2014 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2014

Pokaż wszystkie

Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations
- Małgorzata Śmiałek-Telega
- Marta Łabuda
- Julien Guthmuller
- Marie-Jeanne Hubin-Franskin
- Jacques Delwiche
- Denis Duflot
- N.j. Mason
- Soren Vrønning-Hoffmann
- N. C. Jones
- P. Limao-Vieira
2014 Pełny tekst JOURNAL OF CHEMICAL PHYSICS
The highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO, yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of ethyl formate and are compared with a newly recorded He(I) photoelectron spectrum (from 10.1 to 16.1 eV). New vibrational structure is observed in the first photoelectron band. The photoabsorption cross sections have been used to calculate the photolysis lifetime of ethyl formate in the upper stratosphere (20–50 km).
Variable Fractional Delay Filter Design Using a Symmetric Window
- Marek Blok
- Maciej Sac
2014 Pełny tekst CIRCUITS SYSTEMS AND SIGNAL PROCESSING
In this paper a numerically efficient method for designing a nearly optimal variable fractional delay (VFD) filter based on a simple and well-known window method is presented. In the proposed method a single window extracted from the optimal filter with fixed fractional delay (FD) is divided into even and odd part. Subsequently, the odd part is discarded and symmetric even part of the extracted window is used to design a family of nearly optimal filters with varying FD. In addition to window extraction, the proposed approach requires filter gain correction which is dependent on the desired FD. Optimum values of the gain correction factor as well as the extracted window can be computed beforehand, which allows us to design a nearly optimal FD filter with arbitrary FD at low numerical costs during runtime. On the basis of the proposed filter design method, the universal structure of VFD filter allowing for change of filter type and length has been proposed. In the paper, three FD filter optimality criteria are considered, which are maximal flatness, Chebyshev (minimax), and least squares.
Variable Ratio Sample Rate Conversion Based on Fractional Delay Filter
- Marek Blok
- Piotr Drózda
2014 Pełny tekst Archives of Acoustics
In this paper a sample rate conversion algorithm which allows for continuously changing resampling ratio has been presented. The proposed implementation is based on a variable fractional delay filter which is implemented by means of a Farrow structure. Coefficients of this structure are computed on the basis of fractional delay filters which are designed using the offset window method. The proposed approach allows us to freely change the instantaneous resampling ratio during processing. Using such an algorithm we can simulate recording of audio on magnetic tape with nonuniform velocity as well as remove such distortions. We have demonstrated capabilities of the proposed approach based on the example of speech signal processing with a resampling ratio which was computed on the basis of estimated fundamental frequency of voiced speech segments.
Velocity Field Characteristics at the Inlet to a Pipe Culvert
- Tomasz Kolerski
- Paweł Wielgat
2014 Pełny tekst Archives of Hydro-Engineering and Environmental Mechanics
A poorly designed culvert inlet structure causes scouring, which can lead to the collapse of the culvert and significant damage to the neighboring land. A set of laboratory tests was evaluated to examine velocity distribution at the culvert inlet. A three-dimensional acoustic Doppler velocimeterwas used to measure instantaneous flowvelocity upstream of the culvert. The analysis of mean velocities, turbulence strength, and Reynolds stresses was performed to understand the flow structure near the culvert entrance.
Velocity measurement using the fdoa method in ground-based radio navigation system
- Jarosław Sadowski
2014 Pełny tekst Metrology and Measurement Systems
Velocity is one of the main navigation parameters of the moving objects. However some systems of position estimation using radio wave measurements cannot provide velocity data due to limitation of their performance. In this paper a velocity measurement method for DS-CDMA radio navigation system is proposed, which doesn’t require full synchronization of reference stations carrier frequencies. The article presents basics of FDOA (frequency difference of arrival) velocity measurements together with application of this method to experimental radio navigation system called AEGIR and with some suggestions about the possibility to implement such FDOA measurements in other kinds of asynchronous DS-CDMA radio networks. Main part of this paper present results of performance evaluation of proposed method, based on laboratory measurements.
Verification of algorithms determining wave loads on support structure of wind turbine
- Andrzej Jankowski
- Paweł Dymarski
2014
The offshore wind turbines require determination of wave loads on their support structure. This structure is fixed and, therefore, this problem is reduced to solving only the diffraction problem, which is determined by Laplace equation and conditions on the following boundaries: on the support structure, on the sea free surface and on its bottom, and at infinity on free surface. The linear problem was applied to determine the wave loads. The assumption of the solution of the problem has a form of single potential layer which converts the differential problem into Fredholm equation of second kind. This ap- proach is based on the Green function satisfying the condition on the sea free surface and on its bottom (finite depths), there- fore, it is enough to fulfill the boundary condition on a support structure. In numerical solution, the discretization of the tower surface into boundary elements (panels) is only required. The algorithm developed, based on the Boundary Element Method, requires verification. In this purpose as a form of wind support structure the cylinder was used, for which exact solution of the diffraction problem exist. In the verification, wave pressures distributed on the cylinder surface and generated forces and moments, obtained in numerical solution of the problem have been compared with the exact theoretical results. The numeri- cal and theoretical results were well compared, and was concluded that the algorithm developed can be applied to the wind support structure of more complicated forms. In this paper the following is presented: the differential problem and Fredholm equation determining the diffraction problem, tables and graphs showing the comparison of the theoretical and numerical results, conclusions for further work.
Vertical vibration reduction and audible sound analysis in surface grinding with electroplated tools
- Mariusz Deja
2014 Pełny tekst Journal of Measurements in Engineering
One of the first approaches to the development of a grinding process monitoring system based on audible sound sensors is presented in the paper. Electroplated diamond tools (abrasive D64 and D107) were used in a modified single-disc lapping machine configuration for flat grinding of ceramics (Al2O3). The main aim of the machine modification was to reduce the vertical vibration in order to decrease the tool wear and to increase the material removal rate. The sound generated by the material processing was analysed in the aspect of actual abrasive ability of the grinding tools. The abrasive properties of the tool are decreasing during machining due to the wear of diamond grains. The results from experiments, such as the material removal rates and waveforms of recorded sound are presented and discussed in the paper.
Viability of decisional DNA in robotics
- Carl Sheffer
- Edward Szczerbicki
- Cesar Sanin
2014 Pełny tekst Procedia Computer Science
The Decisional DNA is an artificial intelligence system that uses prior experiences to shape future decisions. Decisional DNA is written in the Set Of Experience Knowledge Structure (SOEKS) and is capable of capturing and reusing a broad range of data. Decisional DNA has been implemented in several fields including Alzheimer’s diagnosis, geothermal energy and smart TV. Decisional DNA is well suited to use in robotics due to the large amount of data available and the generally repetitive nature of the tasks robots perform. However, there is very little evidence about the system’s performance in this application. This project aims to assess the viability of SOEKS in robotics. Several knowledge representation approaches were explored then coded in the Java programming language. A hardware platform was constructed from readily available electronics and set up to be compatible with the Java language. Codes were installed on the hardware platform and tested by conducting a series of feature mapping tasks. Success of this project could lead to the future use of SOEKS in robot control.
VIBRATION DIAGNOSTICS OF FOOTBRIDGE WITH USE OF ROTATION SENSOR
- Anna Banaś
- Krzysztof Wilde
2014 Pełny tekst APPLIED COMPUTER SCIENCE
The benefits of the additional measurement of rotational degrees of free-dom on the performance of the vibration diagnosis of bridges are studied in this paper. The common vibrational diagnostics that uses translational degrees of freedom is extended by measurements of rotations. The study is curried out on a footbridge and the presence of damage as well as its location and size is determined with use of FEM updating procedure. The results showed that rotational degrees of freedom significantly improve the effectiveness of the vibrational method.
Vibration surveillance for efficient milling of flexible details fixed in adjustable stiffness holder
- Krzysztof Jan Kaliński
- Marek Chodnicki
- Marek Galewski
- Michał Mazur
2014 Vibroengineering Procedia
The paper presents the results of research related to the possibility of using an intelligent workpiece holder with adjustable stiffness, during end milling process. Machining a one side supported flexible workpiece will be performed with constant spindle speed and feed speed. In order to avoid hazardous vibration, stiffness of the especially designed spring (mounted in a workpiece holder) will be modified off-line. In order to predict the accuracy of the proposed method, appropriate simulations were performed. As a simplified model of the flat workpiece it was applied the Euler-Bernoulli bar with possibility of identifying the two lowest normal modes. On this basis and for approaching optimal spindle speeds, the mean of adjusting relevant stiffness of the holder is invented.
Vibration surveillance supported by Hardware-In-the-Loop Simulation in milling flexible workpieces
- Krzysztof Jan Kaliński
- Marek Galewski
2014 MECHATRONICS
W artykule przedstawiono nowoczesne podejście do problemu minimalizacji poziomu drgań podczas frezowania szybkościowego elementów podatnych. Do analizy dynamicznej procesu skrawania zastosowano niestacjonarny model opisany we współrzędnych hybrydowych. Na tej podstawie, przy wykorzystaniu energetycznego wskaźnika jakości wyprowadzono opis sygnału sterującego. Sygnał ten jest następnie stosowany do aktywnej redukcji drgań przedmiotu podczas frezowania. Jako element wykonawczy zastosowano wzbudniki piezoelektryczny. W celu predykcji rezultatów nadzorowania i doboru parametrów sterowania wykorzystano technikę symulacji Hardware-in-the-Loop. Ostateczne rezultaty zweryfikowano podczas badań eksperymentalnych.
Vibration Surveillance System with Variable Stiffness Holder for Milling Flexible Details
- Krzysztof Jan Kaliński
- Marek Chodnicki
- Michał Mazur
- Marek Galewski
2014
Efficient milling of the flexible details (i.e. rotor blades, thin-walled elements) using slender ball-end tools is a difficult task due to possibility of vibration occurrence. Because of the existence of certain conditions (small depths of cutting, regeneration phenomena), cutting process may lose stability and self-excited chatter vibration may appear. Frequency of the chatter vibration is close to dominant natural frequency of the workpiece or the tool. One of the methods of chatter vibration avoidance is matching the spindle speed to the optimal phase shift between subsequent cutting edge passes (i.e. the Liao–Young condition). In previous works the authors successfully implemented the idea of optimal speeds map where optimal speed was calculated for every point of the machined surface based on the dominant natural frequencies for local areas. During milling, spindle speed was set according to the map. However, changing spindle speed during tool pass may reduce surface quality in speed change point and is difficult to perform it in some milling centres. The article presents the idea of a new workpiece holder with adjustable stiffness. Milling process will be performed with constant spindle and feed speed. In order to avoid vibration, stiffness of the specially designed workpiece holder will be modified off-line. Stiffness changes modify natural frequencies of the workpiece and thus, it is possible to modify dynamic properties of the workpiece in such a way that arbitrary chosen, constant spindle speed will be optimal, due to the Liao–Young condition performance. This will need calculation of the optimal stiffness map (referred to different spindle speeds), which will be performed before milling based on the workpiece’s modal identification results and Finite Element Model simulations.
Virtual Engineering Objects (VEO): Designing, Developing and Testing Models
- Syed Imran Shafiq
- Cesar Sanin
- Edward Szczerbicki
- Carlos Toro
2014
In this article, the development and implementation of the concept of Virtual Engineering Object (VEO) is described. A VEO is a computerized real world representation of an engineering object. VEO will act as a living representation of the object capable of adding, storing, improving and sharing knowledge through experience, in a way similar to an expert of that object. In this paper, it is shown through test models how the concept of VEO can be implemented with the Set of Experience Knowledge Structure (SOEKS) and Decisional DNA. The SOEKS/DDNA is a flexible and standard knowledge representation structure to acquire and store experiential knowledge. A test case study for three different drilling machines, drilling tools and the working holding devices is developed to test and demonstrate the implementation of VEO. The test model confirmed that the concept of VEO is able to capture and reuse the experience of the engineering artifacts, which can be beneficial for efficient decision making in industrial design and manufacturing.
Visible light photoactivity of TiO2loaded with monometallic(Au or Pt) and bimetallic (Au/Pt) nanoparticles
- Anna Gołąbiewska
- Wojciech Lisowski
- Marcin Jarek
- Grzegorz Nowaczyk
- Anna Zielińska-Jurek
- Adriana Zaleska-Medynska
2014 APPLIED SURFACE SCIENCE
TiO2modified with monometallic (Au or Pt) and bimetallic (Au/Pt) nanoparticles have been preparedusing a water-in-oil microemulsion system (water/AOT/cyclohexane) followed by calcination step. Theeffect of metal ratio, reducing agent type (NaBH4or N2H4), TiO2matrix type (P-25, ST-01, TiO-5, TiO2nano-tubes or TiO2obtained by TIP hydrolysis) as well as calcination temperature (from 350 to 650◦C) weresystematically investigated. Obtained photocatalysts were characterized by UV–vis diffuse-reflectancespectroscopy (DRS), BET surface area measurements, scanning transmission microscopy (STEM), X-raydiffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity undervisible light ( > 420 nm) has been estimated in phenol degradation reaction in aqueous phase. Theresults showed that phenol degradation rate under visible light in the presence of TiO2loaded with Au/Ptnanoparticles differed from 0.7 to 2.2 mol dm−3min−1for samples prepared using different reducingagent. Sodium borohydride (NaBH4) favors formation of smaller Au/Pt nanoparticles and higher amountgold in Au/Pt is in the form of electronegative species (Auı−) resulted in higher photoactivity. TiO2obtained by TIP hydrolysis in microemulsion system seems to be the best support for Au/Pt nanoparticlesfrom all among investigated matrix. It was also observed that enhancement of calcination temperaturefrom 450 to 650◦C resulted in rapid drop of Au/Pt-TiO2photoactivity under visible light due to surfacearea shrinkage, crystal structure change and probably change in Au/Pt nanoparticles morphology.
Visual Features for Endoscopic Bleeding Detection
- Adam Brzeski
2014 Pełny tekst Current Journal of Applied Science and Technology (British Journal of Applied Science & Technology)
Aims: To define a set of high-level visual features of endoscopic bleeding and evaluate their capabilities for potential use in automatic bleeding detection. Study Design: Experimental study. Place and Duration of Study: Department of Computer Architecture, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, between March 2014 and May 2014. Methodology: The features have been established and evaluated on images extracted from 135 different endoscopic examinations. A set of measures were proposed in order to evaluate the quality of the features. The potential contribution of the features for bleeding detection is evaluated by utilizing an SVM classifier on the vectors constructed by manually assigning the features values to the endoscopic images. Potential limitations of the features' implementations are simulated by introducing noise to the assigned values. Finally, the recognition efficiency of the method is compared to implementations of two bleeding detection algorithms from the literature. Results: The experiments show a potential of bleeding detection efficiency of 95%, assuming perfect features' implementations, and 90% when features' evaluation efficiency of 95% is assumed. Conclusion: By introducing the visual features, the challenging problem of detecting bleeding in endoscopic images is split into a set of smaller image processing problems. The divide-and-conquer approach based on the proposed visual features is capable of achieving high detection efficiency; at the same time providing additional benefits of a more apparent processing scheme, and a possibility of justifying the decisions in a human-readable form.
Visual Lip Contour Detection for the Purpose of Speech Recognition
- Piotr Dalka
- Piotr Bratoszewski
- Andrzej Czyżewski
2014
A method for visual detection of lip contours in frontal recordings of speakers is described and evaluated. The purpose of the method is to facilitate speech recognition with visual features extracted from a mouth region. Different Active Appearance Models are employed for finding lips in video frames and for lip shape and texture statistical description. Search initialization procedure is proposed and error measure values are monitored in order to prevent the matching process from converging to a false local minimum. AAM-based visual features are applied in an experiment devoted to the static recognition of English vowels with SVM. Studies are carried out based on a database of recordings of 5 speakers of different skin colors. Results are thoroughly discussed and illustrated with figures.
Visualization of Spatial Issues in Adobe Acrobat 3D PDF
- Bożena Kotarska-Lewandowska
2014 Pełny tekst The Journal of Polish Society for Geometry and Engineering Graphics
The ability to capture and embed model information in a 3D PDF file and subsequently share it for free is highly needed in the education of descriptive geometry. The described technology and in particular inserting 3D models into the other files can improve the existing teaching materials. The strongest point of 3D PDF technology is that the model can be visualized and manipulated in multiple ways by viewers which enhance the spatial vision.
Volunteer Computing System Comcute with Smart Scheduler
- Jerzy Balicki
- Tomasz Bieliński
- Waldemar Korłub
- Jacek Paluszak
2014
In this paper, a volunteer grid called Comcute is studied. Moreover, the harmony search scheduler is proposed. This scheduler has been designed for efficient using some resources of volunteer grid. The harmony search scheduler optimizes both a workload of a bottleneck computer and the cost of grid. Finally, some experiment outcomes have been discussed.
W poszukiwaniu zielonej techniki ekstrakcyjnej
- Jacek Namieśnik
- Agnieszka Bielińska
2014 Analityka: Nauka i Praktyka
Konieczność wprowadzania do praktyki analitycznej zasad zielonej chemii, ktore bezpośrednio wynikają z koncepcji zrównoważonego rozwoju, sprawia, że trwają poszukiwania nowych rozwiązań metodycznych i aparaturowych.
W stronę menedżeryzmu sądowego - czy zasady Petera F. Druckera można wykorzystać w budowaniu nowoczesnego wymiaru sprawiedliwości w Polsce
- Przemysław Banasik
2014
W rozdziale dokonano diagnozy problemów występujących w obrębie zarządzania wymiarem sprawiedliwości. Przeprowadzono również syntetyczną analizę kierunków przeprowadzenia koniecznych zmian aby wymiar ten stał się nowoczesny i odpowiadał aktualnym trendom i potrzebom stawianym przed administracją publiczną.