Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 51-53). / This thesis documents the design and implementation of a game controller glove that employs optical tracking technology to detect movement of the hand and fingers. The vision algorithm captures an image from a webcam in real-time and determines the centroids of colored sections on a glove worn by the player; assigning a distinctive identifier for each section which is associated with a 3D model retrieved from a preexisting library. A Vivitouch artificial muscle module is also mounted to the top of the glove to provide vibratory haptic feedback to the user. The system has been user tested and a number of potential use scenarios have been conceived for integration of the controller in various gaming applications. / by Samantha N. Powers and Lauren K. Gust. / S.B.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 89-92). / Quorum sensing is a decentralized biological process, by which a community of bacterial cells with no global awareness can coordinate their functional behaviors based only on local decision and cell-medium interaction. This thesis draws inspiration from quorum sensing to study the data clustering problem, in both the time-invariant and the time-varying cases. Borrowing ideas from both adaptive estimation and control, and modern machine learning, we propose an algorithm to estimate an "influence radius" for each cell that represents a single data, which is similar to a kernel tuning process in classical machine learning. Then we utilize the knowledge of local connectivity and neighborhood to cluster data into multiple colonies simultaneously. The entire process consists of two steps: first, the algorithm spots sparsely distributed "core cells" and determines for each cell its influence radius; then, associated "influence molecules" are secreted from the core cells and diffuse into the whole environment. The density distribution in the environment eventually determines the colony associated with each cell. We integrate the two steps into a dynamic process, which gives the algorithm flexibility for problems with time-varying data, such as dynamic grouping of swarms of robots. Finally, we demonstrate the algorithm on several applications, including benchmarks dataset testing, alleles information matching, and dynamic system grouping and identication. We hope our algorithm can shed light on the idea that biological inspiration can help design computational algorithms, as it provides a natural bond bridging adaptive estimation and control with modern machine learning. / by Feng Tan. / S.M.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 29). / Chaotic mixing of highly viscous fluids is common in many biological and industrial processes. This study aims to gain insight about the properties of such common processes by examining one particular case of viscous, chaotic mixing: the rotor-oscillator flow. For some couplings of the rotor motion with its oscillation, this flow has been shown to have coherent islands of fluid parcels surrounded by a sea of chaos. Through finite-time Lyapunov exponent (FTLE) analysis, a roughly optimal coupling was found. The parameters that describe this coupling are the nondimensional oscillation amplitude [epsilon] = 0.125 and frequency [lambda] = 0.4[pi]. In order to understand more about the mixing of slow-moving, highly viscous fluids, these values can and will be explored experimentally and through braid theory to further examine the regions of coherence in this generally chaotic flow. / by Sarah Fay. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996. / Includes bibliographical references (leaves 170-177). / by Aravind Padmanabhan. / Ph.D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 73-76). / In this thesis, a framework is developed to investigate the effect of resource sharing on the performance of genetic networks. A model of a genetic system with shared resources for protein degradation is developed that captures resource sharing effects and is subsequently analyzed to discover ways in which this form of resource sharing effects genetic networks. It is shown that sharing of degradation resources may cancel undesirable effects due to resource sharing of protein production resources. Next, a theoretical framework is developed to find conditions in which a genetic network may exhibit a change in its number of equilibria due to resource sharing effects. Finally, metrics and an experimental method are proposed to estimate the quantity of resources a genetic network uses and the sensitivity of the network to disturbances in resource availability. These measures may be utilized to inform design choices in genetic networks in which resource sharing plays a significant role. These effects become increasingly important in more complex genetic networks. Quantification of such resource sharing effects are an important step in increasing the predictability of genetic networks. / by Cameron D. McBride. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1993. / Includes bibliographical references (leaves 141-147). / by Sungdo Ha. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (leaves 122-127). / For more than 2,500 years, surgical teaching has been based on the so called "see one, do one, teach one" paradigm, in which the surgical trainee learns by operating on patients under close supervision of peers and superiors. However, higher demands on the quality of patient care and rising malpractice costs have made it increasingly risky to train on patients. Minimally invasive surgery, in particular, has made it more difficult for an instructor to demonstrate the required manual skills. It has been recognized that, similar to flight simulators for pilots, virtual reality (VR) based surgical simulators promise a safer and more comprehensive way to train manual skills of medical personnel in general and surgeons in particular. One of the major challenges in the development of VR-based surgical trainers is the real-time and realistic simulation of interactions between surgical instruments and biological tissues. It involves multi-disciplinary research areas including soft tissue mechanical behavior, tool-tissue contact mechanics, computer haptics, computer graphics and robotics integrated into VR-based training systems. The research described in this thesis addresses many of the problems of simulating tool-tissue interactions in medical virtual environments. First, two kinds of physically based real time soft tissue models - the local deformation and the hybrid deformation model - were developed to compute interaction forces and visual deformation fields that provide real-time feed back to the user. Second, a system to measure in vivo mechanical properties of soft tissues was designed, and eleven sets of animal experiments were performed to measure in vivo and in vitro biomechanical properties of porcine intra-abdominal organs. Viscoelastic tissue / (cont.) parameters were then extracted by matching finite element model predictions with the empirical data. Finally, the tissue parameters were combined with geometric organ models segmented from the Visible Human Dataset and integrated into a minimally invasive surgical simulation system consisting of haptic interface devices inside a mannequin and a graphic display. This system was used to demonstrate deformation and cutting of the esophagus, where the user can haptically interact with the virtual soft tissues and see the corresponding organ deformation on the visual display at the same time. / by Jung Kim. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006. / Includes bibliographical references (p. [116]-[127]). / This thesis reports an integrated optical wavelength specific switching device for applications in optical integrated circuits (OICs) based on micro electromechanical systems (MEMS). The device consists of a ring resonator add-drop filter and a conductive MEMS bridge which is actuated by electrostatic force. Introducing conductive material into the electromagnetic evanescent field of the ring waveguide results in loss in the propagating light within, disabling the resonance and the filtering capabilities of the ring resonator. Therefore, by actuating the MEMS bridge in and out of the waveguide's evanescent field, the filter can be toggled between the on and off states. One large problem that must be faced when fabricating and actuating a MEMS cantilever or bridge structure for this type of device is the residual stress that may deflect the structure in an undesired way. This is because the vertical displacement of the structure is crucial. In order to solve this problem, this thesis is based on the use of titanium nitride (TiN) as structural material for the bridge. Titanium nitride has very attractive mechanical properties as well as good conductivity, which makes it an ideal structural material for electrostatically actuated devices. / (cont.) Moreover, the residual stress within the material can be relieved by proper control of deposition conditions and/or post processing. This thesis focuses on the post process annealing of titanium nitride in order to eliminate the residual stress in the structure and obtain a fiat bridge profile. Titanium nitride MEMS bridge structures were fabricated and tested. Their deflection from a flat state and stress was measured and characterized, and a structure with minimal residual stress was successfully fabricated. The actuation of the MEMS bridge is also demonstrated, and its characteristics are analyzed. Also discussed is the possibility of extending the design of the MEMS switch to implement the three-electrode ultra-fast strain-induced switching and MEMS wavelength tuning of an integrated optical filter. A realistic design of these devices is proposed in context with the requirements imposed by the optical telecommunication industry, and fabrication methods are considered. Simulations have been conducted using finite element analysis and mode solving to establish the feasibility of these designs. / y Satoshi Takahashi. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995. / Includes bibliographical references (leaves 51-54). / by Manish Kothari. / M.S.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007. / Includes bibliographical references (p. 58). / Many manufacturing firms have improved their operations by implementing a work-in-process (WIP) limiting control strategy. This project explores the application of this concept to limit WIP and reduce cycle time for the Becton, Dickinson and Company's manufacturing facility in Tuas, Singapore. BD's Eclipse Safety Needle production line is facing increasing pressure to reduce its high WIP and long cycle times. With the forecast of increasing demand, the current production control practice will sooner or later push the shop floor space to a limit. We divided the overall system into three manageable sub-systems and analyzed different strategies for each. At Needle Assembly machine (AN) and downstream, we can achieve significant reduction in cycle time and work in process by eliminating the unnecessary early start of production and extra delay caused by the current planning method, and by reducing the transfer batch sizes. In this paper, we refine further these approaches to AN and packaging machines with consideration of a mixed dispatching rule and a CONWIP release rule. The mixed dispatching rule reduces WIP level of the system by enhancing the total throughput of the four production routes after the bottleneck (AN machine). The CONWIP release rule further reduces WIP by controlling the total amount of inventory in the system. With these four proposed strategies, we can have a pure pull system within AN and downstream machines and achieve significant reduction in cycle time and WIP. / by Kai Meng. / M.Eng.