Researchers have shown that by combining multiple input multiple output (MIMO) techniques with CDMA then higher gains in capacity, reliability and data transmission speed can be attained. But a major drawback of MIMO-CDMA systems is multiple access interference (MAI) which can reduce the capacity and increase the bit error rate (BER), so statistical analysis of MAI becomes a very important factor in the performance analysis of these systems. In this thesis, a detailed analysis of MAI is performed for binary phase-shift keying (BPSK) signals with random signature sequence in Raleigh fading environment and closed from expressions for the probability density function of MAI and MAI with noise are derived. Further, probability of error is derived for the maximum Likelihood receiver. These derivations are verified through simulations and are found to reinforce the theoretical results. Since the performance of MIMO suffers significantly from MAI and inter-symbol interference (ISI), equalization is needed to mitigate these effects. It is well known from the theory of constrained optimization that the learning speed of any adaptive filtering algorithm can be increased by adding a constraint to it, as in the case of the normalized least mean squared (NLMS) algorithm. Thus, in this work both linear and non-linear decision feedback (DFE) equalizers for MIMO systems with least mean square (LMS) based constrained stochastic gradient algorithm have been designed. More specifically, an LMS algorithm has been developed , which was equipped with the knowledge of number of users, spreading sequence (SS) length, additive noise variance as well as MAI with noise (new constraint) and is named MIMO-CDMA MAI with noise constrained (MNCLMS) algorithm. Convergence and tracking analysis of the proposed algorithm are carried out in the scenario of interference and noise limited systems, and simulation results are presented to compare the performance of MIMO-CDMA MNCLMS algorithm with other adaptive algorithms.

There exist some concern regarding the sustainability of the production of R&D output and R&D capacity in South Africa. Recent trends indicated evidence of disinvestments and decay of South Africa’s R&D capacity. Questions arise concerning the detrimental effects these trends could have on South Africa’s ability to generate R&D output. As problems are addressed insufficiently and the system is allowed to decay, the costs of rebuilding the system might increase even further. The main research of objective of this thesis is to develop a computer simulation program of R&D performance and the creation of R&D output in the NSI. This model will in turn produce a tool to be used for policy testing, what-if scenario testing or policy optimisation. The purpose of the model is to simulate R&D output generated in the South African system of innovation and to model and explain the effect the presence/lack of long-term investment in R&D and R&D resources could have on the system’s ability to produce R&D output. In developing this model and by using the corresponding simulation programme, decision-makers in government and industry are provided with a tool to analyse policy alternatives. The model will provide a better understanding of the interrelationships between different elements of the NSI, in particular those interacting as funders and performers of R&D. This model will also aid decision makers in enhancing the efficiency of addressing problem areas within the South African R&D system. The contribution made by this thesis to the body of knowledge is that the development of a system dynamic model will result in the establishment of a dynamic hypothesis of the development of new knowledge through R&D in an R&D performing sector. The dynamic hypothesis will in turn lead to a method for modelling the effect of R&D investment on the development of an R&D capacity, i.e. the system’s ability to absorbed knowledge and produce R&D output. The above is essentially a dynamic description of the process around creating and absorbing knowledge through R&D activities. / Thesis (PhD (Engineering Management))--University of Pretoria, 2007. / Graduate School of Technology Management (GSTM) / PhD / Unrestricted

This dissertation introduces three novel multiuser detection approaches in Multiple Input Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems by blind signal separation (BSS) techniques. The conventional methodologies for multiuser detection have to retransmit channel state information (CSI) constantly from the transmitter in MIMO ODFM systems at the cost of economic efficiency, because they require more channel resources to improve the communication quality. Compared with the traditional methodologies, the proposed BSS methods are relatively efficient approaches without the unnecessary retransmission of channel state information. The current methodologies apply the space-time coding or the spatial multiplexing to implement an MIMO OFDM system, which requires relatively complex antenna design and allocation in the transmitter. The proposed Spatial Division Multiple Access (SDMA) method enables different mobile users to share the same bandwidth simultaneously in different geographical locations, and this scheme requires only one antenna for each mobile user. Therefore, it greatly simplifies the antenna design and allocation. The goal of this dissertation is to design and implement three blind multiuser detection schemes without knowing the channel state information or the channel transfer function in the SDMA-based uplink MIMO OFDM system. The proposed scenarios include: (a) the BSS-only scheme, (b) the BSS-Minimum Mean Square Error (MMSE) scheme, and (c) the BSS-Minimum Bit Error Ratio (MBER) scheme. The major contributions of the dissertation include: (a) the three proposed schemes save the commercially expensive cost of channel resources; (b) the proposed SDMA-based uplink MIMO OFDM system simplifies the requirements of antennas for mobile users; (c) the three proposed schemes obtain high parallel computing efficiency through paralleled subcarriers; (d) the proposed BSS-MBER scheme gains the best BER performance; (e) the proposed BSS-MMSE method yields the best computational efficiency; and (f) the proposed BSS-only scenario balances the BER performance and computational complexity.

O envelhecimento promove o aparecimento de doenças crônicodegenerativas, entre elas a osteoartrose. Artroplastia Total de Quadril (ATQ) tem sido procedimento comumente frequentemente com uso de cimento ósseo metilmetacrilato (MTC). Por outro lado, importantes alterações hemodinâmicas são descritas durante o procedimento de cimentação. A raquianestesia é um procedimento anestésico que produz menores efeitos hemodinâmicos e melhor analgesia pós-operatória em comparação a anestesia geral para a ATQ. Entretanto, especificamente neste procedimento cirúrgico tais alterações permanecem a ser investigadas. Buscamos avaliar os efeitos hemodinâmicos através da técnica de cardioimpedância em pacientes idosos submetidos à cirurgia de ATQ com o uso de MTC e raquianestesia. Utilizamos um estudo transversal, observacional, comparativo, inter-metodológico e com intervenção ativa. Método: Doze pacientes de ambos os sexos, > 65 anos, com indicação ortopédica para ATQ foram estudados. Os sujeitos receberam avaliação pré-anestésica e realizaram exames laboratoriais préoperatórios. Foram submetidos à cirurgia de ATQ com utilização de raquianestesia e implante de cimento de MTC. Os pacientes foram monitorados hemodinamicamente por meio da cardiografia de impedância, da saturação de oxigênio e pressão arterial, no intra-operatório, no momento acordado, durante a indução anestésica, na colocação do MTC e após este procedimento. Após a expansão volêmica observamos que houve aumento do DC quando comparado a raquianestesia, cimentação, inserção, redução da prótese e ao final da cirurgia (P<0,05). Tais resultados foram de certa forma, atenuados na presença de efedrina. No entanto, o VS sofreu alterações nos eventos supracitados na presença ou não da droga. Por outro lado, a FC, o IC e a RVS sofreu poucas alterações durante os eventos estudados. O DC, IC e o VS se correlacionaram com a massa corporal (r = 0,81, 0,60 e 0,67 respectivamente), o VS se correlacionou negativamente com a idade (r = -0.67), o IC se correlacionou negativamente com a classe funcional pela NYHA (r = -0,61) e o DC se correlacionou positivamente com a quantidade de efedrina administrada (r = 0,70). Conclusão: O procedimento cirúrgico de ATQ com MTC sob raquianestesia produz alterações hemodinâmicas e a cardioimpedância foi um instrumento útil para guiar os procedimentos e conduta do intraoperatório, configurando-se como uma técnica interessante para monitorização não invasiva. / Aging promotes the onset of chronic diseases, including osteoarthritis. Hip arthroplasty procedure has been commonly often the use of methylmethacrylate bone cement (MMA) has been used in the surgical procedure. On the other hand, significant hemodynamic changes are described in the cementation procedure. Spinal anesthesia is an anesthetic that produces less hemodynamic effects and better postoperative analgesia compared to general anesthesia for surgery arthroplasty. However, this particular surgical procedure (hip arthroplasty) such changes remain to be investigated. To evaluate the hemodynamic effects through cardioimpedance technique in elderly patients undergoing surgery for hip arthroplasty with the use of MMA for prosthetic hip and spinal. Twelve patients of both sexes, > 65 years, with orthopedic indication for hip arthroplasty were studied. The subjects received preanesthetic evaluation and underwent preoperative laboratory. From then underwent surgery for hip arthroplasty with use of spinal anesthesia and MMA cement. Patients were haemodynamically monitored by impedance cardiography, oxygen saturation and blood pressure intraoperative, when awake, during anesthesia induction, installing the MMA cement and after this procedure. After volume expansion, we observed that there was increase in CO when compared to spinal anesthesia, cementing, insertion, and reduction of the prosthesis at surgery (P<0.05). These results were somewhat attenuated in the presence of ephedrine. However, the SV underwent changes at aforementioned event on the presence or not of drugs. On the other hand, HR, CI and SVR has a few changed during the studied event. The CO, CI and the SV was correlated with body mass (r = 0.81, 0.60 and 0.67 respectively), SV was negatively correlated with age (r = -0.67), the CI was negatively correlated with NYHA functional class (r = -0.61) and CO was positively correlated with the amount of ephedrine administered (r = 0.70).Conclusion: The surgical procedure for hip arthroplasty under spinal anesthesia with MMA produces haemodynamic changes and cardioimpedance was a useful tool to guide the procedures and conduct of the intraoperative considering as interesting technique for noninvasive monitoring.

Introduktion: CT-angiografi med kontrastinjektion kan ge en god visualisering av kroppens blodkärl. Även om CT har många fördelar i samband med avbildning, har det några nackdelar som bör uppmärksammas. Det finns forskning som visar hur optimering av kontrastmedelsanvändning kan minska stråldosen och samtidigt förbättra bildkvaliteten. Syfte: Syftet med denna studie är att undersöka hur kontrastmedelsanvändningen vid CT-angiografi kan optimeras utifrån faktorerna cardiac output, arm- och kroppspositionering samt val av injektionsplats. Material och metod: En systematisk litteraturöversikt genomfördes. Studierna som använts i litteraturstudien hämtades från tre olika databaser. Totalt valdes 16 studier ut för att besvara syftet. De inkluderade artiklarna publicerades på engelska mellan 2010–2019. Resultat: Resultatet visade att blodflödet beror på cardiac output och påverkar kontrastförstärkningen i kärlen. Den ventrala armpositionen bidrar till minst artefakter och förbättrad kontrastförstärkning. Den optimala kroppspositioneringen är den som följer blod- och kontrastflödet för att undvika artefakter. Resultatet visade även att injektion i höger arm gav bättre attenuering, mindre artefakter samt lägre stråldos. Slutsats: Resultatet från studien visade att de olika faktorerna hos patienten kan påverka kontrastförstärkningen i blodkärlen samtidigt som bildkvalitet förbättras och stråldosen reduceras.

Studiens syfte är att undersöka vilka arbetssätt lärare använder med skönlitterära texter för att utveckla det svenska språket hos andaspråkselever. I studien intervjuas fyra lärare på fyra mångkulturella skolor. Lärarna arbetar i årskurs fyra, fem och sex. Det insamlade materialet analyserades och kategoriserades utifrån gemensamma mönster som kunde hittas i intervjuerna. Den teoretiska utgångspunkten i denna studie är socialkonstruktionism. Genomgående begrepp som studien tar hänsyn till är begriplig input och begriplig output. Begriplig input innebär att läraren ger andraspråkselever möjlighet att använda sitt modersmål, bildstöd eller ämnesspecifika ord för att tolka en skönlitterär text på svenska. Begriplig output innebär att läraren ger andraspråkselever möjlighet att uttrycka sig med hjälp av svenska språket för att göra sig förstådda. Resultatet visar att lärarna använder sig av bildstöd, modersmål och ämnesspecifika ord för att göra skönlitterära texter begripliga för andraspråkselever. Vidare framgår det att en nyckelfaktor för att utveckla det svenska språket hos andraspråkselever är att ta hänsyn till deras bakgrund och förkunskaper. Lärarna använder sig både av gemensam läsning och individuell läsning av skönlitterära texter för att utveckla det svenska språket hos dessa elever.

Le pronostic à court terme des patients d'oncohématologie admis en réanimation s'est notablement amélioré au cours des deux dernières décennies. Ces progrès sont le fait d'une diversification importante de l'arsenal thérapeutique relatif à l'oncologie et l'hématologie mais aussi d'une meilleure prise en charge de ces patients au sein des réanimations. Notre travail de recherche s'est centré sur la devenir de ces malades et les facteurs associés à celui-ci.Dans ce cadre, nous avons conduit plusieurs études observationnelles pronostiques portant sur des patients neutropéniques admis en réanimation. Nous avons montré que les facteurs indépendamment associés à la mortalité hospitalière étaient une allogreffe de moelle, le recours à la ventilation mécanique invasive, le recours à l'épuration extra-rénale ainsi qu'une documentation microbiologique positive. De plus, chez les patients neutropéniques admis en réanimation pour sepsis sévère/choc septique, les facteurs indépendamment associés à la mortalité en réanimation étaient une antibiothérapie initiale inappropriée, un délai d'initiation de l'antibiothérapie en réanimation > 1h, une documentation microbiologique positive à bacille gram négatif non fermentant et à un score SOFA élevé dès l'admission en réanimation. La désescalade du traitement antibiotique initial, réalisable dans 44% des cas,était sans répercussion significative sur le pronostic à court et long-terme. Enfin, chez les patients neutropéniques admis en réanimation pour détresse respiratoire aiguë, le seul facteur indépendant associé à la mortalité hospitalière était le recours à la ventilation mécanique alors que l'utilisation de corticostéroïdes les jours précédant l'admission en réanimation et l'une admission dans un contexte de sortie d'aplasie étaient protecteurs.Finalement, nous avons montré dans une récente revue de la littérature que le pronostic du patient d'oncohématologie admis en réanimation s'était amélioré au cours du temps et que la neutropénie ne semblait pas être un facteur pronostique dans ce contexte.En conclusion, nous avons montré que le patient neutropénique est à haut risque de complications sévères infectieuses, respiratoires et immunologiques. Ces complications impactent le pronostic des patients de manière significative. Nos résultats vont donner lieu à plusieurs essais randomisés chez le patient neutropénique admis en réanimation notamment autour de la désescalade antibiotique au cours du sepsis et des stratégies d'oxygénothérapie en cas de détresse respiratoire. / The short-term prognosis of patients with onco-hematological diseases and neutropenia admitted to intensive care has significantly improved over the last two decades. This progress is the fact of a significant diversification of the armamentarium on oncology and hematology but also a better management of these patients in the ICUs. Our research has focused on the outcome of these patients and its prognostic factors. In this context, we have conducted several prognostic observational studies of neutropenic patients admitted to intensive care units. We showed that factors independently associated with hospital mortality were the bone marrow transplantation, the use of invasive mechanical ventilation, the use of renal replacement therapy and a positive microbiological documentation. Moreover, in neutropenic patients admitted to intensive care for severe sepsis / septic shock, factors independently associated with ICU mortality were inappropriate initial antibiotic therapy, a delay of antibiotic treatment > 1h, a positive microbiological documentation with non-fermenting gram negative bacilli, a high SOFA score on admission in ICU. The de-escalation of initial antibiotic treatment feasible in 44% of cases had no significant impact on the short and long-term outcomes. Otherwise, in neutropenic patients admitted to intensive care for acute respiratory failure, the only independent factor associated with hospital mortality was the need for mechanical ventilation, while the use of corticosteroids in the days before ICU admission and a admission during neutropenia recovery period were protective. Finally, we have shown in a recent review of the literature that the outcome of hematology-oncology patient admitted to intensive care had improved over time and that neutropenia did not seem to be a prognostic factor in this context. In conclusion, we have shown that the neutropenic patient is at high risk of severe infectious,respiratory and immunological complications. These complications significantly impact the outcome of these patients. Our results could lead to the planning of several randomized trials in neutropenic patients admitted to intensive care in particular about the escalation antibiotic in sepsis and oxygentherapy strategies for respiratory distress.

No description available.

The aim of the study was to compare allometrically scaled peak force and the force at 250 ms between six U.S. collegiate sport teams using isometric mid-thigh pull. Ninety subjects performed maximum effort of isometric mid-thigh pull to measure force output. The data were averaged within the teams, and statistically compared between teams using one-way ANOVA (p=.01). Significant difference was found that men’s soccer and baseball produced higher allometrically scaled peak force, and men’s soccer, tennis, and baseball produced higher allometrically scaled force at 250 ms. The data indicates that not all sports possess similar strength characteristics because of the nature of the sports, and observed separation between gender. Teams such as volleyball and baseball showed higher coefficient of variation due to the various positions within their sports.

Inflationsmålets historia sträcker sig drygt 30 år tillbaka i tiden. En förutsägbar centralbank skapar möjligheter för marknadsaktörerna att sätta upp inflationsförväntningar i linje med det uppsatta målet som bidrar till att prisstegringstakten följer den önskade nivån. I dag har en stor majoritet av de mest ekonomiskt utvecklade länderna valt att införa ett inflationsmål som ett riktmärke för landets centralbank att rikta penningpolitiken mot. Samtidigt som inflationsnivåerna har sjunkit har också stora delar av länderna idag låga räntenivåer. Det innebär att centralbankens ammunition kan vara förbrukad ifall inflationen skulle behövas tryckas upp om inflationsnivån är under sitt mål. Syftet är att försöka förklara om inflationsmålet har haft någon betydelse avseende att minska inflationsvariansen samt om det även har haft en påverkan på BNP-gapet. För att undersöka inflationsmålets betydelse har vi undersökt flera ekonomiskt välutvecklade länder från inflationsmålets introduktion fram tills nu. Relevansen och legitimiteten i studien grundas på ett flertal tidigare studier. Studien ger en historisk överblick över inflationsnivån och dess stabilitet för länderna sedan 80-talet. Resultaten visar en stadig nedgång samt stabilisering på inflationen för samtliga länder. Däremot finner vi inga stöd för att det enbart skulle vara inflationsmålets förtjänst. Vi kan inte heller observera någon skillnad för BNP-gapet med eller utan inflationsmål. Även om vi inte kan hitta bevis på skillnader av att ha ett inflationsmål eller inte, så tror vi att det har haft en betydelse för de stabiliseringar som inflationen fått tack vare att aktörer lättare kan anpassa sina förväntningar mot målet. / The inflation target's history stretches back over 30 years. A predictable central bank creates opportunities for the market participants to set inflation expectations in line with what is set to be made at the price increase that follows the desired level. Today, a large majority of the most economically well-developed countries have chosen to introduce an inflation target as a benchmark for the country's central bank to target its monetary policy. At the same time as inflation levels have fallen, large proportion of the countries today also have low interest rates. This means that the central bank's ammunition can’t be used in case a rise of inflation is needed if the level of inflation is below its target. The purpose of the thesis is to explain whether the inflation target has had any significance in reducing the inflation variance and whether it has had an impact on the output-gap. To investigate the significance of the inflation target, we have examined several economically well-developed countries from the introduction of the inflation target until now. The relevance and legitimacy of the study is based on a number of previous studies in the field of inflation targeting. The study provides a historical overview of inflation levels and stability for countries since the 1980s. The results show a steady decline and stabilization of inflation for all countries. We find no support for it being solely the merit of the inflation target. Nor can we observe any difference for the GDP gap with or without inflation targets. Although we cannot find evidence of differences in having an inflation target or not, we believe that it has had an impact on the stabilizations that inflation has gained due to the fact that actors can more easily adjust their expectations to the target.