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Search results for: built environment
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High Efficiency Dual-Active-Bridge Converter with Triple-Phase-Shift Control for Battery Charger of Electric Vehicles
PublicationAn optimal modulation scheme with triple-phase-shift (TPS) control could increase the efficiency in the entire load range for a dual-active-bridge (DAB) converter under wide output voltage range conditions. Therefore, this study proposes a convergent approach to TPS mode selection, coupled with an optimal modulation scheme, ensuring the circuit’s efficiency over the entire range in the realm of a high-power and high-efficiency...
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Effect of crystallinity on structural, thermal, and in vitro dissolution properties of Na2O-CaO-Nb2O5/MgO-P2O5 glass-ceramics
PublicationThe impact of the crystallinity on structural, thermal, and in vitro dissolution properties were examined for Na2O- CaO-Nb2O5/MgO-P2O5 glasses/glass-ceramics. Glass-ceramics were synthesized via a spontaneous crystallization process. The Nb content in the materials increased with melting temperature, furthermore, the crystallinity is proportional to the Nb content. The presence of crystalline niobates and phosphates is confirmed...
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Performance Comparison of a 650 V GaN SSFET and CoolMOS
PublicationThe new technology of wide band gap semiconductors is said to outperform up-to-date silicon devices. High voltage Gallium Nitride (GaN) transistors, now emerging in the market, have even three times shorter switching times and even four times smaller energy losses compared to the best in-class Si devices. In this paper the performance of a 650 V GaN SSFET is evaluated and compared with the newest silicon family of CoolMOS™ technology....
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The low coherence Fabry-Pérot interferometer with diamond and ZnO layers
PublicationThe authors present a fiber-optic Fabry-Pérot interferometer built with the application of diamond and zinc oxide (ZnO) thin layers. Thin ZnO films were deposited on the tip of a standard telecommunication single-mode optical fiber (SMF- 28) while the diamond layer was grown on the plate of silicon substrate. Investigated ZnO layers were fabricated by atomic layer deposition (ALD) and the diamond films were deposited using Microwave...
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On the Limiting Distribution of Lempel-Ziv’78 Redundancy for Memoryless Sources
PublicationWe study the Lempel-Ziv'78 algorithm and show that its (normalized) redundancy rate tends to a Gaussian distribution for memoryless sources. We accomplish it by extending findings from our 1995 paper, in particular, by presenting a new simplified proof of the central limit theorem (CLT) for the number of phrases in the LZ'78 algorithm. We first analyze the asymptotic behavior of the total path length in the associated digital search...
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ROAD SAFETY WITHIN THE "INTEGRATED SYSTEM OF TRANSPORT SAFETY"
PublicationThe concept of the “Integrated System of Transport Safety” in Poland is a novel solution, built upon the best practices available from only a handful of countries in the world. In the last few decades, the extent of applying integrated transport safety systems to improve transport safety systems has varied; nevertheless, studying the experience of the safest countries in the world we can say that enormous progress has been achieved...
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Improvement of Task Management with Process Models in Small and Medium Software Companies
PublicationSmall and medium software companies exhibit many special features that give reason for a dedicated approach to process improvement. They often cannot afford implementing maturity models or quality standards both in terms of time and money. Instead, they expect simpler solutions that can allow to run projects in more systematic and repeatable way, increase quality and knowledge management. In this paper, we present a method focused...
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Development of banking sectors in Kosovo and Montenegro in the years 2000 - 2010
PublicationThe article presents main aspects of development of banking markets in two Balkan countries - Kosovo and Montenegro. Both of them are charaterised by similar recent history, both in political and economical fields. Their financial sectors have had to be built almost from scretch. The author describes stages of development of competition in the banking sectors, using the following ratios: performace, structure, liquidity. The data...
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Laser reflectance interferometry system with a 405 nm laser diode for in-situ measurement of CVD diamond thickness
PublicationIn situ monitoring of the thickness of thin diamond films during technological processes is important because it allows better control of deposition time and deeper understanding of deposition kinetics. One of the widely used techniques is laser reflectance interferometry (LRI) which enables non-contact measurement during CVD deposition. The authors have built a novel LRI system with a 405 nm laser diode which achieves better...
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OPERATIONAL PROBLEMS OF CONSTRUCTED WETLAND FOR LANDFILL LEACHATE TREATMENT: CASE STUDY
PublicationThe present paper discusses the quality fluctuations of leachate from municipal landfill in Gdansk (Poland) over the last 5 years and the evaluation of a wetland system designed for treatment of the leachate. The research has been conducted during a 5-year period. The constructed wetland for leachate treatment was built in 2001; it consists of 2 horizontal subsurface flow reed beds, working in parallel. In the period 2005–2006...
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Burnout Investigation of Small Diameter Tubes Immersed in Nanofluids
PublicationThis paper deals with research into pool boiling critical heat flux (CHF) of water–Al2O3, water–TiO2 and water–Cu nanofluids on horizontal stainless steel tubes. The experiments were conducted under atmospheric pressure. Nanoparticles were tested at concentrations of 0.001%, 0.01%, 0.1% and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. Although dispersants were not used to...
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Portico Farmhouses of the Vistula Delta: Architecture, Current State and Finite Element Modelling of Timber Roof Truss under Material and Cross-section Uncertainty
PublicationThe article focuses on the oldest surviving I-type portico houses located in the Vistula Delta, which were built in the 17th and 18th centuries. The study describes the houses’ origins, structure, details of roof structures and technical condition, and it also includes numerical modelling of a roof truss and its mechanical analysis. Numerical models of the roof trusses are defined and analysed by means of the finite element method....
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Dispersive Delay Structures With Asymmetric Arbitrary Group-Delay Response Using Coupled-Resonator Networks With Frequency-Variant Couplings
PublicationThis article reports the design of coupled-resonatorbased microwave dispersive delay structures (DDSs) with arbitrary asymmetric-type group delay response. The design process exploits a coupling matrix representation of the DDS circuit as a network of resonators with frequency-variant couplings (FVCs). The group delay response is shaped using complex transmission zeros (TZs) created by dispersive cross-couplings. We also present an...
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Low cost microwave X-band generator
PublicationA low cost microwave X-band generator for educational purposes was designed and built. Its simple construction and user's interface makes it suitable for a student laboratory.The generator is based on a single frequency conversion concept. It uses a digitally tunable PLL chip for intermediate frequency generation and an active frequency multiplier for frequency conversion. The generator covers 9,7 - 11 GHz part of the X frequency...
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Supporting compliance with safety standards by trust case templates
PublicationStandard Compliance (SC) Framework presented in this paper encompasses methods and tools which provide support for application of standards. The framework is based on trust case methodology. A trust case is a data structure which represents a justification that an object (a system, an infrastructure, an organization) exhibits certain properties. It contains an argument and related evidence which support claimed properties. A trust...
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Playback Attack Detection: The Search for the Ultimate Set of Antispoof Features
PublicationAutomatic speaker verification systems are vulnerable to several kinds of spoofing attacks. Some of them can be quite simple – for example, the playback of an eavesdropped recording does not require any specialized equipment nor knowledge, but still may pose a serious threat for a biometric identification module built into an e-banking application. In this paper we follow the recent approach and convert recordings to images, assuming...
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From structures to landscapes – towards re-conceptualization of the urban condition
PublicationThis paper presents an original approach towards the phenomena of re-naturalization of cities and indicates its possible consequences for the urban design and planning strategies. It focuses on the ongoing shift “from structures to landscapes” in understanding urban conditions. While modern architecture introduced geomet-ric compositions against the background of nature, early modern theories of architects and sociologists started...
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Spatial pattern of ASG-EUPOS sites
PublicationThe article presents the spatial pattern analysis of the ASG-EUPOS permanent GNSS stations in Poland. Using different methods and tools (nearest neighbour, Riplay’s K-function, morphology of Thiessen polygons) we proved that the station distribution model changes within scales. At short distances up to 65 km, which are typical lengths in the network, stations are irregularly dispersed. Increasing this distance to 130 km and over...
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Problems of analytical determination of journal bearing bush fatigue strength estimates
PublicationProblems connected with determination of stress distribution in sliding layer of thinwalled bearing bushes, investigated in bearing fatigue test rigs, have been presented. Using an example of plain bearings tested in the fatigue machine SMOK (built at the Gdask University of Technology) problems with obtaining a convergence of iterative procedure for determining the fatigue strength estimators of bearing alloy surface layer are...
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Enhancement of fiber-optic low-coherence Fabry-Pérot interferometer with ZnO ALD films
PublicationIn this paper investigation of the enhanced fiber-optic low coherence Fabry-Pérot interferometer with zinc oxide (ZnO) film deposited by atomic layer deposition (ALD) was presented. Model of the interferometer, which was constructed of single-mode optical fiber with applied ZnO ALD films, was built. The interferometer was also examined by means of experiment. Measurements were performed for both reflective and transmission modes,...
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Counting and tracking vehicles using acoustic vector sensors
PublicationA method is presented for counting vehicles and for determining their movement direction by means of acoustic vector sensor application. The assumptions of the method employing spatial distribution of sound intensity determined with the help of an integrated 3D intensity probe are discussed. The intensity probe developed by the authors was used for the experiments. The mode of operation of the algorithm is presented in conjunction...
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SiC-based T-type modules for multi-pulse inverter with coupled inductors
PublicationThe paper presents SiC-based three-level T-type modules designed for a high-performance 30kVA DC/AC inverter operating at high frequency 85 kHz with low THD of the output voltage. This inverter system consists of two integrated parts. The first part is active and contains three parallelconnected three-phase T-type modules built with fast-switching SiC power transistors. The second, passive part of the system is a set of inductors...
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Application of Bayesian Networks in risk diagnostics arising from the degree of urban regeneration area degradation
PublicationUrban regeneration as a complex project, generates many extremely specific threats affecting the increase of investment risk. Its unique nature causes that probability parameter, normally applied in the process of risk quantification, is extremely difficult to estimate. Due to lack of historical data urban regeneration related activities are therefore associated with uncertainty. According to the authors, a useful tool for resolving...
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Application of BN in Risk Diagnostics Arising from the Degree of Urban Regeneration Area Degradation
PublicationUrban regeneration as a complex project, generates many extremely specific threats affecting the increase of investment risk. Its unique nature causes that probability parameter, normally applied in the process of risk quantification, is extremely difficult to estimate. Due to lack of historical data urban regeneration related activities are therefore associated with uncertainty. According to the authors, a useful tool for resolving...
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On the current state of dovetail wall-corner joints in wooden Greek Catholic churches in Polish Subcarpathia with structural and sensitivity analyses
PublicationThis paper describes the current condition of some dovetail joints which form the wall corners of two Greek Catholic churches of wooden construction in Polish Subcarpathia. It also gives the historical background of the sacral architecture of that region. The two structures, which represent the same type of log corner joints are situated in Chotylub and Cewków. The buildings were examined e.g. for damage, wood moisture content,...
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Influence of sheet/purlin fasteners spacing on shear flexibility of the diaphragm
PublicationThe paper presents the influence of sheet/purlin fasteners location (in reference to trapezoidal profile cross section) on shear flexibility of the cladding acting as a diaphragm. Analytical procedures were presented and their limitations were discussed. Next, selected schemes of fasteners location, known from engineering practice, but not included in European codes and recommendations, were analysed numerically in order to observe...
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APPLICATION OF REDUNDANCY IN SHIP POWER PLANTS OF OFFSHORE VESSEL
PublicationPower and propulsion systems of offshore units must be of a very high level of reliability. The loss of ability to perform functions of their components causes generally to very high economic losses, which may be increased by unused the weather window resulting to postponing the planned offshore operations. To ensure carrying out so expensive offshore operations in the most reliable way, various types of redundancies are built-in...
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Highlighting interlanguage phoneme differences based on similarity matrices and convolutional neural network
PublicationThe goal of this research is to find a way of highlighting the acoustic differences between consonant phonemes of the Polish and Lithuanian languages. For this purpose, similarity matrices are employed based on speech acoustic parameters combined with a convolutional neural network (CNN). In the first experiment, we compare the effectiveness of the similarity matrices applied to discerning acoustic differences between consonant...
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Networking and Familiness as Factors Stimulating the Early Internationalization of High-Tech Firms
PublicationThe problem of the role and importance of time in the process of firm’s internationalization belongs to the mainstream of international business research, as is the problem of the key role of high-tech firms operating across borders. The main goal of the paper is to understand how selected factors determine early internationalization of high-tech firms in Poland as an emerging market. The theoretical framework of the article is...
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The Dynamics of Trade Relations between Ukraine and Romania: Modelling and Forecasting
PublicationThe article examines the monthly dynamics of exports, imports and balance of trade between Ukraine and Romania in the period from 2005 to 2021. Time series from 2015 to 2021 were used for modelling and forecasting (since the date the European Union–Ukraine Association Agreement took effect). Adequate models of the dynamics series of the Box-Jenkins methodology were built: additive models with seasonal component ARIMA (Autoregressive...
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The Idea of a Student Research Project as a Method of Preparing a Student for Professional and Scientific Work
PublicationIn the paper we present the idea and implementation of a student research project course within the master’s program at the Faculty of Electronics, Telecommunications and Informatics, Gdansk Tech. It aims at preparing students for performing research and scientific tasks in future professional work. We outline the evolution from group projects into research project and the current deployment of both at bachelor’s and master’s levels...
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Revitalizing the Sacral Complex of the Parish of the Sacred Heart of Jesus in Gdynia: A Comprehensive Restoration Project in Alignment with Monument Conservator's Guidelines and Technical Prerequisites
PublicationReligiouscomplexes, due to their monumental character, belong to the group of facilities in which carrying out renovation works is difficult. Very often, construction works carried out as part of planned renovation work include not only modernization but also repair works, includingthose related to the reinforcement of structural elements. Renovation work in sacral buildings is particularly difficult when they...
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PV installations and the safety of residential buildings
PublicationThe dynamic development of the photovoltaic industry entails threats that have a direct impact on the safety of residential buildings. Appropriate design of a PV installation can be a challenge due to the multifaceted nature of this issue. The designer should take into account issues related to the selection of electrical parameters of the installation, adapting lightning and surge protection in accordance...
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Mechatronic design o strongly nonlinear systems on a basis of three wheeled mobile platform
PublicationRemarkable grow in demand both of mobile platform operability performance and reduction of project leading time development encourage to apply modern algorithms and reliable engineering tools for the design process. The paper discusses the mechatronic design applied for the surveillance system based on the energy performance index algorithm. The exploited mechatronic techniques i.e. virtual prototyping, Hardware-In-the-Loop Simulation...
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Theoretical and Architectural Framework for Contextual Knowledge Bases
PublicationThe paper presents the approach aimed at building modularized knowledge bases in a systematic, context-aware way. The paper focuses on logical modeling of such knowledge bases, including an underlying SIM metamodel. The architecture of a comprehensive set of tools for knowledge-base systems engineering is presented. The tools enable an engineer to design, create and edit a knowledge base schema according to a novel context approach...
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Five-phase induction motor drive with sine-wave filter
PublicationThe paper presents closed loop ac drive with 5 phase induction motor operating with voltage source inverter and sine wave filter. The motor supply voltages and currents have sinusoidal shape. For well known adjustable electric drives the field oriented control method with flux and speed co ntrol can be applied. In the presence of output filter both control and estimation algorithms should be modified due to sine wave filter installation....
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Towards Healthcare Cloud Computing
PublicationIn this paper we present construction of a software platform for supporting medical research teams, in the area of impedance cardiography, called IPMed. Using the platform, research tasks will be performed by the teams through computer-supported cooperative work. The platform enables secure medical data storing, access to the data for research group members, cooperative analysis of medical data and provide analysis supporting tools...
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Benchmarking the Digital Government Value Chain
PublicationDigital Government (DG) benchmarking is an academically vivid topic and, equally important, a tool with the potential to provide valuable insights to policymakers and public managers responsible for digital policies at the level of countries and international bodies. Alas, this potential remains largely untapped in the current DG benchmarking practice. In our study, we identify the reasons and propose a way of mitigating them....
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High-conducting Bi4V2-xFexO11-δ ceramics containing Fe2O3 nanocrystals: Structure and properties
PublicationThe topography, structure, thermal, magnetic, and electrical properties of Bi4V2-xFexO11-δ ceramics substituted with x = 0.5 and 0.7 Fe were studied. The microscope analysis showed the presence of iron-rich nanocrystals formed on the Bi-Fe-V-O grains. The X-ray diffraction studies confirmed that grains are built mostly of tetragonal Bi4V1.5Fe0.5O10.5 phase. Thermal properties analysis showed an order-disorder type γ ↔ γʹ phase...
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New RFID readers for scalable RFID system
PublicationRFID systems gives the opportunity to have wide access control integrated with the monitoring of people and goods flow. System's scalability is one of the most important features in such systems as they enable large scale deployments. The concept of the proposed reader's architecture employs new RFID transceivers and microcontrollers, security algorithms which gives very high functionality at low price. Special treatment of system's...
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Developing an Ontology from Set of Experience KnowledgeStructure
PublicationWhen referring to knowledge forms,collecting for all decision eventsin a knowledge-explicit way becomes a significant ask for any company. Set of experience knowledge structure can assis in accomplishing this purpose.However,after collecting,distributing and sharing that knowledge as adecisional DNA is even a more important advance.Distributing and sharing companies' decisional DNA through an efficient development of Ontologies...
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Application of the expanded clay aggregate in form of granular materials for water treatment
PublicationThe paper aimed to evaluate the efficiency of Filtralite MonoMulti compared to the conventional dual-media filter beds comprising silica sand layer covered with anthracite coal. Filtralite media are composed of processed (expanded), highly porous clay products characterized by relatively rough grain surfaces. In order to compare these different media filters in a reliable way, the pilot filter columns operated in parallel, under...
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Models of Structures in Didactics
PublicationThe final aim of teaching students subjects, such as structural mechanics, reinforced concrete, and steel structures is to teach them how structures work in a given building as well as to provide them with skills enabling them to calculate and design structures. The behavioral model of the structure, contrary to the architectural model, which focuses mainly on the external form of the building, shows workings from both the static...
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Technology Concept of TLP Platform Towing and Installation in Waters with Depth of 60 m
PublicationThe article is part of the design and research work conducted at the Gdansk University of Technology, Faculty of Ocean Engineering and Ship Technology, in cooperation with a number of other research centres, which concerns offshore wind farms planned to be built in the Polish zone of the Baltic sea in the next years. One of most difficult tasks in this project is building suitable foundations for each power unit consisting of a...
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Quantum Steering Inequality with Tolerance for Measurement-Setting Errors: Experimentally Feasible Signature of Unbounded Violation
Publicationuantum steering is a relatively simple test for proving that the values of quantum-mechanical measurement outcomes come into being only in the act of measurement. By exploiting quantum correlations, Alice can influence — steer — Bob ’ s physical system in a way that is impossible in classical mechanics, as shown by the violation of steering inequalities. Demonstrating this and similar quantum effects for systems of increasing size,...
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Original footbridge in Mikolajki, Poland
PublicationIn summer 2016, a new footbridge in the town of Mikołajki (Poland) was built, over a stream connecting two adjacent lakes – Talty and Mikołajki. Its modern construction, based on the shape of a DN ice-boat, makes it inique in Poland, and probably in the world as well. This novel and dynamic shape became a significant landmark associated not only with Mikołajki, but also with the whole region of Mazury, as well as with sailing...
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Agricultural products' storage control system
PublicationThe paper discusses the idea and the design of a remote control system for storage management of agricultural products which temperature may rise as the result of biological processes during the storage. An actual potatoes storehouse is discussed as an application for the proposed automation system. Because of existing buildings and infrastructure at the farm, wireless data transfer system has been proposed for communication between...
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Mechanical properties of polyester reinforced PVC coated fabric subjected to biaxial loading of creep type
PublicationThe goal of the current study is to analyze the basic mechanical properties of the architec-tural fabric VALMEX, which is a composite material built of reinforcing polyester thread families and both sides PVC coated. The material was firstly subjected to biaxial loading of creep type for about 48 hours. The stress levels of the creep loading in two main or-thogonal directions of the fabric (commonly called the warp and fill directions)...
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Smartphone application supporting independent movement of the blind
PublicationImproving comfort of life of blind people is a problem of great importance. Neither a white canenor a guide dog, although both very useful, can be considered as a tool for achieving fullindependence in everyday movement around the city. On the market there are some navigation toolsinspired by car navigation systems, but they have many flaws, ranging from positioninginaccuracies to high prices. The authors present their own solution...
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Assurance Case Patterns On-line Catalogue
PublicationAssurance case is an evidence-based argument demonstrating that a given property of a system (e.g. safety, security) is assured. Assurance cases are developed for high integrity systems, as in many industry domains such argu-ment is explicitly required by regulations. Despite the fact that each assurance case is unique, several reusable argument patterns have been identified and pub-lished. This paper reports work on development...