With the current trend in cloud computing and virtualization, more organizations are moving their systems from a physical host to a virtual server. Although this can significantly reduce hardware, power, and administration costs, it can increase the cost of analyzing performance problems. With virtualization, there is an initial performance overhead, and as more virtual machines are added to a physical host the interference increases between various guest machines. When this interference occurs, a virtualized guest application may not perform as expected. There is little or no information to the virtual OS about the interference, and the current performance tools in the guest are unable to show this interference. We examine the interference that has been shown in previous research, and relate that to existing tools and research in root cause analysis. We show that in virtualization there are additional layers which need to be analyzed, and design a framework to determine if degradation is occurring from an external virtualization layer. Additionally, we build a virtualization test suite with Xen and PostgreSQL and run multiple tests to create I/O interference. We show that our method can distinguish between a problem caused by interference from external systems and a problem from within the virtual guest.

Thesis (MPhil)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: In the last decade, the use of computers has proliferated the industrial arena in South Africa. Due to frequent changes in computer programs and developments in the computing field, users have often been adversely affected. Users experience problems with computer programs that are not user friendly. Usability is about satisfying the user needs by allowing the user to accomplish their goals quickly, efficiently and easily. Thus it is crucial that industries invest in computer programs that offer optimum usability. In this research an attempt is made to provide a framework for methodology that can be used to test and evaluate usability in the Transwerk Risk Management Information System, that is Computer Assisted Risk Management Systems (CARMS). I first consider the difference between unusable and usable programs. Usability properties are then identified including properties enhancing effectiveness, efficiency, flexibility, laemability and attitude of the computer program. The CARMS components or modules and users were identified. Usability problems were identified that cause the users to be selective and discouraged to use other components of CARMS. To further verified and address the usability problems identified, the whole program needs to be tested and evaluated. The methodology was laid for how to do usability testing and evaluation in computer program that are currently in use like CARMS. Benefits and limitations of testing and evaluating usability were detailed in this research. It is recommended that, testing and evaluating usability should be done to prevent errors, dissatisfaction and to improve usability of the CARMS program. / AFRIKAANSE OPSOMMING: In die laaste dekade het die gebruik van rekenaars uitgebrei in die industriele arena in Suid-Afrika. Weens gereelde veranderings in rekenaar programme en ontwikkellings in die informatika veld is gebruikers gereeld nadelig geraak. Gebruikers ervaar probleme met rekenaar programme wat nie gebruikersvriendelik is nie. Bruikbaarheid het te make met bevrediging van gebruikersbehoeftes deur hulle in staat te stel om hulle doelwitte vinnig, doelmatig en maklik te bereik. Dit is dus van kritiese belang dat industriee investeer in rekenaar programme wat optimale bruikbaarheid bied. In hierdie navorsing word gepoog om 'n raamwerk vir metodologie wat gebruik kan word om die bruikbaarheid van die "Transwerk Risk Management Information System" (dit is "Computer Assisted Risk Management Systems" of CARMS) te toets en te evalueer. Ek bespreek eerstens die verskil tussen onbruikbare en bruikbare programme. Bruikbaarheidseienskappe word dan geidentifiseer, insluitend eienskappe wat doeltreffendheid, doelmatigheid, buigsaamheid, aanleerbaarheid en houding van die rekenaar program verbeter. Die CARMS komponente of modules en gebruikers is geidentifiseer. Bruikbaarheidsprobleme is geidentifiseer wat veroorsaak dat gebruikers selektief raak en ontmoedig raak om ander komponente van CARMS te gebruik. Om verder die geidentifiseerde bruikbaarheidsprobleme te verifieer en adreseer moet die hele program getoets en evalueer word. Die metodologie is vasgele waarvolgens bruikbaarheidstoetsing en evaluasie van rekenaar programme wat tans in gebruik is (soos CARMS) gedoen kan word. Voordele en beperkings van bruikbaarheidstoetsing en -evaluasie is in hierdie navorsing vervat. Dit word aanbeveel dat bruikbaarheidstoetsing en -evaluasie gedoen moet word om foute en ontevredenheid te voorkom en om die bruikbaarheid van die CARMS program te verbeter.

Thesis (MPhil (Information Science))--University of Stellenbosch, 2006. / The Human Sciences Research Council (HSRC) is South Africa’s statutory research agency dedicated to the social sciences. Information Services (IS) plays a significant role in advancing social science research through the provision of its proactive desk research and its library service. HSRC IS is looking at implementing a library solution that will better serve its users. The existing library system no longer meets the needs of the HSRC Library staff or the research staff. The functionality and efficiency of an ILS is critical to the smooth operation of IS in fulfilling its mandate within the HSRC, i.e. to provide access to information, in an efficient, useful, and timely manner, the focus being on ease of accessibility to a whole range of library and other online resources. The ILS must be able to handle many formats, accommodate searching on the Internet, provide a variety of functions including manipulating electronic data, working with graphics and expediting resource sharing. IS identified the following three ILS solutions, together with their add-on components 1) Innovative Interfaces’ Millennium solution, 2) SIRSI’s Unicorn solution and 3) Ex Libris’s ALEPH solution. The user and system requirements for ILS at the HSRC are sketched. The unique requirements, as well as the requirements the HSRC shares with other research organisations, are pointed out. The three ILS are evaluated against the criteria established. All three the ILS suppliers specialise exclusively in library automation software and have many years of experience in the provision and support of ILS, Innovative Interfaces Inc and Ex Libris for 25 years each and SIRSI for 15 years. Innovative Interfaces Inc has the largest customer base in South Africa. Ex Libris has one academic consortium as a client (CALICO) and some smaller utilisers, while SIRSI is just breaking into the South African market. All three systems comply fully with all the Cataloguing, Serials and Acquisitions modules requirements, that is, the more traditional library functionalities. When it comes to the more ‘non-traditional’ functionalities, such as full-text searching and discussion forum functionality, these systems still fall short. It is either not supported at all, or additional modules or add-ons are required. The various systems requirements are aligned to the current information technology environment at the HSRC. The conclusion is that the actual differences between the systems are few and far between, but that there are some specific requirements and add-on possibilities which makes Millennium the most attractive choice.

Indiana University-Purdue University Indianapolis (IUPUI) / Our connections to the digital world are invoked by brands, but the intersection of branding and interaction design is still an under-investigated area. Particularly, current websites are designed not only to support essential user tasks, but also to communicate an institution's intended brand values and traits. What we do not yet know, however, is which design factors affect which aspect of a brand. To demystify this issue, three sub-projects were conducted. The first project developed a systematic approach for evaluating the branding effectiveness of content-intensive websites (BREW). BREW gauges users' brand perceptions on four well-known branding constructs: brand as product, brand as organization, user image, and brand as person. It also provides rich guidelines for eBranding researchers in regard to planning and executing a user study and making improvement recommendations based on the study results. The second project offered a standardized perceived usability questionnaire entitled DEEP (design-oriented evaluation of perceived web usability). DEEP captures the perceived website usability on five design-oriented dimensions: content, information architecture, navigation, layout consistency, and visual guidance. While existing questionnaires assess more holistic concepts, such as ease-of-use and learnability, DEEP can more transparently reveal where the problem actually lies. Moreover, DEEP suggests that the two most critical and reliable usability dimensions are interface consistency and visual guidance. Capitalizing on the BREW approach and the findings from DEEP, a controlled experiment (N=261) was conducted by manipulating interface consistency and visual guidance of an anonymized university website to see how these variables may affect the university's image. Unexpectedly, consistency did not significantly predict brand image, while the effect of visual guidance on brand perception showed a remarkable gender difference. When visual guidance was significantly worsened, females became much less satisfied with the university in terms of brand as product (e.g., teaching and research quality) and user image (e.g., students' characteristics). In contrast, males' perceptions of the university's brand image stayed the same in most circumstances. The reason for this gender difference was revealed through a further path analysis and a follow-up interview, which inspired new research directions to unpack even more the nexus between branding and interaction design.