Repozytorium publikacji - Politechnika Gdańska

Current harmonic controller in multiple reference frames for series active power filter integrated with 18-pulse diode rectifier

• Wojciech Śleszyński
• Artur Cichowski
• Piotr Mysiak

2018 Pełny tekst Bulletin of the Polish Academy of Sciences-Technical Sciences

The paper presents the control system and selected results of experimental tests of the AC/DC power converter consisting of an 18-pulse diode rectifier based on coupled reactors and a serial active power filter. Proportional integral controllers with decoupling components are implemented in multiple reference frames for selective line current harmonic suppression. The regulator is provided with a backtracking anti-windup mechanism of sorts in which a signal proportional to the saturated control reference is subtracted from the error signal in each reference frame. The fundamental harmonic filter based on the DFT algorithm with phase correction is used for grid synchronization and current harmonic detection. Three configurations of the 15 kVA converter were tested experimentally and then compared: the 18-pulse diode rectifier with and without an additional grid reactor, and the rectifier integrated with an active power filter. The applied control method of active filter significantly reduces harmonic distortion and unbalance of the grid current, which is particularly advantageous under non-ideal supply voltage and low loads conditions.

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Cybersecurity and Privacy in Standards for Smart Grids – a Comprehensive Survey

• Rafał Leszczyna

2018 Pełny tekst COMPUTER STANDARDS & INTERFACES

Resilient information and communications technologies are a prerequisite for reliable operation of smart grid. In recent years, many standards for the new form of electricity network have been proposed, which results in operators and other smart grid stakeholders having difficulties in finding the documents which can be related to their particular problems. The purpose of this paper is to bring in all smart grid standards that describe cybersecurity issues and to provide the information regarding their contents. In order to achieve this goal, a systematic study was conducted that led to the identification of thirty six publications on security and eleven on privacy. The details of the research method and the standards’ selection and evaluation criteria are presented.

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Czekaj - obraz

• Krzysztof Wróblewski

2018

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Cztery algorytmy które wstrząsnęły światem. Część I: Rys historyczny

• Marek Kubale

2018 Pismo PG

Opracowanie jest pierwszym fragmentem 3-częściowego szkicu popularnonaukowego poświęconego najważniejszym osiągnięciom w dziedzinie algorytmiki teoretycznej. Wprowadzono w w arkana złożoności obliczeniowej i sztuki programowania komputerów.

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Czujniki gazów wykorzystujące polimery przewodzące

• Katarzyna Dunst

2018

Celem rozprawy doktorskiej jest zbadanie możliwości zastosowania polimerów przewodzących w czujnikach gazów środowiskowych .

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Czy istnieje idealny marker zanieczyszczeń środowiska wodnego ? Cz. II. Alkaloidy, farmaceutyki oraz jodowane środki kontrastowe jako potencjalne markery z grupy nowo pojawiających się zanieczyszczeń

• Dagmara Kempińska-Kupczyk
• Jacek Namieśnik
• Agata Kot-Wasik

2018 Analityka: Nauka i Praktyka

Każdego dnia do środowiska wodnego wprowadzanych jest mnóstwo zanieczyszczeń, pochodzących z odpadów rolniczych i przemysłowych oraz ścieków komunalnych. Nieskuteczny proces ich usuwania podawany jest jako główny powód pogarszania się jakości środowiska wodnego. Wśród związków przedostających się do ekosystemów wodnych coraz większym zainteresowaniem cieszą się te należące do grupy nowo pojawiających się zanieczyszczeń. Są to m.in. alkaloidy, farmaceutyki i jodowane środki kontrastowe. Do określenia zawartości tych substancji w środowisku wodnym z powodzeniem wykorzystuje się techniki chromatograficzne. Pomimo, że wykrywane stężenia nowo pojawiających się zanieczyszczeń są stosunkowo niskie, niepodatność wielu tych substancji na procesy oczyszczania, trwałość w środowisku wodnym oraz regularne dostarczanie do ekosystemu sprawia, iż wybrane związki mogą być wykorzystywane jako markery zanieczyszczenia środowiska wodnego.

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Czy istnieje idealny wskaźnik zanieczyszczeń środowiska wodnego? Cz. III. Składniki środków higieny osobistej, substancje intensywnie słodzące oraz niedozwolone substancje odurzające jako potencjalne markery z grupy nowo pojawiających się zanieczyszczeń

• Dagmara Kempińska-Kupczyk
• Jacek Namieśnik
• Agata Kot-Wasik

2018 Analityka: Nauka i Praktyka

W wyniku działalności człowieka generowane jest wiele organicznych substancji należących m.in. do grupy nowo pojawiających się zanieczyszczeń. Wśród nich coraz większym zainteresowaniem cieszą się substancje intensywnie słodzące, składniki środków higieny osobistej oraz niedozwolone substancje odurzające, które są nie tylko oznaczane w wodach środowiskowych, ale także w pitnych. Do określenia ich zawartości w środowisku wodnym z powodzeniem wykorzystuje się techniki chromatograficzne. Pomimo, że wykrywane stężenia słodzików, narkotyków i składników środków higieny osobistej są stosunkowo niskie, to niepodatność wielu z nich na procesy oczyszczania, stałe wprowadzanie ich do środowiska oraz trwałość w ekosystemie wodnym, powoduje iż mogą być one stosowane jako markery.

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Czy społeczna odpowiedzialność uniwersytetu może być bardziej odpowiedzialna? Szanse wynikające z koopetycji uczelni

• Elżbieta Karwowska
• Krzysztof Leja

2018 Pełny tekst e-mentor

Współczesna uczelnia, prowadząc działalność dydaktyczną i badawczą, pełni ważną rolę wobec społeczeństwa. W opracowaniach naukowych dotyczących problematyki społecznej odpowiedzialności uczelni poruszane są następujące jej aspekty: społeczny, ekonomiczny, środowiskowy i edukacyjny, zarówno na poziomie instytucjonalnym, jak i systemowym. Autorzy artykułu dostrzegli natomiast brak publikacji dotyczących istotnego elementu społecznej odpowiedzialności uczelni, jakim jest skłonność i zdolność do współkonkurowania, zwanego w literaturze również „koopetycją”, a także „kooperencją”. Zjawisko koopetycji – dobrze znane w biznesie – zdaniem autorów opracowania, można adoptować na grunt akademicki, gdyż uczelnie mogą tworzyć alianse wiedzy, konkurując o zasoby, a równocześnie ze sobą współpracując. W artykule poddano analizie sześć studiów przypadku społecznie odpowiedzialnych uczelni na świecie, podjęto próbę rozszerzenia badań uzupełniając je o uwagi na temat znaczenia współkonkurowania, oraz starając się wskazać, że wzbogaca ono odpowiedzi na pytania: względem kogo uczelnie są społecznie odpowiedzialne?; w jakich warunkach uczelnie stają się społecznie odpowiedzialne?; a także jakie praktyki z zakresu społecznej odpowiedzialności stosują? W końcowej części opracowania autorzy zwrócili uwagą na fakt, że koopetycja uczelni może poprzedzać ich konsolidację, która jest wyraźnie zauważalna wśród uczelni europejskich. Ta konstatacja, zdaniem autorów, jest również argumentem za tym, aby rozważania nad społeczną odpowiedzialnością uczelni poszerzyć o szanse wynikające z możliwości współkonkurowania (koopetycji) uczelni.

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Czynniki kształtujące środowisko pacjenta w szpitalu

• Jacek Poplatek

2018

Szpital jest miejscem szczególnym – z założenia przebywają w nim osoby, znajdujące się w sytuacji niekomfortowej. Możliwości adaptacji w nowym środowisku u osób chorych, osłabionych lub osób z niepełnosprawnościami są znacząco obniżone, a przecież szpital należy do budynków o najbardziej skomplikowanej strukturze funkcjonalno-przestrzennej. Stan emocjonalny pacjenta w środowisku szpitalnym jest uzależniony od relacji z lekarzami i personelem medycznym, od stosowanych procedur leczenia i postępowania oraz od jakości otaczającej przestrzeni, będącej wynikiem kreacji architektonicznej. Badania naukowe potwierdzają, że istnieje ścisły związek pomiędzy przestrzenią szpitala, jego wnętrzem (designem szpitala), a stanem emocjonalnym pacjenta oraz relacjami między pacjentem i personelem medycznym. Dlatego niezwykle odpowiedzialna jest rola architekta – kreatora relacji między pacjentem, a środowiskiem szpitala. W wyniku rozwoju technologii medycznych i sposobów leczenia w drugiej połowie XX wieku szpital stał się wydajną "maszyną" do leczenia pacjenta. Medykalizacja procedur medycznych pozwalała na skuteczne leczenie pacjentów przy jednoczesnym eliminowaniu zakażeń wewnątrzszpitalnych, jednak w efekcie pacjent stał się przedmiotem zależnym od medycznej procedury. Obecnie lekarze, instytucje i organizacje związane z ochroną zdrowia oraz architekci dostrzegają, że szpital musi łączyć funkcję diagnostyki i leczenia, eliminowania zakażeń wewnątrzszpitalnych z jednoczesną dbałością o dobro pacjenta także w sensie jego stanu emocjonalnego. W rozdziale analizuje się zasadnicze czynniki, mające wpływ na sytuację pacjenta w szpitalu oraz aktualne tendencje w projektowaniu obiektów architektury ochrony zdrowia w krajach rozwiniętych oraz w warunkach polskich.

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DAB+ Coverage Analysis: a New Look at Network Planning using GIS Tools

• Marek Kulawiak
• Przemysław Falkowski-Gilski
• Marcin Kulawiak

2018

For many years, the matter of designing a transmitter network, optimized for best signal coverage, has been a subject of intense research. In the last decade, numerous researchers and institutions used GIS and spatial analysis tools for network planning, especially transmitter location. Currently, many existing systems operate in a strictly two-dimensional manner, not taking into account the three-dimensional nature of the analyzed landscape. Moreover, systems that utilize a digital terrain model in their analyzes also resort to a basic viewshed model. Due to recent adoption of mobile LiDAR scanners, the number of three-dimensional terrain information, including location and height of natural and man-made objects, is growing rapidly. In this paper, we propose a novel web-based GIS tool for three-dimensional simulation and analysis of radio signal coverage, dedicated to DAB+ terrestrial broadcasting network planning.

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Damage Control in Warships

• Bartłomiej Jakus
• Zbigniew Korczewski
• Waldemar Mironiuk
• Jan Szyszka
• Ryszard Wróbel

2018

As a result of dynamic quantitative and qualitative developments in the maritime industry its participants face harder and harder challenges pertaining to safety of ships and navigation. Practice has shown that even very well organised fleets are harassed by emergencies and accidents that can be neither predicted nor absolutely avoided. In order to counter the occuring emergencies and accidents, and to minimize their effects damage control system is organized on board ships. Damage control is one of the most vital elements to preserve the ship's vitality (survivability). This Course Book is composed of thwo parts and covers the complete list of topics dealing with damage control in ships. Part One of the Course Book: "Damage Control in Warships" includes seven chapters discussing the most relevant topics in damege control and in preservation of the ship's vitality. Adequate understanding and assimilation of issues contained in the Book require that students represent general academic knowledge of mathematics, ship theory and naval construction.

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Damage Imaging in Lamb Wave-Based Inspection of Adhesive Joints

• Magdalena Rucka
• Erwin Wojtczak
• Jacek Lachowicz

2018 Pełny tekst Applied Sciences-Basel

Adhesive bonding has become increasingly important in many industries. Non-destructive inspection of adhesive joints is essential for the condition assessment and maintenance of a structure containing such joints. The aim of this paper was the experimental investigation of the damage identification of a single lap adhesive joint of metal plate-like structures. Nine joints with different defects in the form of partial debonding were considered. The inspection was based on ultrasonic guided wave propagation. The Lamb waves were excited at one point of the analyzed specimen by means of a piezoelectric actuator, while the guided wave field was measured with the use of a laser vibrometer. For damage imaging, the recorded out-of-plane vibrations were processed by means of the weighted root mean square (WRMS). The influence of different WRMS parameters (i.e., the time window and weighting factor), as well as excitation frequencies, were analyzed using statistical analysis. The results showed that two-dimensional representations of WRMS values allowed for the identification of the presence of actual defects in the adhesive film and determined their geometry.

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Damped forced vibration analysis of single-walled carbon nanotubes resting on viscoelastic foundation in thermal environment using nonlocal strain gradient theory

• Mohammad Malikan
• Van Bac Nguyen
• Francesco Tornabene

2018 Pełny tekst Engineering Science and Technology-An International Journal-JESTECH

In this paper, the damped forced vibration of single-walled carbon nanotubes (SWCNTs) is analyzed using a new shear deformation beam theory. The SWCNTs are modeled as a flexible beam on the viscoelastic foundation embedded in the thermal environment and subjected to a transverse dynamic load. The equilibrium equations are formulated by the new shear deformation beam theory which is accompanied with higher-order nonlocal strain gradient theory where the influences of both stress nonlocality and strain gradient size-dependent effects are taken into account. In this new shear deformation beam theory, there is no need to use any shear correction factor and also the number of unknown variables is the only one that is similar to the Euler-Bernoulli beam hypothesis. The governing equations are solved by utilizing an analytical approach by which the maximum dynamic deflection has been obtained with simple boundary conditions. To validate the results of the new proposed beam theory, the results in terms of natural frequencies are compared with the results from an available well-known reference. The effects of nonlocal parameter, half-wave length, damper, temperature and material variations on the dynamic vibration of the nanotubes, are discussed in detail.

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Data augmentation for improving deep learning in image classification problem

• Agnieszka Mikołajczyk
• Michał Grochowski

2018

These days deep learning is the fastest-growing field in the field of Machine Learning (ML) and Deep Neural Networks (DNN). Among many of DNN structures, the Convolutional Neural Networks (CNN) are currently the main tool used for the image analysis and classification purposes. Although great achievements and perspectives, deep neural networks and accompanying learning algorithms have some relevant challenges to tackle. In this paper, we have focused on the most frequently mentioned problem in the field of machine learning, that is the lack of sufficient amount of the training data or uneven class balance within the datasets. One of the ways of dealing with this problem is so called data augmentation. In the paper we have compared and analyzed multiple methods of data augmentation in the task of image classification, starting from classical image transformations like rotating, cropping, zooming, histogram based methods and finishing at Style Transfer and Generative Adversarial Networks, along with the representative examples. Next, we presented our own method of data augmentation based on image style transfer. The method allows to generate the new images of high perceptual quality that combine the content of a base image with the appearance of another ones. The newly created images can be used to pre-train the given neural network in order to improve the training process efficiency. Proposed method is validated on the three medical case studies: skin melanomas diagnosis, histopathological images and breast magnetic resonance imaging (MRI) scans analysis, utilizing the image classification in order to provide a diagnose. In such kind of problems the data deficiency is one of the most relevant issues. Finally, we discuss the advantages and disadvantages of the methods being analyzed

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Daylighting Education in Practice Verification of a new goal within a European knowledge investigation

• Federica Giuliani
• Natalia Sokół
• Roberto Maria Lo Verso
• Federica Caffaro
• Aicha Diakite
• Raquel Viula
• Bernard Paule

2018

Two independent surveys were conducted in 2017 and in 2018 among architecture students across Europe to investigate their knowledge on daylighting and the impact of that knowledge on the visual perception of daylit spaces. A total of 600 responders were involved. This paper presents findings from the second survey, which was distributed in six European countries. Based on the findings from the first survey, a new goal was set for the second survey: to examine how daylighting knowledge may influence the visual perception of it and how the perception of a daylit space by a student population and by experts compare to each other. Three main findings were observed: i) the perceived comfort shows a better agreement with mood than with sky condition; ii) the judgments expressed by the experts and by non-experts are consistent with each other, confirming an outcome of the earlier study and iii) there is a lack of knowledge about daylighting metrics and regulations as well as a difficulty in implementing daylighting into the design process. These outcomes highlight the relevance of reconsidering the way daylighting education is delivered in current architectural programmes.

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Daytime Acute Non-Visual Alerting Response in Brain Activity Occurs as a Result of Short- and Long-Wavelengths of Light

• Kamila Łaszewska
• Goroncy Agnieszka
• Piotr Weber
• Tadeusz Pracki
• Małgorzata Tafil-klawe
• Daria Pracka
• Piotr Złomańczuk

2018 JOURNAL OF PSYCHOPHYSIOLOGY

Very recent preliminary findings concerning the alerting capacities of light stimulus with long-wavelengths suggest the existence of neural pathways other than melatonin suppression that trigger the nonvisual response. Though the nonvisual effects of light during the daytime have not been investigated thoroughly, they are definitely worth investigating. The purpose of the present study is to enrich existing evidence by describing how quantitative electroencephalography (EEG) signal analysis can give insight into the measurement of the acute nonvisual response observed in brain states generated during daytime exposure to light (when melatonin secretion is negligible). EEG changes were assessed in 19 subjects during the daytime while being exposed to both short- (blue, 72 μW/cm2) and long-wavelength (red, 18 μW/cm2) radiation. We showed that artificial light stimulus as low as 40 lux decreases the synchronization in the upper theta, lower alpha, and upper alpha EEG activity spectrum. The direction of change was consistent with an increased level of alertness. We can conclude that EEG analysis is an indicator of the acute nonvisual response to daytime light. Surprisingly, the response was more spread over the scalp during exposure to red light than to blue light. According to our study, the response to long-wavelength stimulus that inhibits sleepiness, thereby inducing alertness, also takes place at the bright part of the 24-hr day when human beings are naturally predisposed to be exposed to a high level of sunlight: between 12 and 4 PM. The absorption spectrum of the nonvisual system seems to have different characteristics than was previously suspected: it is not dominated by the short-wavelengths, but involves long-wavelengths. Since we observed the predominance of the red-light alerting effect over the blue-light in this experiment, we conclude that more than one mechanism, beyond the melatonin pathway, must be involved.

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DBpedia and YAGO as Knowledge Base for Natural Language Based Question Answering—The Evaluation

• Tomasz Maria Boiński
• Adrian Ambrożewicz

2018 Pełny tekst Advances in Intelligent Systems and Computing

The idea of automatic question answering system has a very long history. Despite constant improvement of the systems asking questions in the natural language requires very complex solutions. In this paper the DBpedia and YAGO are evaluated as a knowledge bases for simple class 1 and 2 question answering system. For this purpose a question answering system was designed and implemented. The proposed solution and the knowledge bases were evaluated and some remarks are given.

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DBpedia and YAGO Based System for Answering Questions in Natural Language

• Tomasz Maria Boiński
• Julian Szymański
• Bartłomiej Dudek
• Paweł Zalewski
• Szymon Dompke
• Maria Czarnecka

2018 Pełny tekst

In this paper we propose a method for answering class 1 and class 2 questions (out of 5 classes defined by Moldovan for TREC conference) based on DBpedia and YAGO. Our method is based on generating dependency trees for the query. In the dependency tree we look for paths leading from the root to the named entity of interest. These paths (referenced further as fibers) are candidates for representation of actual user intention. The analysis of the question consists of three stages: query analysis, query breakdown and information retrieval. During these stages the entities of interest, their attributes and the question domain are detected and the question is converted into a SPARQL query against the DBpedia and YAGO databases. Improvements to the methods are presented and we discuss the quality of the modified solution. We present a system for evaluation of the implemented methods, showing that the methods are viable for use in real applications. We discuss the results and indicate future directions of the work.

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Decentralized Microgrid Energy Management System with Market-Based Energy Trade System

• Adrian Włodarczyk
• Albert Kowalczyk
• Jarosław Tarnawski

2018

This paper presents a decentralized energy management system for a power microgrid, which integrates individual users, who own renewable energy sources and energy storages. The purpose of the system is to make optimal use of available resources to cover the electricity needs of the whole microgrid. Thanks to the energy exchange system, in addition to exchanges with the distribution network, the system also allows trades within the microgrid, between its participants. This way, users can get better offers for buying and selling energy than from the grid. The developed system uses linear optimization tasks to determine optimal power flows between microgrid's nodes. In order to do that, the system uses forecasted power generation profiles and consumer demand profiles, which come from prediction modules. Full decentralization of the system allowed for practically unlimited scalability compared to centralized systems. Decentralization also means better reliability and gives users the opportunity to make any changes to the optimizer. The system has been implemented in Python using free tools and libraries so that it can be implemented on any computer with an interpreter of that language.

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Decision support system for design of long distance heat transportation system

• Piotr Hirsch
• Michał Grochowski
• Kazimierz Duzinkiewicz

2018 ENERGY AND BUILDINGS

District Heating (DH) systems are commonly supplied using local heat sources. Nowadays, modern insulation materials allow for effective and economically viable heat transportation over long distances (over 20 km). The paper proposes a Decision Support System (DSS) for optimized selection of design and operating parameters of a long distance Heat Transportation System (HTS). The method allows for evaluation of feasibility and effectiveness of heat transportation from the considered heat sources to the given DH area. The optimized selection is formulated as the multicriteria decision-making problem. The constraints for this problem include a static HTS model, allowing considerations of the system life cycle, as well as time variability and spatial topology. Thereby, the variation of heat demand and ground temperature within the DH area, the insulation and pipe aging, as well as the terrain elevation profile are taken into account in the decision-making process. The HTS construction costs, the operating costs (pumping power), and the heat loss are considered as objective functions, while such parameters as: inner pipeline diameter, insulation thickness, temperature and pressure profiles, as well as pumping station locations are optimized during the decision-making process. Moreover, variants of pipe laying e.g. one pipeline with a larger diameter, or two parallel pipelines with smaller diameters might be considered during the optimization. The analyzed optimization problem is multicriteria, hybrid and nonlinear. The genetic solver has been proposed to solve it.

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