2014 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2014

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A predictive estimation based control strategy for a quasi-resonant dc-link inverter
- Marek Turzyński
- Piotr Banach
- Piotr Murawski
- Robert Pepliński
- Piotr Chrzan
2014 Full text Bulletin of the Polish Academy of Sciences-Technical Sciences
In this paper the predictive estimation based control strategy for a quasi-resonant dc link inverter (PQRDCLI) is developed. Instead of direct measurement of dc link input inverter current – its estimation with one step prediction is applied. The PQRDCLI fed induction motor, controlled with a predictive current estimation stabilized inverter output voltage slopes independently of load. Moreover, reduction of overvoltage spikes and common mode motor currents was achieved. Obtained results are verified by the Saber system simulation and experimental tests in a laboratory setup.
A quasi-2D small-signal MOSFET model - main results
- Wiesław Kordalski
2014
Main results stemming from a new quasi 2D non-quasi-static small-signal four-terminal model of the MOSFET are presented in this work. The model is experimentally verified up to 30 GHz.
A quasi-2D small-signal MOSFET model - main results
- Wiesław Kordalski
2014 Elektronika : konstrukcje, technologie, zastosowania
Dynamic properties of the MOS transistor under small-signal excitation are determined by kinetic parameters of the carriers injected into the channel, i.e., the low-field mobility, velocity saturation, mobility at the quiescent-point (Q-point), longitudinal electric field in the channel, by dynamic properties of the channel, as well as by an electrical coupling between the perturbed carrier concentration in the channel and the gate and body. The above-mentioned phenomena are essential for a non-quasi-static (NQS) approach to modeling of the MOSFET, which is extremely important when the MOS transistor operates near or above the cut-off frequency fT. The purpose of this work is to present some important results of a new quasi 2D non-quasi-static small-signal four-terminal model of the MOSFET which is based on the results of [1], [2], where, respectively, a quasi 2D representation of the channel is defined and basic equations for the time-dependent quasi-two-space-dimensional non-quasi-static small-signal MOSFET model are derived from first principles. Considerations presented here are performed for a p-channel MOS transistor. In Section 2, a preliminary time-domain analysis of the transistor is carried out. Three fundamental equations, namely, Poisson’s equation for the quasi 2D representation of the transistor, continuity equation, and current transport equation for carriers in the channel are presented in Section 3. Small-signal terminal currents are defined in Section 4. Section 5 provides a validation of the model and concluding remarks.
A quaternion-based modified feistel cipher for multimedia transmission
- Mariusz Dzwonkowski
- Roman Rykaczewski
2014 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
In this paper a quaternion-based modified Feistel Cipher is proposed. The algorithm is based on the scheme proposed by Sastry and Kumar (2012). Our algorithm uses special properties of quaternions to perform rotations of data sequences in 3D space for each of the cipher rounds. The plaintext (image in gray-tone) is divided into two square matrices of equal size which consist of Lipschitz quaternions. A modular arithmetic was implemented for operations with quaternions. A computer-based analysis has been carried out and obtained results are shown at the end of this paper.
A Regular Expression Matching Application with Configurable Data Intensity for Testing Heterogeneous HPC Systems
- Paweł Rościszewski
- Jan Cychnerski
- Adam Brzeski
2014
Modern High Performance Computing (HPC) systems are becoming increasingly heterogeneous in terms of utilized hardware, as well as software solutions. The problems, that we wish to efficiently solve using those systems have different complexity, not only considering magnitude, but also the type of complexity: computation, data or communication intensity. Developing new mechanisms for dealing with those complexities or choosing an existing system that suits the characteristics of our application best, requires defining and implementing adequate test applications. In this paper, we propose a regular expression matching application, which can be configured to reflect a certain computation to data intensity ratio. We support its usefulness by showing execution times of our OpenCL implementation on selected CPU and GPU devices. The results depend on input data sizes, numbers of parallel threads, but most importantly on the wildcard character properties, which allow to prepare test cases from a wide range of computation to data intensity ratios.
A review of amide bond formation in microwave organic synthesis
- Natalia Łukasik
- Ewa Wagner-Wysiecka
2014 CURRENT ORGANIC SYNTHESIS
Microwave-Assisted Organic Synthesis (MAOS) is one of the most current trends in organic chemistry. Herein, both the most popular and new approaches in microwave-syntheses of very important linkage in Nature - amide bond - are overviewed and compared with conventional synthetic routes.
A robust design of a numerically demanding compact rat-race coupler
- Piotr Kurgan
- Adrian Bekasiewicz
2014 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
A fast and accurate design procedure of a computationally expensive microwave circuit has been presented step-by-step and experimentally validated on the basis of a compact rat-race coupler (RRC) comprising slow-wave resonant structures (SWRSs). The final compact RRC solution has been obtained by means of a sequential optimization scheme exploiting the implicit space mapping (ISM) algorithm. A well-suited surrogate optimization starting point as well as a considerable limitation of the surrogate optimization variables contribute significantly to the numerical efficiency of the method proposed. The final design, offering 85% size reduction together with a satisfactory performance, has been obtained with only a handful of EM simulations. The experimental validation of the method has been successfully conducted
A Self-Equalized Waveguide Filter With Frequency-Dependent (Resonant) Couplings
- Łukasz Szydłowski
- Michał Mrozowski
2014 IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
This letter presents a design of a fifth-order linear phase filter with frequency-dependent couplings. The filter is composed of a triplet that is directly coupled to two resonators at the input and output. To provide group delay flattening a cross-coupling in the trisection has a strongly dispersive character with a negative slope parameter. To achieve this, an E-plane stub with a septum was used. To further improve the filter selectivity, the direct couplings connecting the triplet to the outer resonators are also frequency dependent. In this particular case, these were implemented in the form of two partial-height conducting posts to provide two imaginary transmission zeros, one on each side of the stopband. With three strongly dispersive couplings, four zeros were obtained in a fifth-order topology that generates only one imaginary transmission zero in a classical design. The filter was realized in the WR-90 waveguide and the measured characteristics match the simulated ones, confirming the validity of the concept.
A standardised static in vitro digestion method suitable for food – an international consensus
- M Minekus
- M Alminger
- P Alvito
- S Ballance
- T Bohn
- C Bourlieu
- F Carrière
- R Boutrou
- M Corredig
- D Dupont
- C Dufour
- L Egger
- M Golding
- S Karakaya
- B Kirkhus
- S Le
- Adam Macierzanka
- Alan Mackie
- S Marze
- D McClements
- O Ménard
- I Recio
- C Santos
- R Singh
- G Vegarud
- M Wickham
- W Weitschies
- A Brodkorb
2014 Full text Food & Function
Simulated gastro-intestinal digestion is widely employed in many fields of food and nutritional sciences, as conducting human trials are often costly, resource intensive, and ethically disputable. As a consequence, in vitro alternatives that determine endpoints such as the bioaccessibility of nutrients and non-nutrients or the digestibility of macronutrients (e.g. lipids, proteins and carbohydrates) are used for screening and building new hypotheses. Various digestion models have been proposed, often impeding the possibility to compare results across research teams. For example, a large variety of enzymes from different sources such as of porcine, rabbit or human origin have been used, differing in their activity and characterization. Differences in pH, mineral type, ionic strength and digestion time, which alter enzyme activity and other phenomena, may also considerably alter results. Other parameters such as the presence of phospholipids, individual enzymes such as gastric lipase and digestive emulsifiers vs. their mixtures (e.g. pancreatin and bile salts), and the ratio of food bolus to digestive fluids, have also been discussed at length. In the present consensus paper, within the COST Infogest network, we propose a general standardised and practical static digestion method based on physiologically relevant conditions that can be applied for various endpoints, which may be amended to accommodate further specific requirements. A frameset of parameters including the oral, gastric and small intestinal digestion are outlined and their relevance discussed in relation to available in vivo data and enzymes. This consensus paper will give a detailed protocol and a line-by-line, guidance, recommendations and justifications but also limitation of the proposed model. This harmonised static, in vitro digestion method for food should aid the production of more comparable data in the future. © 2014 the Partner Organisations.
A survey on known values and bounds on the Shannon capacity
- Marcin Jurkiewicz
2014
In this survey we present exact values and bounds on the Shannon capacity for different classes of graphs, for example for regular graphs and Kneser graphs. Additionally, we show a relation between Ramsey numbers and Shannon capacity.
A System for Cooling Electronic Elements with EHD Coolant Flow
- Mateusz Tański
- Marek Kocik
- Robert Barbucha
- Katarzyna Garasz
- Jerzy Mizeraczyk
- Jarosław Kraśniewski
- Maciej Oleksy
- A. Hapka
- Włodzimierz Janke
2014 Full text Journal of Physics : Conference Series
A system for cooling electronic components where the liquid coolant flow is forced with ion-drag type EHD micropumps was tested.
A System for Heart Sounds Classification
- Grzegorz Redlarski
- Dawid Gradolewski
- Aleksander Pałkowski
2014 Full text PLOS ONE
The future of quick and efficient disease diagnosis lays in the development of reliable non-invasive methods. As for the cardiac diseases – one of the major causes of death around the globe – a concept of an electronic stethoscope equipped with an automatic heart tone identification system appears to be the best solution. Thanks to the advancement in technology, the quality of phonocardiography signals is no longer an issue. However, appropriate algorithms for autodiagnosis systems of heart diseases that could be capable of distinguishing most of known pathological states have not been yet developed. The main issue is non-stationary character of phonocardiography signals as well as a wide range of distinguishable pathological heart sounds. In this paper a new heart sound classification technique, which might find use in medical diagnostic systems, is presented. It is shown that by combining Linear Predictive Coding coefficients, used for future extraction, with a classifier built upon combining Support Vector Machine and Modified Cuckoo Search algorithm, an improvement in performance of the diagnostic system, in terms of accuracy, complexity and range of distinguishable heart sounds, can be made. The developed system achieved accuracy above 93% for all considered cases including simultaneous identification of twelve different heart sound classes. The respective system is compared with four different major classification methods, proving its reliability.
A Systematic Search for New Coupling Schemes of Cross-Coupled Resonator Bandpass Filters
- Adam Lamęcki
2014 Full text RADIOENGINEERING
In this paper, a systematic approach to an extensive search for topologies of cross-coupled filters with generalized Chebyshev response is presented. The technique applies graph theory to find unique, nonisomorphic filter configurations, and tests whether a specific frequency response can be realized in a given set of topologies. The results of the search are then stored in a database of possible filter configurations.
A Workflow Application for Parallel Processing of Big Data from an Internet Portal
- Paweł Czarnul
2014
The paper presents a workflow application for efficient parallel processing of data downloaded from an Internet portal. The workflow partitions input files into subdirectories which are further split for parallel processing by services installed on distinct computer nodes. This way, analysis of the first ready subdirectories can start fast and is handled by services implemented as parallel multithreaded applications using multiple cores of modern CPUs. The goal is to assess achievable speed-ups and determine which factors influence scalability and to what degree. Data processing services were implemented for assessment of context (positive or negative) in which the given keyword appears in a document. The testbed application used these services to determine how a particular brand was recognized by either authors of articles or readers in comments in a specific Internet portal focused on new technologies. Obtained execution times as well as speed-ups are presented for data sets of various sizes along with discussion on how factors such as load imbalance and memory/disk bottlenecks limit performance
Abstract class method use on common characteristics of UE regions for better road safety management in these regions.
- Joanna Wachnicka
- Leszek Smolarek
2014
Road Safety is the significant problem requiring still a lot of attention. Despite lots of actions for road fatalities reduction, in many countries or regions situation doesn't improve as good as in the other cases. Even if these actions are very similar. It is so difficult issue, that the answer why is that happens hasn't been found yet. In this paper authors focused on the road network of European regions, classified as NUTS 2 in statistical databases of the European Union. Earlier surveys of authors indicate that attempt to make useful models for group of all regions in EU is difficult issue, because it is hard to create model with acceptable level of fitness. Initial analyses of road safety on regional levels indicate that regions create groups of regions similar because of road safety level and factors which have impact on it. That's why the thesis was stated, that if we aggregate regions in smaller groups we can create models with better fitness. Results of such approach for road safety in regions and mathematical modelling was presented in this article.
Accelerating Video Frames Classification With Metric Based Scene Segmentation
- Adam Blokus
- Jan Cychnerski
- Adam Brzeski
2014 Full text International Journal of Innovative Research in Computer and Communication Engineering
This paper addresses the problem of the efficient classification of images in a video stream in cases, where all of the video has to be labeled. Realizing the similarity of consecutive frames, we introduce a set of simple metrics to measure that similarity. To use these observations for decreasing the number of necessary classifications, we propose a scene segmentation algorithm. Performed experiments have evaluated the acquired scene sizes and classification accuracy resulting from the usage of different similarity metrics with our algorithm. As a result, we have identified those metrics from the considered set, which show the best characteristics for usage in scene segmentation.
Acceleration of decision making in sound event recognition employing supercomputing cluster
- Kuba Łopatka
- Andrzej Czyżewski
2014 INFORMATION SCIENCES
Parallel processing of audio data streams is introduced to shorten the decision making time in hazardous sound event recognition. A supercomputing cluster environment with a framework dedicated to processing multimedia data streams in real time is used. The sound event recognition algorithms employed are based on detecting foreground events, calculating their features in short time frames, and classifying the events with Support Vector Machine. Different strategies for improving the decision time are introduced. The experiments with the presented strategies are conducted and the results are presented.
Accelerator of the entrepreneurship: suburbs in the coastal metropolis of GOM
- Justyna Martyniuk-Pęczek
- Olga Martyniuk
- Tomasz Parteka
2014
Polish model of suburban structure is made of variety types of enterprises in different scales, and a range of housing. However this mass of unordered structure with its urban development problems, often leads to the establishment of business and also the development of local entrepreneurship. This article investigates SME sector located in the suburban area of costal metropolis GOM to prove the thesis that the positive effect of Polish suburbanization process is the high level of entrepreneurship located there. Additionally, authors formulate the thesis that the communities adjacent to the central cities have higher economic activity than ones in the periphery. In their research basing on statistical data authors analyse economic activity in 44 communities in GOM in 2013.
Accelerometer-based Human Activity Recognition and the Impact of the Sample Size
- Adam Harasimowicz
- Tomasz Dziubich
- Adam Brzeski
2014
The presented study focused on the recognition of eight user activities (e.g. walking, lying, climbing stairs) basing on the measurements from an accelerometer embedded in a mobile device. It is assumed that the device is carried in a specific location of the user’s clothing. Three types of classifiers were tested on different sizes of the samples. The influence of the time window (the duration of a single trial) on selected activities and methods was investigated. A comparison with existing methods from the literature is presented.
Acclimation of denitrifying activated sludge to a single vs. complex external carbon source during a start-up of sequencing batch reactors treating ammonium-rich anaerobic sludge digester liquors
- Krzysztof Czerwionka
- Aneta Łuczkiewicz
- Joanna Majtacz
- Przemysław Kowal
- Katarzyna Jankowska
- Sławomir Ciesielski
- Krishna Pagilla
- Jacek Mąkinia
2014 BIODEGRADATION
In this study, denitrification of ammonium- reach anaerobic sludge digester liquor was investigated during start-up periods of two laboratory- scale ‘‘fill-and-draw’’ reactors. One reactor was fed with a single carbon source (ethanol), whereas the other reactor was fed with a complex carbon source (fusel oil). During two acclimation experiments, the structure of microbial community involved in denitrification was analyzed using 16S rDNA polymerase chain reaction-denaturing gradient gel electrophoresis ingerprints and fluorescent in situ hybridization. The characteristics of the mixed liquor were additionally supported by regular measurements of nitrate uptake rates. The addition of fusel oil and ethanol resulted in a significant enhancement of the denitrification rate and efficiency combined with the increasing volumetric addition of sludge digester liquor up to 15 % of the reactor volume. The microbiological analyses revealed that the addition of sludge digester liquor as well as both external carbon sources (fusel oil and ethanol) did not affect the structure of microbial communities in a severe way. In both reactors, Curvibacter sp. and Azoarcus sp. were found as the most abundant representatives of denitrifiers.