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Politechniki Gdańskiej

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  • Joints Of Steel Sandwich Structures
    • Janusz Kozak
    2021 Pełny tekst Polish Maritime Research

    Steel sandwich structures are perceived as alternatives to single-skin welded structures in the shipbuilding industry due its advantages like significant reduction of mass in relation to typical single skin structure. However, beside problems with their strength properties itself, applications in real structures requires of solving the problem of joining, both for connection sandwich to sandwich as well as sandwiches to single-shell structures. Proper design of joints is connected with some factors like lack of attempt to interior of panel, introduction of additional parts and welds with completely different stiffness. In the paper the results of laboratory fatigue tests of selected joints as well as numerical calculation of stresses for different kind of joints of sandwich structures are presented. As result of calculations optimisation of geometry for selected joints is performed.

  • Józef Kostro – absolwent Politechniki Gdańskiej zamordowany w obozie koncentracyjnym w Auschwitz
    • Witold Parteka
    2021 Pismo PG

    Artykuł przedstawia sylwetkę Józefa Kostro. W październiku 2020 roku do zbiorów Sekcji Historycznej PG przekazano materiały dotyczące inżyniera dyplomowanego Józefa Kostro – studenta przedwojennej Politechniki Gdańskiej (Technische Hochschule der Freien Stadt Danzig) i absolwenta Wydziału Budowy Maszyn z 1930 roku. Ofiarodawcą jest prof. Ludwik Kostro – syn, emerytowany profesor Uniwersytetu Gdańskiego, filozof, fizyk, biblista, wykładowca gdańskich uczelni. Materiał dokumentacyjny jest różnorodny i bardzo wartościowy.

  • Jubileusz 75-lecia powstania Politechniki Gdańskiej analiza publikacji pracowników Politechniki Gdańskiej (1945–2019)
    • Beata Adamczak
    • Anna Wałek
    2021 Pełny tekst Pismo PG

    W niniejszym artykule zaprezentowano szczegółową analizę bibliometryczną publikacji pracowników Politechniki Gdańskiej w latach 1945–2019.

  • Jubileusz Stowarzyszenia Inżynierów i Techników Polskich "Polonia Technica"
    • Adam Barylski
    2021 Pismo PG

    Przedstawiono przebieg uroczystości 80 lecia działalności Stowarzyszenia Inżynierów i Techników Polskich "Polonia Technica" w USA. Obchody rocznicowe odbyły się 23 maja 20121 roku w Nowym Jorku. Założycielem Stowarzyszenia był Walery Starczewski, absolwent Politechniki Gdańskiej z roku 1926.

  • Jumping Wave Characteristic during Low Plasticity Burnishing Process
    • Stefan Dzionk
    • Michał Dobrzyński
    • Bogdan Ścibiorski
    2021 Pełny tekst Materials

    During the low plasticity burnishing process of soft materials such as carbon steel with a hardness of up to 40 HRC (Rockwell grade) a raised structure of the material known as the Jumping Wave forms in front of the tool roll. This phenomenon significantly disturbs the burnishing process, but is very poorly described in the literature. This article presents studies of this phenomenon on the example of burnished 1.0562 steel. The research concerns the changes in the surface structure of the processed material as well as changes in the structure of the material during this process. The research shows changes in the geometric structure of the surface made in the 3D system and their parametric description. Moreover, the work presents an analysis of the metallographic structure in the tool zone. The research showed occurrence of material slippages in the wave in front of the tool, which creates an additional structure on the surface. These tests make it possible to better understand the process of changes that take place in the surface layer of the processed element in the low plasticity burnishing process.

  • Just look at to open it up: A biometric verification facility for password autofill to protect electronic documents
    • Maciej Smiatacz
    • Bogdan Wiszniewski
    2021 Pełny tekst MULTIMEDIA TOOLS AND APPLICATIONS

    Electronic documents constitute specific units of information, and protecting them against unauthorized access is a challenging task. This is because a password protected document may be stolen from its host computer or intercepted while on transfer and exposed to unlimited offline attacks. The key issue is, therefore, making document passwords hard to crack. We propose to augment a common text password authentication interface to encrypted documents with a biometric facial identity verification providing highly personalized security mechanism based on pseudo-identities. In consequence the encrypted document can be unlocked with the legitimate user’s face, while for everyone else stays encrypted with a hard to crack text password. This paper makes two contributions: (1) The proposed scheme enables password autofill without referring to any external service, which significantly limits the possibilities of an attack by adversaries when opening, reading and editing the protected document, (2) By the adoption of biometric verification techniques enabling fine-tuning of false acceptance and false rejection rates, it provides for responsible adaptation to users.

  • Justifying the prolongation of the service life of the bearing structure of a tank car when using Y25 bogies
    • Oleksij Fomin
    • Alyona Lovska
    • Kseniia Ivanchenko
    • Ievgen Medvediev
    2021 Pełny tekst Eastern-European Journal of Enterprise Technologies [ Восточно-Европейский журнал передовых технологий ]

    This paper substantiates the use of Y25 bogies under tank cars in order to prolong their service life. The reported study has been carried out for a tank car with rated parameters, as well as the actual ones, registered during full-scale research. Mathematical modeling was performed to determine the basic indicators of the tank car dynamics. The differential equations of motion were solved by a Runge-Kutta method using the Mathcad software package (USA). It was established that the use of Y25 bogies under a tank car with rated parameters could reduce the acceleration of its bearing structure by almost 39 % compared to the use of standard 18-100 bogies. Applying the Y25 bogies under a tank car with the actual parameters reduces the acceleration of its load-bearing structure by almost 50 % compared to the use of standard 18‒100 bogies. The derived acceleration values were taken into performed using the SolidWorks Simulation software (France). The resulting stress values are 18 % lower than the stresses acting on the load-bearing structure of a tank car equipped with 18-100 bogies. For the load-bearing structure of a tank car with the actual parameters, the maximum equivalent stresses are 16 % lower than the stresses when the 18‒bogies are used. The design service life of the load-bearing structure of a tank car was estimated taking into consideration the use of Y25 bogies. The calculations showed that the design service life of the bearing structure of a tank car equipped with Y25 bogies is more than twice as high as that obtained for 18-100 bogies. The study reported here would contribute to compiling recommendations for prolonging the service life of the load-bearing structures of tank cars

  • KAMIŃSKI W.: Modelowanie przemieszczeń pionowych mieszaną, ortogonalną metodą najmniejszych kwadratów (Mixed Total Least Squares)
    • Waldemar Kamiński
    2021 Inżynieria Morska i Geotechnika

    Problematyka modelowania przemieszczeń pionowych standardową metodą najmniejszych kwadratów i mieszaną ortogonalną metodą najmniejszych kwadratów. Przykłady praktycznych obliczeń na rzeczywistych i symulowanych wynikach obserwacji.

  • Keystroke Dynamics Patterns While Writing Positive and Negative Opinions
    • Agata Kołakowska
    • Agnieszka Landowska
    2021 Pełny tekst SENSORS

    This paper deals with analysis of behavioural patterns in human–computer interaction. In the study, keystroke dynamics were analysed while participants were writing positive and negative opinions. A semi-experiment with 50 participants was performed. The participants were asked to recall the most negative and positive learning experiences (subject and teacher) and write an opinion about it. Keystroke dynamics were captured and over 50 diverse features were calculated and checked against the ability to differentiate positive and negative opinions. Moreover, classification of opinions was performed providing accuracy slightly above the random guess level. The second classification approach used self-report labels of pleasure and arousal and showed more accurate results. The study confirmed that it was possible to recognize positive and negative opinions from the keystroke patterns with accuracy above the random guess; however, combination with other modalities might produce more accurate results.

  • Kinetic analysis of the reduction of a ternary system of Bi, Sb and Te oxides by hydrogen for BiSbTe3 synthesis
    • Bartosz Trawiński
    • Bogusław Kusz
    2021 Pełny tekst THERMOCHIMICA ACTA

    Reduction in a hydrogen atmosphere of Bi2O3, Sb2O3 and TeO2 mixes oxides for the synthesis of BiSbTe3 was analysed. The reduction reactions of Sb2O3 and Sb2O4 oxides, as well as Bi2O3+Sb2O3 and Sb2O3+3TeO2 mix- tures, were also evaluated. The reduction of Sb2O4 is investigated for the first time. The reactions of the mixed oxides systems also were not the subject of research so far despite being used for synthesis of the (Bi,Sb)2Te3 material. The study comprised of kinetic analysis of TGA curves performed with non-parametric and iso- conversional methods. Insight into powders’ structure during the process was taken to identify processes taking place. The results show, that Sb2O3 present in the reduced oxidizes to Sb2O4. This redox process between Sb oxide and another oxide takes place directly. The self-heating effect caused by elemental tellurium is diminished in the presence of Bi, because Bi-Te phases decrease the content of the elemental Te.

  • Kinetics of the Organic Compounds and Ammonium Nitrogen Electrochemical Oxidation in Landfill Leachates at Boron-Doped Diamond Anodes
    • Barbara Wilk
    • Małgorzata Szopińska
    • Aneta Łuczkiewicz
    • Michał Sobaszek
    • Ewa Siedlecka
    • Sylwia Fudala-Książek
    2021 Pełny tekst Materials

    Electrochemical oxidation (EO) of organic compounds and ammonium in the complex matrix of landfill leachates (LLs) was investigated using three different boron-doped diamond electrodes produced on silicon substrate (BDD/Si)(levels of boron doping [B]/[C] = 500, 10,000, and 15,000 ppm—0.5 k; 10 k, and 15 k, respectively) during 8-h tests. The LLs were collected from an old landfill in the Pomerania region (Northern Poland) and were characterized by a high concentration of N-NH4+ (2069 ± 103 mg·L−1), chemical oxygen demand (COD) (3608 ± 123 mg·L−1), high salinity (2690 ± 70 mg Cl−·L−1, 1353 ± 70 mg SO42−·L−1), and poor biodegradability. The experiments revealed that electrochemical oxidation of LLs using BDD 0.5 k and current density (j) = 100 mA·cm−2 was the most effective amongst those tested (C8h/C0: COD = 0.09 ± 0.14 mg·L−1, N-NH4+ = 0.39 ± 0.05 mg·L−1). COD removal fits the model of pseudo-first-order reactions and N-NH4+ removal in most cases follows second-order kinetics. The double increase in biodegradability index—to 0.22 ± 0.05 (BDD 0.5 k, j = 50 mA·cm−2) shows the potential application of EO prior biological treatment. Despite EO still being an energy consuming process, optimum conditions (COD removal > 70%) might be achieved after 4 h of treatment with an energy consumption of 200 kW·m−3 (BDD 0.5 k, j = 100 mA·cm−2).

  • Klasyfikacja aktywności kory wzrokowej za pomocą elektroencefalografu
    • Jakub Atroszko
    2021

    W niniejszej pracy została przedstawiona metodologia konstrukcji i oceny systemu cyfrowego automatycznie klasyfikującego dane pochodzące z elektroencefalografu. Opracowana procedura badawcza pozwoliła na przetestowanie rozwiązania na różnych osobach, w różnym wieku, o różnych porach dnia, z wykorzystaniem różnych konfiguracji urządzeń i modeli zjawiska. Uzyskano stuprocentową skuteczność automatycznego rozpoznania stanu spoczynkowego kory wzrokowej. Architektura rozwiązania została oparta o algorytm maszyny wektorów nośnych, a także wektorowe reprezentacje aktywności mózgu utworzone z wykorzystaniem szybkiej transformacji Fouriera.

  • KLASYFIKACJA EMOCJI W MUZYCE FILMOWEJ Z WYKORZYSTANIEM TESTÓW SUBIEKTYWNYCH
    • Tomasz Ciborowski
    • Szymon Reginis
    • Adam Kurowski
    • Dawid Weber
    • Bożena Kostek
    2021 Pełny tekst

    Celem referatu było przedstawienie testów odsłuchowych, w których zadaniem osób ankietowanych było przypisanie danego fragmentu muzycznego do odpowiedniej klasy emocji. Kolejne kroki eksperymentu obejmowały wybór muzyki filmowej do testów (baza Epidemic Sound), przygotowanie założeń ankiety oraz modelu emocji wykorzystywanych w testach odsłuchowych, jak również konstrukcj ˛e ankiety. Ankieta została zrealizowana za pomoc ˛a formularzy Google. W ramach analizy wyników testów odsłuchowych w pierwszej kolejności sprawdzone zostały korelacje pomi ˛edzy parami klas emocji przypisanych do katalogów utworów w bazie Epidemic Sound. Nast ˛epnie zmapowano uzyskane wyniki ankiety na wykorzystany model, który zawiera emocje odniesienia (autorski model). W referacie zawarte też zostały histogramy zawieraj ˛ace przykłady list rankingowych przypisań kolorów do emocji. Przedstawiony również został zarys dalszych eksperymentów.

  • KLASYFIKACJA STANU TECHNICZNEGO UKŁADU WTRYSKOWEGO SILNIKA Z ZAPŁONEM SAMOCZYNNYM NA PODSTAWIE POMIARU SKŁADU SPALIN
    • Jacek Rudnicki
    • Jakub Bujczenko
    2021 Pełny tekst Journal of Polish CIMEEAC

    Artykuł przedstawia wyniki empirycznej weryfikacji hipotezy pozwalającej na opracowanie sprzętowo – programowego klasyfikatora stanu technicznego układu wtryskowego silnika z zapłonem samoczynnym. Pozytywna weryfikacja wspomnianej hipotezy, która wiąże przebieg procesu spalania, skład chemiczny spalin oraz wybrane stany niesprawności technicznej układu wtryskowego pozwoliła na przedstawienie koncepcji klasyfikatora w rozpatrywanym zbiorze klas stanu układu wtryskowego.

  • Klasyfikacja tekstu przy użyciu grafowych sieci neuronowych
    • Robert Benke
    2021

    Współczesnym algorytmom analizy tekstu wciąż daleko do ludzkiego poziomu jego zrozumienia. Jednym z wyzwań jest znajdowanie przez maszynę związków pomiędzy odległymi fragmentami tekstu. Próbą rozwiązania tego problemu są grafowe reprezentacje tekstu, które bardzo dobrze sprawdzają się w przedstawianiu złożonych zależności. W tekście opisane zostały dwie metody grafowej reprezentacji tekstu oraz algorytm grafowych konwolucyjnych sieci neuronowych.

  • Klasyfikator Adaboost w detekcji i rozpoznawaniu obiektów graficznych
    • Jerzy Dembski
    2021

    W pracy opisano metode Adaboost w zastosowaniu do detekcji obiektów graficznych, takich jak twarze lub rozpoznawania np. osób na podstawie obrazu twarzy. Przedstawiono podstawy algorytm, wersje kaskadowa, schemat przepływu danych i sterowania w zadaniu detekcji twarzy oraz sposoby adaptacji tej metody do problemów wieloklasowych. Opisano równiez zbiory cech obrazów, takie jak HAAR, LBP czy HOG stosowane w zadaniach detekcji i rozpoznawania obiektów graficznych.

  • Knowledge risks in organizations – Insights from companies
    • Małgorzata Zięba
    • Susanne Durst
    • Martyna Gonsiorowska
    • Zeynaddin Zralov
    2021 Pełny tekst

    Purpose: Knowledge risks are increasingly becoming a great challenge to a variety of organizations. At the same time, academic research on such types of risks, their consequences, and potential ways of overcoming them is still scarce and fragmented. To fill this gap, the paper aims to find out do companies manage their knowledge risks, what are the possible knowledge risks they face and have they observed an increase of knowledge risks during the COVID-19 pandemic. The paper is aimed to present insights on different types of knowledge risks that organizations face, and the ways organizations handle them. The paper also proposes some potential countermeasures organizations might use to mitigate the consequences of knowledge risks. Methodology: The study presents the results of a quantitative survey performed among 60 professionals dealing with management and knowledge risks in organizations. In the study, the authors also have examined what tools and methods are used to manage these risks. The study also explores the level of readiness organizations have to address potential knowledge risks. Findings: The theoretical study has allowed us to identify a variety of knowledge risks, which can bear severe consequences for organizations, such as knowledge loss, knowledge leaking, knowledge hiding, or risks related to cybercrime. All these risks may potentially reduce the productivity in organizations, thus leading to the degradation of organizational performance. Research limitations: Research results are limited to the convenience sample that was selected for the study and thus may not give a comprehensive overview of the state of the art. Practical implications: The study provides useful insights for managers and owners of organizations in need of dealing with the knowledge risks in their organizations. The paper is enriched with a number of sample solutions that they may apply for the sake of their organization. Originality/value: The paper lays the ground for a better understanding of the knowledge risks that organizations need to face nowadays. As such, the paper offers food for thought for researchers dealing with the topic of knowledge risks, knowledge management, and organizational risk management in general.

  • Knowledge Risks in the COVID-19 Pandemic
    • Małgorzata Zięba
    • Susanne Durst
    • Martyna Gonsiorowska
    2021 Pełny tekst

    This conceptual paper aims to identify, present, and analyse potential knowledge risks organizations face in external and dynamic crises such as the COVID-19 pandemic. Until only recently, many researchers and practitioners have perceived knowledge primarily as something positive. This view has changed recently with a growing number of studies highlighting risks related to knowledge. The on-going COVID-19 pandemic can be seen as an additional triggering point which has brought several new knowledge risks. Research on knowledge risks, their consequences and potential ways of handling them is still only in its beginning and consequently rather fragmented. To address this situation, this paper is aimed to provide some theoretical insights into knowledge risks and their possible implications organizations are exposed to in an external and dynamic crisis such as the COVID-19 crisis. To reach this aim, this paper presents a continuation of the research by Durst and Zieba from 2018 related to knowledge risks and their potential outcomes. This present study reviewed the up-dated literature on knowledge risks and uses the taxonomy proposed in the paper by Durst and Zieba to identify and analyse knowledge risks organizations are exposed to in the COVID-19 pandemics. Hence, the paper does not only offer fresh food for thought for researchers dealing with the topic of knowledge risks in the COVID-19 crisis and ways of handling them.

  • Knowledge Sharing in the COVID-19 Era of Remote Teaching: What Can Academia Learn from Business?
    • Krzysztof Zięba
    2021 Pełny tekst

    Purpose: The aim of this paper is to investigate how universities may benefit from experiences of businesses that were also forced to use remote forms of business operations. Methodology: The paper uses in-depth interviews to explore the possibilities of knowledge sharing improvements at the university-level teaching, based on the experiences elicited in the business sector. The theoretical sampling was used to find informants familiar with both transition to remote teaching and shift to online business operations forced by the COVID-19 pandemic. Findings: Interviews were conducted with experienced managers participating in an MBA programme. During the outburst of the COVID-19 pandemic the programme has been switched to a remote mode. At the same time, the interviewed managers had to cope with the transition to remote mode at work. Their work-related ordeals were contrasted and compared with their university-related experiences regarding knowledge sharing. Research limitations: This paper is of an exploratory character. The triangulation of findings presented here is limited. The sample consists of participants of one MBA programme only, hence the conclusions cannot be generalised. At this stage the paper may serve as a basis for further development. Practical implications: The paper presents possible improvements to be introduced by academia in the remote mode teaching. Business sector and especially large businesses may offer experience-based solutions that allow to boost knowledge sharing processes among students and increase the efficiency of knowledge sharing between teachers and students. Originality/value: The topic of the paper is very up-to-date and of considerable significance. Knowledge sharing processes at the university-level teaching have been significantly distorted by the COVID-19 pandemic outburst. Using experiences from the business sector can be very helpful in this regard.

  • Komputer w labiryncie
    • Michał Gleba
    • Grzegorz Godycki Ćwirko
    • Maryia Mankevich
    • Joanna Raczek
    2021 Pełny tekst Programista Junior

    Programiści piszą programy, które potrafią robić wiele różnych rzeczy: odtwarzać filmy, prognozować pogodę, pomagać w nauce języków obcych czy matematyki. Ale czy wiesz, że można zaprogramować komputer tak, aby tworzył labirynty? W dodatku takie, które zawierają tajne informacje!