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Search results for: WIRELESS MESH NETWORKS
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The networking of the justice system as part of public court networks
PublicationThe goal of this paper is to look at the organizational structure of the justice system and provide the answer to the basic question of the possible network relations, their force, and imapct. As part od the paper, I have defined public inetrorganisational court network, dividing them into regulatory inter-organisational networks nad voluntary inetrorganisational networks. Emphasis has also been placed on the benefits and threats...
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Statistical significance of displacements in heterogeneous control networks
PublicationThis paper proposes a modification of the classical process for evaluating the statistical significance of displacements in the case of heterogeneous (e.g. linear-angular) control networks established to deformation measurements and analysis. The basis for the proposed solution is the idea of local variance factors. The theoretical discussion was complemented with an example of its application on a simulated horizontal control...
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Electrical and noise responses of carbon nanotube networks enhanced by UV light for nitrogen dioxide sensing
Open Research DataNetworks consisting of randomly oriented carbon nanotubes (CNN) were investigated toward nitrogen dioxide detection by means of electrical and low-frequency noise measurements. UV-activation of CNN layers improved gas sensitivity and reduced the limit of detection, especially by employing 275 nm-LED. This data set includes DC resistance measurements...
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Olgun Aydin dr
PeopleOlgun Aydin finished his PhD by publishing a thesis about Deep Neural Networks. He works as a Principal Machine Learning Engineer in Nike, and works as Assistant Professor in Gdansk University of Technology in Poland. Dr. Aydin is part of editorial board of "Journal of Artificial Intelligence and Data Science" Dr. Aydin served as Vice-Chairman of Why R? Foundation and is member of Polish Artificial Intelligence Society. Olgun is...
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Guessing Intrinsic Forwarding Trustworthiness of Wireless Ad Hoc Network Nodes
PublicationA novel node misbehavior detection system called GIFTED is proposed for a multihop wireless ad hoc network (WAHN) whose nodes may selfishly refuse to forward transit packets. The system guesses the nodes’ intrinsic forwarding trustworthiness (IFT) by analyzing end-to-end path performance rather than utilizing unreliable and incentive incompatible low-layer mechanisms. It can work with occasional IFT jumps, directional antennae,...
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Application of wavelength division multiplexing in sensor networks
PublicationOver the past few years the need to acquire data on various parameters from a number of sensors grew. The need that led to the development of a network of sensors which enables simultaneous control and measurement in a wide range of applications. The aim of this article is to discuss a possibility of connecting a variety of sensors in a network that would utilize WDM technology. Wavelength Division Multiplexing is commonly used...
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Karhunen-Loeve-based approach to tracking of rapidly fading wireless communication channels
PublicationWhen parameters of wireless communication channels vary at a fast rate, simple estimation algorithms, such as weighted least squares (WLS) or least mean squares (LMS) algorithms, cannot estimate them with the accuracy needed to secure the reliable operation of the underlying communication systems. In cases like this, the local basis function (LBF) estimation technique can be used instead, significantly increasing the achievable...
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The impact of institutions on innovation networks: empirical evidence from Poland
PublicationInnovation networks may accelerate and improve the innovation process, while institutional pathologies may hamper it. This study employs the Kruskal-Wallis H test and regression analysis to determine if the relationship between institutions and innovation networks does exist among the investigated variables. The purpose of the study was to find out whether cooperation with special local institutions influences the innovative behaviour...
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Mesh-free approach to Helmholtz equation on radial basis functions
PublicationMetoda radialnych funkcji bazowych (RBF) jest coraz czesciej stosowana przy rozwiazywaniu rownan rozniczkowych czastkowych oraz zagadnien wlasnych. W szczegolnosci znalazla ona zastosowanie w problemach elektrodynamiki obliczeniowej. W publikacji zastosowano RBF do rozwiazania rownania Helmholtza. Wprowadzono nowy algorytm - adaptacyjny do wyznaczania centrow interpolacyjnych. Przedstawiona metode zastosowano do wyznaczenia rozkladow...
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Interdependence between Power Grids and Communication Networks: A Resilience Perspective
PublicationPower network resilience is increasingly dependent on communication networks. Besides traditional generation, power networks need to accommodate increasingly high penetration levels of dispersed micro generation, mostly based on renewable sources, and increasing and challenging demand, such as electric vehicles. At the same time the deployment of enabling technologies throughout the power grid makes available new demand resources...
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Traffic Modeling in IMS-based NGN Networks
PublicationIn the modern world the need for accurate and quickly delivered information is becoming more and more essential. In order to fulfill these requirements, next generation telecommunication networks should be fast introduced and correctly dimensioned. For this reason proper traffic models must be identified, which is the subject of this paper. In the paper standardization of IMS (IP Multimedia Subsystem) concept and IMS-based NGN...
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A survey of neural networks usage for intrusion detection systems
PublicationIn recent years, advancements in the field of the artificial intelligence (AI) gained a huge momentum due to the worldwide appliance of this technology by the industry. One of the crucial areas of AI are neural networks (NN), which enable commer‐ cial utilization of functionalities previously not accessible by usage of computers. Intrusion detection system (IDS) presents one of the domains in which neural networks are widely tested...
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Closed-Loop Control System Design for Wireless Charging of Low-Voltage EV Batteries with Time-Delay Constraints
PublicationThis paper presents an inductive power transfer system on the basis of a double single- phase three-level T-type inverter and two split transmitting coils for constant current and constant voltage wireless charging of low-voltage light electric vehicle batteries with closed-loop control, considering time-delay communication constraints. An optimal control structure and a modified control strategy were chosen and implemented to...
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HCI-Based Wireless System for Measuring the Concentration of Mining Machinery and Equipment Operators
PublicationMaintaining stable and reliable working conditions is a matter of vital importance for various companies, especially those involving heavy machinery. Due to human exhaustion, as well as unpredicted hazards and dangerous situations, the personnel has to take actions and wisely plan each move. This paper presents a human–computer interaction (HCI)-based system that uses a concentration level measurement function to increase the safety...
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Performance Analysis of Convolutional Neural Networks on Embedded Systems
PublicationMachine learning is no longer confined to cloud and high-end server systems and has been successfully deployed on devices that are part of Internet of Things. This paper presents the analysis of performance of convolutional neural networks deployed on an ARM microcontroller. Inference time is measured for different core frequencies, with and without DSP instructions and disabled access to cache. Networks use both real-valued and...
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A Novel Multicast Architecture of Programmable Networks
PublicationIn the paper a multicast architecture for programmable networks based on separation of group management and network control tasks is proposed. Thanks to this separation, services which want to make use of multicast communications no longer have to implement low-level network functionalities and their operation is greatly simplified. Abstracting service’s view of the network into a fully connected cloud enables us to transparently...
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Eventual Convergence of the Reputation-Based Algorithm in IoT Sensor Networks
PublicationUncertainty in dense heterogeneous IoT sensor networks can be decreased by applying reputation-inspired algorithms, such as the EWMA (Exponentially Weighted Moving Average) algorithm, which is widely used in social networks. Despite its popularity, the eventual convergence of this algorithm for the purpose of IoT networks has not been widely studied, and results of simulations are often taken in lieu of the more rigorous proof....
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Practical issues for the implementation of survivability and recovery techniques in optical networks
PublicationFailures in optical networks are inevitable. They may occur during work being done for the maintenance of other infrastructures, or on a larger scale as the result of an attack or large-scale disaster. As a result, service availability, an important aspect of Quality of Service (QoS), is often degraded. Appropriate fault recovery techniques are thus crucial to meet the requirements set by the Service Level Agreements (SLAs) between...
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Spectroscopic and Wireless Sensor of Hematocrit Level
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Fundamentals of Communication Networks Resilience to Disasters and Massive Disruptions
PublicationCommunication networks are exposed to a variety of massive failure events following from activities of nature, weather-induced disruptions, technology-implied problems, and malicious human activities. In this chapter, we first highlight the characteristics of these scenarios and discuss example failure events reported during the last three decades. Next, we explain the concept of network resilience and present an overview of major...
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Grade of service determination methodology in IP networks with SIP protocol
PublicationAlthough Grade of Service is very important in VoIP providers evaluation, We wasn't able to find any paper regarding the topic of measuring GoS variables for IP networks utilizing SIP, which are defined like for PSTN/ISDN/GSM networks (post-selection delay, answering delay, release delay, or probability of end-to-end blocking). Due to the lack of research in this field, it was necessary to start from defining measures and cover...
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Polynomial Algorithm for Minimal (1,2)-Dominating Set in Networks
PublicationDominating sets find application in a variety of networks. A subset of nodes D is a (1,2)-dominating set in a graph G=(V,E) if every node not in D is adjacent to a node in D and is also at most a distance of 2 to another node from D. In networks, (1,2)-dominating sets have a higher fault tolerance and provide a higher reliability of services in case of failure. However, finding such the smallest set is NP-hard. In this paper, we...
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Comparison of centralized and decentralized preemption in MPLS networks
PublicationPreemption is one of the crucial parts of the traffic engineering in MPLS networks. It enables allocation of high-priority paths even if the bandwidth on the preferred route is exhausted. This is achieved by removing previously allocated low-priority traffic, so as enough free bandwidth becomes available. The preemption can be performed either as a centralized or a decentralized process. In this article we discuss the differences...
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Mesh-free approach to Helmholtz equation based on radial basis functions.
PublicationW artykule zastosowano metodę radialnych funkcji bazowych do rozwiązania równania Helmholthza oraz zaproponowano nowy (adaptacyjny) algorytm wyznaczania centrów interpolacyjnych. W oparciu o prezentowany schemat wyznaczono długości fal odcięcia dla różnych kształtów przekrojów poprzecznych falowodów cylindrycznych.
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Results of implementation of Feed Forward Neural Networks for modeling of heat transfer coefficient during flow condensation for low and high values of saturation temperature
Open Research DataThis database present results of implementation of Feed Forward Neural Networks for modeling of heat transfer coefficient during flow condensation for low and high values of saturation temperature. Databse contain one table and 7 figures.
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A Review of Traffic Analysis Attacks and Countermeasures in Mobile Agents' Networks
PublicationFor traditional, message-based communication, traffic analysis has been already studied for over three decades and during that time various attacks have been recognised. As far as mobile agents’ networks are concerned only a few, specific-scope studies have been conducted. This leaves a gap that needs to be addressed as nowadays, in the era of Big Data, the Internet of Things, Smart Infrastructures and growing concerns for privacy,...
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Routing decisions independent of queuing delays in broadband leo networks
PublicationThis paper presents an analysis of queuing and propagation delays of Inter-Satellite Links (ISLs) in broadband Low-Earth Orbit (LEO) satellite networks. It is shown that queuing delays are negligible in all reasonable working conditions of the broadband ISL network. This fact makes it possible to simplify the routing protocols in such networks and permits using already known multi-commodity flow solutions for routing. The performance...
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Dynamic Route Discovery Using Modified Grasshopper Optimization Algorithm in Wireless Ad-Hoc Visible Light Communication Network
PublicationIn recent times, visible light communication is an emerging technology that supports high speed data communication for wireless communication systems. However, the performance of the visible light communication system is impaired by inter symbol interference, the time dispersive nature of the channel, and nonlinear features of the light emitting diode that significantly reduces the bit error rate performance. To address these problems,...
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Disaster-resilient communication networks: Principles and best practices
PublicationCommunication network failures that are caused by disasters, such as hurricanes, arthquakes and cyber-attacks, can have significant economic and societal impact. To address this problem, the research community has been investigating approaches to network resilience for several years. However, aside from well-established techniques, many of these solutions have not found their way into operational...
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A Survey of Fast-Recovery Mechanisms in Packet-Switched Networks
PublicationIn order to meet their stringent dependability requirements, most modern packet-switched communication networks support fast-recovery mechanisms in the data plane. While reactions to failures in the data plane can be significantly faster compared to control plane mechanisms, implementing fast recovery in the data plane is challenging, and has recently received much attention in the literature. This survey presents a systematic,...
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Performance Evaluation of Preemption Algorithms in MPLS Networks
PublicationPreemption is a traffic engineering technique in Multiprotocol Switching Networks that enables creation of high priority paths when there is not enough free bandwidth left on the route. Challenging part of any preemption method is to select the best set of paths for removal. Several heuristic methods are available but no wider comparison had been published before. In this paper, we discuss the dilemmas in implementing preemption...
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The searchlight problem for road networks
PublicationWe consider the problem of searching for a mobile intruder hiding in a road network given as the union of two or more lines, or two or more line segments, in the plane. Some of the intersections of the road network are occupied by stationary guards equipped with a number of searchlights, each of which can emit a single ray of light in any direction along the lines (or line segments) it is on. The goal is to detect the intruder,...
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Buck-Boost Inverters with Symmetrical Passive Four-terminal Networks
PublicationAlternating Voltage Inverters (Converters) supplied by low-voltage sources DC (ex. fuel cell, photovoltaic cell) are most frequently realized on the basis of the three fundamental topologies: a) PWM voltage inverter with boost-converter" system, b) PWM voltage inverter with transformed converter DC/DC in the ,,boost-converter" system, c) PWM current converter. However none of these solutions is claimed to be the best and dominant...
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A robust optimization model for affine/quadratic flow thinning: A traffic protection mechanism for networks with variable link capacity
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Krzysztof Cwalina dr inż.
PeopleKrzysztof Kamil Cwalina w 2013 r. uzyskał tytuł inżyniera na Wydziale Elektroniki, Telekomunikacji i Informatyki Politechniki Gdańskiej; w 2014 r. uzyskał tytuł magistra inżyniera, a w 2017 r. otrzymał stopień doktora nauk technicznych w dyscyplinie: telekomunikacja, także na WETI PG. Aktualnie pracuje na stanowisku adiunkta w Katedrze Systemów i Sieci Radiokomunikacyjnych Wydziału Elektroniki, Telekomunikacji i Informatyki Politechniki...
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Deep neural networks approach to skin lesions classification — A comparative analysis
PublicationThe paper presents the results of research on the use of Deep Neural Networks (DNN) for automatic classification of the skin lesions. The authors have focused on the most effective kind of DNNs for image processing, namely Convolutional Neural Networks (CNN). In particular, three kinds of CNN were analyzed: VGG19, Residual Networks (ResNet) and the hybrid of VGG19 CNN with the Support Vector Machine (SVM). The research was carried...
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Spectrum Sensing Based on Hybrid Spectrum Handoff in Cognitive Radio Networks
PublicationThe rapid advancement of wireless communication combined with insufficient spectrum exploitation opens the door for the expansion of novel wireless services. Cognitive radio network (CRN) technology makes it possible to periodically access the open spectrum bands, which in turn improves the effectiveness of CRNs. Spectrum sensing (SS), which allows unauthorized users to locate open spectrum bands, plays a fundamental part in CRNs....
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Clothes Detection and Classification Using Convolutional Neural Networks
PublicationIn this paper we describe development of a computer vision system for accurate detection and classification of clothes for e-commerce images. We present a set of experiments on well established architectures of convolutional neural networks, including Residual networks, SqueezeNet and Single Shot MultiBox Detector (SSD). The clothes detection network was trained and tested on DeepFashion dataset, which contains box annotations...
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Towards 5G — Cloud-based Radio Access Networks
PublicationIn the paper a general concept of the 5G network architecture is presented as well as system requirements having impact on innovative solutions in the 5G network are highlighted. A major part of the paper is both presentation and discussion of the problem of Cloud Radio Access Network introduction for public networks in which the cell and resource virtualisation will be implemented. On the other hand, the problem of resource virtualization...
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Towards the boundary between easy and hard control problems in multicast Clos networks
PublicationIn this article we study 3-stage Clos networks with multicast calls in general and 2-cast calls, in particular. We investigate various sizes of input and output switches and discuss some routing problems involved in blocking states. To express our results in a formal way we introduce a model of hypergraph edge-coloring. A new class of bipartite hypergraphs corresponding to Clos networks is studied. We identify some polynomially...
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A MODEL FOR FORECASTING PM10 LEVELS WITH THE USE OF ARTIFICIAL NEURAL NETWORKS
PublicationThis work presents a method of forecasting the level of PM10 with the use of artificial neural networks. Current level of particulate matter and meteorological data was taken into account in the construction of the model (checked the correlation of each variable and the future level of PM10), and unidirectional networks were used to implement it due to their ease of learning. Then, the configuration of the network (built on the...
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Wireless short-range device for wind generators
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Wireless Multihoming Modeled as a Multi-WLAN Game
PublicationZbadano strategie wieloetapowe dostępu do medium transmisyjnego oparte na tzw. wypłatach wirtualnych, biorąc pod uwagę wybór sieci lokalnej oraz stopień agresji konfiguracji protokołu MAC. Zakładano obecność stacji-agresora o idealnie predykcyjnej strategii dostępu. Wykazano możliwość zniechęcania takiego agresora za cenę niewielkiego spadku wydajności sieci.
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Limiting influence of wireless network emissions on environment
PublicationW pracy proponowany jest sposób zarządzania parametrami kanału radiowego w sieciach WiFi. Rozwiązanie oparte jest o niestosowaną dotąd w sieciach bezprzewodowych metodę pomiaru odległości stacji klienckiej od punktu dostępowego. Wymagane jest zmodyfikowanie warstwy MAC zarówno punktów dostępowych, jak i stacji klienckich. Możliwa jest także praca z typowymi kartami bezprzewodowymi.Zaproponowane rozwiązanie pozwala znacząco podnieść...
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Self-Organizing Wireless Monitoring System for Containers
PublicationThis paper presents a description of new global monitoring system for containers, with its layer-modular structure, as a solution for enhance security and efficiency of container transport with particular emphasis on the practical implementation of that system for maritime container terminals. Especially the Smart Container Module (SCM) architecture and its operation as a part of the Self-Organizing Container Monitoring Network...
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Wireless control process technical exploitation facility
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A wireless network for off-shore marine research
PublicationThis paper presents functionality, the most important technology developments and potential use cases of digital communication system, developed to facilitate selected tasks commonly required during off-shore operations and marine research, including: broadband information sharing between platforms isolated from an on-shore communication infrastructure, acquisition of large data-sets from variety of off-shore...
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IET Wireless Sensor Systems
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International Journal of Wireless Communication
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QoS Resource Reservation Mechanisms for Switched Optical Networks
PublicationThe paper regards the problem of resource reservation mechanisms for Quality of Service support in switched optical networks. The authors propose modifications and extensions for resources reservation strategy algorithms with resources pools, link capacity threshold and adaptive advance reservation approach. They examine proposed solutions in Automatically Switched Optical Network with Generalized Multi-Protocol Label Switching...