Select-divide-and-conquer method for large-scale configuration interaction

A select-divide-and-conquer variational method to approximate configuration interaction (CI) is presented. Given an orthonormal set made up of occupied orbitals (Hartree-Fock or similar) and suitable correlation orbitals (natural or localized orbitals), a large N-electron target space S is split into subspaces S0,S1,S2,...,SR. S0, of dimension d0, contains all configurations K with attributes (energy contributions, etc.) above thresholds T0={T0egy, T0etc.}; the CI coefficients in S0 remain always free to vary. S1 accommodates KS with attributes above T1≤T0. An eigenproblem of dimension d0+d1 for S0+S 1 is solved first, after which the last d1 rows and columns are contracted into a single row and column, thus freezing the last d1 CI coefficients hereinafter. The process is repeated with successive Sj(j≥2) chosen so that corresponding CI matrices fit random access memory (RAM). Davidson's eigensolver is used R times. The final energy eigenvalue (lowest or excited one) is always above the corresponding exact eigenvalue in S. Threshold values {Tj;j=0, 1, 2,...,R} regulate accuracy; for large-dimensional S, high accuracy requires S 0+S1 to be solved outside RAM. From there on, however, usually a few Davidson iterations in RAM are needed for each step, so that Hamiltonian matrix-element evaluation becomes rate determining. One μhartree accuracy is achieved for an eigenproblem of order 24 × 106, involving 1.2 × 1012 nonzero matrix elements, and 8.4×109 Slater determinants

A tool for replay and analysis of gaze-enhanced multiparty sessions captured in immersive collaborative environments

A desktop tool for replay and analysis of gaze-enhanced multiparty virtual collaborative sessions is described. We linked three CAVE (TM)-like environments, creating a multiparty collaborative virtual space where avatars are animated with 3D gaze as well as head and hand motions in real time. Log files are recorded for subsequent playback and analysis Using the proposed software tool. During replaying the user can rotate the viewpoint and navigate in the simulated 3D scene. The playback mechanism relies on multiple distributed log files captured at every site. This structure enables an observer to experience latencies of movement and information transfer for every site as this is important fir conversation analysis. Playback uses an event-replay algorithm, modified to allow fast traversal of the scene by selective rendering of nodes, and to simulate fast random access. The tool's is analysis module can show each participant's 3D gaze points and areas where gaze has been concentrated.

Optimising memory usage in n-tuple neural networks

The use of n-tuple or weightless neural networks as pattern recognition devices is well known (Aleksander and Stonham, 1979). They have some significant advantages over the more common and biologically plausible networks, such as multi-layer perceptrons; for example, n-tuple networks have been used for a variety of tasks, the most popular being real-time pattern recognition, and they can be implemented easily in hardware as they use standard random access memories. In operation, a series of images of an object are shown to the network, each being processed suitably and effectively stored in a memory called a discriminator. Then, when another image is shown to the system, it is processed in a similar manner and the system reports whether it recognises the image; is the image sufficiently similar to one already taught? If the system is to be able to recognise and discriminate between m-objects, then it must contain m-discriminators. This can require a great deal of memory. This paper describes various ways in which memory requirements can be reduced, including a novel method for multiple discriminator n-tuple networks used for pattern recognition. By using this method, the memory normally required to handle m-objects can be used to recognise and discriminate between 2^m — 2 objects.

Auto-associative memory using n-tuple techniques

The use of n-tuple or weightless neural networks as pattern recognition devices has been well documented. They have a significant advantages over more common networks paradigms, such as the multilayer perceptron in that they can be easily implemented in digital hardware using standard random access memories. To date, n-tuple networks have predominantly been used as fast pattern classification devices. The paper describes how n-tuple techniques can be used in the hardware implementation of a general auto-associative network.

Electric and dielectric behavior of CaCu3Ti4O12-based thin films obtained by soft chemical method

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gestão Sustentável da água: um estudo da conscientização ambiental em atividades residenciais urbanas

The search for sustainable solutions through an appropriate environmental administration of the available natural resources, that comes from encounter to the aspirations of preservation of the environment and of the human being, in way to diagnose and to solve the environmental and social problems with the smallest possible impact to the nature and the man, it is the great challenge, so much for that generation, as for the future generations. The study of the environmental problems of the water and the participation and the social actors' environmental understanding as a whole, interferes in the field of the thematic environmental international, contemplating the strategic need of an appropriate administration of that very natural one, through a program returned to the diagnosis of the problems and in the search of compatible maintainable solutions, in a social and environmental politics of planning and environmental education, centered above all in the citizen's voice , user of that system. The present thesis she seeks to study the problem of the maintainable administration of the water, focusing the participation and the citizen's environmental understanding in the use of that very natural one for urban residential activities, in what concerns the approach and analyses of variables that treat of the measurement of general knowledge and you adapt, sense of community of the access to the means of information and of the attitudes and environmental behaviors, besides the variables of partner-demographic characterization or personal identification of the interviewed ones of an exploratory research of the type " survey ", accomplished through a stratified aleatory sampling, being the strata each one of the 4 (four) Political-Administrative Areas of the Natal city, having happened the collection of the data in the period of february to april/2002. The methodology used in this work it constitutes in the application of questionnaires with scales of the type Likert to measure the echo-varied of the study, besides a partner-demographic scale for the characterization of the studied sample. For the analysis of the results, it was made an exploratory descriptive study initially, followed by the use of techniques statistical multivariate s, such as, factorial analysis through the application of main components, besides the accomplishment of studies of multiple lineal regression. To complement this study, the accomplishment of Tests of Independence was proceeded through the Qui-square of Pearson, in way to verify the dependence of the associations between the partner-demographic variables and the principal selected variables and presents in the resulting factors of the factorial analysis. The results appear for a low level of environmental knowledge, of access to the information and community's sense, besides the verification that the principal factors resultants send for the need of feeling emphasis in the programs and administration actions addressed for the environmental understanding, the behaviors and attitudes that approach the information and the environmental education, besides the reuse of the water

Dielectric and fatigue properties of Pb(Zr0.53Ti0.47)O-3 thin films prepared from oxide precursors method

Fatigue is an important problem to be considered if a ferroelectric film is used for non-volatile memory devices. In this phenomena, the remanent polarization and coercive field properties degrades in cycles which increase in hysteresis loops. The reasons have been attributed to different mechanisms such as a large voltage applied on ferroelectric film in every reading process in Ferroelectric Random Access Memory (FeRAM) or memories for digital storage in computer, grain size effects and others. The aim of this work is to investigate the influence of the crystallization kinetics on dielectric and ferroelectric properties of the Pb(Zr0.53Ti0.47)O-3 thin films prepared by an alternative chemical method. Films were crystallized in air on Pt/Ti/SiO2/Si substrates at 700 degrees C for 1 hour, in conventional thermal annealing (CTA), and at 700 degrees C for 1 min and 700 degrees C 5 min, using a rapid thermal annealing (RTA) process. Final films were crack free and presented an average of 750 nm in thickness. Dielectric properties were studied in the frequency range of 100 Hz - 1 MHz. All films showed a dielectric dispersion at low frequency. Ferroelectric properties were measured from hysteresis loops at 10 kHz. The obtained remanent polarization (P-r) and coercive field (E-c) were 3.7 mu C/cm(2) and 71.9 kV/cm respectively for film crystallized by CTA while in films crystallized by RTA these parameters were essentially the same. In the fatigue process, the P, value decreased to 14% from the initial value after 1.3 x 10(9) switching cycles, for film by CTA, while for film crystallized by RTA for 5 min, P, decreased to 47% from initial value after 1.7 x 10(9) switching cycles.

An active leakage-injection scheme applied to low-voltage SRAMs

An active leakage-injection scheme (ALIS) for low-voltage (LV) high-density (HD) SRAMs is presented. By means of a feedback loop comprising a servo-amplifier and a common-drain MOSFET, a current matching the respective bit-line leakage is injected onto the line during precharge and sensing, preventing the respective capacitances from erroneous discharges. The technique is able to handle leakages up to hundreds of μA at high operating temperatures. Since no additional timing is required, read-out operations are performed at no speed penalty. A simplified 256×1bit array was designed in accordance with a 0.35 CMOS process and 1.2V-supply. A range of PSPICE simulation attests the efficacy of ALIS. With an extra power consumption of 242 μW, a 200 μA-leakage @125°C, corresponding to 13.6 times the cell current, is compensated.

Microscopic and dielectric analyses of vanadium and tungsten modified barium zirconium titanate ceramics

Dielectric spectroscopy was used in this study to examine polycrystalline vanadium and tungstendoped BaZr 0.1Ti 0.90O 3 (BZT10:2V and BZT10:2W) ceramics obtained by the mixed oxide method. According to X-ray diffraction analyses, addition of vanadium and tungsten lead to ceramics free of secondary phases. SEM analyses reveal that both dopants result in slower oxygen ion motion and consequently lower grain growth rate. Temperature dependence dielectric study showed normal ferroelectric to paraelectric transition well above the room temperature for the BZT10 and BZT10:2V ceramics. However, BZT10:2W ceramic showed a relaxor-like behavior near phase transition characterized by the empirical parameter γ. Piezoelectric force microscopy images reveals that the piezoelectric coefficient is strongly influenced by type of donor dopant suggesting promising applications for dynamic random access memories and data-storage media. Copyright © 2010 American Scientific Publishers All rights reserved.

Typology of instruments of public environmental international law

At the second meeting of the focal points appointed by the Governments of the signatory countries of the Declaration on the application of Principle 10 of the Rio Declaration on Environment and Development in Latin America and the Caribbean, which was held in Guadalajara, Mexico, on 16 and 17 April 2013, a decision was made to form working groups to advance towards the creation of a regional instrument. Thus, a working group on access rights and the regional instrument was formed for the purpose of gaining more in-depth knowledge on access rights in order to make a proposal on the nature and scope of the application of a regional instrument. At its first meeting, the working group determined that a study describing the different types of international instruments would be useful in helping it achieve its objective. This report explores the different types of instruments that are used in public international law, with an emphasis on the instruments that are relevant to Principle 10. The report has three chapters, which are as follows. The first chapter analyses the term “international instrument” and discusses the distinction between binding and non-binding legal instruments, illustrated with examples. The second chapter describes the function of implementation and compliance mechanisms in an international instrument, providing examples of these mechanisms. The third chapter presents the multilateral and regional instruments relevant to access rights regarding information, participation and justice in environmental matters in Latin America and the Caribbean.

Avaliação da freqüência cardíaca nas atividades de colheita de Eucalipto, utilizando a motosserra, como fator para a determinação de pausas adequadas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Preparação e caracterização de filmes finos de 'BA''BI IND.2''TA IND.2''O IND.9(BBT)' e 'BA''BI IND.2''NB IND.2''O IND.9(BBN)'

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Novel Fiber Delay Line Buffering Architecture for Optical Packet Switching

Due to the lack of optical random access memory, optical fiber delay line (FDL) is currently the only way to implement optical buffering. Feed-forward and feedback are two kinds of FDL structures in optical buffering. Both have advantages and disadvantages. In this paper, we propose a more effective hybrid FDL architecture that combines the merits of both schemes. The core of this switch is the arrayed waveguide grating (AWG) and the tunable wavelength converter (TWC). It requires smaller optical device sizes and fewer wavelengths and has less noise than feedback architecture. At the same time, it can facilitate preemptive priority routing which feed-forward architecture cannot support. Our numerical results show that the new switch architecture significantly reduces packet loss probability.

Junction Field Effect on the Retention Time for One-Transistor Floating-Body RAM

One-transistor floating-body random access memory retention time distribution is investigated on silicon-on-insulator UTBOX devices. It is shown that the average retention time can be improved by two to three orders of magnitude by reducing the body-junction electric field. However, the retention time distribution, which is mainly caused by the generation-recombination center density variation, remains similar.

Dependence of Generation-Recombination Noise With Gate Voltage in FD SOI MOSFETs

A model for computing the generation-recombination noise due to traps within the semiconductor film of fully depleted silicon-on-insulator MOSFET transistors is presented. Dependence of the corner frequency of the Lorentzian spectra on the gate voltage is addressed in this paper, which is different to the constant behavior expected for bulk transistors. The shift in the corner frequency makes the characterization process easier. It helps to identify the energy position, capture cross sections, and densities of the traps. This characterization task is carried out considering noise measurements of two different candidate structures for single-transistor dynamic random access memory devices.