Performance evaluation of decode and forward cooperative diversity systems over nakagami-m fading channels with non-identical interferers

The deficiencies of regular cooperative relaying schemes were the main reason behind the development of Incremental Relaying (IR). Fixed relaying is one of the regular cooperative relaying schemes and it relies on using the relay node to help in transmitting the signal of the source towards the destination despite the channel’s condition. However, adaptive relaying methods allocate the channel resources efficiently; thus, such methods have drawn the attention of researchers in recent years. In this study, we analyze a two-hop Decode-and-Forward (DF) IR system’s performance via Nakagami-m fading channels with the existence of the several L distinguishable interferers placed close to the destination which diminishes the overall performance of the system due to the co-channel interference. Tight formulas for the Bit Error Rate (BER) and the Outage Probability (OP) are drawn. The assumptions are consolidated by numerical calculations

Detection and decoding algorithms of multi-antenna diversity techniques for terrestrial DVB systems

This PhD dissertation analyzes the behavior of multi-antenna diversity techniques in broadcasting scenarios of TDT (terrestrial digital television) systems and proposes a low-complexity detection and decoding design for their practical implementation. For that purpose, the transmission-reception chains of the European DVB-T (Digital Video Broadcasting - Terrestrial) and DVB-T2 standards have been implemented over which diversity and MIMO (multiple-input multiple-output) techniques have been assessed through Monte Carlo simulations. On one hand, the most important multi-antenna diversity techniques such as CDD (cyclic delay diversity), Alamouti code-based SFBC (space-frequency block coding) and MRC (maximum ratio combining), have been evaluated in a DVB-T system over both fixed and mobile Rayleigh and Ricean channels. With the DVB-T2 standard release, multi-antenna processing has actually been introduced in digital television systems. The distributed SFBC configuration proposed in DVB-T2 is analyzed from a performance point of view considering different propagation conditions in an SFN (single frequency network). On the other hand, error-performance and detection complexity analyses of 2x2 FRFD (full-rate full-diversity) SFBCs are carried out for last-generation DTV (digital television) systems. The use of channel coding based on LDPC (low-density parity check) codes in new standards such as DVB-T2, involves a soft-output MAP (maximum a posteriori ) detection which results in an increase of the detection complexity. In order to study the FRFD codes behavior in such a BICM (bit-interleaved coded modulation) scheme, the Golden code, which achieves the maximum coding gain, and the Sezginer-Sari code, which has a lower inherent detection complexity as an expense of sacrificing performance gain, have been chosen. Using LSD (list sphere decoder) detection, BER (bit error rate) performance and computational cost results are provided for TDT scenarios. In order to overcome the variable complexity of the LSD, LFSD (list fixed-complexity sphere decoder) detection is proposed for practical implementations. A redesign of the previously proposed LFSD algorithm for spatial multiplexing MIMO systems has been performed for FRFD SFBCs with close-to-LSD performance. Furthermore, an analysis of the number of candidates is carried out in order to maximize the eficiency of the algorithm. Due to its fixed complexity, the novel algorithm can be fully pipelined making feasible a realistic implementation in chip.Esta tesis analiza el comportamiento de las técnicas de diversidad multiantena en escenarios de radiodifusión TDT (televisión digital terrestre) y propone un diseño de baja complejidad para la detección de códigos SFBC (space-frequency block coding ) que facilita una posible implementación práctica. Para ello, se ha implementado la cadena de transmisión-recepción de los estándares europeos DVB-T (Digital Video Broadcasting - Terrestrial ) y DVB-T2 como entorno de trabajo donde se han incluido y simulado diferentes técnicas de diversidad MIMO (multiple-input multiple-output ). Por un lado, se evalúan las técnicas de diversidad multiantena CDD ( cyclic delay diversity), SFBC con codi cación Alamouti y MRC (maximum ratio combining ) en escenarios fijos y móviles de canales tanto Rayleigh como Ricean para el sistema DVB-T. En DVB-T2, se analiza la tecnología multiantena propuesta por el estándar para diferentes escenarios de propagación dentro de redes SFN (single frequency network ). Por otro lado, se realiza un estudio sobre códigos FRFD (full-rate full-diversity ) SFBC para su posible inclusión en futuros estándares de televisión digital. El uso de codificaciones de canal más potentes, como los códigos LDPC (low-density parity check ), implica la utilización de una detección MAP (maximum a posteriori ) con salida soft, incrementando considerablemente la complejidad de la detección. Para realizar el correspondiente análisis de complejidad y rendimiento, se han escogidos dos códigos FRFD. Por un lado, el código Golden, que ofrece la máxima ganancia de código y, por otro, el código propuesto por Sezginer y Sari, que consigue reducir la complejidad de detección a costa de perder cierta ganancia de código. Se presentan resultados basados en curvas de BER (bit error rate) y número de operaciones sobre un sistema BICM (bit-interleaved coded modulation ) equivalente a DVB-T2 en escenarios TDT utilizando una detección LSD (list sphere decoder ). Para resolver el problema de la complejidad variable del algoritmo LSD, se realiza un rediseño del ya propuesto LFSD (list fixed-complexity sphere decoder ) para técnicas de multiplexación espacial considerando la estructura de los códigos FRFD SFBC. Asimismo, se evalúa el número de candidatos que ofrece un funcionamiento más eficiente con menor coste computacional. Los resultados de simulación basados en curvas de BER muestran rendimientos cercanos al detector LSD manteniendo el número de operaciones constante. Por lo tanto, este nuevo diseño permite su eficiente y práctica implementación en dispositivos reales.Doktoretza-tesi honen gai nagusia Lurreko Telebista Digitalerako antena anitzeko dibertsitate tekniken portaera ikertzea da, hartzailerako konplexutasun baxuko algoritmoen diseinua oinarri hartuta. Horretarako, Europako DVB-T eta DVB-T2 telebista digitaleko estandarren igorle-hartzaile kateen simulagailua inplementatzeaz gain, dibertsitate eta MIMO ( multipleinput multiple-output ) algoritmoak garatu eta aztertu dira. Lehenengo helburu gisa, CDD (cyclic delay diversity ), Alamouti kodean oinarritutako SFBC (space-frequency block coding ) eta MRC (maximum ratio combining ) teknikak ebaluatu dira Rayleigh eta Ricean ingurunetan, bai komunikazio nko zein mugikorretarako. Argitaratu berri den DVB-T2 estandarrak antena anitzeko prozesaketa telebista sistema digitalean sartu duenez, teknologia honen analisia egin da maiztasun bakarreko telebista sareetarako SFN (single frequency network ). Tesiaren helburu nagusia FRFD (full-rate full-diversity ) SFBC kodigoen ikerketa eta hauek telebista digitalaren estandar berrietan sartzea ahalbidetuko dituzten detekzio sistemen diseinua izan da. Kanalen kodi kazio indartsuagoak erabiltzeak, LDPC ( low-density parity check ) kodeak esaterako, MAP (maximum a posteriori ) algoritmoan oinarritutako soft irteeradun detektoreen erabilera dakar berekin, detekzioaren konplexutasuna areagotuz. Bi FRFD kode aukeratu dira errendimendu eta konplexutasun analisiak DVB-T2 bezalako BICM (bit-interleaved coded modulation ) sistemetan egiteko. Alde batetik, irabazi maximoa lortzen duen Golden kodea eta, bestetik, konplexutasun txikiagoa duen Sezginer eta Sarik proposatutako kodea erabili dira. Bit errore edo BER (bit error rate) tasan eta konputazio kostuan oinarrituta, emaitzak aurkeztu dira zerrenda dekodeatzaile esferikoa ( list sphere decoder, LSD) erabiliz. LSD-aren konplexutasun aldakorraren arazoa konpontzeko, ezpazio-multiplexazioko teknikarako LFSD (list xed-complexity sphere decoder ) algoritmoaren berdiseinua garatu da, FRFD SFBC kodeen egitura berezia kontuan hartuta. Algoritmoaren eraginkortasuna maximizatzeko kandidatuen zenbakia ebaluatzen da baita ere. LSD-en antzeko errendimendua duten BER gra ketan oinarritutako simulazio emaitzak aurkezten dira, eragiketa kopurua konstante eta LSD-arenaren baino murritzagoa mantenduz. Beraz, proposatutako diseinu eraginkorrak, FRFD SFBC antena anitzeko dibertsitatean oinarritutako eskemen inplementazioa ahalbidetu dezakete telebista digitalaren estandar berrietarako

EEG Source Imaging Indices of Cognitive Control Show Associations with Dopamine System Genes.

Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness

Mobile and Wireless Communications

Mobile and Wireless Communications have been one of the major revolutions of the late twentieth century. We are witnessing a very fast growth in these technologies where mobile and wireless communications have become so ubiquitous in our society and indispensable for our daily lives. The relentless demand for higher data rates with better quality of services to comply with state-of-the art applications has revolutionized the wireless communication field and led to the emergence of new technologies such as Bluetooth, WiFi, Wimax, Ultra wideband, OFDMA. Moreover, the market tendency confirms that this revolution is not ready to stop in the foreseen future. Mobile and wireless communications applications cover diverse areas including entertainment, industrialist, biomedical, medicine, safety and security, and others, which definitely are improving our daily life. Wireless communication network is a multidisciplinary field addressing different aspects raging from theoretical analysis, system architecture design, and hardware and software implementations. While different new applications are requiring higher data rates and better quality of service and prolonging the mobile battery life, new development and advanced research studies and systems and circuits designs are necessary to keep pace with the market requirements. This book covers the most advanced research and development topics in mobile and wireless communication networks. It is divided into two parts with a total of thirty-four stand-alone chapters covering various areas of wireless communications of special topics including: physical layer and network layer, access methods and scheduling, techniques and technologies, antenna and amplifier design, integrated circuit design, applications and systems. These chapters present advanced novel and cutting-edge results and development related to wireless communication offering the readers the opportunity to enrich their knowledge in specific topics as well as to explore the whole field of rapidly emerging mobile and wireless networks. We hope that this book will be useful for students, researchers and practitioners in their research studies

Statističke karakteristike prvog i drugog reda signala u bežičnom telekomunikacionom sistemu sa selekcionim kombinovanjem

In doctoral dissertation, first and second order system performances of wireless communication system in the presence of fading and interference are considered. Theoretically, four cases are taken into consideration, and obtained numerical results are graphically presented and analyzed. Firstly, wireless mobile communication system with the receiver that contains automatic frequency control (AFC) loop operating over fading channel in the presence of single interference is considered. Performance measures, such as average switching rate (ASR) and mean time lose of lock (MTTL), are defined. In this doctoral dissertation, ASR and MTTL, for three different fading channels: Kg, α-μ and k-μ are obtained. In the next chapter, wireless relay communication system with two sections in the presence of multipath fading is considered. Signal envelope at the input of the receiver can be expressed as product of the first section signal envelope and the second section signal envelope. For such system model, average level crossing rate (LCR) for the case when radio relay system of the first section operates over Nakagami-m fading environment and second section operates over k-μ fading environment is obtained. Wireless relay system with two sections in the presence of non-linear α-μ fading channel is than taken into consideration. Moreover, radio relay system with two sections in the presence of multipath fading and interference is also considered. LCR of the ratio of the product of two k-μ random processes and k-μ random process is calculated. Finally, LCR of the ratio of Rician random process and product of two Rician random processes is obtained. Wireless communication system with two inputs SSC diversity receiver operating over correlated multipath η-μ fading in the presence of interference is than considered. Joint probability density function and joint distribution cumulative function of the ratios of signal to interference at inputs of SSC receivers are calculated. By using obtained expressions for probability density function (PDF), average bit error probability (ABER) for different coherent and non-coherent modulation schemes is obtained while by using derived cumulative distribution function (CDF), outage probability (OP) is obtained. At the end of doctoral dissertation, macrodiversity system with macrodiversity SSC receiver and two microdiversity SC receivers operating over Gamma shadowed multipath fading channel is proposed. In one case Nakagami-m multipath fading channel is considered while in the second case k-μ multipath fading is considered. System performances of the proposed system are derived and numerical results are graphically presented and discusse

Uncovering the Hidden Cognitive Processes and Underlying Dynamics of Deception

This dissertation examines the processing demands associated with motor responding and verbal statements during deceptive (or deceptive-like) behavior. In the first set of studies presented in Chapter 2, participants motor movements in a false response paradigm revealed signatures of competition with the truth. In a second set of studies presented in Chapter 3, deceptive participants used language that reflected cognitive and social demands inherent to various types of deception. In evaluating both motor and verbal cues, this dissertation provides a comprehensive, multi-modal approach to better understanding the cognitive processes underlying deception. in conducting the motor responding studies, participants\u27 arm movements were analyzed as they navigated a motor tracking device (computer-mouse, Nintendo Wiimote). To visually co-present response options, where the true option acts as a competitor to a false target. In an initial study, competition during deceptive responding was shown to be much greater than during truthful responding. In two follow-up studies, the introduction of various task-based cognitive demands was shown to systematically modulate response performance. Specifically, these studies suggest that an intention to false respond early in question presentation will amplify competition effects, and that false responding to information in autobiographical memory is much more difficult than responding to information in general semantic memory. In the studies analyzing verbal statements, the focus is turned to large-scale linguistic analyses using automated natural language processing tools. In the first study, changes in language use were identifed between deceptive and truthful narratives using six psychologically relevant categories. A major finding was that the language of deception is adapted to faciliate ease of cognitive processing. In a second study, the indicative phrasing and semantic content of deceptive texts was extracted using a contrastive corpus analysis, whereby indicative features are defined by frequent use in one corpus while being infrequent in a comparative corpus. Two contexts of deception were evaluated. In the first context of computer-mediated conversations, decievers used a range of unique thematic elements, as in avoiding personal involvement in their narrative accounts. In the second context of attitudes towards abortion, unique thematic elements once again emerged; for example, participants tended to position their arguments in terms of formal law

Myomegalin is a novel A-kinase anchoring protein involved in the phosphorylation of cardiac myosin binding protein C

<p>Abstract</p> <p>Background</p> <p>Cardiac contractility is regulated by dynamic phosphorylation of sarcomeric proteins by kinases such as cAMP-activated protein kinase A (PKA). Efficient phosphorylation requires that PKA be anchored close to its targets by A-kinase anchoring proteins (AKAPs). Cardiac Myosin Binding Protein-C (cMyBPC) and cardiac troponin I (cTNI) are hypertrophic cardiomyopathy (HCM)-causing sarcomeric proteins which regulate contractility in response to PKA phosphorylation.</p> <p>Results</p> <p>During a yeast 2-hybrid (Y2H) library screen using a trisphosphorylation mimic of the C1-C2 region of cMyBPC, we identified isoform 4 of myomegalin (MMGL) as an interactor of this N-terminal cMyBPC region. As MMGL has previously been shown to interact with phosphodiesterase 4D, we speculated that it may be a PKA-anchoring protein (AKAP).</p> <p>To investigate this possibility, we assessed the ability of MMGL isoform 4 to interact with PKA regulatory subunits R1A and R2A using Y2H-based direct protein-protein interaction assays. Additionally, to further elucidate the function of MMGL, we used it as bait to screen a cardiac cDNA library. Other PKA targets, viz. CARP, COMMD4, ENO1, ENO3 and cTNI were identified as putative interactors, with cTNI being the most frequent interactor.</p> <p>We further assessed and confirmed these interactions by fluorescent 3D-co-localization in differentiated H9C2 cells as well as by <it>in vivo </it>co-immunoprecipitation. We also showed that quantitatively more interaction occurs between MMGL and cTNI under β-adrenergic stress. Moreover, siRNA-mediated knockdown of MMGL leads to reduction of cMyBPC levels under conditions of adrenergic stress, indicating that MMGL-assisted phosphorylation is requisite for protection of cMyBPC against proteolytic cleavage.</p> <p>Conclusions</p> <p>This study ascribes a novel function to MMGL isoform 4: it meets all criteria for classification as an AKAP, and we show that is involved in the phosphorylation of cMyBPC as well as cTNI, hence MMGL is an important regulator of cardiac contractility. This has further implications for understanding the patho-aetiology of HCM-causing mutations in the genes encoding cMyBPC and cTNI, and raises the question of whether MMGL might itself be considered a candidate HCM-causing or modifying factor.</p