2018 - Repozytorium publikacji - Politechnika Gdańska

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Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads
- Monika Chmielowiec-Jablczyk
- Andreas Schubert
- Christian Kraft
- Hubert Schwarze
- Michał Wodtke
- Michał Wasilczuk
2018 Pełny tekst Lubricants
A modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions of the Reynolds equation including a cavitation model, the energy equation and the heat transfer equation are done iteratively with the finite volume method by considering a constant flow rate. Both effects—laminar/turbulent flow and centrifugal force—are considered. The calculation results are compared with measurements done for a flooded thrust bearing with nominal eight tilting pads with an outer diameter of 180 mm. The heat convection coefficients for the pad surfaces mainly influence the pad temperature field and are adjusted to the measurement results. In the following paper, the calculation results for variable space distances, influence of different parameters on the bearing behavior and operating condition at high load are presented.
Improving all-reduce collective operations for imbalanced process arrival patterns
- Jerzy Proficz
2018 Pełny tekst JOURNAL OF SUPERCOMPUTING
Two new algorithms for the all-reduce operation optimized for imbalanced process arrival patterns (PAPs) are presented: (1) sorted linear tree, (2) pre-reduced ring as well as a new way of online PAP detection, including process arrival time estimations, and their distribution between cooperating processes was introduced. The idea, pseudo-code, implementation details, benchmark for performance evaluation and a real case example for machine learning are provided. The results of the experiments were described and analyzed, showing that the proposed solution has high scalability and improved performance in comparison with the usually used ring and Rabenseifner algorithms.
Improving methods for detecting people in video recordings using shifting time-windows
- Adam Blokus
- Henryk Krawczyk
2018
We propose a novel method for improving algorithms which detect the presence of people in video sequences. Our focus is on algorithms for applications which require reporting and analyzing all scenes with detected people in long recordings. Therefore one of the target qualities of the classification result is its stability, understood as a low number of invalid scene boundaries. Many existing methods process images in the recording separately. The proposed method bases on the observation that real-life videos depict underlying continuous processes. The method is named FSA (Frame Sequence Analyzed). It is applicable for any underlying binary classification algorithm and it improves it by adding an additional result postprocessing step. The performed experiments are based on improving an established face detection algorithm, evaluated on a public dataset. The effectiveness of the FSA method is verified, acquiring very good results – improving the underlying algorithm in terms of all considered error measures. In the end, possible future improvements are discussed.
Improving the Accuracy in Sentiment Classification in the Light of Modelling the Latent Semantic Relations
- Nina Rizun
- Wojciech Waloszek
- Yurii Taranenko
2018 Pełny tekst Information
The research presents the methodology of improving the accuracy in sentiment classification in the light of modelling the latent semantic relations (LSR). The objective of this methodology is to find ways of eliminating the limitations of the discriminant and probabilistic methods for LSR revealing and customizing the sentiment classification process (SCP) to the more accurate recognition of text tonality. This objective was achieved by providing the possibility of the joint usage of the following methods: (1) retrieval and recognition of the hierarchical semantic structure of the text and (2) development of the hierarchical contextually-oriented sentiment dictionary in order to perform the context-sensitive SCP. The main scientific contribution of this research is the set of the following approaches: at the phase of LSR revealing (1) combination of the discriminant and probabilistic models while applying the rules of adjustments to obtain the final joint result; at all SCP phases (2) considering document as a complex structure of topically completed textual components (paragraphs) and (3) taking into account the features of persuasive documents’ type. The experimental results have demonstrated the enhancement of the SCP accuracy, namely significant increase of average values of recall and precision indicators and guarantee of sufficient accuracy level.
Improving the energy balance in wastewater treatment plants by optimization of aeration control and application of new technologies
- Ewa Zaborowska
- Joanna Majtacz
- Jakub Drewnowski
- Dominika Sobotka
- Hussein Al-Hazmi
- Przemysław Kowal
- Jacek Mąkinia
2018
The methods to improve the energy balance of a wastewater treatment plant (WWTP) by optimization of aeration process control and application of innovative nitrogen removal technologies were overviewed in the study. The control of aeration based on the ABAC (Ammonia-Based Aeration Control) system allows not only for significant savings in electricity consumption, but it can also increase the efficiency of the denitrification process. In addition to obtaining a shortened nitrification path, the use of the AVN (Ammonia vs. Nitrate/Nitrite) system can provide even more efficient nitrogen removal when controlling the process of conventional nitrificationdenitrification. It is expected that the future of the control systems in WWTPs belongs to smart process control systems cooperating with simulation models. The innovative technologies for nitrogen removal are based on the shortcut nitrogen removal pathways. Compared to the conventional nitrification-denitrification, the advantage of the deammonification (partial nitritation/anammox) process is the reduction of both electrical energy demand for aeration and the production of the sludge, as well as no need for the organic carbon source. The significance of pH, temperature, dissolved oxygen concentration, as well as the aeration patterns were emphasized and investigated in details by numerous researchers. The implementation of the innovative nitrogen removal technologies allows to separate organic and nitrogen waste streams and thus maximize energy capture. A study on the implementation of both the chemically enhanced primary treatment and the deammonification process in the sidestream treatment line revealed the potential for an increased biogas production in the anaerobic digester and reduction in the electric energy demand for aeration, while still maintaining the required total nitrogen effluent standard. The proposed upgrades can lead a WWTP from the energy deficit to the energy neutrality. A few WWTPs have already achieved almost 100% (or higher) electricity self-sufficiency using combined approaches and proved the usability of the innovative nitrogen removal technologies.
Improving the quality of speech in the conditions of noise and interference
- Bożena Kostek
- Krzysztof Kąkol
2018 Journal of the Acoustical Society of America
The aim of the work is to present a method of intelligent modification of the speech signal with speech features expressed in noise, based on the Lombard effect. The recordings utilized sets of words and sentences as well as disturbing signals, i.e., pink noise and the so-called babble speech. Noise signal, calibrated to various levels at the speaker's ears, was played over two loudspeakers located 2 m away from the speaker. In addition, the recording session included utterances in quiet, which constitute a reference to the received speech signal analysis with the Lombard effect. As a part of the analysis, the following parameters were examined with regard to prosody: fundamental frequency F0, formant frequencies of F1 and F2, duration of the utterance, sound intensity, etc., taking into account individual sentences, words, and vowels. The PRAAT program was used to process and analyze speech signals. Next, a method for modifying speech with the features of speech spoken in noise was proposed. Subsequent analyzes have shown that noisy speech modified by the Lombard effect features is characterized by higher values of the PESQ (perceptual evaluation of speech quality) speech quality indicator compared to noisy speech without the features incorporated.
Improving Traffic Light Recognition Methods using Shifting Time-Windows
- Adam Blokus
- Henryk Krawczyk
2018
We propose a novel method of improving algorithms recognizing traffic lights in video sequences. Our focus is on algorithms for applications which notify the driver of a light in sight. Many existing methods process images in the recording separately. Our method bases on the observation that real-life videos depict underlying continuous processes. We named our method FSA (Frame Sequence Analyzed). It is applicable for any underlying algorithm and improves it by adding an additional result post-processing step. Our experiments are based on improving a published realtime traffic light recognition algorithm. Its general description has been provided by its authors, which allowed us to create a best-effort implementation for testing. We verify the effectiveness of the FSA method on a public dataset, acquiring very good results - improving the underlying algorithm in terms of all considered error measures. In the end, conclusions and possible future improvements are discussed.
Improving voltage levels in low-voltage networks with distributed generation – case study
- Robert Kowalak
- Stanisław Czapp
2018
The use of distributed generation in low-voltage networks may cause the voltage variation in them, within the wide range. In unfavourable circumstances, the voltage may reach unacceptable values. The paper presents the effect of distributed generation on voltage levels in a selected low-voltage rural distribution network in Poland. An analysis of possible methods for improving voltage levels in this network is conducted. The most suitable method is indicated.
In Memoriam Professors Marianna Sankiewicz-Budzyński and Gustaw K.E. Budzyński - Founders of the Polish Audio Engineering
- Andrzej Czyżewski
- Bożena Kostek
2018 Pełny tekst Archives of Acoustics
Biography and scientific achievements of Professors Marianna Sankiewicz-Budzyński and Gustaw K.E. Budzyński - Founders of the Polish Audio Engineering.
In Search of Naval Beauty. Historical Study of Ship Architecture
- Elżbieta Marczak
- Patrycja Hanzel
2018
Designing ships is no mean achievement. In the old days, constructors focused on making their ships visually appealing, while paying scant regard to the living conditions of the crew. Such an approach reflected the state of the art in ship building at the time as well as the social order prevalent in those days. A breakthrough came no earlier than at the turn of the 19th / 20th centuries. The industrial revolution brought along advances in technology and contributed to greater social awareness. The living conditions for the crew and increasing numerous passengers, as well as naval aesthetics, became an area of primary concern for architects and an object of study for scientists. Professor Jan Witold Urbanowicz was the pioneer of the Polish school of ship architecture, who defined the new scientific field by elevating to first-rank importance the ship’s silhouette as well as its functional and spatial considerations throughout the shipbuilding process, from the drawing board to construction. A combination of his passion for the job and an inborn sense of aesthetics enabled the search for naval beauty to run in parallel with the development of user-friendly ship designs featuring freight and passenger vessels in civil service with comfortable working and living conditions. This article presents professor Urbanowicz’s most important achievements in ship designing: his activity as an engineer, educator and scientist as well as his thoughts about the re-definition of the discipline.
In Situ Random Microseeding and Streak Seeding Used for Growth of Crystals of Cold-Adapted beta-D-Galactosidases: Crystal Structure of betaDG from Arthrobacter sp. 32cB
- Maria Rutkiewicz-krotewicz
- Agnieszka Pietrzyk-Brzezińska
- Marta Wanarska
- Hubert Cieśliński
- Anna Bujacz
2018 Pełny tekst Crystals
There is an increasing demand for cold-adapted enzymes in a wide range of industrial branches. Nevertheless, structural information about them is still scarce. The knowledge of crystal structures is important to understand their mode of action and to design genetically engineered enzymes with enhanced activity. The most difficult task and the limiting step in structural studies of cold-adapted enzymes is their crystallization, which should provide well-diffracting monocrystals. Herein, we present a combination of well-established crystallization methods with new protocols based on crystal seeding that allowed us to obtain well-diffracting crystals of two cold-adapted beta-D-galactosidases (betaDGs) from Paracoccus sp. 32d (ParbetaDG) and from Arthrobacter sp. 32cB (ArthbetaDG). Structural studies of both betaDGs are important for designing efficient and inexpensive enzymatic tools for lactose removal and synthesis of galacto-oligosaccharides (GOS) and hetero-oligosaccharides (HOS), food additives proved to have a beneficial effect on the human immune system and intestinal flora. We also present the first crystal structure of ArthbetaDG (PDB ID: 6ETZ) determined at 1.9 Å resolution, and compare it to the ParbetaDG structure (PDB ID: 5EUV). In contrast to tetrameric lacZ betaDG and hexameric betaDG from Arthrobacter C2-2, both of these betaDGs are dimers, unusual for the GH2 family. Additionally, we discuss the various crystallization seeding protocols, which allowed us to obtain ParbetaDG and ArthbetaDG monocrystals suitable for diffraction experiments.
In vitro biodegradation of bacterial nanocellulose under conditions simulating human plasma in the presence of selected pathogenic microorganisms
- Paulina Dederko
- Edyta Malinowska-Pańczyk
- Hanna Staroszczyk
- Izabela Sinkiewicz
- Piotr Szweda
- Piotr Siondalski
2018 Pełny tekst Polimery
The Biodegradability of bacterial nanocellulose (BNC) was assessed based on a change in its properties under conditions simulating human plasma in the presence or absence of the pathogens Staphylococcus aureus, Candida albicans and Aspergillus fumigatus. It was shown that the dry mass of BNC did not change during 6 months of incubation, except for samples stored in the presence of moulds, where the dry mass reduced by 40 %. The wet mass of all BNC samples increased after 2 months of incubation. Under these conditions, the population number of microorganisms grew about 2 log cycles during the first month and maintained this level for 6 months of storage. After 1 month of storage in sterile fluids, and in the presence of bacteria or fungi, the tensile strength of BNC decreased by 60 % to 70 %.
Increasing efficiency of technological process by limiting impact of corrosive environment on operation of spiral classifiers
- Marcin Czekajło
- Krzysztof Żakowski
2018 Pełny tekst IOP Conference Series: Materials Science and Engineering
Most of the technological operations related to the preparation of the output to be enriched and to the production of the final copper concentrate take place with the use of water environment. Water management, besides using innovative technical and technological solutions, is a significant factor in the whole copper ore enrichment process. Mine water resources and surface water of the tailing pond named "Żelazny Most" are the two sources of technological water. Its physico-chemical composition is not insignificant for both the flotation process and the machinery and equipment maintenance. The concept of electrochemical protection of the spiral classifier presented in this article is the supplement and alternative for anti-corrosion protection of the machinery and equipment used in KGHM Polska Miedź S.A. Ore Enrichment Plant. The adequate appreciation of the spiral classifier characterisation and the working conditions will allow for the optimal adjustment of cathodic protection installations with the anode polarization system. Research into the development of an effective protection method will combine two complementary types of anti-corrosion protection systems, that is the passive (a protective coating) and the active (a cathodic protection). The effect of the planned research will be the evaluation of the potential possibilities of the corrosive and erosive impact limitation of the spiral classifier working condition. And, moreover, it will lead to an extension of working hours and the reduction in the costs of the technological circuit.
INCREASING POWER SUPPLY SAFETY IN THE ASPECT OF SUPPORTING THE RENEWABLE ENERGY SOURCES BY CONVENTIONAL AND VIRTUAL POWER STORES
- Damian Jakowski
- Marek Dzida
2018 Pełny tekst Polish Maritime Research
This paper presents characteristics and purposefulness of supporting the renewable energy sources (OZE) by means of energy stores. The main emphasis was placed on analysis of virtual energy stores available for implementation in Polish economy conditions. A role which management of Demand Side Response (DSR) may play in balancing Polish electric power system, is discussed. Implementation of such solutions together with conventional energy stores may significantly influence power supply safety by assuring continuity of electric power supply at an acceptable price. Involvement of electric power consumers ( DSR ) should be one of the basic solutions for power markets in Poland and Europe.
INCREASING THE COUNTRY'S SECURITY AND PUBLIC TRANSPORT ACCESSIBILITY BY CREATING A NETWORK OF SMALL AIRPORTS
- Eligiusz Mieloszyk
- Anita Milewska
- Mariusz Wyroślak
2018 Zeszyty Naukowe Akademii Sztuki Wojennej
It has been shown that by creating a network of small airports, it is possible to increase the communication accessibility of large population groups and the country's security, including safety at sea. The airports mentioned above may also be located on land considered to be weak from an engineering point of view. These include, for example, wetlands, swamps, flood embankments, poor coastal belt grounds, and reclaimed land. A quick and effective method of adapting the aforementioned grounds for locating airport infrastructure on them has been presented. It is a method of reinforcing the ground with blasting agents. This method can be successfully used in all conditions. In combat conditions, it can be used for quick construction of spare airports, additional runways or reconstruction of damaged runways. It can also be used to create a dispersed network of airports, airstrips, which is important not only from the military point of view, but also from the civil point of view.
INDICES FOR ASSESSING POTENTIAL ENVIRONMENTAL HAZARD FROM FUTURE SHIP SCRAPPING PROCESS, DETERMINABLE IN SHIP DESIGN STAGE
- Roman Liberacki
2018 Pełny tekst Polish Maritime Research
This paper shortly presents the issue of utilization of ships after their withdrawal from service. Information on number of floating units liquidated in previous years was presented. Hazards to the environment , health and life of workers employed in the Far East ship scrapping yards operating on the beaches, were indicated. Then, the most important rules which have to make the ship recycling process safe were referred to. This author proposed to supplement the rules by environmental hazard indices which would be determined already in ship design stage. According to the concept the indices should take into account amount of dangerous substances used for building the ship as well as degree of their harmfulness (weighing factors). Two approaches to the issue of determining the weighing factors were proposed: deterministic and fuzzy.
Individual Characteristics and Cognitions of Students with Different Levels of Entrepreneurial Intensity
- Paweł Ziemiański
2018 Pełny tekst HORYZONTY WYCHOWANIA
RESEARCH OBJECTIVE: The objective of the current paper is to verify in what way university students who declare high individual level of entrepreneurial intensity differ from those who are characterized by its intensity level. THE RESEARCH PROBLEM AND METHODS: A statistical analysis of obtained survey results was conducted. The group of research participants included 413 business students. Following statistical methods were used to analyze the data: internal reliability test, chi-square test of independence, independent samples t-test. THE PROCESS OF ARGUMENTATION: The line of reasoning presented in the current paper starts with the analysis of entrepreneurial intensity which, when measured on an individual level, is distinctive to people who declare a strong commitment to following an entrepreneurial career. Later the theoretical background including individual characteristics and cognitions that can potentially be prevalent among entrepreneurs is presented. RESEARCH RESULTS: It was found that groups of students who display high and low levels of entrepreneurial intensity differ significantly. These differences pertain to individual characteristics (i.e. gender), the perception of business success indicators and the perception of entrepreneurs’ environment favorability. CONCLUSIONS, INNOVATIONS, AND RECOMMENDATIONS: Obtained results allow to formulate conclusions about ways in which the development of entrepreneurial attitudes can be facilitated. Several recommendations are proposed for educators and policy makers including adopting a more fine-grained approach to supporting the emergence of entrepreneurial culture in Poland.
Indoor air quality of everyday use spaces dedicated to specific purposes—a review
- Mariusz Marć
- Monika Śmiełowska
- Jacek Namieśnik
- Bożena Zabiegała
2018 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
According to literature data, some of the main factors which significantly affect the quality of the indoor environment in residential households or apartments are human activities such as cooking, smoking, cleaning, and indoor exercising. The paper presents a literature overview related to air quality in everyday use spaces dedicated to specific purposes which are integral parts of residential buildings, such as kitchens, basements, and individual garages. Some aspects of air quality in large-scale car parks, as a specific type of indoor environment, are also discussed. All those areas are characterized by relatively short time use. On the other hand, high and very high concentration levels of xenobiotics can be observed, resulting in higher exposure risk. The main compounds or group of chemical compounds are presented and discussed. The main factors influencing the type and amount of chemical pollutants present in the air of such areas are indicated.
Inflation Forecast or Forecast(s) Targeting?
- Karolina Tura-Gawron
2018 Pełny tekst Romanian Journal of Economic Forecasting
The paper refers to L.E.O. Svensson’s concept of inflation forecast targeting (IFT) and its implementation by central banks of Sweden, Norway and the Czech Republic. The study focuses on (1) inflation forecasts published by selected central banks, i.e.headline inflation and core or monetary policy-relevant (MPR) inflation, which are made on the assumption of endogenous instrument rate, (2) one-year consumer inflation expectations, and (3) repo rate decisions. The aim of the paper is to investi gate whether MPR and core inflation forecasts (in addition to headline inflation forecasts) are us eful tools in implementing IFT. The authors take into consideration differences between fo recasts deviations from the inflation target, dependencies between forecasts and consumer inflation expectations and relationships between repo rate decisions and forecasts. The methodology used includes nonparametric tests and statistics (Sign Test, Wilcoxon Matched Pair Test, Nonparametric Correlation coefficients) and forecast errors analysis. The results are sufficiently positive to conclude that the implementation of IF T in central banking practice should be supplemented by forecasts of core inflation. The paper contributes to the literature on implementing monetary policy under the concept of IFT. It spotlights the importance of publication of core inflation forecasts that are not captured by other research undertakings, which tend to ignore the existence of them as such.
Influence of an applied bearing system on behaviour of multi-span footbridge
- Mikołaj Miśkiewicz
- Łukasz Pyrzowski
2018
The cycle overpass in Gdynia is a box structure over 300 metres long, 10-span. It was opened for bicycle traffic in the second half of 2013. At the end of its construction, there was failure due to excessive horizontal displacement of the system. A number of bearings exceeded the range of permissible transverse shifts thus it was necessary to temporarily protect the spans from slipping. The FEM analysis of the original solution and a proposal for a new bearing arrangement are presented in the article. Calculations were made based on a shell-and-beam model, reflecting the actual object accurately. The proposed new bearings system was even-tually applied to the structure.