2017 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2017

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Scalable Measurement System for Multiple Impedance Gas Sensors
- Grzegorz Lentka
2017 Full text MAPAN-Journal of Metrology Society of India
Author proposes scalable architecture of the measurement system for gas sensor with impedance dependance of the gas concentration. The main part of the system is a single-board impedance analyser. The number of analysers working in parallel can be configured according to specific application. The system is controlled by a single computer which organises the measurement cycle and store the acquired measurement data. The system is based on I2C-like interface and uses broadcast addressing to achieve parallel synchronisation and individual addressing to program individual setting and retrive the measurement data.
Scheduling of identical jobs with bipartite incompatibility graphs on uniform machines. Computational experiments
- Szymon Duraj
- Paweł Kopeć
- Marek Kubale
- Tytus Pikies
2017 Full text Decision Making in Manufacturing and Services
We consider the problem of scheduling unit-length jobs on three or four uniform parallel machines to minimize the schedule length or total completion time. We assume that the jobs are subject to some types of mutual exclusion constraints, modeled by a bipartite graph of a bounded degree. The edges of the graph correspond to the pairs of jobs that cannot be processed on the same machine. Although the problem is generally NP-hard, we show that our problem can be solved to optimality in polynomial time under some restrictions imposed on the number of machines, their speeds, and the structure of the incompatibility graph. The theoretical considerations are accompanied by computer experiments with a certain model of scheduling.
Scheduling of unit-length jobs with bipartite incompatibility graphs on four uniform machines
- Hanna Furmańczyk
- Marek Kubale
2017 Full text Bulletin of the Polish Academy of Sciences-Technical Sciences
The problem of scheduling n identical jobs on 4 uniform machines with speeds s1>=s2>=s3>=s4 is considered.The aim is to find a schedule with minimum possible length. We assume that jobs are subject to mutual exclusion constraints modeled by a bipartite incompatibility graph of degree delta. We show that the general problem is NP-hard even if s1=s2=s3. If, however, delta<5 and s1>12s2 s2=s3=s4, then the problem can be solved to optimality in polynomial time. The same algorithm returns a solution of value at most 2 times optimal provided that s1>2s2.
SDN testbed for validation of cross-layer data-centric security policies
- Konrad Wrona
- Marek Amanowicz
- Sebastian Szwaczyk
- Krzysztof Gierłowski
2017
Software-defined networks offer a promising framework for the implementation of cross-layer data-centric security policies in military systems. An important aspect of the design process for such advanced security solutions is the thorough experimental assessment and validation of proposed technical concepts prior to their deployment in operational military systems. In this paper, we describe an OpenFlow-based testbed, which was developed with a specific focus on validation of SDN security mechanisms - including both the mechanisms for protecting the software-defined network layer and the cross-layer enforcement of higher level policies, such as data-centric security policies. We also present initial experimentation results obtained using the testbed, which confirm its ability to validate simulation and analytic predictions. Our objective is to provide a sufficiently detailed description of the configuration used in our testbed so that it can be easily re-plicated and re-used by other security researchers in their experiments.
Search for the most useful geometry of an acoustic journal bearing
- Rafał Gawarkiewicz
2017 Full text TRIBOLOGIA
Computer simulations of a number of journal bearing’s geometries utilising acoustic levitation were carried out. The choice of the best geometry depended on the ability of a deformed shape, created by piezo-electric elements, to facilitate squeeze film ultrasonic levitation, and also to create three evenly distributed diverging aerodynamic gaps. Deformations of analysed variants of the bearing’s shape were generated by numerical simulations utilising the finite element method. For the chosen shapes of geometry, prototype bearings were made and their usefulness verified experimentally. As a result, the bearing with the highest load carrying capacity was identified.
Searching for Critical Conditions During Lifeboat Launching – Simulations
- Czesław Dymarski
- Paweł Dymarski
- Aleksander Kniat
2017 Full text Polish Maritime Research
The article describes numerical simulations of the process of lifeboat launching at the ship’s side. The research is aimed at finding the values of ship motion parameters which appear to be most dangerous for people in the lowered lifeboat due to the generated accelerations. The simplified model of ship hull motion adopted at this research stage bases on a superposition of harmonic motions with given amplitudes and periods in six degrees of freedom. The range of the amplitude of motion for each degree of freedom corresponds approximately to that of possible motion of the PANAMAX type ship on the Baltic sea. In total, 120 960 cases of ship hull motion were examined.
Searching for innovation knowledge: insight into KIBS companies
- Małgorzata Zięba
- Ettore Bolisani
- Marco Paiola
- Enrico Scarso
2017 Knowledge Management Research & Practice
The paper analyses the activity of research for “innovation knowledge”—here defined as knowledge that can lead to the introduction of service innovations—by Knowledge-Intensive Business Services (KIBS) companies. It proposes a classification of the possible search approaches adopted by those companies based on two dimensions: the pro-activity of search efforts and the source primarily used. Such classification is then discussed on the basis of the findings of a multiple case-study investigation involving 15 Italian and Polish KIBS companies. The study confirms that KIBS firms follow various approaches to acquire knowledge for innovation: some companies adopt a passive behaviour (i.e. innovative ideas come as a kind of side effect of their daily business activities), while others an active one (namely, they actively search for new ideas originating from various sources); some rely more on internal resources (employees, in-house R&D, internal documents, etc.), while others on external sources (clients, suppliers, service providers, universities, etc.). The results of the study have implications both for research and management that are discussed in the conclusions.
Searching for road deformations using mobile laser scanning
- Jakub Szulwic
- Paweł Tysiąc
2017 Full text MATEC Web of Conferences
Millions of people use roads every day all over the world. Roads, like many other structures, have an estimated durability. In Poland a lot of the roads were built at the turn of the 20th and 21st c., especially for light cars. Many of these roads carry traffic and heavy goods vehicles which were not predicted when the traffic was first estimated. It creates a lot of problems with technical conditions and the infrastructure must be improved. Treatments can be problematic, because restoring the original properties of the road requires workers to restrict traffic as cars may cause a lot of damage to the construction. In the article the authors present a method for estimating the condition of a road using the MLS (Mobile Laser Scanning) measurement technique. It is based on a mobile platform and equipped with the Riegl VMZ-400 scanning system. Post-processing of the data constrain to extract the scan lines and road’s condition analysis in addition to estimate its parameters. In conclusion, the authors present the advantages and disadvantages of Mobile Laser Scanning in addition to the paths. Moreover, tell the possibility of the factors determine which describe the security level of the roads.
SEDIMENT DEPOSITION IN RESERVOIRS IN URBAN BASIN
- Witold Sterpejkowicz-Wersocki
- Tomasz Kolerski
- Tadeusz Widerski
- Wojciech Szpakowski
- Michał Szydłowski
2017
In recent years Gdańsk had sustained economic and social losses due to severe flash floods coming down from moraine hills. The first flood occurred in July 2001 and the second in July 2016. Both events were caused by intense and long rainfall characterized by different from each other rain intensity in time. Among other Gdansk’s streams the Oliwski Stream has the most extended flood protection system consist of 15 small retention reservoirs. Due to its extensive flood protection system and lack of severe flood events in last years, Oliwski was not considered to require attention form the city authorities. Most of the reservoirs originate from ancient mill pounds operated in place for centuries. As a consequence of little attention, majority of reservoirs were significantly filled with sediment and in some cases shrunk considerably and become wetlands. One of the reservoirs was recently rebuild by cleaning the sediment and remodeling its artificial island, but the others were intact. During the 2016 flood, when in the Oliwski stream catchment an extraordinary daily sum of rain precipitation was recorded (170,2 mm in 16 hours, 140 mm in 8 hours), two of 15 reservoirs were breached and other two were severely damaged. It was the turning point for the city authorities, who decide to look closer on the flood management in Oliwski stream catchment. The aim of research projects was to establish technical solutions and procedures to be applied in case of risk of flooding due to heavy rain. One part of this study was bathymetric survey of all reservoirs to be included in hydraulic modeling system. The survey take place short after the flood and consist number of cross sections measured in each reservoir by using total station. In a paper the comparison of current and design bathymetry of two reservoirs is presented from which one was renovated in 2014 (Spacerowa reservoir) and the other was not cleared over the last 35 years (Kwietna reservoir). Base on the surveyed data some conclusions on sediment deposition could be stated.
Seismic pounding behavior of multi-story buildings in series considering the effect of infill panels
- Hytham Elwardany
- Ayman Seleemah
- Robert Jankowski
2017 ENGINEERING STRUCTURES
The aim of the present paper is to study the influence of the infill panels on the seismic pounding response of adjacent structures in series. The contribution of the masonry infill has been simulated using equivalent diagonal compression struts. Steel frames have been assumed to have elastic-plastic behavior with 1% linear strain hardening. The dynamic contact analysis has been utilized where contact surface model (target and contactor) has been applied without any connectors between the adjacent buildings. Nonlinear finite element analyses have been conducted on different configurations of infill distribution throughout the structures. The results of the analysis reveal that the existence of infill panels can substantially change the seismic behavior of the structures and may have a serious influence on their behavior during exposure to mutual pounding under seismic excitation. Moreover, the distribution of infill throughout the structure can significantly affect its behavior during earthquakes.
Selected acoustic images of the Gdansk Bay
- Eugeniusz Kozaczka
- Grażyna Grelowska
- Wojciech Szymczak
2017
The main goal of the paper is to describe the results of sounding the Gdansk Bay seabed by using a parametric sub-bottom profiler, multibeam echosounder and side scan sonar. Quality of dsata obtained during trials depends interalia on a proper location of antenna to reduce influence of pitch, roll and heave motions as well as ship noise.
Selected anionic and cationic surface active agents: case study on the Kłodnica sediments
- Olkowska Ewa
- Marek Ruman
- Magdalena Drąg-śmigalska
- Żaneta Polkowska
2017 Full text Limnological Review
Surface active agents (surfactants) are a group of chemical compounds, which are used as ingredients of detergents, cleaning products, cosmetics and functional products. After use, wastes containing surfactants or their degradation products are discharged to wastewater treatment plants or directly into surface waters. Due to their specific properties of SAAs, compounds are able to migrate between different environmental compartments such as soil, sediment, water or even living organisms and accumulate there. Surfactants can have a harmful effect on living organisms. They can connect with bioactive molecules and modify their function. Additionally, they have the ability to migrate into cells and cause their damage or death. For these reasons investigation of individual surfactants should be conducted. The presented research has been undertaken to obtain information about SAA contamination of sediment from the River Kłodnica catchment caused by selected anionic (linear alkylbenzene sulfonates (LAS C10-C13)) and cationic (alkylbenzyldimethylammonium (BDMA-C12-16), alkyl trimethyl ammonium (DTMA), hexadecyl piridinium chloride (HP) chlorides) surfactants. This river flows through an area of the Upper Silesia Industrial Region where various companies and other institutions (e.g. coal mining, power plants, metallurgy, hospitals) are located. To determine their concentration the following analytical tools have been applied: accelerated solvent extraction– solid phase extraction – high performance liquid chromatography – UV-Vis (anionic SAAs) and conductivity (cationic SAAs) detectors. In all sediments anionic SAAs have been detected. The concentrations of HTMA and BDMA-C16 in tested samples were higher than other cationic analytes. Generally, levels of surfactants with longer alkyl chains were higher and this observation can confirm their higher susceptibility to sorption on solid surfaces.
Selected aspects of the surface quality of the wooden elements after planing
- Michał Dobrzyński
- Kazimierz Orłowski
- Michał Biskup
2017
The quality of the surface of wooden elements, that have been planed, has got a crucial meaning in the whole production process flow, since the obtained effects affect the quality of wooden surface after painting. The emergence of defects in most cases causes need to qualify workpiece as a scrap part or additional work activity must be done. In the paper selected results of the investigation of the effect of the cutting tool wear on the surface quality of the elements after planing are presented. Research experiments were conducted on the SCM Superset Class machine tool. The elements under treatment were glulam elements of pine wood. The raw material samples 6 m long before planning operation were semi-finished also by planing. These workpieces were selected according to their moisture content, straightness, and defects typical for wooden materials. The following report presents measuring results of the surface layer condition as well as profile samples.
Selected problems of earth fault loop impedance testing in circuits fed from UPS
- Stanisław Czapp
2017 Automatyka Elektryka Zakłócenia
In the paper a principle of earth fault loop impedance testing in low voltage systems has been presented. Selected factors, influencing accuracy of the testing, are indicated. A structure of UPS of VFI-type and the problem of impedance testing in circuits with such type of UPS are discussed.
Selected Problems of Transport in Port Towns – Tri-City as an Example
- Marcin Budzyński
- Dawid Ryś
- Wojciech Kustra
2017 Full text Polish Maritime Research
Port towns are strategic places from the point of view of transport systems. They form integration junctions for various transport branches , apart from the traditional - road and railway ones , also for water( sea) transport which is active there. Moreover, air transport comes also into consideration , whose efficient functioning must be connected with good accessibility, that concerns sea transport as well. Efficient and safe servicing the ports is crucial for their functioning. Problems associated with the overloading of lorries, which leads to degradation of road surface structure , observed in Gdynia, are discussed as an example in this paper. Problems of road traffic safety (RTS) are presented in this paper on the example of Gdańsk. The two issues : the road traffic safety and road surface degradation constitute only some transport problems of port towns , but they are very important, from the point of view of their specificity, for integration junctions of all the transport branches for people and goods. However, in discussing selected aspects of transport in port towns it is necessary to refer to the managing of integrated transport system with taking into account its traffic safety aspects.
Selected studies of flow maldistribution in a minichannel plate heat exchanger
- Paweł Dąbrowski
- Michał Klugmann
- Dariusz Mikielewicz
2017 Full text Archives of Thermodynamics
Analysis of the state of-the-art in research of minichannel heat exchangers, especially on the topic of flow maldistribution in multiple channels, has been accomplished. Studies on minichannel plate heat exchanger with 51 parallel minichannels with four hydraulic diameters, i.e., 461 μm, 574 μm, 667 μm, and 750 μm have been presented. Flow at the instance of filling the microchannel with water at low flow rates has been visualized. The pressure drop characteristics for single minichannel plate have been presented along with the channels blockage, which occurred in several cases. The impact of the mass flow rate and channels’ cross-section dimensions on the flow maldistribution were illustrated.
Selecting Requirements Documentation Techniques for Software Projects: a Survey Study
- Aleksander Jarzębowicz
- Katarzyna Połocka
2017 Full text
A significant number of techniques dedicated to requirements specification and documentation is described in the available sources. As there is no purpose to use all of them, a selection has to be made, taking into consideration the context of a given software project, for example its size, usage of agile approach or stakeholders' technical competency. This paper is intended to provide guidelines for such selection. We reviewed several sources (mainly industrial standards) to identify the general approach to requirements specification and specific techniques they recommend for this purpose. We also proposed a set of attributes describing project's context. Then, we conducted a survey study involving 42 Polish IT industry professionals, asking them to select techniques applicable to different projects. The survey was followed by two interviews with exerienced business analysts to interpret its results. The main contribution of the paper are selection recommendations based on results of survey and interviews.
Selection of optimal location and rated power of capacitor banks in distribution network using genetic algorithm
- Agata Szultka
- Robert Małkowski
2017
In this paper, the problem of placement and rated power of capacitor banks in the Distribution Network (DN) is considered. We try to suggest the best places for installing capacitor banks and define their reactive power. The considered formulation requires the optimization of the cost of two different objectives. Therefore the use of properly multiobjective heuristic optimization methods is desirable. To solve this problem we use a heuristic method such as Genetic Algorithm. The first goal is to achieve a voltage level in every nodes of the power network on required level. The second goal is to limit the cost connected with buying and installing capacitors. Finally, numerical results on a distribution system demonstrate that the proposed formulation and approach are effective and feasible for finding an optimal placement of capacitor banks.
Selective Laser Melting of Ti Alloy for Manufacturing The Prosthetic Elements
- Tomasz Seramak
- Katarzyna Zasińska
- Jerzy Andryskowski
- Mariusz Motyl
- Anna Andryskowska-Ignaczak
- Andrzej Zieliński
2017 International Journal of New Technology and Research
The selective laser melting (SLM) is the additive manufacturing method of custom-designed parts. The used materials and the applications are various, including medicine. The titanium and its alloys are materials for which the dimensional quality, surface smoothness and no or extremely low porosity are difficult to reach. In this paper, the successful attempt to obtain by SLM the individually designed prosthetic bridges is described. The desired elements were obtained by the proper design, the adjustment of laser equipment parameters and necessary surface post-treatment.
Selfie and Personal Branding Phenomena in the Context of the Network Economy. A Literature Review
- Wioleta Kucharska
- Ilenia Confente
2017 Handel Wewnętrzny
Self-taken pictures called “selfies” shared in social media have become a worldwide phenomenon. This is due to the increased need of human being to share to other people their daily lives and to build their own personal brand in the networked world. Despite that, the subject of personal branding has not been sufficiently discussed in academic marketing literature over the past decade. The objective of the study is to present the concept of personal branding and to better understand the role selfie has, being one of the most frequently used social network, in helping people to build personal branding in the online context. Based on a literature review, authors highlight that building a personal brand in the network economy is one of the key factors influencing a personal position in valued networks.