2015 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2015

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A jeśli nie „120” to co?
- Ziemowit Suligowski
2015 Forum Eksploatatora
Problem minimalnego dopuszczalnego obciążenia hydraulicznego kanalizacyjnej sieci grawitacyjnej. Znaczenie techniczne i ekonomiczne zagadnienia. Konsekwencje lekceważenia strony hydraulicznej - zatory, blokady, odory. Ocena warunków do powstawania zbiorczej kanalizacji w Polsce. Nierzetelność autorów programów i projektów.
A LABORATORY STAND FOR THE ANALYSIS OF DYNAMIC PROPERTIES OF THERMOCOUPLES
- Konrad Marszałkowski
- Patrycja Puzdrowska
2015 Full text Journal of Polish CIMEEAC
In the present elaboration, problems connected with measurements of high variable temperatures of gases are introduced and the impact of dynamic properties of different construction solutions of thermoelements on the accuracy of the measurements is considered. A laboratory stand built within research under doctoral thesis, destined for analysis of dynamic properties of thermocouples is also described. Results of numerical simulation of heat exchange between thermocouple and the gas that washes it (in this case - hot air) is presented as well as results of empirical experiments conducted on the laboratory stand built with the analysis of the obtained results.
A large family of filled skutterudites stabilized by electron count
- Huixia Luo
- Jason Krizan
- Lukas Muechler
- Neel Haldolaarachchige
- Tomasz Klimczuk
- Weiwei Xie
- Michael Fuccillo
- Claudia Felser
- Robert J. Cava
2015 Nature Communications
The Zintl concept is important in solid-state chemistry to explain how some compounds that combine electropositive and main group elements can be stable at formulas that at their simplest level do not make any sense. The electronegative elements in such compounds form a polyatomic electron-accepting molecule inside the solid, a ‘polyanion’, that fills its available energy states with electrons from the electropositive elements to obey fundamental electroncounting rules. Here we use this concept to discover a large family of filled skutterudites based on the group 9 transition metals Co, Rh, and Ir, the alkali, alkaline-earth, and rare-earth elements, and Sb4 polyanions. Forty-three new filled skutterudites are reported, with 63 compositional variations—results that can be extended to the synthesis of hundreds of additional new compounds. Many interesting electronic and magnetic properties can be expected in future studies of these new compounds.
A method for counting people attending large public events
- Krzysztof Kopaczewski
- Maciej Szczodrak
- Andrzej Czyżewski
- Henryk Krawczyk
2015 Full text MULTIMEDIA TOOLS AND APPLICATIONS
The algorithm for people counting in crowded scenes, based on the idea of virtual gate which uses optical flow method is presented. The concept and practical application of the developed algorithm under real conditions is depicted. The aim of the work is to estimate the number of people passing through entrances of a large sport hall. The most challenging problem was the unpredicted behavior of people while entering the building. The examined flow of people fluctuated between individual persons and dense crowd. A series of experiments during sport and entertainment events was made. The results of the experiments show a high efficiency of the elaborated algorithm.
A method of selecting light sources from night satellite scenes
- Katarzyna Bobkowska
- Marek Przyborski
- Jakub Szulwic
2015
Satellite images carries a lot of data. Very sophisticated methods of analyses may reveal very complicated nature of the observed objects. In case of night images, lights play the role of information sources. In this paper we would like to present results of the research aimed to describe light sources from satellite night images by providing description of their luminosity. The authors point source imaging data from the satellite systems available for use in the remote sensing analyses. They also present researches on the analysis of light propagation based on measurements of radiance of night city lights on the basis of modern satellite imaging systems and models of light propagation in the atmosphere. The paper includes a description of the technology of satellite scenes remote sense analysis with successive steps of the creation of night lighting map. The purpose of the article, in addition to the presentation of the current scientific achievements, based on the night satellite images showing the potential of this technology, is an attempt to draw attention to the problem of light pollution and to make a simple analysis of this phenomenon on the basis of such imaging.
A method of self-testing of analog circuits based on fully differential op-amps with theTCBF classifier
- Zbigniew Czaja
- Michał Kowalewski
2015
A new approach of self-testing of analog circuits based on fully differential op-amps of mixed-signal systems controlled by microcontrollers is presented. It consists of a measurement procedure and a fault diagnosis procedure. We measure voltage samples of a time response of a tested circuit on a stimulation of a unit step function given at the common-mode reference voltage input of the op-amp. The fault detection and fault localization is carried out by the TCBF neural network classifier.
A Model of Thermal Energy Storage According to the Convention of Bond Graphs (BG) and State Equations (SE)
- Marian Cichy
- Jacek Kropiwnicki
- Zbigniew Kneba
2015 Full text Polish Maritime Research
The main advantage of the use of the Bond Graphs method and State Equations for modeling energy systems with a complex structure (marine power plants, hybrid vehicles, etc.) is the ability to model the system components of different physical nature using identical theoretical basis. The paper presents a method of modeling thermal energy storage, which is in line with basic BG theory. Critical comments have been put forward concerning multiport energy storage introduced by other authors or the so-called C-field. In suggested approach the decision not to use pseudo Bond Graphs has been justified as not being in line with basic BG theory. On the basis of molecular physics it was considered that the state variable, in physical and mathematical sense, should be temperature rather than entropy. Examples of the application of the proposed approach to thermodynamic processes and heat exchange have been presented. The application of a single graph as a model for thermal energy storage has been illustrated by way of numerical simulation examples.
A modified method of vibration surveillance by using the optimal control at energy performance index
- Krzysztof Jan Kaliński
- Marek Galewski
2015 MECHANICAL SYSTEMS AND SIGNAL PROCESSING
A method of vibration surveillance by using the optimal control at energy performance index has been creatively modified. The suggested original modification depends on consideration of direct relationship between the measured acceleration signal and the optimal control command. The paper presents the results of experiments and Hardware- in-the-loop simulations of a new active vibration reduction algorithm based on the energy performance index idea modified in such a way, that it directly utilises the acceleration feedback signal. Promising prospects towards real application of the modified method in case of the high speed milling are predicted as well.
A multi-agent method for periodicity detection in distributed events
- Artur Opaliński
2015
Multi-agent systems working in constantly changing environments may be challenged by instantaneous unavailability of their autonomous agents caused e.g. by limited computing resources. A new method of self-organization of distributed service components is proposed, suitable for multi-agent systems. This method relies on particular agents carrying out separate analyzes of their individual processing loads or other specific events. Analysis is done separately by each agent, and is based only on information about agent’s own history of involvements in former tasks’ execution. Agents can also decide to replace peers should such need arise. The superposition of individual agents’ readiness periods emerges as a collective forecast of service load. By individual agents’ decisions appropriate amounts of agents get ready to execute forthcoming tasks.
A new approach to design of weather disruption-tolerant wireless mesh networks
- Jacek Rak
2015 Full text TELECOMMUNICATION SYSTEMS
Wireless Mesh Networks, offering transmission rates of 1–10 Gb/s per a millimeter-wave link (utilizing the 71–86 GHz band) seem to be a promising alternative to fiber optic backbone metropolitan area networks because of significantly lower costs of deployment and maintenance. However, despite providing high transmission rates in good weather conditions, high-frequency wireless links are very susceptible to weather disruptions. In particular, heavy rain storms may lead to remarkable signal attenuation. In this paper, we introduce a new transmission technique for wireless mesh networks to mitigate the negative effects of link quality degradation due to rain storms. In particular, our method is the first one to use information on forecasted attenuation of links based on radar measurements to perform in advance the periodic updates of a network topology. Our approach is easily implementable in practice, since functionality of dynamic antenna alignment is currently offered by a number of equipment vendors. Other contributions of the paper include presentation of the ILP model of weather-resistant links formation problem followed by analysis of its computational complexity. Results of simulations, performed for three real scenarios of rain storms, show that our approach is very efficient in reducing the level of signal attenuation.
A new approach to determination of the two-mass model parameters of railway current collector
- Andrzej Wilk
- Krzysztof Karwowski
- Sławomir Judek
- Mirosław Mizan
2015
The paper presents two mathematical models of railway current collectors both with two degrees of freedom. The first one, hereinafter Pantograph Articulated Model (PAM), has one degree of freedom in rotational motion and the second degree of freedom in translational motion. The second model, called henceforth as Pantograph Reference Model (PRM), has both degrees of freedom in translational motion. Differential equations of the PAM contain very complex coefficients dependent on rotation angles of individual arms. These coefficients can be determined analytically, based on the dimensional and material data of the collector. The mathematical formulation of the PRM is relatively simple, but the coefficients in differential equations of this model are equivalent. Defining them by way of analysis makes it necessary to adopt numerous simplifying assumptions. Application of the PRM is justifiable in many cases, particularly while analysing the interaction between the collector and the contact line. In order to ensure that the results of the analysis are reliable, it is necessary to define, with appropriate accuracy, the equivalent values of the PRM coefficients. This is usually done through experiments. The paper shows the way in which the PRM coefficient values are defined based on the PAM simulation. The advantage of the presented method is that it does not require a complex experimental setup.
A new approach to determination of the two-mass model parameters of railway current collector
- Andrzej Wilk
- Krzysztof Karwowski
- Sławomir Judek
- Mirosław Mizan
2015 Technika Transportu Szynowego
The paper presents two mathematical models of railway current collectors both with two degrees of freedom. The first one, hereinafter Pantograph Articulated Model (PAM), has one degree of freedom in rotational motion and the second degree of freedom in translational motion. The second model, called henceforth as Pantograph Reference Model (PRM), has both degrees of freedom in translational motion. Differential equations of the PAM contain very complex coefficients dependent on rotation angles of individual arms. These coefficients can be determined analytically, based on the dimensional and material data of the collector. The mathematical formulation of the PRM is relatively simple, but the coefficients in differential equations of this model are equivalent. Defining them by way of analysis makes it necessary to adopt numerous simplifying assumptions. Application of the PRM is justifiable in many cases, particularly while analysing the interaction between the collector and the contact line. In order to ensure that the results of the analysis are reliable, it is necessary to define, with appropriate accuracy, the equivalent values of the PRM coefficients. This is usually done through experiments. The paper shows the way in which the PRM coefficient values are defined based on the PAM simulation. The advantage of the presented method is that it does not require a complex experimental setup.
A new assay for simultaneous identification and differentiation of Klebsiella oxytoca strains
- Karolina Stojowska
- Beata Krawczyk
2015 Acta Biochimica Polonica
Bacterial strain typing, or identifying bacteria at the strain level, is particularly important for diagnosis, treatment, and epidemiological surveillance of bacterial infections. This is especially the case for bacteria exhibiting high levels of antibiotic resistance or virulence, and those involved in nosocomial or pandemic infections. Strain typing also has applications in studying bacterial population dynamics.
A New Canon of the Modernist Villa of the 1930s - a Villa with a Semicircular Veranda. The Post-War Continuation of the Idea
- Maria Sołtysik
2015
The articcle presents a new type of villa, which started to be popular in Gdynia in the 1930s. It was a villa with a semicircular veranda. Villas of that type were continously built also after the II World War
A New Expression for the 3-D Dyadic FDTD-Compatible Green's Function Based on Multidimensional Z-Transform
- Tomasz Stefański
2015 IEEE Antennas and Wireless Propagation Letters
In this letter, a new analytic expression for the time-domain discrete Green's function (DGF) is derived for the 3-D finite-difference time-domain (FDTD) grid. The derivation employs the multidimensional Z-transform and the impulse response of the discretized scalar wave equation (i.e., scalar DGF). The derived DGF expression involves elementary functions only and requires the implementation of a single function in the multiple-precision arithmetic. For its verification, antennas were simulated in the DGF formulation of the FDTD method with the use of the derived expression demonstrating the correctness of the derivation.
A new method of fault loop resistance measurement in low voltage systems with residual current devices
- Stanisław Czapp
- Kornel Borowski
- Jacek Klucznik
- Zbigniew Lubośny
- Krzysztof Dobrzyński
2015
This paper presents a new method of fault loop resistance measurement in low voltage systems with residual current devices. The method enables measuring fault loop resistance without nuisance tripping of residual current devices, by application an unconventional waveform of measurement current. It is important for proper verification of the effectiveness of protection against electric shock.
A new prototype of piezoelectric bending resonant transducer for analysis of soft tissues properties
- Łukasz Sienkiewicz
- Jean-Francois Rouchon
- Mieczysław Ronkowski
- Grzegorz Andrzej Kostro
2015 Full text Czasopismo Techniczne
This paper is devoted to a new piezoelectric bending resonant transducer prototype dedicated to the characterization of the mechanical properties of soft tissue. A general description of the actuator’s structure is presented including the basic principles of the measurement. The chosen geometry of the prototype is discussed and compared with the existing version. Constitutive equations are presented for the active and passive layer of the cantilever transducer. The prototype is verified by means of finite element method analysis. Results of the static and modal analysis are presented and discussed.
A new quaternion-based encryption method for DICOM images
- Mariusz Dzwonkowski
- Michał Papaj
- Roman Rykaczewski
2015 IEEE TRANSACTIONS ON IMAGE PROCESSING
In this paper, a new quaternion-based lossless encryption technique for digital image and communication on medicine (DICOM) images is proposed. We have scrutinized and slightly modified the concept of the DICOM network to point out the best location for the proposed encryption scheme, which significantly improves speed of DICOM images encryption in comparison with those originally embedded into DICOM advanced encryption standard and triple data encryption standard algorithms. The proposed algorithm decomposes a DICOM image into two 8-bit gray-tone images in order to perform encryption. The algorithm implements Feistel network like the scheme proposed by Sastry and Kumar. It uses special properties of quaternions to perform rotations of data sequences in 3D space for each of the cipher rounds. The images are written as Lipschitz quaternions, and modular arithmetic was implemented for operations with the quaternions. A computer-based analysis has been carried out, and the obtained results are shown at the end of this paper.
A new Toxoplasma gondii chimeric antigen containing fragments of SAG2, GRA1, and ROP1 proteins—impact of immunodominant sequences size on its diagnostic usefulness
- Bartłomiej Ferra
- Lucyna Holec-Gąsior
- Józef Kur
2015 Full text PARASITOLOGY RESEARCH
This study presents the first evaluation of new Toxoplasma gondii recombinant chimeric antigens containing three immunodominant regions of SAG2, GRA1, and one of two ROP1 fragments differing in length for the serodiagnosis of human toxoplasmosis. The recombinant chimeric antigens SAG2-GRA1-ROP1L (with large fragment of ROP1, 85-396 amino acid residues) and SAG2-GRA1-ROP1S (with a small fragment of ROP1, 85-250 amino acid residues) were obtained as fusion proteins containing His6-tags at both ends using an Escherichia coli expression system. The diagnostic utility of these chimeric antigens was determined using the enzyme-linked immunosorbent assay (ELISA) for the detection of specific anti-T. gondii immunoglobulin G (IgG). The IgG ELISA results obtained for the chimeric antigens were compared to those obtained for the use of Toxoplasma lysate antigen (TLA) and for a mixture of recombinant antigens containing rSAG2, rGRA1, and rROP1. The sensitivity of the IgG ELISA was similar for the SAG2-GRA1-ROP1L chimeric antigen (100 %), the mixture of three proteins (99.4 %) and the TLA (97.1 %), whereas the sensitivity of IgG ELISA with the SAG2-GRA1-ROP1S chimeric antigen was definitely lower, reaching 88.4 %. In conclusion, this study shows that SAG2-GRA1-ROP1L chimeric antigen can be useful for serodiagnosis of human toxoplasmosis with the use of the IgG ELISA assay. Therefore, the importance of proper selection of protein fragments for the construction of chimeric antigen with the highest reactivity in ELISA test is demonstrated.
A novel in vitro assay for assessing efficacy and toxicity of antifungals using human leukaemic cells infected with Candida albicans
- Joanna Boros-Majewska
- Ł Turczyk
- X. Wei
- Sławomir Milewski
- David W. Williams
2015 JOURNAL OF APPLIED MICROBIOLOGY
Aims: This study describes a novel in vitro assay that simultaneously determines antifungal efficiency and host cell toxicity using suspensions of human leukaemic cells (HL-60) infected with Candida albicans. Methods and Results: The effect of Candida infection on host cell viability was evaluated by the microscopy of trypan blue-stained cells and lactate dehydrogenase (LDH) activity. The in vitro ‘drug potency assay’ utilized the Cell Counting Kit-8 and measured post-antifungal treatment viability of Candida-infected HL-60 cells and the ability of the antifungal treatment to prevent infection. LDH activity showed that 42% 40 and 853% 740 of HL-60 cells were killed following Candida infection at the multiplicity of infection (MOI) of 1 : 1 and 1 : 5, respectively. The antifungal nystatin (078–25 lmol l 1) was found to inhibit C. albicans infection as seen by the significantly increased viability of HL-60 cells. Cytotoxicity of nystatin towards infected HL-60 cells was evident at higher concentrations and this was also confirmed by propidium iodide staining. Conclusions: An assay using undisturbed cell suspension conditions was successfully developed for assessing the selectivity of the antifungal therapy in the host-Candida environment. Significance and Impact of the Study: The assay employing Candida infection of host cell suspensions represents a promising method for testing interactions of antifungal compounds with both fungal and host cells.