Viterbi Decoded Linear Block Codes for Narrowband and Wideband Wireless Communication Over Mobile Fading Channels

Since the frantic race towards the Shannon bound [1] commenced in the early 1950’s, linear block codes have become integral components of most digital communication systems. Both binary and non-binary linear block codes have proven themselves as formidable adversaries against the impediments presented by wireless communication channels. However, prior to the landmark 1974 paper [2] by Bahl et al. on the optimal Maximum a-Posteriori Probability (MAP) trellis decoding of linear block codes, practical linear block code decoding schemes were not only based on suboptimal hard decision algorithms, but also code-specific in most instances. In 1978 Wolf expedited the work of Bahl et al. by demonstrating the applicability of a block-wise Viterbi Algorithm (VA) to Bahl-Cocke-Jelinek-Raviv (BCJR) trellis structures as a generic optimal soft decision Maximum-Likelihood (ML) trellis decoding solution for linear block codes [3]. This study, largely motivated by code implementers’ ongoing search for generic linear block code decoding algorithms, builds on the foundations established by Bahl, Wolf and other contributing researchers by thoroughly evaluating the VA decoding of popular binary and non-binary linear block codes on realistic narrowband and wideband digital communication platforms in lifelike mobile environments. Ideally, generic linear block code decoding algorithms must not only be modest in terms of computational complexity, but they must also be channel aware. Such universal algorithms will undoubtedly be integrated into most channel coding subsystems that adapt to changing mobile channel conditions, such as the adaptive channel coding schemes of current Enhanced Data Rates for GSM Evolution (EDGE), 3rd Generation (3G) and Beyond 3G (B3G) systems, as well as future 4th Generation (4G) systems. In this study classic BCJR linear block code trellis construction is annotated and applied to contemporary binary and non-binary linear block codes. Since BCJR trellis structures are inherently sizable and intricate, rudimentary trellis complexity calculation and reduction algorithms are also presented and demonstrated. The block-wise VA for BCJR trellis structures, initially introduced by Wolf in [3], is revisited and improved to incorporate Channel State Information (CSI) during its ML decoding efforts. In order to accurately appraise the Bit-Error-Rate (BER) performances of VA decoded linear block codes in authentic wireless communication environments, Additive White Gaussian Noise (AWGN), flat fading and multi-user multipath fading simulation platforms were constructed. Included in this task was the development of baseband complex flat and multipath fading channel simulator models, capable of reproducing the physical attributes of realistic mobile fading channels. Furthermore, a complex Quadrature Phase Shift Keying (QPSK) system were employed as the narrowband communication link of choice for the AWGN and flat fading channel performance evaluation platforms. The versatile B3G multi-user multipath fading simulation platform, however, was constructed using a wideband RAKE receiver-based complex Direct Sequence Spread Spectrum Multiple Access (DS/SSMA) communication system that supports unfiltered and filtered Complex Spreading Sequences (CSS). This wideband platform is not only capable of analysing the influence of frequency selective fading on the BER performances of VA decoded linear block codes, but also the influence of the Multi-User Interference (MUI) created by other users active in the Code Division Multiple Access (CDMA) system. CSS families considered during this study include Zadoff-Chu (ZC) [4, 5], Quadriphase (QPH) [6], Double Sideband (DSB) Constant Envelope Linearly Interpolated Root-of- Unity (CE-LI-RU) filtered Generalised Chirp-like (GCL) [4, 7-9] and Analytical Bandlimited Complex (ABC) [7, 10] sequences. Numerous simulated BER performance curves, obtained using the AWGN, flat fading and multi-user multipath fading channel performance evaluation platforms, are presented in this study for various important binary and non-binary linear block code classes, all decoded using the VA. Binary linear block codes examined include Hamming and Bose-Chaudhuri-Hocquenghem (BCH) codes, whereas popular burst error correcting non-binary Reed-Solomon (RS) codes receive special attention. Furthermore, a simple cyclic binary linear block code is used to validate the viability of employing the reduced trellis structures produced by the proposed trellis complexity reduction algorithm. The simulated BER performance results shed light on the error correction capabilities of these VA decoded linear block codes when influenced by detrimental channel effects, including AWGN, Doppler spreading, diminished Line-of-Sight (LOS) signal strength, multipath propagation and MUI. It also investigates the impact of other pertinent communication system configuration alternatives, including channel interleaving, code puncturing, the quality of the CSI available during VA decoding, RAKE diversity combining approaches and CSS correlation characteristics. From these simulated results it can not only be gathered that the VA is an effective generic optimal soft input ML decoder for both binary and non-binary linear block codes, but also that the inclusion of CSI during VA metric calculations can fortify the BER performances of such codes beyond that attainable by classic ML decoding algorithms.Dissertation (MEng(Electronic))--University of Pretoria, 2006.Electrical, Electronic and Computer Engineeringunrestricte

The impact of intellectual property rights from publicly financed research and development on governance mode decisions for research alliances

This study consisted of two distinct research phases, performed within the context of the South African Council for Science and Industrial Research (and its current and potential research alliances). The purpose of the study was to develop a decision making model that would enable strategists at publicly financed research and development organisations to analyse and predict governance mode decisions, as well as select optimal governance mode structures (ranging from quasi-market structures, such as once-off contracts, to quasi-hierarchy structures, such as research joint ventures) for research alliances. During the qualitative first phase, the study aimed to identify impact domains within South Africa’s new Bayh-Dole-like Intellectual Property Rights legislative framework that consists of the Intellectual Property Rights from Publicly Financed Research and Development Act, as well as the Technology Innovation Agency Act, which could potentially influence research alliances (based on the Transactional Cost Economics, Resource-based View and Real Options Approach perspectives) with publicly financed research and development organisations. This was followed by the quantitative second phase, which attempted to verify the validity of a value-mediated governance mode model that included the highest ranked impact domains identified during the first phase as formative indicators for the perceived Intellectual Property Rights regime strength uncertainty factor. A qualitative online survey amongst senior managers at the Council for Science and Industrial Research, followed by Theme Extraction combined with Constant Comparative Method analysis, as well as a weighted frequency analysis, constituted the research methodology employed during the first phase’s identification and ranking of impact domains within the South African legislative framework. This phase demonstrated that the highest ranked impact domains (primarily driven by the Transactional Cost Economics perspective) included the choice of Intellectual Property Rights ownership, state walk-in rights on undeclared Intellectual Property, and benefit-sharing policies for the creators of Intellectual Property. The second phase consisted of a quantitative online survey, distributed amongst current and potential research alliance partners of the Council for Science and Industrial Research, followed by Structural Equation Modelling of a value-mediated governance model that included, amongst others, the perceived Intellectual Property Rights regime strength as an uncertainty factor. This phase revealed not only that the impact domains identified during the first phase could be used as formative indicators of the perceived Intellectual Property Rights regime strength, but also that stronger perceived regimes are positively related to the preference for quasi-hierarchy research alliance governance modes. Furthermore, it established that the expected value of a research alliance, which was shown to be positively influenced by the strength of the perceived Intellectual Property Rights regime, acted as a mediating factor on the relationship between the perceived Intellectual Property Rights regime strength and the preferred research alliance governance mode. Keywords: Bayh-Dole, Formative Indicators, Intellectual Property Rights, Research Alliances, Real Options Approach, Resource-based View, Quasi-Market Governance Modes, Quasi- Hierarchy Governance Modes, Structural Equation Modelling, Transactional Cost Economics, Value-mediated Governance Model. CopyrightDissertation (MBA)--University of Pretoria, 2012.Gordon Institute of Business Science (GIBS)unrestricte

Die wond sê dit aan my: die morele wêreldbeskouing van die |xam as eko-morele fenomenologie

Magister Artium - MADespite the loss of speakers of |xam, one of the 28 Khoisan languages once spoken across Southern Africa, a part of the heritage of these speakers can be found in predominantly two archives: that of Wilhelm H. I. Bleek and Lucy Lloyd (1911) and Gideon R. von Wielligh (1919-1921). The archives form the heart of Bushman* Studies, and has long since received attention in, amongst others, anthropology, literature, and linguistics. This study presents an investigation into the ethical views of the |xam, an investigation which, with the single exception of the studies of Antjie Krog (2004-), has not been undertaken in a philosophical tradition. Through a comparative study of texts across archival boundaries, I engage critically with the ethical views of the |xam, specifically the phenomenological nature of these views. To this end, I use the hermeneutical approach in African philosophy, an approach which focuses on identifying and analysing concepts in texts. The approach to ‘reading’ |xam texts remains, however, a burning issue, and the limit to which disciplinary boundaries are appropriate, is debatable (Wessels 2010). Consequently, and as a result of the relative density of the available texts, insights from anthropology, literature, linguistics and rock art are incorporated within the comparative study. I secondly bring the ethical views which are identified through the comparative analysis into conversation with the dominant ethical framework in African philosophy, namely Ubuntu. Where Ubuntu as been ‘read’ through various lenses (Van Niekerk 2013), a phenomenological approach is absent. Further, where Ubuntu, African ethics broadly, is generally regarded as humanist, a salient ecological consciousness is present in the |xam views. A comparison between Ubuntu and the |xam views therefore deepens the discourse around African ethics in general, and further provides insights into the unique nature of the ethical views of the |xam in particular. Through this I attempt to add value both to Bushman Studies and African philosophy, whilst highlighting an important voice unique to Africa which could be added to the burning discussion around ecological decay in the time of the Anthropocene

The isolation and characterisation of Xylophilus ampelinus

Bacterial blight, caused by Xylophilus ampelinus (PANAGOPOULUS) WILLEMS et al. is a destructive disease of grapevine (Vitis vinifera). Incubation of cuttings at 15 °C for three days under moist conditions significantly increased the number of isolated X. ampelinus colonies. This treatment facilitates the isolation of the pathogen from infected material from which it could previously not be isolated

Hearing the voices of children: self-reported information on children's experiences during research procedures

__Introduction:__ In paediatric research, there is a tension between what you can ask from a child and what is needed for the development of evidence-based treatments. To find an optimal balance in conducting clinical research and protecting the child, it is necessary to have empirical data on children's experiences. Until now, there are scarce empirical data on the experiences from the perspective of the child. In this manuscript, we describe the protocol of a twophase study measuring children's self-reported experiences during research procedures. __Methods and analysis:__ In the first phase of our study, we aim to interview approximately 40 children (6-18 years) about their self-reported experiences during research procedures. In the second phase, we will develop a questionnaire to measure children's experiences during research procedures in a quantitative way. We will use the interview outcomes for the development of this questionnaire. Next, we will measure the experiences of children during seven research procedures with this questionnaire. A one-month followup is conducted to investigate the emotional impact of the research procedures on the children. Children will be recruited from different research studies in three academic children's hospitals in the Netherlands. __Ethics and dissemination:__ The ethics committee of the VU University medical center evaluated both studies and indicated that there was no risk/discomfort associated, stating that both phases are exempt from getting

Birth Certificate of Jantje Hulst, February 27, 1847

Birth certificate of Jantje Hulst, born Feb. 15, 1847. Signed by her father, Jan Hendriks Hulst, and two witnesses on February 27, 1847 in Staphorst, Netherlands. Jantje was the mother of Rhoda Brinks LeCocq.https://nwcommons.nwciowa.edu/vanderhulst/1003/thumbnail.jp

Impact of intellectual property rights on the governance mode decisions of engineering managers during the establishment of research alliances with publicly funded entities

Strengthening intellectual property rights for publicly financed research and development (R&D) ensures that research organizations maximize the full national value of the intellectual property that they generate, but potential negative spillover effects on the perceived value of a research alliance might deter an existing alliance partner from continued collaboration or a potential alliance partner from future collaboration. This study, performed in 2010 within the context of the Council for Scientific and Industrial Research in South Africa, aimed to develop a structural equation modeling-based value-mediation governance decision-making model that will enable engineering managers at publicly financed R&D organizations to select optimal governance modes for the research alliances they are establishing to grow their organizations’ R&D capabilities.http://tandfonline.com/loi/uemj202018-09-30hb2017Gordon Institute of Business Science (GIBS)Graduate School of Technology Management (GSTM

Technology forecasting in the National Research and Education Network technology domain using context sensitive Data Fusion

Using inductive reasoning this paper develops a framework for the Structural Equation Modeling based context sensitive Data Fusion of technology indicators in order to produce Technology Forecasting output metrics. Data Fusion is a formal framework that defines tools, as well as the application of these tools, for the unification of data originating from diverse sources. Context sensitive Data Fusion techniques refine the generated knowledge using the characteristics of exogenous context related variables, which in the proposed framework entails non-technology related metrics. Structural Equation Modeling, which is a statistical technique capable of evaluating complex hierarchical dependencies between latent and observed constructs, has been shown to be effective in implementing context sensitive Data Fusion. For illustrative purposes an example model instantiation of the proposed framework is constructed for the case of the National Research and Education Network technology domain using knowledge gained through action research in the South African National Research Network, hypotheses from peer-reviewed literature and insights from the Trans- European Research and Education Network Association’s annual compendiums for National Research and Education Network infrastructure and services trends. This example model instantiation hypothesizes that a National Research and Education Network’s infrastructure and advanced services capabilities are positively related to one another, as well as to the contextual influence it experiences through government control. Also, positive relationships are hypothesized between a National Research and Education Network’s infrastructure and advanced services capabilities and its usage, which is defined as the technology forecasting output metric of interest for this example. Data from the 2011 Trans-European Research and Education Network Association compendium is used in the Partial Least Square regression analysis of the example model instantiation, which confirms all hypothesized relationships, except the postulation that a National Research and Education Network’s infrastructure and advanced services capabilities are positively related. This latter finding is explained by observing the prevalence of technology leapfrogging in the National Research and Education Network global community.The Council for Scientific and Industrial Research, as well as the University of Pretoria.http://www.journals.elsevier.com/technological-forecasting-and-social-change2017-10-31hb2016Graduate School of Technology Management (GSTM

Should all hip and knee prosthetic joints be aspirated prior to revision surgery?

Aims It is essential to exclude a periprosthetic joint infection (PJI) prior to revision surgery. It is recommended to routinely aspirate the joint before surgery. However, this may not be necessary in a subgroup of patients. The aim of our study was to investigate if specific clinical and implant characteristics could be identified to rule out a PJI prior to revision surgery. Methods We retrospectively evaluated clinical and implant characteristics of patients who underwent a hip or knee revision surgery between October 2015 and October 2018. Patients were diagnosed with a PJI according to the MSIS diagnostic criteria. Results A total of 156 patients were analyzed, including 107 implants that were revised because of prosthetic loosening and 49 because of mechanical failure (i.e. instability, malalignment or malpositioning). No PJI was diagnosed in the group with mechanical failure. In the prosthetic loosening group, 20 of 107 were diagnosed with a PJI (19%). Although there was a significantly lower chance of having a PJI with an implant age of > 5 years combined with a CRP < 5 mg/L, an infection was still present in 3 out of 39 cases (8%). Conclusion Implants with solely mechanical failure without signs of loosening and low inflammatory parameters probably do not require a synovial fluid aspiration. These results need to be confirmed in a larger cohort of patients. In case of prosthetic loosening, all joints need to be aspirated before surgery as no specific characteristic could be identified to rule out an infection