STUDY ON PHASE PERCEPTION IN SPEECH

The perceptual effect of the phase information in speech has been studied by auditory subjective tests. On the condition that the phase spectrum in speech is changed while amplitude spectrum is unchanged, the tests show that: (1) If the envelop of the reconstructed speech signal is unchanged, there is indistinctive auditory perception between the original speech and the reconstructed speech; (2) The auditory perception effect of the reconstructed speech mainly lies on the amplitude of the derivative of the additive phase; (3) td is the maximum relative time shift between different frequency components of the reconstructed speech signal. The speech quality is excellent while td <10ms; good while 10ms< td <20ms; common while 20ms< td <35ms, and poor while td >35ms.     

Microstructural and textural characterization of a hot-rolled IF steel

The present paper reports the experimental results on the microstructural and textural characterization of a hot-rolled IF steel. The IF steel was hot-rolled in multiple passes in the austenitic field (1,070 °C) followed by air-cooling. SEM, TEM, and LOM were used to image the microstructure of the material. The global texture was determined by X-ray diffraction (XRD) technique. The mesotexture of selected regions was investigated by electron backscatter diffraction (EBSD). Results show the presence of a diffuse (nearly random) and weak texture in the hot-band that consists of recrystallized polygonal grains and subgrains. The fraction of boundaries with misorientations comprised in the interval 2° ≤ ψ < 15° was found to be lower than 5%. It can be concluded that these low angle boundaries and the presence of subgrains can be associated to the existence of a few areas softened by recovery during or after hot rolling in austenitic field.     

Effect of hydrogen charging on dislocation behavior in Ni-Cr and Ni<Subscript>2</Subscript>Cr alloys

The effects of hydrogen charging on the dislocation behaviour in Ni-Cr binary alloys have been investigated by means of transmission electron microscope (TEM) observations using single-crystalline specimens. The deformation mode of Ni-Cr alloys in the absence of hydrogen is characterized by planar dislocations. However, hydrogen charging changed the dislocation configurations to promote curved dislocations, such as dislocation loops and dipoles. The hydrogen-affected dislocation configurations are enhanced with increasing Ni content and reducing Cr content. Weak-beam images show that the Shockley partials of the hydrogen-affected dislocations frequently constrict to make kinks and cross-slip, as if the dislocations were generated by a thermally activated process. The effect of hydrogen charging on superdislocations of a Ni₂Cr superstructure has been also investigated using an aged 70Ni-30Cr alloy. While the deformation mode in the Ni₂Cr superlattice is classified as five variants of superdislocation triplets and one variant of ordinary dislocations, the hydrogen charging has preferred the ordinary dislocations to the superdislocation triplets. The results suggest that the charged hydrogen changes the local plasticity to affect the deformation dynamics in Ni-Cr alloys, where the influence of hydrogen on the plasticity is sensitive to the Ni/Cr concentration and the symmetry of atomic arrangement.     

Bayesian and Dempster-Shafer fusion

The Kalman Filter is traditionally viewed as a prediction-correction filtering algorithm. In this work we show that it can be viewed as a Bayesian fusion algorithm and derive it using Bayesian arguments. We begin with an outline of Bayes theory, using it to discuss well-known quantities such as priors, likelihood and posteriors, and we provide the basic Bayesian fusion equation. We derive the Kalman Filter from this equation using a novel method to evaluate the Chapman-Kolmogorov prediction integral. We then use the theory to fuse data from multiple sensors. Vying with this approach is the Dempster-Shafer theory, which deals with measures of “belief”, and is based on the nonclassical idea of “mass” as opposed to probability. Although these two measures look very similar, there are some differences. We point them out through outlining the ideas of the Dempster-Shafer theory and presenting the basic Dempster-Shafer fusion equation. Finally we compare the two methods, and discuss the relative merits and demerits using an illustrative example.     

Web-based systems design: a study of contemporary practices and an explanatory framework based on “method-in-action”

This paper reports the findings of a detailed study of Web-based systems design (WBSD) practices in Ireland based on data collected over a 3-year period (2002–2005), the objectives of which were to (1) contribute towards a richer understanding of the current “real-world” context of WBSD by characterising the profile of a typical project (team size, timeframe, nature of requirements, etc.) and identifying the key challenges, constraints, and imperatives (i.e. “mediating factors”) faced by Web-based system designers, and (2) understand how those contextual parameters and mediating factors influence the activity of WBSD as regards the selection and enactment of whatever design practices are therefore engaged (i.e. the use of methods, procedures, etc.). Data was gathered through a survey which yielded 165 usable responses, and later through a series of semi-structured qualitative interviews. Using grounded theory, an explanatory conceptual framework is derived, based on an extension of the “method-in-action” model, the application of which to WBSD has not been previously investigated in depth. It is proposed that this framework of WBSD issues is valuable in a number of ways to educators, researchers, practitioners, and method engineers.     

Equivalent Conditions for Convergence of Splittings of Non-Hermitian Indefinite Matrices

We present some sufficient and necessary conditions for convergent splitting of a non-Hermitian indefinite matrix. Some sufficient conditions to determinate a matrix with a (strongly) dominant symmetric part for a class of boundary value problem are also obtained. These results are applicable to identify the convergence of iterative methods for solving large sparse systems of linear equations.     

Evaluation of intraductal ultrasonography in the diagnosis of pancreatic cancer

An intraductal ultrasound (IDUS) probe which is inserted via the papilla into the main pancreatic duct (MPD) was evaluated in the diagnosis of 20 patients with pancreatic cancer. The examination was successfully performed with the probe in 17 of the patients (85%). Due to its high frequency (30 MHz) the probe only allowed visualization of the ductal wall and the immediate periductal vicinity (up to about 10 mm). In 15 of the 20 patients the tumors were surgically resected and IDUS scanning was also performed in vitro on the resection specimens, the results being compared to those of histopathological examination. Of these 15 patients, 13 were found to have ductal adenocarcinomas and all but one had been unequivocally diagnosed as having such by ultrasonography (US), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasonography (EUS). IDUS showed an echorich area (corresponding to cancerous canaliculi on histopathological examination), surrounded by an echopoor area (abundant stroma). This pattern was classified as type I. In two patients with intraductal papillary carcinomas in whom a conclusive diagnosis was not established on US, CT, EUS or ERCP, IDUS showed tumorous tissue with an inhomogeneous echopattern outside (type II) or within (type III) the duct. These results show that IDUS offers valuable diagnostic information complementary to ERCP especially in cases of intraductal papillary tumors. Whether the high resolution imaging of the duct and the paraductal tissue can be used to differentiate between the different forms of pancreatic lesions (inflammation, neoplasms) has to be investigated further.     

Immunochemical characterization of anti-H monoclonal antibodies obtained from a mouse immunized with human saliva

Three IgM class anti-H monoclonal antibodies (1E3, 1E5 and 3H1) were obtained from a BALB/c mouse immunized with human O type saliva. These antibodies were found to agglutinate red cells from O group and A and B subgroups but not from Bombay and para-Bombay individuals whose H antigen was barely detected by anti-H reagents. The agglutination reactions of these antibodies were inhibited by H antigens from human tissues. It was also demonstrated that both 1E3 and 3H1 reacted with H disaccharide (Fuc alpha 1-->2Gal beta), H type 1 (Fuc alpha 1-->2Gal beta 1-->3GlcNAc beta), H type 2 (Fuc alpha 1-->2Gal beta 1-->4GlcNAc beta), H type 3 (Fuc alpha 1-->2Gal beta 1-->3GalNAc alpha) and H type 4 (Fuc alpha 1-->2Gal beta 1-->3GalNAc beta) but not with Lea (Gal beta 1-->3[Fuc alpha 1-->4]GlcNAc beta), Leb (Fuc alpha 1-->2Gal beta 1-->3[Fuc alpha 1-->4]GlcNAc beta), X (Gal beta 1-->4[Fuc alpha-->3]GlcNAc beta) or Y (Fuc alpha 1-->2Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc beta). On the other hand, 1E5 was found to react with H type 1, H type 2, Leb and Y. Because of the unique reactivities against various fucosyl linkages these monoclonal antibodies could be useful not only as anti-H reagents but also as reagents for the structural analysis of fucosylated glycoconjugates.