Network Selection Based on Weight Estimation of QoS Parameters in Heterogeneous Wireless Multimedia Networks

Network selection in a heterogeneous wireless environment is a major challenge to ensue seamless mobility across different radio air interfaces. To provide the desired quality of service for a given application in a multimedia environment, different parameters, including delay, bandwidth, packet loss and cost per byte, play an important role in network selection. In this paper, we present a novel algorithm for optimal network selection. A heterogeneous environment consisting of four networks, UMTS, WLAN, GPRS and WiMAX has been considered. We propose a network selection algorithm in which weight estimation for the representative set of the network attributes is computed using entropy and technique for order preference by similarity to ideal solution approach. The numerical results show that the proposed model can be effectively implemented to select the desired network in a heterogeneous environment employing triple-play services.     

Contact resistance characteristics of the low cost CuNiCr thin film resistor system

In this paper an investigation of the use of copper as a contact and interconnecting material for thin film resistors and hybrid circuits is reported. The current-voltage characteristics of Nichrome thin film resistors with copper contacts and the contact resistance of $\text{Cu}\text{NiCr}$ metallizations were measured. The effect of thermal annealing on the contact characteristics was also studied.     

Computer‐aided diagnosis system for the detection of bronchiectasis in chest computed tomography images

A computer‐aided diagnosis (CAD) system has been developed for the detection of bronchiectasis from computed tomography (CT) images of chest. A set of CT images of the chest with known diagnosis were collected and these images were first denoised using Wiener filter. The lung tissue was then segmented using optimal thresholding. The Pathology Bearing Regions (PBRs) were then extracted by applying pixel‐based segmentation. For each PBR, a gray level co‐occurrence matrix (GLCM) was constructed. From the GLCM texture features were extracted and feature vectors were constructed. A probabilistic neural network (PNN) was constructed and trained using this set of feature vectors. The images together with the PBRs and the corresponding feature vector and diagnosis were stored in an image database. Rules for diagnosis and for determining the severity of the disease were generated by analyzing the images known to be affected by bronchiectasis. The rules were then validated by a human expert. The validated rules were stored in the Knowledge Base. When a physician gives a CT image to the CAD system, it first transforms the image into a set of feature vectors, one for each PBR in the image. It then performs the diagnosis using two techniques: PNN and mahalanobis distance measure. The final diagnosis and the severity of the disease are determined by correlating the diagnosis determined by both the techniques in consultation with the knowledge base. The system also retrieves similar cases from the database. Thus, this system would aid the physicians in diagnosing bronchiectasis. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 290–298, 2009     

A fast and efficient computer aided diagnostic system to detect tumor from brain magnetic resonance imaging

In this work, a simple and efficient CAD (computer‐aided diagnostic) system is proposed for tumor detection from brain magnetic resonance imaging (MRI). Poor contrast MR images are preprocessed by using morphological operations and DSR (dynamic stochastic resonance) technique. The appropriate segmentation of MR images plays an important role in yielding the correct detection of tumor. On examination of three views of brain MRI, it was visible that the region of interest (ROI) lies in the middle and its size ranges from 240 × 240 mm² to 280 × 280 mm². The proposed system makes effective use of this information and identifies four blocks from the desired ROI through block‐based segmentation. Texture and shape features are extracted for each block of all MRIs in the training set. The range of these feature values defines the threshold to distinguish tumorous and nontumorous MRIs. Features of each block of an MRI view are checked against the threshold. For a particular feature, if a block is found tumorous in a view, then the other views are also checked for the presence of tumor. If corresponding blocks in all the views are found to be tumorous, then the MRI is classified as tumorous. This selective block processing technique improves computational efficiency of the system. The proposed technique is well adaptive and fast, and it is compared with well‐known existing techniques, like k‐means, fuzzy c‐means, etc. The performance analysis based on accuracy and precision parameters emphasizes the effectiveness and efficiency of the proposed work.     

Performance Analysis of Combined Space Time Block Coding with Generalized Selection Combining in Underlay Cognitive Radio

Wireless Personal Communications - In this paper, we demonstrate the performance analysis of an underlay MIMO cognitive radios employing space time block coding at secondary’s user...     

On the Microstructure and Wear Behavior of Fe–xCr–4Mn–3C Hardfacing Alloys

The present paper describes an investigation aimed at evaluating the microstructural and dry sliding adhesive wear characteristics of Fe–xCr–4Mn–3C hardfacing alloys applied through shielded metal arc welding. The effect of chromium addition on the microstructure of hardfacings was carried out by using optical microscope, field emission scanning electron microscope and X-ray mapping. Dry sliding wear tests were performed on a pin-on-disc wear tribometer. From the experimental results, it was observed that the primary carbides were refined and increased with the increase of chromium content. The morphology of carbides revealed that the primary carbides were rod shaped. The increased chromium content was also found to be beneficial to enhance hardness and wear resistance of hardfacings. The correlation between hardness and wear resistance exhibited the reliability of hardness as an indicator of the wear performance of hardfacings.     

Numerical simulation and modelling of a novel MEMS capacitive accelerometer based microphone for fully implantable hearing aid

Microsystem Technologies - The present work proposes a novel MEMS capacitive accelerometer based microphone with enhanced sensitivity. The accelerometer design is simulated in COMSOL MULTIPHYSICS...     

Development and gamma scintigraphy evaluation of gastro retentive calcium ion-based oral formulation: an innovative approach for the management of gastro-esophageal reflux disease (GERD)

Calcium chloride is an essential calcium channel agonist which plays an important role in the contraction of muscles by triggering calcium channel. First time hypothesized about its role in the treatment of GER (gastro-esophageal reflux) and vomiting disorder due to its local action. There are two objectives covered in this study as first, the development and optimization of floating formulation of calcium chloride and another objective was to evaluate optimized formulation through gamma scintigraphy in human subjects. Gastro retentive formulation of calcium chloride was prepared by direct compression method. Thirteen tablet formulations were designed with the help of sodium chloride, HPMC-K4M, and carbopol-934 along with effervescing agent sodium bicarbonate and citric acid. Formulation (F8) fitted best for Korsmeyer–Peppas equation with an R² value of 0.993. The optimized formulation was radiolabelled with ^99mTc-99?m pertechnetate for its evaluation by gamma scintigraphy. Gastric retention (6?h) was evaluated by gamma scintigraphy in healthy human subjects and efficacy of present formulation confirmed in GER positive human subjects. Gamma scintigraphy results indicated its usefulness in order to manage GERD. Stability studies of the developed formulation were carried out as per ICH guidelines for region IV and found out to be stable for 24?months.     

Phenolic triazine (PT) resins. I. Gelation phenomenon studied by calorimetric,mechanical, and dielectric techniques

Gelation phenomenon in thermoset polymers is an area of extreme importance from the processing point of view. Gel point (GP) has traditionally been detected using rheological and mechanical techniques. We wish to report the use of dielectric and especially calorimetric techniques for detecting GP. Using a particular thermoset system, we have compared the calorimetric, dielectric, and mechanical techniques and shown how to define GP in terms of time and temperature. As a matter of convenience, we have briefly defined the gelation phenomenon in thermosets, its significance and measurement, and a critical evaluation of the techniques for detecting GP.     

Spinal epidural abscess: evaluation of factors influencing outcome

OBJECTIVE: The goal of this study was to critically evaluate the predictive efficacy of various clinical factors in spinal epidural abscess influencing outcome after surgical and/or medical treatment. METHODS: A retrospective analysis of 41 cases of spinal epidural abscess treated at Henry Ford Hospital between 1984 and 1992 was performed. RESULTS: Thirty patients underwent open surgery and received antibiotic therapy, and 11 patients received medical treatment alone. After a mean follow-up period of 20.9 months (range, 4-45 mo), 24 patients (58.5%) had no or minimal deficits, 9 patients (22%) had severe paresis or plegia and/or bowel/bladder dysfunction, and 8 patients (19.5%) died. Univariate analysis revealed patient age, degree of thecal sac compression, spinal location, surgical findings, and septic presentation to be significantly associated with outcome. In multiple logistic regression analysis, increasing age and degree of thecal sac compression were the only factors with significant independent association with poor outcome (P = 0.01 for both). A simple grading system (Grades 0-III) was developed, with patient age, degree of thecal sac compression, and duration of symptoms as the determining criteria. The incidence of poor outcome for patients with Grade 0 was 0%, compared to 85.7% for patients with Grade III. CONCLUSION: We conclude that long-term outcome after treatment of spinal epidural abscess can be predicted with the use of the proposed grading scheme. Surgical drainage plus parenterally administered antibiotics remains the recommended treatment, although medical treatment alone can also be used for certain patients.