Filters
total: 2210
filtered: 2039
-
Catalog
Chosen catalog filters
displaying 1000 best results Help
Search results for: existence and uniqueness of solutions
-
Blockchain technologies to address smart city and society challenges
PublicationNew Information and Communications Technologies (ICT) are changing the way in which the world works. These technologies provide new tools to face the issues of contemporary society (poverty, migrations, sustainable development challenges, governance, etc.). Among them, blockchain emerge as a disruptive technology able to make things in a completely different and innovative way. They can provide solutions where before there were...
-
Challenges and opportunities related to the use of sewage sludge ash in cement-based building materials – A review
PublicationDue to the increasingly demanding legal regulations, regarding both sewage sludge (SS) and solid residues obtained during its thermal utilization processes, new solutions to limit their negative impact on the environment are sought. One approach that eliminates the risk of sewage sludge ash (SSA) is its use in cement building materials. The article contains a detailed literature review regarding the use of SSA in mortars and concretes,...
-
DMSO hydration redefined: Unraveling the hydrophobic hydration of solutes with a mixed hydrophilic–hydrophobic characteristic
PublicationHydrophobic hydration of solutes with a mixed hydrophilic--hydrophobic characteristics is still poorly understood. This is because both experimental and theoretical methods find it difficult to see the ice-like water structure around the nonpolar solute groups, unlike hydrogen bonds with the hydrophilic groups. In order to unravel this problem, we have investigated DMSO hydration by means of infrared spectroscopy and theoretical...
-
DETERMINATION OF OBJECTIVES FOR URBAN FREIGHT POLICY
PublicationBackground: Decisions regarding strategic planning of urban freight transport very often are based on superficial assumptions inadequately reflecting the actual character of encountered challenges. The trend may be observed to adapt isolated solutions without supporting measures and verification of expected outcomes. Selected urban freight solutions have a significant potential to alleviate transport related problems, but they...
-
Electrochemical cobalt oxidation in chloride media
PublicationThe green transition, despite recent advances in cobalt-free battery technologies, is still highly dependent on the availability of critical cobalt-based materials. Consequently, there has been increasing interest towards the development of new methods that maximize critical metals recovery from industrial hydrometallurgical solutions. In the current study, direct anodic oxidation of cobalt species from cobalt chloride solutions...
-
Reasons for Implementing Movement in Kinetic Architecture
PublicationThe paper gives insights into different forms of movement in contemporary architecture and examines them based on the reasons for their implementation. The main objective of the paper is to determine: the degree to which the complexity of kinematic architecture results from functional and spatial needs and what other motivations there are. The method adopted to investigate these questions involves theoretical studies and comparative analyses...
-
Theoretical analysis and experimental tests of tilting pad journal bearings with shoes made of polymer material and low-boiling liquid lubrication
PublicationSelecting the appropriate bearing system for the rotor requires a good knowledge of the available solutions and the operating conditions of the machine. For newly designed machinery operating in adverse conditions, selecting bearings that ensure correct and long-lasting operation can be extremely challenging. Difficulties in- crease when the machine’s operating parameters are beyond the technical capabilities of available technical solutions....
-
Thermal Energy Storage with PCMs in Shell-and-Tube Units: A Review
PublicationThe paper presents a survey of the experimental and numerical studies of shell-and-tube systems in which phase change material (PCM) is used. Due to the multitude of design solutions for shell-and-tube systems, the emphasis is placed on double-tube (DT), triplex-tube (TT), and multitube (MT) units. Additionally, only single-pass systems are considered. Particular attention is paid to the method of heat transfer intensification....
-
AI-powered Digital Transformation: Tools, Benefits and Challenges for Marketers – Case Study of LPP
PublicationThe article aims to show the role (benefits and challenges) of AI-powered digital marketing tools for marketers in the age of digital transformation. The considerations were related to the Polish market and a case study of LPP, a Polish clothing retailer. The starting point for this study was the analysis of the literature on the concept of artificial intelligence (AI) with reference to digital marketing. In the next steps, the...
-
Mieszanie w klasie niejednorodnych łańcuchów Markowa i kwadratowych operatorów stochastycznych
PublicationRozprawa doktorska poświęcona jest zagadnieniu asymptotycznych własności w klasie nieskończenie wymiarowych niejednorodnych łańcuchów Markowa z czasem dyskretnym oraz w klasie kwadratowych operatorów stochastycznych. W pierwszej kolejności definiowane są różne rodzaje asymptotycznego zachowania (mieszania) niejednorodnych łańcuchów Markowa odpowiadające zbieżności w normowej i mocnej topologii operatorowej oraz omówione są relacje...
-
Multidisciplinary Open System Transferring Knowledge for R2B Development
PublicationDespite many efforts, there is still a serious problem in transferring knowledge from research to business. The problem is especially visible in Poland – the cooperation of R2B is ineffective. We are trying to solve this problem using some IT support. The manuscript presents some solutions developed at the Gdańsk University of Technology. In particular, the platform called “MOST Knowledge” is deeply described. Its layer architecture,...
-
Progressive failure analysis of laminates in the framework of 6-field nonlinear shell theory
PublicationThe paper presents the model of progressive failure analysis of laminates incorporated into the 6-field non-linear shell theory with non-symmetrical strain measures of Cosserat type. Such a theory is specially recommended in the analysis of shells with intersections due to its specific kinematics including the so-called drilling rotation. As a consequence of asymmetry of strain measures, modified laminates failure criteria must...
-
A novel sandwich footbridge - Practical application of laminated composites in bridge design and in situ measurements of static response
PublicationA novel sandwich composite footbridge is presented in the paper, as an example of practical application of laminated composites in civil engineering. The in situ static load tests of the footbridge before its acceptation for exploitation are shown and discussed. The results are compared with the corresponding ones from a numerical equivalent single layer model of the sandwich structure created within the framework of finite element...
-
A Study in Experimental Methods of Human-Computer Communication for Patients After Severe Brain Injuries
PublicationExperimental research in the domain of multimedia technology applied to medical practice is discussed, employing a prototype of integrated multimodal system to assist diagnosis and polysensory stimulation of patients after severe brain injury. The system being developed includes among others: eye gaze tracker, and EEG monitoring of non-communicating patients after severe brain injuries. The proposed solutions are used for collecting...
-
SOLAP GIS in maritime research
PublicationMultidimensional Geographical Information System is a system especially designed to acquire, distribute, analyze and visualize complicated spatio-temporal data. Modern Geographical Information System technology can provide easy-to-use, near real-time solutions to many problems from different areas of research. In the article, authors summarize recent works on Spatial Online Analytical Processing (SOLAP) and multidimensional Geographical...
-
Iron(III)-selective materials based on a catechol-bearing amide for optical sensing
PublicationThe synthesis and ion-binding properties of a new amide L derived from 3,4-dihydroxybenzoic acid are described. Due to the presence of a catechol unit, the compound interacts selectively with iron(III) in organic solvent (dimethyl sulfoxide, DMSO) to produce a color change from pale yellow to green. The incorporation of the ligand L into polymeric matrices or its encapsulation into surfactant-based spheres enables analyte detection...
-
1D Model Callibration on the Basis on 3D calculations for Tesla Turbine
PublicationThe paper presents the system of equations for axisymmetriclaminar flow, after averaging, through the width of interdisk slit ofTesla turbine. Coefficients were introduced, as a result ofaveraging, that improve the efficiency of 1D model. The minimalnumber of such coefficients was determined. The 1D modelmakes it possible to attain analytical solutions to an accuracylimited by these coefficients. Calibration of 1D model depends...
-
Open-Set Speaker Identification Using Closed-Set Pretrained Embeddings
PublicationThe paper proposes an approach for extending deep neural networks-based solutions to closed-set speaker identification toward the open-set problem. The idea is built on the characteristics of deep neural networks trained for the classification tasks, where there is a layer consisting of a set of deep features extracted from the analyzed inputs. By extracting this vector and performing anomaly detection against the set of known...
-
Collaborative Data Acquisition and Learning Support
PublicationWith the constant development of neural networks, traditional algorithms relying on data structures lose their significance as more and more solutions are using AI rather than traditional algorithms. This in turn requires a lot of correctly annotated and informative data samples. In this paper, we propose a crowdsourcing based approach for data acquisition and tagging with support for Active Learning where the system acts as an...
-
Emulator and simulator of Terma SCANTER and ARPA radar data server
PublicationThe software solutions presented in this paper generate real-time data compatible with ARPA radar standard as well as Terma SCANTER 2001 radar cooperating with Video Distribution and Tracking (VDT) server. Two different approaches to this problem are considered: emulation based on the data captured from real devices and simulation of objects on the sea. For both of them architecture, implementation details and functional test results...
-
On the instantaneous frequency smoothing for signals with quasi-linear frequency changes
PublicationThe problem of estimation of the slowly-varying instantaneous frequency of a nonstationary complex sinusoidal signal buried in noise is considered. This problem is usually solved using frequency tracking algorithms. It is shown that the accuracy of frequency estimates can be considerably increased if the results yielded by the frequency tracker are further processed using the appropriately designed filters. The resulting frequency...
-
Performance analysis of an rfid-based 3d indoor positioning system combining scene analysis and neural network methods
PublicationThe main purpose of this research is to improve localization accuracy of an active Radio Frequency Identification, RFID tag, in 3D indoor space. The paper presents a new RFID based 3D Indoor Positioning System which shows performance improvement. The proposed positioning system combines two methods: the Scene Analysis technique and Artificial Neural Network. The results of both simulation using Log-Distance Path Loss Model and...
-
Implementation of the digital receiver in multibeam long-range sonar
PublicationThe article presents the implementation of a digital receiver in multibeam long - range sonar. Developed by the authors of the article, the implementation was part of sonar modernisation on large Polish Navy ships. The article explains the structure of the receiver, its design details and requirements affecting the architecture. The technical solutions regarding the equipment and signal processing algorithms for determining receiving...
-
Numerical solution of fractional neutron point kinetics in nuclear reactor
PublicationThis paper presents results concerning solutions of the fractional neutron point kinetics model for a nuclear reactor. Proposed model consists of a bilinear system of fractional and ordinary differential equations. Three methods to solve the model are presented and compared. The first one entails application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. Second involves building an analog scheme...
-
Schematiclab.com – A web tool for the design and analysis of electrical circuits
PublicationAlong with a general progress in the modern computational tools, dynamic development of Internet applications using the cloud methodology and solutions is now observed. Clearly, also the applications installed locally, and being commonly used previously, are gradually gaining their counterparts in computational network clouds. The clouds have also brought new service sales opportunities. Namely, the service sales model based on...
-
Reliability And Safety As An Objective Of Intelligent Transport Systems In Urban Areas
PublicationTechnologies that use transport telematics offer tools for strengthening urban transport systems. They rationalise the use of the existing infrastructure and transport management systems, increase their reliability and safety and improve the transport behaviour of residents, while reducing the operating costs of transport. The main reason for using Intelligent Transport Systems (ITS) is the need to implement measures to reduce...
-
Conductivity and viscosity changes of imidazolium ionic liquids induced by H2O and CO2
PublicationSeveral solutions of ionic liquids based on 1-ethyl-3-methylimidazolium cation saturated and unsaturated with carbon dioxide were prepared and characterized by electrochemical impedance spectroscopy. The in fluence of ILs saturation on its electrical conductivity was determined. Additionally, the in fluence of the water presence and variations of temperature on electrical properties of ionic liquids were investigated. Changes of...
-
Action-reaction based synthesis of acoustic wavefield equations
PublicationThe analysis of acoustic fields is usually based on the well-known mathematics of second order partial differential equations called wave equations. The author explores the duality and symmetry of linear fluid mechanics and develops two distinct equations of acoustics on the basis of a causal approach to local small-scale phenomena. Wavefields that are solutions of these equations have different composition, the spherical pressure...
-
Theoretical analysis of the cable-stayed bridge over brda river in Bydgoszcz
PublicationThe topic of this article is the numerical analysis carried out for the cable-stayed tram (road) bridge over Brda river in Bydgoszcz. The goal of numerical studies was the verification of project assumptions and construction solutions elaborated by the autonomous team. The bridge calculations were conducted on three independent FEM models The internal forces and the elements effort under different loading schemes were examined....
-
Hybrid piezoelectric motor based on electroactive lubrication principle
PublicationA novel conception of hybrid piezoelectric motor is presented in this paper. Proposed conception required synchronised work of quasi-static and resonant piezoelectric actuators that results in a rotary movement. The motor's working principle is explained and the main characteristics are described. Studied topology is compared to the existing piezoelectric motors with regards to its field of applications. The assembling process...
-
Numerical estimation of the pile toe and shaft unit resistances during the installation process in sands
PublicationNumerical simulations of a pile jacking were carried out. A Coupled Eulerian–Lagrangian (CEL) formulation was used to treat with large deformation problems. An Abaqus, a commercial Finite Element Method software suit, was used as a computing environment. The Mohr–Coulomb constitutive model was applied and the Coulomb model of friction was used to describe pile-soil interaction. Calculations were made for three different pile diameters....
-
Minimum drag shape bodies moving in inviscid fluid - revisited
PublicationThis paper presents the classic approach to minimum drag shape body problem, moving at hypersonic speeds, leading to famous power law shapes with value of the exponent of 3/4. Two- and three-dimensional cases are considered. Furthermore, an exact pseudo solution is given and its uselessness is discussed. Two new solutions are introduced, namely an approximate solution due to form of the functional and solution by means of optimisation...
-
Qualitative evaluation of distributed clinical systems supporting research teams working on large-scale data
PublicationInthispaper,fivecontemporaryscalablesystemstosupportmedicalresearchteams are presented. Their functionalities extend from heterogeneous unstructured data acquisition through large-scale data storing, to on-the-fly analyzing by using robust methods. Such kinds of systems can be useful in the development of new medical procedures and recommendation rules for decision support systems. A short description of each of them is provided....
-
A Stand for Measurement and Prediction of Scattering Properties of Diffusers
PublicationIn 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...
-
Renovation works in buildings in the area of former defensive fortifications
Publicationhe paperpresents the Complex of Buildings which was created in Gdańsk as a result of the reconstruction and development of the remains of the defensive fortifications of Redita Napoleońska. Some of the buildings of the Building Complex, after many years of operation, were in an emergency condition and required urgent renovation and repair work. The papercontains a detailed analysis of the technicalcondition of individual...
-
Design analysis of Tesla micro-turbine operating on a low-boiling medium
PublicationThis paper presents results of the design analysis of a Tesla bladeless turbine intended for a co-generating micro-power plantof heat capacity 20 kW, which operates in an organic Rankine cycle on a low-boiling medium. Numerical calculations of flowin several Tesla turbine models were performed for a range of design parameters. Results of investigations exhibit interestingfeatures in the distribution of flow parameters within the...
-
Wpływ ekologicznych czynników roboczych na efektywność układu sprężarkowej pompy ciepła (The impact of environmentally friendly refrigerants on heat pump efficiency)
PublicationArtykuł poświęcony jest zagadnieniu symulacji pracy układu sprężarkowej pompy ciepła. Prawidłowe zaprojektowanie instalacji oraz jej właściwe użytkowanie pozwala na zmniejszenie kosztów eksploatacji. Dokładna analiza techniczno-ekonomiczna umożliwia natomiast dobór elementów systemu o możliwie największej sprawności, a zatem niskim zapotrzebowaniu na energię. Zastosowanie układów opartych o perspektywiczne, proekologiczne czynniki...
-
Limiting Partial Molar Volumes of Tetra-n-Alkylammonium Perchlorates in N,N-dimethylacetamide, Triethylphosphate and Dimethyl Sulfoxide at 298.15 K
PublicationThe densities of tetraalkylammonium perchlorates R4NClO4(R = methyl, or ethyl, or propyl, or butyl) and ammonium perchlorate solutions in N, N - dimethylacetamide, dimethyl sulfoxide, and triethylphosphate have been measured over the whole composition range atT = 298.15 K. From these densities, apparent and limiting partial molar volumes of the electrolytes and ions...
-
Concept of the agent system for the information technology evaluation
PublicationIn this paper the concept of the agent system for the information technology evaluation has been presented. This article includes the concept description and shows abilities of using software tools which can be applicable to implementation and verification of proposed solution. The article is the part of common researches over creation solutions for information technology evaluation which range over using expert's evaluation and...
-
Shaping of the turnout diverging track with variable curvature sections
PublicationThe paper presents an analytical method of shaping the turnout diverging railroad track with variable curvature segments on its length, which in an evident way distinguished it from a typical solution, made up of a single circular arc with no transition curves. Two separate causes including a linear and a nonlinear curvature one in the form of a polynomial have been examined. The obtained solutions of the problem have a universal...
-
Hybrid stepless distribution transformer with four-quadrant AC/DC/AC converter at low voltage side - simulation tests
PublicationThe article presents the work of the stepless hybrid distribution transformer (HT), as an alternative to the so far applied Automatic Voltage Regulator (AVR) solutions, used to control the voltage in the power system in terms of the fundamental harmonic. The HT is a combination of a conventional distribution transformer and an AC/DC/AC converter connected in series with the transformers secondary winding. In the work the basic...
-
OSC - domain oriented ontology creation system
PublicationOntologies are, as part of semantic web, a basic component to enrich content available in the Internet with a meaning understandable for computers. In this publication an architecture and functionality of a domain oriented web portal for collaborative creation and storage of ontologies is presented. The system is being created by Gdańsk University of Technology Electronics, Telecommunications and Informatics faculty's Department...
-
Fluctuation-Enhanced Sensing (FES): A Promising Sensing Technique
PublicationFluctuation-enhanced sensing (FES) is a very powerful odor and gas sensing technique and as such it can play a fundamental role in the control of environments and, therefore, in the protection of health. For this reason, we conduct a comprehensive survey on the state-of-the-art of the FES technique, highlighting potentials and limits. Particular attention is paid to the dedicated instrumentation necessary for the application of...
-
Hybrid Method Analysis of Unshielded Guiding Structures
PublicationA combination of mode matching, finite element methods and generalized impedance matrix is presented in a context of propagation problems for open guiding structures. The computational domain is divided into two regions: the first one is a circular cylinder containing whole guiding structure and the second one surrounds this artificial cylinder. The impedance matrix is calculated with the use of finite element method in the first...
-
Estimators of covariance matrices in Msplit(q) estimation
PublicationThis paper proposes methods for the determination of covariance matrices of Msplit(q) estimators. The solutions presented here allow Msplit(q) estimation to be supplemented by the operations from the domain of accuracy analysis (especially that concerning estimators of parameters). Theoretical forms of covariance matrices of Msplit(q) estimators were established using the empirical influence functions and the equivalent covariance...
-
Innovative design of hybrid powered inland vessel
PublicationOne of the most demanding task for European countries is rational transportation system taking into account fuel efficient and ecological propulsion. The paper presents innovative design of hybrid powered inland vessel. The most important aspects regarding new design and technical solutions are being presented, including numerical and experimental research on hull form. Combined diesel-electric propulsion supported by solar panel...
-
SMAQ - A Semantic Model for Analitical Queries
PublicationWhile the Self-Service Business Intelligence (BI) becomes an important part of organizational BI solutions there is a great need for new tools allowing to construct ad-hoc queries by users with various responsibilities and skills. The paper presents a Semantic Model for Analytical Queries – SMAQ allowing to construct queries by users familiar with business events and terms, but being unaware of database or data warehouse concepts...
-
Genetic Programming with Negative Selection for Volunteer Computing System Optimization
PublicationVolunteer computing systems like BOINC or Comcute are strongly supported by a great number of volunteers who contribute resources of their computers via the Web. So, the high efficiency of such grid system is required, and that is why we have formulated a multi-criterion optimization problem for a volunteer grid system design. In that dilemma, both the cost of the host system and workload of a bottleneck host are minimized. On...
-
Fractional neutron point kinetics equations for nuclear reactor dynamics – Numerical solution investigations
PublicationThis paper presents results concerning numerical solutions to a fractional neutron point kinetics model for a nuclear reactor. The paper discusses and expands on results presented in (Espinosa-Paredes et al., 2011). The fractional neutron point kinetics model with six groups of delayed neutron precursors was developed and a numerical solution using the Edwards’ method was proposed (Edwards et al., 2002). The mathematical model...
-
Rotational Design Space Reduction for Cost-Efficient Multi-Objective Antenna Optimization
PublicationCost-efficient multi-objective design of antenna structures is presented. Our approach is based on design space reduction algorithm using auxiliary single-objective optimization runs and coordinate system rotation. The initial set of Pareto-optimal solutions is obtained by optimizing a response surface approximation model established in the reduced space using coarse-discretization EM simulation data. The optimization engine is...