1,720,998 research outputs found
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
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Design of Enabling Technologies for Soft Minimally Invasive Surgical Robots
No full textSoft robots have rapidly evolved over the past decade due to significant advancements in sensing, actuation, control, material science, and manufacturing methods. These developments, combined with the inherent ability of soft robots to safely conform to delicate environments, have made them promising for a wide range of applications, including minimally invasive surgeries (MIS). However, to fully realize the potential of soft robots as effective systems for surgical applications, there are several remaining challenges, including: First, soft robots must be designed to meet the clinical needs of the specific target procedure, while simultaneously offering significant improvements in safety. However, the compliance offered by soft robots can also cause them to become unstable during surgical tasks that place significant loads on the robot's body. Second, highly deformable soft robots are less intuitive to control than rigid robots, complicating human-in-the-loop teleoperation for surgical applications. Finally, soft robots are generally pneumatically actuated to achieve the high forces and bandwidth needed for many surgical applications. However, this actuation method requires dedicated electromechanical components, such as pressure regulators, MOSFETs, and switches, for each actuator, making the system bulky, expensive, and limiting the robot's ability to operate untethered. This dissertation presents several new robotic systems designed to address these challenges. First we introduce the InchIGRAB, a soft robot designed for colonoscopy. The InchIGRAB sits inside a vine robot (or growing robot) and is designed to enable navigation of the entire length of the colon during both forward motion and retraction, while minimizing interaction with the delicate colon environment. We also detail the design and modeling of soft, positive-pressure actuated suction cups for anchoring flexible and continuum robots during minimally invasive surgeries. Second, to enable intuitive control of soft and continuum robots, we present Hapstick, a soft, flexible joystick that can render stiffness information to users via fiber jamming. Hapstick was demonstrated as an input interface for teleoperating a continuum robot in colorectal cancer screening tasks. Finally, we present the PneuSIC Box, a pneumatic demultiplexer that enables independent control of multiple pneumatic actuators using a single pneumatic input and a motor. We demonstrated how PneuSIC Box could be used to provide independent control of actuators in an inchworm like robot, similar to the InchIGRAB, and a soft robotic hand. Overall, this dissertation presents several new robotic systems that advance the potential of soft robots for minimally invasive surgical application
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
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Active Stiffening for Vine Robots via Axially Stacked Pneumatic Pouches
Get PDFVine robots enable safe navigation through sensitive environments due to their inherent compliance and their mechanism for growth via tip eversion. However, the compliance of these soft robots limits their ability to withstand significant loads, preventing them from performing tasks that require lifting or manipulating objects. To expand the range of applications for vine robots, they must therefore be able to increase their stiffness to prevent collapse. In this thesis, we present a low profile, active stiffening mechanism integrated into the skin of the vine robot. The mechanism consists of a set of axially stacked pneumatic pouches that generate an axial force in the robot's body to mitigate wrinkling in the robot's material, enabling the robot to withstand larger loads without collapsing. We characterized the burst pressure, stiffness, and transverse collapse load of the vine robot with our stiffening mechanism and demonstrated the ability of the robot to simultaneously stiffen and grow. Our active stiffening mechanism is implemented in an 18 mm diameter vine robot and achieves a 680\% increase in stiffness
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Development of a Low-Cost System for Laparoscopic Skills Training
Get PDFTechnological advancements in video equipment and biocompatible materials has enabled improvements in complex surgery through small incisions. The mastery of these laparoscopic surgical techniques is now a requirement for surgeons, however, the necessary skills are not intuitive and require hundreds of practice hours. The current state of surgical education includes animate models, inanimate physical models, and computer-based simulations, the latter of which are limited by cost, accessibility, and a lack of engagement. We propose a novel low-cost training interface that mimics the laparoscopic surgical environment using customized instruments whose movement and control are used as inputs for video games. The system is significantly less expensive than commercial systems and allows users freedom to select and play any game, enabling a take-home system with potential for higher levels of engagement, as well as familiarity and expertise with ambidextrous laparoscopic hand motion. A preliminary study compared performance on FLS (Fundamentals of Laparoscopic Surgery) testing before and after training. For a precision cutting task, groups that trained on a standard simulator or on the new system with either a non-inverted or inverted hand-instrument mapping, showed statistically significant improvements, warranting further investigation of training with this new system
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Design of a Portable Shape Display for Augmented Reality
Get PDFAugmented reality (AR) supplements the real environment with virtual objects, offering an immersive mode of interaction with potential for impact in a variety of applications. Recent advancements have included the ability to use ones phone as an AR display, which opens the possibility of more wide-spread adoption. Despite improvements in tracking and image processing, mobile augmented reality remains limited in its interactions, largely relying on button presses on a screen. To improve the immersiveness of AR environments and the richness of interactions, we propose a portable shape display and associated Unity App that enables users to feel the virtual objects being rendered on their phones. The device consists of a 3 x 3 array of pins, covered with a layer of soft foam to help make surfaces feel more continuous. A user study is performed to evaluate the effect of important design parameters on the degree to which interactions with various objects are perceived as realistic. Based on the results of this initial study, a final device is fabricated and tested in a second user study aimed at determining the effectiveness of the device at conveying shape information. Without visual feedback, participants correctly identified a set of four shapes with 42.86% accuracy, demonstrating the potential of the device to be used in conjunction with AR apps, including for education and design
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An End-to-End Concentric Tube Robot System Design for Medical Applications
No full textContinuum robots have significant potential for impact in surgical applications, due totheir compliance and ability to safely traverse complex and constrained environments. One class of continuum robots, known as concentric tube robots (CTRs), show particular promise for minimally invasive surgery due to their miniature size (0.5-3mm) and inherent hollow channel for the passage of surgical tools.
Despite recent advancements in CTRs, several challenges related to design, manufacturing, and teleoperation must still be addressed to achieve successful clinical translation. Due to variations in anatomy among patients and variations in task requirements among procedures, it is often necessary to customize the design of these robots on a patient- or population-specific basis. However, the complex kinematics and large design space make the design problem challenging. Here we propose a generalized computational framework that efficiently optimizes the CTR design and motion plan for safe navigation through a patient’s anatomy. The framework is the first fully gradient-based method for CTR design optimization and motion planning, enabling an efficient and scalable solution for simultaneously optimizing continuous variables, even across multiple anatomies. However, uncertainties in the manufacturing process can lead to challenges in the transition from simulated designs to physical robots. To minimize this gap, we propose an end-to-end design and manufacturing workflow on top of the previously developed optimization framework for CTRs that considers the often-overlooked impact of manufacturing uncertainty, focusing on two primary sources — tube curvature and diameter. This comprehensive approach incorporates a two-step design optimization and an uncertainty-based selection of manufacturing tolerances. By integrating these uncertainties into the design process, we can effectively bridge the gap between simulation and real-world performance, which we demonstrate through a case study on micro-laryngeal surgery. In addition to the design and fabrication of the patient-side robot, another critical aspect of minimally invasive surgical robotic systems is the surgeon-side input device for teleoperation. Delivering effective haptic feedback to the surgeon remains an open research question. Here we introduce a haptic continuum robot (HCR) for multi-modal cutaneous feedback, capable of conveying skin stretch, slip, normal indentation, and vibration to the fingertips. This device is the first to explore the use of both the tip and body of the continuum robot for haptic feedback, and it has the potential to convey task-critical information during teleoperation tasks. In summary, this dissertation aims to address the challenges in end-to-end concentric tube robot system design, enhancing both patient- and surgeon-side systems to ultimately improve clinical outcomes
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Understanding the Perception of the Twisting Sensation on the Forearm and its Application to the Design of a Soft Haptic Sleeve
No full textThe field of wearable haptics has been transitioning from the hand to the forearm, freeing the hand for various tasks in virtual and augmented reality, rehabilitation, space exploration, and teleoperation. Wearable soft devices on the forearm can be advantageous in these applications due to their form factor, comfort, and effectiveness at transmitting haptic feedback, particularly for directional guidance. One underexplored mode of haptic feedback with soft wearable sleeves is twisting the skin to generate skin stretch and a rotational cue. We aimed to understand the range of actuation angles for which twisting is perceivable on the forearm to inform the design of a soft wearable haptic sleeve. We first conducted a desktop study to examine the twisting sensation at various angles with respect to the length of the forearm, finding that users perceived twisting up to 54◦. We used this range to design a soft wearable sleeve that conveys twisting for directional guidance. We ran a second perception study with the sleeve to show the effectiveness for determining the direction and speed of the cues. Users showed approximately 80% correct identification of both directions (left and right), and > 75% correct identification of three discrete speeds (high, medium, and low). We also conducted a demonstration where users were asked to track set points using the sleeve, showing its effectiveness for guidance tasks. This work advances the design of wearable haptic interfaces by establishing how twisting cutaneous feedback can be effectively delivered and perceived, offering new opportunities for intuitive interaction in assistive and immersive technologies
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