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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Magnetic Needle Steering

January 2020 (has links)
abstract: Needle steering is an extension of manually inserted needles that allows for maneuverability within the body in order to avoid anatomical obstacles and correct for undesired placement errors. Research into needle steering predominantly exploits interaction forces between a beveled tip and the medium, controlling the direction of forces by applying rotations at the base of the needle shaft in order to steer. These systems are either manually or robotically advanced, but have not achieved clinical relevance due to a multitude of limitations including compression effects in the shaft that cause undesired tissue slicing, torsional friction forces and deflection at tissue boundaries that create control difficulties, and a physical design that inherently restricts the workspace. While most improvements into these systems attempt to innovate the needle design or create tissue models to better understand interaction forces, this paper discusses a promising alternative: magnetic needle steering. Chapter 2 discusses an electromagnetic needle steering system that overcomes all aforementioned issues with traditional steering. The electromagnetic system advances the needle entirely magnetically so it does not encounter any compression or torsion effects, it can steer across tissue-interfaces at various angles of attack (90, 45, 22.5°) with root-mean-square error (RMSE) of 1.2 mm, achieve various radii of curvature as low as 10.2 mm with RMSE of 1.4 mm, and steer along complex 3D paths with RMSE as low as 0.4 mm. Although these results do effectively prove the viability of magnetic steering, the electromagnetic system is limited by a weak magnetic field and small 33mm cubic workspace. In order to overcome these limitations, the use of permanent magnets, which can achieve magnetic forces an order of magnitude larger than similarly sized electromagnetics, is investigated. The needle will be steered toward a permanent magnet configuration that is controlled by a 6 degree-of-freedom robotic manipulator. Three magnet configurations were investigated, two novel ideas that attempt to create local maximum points that stabilize the needle relative to the configuration, and one that pulls the needle toward a single magnet. Ultimately, the last design was found to be most viable to demonstrate the effectiveness of magnetic needle steering. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020
32

Towards Security and Privacy in Networked Medical Devices and Electronic Healthcare Systems

Jellen, Isabel 01 June 2020 (has links)
E-health is a growing eld which utilizes wireless sensor networks to enable access to effective and efficient healthcare services and provide patient monitoring to enable early detection and treatment of health conditions. Due to the proliferation of e-health systems, security and privacy have become critical issues in preventing data falsification, unauthorized access to the system, or eavesdropping on sensitive health data. Furthermore, due to the intrinsic limitations of many wireless medical devices, including low power and limited computational resources, security and device performance can be difficult to balance. Therefore, many current networked medical devices operate without basic security services such as authentication, authorization, and encryption. In this work, we survey recent work on e-health security, including biometric approaches, proximity-based approaches, key management techniques, audit mechanisms, anomaly detection, external device methods, and lightweight encryption and key management protocols. We also survey the state-of-the art in e-health privacy, including techniques such as obfuscation, secret sharing, distributed data mining, authentication, access control, blockchain, anonymization, and cryptography. We then propose a comprehensive system model for e-health applications with consideration of battery capacity and computational ability of medical devices. A case study is presented to show that the proposed system model can support heterogeneous medical devices with varying power and resource constraints. The case study demonstrates that it is possible to signicantly reduce the overhead for security on power-constrained devices based on the proposed system model.
33

Medical devices in Sweden : Industrial structure, production and foreign trade 1985-2002

Sidén, Lena-Kajsa January 2003 (has links)
This licentiate thesis uses descriptive, mainly official,Swedish statistics to analyse industrial structure, productionand foreign trade in an industry that is traditionallydifficult to describe in numbers, that of medical devices. Forthe purposes of the thesis, the Swedish Medical Device industryis defined as companies classified in the SE-SIC manufacturingcodes 33101 (medical equipment and instruments, etc), 33102(dental products) and 35430 (invalid vehicles). Also otherbranches contribute, notably parts of SIC 51460 (wholesale inmedical equipment and pharmaceutical goods) and 73103 (medicalresearch and development) although their medical device volumecannot be specified. Additional items have been identified interms of specific product groups rather than as "belonging" toa specific SIC industrial code. Taken together, this is considered to correspond reasonablywell to the scope of the field as defined by the Global MedicalDevice Nomenclature (GMDN), a new European standard forclassifying medical devices in a more generic way than do theEuropean Medical Device Directives (or other pieces oflegislation). No quantification according to GMDN can be madeas yet, however, as that requires changing reporting habits inindustry as well as in official statistical classification andnomenclature regimes. With the manufacturing code SE-SIC 33101 as main object, thestudy for the first time presents data on the regionaldistribution, size classes of employment, company starting timeand company dynamics, in the form of entries to and exits fromthe code, over a six-year period. The latter analysis includesa follow-up of the "exits", some firms reappearing in otherparts of industry and others disappearing–surprisinglyfew among them being limited companies. Although this industryis comparatively mature, considerable mobility among themid-sized companies is indicated for reasons of real changes or(to some degree) factors inherent in the industrialclassification system. Some structural changes in companies inthe ≥50 employees bracket are identified. It is notedthat American actors, directly or indirectly, are increasinglyinvolved with the medical device industry in Sweden, and that anumber of technology-based companies that were started mostlyin the early eighties have recently reached the 50+ employeelevel. The analysis of identifiable production and internationaltrade in medical devices spans a period of 17 years based onofficial statistics following the HS/CN nomenclatures. Adatabase has been built, bottom-up, from the 8-digit CN levelwith production, exports and imports values for close to 100items collected in 12 product groups, for presentation purposesgrouped under three main headings. Compound annual growth ratesfor the latter are presented for three five-year periods1985-2000, showing that Swedish production and exports have hadan overall growth of 10 per cent p.a. This has kept Swedenahead of the international overall growth of 6- 7 per cent p.a.in recent years, products in the main group "Aids&Implants" growing more than 20 per cent p.a. Growth rates inthe most recent five-year period are lower, however. Healthynet exports figures are presented, the figure for 2002nominally representing 40 per cent of the production value incurrent as well as constant prices. Production figures are given at industry (local unit) levelas well as at product group level. The product-based figuresidentified for Production 2001 are estimated to SEK 13,3billion, Exports to SEK 13,7 billion and Imports to SEK 9,7billion. Figures for the Apparent Domestic Market arecalculated for the corresponding entities. It is obvious,however, that the statistics do not capture the real productionvalue as exports exceed production both at overall level and inmajor product groups, particularly those on a high systemstechnology level. The situation is not uncommon for a number ofreasons; further, cases in the statistics methodologyliterature confirm that medical instrument-related codes areliable to this phenomenon. Corrections, including adjustmentsof both production and exports values, are possible butdemanding already at one individual 4-digit HS/CN level. This,therefore, must be considered outside the scope of an academicstudy. The basic tablework developed for this thesis will be madefreely available to external parties for their own use providedthe author, with contact details, is named as the source.(Processing for commercial purposes is not expected, however.)Any suggestions for improvements are welcomed. / NR 20140805
34

Design and Manufacture of Mesoscale Robot-Actuated Surgical Instruments

Grames, Clayton L 01 November 2015 (has links) (PDF)
Minimally Invasive Surgery (MIS) is a growing field including both laparoscopic androbotic operations. Surgeons and engineers are making continual efforts to reduce the negative effects of procedures on patients. Reducing the size of the surgical instruments is one effective method pursued in this effort. When the instruments approach 3 mm in diameter, they reach a threshold where the entry incisions can be small enough that no scar is left on the patient. Laparoscopic instruments on this scale exist but typically lack wrist articulation and only have 1 degree of freedom (DoF). Alternatively, robotic surgical instruments can achieve high levels of dexterity but at a greater diameter. Smaller diameter robotic instruments employ snake wrists but this results in large swept volumes. There is a need for smaller robotic instruments with 3 DoF that preserve a small operational volume. Several unique challenges result when trying to develop small-scale instruments. Friction forces due to the relative motion of actuation cables and other parts in the mechanisms become more significant, as do the challenges of producing and assembling parts with extremely small features. These challenges have been limiting factors for the size of instruments. Traditional mechanisms use pin joints and pulleys which result in higher part counts and higher internal friction. To overcome these challenges, two alternative designs that reduce part count and minimize friction are presented as potential mechanisms that could be used as surgical instruments on the mesoscale (1-5 mm). Both designs implement rolling contact and gearing in place of pin joints and pulleys to realize their motion. Additionally, alternative manufacturing methods that are ideally suited to mesoscale production are presented. Micro metal laser sintering and composite carbon nanotude structures are shown to have the resolution required to create the detailed features necessary for these new designs. The result are two mechanisms suited to be produced as mesoscale, robotically actuated, surgical instruments. One of the two designs has been physically prototyped and has demonstrated clinical capabilities at 4 and 5 mm diameter instrument sizes.
35

Transiently Powered Computers

Ransford, Benjamin 01 May 2013 (has links)
Demand for compact, easily deployable, energy-efficient computers has driven the development of general-purpose transiently powered computers (TPCs) that lack both batteries and wired power, operating exclusively on energy harvested from their surroundings. TPCs' dependence solely on transient, harvested power offers several important design-time benefits. For example, omitting batteries saves board space and weight while obviating the need to make devices physically accessible for maintenance. However, transient power may provide an unpredictable supply of energy that makes operation difficult. A predictable energy supply is a key abstraction underlying most electronic designs. TPCs discard this abstraction in favor of opportunistic computation that takes advantage of available resources. A crucial question is how should a software-controlled computing device operate if it depends completely on external entities for power and other resources? The question poses challenges for computation, communication, storage, and other aspects of TPC design. The main idea of this work is that software techniques can make energy harvesting a practicable form of power supply for electronic devices. Its overarching goal is to facilitate the design and operation of usable TPCs. This thesis poses a set of challenges that are fundamental to TPCs, then pairs these challenges with approaches that use software techniques to address them. To address the challenge of computing steadily on harvested power, it describes Mementos, an energy-aware state-checkpointing system for TPCs. To address the dependence of opportunistic RF-harvesting TPCs on potentially untrustworthy RFID readers, it describes CCCP, a protocol and system for safely outsourcing data storage to RFID readers that may attempt to tamper with data. Additionally, it describes a simulator that facilitates experimentation with the TPC model, and a prototype computational RFID that implements the TPC model. To show that TPCs can improve existing electronic devices, this thesis describes applications of TPCs to implantable medical devices (IMDs), a challenging design space in which some battery-constrained devices completely lack protection against radio-based attacks. TPCs can provide security and privacy benefits to IMDs by, for instance, cryptographically authenticating other devices that want to communicate with the IMD before allowing the IMD to use any of its battery power. This thesis describes a simplified IMD that lacks its own radio, saving precious battery energy and therefore size. The simplified IMD instead depends on an RFID-scale TPC for all of its communication functions. TPCs are a natural area of exploration for future electronic design, given the parallel trends of energy harvesting and miniaturization. This work aims to establish and evaluate basic principles by which TPCs can operate,
36

Designing Effective Security and Privacy Schemes for Wireless Mobile Devices

Wu, Longfei January 2017 (has links)
The growing ubiquity of modern wireless and mobile electronic devices has brought our daily lives with more convenience and fun. Today's smartphones are equipped with a variety of sensors and wireless communication technologies, which can support not only the basic functions like phone call and web browsing, but also advanced functions like mobile pay, biometric security, fitness monitoring, etc. Internet-of-Things (IoT) is another category of popular wireless devices that are networked to collect and exchange data. For example, the smart appliances are increasingly deployed to serve in home and office environments, such as smart thermostat, smart bulb, and smart meter. Additionally, implantable medical devices (IMD) is the typical type of modern wireless devices that are implanted within human body for diagnostic, monitoring, and therapeutic purposes. However, these modern wireless and mobile devices are not well protected compared with traditional personal computers (PCs), due to the intrinsic limitations in computation power, battery capacity, etc. In this dissertation, we first present the security and privacy vulnerabilities we discovered. Then, we present our designs to address these issues and enhance the security of smartphones, IoT devices, and IMDs. For smartphone security, we investigate the mobile phishing attacks, mobile clickjacking attacks and mobile camera-based attacks. Phishing attacks aim to steal private information such as credentials. We propose a novel anti-phishing scheme MobiFish, which can detect both phishing webpages and phishing applications (apps). The key idea is to check the consistency between the claimed identity and the actual identity of a webpage/app. The claimed identity can be extracted from the screenshot of login user interface (UI) using the optical character recognition (OCR) technique, while the actual identity is indicated by the secondary-level domain name of the Uniform Resource Locator (URL) to which the credentials are submitted. Clickjacking attacks intend to hijack user inputs and re-route them to other UIs that are not supposed to receive them. To defend such attacks, a lightweight and independent detection service is integrated into the Android operating system. Our solution requires no user or app developer effort, and is compatible with existing commercial apps. Camera-based attacks on smartphone can secretly capture photos or videos without the phone user's knowledge. One advanced attack we discovered records the user's eye movements when entering passwords. We found that it is possible to recover simple passwords from the video containing user eye movements. Next, we propose an out-of-band two-factor authentication scheme for indoor IoT devices (e.g., smart appliances) based on the Blockchain infrastructure. Since smart home environment consists of multiple IoT devices that may share their sensed data to better serve the user, when one IoT device is being accessed, our design utilizes another device to conduct a secondary authentication over an out-of-band channel (light, acoustic, etc.), to detect if the access requestor is a malicious external device. Unlike smartphones and IoT devices, IMDs have the most limited computation and battery resources. We devise a novel smartphone-assisted access control scheme in which the patient's smartphone is used to delegate the heavy computations for authentication and authorization. The communications between the smartphone and the IMD programmer are conducted through an audio cable, which can resist the wireless eavesdropping and other active attacks. / Computer and Information Science
37

An Analysis Of Innovation And R&amp / d Activities Of Firms In Turkish Medical Devices Sector

Eren, Ilke 01 December 2010 (has links) (PDF)
This thesis aims to explore the challenges of Medical Devices sector in their innovative activities with the use of qualitative and quantitative methods. The specific subject of analysis is the Turkish Medical Device industry. Throughout the thesis the convergence of Medical Devices with pharmacy and its role in healthcare is mentioned in addition to the institutional regulations of the sector due to their effect on the firms innovative activities. The main focus of this thesis is the innovation in medical devices as vital components of healthcare supply with an important share in health expenditures. Even though Medical Devices are considered to be heterogeneous and classified in many other sectors such as chemicals, textiles and electronics, they have common features sufficient to be considered as a special product group and being an important part of the healthcare system, they are subject to common regulations. Sectoral Systems of Innovation approach is used to investigate Medical Devices Sector in Turkey. Medical devices sector also suffer from regulations that put cost on innovative activities, reimbursement policies that aim at cost containment, lower degrees of consumer support (in terms of user-producer relationship), high marketing costs due to the specific market they act in, in addition to the general obstacles such as scarce finance and human resources. Nonetheless, the ambiguity in entrance and allowance to reimbursement lists is also found to be a blocking factor on innovation.The studies on this aspect of the medical devices sector are limited and this thesis aims to fulfil the gap in this respect.
38

Evaluation clinique des dispositifs médicaux / Clinical evaluation of medical devices

Huot, Laure 20 December 2012 (has links)
Les dispositifs médicaux (DM) sont des produits de santé qui représentent un ensemblehétérogène de plus de 500 000 technologies, allant de la plus simple à la plus complexe.Contrairement au médicament, il n’existe pas de démarche formelle quant aux étapes dudéveloppement clinique des DM, notamment pour ceux les plus à risque.L’objectif de ce travail de thèse était de décrire les données cliniques disponibles en Francelorsqu’un DM accède au marché, et de proposer des solutions pour améliorer la quantité etla qualité des études cliniques réalisées. Pour cela, nous avons exploré deux voies :l’accompagnement des industriels pour la mise en place d’études cliniques qui répondentaux attentes des différents acteurs ; et l’utilisation de registres pour améliorer le niveau depreuve disponible, en générant des données cliniques complémentaires dès la diffusion.L’évaluation clinique des DM est complexe et difficile ; elle nécessite un apprentissage desindustriels et des interactions avec les autorités de santé. Toutefois, le niveau des donnéescliniques disponibles pour évaluer les DM doit et peut être amélioré, notamment par laspécialisation de méthodologistes et l’accompagnement des industriels par des plateformesproches du terrain clinique. / Medical devices are health products representing a heterogeneous set of more than 500 000technologies, from the simplest to the most complex ones. Unlike drugs, there is no formalframework for the stages of clinical development of medical devices, especially those with ahigher degree of risk.The objective of this thesis was to describe clinical data available in France when a medicaldevice is launched, and suggest some options to improve the quality and quantity of clinicalstudies performed. To this end, we explored two ways: supporting enterprises for theimplementation of clinical studies that meet the expectations of all stakeholders; and usingregistries to improve the level of available evidence by generating additional post-marketingclinical data.The clinical evaluation of medical devices is complex and difficult, and must go through thelearning of industrials and interactions with health authorities. However, the level of clinicalevidence should and can be improved, including the specialization of methodologists and theaccompaniment of enterprises through platforms close to the clinical field.
39

Le dispositif médical à la recherche d’un nouveau cadre juridique / Medical devices searching for a new legal framework

Eskenazy, Déborah 30 November 2016 (has links)
Du coeur artificiel au pansement en passant par les prothèses, lentilles correctrices, fauteuils roulants ou appareils de radiologie, la notion de dispositif médical recouvre un vaste ensemble de produits ayant en commun leur finalité médicale et leur action qui n’est pas obtenue par des moyens pharmacologiques ou immunologiques ni par métabolisme. Les dispositifs médicaux ont été règlementés dans les années 1990 par des directives fondées sur les principes de la nouvelle approche (définition d’exigences essentielles et renvoi à l’harmonisation technique, place importante laissée aux acteurs professionnels et rôle limité conféré aux autorités publiques, évaluation de la conformité des produits par des organismes notifiés et absence d’autorisation de mise sur le marché). Malgré les avantages liés à leur souplesse, ces directives n’ont qu’imparfaitement réussi à garantir la sécurité des dispositifs médicaux, ainsi que cela a été rappelé dans le contexte de l’affaire des prothèses PIP : évaluation clinique, information et traçabilité des produits insuffisantes, contrôle par et sur les organismes notifiés limité, faible coordination entre les autorités, etc. Pour renforcer la sécurité des dispositifs médicaux européens, plutôt qu’une transposition du cadre juridique des médicaments ou des dispositifs médicaux américains, un cadre juridique sur mesure, adapté à leur niveau variable de risque, est à envisager. C’est ce que proposent les règlements qui seront prochainement adoptés. / From artificial heart to bandage through implants, corrective lenses, wheelchairs or radiology devices, the concept of medical device covers a wide range of products having in common their medical purpose and their action which is not obtained by pharmacological, immunological or metabolic means. Medical devices were regulated in the 1990s by directives based on the principles of the new approach (definition of essential requirements and reference to technical harmonization, important role for professional actors and limited role for public authorities, evaluation of the conformity of products by notified bodies and absence of marketing authorization). Despite the advantages of their flexibility, these directives have only partially succeeded in guaranteeing the safety of medical devices, as underlined in the circumstances of PIP implants scandal: limited clinical evaluation, information and traceability of products, limited control by and on notified bodies, lack of coordination between authorities, etc. To strengthen the safety of European medical devices, rather than transposing the legal framework of medicinal products or American medical devices, a custom-made legal framework, adapted to their varying level of risk, is to be considered. This is what the upcoming regulations put forward.
40

Innovations in medical image processing for the design of custom medical devices and implants

Boelen, E. January 2010 (has links)
Published Article / In this article we will describe the use of 3D medical image information of individual patients as well as selected patient populations, combined with CAE tools and processes, in the rapid product development of custom and standard implantable devices. The combination of medical image information with CAE methods such as CAD, RP, FEA and CFD, allows the engineer to develop implantable devices faster and better, with optimized designs tailored to the anthropometry of the targeted patient (population), using virtual instead of mechanical prototype testing. Case studies will be demonstrated for a variety of surgical fields such as orthopaedic, cranio-maxillofacial and cardiovascular surgery.

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