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Search results for: DYWERSYFIKACJA HANDLU
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A Simple-Topology Compact Broadband Circularly Polarized Antenna With Unidirectional Radiation Pattern
PublicationIn this letter, a geometrically simple, reflector-backed single-point-fed circularly polarized (CP) antenna with unidirectional radiation pattern is presented. The structure comprises a simple coplanar waveguide (CPW) feeding circuit with an open slot etched on one side of the coplanar ground. The enhanced CP bandwidth is obtained by combining the loop mode, the slot mode, and the asymmetrical configuration of the coplanar ground...
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Coarse-grained simulation - an efficient approach for studying motions of large proteins
PublicationOne of the most important challenges in performing Molecular Dynamics (MD) simulations of large protein complexes is to accommodate the model accuracy and the simulation timescale. Hitherto, for the most relevant dynamics of protein aggregates in an explicit aqueous environment, the timescale reachable for the all-atoms simulations is of hundreds of nanoseconds. This range is four to six orders of magnitude smaller than processes...
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NUMERICAL MODEL QUALITY ASSESSMENT OF OFFSHORE WIND TURBINE SUPPORTING STRUCTURE BASED ON EXPERIMENTAL DATA
PublicationAs a structure degrades some changes in its dynamical behavior can be observed, and inversely, observation and evaluation of these dynamical changes of the structure can provide information of structural state of the object. Testing of the real structure, besides of being costly, can cover only limited working states. It is particularly considerable in case of hardly accessible, and randomly/severely dynamically loaded offshore...
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CMGNet: Context-aware middle-layer guidance network for salient object detection
PublicationSalient object detection (SOD) is a critical task in computer vision that involves accurately identifying and segmenting visually significant objects in an image. To address the challenges of gridding issues and feature...
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Organic pollutants photodegradation increment with use of TiO2 nanotubes decorated with transition metals after pulsed laser treatment
PublicationAmong various titanium(IV) oxide (TiO2, titania) structures, 1D nanotubes (TiO2 NTs) produced during the two-electrode anodization process, are extensively utilized in sensors or supercapacitors as well as in photo(electro)catalytic water splitting. However, due to wide bandgap and fast electron-hole recombination additional modifications, mostly concerned on materials surface, are required. According to the recent research, TiO2...
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Cost-Efficient Two-Level Modeling of Microwave Passives Using Feature-Based Surrogates and Domain Confinement
PublicationA variety of surrogate modelling techniques has been utilized in high-frequency design over the last two decades. Yet, the curse of dimensionality still poses a serious challenge in setting up re-liable design-ready surrogates of modern microwave components. The difficulty of the model-ing task is only aggravated by nonlinearity of circuit responses. Consequently, constructing a practically usable surrogate model, valid across...
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Rapid Design Centering of Multi-Band Antennas Using Knowledge-Based Inverse Models and Response Features
PublicationAccounting for manufacturing tolerances as well as uncertainties concerning operating conditions and material parameters is one of the important yet often neglected aspects of antenna development. Appropriate quantification of uncertainties allows for estimating the fabrication yield but also to carry out robust design (e.g., yield maximization). For reliability reasons, statistical analysis should be executed at the accuracy level...
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Usability of mobile applications: a systematic literature study
PublicationSince the release of the first mobile devices, the usability of on-board applications has been the concern not only of software vendors but hardware manufacturers as well. The academia community later willingly joined the discussion on usability in terms of theory and empirical measurement, having experience and knowledge in desktop settings. At first sight, such a background should guarantee a solid foundation to conduct research...
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Wyzwania bezpieczeństwa nowoczesnych platform nauczania zdalnego
PublicationW artykule zaprezentowano aspekty bezpieczeństwa nowoczesnych platform nauczania zdalnego. Przedstawiono ich charakterystykę i wyzwania technologiczne. Zdefiniowano bezpieczeństwo i istniejące w tym obszarze zagrożenia. Przybliżono metody oceny poziomu bezpieczeństwa. Na bazie wdrożonej na Politechnice Gdańskiej platformy eNauczanie PG omówiono sposoby zapewniania zakładanego poziomu bezpieczeństwa takich systemów.
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WARUNKI REZONANSOWE W WĘŹLE Z KOMPENSATOREM SVC
PublicationInstalowanie kompensatorów statycznych w sieciach rozdzielczych i przesyłowych służy poprawie profili napięciowych. Kompensatory jako źródła mocy biernej zwiększają stabilność napięciową systemu. Pozwalają także na szybszą odbudowę systemu w przypadku awarii napięciowej. W artykule zaprezentowano wpływ struktury i wysterowania układu SVC na zmianę impedancji w układzie zasilania. Ma to bezpośredni wpływ na częstotliwości, przy...
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Determining the noise impact on hearing using psychoacoustical noise dosimeter
PublicationThis research study presents the designed noise dosimeter based on psychoacoustical properties of the human hearing system and, at the same time. evaluation of time and frequency characteristics of noise. The designed noise dosimeter enables assessing temporary threshold shift (TTS) in critical hands in real time. In this way it is possible monitoring the hearing threshold shift continuously for people who stay in the harmful noise...
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On Unsupervised Artificial-Intelligence-Assisted Design of Antennas for High-Performance Planar Devices
PublicationDesign of modern antenna structures is a challenging endeavor. It is laborious, and heavily reliant on engineering insight and experience, especially at the initial stages oriented towards the devel-opment of a suitable antenna architecture. Due to its interactive nature and hands-on procedures (mainly parametric studies) for validating suitability of particular geometric setups, typical antenna development requires many weeks...
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Styrene-Butadiene Rubber/Modified Ground Tire Rubber Blends Co-Vulcanization: Effect of Accelerator Type
PublicationGround tire rubber was thermo-mechanically modified with using a co-rotating twin screw extruder. Modification of GTR was conducted in autothermal conditions. Styrene-butadiene rubber and modified ground tire rubber blends were prepared via two-roll milling. Obtained compounds were cured with conventional system (sulfur/vulcanization accelerator ratio was 2:1). During this research three commonly vulcanization accelerators (MBT,...
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The impact of security aspects on functional safety analysis = Wpływ aspectów ochrony informacji na wyniki analiz bezpieczeństwa funkcjonalnego
PublicationIt can be said that a distributed control and protection system’s security level may have a significant impact on functional safety analyses and their results. However the issue of integrating those both aspects are difficult and usually is neglected during functional safety analyses. Known methods of functional safety analyses don’t take into consideration this kind of concept also. This paper discusses an attempt to integrate...
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Polychlorinated biphenyls (PCBs) in bottom sediments: Identification of sources
PublicationPolychlorinated biphenyls (PCBs) can enter the environment from various sources. They are synthetic chemicals and as such are present in the environment mainly as mixtures containing various amounts of PCB congeners. It is therefore difficult to pinpoint the source of PCB emissions into the environment and the pathways along which they migrate there. The situation is different where locating the emission sources of polycyclic aromatic...
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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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Earthquake-Induced Structural Pounding
PublicationEarthquake-induced structural pounding between insufficiently separated build-ings, or bridge segments, has been repeatedly observed during ground motions. The reports after earthquakes indicate that it may lead to some local damage in the case of moderate seismic events or may result in considerable destruction or even collapse of colliding structures during severe ground motions. Pounding in build-ings is usually caused by the...
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Analytical methodologies for determination of artificial sweeteners in foodstuffs- a review
PublicationArtificial high-intensity sweeteners are more and more frequently used for food production. Food industry tends to highlight beneficial aspects of their use, such as tooth-friendliness, rising-up quality of life of those suffering from different forms of diabetes and possibility of weight control without sacrificing favorite unhealthy drinks or snacks. On the other hand some of the consumers are deeply concerned about safety of...
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Progress, Challenge, and Perspective of Bimetallic TiO2-Based Photocatalysts
PublicationBimetallic TiO2-based photocatalysts have attracted considerable attention in recent years as a class of highly active catalysts and photocatalysts under both UV and Vis light irradiation. Bimetallic noble metal structures deposited on TiO2 possess the ability to absorb visible light, in a wide wavelength range (broad LSPR peak), and therefore reveal the highest level of activity as a result of utilization of a large amount of...
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Objective selection of minimum acceptable mesh refinement for EMC simulations
PublicationOptimization of computational electromagnetics (CEM) simulation models can be costly in both time and computing resources. Mesh refinement is a key parameter in determining the number of unknowns to be processed. In turn, this controls the time and memory required for a simulation. Hence, it is important to use only a mesh that is good enough for the objectives of the simulation, whether for direct handling of high-fidelity EM...
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Molecular dynamics simulations of the affinity of chitin and chitosan for collagen: the effect of pH and the presence of sodium and calcium cations
PublicationChitosan and chitin are promising biopolymers used in many areas including biomedical applications, such as tissue engineering and viscosupplementation. Chitosan shares similar properties with hyaluronan, a natural component of synovial fluid, making it a good candidate for joint disease treatment. The structural and energetic consequences of intermolecular interactions are crucial for understanding the biolubrication phenomenon...
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The Motion Analysis of Attacus Atlas Rigid Wing
PublicationThe remarkable aerodynamic efficiency of flapping insect wings has fascinated researchers for many years. Butterfly wings are distinguished by a much larger lifting surface, and thus, a different style of flapping flight. The considerations described in the article are an introduction to a fully flexible analysis of the wing in motion. The study of the rigid wing gives the basic knowledge necessary in the further process. The yaw,...
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The Way One Defines Specification Matters: On the Performance Criteria for Efficient Antenna Optimization in Aggregated Bi-Objective Setups
PublicationDesign of antenna structures for real-world applications is a challenging task that often involves addressing multiple design requirements at a time. Popular solution approaches to this class of problems include utilization of composite objectives. Although configuration of such functions has a significant effect on the cost and performance of the optimization, their specific structure is normally determined based on engineering...
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On EM-driven size reduction of antenna structures with explicit constraint handling
PublicationSimulation-driven miniaturization of antenna components is a challenging task mainly due to the presence of expensive constraints, evaluation of which involves full-wave electromagnetic (EM) analysis. The recommended approach is implicit constraint handling using penalty functions, which, however, requires a meticulous selection of penalty coefficients, instrumental in ensuring optimization process reliability. This paper proposes...
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Detection and removal of priority substances and emerging pollutants from stormwater: case study of the Kołobrzeska collector, Gdańsk, Poland
PublicationProgressive urban development affects environmental balance and disrupts the hydrologic cycle, in which rainfall plays a significant role. Since rainwater is considered a valuable resource of the environment, many technical solutions are implemented that enable effective rainwater management. On the other hand, stormwater runoff from urban areas contains numerous (also toxic) substances, and therefore should be properly treated....
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Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media
PublicationThis work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to...
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New empirical correlations for the viscosity of selected organic phase change materials
PublicationAlthough there are many methods and instruments for measuring viscosity, it is still difficult to determine a reliable value of the dynamic viscosity of complex chemicals such as paraffins and fatty acids. This is due to the complex and heterogeneous structure of these compounds in the case of commercial products. On the other hand, the measuring instrument should be selected very carefully, including its measuring principle and...
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Silver(I) complexes with nitrile ligands: New materials with versatile applications
PublicationIn the present study, the structure, thermal stability, conductive properties, and antimicrobial activity of silver(I) complexes with nitrile ligands were investigated. For the construction of the materials, 2-cyanopyridine (2-cpy), 4-cyanopyridine (4-cpy), 1,2-dicyanobenzene (1,2-dcb), and 1,3-dicyanobenzene (1,3-dcb) were used in addition to the silver nitrite and nitrate. Four new compounds were isolated and structurally characterized:...
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Low-cost and reliable geometry scaling of compact microstrip couplers with respect to operating frequency, power split ratio, and dielectric substrate parameters
PublicationA technique for rapid re-design of miniaturised microstrip couplers with respect to operating conditions as well as material parameters of the dielectric substrate is proposed. The dimension scaling process is based on a set of pre-optimised reference designs, obtained for an equivalent circuit model of the coupler at hand. The reference designs are utilised to construct an inverse surrogate model which – upon suitable correction...
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Computational aspects of greedy partitioning of graphs
PublicationIn this paper we consider a variant of graph partitioning consisting in partitioning the vertex set of a graph into the minimum number of sets such that each of them induces a graph in hereditary class of graphs P (the problem is also known as P-coloring). We focus on the computational complexity of several problems related to greedy partitioning. In particular, we show that given a graph G and an integer k deciding if the greedy...
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Validating data acquired with experimental multimodal biometric system installed in bank branches
PublicationAn experimental system was engineered and implemented in 100 copies inside a real banking environment comprising: dynamic handwritten signature verification, face recognition, bank client voice recognition and hand vein distribution verification. The main purpose of the presented research was to analyze questionnaire responses reflecting user opinions on: comfort, ergonomics, intuitiveness and other aspects of the biometric enrollment...
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New achievements in the field of extraction of trace analytes from samples characterized by complex composition of the matrix
PublicationWithout any doubt, the monitoring of compounds present in samples at trace or ultra-trace level usually requires a preliminary step of isolation and/or enrichment of analytes due to the fact that majority of analytical techniques are not sensitive enough for direct determination of trace compounds. On the other hand, sample preparation is considered as crucial part of whole analytical procedures, in particular in samples characterized...
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Microencapsulation of fish oil – determination of optimal wall material and encapsulation methodology
PublicationFor the first time, we present a meta-analysis of experimental and literature data to determine which microencapsulation methodology, and which wall material are best suited to protect fish oil. Our analysis covered a period of several decades of research (1984–2018). The analysis was conducted on 196 literature data-points, and 16 data-points determined experimentally for this publication. PLS regression was used to determine...
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Comparative Greenness Evaluation
PublicationGreenness of analytical procedure is multivariable aspect as many greenness criteria should be taken into consideration. On the other hand, modern analytical chemistry offers dozens of analytical procedures, based on different sample preparation and final determination techniques that are used for the determination of a given analyte in a given matrix. For such complex decision-making processes, multi-criteria decision analysis...
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Heat recovery from the hybrid photovoltaic tile – experimental studies with the solar light simulator
PublicationConsidering the current development of micro-cogeneration energy sources, supported by the national prosumer policy and the act on the renewable energy sources, there is a great demand for the effective solar technologies. In this area, the photovoltaic cells with a combined conversion of the solar radiation energy into the electrical and thermal energy (PV/T cells) seem to be attractive. They are already widely available and treated...
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Building Information Modeling in Small and Middle Sized Buildings – Case Study
PublicationBuilding Information Modeling (BIM) is a technology designed to improve and integrate all engineering aspects in the construction design process. Tools that incorporate the idea of BIM are becoming more advanced and also more popular. Available software solutions have already reached an assumable high level of development, but still are not as widespread and used on nearly as many construction projects as could be expected. Therefore...
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The assessment of renewable energy in Poland on the background of the world renewable energy sector
PublicationThe issues of the article are associated with the development of the renewable energy source (RES) sector in the world and in Poland. The subject is undoubtedly connected with the problem of the energy transformation taking place in most countries nowadays. Energy transformation processes are mainly associated with an increase in the share of energy production from RES and increased awareness of energy use by end consumers. This...
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On weak solutions of the boundary value problem within linear dilatational strain gradient elasticity for polyhedral Lipschitz domains
PublicationWe provide the proof of an existence and uniqueness theorem for weak solutions of the equilibrium problem in linear dilatational strain gradient elasticity for bodies occupying, in the reference configuration, Lipschitz domains with edges. The considered elastic model belongs to the class of so-called incomplete strain gradient continua whose potential energy density depends quadratically on linear strains and on the gradient of...
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Participatory Budgeting in Poland – Missing Link in Urban Regeneration Process
PublicationIn last thirty years Poland has gone a long way toward democracy and decentralization. Role of public participation in planning is increasing rapidly and recently many new instruments of empowering the community is being introduced, participatory budgeting is one of the most important. On the other hand, urban regeneration is one of the most important challenges of polish cities are facing. Technical and transport infrastructure...
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EM‐driven constrained miniaturization of antennas using adaptive in‐band reflection acceptance threshold
PublicationNumerical optimization of geometry parameters is a critical stage of the design process of compact antennas. It is also challenging because size reduction is constrained by the necessity of fulfilling imposed electrical performance requirements. Furthermore, full‐wave electromagnetic (EM) analysis needs to be used for reliable performance evaluation of the antenna structure, which is computationally expensive. In this paper, an...
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A calibration model for gas sensor array in varying environmental conditions
PublicationAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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An Innovative Approach to the Forecasting of Energetic Effects While Wood Sawing
PublicationIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specifi c cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, the cutting forces (power) problem may be tackled with an innovative, up-to-date fundamental analysis of the mechanics of sawing based on modern fracture mechanics....
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Determining and verifying the safety integrity level of the safety instrumented systems with the uncertainty and security aspects
PublicationSafety and security aspects consist of two different group of functional requirements for the control and protection systems. In the paper it is proposed that the security analysis results can be used as a factor increasing or decreasing the risk level. It concerns a process of determining required safety integrity level of given safety functions. The authors propose a new approach for functional safety risk analysis. In this case...
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Nitrogen fraction fluctuation during wastewater treatment in a multistage treatment wetland
PublicationAlthough the size of pollutants discharged to a WWTP plays an important and often underestimated role in characterizing treat ability and hence the degree of contaminant removal of wastewater. From one hend In order to obtain efficient nitrogen removal in thedenitrification process, sufficient amounts of bioavailable carbon source should be ensured bur for the other hand in TWs, particulates from the wastewater are naturally trapped...
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Research Platform for Monitoring, Control and Security of Critical Infrastructure Systems
PublicationSustainable operation of Critical Infrastructure Systems (CISs) is of a major concern to modern societies. Monitoring, control and security of such systems plays a key role in guaranteeing continuous, reliable and above all secure access to the resources provided by these systems. Development of adequate software and hardware structures, as well as algorithms to perform such functions cannot be done apart from the operational conditions...
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An innovative approach to the forecasting of energetic effects while wood sawing
PublicationIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, the cutting forces (power) problem may be tackled with an innovative, up-to-date fundamental analysis of the mechanics of sawing based on modern fracture...
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Influence of electric, magnetic and electromagnetic fields on the circadian system – current stage of knowledge
PublicationOne of the side effects of each electrical device work is the electromagnetic field generated near its workplace. All organisms, including humans, are exposed daily to the influence of different types of this field, characterized by various physical parameters. Therefore, it is important to accurately determine the effects of an electromagnetic field on the physiological and pathological processes occurring in cells, tissues and...
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A calibration model for gas sensor array in varying environmental conditions
PublicationAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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Badania eksperymentalne modelu zbiornika stalowego na stole sejsmicznym = Experimental study on steel tank model using shaking table
PublicationCylindrical steel tanks are very popular structures used for storage of products of chemical and petroleum industries. Their safety and reliability is really crucial because any failure may have serious consequences. Earthquakes are the most dangerous and also the most unpredictable dynamic loads acting on such structures. On the other hand, rockburst-induced ground motions are usually considered to be less severe due to lower...
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The complexity of minimum-length path decompositions
PublicationWe consider a bi-criteria generalization of the pathwidth problem, where, for given integers k, l and a graph G, we ask whether there exists a path decomposition P of G such that the width of P is at most k and the number of bags in P, i.e., the length of P, is at most l. We provide a complete complexity classification of the problem in terms of k and l for general graphs. Contrary to the original pathwidth problem, which is fixed-parameter...