Differential surface models for tactile perception of shape and on-line tracking of features

Tactile perception of shape involves an on-line controller and a shape perceptor. The purpose of the on-line controller is to maintain gliding or rolling contact with the surface, and collect information, or track specific features of the surface such as edges of a certain sharpness. The shape perceptor uses the information to perceive, estimate the parameters of, or recognize the shape. The differential surface model depends on the information collected and on the a priori information known about the robot and its physical parameters. These differential models are certain functionals that are projections of the dynamics of the robot onto the surface gradient or onto the tangent plane. A number of differential properties may be directly measured from present day tactile sensors. Others may have to be indirectly computed from measurements. Others may constitute design objectives for distributed tactile sensors of the future. A parameterization of the surface leads to linear and nonlinear sequential parameter estimation techniques for identification of the surface. Many interesting compromises between measurement and computation are possible

Collocation Method using Compactly Supported Radial Basis Function for Solving Volterra's Population Model

In this paper, indirect collocation approach based on compactly supported radial basis function is applied for solving Volterras population model. The method reduces the solution of this problem to the solution of a system of algebraic equations. Volterras model is a non-linear integro-differential equation where the integral term represents the effect of toxin. To solve the problem, we use the well-known CSRBF: Wendland3,5. Numerical results and residual norm 2 show good accuracy and rate of convergence.Comment: 8 pages , 1 figure. arXiv admin note: text overlap with arXiv:1008.233

Renal function assessment in adults with recurrent calcium kidney stone disease

The prevalence of nephrolihiasis and chronic kidney disease has risen over the past three decades, we sought to determine if person with a history of kidney stones have lower renal function relative to non stone formers. Methods: We conducted a case-control study utilizing 138 recurrent calcium kidney stone formers and 127 age and gender matched controls with no history of renal disease, all subjects were aged 30-55 years old, with no history of hypertension, diabetes mellitus, congestive heart failure and liver disease and also no urinary tract obstruction and medications can affect Glomerular Filtration Rate (GFR). We estimated GFR by Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EP I) equations and categorized using cut points suggested by Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines. Results: Mean GFR in case group and control group was: 80.17(18.45) ml/min/1.73m2 and 83.80(15.75) ml/ min/1.73m2 respectively (P value: 0.09). Distribution of subjects among stone formers in stage I, II, III was 59(42.8%), 71(51.4%) and 8(5.8%) and in control group was 67(52.8%), 59(46.4%) and 1(0.8%) respectively, (p: 0.03). There was an inverse correlation between GFR and number of passed stone but there was no significant correlation between history of extracorporeal shock wave lithotripsy (ESWL) or percutaneous nephrolithotomy (PCNL) and estimated GFR. Conclusion: Recurrent calcium stone disease may be associated with nephron damage and an increased risk of chronic kidney disease

Numerical investigation of Differential Biological-Models via GA-Kansa Method Inclusive Genetic Strategy

In this paper, we use Kansa method for solving the system of differential equations in the area of biology. One of the challenges in Kansa method is picking out an optimum value for Shape parameter in Radial Basis Function to achieve the best result of the method because there are not any available analytical approaches for obtaining optimum Shape parameter. For this reason, we design a genetic algorithm to detect a close optimum Shape parameter. The experimental results show that this strategy is efficient in the systems of differential models in biology such as HIV and Influenza. Furthermore, we prove that using Pseudo-Combination formula for crossover in genetic strategy leads to convergence in the nearly best selection of Shape parameter.Comment: 42 figures, 23 page

Is a low sacral ratio associated with primary vesicoureteral reflux in children?

Introduction: The association of sacral anomalies with fecal incontinence and lower urinary tract dysfunction is known. The sacral ratio is proposed as a tool for evaluation of sacral development. The aim of this cross-sectional study was to evaluate the prevalence and severity of vesicoureteral reflux in children with a low sacral ratio. Materials and Methods: Six hundred and sixty nine children who were referred to a radiology clinic for a standard (fluoroscopic) VCUG to detect vesicoureteral reflux and other anomalies of the lower urinary tract after an episode of urinary tract infection were included in the study and their sacral ratios were measured. Results: All children were younger than 14 years of age (mean 3.44±3.20). Of 669 children, 593 (88.6%) had normal sacral ratios out of whom 423 (71.3%) did not have VUR and 170 (28.7%) had VUR. Seventy-six (11.3%) children out of 669 cases had low sacral ratios; 49 (64.5%) of them had no VUR and 27 (35.5%) had VUR. There was no significant difference in the prevalence of VUR between children with and without a low sacral ratio (p value=0.217). Also, there was no significant difference or trend between a low sacral ratio and the severity of reflux (Chi2 for trend). Conclusions: Although sacral anomalies may be related to some cases of VUR by producing lower urinary tract dysfunction, the sacral ratio is not associated with VUR

Multiple Description Quantization via Gram-Schmidt Orthogonalization

The multiple description (MD) problem has received considerable attention as a model of information transmission over unreliable channels. A general framework for designing efficient multiple description quantization schemes is proposed in this paper. We provide a systematic treatment of the El Gamal-Cover (EGC) achievable MD rate-distortion region, and show that any point in the EGC region can be achieved via a successive quantization scheme along with quantization splitting. For the quadratic Gaussian case, the proposed scheme has an intrinsic connection with the Gram-Schmidt orthogonalization, which implies that the whole Gaussian MD rate-distortion region is achievable with a sequential dithered lattice-based quantization scheme as the dimension of the (optimal) lattice quantizers becomes large. Moreover, this scheme is shown to be universal for all i.i.d. smooth sources with performance no worse than that for an i.i.d. Gaussian source with the same variance and asymptotically optimal at high resolution. A class of low-complexity MD scalar quantizers in the proposed general framework also is constructed and is illustrated geometrically; the performance is analyzed in the high resolution regime, which exhibits a noticeable improvement over the existing MD scalar quantization schemes.Comment: 48 pages; submitted to IEEE Transactions on Information Theor

Development of a Transient System Model of Mobile Air-Conditioning Systems

A transient model was developed to predict the behavior of the vapor compression cycle of a mobile air-conditioning system. Mobile air-conditioning systems operate in a transient mode due to variations in compressor speed, variations in condenser air flow rate, and the controls strategy such as clutch-cycling. We developed a model to simulate start-up transients, clutch cycling transients, city-driving transients, and shut-down transients including the following charge redistribution. Our transient model treats the components in a vapor compression refrigeration system including the compressor, condenser, orifice tube, evaporator, and accumulator. The heat exchangers are divided into a series of constant-volume cells. The conservation of mass, conservation of energy, and conservation of momentum equations are applied to each cell. The number of cells and/or the volume of the cells can be changed between simulations in order to change the resolution of the model. The accumulator model is a modification of the heat exchanger model which constrains the outlet to always be vapor. The orifice tube model and the compressor model are semi-empirical. The model is validated with steady-state and transient data obtained from a test facility specifically designed to simulate mobile air-conditioners. The steady-state model predicts most of the system parameters to within ??15%. The transient model predicted the behavior of the city driving cycle, compressor shut-down, compressor start-up, and clutch-cycling simulations well. An important part of the system model is calculating the refrigerant properties correctly. We developed refrigerant property routines to the calculate equilibrium thermodynamic properties in the liquid, vapor, two-phase liquid-vapor, and supercritical region using the Modified-Benedict-Webb-Rubin equation of state. Our property routines accurately solve for a given output property for applicable combinations of input properties. They also accurately predict whether the refrigerant is in the single-phase or two-phase region. The property routines agree extremely well with the experimental data found in the literature.Air Conditioning and Refrigeration Project 7