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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.
1

Development of a telerobotic test bench system for small-field-of-operation bilateral applications with 3D visual and haptic (kinaesthetic) feedback

Smit, Andre 04 1900 (has links)
Thesis (MScEng) Stellenbosch University, 2014 / ENGLISH ABSTRACT: Teleoperation as a field has seen much change since its inception in the early 1940s with Dr. Raymond Goertz producing the first teleoperation system for manipulating radioactive materials. With advances in core and supporting technologies, the systems have grown in complexity and capability, allowing users to perform tasks anywhere in the world irrespective of physical distance. The feasibility of such systems has increased as the drive for use of telepresence robots, exploration robots as in space exploration, search and rescue robots and military systems such as UAVs and UGVs gain popularity. This prompted the development of a proof of concept modular, user centred telerobotic system. The current project is the second iteration in the development process. Teleoperation and more specifically telerobotic systems pose a challenge for many system developers. This may be a result of complexity or the wide assortment of knowledge areas that developers must master in order to deliver the final system. Developers have to balance system usability, user requirements, technical design and performance requirements. Several developmental process models are considered in context of Engineering Management (EM). A larger Systems Engineering developmental process is used, with focus on the primary and supportive EM components. The author used a hybrid developmental model that is user focussed in its approach, the User-Centred Systems Design (UCSD) methodology was adopted as the primary model for application within the two distinct developmental categories. The first category hardware and system integration utilised the UCSD model as is. The second - Software development - relied on the use of agile models, rapid application development (RAD) and extreme programming (XP) were discussed with XP being chosen as it could easily incorporate UCSD principles in its development process. Hardware systems development consisted of mechanical design of end-effectors, configuration management and design, as well as haptic and visual feedback systems design for the overall physical system. Also included is the physical interface design of the input (master) cell. Further software development was broken into, three sections, the first and most important was the graphical user interface, haptic control system with kinematic model and video feedback control. The force following and matching characteristics of the system were tested and were found to show an improvement over the previous implementation. The force magnitude error at steady state was reduced by 10%. While there was a dramatic improvement in system response, the rise time was reduced by a factor 10. The system did however show a decrease in angular accuracy, which was attributed to control system limitations. Further human-factor analysis experiments were conducted to test the system in two typical use-case scenarios. The first was a planar experiment and the second a 3D placement task. The factors of interest identified were field-of-view, feedback vision mode, and input modality. Heuristic performance indicators such as time-to-completion and number of collisions for a given task were measured. System performance was only showed significant improvement when used with haptic control. This shows that the research into haptic control systems will prove to be valuable in producing usable systems. The vision factor analysis failed to yield significant results, although they were useful in the qualitative systems analysis. The feedback from post-experimentation questionnaires showed that users prefer the Point of View as a field of view and 2D viewing over 3D viewing, while the haptic input modality was preferred. The results from the technical verification process can be used in conjunction with insights gained from user preference and human-factor analysis to provide guidance for future telerobotic systems development at Stellenbosch University. / AFRIKAANSE OPSOMMING: Telewerksverigting as ’n gebied het al vele veranderinge ondergaan vandat die eerste stelsels deur Dr. Raymond Goertz geimplementeer was in die vroeë 1940s vir die hantering van radioaktiewe materiale. Met vordering in kern en ondersteunende tegnologieë, het die telewerksverigtingstelsels toegeneem in kompleksiteit asook gevorder in vermoeënsvaardigheid, wat gebruikers in staat stel om take te verrig vanuit enige plek op aarde, ongeag die fisiese afstand wat die gebruiker en die werksarea skei. Die lewensvatbaarheid van hierdie stelsels het ook toegeneem weens die belangstelling in teleteenwoordigheidrobotte, ruimtevaardige-robotte, reddings-robotte en militêre-robotte soos onbemandelug- voertuie (OLV) en onbemande-grond-voertuie(OGV). As gevolg van die belangstelling in telerobotiese stelsels is die ontwikkeling van ’n modulêre, gebruikers-gesentreerde telewerksverigting stelsel onderneem. Die huidige projek is ’n tweede iterasie hiervan. Telewerksverigting, en meer spesifiek, telerobotika stelsels ontwikelling, vereis dat stelselontwikkelaars ’n verskeidenheid kennisareas bemeester. Die ontwikkelaar moet ’n belans vind tussen gebruiker vereistes, bruikbaarheid asook tegniese ontwerp en prestasie vereistes. Menigde ontwikkelingsproses modelle is oorweeg en behandel in die konteks van Ingenieursbestuur (IB). ’n Stelselsontwikkeling proses is gevolg met ’n fokus op primêre en ondersteunende IB komponente. ’n Gemengde ontwikkeling is toegepass tot die projek wat die gebruiker as ’n hoof komponent van die stelsel in ag neem. Die oorhoofse ontwikkelingsmodel is die User-centred Systems Design (UCSD) proses, wat vir beide hardeware en sagteware ontwikkeling gebruik is. Vir die hardeware ontwikkeling is die UCSD toegepas soos dit uiteengesit is in die literatuur. Die sagteware ontwikkeling is voltooi met behulp van ratse metodes, “Rapid Application Development” RAD en “Extreme Programming” (XP) was oorweeg en XP was gekies as ontwikkelingsmodel. XP was die natuurlike keuse weens die gemak waarmee UCSD metodes en prinsiepe kon geinkorporeer word in die ontwikkelings proses. Hardeware onwikkeling het bestaan uit meganiese ontwerp, manipulasiegereedskap ontwerp, konfigurasie bestuur en ontwikkeling asook haptiese en visueleterugvoer stelselsontwerp van die fisiese stelsel insluitend die fisiese koppelvlakontwerp van die meester sel. Verder is sagtewareontwerp opgedeel in ’n haptiesebeheerstel met ’n kinematiese model ontwikkeling, videoterugvoerbeheer en gebruikersintervlak ontwerp. Die vermoëe van die stelsel om krag insette na te boots was verbeter met ’n gestadigde verbetering van 10%. Die reaksietyd van die stelsel is verbeter met ’n faktor van 10. Die stelsel het ’n verswakking getoon in die algehele hoekakkuraatheid, die oorsprong van die verswakking kan aan die beheerstelsel teogeken word. Verdere menslikefaktoranalise eksperimente is voltooi om die stelsel in twee tipiese gebruikgeval scenario’s te toets. Die eerste, ’n platvlak-eksperiment en die tweede ’n 3D plasingingstaak eksperiment. Die faktore van belang is ïdentifiseer as, visie-veld, terugvoervisie modus en insette modaliteit. Heuristiese prestasie-aanwysers soos tyd-tot-voltooiing en die aantal botsings vir ’n gegewe taak is gemeet. Stelselprestasie het slegs aansienlike verbetering getoon wanneer die stelsel met die haptiesebeheer modus bedryf word. Die visiefaktor ontleding het geen noemenswaardige resultate opgelewer nie. Terugvoervorms was na elke eksperiment voltooi. Vraelyste het getoon dat gebruikers die oogpunt van ’n lae hoek en 2D video oor 3D video verkies, terwyl die haptic beheer modaliteit verkies word.
2

In pursuit of a perfect system : Balancing usability and security in computer system development

Matras, Omolara January 2015 (has links)
Our society is dependent on information and the different technologies and artifacts that gives us access to it. However, the technologies we have come to depend on in different aspects of our lives are imperfect and during the past decade, these imperfections have been the target of identity thieves, cyber criminals and malicious persons within and outside the organization. These malicious persons often target networks of organizations such as hospitals, banks and other financial organizations. Access to these networks are often gained by sidestepping security mechanisms of computer-systems connected to the organization’s network. Often, the goal of computer-systems security mechanisms is to prevent or detect threats; or recover from an eventual attack. However, despite huge investments in IT-security infrastructure and Information security, over 95% of banks, hospitals and government agencies have at least 10 malicious infections bypass existing security mechanisms and enter their network without being detected. This has resulted in the loss of valuable information and substantial sums of money from banks and other organizations across the globe. From early research in this area, it has been discovered that the reason why security mechanisms fail is because it is often used incorrectly or not used at all.  Specifically, most users find the security mechanisms on their computers too complicated and they would rather not use it. Therefore, previous research have focused on making computer-systems security usable or simplifying security technology so that they are “less complicated” for all types users, instead of designing computers that are both usable and secure. The problem with this traditional approach is that security is treated as an “add-on” to a finished computer-system design. This study is an attempt to change the traditional approach by adjusting two phases of a computer-system design model to incorporate the collection of usability as well as security requirements. Guided by the exploratory case study research design, I gained new insights into a situation that has shocked security specialists and organizational actors alike. This study resulted in the creation of a methodology for designing usable and secure computer-systems. Although this method is in its rudimentary stage, it was tested using an online questionnaire. Data from the literature study was sorted using a synthesis matrix; and analyzed using qualitative content analysis. Some prominent design and security models and methodologies discussed in this report include User-Centered System Design (UCSD), Appropriate and Effective Guidance for Information Security (AEGIS) and Octave Allegro. / Vårt samhälle är beroende av information och olika tekniker och artefakter som ger oss tillgång till den. Men tekniken vi förlitar oss på i olika aspekter av våra liv är ofullkomliga och under det senaste decenniet, har dessa brister varit föremål för identitetstjuvar, cyberbrottslingar och illvilliga personer inom och utanför organisationen. Dessa illvilliga personer riktar ofta sig till nätverk av organisationer såsom sjukhus, banker och andra finansiella organisationer. Tillgång till dessa nätverk uppnås genom att kringgå säkerhetsmekanismer av datorsystem anslutna till organisationens nätverk.   Målet med datorsystemsäkerhet är att förhindra eller upptäcka hot; eller återhämta sig från eventuella attacker. Trots stora investeringar i IT-säkerhet infrastruktur och informationssäkerhet, över 95 % av banker, sjukhus och myndigheter har minst 10 skadliga infektioner kringgå befintliga säkerhetsmekanismer och träda in i sitt nätverk utan att upptäckas. Detta har lett till förlust av värdefulla informationer och stora summor av pengar från banker och andra organisationer över hela världen. Från tidigare forskning inom detta område, har det visat sig att anledningen till att säkerhetsmekanismer misslyckas beror ofta på att den används på ett felaktigt sätt eller används inte alls. I synnerhet menar de flesta användare att säkerhetsmekanismer på sina datorer är alltför komplicerat. Därför har tidigare forskning fokuserat på att göra datorsystemsäkerhet användbar så att den är "mindre komplicerat" för alla typer av användare, i stället för att designa datorer som både är användbara och säkra. Problemet med detta traditionella synsätt är att säkerheten behandlas som ett "tillägg" till en färdig datorsystemdesign.   Denna studie är ett försök att ändra det traditionella synsättet genom att justera två faser av en datorsystemdesign modell för att integrera insamlingen av användbarhets- samt säkerhetskrav. Styrd av den explorativ fallstudie forskningsdesignen, fick jag nya insikter i en situation som har gäckat säkerhetsspecialister och organisatoriska aktörer. Denna studie resulterade i skapande av en designmetodik för användbara och säkra datorsystem. Även om denna metod är ännu i sin rudimentära fas, testades den med hjälp av en webbenkät. Data från litteraturstudien sorterades med hjälp av en syntesmatris; och analyserades med kvalitativ innehållsanalys. Några framstående design- och säkerhetsmodeller samt metoder som diskuterades i denna uppsats inkludera Användarcentrerad System Design (UCSD), Ändamålsenligt och Effektivt Vägledning för Informationssäkerhet (AEGIS) och Octave Allegro.

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