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Service time distribution influence on end-to-end call setup delay calculation in networks with Session Initiation Protocol
PublicationThe most important GoS parameter for networks with SIP protocol is end-to-end call setup delay. So far there were no coherent models allowing calculation of these parameters for networks with SIP protocol. Few models were developed but they are insufficient. In the paper we propose model which allows end-to-end call setup delay calculation for networks with SIP protocol. The model is using chain of M/G/1/K models and is applicable...
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Life tests of a rotary single-stage magnetic-fluid seal for shipbuilding applications
PublicationUse of the magnetic fluid seal technology in water is much more difficult technological problem in comparisonto gas or vacuum environment. Some seals constructed up to time been are designed as hybrid, two stagesealing structures with shields or mechanical seals used as protection measures to the magnetic fluid seal.Anyway, there is always problem with immediate contact between magnetic fluid and the environmentalliquid. In the...
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Additive Manufacturing as a Solution to Challenges Associated with Heat Pipe Production
PublicationThe aim of this review is to present the recent developments in heat pipe production, which respond to the current technical problems related to the wide implementation of this technology. A novel approach in HP manufacturing is to utilise hi-tech additive manufacturing techniques where the most complicated geometries are fabricated layer-by-layer directly from a digital file. This technology might be a solution to various challenges...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results
PublicationThe edge criteria for magnetic-fluid seals durability research are critical for the seal'stechnological usefulness. The magnetic fluid seal technology in water is much moredifficult technological problem in comparison to gas or vacuum environment. There isalways problem with immediate contact between magnetic fluid and the environmentaluninspected liquids. In the paper are presented ways of experiments definitions carried outwith...
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Noninvasive method for rotor fault diagnosis in inverter fed induction motor drive
PublicationThis article presents a proposal, simulation and experimental results of a noninvasive rotor fault diagnosis method for the inverter fed induction motor drive. Comparing to reported methods the proposed one does not require any load, rotor brake, slip, mechanical or electrical system physical modification e.g. machine disassembly and can be applied regardless the rotor speed measurement or estimation method.
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M2M communications system proposal for maritime applications
PublicationThis article describes the proposal to use the M2M communication to enhance the safety of people, ships and other marine infrastructure, in broadly defined marine systems. In addition, there are numerous examples of planned solutions to be implemented in the near future as well as new services. The proposal for M2M communication system architecture is described below. In addition, the use of the STRUGA system radio interface as...
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Volume optimization of high-speed surface-mounted permanent magnet synchronous motor based on sequential quadratic programming technique and analytical solution
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Canonical switched capacitor converters. Comments, complements, and refinements
PublicationSwitched Capacitor Converters (SCC) form useful blocks in low/medium power applications as they are suitable for integration, both as off-chip and on-chip IC realizations. However, the problem with SCC is that their voltage conversion ratio is topology-dependent. By changing the SC circuit configuration, we can gain control over voltage conversion but the available ratio remains of a discrete nature, i.e. it maps into a countable...
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The Lighting Designer and New Technologies: Lighting for Enhancing Business in Shops & Restaurants – The Do’s & Don’ts of Retail Lighting
PublicationThis paper will address issues of successful retail lighting schemes to make the audience familiar with the Do’s & Don’ts. It will also look into the details of designing lighting particularly for window displays, external shop signage and outdoor terraces of restaurants. A holistic approach to retail lighting will be presented with case studies of ‘good’ and ‘bad’ lighting solutions, mostly from Europe, to underline the impacts...
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Dobór parametrów silnika indukcyjnego dużej mocy
PublicationW artykule przedstawiono trzy typy statycznych modeli matematycznych silników klatkowych oraz metodę estymacji parametrów, przy wykorzystaniu algorytmów genetycznych. Korzystając z kryteriów: suma kwadratów, suma wartości bez-względnych oraz całkowego, oceniono przydatność badanych modeli. Opracowane modele matematyczne zostały wykorzystane przy doborze algorytmów sterownia sterów strumieniowych. Po-kazano metodykę doboru parametrów...
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Endoscopic image processing and analysis of pistons' service failures of marine diesel engines
PublicationThe paper deals with diagnostic issues concerning endoscopic examinations of working spaces within marine diesel engines. In the beginning, endoscopy apparatus being on laboratory equipment of the Department of Ship Power Plants of Gdansk University of Technology has been characterized. The endoscopy considerations have been focused on theoretical bases of a digital image processing and especially - on the "Shadow" measurement...
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Surface sediments pollution due to shipwreck s/s “Stuttgart”: a multidisciplinary approach
PublicationShipwrecks may pose a serious source of pollution for marine ecosystems. For this reason, it is of great importance to perform a marine ecosystem risk assessment due to plausible wreck presence. One of elements of such an assessment is determining the state of the environment in the vicinity of the wreck. In the work presented, the results of studies on surface sediments samples collected around the s/s Stuttgart ship sunk during...
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Wyznaczenie obciążeń na poszycie okrętu wywołanych uderzeniem fal i uderzeniem w lód i ich wpływ na bezpieczeństwo okrętu
PublicationThe main problem is the vessels rather accurate determination of the hydrodynamic loads so-called hydroelasticity outside . This can be done by theoretical analysis , computer simulation or by experiment. This gives the hydrodynamic pressure distribution on the walls of the ship's hull and also on the walls of marine vessels .The most dangerous are the impact of extreme storm waves , the impact of the wharf and the impact zone...
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Numerical and experimental study on effect of boundary conditions during testing of stiffened plates subjected to compressive loads
PublicationThis study analyses the effect of boundary conditions during testing on the structural behaviour stiffened plates with different thicknesses subjected to compressive loads. The goal of the compressive tests is to analyse the ultimate strength of a stiffened plate. During the test, relevant physical quantities are measured and investigated. The supporting structure's behaviour is investigated by analysing the force-displacements...
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The Matter of Decision-Making Control Over Operation Processes of Marine Power Plant Systems with the Use of their Models in the form of Semi-Markov Decision-Making Processes
PublicationThe article presents the possibility to control the real operation process of an arbitrary device installed in the marine power plant based on the four-state semi-Markov process, being the model of the process, which describes the transition process of operational states of the device and the transition process of its technical states. All these states are precisely defined for the ship main engine (SG). A hypothesis is proposed...
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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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Tester wydajności centralek IP PABX
PublicationW artykule przedstawiono koncepcję i sposób realizacji testera wydajności centralek IP PABX pracujących z protokołem SIP i RTP. Jako kryterium określania wydajności przyjęto spełnienie granicznych wartości wielkości opisujących GoS i QoS. Zaproponowano architekturę testera wydajności, jego podział na bloki funkcjonalne i ich opis. Omówiono sposób generacji strumieni SIP i RTP koniecznych do badania wydajności centralek IP PABX,...
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Analiza doświadczalna wpływu długości zakotwienia pręta na zachowanie przyczepności w teście pull-out
PublicationArtykuł prezentuje badania przyczepności przeprowadzone przy użyciu testu pull-out. Eksperymenty miały na celu ocenę wpływu długości zakotwienia na przyczepność w tym teście. Z przeprowadzonej analizy wynika, że długość styku pręt-beton znacząco wpływa na zachowanie przyczepności. Określa ona typ zniszczenia połączenia, wpływa na rozkład i wartość naprężeń w pręcie oraz rzutuje na przebieg krzywej przyczepność-poślizg, która jest...
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ZASTOSOWANIE MACIERZY PSEUDO ODWROTNEJ W METODACH ALOKACJI PĘDNIKÓW UKŁADU DYNAMICZNEGO POZYCJONOWANIA STATKU
PublicationUkłady kontroli alokacji pędników stanowią ważną część systemów dynamicznego pozycjonowania na statku. Określają one sygnały sterujące nastawami pędników, na podstawie uogólnionego wektora sił wzdłużnej, poprzecznej i momentu skręcającego, uzyskiwanych z prawa sterowania. W artykule przedstawiono wybrane algorytmy kontroli alokacji pędników, różniące się sposobem wyznaczania macierzy pseudo odwrotnej oraz algorytm bezpośredniej...
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Algorytmy wyodrębniania składowych symetrycznych sygnału pomiarowego napięcia w przypadku asymetrii sieci trójfazowej
PublicationW artykule zaprezentowano działanie wybranych algorytmów wykorzystywanych do wyodrębniania składowych symetrycznych z sygnałów pomiarowych napięcia lub prądu w przypadku wystąpienia asymetrii trójfazowej sieci elektroenergetycznej. Weryfikacji działania algorytmów dokonano na podstawie badań symulacyjnych i laboratoryjnych w układzie w którym jako odbiornik zastosowano stojan maszyny asynchronicznej pierścieniowej. Określono wpływ...
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Inkjet Printing of Lanthanide–Organic Frameworks for Anti-Counterfeiting Applications
PublicationPhotoluminescent lanthanide−organic frameworks (Ln-MOFs) were printed onto plastic and paper foils with a conventional inkjet printer. Ln-MOF inks were used to reproduce color images that can only be observed under UV light irradiation. This approach opens a new window for exploring Ln-MOF materials in technological applications, such as optical devices (e.g., lab-on-a-chip), as proof of authenticity for official documents.
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PRZEGLĄD KONSTRUKCJI WARSTWOWYCH
PublicationArtykuł przedstawia konstrukcje warstwowe typu SPS (Sandwich Plate System), SIP (Structural Insulated Panels) oraz hybrydowe (laminaty metalowo-włókniste FML) a także ich budowę, właściwości oraz wykorzystanie w różnych sektorach przemysłu.
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Z historii Stowarzyszenia Inżynierów Polskich w Kanadzie
PublicationPrzedstawiono pokrótce historię Stowarzyszenia Inżynierów Polskich w Kanadzie. Omówiono działalność stowarzyszenia, które obchodzi w roku 2021 80 lat istnienia. Wskazano niektóre związki SIP w Kanadzie z absolwentami Politechniki Gdańskiej.
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Nowoczesne układy przekształtników wielopoziomowych do zasilania statków z lądu
PublicationW artykule poruszono tematykę zasilania statków zacumowanych w porcie z lądowej sieci elektroenergetycznej poprzez wykorzystanie nowoczesnych konstrukcji przekształtników energoelektronicznych. W treści pracy zaprezentowano porównanie dwóch topologii wysokonapięciowych przekształtników wielopoziomowych. Porównano konstrukcje przekształtników z klasycznym transformatorem wielouzwojeniowym oraz z transformatorami wysokoczęstotliwościowymi.
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Low-Profile Interdigitated UHF RFID Tag Antenna for Metallic Objects
PublicationThis article presents a novel miniature interdigitated ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna that can be placed on metallic objects. The tag structure comprises two horizontal strip lines, each loaded with seven identical open stubs, and an integrated circuit (IC) chip connected directly to the feed lines in the middle of the structure. The perfect match to the IC chip’s impedance is realized...
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An Integrated Approach to an Assessment of Bottlenecks for Navigation on Riverine Waterways
PublicationWater transport, both sea and inland, is the cheapest, least invasive, and safest option for non-standard loads; hence, it is important to increase the percentage share of inland waterway transport on the rivers of Central and Eastern Europe. Transporting cargo is particularly difficult on shallow waterways because rivers overloaded with sediment determine the vertical parameters on inland waterways. A ship’s safe manoeuvrability...
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Collision Risk-Informed Weather Routing for Sailboats
PublicationSelected COLREG rules, good seamanship and sheer common sense indicate that it is in a sailboat's interest to follow collision-free routes without relying on large power-driven ships to give way. Until now, however, no method has integrated a sailboat's weather routing with collision risk monitoring and collision avoidance. Therefore, a new deterministic approach to combine the above features within one method is introduced here....
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Lithuania inland waterways and its prospects
PublicationInland waterways have some traditions in Lithuania and in neighbor Countries, but during last 50 years other modes of transport move out inland waterway transport from real economical activity. In the same time inland waterways is the main green and sustainable transport system. In this article are presented analysis situation, methodology for the ships optimal using in inland waterways, forecasting of the possible cargo and passenger...
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Nondestructive corrosion degradation assessment based on asymmetry of guided wave propagation field
PublicationThe article presents the results of numerical and experimental investigation of guided wave propagation in steel plates subjected to corrosion degradation. The development of novel procedures allowing for the assessment of the corrosion degradation level is crucial in the effective diagnostics of offshore and ship structures that are especially subjected to aggressive environments. The study’s main aim is to investigate the influence...
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Designate CTOD of Weld Metal of butt weld, No WOiO/II/108/2013
PublicationTypical (normative) testing of materials and/or welded joints do not answer on all questions about material or welded joint properties. In ship building and off-shore sectors, many strucures requires materials and joint with higher than typical fatigue resistance. Imact tests, which are carried out during welding technology qualification, gives answer about ductility, CTOD tests results about material or welded joint ability...
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Designate of CTOD for WM and HAZ, report no: WOiO/II/122/2014
PublicationTypical (normative) testing of materials and/or welded joints do not answer on all questions about material or welded joint properties. In ship building and off-shore sectors, many strucures requires materials and joint with higher than typical fatigue resistance. Imact tests, which are carried out during welding technology qualification, gives answer about ductility, CTOD tests results about material or welded joint ability to...
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Designate CTOD Heat Affected Zone of butt weld, Report No: WOiO/II/76/2013
PublicationTypical (normative) testing of materials and/or welded joints do not answer on all questions about material or welded joint properties. In ship building and off-shore sectors, many strucures requires materials and joint with higher than typical fatigue resistance. Imact tests, which are carried out during welding technology qualification, gives answer about ductility, CTOD tests results about material or welded joint ability...
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CTOD designation for WM and HAZ in butt joint made from S460 ML steel, Expertise No. WOiO/II/82/2015
PublicationTypical (normative) testing of materials and/or welded joints do not answer on all questions about material or welded joint properties. In ship building and off-shore sectors, many strucures requires materials and joint with higher than typical fatigue resistance. Imact tests, which are carried out during welding technology qualification, gives answer about ductility, CTOD tests results about material or welded joint ability to...
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ENERGY EFFICIENT SMALL INLAND PASSENGER SHUTTLE FERRY WITH HYBRID PROPULSION - CONCEPT DESIGN, CALCULATIONS AND MODEL TESTS
PublicationIn recent years, there has been a significant development in “green” and energy efficient propulsion systems, which fits into the general trend of environmentally friendly “green shipping”. The pursued goal is to construct a safe passenger ship that is low in energy demand and equipped with a highly energy efficient, emission-free propulsion system. The paper presents main problems encountered by designers of a small, hybrid-powered...
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Hydrodron — New Step for Professional Hydrography for Restricted Waters
PublicationHydrographic surveys in restricted areas are becoming increasingly important, but often impossible to carry out with conventional hydrographic vessels. Presumably in this case an employment of unmanned vehicles is the only reasonable solution. As restricted water areas include, among others: harbours, roadsteads, rivers or lakes. The HydroDron platform, due to its mobility, can operate in the above-mentioned areas. It is adapted...
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Validation Process for Computational Model of Full-Scale Segment for Design of Composite Footbridge
PublicationExperimental tests and numerical simulations of a full-scale segment of a foot and cycle bridge made of polymer composites are presented in the paper. The analysed structure is made of sandwich panels, which consist of glass fibre reinforced polymer (GFRP) multi-layered laminate faces and a PET foam (obtained from recycling) core. The dimensions of the segment cross-section are the same as for the target footbridge; however, span...
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Temperature effect on the emission spectra of narrow band Mn4+phosphors for application in LEDs
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Analyses of Shear Angle in Orthogonal Cutting of Pine Wood
PublicationThe determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The...
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Selected aspects of system design theory.
PublicationPrzedstawiono wybrane fragmenty z teorii i techniki projektowania złożonych systemów technicznych. Zwrócono szczególną uwagę na tworzenie schematów strukturalnych i funkcjonalnych systemów, a także występujących tam relacji między elementami takiego systemu. Opisano kolejne kroki postępowania dla doboru cech elementów systemu wg macierzy ich przewidywanych właściwości oraz przykłady podziału dla istniejących składników systemów...
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Theoretical study of thermofrictional oscillations due to negative friction-temperature characteristic
PublicationAnalytical study on oscillations of a body on a moving counterbody has been done by assuming imperfect frictional thermal contact and friction that decreases with contact temperature. It has been shown that stick-slip oscillation occurs due to decrease of friction coefficient when the body moves in the opposite direction to the counterbody. Dynamical characteristics, such as conditions for stable sliding and limit cycles, have...
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Thermal and technological aspects of double face grinding of Al2O3 ceramic materials
PublicationDouble face grinding with planetary kinematics is a process to manufacture workpieces with plan parallel functional surfaces, such as bearing rings or sealing shims. In order to increase the economic efficiency of this process, it has to be advanced permanently. The temperature in the contact zone of most grinding processes has a huge influence on the process efficiency and the workpiece qualities. In contrast to most grinding...
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A CNN based coronavirus disease prediction system for chest X-rays
PublicationCoronavirus disease (COVID-19) proliferated globally in early 2020, causing existential dread in the whole world. Radiography is crucial in the clinical staging and diagnosis of COVID-19 and offers high potential to improve healthcare plans for tackling the pandemic. However high variations in infection characteristics and low contrast between normal and infected regions pose great challenges in preparing radiological reports....
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Thermal analysis and experimental verification of permanent magnet synchronous motor by combining lumped-parameter thermal networks with analytical method
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AC Motor Voltage and Audible Noise Dataset
PublicationThe dataset titled AC motor voltage and audible noise waveforms in ship’s electrical drive systems with frequency converters contains the voltage and sound measurement results recorded in a marine frequency controlled AC drive system. The dataset is part of research focussing on the impact of the ship’s electrical drive systems with frequency converters on vibrations and the level of audible noise on ships. The dataset allows the...
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ENTERPRISE ACTIVITIES MODELING BY BPMN NOTATION
PublicationDepending on the process behavior, available know-how and organizational goals, different techniques and tools can be used for business process modeling. We concentrate on e-commerce, and try to find the best marketing strategy for the sales process improvement. In the paper we present the multilayer approach to define enterprise scenarios. This allows us to collect the suitable knowledge necessary for enterprise analysis and improvement....
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Push-to-talk als eine der ersten voip - applikationen in mobilfunknetzen
PublicationW pracy przedstawiono wybrane aspekty realizacji multimediów w sieciach komórkowych. Dokonano analizy protokołu SIP ze szczególnym uwzględnieniem pomiarów systemów rzeczywistych. Oceniono nową usługę PoC (Push-to-Talk over Cellular)- pierwszą aplikację typu VoIP realizowaną w sieciach komórkowych
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Efektywna metoda wyznaczania trasy statków żaglowych
PublicationZaproponowano metodę wyznaczania suboptymalnej trasy statków żaglowych poruszających się w ograniczonym akwenie morskim. Uwzględniono przy tym dynamikę tego środowiska w tym warunki pogodowe oraz charakterystyki prędkościowe statków żaglowych. Jako kryterium optymalizacji przyjęto czas żeglugi T oraz liczbę wykonanych manewrów ω. Zaprojektowano heurystyczny algorytm oraz odpowiednią aplikację wyznaczania trasy dla ustalonych punktów...
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Revisiting The Determination Of Cutting Power While Sawing Of Wood With Circular Saw Blades By Means Of Fracture Mechanics
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, cutting forces (power) could be considered from a point of view of modern fracture mechanics. Cutting forces may be employed to determine not only toughness...
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High resolution optical and acoustic remote sensing datasets of the Puck Lagoon
PublicationThe very shallow marine basin of Puck Lagoon in the southern Baltic Sea, on the Northern coast of Poland, hosts valuable benthic habitats and cultural heritage sites. These include, among others, protected Zostera marina meadows, one of the Baltic’s major medieval harbours, a ship graveyard, and likely other submerged features that are yet to be discovered. Prior to this project, no comprehensive high-resolution remote sensing...
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Analysis of Signalized Intersections in the Context of Pedestrian Traffic
PublicationGdynia is a city in the Pomeranian Voivod e ship of Poland with a population of about 250,000. It faces a growing motorization rate th at needs to be addressed. Car ownership in Gdynia now exceed s 500 vehicles per 1000 residents. Travel by public transport is decreasing and the rate of walking and cycling remains low. It is necessary to reverse these negative trends by implementing solu tions based...