MIMO Channel Correlation in General Scattering Environments

This paper presents an analytical model for the fading channel correlation in general scattering environments. In contrast to the existing correlation models, our new approach treats the scattering environment as non-separable and it is modeled using a bi-angular power distribution. The bi-angular power distribution is parameterized by the mean departure and arrival angles, angular spreads of the univariate angular power distributions at the transmitter and receiver apertures, and a third parameter, the covariance between transmit and receive angles which captures the statistical interdependency between angular power distributions at the transmitter and receiver apertures. When this third parameter is zero, this new model reduces to the well known "Kronecker" model. Using the proposed model, we show that Kronecker model is a good approximation to the actual channel when the scattering channel consists of a single scattering cluster. In the presence of multiple remote scattering clusters we show that Kronecker model over estimates the performance by artificially increasing the number of multipaths in the channel.Comment: Australian Communication Theory Workshop Proceedings 2006, Perth Western Australia. (accepted

Comparison of sound reproduction using higher order loudspeakers and equivalent line arrays in free-field conditions

Higher order sound sources of Nth order can radiate sound with 2N + 1 orthogonal radiation patterns, which can be represented as phase modes or, equivalently, amplitude modes. This paper shows that each phase mode response produces a spiral wave front with a different spiral rate, and therefore a different direction of arrival of sound. Hence, for a given receiver position a higher order source is equivalent to a linear array of 2N + 1 monopole sources. This interpretation suggests performance similar to a circular array of higher order sources can be produced by an array of sources, each of which consists of a line array having monopoles at the apparent source locations of the corresponding phase modes. Simulations of higher order arrays and arrays of equivalent line sources are presented. It is shown that the interior fields produced by the two arrays are essentially the same, but that the exterior fields differ because the higher order sources produces different equivalent source locations for field positions outside the array. This work provides an explanation of the fact that an array of L Nth order sources can reproduce sound fields whose accuracy approaches the performance of (2N + 1)L monopoles

Dependence of MIMO System Performance on the Joint Properties of Angular Power

In this paper, we use a novel MIMO channel model to characterize the dependence of ergodic capacity and diversity order on the joint statistics of the angular power density. The scattering environment of a MIMO channel is characterized by a double directional angular power distribution, describing the power transferred in each direction from transmitter aperture to receiver aperture. Angular power, which is typically separable Kronecker-modelled, is here generalized to include joint distribution properties using well-known bivariate probability density functions. We show that the joint properties of the power density, namely the shape and the orientation of power distribution contours, have significant impact on capacity and diversity of non-line-of-sight (NLOS) channels

Differences in executive functions between athletes and non-athletes

Cilj ovog istraživanja bio je ispitati razlike u izvršnim funkcijama između sportaša i nesportaša, a zatim ispitati razlikuju li se izvršne funkcije kod sportaša s obzirom na vrstu sporta kojim se bave („izvana upravljani“ ili „samoupravljani“ sportovi). Istraživanje je provedeno online, na uzorku od 65 aktivnih sportaša (od čega se 35 bavilo „izvana upravljanim“, a 30 „samoupravljanim“ sportovima) te 60 nesportaša u dobi od 18 do 30 godina. Osim sociodemografskog i PANAS upitnika, sudionici su rješavali i zadatke pomoću kojih se određivala razvijenost tri izvršne funkcije: inhibicije, ažuriranja i premještanja. Rezultati su pokazali kako ne postoji statistički značajna razlika između sportaša i nesportaša na navedenim zadacima izvršnih funkcija. Statistički značajne razlike nisu pronađene ni s obzirom na vrstu sporta. Drugim riječima, sportaši, bez obzira na vrstu sporta kojom se bave, nisu bili uspješniji na zadacima izvršnih funkcija inhibicije, ažuriranja i premještanja od nesportaša. Ipak, treba uzeti u obzir i nedostatke ovog istraživanja te provesti dodatne studije kako bi se odnos sporta i izvršnog funkcioniranja bolje razjasnio.The aim of this study was to investigate differences in executive functions between athletes and non-athletes and also investigate whether differences in executive functions exist considering the type of sports (externally paced and self - paced sports). A total of 65 athletes (35 externally paced and 30 self-paced athletes) and 60 non-athletes participated in this online study, with ages ranging from 18 to 30. Apart from sociodemographic and PANAS questionnaire, computer-based tasks were also used for measuring three main executive functions among participants: inhibition, updating and switching. Results did not show any differences between athletes and non-athletes, neither between externally paced and self-paced athletes. In other words, results of this study showed that athletes did not have higher scores on executive function measures compared to non-athletes. Limitations of this study should be kept in mind, and also, further research is necessary to reveal more information about relationship between sport and executive functioning

„Ahol a szarvas inni jár..."

The art education on the one hand is shaping personality, on the other hand is shaping the aesthetic skills. The great advantage of the creative process is that it gives the same opportunity to children of small abilities and spell bakers. The co-operative forms of work based on cooperative learning methods, which provide opportunities for more sim-ultaneous interactions. In these the most important is to developing key competencies and implementing differentiated education. The benefits of pair work and teamwork is, for example, they can interpret their experiences several ways, they are forced to reflect on their own solutions, and are forced to think them further. I'd like to focus on these as-pects in Bartók's Cantana Profana, because this composition is very suitable for the co-operativ processing techniques.The art education on the one hand is shaping personality, on the other hand is shaping the aesthetic skills. The great advantage of the creative process is that it gives the same opportunity to children of small abilities and spell bakers. The co-operative forms of work based on cooperative learning methods, which provide opportunities for more sim-ultaneous interactions. In these the most important is to developing key competencies and implementing differentiated education. The benefits of pair work and teamwork is, for example, they can interpret their experiences several ways, they are forced to reflect on their own solutions, and are forced to think them further. I'd like to focus on these as-pects in Bartók's Cantana Profana, because this composition is very suitable for the co-operativ processing techniques

Acoustic Signal Processing Algorithms for Reverberant Environments

This thesis investigates the design and the analysis of acoustic signal processing algorithms in reverberant rooms. Reverberation poses a major challenge to acoustic signal processing problems. It degrades speech intelligibility and causes many acoustic algorithms that process sound to perform poorly. Current solutions to the reverberation problem frequently only work in lightly reverberant environments. There is need to improve the reverberant performance of acoustic algorithms.¶ The approach of this thesis is to explore how the intrinsic properties of reverberation can be exploited to improve acoustic signal processing algorithms. A general approach to soundfield modelling using statistical room acoustics is applied to analyze the reverberant performance of several acoustic algorithms. A model of the underlying structure of reverberation is incorporated to create a new method of soundfield reproduction.¶ Several outcomes resulting from this approach are: (i) a study of how more sound capture with directional microphones and beamformers can improve the robustness of acoustic equalization, (ii) an assessment of the extent to which source tracking can improve accuracy of source localization, (iii) a new method of soundfield reproduction for reverberant rooms, based upon a parametrization of the acoustic transfer function and (iv) a study of beamforming to directional sources, specifically exploiting the directionality of human speech.¶ The approach to soundfield modelling has permitted a study of algorithm performance on important parameters of the room acoustics and the algorithm design. The performance of acoustic equalization and source tracking have been found to depend not only on the levels of reverberation but also on the correlation of pressure between points in reverberant soundfields. This correlation can be increased by sound capture with directional capture devices. Work on soundfield reproduction has shown that, though reverberation significantly degrades the performance of conventional techniques, by accounting for the reverberation it is possible to design reproduction methods that function well in reverberant environments

The evolutionary basis of aggressive behavior

Prvi oblici agresije kod ljudi datiraju još daleko u prapovijest, a agresivno ponašanje nije strano ni životinjama. Pretpostavlja se kako agresivno ponašanje, stoga, može imati evolucijsku osnovu. Evolucijska psihologija naglašava interakcionistički pristup pri objašnjavanju agresije, zbog čega neće biti predstavljena jedna opća, već više kontekstualno-specifičnih teorija. Cilj ovog rada je proučavanje različitih oblika agresivnog ponašanja iz evolucijske perspektive. U radu će se predstaviti generalne teorije agresije kao rješenja za adaptivne probleme, a to su: prisvajanje tuđih resursa, obrana od napada, nametanje troškova istospolnim suparnicima, uspostavljanje statusa i hijerarhija moći, odvraćanje suparnika od buduće agresije, odvraćanje dugoročnih partnerica od seksualne nevjere te eliminranje genetski nesrodnih potomaka. Uz to će se opisati i nešto specifičnije teme koje se tiču agresivnog ponašanja, poput silovanja, agresivnog ponašanja kod tinejdžerki te koalicijskog ratovanja. Objasnit će se i spolne razlike kod agresivnog ponašanja, kao i razlozi agresije koja je usmjerena prema djeci. Spomenut će se i spolne i kontekstualne razlike kod preferencije direktnih i indirektnih oblika agresivnog ponašanja. Nadalje, predstavit će se teorije koje tumače posebno izraženo agresivno ponašanje kod muškaraca. Iako evolucijska psihologija ne pruža nijednu hipotezu o porijeklu agresije, velik broj istraživanja i nalaza omogućuju bolje razumijevanje agresivnog ponašanja kao evoluiranog mehanizma za rješavanje adaptivnih problema

The evolutionary basis of aggressive behavior

Prvi oblici agresije kod ljudi datiraju još daleko u prapovijest, a agresivno ponašanje nije strano ni životinjama. Pretpostavlja se kako agresivno ponašanje, stoga, može imati evolucijsku osnovu. Evolucijska psihologija naglašava interakcionistički pristup pri objašnjavanju agresije, zbog čega neće biti predstavljena jedna opća, već više kontekstualno-specifičnih teorija. Cilj ovog rada je proučavanje različitih oblika agresivnog ponašanja iz evolucijske perspektive. U radu će se predstaviti generalne teorije agresije kao rješenja za adaptivne probleme, a to su: prisvajanje tuđih resursa, obrana od napada, nametanje troškova istospolnim suparnicima, uspostavljanje statusa i hijerarhija moći, odvraćanje suparnika od buduće agresije, odvraćanje dugoročnih partnerica od seksualne nevjere te eliminranje genetski nesrodnih potomaka. Uz to će se opisati i nešto specifičnije teme koje se tiču agresivnog ponašanja, poput silovanja, agresivnog ponašanja kod tinejdžerki te koalicijskog ratovanja. Objasnit će se i spolne razlike kod agresivnog ponašanja, kao i razlozi agresije koja je usmjerena prema djeci. Spomenut će se i spolne i kontekstualne razlike kod preferencije direktnih i indirektnih oblika agresivnog ponašanja. Nadalje, predstavit će se teorije koje tumače posebno izraženo agresivno ponašanje kod muškaraca. Iako evolucijska psihologija ne pruža nijednu hipotezu o porijeklu agresije, velik broj istraživanja i nalaza omogućuju bolje razumijevanje agresivnog ponašanja kao evoluiranog mehanizma za rješavanje adaptivnih problema