1,720,952 research outputs found
Duurzame robotchirurgie
No full textChirurgische robotsystemen winnen aanzienlijk aan populariteit in de medische wereld vanwege hun voordelen op het gebied van precisie, comfort en behendigheid voor de chirurg, wat resulteert in een verbeterd chirurgisch resultaat. Deze voordelen gelden voor ziekenhuizen over de hele wereld, maar zijn niet overal even toegankelijk. Complexe systemen vereisen meer onderhoud, meer training voor gebruik, een aanzienlijke hoeveelheid ruimte, een grote financiële investering en ingewikkelde reinigings- en sterilisatieprocessen. Hierdoor is het integreren van deze robotsystemen toch vaak een uitdaging door de beperkte financiën en infrastructuur in kleinere ziekenhuizen. Dergelijke barricades leiden er vaak toe dat de technologie onbereikbaar wordt in omgevingen die het soms het hardste nodig hebben. De ontwikkeling van goedkope robotsystemen lijkt daarom de sleutel voor minder bedeelde ziekenhuizen om toch toegang te krijgen tot de voordelen die robotchirurgie kent
Design of a gearbox interface for robotic control of the SATA mechanism
No full textMinimally invasive robotic surgery adds benefits to the patients, such as reduced blood loss, less scaring and reduced hospital stay. From the literature research preceding this thesis, some of the major obstacles in robotic surgery are the high costs and limited reusability of the instruments. In order to have more affordable robotic surgery, there is a need for low cost robotics and easily cleanable instruments. The design project presented in this thesis represents a driver interface for robotic control of the SATA instrument and is divided into three detachable subassemblies: a motor unit, a cup interface and a gearbox with angular position feedback. This project also represents an upgrade to an existing design that contains the motors and the gearbox inside a single unit, without any sensorics. Design requirements and goals were establish at the start of the project. Possible solutions were designed in CAD and mapped into a morphological table. Each design obstacle had many possible solutions that were considered before choosing the best suited ones. Two prototypes were build out of aluminium and steel with PEEK bushings and 3D printed outer cases. The range of motion and lateral pulling force of the SATA instrument controlled by these prototypes were tested, together with the assembly-disassembly times and shaft coupling times between the gearbox and motor unit shafts. The experimental results showed very low gearbox exchange times and low coupling times with learning curves that prove the ease of use for new users, all translating into a design that allows fast instrument exchange during surgery. The design requirements were met and physical prototypes built and tested, proving the concept works and is suited for the operating room, heading towards affordable robotic surgery.Biomedical Engineerin
Design and validation of a small and light robotic arm for laparoscopic surgery
No full textMinimally invasive surgery (MIS) has developed greatly in the world of surgery in recent years. The use of robotic systems in this field has increased in the past decades. In this procedure, the surgeon requires excellent dexterity and precision. On the other hand, the patient requires safety and minimum incisions during the procedure. These have been the driving forces for the development of robotic systems for laparoscopic surgery. However, existing successful robotic systems have some common drawbacks: high cost, excessive complexity, heavy weight, and large size.In this work, we focus on the design methodology for developing a robotic arm for minimally invasive surgery that meets all the requirements of the procedure. The aim of this project is to progress towards a next generation surgical robotic arm that reduces the weight and size of the system. Based on a comprehensive study of laparoscopic surgery, the design goals and requirements were defined. The design is based on a novel division of the surgery into two sub-operations: a global passive positioning and a local active laparoscopic motion. This permits to reduce the overall size of the robotic arm and to develop specific functional mechanisms. The first mechanism allows the alignment of the incision point with the centre of rotation. It is light and intuitive to set up. The second mechanism is responsible for the active surgical movement and is inspired by the spherical linkage.A complete kinematic analysis and optimization is performed to optimize the geometrical parameters of the mechanisms. The optimization is defined as a multifunctional optimization problem with the aggregation of objective functions, that increase compactness, reduce size, and avoid singularities. In addition, a workspace validation is presented. Motors, sensors, materials, and cross-sectional areas of all parts are selected and tested so that all requirements are satisfied.Finally, a first prototype of the alignment mechanism is built and an experiment is conducted to prove the ease of setting up the robotic arm. The results demonstrate the ease of setting up the system and the simplicity of the steps for alignment. It also shows that the alignment mechanism is intuitive to use without extensive training.The proposed robotic arm is suitable for appendectomy, cholecystectomy, and inguinal hernia surgery and has several advantages: It is smaller and lighter than commercially available robotic arms, weighting less than 3 kg and measuring 318 mm x 241.4 mm x 35 mm and 385 mm x 178 mm x 101 mm, and it is portable, as specified in the European standards. This modular design with a division into an alignment mechanism and a surgical mechanism has reduced the size of the overall system and its complexity.Mechanical Engineering | BioMechanical Desig
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
SATA-LRS: A modular and novel steerable hand-held laparoscopic instrument platform for low-resource settings<sup>☆</sup>
No full textBackground: Hospitals in low resource settings (LRS) can benefit from modern laparoscopic methodologies. However, cleaning, maintenance and costs requirements play a stronger role while training and technology are less available. Steerable laparoscopic instruments have additional requirements in these settings and need extra identified adaptations in their design. Method: Several modular detachability and tip steerability features were applied to the SATA-LRS instrument platform designed specifically for LRS. Ten subjects participated a dis- and reassembly experiment to validate the modularity, and in a steering experiment using a custom made set-up to validate steering. Results: A new steerable SATA-LRS instrument was developed with the ability to exchange end-effectors through a disassembly of the shafts. Experiments showed an average 34 and 90 s for complete dis- and reassembly, respectively. Participants were able to handle the instrument independently after a single demonstration and 4 rounds of repetitions. Precise tip-target alignment in the box set-up showed a very short learning-curve of 6 repetitions. Conclusion: A novel instrument platform with articulating and rotating end-effector was designed for LRS. Within a minute the SATA-LRS can be disassembled to component level for inspection, cleaning, maintenance and repair, and can be autonomously reassembled by novices after a minimal training. The modular buildup is expected to reduce purchasing and repair costs. The instrument has been shown intuitive by use without extensive training.Medical Instruments & Bio-Inspired Technolog
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
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