Pitch Estimation by Block and Instantaneous Methods

Choosing a pitch estimation algorithm is not a simple task. One must balance between the accuracy and the reliability of the estimates. Two classes of methods are available. The first one, known as the block methods class, gives noise robust solutions and has an intrinsic averaging property, but is not very accurate, especially for the transition regions. The second one, known as the instantaneous (or event-based) methods class, gives very accurate estimates, but is considered to be inadequate in the presence of noise.In this paper, we present potential enhancements of the performance in pitch estimation, based on both block and instantaneous methods. In this respect we discuss mainly two algorithms: a nonlinear cepstral algorithm and a wavelet-based one. The first algorithm, due to the proposed nonlinear model, enhances the classical linear model performance related to the accuracy of the estimated pitch for the transition regions and to the robustness in the presence of noise. Concerning the second algorithm, to the inherent accuracy of the estimated pitch, we add robust estimates even in the presence of noise, based on the multiresolution properties of an improved wavelet transform. The obtained enhancements were evaluated on a hand-labeled speech database, and the improved algorithms are now being applied in our research concerning speech compression and prosody.     

Surveyance of disease frequency in a population by linkage to diagnostic laboratory databases. A system for monitoring the incidences of hyper- and hypothyroidism as part of the Danish iodine supplementation program

In Denmark an increase in iodine intake through salt iodization has been introduced in 1998. In parallel a program for surveyance of thyroid diseases in the population was developed as recommended by UNICEF and WHO. OBJECTIVE: To develop and evaluate a computer based system to identify and register new cases of hyper- and hypothyroidism in a well defined cohort, by linkage to diagnostic laboratory databases. DESIGN AND RESULTS: (1) Two sub cohorts for monitoring were defined (n=535,859), and evaluated to minimize loss of new cases. Collaboration was established with laboratories covering thyroid hormone analyses in the cohort; (2) a diagnostic algorithm was defined and evaluated against clinical practice; (3) evaluation of the laboratory methods employed by the four participating laboratories, to ensure they would reach the same diagnosis in a patient; (4) a register database was developed which used data imported from the laboratory databases to automatically identify previously unknown cases of hyper- and hypothyroidism and record diagnostic activity in the area. All parts of the registration were carefully evaluated. CONCLUSION: We describe for the first time a computer based system for prospective measuring the incidence rate of hyper- and hypothyroidism. The system is particularly useful for monitoring of iodine supplementation programmes.     

Investigation of prandial effects on hydrophilic matrix tablets.

The prolonged release of drug from hydrophilic matrix tablets can be greatly affected by administration in connection with the intake of food. Changes of the tablet erosion are one of the main components of this effect. The aim of the present study was to identify the postprandial factors responsible for changes in tablet erosion and to develop predictive in vitro tests. Two formulations, one sensitive and the other robust to prandial effects in vivo, were investigated in vitro (a) in a complex physiological media simulating fasting and fed conditions; (b) according to a factorial experimental design that included agitation and pH concentrations of salt, surface-active agent, and nonionic solute as factors; and (c) at varying agitation intensities in three different sets of dissolution apparatus. Of the studied factors, only increased agitation enhanced the erosion of tablets in accordance with the in vivo effects of a meal. The other factors retarded erosion or had only minor effects. The hydrodynamic mechanical stress was thus considered to be the main factor responsible for postprandial effects on tablet erosion. The influence of changes in agitation and the opportunity to discriminate between sensitive and robust formulations differed among the three sets of dissolution apparatus. The modified USP II apparatus, operated at speeds of 50 and 100 rpm, is proposed as a discriminatory test.     

Shape "break-and-repair" strategy and its application to automated medical image segmentation

In three-dimensional medical imaging, segmentation of specific anatomy structure is often a preprocessing step for computer-aided detection/diagnosis (CAD) purposes, and its performance has a significant impact on diagnosis of diseases as well as objective quantitative assessment of therapeutic efficacy. However, the existence of various diseases, image noise or artifacts, and individual anatomical variety generally impose a challenge for accurate segmentation of specific structures. To address these problems, a shape analysis strategy termed "break-and-repair" is presented in this study to facilitate automated medical image segmentation. Similar to surface approximation using a limited number of control points, the basic idea is to remove problematic regions and then estimate a smooth and complete surface shape by representing the remaining regions with high fidelity as an implicit function. The innovation of this shape analysis strategy is the capability of solving challenging medical image segmentation problems in a unified framework, regardless of the variability of anatomical structures in question. In our implementation, principal curvature analysis is used to identify and remove the problematic regions and radial basis function (RBF) based implicit surface fitting is used to achieve a closed (or complete) surface boundary. The feasibility and performance of this strategy are demonstrated by applying it to automated segmentation of two completely different anatomical structures depicted on CT examinations, namely human lungs and pulmonary nodules. Our quantitative experiments on a large number of clinical CT examinations collected from different sources demonstrate the accuracy, robustness, and generality of the shape "break-and-repair" strategy in medical image segmentation.     

SUPRENUM software for the symmetric eigenvalue problem

The effecient use of the SUPRENUM computer calls for a careful choice of adequate algorithms and an implementation taking into account the special characteristics of a parallel computer with distributed memory. To demonstrate these facts, well-known algorithms solving the symmetric eigenvalue problem are presented, parallelized in particular for the SUPRENUM machine.

The main problems arise in the amount of communication calls, and ways are shown to reduce this amount by using block algorithms rather than the usual ones.     

Some conclusions with regard to the safety assessment of cracked components drawn from the research programme “integrity of components” (FKS II) atthe present state

The continuation of the research program “Integrity of Components”, Phase II, mainly deals with further evaluation and assessment of material properties and the application of data from small standard specimens to large scale specimens and components. This includes the use of advanced numerical methods to check the transferability of fracture mechanics parameters with regard to the type of load and degree of multiaxiality on the failure behaviour of fracture mechanics specimens with component-like dimensions. Further points of interest are the relationship between upper shelf toughness and load-bearing capacity, the influence of neutron irradiation on the properties, and the effect of corrosion on cyclic crack growth.     

Sex roles and social support as moderators of life stress adjustment.

In this study we used a longitudinal design to test the stress-buffering effects of sex role orientation in combination with perceived social support on measure of trait anxiety and depression. College undergraduates served as subjects. The cross-sectional analysis provided strong support for the hypothesis that masculinity would function as a life stress buffer. The hypothesis that social support would serve as a stress buffer when coupled with high masculinity was supported by one of the cross-sectional analyses as well as the longitudinal analysis. This pattern was found primarily for perceptions of tangible social support. The longitudinal analysis also revealed a significant interaction involving negative life events and masculinity and femininity. This interaction effect provided unexpected support for a balance model of androgyny, in that non-sex-typed subjects showed greater resilience to recent life stress than did sex-typed subjects. The findings are discussed in terms of their implications for the study of life stress adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sufficient Conditions for Uniform Convergence on Layer-Adapted Grids

We study convergence properties of the simple upwind difference scheme and a Galerkin finite element method on generalized Shishkin grids. We derive conditions on the mesh-characterizing function that are sufficient for the convergence of the method, uniformly with respect to the perturbation parameter. These conditions are easy to check and enable one to immediately deduce the rate of convergence. Numerical experiments support these theoretical results and indicate that the estimates are sharp. The analysis is set in one dimension, but can be easily generalized to tensor product meshes in 2D. Received: December 21, 1998; revised March 17, 1999     

Pragmatic software tools for water reuse evaluation in a factory

The optimal use of process water becomes increasingly important since natural water resources are heavily solicited by a growing economy. Two steps can be considered in the process water optimization. A first step is the inventory of the different process streams in the process water network. Pure mathematical modeling of a dynamic water network is extremely complicated and expensive. As an approximation, the use of a steady-state network node model within commercial software is accepted to set up a water balance. Sophisticated software tools are available but common solver software may offer an alternative. A second step is the water “pinch” which searches for an optimal use of process water by combining sources and sinks, taking into account contaminant concentrations of process streams. Sophisticated pinch software can be applied but it is also possible to implement a simplified combinatory approach. Such approach can be pragmatically programmed in e.g., Visual Basic. Such tool allows for a first evaluation of the complex combinatory sources–sinks problem, enabling a low cost and easy-to-handle first interpretation of possible water-reuse opportunities. This could stimulate a further enhanced analysis with more advanced software tools and therefore promote a sustainable use of process water in the industrialized world.     

Design of a Research Performance Measurement System: The Case of NIAB

At NIAB, a UK based company that provides research, services and information to the agricultural and food sector, a system has been designed that helps to assess and manage the growing research programme of the company. Since the company was ‘privatised’ four years ago, research activities have increased and moved away from solely applied research to a mix of applied and more fundamental research. Being a key element of the new developed company strategy, research now plays an increasing important role in broadening the scope of the company and keeping current services competitive by driving innovation. All research at NIAB is externally funded. In this paper we report on the process to design NIAB’s performance measurement system, for which the Performance measurement system Systematic Design Approach was used. The design process was started with an elaborate structured problem analysis of the research process and its inter and extra–organisational context. Based upon this analysis, firstly a conceptual and secondly a detail design of a performance measurement system was made. To maximise the leverage from research, the system has been designed to optimise the value delivered to the funder as well as the value delivered to internal customers in the form of knowledge that drives innovation.