Multichannel fusion models for the parametric classification of differential brain activity

This paper introduces parametric multichannel fusion models to exploit the different but complementary brain activity information recorded from multiple channels in order to accurately classify differential brain activity into their respective categories. A parametric weighted decision fusion model and two parametric weighted data fusion models are introduced for the classification of averaged multichannel evoked potentials (EPs). The decision fusion model combines the independent decisions of each channel classifier into a decision fusion vector and a parametric classifier is designed to determine the EP class from the discrete decision fusion vector. The data fusion models include the weighted EP-sum model in which the fusion vector is a linear combination of the multichannel EPs and the EP-concatenation model in which the fusion vector is a vector-concatenation of the multichannel EPs. The discrete Karhunen-Loeve transform (DKLT) is used to select features for each channel classifier and from each data fusion vector. The difficulty in estimating the probability density function (PDF) parameters from a small number of averaged EPs is identified and the class conditional PDFs of the feature vectors of averaged EPs are, therefore, derived in terms of the PDFs of the single-trial EPs. Multivariate parametric classifiers are developed for each fusion strategy and the performances of the different strategies are compared by classifying 14-channel EPs collected from five subjects involved in making explicit match/mismatch comparisons between sequentially presented stimuli. It is shown that the performance improves by incorporating weights in the fusion rules and that the best performance is obtained using multichannel EP concatenation. It is also noted that the fusion strategies introduced are also applicable to other problems involving the classification of multicategory multivariate signals generated from multiple sources.     

Flexure of orthotropic rotating disks

The influence of off-set in mounting the blades on the disk, termed “eccentricity”, and the centrifugal stiffening on the stresses and deflection induced in laterally loaded orthotropic disks of variable thickness is analysed. The analysis is based on a series solution for the differential equation governing the deflection of the disk. Numerical results showing the effects of anisotropy, eccentricity and rotation on the stresses and deflection of the disk are presented graphically. It is shown that the stress due to radial bending moment reduces significantly with the increase in the degree of anisotropy.     

Early switch from intravenous to oral cephalosporins in the treatment of hospitalized patients with community-acquired pneumonia

BACKGROUND: Switch therapy is defined as the early transition from intravenous to oral antibiotics during treatment of infection. This study was designed to evaluate the clinical outcome and length of stay of hospitalized patients with community-acquired pneumonia treated with an early switch from intravenous to oral third-generation cephalosporins. METHODS: Patients with a new roentgenographic pulmonary infiltrate and at least two symptoms (cough, fever, or leukocytosis) were enrolled in this study and treated with intravenous ceftizoxime sodium (1 g every 12 hours) or ceftriaxone sodium (1 g every 24 hours). Patients were switched to oral cefixime (400 mg every 24 hours) as soon as they met the following criteria: (1) resolution of fever; (2) improvement of cough and respiratory distress; (3) improvement of leukocytosis; and (4) presence of normal gastrointestinal tract absorption. RESULTS: Of the 120 patients enrolled, 75 (62%) had clinical data evaluated. Long-term follow-up showed that 74 patients (99%) were cured; one patient required readmission for further intravenous therapy. Mean duration of hospital stay was 4 days. CONCLUSIONS: This investigation demonstrated that an early switch to oral cefixime may be reasonable in hospitalized patients with community-acquired pneumonia who have already shown a good clinical and laboratory response to therapy with intravenous third-generation cephalosporins. This approach is clinically effective and minimizes hospital stay.     

Design of optimal quantizers with an entropy constraint

Source encoding of transform domain coefficients can be used to obtain pictures of very good quality at low bit rates. Such a scheme requires that the entropy of the quantizer output be fixed at a prespecified value. The design of optimal quantizers subject to an entropy constraint is discussed in this paper and their specifications for three different input distributions associated with the transform coefficients is given.     

On an analytical-numerical procedure for the analysis of cylindrical shells with arbitrarily oriented cracks

An analytical-numerical procedure for obtaining stress intensity factor solutions for an arbitrarily oriented crack in a long, thin circular cylindrical shell is presented. The method of analysis involves obtaining a series solution to the governing shell equation in terms of Mathieu and modified Mathieu functions by the method of separation of variables and satisfying the crack surface boundary conditions numerically using collocation. The solution is then transformed from elliptic coordinates to polar coordinates with crack tip as the origin through a Taylor series expansion and membrane and bending stress intensity factors are computed. Numerical results are presented and discussed for the pressure loading case.     

A convex programming solution for gate-sizing with pipelining constraints

Optimization and Engineering - This paper proposes a novel geometric programming based formulation to solve a gate-sizing and retiming problem in the context of circuit optimization. The...     

On characterization of Microwave and Conventional Cast Bulk Brass

Corrosive resistant nature of brass makes it suitable for wide applications. Processing of bulk metallic materials using microwaves is still immature. Brass is taken in bulk form and melted using a 900 W domestic microwave applicator operating at 2.45 GHz frequency and modified with a controller attachment. As-cast and as-received brass is characterized for metallurgical and mechanical properties. X-Ray Diffraction pattern analysis shows dominant presence of copper–zinc phase in as-cast brass. Surface morphology of the prepared specimens is studied under electron microscope. Tensile strength of microwave melted as-cast brass is 350.88 MPa in an average, which shows 2.5% improvement than the conventionally melted as-cast brass. Hardness of microwave and conventionally melted as-cast brass are found to be 153.3 and 149.9 Hv respectively, while that of as-received brass is found to be 131.1 Hv. It is observed from the present work that bulk metals can be processed using microwaves, which has resulted in enhancement of the mechanical properties.     

Design and analysis of a CMOS passive Σ∆ ADC for low power RF transceivers

Design and analysis of a Σ∆ modulator with a passive switched capacitor loop filter is presented. Design steps for optimum loop filter design for quantization noise suppression and thermal noise reduction is outlined. Design specifications for sampling clock phase noise, reference buffer and input buffer settling is analyzed. Presented design has a 2nd-order loop filter and uses only metal-metal capacitors and thin oxide digital transistors with no additional components occupying less than 0.1 mm² silicon area in 0.13 μm CMOS digital process. Measurement results show that the ADC achieves 80 dB peak SNR at a 100 kHz integration bandwidth with 1 pJ/sample conversion efficiency. With decimation filter power consumption of 0.22 mW at 104 MHz sampling rate, the ADC consumes only about 1 mA at 1.5 V for each channel.     

Metallurgical Analysis of Cracked AA7075 Aluminum Alloy Component Used in Control System of a Satellite Launch Vehicle

Journal of Failure Analysis and Prevention - High-strength aluminum alloy AA7075 forgings are widely used in various control system components of liquid engines of satellite launch vehicles. In one...     

Reducing the impact of false time out on TCP performance in TCP over OBS networks

Random burst contention losses plague the performance of Optical Burst Switched networks. Such random losses occur even in low load network condition due to the analogous behavior of wavelength and routing algorithms. Since a burst may carry many packets from many TCP sources, its loss can trick the TCP sources to conclude/infer that the underlying (optical) network is congested. Accordingly, TCP reduces sending rate and switches over to either fast retransmission or slow start state. This reaction by TCP is uncalled-for in TCP over OBS networks as the optical network may not be congested during such random burst contention losses. Hence, these losses are to be addressed in order to improve the performance of TCP over OBS networks. Existing work in the literature achieves the above laid objective at the cost of violating the semantics of OBS and/or TCP. Several other works make delay inducing assumptions. In our work, we introduce a new layer, called Adaptation Layer, in between TCP and OBS layers. This layer uses burst retransmission to mitigate the effect of burst loss due to contention on TCP by leveraging the difference between round trip times of TCP and OBS. We achieve our objective with the added advantage of maintaining the semantics of the layers intact.