2014 - Repozytorium publikacji - Politechnika Gdańska

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Contextualizing a Knowledge Base by Approximation – A Case Study
- Krzysztof Goczyła
- Aleksander Waloszek
- Wojciech Waloszek
2014 Communications in Computer and Information Science
Modular knowledge bases give their users opportunity to store and access knowledge at different levels of generality. In this paper we present how to organize a modular knowledge bases organized into contexts in which a user can express their knowledge in much simplified way, yet without losing its precision. The work is centered around the notion of approximation - i.e. reducing the arity of predicates used. The presentation is based on a case-study conducted with CongloS system within a large-scale national project.
Continuous learning as a method of raising qualifications – the perspective of workers, employers and training organizations
- Marzena Grzesiak
2014
Continuous learning is discussed in strategic documents of Poland and the European Union. In Poland, the idea of continuous learning is not very popular. However, in the context of strong competition in the labour market and the progressive globalization processes, the skills issue takes on new meaning — both for employees and employers. In order to adapt skills to labour market needs it is necessary to conduct adequate studies and adapt the offer of training companies to their results.
Control system for contactless electrical energy transfer with varying air gap
- Sławomir Judek
2014
Inductive power transfer (IPT) is a system by which electrical energy may be transmitted without electrical connection through a large air gap between coils. Systems usually considered in the literature are the ones with a constant air gap. The paper describes the analysis of IPT, which allows for supplying an electrical load in the conditions of slow, in relation to the dynamics of power supply, changes in the dimensions of the air gap. The system has been proposed which controls the frequency of inverter output voltage in order to maintain resonance for actual air gap dimensions. The IPT control system stability for a selected structure has also been determined. Theoretical developments are compared with experimental results on the prototype IPT.
Coplanar Waveguide Fed Ultra-Wideband Antenna Over the Planar and Cylindrical Surfaces
- Rafał Lech
- Wojciech Marynowski
- Adam Kusiek
2014
The investigation of coplanar waveguide fed ultra-wideband antenna and the influence of the proximity of different materials on the reflection coefficients and radiation character-istics is presented. The antenna is composed of two circular coplanar strips which enclose slot aperture of similar shape and is designed on a thin and flexible substrate. From the modeling and experimental tests the antenna shows good performance in 2 - 15GHz frequency range with return losses better than 10dB. It is shown that the proximity of different, non-metalic materials does not significantly affect antenna performance. The proximity of metalic screens deteriorates its radiation pattern and reflection coefficient. However with the correct choice of the distance between screen and antenna the required level of return losses can be provided.
Coplanar Waveguide-Fed Broadband Microwave Devices with (or without) a Thin Dielectric Substrate for Use in Flexible Electronic Systems
- Rafał Lech
- Wojciech Marynowski
- Adam Kusiek
- Jerzy Mazur
2014 Pełny tekst International Journal of Antennas and Propagation
Two examples of microwave devices, fed by a coplanar waveguide and realized on a thin substrate (or without such a substrate), are employed to investigate the influence of devices’ curvatures and the proximity of different materials on their parameters. To perform the tests, a broadband antenna and a low-pass filter are chosen. A feeding coplanar waveguide is realized on a dielectric material brick attached to an SMA connector and the main device structure is placed in the air or on a thin substrate. The utilization of a thin substrate or its removal from the structure gives rise to the possibility of placing the devices on curved surfaces. The investigated devices are redesigned and manufactured. The antenna has a total size of 46 mm × 44 mm and covers a frequency range of 2.4–35 GHz which gives a 174% fractional bandwidth. The filter has a total size of 50 mm × 80 mm and its bandwidth has a cutoff frequency of 3.4 GHz. The obtained results are verified by measurements and good agreement is achieved.
Corporate Governance and Ownership Structure in the Top 30 Listed Non Financial Companies in Poland
- Magdalena Popowska
2014
This paper offers a first analysis of the relationships between corporate governance models and rules and ownership structure of the top 30 Polish firms listed at the WSE (not considering foreign firms and/or the Polish branches of foreign firms listed at the same stock exchange, nor the financial companies and the banks). The general picture depicted by this analysis is putting into evidence the increasing importance of institutional investors (such as pension funds, mainly controlled by big foreign financial institutions). Their role is contributing – as in many other European financial market – to introduce a higher level of efficiency and a wider disclosure of information within a system where the highly concentrate ownership structure of most of these firms permitted until a recent past – and to some extent still permits - a relatively low level of transparency. Another relevant result of this analysis is the increasing similarity of the Polish ownership structure of the biggest listed companies to some other models, like the German one, where a cross shareholding structure among big groups and/or big block holders cohabits with another model where the ownership structure still depends very much on the role of the family or of the group of founders. Both cases contribute to a very strong stabilization process of the ownership structure of the top 30 Polish firms. If this is self-evident in case of some oil and/or energy companies, still largely controlled by the State, it offers a new image of corporate Poland more than twenty years after the beginning of the transition to a market economy.
Correlation between structural and electrical properties in highly porous (Y,Sr)(Ti,Nb)O3-delta SOFC anodes
- Tadeusz Miruszewski
- Bartosz Jakub Trawiński
- Maciej Gałka
- Jędrzej Morzy
- Beata Bochentyn
- Jakub Karczewski
- Paweł Gdaniec
- Maria Gazda
- Bogusław Kusz
2014 Pełny tekst MATERIALS SCIENCE-POLAND
In order to find a relationship between structural and electrical properties, niobium and yttrium doped SrTiO3 ceramics were prepared via solid-state reaction. The samples were sintered in hydrogen and air conditions. The samples were also fabricated with a pore-former to obtain highly porous specimens. The electrical properties of Nb-doped SrTiO3 samples and yttrium and niobium co-doped SrTiO3 were compared. The comparable electrical properties were observed and discussed according to previous literature reports. It was noticed that the synthesis in a reducing hydrogen atmosphere can increase the solubility of dopants. Moreover, the samples sintered in air presented lower conductivity level and worse structural properties than the samples sintered in hydrogen. The explanation of obtained results was also suggested and discussed.
Co-simulation strategy of transient CFD and heat transfer in building thermal envelope based on calibrated heat transfer coefficients
- Krzysztof Arendt
- Marek Krzaczek
2014 INTERNATIONAL JOURNAL OF THERMAL SCIENCES
The paper presents a strategy to develop a fully transient numerical model of a heat transfer in building, using a transient CFD model of indoor air and a thermal envelope model, running in a co-simulation. The strategy relies on the utilization of RANS with a high-Re turbulence model and a wall function, which enables to use a coarse computational mesh limiting the computational time. Since wall functions give invalid heat transfer coefficients in thermally developing indoor air regions and the exact location of these regions is not known in indoor spaces, a new air-wall heat transfer calibration procedure is adopted in the co-simulation. It is assumed that there is a uniform surface-averaged and time-dependent heat transfer coefficient per surface, extracted from the CFD solution. The calibration procedure is based on the near-wall mesh density adjustment to obtain surface-average heat transfer coefficients close to those calculated from empirical relationships for natural and forced convection. No local heat transfer coefficients are checked and no dimensionless wall distances yþ are monitored during the simulation. Due to the calibration it is ensured that the average air-wall heat transfer rate is accurate despite the use of wall functions. The capabilities of the model developed based on the strategy are presented in the case study: the analysis of the influence of wall thermal capacitance on indoor environment in a single well-ventilated room.
Cost-Effective and Sufficiently Precise Integration Method Adapted to the FEM Calculations of Bone Tissue
- Katarzyna Mazur
- Leszek Dąbrowski
2014 Computational Methods in Science and Technology
The technique of Young’s modulus variation in the finite element is not spread in biomechanics. Our future goal is to adapt this technique to bone tissue strength calculations. The aim of this paper is to present the necessary studies of the element’s integration method that takes into account changes in material properties. For research purposes, a virtual sample with the size and distribution of mechanical properties similar to these in a human femoral wall, was used. WinPython, an environment of Python programming language was used to perform simulations. Results with the proposed element were compared with ANSYS element PLANE42 (with constant Young modulus). The modeled sample was calculated with five different integration methods at five different mesh densities. Considered integration methods showed a very high correlation of results. Two-point Gauss Quadrature Rule proved to be the most advantageous. Results obtained by this method deviate only slightly from the pattern, while the computing time was significantly lower than others. Performed studies have shown that accuracy of the solution depends largely on the mesh density of the sample. Application of the simplest integration method in combination with four times coarser mesh density than in ANSYS with a standard component still allowed to obtain better results.
Cough influence on fascia-mesh system built for a hernia repair - an experimental research
- Agnieszka Tomaszewska
- Izabela Lubowiecka
- Czesław Szymczak
2014
An experimental approach to identify stronger and weaker fixation schemes in laparoscopic ventral hernia repair is presented in the paper. Two types of implants, whose mechanical properties are significantly different and five kinds of connectors are considered. Physical models of operated hernia have been built using those materials and porcine abdominal tissue. The models have been subjected to dynamic impulse load, similar to post-operative cough, a common cause of the tissue-implant break down and the sickness recurrence. As a result, a set of observations is made, which is a basis for medical recommendations.
Creating a Realible Music Discovery and Recomendation System
- Bożena Kostek
- Piotr Hoffmann
- Andrzej Kaczmarek
- Paweł Spaleniak
2014
The aim of this paper is to show problems related to creating a reliable music dis-covery system. The SYNAT database that contains audio files is used for the purpose of experiments. The files are divided into 22 classes corresponding to music genres with different cardinality. Of utmost importance for a reliable music recommendation system are the assignment of audio files to their appropriate gen-res and optimum parameterization for music-genre recognition. Hence, the start-ing point is audio file filtering, which can only be done automatically, but to a limited extent, when based on low-level signal processing features. Therefore, a variety of parameterization techniques are shortly reviewed in the context of their suitability to music retrieval from a large music database. In addition, some sig-nificant problems related to choosing an excerpt of audio file for an acoustic anal-ysis and parameterization are pointed out. Then, experiments showing results of searching for songs that bear the greatest resemblance to the song in a given que-ry are presented. In this way music recommendation system may be created that enables to retrieve songs that are similar to each other in terms of their low-level feature description and genre inclusion. The experiments performed also provide basis for more general observations and conclusions.
Creative sprints: an unplanned broad agile evaluation and redesign process.
- Igor Garnik
- Marcin Sikorski
- Gilbert Cockton
2014
We report how a request for routine usability work rapidly evolved into a novel agile process for evaluation and redesign. This process is described and then analysed to identify reasons for success. This analysis supports realistic knowledge transfer between User Experience professionals by outlining how similar future processes could succeed.
Critical Case Stochastic Phylogenetic Tree Model via the Laplace Transform
- Krzysztof Bartoszek
- Michał Krzemiński
2014 Pełny tekst Demonstratio Mathematica
Birth–and–death models are now a common mathematical tool to describe branching patterns observed in real–world phylogenetic trees. Liggett and Schinazi (2009) is one such example. The authors propose a simple birth–and–death model that is compatible with phylogenetic trees of both influenza and HIV, depending on the birth rate parameter. An interesting special case of this model is the critical case where the birth rate equals the death rate. This is a non–trivial situation and to study its asymptotic behaviour we employed the Laplace transform. With this, we correct the proof of Liggett and Schinazi (2009) in the critical case.
Critical perspectives on media architecture: is it still possible to design projects without negatively affecting urban nighttime environments and will the future remain dynamic, bright and multi-colored?
- Karolina Zielińska-Dąbkowska
2014
Nowadays, due to advances in electrical devices, new digital media, lighting, information and communication technologies, cities are being used 24/7. The paper discusses critical aspects of Media Architecture in the context of public spaces as well as urban nighttime environments from the perspective of a practising lighting architect. The author examines recent issues of negative design approaches and presents proposals for improving future projects in the form of guiding principles. Additionally, to better illustrate the phenomenon, an attempt has been made to standardize terminology and to clarify the topic of Media Architecture in the context of artificial light used in the urban environment based on the author's practical and theoretical research work in the field.
Critical Success Factors for Knowledge Management in SMEs in the KIBS Sector
- Małgorzata Zięba
2014
The purpose of this paper is to examine knowledge management practices and critical success factors (CSFs) for their introduction in small and medium-sized enterprises (SMEs) in the knowledge-intensive business services (KIBS) sector. Methodology: The paper is based on the results of an exploratory qualitative survey involving owners and managers of small and medium-sized companies operating in the KIBS sector. In the survey, eight in-depth interviews were carried out with representatives of SMEs offering KIBS located in the Pomeranian region in Poland. Findings: The results of this study clearly indicate that among the most important CSFs for knowledge management (KM) in the companies analysed are factors connected with human resources and appropriate attitudes towards KM. The companies examined often indicated factors associated with employees and management. This illustrates an awareness on the part of KIBS companies of the significance of human resources: as they offer services based on knowledge, they know that if their employees do not want to implement practices connected with knowledge and its management, their implementation will not be possible. Research limitations: The research results are limited to KIBS companies from the Pomeranian region in Poland. They cannot illustrate a typical picture for companies in other countries. Furthermore, the study presented is an exploratory one and consequently the topic explored requires further examination. Practical implications: This study might offer good guidelines for SMEs owners and managers wishing to introduce KM practices. It indicates the factors that support and hinder the success of KM introduction in this type of company. SMEs that have already introduced KM might also benefit by revising their approach to the concept and paying more attention to the CSFs identified in the study. Originality/value: Although the field of knowledge management in large companies has been examined thoroughly in the literature, there is still not much research on the CSFs for KM introduction in smaller companies. This study identifies and examines critical success factors for knowledge management in such companies (SMEs in the KIBS sector), which by definition need to manage knowledge in an efficient and effective way. The paper also suggests further research possibilities in this area.
Cross-Cultural Interactions between Expatriates and Local Managers in the Light of Positive Organizational Behaviour
- Sylwia Przytuła
- Malgorzata Rozkwitalska
- Michał Chmielecki
- Łukasz Sułkowski
- Beata Basińska
2014 Social Sciences/ Socialiniai Mokslai
The main purpose of this article is to identify the ‘individual positive deviance’ presented by expatriates and local managers in their mutual cooperation. The theoretical basis for the publication is the discussion of the Positive Organizational Behaviour (POB) essence and the application of this approach in the area of expatriation. Attitudes, behaviour, working style and personality traits of employees of different nationalities and cultures undoubtedly influence the efficient pursuit of business objectives. Empirical knowledge refers to the research concerning mutual positive perception of Polish managers and expats working in subsidiaries of foreign companies established in Poland. The research in the form of structured interviews was carried out on two groups of managers: 27 expatriate managers working in Poland and 31 Polish managers who cooperate with expatriates during their everyday work. The research findings proved that the individual positives of expatriates from the Polish managers’ point of view are: openness to other people and other cultures, cognitive curiosity, sociability and willingness to share knowledge. According to expats, Polish managers are hard-working, dedicated and desired for continuous learning. In interpersonal relationships Polish managers are open, warm and friendly; their approach to many issues is very emotional.
Cross-linking of epoxy-oligomeric mixtures in the presence of modified phenol-formaldehyde resins
- M. Bratychak
- Galyna Strap
- Piotr Bruździak
- Józef Haponiuk
2014 Pełny tekst Ukrainian Chemistry Journal
Cross-linking of epoxy oligomeric mixtures consisting of industrial epoxy resin ED-20, oligoetheracrylate TGM-3, peroxide derivative of epoxy resin ED-24 and phenol-formaldehyde oligomer with unsaturated methacrylate fragments or peroxide groups was studied in the presence of polyethylenepolyamine at room temperature and heated to 383, 403 or 423 K for 15, 30, 45, 60 and 75 minute. The influence of mixture composition, temperature and cross-linking time on the content of gel fraction in the samples and the hardness of the polymer film was established. Using IR spectroscopy the formation of spatial structures of cross-linked epoxy oligomeric mixtures was confirmed.
Cross-linking of polymer films using phenol-formaldehyde resins with different functional groups
- Galyna Strap
- Jacek Namieśnik
- M. Bratychak
2014
Well-know phenol-formaldehyde resins are used in the production of press-materials, glues, protective coating, mastics. They take a special place among known oligomers because the products based on them are characterized by a low cost and a series of positive properties. Aim of the work: to show the possibility to create polymeric films based on epoxy resins and modified phenol-formaldehyde resins, which contain unsaturated double bonds or peroxide groups.
Crowdsourcing and Volunteer Computing as Distributed Approach for Problem Solving
- Jerzy Balicki
- Piotr Brudło
- Piotr Szpryngier
2014
In this paper, a combination between volunteer computing and crowdsourcing is presented. Two paradigms of the web computing are described, analyzed and compared in detail: grid computing and volunteer computing. Characteristics of BOINC and its contribution to global Internet processing are shown with the stress put onto applications the system can facilitate and problems it can solve. An alternative instance of a grid computing system, elaborated at the Gdansk University of Technology - the system Comcute, is presented with its abilities of distributed processing highlighted and practical examples of various applications demonstrated.
Crystal structure and electronic structure of CePt2In7
- Tomasz Klimczuk
- O. Walter
- L. Müchler
- J. W. Krizan
- F. Kinnart
- R. J. Cava
2014 JOURNAL OF PHYSICS-CONDENSED MATTER
We report a corrected crystal structure for the CePt2In7 superconductor, refined from single crystal x-ray diffraction data. The corrected crystal structure shows a different Pt–In stacking along the c-direction in this layered material than was previously reported. In addition, all of the atomic sites are fully occupied with no evidence of atom site mixing, resolving a discrepancy between the observed high resistivity ratio of the material and the atomic disorder present in the previous structural model. The Ce–Pt distance and coordination is typical of that seen in all other reported CenMmIn3n+2 m compounds. Our band structure calculations based on the correct structure reveal three bands at the Fermi level that are more 3D than those previously proposed, and density functional theory (DFT) calculations show that the new structure has a significantly lower energy.