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Influence of water salinity on corrosion risk - the case of the southern Baltic Sea coast.
PublicationWater corrosivity in Gdansk Bay, Poland, the southern part of the Baltic Sea, was investigated. The analysed region is heavily industrialized, and the coastline is very diverse. Twenty-seven test points along the coastline were selected. Water parameters such as salinity, total dissolved solids content, resistivity, conductivity, oxygenation, pH and corrosion rate were determined. The results of the investigation are presented....
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Evolution of the HVDC Link Connecting Offshore Wind Farms to Onshore Power Systems
PublicationThis paper presents an overview of the DC link development and evolution dedicated to HVDC structure for connecting offshore wind power plants to onshore power systems. The growing demand for the green energy has forced investors in power industry to look for resources further out at sea. Hence, the development of power electronics and industrial engineering has enabled offshore wind farms to be situated further from the shore...
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Geospatial Coverage and Signal Quality Measurements of Terrestrial DAB+ Network in Northern Poland
PublicationModern signal coverage maps are prepared based on industry-standard radio propagation models, which take into account a number of parameters, including: type of antenna, distance from the transmitter, type of terrain, etc. However, such simulations are prone to location-specific inaccuracies, and should be verified with in-situ measurements. This paper presents results of a field test of a terrestrial DAB+ (Digital Audio Broadcasting...
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Structural optimization of microjet array cooling system
PublicationThe single phase heat transfer from an upward facing, horizontal copper surface to arrays of impinging water jets was experimentally investigated. Experimental configuration allows for a free-surface unconfined jets flow. Square nozzles 50 × 100 μm arranged in four different geometries were used. Additionally, for the set of two jets array geometry was varied by adjusting the nozzle to nozzle distance. The area averaged heat transfer...
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Propagation Loss and Interference Analysis for 5G Systems in the Context of C-ITS System Implementation
PublicationThe article presents the concept of implementing subsequent phases of services for the C-ITS system (the Cooperative Intelligent Transport Systems), based on the European Parliament resolution of March 2018. Next, the 5G systems, in the context of their possible cooperation with C-ITS systems, were discussed. Numerical propagation analysis was performed for V2V and V2I type communication based on two different propagation models....
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Structure of solvation water around the active and inactive regions of a type III antifreeze protein and its mutants of lowered activity
PublicationWater molecules from the solvation shell of the ice-binding surface are considered important for the antifreeze proteins to perform their function properly. Herein, we discuss the problem whether the extent of changes of the mean properties of solvation water can be connected with the antifreeze activity of the protein. To this aim, the structure of solvation water of a type III antifreeze protein from Macrozoarces americanus (eel...
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Assessing unsignalised pedestrian crossings
PublicationThe lack of pedestrian safety on crossings is a complex problem and one that is influenced by a number of factors such as the law, road traffic culture, the road and traffic. This paper will focus on the last two by presenting a method for assessing pedestrian crossings for their geometry and roadside using data from 930 pedestrian crossings in Warsaw. The authors of this paper have attempted to systematise the process of assessment...
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Looking through the past: better knowledge retention for generative replay in continual learning
PublicationIn this work, we improve the generative replay in a continual learning setting to perform well on challenging scenarios. Because of the growing complexity of continual learning tasks, it is becoming more popular, to apply the generative replay technique in the feature space instead of image space. Nevertheless, such an approach does not come without limitations. In particular, we notice the degradation of the continually trained...
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Local-Global Space Mapping for Rapid EM-Driven Design of Compact RF Structures
PublicationIn this work, we introduce a robust and efficient technique for rapid design of compact RF circuits. Our approach exploits two-level space mapping (SM) correction of an equivalent circuit model of the structure under design. The first SM layer (local correction) is utilized to ensure good matching between the equivalent circuit and the electromagnetic model at the component level. On the other hand, the global correction allows...
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Zero-pole approach to computer aided design of in-line siw filters with transmission zeros
PublicationThis paper presents a design of a new type of in-line pseudo-elliptic filters implemented in substrate integrated waveguide(SIW) technology. To realize transmission zeros in in-line topology,frequency-dependent couplings were used. Such dispersive couplingswere implemented as shorted stubs. The design process startswith the generation of a suitable starting point. To this end, anapproximation of SIW as a rectangular waveguide is...
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Network-aware Data Prefetching Optimization of Computations in a Heterogeneous HPC Framework
PublicationRapid development of diverse computer architectures and hardware accelerators caused that designing parallel systems faces new problems resulting from their heterogeneity. Our implementation of a parallel system called KernelHive allows to efficiently run applications in a heterogeneous environment consisting of multiple collections of nodes with different types of computing devices. The execution engine of the system is open for...
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An Off-Body Narrowband and Ultra-Wide Band Channel Model for Body Area Networks in a Ferry Environment
PublicationIn the article an off-body narrowband and ultra-wide band channel model for Body Area Networks in a ferry environment is described. A mobile, heterogeneous measurement stand, that consists of three types of devices: miniaturized mobile nodes, stationary reference nodes and a data acquisition server was developed. A detailed analysis of both radio channels parameters in untypical indoor environment was carried out. An analysis of...
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The Impact of Hybrid Flame Retardant Compositions on the Performance of Foamed Flexible Polyurethane/Ground Tire Rubber Composites
PublicationCurrent sustainability-oriented trends affect polyurethane (PU) materials and stimulate the incorporation of recycled or waste-based materials as fillers. Ground tire rubber (GTR) poses as an auspicious candidate due to the excellent performance of car tires. Despite the benefits related to the mechanical performance, it contributes to the increasing flammability of the resulting composites. Herein, presented work assessed the...
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Encouraging pro-environmental behaviour through an educational mobile application: Preliminary insights from early adopters
PublicationThis article aims to explore the extent to which the educational mobile application PULA supports and promotes pro-environmental behaviours, identify the most utilised functionalities by early adopters, and explore the least engaged functionalities. The study employs a quantitative approach based on data collected from the application. The analysis provides a comprehensive understanding of users' experiences and behaviours within...
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Encouraging Pro-environmental Behaviour Through an Educational Mobile Application: Preliminary Insights from Early Adopters
PublicationThis article aims to explore the extent to which the educational mobile application PULA supports and promotes pro-environmental behaviours, identify the most utilised functionalities by early adopters, and explore the least engaged functionalities. The study employs a quantitative approach based on data collected from the application. The analysis provides a comprehensive understanding of users' experiences and behaviours within...
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Visual Features for Endoscopic Bleeding Detection
PublicationAims: 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...
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Superconducting SrSnP with Strong Sn–P Antibonding Interaction: Is the Sn Atom Single or Mixed Valent?
PublicationThe large single crystals of SrSnP were prepared using Sn self-flux method. The superconductivity in the tetragonal SrSnP is observed with the critical temperature of ∼2.3 K. The results of a crystallographic analysis, superconducting characterization, and theoretical assessment of tetragonal SrSnP are presented. The SrSnP crystallizes in the CaGaN structure type with space group P4/nmm (S.G. 129, Pearson symbol tP6) according...
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Investigation into MPI All-Reduce Performance in a Distributed Cluster with Consideration of Imbalanced Process Arrival Patterns
PublicationThe paper presents an evaluation of all-reduce collective MPI algorithms for an environment based on a geographically-distributed compute cluster. The testbed was split into two sites: CI TASK in Gdansk University of Technology and ICM in University of Warsaw, located about 300 km from each other, both connected by a fast optical fiber Ethernet-based 100 Gbps network (900 km part of the PIONIER backbone). Each site hosted a set...
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A Highly Sensitive Planar Microwave Sensor for Detecting Direction and Angle of Rotation
PublicationThis article presents a technique based on a modified complementary split-ring resonator (CSRR) to detect angular displacement and direction of rotation with high resolution and sensitivity over a wide dynamic range. The proposed microwave planar sensor takes advantage of the asymmetry of the sensor geometry and measures the angle of rotation in terms of the change in the relative phase of the reflection coefficients. The sensor...
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Low-Cost Automated Design of Compact Branch-Line Couplers
PublicationBranch-line couplers (BLCs) are important components of wireless communication systems. Conventional BLCs are often characterized by large footprints which make miniaturization an important prerequisite for their application in modern devices. State-of-the-art approaches to design of compact BLCs are largely based on the use of high-permittivity substrates and multi-layer topologies. Alternative methods involve replacement of transmission-line...
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Sample preparation procedure using extraction and derivatization of carboxylic acids from aqueous samples by means of deep eutectic solvents for gas chromatographic-mass spectrometric analysis
PublicationThe paper presents a new procedure for the determination of organic acids in a complex aqueous matrixusing ultrasound-assisted dispersive liquid–liquid microextraction followed by injection port derivati-zation and GC–MS analysis. A deep eutectic solvent (choline chloride: 4-methylphenol in a 1:2 mol ratio)was used both as an extracting solvent and as a derivatizing agent to yield ion pairs which were next con-verted to methyl...
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Inverse Modeling and Optimization of CSRR-based Microwave Sensors for Industrial Applications
PublicationDesign optimization of multivariable resonators is a challenging topic in the area of microwave sensors for industrial applications. This paper proposes a novel methodology for rapid re-design and parameter tuning of complementary split-ring resonators (CSRRs). Our approach involves inverse surrogate models established using pre-optimized resonator data as well as analytical correction techniques to enable rapid adjustment of geometry...
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TeleCAD w kształceniu studentów Wydziału Inżynierii Lądowej Politechniki Gdańskiej
PublicationPrzedstawiono system TeleCAD opracowany w ramach projektu Leonardo da Vinci - Teleworkers Training for CAD Systems Users (1998-2001). Głównym celem projektu było stworzenie środowiska obsługi kursów programu AutoCAD bazującego na Internecie jako medium do komunikacji między uczestnikami oraz do dostarczania materiałów kursowych. W artykule zaprezentowano również system służący do oceny jakości szkoleń na odległość. Szkolenie TeleCAD...
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Development and Research of the Text Messages Semantic Clustering Methodology
PublicationThe methodology of semantic clustering analysis of customer’s text-opinions collection is developed. The author's version of the mathematical models of formalization and practical realization of short textual messages semantic clustering procedure is proposed, based on the customer’s text-opinions collection Latent Semantic Analysis knowledge extracting method. An algorithm for semantic clustering of the text-opinions is developed,...
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Autonomous Control of the Underwater Remotely Operated Vehicle in Collision Situation with Stationary Obstacle
PublicationThe article considers the problem of autonomous control of the underwater remotely operated vehicle mini Remotely Operated Vehicle (ROV) in a collision situation with a stationary obstacle. The control of the collision avoidance process is presented as a synthesis of fuzzy proportional-differential controllers for the control of distance and orientation concerning the detected stationary obstacle. The control of the submergence...
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Recent Advances in Graphene Oxide-Based Membranes for Heavy Metal Ions Separation
PublicationGraphene oxide (GO)-based membranes have been widely investigated for separation of dyes, salt ions, heavy metal ions, and biomolecules due to their high mechanical strength, single-layered structure, large surface area, and high affinity. However, due to irregular pore structure, nanochannels, interlayer distance, easy functionalization, swelling effect, and chemical stability under aqueous environment limited their separation...
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The hydrodynamic pressure field of the ship Zodiak, measurements and calculations
PublicationThe article presents the results of measurements of the slowly changing hydrodynamic pressure field HPF generated by the movement of the ship, Zodiak, in the Bay of Gdansk. The measurement results have been obtained in the framework of the program of the work in Siramis, under the auspices of the European Defence Administration of the EU, by the research team of the Naval Academy in Gdynia. The measurement results were compared with...
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Priority-enabled optimization of resource utilization in fault-tolerant optical transport networks.
PublicationW artykule zaproponowano nowe podejście do optymalizacji rozdziału zasobów przeżywalnych sieci rozległych, które uzależnia szybkość przywracania ciągłości połączenia od klasy usługi. Wykazano, iż proponowana metoda nie powoduje wydłużania ścieżek zabezpieczających (w przypadku usług w wymaganej wysokiej jakości obsługi) lub czyni to w sposób minimalny (dla pozostały usług). Ze względu na fakt, że zadanie znalezienia ścieżek aktywnych...
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Facial emotion recognition using depth data
PublicationIn this paper an original approach is presented for facial expression and emotion recognition based only on depth channel from Microsoft Kinect sensor. The emotional user model contains nine emotions including the neutral one. The proposed recognition algorithm uses local movements detection within the face area in order to recognize actual facial expression. This approach has been validated on Facial Expressions and Emotions Database...
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Investigations of Aerodynamics of Tesla Bladeless Microturbines
PublicationThe paper presents an analysis of a Tesla bladeless turbine for a co-generating micro-power plant of heat capacity 20 kW, whichoperates in an organic Rankine cycle with a low-boiling medium. Numerical calculations of flow in several Tesla turbine models areperformed for a range of design parameters. Results of investigations exhibit interesting features in the distribution of flowparameters within the turbine interdisk space. The...
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On the partition dimension of trees
PublicationGiven an ordered partition Π={P1,P2,…,Pt} of the vertex set V of a connected graph G=(V,E), the partition representation of a vertex v∈V with respect to the partition Π is the vector r(v|Π)=(d(v,P1),d(v,P2),…,d(v,Pt)), where d(v,Pi) represents the distance between the vertex vv and the set Pi. A partition Π of V is a resolving partition of G if different vertices of G have different partition representations, i.e., for every...
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Fading Modelling in Dynamic Off-Body Channels
PublicationThis paper presents an off-body fading channel model for Body Area Networks. The proposed model, based on both simulations and measurements at 2.45 GHz in a realistic indoor environment, consists of three components: mean path loss, body shadowing, and multipath fading. The first is modelled as a log function of distance, the path loss exponent being in between 0.4 and 1.6. A statistical perspective is taken for the other two components,...
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Method for Clustering of Brain Activity Data Derived from EEG Signals
PublicationA method for assessing separability of EEG signals associated with three classes of brain activity is proposed. The EEG signals are acquired from 23 subjects, gathered from a headset consisting of 14 electrodes. Data are processed by applying Discrete Wavelet Transform (DWT) for the signal analysis and an autoencoder neural network for the brain activity separation. Processing involves 74 wavelets from 3 DWT families: Coiflets,...
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Adaptive Method of Adjusting Flowgraph for Route Reconstruction in Video Surveillance Systems
PublicationPawlak’s flowgraph has been applied as a suitable data structure for description and anal- ysis of human behaviour in the area supervised with multicamera video surveillance system. Infor- mation contained in the flowgraph can be easily used to predict consecutive movements of a partic- ular object. Moreover, utilization of the flowgraph can support reconstructing object route from the past video images. However, such a flowgraph with...
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FINITE GROUND CPW-FED UWB ANTENNA OVER THE METALLIC CYLINDRICAL SURFACES
PublicationThe investigation of finite ground coplanar fed ultra-wideband (UWB) antenna and the influence of its curvature and the proximity of circular metallic screen on the reflection coefficients and radiation characteristics is presented. The antenna is composed of two circular coplanar strips which enclose slot aperture of similar shape and is designed on a thin and flexible substrate which allows its bending. The antenna configuration...
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Magnetoacoustic Heating of Plasma Caused by Periodic MagnetosoundPerturbations with Discontinuities in a Quasi-Isentropic Magnetic Gas
PublicationThe magnetoacoustic heating of plasma by harmonic or periodic saw-tooth perturbations at a trans-ducer is theoretically studied. The planar fast and slow magnetosound waves are considered. The wavevector may form an arbitrary angleθwith the equilibrium straight magnetic field. In view of variableθand plasma-β, the description of magnetosound perturbations and appropriate magnetosound heatingis fairly difficult. The scenario of...
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Dynamic Signal Strength Mapping and Analysis by Means of Mobile Geographic Information System
PublicationBluetooth beacons are becoming increasingly popular for various applications such as marketing or indoor navigation. However, designing a proper beacon installation requires knowledge of the possible sources of interference in the target environment. While theoretically beacon signal strength should decay linearly with log distance, on-site measurements usually reveal that noise from objects such as Wi-Fi networks operating in...
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Polynomial Algorithm for Minimal (1,2)-Dominating Set in Networks
PublicationDominating sets find application in a variety of networks. A subset of nodes D is a (1,2)-dominating set in a graph G=(V,E) if every node not in D is adjacent to a node in D and is also at most a distance of 2 to another node from D. In networks, (1,2)-dominating sets have a higher fault tolerance and provide a higher reliability of services in case of failure. However, finding such the smallest set is NP-hard. In this paper, we...
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Partition of friction heat between sliding semispaces due to adhesion-deformational heat generation
PublicationAnalytical expressions of heat-partition coefficient and contact temperatures for two sliding semispaces with account for adhesion-deformational heat generation and contact heat exchange have been obtained. The rate of deformational heat generation is assumed to decay exponentially with increase of distance from the interface. It has been shown that heat-generation configuration and the intensity of contact heat exchange have impact...
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Assessment of image processing methods for the determination of propagation of squat-type defects in rails
PublicationWe demonstrate the idea of squat-type defect measurement in the rail and the concept of tracking of the defect development using the techniques of image acquisition and image processing as well as the methods of metric spaces. We introduce the concepts of a set diameter δ(A) and the metric ρ1, which come from the properties of plane figures, to compare and to observe the development of the defects. We characterize the feasibility...
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Improving depth maps of plants by using a set of five cameras
PublicationObtaining high-quality depth maps and disparity maps with the use of a stereo camera is a challenging task for some kinds of objects. The quality of these maps can be improved by taking advantage of a larger number of cameras. The research on the usage of a set of five cameras to obtain disparity maps is presented. The set consists of a central camera and four side cameras. An algorithm for making disparity maps called multiple...
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A Broadband Circularly Polarized Wide-Slot Antenna with a Miniaturized Footprint
PublicationThis letter presents a novel and simple feeding technique for exciting orthogonal components in a wide-slot antenna. In this technique, a rectangular bracket-shape parasitic strip is placed at the open end of the straight microstrip line to excite the fundamental horizontal and vertical components of the circular polarization (CP). The proposed technique—when employed in conjunction with the asymmetrical geometry of coplanar waveguide...
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The relationship between phytochemical composition and biological activities of differently pigmented varieties of berry fruits; Comparison between embedded in food matrix and isolated anthocyanins.
PublicationThe aim of this research was to correlate the composition of phenolic compounds and bioactivities (antioxidant, cytotoxic, antigenotoxic, and influence on selected enzymatic activities) exhibited by extracts from differently pigmented raspberry (yellow and red), grape (white and red), mulberry (white and black), and currant (white, red, and black) varieties. It was presumed that phytocomplexes of the same species will be similar...
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W stronę spersonalizowanego miasta?
PublicationOd czasów Platona i Witruwiusza nie ustają wysiłki na rzecz dążenia do prawdy, dobra i piękna skupione wokół miasta jako idei politycznej i przestrzeni fundamentalnie egzystencjalnej. Towarzyszy im od wieków myślenie o idealnej organizacji i kompozycji miasta, o poczuciu podmiotowości mieszkańców i użytkowników, doświadczaniu przez nich czasu i przestrzeni. Szczególnie w ostatnich dekadach, gdy już nie przestrzeń, a czas i jego...
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Stability of trusses with linear elastic side-supports
PublicationThe present research is devoted to study of a lateral buckling of truss with linear elastic side supports. The elastic support reaction in relation to force in compressed chord and coefficient of buckling length related to side support distance are also calculated. The effect of slope of side support on limit force is also considered. The nonlinear analysis of two roof trusses are carried out. The results are compared to design...
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Validation of Interpolation Algorithms for Multiscale UV-VIS Imaging Using UAV Spectrometer
PublicationIn this study, we present a comparison of popular methods for the interpolation of irregular spatial data in order to determine the applicability of each algorithm for hyperspectral reflectance estimation. The algorithms were benchmarked against a very high-resolution orthoimage from an RGB camera and medium-resolution satellite imagery from Sentinel-2A. We tested five interpolation algorithms: Triangulated Irregular Network (TIN),...
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Predicting the seismic collapse capacity of adjacent SMRFs retrofitted with fluid viscous dampers in pounding condition
PublicationSevere damages of adjacent structures due to structural pounding during earthquakes have emphasized the need to use some seismic retrofit strategy to enhance the structural performance. The purpose of this paper is to study the influence of using linear and nonlinear Fluid Viscous Dampers (FVDs) on the seismic collapse capacities of adjacent structures prone to pounding and proposing modification factors to modify the median...
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Crystal structure and electronic structure of CePt2In7
PublicationWe report a corrected crystal structure for the CePt2In7 superconductor, refined from single crystal x-ray diffraction data. The corrected crystal structure shows a different Pt–In stacking along the c-direction in this layered material than was previously reported. In addition, all of the atomic sites are fully occupied with no evidence of atom site mixing, resolving a discrepancy between the observed high resistivity ratio of...
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PHONEME DISTORTION IN PUBLIC ADDRESS SYSTEMS
PublicationThe quality of voice messages in speech reinforcement and public address systems is often poor. The sound engineering projects of such systems take care of sound intensity and possible reverberation phenomena in public space without, however, considering the influence of acoustic interference related to the number and distribution of loudspeakers. This paper presents the results of measurements and numerical simulations of the...
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Capacity efficient shared protection and fast restoration scheme in self-configured optical networks
PublicationW artykule zaproponowano nową koncepcję optymalizacji rozdziału zasobów dla przeżywalnych sieci rozległych, która gwarantuje szybkie odtwarzanie usług po wystąpieniu awarii. Wykazano, iż proponowany algorytm, wykorzystujący ideę wierzchołkowego kolorowania grafów, nie powoduje wydłużania ścieżek zabezpieczających - zjawiska charakterystycznego dla powszechnie stosowanych algorytmów optymalizacji. Udowodniono, iż powyższa cecha...