Search results

1 – 10 of 14
To view the access options for this content please click here
Article
Publication date: 3 April 2017

Izabela Kowalik, Lidia Danik and Tomasz Sikora

The purpose of this paper is to develop the international entrepreneurship theory, by examining the entrepreneurial characteristics of international new venture (INV…

Abstract

Purpose

The purpose of this paper is to develop the international entrepreneurship theory, by examining the entrepreneurial characteristics of international new venture (INV) originating in Poland. Furthermore, it is assessed in the study whether these characteristics relate to the performance of INVs, considering the role of the age of the company.

Design/methodology/approach

The data were collected via a CATI survey of 105 Polish small- and medium-sized enterprises (SMEs), conforming to the early internationalization criteria, and 128 gradually internationalized SMEs. Student’s t-tests, correlation and, regression analysis were applied for group comparisons and relationship testing.

Findings

The Polish INVs are characterized by higher innovativeness and risk propensity than gradual exporters. Moreover, medium-strength correlations between entrepreneurial orientation (EO) elements and performance were found. The regression analysis proved that new product introduction, risk taking, and experience influence INV performance.

Research limitations/implications

The sample includes Polish SMEs from one sector. Moreover, most of the analyzed companies admitted being successful abroad, which may have influenced the study results.

Practical implications

Fast launching of new products and product development are important for quick expansion. A conciliatory approach to competitors is associated with better performance. Regarding the policy makers, the development of “breakthrough innovations” might not be as important as assisting the INVs in product launches.

Originality/value

An under-researched topic of EO of SMEs from a post-transformation market and its relationships with performance is explored. Moreover, the correlation of the company’s age and experience with success is studied.

Details

Baltic Journal of Management, vol. 12 no. 2
Type: Research Article
ISSN: 1746-5265

Keywords

To view the access options for this content please click here
Article
Publication date: 8 October 2018

Tomasz Rymarczyk, Jan Sikora and Paweł Tchórzewski

The paper aims to present an innovative solution for evaluation study of the dampness level of walls and historical buildings.

Abstract

Purpose

The paper aims to present an innovative solution for evaluation study of the dampness level of walls and historical buildings.

Design/methodology/approach

Electrical tomography enables one to obtain a distribution pattern of wall dampness. The application of modern tomographic techniques in conjunction with topological algorithms will allow one to perform very accurate spatial assessment of the dampness levels of buildings. The proposed application uses the total variation, Gauss–Newton and level set method to solve the inverse problem in electrical tomography.

Findings

Research shows that electrical tomography can provide effective results in damp buildings. This method can provide 2D/3D moisture distribution pattern.

Research limitations/implications

The impact of this technique will be limited to inspection of the facility after floods or assessment of historical buildings.

Practical implications

The presented method could eventually lead to a much more effective evaluation of moisture in the walls.

Social implications

The solution has commercial potential and could result in more cost-effective monitoring of historical buildings, which have an economic impact on society.

Originality/value

The authors propose a system for imaging spatial moistness of walls and historic buildings based on electrical tomography and consisting of a measuring device, sensors and image reconstruction algorithms.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 1 January 1994

Ryszard Sikora, Tomasz Chady, Mieczyslaw Komorowski and Marek Ziółkowski

Development in microcomputer systems has led to their use for a three‐dimensional magnetic field calculation. It caused a great progress in numerical methods used for a…

Abstract

Development in microcomputer systems has led to their use for a three‐dimensional magnetic field calculation. It caused a great progress in numerical methods used for a magnetic field analysis in electric machines and devices. Determination of the calculations quality may be achieved by comparing with the measurements. For this purpose real objects or simplified models can be used.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 1
Type: Research Article
ISSN: 0332-1649

To view the access options for this content please click here
Article
Publication date: 2 January 2009

Tomasz Grzywacz, Jan Sikora and Stefan Wójtowicz

The purpose of this paper is to introduce a method for increasing imaging quality in impedance tomography. The paper presents an optical method of shape virtualization…

Abstract

Purpose

The purpose of this paper is to introduce a method for increasing imaging quality in impedance tomography. The paper presents an optical method of shape virtualization, processing algorithm draft and results of virtualization for sample objects.

Design/methodology/approach

In impedance tomography the image reconstruction algorithms must yield accurate images of impedance changes. One of the keys to producing an accurate reconstructed image is the inclusion of prior information regarding the physical geometry of the object. When the object under investigation is filled with transparent medium, optical methods can provide information about its interior and estimate the shape of non‐transparent interjections. Computer graphics methods (e.g. ray tracing) can be used to simulate propagation of the light transmitted along straight lines within the object, and thus yield geometric data to better imaging. The process of setting up boundary conditions is then supplied with additional information about interior of the object, which can significantly improve solution of the forward problem in impedance tomography.

Findings

The visibility matrix includes information about the interior of the object. However, the information is incomplete since the scanning is done along one axis. In order to obtain all remaining data, scanning along three axes is required. On the basis of the visibility matrix, the shape and volume of the non‐transparent interjections are recovered and then estimated.

Originality/value

The biggest novelty is indeed the combination of methods used in optical tomography with those in impedance tomography.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 28 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 3 May 2013

Przemyslaw Lopato, Tomasz Chady, Ryszard Sikora, Stanislaw Gratkowski and Marcin Ziolkowski

The purpose of this paper is to describe the full‐wave modelling of pulsed terahertz systems utilized in non‐destructive testing.

Abstract

Purpose

The purpose of this paper is to describe the full‐wave modelling of pulsed terahertz systems utilized in non‐destructive testing.

Design/methodology/approach

At the outset, some basic information on the terahertz NDT are outlined and then, general remarks on its numerical modelling are presented. Frequency domain FEM and time domain FDTD analysis is carried out. Finally comparison of computed and measured signals is shown in order to prove numerical analysis correctness.

Findings

It is possible to model in a relatively simple way a terahertz system for nondestructive evaluation of dielectric materials. In contrast to other published work, the entire measuring setup is modelled, including photoconductive antenna with hemispherical lens, focusing lens and evaluated material with exemplary defect.

Originality/value

This paper gives a description of the terahertz non‐destructive testing system with comparison of simulated and measured results.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 4 July 2016

Tomasz Chady, Ryszard Sikora, Mariusz Szwagiel, Bogdan Grzywacz, Leszek Misztal, Pawel Waszczuk, Michal Szydlowski and Barbara Szymanik

The purpose of this paper is to describe a multisource system for nondestructive inspection of welded elements exploited in aircraft industry developed in West Pomeranian…

Abstract

Purpose

The purpose of this paper is to describe a multisource system for nondestructive inspection of welded elements exploited in aircraft industry developed in West Pomeranian University of Technology, Szczecin in the frame of CASELOT project. The system task is to support the operator in flaws identification of welded aircraft elements using data obtained from X-ray inspection and 3D triangulation laser scanners.

Design/methodology/approach

For proper defects detection a set of special processing algorithms were developed. For easier system exploitation and integration of all components a user friendly interface in LabVIEW environment was designed.

Findings

It is possible to create the fully independent, intelligent system for welds’ flaws detection. This kind of technology might be crucial in further development of aircraft industry.

Originality/value

In this paper a number of innovative solutions (new algorithms, algorithms’ combinations) for defects’ detection in welds are presented. All of these solutions are the basis of presented complete system. One of the main original solution is a combination of the systems based on 3D triangulation laser scanner and X-ray testing.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 31 December 2020

Tomasz Rymarczyk, Konrad Kania, Michał Gołąbek, Jan Sikora, Michał Maj and Przemysław Adamkiewicz

The purpose of this study is to develop a reconstruction and measurement system for data analysis using ultrasonic transmission tomography. The problem of reconstruction…

Abstract

Purpose

The purpose of this study is to develop a reconstruction and measurement system for data analysis using ultrasonic transmission tomography. The problem of reconstruction from the projection is encountered in practical implementation, which consists in reconstructing an image that is an estimation of an unknown object from a finite set of projection data. Reconstructive algorithms used in transmission tomography are based on linear mathematical models, which makes it necessary to process non-linear data into estimates for a finite number of projections. The application of transformation methods requires building a mathematical model in which the projection data forming the known and unknown quantities are functions with arguments from a continuous set of real numbers, determining the function describing the unknown quantities sought in the form of inverse relation and adapting it to operate on discrete and noisy data. This was done by designing a tomographic device and proprietary algorithms capable of reconstructing two-dimensional images regardless of the size, shape, location or number of inclusions hidden in the examined object.

Design/methodology/approach

The application consists of a device and measuring sensors, as well as proprietary algorithms for image reconstruction. Ultrasonic transmission tomography makes it possible to analyse processes occurring in an object without interfering with the examined object. The proposed solution uses algorithms based on ray integration, the Fermat principle and deterministic methods. Two applications were developed, one based on C and implemented on the embedded device, while the other application was made in Matlab.

Findings

Research shows that ultrasonic transmission tomography provides an effective analysis of tested objects in closed tanks.

Research limitations/implications

In the presented technique, the use of ultrasonic absorption wave has been limited. Nevertheless, the effectiveness of such a solution has been confirmed.

Practical implications

The presented solution can be used for research and monitoring of technological processes.

Originality/value

Author’s tomographic system consisting of a measuring system and image reconstruction algorithms.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 40 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 2 January 2018

Tomasz Rudnicki, Andrzej Sikora, Robert Czerwinski and Tadeusz Glinka

This paper aims to present the impact of Pulse Width Modulation (PWM) control frequency for specific Permanent Magnet Synchronous Motors (PMSMs) on the efficiency of the…

Abstract

Purpose

This paper aims to present the impact of Pulse Width Modulation (PWM) control frequency for specific Permanent Magnet Synchronous Motors (PMSMs) on the efficiency of the entire driving unit. Examinations were carried out for a PMSM unit with a power of 1 kW, rated speed of 1,000 rpm, and rated torque of 6 Nm.

Design/methodology/approach

The PWM frequency ranged from 4 to 20 kHz with increments of 1 kHz. Measurements were taken for each of the foregoing frequencies, for the different load torques, and for the different rotation speeds including overspeed. The results achieved allow the PWM control frequency to be properly adjusted for each PMSM to operate the entire driving unit in the most efficient way and, in consequence, save energy consumed by the drive.

Findings

Obtained results may be used as a kind of background for the design of drive system.

Research limitations/implications

For a specific PMSM-based drive system, one can find the optimal PWM control frequency. This frequency depends on the rotation speed and torque of the motor. However, the validity of the results presented in the paper is limited. They are valid for the specific motor drive under test and cannot be generalized easily.

Originality/value

This work shows that there is some maximal efficiency of the entire system depending on the rotation speed, load torque and switching frequency of the power transistors. For a specific motor working in a certain condition, we can find the minimum power loss.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 1 June 1998

Ryszard Sikora, Mieczysl§aw Komorowski and Tomasz Chady

In the paper a new probe for eddy current testing of low conductivity materials is presented. The new probe has been applied for eddy current testing of H2SO4 water…

Abstract

In the paper a new probe for eddy current testing of low conductivity materials is presented. The new probe has been applied for eddy current testing of H2SO4 water solution. Results of measurements are presented.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 17 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 10 April 2007

Andrzej Brykalski and Tomasz Rogala

The goal of the paper is to introduce a new method of obtaining equivalent dynamic model of electromagnetic field quantities. Proposed algorithm allows approximation of…

Abstract

Purpose

The goal of the paper is to introduce a new method of obtaining equivalent dynamic model of electromagnetic field quantities. Proposed algorithm allows approximation of the frequency and step response by a simple inertial element model, with adjustable rank and delay. The values of the model parameters may be also used to describe the dynamics of considered system.

Design/methodology/approach

The dynamics of interesting field quantity in certain space location may be represented by an equivalent model of inertial element. Parameters of the model are identified using the solution of the problem in quasi‐stationary conditions for very limited number of excitation frequencies. These solutions are further used to build a matching approximation of real frequency response function (FRF).

Findings

The proposed method allows fast approximation of transient states of linear vector field. It may be useful with fast and relatively precise estimation of dynamic parameters of the electromagnetic field, e.g. in screening and eddy current problems.

Research limitations/implications

The main limitation of the method is the assumption of linearity of the problem. However, many practical tasks similar to the examples presented in the paper can be considered highly linear.

Practical implications

The main advantage of the method is that it allows fast estimation of the field dynamics without either solving the problem for whole range of frequencies or computing the transient state in time domain. It does not need the access to the original mass and stiffness matrices. Therefore, it may be used with commercial FEM software, which usually restricts access to its internal data.

Originality/value

The method is based on well known concept of moments, but the use of existing stationary FEM solutions for approximating transient states is a novel approach. Proposed procedure may be easily automated for the simulation environments with scripting capabilities.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

1 – 10 of 14