Energy Efficient Routing Algorithms for Wireless Sensor Networks and Performance Evaluation of Quality of Service for IEEE 802.15.4 Networks

The popularity of Wireless Sensor Networks (WSN) have increased tremendously in recent time due to growth in Micro-Electro-Mechanical Systems (MEMS) technology. WSN has the potentiality to connect the physical world with the virtual world by forming a network of sensor nodes. Here, sensor nodes are usually battery-operated devices, and hence energy saving of sensor nodes is a major design issue. To prolong the network‘s lifetime, minimization of energy consumption should be implemented at all layers of the network protocol stack starting from the physical to the application layer including cross-layer optimization. In this thesis, clustering based routing protocols for WSNs have been discussed. In cluster-based routing, special nodes called cluster heads form a wireless backbone to the sink. Each cluster heads collects data from the sensors belonging to its cluster and forwards it to the sink. In heterogeneous networks, cluster heads have powerful energy devices in contrast to homogeneous networks where all nodes have uniform and limited resource energy. So, it is essential to avoid quick depletion of cluster heads. Hence, the cluster head role rotates, i.e., each node works as a cluster head for a limited period of time. Energy saving in these approaches can be obtained by cluster formation, cluster-head election, data aggregation at the cluster-head nodes to reduce data redundancy and thus save energy. The first part of this thesis discusses methods for clustering to improve energy efficiency of homogeneous WSN. It also proposes Bacterial Foraging Optimization (BFO) as an algorithm for cluster head selection for WSN. The simulation results show improved performance of BFO based optimization in terms of total energy dissipation and no of alive nodes of the network system over LEACH, K-Means and direct methods. IEEE 802.15.4 is the emerging next generation standard designed for low-rate wireless personal area networks (LR-WPAN). The second part of the work reported here in provides performance evaluation of quality of service parameters for WSN based on IEEE 802.15.4 star and mesh topology. The performance studies have been evaluated for varying traffic loads using MANET routing protocol in QualNet 4.5. The data packet delivery ratio, average end-to-end delay, total energy consumption, network lifetime and percentage of time in sleep mode have been used as performance metrics. Simulation results show that DSR (Dynamic Source Routing) performs better than DYMO (Dynamic MANET On-demand) and AODV (Ad–hoc On demand Distance Vector) routing protocol for varying traffic loads rates

Giant aneurysm of internal carotid artery presenting features of retrobulbar neuritis

We report the case of a man who presented with in the features of left optic nerve compression. CT scan and carotid angiography demonstrated an unruptured giant aneurysm of the left internal carotid artery possibly kinking the optic nerve. Carotid ligation in the neck saved both life and vision

Clinical Presentation and Categorisation of Chronic Low Back Pain: A Cross-sectional Analysis of 1000 Outpatients in Eastern India

Introduction: Low back pain is one of the most common presenting symptom among patients seeking medical help, accounting for approximately 85% of the cases. It affects individuals of all age groups and genders. Predominantly back pain is non specific, lacking identifiable patho-anatomy, while a lesser-known type, specific low back pain, demonstrates identifiable aetiology and pathology. This poses a challenge for physicians, as they must not only determine the underlying cause but also formulate categorical treatments for Chronic Low Back Pain (CLBP). Aim: To assess the prevalence of different types of CLBP based on clinical examination, past history, age, and gender in the overall population of the study. Materials and Methods: A cross-sectional study was conducted at Kalinga Institute of Medical Sciences (KIMS), Bhubaneswar, Odisha, India, from August 2019 to July 2021. A total of 1,640 patients were examined in the orthopedics outpatient department, of which 1,000 patients aged between 20 and 60 years, with back pain lasting three months, were included in the study. All patients underwent a detailed clinical evaluation, including history and physical examination. The final type of CLBP was determined based on the predominant symptom. Data analysis was performed using Microsoft Excel software. Results: The male-to-female ratio was 1.23:1, and the average age was 43.1 years. The most common type of CLBP was neuropathic (n=473, 47.3%), followed by discogenic CLBP (n=255, 25.5%). The least common type was coccydynia (n=4, 0.4%). Facetogenic CLBP had the highest average age of presentation (57.3 years), while postural CLBP had the lowest average age (29.6 years). Conclusion: Neuropathic CLBP was the most common type, followed by discogenic CLBP, with sacroiliitis and coccydynia being less common. Detailed clinical evaluation aids in classifying different types of CLBP, which can help avoid unnecessary investigations, except for the neuropathic type and, to some extent, instability CLBP

An unusual orbito-cranial foreign body

The rarity of orbito-cranial gun shot injury in both war and civilian practice has been reported. In a large series of 351 missile head injuries in the Vietnam war, orbital penetration was noted in 0.6% cases only. Review of literature shows that orbital injury was ipsilateral to the cerebral injury in most reported cases. We have previously reported a rare case of left parieto-occipital lobe injury due to gun shot wound of the contralateral (right) orbit. The case reported here sustained a bullet injury to the left frontal bone but the missile was located below the contralateral (right) optic canal. The rarity of the case prompted this report

Mathematical model of complex weld penetration profile: A case of square AC waveform arc welding

A new mathematical model of complex weld bead shape is presented. An ‘offsetting bi-elliptical’ model is constituted that can capture complex geometric features such as observed in square waveform welds vis-à-vis deeper central core and shallow sides with two visually distinct weld zones. The model elucidates new observations on electrode melting and weld bead formation in alternating current waveform submerged arc welding visualised through in-situ radiography imaging. The geometric attributes of constituent ellipses as function of welding process parameters are obtained with inverse modelling. The model yields high degree of accuracy in predication of bead parameters i.e. bead width, depth of penetration, bay angle and bay length for a wide range of process parameters such as EN ratio (% time an electrode remains negative) and wire-feed speed under different chemical composition of shielding flux. The investigation indicates that electrode melting and weld penetration are integrated outcomes of arc phenomena that is influenced by flux chemistry. The findings of present investigations are accomplished enough to be horizontally deployed to develop or improve existing weld bead models