159 resultados para oriented line patterns
Resumo:
The problem of automatic melody line identification in a MIDI file plays an important role towards taking QBH systems to the next level. We present here, a novel algorithm to identify the melody line in a polyphonic MIDI file. A note pruning and track/channel ranking method is used to identify the melody line. We use results from musicology to derive certain simple heuristics for the note pruning stage. This helps in the robustness of the algorithm, by way of discarding "spurious" notes. A ranking based on the melodic information in each track/channel enables us to choose the melody line accurately. Our algorithm makes no assumption about MIDI performer specific parameters, is simple and achieves an accuracy of 97% in identifying the melody line correctly. This algorithm is currently being used by us in a QBH system built in our lab.
Resumo:
We consider the problem of detecting statistically significant sequential patterns in multineuronal spike trains. These patterns are characterized by ordered sequences of spikes from different neurons with specific delays between spikes. We have previously proposed a data-mining scheme to efficiently discover such patterns, which occur often enough in the data. Here we propose a method to determine the statistical significance of such repeating patterns. The novelty of our approach is that we use a compound null hypothesis that not only includes models of independent neurons but also models where neurons have weak dependencies. The strength of interaction among the neurons is represented in terms of certain pair-wise conditional probabilities. We specify our null hypothesis by putting an upper bound on all such conditional probabilities. We construct a probabilistic model that captures the counting process and use this to derive a test of significance for rejecting such a compound null hypothesis. The structure of our null hypothesis also allows us to rank-order different significant patterns. We illustrate the effectiveness of our approach using spike trains generated with a simulator.
Resumo:
In the title compound, C30H24Cl2N2O3, the two quinoline ring systems are almost planar [maximum deviations = 0.029 (2) and 0.018 (3) angstrom] and the dihedral angle between them is 4.17 (8)degrees. The dihedral angle between the phenyl ring and its attached quinoline ring is 69.06 (13)degrees. The packing is stabilized by C-H center dot center dot center dot O, C-H center dot center dot center dot N, weak pi-pi stacking [centroid-centroid distances = 3.7985 (16) and 3.7662(17) angstrom] and C-H center dot center dot center dot pi interactions.
Resumo:
A novel PBG cell based on micromachining of Silicon using wet anisotropic etching has been considered. Since this is based on etching of the Silicon substrate, it is amenable to fabrication with standard Silicon processes and integration with millimeter wave circuits. We characterize this kind of PBG cell by full wave simulations using a time domain code. For the purpose of characterization, the scenario of a 50 ohm microstrip line placed on a Silicon substrate which is anisotropically etched to create patterns with sloping walls is considered. This is shown to produce the well known PBG response of stop bands in certain frequency bands. We look at the variation in the transmission coefficient (S-21) response as the number of periods, length based average fill factor and depth of micromachining are varied. One application of a low pass filter has been proposed and simulated results are given.
Resumo:
Evaluation and design of shore protection works in the case of tsunamis assumes considerable importance in view of the impact it had in the recent tsunami of 26th December 2004 in India and other countries in Asia. The fact that there are no proper guidelines have made in the matters worse and resulted in the magnitude of damage that occurred. Survey of the damages indicated that the scour as a result of high velocities is one of the prime reasons for damages in the case of simple structures. It is revealed that sea walls in some cases have been helpful to minimize the damages. The objective of this paper is to suggest that design of shore line protection systems using expected wave heights that get generated and use of flexible systems such as geocells is likely to give a better protection. The protection systems can be designed to withstand the wave forces that corresponding to different probabilities of incidence. A design approach of geocells protection system is suggested and illustrated with reference to the data of wave heights in the east coast of India.
Resumo:
At the time of restoration transmission line switching is one of the major causes, which creates transient overvoltages. Though detailed Electro Magnetic Transient studies are carried out extensively for the planning and design of transmission systems, such studies are not common in a day-today operation of power systems. However it is important for the operator to ensure during restoration of supply that peak overvoltages resulting from the switching operations are well within safe limits. This paper presents a support vector machine approach to classify the various cases of line energization in the category of safe or unsafe based upon the peak value of overvoltage at the receiving end of line. Operator can define the threshold value of voltage to assign the data pattern in either of the class. For illustration of proposed approach the power system used for switching transient peak overvoltages tests is a 400 kV equivalent system of an Indian southern gri
Resumo:
Separated local field (SLF) spectroscopy is a powerful technique to measure heteronuclear dipolar couplings. The method provides site-specific dipolar couplings for oriented samples such as membrane proteins oriented in lipid bilayers and liquid crystals. A majority of the SLF techniques utilize the well-known Polarization Inversion Spin Exchange at Magic Angle (PISEMA) pulse scheme which employs spin exchange at the magic angle under Hartmann-Hahn match. Though PISEMA provides a relatively large scaling factor for the heteronuclear dipolar coupling and a better resolution along the dipolar dimension, it has a few shortcomings. One of the major problems with PISEMA is that the sequence is very much sensitive to proton carrier offset and the measured dipolar coupling changes dramatically with the change in the carrier frequency. The study presented here focuses on modified PISEMA sequences which are relatively insensitive to proton offsets over a large range. In the proposed sequences, the proton magnetization is cycled through two quadrants while the effective field is cycled through either two or four quadrants. The modified sequences have been named as 2(n)-SEMA where n represents the number of quadrants the effective field is cycled through. Experiments carried out on a liquid crystal and a single crystal of a model peptide demonstrate the usefulness of the modified sequences. A systematic study under various offsets and Hartmann-Hahn mismatch conditions has been carried out and the performance is compared with PISEMA under similar conditions.
Resumo:
As is well known, when monochromatic light scattered by a liquid is examined under high resolution it exhibits a fine structure: an undisplaced central line and two lines on either side with wavelengths slightly different from that of the incident light. The appearance of the displaced components was first predicted by Brillouin1. On the basis of his theory, the observed displacements of frequency are regarded as a Doppler effect arising from the reflexion of the light wave by the progressive sound waves of thermal origin in the scattering medium. The frequency shift of the so-called Brillouin components is given by the formula where nu and c are the velocities of sound and light in the medium and theta is the angle of scattering. That the effect contemplated by Brillouin does arise in liquids and crystals is now a well-established experimental fact.
Resumo:
A detailed investigation of the natural frequencies and mode shapes of simply supported symmetric trapezoidal plates is undertaken in this paper. For numerical calculations, the relationship that exists between the eigenvalue problem of a polygonal simply supported plate and the eigenvalue problem of polygonal membrane of the same shape is utilized with advantage. The deflection surface is expressed in terms of a Fourier sine series in transformed coordinates and the Galerkin method is used. Results are presented in the form of tables and graphs. Several features like the crossing of frequency curves and the metamorphosis of some of the nodal patterns are observed. By a suitable interpretation of the modes of those symmetric trapezoidal plates which have the median as the nodal line, the results for some of the modes of unsymmetrical trapezoidal plates are also deduced.
Resumo:
The line spectral frequency (LSF) of a causal finite length sequence is a frequency at which the spectrum of the sequence annihilates or the magnitude spectrum has a spectral null. A causal finite-length sequencewith (L + 1) samples having exactly L-LSFs, is referred as an Annihilating (AH) sequence. Using some spectral properties of finite-length sequences, and some model parameters, we develop spectral decomposition structures, which are used to translate any finite-length sequence to an equivalent set of AH-sequences defined by LSFs and some complex constants. This alternate representation format of any finite-length sequence is referred as its LSF-Model. For a finite-length sequence, one can obtain multiple LSF-Models by varying the model parameters. The LSF-Model, in time domain can be used to synthesize any arbitrary causal finite-length sequence in terms of its characteristic AH-sequences. In the frequency domain, the LSF-Model can be used to obtain the spectral samples of the sequence as a linear combination of spectra of its characteristic AH-sequences. We also summarize the utility of the LSF-Model in practical discrete signal processing systems.
Resumo:
The variety of electron diffraction patterns arising from the decagonal phase has been explored using a stereographic analysis for generating the important zone axes as intersection points corresponding to important relvectors. An indexing scheme employing a set of five vectors and an orthogonal vector has been followed. A systematic tilting from the decagonal axis to one of the twofold axes has been adopted to generate a set of experimental diffraction patterns corresponding to the expected patterns from the stereographic analysis with excellent agreement.
Resumo:
CMPs enable simultaneous execution of multiple applications on the same platforms that share cache resources. Diversity in the cache access patterns of these simultaneously executing applications can potentially trigger inter-application interference, leading to cache pollution. Whereas a large cache can ameliorate this problem, the issues of larger power consumption with increasing cache size, amplified at sub-100nm technologies, makes this solution prohibitive. In this paper in order to address the issues relating to power-aware performance of caches, we propose a caching structure that addresses the following: 1. Definition of application-specific cache partitions as an aggregation of caching units (molecules). The parameters of each molecule namely size, associativity and line size are chosen so that the power consumed by it and access time are optimal for the given technology. 2. Application-Specific resizing of cache partitions with variable and adaptive associativity per cache line, way size and variable line size. 3. A replacement policy that is transparent to the partition in terms of size, heterogeneity in associativity and line size. Through simulation studies we establish the superiority of molecular cache (caches built as aggregations of molecules) that offers a 29% power advantage over that of an equivalently performing traditional cache.
Resumo:
n many parts of the world, the goal of electricity supply industries is always the introduction of competition and a lowering of the average consumer price. Because of this it has become much more important to be able to determine which generators are supplying a particular load, how much use each generator is making of a transmission line and what is generator's contribution to the system losses. In this paper a case study on generator contributions towards loads and transmission flows are illustrated with an equivalent 11-bus system, a part of Indian Southern Grid, based on the concepts of circuit flow directions, for normal and network contingency conditions.
Resumo:
By carrying out the reaction of appropriate metal compounds with Na2S in the presence of a tripodal cholamide-based hydrogel, nanotubes and nanorods of CdS, ZnS and CuS have been obtained. The nanostructures have been characterized by transmission electron microscopy and spectroscopic techniques. Evidence is presented for the assembly of short nanorods to form one-dimensional chains.
Resumo:
using two types of organic ligands having similar chemical structure but different physical properties and varying their dynamic population at the surface of zinc blende seed nanocrystals, self-assembled zinc blende semicircular-shaped bent nanowires of CdS are synthesized via a colloidal synthetic approach. It is found that the hydrophobic tail interaction of long-chain ligands puts strain on these thin nanowires (< 2 nm diameter) and bend them to some extent, forming strained nanowires.