Ultrafast Echocardiography

Grâce à son accessibilité, sa polyvalence et sa sécurité, l'échocardiographie est devenue la technique d'imagerie la plus utilisée pour évaluer la fonction cardiaque. Au vu du succès de l'échographie ultrarapide par ondes planes des techniques similaires pour augmenter la résolution temporelle en échocardiographie ont été mise en oeuvre. L’augmentation de la résolution temporelle de l’échographie cardiaque au-delà des valeurs actuellement atteignables (~ 60 à 80 images par secondes), pourrait être utilisé pour améliorer d’autres caractéristiques de l'échocardiographie, comme par exemple élargir la plage de vitesses détectables en imagerie Doppler couleur limitées par la valeur de Nyquist. Nous avons étudié l'échocardiographie ultrarapide en utilisant des fronts d’ondes ultrasonores divergentes. La résolution temporelle atteinte par la méthode d'ondes divergentes a permis d’améliorer les capacités des modes d’échocardiographie en mode B et en Doppler couleur. La résolution temporelle de la méthode mode B a été augmentée jusqu'à 633 images par secondes, tout en gardant une qualité d'image comparable à celle de la méthode d’échocardiographie conventionnelle. La vitesse de Nyquist de la méthode Doppler couleur a été multipliée jusqu'à 6 fois au delà de la limite conventionnelle en utilisant une technique inspirée de l’imagerie radar; l’implémentation de cette méthode n’aurait pas été possible sans l’utilisation de fronts d’ondes divergentes. Les performances avantageuses de la méthode d'échocardiographie ultrarapide sont supportées par plusieurs résultats in vitro et in vivo inclus dans ce manuscrit.

Grain refinement studies on Mg and Mg-Al based alloys

Demand on magnesium and its alloys is increased significantly in the automotive industry because of their great potential in reducing the weight of components, thus resulting in improvement in fuel efficiency of the vehicle. To date, most of Mg products have been fabricated by casting, especially, by die-casting because of its high productivity, suitable strength, acceptable quality & dimensional accuracy and the components produced through sand, gravity and low pressure die casting are small extent. In fact, higher solidification rate is possible only in high pressure die casting, which results in finer grain size. However, achieving high cooling rate in gravity casting using sand and permanent moulds is a difficult task, which ends with a coarser grain nature and exhibit poor mechanical properties, which is an important aspect of the performance in industrial applications. Grain refinement is technologically attractive because it generally does not adversely affect ductility and toughness, contrary to most other strengthening methods. Therefore formation of fine grain structure in these castings is crucial, in order to improve the mechanical properties of these cast components. Therefore, the present investigation is “GRAIN REFINEMENT STUDIES ON Mg AND Mg-Al BASED ALLOYS”. The primary objective of this present investigation is to study the effect of various grain refining inoculants (Al-4B, Al- 5TiB2 master alloys, Al4C3, Charcoal particles) on Pure Mg and Mg-Al alloys such as AZ31, AZ91 and study their grain refining mechanisms. The second objective of this work is to study the effect of superheating process on the grain size of AZ31, AZ91 Mg alloys with and without inoculants addition. In addition, to study the effect of grain refinement on the mechanical properties of Mg and Mg-Al alloys. The thesis is well organized with seven chapters and the details of the studies are given below in detail.

Evaluation of cyanobacteria for biomass production and effluent treatment

The microalgae gained importance as food and feed as well as source of fine chemicals since the l960’s. Spirulina became the trend setter due to its easily culturable properties as well as nutritional composition. A rapid expansion of microalgal industry occurred in the Asia-Pacific region as microalgae came to stay as a health food supplement. Microalgae have been an integral component of oxidation ponds usually incorporated with wastewater treatment. Over the last few decades, efforts have been made to apply intensive microalgal cultures to perform biological tertiary treatment of secondary effluents. Given the limited number of species still available for commercial exploitation, it is imperative to isolate and cultivate those photosynthetic organisms with high growth rate and biomass accumulation, which could play the dual role of cleaning the wastewater and also providing useful biomass. This has been the objective of this study ie. 0 To develop pure cultures of local isolates of Cyanobacteria for extraction of biochemicals of commercial value 0 To couple biomass production with effluent treatment

Mobility Metric based LEACH-Mobile Protocol

Cluster based protocols like LEACH were found best suited for routing in wireless sensor networks. In mobility centric environments some improvements were suggested in the basic scheme. LEACH-Mobile is one such protocol. The basic LEACH protocol is improved in the mobile scenario by ensuring whether a sensor node is able to communicate with its cluster head. Since all the nodes, including cluster head is moving it will be better to elect a node as cluster head which is having less mobility related to its neighbours. In this paper, LEACH-Mobile protocol has been enhanced based on a mobility metric “remoteness” for cluster head election. This ensures high success rate in data transfer between the cluster head and the collector nodes even though nodes are moving. We have simulated and compared our LEACH-Mobile-Enhanced protocol with LEACHMobile. Results show that inclusion of neighbouring node information improves the routing protocol.

RRNS-convolutional encoded concatenated code for OFDM based wireless communication

The modern telecommunication industry demands higher capacity networks with high data rate. Orthogonal frequency division multiplexing (OFDM) is a promising technique for high data rate wireless communications at reasonable complexity in wireless channels. OFDM has been adopted for many types of wireless systems like wireless local area networks such as IEEE 802.11a, and digital audio/video broadcasting (DAB/DVB). The proposed research focuses on a concatenated coding scheme that improve the performance of OFDM based wireless communications. It uses a Redundant Residue Number System (RRNS) code as the outer code and a convolutional code as the inner code. The bit error rate (BER) performances of the proposed system under different channel conditions are investigated. These include the effect of additive white Gaussian noise (AWGN), multipath delay spread, peak power clipping and frame start synchronization error. The simulation results show that the proposed RRNS-Convolutional concatenated coding (RCCC) scheme provides significant improvement in the system performance by exploiting the inherent properties of RRNS.

“Design and Development of Coplanar Strip Fed Planar Antennas”

With the recent progress and rapid increase in the field of communication, the designs of antennas for small mobile terminals with enhanced radiation characteristics are acquiring great importance. Compactness, efficiency, high data rate capacity etc. are the major criteria for the new generation antennas. The challenging task of the microwave scientists and engineers is to design a compact printed radiating structure having broadband behavior along with good efficiency and enhanced gain. Printed antenna technology has received popularity among antenna scientists after the introduction of planar transmission lines in mid-seventies. When we view the antenna through a transmission line concept, the mechanism behind any electromagnetic radiator is quite simple and interesting. Any electromagnetic system with a discontinuity is radiating electromagnetic energy. The size, shape and orientation of the discontinuities control the radiation characteristics of the system such as radiation pattern, gain, polarization etc. It can be either resonant or non-resonant. This thesis deals with antennas that are developed from a class of transmission lines known as coplanar strip-CPS, a planar analogy of parallel pair transmission line. The specialty of CPS is its symmetric structure compared to other transmission lines, which makes the antenna structures developed from CPS quite simple for design and fabrication. The structural modifications on either metallic strip of CPS results in different antennas. The first part of the thesis discusses a single band and dual band design derived from open ended slot lines which are very much suitable for 2.4 and 5.2 GHz WLAN applications. The second section of the study is vectored into the development of enhanced gain dipoles. A single band dipole and a wide band enhanced gain dipole suitable for 5.2/5.8 GHZ band and imaging applications are developed and discussed. Last part of the thesis discusses the development of directional UWBs. Three different types of ultra-compact UWBs are developed and almost all the frequency domain and time domain analysis of the structures are discussed.

Mobility Metric based LEACH-Mobile Protocol

Cluster based protocols like LEACH were found best suited for routing in wireless sensor networks. In mobility centric environments some improvements were suggested in the basic scheme. LEACH-Mobile is one such protocol. The basic LEACH protocol is improved in the mobile scenario by ensuring whether a sensor node is able to communicate with its cluster head. Since all the nodes, including cluster head is moving it will be better to elect a node as cluster head which is having less mobility related to its neighbours. In this paper, LEACH-Mobile protocol has been enhanced based on a mobility metric “remoteness” for cluster head election. This ensures high success rate in data transfer between the cluster head and the collector nodes even though nodes are moving. We have simulated and compared our LEACH-Mobile-Enhanced protocol with LEACHMobile. Results show that inclusion of neighbouring node information improves the routing protocol.

Unconstrained Handwritten Malayalam Character Recognition using Wavelet Transform and Support vector Machine Classifier

This paper presents the application of wavelet processing in the domain of handwritten character recognition. To attain high recognition rate, robust feature extractors and powerful classifiers that are invariant to degree of variability of human writing are needed. The proposed scheme consists of two stages: a feature extraction stage, which is based on Haar wavelet transform and a classification stage that uses support vector machine classifier. Experimental results show that the proposed method is effective

Pattern Analysis Techniques for the Recognition of Unconstrained Handwritten Malayalam Character Images

The objective of the study is to develop a hand written character recognition system that could recognisze all the characters in the mordern script of malayalam language at a high recognition rate

Hybrid Background Subtraction in Video using Bi-level CodeBook Model

Detection of Objects in Video is a highly demanding area of research. The Background Subtraction Algorithms can yield better results in Foreground Object Detection. This work presents a Hybrid CodeBook based Background Subtraction to extract the foreground ROI from the background. Codebooks are used to store compressed information by demanding lesser memory usage and high speedy processing. This Hybrid method which uses Block-Based and Pixel-Based Codebooks provide efficient detection results; the high speed processing capability of block based background subtraction as well as high Precision Rate of pixel based background subtraction are exploited to yield an efficient Background Subtraction System. The Block stage produces a coarse foreground area, which is then refined by the Pixel stage. The system’s performance is evaluated with different block sizes and with different block descriptors like 2D-DCT, FFT etc. The Experimental analysis based on statistical measurements yields precision, recall, similarity and F measure of the hybrid system as 88.74%, 91.09%, 81.66% and 89.90% respectively, and thus proves the efficiency of the novel system.

Social Structural Determinants of Education among Tribes in Kerala

The study is focused on education of tribes particularly the problem of high dropout rate existing among the tribal students at school level. Scheduled Tribe is one of the marginalized communities experiencing high level of educational deprivation. The analysis of the study shows that the extent of deprivation existing among STs of Kerala is much higher compared to that of other communities. The present study covered tribes of three tribal predominant districts of Kerala such as Idukki, Palakkad and Wayanad. Out of the 35 tribal communities in the State, 17 of them are concentrated in these districts. Tribes concentrated in Idukki include Muthuvans, Malai Arayan, Uraly, Mannan and Hill Pulaya. The present study analyzed dropouts situation in tribal areas of Kerala by conducting Field Survey among dropout and non-dropout students at school level. High dropouts among STs persist due to many problems which are of structural in nature. Important problems faced by the tribal students that have been analyzed, this can be classified as economic, social, cultural and institutional. It is found that there exists high correlation between Income and expenditure of the family with the well-being of individuals. Significant economic factors are poverty and financial indebtedness of the family. Some of the common cultural factors of tribes are Nature of Habitation, Difference in Dialect and Medium of Instruction etc. Social factors analyzed in the study are illiteracy of parents, migration of family, family environment, motivation by parents, activities engaged in for helping the family and students’ lack of interest in studies. The analysis showed that all these factors except migration of the family, are affecting the education of tribal students. Apart from social, economic and cultural factors, there are a few institutional factors which will also influence the education of tribal students. Institutional factors analyzed in the study include students’ absenteeism, irregularity of teachers, attitude of non-tribal teachers and non-tribal students, infrastructure facilities and accessibility to school. The study found irregularity of students and accessibility to school as significant factors which determine the dropout of the students.

Large-Size AlGaN/GaN HEMT Large-Signal Electrothermal Characterization and Modeling for Wireless Digital Communications

The rapid growth in high data rate communication systems has introduced new high spectral efficient modulation techniques and standards such as LTE-A (long term evolution-advanced) for 4G (4th generation) systems. These techniques have provided a broader bandwidth but introduced high peak-to-average power ratio (PAR) problem at the high power amplifier (HPA) level of the communication system base transceiver station (BTS). To avoid spectral spreading due to high PAR, stringent requirement on linearity is needed which brings the HPA to operate at large back-off power at the expense of power efficiency. Consequently, high power devices are fundamental in HPAs for high linearity and efficiency. Recent development in wide bandgap power devices, in particular AlGaN/GaN HEMT, has offered higher power level with superior linearity-efficiency trade-off in microwaves communication. For cost-effective HPA design to production cycle, rigorous computer aided design (CAD) AlGaN/GaN HEMT models are essential to reflect real response with increasing power level and channel temperature. Therefore, large-size AlGaN/GaN HEMT large-signal electrothermal modeling procedure is proposed. The HEMT structure analysis, characterization, data processing, model extraction and model implementation phases have been covered in this thesis including trapping and self-heating dispersion accounting for nonlinear drain current collapse. The small-signal model is extracted using the 22-element modeling procedure developed in our department. The intrinsic large-signal model is deeply investigated in conjunction with linearity prediction. The accuracy of the nonlinear drain current has been enhanced through several issues such as trapping and self-heating characterization. Also, the HEMT structure thermal profile has been investigated and corresponding thermal resistance has been extracted through thermal simulation and chuck-controlled temperature pulsed I(V) and static DC measurements. Higher-order equivalent thermal model is extracted and implemented in the HEMT large-signal model to accurately estimate instantaneous channel temperature. Moreover, trapping and self-heating transients has been characterized through transient measurements. The obtained time constants are represented by equivalent sub-circuits and integrated in the nonlinear drain current implementation to account for complex communication signals dynamic prediction. The obtained verification of this table-based large-size large-signal electrothermal model implementation has illustrated high accuracy in terms of output power, gain, efficiency and nonlinearity prediction with respect to standard large-signal test signals.

Ist der Ernährungsführerschein eine geeignete Primärpräventionsmaßnahme, um die Ernährungssituation zu verbessern?

Das Ernährungsverhalten einer Bevölkerung hat einen wesentlichen Einfluss auf das Wohlbefinden, die Gesundheit und Leistungsfähigkeit der Menschen. Ernährungsbedingte, chronische Erkrankungen weisen in den westlichen Industrienationen eine hohe Inzidenz und Prävalenz auf. Präventionsmaßnahmen im Setting Schule sollen das Ernährungsverhalten der Kinder- und Jugendlichen positiv beeinflussen. Gerade in diesem Setting können Personen mit unterschiedlichem sozioökonomischem Status, sowie Personen aus diversen Lebensbereichen angesprochen werden. Der Ernährungsführerschein (EFS) ist eine schulbasierte Primärpräventions-maßnahme, der in der 3. Jahrgangsstufe/Grundschule durchgeführt wird. In 6 – 7 Unterrichtseinheiten erfolgt eine praxisnahe Vermittlung von Grundkenntnissen über Ernährung, Lebensmittel und deren Zubereitung. Der EFS möchte eine Verhaltensänderung der Schulkinder bewirken. Sie erlernen Kompetenzen, damit sie in der Lage sind, sich selbst eine gesunde Mahlzeit zubereiten zu können. Aber kann dieses Projekt eine nachhaltige Verhaltensänderung bewirken? Die folgende Studie mit Mixed-Methods-Ansatz im Explanatory-Sequential-Design versucht genau dieser Frage nachzugehen. Auf eine quantitative Prä- und Postbefragung in 16 Klassen an 12 Grundschulen im Landkreis Marburg Biedenkopf und insgesamt 992 Befragungen folgte eine qualitative Studie mit neun problemzentrierten, leitfadengestützten Interviews. Der EFS zeigt keinen signifikanten Einfluss auf die Veränderung des Ernährungsverhaltens. Positiv zu bewerten ist, dass durch den EFS Alltagskompetenzen bei der Nahrungszubereitung gefördert wurden. Dieser positive Einfluss muss jedoch differenziert betrachtet werden, denn die qualitativen Studie zeigt, dass der EFS sehr gut in Familien aufgenommen wird, die sich bereits mit Ernährungsfragen auseinandersetzen und darauf achten, einen ernährungsphysiologisch günstigen Ernährungsstil zu leben oder anzustreben. In Familien der Billig- und Fleischesser konnte der EFS die Türen nicht öffnen. Aber gerade in diesem Segment wäre eine Veränderung des Essverhaltens induziert. Die Untersuchung ergab, dass der EFS für sich alleine nicht den Anspruch erheben kann, die Ernährungssituation der Kinder und Familien zu verbessern. Aber er bietet ein methodisch-didaktisch gut ausgearbeitetes Konzept und könnte als Baustein in die Entwicklung eines praxisnahen, erlebnisorientierten und ganzheitlichen Ernährungsbildungskonzepts unter Berücksichtigung diverser Settings und Lebenswelten der Kinder und Familien einfließen.

Evaluación a largo plazo en mujeres tratadas con laser para depilación facial en uniláser medica

El vello facial no deseado es un problema común en las mujeres, los tratamientos láser han mostrado efectividad para su manejo. Objetivo: Evaluar los resultados de la depilación láser en cara de las pacientes tratadas a largo plazo (20 sesiones o más ) luego de un seguimiento de 6 meses durante los años 1997 y 2012. Metodología: 55 mujeres que con tipo de piel II a V recibieron 20 o más sesiones de láser con seguimiento mayor a 6 meses posterior al la última sesión. Resultados: la edad promedio fue (32 ± 9,3 años), el 18,2 % presentaban SOP o Hiperandrogenismo el número de sesiones en cara fue de (30,84 ± 12,132), un promedio de disparos de (6,330 ± 7,804), los Kilojulios acumulados tuvieron un promedio de (126,5 ± 161,4) la fluencia promedio fue (18,5 ± 3,2 Julios/cm2), el láser de Alexandrita fue utilizado en el 98% de las pacientes. Se encontró cambios significativos entre el conteo inicial y el final de vello facial (484,9 ± 568.9 (med=300) vs. 103,33± 138,63 (med=60), p<0.001, Test de Wilcoxon). El 32.7% mostraron reducción > 90% (5,5% reducción del 100%). Conclusión : El tratamiento con de depilación con láser mostro una reducción significativa del vello facial, en mujeres mayores de 14 años con un tratamiento a largo plazo (20 sesiones o más), con una tasa de reducción mayor del 90% en 32.7% de las pacientes y un promedio de reducción del grupo de 79,36 ±15,51 %, similar a lo reportado en los diferentes estudios (77%).

More women in informatics research and education

Speaker: Lynda Hardman Organiser: Time: 04/02/2015 12:30-13:30 Location: B32/3077 Abstract The challenges of addressing gender inequalities in science, technology, engineering, mathematics and medicine is widely acknowledged. We currently hold a bronze award and ECS is one of many academic units in the University which has gained Athena Swan Charter status. In this seminar, Professor Lynda Hardman, Chair of the Informatics Europe working group "Women in Informatics Research and Education” will be explaining the causes of issued underlying gender inequality and constructive routes to addressing this important agenda. In undertaking to commit to an action plan which is a prerequisite of gaining charter status, the University or academic department agreed to accept and incorporate the Athena Swan six principles listed below: * To address gender inequalities requires commitment and action from everyone, at all levels of the organisation * To tackle the unequal representation of women in science requires changing cultures and attitudes across the organisation * The absence of diversity at management and policy-making levels has broad implications which the organisation will examine * The high loss rate of women in science is an urgent concern which the organisation will address * The system of short-term contracts has particularly negative consequences for the retention and progression of women in science, which the organisation recognises * There are both personal and structural obstacles to women making the transition from PhD into a sustainable academic career in science, which require the active consideration of the organisation. This seminar is designed to provide an opportunity to explore these issues NOTE: Lynda will be basing here talk on some of the work she directed as chair of the "Women in Informatics Research and Education” working group. The purpose of the working group is to actively participate and promote actions that contribute to improve gender balance in Information and Communication Sciences and Technologies. The first concrete result of the working group's activities was the publication of the booklet "More Women in Informatics Research and Education" in 2013. The booklet is a compact source of clear and simple best practices to deans and heads of departments that aim to increase the participation of women as both students and employees in their institutions. Many tips included were also inspired by colleagues already in leading positions who have already implemented actions in their institutions to attract more women and ensure their continued participation in the organization at commensurate ratios with their male colleagues. The booklet is endorsed by the European Commission and features a foreword by Neelie Kroes, Vice-President of the European Commission, responsible for the Digital Agenda.