Multicore processors often increase the performance of applications. However, with their deeper pipelining, they have proven increasingly difficult to improve. In an attempt to deliver enhanced performance at lower power requirements, semiconductor microprocessor manufacturers have progressively utilised chip-multicore processors. Existing research has utilised a very common technique known as thread-level speculation. This technique attempts to compute results before the actual result is known. However, thread-level speculation impacts operation latency, circuit timing, confounds data cache behaviour and code generation in the compiler. We describe an software framework codenamed Lyuba that handles low-level data hazards and automatically recovers the application from data hazards without programmer and speculation intervention for an asymmetric chip-multicore processor. The problem of determining correct execution of multiple threads when data hazards occur on conventional symmetrical chip-multicore processors is a significant and on-going challenge. However, there has been very little focus on the use of asymmetrical (heterogeneous) processors with applications that have complex data dependencies. The purpose of this thesis is to: (i) define the development of a software framework for an asymmetric (heterogeneous) chip-multicore processor; (ii) present an optimal software control of hardware for distributed processing and recovery from violations;(iii) provides performance results of five applications using three datasets. Applications with a small dataset showed an improvement of 17% and a larger dataset showed an improvement of 16% giving overall 11% improvement in performance.

Thesis (MComm)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Tsetse flies (Glossina spp), native to mid-continental Africa, are the vectors of trypanosomes that causes human (sleeping sickness) and animal (nagana) trypanosomiasis. Vector control plays a major role in alleviating the burden of the disease. Mathematical models of tsetse population dynamics provide insights into how best to manage these control efforts. A major mark-recapture experiment, carried out in Zimbabwe, provided valuable information on tsetse population dynamics, but the analyses so far published could be improved on because not all of the information available on the marking procedure was used. We have constructed an individual-based model that follows the life of individual tsetse flies, their progeny and, in particular, the sequence of occasions on which individual flies were captured and given distinctive marks. We have access to comprehensive data from the tsetse fly mark-release-recapture experiment carried out on Antelope Island, Lake Kariba, Zimbabwe. In order to calibrate or validate the model, we model both the growth of the introduced tsetse population and the mark-recapture process. We have compared the model outputs to the original data and recommend processes that may be followed for model calibration. It is possible to construct an individual-based model that adequately models tsetse fly populations. Whereas the focus of this study has been on modelling the mark-recapture study, the individual-based model could also be used in more general settings to model the growth, and reduction in fly numbers, changes in age structure, species and gender ratios and the acquisition of trypanosome infections by individual flies. This model can thus be used to investigate the effect of various factors on tsetse fly and trypanosome, population dynamics as well as on the performance of various control techniques effecting fly mortality and disease transmission. / AFRIKAANSE OPSOMMING: Tsetsevlieë (Glossina spp), inheems aan sentraalkontinentale Afrika, is die draers van trypanosomen wat trypanosomiasis by die mens (slaapsiekte) en by diere (nagana) veroorsaak. Die beheer van draers speel 'n belangrike rol om die las wat die siekte veroorsaak, te verlig. Wiskundige modelle van tsetse bevolkingsdinamika bied insigte oor hoe om beheerpogings die beste te bestuur. 'n Belangrike merk-hervang eksperiment, wat in Zimbabwe uitgevoer is, bevat waardevolle inligting oor tsetse bevolkingsdinamika. Die ontleding daarvan, wat tot dusver gepubliseer is, kan egter verbeter word aangesien nie al die inligting beskikbaar in die merkprosedure, gebruik is nie. Ons het 'n individu-gebaseerde model saamgestel wat die lewens van individuele tsetsevlieë en hul nageslagte volg, in besonder die volgorde waarop individuele vlieë gevang en herkenbaar gemerk is. Ons het toegang tot omvattende data van die tsetsevlieg merk-vrylaat-hervang eksperiment wat uitgevoer is op Antelope Eiland, Karibadam, Zimbabwe. Ten einde die model te kalibreer of om die model se geldigheid te bevestig, modelleer ons beide die groei van die ingevoerde tsetse bevolking en die merk-hervangs metode. Ons vergelyk die modeluitsette met die oorspronklike data en beveel prosesse aan wat gevolg kan word om die model te kalibreer. Dit is moontlik om 'n individu-gebaseerde model saam te stel wat tsetsevliegbevolkings voldoende moduleer. Terwyl hierdie studie die modellering van die merk-hervang data bestudeer, kan die individueel-gebaseerde model ook gebruik word in meer algemene gevalle vir die modellering van die vermeerdering en vermindering in vlieë getalle, veranderinge in die ouderdomstruktuur, spesies en geslagverhoudings en die verwerwing van trypanosomen infeksies deur individuele vlieë. Hierdie model kan dus gebruik word om die effek te ondesoek van verskeie faktore op die tsetsevlieg en trypanosomen, populasiedinamiek sowel as die prestasie van verskillende beheertegnieke rakende vliegsterftes en siekte-oordrag.

On April 7, 2009, IBM celebrated the mainframe’s 45th year. Drawing on its roots in punch-card tabulators, the machine has come a long way to become many customers’ preferred e-business solution. Throughout its lifetime, IBM’s strategy adapted the machine to the changing market. During the late 1960s, the introduction of the System/360 provided customers with compatibility and scalability across various computer lines. Popularity of the system began to suffer during the client/server era of the 1990s but it quickly recovered as the z Series server line was developed to support e-business solutions. IBM’s strategy made the mainframe successful but continued improvements are still necessary to ensure its future success. / text

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Detta arbete behandlar ett företags möjligheter att bidra till ett mer hållbart samhälle. Syftet är att undersöka hur ett företag, IBM Svenska AB, kan bidra till ett mer hållbart samhälle genom att verka för hållbara transportalternativ. För att söka resultat har insamling av material främst skett genom intervjuer med ansvarig för samhällsansvar och externa relationer vid IBM Svenska AB samt grundaren av CERO-modellen, en modell som hjälper företag att nå uppsatta klimatmål inom organisationen. Litteratur som använts har främst varit inom områdena: företagsansvar, Mobility Management och individers handlande för att försöka få en helhetsbild gällande vad som gör att hållbara alternativ implementeras eller inte. Slutsatserna var att företag, i stor utsträckning, har möjlighet att påverka arbetstagare och samhället i stort för att bidra till ett mer hållbart samhälle. Dock framkom svårigheter med att se om de uppsatta målen inom verksamheten verkligen uppfylls eftersom arbetstagare, enligt teorier, ofta utför handlingar efter eget tycke och smak.

The focus of this case lies in the post-merger integration issues that Lenovo had to master in order to extract full value as well as synergies from its acquisition. The time span analyzed is from the merger until approximately one year after. The case describes the "Best of Both Worlds" integration approach adopted by Lenovo and the top management team's attempts to set aside egos and learn from each other, as well as to make decisions that are in the best interest of the new company, e.g., the decision to move the corporate headquarters to the US and to use English as the working language. The case illustrates the significant cultural differences separating the two companies and draws attention to the first major difficulties starting only eight month after the merger when the new CEO, Steve Ward, was replaced by Bill Amelio, an ex-Dell executive. This raised questions as to whether Lenovo was able to build a diverse top management team that could successfully run a global business. (author's abstract) / Series: WU Case Series