T-dualization of type II superstring theory in double space

In this article we offer the new interpretation of T-dualization procedure of type II superstring theory in double space framework. We use the ghost free action of type II superstring in pure spinor formulation in approximation of constant background fields up to the quadratic terms. T-dualization along any subset of the initial coordinates, $x^a$, is equivalent to the permutation of this subset with subset of the corresponding T-dual coordinates, $y_a$, in double space coordinate $Z^M=(x^\mu,y_\mu)$. Demanding that the T-dual transformation law after exchange $x^a\leftrightarrow y_a$ has the same form as initial one, we obtain the T-dual NS-NS and NS-R background fields. The T-dual R-R field strength is determined up to one arbitrary constant under some assumptions. The compatibility between supersymmetry and T-duality produces change of bar spinors and R-R field strength. If we dualize odd number of dimensions $x^a$, such change flips type IIA/B to type II B/A. If we T-dualize time-like direction, one imaginary unit $i$ maps type II superstring theories to type $II^\star$ ones.Comment: Fermionic correction for bar variables and fields is clarified. Section 2 is substantially improved; Additional explanations added in the Introductio

T-duality diagram for a weakly curved background

In one of our previous papers we generalized the Buscher T-dualization procedure. Here we will investigate the application of this procedure to the theory of a bosonic string moving in the weakly curved background. We obtain the complete T-dualization diagram, connecting the theories which are the result of the T-dualizations over all possible choices of the coordinates. We distinguish three forms of the T-dual theories: the initial theory, the theory obtained T-dualizing some of the coordinates of the initial theory and the theory obtained T-dualizing all of the initial coordinates. While the initial theory is geometric, all the other theories are non geometric and additionally nonlocal. We find the T-dual coordinate transformation laws connecting these theories and show that the set of all T-dualizations forms an Abelian group

Modelling and optimisation of design of non-conventional instrument transformers

In this paper, we have proposed, modelled and optimised several designs of non-conventional instrument transformer (NCIT) for high voltage overhead transmission lines (400kV). We have discussed several parameters and investigated how they influence the sensitivity of our NCIT, consisting of magnetic shape memory (MSM) element, magnetic circuit and an LVDT (linear variable differential transformer). One of the most used conductors in these lines, 528-Al1/69-ST1A ACSR conductor (old code MOOSE), was modelled together with the MSM element and the magnetic circuit in ANSYS APDL. Based on the obtained results we have given suggestions on how NCIT could be designed taking into account a choice of the most appropriate material for this application. The way how the model was developed was presented as well as calculations of errors in the model in ANSYS APDL for electromagnetic problems

Noncommutativity and nonassociativity of closed bosonic string on T-dual toroidal backgrounds

In this article we consider closed bosonic string in the presence of constant metric and Kalb-Ramond field with one non-zero component, $B_{xy}=Hz$, where field strength $H$ is infinitesimal. Using Buscher T-duality procedure we dualize along $x$ and $y$ directions and using generalized T-duality procedure along $z$ direction imposing trivial winding conditions. After first two T-dualizations we obtain $Q$ flux theory which is just locally well defined, while after all three T-dualizations we obtain nonlocal $R$ flux theory. Origin of non-locality is variable $\Delta V$ defined as line integral, which appears as an argument of the background fields. Rewriting T-dual transformation laws in the canonical form and using standard Poisson algebra, we obtained that $Q$ flux theory is commutative one and the $R$ flux theory is noncommutative and nonassociative one. Consequently, there is a correlation between non-locality and closed string noncommutativity and nonassociativity

FIFTY YEARS OF MICROPROCESSOR EVOLUTION: FROM SINGLE CPU TO MULTICORE AND MANYCORE SYSTEMS

Nowadays microprocessors are among the most complex electronic systems that man has ever designed. One small silicon chip can contain the complete processor, large memory and logic needed to connect it to the input-output devices. The performance of today's processors implemented on a single chip surpasses the performance of a room-sized supercomputer from just 50 years ago, which cost over $ 10 million [1]. Even the embedded processors found in everyday devices such as mobile phones are far more powerful than computer developers once imagined. The main components of a modern microprocessor are a number of general-purpose cores, a graphics processing unit, a shared cache, memory and input-output interface and a network on a chip to interconnect all these components [2]. The speed of the microprocessor is determined by its clock frequency and cannot exceed a certain limit. Namely, as the frequency increases, the power dissipation increases too, and consequently the amount of heating becomes critical. So, silicon manufacturers decided to design new processor architecture, called multicore processors [3]. With aim to increase performance and efficiency these multiple cores execute multiple instructions simultaneously. In this way, the amount of parallel computing or parallelism is increased [4]. In spite of mentioned advantages, numerous challenges must be addressed carefully when more cores and parallelism are used.This paper presents a review of microprocessor microarchitectures, discussing their generations over the past 50 years. Then, it describes the currently used implementations of the microarchitecture of modern microprocessors, pointing out the specifics of parallel computing in heterogeneous microprocessor systems. To use efficiently the possibility of multi-core technology, software applications must be multithreaded. The program execution must be distributed among the multi-core processors so they can operate simultaneously. To use multi-threading, it is imperative for programmer to understand the basic principles of parallel computing and parallel hardware. Finally, the paper provides details how to implement hardware parallelism in multicore systems

MORFOLOŠKA VARIJABILNOST LISTOVA CRNE TOPOLE (Populus nigra L.) NA PODRUČJU VOJVODINE, SRBIJA

Morphological study of intra and interpopulation variability of black poplar leaves was carried on four natural populations located in the basin of the major rivers at the area of Vojvodina, Serbia. Research was conducted on the basis of nine leaf morphometric parameters, with descriptive and multivariate statistical analysis. Results show that within and between studied populations exists considerable variability, with the variability much more pronounced within than between populations. Given that the environmental conditions of investigated locations are uniform, it is assumed that the variability is consequences of the specific gene pool of these populations.Crna topola (Populus nigra L.) predstavlja jednu od bitnih pionirskih drvenastih vrsta (Pospiškova et al. 2004) koja je prilagođena specifičnim uvijetima poplavnog područja. Budući da unatrag nekoliko desetljeća čovek intenzivno kontroliše plavna područja, utvrđeno je da prirodna staništa autohtonih ritskih vrsta polako nestaju. Uzevši u obzir nestanak ovih ekosustava, prekomjernu eksploataciju autohtonih topola, introdukciju superiornih hibrida topola i mogućnost introgresija gena kultiviranih topola, crna topola se smatra ugroženom vrstom. Kako bi se mogle primijeniti odgovarajuće metode konzervacije, potrebno je utvrditi postojanje varijabilnosti unutar preostalih prirodnih populacija (Flush et al. 2002). Varijabilnost postojećih prirodnih populacija crne topole na području Vojvodine je u ovom istraživanju ispitana pomoću niza morfoloških svojstava lista.Istraživanja unutarpopulacijske i međupopulacijske morfološke varijabilnosti listova crne topole (Populus nigra L.) rađeno je na razini četiri prirodne populacije koje se nalaze u dolinama najvećih rijeka Vojvodine (Dunav, Tisa, Sava – Slika 1). Skupljanje uzoraka obavljeno je metodom slučajnog odabira u tijeku vegetacijskog perioda kada su listovi potpuno razvijeni. Prikupljeni su listovi srednjeg djela grančice dugorasta koje Tucović (1965) ističe kao najvažnije za karakteriziranje pojedinih sistematskih kategorija. Na herbariziranom materijalu analizirano je devet morfometrijskih svojstava (slika 2).Standardna deskriptivna statistika (prosječna vrijednost, min/max vrijednost, raspon varijacije, standardna devijacija, relativna standardna devijacija), analiza varijance (one way ANOVA), post hoc Tukey HSD test i klaster analiza (metoda najbližeg susjeda, Euklidska udaljenost) su provedeni kako bi se utvrdile razlike na unutarpopulacijskom i međupopulacijskoj razini.Rezultati analize varijance (tabela 2.) ukazuju na postojanje statistički značajnih razlika između individua u okviru populacija za sva ispitivana morfometrijska svojstva (p<0,000). Dok su rezultati analize varijance provedeni radi utvrđivanja značajnosti razlika između populacija pokazali da za svojstva b, d, f, h i i postoji statistički značajna razlika između populacija. Tukey testom i klaster analizom utvrđeno je da se populacija A najviše ističe, potom slijedi populacija C, dok su populacije B i D najsličnije. Rezultati analiza pokazuju izraženu varijabilnost kada su u pitanju parametri c, e, f i d za koje se smatra da su pod izrazitom genetskom kontrolom, dok parametri b, a i g koji se odlikuju velikom plastičnošću pokazuju manju varijabilnost, što ukazuje na slične stanišne uvjete istraživanih populacija.Dobijene statističke analize ukazale su da na unutarpopulacijskoj i međupopulacijskoj razini postoji značajna varijabilnost, pri čemu je varijabilnost unutar populacija dosta izraženija od varijabilnosti između populacija. Imajući u vidu da su stanišni uvijeti istraživanih populacija ujednačeni i na osnovi utvrđenih statističkih značajnosti može se zaključiti da su njihove razlike zanemarive, možemo zaključiti da je unutarpopulacijska različitost uzrokovana izrazitom heterogenošću analiziranih genotipova ovih populacija

Prikaz knjige Dr Fred Newman i dr Phyllis Goldberg: Vodič za stalni lični rast i razvoj – Let’s Develop!

UDK 159.947.3(049.32); 615.862(049.32

Prikaz knjige Bojana Škorc: Kreativnost u interakciji – Psihologija stvaralaštva

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