, generally – qualities to be agreed between the foundry and the customer. It is the latter that led the authors to research on designing a tool enabling the most reliable possible assessment of the emerging casting defects, which after proper consultations can be repaired and the casting – sold. The paper presents an original tool named the Open Atlas of Defects (OAD), developed for the last few years to support the evaluation of cast iron defects using Non-Destructive Testing (NDT) casting defects analysis tools (DCC card – Demerit Control Chart, Pareto-Lorenz analysis and ABC analysis). The OAD tool structure was presented as an integral part of the original system module for acquisition and data mining (A&DM) in conjunction with the possibilities of using selected tools for defect analysis support on the example of cast iron casting.

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Authors and Affiliations

R. Sika
M. Rogalewicz
A. Kroma
Z. Ignaszak
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Abstract

The article presents an example of analysis of the influence of selected parameters deriving from data acquisition in foundries on the occurrence of Gas porosity defects (detected by Visual testing) in castings of ductile cast iron. The possibilities as well as related effectiveness of prediction of this kind of defects were assessed. The need to rationally limit the number of possible parameters affecting this kind of porosity was indicated. Authors also benefited from expert group's expertise in evaluating possible causes associated with the creation of the aforementioned defect. A ranking of these parameters was created and their impact on the occurrence of the defect was determined. The classic statistical tools were used. The possibility of unexpected links between parameters in case of uncritical use of these typical statistical tools was indicated. It was emphasized also that the acquisition realized in production conditions must be subject to a specific procedure ordering chronology and frequency of data measurements as well improving the casting quality control. Failure to meet these conditions will significantly affect the difficulties in implementing and correcting analysis results, from which INput/OUTput data is expected to be the basis for modelling for quality control.

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Authors and Affiliations

Z. Ignaszak
R. Sika
M. Rogalewicz
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Abstract

Electronic voltage transformers (EVT) and electronic current transformers (ECT) are important instruments in a digital substation. For simple, rapid and convenient development, the paper proposed an on-site calibration system for electronic instrument transformers based on LabVIEW. In the system, analog signal sampling precision and dynamic range are guaranteed by the Agilent 3458A digital multimeter, and data synchronization is also achieved based on a self-developed PCI synchronization card. To improve the measurement accuracy, an error correction algorithm based on the Hanning window interpolation FFT has good suppression of frequency fluctuation and inter-harmonics interference. The human-computer interface and analysis algorithm are designed based on LabVIEW, and the adaptive communication technology is designed based on IEC61850 9-1/2. The calibration system can take into account pairs of digital output and analog output of the electronic voltage/current transformer calibration. The results of system tests show that the calibration system can meet the requirements of 0.2 class calibration accuracy, and the actual type test and on-site calibration also show that the system is easy to operate with convenience and satisfactory stability.

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Authors and Affiliations

Ming Zhang
Kaicheng Li
Jun Wang
Shunfan He
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Abstract

The paper undertakes an important topic of evaluation of effectiveness of SCADA (Supervisory Control and Data Acquisition) systems,

used for monitoring and control of selected processing parameters of classic green sands used in foundry. Main focus was put on process

studies of properties of so-called 1st generation molding sands in the respect of their preparation process. Possible methods of control of

this processing are presented, with consideration of application of fresh raw materials, return sand (regenerate) and water. The studies

conducted in one of European foundries were aimed at pointing out how much application of new, automated plant of sand processing

incorporating the SCADA systems allows stabilizing results of measurement of selected sand parameters after its mixing. The studies

concerned two comparative periods of time, before an implementation of the automated devices for green sands processing (ASMS -

Automatic Sand Measurement System and MCM – Main Control Module) and after the implementation. Results of measurement of

selected sand properties after implementation of the ASMS were also evaluated and compared with testing studies conducted periodically

in laboratory.

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Authors and Affiliations

Z. Ignaszak
J. Kozłowski
M. Perzyk
R. Sika
A. Kochański
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Abstract

In this paper, we propose a concept of a continuous-time filter of constant component that exhibits a very short response in the time domain if compared to the traditional time-invariant filter. The improvement of the filter dynamics was achieved as a result of the time-varying parameters which were introduced to the filter structure. Such a designed filter is then applied in a system which switches many distorted signals which should be filtered as fast as possible. The paper is of review nature and presents both a theoretical background of the proposed filter and the results of simulations.

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Authors and Affiliations

Jacek Piskorowski
Roman Kaszyński
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Abstract

An embedded time interval data acquisition system (DAS) is developed for zero power reactor (ZPR) noise experiments. The system is capable of measuring the correlation or probability distribution of a random process. The design is totally implemented on a single Field Programmable Gate Array (FPGA). The architecture is tested on different FPGA platforms with different speed grades and hardware resources. Generic experimental values for time resolution and inter-event dead time of the system are 2.22 ns and 6.67 ns respectively. The DAS can record around 48-bit x 790 kS/s utilizing its built-in fast memory. The system can measure very long time intervals due to its 48-bit timing structure design. As the architecture can work on a typical FPGA, this is a low cost experimental tool and needs little time to be established. In addition, revisions are easily possible through its reprogramming capability. The performance of the system is checked and verified experimentally.

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Authors and Affiliations

Mohammad Arkani
Hossein Khalafi
Naser Vosoughi

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