2018 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2018

Pokaż wszystkie

A Reputation Scheme to Discourage Selfish QoS Manipulation in Two-Hop Wireless Relay Networks
- Jerzy Konorski
- Szymon Szott
2018 Pełny tekst
In wireless networks, stations can improve their received quality of service (QoS) by handling packets of source flows with higher priority. Additionally, in cooperative relay networks, the relays can handle transit flows with lower priority. We use game theory to model a two-hop relay network where each of the two involved stations can commit such selfish QoS manipulation. We design and evaluate a reputation-based incentive scheme called RISC2WIN, whereby a trusted third party (e.g., an access point) can limit selfish behavior and preserve appropriate QoS for both stations.
A Review of Standards with Cybersecurity Requirements for Smart Grid
- Rafał Leszczyna
2018 Pełny tekst COMPUTERS & SECURITY
Assuring cybersecurity of the smart grid is indispensable for the reliable operation of this new form of the electricity network. Experts agree that standardised solutions and practices should be applied in the first place. In recent years many new standards for smart grids have been published, which paradoxically results in the difficulty of finding a relevant publication in this plethora of literature. This paper presents results of a study which aimed at addressing this issue by identifying all standards that define cybersecurity requirements applicable to smart grids. Based on a systematic literature review seventeen relevant standards were identified that are described in this paper with a focus on the requirements and characterised with respect to evaluation criteria. The relationships between the standards have been analysed to understand where the standards overlap or complement each other and where they are completely independent -- as far as cybersecurity requirements are concerned. This together with the requirements-focused descriptions of the standards can serve as a useful guidance on cybersecurity requirements for smart grid components that should help practitioners in choosing the standards that are applicable to their area or a specific problem.
A role of an Enterprise Identification Card in a building process of water tourist investments
- Emilia Miszewska
- Adam Bolt
- Magdalena Apollo
2018 Pełny tekst E3S Web of Conferences
An essential element of a building process for water tourist investments in Poland is a document called the Enterprise Identification Card. It is required for the investments, which are classified according to the Regulation [1] as the ones that could potentially impact the environment. It is assumed that KIP is there to protect the environment against the excessive human interference and it just provides the guidelines regarding the enterprise completion for an applicant. TOWS-SWOT analysis has been used in order to conduct an accurate evaluation of a role of the Enterprise Identification Card in a building process of water tourist investments. It is one of the modifications of the basic method of strategic analysis SWOT.
A Set of Low-power Microcontroller-based Modules Used for Testing of Small Energy Measurement Methods
- Dariusz Palmowski
- Grzegorz Lentka
- Jerzy Rutkowski
2018 Pełny tekst Przegląd Elektrotechniczny
Estimation of energy consumption of low-power devices is not widely discussed in the scientific literature, but this topic is getting more and more popular. Evaluation process of newly developed methods and instrumentation requires carefull treatment. In order to fulfill this niche, the set of micro-power microcontroller based devices was proposed. The devices represent typical energy consuption profiles and allow experimental verification of newly developed methods for energy estimation.
A Ship Domain-Based Method of Determining Action Distances for Evasive Manoeuvres in Stand-On Situations
- Rafał Szłapczyński
- Przemysław Krata
- Joanna Szłapczyńska
2018 Pełny tekst JOURNAL OF ADVANCED TRANSPORTATION
A ship encounter can be considered safe if neither of ships’ domains (defined areas around ships) is intruded by other ships. Published research on this includes optimising collision avoidancemanoeuvres fulfilling domain-based safety conditions.However, until recently there was no method, using ship’s domain to determine exact moment when a particular collision avoidance manoeuvre can still be successfully performed. The authors have already proposed such method for give-way encounters. In the paper, documenting continuation of the research, another kind of scenarios is considered.This paper is focused on situations where the own ship is the stand-on one and the target is supposed to manoeuvre. The presented method uses a ship’s dynamics model to compute distance necessary for a manoeuvre successful in terms of avoiding domain violations. Additionally, stability-related phenomena and their impact on possible manoeuvres in heavy weather are taken into account. The method and applied models are illustrated in a series of simulation results.The simulations cover various examples of stand-on situations, including encounters in heavy weather conditions. Discussed manoeuvres may be limited to course alteration or may combine turns with speed reduction.
A simplified energy dissipation based model of heat transfer for post-dryout flow boiling
- Jarosław Mikielewicz
- Dariusz Mikielewicz
2018 Pełny tekst INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
model for post dryout mist flow heat transfer is presented based on considerations of energy dissipation in the flow. The model is an extension of authors own model developed earlier for saturated and subcooled flow boiling. In the former version of the model the heat transfer coefficient for the liquid singlephase convection as a reference was used, due to the lack of the appropriate model for heat transfer coefficient for the mist flow boiling. That issue was a fundamental weakness of the former approach. The purpose of present investigation is to fulfil this drawback. Now the reference heat transfer coefficient for the saturated flow boiling is that corresponding to vapour flow the end of the mist flow. The wall heat flux is based on partitioning and constitutes of two principal components, namely the convective heat flux for vapour flowing close to the wall and two phase flow droplet–vapour in the core flowing. Both terms are accordingly modelled. The results of calculations have been compared with some experimental correlations from literature showing a good consistency.
A Solution to Image Processing with Parallel MPI I/O and Distributed NVRAM Cache
- Artur Malinowski
- Paweł Czarnul
2018 Pełny tekst Scalable Computing: Practice and Experience
The paper presents a new approach to parallel image processing using byte addressable, non-volatile memory (NVRAM). We show that our custom built MPI I/O implementation of selected functions that use a distributed cache that incorporates NVRAMs located in cluster nodes can be used for efficient processing of large images. We demonstrate performance benefits of such a solution compared to a traditional implementation without NVRAM for various sizes of buffers used to read image parts, process and write back to storage. We also show that our implementation benefits from overlapping reading subsequent images while processing already loaded ones. We present results obtained in a cluster environment for three parallel implementation of blur, multipass blur and Sobel filters, for various NVRAM parameters such as latencies and bandwidth values.
A Stabilized Complex LOBPCG Eigensolver for the Analysis of Moderately Lossy EM Structures
- Michał Rewieński
- Adam Dziekoński
- Adam Lamęcki
- Michał Mrozowski
2018 IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
This letter proposes a stabilized locally optimal block preconditioned conjugate gradient method for computing selected eigenvalues for complex symmetric generalized non-Hermitian eigenproblems. Effectiveness of the presented approach is demonstrated for a moderately lossy dual-mode dielectric resonator, modeled using finite-element method with higher order elements
A Stand for Measurement and Prediction of Scattering Properties of Diffusers
- Adam Kurowski
- Damian Koszewski
- Józef Kotus
- Bożena Kostek
2018
In this paper we present a set of solutions which may be used for prototyping and simulation of acoustic scattering devices. A system proposed is capable of measuring sound field. Also a way to use an open source solution for simulation of scattering phenomena occurring in proximity of acoustic diffusers is shown. The result of our work are measurement procedure and a prototype of the simulation script based on FEniCS - an open source computing platform for the FEM-based solution of differential equations. A visualization and comparison between data obtained from measurement and an example of the simulation scenario are presented and discussed.
A study of a reduction of a micro- and nanometric bismuth oxide in hydrogen atmosphere
- Bartosz Jakub Trawiński
- Beata Bochentyn
- Bogusław Kusz
2018 Pełny tekst THERMOCHIMICA ACTA
A reduction of bismuth oxide in hydrogen atmosphere was investigated. The reaction was performed with a material in various structural forms: powder: with micrometric grains, powder with nanometric grains and powder pressed into pellets. The process was performed in both isothermal and non-isothermal conditions. An activation energy of the reaction calculated with Friedman method was found to be about 85 kJ/mol for the reduction of both micrometric powder and pellets. A model fitting analysis based on Coats-Redfern method suggests, that the reaction is limited by a diffusion of gaseous reactants, what is consistent with a structural analysis. An effect of liquid bismuth evaporation was noticed at the beginning of the process. This phenomenon was much stronger in the case of reduction of nanometric powder. The activation energy was estimated to be about 30 – 50 kJ/mol. The reaction could have been performed at lower temperature.
A Study on Audio Signal Processed by "Instant Mastering"
- Magdalena Piotrowska
- Szymon Piotrowski
- Bożena Kostek
2018
An increasing amount of music produced in home- and project-studios results in development and growth of "automatic mastering services". The presented investigation explores changes introduced to audio signal by various online mastering platforms. A music set consisting of 10 songs produced in small facilities was processed by eight on-line automatic mastering services. Additionally, some laboratory-constructed signals were tested. To determine, whether changes introduced to audio are invariable between trials, every music excerpt was submitted several times. For each sample, parameters related to music characteristics such as timbre, dynamics and loudness were calculated before and after processing. Results obtained enable to discover some of the mechanisms underlying tested automatic mastering services as well as discern similarities and differences between various platforms.
A study on of music features derived from audio recordings examples – a quantitative analysis
- Aleksandra Dorochowicz
- Bożena Kostek
2018 Pełny tekst Archives of Acoustics
The paper presents a comparative study of music features derived from audio recordings, i.e. the same music pieces but representing different music genres, excerpts performed by different musicians, and songs performed by a musician, whose style evolved over time. Firstly, the origin and the background of the division of music genres were shortly presented. Then, several objective parameters of an audio signal were recalled that have an easy interpretation in the context of perceptual relevance. Within the study parameter values were extracted from music excerpts, gathered and compared to determine to what extent they are similar within the songs of the same performer or samples representing the same piece.
A study on transverse shear correction for laminated sandwich panels
- Ireneusz Kreja
- Agnieszka Sabik
2018
The paper presents a study on an application of the First Order Shear Deformation Theory in a linear static analysis of elastic sandwich panels. A special attention has been given to the issue of the transverse shear correction. Two benchmark examples of sandwich plate problems with known reference solutions have been selected for a comparative analysis performed with own Finite Element codes. Interesting results allowed for drawing some conclusions.
A Survey Investigating the Influence of Business Analysis Techniques on Software Quality Characteristics
- Katarzyna Mossakowska
- Aleksander Jarzębowicz
2018 Pełny tekst
Business analysis is recognized as one of the most important areas determining the outcome (success or failure) of a software project. In this paper we explore this subject further by investigating the potential impact of techniques applied in business analysis on essential software quality characteristics. We conducted a literature search for software quality models, analyzed the existing models and selected a subset of commonly recognized quality characteristics. Also, we identified a representative set of recommended state-of-the-art business analysis techniques. These two sets provided the basis for questionnaire survey and interviews. We conducted a survey involving 20 industry professionals, followed up by 2 interviews with experienced business analysts to discuss and interpret survey re-sults. The main outcome are recommendations regarding techniques to be used in software project for a given quality characteristic considered essential.
A three-dimensional meso-scale approach to concrete fracture based on combined DEM with x-ray micro-CT images
- Michał Nitka
- Andrzej Tejchman-Konarzewski
2018 CEMENT AND CONCRETE RESEARCH
Artykuł omawia wyniki numeryczne uzyskane stosując 3-wymiarowy mezoskopowy model do opisu pękania w betonie na poziomie kruszywa w belce z nacięciem podczas zginania. Do obliczeń użyto metodę elementów dyskretnych. Beton został opisany jako materiał 4-fazowy złożony z kruszywa, zaprawy, makro-porów i stref przejściowych miedzy kruszywem a zaprawą. Kształt i położenia kruszywa przyjęto na podstawie skanów z mikro-tomografu. Uzyskano dobrą zgodność wyników numerycznych z doświadczalnymi. Wyniki 3D porównano z wynikami 2D.
A three-dimensional meso-scale approach with cohesive elements to concrete fracture based on X-ray μCT images.
- Wojciech Trawiński
- Andrzej Tejchman-Konarzewski
- Jerzy Bobiński
2018 ENGINEERING FRACTURE MECHANICS
Artykuł omawia wyniki numeryczne dotyczące pękania betonu uzyskane stosując trójwymiarowy model mezoskopowy z elementami kohezyjnymi. Obliczenia trójwymiarowe zostały wykonane dla zginanej belki betonowej. Beton został opisany jako model 3-fazowy. Mikrostruktura betonu odpowiadała zdjęciom tomograficznym. Wyniki numeryczne zostały porównane z wynikami doświadczalnymi. Uzyskano b. dobra zgodność między wynikami numerycznymi i doświadczalnymi.
A universal NDT method for examination of low energy impact damage in CFRP with the use of TLC film
- Gabriel Strugała
- Michał Klugmann
- Michał Landowski
- Marek Szkodo
- Dariusz Mikielewicz
2018 Nondestructive Testing and Evaluation
The article presents an attempt to use a sheet of laminated thermochromic liquid crystal film (TLC film) for non-destructive testing of the impact damage (energy values: 1J, 2J, 3J and 4J) in carbon fibre-reinforced polymer (CFRP). This is a new, alternative NDT approach based on the thermo-optical effect. The main advantages of this method are a) the low cost of TLC film, b) the low cost of recording devices due to the usage of conventional digital recording equipment and c) the low requirements for tests. The TLC film method was compared with two other conventional NDT methods: computer radiography (CR) and active thermography (thermographic camera). The scatter of results regarding the average crack length (TLC film and active thermography) was ±5% in relation to the CR method. The damage area (impact energy 2J to 4J) showed a similar shape (TLC film vs active thermography) and the scatter of results for the TLC film was ±2% in relation to the active thermography method. Only the CR detected the damage caused by 1J impact energy. The comparative studies have proven that the described method (TLC film) is a fullfledged and accurate tool for NDT method for the diagnosis of impact damage in CFRP.
Ab-initio study of electrical and optical properties of allylamine
- Bartłomiej Dec
- Krzysztof Pyrchla
- Robert Bogdanowicz
2018 Pełny tekst Photonics Letters of Poland
The Density functional theory is one of most promising methodology in fast and accurate calculations of electrical and optical properties from the atomic basis. In this paper, we calculate electrical and optical properties of allylamine (2-propen 1- amine) in terms of accuracy and speed of calculations obtained by selection of DFT-1/2 method with ultrasoft Vanderbilt pseudopotentials. Comparison of density of states between molecule and bulk configuration shows great agreement between them, therefore we calculated refractive index which showed even better agreement with experimental data.
Acceleration waves in the nonlinear micromorphic continuum
- Victor Eremeev
- Leonid Lebedev
- Michael Cloud
2018 Pełny tekst MECHANICS RESEARCH COMMUNICATIONS
Within the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for the micromorphic medium and formulate the conditions for existence of acceleration waves. As examples we consider these conditions for the linear micromorphic medium and for the relaxed micromorphic model.
Accuracy analysis of 3D model obtained by photogrammetric method on the example of historic room from Wisłoujście Fortress
- Tadeusz Widerski
- Karol Daliga
2018 Pełny tekst E3S Web of Conferences
The article presents a comparison of obtained models of a test object. Close range photogrammetry was used to obtain 3D models. As test object was used one of the rooms located in Wisłoujście Fortress in Gdańsk, Poland. Different models were obtained by using different distribution and number of reference points. Article contains analysis of differences between coordinates of control points obtained from total station measurements and estimated from different 3D models.