Channel Estimation for MIMO MC-CDMA Systems

The concepts of MIMO MC-CDMA are not new but the new technologies to improve their functioning are an emerging area of research. In general, most mobile communication systems transmit bits of information in the radio space to the receiver. The radio channels in mobile radio systems are usually multipath fading channels, which cause inter-symbol interference (ISI) in the received signal. To remove ISI from the signal, there is a need of strong equalizer. In this thesis we have focused on simulating the MIMO MC-CDMA systems in MATLAB and designed the channel estimation for them

Humanity in Purananooru

The Purananooru Thokai is unrivaled among the Tamil treasures compiled and preserved by ancient Tamil scholars. It describes the system of rule of the kings of the Sangam age. It makes us aware of the history and culture of the ancient Tamils. The Purananuru helps us to realize the glories of public life. A closer look helps us to understand the position of the Tamils of the time in the fields of political education, ethics, science, literature, music, and fine arts. The Purananooru beautifully highlights the excellence of the Tamils of that time in qualities such as love, grace, friendship, valour, honour, and charitableness. This book highlights the greatness of Kadayezhu Vallals, poets, crowned kings, leaders of small lands, petty chiefs, poets, brave people, etc. Many songs refer to eighteen Chera kings, thirteen Chola kings, and twelve Pandya kings. The Purananooru mentions the good social life of the Tamils, political awakening, hospitality, high morality, firm principles, wearing mangal sutra, installing the middle stone, fasting during widowhood, the shortening of the meal, the burial of the dead in the thali (pot), and the climbing of the funeral pyre of the husband

Efficacy of Topical Ivermectin in comparison to other scabicidal agents

INTRODUCTION: Scabies is a common, intensely pruritic dermatoses caused by the mite Sarcoptes scabiei var hominis. It is highly contagious and transmitted by close skin to skin contact. Scabies remains a major health problem in terms of its contagious nature and the secondary infections which occurs as a result of this disease. AIMS AND OBJECTIVES: Aim of the study was to compare the efficacy of topical ivermectin and other scabicidal agents and to assess the improvement in severity of pruritus and severity of lesions with treatment. MATERIALS AND METHODS: Around 90 scabies patients were selected from the patients attending out patient clinic in dermatology department. After obtaining informed written consent, detailed history and thorough clinical examination of the patients was done. The patients were randomly allotted to one of the three treatment groups- GBHC, Permethrin and Ivermectin group. The treatment response was analysed in all the treatment groups based on reduction in the Severity of pruritus score and Severity of Lesions score. The response was then graded as good, moderate and poor. RESULTS: Mean age of the study population was 27.66 years. Forty seven patients were males (52.2%) and forty three patients were females (47.8%). In Ivermectin group, 86.6% (26 out of 30) patients had good response to treatment whereas in Permethrin group, 36.7% (11 out of 30) patients had good response to treatment. In GBHC group, only 10% (3 out of 30) patients had good response to treatment. Ivermectin compared favourably to the other two drugs with nearly more than three fourths of the patients having significant improvement at an earlier stage while permethrin group had better response after twice application of the medicine when compared to GBHC group. CONCLUSION: From this study, it can be concluded that topical Ivermectin can be considered as first line of treatment modality for scabiesamong other available agents as it causes earlier and maximum response. This study emphasizes the need for finding out newer effective drugs for treating scabies

Automatic organ validation of b-mode ultrasound images for transmission to cloud

Miniaturization in size of Medical ultrasound scanning machine made it to use in point of care applications. Lack of sonographers and their unwillingness to work in rural areas limit the benefits of ultrasound system in rural healthcare. Diagnosis of patients through ultrasound is done by visualizing the ultrasound scanned images of organs. Diagnosis through telemedicine involves transmitting of ultrasound images from rural locations to cloud, where sonographer can remotely access the ultrasound data from cloud and generate the report, thus reducing the geographical separation between patients and doctors. Due to lack of adequate sonographers, ultrasound scanning in remote areas is operated by semi-skilled clinicians. Most of the images generated by semi-skilled clinicians are not useful for diagnosis. Transmitting all these images increases the data in cloud, drains the battery of portable ultrasound machine and increases latency in medication. This paper provides automatic B-mode ultrasound image validation based on organ information present in the image for diagnosis, thus avoiding transmission of invalid images to cloud. Linear kernel SVM classifier trained with first order statistic features of image with/without organs is used to classify the images into valid and invalid for diagnosis. The algorithm resulted with a recognition efficiency of 94.2% in classifying the ultrasound images

Fast Region of Interest detection for fetal genital organs in B-mode ultrasound images

Genital organ detection of fetus in B-mode ultrasound images has a considerable significance. It is useful to know any malformations present in the genital organs and also to determine the sex of the fetus. In this paper we propose a Feature from Accelerated Segment Test (FAST) technique for approximate detection of fetal genitals in ultrasound images. FAST algorithm is capable of producing the corner points at a higher speed which falls on the fetal genital organs. A window of size 60×60 pixels being corner point as a center is considered as Region of Interest (ROI), where genital organ of fetus is anticipated. The efficiency of the algorithm is calculated as the ratio of number of images where corner points are placed on the fetus genital organ to the total number of images tested. FAST algorithm is robust to speckles present in the image, machine independent, fast and also computationally less intensive to implement in real time with an efficiency of 96.7%

Computer-Assisted Algorithms for Ultrasound Imaging Systems

Ultrasound imaging works on the principle of transmitting ultrasound waves into the body and reconstructs the images of internal organs based on the strength of the echoes. Ultrasound imaging is considered to be safer, economical and can image the organs in real-time, which makes it widely used diagnostic imaging modality in health-care. Ultrasound imaging covers the broad spectrum of medical diagnostics; these include diagnosis of kidney, liver, pancreas, fetal monitoring, etc. Currently, the diagnosis through ultrasound scanning is clinic-centered, and the patients who are in need of ultrasound scanning has to visit the hospitals for getting the diagnosis. The services of an ultrasound system are constrained to hospitals and did not translate to its potential in remote health-care and point-of-care diagnostics due to its high form factor, shortage of sonographers, low signal to noise ratio, high diagnostic subjectivity, etc. In this thesis, we address these issues with an objective of making ultrasound imaging more reliable to use in point-of-care and remote health-care applications. To achieve the goal, we propose (i) computer-assisted algorithms to improve diagnostic accuracy and assist semi-skilled persons in scanning, (ii) speckle suppression algorithms to improve the diagnostic quality of ultrasound image, (iii) a reliable telesonography framework to address the shortage of sonographers, and (iv) a programmable portable ultrasound scanner to operate in point-of-care and remote health-care applications

Analytical Model of Adaptive CSMA-CA MAC for Reliable and Timely Clustered Wireless Multi-Hop Communication

Reliability and delay of a single cluster wireless network is well analysed in the literature. Multi-hop communication over the number of clusters is essential to scale the network. Analytical model for reliability and end-to-end delay optimization for multi-hop clustered network is presented in this paper. Proposed model is a three dimensional markov chain. Three dimensions of markov model are the adaptable mac parameters of CSMA-CA. Model assumes wakeup rates for each cluster. Results show that reliability and delay are significantly improved than previous analytical models proposed. It has been observed that overall reliability of multi-hop link is improved, with reduction in end-to-end delay is reduced even at lower wakeup rates of a cluste

Effect of Relay Nodes on End-To-End Delay in Multi-Hop Wireless Ad-Hoc Networks

Channel access delay in a wireless adhoc network is the major source of delay while considering the total end to-end delay. Channel access delays experienced by different relay nodes are different in multi-hop adhoc network scenario. These delays in multi-hop network are analysed in the literature assuming channel access delays are independent and are of same magnitude at all the nodes in the network. In this work, the end to-end delay in a multi-hop adhoc network is analysed taking into account the silent relay nodes. Along with silent relay node effect, Channel access probability (p), transmission radius (r) analogous to transmit power, network throughput and density of nodes arête other factors considered for the end-to-end delay analysis. Effect of network parameters along with silent relay nodes on end-to-end delay is found to be considerably high compared to the previous literature results. Given a bound on end-to-end delay with percentage of silent relay nodes, throughput, node density requirements for a multi-hop adhoc network, optimal ranges of transmission radius and channel access probability can be obtained from the proposed analysis. End-to-end delay increases with silent relay nodes along with transmission radius(r), channel access probability(p), node density and throughput. It is clear from the analysis, that the effect of silent relay nodes on end to-end delay cannot be ignored to maintain certain Quality of service (QoS) metrics for the multi-hop wireless adhoc networ

Effect of relay nodes and transmit power on end-to-end delay in multi-hop wireless ad hoc networks

Channel access delay in a wireless multi-hop ad hoc network is the major source of delay while considering end-to-end delay. In this work, end-to-end delay is analysed considering silent relay nodes and effect of network parameters like node density and throughput. Given network parameter requirements and bound on end-to-end delay, optimal ranges of transmission radius and channel access probability can be obtained from the proposed analysis. Effect of silent relay nodes must be considered to maintain quality of service (QoS) metrics. Transmission power adaptability to reduce end-to-end delay is analysed considering the interference model. Increase in transmission power is not reducing end-to-end delay linearly. Simulation results show that increase in end-to-end delay due to channel access probability and throughput is onsiderably higher than node density. Also given the network parameters, end-to-end delay can be minimised only up to certain value irrespective of increase in transmit power