Estimating the scattering distribution of the received signals in multipath fading channels

This paper presents a novel approach for estimating the distribution of the incoming waves at the mobile unit antenna, i.e. the scattering distribution, in a typical micro-cellular system. This estimate is vital in determining many system parameters of interest as well as designing unbiased estimators for the velocity of mobile units in micro-cellular systems. The proposed approach deploys the zero-crossing rates of the quadrature components and the instantaneous frequency of the received signal at the mobile unit to estimate the scattering distribution. We also propose a new model for simulating multipath fading channels with non-isotropic scattering. We use the channel simulator to evaluate the performance of the proposed estimator for the scattering distribution. Simulation results show that proposed estimator exhibits small bias and root mean square error.     

Effect of pH,Temperature and Reaction Time on Calcium Binding by Hydroxypropyl Rice Starches

Calcium binding by both native and hydroxypropyl starches was studied in aqueous media under different pH, temperature and reaction times at various calcium: starch ratios. Calcium binding was markedly influenced by pHs and temperatures of the reaction mixture. Reaction times did not show marked influence on calcium binding. Maximum calcium binding was observed in alkaline pH and at lower temperature. Most of the calcium bound within the first 20 minutes. Thus, alkaline pH and lower temperature is more favourable for calcium binding by both native and hydroxypropyl rice starches compared to acidic pH and higher temperatures.     

Distribution of Partial Digestion Products of Hydroxypropyl Derivatives of Maize (NM), Waxy Maize (WM) and High Amylose (HA) Maize Starches

Porcine pancreatic α-amylase digests of native and hydroxypropyl derivatives of maize, waxy maize and high amylose maize starches were subjected to ethanolic fractionation into oligosaccharide and polysaccharide fractions. Both fractions of the partial digests were analysed for blue values, reducing values, total carbohydrate, average degree of polymerisation and molar substitution (MS). Distribution of hydroxypropyl groups between the fractions varied depending on starch type and level of substitution with the polysaccharide fraction being higher in MS. Blue values (BV) and average degree of polymerisation (DP) tended to decrease with digestion while reducing (RV) increased.     

On mechanical properties of sago starch/poly(ε‐caprolactone) composites

Four types of sago starch were incorporated into a poly(ε‐caprolactone) (PCL) matrix, native, predried, thermoplastic starch (TPS) granules and TPS. All systems were found to be phase‐separated. Tensile properties were obtained after formulation of various mixtures and processing of suitable test specimens. It was found that elongation at break of composites comprising native starch and thermoplastic starch decreases almost linearly with volume fraction of starch whereas tendencies to nonlinear dependencies were observed for predried and thermoplastic starch granules. Except for composites containing native starch, tensile strength was found to decrease linearly with volume fraction of starch. However, statistical analysis of the corresponding regression coefficients shows that the coefficients ruling the compostion dependence of tensile properties are not significantly different for the four starch types. One may conclude that in all cases, tensile properties decrease almost linearly with volume fraction and maximum volume fraction of starch loading is around 0.6. Scanning electron micrographs of fracture surfaces revealed weak interfacial adhesion between sago starch and the polymer matrix.     

Classification of normal/abnormal PCG recordings using a time–frequency approach

The early and accurate diagnosis of cardiovascular diseases (CVDs) are of great importance as they allow early and proper medical treatment and therefore result in reducing the chance of the CVDs being developed to an acute level. In medical procedures, the first step in examining the cardiovascular function is the auscultation of the heart. However, the correct medical diagnosis based on the heart sounds through a stethoscope requires a lot of expertise and, in some cases, needs referral of the patient to a cardiologist. This is not only time-consuming but also imposes a financial burden on the medical system. Thus, automated detection and analysis of the recorded heart sound auscultation has received a lot of attentions in recent years. This study presents a new time–frequency (T–F) based approach for classifying phonocardiogram (PCG) signals into normal and abnormal. In the proposed methodology, each PCG recording is first segmented into the 4 fundamental heart cycles, i.e. S1, systole, S2, and diastole. From each state, a set of T–F features are extracted with the aim of identifying their characteristics in the T–F domain. The features are then applied to a support vector machine to classify the PCG signal into normal or abnormal. The performance of the proposed method is evaluated using the 2016 PhysioNet challenge database and compared with that of the best performing existing methods. The experimental results using tenfold cross-validation show that the proposed method outperforms the existing methods in terms of sensitivity, specificity, and accuracy.

     

Thermal Behaviour of Calcium-Hydroxypropyl Rice Starch Complexes

Thermal behaviour of hydroxypropyl rice starches and their calcium complexes was determined by using Differential Scanning Calorimetry (DSC) with starch: water in the ratio of 1:1. Glass transition and gelatinization temperatures were reduced by hydroxypropyl groups and enhanced by calcium treatment. Gelatinization enthalpies were reduced by both hydroxypropyl groups and calcium treatment. The interaction of hydroxypropyl groups and calcium with starch altered the two endothermic peaks observed in native starch into a single melting peak.     

Distribution of Partial Digestion Products of Hydroxypropyl Derivatives of Maize,Waxy Maize and High Amylose Maize Starches

Porcine pancreatic α-amylase digests of native and hydroxypropyl derivatives of maize (NM), waxy maize (WM) and high amylose maize starches (HA) were subjected to ethanolic fractionation into oligosaccharide and polysaccharide fractions. Both fractions of the partial digests were analysed for blue values, reducing values, total carbohydrates, average degree of polymerisation and molar substitution (MS). Distribution of hydroxypropyl groups between the fractions varied depending on starch type and level of substitution with the polysaccharide fraction being higher in MS. Blue values (BV) and average degree of polymerisation (DP) tended to decrease with digestion while reducing values (RV) increased.     

Effect of calcium and hydroxypropylation on crystallinity and digestibility of rice starches

The digestibility of native and hydroxypropyl rice starches in the presence of calcium was investigated. Calcium interacted with native and hydroxypropyl rice starches and altered their relative crystallinity. Hydroxypropylation was measured in terms of molar substitution (MS) which in turn enhanced calcium binding. Depending upon the amount of calcium added (50–250 μg calcium per g dry starch) and levels of MS (ranging from 0·02 to 0·12), 25·4– 34·1 μg calcium was bound per g of hydroxypropyl starch. Native starch bound 25·4 μg calcium per g dry starch, which was much less than the hydroxy-propylated starches. Crystallinity decreased with the increase of MS and calcium concentration. Digestibility of ungelatinised hydroxypropyl starches increased with MS (2·5–4·1 mg reducing sugar released per g dry starch) and the trend is reversed in the gelatinised form. Calcium-induced amylolysis of the starches by porcine pancreatic α-amylase but somehow inhibited amyloglucosidase attack. © 1998 SCI.     

Sliding mode observers for nonlinear models with unbounded noise and measurement uncertainties

This work extends the applicability of variable structure observers designed for nonlinear systems in two ways. First, it is proved that these observers using a boundary-layer scheme can be applied to system models described by Ito differential equations, resulting in almost sure and mean square exponential estimation error. Second, the use of variable structure observers is extended to nonlinear measurement models containing disturbance effects. Also, a novel approach for obtaining the required parameters in the observer design is provided. Finally, two examples are given to illustrate the application and favorable convergence properties of these generalizations.     

Effect of Molar Substitution (MS) on Calcium Binding by Hydroxypropyl Rice Starches

Unisolated rice starch was obtained by wet milling of broken milled rice grains. Hydroxypropyl rice starches of different level of molar substitution (MS) were prepared and characterized. Both native and modified starches were treated with calcium carbonate at various calcium: starch ratios. Binding was markedly influenced by the calcium concentration in the reaction mixtures. Native starch binds less calcium than modified starch. Ability to bind calcium decreased with increasing calcium concentration in both native and modified starches. A parallel increased in calcium binding was observed as MS increased to the value of 0.09 and thereafter reversed. Increased level of substitution depressed the optical rotation and electrical conductivity of starch-calcium complex.