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Reliable routing and resource allocation scheme for hybrid RF/FSO networks
PublikacjaSignificant success of wireless networks in the last decade has changed the paradigms of communication networks design. In particular, the growing interest in wireless mesh networks (WMNs) is observed. WMNs offer an attractive alternative to conventional cable infrastructures, especially in urban areas, where the cost of new installations is almost prohibitive. Unfortunately, the performance of WMNs is often limited by the cluttered...
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A Multi-Antenna Scheme for Early Detection and Mitigation of Intermediate GNSS Spoofing
PublikacjaThis article presents a method for detecting and mitigating intermediate GNSS spoofing. In this type of attack, at its early stage, a spoofer transmits counterfeit signals which have slight time offsets compared to true signals arriving from satellites. The anti-spoofing method proposed in this article fuses antenna array processing techniques with a multipath detection algorithm. The latter is necessary to separate highly correlated...
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A note on an approximative scheme of finding almost homoclinic solutions for Newtonian systems
PublikacjaIn this work we will be concerned with the existence of an almost homoclinic solution for a perturbed Newtonian system in a finite dimensional space. It is assumed that a potential is C^1 smooth and its gradient is bounded with respect to a time variable. Moreover, a forcing term is continuous, bounded and squere integrable. We will show that the appproximative scheme due to J. Janczewska for a time periodic potential extends to...
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Performance of Coherent Modulation Scheme Used in Acoustic Underwater Communication System
PublikacjaThe development of an acoustic underwater communication system for shallow waters is still a big scientificand construction challenge. Currently, non-coherent modulations in combination with strong channel coding are used to achieve reliable communication with low rate in such a channel. To obtain transmission with a higher transmission rate, it is required to use coherent modulation. This paper presents the assumptions of such...
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Photovoltaic effect in hybrid heterojunction formed from cadmium telluride and zinc perfluorophthalocyanine layers
PublikacjaPraca przedstawia wyniki badań zjawska fotowoltaicznego w planarnym układzie złożonym z następujących warstw: ITO, CdTe, perfluoroftalocyjanina cynku, BCP, Ag.
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Modeling the electrical characteristics of P3HT:PCBM bulk heterojunction solar cells: Influence of the interface recombination
PublikacjaThe interface recombination of charge carriers located in the material with lower permittivity (Szmytkowski 2009 Chem.Phys.Lett. 470 123) has been implemented for the first time to calculate the electrical characteristics of the donor-acceptor P3HT:PCBM bulk heterojunction solar cell. In order to estimate the photocurrent density in this system, a simple analytical formula has been derived. We have obtained a very good agreement...
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On photovoltaic effect in hybrid heterojunction formed from palladium phthalocyanine and titanium dioxide layers
PublikacjaPraca omawia własności fotowoltaiczne hybrydowego heterozłączy utworzonego z ftalocyjaniny palladu i dwutlenku tytanu. Warstwy TiO2 otrzymano metodą zol-żel, a warstwę organiczną nanoszono metodą próżniowego naparowywania. W pracy przedstawione są charakterystyki prądowo-napięciowe, zależność prądu zwarcia i napięcia rozwarcia od natężenia oświetlenia oraz spektralna charakterystyka prądu zwarcia.
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Nongeminate recombination in organic bulk heterojunction solar cells: Contribution of exciton–polaron interaction
PublikacjaA new model to explain nongeminate recombination in organic bulk heterojunction solar cells is presented. We suggest that the annihilation of excitons on charge carriers at the interface between donor and acceptor phases competes with the bimolecular recombination of Coulombically bound electron–hole pairs. The exciton–polaron interaction gives visible contribution to the reduction of Langevin recombination. An analytical formula,...
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Microwave-assisted synthesis of a TiO2-CuO heterojunction with enhanced photocatalytic activity against tetracycline
PublikacjaA microwave method was used for the synthesis of TiO2-CuO oxide systems. A detailed investigation was made of the effect of the molar ratio of components (TiO2:CuO=9:1, 7:3, 5:5, 3:7, 1:9) on the crystalline structure and morphology. Transmission electron microscopy (TEM) confirmed the presence of octahedral and rod-shaped titania particles and sheet copper(II) oxide particles; moreover, HRTEM analysis indicated the presence of...
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The influence of the Cu2O deposition method on the structure, morphology and photoresponse of the ordered TiO2NTs/Cu2O heterojunction
PublikacjaThe increased interest in highly ordered titania structures exhibiting tubular shape that could be directly formed onto the stable substrate is related with the intensive research on their modification enabling absorption of light within the wide solar spectrum and its further conversion into electric or chemical energy. Among others, formation of uniform 3D heterojunctions based on the TiO2 nanotubes attracts attention since porous...
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A perfect hashing incremental scheme for unranked trees using pseudo-minimal automata
PublikacjaWe describe a technique that maps unranked trees to arbitrary hash codes using a bottom-up deterministic tree automaton (DTA). In contrast to other hashing techniques based on automata, our procedure builds a pseudo-minimal DTA for this purpose. A pseudo-minimal automaton may be larger than the minimal one accepting the same language but, in turn, it contains proper elements (states or transitions that are unique) for every input...
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Relativistic Bennett Brassard cryptographic scheme, relativistic errors,and how to correct them.
PublikacjaWprowadzono opis polaryzacji liniowej oparty o główne zerowe kierunki transformacji Lorentza. Formalizm ten został zastosowany do problemu eliminacji błędów w kryptografii kwantowej.
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Dynamics based on six-field theory of shells in the context of energy-conserving scheme
PublikacjaPraca dotyczy zaproponowanego algorytmu zachowującego energię w całkowaniu równań ruchu powłok sprężystych sformułowanych w ramach teorii sześcioparametrowej. Zawiera podstawowe założenia konieczne do formułowania schematów i podstawowe testy numeryczne. Aproksymacja przestrzenna zagadnienia oparta jest o Metodę Elementów Skończonych zaś aproksymacja w czasie wykorzystuje regułę punktu środkowego. Przykłady analizy dynamicznej...
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LLA : A New Anypath Routing Scheme Providing Long Path Lifetime in VANETs
PublikacjaVehicular ad-hoc networks (VANETs) are a promising solution to improve the road traffic safety, reduce the environmental pollution, or simply provide the on-board infotainment services. However, these actions are often not possible due to high mobility of vehicles causing frequent failures of VANET links. In this paper, we focus on anypath routing to improve the reliability of multihop VANET communications. In particular, the paper...
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Logical Interface for Soft Handover – an effective scheme of handovers in Proxy Mobile IPv6
PublikacjaMultimedia services are currently commonly available on mobile devices. Due to networks' convergence and migration to all-IP networks, mobility management at network layer is required. Moreover, nowadays it is popular to equip mobile devices with more than one wireless interface. Thus, soft handovers can be implemented, which means that an existing connection is removed after a new one is established. Usage of the Logical Interfaces...
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Cable-stayed bridges. Basic static schemes
PublikacjaThe paper presents an overview of shaping of cable-stayed bridges. Historical background, basic static sketches and overview of selected bridges are included. Selected natural solutions and interesting unrealized projects were presented. Basic ideas and most important principals are discussed. The examples and sketches were given an author's comment. Static diagrams of two pylon structures with three variants of the arrangement...
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Disaster-Resilient Routing Schemes for Regional Failures
PublikacjaLarge-scale natural disasters can have a profound effect on the telecommunication services in the affected geographical area. Hence, it is important to develop routing approaches that may help in circumventing damaged regional areas of a network. This prompted the development of geographically diverse routing schemes and also of disaster-risk aware routing schemes. A minimum-cost geodiverse routing, where a minimum geographical...
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Electroactive heterojunctions of iron-based compounds in oxygen evolution reaction—Insight into synergy and mechanism
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Kinetic flux vector splitting scheme for solving non-reactive multi-component flows
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Improving the accuracy of subgridding scheme in finite differences method based on Legendre polynomials expansion
PublikacjaIn this article the Legendre polynomials have been used to interpolate the field at the boundary of the meshes of different densities. The numerical verification of the proposed technique has been carried out in frequency domain. It has been shown that the accuracy of the presented method is very high and stable - the error monotonically decreases as a function of the refinement factor.
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Capacity efficient shared protection and fast restoration scheme in self-configured optical networks
PublikacjaW artykule zaproponowano nową koncepcję optymalizacji rozdziału zasobów dla przeżywalnych sieci rozległych, która gwarantuje szybkie odtwarzanie usług po wystąpieniu awarii. Wykazano, iż proponowany algorytm, wykorzystujący ideę wierzchołkowego kolorowania grafów, nie powoduje wydłużania ścieżek zabezpieczających - zjawiska charakterystycznego dla powszechnie stosowanych algorytmów optymalizacji. Udowodniono, iż powyższa cecha...
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A fast high-resolution 3-D Finite Difference Time-Domain scheme with macromodels.
PublikacjaZaprezentowano szybki trójwymiarowy wysokorozdzielczy algorytm różnic skończonych w dziedzinie czasu. Zwiększona rozdzielczość osiągnięta została poprzez połączenie standardowego schematu FDTD z makromodelami silnie zagęszczonych objętości stworzonych przez zastosowanie redukcji rzędu modelu. Nowy schemat FDTD z makromodelami jest wyprowadzony. Koszt numeryczny nowej metody jest wyestymowany. Doskonałe wyniki zostały zaobserwowane...
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A Reputation Scheme to Discourage Selfish QoS Manipulation in Two-Hop Wireless Relay Networks
PublikacjaIn wireless networks, stations can improve their received quality of service (QoS) by handling packets of source flows with higher priority. Additionally, in cooperative relay networks, the relays can handle transit flows with lower priority. We use game theory to model a two-hop relay network where each of the two involved stations can commit such selfish QoS manipulation. We design and evaluate a reputation-based incentive scheme...
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Numerical simulation of transient flow in storm sewers using standard and improved mccormack scheme
PublikacjaProblem przepływu wody w rurach kanalizacji deszczowej wiąże się z pewnymi specyficznymi zjawiskami zachodzącymi w przewodach podczas zjawisk burzowych. Jeśli rury zaczynają być całkowicie wypełnione wodą, można zaobserwować przejście z ruchu ze swobodną powierzchnią do ruchu pod ciśnieniem i odwrotnie. Takie zjawisko można zaobserwować również w kanałach kontrolowanych przez urządzenia sterujące, np. zasuwy. Ponadto ruch szybkozmienny...
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Numerically efficient algorithm for compact microwave device optimization with flexible sensitivity updating scheme
PublikacjaAn efficient trust-region algorithm with flexible sensitivity updating management scheme for electromagnetic (EM)-driven design optimization of compact microwave components is proposed. During the optimization process, updating of selected columns of the circuit response Jacobian is performed using a rank-one Broyden formula (BF) replacing finite differentiation (FD). The FD update is omitted for directions sufficiently well aligned...
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Analysis of the image force effects on the recombination at the donor-acceptor interface in organic bulk heterojunction solar cells
PublikacjaWe consider the influence of image force effects on the recombination at the donor-acceptor interface in organic bulk heterojunction solar cells. The conclusion is that the charge carriers of one sign located in the material with lower permittivity recombine at the boundary between donor and acceptor phases. This process competes with the recombination of opposite sign charge carriers, leading to the reduction of the Langevin-type...
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Effect of buffer layers on performance of organic photovoltaic devices based on copper phthalocyanine-perylene dye heterojunction
PublikacjaPraca przedstawia wyniki badań układu fotowoltaicznego złożonego z cienkich warstw organicznych tworzących złącze (CuPc i MePTCDI), elektrod (ITO i Ag) oraz z warstw buforowych (MoO3 przy ITO i BCP przy Ag).
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On the tendency of temperature and electric field dependences of interface recombination in P3HT:PCBM organic bulk heterojunction solar cells
PublikacjaWe demonstrate theoretical explanation of the temperature and electric field dependences of recombination coefficients in an organic P3HT:PCBM bulk heterojunction solar cell. Based onthe model of interface recombination, two analytical formulas describing the relative ratio of the interface (γI ) to the Langevin (γL) recombination coefficients have been derived. Our analysis indicates that the sign of parameters φT and φF determines...
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Pilot-Scale Studies of WO3/S-Doped g-C3N4 Heterojunction toward Photocatalytic NOx Removal
PublikacjaDue to the rising concentration of toxic nitrogen oxides (NOx) in the air, effective methods of NOx removal have been extensively studied recently. In the present study, the first developed WO3/S-doped g-C3N4 nanocomposite was synthesized using a facile method to remove NOx in air efficiently. The photocatalytic tests performed in a newly designed continuous-flow photoreactor with an LED array and online monitored NO2 and NO system...
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A Database Schema for the Analysis of Global Dynamics of Multiparameter Systems
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Comparison of Selection Schemes in Evolutionary Method of Path Planning
PublikacjaThis article compares an impact of using various selection schemes on the quality of the solution for the problem of planning the path for a moving object using the evolutionary method. In study case problem of avoiding collisions at sea is analyzed. The modelled environment includes static constraints (lands, canals, etc.) and dynamic objects (moving ships). Article analyses behaviour of selection schemes in two similar environments...
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Evaluation of time-efficiency of disjoint paths calculation schemes
PublikacjaThe concept of alternate paths has been shown in the literature to provide fast response of a network to failures of its elements (nodes/links) affecting flows along the primary communication paths. Various approaches have been proposed to reduce the time necessary to redirect the respective flows onto the alternate paths. In this paper, we focus on another important objective, that so far has not received much attention, i.e.,...
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Sphere of interests of econophysics
PublikacjaW niniejszym rozdziale omówiono niektóre zagadnienia, jakimi zajmuje się ekonofizyka. W pracy podano relacje pomiędzy ekonomią i mechaniką, omówiono systemy złożone i model Blacka- Scholesa oraz zajęto się omówieniem modelu wzrostu wartości firm i PKB państw. Ponadto wskazano na problemy, oraz szanse, jakie stoją przed ekonofizyką.
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On the safety of technical sphere.
PublikacjaTechnika daje nam dobra użyteczne i zarazem generuje rozmaite zagrożenia.Przedstawiono analizę tych zagrożeń na przykładzie ogólnie potraktowanego systemu realizacji potrzeb. Opisana została natura relacji występujących między tym systemem a otoczeniem oraz w jego wnętrzu. Dalej przedstawiono klasy modeli predykcji strat, które mogą powstać w wyniku uwolnienia się omawianych zagrożeń.
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Small signal spectra of complex capacitance obtained on organic heterojunction formed from copper phthalocyanine and perylene dye
PublikacjaPraca przedstawia małosygnałowe widma zespolonej pojemności otrzymane na strukturze z heterozłączem organicznym CuPc/Py-PTC w zakresie 25Hz-1MHz.
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Highly Visible-Light-Photoactive Heterojunction Based on TiO2 Nanotubes Decorated by Pt Nanoparticles and Bi2S3 Quantum Dots
PublikacjaA heterojunction with excellent visible light response and stability based on titanium dioxide nanotubes (TiO2 NTs), bismuth sulfide quantum dots (Bi2S3 QDs), and platinum nanoparticles (Pt NPs) is proposed. Both Pt NPs (3.0 ± 0.2 nm) and Bi2S3 QDs (3.50 ± 0.20 nm) are well distributed on the (i) top parts, (ii) inner walls, and (iii) outer walls of the TiO2 NTs. Visible-light-induced photoreaction was initialized by excitation...
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Growth and Isolation of Large Area Boron‐Doped Nanocrystalline Diamond Sheets: A Route toward Diamond‐on‐Graphene Heterojunction
PublikacjaMany material device applications would benefit from thin diamond coatings, but current growth techniques, such as chemical vapor deposition (CVD) or atomic layer deposition require high substrate and gas‐phase temperatures that would destroy the device being coated. The development of freestanding, thin boron‐doped diamond nanosheets grown on tantalum foil substrates via microwave plasma‐assisted CVD is reported. These diamond...
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Heterojunction of (P, S) co-doped g-C3N4 and 2D TiO2 for improved carbamazepine and acetaminophen photocatalytic degradation
PublikacjaNovel photocatalysts of phosphorus and sulfur co-doped graphitic carbon nitride incorporated in 2D TiO2 structure were successfully fabricated and applied for solar-driven degradation of emerging pollutants from the group of pharmaceuticals not susceptible to biodegradation. The hybrid photocatalysts with different loadings of (P, S)-doped g-C3N4 were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),...
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A General Scheme of a Branch-and-Bound Approach for the Sensor Selection Problem in Near-Field Broadband Beamforming
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Efficient handover scheme for Mobile IPv4 over IEEE 802.11 networks with IEEE 802.21 triggers.
PublikacjaEfektywność przełączania jest bardzo istotnym parametrem, decydującym o pracy sieci bezprzewodowych, realizujacych usługi multimedialne na wysokim poziomie jakości. Użytkownicy takich sieci oczekują ciągłej obsługi podczas procesu przemieszczania się. Okazuje się, że istotnym źródlem opóźnień są nieefektywne procedury przełączania w warstwach drugiej i trzeciej, wynikający częściowo z postulatu o separacji funkcji realizowanych...
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Augmented speed control scheme of dual induction motors with mutual flux angle control loop
PublikacjaThis paper proposes an augmented speed control scheme of dual induction motors fed by a five-leg voltage source inverter (VSI) with a common/shared-leg. An additional control loop is proposed here and based on the mutual flux angle – the difference between flux angular positions of the IMs. The main purpose of this research is to minimize the energy losses in the common inverter leg by controlling the mutual flux angle, at equal...
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Modelling of the Polish Electricity Generation Subsystem in MARKAL Program with Emphasis on the EU Emissions Trading Scheme
PublikacjaThis paper addresses issues related to greenhouse gas emissions in the European Union and measures to reduce them, in particular the European Emissions Trading Scheme (EU ETS). A model of the Polish electricity generation subsystem, taking into account EU ETS mechanisms, has been developed using the MARKAL optimization package. Data collected on the basis of available projects, regulations and statistics were entered into the model....
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Single-phase, Five-level Inverter with SPWM-Based Neutral Point Voltage Balancing Scheme
PublikacjaMultilevel inverter topologies provide several advantages over two-level inverter configuration. These benefits are the reason for the growing interest in multilevel topologies among research society. One of the most popular topological concepts (diode and active switch clamping) requires neutral-point potential balancing due to series-connected capacitor banks across the input dc link in such derived inverter configurations. This...
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Fast and reliable knowledge-based design closure of antennas by means of iterative prediction-correction scheme
PublikacjaA novel framework for expedited antenna optimization with an iterative prediction-correction scheme is proposed. The methodology is comprehensively validated using three real-world antenna structures: narrow-band, dual-band and wideband, optimized under various design scenarios. The keystone of the proposed approach is to reuse designs pre-optimized for various sets of performance specifications and to encode them into metamodels...
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Testing OFDM Transmission Schemes for Shallow Water Acoustic Communications
PublikacjaLarge variability of communication properties of underwater acoustic channels, and especially strongly varying instantaneous conditions in shallow waters, is a tough challenge for the designers of underwater acoustics communication (UAC system. There is a need for developing adaptive signaling schemes that would dynamically optimize signal parameters in both physical and link layers of communication protocols. The orthogonal frequency...
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Fundamental Schemes to Determine Disjoint Paths for Multiple Failure Scenarios
PublikacjaDisjoint path routing approaches can be used to cope with multiple failure scenarios. This can be achieved using a set of k (k> 2) link- (or node-) disjoint path pairs (in single-cost and multi-cost networks). Alternatively, if Shared Risk Link Groups (SRLGs) information is available, the calculation of an SRLG-disjoint path pair (or of a set of such paths) can protect a connection against the joint failure of the set of links...
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Linking optical and electronic properties to photoresponse of heterojunctions based on titania nanotubes and chromium, molybdenum, and tungsten oxides
PublikacjaThe development of photosensitization strategies for titanium dioxide is necessary for the enhancement of its optical and electronic properties towards its application potential in solar photoelectrochemistry. In this work, significant differences in the photosensitizing capability of the 6th group transition metal oxides applied on the surface of titania nanotubes are reported. For the first time, correlations between the experimentally...
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Modulo N Backoff Scheme for effective QoS differentiation and increased bandwidth utilization in IEEE 802.11 networks
PublikacjaThe paper presents a new "modulo N" channel access scheme for wireless Local Area Networks (WLANs). The novel solution derives from the Distributed Coordination Function (DCF) of the IEEE 802.11 standard, further elaborated as Enhanced Distribution Channel Access (EDCA) by the 802.11e draft specification. The main innovation concerns improvement of the binary exponential backoff scheme used for collision avoidance in 802.11 networks....
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Multicast Traffic Throughput Maximization through Dynamic Modulation and Coding Scheme Assignment in Wireless Sensor Networks
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Combinatorial scheme of finding minimal number of periodic points for smooth self-maps of simply connected manifolds
PublikacjaLet M be a closed smooth connected and simply connected manifold of dimension m at least 3, and let r be a fixed natural number. The topological invariant D^m_r [f], defined by the authors in [Forum Math. 21 (2009), 491-509], is equal to the minimal number of r-periodic points in the smooth homotopy class of f, a given self-map of M. In this paper, we present a general combinatorial scheme of computing D^m_r [f] for arbitrary dimension...