Bauer Method of MVDR Spectral Factorization for Pitch Modification in the Source Domain

In our earlier work [1], we employed MVDR (minimum variance distortionless response) based spectral estimation instead of modified-linear prediction method [2] in pitch modification. Here, we use the Bauer method of MVDR spectral factorization, leading to a causal inverse filter rather than a noncausal filter setup with MVDR spectral estimation [1]. Further, this is employed to obtain source (or residual) signal from pitch synchronous speech frames. The residual signal is resampled using DCT/IDCT depending on the target pitch scale factor. Finally, forward filters realized from the above factorization are used to get pitch modified speech. The modified speech is evaluated subjectively by 10 listeners and mean opinion scores (MOS) are tabulated. Further, modified bark spectral distortion measure is also computed for objective evaluation of performance. We find that the proposed algorithm performs better compared to time domain pitch synchronous overlap [3] and modified-LP method [2]. A good MOS score is achieved with the proposed algorithm compared to [1] with a causal inverse and forward filter setup.

Development of an efficiency equation for solar evaporator- collectors

Considering the growing energy needs and concern for environmental degradation, clean and inexhaustible energy sources, e.g solar energy are receiving greater attention for various applications. The use of solar energy systems for low temperature applications reduces the burden on conventional fossil fuels and has little or no harmful effects on the environment. The performance of a solar system depends to a great extent on the collector used for the conversion of solar radiant energy to thermal energy. A solar evaporatorcollector (SEC) is basically an unglazed flat plate collector where refrigerant, like R134a, is used as the working fluid. As the operating temperature of SEC is very low, it collects energy both from solar irradiation and ambient energy leading to a much higher efficiency than the conventional collectors. The capability of SEC to utilize ambient energy also enables the system to operate at night. Therefore it is not appropriate to use for the evaluation of performance of SEC by conventional efficiency equation where ambient energy and condensation is not considered as energy input in addition to irradiation. In the National University of Singapore, several Solar Assisted Heat Pump (SAHP) systems were built for the evaluation of performance under the metrological condition of Singapore for thermal applications of desalination and SEC was the main component to harness renewable energy. In this paper, the design and performance of SEC are explored. Furthermore, an attempt is made to develop an efficiency equation for SEC and maximum efficiency attained 98% under the meteorological condition of Singapore.

How can evaluative thinking and practice inform performance models for organizations and personnel

In the world today there are many ways in which we measure, count and determine whether something is worth the effort or not. In Australia and many other countries, new government legislation is requiring government-funded entities to become more transparent in their practice and to develop a more cohesive narrative about the worth, or impact, for the betterment of society. This places the executives of such entities in a position of needing evaluative thinking and practice to guide how they may build the narrative that documents and demonstrates this type of impact. In thinking about where to start, executives, project and program managers may consider this workshop as a professional development opportunity to explore both the intended and unintended consequences of performance models as tools of evaluation. This workshop will offer participants an opportunity to unpack the place of performance models as an evaluative tool through the following: · What shape does an ethical, sound and valid performance measure for an organization or personnel take? · What role does cultural specificity play in the design and development of a performance model for an organization or for personnel? · How are stakeholders able to identify risk during the design and development of such models? · When and where will dissemination strategies be required? · And so what? How can you determine that your performance model implementation has made a difference now or in the future?

Influence of surface texture and roughness parameters on friction and transfer layer formation during sliding of aluminium pin on steel plate

Surface texture of harder mating surfaces plays an important role during sliding against softer materials and hence the importance of characterizing the surfaces in terms of roughness parameters. In the present investigation, basic studies were conducted using inclined pin-on-plate sliding tester to understand the surface texture effect of hard surfaces on coefficient of friction and transfer layer formation. A tribological couple made of a super purity aluminium pin against steel plate was used in the tests. Two surface parameters of steel plates, namely roughness and texture, were varied in the tests. It was observed that the transfer layer formation and the coefficient of friction along with its two components, namely, the adhesion and plowing, are controlled by the surface texture and are independent of surface roughness (R-a). Among the various surface roughness parameters, the average or the mean slope of the profile was found to explain the variations best. Under lubricated conditions, stick-slip phenomena was observed, the amplitude of which depends on the plowing component of friction. The presence of stick-slip motion under lubricated conditions could be attributed to the molecular deformation of the lubricant component confined between asperities. (C) 2009 Elsevier B. V. All rights reserved.

The association between student characteristics and the development of clinical reasoning in a graduate-entry, PBL medical programme

This study sought to assess the extent to which the entry characteristics of students in a graduate-entry medical programme predict the subsequent development of clinical reasoning ability. Subjects comprised 290 students voluntarily recruited from three successive cohorts of the University of Queensland's MBBS Programme. Clinical reasoning was measured once a year over a period of three years using two methods, a set of 10 Clinical Reasoning Problems (CRPs) and the Diagnostic Thinking Inventory (DTI). Data on gender, age at entry into the programme, nature of primary degree, scores on selection criteria (written examination plus interview) and academic performance in the first two years of the programme were recorded for each student, and their association with clinical reasoning skill analysed using univariate and multivariate analysis. Univariate analysis indicated significant associations between CRP score, gender and primary degree with a significant but small association between DTI and interview score. Stage of progression through the programme was also an important predictor of performance on both indicators. Subsequent multivariate analysis suggested that female gender is a positive predictor of CRP score independently of the nature of a subject's primary degree and stage of progression through the programme, although these latter two variables are interdependent. Positive predictors of clinical reasoning skill are stage of progression through the MBBS programme, female gender and interview score. Although the nature of a student's primary degree is important in the early years of the programme, evidence suggests that by graduation differences between students' clinical reasoning skill due to this factor have been resolved.

Enhanced Tetrahedral Ordering of Water Molecules in Minor Grooves of DNA: Relative Role of DNA Rigidity, Nanoconfinement, and Surface Specific Interactions

Confinement and Surface specific interactions call induce Structures otherwise unstable at that temperature and pressure. Here we Study the groove specific water dynamics ill the nucleic acid sequences, poly-AT and poly-GC, in long B-DNA duplex chains by large scale atomistic molecular dynamics simulations, accompanied by thermodynamic analysis. While water dynamics in the major groove remains insensitive to the sequence differences, exactly the opposite is true for the minor groove water. Much slower water dynamics observed in the minor grooves (especially in the AT minor) call be attributed to all enhanced tetrahedral ordering (< t(h)>) of water. The largest value of < t(h)> in the AT minor groove is related to the spine of hydration found in X-ray Structure. The calculated configurational entropy (S-C) of the water molecules is found to be correlated with the self-diffusion coefficient of water in different region via Adam-Gibbs relation D = A exp(-B/TSC), and also with < t(h)>.

Optical Studies of the Antarctic Glacio-Oceanic System

The Antarctic system comprises of the continent itself, Antarctica, and the ocean surrounding it, the Southern Ocean. The system has an important part in the global climate due to its size, its high latitude location and the negative radiation balance of its large ice sheets. Antarctica has also been in focus for several decades due to increased ultraviolet (UV) levels caused by stratospheric ozone depletion, and the disintegration of its ice shelves. In this study, measurements were made during three Austral summers to study the optical properties of the Antarctic system and to produce radiation information for additional modeling studies. These are related to specific phenomena found in the system. During the summer of 1997-1998, measurements of beam absorption and beam attenuation coefficients, and downwelling and upwelling irradiance were made in the Southern Ocean along a S-N transect at 6°E. The attenuation of photosynthetically active radiation (PAR) was calculated and used together with hydrographic measurements to judge whether the phytoplankton in the investigated areas of the Southern Ocean are light limited. By using the Kirk formula the diffuse attenuation coefficient was linked to the absorption and scattering coefficients. The diffuse attenuation coefficients (Kpar) for PAR were found to vary between 0.03 and 0.09 1/m. Using the values for KPAR and the definition of the Sverdrup critical depth, the studied Southern Ocean plankton systems were found not to be light limited. Variabilities in the spectral and total albedo of snow were studied in the Queen Maud Land region of Antarctica during the summers of 1999-2000 and 2000-2001. The measurement areas were the vicinity of the South African Antarctic research station SANAE 4, and a traverse near the Finnish Antarctic research station Aboa. The midday mean total albedos for snow were between 0.83, for clear skies, and 0.86, for overcast skies, at Aboa and between 0.81 and 0.83 for SANAE 4. The mean spectral albedo levels at Aboa and SANAE 4 were very close to each other. The variations in the spectral albedos were due more to differences in ambient conditions than variations in snow properties. A Monte-Carlo model was developed to study the spectral albedo and to develop a novel nondestructive method to measure the diffuse attenuation coefficient of snow. The method was based on the decay of upwelling radiation moving horizontally away from a source of downwelling light. This was assumed to have a relation to the diffuse attenuation coefficient. In the model, the attenuation coefficient obtained from the upwelling irradiance was higher than that obtained using vertical profiles of downwelling irradiance. The model results were compared to field measurements made on dry snow in Finnish Lapland and they correlated reasonably well. Low-elevation (below 1000 m) blue-ice areas may experience substantial melt-freeze cycles due to absorbed solar radiation and the small heat conductivity in the ice. A two-dimensional (x-z) model has been developed to simulate the formation and water circulation in the subsurface ponds. The model results show that for a physically reasonable parameter set the formation of liquid water within the ice can be reproduced. The results however are sensitive to the chosen parameter values, and their exact values are not well known. Vertical convection and a weak overturning circulation is generated stratifying the fluid and transporting warmer water downward, thereby causing additional melting at the base of the pond. In a 50-year integration, a global warming scenario mimicked by a decadal scale increase of 3 degrees per 100 years in air temperature, leads to a general increase in subsurface water volume. The ice did not disintegrate due to the air temperature increase after the 50 year integration.

Activity of Ferric Oxide in Steelmaking Slag

Refining reactions in steelmaking primarily involve oxidation of impurity element(s). The oxidation potential of the slag and the activity of oxygen in the metal (h(O)) are the major factors controlling these chemical reactions. In turn, the oxidation potential of the slag is influenced strongly by the equilibrium distribution of oxygen between ferrous and ferric oxides. We recently investigated the activity coefficient of FeO in steelmaking slag and the effect of chemical composition thereon. This work is focused on estimation of theactivity coefficient of Fe2O3.

Modelling Cued-Target Recall using Quantum Inspired Models of Target Activation

This article presents and evaluates Quantum Inspired models of Target Activation using Cued-Target Recall Memory Modelling over multiple sources of Free Association data. Two components were evaluated: Whether Quantum Inspired models of Target Activation would provide a better framework than their classical psychological counterparts and how robust these models are across the different sources of Free Association data. In previous work, a formal model of cued-target recall did not exist and as such Target Activation was unable to be assessed directly. Further to that, the data source used was suspected of suffering from temporal and geographical bias. As a consequence, Target Activation was measured against cued-target recall data as an approximation of performance. Since then, a formal model of cued-target recall (PIER3) has been developed [10] with alternative sources of data also becoming available. This allowed us to directly model target activation in cued-target recall with human cued-target recall pairs and use multiply sources of Free Association Data. Featural Characteristics known to be important to Target Activation were measured for each of the data sources to identify any major differences that may explain variations in performance for each of the models. Each of the activation models were used in the PIER3 memory model for each of the data sources and was benchmarked against cued-target recall pairs provided by the University of South Florida (USF). Two methods where used to evaluate performance. The first involved measuring the divergence between the sets of results using the Kullback Leibler (KL) divergence with the second utilizing a previous statistical analysis of the errors [9]. Of the three sources of data, two were sourced from human subjects being the USF Free Association Norms and the University of Leuven (UL) Free Association Networks. The third was sourced from a new method put forward by Galea and Bruza, 2015 in which pseudo Free Association Networks (Corpus Based Association Networks - CANs) are built using co-occurrence statistics on large text corpus. It was found that the Quantum Inspired Models of Target Activation not only outperformed the classical psychological model but was more robust across a variety of data sources.

Influence of tilt angle of plate on friction and transfer layer—A study of aluminium pin sliding against steel plate

In the present investigation, unidirectional grinding marks were attained on the steel plates. Then aluminium (Al) pins were slid at 0.2°, 0.6°, 1.0°, 1.4°, 1.8°, 2.2° and 2.6° tilt angles of the plate with the grinding marks perpendicular and parallel to the sliding direction under both dry and lubricated conditions using a pin-on-plate inclined sliding tester to understand the influence of tilt angle and grinding marks direction of the plate on coefficient of friction and transfer layer formation. It was observed that the transfer layer formation and the coefficient of friction depend primarily on the grinding marks direction of the harder mating surface. Stick-slip phenomenon was observed only under lubricated conditions. For the case of pins slid perpendicular to the unidirectional grinding marks stick-slip phenomenon was observed for tilt angles exceeding 0.6°, the amplitude of which increases with increasing tilt angles. However, for the case of the pins slid parallel to the unidirectional grinding marks the stick-slip phenomena was observed for angles exceeding 2.2°, the amplitude of which also increases with increasing tilt angle. The presence of stick-slip phenomena under lubricated conditions could be attributed to the molecular deformation of the lubricant component confined between asperities.

Tribology of steel/steel interaction in oil-in-water mulsion; a rationale for lubricity

Oil droplets are dispersed in water by an anionic urfactant to form an emulsion. The lubricity of this emulsion in steel/steel interaction is explored in a ball on flat nanotribometer. The droplet size and charge are measured using dynamic light scattering, while the substrate charge density is estimated using the pH titration method. These data are combined to calculate the DLVO forces for the droplets generated for a range of surfactant concentration and two oil to water volume ratios. The droplets have a clear bi-modal size distribution. The study shows that the smaller droplets which experience weak repulsion are situated (at the highest DLVO barrier) much closer to the substrate than thebigger droplets, which experience the same DLVO force, are. We suggest that the smaller droplets thus play a more important role in lubricity than what the bigger droplets do. The largest volume of such small droplets occurs in the 0.5 mM-1 mM range of surfactant concentration and 1% oil to water volume ratio, where the coefficient of friction is also observed to be the least. (C) 2010 Elsevier Inc. All rights reserved.

Methodological perspectives for register-based health system performance assessment : Developing a hip fracture monitoring system in Finland

The resources of health systems are limited. There is a need for information concerning the performance of the health system for the purposes of decision-making. This study is about utilization of administrative registers in the context of health system performance evaluation. In order to address this issue, a multidisciplinary methodological framework for register-based data analysis is defined. Because the fixed structure of register-based data indirectly determines constraints on the theoretical constructs, it is essential to elaborate the whole analytic process with respect to the data. The fundamental methodological concepts and theories are synthesized into a data sensitive approach which helps to understand and overcome the problems that are likely to be encountered during a register-based data analyzing process. A pragmatically useful health system performance monitoring should produce valid information about the volume of the problems, about the use of services and about the effectiveness of provided services. A conceptual model for hip fracture performance assessment is constructed and the validity of Finnish registers as a data source for the purposes of performance assessment of hip fracture treatment is confirmed. Solutions to several pragmatic problems related to the development of a register-based hip fracture incidence surveillance system are proposed. The monitoring of effectiveness of treatment is shown to be possible in terms of care episodes. Finally, an example on the justification of a more detailed performance indicator to be used in the profiling of providers is given. In conclusion, it is possible to produce useful and valid information on health system performance by using Finnish register-based data. However, that seems to be far more complicated than is typically assumed. The perspectives given in this study introduce a necessary basis for further work and help in the routine implementation of a hip fracture monitoring system in Finland.

On the design of quadratic weirs

This paper considers the problem of the design of the quadratic weir notch, which finds application in the proportionate method of flow measurement in a by-pass, such that the discharge through it is proportional to the square root of the head measured above a certain datum. The weir notch consists of a bottom in the form of a rectangular weir of width 2W and depth a over which a designed curve is fitted. A theorem concerning the flow through compound weirs called the “slope discharge continuity theorem” is discussed and proved. Using this, the problem is reduced to the determination of an exact solution to Volterra's integral equation in Abel's form. It is shown that in the case of a quadratic weir notch, the discharge is proportional to the square root of the head measured above a datum Image a above the crest of the weir. Further, it is observed that the function defining the shape of the weir is rapidly convergent and its value almost approximates to zero at distances of 3a and above from the crest of the weir. This interesting and significant behaviour of the function incidentally provides a very good approximate solution to a particular Fredholm integral equation of the first kind, transforming the notch into a device called a “proportional-orifice”. A new concept of a “notch-orifice” capable of passing a discharge proportional to the square root of the head (above a particular datum) while acting both as a notch, and as an orifice, is given. A typical experiment with one such notch-orifice, having A = 4 in., and W = 6 in., shows a remarkable agreement with the theory and is found to have a constant coefficient of discharge of 0.61 in the ranges of both notch and orifice.

Thermal expansion of caesium bromide

The temperature variation of the coefficient of thermal expansion of caesium bromide has been computed in quasiharmonic approximation and compared with the experimental results.

The significance of brittle reaction layers in fusing of dental ceramics to titanium

This thesis comprises four intercomplementary parts that introduce new approaches to brittle reaction layers and mechanical compatibility of metalloceramic joints created when fusing dental ceramics to titanium. Several different methods including atomic layer deposition (ALD), sessile drop contact angle measurements, scanning acoustic microscopy (SAM), three-point bending (TPB, DIN 13 927 / ISO 9693), cross-section microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) were employed. The first part investigates the effects of TiO2 layer structure and thickness on the joint strength of the titanium-metalloceramic system. Samples with all tested TiO2 thicknesses displayed good ceramics adhesion to Ti, and uniform TPB results. The fracture mode was independent of oxide layer thickness and structure. Cracking occurred deeper inside titanium, in the oxygen-rich Ti[O]x solid solution surface layer. During dental ceramics firing TiO2 layers dissociate and joints become brittle with increased dissolution of oxygen into metallic Ti and consequent reduction in the metal plasticity. To accomplish an ideal metalloceramic joint this needs to be resolved. The second part introduces photoinduced superhydrophilicity of TiO2. Test samples with ALD deposited anatase TiO2 films were produced. Samples were irradiated with UV light to induce superhydrophilicity of the surfaces through a cascade leading to increased amount of surface hydroxyl groups. Superhydrophilicity (contact angle ~0˚) was achieved within 2 minutes of UV radiation. Partial recovery of the contact angle was observed during the first 10 minutes after UV exposure. Total recovery was not observed within 24h storage. Photoinduced ultrahydrophilicity can be used to enhance wettability of titanium surfaces, an important factor in dental ceramics veneering processes. The third part addresses interlayers designed to restrain oxygen dissolution into Ti during dental ceramics fusing. The main requirements for an ideal interlayer material are proposed. Based on these criteria and systematic exclusion of possible interlayer materials silver (Ag) interlayers were chosen. TPB results were significantly better in when 5 μm Ag interlayers were used compared to only Al2O3-blasted samples. In samples with these Ag interlayers multiple cracks occurred inside dental ceramics, none inside Ti structure. Ag interlayers of 5 μm on Al2O3-blasted samples can be efficiently used to retard formation of the brittle oxygen-rich Ti[O]x layer, thus enhancing metalloceramic joint integrity. The most brittle component in metalloceramic joints with 5 μm Ag interlayers was bulk dental ceramics instead of Ti[O]x. The fourth part investigates the importance of mechanical interlocking. According to the results, the significance of mechanical interlocking achieved by conventional surface treatments can be questioned as long as the formation of the brittle layers (mainly oxygen-rich Ti[O]x) cannot be sufficiently controlled. In summary in contrast to former impressions of thick titanium oxide layers this thesis clearly demonstrates diffusion of oxygen from sintering atmosphere and SiO2 to Ti structures during dental ceramics firing and the following formation of brittle Ti[O]x solid solution as the most important factors predisposing joints between Ti and SiO2-based dental ceramics to low strength. This among other predisposing factors such as residual stresses created by the coefficient of thermal expansion mismatch between dental ceramics and Ti frameworks can be avoided with Ag interlayers.