1,721,143 research outputs found
Hybrid microwave power amplifiers for broadband communication / Pragash Sangaran
No full textThe software-defined radio is the future of radio technology. The development of a broadband power amplifier is the most challenging radio component to design in achieving software-defined radio goals due to the PA gain-bandwidth limitation. The distributed power amplifier (DPA) overcomes the limitation by combining output power from several transistors in an additive fashion. Matrix Amplifier (MA) consists of two or more DPA stacked together in a multiplicative manner. In this project, a high power and high gain DPA for a two-way radio system is demonstrated. The DPA exhibits 10W output power and 32dB gain across the frequency range of 100MHz to 2GHz. The DPA also has an adjustable inter-stage matching cascaded network. A good correlation between measurement and simulation has been achieved. Simulation guidelines to achieve a good correlation between measurement and simulation are also given in this work. On top of that, the design of a high gain silicon BJT and E-pHEMT hybrid matrix amplifier with novel optimum filter matching technique is demonstrated. Conventional DPA and MA design techniques are only suitable for MMIC implementation because the availability of arbitrary values of lumped element Lc, Ld, Lb, and Cadd is only possible in MMIC technology. Therefore, a novel hybrid MA design and implementation methodology using novel optimum filter matching techniques are demonstrated. In this work, MA exhibits an average gain of 37.5 dB and an average Pout of 18 dBm in the band 0.65-5.8 GHz with 3V supply voltage. The gain is the highest among the state-of-the-art devices in the same frequency range. The bandwidth is 5.15 GHz, and P1dB is 20.3 dBm at 1.35 GHz. The PAE ranges from 10 % to 16 %, and Pdc is 1.2 W
Influences of construction features on the dynamic characteristics of joisted timber floors Pragash Sivanandatheva
Get PDFThe resurgence of timber in the construction industry is because of research and development interest and training in various institutions resulting in the development of design codes that address initial concerns including the combustibility of timber. In addition, timber can absorb and retain carbon in its lifetime, thus attracting attention as a major resource for sustaining the environment. One of the effective ways of using timber is in the design and construction of building floors and bridge decks. The advantage of using timber for floors and decks compared to other alternative materials lies in its lightweight. The low mass of timber can influence the overall construction cost. Joisted timber floors (JTF) have been popular due to their simplicity and creating avenues for using panels that can be made from timber by-products.
The low masses of timber floors in relation to their high stiffnesses, make them highly susceptible to vibrations, which cause discomfort in the usage of buildings which embody them. Various studies have been conducted to assess the parameters considered as JTF vibration performance indicators, including frequencies and response amplitudes. However, there appears to be a knowledge gap in how changes in the construction features affect the vibration behaviour of joisted timber floors. It is expected that varying construction variables may significantly affect the floor dynamic characteristics.
This study focuses on assessing how the changes in various construction features of JTF affect their vibration behaviour. Numerical finite element (FE) approach is adopted in which modal models are developed using the commercial software SAP2000.. Calibrated FE modal models are used to evaluate the effect of changing various JTF construction features on the modal characteristics in terms: mode order, modal shapes, natural frequencies and frequency separations. FE models are also used to assess changes in motion responses as floor elements are changed.
Findings clearly show that variations in the floor construction features significantly influence both modal parameter and motion response amplitudes. Reducing joist spacing of a typical floor increases all modal natural frequencies thus, providing a better frequency separation which also explains the reduction in response amplitude. Similar observations are made with changes in features such as thickness in floor sheathing, bridging across the axis of the joist, the number of floor edges supported and the rigidity in connecting floor sheathing and joists
Assessment of noise exposure in indoor firearm shooting range at police headquarters / Pragash Nair Guruvairapan
Get PDFA research study similar to this is cannot be completed anyone alone. Contribution from varies people, in their own ways, have made this achievable. The appreciations to the all contributors are as follows.
Primarily, my sincere gratitude is to my supervisors Dr. Jegalakshmi A/P Jewaratnam, for the countless support in completing this research studies, for their patience, motivation, enthusiasm, and immense knowledge. Their guidance helped me all the time of research and developing this project. Secondly, I would express my appreciation to Associate Prof. Dr. Ting Hua Nong and Dr. Tuan Zaharinie Binti Tuan Zahari for guiding me through Research Methodology course which was a stepping stone to this research.
I would like to express my special thanks to the Royal Malaysian Police, for giving permission and support to conduct the research study at the indoor shooting range. Additionally, my sincere gratitude is to all shooting range staff and shooters who help me to complete the data collection within the time frame.
Last but not least, my appreciation for my family, friends and anyone else for their constant encouragement and support to this project for success
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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