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Search results for: SHORTEST PATH PROBLEM
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A system for acoustic field measurement employing cartesian robot
PublicationA system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity (vector) quantities. The aim of the...
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Characteristics of Propagation Conditions in the Container Terminal Environment
PublicationIn the paper a characteristics of propagation conditions in the container terminal environment is presented. The investigated environment is characterized on the example of Gdansk Deepwater Container Terminal in Poland. An empirical propagation model for path loss calculation in mobile radio links in a container terminal environment is presented.
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Group project (NT2-eng. sem.3) - 2022
e-Learning CoursesCourse for 2nd degree Students of Nanotechnology, sem. 3, academic year 2022/2023. The aim of the course is to prepare students for teamwork by implementing a project involving the analysis of the problem by the team, presenting a proposal to solve the problem, conducting research/tests and preparing a report.
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Optimal edge-coloring with edge rate constraints
PublicationWe consider the problem of covering the edges of a graph by a sequence of matchings subject to the constraint that each edge e appears in at least a given fraction r(e) of the matchings. Although it can be determined in polynomial time whether such a sequence of matchings exists or not [Grötschel et al., Combinatorica (1981), 169–197], we show that several questions about the length of the sequence are computationally intractable....
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Jerzy Konorski dr hab. inż.
PeopleJerzy Konorski received his M. Sc. degree in telecommunications from Gdansk University of Technology, Poland, and his Ph. D. degree in computer science from the Polish Academy of Sciences, Warsaw, Poland. In 2007, he defended his D. Sc. thesis at the Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology. He has authored over 150 papers, led scientific projects funded by the European Union,...
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Acoustic Processor of the MCM Sonar
PublicationThis paper presents the concept of an acoustic processor of the mine countermeasure sonar. Developed at the Department of Marine Electronics Systems, Gdansk University of Technology, the acoustic processor is an element of the MG-89, a modernised underwater acoustic station. The focus of the article is on the modules of the processor. They are responsible for sampling analogue signals and implementing the algorithms controlling...
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Collision-free network exploration
PublicationMobile agents start at different nodes of an n-node network. The agents synchronously move along the network edges in a collision-free way, i.e., in no round two agents may occupy the same node. An agent has no knowledge of the number and initial positions of other agents. We are looking for the shortest time required to reach a configuration in which each agent has visited all nodes and returned to its starting location. In...
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Cops, a fast robber and defensive domination on interval graphs
PublicationThe game of Cops and ∞-fast Robber is played by two players, one controlling c cops, the other one robber. The players alternate in turns: all the cops move at once to distance at most one each, the robber moves along any cop-free path. Cops win by sharing a vertex with the robber, the robber by avoiding capture indefinitely. The game was proposed with bounded robber speed by Fomin et al. in “Pursuing a fast robber on a graph”,...
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The reliability of tree and star networks
PublicationThis paper investigated the reliability of tree and star networks. Following measures of network reliability are assumed: the expected number of nodes, that can communicate with the central node; the expected number of node pairs, that are connected by a path through the central node; the expected number of node pairs communicating.
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Wybrane elementy nieliniowej dynamiki struktur kratowych
PublicationW pracy jest dyskutowany problem nieliniowej dynamiki struktur kratowych. Zastosowano stacjonarny opis Lagrange'a (ang. Total Lagrange), pokazano silne i słabe sformułowanie dla pręta kratowego, jego aplikację do MES. W zakresie całkowania równań ruchu przedstawiono metodę Newmarka i metodę-a dla problemów liniowych i nieliniowych. Załączony przykład numeryczny ilustruje cechy przedstawionych metod.
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Proportional-Derivative and Model-Based Controllers for Control of a Variable Mass Manipulator
PublicationIn the paper, numerical analysis of dynamics of a variable mass manipulator is presented. A revolute joints composed manipulator is considered. Payload of the gripper is considered as the only element characterized by unknown value of its mass (variable between subsequent operations). As in other cases of the revolute joints composed manipulators, its behaviour dependents significantly on the pose of the manipulator. When the manipulator...
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Minimizing Greenhouse Gas Emissions From Ships Using a Pareto Multi-Objective Optimization Approach
PublicationTo confront climate change, decarbonization strategies must change the global economy. According to statements made as part of the European Green Deal, maritime transport should also become drastically less polluting. As a result, the price of transport must reflect the impact it has on the environment and on health. In such a framework, the purpose of this paper is to suggest a novel method for minimizing emissions...
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Energy roadmaps for the city of Gdańsk
PublicationThe paper presents energy roadmaps for Gdansk in three time perspectives: short-term (the year 2012), medium-term (2020) and long-term (2050). The paper is a result of the research carried out under the PATH-TO-RES project, supported by European Commission programme SAVE Altener Intelligent Energy Europe.
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Modelowanie bezpiecznika rozłącznikowego w układach formowania impulsów wielkiej mocy
PublicationProblem modelowania bezpieczników o dużej dynamice wyłączania prądu jest zagadnieniem szeroko opisywanym w literaturze. Układy takie mogą być wykorzystane w szczególności do formowania impulsów wysokiego napięcia o wartościach rzędu setek kV, charakteryzujących się czasem trwania rzędu ułamka μs. W niniejszej pracy przedstawiono empiryczny model bezpiecznika wielotopikowego, rozszerzony w oparciu o wyniki badań eksperymentalnych.
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Dedicated scheduling of tasks to minimize mean flow time
PublicationThis paper investigates the complexity of scheduling biprocessor tasks on dedicated processors to minimize mean flow time. Since the general problem is strongly NP-hard, we assume some restrictions on task lengths and the structure of associated scheduling graphs. Of particular interest are acyclic graphs. In this way we identify a borderline between NP-hard and polynomially solvable special cases.
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High-Power Jamming Attack Mitigation Techniques in Spectrally-Spatially Flexible Optical Networks
PublicationThis work presents efficient connection provisioning techniques mitigating high-power jamming attacks in spectrally-spatially flexible optical networks (SS-FONs) utilizing multicore fibers. High-power jamming attacks are modeled based on their impact on the lightpaths’ quality of transmission (QoT) through inter-core crosstalk. Based on a desired threshold on a lightpath’s QoT, the modulation format used, the length of the path,...
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Propagation of Acoustic Disturbances in Shallow Sea
PublicationPropagation of acoustic waves in shallow sea differs fundamentally from the same phenomenon occurring in deep sea in view of non-negligible distance from the sea bottom in the first case, where presence of two regions limiting the water layer results in the acoustic pressure distribution induced by a harmonic source has an interferential nature as a result of multi-path propagation of the acoustic signal. These interferential properties...
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Smart Services supporting Drivers in Effective Cars Parking
PublicationThe paper shows how to design and implement intelligent, service oriented systems for management of free places in distributed car parks. The idea of SOA technology is widely used. It is assumed that a state of every car park is automatically determined by a special electronic infrastructure including IoT solutions. The information received from such an infrastructure is sent to the main management system, which processes it and,...
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Client-server Approach in the Navigation System for the Blind
PublicationThe article presents the client‐server approach in the navigation system for the blind ‐ “Voice Maps”. The authors were among the main creators of the prototype and currently the commercialization phase is being finished. In the implemented prototype only exemplary, limited spatial data were used, therefore they could be stored and analysed (for path-finding process) in the mobile device’s memory without any difficulties. The...
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Analiza numeryczna i analityczna przekrycia w kształcie powłoki synklastycznej o podstawie kwadratowej
PublicationW pracy poruszono problem obliczania przekrycia żelbetowego w kształcie powłoki synklastycznej ściętej o podstawie kwadratowej. Przedstawiono obliczenia analityczne i numeryczne sił w powłoce. Powłoka jest poddana działaniu głównie sił ściskających, co jest korzystne dla tego typu konstrukcji. W strefie brzegowej i podporowej konieczne jest wymiarowanie na mimośrodowe ściskanie i rozciąganie z uwagi na znaczący wzrost momentów...
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Sterowanie optyczną siecią wielodomenową z hierarchiczną strukturą płaszczyzn sterowania
PublicationW artykule przedstawiono problem sterowania wielodomenową siecią optyczną z hierarchiczną strukturą płaszczyzn sterowania. Autorzy proponują wykorzystanie koncepcji sieci ASON/GMPLS, która spełnia wymagania nowoczesnych sieci optycznych, a jednocześnie umożliwia sterowanie wielodomenową siecią z gwarancją jakości usług. W artykule zaproponowano algorytm sterowania z gwarancją jakości, którego efektywność zweryfikowano metodą symulacji...
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Stateczność i niezawodność pełnomorskich platform wiertniczych
PublicationW pracy przedstawiono wieloletnie doświadczenia Autora w zakresie wybranych aspektów numerycznej analizy pełnomorskich platform wiertniczych, w szczególności stacjonarnych platform stalowych poddanych działaniu fal wiatrowych i wiatru. W opisie zachowania się platform uwzględniono współoddziaływanie trzech ośrodków: materiału konstrukcji, morskich fal wiatrowych i podłoża gruntowego. Przyjęcie do opisu stochastycznych właściwości...
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Agnieszka Mikołajczyk-Bareła dr inż.
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Theorey of Urbanism
e-Learning CoursesThis course provides an insight into the current urban design and planning issues takin into account main problem issues associated with contemporary urban development.
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The voltage on bus bars of the main switchboard of the car carrier electrical power system during sea trials
Open Research DataThe dataset is part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the measurement results conducted onboard the car carrier during sea trials.
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The voltage on bus bars of the main switchboard of the car carrier electrical power system at sea trials during maneuvering
Open Research DataThe dataset is part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the measurement results conducted onboard the car carrier at sea trials during maneuvering.
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Marek Chodnicki dr inż.
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Approximate models and parameter analysis of the flow process in transmission pipelines
Publicationthe paper deals with the problem of early leak detection in transmission pipelines. First we present the derivation of state-space equations of the flow process in the pipelines. This description is then aggregated in order to obtain a principal model. Next, the problem of process model parameterization is addressed, taking into account the maximization of a model stability margin. The location of the maximum is determined using...
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Multi-objective optimization of microwave couplers using corrected domain patching
PublicationPractical design of microwave components and circuits is a compromise between various, often conflicting objectives. In case of compact structures, the trade-offs are typically concerned with the circuit size and its electrical performance. Comprehensive information about the best possible trade-offs can be obtained by means of multi-objective optimization. In this paper, we propose a computationally efficient technique for identifying...
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Classification of submandibular salivary stones based on ultrastructural studies
PublicationIntroduction: Sialolithiasis remains a clinical problem with unclear etiopathogenesis, lack of prevention methods, and only surgical treatment. Materials and methods: An ultrastructure examination of submandibular sialoliths obtained from patients with chronic sialolithiasis was conducted using a scanning electron microscope and X‐ray photoelectron spectroscopy. Results: Based on the results, we divided sialoliths into three types:...
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Der Begriff des Mythos bei Cassirer: zwischen UIdealismus, Ethnologie, politischer Philosophie und allgemeine Kulturphilosophie
PublicationDer Mythos war eines der bevorzugten Forschungsobjekte Cassirers, denen er zwei Bücher, zahlreiche Artikel und wichtige längere Aufsätze widmete. In diesem Artikel versuche ich Cassirers Mythendeutung kurz zu rekapitulieren, um ihre Position in der Gesamtheit seines philosophischen Systems festzulegen und ihr Erklärungspotenzial zu gewinnen. In erstem Teil handle ich das allgemeine Problem des mythischen Denkens hauptsächlich aufgrund...
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Bezpieczeństwo elektroenergetyczne dla pokoleń
PublicationW artykule przeanalizowano źródła energii pierwotnej, ich wystarczalnośći dywersyfikację w skali lokalnej i globalnej, problem dekarbonizacji polskiej elektroenergetyki na tle europejskiej polityki klimatycznej, osiągalność źródeł gazu jako efektywnego paliwa dla energetyki, polski program energetyki jądrowej, bezpieczeństwo zasilania elektrycznych systemów trakcyjnych jako strategicznej alternatywy...
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Reactions of methyl radicals with silica supported silver nanoparticles in aqueous solutions
PublicationSilica supported silver nanoparticles (Ag°–SiO2 –NCs, NCs=nanocomposites) suspended in aqueous solutions are efficient catalysts for the dimerization of methyl radicals to produce ethane, while bare silica is quite inert towards the interaction with methyl radicals. In the presence of small amounts of ethanol adsorbed on the SiO2 surface, the reaction path with methyl radicals is changed and methane is formed as the major product.
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Green function diagonal for a class of heat equations
PublicationA construction of the heat kernel diagonal is considered as element of generalized zeta function theory, which gradient at the origin defines determinant of a differential operator in a technique for regularizing quadratic path integral. Some classes of explicit expressions of the Green function in the case of finite-gap potential coefficient of the heat equation are constructed. An algorithm and program for Mathematica are presented...
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OCENA EFEKTYWNOŚCI DZIAŁALNOŚCI BADAWCZO-ROZWOJOWEJ W KRAJACH OECD
PublicationDziałalność badawczo-rozwojowa jest istotną częścią polityki innowacyjnej. Ocenę tej działalności w krajach OECD przeprowadzono wykorzystując metodę DEA. Uwzględniono nakłady: poziom wykształcenia, współpracę nauki z biznesem i poziom wykorzystywania wiedzy w firmach oraz rezultaty: liczba publikacji, patentów i doktoratów oraz eksport sektorów wysokich technologii i indeks Hirsha. Zwrócono uwagę na problem zerowych wag oraz przesunięcia...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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Rewitalizacja zespołow fortyfikacji nowożytnych - ograniczenia i możliwości
PublicationFortyfikacjenowożytne stanowią w Polsce liczną grupę zabytków, trudną do utrzymywania i zarządzania co powoduję ich postępującą degradację. Wskutek zmian polityczno-ekonomicznych w ostatnich dekadach, powstał problem chaotycznych i agresywnych działań inwestycyjnych, zagrażających zabytkowym fortyfikacjom. Tekst omawia fortyfikacje jako część dziedzictwa kulturowego, sprzecznośći pomiędzy pojęciami "rewitalizacji" i "rewaloryzacji"...
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Increased Certification of Semi-device Independent Random Numbers using Many Inputs and More Postprocessing
PublicationQuantum communication with systems of dimension larger than two provides advantages in information processing tasks. Examples include higher rates of key distribution and random number generation. The main disadvantage of using such multi-dimensional quantum systems is the increased complexity of the experimental setup. Here, we analyze a not-so-obvious problem: the relation between randomness certification and computational requirements...
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Przedsiębiorczość społeczna jako klucz do skutecznej edukacji przedsiębiorczej na społecznie odpowiedzialnym uniwersytecie
PublicationCel naukowy: Celem artykułu jest prezentacja nowej propozycji kształcenia na rzecz przedsiębiorczości na studiach biznesowych (zarządzanie i ekonomia), uwzględniającej edukację w zakresie przedsiębiorczości społecznej. Problem i metody badawcze: W artykule omówiono problem edukacji przedsiębiorczej z punktu widzenia wyzwań zmieniającej się gospodarki oraz ewoluujących oczekiwań stawianych polskim uczelniom wyższym. Główną metodą...
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Empirical Adjustment of the Selected Propagation Models for Application in the Peculiar Environment of the Container Terminal
PublicationIt is important to look for any propagation model that could be useful for designing mobile radio systems in container terminal environment. Selected propagation models have been investigated. The applied research methodology has been described too. Results of the statistical adjustment in terms of signal loss determination in such environment have been analysed. The analysis has proved effectiveness of adjustment by increasing...
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Selected Propagation Models Modification for Application in Container Terminal
PublicationIt is particularly important to look for any propagation model that could be useful for designing mobile radio systems in container terminal environment. The selected propagation models have been investigated. The applied research methodology has been described too. Results of the statistical adjustment in terms of signal loss determination in such environment have been analysed. The analysis have proved effectiveness of adjustment...
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Performance Assessment of Using Docker for Selected MPI Applications in a Parallel Environment Based on Commodity Hardware
PublicationIn the paper, we perform detailed performance analysis of three parallel MPI applications run in a parallel environment based on commodity hardware, using Docker and bare-metal configurations. The testbed applications are representative of the most typical parallel processing paradigms: master–slave, geometric Single Program Multiple Data (SPMD) as well as divide-and-conquer and feature characteristic computational and communication...
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An approach to improve the time efficiency of disjoint paths calculation
PublicationFailures of network elements can be appropriately dealt with by utilization of alternate disjoint paths to provide redirection of flows affected by failures of the respective working paths. Known approaches can be broadly divided by decision on backup paths installation into proactive and reactive mechanisms, as well as based on the scope of recovery actions into local and global rerouting. There are several important scenarios...
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Methane (CH4) calibration set of FTIR spectra
Open Research DataThe calibration spectra for CH4 concentration calibration were supplied with this dataset
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Carbon (II) oxide (CO) calibration set of FTIR spectra
Open Research DataThe calibration spectra for CO concentration calibration were supplied with this dataset
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Carbon dioxide (CO2) calibration set of FTIR spectra
Open Research DataThe calibration spectra for CO2 concentration calibration were supplied with this dataset
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Constant-Factor Approximation Algorithm for Binary Search in Trees with Monotonic Query Times
PublicationWe consider a generalization of binary search in linear orders to the domain of weighted trees. The goal is to design an adaptive search strategy whose aim is to locate an unknown target vertex of a given tree. Each query to a vertex v incurs a non-negative cost ω(v) (that can be interpreted as the duration of the query) and returns a feedback that either v is the target or the edge incident to v is given that is on the path towards...
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Asynchronous distributed state estimation for continuous-time stochastic processes
PublicationWe consider the problem of state estimation of a continuous-time stochastic process using an asynchronous distributed multi-sensor estimation system (ADES). In an ADES the state of a process of interest is estimated by a group of local estimators. Each local estimator based, for example, on a Kalman filter, performs single sensor filtration but also fusion of its local results and results from other (remote) processors to compute...
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Data obtained by numerical simulation for X-ray focusing using a finite difference method
Open Research DataThe propagation of X-ray waves through an optical system consisting of many X-ray refractive lenses is considered. For solving the problem for an electromagnetic wave, a finite-difference method is applied.