1,721,196 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Acoustic simulation and characterization of capacitive micromachined ultrasonic transducers
No full textIn this thesis, simulation and characterization methods for capacitive micro machined ultrasonic transducers (CMUT) useable for application development are shown. A nonlinear simulation model for CMUT cells is implemented, which allows to find the best CMUT design by a genetic optimization procedure. For the verification of fabricated CMUTs against simulation results and specification sheets, acoustic measurement procedures for the characterization of CMUT cell designs are developed. They are based on decoupling the sound field from the individual cell characteristics to measure the send- and receive sensitivity of CMUTs. Another possibility to assess the acoustic characteristics is the electrical impedance measurement. A nonlinear analytic model for the electrical impedance of CMUT is invented and used for design evaluation. A wafer level test procedure for an end-of-line quality assurance based on electrical impedance measurements closes the loop from simulation to fabricated CMUT. The thesis finished with further ideas for improving the CMUT technology and measurement procedures
Activity Recognition On Unmodified Consumer Smartphones Via Active Ultrasonic Sensing
No full textSensor miniaturisation and streaming classification techniques can be used to recognize human behaviours and contexts. This is extremely valuable to realize smart environments, e.g. to support healthy and independent living. The most important parameters to sense include indoor location, gestures, or emergencies like falls. Up to now, activity recognition systems face a number of sensitive drawbacks. For example, camera-based systems induce privacy issues and are costly to deploy. Body-worn systems are inconvenient to wear over long periods of time. Highly visible systems may introduce social stigma and modify the well-known living environment. In this project, we explore the possibility for the use of a new, unobtrusive, physical principle to sense and recognize human activities using off-the-shelf smart-phone. A person's smart-phone is a cornucopia of information. The huge variety of sensors in today's mobile phones makes these devices a prime target for human activity recognition. Our novel approach is to develop a novel activity recognizing system using an unmodified smart-phone. We profit from integrated microphones and loudspeakers without additional hardware components needed. The advantage of this system is therefore that it can be easily installed on a smart-phone and put into action. An android application has already been developed which is able to send a high frequency sound in the near ultrasound range, e.g. 20 kHz. Using the received echo from the microphone, the information caused by movement in midair around the device will be extracted. In this thesis we intend to improve the performance of the existing system with respect to noise cancellation and other classification schemes. In this thesis, we present an android application called Trainer for complex activity recognition. It is built on ultrasense [8], a mobile application that capitalizes the characters of ultrasound to inspect the surrounding environment. The application is able to send a high frequency signal in the near ultrasound range, e.g. 20 kHz. Using the received echo from the microphone, the information caused by movement in midair around the device will be extracted. Complex activities tagged under home exercises are evaluated using micro-Doppler signatures [mD-signatures]. We propose an algorithm to classify a set of exercises carried out by the user and show that using the Support vector machine classifier we are able to obtain an accuracy of 85% using Principal component analysis and a signature feature introduced in this thesis as a feature
Additive Fertigung auf Chipoberflächen
No full textRecent advances in additive manufacturing offer promising opportunities for the fabrication of structures on existing micro-(opto-acoustic )electro-mechanical systems, i.e., chips. This is of particular significance in research and development due to the adaptability and adaptation speed of additive manufacturing. These advantages provide the ability to individualize the fabrication of structures and to enable the rapid prototyping approach. The combination of additive manufacturing on chip already enables current research, especially in photonic and microfluidic fields. Despite this, additive manufacturing on chip has never been applied to acoustic sensors or micro-positioning chips. Such devices could benefit from the mentioned advantages, especially for the fabrication of beam shaping waveguides, packaging, grating and end effector structures. Additive manufacturing by two-photon polymerization lithography gathers interest in industry and research due to its capabilities for the fabrication of structures with minimum feature sizes beyond the diffraction limit. The objective of this work is the investigation of additive manufacturing on chip by two-photon polymerization lithography at the example of an acoustic sensor and a micro-positioning chip. One of the greatest challenges is posed by the optical, thermodynamic, adhesion and alignment effects, which are introduced to the fabrication process by these complex substrates. Optical and thermodynamic models were established, and simulations were performed, culminating in a compensation method to address these effects, which was verified by parameter studies. The substrate alignment was investigated via optical technique, resulting in the development, manufacturing and verification of a novel alignment upgrade to the fabrication system employed in this work. The influence of process materials posed another challenge, as they led to chip performance alterations and restrictions. Chips treated with these materials were characterized, e.g., using high frequency optical microphones. Owing to the high precision of the alignment upgrade and the compensation method developed in this work, additive manufacturing on chip using two-photon polymerization lithography on the investigated devices was reported for the first time and presented for expedient examples, e.g., waveguides, end effectors and gratings. The residue contamination was determined as the main origin of the exhibited performance issues. Development strategies were recommended for further research, to enable additive manufacturing on chip insensitive to residual materials. In this work, the requirements for additive manufacturing on chip were illustrated and the fundamental arrangement to enable the rapid prototyping approach as well as design individualization were demonstrated. The compensation methods developed in this work facilitate upcoming research on desirable chip types that form the basis for optical and microfluidic applications.Jüngste Fortschritte in der additiven Fertigung bieten vielversprechende Möglichkeiten zur Herstellung von Strukturen auf mikro-(opto-akustischen) elektromechanischen Systemen, d.h. Chips. Dies ist aufgrund der Anpassungsfähigkeit und -geschwindigkeit der additiven Fertigung von besonderer Bedeutung für die Forschung und Entwicklung. Diese Vorteile bieten die Möglichkeit, die Herstellung von Strukturen zu individualisieren und die Rapid-Prototyping-Methode einzusetzen. Der Kombinationsansatz der additiven Fertigung auf Chipoberflächen ermöglicht bereits Forschung, insbesondere in der Photonik und Mikrofluidik. Es wurde auf akustischen Sensoren oder Mikro-Positionierungschips bisher nie angewendet. Solche Komponenten könnten von den genannten Vorteilen profitieren, insbesondere bei der Herstellung von strahlformenden Wellenleitern sowie von Gitter- und Endeffektorstrukturen. Additive Fertigung mittels Zwei-Photonen-Polymerisationslithographie stößt auf großes Interesse, da der Prozess die Fertigung von Strukturen mit minimalen Dimensionen jenseits der Beugungsgrenze ermöglicht. Ziel dieser Arbeit ist die Untersuchung von dieses Fertigungsansatzes am Beispiel eines akustischen Sensors und eines Mikro-Positionierungschips. Eine der größten Herausforderungen stellen die optischen, thermodynamischen, Adhäsions- und Ausrichtungseffekte dar, die durch diese komplexen Substrate eingebracht werden. Auf der Grundlage von optischen und thermodynamischen Modellen wurden Simulationen durchgeführt, die in einer Kompensationsmethode zur Bewältigung der Effekte kulminierten, welche durch Parameterstudien verifiziert wurde. Die Substratausrichtung wurde untersucht, was zur Entwicklung und Herstellung eines Ausrichtungs-Upgrades für das hier verwendete Fertigungssystem führte. Der Einfluss der Prozessmaterialien stellte eine weitere Herausforderung dar, da sie zu Veränderungen der Leistungsfähigkeit der Chips führten. Mit Entwicklungsmitteln und Fotolacken behandelte Chips wurden unter anderem mit optischen Hochfrequenzmikrofonen charakterisiert. Aufgrund der hohen Präzision der Kompensationsmethode und des Ausrichtungs-Upgrades, wurde erstmals die additive Fertigung mittels Zwei-Photonen-Polymerisationslithographie auf den untersuchten Bauelementen berichtet und an Wellenleitern, Endeffektoren und Gittern demonstriert. Die Kontamination durch Rückstände wurde als Hauptursache für die aufgezeigten Leistungsprobleme ermittelt. Es wurden Entwicklungsstrategien für die weitere Forschung empfohlen, um den Fertigungsansatz unempfindlich gegenüber Reststoffen zu machen. In dieser Arbeit wurden die Anforderungen an den Fertigungsansatz veranschaulicht und die grundlegende Anordnung zur Ermöglichung des Rapid-Prototyping-Ansatzes sowie der Design-Individualisierung demonstriert. Die in dieser Arbeit entwickelten Kompensationsmethoden ermöglichen die künftige Forschung an weiteren Chiptypen, die z. B. die Grundlage für optische oder mikrofluidische Anwendungen bilden
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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