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Wyniki wyszukiwania dla: CRITICAL BUCKLING LOAD
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Seismic performance evaluation of steel buckling-restrained braced frames including SMA materials
PublikacjaThe permanent deformation of the building after seismic excitations can be determined by the Maximum Residual Interstory Drift Ratio (MR-IDR), which may be used for measuring the damage states. Low-post yield stiffness of the steel buckling-restrained braced frame (BRBF) makes this system vulnerable to large MR-IDR after a severe earthquake event. To overcome this issue, this paper investigates the seismic limit state performances...
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Finite element models used in diagnostics of transverse cracks in bridge approach pavement
Dane BadawczeTransverse cracks in the asphalt pavement were observed on bridge structures next to single-module expansion joints with a 5 meter approach slab set at the depth of 1 m. The finite element (FE) models of the approach pavement were created to investigate the reasons of premature cracking and crack initiation mechanism over the back edge of the abutment...
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DEFORMATIONS OF INNOVATIVE COLD-FORMED GEB SECTIONS
PublikacjaPermanent urban growth of the world of today world implies demanding challenges for the steel construction industry. Nowadays, one of the most important issues is the cost optimization of steel structures. Since the weight of building materials is a major component of the total cost, engineers and designers try to reduce structural weight, without compromising durability and sustainability of a steel structure. Therefore, light...
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Wpływ imperfekcji geometrycznych na bezpieczeństwo montażu i naprawy zbiorników cylindrycznych metoda podbudowy
PublikacjaW pracy zajęto się wyznaczeniem nośności granicznej zbiorników stalowych o osi pionowej montowanych lub naprawianych z zastosowaniem hydraulicznego systemu podnoszenia konstrukcji. Podniesiony zbiornik jest szczególnie narażony na utratę stateczności, a obciążenie wiatrem utrudnia prowadzenie prac. Jakiekolwiek deformacje blach, szczególnie w pobliżu zamocowań podnośników mogą w znacznym stopniu obniżyć obciążenie krytyczne konstrukcji....
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A new hyperbolic-polynomial higher-order elasticity theory for mechanics of thick FGM beams with imperfection in the material composition
PublikacjaA drawback to the material composition of thick functionally graded materials (FGM) beams is checked out in this research in conjunction with a novel hyperbolic‐polynomial higher‐order elasticity beam theory (HPET). The proposed beam model consists of a novel shape function for the distribution of shear stress deformation in the transverse coordinate. The beam theory also incorporates the stretching effect to present an indirect...
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Seismic response and performance prediction of steel buckling-restrained braced frames using machine-learning methods
PublikacjaNowadays, Buckling-Restrained Brace Frames (BRBFs) have been used as lateral force-resisting systems for low-, to mid-rise buildings. Residual Interstory Drift (RID) of BRBFs plays a key role in deciding to retrofit buildings after seismic excitation; however, existing formulas have limitations and cannot effectively help civil engineers, e.g., FEMA P-58, which is a conservative estimation method. Therefore, there is a need to...
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Numerical Analysis of Mice Carotid Arteries’ Response Emphasizing the Importance of Material Law Constants’ Validation
PublikacjaIn this paper, a detailed validation of the passive material properties of mice carotid arteries and constants of the Fung and Holzapfel hyperelastic material laws is conducted by means of static nonlinear FEM analyses. The response of the carotid arteries in an inflation test is studied here for the following mouse models: wild-type, mdx, sgcd−/−, Eln+/+, Eln+/−, Fbln5+/+, and Fbln5−/−. All FEM computations are conducted on models...
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Safety-Critical Systems 2023
Kursy OnlineSafety-Critical Systems / Bezpieczeństwo systemówKierunek Informatyka, studia II stopniaProwadzący: Andrzej WardzińskiWykład: Poniedziałek 15:15 EA 07 (od 27 lutego 2023)Projekt w drugiej połowie semestruKod dostępu do przedmiotu w eNauczanie będzie przekazany podczas pierwszego wykładu
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Safety-Critical Systems 2023
Kursy OnlineSafety-Critical Systems / Bezpieczeństwo systemówKierunek Informatyka, studia II stopnia Prowadzący: Andrzej Wardziński Wykład: Poniedziałek 15:15 EA 07 (od 27 lutego 2023) Projekt w drugiej połowie semestru Kod dostępu do przedmiotu w eNauczanie będzie przekazany podczas pierwszego wykładu
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CRITICAL REVIEWS IN ANALYTICAL CHEMISTRY
Czasopisma -
Launching of steel bridge girder. Application of nonlinear shell models
PublikacjaThe paper describes the final technology of launching the steel bridge superstructure. The original technology failed in the first construction stage. Local damage of steel webs caused by plastic buckling stopped the procedure. In the effect of damage a new consulting team was employed to solve the problem and redesign a technology of constructing. The key element of the new solution was developed with great help of non-linear...
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SHM System of the Roof Structure of Sports Arena “Olivia”
PublikacjaThe paper presents a structural health monitoring system of the Sports Arena “Olivia” in Gdansk, Poland. The system was installed because of doubts about the roof stability due to observed buckling of the steel truss members. The SHM system was based on nonlinear FEM models used for detection of type of near failure modes of the roof. The application of detailed FEM model in current state updated on data from in situ loading testes...
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On a flexomagnetic behavior of composite structures
PublikacjaThe popularity of the studies is getting further on the flexomagnetic (FM) response of nano-electro-magneto machines. In spite of this, there are a few incompatibilities with the available FM model. This study indicates that the accessible FM model is inappropriate when considering the converse magnetization effect that demonstrates the necessity and importance of deriving a new FM relation. Additionally, the literature has neglected...
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Buckling of braced frames
PublikacjaIn this paper the classical Winter model, developed originally for columns is applied for frame structures and compared with the results of parametric study of frame with bracing. Sensitivity analysis of critical loads of frame due to bracing stiffness is carried out and the threshold bracing stiffness for full bracing is found. In the non-linear statical analysis the forces in bracings are calculated.
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Jacek Namieśnik prof. dr hab. inż.
OsobyUrodził się 10 grudnia 1949 r. w Mogilnie, zmarł 14 kwietnia 2019 r. w Gdańsku – polski chemik, profesor nauk chemicznych, specjalizujący się w chemii analitycznej i środowiskowej. Rektor Politechniki Gdańskiej w latach 2016–2019. Studia wyższe ukończył w 1972 r. na Wydziale Chemicznym Politechniki Gdańskiej, uzyskując tytuł magistra inżyniera chemika. W 1972 r. rozpoczął pracę na Politechnice Gdańskiej, gdzie w 1978 r. obronił...
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Wpływ równości nawierzchni i dynamicznego oddziaływania pojazdów ciężkich na trwałość zmęczeniową nawierzchni podatnych
PublikacjaPodczas ruchu pojazdu obserwuje się odchylenia nacisków osi pojazdów od nacisku statycznego, co jest spowodowane nierównościami nawierzchni. Dynamiczne obciążenia pojazdów w większym stopniu wytężają konstrukcję nawierzchni drogowej. Rozkład obciążeń dynamicznych ma kształt rozkładu normalnego i jest opisywany poprzez obciążenie statyczne oraz wskaźniki dynamiczne DI lub DLC. Wraz z pogorszeniem równości i zwiększeniem prędkości...
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Critical systems software testing and QA - Spring'24
Kursy OnlineCourse objectives: Present software development standards in the European space industry and techniques of their implementation. Learn how to assess and manage critical system software quality in an IT project. Gain basic hands-on experience in bug tracking and reporting in a software project.
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Thin-walled cross section shape influence on steel member resistance.
PublikacjaThis work describes why trending thin-walled technology is achieving popularity in steel construction sector. A purpose of this article is to present the influence of the cold-formed element cross-section shape on an axial compression and a bending moment resistance. The authors have considered four different shapes assuming constant section area and thickness. Calculations were based on three different steel grades taking into...
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8. Critical Management Studies
Kursy Online -
Safety-Critical Systems 2024
Kursy OnlineCelem przedmiotu jest pozyskanie zrozumienia procesu zarządzania bezpieczeństem systemów, stosowanych metod zapewnienia bezpieczeństwa oraz umiejętności analizy bezpieczeństwa systemu zawierającego oprogramowanie. Wykład: poniedziałek, godz. 11:15, sala EA 31
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Determination of equivalent axle load factors with the use of strain energy of distortion
PublikacjaThe paper proposes a new method for calculation of equivalent axle load factors based on the analysis of strain energy of distortion induced in road pavements by traffic loads. The main advantage of the method is the more accurate calculation of the effects of multiple axles and super single versus dual tyres. The methodconsiders the location of critical points, at which strain energy of distortion reaches extreme values. When...
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Selected Stability Problems of Thin-Walled Columns and Beams
PublikacjaThe article reviews a number of papers in the light of buckling analy- sis of thin-walled columns and beams. Stability of thin-walled columns and beams are considered a vital engineering science issue in both historical and present-day approaches. The paper refers to the recent authors’ works of the 2012–2019 period, published in leading journals. Similar review of stability problems of thin-walled structures developed at Gdansk...
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Simplified stability analysis of steel cylindrical silos with corrugated walls and vertical columns
PublikacjaIn the paper a simplified stability analysis of steel cylindrical silos composed of corru¬gated walls and vertical open-sectional columns was proposed. The whole 3D silo was modeled as a single column resting on elastic foundation provided by the silo walls. In proposed formula for the calculation of the foundation stiffness the curvature of the silo walls was taken into account. Three different analyses were carried out using...
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Rafał Leszczyna dr hab. inż.
OsobyDr hab. inż. Rafał Leszczyna jest profesorem uczelni na Wydziale Zarządzania i Ekonomii Politechniki Gdańskiej. W lipcu 2020 r., na podstawie osiągnięcia naukowego w obszarze zarządzania cyberbezpieczeństwem infrastruktur krytycznych w sektorze elektroenergetycznym, uzyskał stopień doktora habilitowanego w dziedzinie nauk inżynieryjno-technicznych, dyscyplina informatyka techniczna i telekomunikacja. W latach 2004–2008 pracował...
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Load function walking pedestrian on the footbridge.
PublikacjaModern foot bridges are more and more sensitive to variable load created by moving pedestrians. These are several reasons for that. Quickly growing up road infrastructure forces us to build foot bridges just to reconnect one piece of land, separated now by the new road or railway. These bridges are lightweight because the only live load acting on them comes from pedestrians.The paper focuses on the definition of human induces dynamic...
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Enhancing Availability for Critical Services
PublikacjaTraditional approaches to provide classes of resilient service take the physical network availability as an input and then deploy redundancy and restoration techniques at various layers, often without full knowledge of mappings between layers. This makes it hard (and often inefficient) to ensure the high availability required by critical services which are typically a small fraction of the total traffic. Here, the innovative technique...
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Towards Agile Development of Critical Software
PublikacjaThe paper presents a case study aiming at collecting opinions of software en-gineers on the risks related to integration of agile practices to safety-critical software development projects. The study has been performed within the scope of our research targetting at providing critical software developers with a comprehensive solution allowing to incorporate agile practices into software development process while still being conformant...
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The flux compression generator load parameters selection
PublikacjaComputer simulation results of the flux compression generator (FCG) loaded with an inductor has been presented in this paper. Simulation research has been performed in order to select the parameters of FCG load coil properly. The influence of the load inductance and resistance on the current gain factor and the magnetic field energy accumulated in a load coil has been investigated.
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Właściwości niskotemperaturowe betonów asfaltowych o wysokim module sztywności (AC-WMS) w badaniach trzypunktowego zginania
PublikacjaArtykuł przedstawia właściwości niskotemperaturowe betonów asfaltowych o wysokim module sztywności. Przedstawione wyniki zostały uzyskane w dwóch badaniach zginania trzypunktowego próbek belkowych: ze stałą prędkością przemieszczenia oraz pod stałym obciążeniem. Obie te metody są od dawna stosowane na Politechnice Gdańskiej do oceny właściwości niskotemperaturowych betonów asfaltowych. Badaniu poddano pięć betonów asfaltowych –...
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System load impact on VRRP advertisements delay
PublikacjaThe aim of the paper is to show how system load can affect network tasks (especially VRRP advertising depending on factors such as kernel schedu-ler [3] version, kernel settings and load priority. Two versions of the Linux kernel will be used: 2.6.22 (with "O(1) scheduler) and 2.6.23 (with "CFS" scheduler). "vrrpd" version 0.4 is used as an VRRP protocol implementation.
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Calculation of an ultimate load value of a silo with geometric imperfections in the shape of eigenforms
PublikacjaThe ultimate load value of a silo with initial geometric imperfections was measured. The structure was loaded with wind. Imperfections were assumed as translations of the shell nodes from perfect geometry taken from eigenforms and their combinations. Two variants of the maximum deflection placement with respect to the direction of wind pressure were proposed. The first consists in applying the maximum wind pressure to the element...
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Agile Development of Critical Software - Can It be Justified?
PublikacjaThe paper introduces the problem of application of agile practices in critical software development projects. It summarizes the present state of research and identifies the need for having a ready-to-use model of being agile while still meeting the required assurance levels which could be particularly useful for small and medium sized safety-critical software companies. Then the objective and scope of a research aiming at delivering...
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A method of nonlinearities of transformer no-load characteristic modelling
PublikacjaA way in which changes of the no-load characteristic are taken into account in the mathematical model of the transformer is presented. Changes of saturation within core of transformer are presented as a combined non-linear flux curve. Analysis of magnetization of the transformer core and simulation of no-load state for distribution transformer of 30 kVA power rating and 15.75/0.4 kV/kV (especially supplying VLV) transformation...
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Load-settlement characteristics of piles working in a group
PublikacjaLoad-settlement characteristic (Q-s) of an axially loaded pile can be empirically determined from a static pile load test or on the basis of calculations using, e.g. transfer functions or numerical methods (FEM). The transfer functions method usually rely on empirical data, i.e. the function parameters are determined on the basis of numerous pile test results. Thus this method takes into account pile installation technology and...
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Rigorous numerics for critical orbits in the quadratic family
PublikacjaWe develop algorithms and techniques to compute rigorous bounds for finite pieces of orbits of the critical points, for intervals of parameter values, in the quadratic family of one-dimensional maps fa(x)=a−x2. We illustrate the effectiveness of our approach by constructing a dynamically defined partition P of the parameter interval Ω=[1.4,2] into almost 4 million subintervals, for each of which we compute to high precision the...
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Applying agiile practices to the development of safety-critical software
PublikacjaDevelopment of safety critical software is subjected to numerous restrictions and recommendations. To meet these requirements classical software development models (e.g. V-model) are usually applied. Agile methodologies, although rapidly increasing their popularity, were generally regarded as unsuitable for such projects. However, they offer potential benefits which provide a strong incentive to incorporate them into safety-critical...
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Security Evaluation of IT Systems Underlying Critical Networked Infrastructures
PublikacjaCritical infrastructures have become highly dependent on information and communication technology (ICT). The drawback of this situation is that the consequences of disturbances of the underlying ICT networks may be serious as cascading effects can occur. This raises a high demand for security assurance, with a high importance assigned to security evaluations. In this paper we present an experiment-centric approach for the characterisation...
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Approach to evaluation of time to the critical degradation of ship pipelines
PublikacjaIn the article an approach to the problem of estimating time to the critical degradation of ship pipelines is considered. Such an assessment would consist of six stages. The fundamental idea is to include to the estimation of time to failure of pipelines such elements like: materials that the pipelines are made, destructive physical phenomena taking place in them and applied means of protection. The result of that evaluation should...
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Korzyści z zastosowania układów Load Sensing
PublikacjaW artykule porównano układy Load Sensing I i II rodzaju z układem z dwudrogowym regulatorem przepływu. Dokonano oceny mocy traconych oraz korzyści stosowania układów LS w stosunku do tradycyjnych rozwiązań
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Load effect impact on the exploitation of concrete machine foundations used in the gas and oil industry
PublikacjaMachine foundations is a critical topic in the gas and oil industry, which design and exploitation require extensive technical knowledge. Machine foundations are the constructions which are intended for mounting on it a specific type of machine. The foundation has to transfer dynamic and static load from machine to the ground. The primary difference between machine foundations and building foundations is that the machine foundations...
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CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Czasopisma -
Agents in Simulation of Cyberattacks to Evaluate Security of Critical Infrastructures
PublikacjaIn the last years critical infrastructures have become highly dependent on the information technologies and exposed to cyberattacks. Because the effects of the attacks can be detrimental, it is crucial to comprehensively asses the security of the infrastructures' information systems. This chapter describes MAlSim - the simulator of malicious software based on software agents, developed for the needs of a testbed for critical infrastructures...
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Underfrequency Load Shedding: An Innovative Algorithm Based on Fuzzy Logic
PublikacjaIn contemporary power systems, the load shedding schemes are typically based on disconnecting a pre-specified amount of load after the frequency drops below a predetermined value. The actual conditions at the time of disturbance may largely dier from the assumptions, which can lead to non-optimal or ineective operation of the load shedding scheme. For many years, increasing the eectiveness of the underfrequency load shedding (UFLS)...
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Multisensor System for the Protection of Critical Infrastructure of Seaport
PublikacjaThere are many separated infrastructural objects within a harbor area that may be considered “critical”, such as gas and oil terminals or anchored naval vessels. Those objects require special protection, including security systems capable of monitoring both surface and underwater areas, because an intrusion into the protected area may be attempted using small surface vehicles (boats, kayaks, rafts, floating devices with weapons...
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Wireless Networks as an Infrastructure for Mission-Critical Business Applications
PublikacjaDespite the dynamic growth of wireless network systems, their pres-ence in business-support infrastructure has been limited. In the article we provide an overview of generic corporate network architecture and examine usefulness of available wireless network solutions in such systems. Following this overview we analyze new wireless network architecture which currently undergoes standardization process - wireless mesh. It can result...
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Analysis of the Impact of Charging Electric Cars on the Power System Load
PublikacjaThe paper presents ways of integrating electric cars with the power system. In connection with this, daily load curves in the average working day have been developed in the G2V (Grid-to-Vehicle) and V2G (Vehicle-to-Grid) variants. The G2V solution consists in unidirectional energy flow from the power system to a vehicle’s battery. The V2G solution consists in bi-directional energy exchange between the power system and electric...
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Experimental study and numerical optimization of tensegrity domes – A case study
PublikacjaThe paper deals with the design, experimental analysis and numerical optimization of tensegrity dome models. Two structures are analyzed – a Geiger system dome (preliminary dome), with PVC-U bars and PA6/PP/PET tendons and a Fuller system dome (target dome), with wooden bars and steel cables as tendons. All used materials are experimentally tested in terms of Young's modulus and yield stress values, the compressed bars are also...
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Buckling and post-buckling behavior of column with central non-linear restraint
PublikacjaW pracy bada się wyboczenie giętne i zachowanie pokrytyczne ściskanego osiowo pręta z nieliniową sprężystą podporą w środku rozpiętości przęsła. Rozwiązanie problemu wyznaczono za pomocą metody małego parametru. Podano przykład numeryczny wyboczenia i zachowania pokrytycznego swobodnie podpartego pręta z nieliniową sprężytą podporą w środku rozpiętości. Wykazano istotny wpływ nieliniowości podpory na zachowanie pokrytyczne pręta.
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Displacement measurements during load testing of railway arch bridge
PublikacjaThe paper discusses issues concerning load tests carried out on a twin-track, arch railway bridge over the Martwa Wisla river in Gdansk. Currently, it is the bridge with the longest span in its class in Poland. The load-bearing structure consists of three no-hinge arches and an orthotropic deck suspended from them. The studies of the structure assumed the performing of static and dynamic tests. The paper presents the method for...
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Load Testing of GFRP Composite U-Shape Footbridge
PublikacjaThe paper presents the scope of load tests carried out on an innovative shell composite footbridge. The tested footbridge was manufactured in one production cycle and has no components made from materials other than GFRP laminates and PET foam. The load tests, performed on a 14-m long structure, were the final stage of a research program in the Fobridge project carried out in cooperation with: Gdańsk University of Technology (leader),...
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High load capacity spur gears with conchoidal path of contact
PublikacjaThe present study is devoted to investigation of spur gears with a conchoidal path of contact and a convex-convex contact between teeth. The load capacity and energy efficiency were evaluated using both theoretical and experimental approaches. The theoretical analysis showed that the conchoidal gear pairs are 5–21% stronger in terms of contact stress and have similar energy efficiency as compared to the involute gear pairs of the...
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Heuristic scheduling algorithms for uniform load of computer system
PublikacjaW pracy zaprezentowano opracowany heurystyczny algorytm szeregowania zadań UNILO (ang. UNIform LOad - jednakowe obciążenie), umożliwiający redukcję całkowitego zapotrzebowania na moc obliczeniową systemu komputerowego bez pogarszania jego wydajności. Algorytm ten realizuje takie przydzielenie zadań obliczeniowych do poszczególnych jednostek (procesorów), aby zapewnić ich jednakowe obciążenie. Opracowany algorytm został zweryfikowany...
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INFLUENCE OF LOAD AND INFLATION PRESSURE ON THE TYRE ROLLING RESISTANCE
PublikacjaTyre load and inflation pressure are important factors controlling rolling resistance of road vehicles. The article presents results obtained in the Technical University of Gdańsk during laboratory and road measurements of different car tyres rolling on different pavements. The knowledge of rolling resistance characteristics is important for modelling car dynamics as well as fuel consumption. It is also necessary to establish proper...
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Knowledge Management Critical Success Factors and the Innovativeness of KIBS Companies
PublikacjaThe purpose of this paper is to examine the influence of two critical success factors for knowledge management (i.e. leadership and support by the management, motivational practices) on the innovativeness of knowledge-intensive business service (KIBS) companies in the SMEs sector. A sample of 400 companies (KIBS SMEs) located in the Pomeranian District in Poland was selected. The questionnaire was designed to measure knowledge...
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The Influence of External Load on the Performance of Microbial Fuel Cells
PublikacjaIn this work, the effect of the external load on the current and power generation, as well as on the pollutant removal by microbial fuel cells (MFCs), has been studied by step-wise modifying the external load. The load changes included a direct scan, in which the external resistance was increased from 120 Ω to 3300 Ω, and a subsequent reverse scan, in which the external resistance was decreased back to 120 Ω. The reduction in the...
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Edgewise Compressive Behavior of Composite Structural Insulated Panels with Magnesium Oxide Board Facings
PublikacjaEdgewise compression response of a composite structural insulated panel (CSIP) with magnesium oxide board facings was investigated. The discussed CSIP is a novel multifunctional sandwich panel introduced to the housing industry as a part of the wall, floor, and roof assemblies. The study aims to propose a computational tool for reliable prediction of failure modes of CSIPs subjected to concentric and eccentric axial loads. An advanced...
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On the application of magnetoelastic properties measureme nts for plastic level determination in martensitic steels
PublikacjaThe change in the dislocation density, induced by plastic deformation, influences strongly the magnetic domain structure inside the material. Being so, classic parameters, like the coercivity or magnetic permeability, can be a good measure of the deformation level, yet their reliable determination in a non-destructive way in industrial environment is problematic. The magnetoacoustic emission (MAE) which results from the non-180...
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Biocompatibility and Bioactivity of Load-Bearing Metallic Implants
PublikacjaThe main objective of here presented research is to develop the titanium (Ti) alloy base composite materials possessing better biocompatibility, longer lifetime and bioactivity behaviour for load-bearing implants, e.g. hip joint and knee joint endoprosthesis. The development of such materials is performed through: modeling the material behaviour in biological environment in long time and developing of new procedures for such evaluation;...
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The effect of a belt position in the spindle driving system on critical rotational speeds
PublikacjaThe aim of this paper was to examine how the belt pulley position affects critical rotational speeds of the modernized spindle of the sliding table saw Fx3. Methodology of determination of critical rotational speeds of the spindle in a function of the spindle design features and its driving system is presented. Spindles in these kind of machine tools are mainly driven with V-belts, and the pulleys on the spindles might be positioned:...
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Integrated monitoring, control and security of Critical Infrastructure Systems
PublikacjaModern societies have reached a point where everyday life relies heavily on desired operation of critical infrastructures, in spite of accidental failures and/or deliberate attacks. The issue of desired performance operation of CIS at high security level receives considerable attention worldwide. The pioneering generic methodologies and methods are presented in the paper project for designing systems capable of achieving these...
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Static load test on concrete pile – instrumentation and results interpretation
PublikacjaFor some time (since 8-10 years in Poland) a special static load tests on instrumented piles are carried out. Such studies are usually of a scientific nature and provide detailed quantitative data on the load transfer into the ground and characteristics of particular soil layers interaction with a pile shaft and pile base. Deep knowledge about the pile-subsoil interaction can be applied for a various design purposes, e.g. numerical...
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Load testing of a suspended footbridge in Radom (Poland)
PublikacjaThe footbridge in Radom is a suspended bridge of an interesting architectural form. The structure was de-signed for 4 kN/m2 of crowd loading. Dynamic calculations were not included in the design. The structure’s acceptance tests took place on the 14th of October 2016. The behaviour of the footbridge in static testing met the expectations. Unfortunately, as a result of dynamic tests, dangerous behaviour of the footbridge was revealed....
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Experimental Study of Dapped-End Beams Subjected to Inclined Load
PublikacjaThis paper presents the results of an experimental investigation of the reinforced concrete (RC) dapped-end beams loaded with inclined forces, compared to identical ones loaded with vertical forces only. Such a load may occur in, for example, Gerber's joints or in dapped-end beams supported on corbels, where the vertical gravitation force is additionally completed with horizontal forces caused by temperature differences, shrinking,...
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Critical Case Stochastic Phylogenetic Tree Model via the Laplace Transform
PublikacjaBirth–and–death models are now a common mathematical tool to describe branching patterns observed in real–world phylogenetic trees. Liggett and Schinazi (2009) is one such example. The authors propose a simple birth–and–death model that is compatible with phylogenetic trees of both influenza and HIV, depending on the birth rate parameter. An interesting special case of this model is the critical case where the birth rate equals the...
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The effect of nonlinear restraint on torsional buckling and post-buckling behaviour of a thin-walled column
PublikacjaW pracy rozważa się wyboczenie skrętne i zachowanie pokrytyczne osiowo ściskanego swobodnie podpartego pręta cienkosciennego o przekroju otwartym ze sprężytą nieliniową podporą w środku rozpietości. Rozwiązanie problemu wyznaczono za pomocą metody małego parametru. W przykładzie numerycznym wyznaczono siłę krytyczną i ścieżkę początkowego zachowania pokrytycznego dwuteowego pręta z podporą sprężystą o charakterystyce składającej...
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Discussion - Experimental study of dapped–end beams subjected to inclined load
PublikacjaDiscussion - Experimental study of dapped–end beams subjected to inclined load
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Consideration of dynamic loads in the determination of axle load spectra for pavement design
PublikacjaAxle load spectra constitute a crucial part of the data for pavement design and pavement distress analysis. Typically, axle load spectra represent static load from vehicles and do not include dynamic loads generated by vehicles in motion. While dynamic loads can significantly contribute to faster pavement distress, this fact is mostly omitted in pavement design methods. The paper presents a methodology for consideration of dynamic...
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Distortional buckling of thin-walled columns of closed quadratic cross-section
PublikacjaThe elastic stability of axially compressed column related to the cross-section distortion is investigated. Two kinds of closed quadratic cross-sections are taken into consideration with internal walls and without it. The governing differential equation is derived with aid of the principle of stationary total potential energy. The critical loads for the simply supported columns are found in an analytical form and compared with...
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Modeling the Influence of Salts on the Critical Micelle Concentration of Ionic Surfactants
PublikacjaWe show for the first time that a phenomenological, augmented volume-based thermodynamics (aVBT) model is capable to predict the critical micelle concentrations of ionic surfactants, including ionic liquids, with added salts. The model also adjusts for the type of salt added by including its molecular volume, which might form a connection to the Hofmeister effect. The other physico-chemically relevant quantities included in the...
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Evaluating Security and Resilience of Critical Networked Infrastructures after Stuxnet
PublikacjaThe chapter presents the current configuration of the simulation environment for the evaluations of the security and resilience of critical networked infrastructures, which enables simulations of Stuxnet-like attacks. The configuration includes new features added to the MAlSim - Mobile Agent Malware Simulator after the advent of Stuxnet in reference to the experiments aiming at the security evaluation of a power plant which we...
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Approach to security assessment of critical infrastructures' information systems
PublikacjaThis study presents an approach to the security assessment of the information systems of critical infrastructures. The approach is based on the faithful reconstruction of the evaluated information system in a computer security laboratory followed by simulations of possible threats against the system. The evidence collected during the experiments, stored and organised using a proprietary system InSAW, may later be used for the creation...
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Integrated safety and security analysis of hazardous plants and systems of critical infrastructure
PublikacjaThis article addresses an integrated safety and security analysis approach of hazardous industrial plants and systems of critical infrastructure. Nowadays due to new hazards that emerge there are opinions among experts that these issues require an integrated approach in life cycle, from the design concept, through the design and operation of the plant, to its decommissioning. It is proposed to start from an interesting methodology...
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Regulatory approach to competition law in the practice of the Polish Competition Authority – critical assessment
PublikacjaThe text provides a critical analysis of the Polish practice of using competition law provisions as regulation provisions
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The use of GFRP tubes as load-bearing jackets in concrete-composite columns
PublikacjaThe paper presents the fields of applications of polymer composites in building structures. The use of composite glass fibre tubes is discussed in more detail. The laboratory methods used to test the mechanical properties of these pipes are presented. An original research program is presented, including six concrete-filled glass fibre tubes. The cylinders and columns made in this way were tested for their axial load capacity. Conclusions...
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Integrated approach for functional safety and cyber security management in maritime critical infrastructures
PublikacjaThe work is devoted important issues of the management in maritime critical infrastructure of functional safety analysis, in particular the safety integrity level (SIL) verification of safety functions to be implemented within the distributed control and protection systems with regard to cyber security aspects. A method based on quantitative and qualitative information is proposed for the SIL (IEC 61508, 61511) verification with...
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Ice Load Characteristics on Floating Photovoltaic Platform
PublikacjaNowadays, based upon human needs and preferring perpetual types of energy, photovoltaic system (PV) is a suitable alternative and more frequently used in northern countries, which are recently more attracted by solar power. The new floating type of the structure is installed in the water bodies instead of land. One of the main elements in floating photovoltaic structures is the forces imposed on the panels. In the northern regions,...
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Load path sensitivity and multiaxial fatigue life prediction of metals under non-proportional loadings
PublikacjaEngineering components often operate under complex loadings, in which the variable amplitude multiaxial stresses are raised by geometric discontinuities including holes, grooves, fillets and shoulders, etc. Besides, the non-proportional loading will lead to the rotation of maximum principal stress/strain and additional fatigue damage of structural elements in service. Consequently, the multiaxial and non-proportional loading have...
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Investigation of Weigh-in-Motion Measurement Accuracy on the Basis of Steering Axle Load Spectra
PublikacjaWeigh-in-motion systems are installed in pavements or on bridges to identify and reduce the number of overloaded vehicles and minimise their adverse eect on road infrastructure. Moreover, the collected trac data are used to obtain axle load characteristics, which are very useful in road infrastructure design. Practical application of data from weigh-in-motion has become more common recently, which calls for adequate attention to...
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Static Load Test on Instrumented Pile – Field Data and Numerical Simulations
PublikacjaFor some time (since 8-10 years in Poland) a special static load tests on instrumented piles are carried out. Such studies are usually of a scientific nature and provide detailed quantitative data on the load transfer into the ground and characteristics of particular soil layers interaction with a pile shaft and pile base. Deep knowledge about the pile-subsoil interaction can be applied for a various design purposes, e.g. numerical...
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Method of selecting programming practices for the safety-critical software development projects
PublikacjaIn recent years a plan-driven approach traditionally used in safety-critical software development has been put to a test by rapidly changing technologies, more diverse group of clients and volatile market requirements. The need to deliver good quality systems, faster and at lower cost in comparison to competitors encouraged companies to look for more efficient solutions. Agile methodologies are known to successfully address these...
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Current issues of functional safety and cybersecurity analysis of the industrial and critical infrastructures
PublikacjaThis article addresses some functional safety assessment procedures with cybersecurity aspects in critical industrial installations with regard to the functional safety requirements specified in standards IEC 61508 and IEC 61511. The functional safety management includes hazard identification, risk analysis and assessment, specification of overall safety requirements and definition of safety functions. Based on the risk assessment...
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Study on the accuracy of axle load spectra used for pavement design
PublikacjaWeigh-in-Motion (WIM) systems are used in order to reduce the number of overloaded vehicles. Data collected from WIM provide characteristics of vehicle axle loads that are crucial for pavement design as well as for the development of pavement distress prediction models. The inaccuracy of WIM data lead to erroneous estimation of traffic loads and in consequence inaccurate prediction of pavement distress process. The objective of...
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Managing the security vulnerabilities of critical systems and hazardous plants
PublikacjaRozdział poświęcono aktualnym problemom zarządzania ochroną obiektów podwyższonego ryzyka jako ważnych systemów infrastruktury krytycznej. Zarządzanie odpornością na ataki takich obiektów jest oparte na ocenach ryzyka. Podkreśla się, że występują ważne instalacje i systemy wymagające specjalnej uwagi i zabezpieczeń, szczególnie systemy kontroli dostępu do sterowni i urządzeń komunikacji. Opisuje się przykładowe technologie ochrony....
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Introducing agile practices into development processes of safety critical software
PublikacjaIn this paper we present AgileSafe - a method which supports introduction of agile practices into safety-critical software development processes. To represent safety assurance constraints resulting from the regulatory context, AgileSafe uses assurance case patterns. The knowledge base of AgileSafe helps the user to select the agile practices relevant for the considered software development project. The corresponding assurance case...
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Application of probabilistic tools to extend load test design of bridges prior to opening
PublikacjaLoad tests of bridges are widely performed in a large number of countries. Deterministic comparison of measurement results to the theoretical, FEM (finite element method)-based outcomes with possible further calibration is mostly applied. Sometimes, the data collected in the tests are also used to calibrate the reliability factors of bridge structures or their components. This work proposes to complement the stage of the load test...
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Experimental study on steel columns subjected to impact load under earthquake conditions
PublikacjaEarthquakes affecting urbanized regions cause exceptional loads to load bearing structural elements such as columns. Such a boost in the load conditions can lead to severe damages which, in a worst case scenario, can lead to a total collapse of a building. This boost is caused by the horizontal ground movement generating a rise in the internal forces due to considerable large displacement between the top and bottom support of columns....
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Redesign of the Research Platform for Monitoring, Control and Security of Critical Infrastructure Systems
PublikacjaCritical Infrastructure Systems (CISs) play a key role in modern societies. Their sustainable operation depends heavily on the performance of dedicated structures and algorithms targeting monitoring, control and security aspects. In previous work a Research Platform (RP) for the design and simulation of such systems was presented. This works updates the information on the RP through the description of major hardware and software...
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AgileSafe – a method of introducing agile practices into safety-critical software development processes
PublikacjaThis article introduces AgileSafe, a new method of incorporating agile practices into critical software development while still maintaining compliance with the software assurance requirements imposed by the application domain. We present the description of the method covering the process of its application and the input and output artefacts.
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Algorithms and Tools for Intelligent Control of Critical Infrastructure Systems
PublikacjaCritical Infrastructure Systems (CIS) are spatially distributed and of a network structure. The dynamics are nonlinear, uncertain and with several time scales. There is a variety of different objectives to be reliably met under a wide range of operational conditions. The operational conditions are influenced by the disturbance inputs, operating ranges of the CIS, faults in the sensors and actuators and abnormalities occurring in...
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Critical Success Factors for Knowledge Management in SMEs in the KIBS Sector
PublikacjaThe purpose of this paper is to examine knowledge management practices and critical success factors (CSFs) for their introduction in small and medium-sized enterprises (SMEs) in the knowledge-intensive business services (KIBS) sector. Methodology: The paper is based on the results of an exploratory qualitative survey involving owners and managers of small and medium-sized companies operating in the KIBS sector. In the survey, eight...
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Critical perspectives on media architecture
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Assessment of risks introduced to safety critical software by agile practices - a software engineer's perspective
PublikacjaIn this article we investigate the problem of applying agile practices into safety-critical projects.The goal of our research is to investigate potential benefits from introducing agile practicesinto safety-critical environment and to present a solution providing for balancing agileapproach with more disciplined assurance techniques, bringing the best of the two worlds together.In the article we present the supporting ideas such...
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Polysaccharide-based Nanocomposites for Biomedical Applications: A Critical Review
PublikacjaPolysaccharides (PSA) are taking specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties is known as the main drawback of PSA, which highlights need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use have not been reviewed. Herein we critically reviewed application...
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The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses
PublikacjaThe stress state in deformed solids has a significant impact on the attenuation of an ultrasonic wave propagating through the medium. Measuring a signal with certain attenuation characteristics can therefore provide useful diagnostic information about the stress state in the structure. In this work, basic principles behind a novel attenuation-based diagnostic framework are introduced. An experimental study on steel bars under three-point...
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Service-based Resilience via Shared Protection in Mission-critical Embedded Networks
PublikacjaMission-critical networks, which for example can be found in autonomous cars and avionics, are complex systems with a multitude of interconnected embedded nodes and various service demands. Their resilience against failures and attacks is a crucial property and has to be already considered in their design phase. In this paper, we introduce a novel approach for optimal joint service allocation and routing, leveraging virtualized...
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Torsional buckling paradox - extended studies.
PublikacjaAnalizowano wyboczenie skrętne pręta cienkościennego o dwuteowym przekroju poprzecznym ze zmienną szerokością półek. Wykazano, że siła krytyczna wyboczenia skrętnego może przekraczać granice wyznaczone przez siły odpowiadające prętom o stałych ekstremalnych szerokościach półek. Ten paradoksalny wynik uzyskano w ramach teorii prętów cienkościennych o przekroju nieodkształcalnym. Przeanalizowano siłę krytyczną wyboczenia skrętnego...
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On the plastic buckling of curved carbon nanotubes
PublikacjaThis research, for the first time, predicts theoretically static stability response of a curved carbon nanotube (CCNT) under an elastoplastic behavior with several boundary conditions. The CCNT is exposed to axial compressive loads. The equilibrium equations are extracted regarding the Euler–Bernoulli displacement field by means of the principle of minimizing total potential energy. The elastoplastic stress-strain is concerned...
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Load Tests of the Movable Footbridge Over the Port Canal in Ustka
PublikacjaThe paper presents the acceptance tests carried out on the open footbridge over the port canal in the Port of Ustka. The steel footbridge construction is created by a single pylon to which a movable truss span is suspended with a theoretical span of 52.3 m. The studies about load test of the object included static and dynamic extortion and measurements. In static tests the ballast was of pallets with concrete blocks. Dynamic studies...
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A method of the UMTS-FDD network design based on universal load characteristics
PublikacjaIn the paper an original method of the UMTS radio network design was presented. The method is based on simple way of capacity-coverage trade-off estimation for WCDMA/FDD radio interface. This trade-off is estimated by using universal load characteristics and normalized coverage characteristics. The characteristics are useful for any propagation environment as well as for any service performance requirements. The practical applications...
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Pedestrian bridge. Load and response
PublikacjaW pracy zdefiniowano dynamiczny model obciążenia pieszym w zależności od jego masy, rytmu chodu oraz drgań mostu. Zdefiniowana funkcja obciążenia zaimplementowana do komercyjnego programu MES, pozwala na symulacje dynamicznej odpowiedzi konstrukcji na zadane obciążenie. Przedstawiono dwa przykłady modelu teoretycznego w porównaniu z wynikami badań.