Design of fiducials for accurate registration using machine vision

The effect of the shape and size of a standard feature (fiducial) on the positional accuracy of the centroid in machine-vision applications is studied. It is shown that a circular fiducial provides superior subpixel registration accuracy among the fiducial shapes typically used today     

A spiking half-cognitive model for classification

This paper describes a spiking neural network that learns classes. Following a classic Psychological task, the model learns some types of classes better than other types, so the net is a spiking cognitive model of classification. A simulated neural system, derived from an existing model, learns natural kinds, but is unable to form sufficient attractor states for all of the types of classes. An extension of the model, using a combination of singleton and triplets of input features, learns all of the types. The models make use of a principled mechanism for spontaneous firing, and a compensatory Hebbian learning rule. Combined, the mechanisms allow learning to spread to neurons not directly stimulated by the environment. The overall network learns the types of classes in a fashion broadly consistent with the Psychological data. However, the order of speed of learning the types is not entirely consistent with the Psychological data, but may be consistent with one of two Psychological systems a given person possesses. A Psychological test of this hypothesis is proposed.     

BER of Differentially Detected π/4-DQPSK with Selection Combining in Nakagami-m Fading

Nakagami’s m distribution is a versatile statistical model to characterize small-scale multipath fading in wireless channels. On the other hand, selection combining (SC) is a widely practiced diversity technique to mitigate the detrimental effects of multipath fading. Thus, when SC is applied over Nakagami fading channel, the error performance improvement for any given modulation format is of considerable interest. Since the last decade, π/4-shifted differential quadrature phase shift keying (π/4-DQPSK) modulation has attracted much attention as it is used for high-capacity code division multiple access (CDMA) based digital cellular systems. One of the major reasons behind this is the provision for differential detection which allows production of low complexity mobile units. In this paper, we present analytical expressions for bit error rate (BER) of π/4-DQPSK modulation with L-branch SC diversity in Nakagami-m fading channels perturbed by additive white Gaussian noise (AWGN). The derived end expressions are in closed form and contain finite series of Gaussian hypergeometric function. This makes evaluation of error rates much more straightforward compared to earlier approaches that required single or even double numerical integration. Some special instances such as the nondiversity case and Rayleigh fading case are also investigated and plotted along with the main findings. For different fading parameter (m) values and for different diversity orders (L), simulated results are shown to be in excellent agreement with the derived analytical results. All the results are, however, limited to integer values of fading severity parameter m.     

Multi-User Relaying of High-Rate Space–Time Code in Cooperative Networks

In this paper, we propose high-rate space–time coding for cooperative wireless networks to reduce the overall delay incurred in relaying signals to multiple receivers. The relay structure is optimized in order to achieve maximum SNR at the receiver nodes. The proposed scheme provides a significant reduction in the delay required for the relaying and transmission of the signals to the multiple receivers with a minute loss in performance. We have also shown by simulation that this loss in the performance could be recovered by selecting more number of relays. We propose two relaying strategies for high-rate space–time codes, which are very useful in providing high data-rate in wireless cooperative networks.     

Sputter deposition of self-organized nanoclusters through porous anodic alumina templates

Silver nanoparticles were sputter deposited through self organized hexagonally ordered porous anodic alumina templates that were fabricated using a two-step anodization process. The average pore diameter of the template was 90 nm and the interpore spacing was 120 nm. Atomic force microscope studies of the sputter-deposited silver nanoparticle array on a Si substrate indicate an approximate replication of the porous anodic alumina mask. The nature of the deposition depends strongly on the process parameters such as sputtering voltage, ambient pressure and substrate temperature. We report a detailed study of the sputtering conditions that lead to an optimal deposition through the template.     

Joint fatigue-based optimal posture prediction for maximizing endurance time in box carrying task

Multibody System Dynamics - In this study, the three-compartment controller fatigue model is integrated with an inverse dynamics optimization routine to predict the optimal posture, joint fatigue,...     

Mechanical and surface properties of corona-treated titanium dioxide-embedded opaque white low-density/Linear low-density polyethylene film

This study encompasses the characterization of corona-treated milky white co-extruded polyethylene films. The surface energies developed at various applied voltages were investigated by standard wetting (dyne) solutions of binary liquid mixtures. A maximum treatment of 40 dynes/cm was achieved at 3.0 kW of the applied load. Maximum heat seal joint strength of 1.05 kN/m was achieved only when an untreated/untreated surface combination was sealed, while a treated/treated surface combination exhibited the minimum heat seal joint strength of 0.98 kN/m. Standard Scotch tape method was employed for testing peel adhesion. An applied load of more than 3.0 kW shows a decreasing trend in surface energy. The coefficient of friction on the treated surface was also investigated. Aging under different environmental conditions had hardly any impact on the treatment levels within the time period under study. A sufficiently opaque (Opacity—99%) white film at Titanium dioxide (TiO₂) loading of 7.5% resulted in a very good barrier film.     

Expert system, fuzzy logic, and neural network applications inpower electronics and motion control

Artificial intelligence (AI) tools, such as expert systems, fuzzy logic, and neural networks are expected to usher a new era in power electronics and motion control in the coming decades. Although these technologies have advanced significantly and have found wide applications, they have hardly touched the power electronics and machine drives area. The paper describes these AI tools and their application in the area of power electronics and motion control. The body of the paper is subdivided into three sections which describe, respectively, the principles and applications of expert systems, fuzzy logic, and neural networks. The theoretical portion of each topic is of direct relevance to the application of power electronics. The example applications in the paper are taken from the published literature