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The aim of this study was to determine the interference errors on the composition papers of Turkish university students. While Turkish university students learning English are writing compositions, they sometimes confront difficulties related to proper word choices, grammatical structures and other aspects of the language due to the differences of these two languages. The aim of the study was, therefore, to determine inter-lingual errors on the composition papers written in English. 436 papers written by 26, intermediate level, preparatory class students (3 male, 23 female), and 642 papers written by 42 upper intermediate level students (11 male and 31 female), were examined in this study. According to the result of the study, the highest ranking interference errors of Turkish university EFL students were “word for word translation”, omitting the indefinite article, subject-verb agreement and number, quantifier and noun agreement. The study also revealed that intermediate level students committed more errors than those who were upper-intermediate and that most errors were general errors, not interference errors. And also it was clear from the present study that as the level of the students got higher, the number of the errors and interference errors got lower.

Characterizing the fundamental energy efficiency (EE) performance of multiple-input-multiple-output interfering broadcast channels (MIMO-IFBC) is important for the design of green wireless system. In this paper, we propose a new network architecture proposition based on EE maximization for Multi-Cell MIMO-IFBC within the context of interference alignment (IA). Particularly, EE is maximized subject to maximum power and minimum throughput constraints. We propose two schemes to optimize EE for different signal-to-noise ratio (SNR) regions. For high-SNR operating regions, we employ a grouping-based IA scheme to jointly cancel intra- and inter-cell interferences and thus transform the MIMO-IFBC to a single-cell MIMO scenario. A gradient-based power adaptation scheme is proposed based on water-filling power adaptation and singular value decomposition to maximize EE for each cell. For moderate SNR cases, we propose an approach using dirty paper coding (DPC) with the principle of multiple access channel and broadcast channel duality to perform IA while maximizing EE in each cell. The algorithm in its dual form is solved using a subgradient method and a bisection searching scheme. Simulation results demonstrate the superior performance of the proposed schemes over several existing approaches. It also shows that interference-nulling-based IA approaches outperform hybrid DPC-IA approach in high-SNR region, and the opposite occurs in low-SNR region.

Study results indicate that moments of unoccupied rest immediately after learning serve an essential cognitive function: memory consolidation. However, there also are findings suggesting that waking rest after learning has similar effects on delayed memory performance as an active wake condition, where participants work on a cognitive distractor task. Based on these studies, we highlight several potentially modulating factors of the so-called resting effect.

Recent findings have shown that it is possible to use the Layer-by-Layer technique to create nanofibrillated cellulose / polyethyleneimine interference films whose colour change with relative humidity. This study uses different optical models to describe spectral ellipsometry measurements data of interference films and how the film properties alter in dry and humid environments. The results indicate that water condensation initially is filling the surface pores within seconds whereas relaxation of the film to adjust to the added water is a slower process that reaches a steady state after »20 min. The maximum swelling ratio of the LbL films is almost independent of the number of layers within the film, but decreases considerably by crosslinking via heat treatment. The films show a distinct birefringence with optical axis perpendicular to the surface. Analysis of the moisture response with different optical models indicates that the films swell uniformly in the thickness direction with no separate water film on top. The results provide important understanding for the design of NFC based LbL films for visual moisture sensors and interactive security paper.

In barley (Hordeum vulgare L.), chiasmata (the physical sites of genetic crossovers) are skewed towards the distal ends of chromosomes, effectively consigning a large proportion of genes to recombination coldspots. This has the effect of limiting potential genetic variability, and of reducing the efficiency of map-based cloning and breeding approaches for this crop. Shifting the sites of recombination to more proximal chromosome regions by forward and reverse genetic means may be profitable in terms of realizing the genetic potential of the species, but is predicated upon a better understanding of the mechanisms governing the sites of these events, and upon the ability to recognize real changes in recombination patterns. The barley MutL Homologue (HvMLH3), a marker for class I interfering crossovers, has been isolated and a specific antibody has been raised. Immunolocalization of HvMLH3 along with the synaptonemal complex transverse filament protein ZYP1, used in conjunction with fluorescence in situ hybridization (FISH) tagging of specific barley chromosomes, has enabled access to the physical recombination landscape of the barley cultivars Morex and Bowman. Consistent distal localization of HvMLH3 foci throughout the genome, and similar patterns of HvMLH3 foci within bivalents 2H and 3H have been observed. A difference in total numbers of HvMLH3 foci between these two cultivars has been quantified, which is interpreted as representing genotypic variation in class I crossover frequency. Discrepancies between the frequencies of HvMLH3 foci and crossover frequencies derived from linkage analysis point to the existence of at least two crossover pathways in barley. It is also shown that interference of HvMLH3 foci is relatively weak compared with other plant species.

The males of many pierid butterflies have iridescent wings, which presumably function in intraspecific communication. The iridescence is due to nanostructured ridges of the cover scales. We have studied the iridescence in the males of a few members of Coliadinae, Gonepteryx aspasia, G. cleopatra, G. rhamni, and Colias croceus, and in two members of the Colotis group, Hebomoia glaucippe and Colotis regina. Imaging scatterometry demonstrated that the pigmentary colouration is diffuse whereas the structural colouration creates a directional, line-shaped far-field radiation pattern. Angle-dependent reflectance measurements demonstrated that the directional iridescence distinctly varies among closely related species. The species-dependent scale curvature determines the spatial properties of the wing iridescence. Narrow beam illumination of flat scales results in a narrow far-field iridescence pattern, but curved scales produce broadened patterns. The restricted spatial visibility of iridescence presumably plays a role in intraspecific signalling. Electronic supplementary material The online version of this article (doi:10.1007/s00359-011-0661-6) contains supplementary material, which is available to authorized users.

CRISPR-Cas systems are RNA-guided immune systems that protect prokaryotes against viruses and other invaders. The CRISPR locus encodes crRNAs that recognize invading nucleic acid sequences and trigger silencing by the associated Cas proteins. There are multiple CRISPR-Cas systems with distinct compositions and mechanistic processes. Thermococcus kodakarensis (Tko) is a hyperthermophilic euryarchaeon that has both a Type I-A Csa and a Type I-B Cst CRISPR-Cas system. We have analyzed the expression and composition of crRNAs from the three CRISPRs in Tko by RNA deep sequencing and northern analysis. Our results indicate that crRNAs associated with these two CRISPR-Cas systems include an 8-nucleotide conserved sequence tag at the 5' end. We challenged Tko with plasmid invaders containing sequences targeted by endogenous crRNAs and observed active CRISPR-Cas-mediated silencing. Plasmid silencing was dependent on complementarity with a crRNA as well as on a sequence element found immediately adjacent to the crRNA recognition site in the target termed the PAM (protospacer adjacent motif). Silencing occurred independently of the orientation of the target sequence in the plasmid, and appears to occur at the DNA level, presumably via DNA degradation. In addition, we have directed silencing of an invader plasmid by genetically engineering the chromosomal CRISPR locus to express customized crRNAs directed against the plasmid. Our results support CRISPR engineering as a feasible approach to develop prokaryotic strains that are resistant to infection for use in industry.

In this paper, we consider the problem of power control for a wireless network with an arbitrarily time-varying topology, including the possible addition or removal of nodes. A data-driven design methodology that leverages graph neural networks (GNNs) is adopted in order to efficiently parametrize the power control policy mapping the channel state information (CSI) to transmit powers. The specific GNN architecture, known as random edge GNN (REGNN), defines a non-linear graph convolutional filter whose spatial weights are tied to the channel coefficients. While prior work assumed a joint training approach whereby the REGNN-based policy is shared across all topologies, this paper targets adaptation of the power control policy based on limited CSI data regarding the current topology. To this end, we propose a novel modular meta-learning technique that enables the efficient optimization of module assignment. While black-box meta-learning optimizes a general-purpose adaptation procedure via (stochastic) gradient descent, modular meta-learning finds a set of reusable modules that can form components of a solution for any new network topology. Numerical results validate the benefits of meta-learning for power control problems over joint training schemes, and demonstrate the advantages of modular meta-learning when data availability is extremely limited., Comment: Submitted for publication

Funding Information: The first author thanks the Finnish Work Environment Fund (No. 200224) for supporting this research. The second author sincerely thanks Prof. Charles D. Bailey of James Madison University for making his data available. Without it, this study would not have been possible. He also conveys his thanks to the Social Sciences and Humanities Research Council (SSHRC) of the Canada-Insight Grant Program (No. 435-2020-0628) for supporting this research. Funding Information: The first author thanks the Finnish Work Environment Fund (No. 200224 ) for supporting this research. The second author sincerely thanks Prof. Charles D. Bailey of James Madison University for making his data available. Without it, this study would not have been possible. He also conveys his thanks to the Social Sciences and Humanities Research Council (SSHRC) of the Canada-Insight Grant Program (No. 435-2020-0628 ) for supporting this research. Publisher Copyright: © 2021 Production and operations management (POM) uses learning curve (LC) models to determine the length of training sessions for new workers and predicting future task performance. Empirically validated LC parameters provide managers with quantitative information on the effects of the presumed factors behind the learning process. Previous studies considered LC to compose of cognitive and motor curves. Another widely acknowledged but only recently parameterized phenomenon in the POM field is interference, which assumes some loss of information or experience could occur over a learning session. This paper takes a logical step in this line of research by developing an interference-adjusted power LC model, a composite of cognitive and motor elements. This paper accounts for the decay of cognitive and motor memory traces from repetitions to measure the residual (interference-adjusted) experience and capture these phenomena. Three variants of the model are developed that assume power and exponential decay functions and an approximate version of the exponential one. Assembly data representing various forms of an individual learning profile have been used to test the fits of the developed models. In addition to those models, four potential models from the literature were selected for comparison purposes. The results show that the approximate model fits very well exponential learning profile. The findings highlight the confluence of the three phenomena in learning, component (cognitive/motor) learning, interference, and plateauing. (c) 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

This paper presents an on-line monitoring method of IGBT module bond wires aging based on the phase-frequency characteristics (PFCs) of differential mode (DM) interference signal. Firstly, the collector current variation during IGBT chip switching is analyzed, and the relationship between the aging degree of bond wires and the PFCs of DM interference signal is studied; Secondly, a phase angle characteristic measurement system of DM interference signal is built and used to online monitor the aging of bond wires in IGBT module; Finally, taking the buck converter composed of IGBT module as the equipment under tested, the interference signal is extracted by the RF current probe and processed by the low-pass filter and signal amplifier, then the phase angle characteristics are measured by the oscilloscope board to realize the on-line monitoring of the bond wires aging of IGBT module. The experimental results show that compared with buck converter with healthy IGBT module, the phase angle of DM interference signal in Buck Converter with aging IGBT module is reduced. The proposed method does not need expensive equipment such as spectrum analyzer, and only needs to monitor the aging state of bond wires in IGBT module online through oscilloscope board. Besides, the research method in this paper provides an approximate linear monitoring method for bonding wire lift-off.

To boost large-scale deployment of unmanned aerial vehicles (UAVs) in the future, a new wireless communication paradigm namely cellular-connected UAVs has recently received an upsurge of interest in both academia and industry. Fifth generation (5G) networks are expected to support this large-scale deployment with high reliability and low latency. Due to the high mobility, speed, and altitude of the UAVs there are numerous challenges that hinder its integration with the 5G architecture. Interference is one of the major roadblocks to ensuring the efficient co-existence between UAVs and terrestrial users in 5G networks. Conventional interference mitigation schemes for terrestrial networks are insufficient to deal with the more severe air-ground interference, which thus motivates this paper to propose a new algorithm to mitigate interference. A deep Q-learning (DQL) based algorithm is developed to mitigate interference intelligently through power control. The proposed algorithm formulates a non-convex optimization problem to maximize the Signal to Interference and Noise Ratio (SINR) and solves it using DQL. Its performance is measured as effective SINR against the complement cumulative distribution function. Further, it is compared with an adaptive link technique: Fixed Power Allocation (FPA), a standard power control scheme and tabular Q-learning(TQL). It is seen that the FPA has the worst performance while the TQL performs slightly better. This is since power control and interference coordination are introduced but not as effectively in the TQL method. It is observed that DQL algorithm outperforms the TQL implementation. To solve the severe air-ground interference experienced by the UAVs in 5G networks, this paper proposes a DQL algorithm. The algorithm effectively mitigates interference by optimizing SINR of the air-ground link and outperforms the existing methods. This paper therefore, proposes an effective algorithm to resolve the interference challenge in air-ground links for 5G-connected UAVs.

This paper investigates the degradation caused by interference resulting from cyclic prefix violation and symbol timing offset in narrowband power line communication systems. In this sense, it presents a unified formulation from which Hermitian symmetric orthogonal frequency division multiplexing (HS-OFDM), orthogonal chirp division multiplexing (OCDM), single-carrier cyclic prefix (SCCP), and orthogonal time–frequency division multiplexing (OTFDM) can be easily derived. The paper then provides closed-form expressions for quantifying the aforementioned interference in the presence of a frequency domain equalizer. The numerical analyses exhibit the performances of these schemes under various data communication conditions, such as the availability of channel state information, the presence or absence of interference, modeling of additive noise as a white or colored Gaussian random process, frequency domain equalizer type, and the use of bit and power allocation techniques. The closed-form expressions and performance analyses regarding achievable data rate and bit error probability provide guidance for dealing with distinct constraints in narrowband power line communication (PLC) systems using the HS-OFDM, OCDM, SCCP, or OTFDM scheme. Lastly, the unified formulation and results obtained motivate the design of multi-scheme transceivers.

In this paper, practical and conceptual problems related to the way of suppressing or eliminating the influence of interference (at a frequency of 50 Hz) in an active high-voltage power facility are discussed. The problem is relevant in the context of measuring the safety characteristics of the grounding system: grounding system impedance, touch voltage and step voltage. The paper gives an evolutionary overview of title methods. The review focuses on the characteristic problems and shortcomings of individual methods. Also, the basic characteristics of the author's FSM (Frequency Shift Method) method, which guarantees precise control of interference, are elaborated. In this sense, the FSM method is the basis for accurate and economical measurement of the safety characteristics of the grounding system.

Проблематика. Через велику кількість аварій на дорогах автомобільний зв'язок стає предметом уваги багатьох дослідників. Тому безпека водіння є головною турботою багатьох дослідників, щоб пом'якшити проблеми заторів, особливо за міським сценарієм. У зв'язку з вимогою URLLC, в цій статті ми досліджуємо важливість зменшення потужності. Фактично, мінімізація потужності є цікавою метрикою через вимоги високої швидкості передачі даних. Мета дослідження. Метою даної роботи є дослідження розподілу потужності в системі LTE-V за децентралізованим сценарієм. Методика реалізації. Ідея полягає в тому, щоб розглянути групу з набором транспортних засобів, що взаємодіють один з одним для мережевих ресурсів без допомоги ENodeB. Мінімізація енергоспоживання є багатообіцяючим рішенням для зменшення перешкод, оскільки транспортні засоби взаємодіють децентралізовано. В цьому відношенні теоретичний аналіз заснований на застосуванні ігровий політики Stackelberg для управління потужністю таким чином, щоб мінімізувати перешкоди. Результати досліджень. Ігрова політика Stackelberg є потужним інструментом для управління перешкодами і енергоспоживанням. Комп'ютерні результати підкреслюють ефективність гри SK для розподілу потужності в децентралізованому сценарії. Висновки. Автономний автомобільний зв'язок привернув увагу багатьох дослідників у зв'язку зі збільшенням кількості заторів і проблемами з дорожнім рухом. Зв'язок між авто - цікава тема пошуку, щоб забезпечити задовільну обставноку на дорогах. Крім того, група має потенціал для забезпечення безпеки при низькому енергоспоживанні, особливо в міських умовах. Крім того, LTE-V являє собою евристичне рішення для автомобільної зв'язку, де підключення здійснюється в децентралізованому контексті без вимоги ENodeB. Background. Due to the great increase of accident into roads, vehicular communication becomes the focus of many researchers. Therefore vehicular communication is becoming an active topic of search. That’s why safety driving is the main concern of many researcher to mitigate congestion problems specifically following urban scenario. Due to the requirement of URLLC, we investigate in this paper the importance of power diminishing. In fact, power minimization is an interesting metric due to the requirement of high data rates. Objective. The aim of the paper is to investigate power allocation into LTE-V system following a decentralized scenario. Methods. The idea is to consider a platoon with a set of vehicles interacting together for network resources without the help of ENodeB. Power consumption minimization is a promising solution for interference diminishing since vehicles communicate according to a decentralized way. In this regard the theoretical analysis is based on applying stackelberg game policy for power control in the way to minimize interference. Results. We conclude that stackelberg game policy is a powerful tool for interference and power consumption management. Computer results highlight the efficiency of SK game for power allocation into a decentralized scenario. Conclusions. Vehicular Autonomous communication attracted the attention of many researchers according to increasing number of congestion together with traffic problems. In addition, to ensure better safety we adopt platooning scenario which enables mitigations of many problems such as collisions, congestion. Inter-car communication is an interesting topic of search to ensure safety into-roads. In addition, platooning has the potential to ensure safety with low energy consumption specifically towards urban traffic. In addition, LTE-V is a heuristic solution for vehicular communication where the connectivity is performed in a decentralized context without the requirement of the ENodeB. Проблематика. Из-за большого количества аварий на дорогах автомобильная связь становится предметом внимания многих исследователей. Поэтому автомобильная связь становится активной темой поиска. В силу этих обстоятельств безопасность вождения является главной заботой многих исследователей, чтобы смягчить проблемы заторов, особенно по городскому сценарию. В связи с требованием URLLC, в этой статье мы исследуем важность уменьшения мощности. Фактически, минимизация мощности является интересной метрикой из-за требования высокой скорости передачи данных. Цель исследований. Целью данной работы является исследование распределения мощности в системе LTE-V по децентрализованному сценарию. Методика реализации. Идея состоит в том, чтобы рассмотреть группу с набором транспортных средств, взаимодействующих друг с другом для сетевых ресурсов без помощи ENodeB. Минимизация энергопотребления является многообещающим решением для уменьшения помех, поскольку транспортные средства взаимодействуют децентрализованно. В этом отношении теоретический анализ основан на применении игровой политики Stackelberg для управления мощностью таким образом, чтобы минимизировать помехи. Результаты исследований. Игровая политика Stackelberg является мощным инструментом для управления помехами и энергопотреблением. Компьютерные результаты подчеркивают эффективность игры SK для распределения мощности в децентрализованном сценарии. Выводы. Автономная автомобильная связь привлекла внимание многих исследователей в связи с увеличением количества заторов и проблемами с дорожным движением. Межавтомобильная связь - интересная тема поиска, чтобы обеспечить удовлетворительную обставноку на дорогах. Кроме того, группа имеет потенциал для обеспечения безопасности при низком энергопотреблении, особенно в городских условиях. Кроме того, LTE-V представляет собой эвристическое решение для автомобильной связи, где подключение осуществляется в децентрализованном контексте без требования ENodeB.

In this paper, we investigate the uplink transmission performance of low-power wide-area (LPWA) networks with regards to coexisting radio modules. We adopt long range (LoRa) radio technique as an example of the network of focus even though our analysis can be easily extended to other situations. We exploit a new topology to model the network, where the node locations of LoRa follow a Poisson cluster process (PCP) while other coexisting radio modules follow a Poisson point process (PPP). Unlike most of the performance analysis based on stochastic geometry, we take noise into consideration. More specifically, two models, with a fixed and a random number of active LoRa nodes in each cluster, respectively, are considered. To obtain insights, both the exact and simple approximated expressions for coverage probability are derived. Based on them, area spectral efficiency and energy efficiency are obtained. From our analysis, we show how the performance of LPWA networks can be enhanced through adjusting the density of LoRa nodes around each LoRa receiver. Moreover, the simulation results unveil that the optimal number of active LoRa nodes in each cluster exists to maximize the area spectral efficiency., Comment: This paper has been accepted by IEEE Trans. Vehicular Technology (TVT)

International audience; Hybrid broadcast/broadband network (HBBN) presents a potential solution to mitigate the increasing demand for mobile TV. A proper HBBN deployment alleviates the limitations that each standalone network faces, thereby enhancing the global network coverage and efficiency. In this paper, we propose to address the question of performance improvement expected from such HBBN by means of an analytical framework based on stochastic geometry modeling. To this end, we introduce a generic model of the HBBN where multiple broadcast transmitters and a broadband network are deployed in the same area, jointly offering linear services, one of the mobile TV services. Two different approaches derived from stochastic geometry are applied and compared through the analysis of what is commonly referred to as a Point Hole Process (PHP) Original Poisson Point Process (PPP), and reduced PPP. Both approaches are thoroughly analyzed to give better insights into broadcast/broadband coexistence while taking into account the inter-cell interference of both networks. Exact and simplified expressions for the key performance metrics are derived such as the probability of coverage and ergodic capacity. Those expressions are then used to numerically maximize the spectral and power efficiency of the HBBN regarding the broadcast coverage radius and transmitters density. The results show that for a wide range of user density, the HBBN introduces gain compared to either BB or BC networks. To the best of the authors knowledge, this paper presents the first work dealing with the optimization of HBBN based on such a generic model and taking inter-cell and inter-network interference into consideration.

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GNSS is widely used to provide positions in an absolute reference frame in Unmanned Aerial Vehicles (UAV) and Unmanned Ground Vehicles (UGV), where GNSS is merged with the information provided by other sensors. Even if the main goal of GNSS signal processing is the positioning, multifrequency signals are a rich source of information about the propagation environment surrounding the mobile vehicle. In urban and harsh environment, situational awareness is essential to tailor the operations and take proper countermeasure to harsh propagation conditions. Given this framework the present paper will describe the use of GNSS as signals of opportunity for the characterization of the operative environment by processing the GNSS observables through Machine Learning (ML) algorithms that can be used as efficient features extractors. The paper will present some case studies of operational scenarios for UGVs and for a static monitoring station, showing how through combining DSP techniques with both unsupervised and supervised ML algorithms (K-means classes, Support Vector Machines) it is possible to retrieve the information about the propagation scenario for multipath, interference and atmospheric limitations.

This paper is devoted to the problem of learning Russian by native speakers of the Polish language. The presented research is made in the context of the language-oriented approach and includes linguistic experiment, comparative analysis of Russian and Polish languages and identification of problem areas causing interference errors. A system of rules and exercises for Polish learners of Russian is being proposed as a recommended practice for excluding interference errors. The language-oriented approach used in this report is based, first, on provisions that take into account the already existing initial language system of learners, second, on a comparative analysis of languages, and third, on an analysis of learners’ mistakes. Mastering a foreign language takes place in close interaction with language systems in the minds of students. In the situation of interaction between two contacting languages, interference is likely to occur. Identification of interference errors in the analysis of speech of foreign languages allows us to identify problem areas in the studied language and correct the language skill in the course of learning. Typical mistakes are material for creating the necessary strategy of teaching the Russian language for native speakers of a certain language. The paper is based on the master's thesis "The project of a language-oriented guidebook on the Russian language for native speakers of the Polish language". The thesis was successfully defended (5) on June 27, 2019 at Irkutsk State University.

The emergence of connected automated vehicles and advanced V2X applications and services can challenge the scalability of vehicular networks in the future. This challenge requires solutions to reduce and control the communication channel load beyond the traditional congestion control protocols proposed to date. In this paper, we propose and evaluate the use of V2X message compression to reduce the channel load and improve the scalability and reliability of future vehicular networks. Data compression has the potential to reduce the channel load consumed by each vehicle without reducing the amount of information transmitted. To analyze its potential, this paper evaluates the compression gain of three compression algorithms using standardized V2X messages for basic awareness (CAMs), cooperative perception (CPMs) and maneuver coordination (MCMs) extracted from standard-compliant prototypes. We demonstrate through network simulations that V2X message compression can reduce the channel load. In particular, the tested compression algorithms can reduce the channel load by up to 27% without reducing the amount of information transmitted. Reducing the channel load and the consequent interferences significantly improves the reliability of V2X communications. However, this study also emphasizes the need for high-speed compression and decompression modules capable to compress and decompress V2X messages in real time, especially under highly loaded scenarios.

The paper presents the results of testing the electric and magnetic fields across a wide frequency spectrum as unintentionally generated in an extensive railway area. High levels of electromagnetic interference generated in a railway area can cause the malfunction of electrical and electronic devices. The paper presents an electromagnetic environment in the low and high frequency spectra that prevail in an extensive railway area. Special attention was paid to the impact of electromagnetic interference on specific electronic systems. Keywords: electromagnetic field, spectrum, interference, induction and capacitive coupling

The focus of this paper is on evaluating different spatial interpolation methods for the construction of radio environment map (REM) using field measurements obtained by cyclostationary based mobile sensors. Mobile sensing devices employing cyclostationary detectors provide lot of advantages compared to widely used energy detectors such as robustness to noise uncertainty and ability to distinguish among different primary user signals. However, mobile sensing results are not available at locations between the sensors making it difficult for a secondary user (possibly without a spectrum sensor) to decide whether or not to use primary user resources at that location. To overcome this, spatial interpolation of test statistics measured at limited number of locations can be carried out to create a channel occupancy map at unmeasured locations between the sensors. For this purpose, different spatial interpolation techniques for the cyclostationary test statistic have been employed in this paper such as inverse distance weighting (IDW), ordinary Kriging (OK), and universal Kriging (UK). The effectiveness of these methods is demonstrated by applying them on extensive real-world field measurement data obtained by mobile-phone-compliant spectrum sensors. The field measurements were carried out using four mobile spectrum sensors measuring eight DVB-T channels at more than hundred locations encompassing roughly one-third of the area of the city of Espoo in Finland. The accuracy of the spatial interpolation results based on the field measurements is determined using the cross validation approach with the widely used root mean square error (RMSE) as the metric. Field measurement results indicate that reliable results with spatial coverage can be achieved using Kriging for cyclostationary based test statistics. Comparison of spatial interpolation results of cyclostationary test statistics is also carried out with those of energy values obtained during the measurement campaign in the form of received signal strength indicator (RSSI). Comparison results clearly show the performance improvement and robustness obtained by the use of cyclostationary based detectors instead of energy detectors. acceptedVersion

Ultra-dense small cell deployment in future 5G networks is a promising solution to the ever increasing demand of capacity and coverage. However, this deployment can lead to severe interference and high number of handovers, which in turn cause increased signaling overhead. In order to ensure service continuity for mobile users, minimize the number of unnecessary handovers and reduce the signaling overhead in heterogeneous networks, it is important to model adequately the handover decision problem. In this paper, we model the handover decision based on the multiple attribute decision making method, namely Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The base stations are considered as alternatives, and the handover metrics are considered as attributes to selecting the proper base station for handover. In this paper, we propose two modified TOPSIS methods for the purpose of handover management in the heterogeneous network. The first method incorporates the entropy weighting technique for handover metrics weighting. The second proposed method uses a standard deviation weighting technique to score the importance of each handover metric. Simulation results reveal that the proposed methods outperformed the existing methods by reducing the number of frequent handovers and radio link failures, in addition to enhancing the achieved mean user throughput.

The universal filtered multi-carrier (UFMC) has been taken as a promising candidate for future wireless communication, where a finite impulse response filter is employed to shape the waveform and enhance its resistance to inter-carrier interference. In previous studies, the Dolph–Chebyshev filter had been used due to its low-sidelobe levels, but at the cost of low flexibility to filter the performance control. Hence, this paper puts forward an effective scheme to design an anti-interference filter for UFMC system, where the Nyquist condition (or sampling inter-symbol interference equivalently), the in-band distortion, and the out-of-band emission are taken into consideration. First, this paper models the filter design as a constrained minimax optimization concerning above-mentioned filter performance indexes. Then, the original nonconvex constraints on Nyquist condition are approximately transformed to a linear matrix inequation and two linear inequations. Finally, the optimization problem is solved by semi-definite programming. The numerical examples explicitly demonstrate the flexible performance tradeoff of the proposed method, in which the included filter performance indexes can be effectively controlled. Moreover, the bit-error-rate (BER) tests of the UFMC system confirms the effectiveness of our study, where the designed filters show BER advantages over filters of the previous literature. Therefore, the proposed waveform shaping filters can benefit variant applications of UFMC for its flexible performance tradeoffs as well as the improved anti-interference performance.

This paper examines the use of English articles and some determiners in English as second language (ESL) with a view to establish the differences between ESL and native English use of determiners and the sociolinguistic factors that inform their use. Examples were drawn from Educated Nigerian English (ENE) and Standard British English (SBE). The paper is based on the concepts of linguistic interference and intraference. Observation and recording of spontaneous speeches, secondary sources, the Internet and questionnaire were used to gather data from 2005 to 2014 across Nigeria to establish how determiners are deployed and the currency and ubiquity of the patterns observed in ENE. The responses to the questionnaire and interviews were analyzed and presented in simple percentile, frequency tables and charts, and discussed thereafter. The study discovered that there are clear differences in the patterns of the use of articles in ESL, as the ENE examples show. As a result of interference and intraference, educated Nigerians tend to overgeneralize the use of articles and determiners with noun phrases, applying them superfluously or omitting them where necessary and even sometimes using the as a possessive determiner for his, her and their. They also often yoke similar and exclusive determiners together in nominal structures. The paper concludes that these patterns should be treated as some of the features that characterize Nigerian English syntax.

The ever-increasing demand for mobile Internet and high-data-rate applications poses unique challenging requirements for 5G mobile networks, including spectrum limitations and massive connectivity. Cognitive radio and carrier aggregation (CA) have recently been proposed as promising technologies to overcome these challenges. In this paper, we investigate joint relay selection and optimal power allocation in an underlay cooperative cognitive radio with CA, taking into account the availability of multiple carrier components in two frequency bands, subject to outage probability requirements for primary users (PUs). The secondary user network employs relay selection, where the relay that maximizes the end-to-end sum rate is selected, assuming both decode-and-forward and amplify-and-forward relaying. The resulting optimization problems are optimally solved using convex optimization tools, i.e., dual decomposition and an efficient iterative method, allowing their application in practical implementations. Simulation results illustrate that the proposed configuration exploits the available degrees of freedom efficiently to maximize the SU rate, while meeting the PU average outage probability constraints. 1 1967-2012 IEEE. Manuscript received May 27, 2016; revised October 2, 2016; accepted November 7, 2016. Date of publication December 2, 2016; date of current version July 14, 2017. The work of P. D. Diamantoulakis, G. K. Karagiannidis, and T. Khattab was supported by the NPRP under Grant NPRP 6-1326-2-532 from the Qatar National Research Fund (a member of Qatar Foundation). This work was presented in part at the IEEE Wireless Communications and Networking Conference (WCNC), Doha, Qatar, Apr. 2016. The review of this paper was coordinated by Prof. D. B. da Costa. Scopus

Due to development of different technologies there has been significant improvement in quality of life. As a result of that, average person’s lifetime duration has been increased. That triggers the problem of independent living of senior citizens. One of the main concerns of the world today is how to enable senior citizens to live independently. As a response to that, systems like eWALL are being developed. eWALL for Active Long Living is a FP7 funded project and it aims to develop system which will enable elderly people to live independently. These systems consist of a large number of sensors which make wireless sensor network. In this paper, different wireless technologies that can be used for communication in systems that are designed to support independent living of elderly people, have been described. The most important focus is at wireless personal area network technologies, like ZigBee, Bluetooth, Bluetooth Low Energy and wireless local area network technologies (e.g., Wi-Fi). There are many obstacles in designing wireless sensor network and most of them concern energy efficiency and interoperability of different technologies that are being used for communication. The main challenge in the current technology world is tremendous increase of use of various wireless devices and technologies, which can cause relatively high interference, so that the wireless devices can stop working. Using cognitive radio in solving the interoperability problem of different wireless technologies in wireless sensor networks has become interesting research topic. In this paper, research on interoperability of different wireless technologies is presented. Using Spectrum Engineering Advanced Monte Carlo Analysis Tool wireless sensors network in home environment was modelled. Interference based on devices layout and activity was investigated. Also, possible improvements that can be made with cognitive radio are investigated and obtained results are given in this paper.

Foraging trails of leaf-cutting ants may be exposed to plant material that interferes with foragers’ flux either by physically blocking it or due to secondary metabolites which affect insect behavior. We hypothesized that plant secondary metabolites such as plant volatiles may interfere with pheromone communication, triggering clearing behavior. We impregnated small pieces of paper with different plant odors from native and exotic species and placed them in the middle of foraging trails of the leaf-cutting ant Acromyrmex lobicornis. As a control, we used papers impregnated with trail odor. The paper used as substrate for the odors did not constitute a physical obstacle based on its small surface area. Papers treated with trail odor did not interfere with ant flux and were not removed from the trail. However, when papers were treated with plant odors, they were removed from the trail in most of the cases and ant flux was reduced significantly by 15–28%. We found that ants tapped the tip of their gaster against the ground around the treated papers only when they were impregnated with foreign odors. The number of gaster tappings as well as the time between the placement of the paper and its removal increased with plant odor concentration. However, the decision to remove the paper was not correlated with the number of gaster tappings. Interestingly, clearer ants were smaller than forager ants, suggesting there is morphological differentiation in clearing behavior of the trail. Results from the current study also suggest that odors trigger clearing behavior on foraging trails and affect trail marking behavior. Our results provide information about the potential for plant compounds to constitute obstacles, even when they do not physically obstruct the trail. We conclude that odors may trigger clearing behavior by interfering with pheromone communication. Fil: Alma, Andrea Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Buteler, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

openaire: EC/H2020/722424/EU//SECRET To satisfy the high data demands in future cellular networks, an ultra-densification approach is introduced to shrink the coverage of base station (BS) and improve the frequency reuse. The gain in capacity is expected but at the expense of increased interference, frequent handovers (HOs), increased HO failure (HOF) rates, increased HO delays, increase in ping pong rate, high energy consumption, increased overheads due to frequent HO, high packet losses and bad user experience mostly in high-speed user equipment (UE) scenarios. This paper presents the general concepts of radio access mobility in cellular networks with possible challenges and current research focus. In this article, we provide an overview of HO management in long-term evolution (LTE) and 5G new radio (NR) to highlight the main differences in basic HO scenarios. A detailed literature survey on radio access mobility in LTE, heterogeneous networks (HetNets) and NR is provided. In addition, this paper suggests HO management challenges and enhancingtechniques with a discussion on the key points that need to be considered in formulating an efficient HO scheme.

В статье рассматривается саундинсталляция, как одна из форм пластического искусства в контексте современного визуального искусства. Автор делает упор на произведения инсталляционного искусств, в которых художники, работающие со звуком, либо подкрепляют свои инсталляционные работы визуальным рядом, либо создают для потенциальных зрителей звуковую среду, где каждый может представить себе тот или иной визуальный ряд. Подобный метод можно отнести к явлениям синестезии и авто-кураторства, которые используются при взаимодействии зрителей с подобного рода работами. Акцент делается на репрезентацию саундинсталляции как произведения искусства, имеющего своеобразную пластическую форму. В статье описаны и проанализированы работы таких авторов как: Джон Кейдж, Нам Джун Пайк, Неманья Цвиянович, Таус Махачева, Юнес БабаАли, Сергей Филатов, Крис Коул., The given article describes sound installation as one of the forms of sculptural art in the context of contemporary visual art. The author pays attention to those pieces where artists who work with sound either enforce their installation works with some visual material or create pieces with no visual images, so the possible audiences could imagine them on their own. This method shows the use synaesthesia and auto-curation phenomena which can be used during the interference of the audiences with such pieces of art. Representation of sound installations as a piece of art that has sculptural origin is the important part of the paper because the aesthetics of the described artists implies that. Also, the paper describes and analyzes works of artists like John Cage, Nam June Paik, Nemanja Cvijanović, Taus Makhacheva, Younes Baba-Ali, Sergey Filatov, Crys Cole.

Power grids depend more and more on satellite-derived time and use signals from Global Navigation Satellite Systems (GNSSs) to be more efficient. GNSS signals serve to reference measurements to an absolute time scale, allowing for a better accuracy of the power grid state estimate. Phase Measurement Units (PMUs) take synchronous snapshots of current and voltage amplitudes/phases across the grid, returning a complete picture of the state of the power system at any time instant. Unfortunately, using conventional receiving hardware, GNSS signals transmitted by the satellites are well below the electromagnetic noise floor and are susceptible to interfering signals. Among all types of interference, intentional radio attacks (spoofing attacks) with the intent of disrupting GNSS services are becoming a significant concern, although no real incidents of this type have been publicly reported yet for power grids. This paper focuses on the threat posed by GNSS spoofing to PMUs. First, the paper critically discusses the vulnerability of some GNSS receivers, representative of those currently embedded in commercial PMUs. The relevance of the work consists in the methodology used to conduct the investigation. In fact, whereas spoofing effects on the computed positions have been reported in many papers, far less attention has been devoted to the computed time information and related applications. The paper intends to increase awareness, proving another fundamental aspect: the counterfeit signals leave clues in the receivers’ observables, thus giving the chance of transforming a feared vulnerability into a potential resilience, if these clues are detected and smartly exploited. Finally, the paper introduces the concept of authenticated civilian GNSS signals, namely the Galileo Open Service Navigation Message Authentication (OS NMA), which will be broadcast for signal experimentation starting from 2019.

Bluetooth Low Energy (BLE) is a popular wireless communication protocol heavily used in Internet of Things applications. Nowadays, robustness is considered a key requirement in wireless communication. However, radio interference from various sources may affect the performance of BLE devices, leading to channel congestion. Therefore, there is a broadly recognized need of methodologies capable of sensing and avoiding interference. In this paper, two improvements at the data link layer for interference detection and channel selection are proposed to enhance the BLE connection robustness. This paper also presents a wide range of experimental evaluations aiming at validating the improvements and providing insights on both these improvements. Particularly, the communication performance of the BLE link layer is assessed in terms of channel usage distribution, supervision timeout ratio (STR) and packet loss rate (PLR) under different interference environments. Results from these experiments (reliability over 97% and 99% under two different harsh environments) highlight the effects of both improvements on the BLE robustness. Meanwhile, the authority of scheduling the whole mechanism is given to the link layer and even the higher application layer. This paper provides a set of solutions for BLE confronting interference in link layer. ispartof: Sensors vol:21 issue:7 ispartof: location:Switzerland status: published

This paper presents an overview of the coding aspects of a GNSS receiver. Coding allows detection and correction of channel-induced errors at the receiver, here the focus is on the mitigation of threats from malicious interferences. Although the effects of interference at different stages of GNSS baseband processing has been deeply analyzed in the literature, little attention was devoted to its impact on the navigation message decoding stage. Theis paper provides an introduction to the various coding schemes employed by current GNSS signals, discussing their performance in the presence of noise in terms of block-error rate. Additionally, the benefits of soft-decoding schemes for navigation message decoding are highlighted when jamming interferences are present. The proposed scheme requires estimating the noise plus interference power, yielding to enhanced decoding performances under severe jamming conditions. Finally, cryptographic schemes as a means of providing anti-spoofing for geosecurity location-based services, and their potential vulnerability are discussed, with particular emphasis on the dependence on the dependence of the scheme on successful navigation message decoding.

Energy efficiency is one of the main system resources that has to be optimally allocated, due to its impact on the amount of generated interference and the battery life for multimedia communication. In this paper, we concentrate on the time-division duplexing (TDD) option and how to efficiently allocate energy on both uplink (UL) and downlink (DL) channels that share the same bandwidth but over different time intervals. One of the main advantages of TDD is the possibility for load compensation between UL and DL, by allocating a larger percentage of time for the operation in DL if the system is congested in DL, and vice versa. While this allocation can be done on each cell independently, the result is that adjacent cells would have a different compensation value, thus generating cross interference, which decreases the system performance, mainly on the cell-edge users. This paper presents an energy allocation in order to compensate the unsynchronization in the percentage allocation, where the objective is to guarantee minimum quality of service satisfaction at all receivers, while the least amount of energy is consumed. 2007-2012 IEEE. This work was supported in part by the research projects AGAUR (2014 SGR 1551), CellFive (TEC2014-60130-P), and QUUG-CENG-EE-14\15-8 Scopus

The paper focuses on the phenomenon of forgetting as a primal and generally productive memory process. The cases that require temporary and permanent forgetting of the data stored in the long-term memory are contrasted. The main methodological obstacle in forgetting research is identified as arising from the logical prohibition to argument from the negative, i.e. “the evidence of absence is not the evidence of absence”. Two mechanisms of forgetting are discussed in the paper: transformation of the memory trace and modulation of trace accessibility. The former mechanism of forgetting consists of memory trace destruction (memory trace decay, retroactive and proactive interference, and «catastrophic» interference) or its transformation that leads to forming a new memory representation. The most promising way to legitimize the trace destruction mechanism is narrowing the further research to episodic memory subsystem. The latter mechanism of forgetting consists of both passive failure in access to appropriate memory content (the tip of the tongue phenomenon, the category size effect, the fan effect) and the process of active retrieval inhibition. This phenomenon represents temporary inhibition of competing semantically similar responses in semantic memory, and motivational inhibition of self-deprecating memories in autobiographical memory. Thus, a variety of experimental paradigms in intentional forgetting research are considered. Contrary to the common claim that forgetting is а universal and homogeneous phenomenon, we propose that forgetting strategies might vary in different memory subsystems, and also depend on activity characteristics during encoding, storage and retrieval.

This paper focuses on how to avoid RF interference when deploying WiFi and IEEE 802.15.4/ZigBee radios simultaneously or in close proximity in indoor environments. The circumstances are particularly unfavorable for ZigBee networks that share the 2.4 GHz ISM band with WiFi senders capable of 10 to 100 times higher transmission power. However, the nature of ZigBee devices is to transmit small amount of data infrequently. Thus, we propose a solution for minimizing interference from WiFi, while limits ZigBee's occupancy rate. Another important point to be considered in this paper is that packet reception ratio (PRR) varies with the shape of crossing corridors. In general, there are typical shapes of’L’,’T’, and’+’ depending on crossing corridors. Thus, a mobile ad-hoc network topology must be configured to transmit wireless packets via intermediate nodes. The method to be proposed in this paper to avoid interference is the use of channel hopping. This channel hopping occurs by evaluating of two values on receiver node: the latest received signal strength (RSS) values and the received acknowledged packets (ACK). The minimum RSS value is given to –50dBm to guarantee a reliable transmission. Our experiment shows that a receiver node with PRR less than 65% cannot receive two or more consecutive ACK packets. The another method to be taken in this paper to increase PRR depending on the type of crossing corridors is to deploy intermediate nodes with the shortest distance to its neighbors. This method conducts an efficient topology of multi-hop ad hoc wireless network.

Radar sensors offer enormous advantages as sensing devices for automated and autonomous driving. However, when multiple of such sensors are operated in a large number of cars, there is a high risk of the occurrence of mutual interference. In the currently widespread linearly frequency modulated sensors interference reduces the detection performance, especially for targets with a low radar cross section. In this paper the interference effects are suppressed with an adaptive beamforming scheme based on a mean square error minimization. The paper evaluates the algorithm with the help of a simulated and measured scenario, and discusses the occurring interference effects and the benefits of the beamforming approach.

This paper deals with a mini radar system aimed at detecting small targets at the low latitude. The radar operates at Ku-band in the frequency modulated continuous wave (FMCW) mode with two receiving channels. The radar system has the characteristics of compactness, mobility, and low power consumption. This paper focuses on the implementation of the radar system, and the Block least mean square (Block LMS) algorithm is applied to minimize the fortuitous distortion. It is validated from a series of experiments that the track of the unmanned aerial vehicle (UAV) can be easily distinguished with the radar system., {"references":["Sathyamoorthy, Dinesh. \"Statement on the Security Threat Posed by Unmanned Aerial Systems and Possible Countermeasures\", Oversight and Management Efficiency Subcommittee, Homeland Security Committee, Washington, DC, US House, (2015).","J. A. Bhatti, T. E. Humphreys, and B. M. Ledvina. \"Development and demonstration of a TDOA-based GNSS interference signal localization system\", in Proceedings of the IEEE/ION PLANS Meeting, pp. 1209–1220, (2012).","Ritchie M, Fioranelli F, Griffiths H, et al. \"Micro-drone RCS analysis\", Radar Conference, 2015 IEEE, pp. 452-456, (2015).","Olmos S, Sornmo L, Laguna P. \"Block adaptive filters with deterministic reference inputs for event-related signals: BLMS and BRLS\", IEEE Transactions on Signal Processing, vol. 50, pp. 1102-1112, (2002).","Manolakis D G, Ingle V K, Kogon S M. \"Statistical and adaptive signal processing: spectral estimation, signal modeling, adaptive filtering, and array processing.\" Artech House, (2005).","Im Y T, Ali M, Park S O. \"Slow modulation behavior of the FMCW radar for wireless channel sounding technology.\", IEEE Transactions on Electromagnetic Compatibility, vol. 56, pp. 1229-1237, (2014).","Soumya R G, Naveen N, Lal M J. \"Application of adaptive filter using adaptive line enhancer techniques\", International Conference on Advances in Computing and Communications, 2013 Third International Conference on. IEEE, pp. 165-168, (2013)."]}

This paper is focused to the most frequent shortcomings of WiFi technology operators seen by monitoring of broadband data transmission in frequency bands 2.4 GHz up to 66 GHz. The used process of measuring an evaluation of measured data summarized by the devices used by Czech Telecommunication Office for inspection and supervision is performed next. The paper is concluded by real examples of various shortcomings and mistakes. Tento článek je zaměřen na nejčastější nedostatky wi-fi operátorů zjištěné monitorováním širokopásmového datového přenosu v kmitočtových pásmech 2,4 GHz.

WMNs (Wireless Mesh Networks) represent a new trend in wireless communications, providing greater flexibility, reliability and better network performances than standard WLANs (Wireless Local Area Networks). Having in mind a need for more efficient and faster data transmission, one of the greatest challenges in designing WMNs is to provide greater throughput. This is done by introducing networks the nodes of which have multiple interfaces that can work on one of multiple channels (the channel is chosen by a predefined algorithm), so-called Multi-Channel Multi-Interface (MCMI) WMNs. In order to provide better network performances, it is necessary to define routing protocols and metrics used to find and select the optimal route from the source to the destination node. Since WMNs are characterised by a high dynamic range of the received signal level, especially when they are realized in complex environments such as indoors, it is necessary to define routing metrics that can follow these fast changes in propagation conditions that occur in each link in the network. This paper presents a critical review of the most well-known routing metrics for MCMI-WMNs. The paper is organised as follows: Introduction In this section, it is pointed that the need for wireless communications is growing in the modern society. Since wireless networks are widely used, the overall wireless communication is greatly increased. In order to provide greater throughput of user data, it is very important to select the optimal route between the source and the destination node. Therefore, a great attention is dedicated to creating an optimal routing protocol and routing metrics. Routing protocols have an important role in finding paths form the source to the destination nodes, and the routing metrics have the task to select the optimal route form multiple routes. Criteria for creating metrics In order to find the optimal metric, it is necessary to define criteria to be taken into account when the metric is formed. These criteria are: interference (intra-flow, inter-flow and external), the amount of information, link load, agility, stability and ability to track rapid changes at every link in the network. In this section, each of the criteria is defined and it is explained what a metric should have in order to satisfy the defined criteria. Overview of the metrics available in the literature In this section, the metrics available in the literature are described. Based on the criteria taken into account, metrics are divided into two categories: hop count metric and link-quality metrics. Link-quality metrics described in this paper are: ETX (Expected Transmission Count), LAETT (Load Aware Expected Transmission Time), EETT (Exclusive Expected Transmission Time), WCETT (Weighted Cumulative Expected Transmission Time), iAWARE (Interference Aware Routing), MIC (Metric of Interference and Channel-switching), powerETX, powerWCETT, and powerMIC. The rest of this section is organised into the following sub-sections: Hop count metric ETX (Expected Transmission Count) metric LAETT (Load Aware Expected Transmission Time) metric EETT (Exclusive Expected Transmission Time) metric WCETT (Weighted Cumulative Expected Transmission Time) metric iAWARE (Interference Aware Routing) metric MIC (Metric of Interference and Channel-switching) metric powerETX (power Expected Transmission Count) metric powerWCETT (power Weighted Cumulative Expected Transmission Time), and powerMIC (power Metric of Interference and Channel-switching) metrics In each of the sub-sections, a detailed description of a particular metric is given as well as its basic characteristics. The metric forming formulas are given as well. Comparative analysis of the described metrics In this section, the comparative analysis of the previously described metrics is given. Besides, the comparative analysis in the terms of throughput of user data and average end to end delay is provided, based on the results given in the literature. The analysis is performed on six metrics: ETX, WCETT, MIC, powerETX, powerWCETT and powerMIC. The first three metrics are chosen since they are most frequently used in the literature, and the other three metrics are formed based on the first three by introducing a parameter that follows fast changes in the state of each link independently. Conclusion In the final section, the concluding remarks are given. This section represents an overview of the entire paper, as well as the reasons why this subject was chosen as a topic of this paper.

The idea of adaptive usage of uplink frequency resources for other purposes, such as downlink data transmission, has attracted researchers for many years. As an extension of the conference paper on the same subject, this article discusses the concept of applying a multichannel simultaneous uplink and downlink transmission scheme for flexible duplexing, where the middle part of the so-called uplink component carrier is used for downlink data delivery. The realization of such an idea is based on the adaptive change of the transmit/reception mask at the base stations and/or mobile devices and the application of the non-contiguous transmission scheme. Beside a theoretical analysis, this paper provides the calculation results of the interference rise in the system.

The internet of Things (IoT) is used to interconnect a massive number of heterogeneous resource constrained smart devices. This makes such networks exposed to various types of malicious attacks. In particular, jamming attacks are among the most common harmful attacks to IoT networks. Therefore, an anti jamming power allocation strategy is first proposed in this paper for health monitoring IoT networks by exploiting game theory to minimize the worst case jamming effect under multi channel fading. This strategy uses an iterative algorithm based on gradient descent to identify the Nash Equilibrium (NE) of the game. An artificial neural network model is also proposed to accelerate the convergence of the algorithm making it more suitable for IoT networks. Furthermore, novel data population, extension and balancing techniques are proposed to enhance the efficiency of the proposed strategy in combating jamming attacks even for network configurations that were never used in the training phase. In addition, time and spatial diversity are exploited using a heterogeneous iterative algorithm to enhance the security of the network.

Crystal oscillators are widely used in electronic systems to provide reference timing signals. Even though they are designed to be highly stable, their performance can be deteriorated by several types of random noise sources and deterministic interferences. This paper investigates the phenomenon of timing jitter in crystal oscillators induced by the injection of deterministic interferences. It is shown that timing jitter is closely related to the phase and amplitude modulations of the oscillator response. A closed-form variational macromodel is proposed to quantify timing jitter as well as to qualitatively explain the interference mechanism. Analytical results and efficient numerical simulations are developed to explore how timing jitter depends on the frequency of the interfering signal. The methodology is tested by a crystal Pierce oscillator.

When a global navigation satellite system (GNSS) receiver suppresses interference in a dynamic scene, the direction of the interference signal arriving at the receiver may change rapidly. The null formed by the spatial filtering based on the array antenna will become wider and shallower, and the anti-jamming performance will deteriorate. A null-steering control technique based on a dual projection algorithm is proposed in this paper, which can effectively increase the depth of the null. In this paper, the dynamic model between the interference and the receiver is established first. Based on the model, the rate of change of the arrival direction of the interference is analyzed, and the phenomenon of the spatial filtering null becoming wider and shallower is simulated and verified. Then, the double projection algorithm is introduced to effectively deepen the null. The simulation results show that the proposed method can effectively increase the null depth by 30 to 50 dB, which significantly improves the anti-jamming performance of the spatial filtering in dynamic scenes.

The paper focuses on minimum mean square error (MMSE) Bayesian estimation for a Gaussian source impaired by additive Middleton's Class-A impulsive noise. In addition to the optimal Bayesian estimator, the paper considers also the soft-limiter and the blanker, which are two popular suboptimal estimators characterized by very low complexity. The MMSE-optimum thresholds for such suboptimal estimators are obtained by practical iterative algorithms with fast convergence. The paper derives also the optimal thresholds according to a maximum-SNR (MSNR) criterion, and establishes connections with the MMSE criterion. Furthermore, closed form analytic expressions are derived for the MSE and the SNR of all the suboptimal estimators, which perfectly match simulation results. Noteworthy, these results can be applied to characterize the receiving performance of any multicarrier system impaired by a Gaussian-mixture noise, such as asymmetric digital subscriber lines (ADSL) and power-line communications (PLC)., Comment: 30 pages, 13 figures, part of this work has been submitted to IEEE Signal Processing Letters

This paper analyses the use of femtocells connected into a single macro network infrastructure. Different problems and possible solutions were discussed. The paper is focused on two separate benefits, which HNB could bring an operator and user. Femtocells are especially appealing due to the freedom of installation, increased macro network capacity, femto zone rates and etc. They provide users with better service quality, including voice service and higher throughput; while operators can reduce their network deployment expenditures. On the other hand, unplanned deployment, mobility issues and different types of user groups can cause a headache both for operators and customers. The analysis demonstrated that the majority of features of femtocells from the operator’s point of view were positive. Looking from the user’s point of view, most of shortcomings are difficult to remove. Positive and negative features both for operators and clients are presented in the HNB model. Santrauka Darbe nagrinėjami femtocelių naudojimo, jungiant jas į bendrą makrotinklo infrastruktūrą, klausimai. Analizuojami kylantys sunkumai ir jų sprendimo variantai. Išskiriamos dvi: vartotojų bei operatorių – šakos, kuriose analizuojama femtocelių teikiama nauda. Lengvas diegimas, tinklo talpumo didinimas, naujų femtozonų atsiradimas. Visa tai femtoceles daro patrauklias šiandieniam naudojimui tinkluose. Vartotojo požiūriu užtikrinama balso skambučių kokybė, didelis duomenų pralaidumas. Be to, operatorius turi galimybę plėsti tinklą daug mažesnėmis sąnaudomis. Neplanuoto diegimo principai, mobilumas, skirtingo tipo vartotojų grupės gali sukelti didelių sunkumų vartotojui naudojantis femtocele, o operatoriui užtikrinti tinkamą jų funkcionavimą. Atlikta femtocelių savybių analizė rodo, kad operatoriaus požiūriu didžioji dalis HNB savybių yra teigiamos. Iš kliento pozicijos pasireiškiantys trūkumai šalinami sunkiai. Teigiamų ir neigiamų savybių pasiskirstymas operatoriaus ir kliento šakoms pateikiamas HNB modeliu. Reikšminiai žodžiai: femtocelė, HNB, UMTS, LTE, interferencija, CSG.

Radio Frequency (RF) signals transmitted by Global Navigation Satellite Systems (GNSS) are exploited as signals of opportunity in many scientific activities, ranging from sensing waterways and humidity of the terrain to the monitoring of the ionosphere. The latter can be pursued by processing the GNSS signals through dedicated ground-based monitoring equipment, such as the GNSS Ionospheric Scintillation and Total Electron Content Monitoring (GISTM) receivers. Nonetheless, GNSS signals are susceptible to intentional or unintentional RF interferences (RFIs), which may alter the calculation of the scintillation indices, thus compromising the quality of the scientific data and the reliability of the derived space weather monitoring products. Upon the observation of anomalous scintillation indices computed by a GISTM receiver in the Mediterranean area, the study presents the results of the analysis and characterization of a deliberate, unclassified interferer acting on the L1/E1 GNSS signal bands, observed and captured through an experimental, software defined radio setup. The paper also highlights the adverse impacts of the interferer on the amplitude scintillation indices employed in scientific investigations, and presents a methodology to discriminate among regular and corrupted scintillation data. To support further investigations, a dataset of baseband signals samples affected by the RFI is available at IEEE DataPort.

In cognitive research, speed and accuracy are two important aspects of performance. When analyzed separately, these performance variables sometimes lead to contradictory conclusions about the effect of a manipulation. To avoid such conflicts, several measures that integrate speed and accuracy have been proposed, but the added value of using such measures remains unclear. The present paper compares the relative utility of seven integrated performance measures, namely four variations on a binning procedure that weights response times of correct and incorrect trials differently, and three measures that combine averaged speed and accuracy scores. The properties of these integrated measures were explored in three simulation studies. The first study compared three binning measures and showed that one measure failed to grasp the performance difference between two conditions. The second study showed that the sampling distributions of the measures were symmetric, except for a strong skewness on the rate correct score. The third study varied the trade-off and the effect sizes of speed and accuracy in four different combinations of size and direction of speed and accuracy effects. These studies highlighted some further shortcomings of the binning measures. The combination measures performed well, but linear integration of speed and accuracy and rate correct score were most efficient in detecting effects and accounting for a larger proportion of the variance. The paper concludes that these combination measures are useful provided that also the speed and accuracy data are inspected.

The evolution of the railway sector depends, to a great extent, on the deployment of advanced railway signalling systems. These signalling systems are based on communication architectures that must cope with complex electromagnetical environments. This paper is outlined in the context of developing the necessary tools to allow the quick deployment of these signalling systems by contributing to an easier analysis of their behaviour under the effect of electromagnetical interferences. Specifically, this paper presents the modelling of the Eurobalise-train communication flow in a general purpose simulation tool. It is critical to guarantee this communication link since any lack of communication may lead to a stop of the train and availability problems. In order to model precisely this communication link we used real measurements done in a laboratory equipped with elements defined in the suitable subsets. Through the simulation study carried out, we obtained performance indicators of the physical layer such as the received power, SNR and BER. The modelling presented in this paper is a required step to be able to provide quality of service indicators related to perturbed scenarios. The work described in this paper is partially supported by the EU FP7-SEC-2011-1 Col-laborative Research Project entitled SECRET—SECurity of Railways against Electromagnetic aTtacks—and by the EU FP7 Research Project entitled EATS—ETCS Advanced Design Test- ing and Smart Train Positioning System. This work is also supported by the Spanish Min- istry of Economy and Competitiveness through the SAREMSIG TEC2013-47012-C2 project— Contribution to a Safe Railway Operation: Evaluating the effect of Electromagnetic Disturb- ances on Railway Control Signalling Systems. This work is partially produced within the Training and Research Unit UFI11/16 funded by the UPV/EHU.

In den letzten Jahren war ein Stillstand in den Bemühungen zur Rüstungskontrolle und Abrüstung zu beobachten, während zugleich der Fortbestand von früheren Errungenschaften auf dem Gebiet nicht gewährleistet scheint. Dies resultiert nicht allein aus dem Umstand, dass sich die Beziehungen zwischen den USA/NATO und Russland deutlich verschlechtert haben, ist sondern auch auf Probleme und Komplexitäten zurückzuführen, die dem Bereich der Rüstungskontrolle und Abrüstung eigen sind und sich aus den Interferenzen und Wechselwirkungen zwischen unterschiedlichen Waffentypen - bereits vorhanden oder noch in Entwicklung - und verschiedenen Regionen ergeben. Dieses Papier beleuchtet und diskutiert diese Wechselwirkungen entlang unterschiedlicher Achsen (Materie, Region und Zeit) und veranschaulicht auf diesem Wege die Herausforderungen, mit denen die Rüstungskontrolle und Abrüstung in Europa in diesem Zusammenhang konfrontiert sind., Efforts to bring forward disarmament and arms control have not only experienced a standstill in recent years, there is even a reverse trend jeopardizing the conservation of agreements and comprises struck before. This is not solely due to the deteriorating relationship between the US/NATO and Russia, but also a consequence of complexities and problems specific to the realm of arms control and disarmament given in the face of interferences and interdependencies between various weapons types - both deployed and still in development - and different regions. This paper shows and discusses such interdependencies along various axes (materiel, region and time) and highlights related challenges confronting arms control and disarmament in Europe.