Distributed space-time block coding in cooperative relay networks with application in cognitive radio

Spatial diversity is an effective technique to combat the effects of severe fading in wireless environments. Recently, cooperative communications has emerged as an attractive communications paradigm that can introduce a new form of spatial diversity which is known as cooperative diversity, that can enhance system reliability without sacrificing the scarce bandwidth resource or consuming more transmit power. It enables single-antenna terminals in a wireless relay network to share their antennas to form a virtual antenna array on the basis of their distributed locations. As such, the same diversity gains as in multi-input multi-output systems can be achieved without requiring multiple-antenna terminals. In this thesis, a new approach to cooperative communications via distributed extended orthogonal space-time block coding (D-EO-STBC) based on limited partial feedback is proposed for cooperative relay networks with three and four relay nodes and then generalized for an arbitrary number of relay nodes. This scheme can achieve full cooperative diversity and full transmission rate in addition to array gain, and it has certain properties that make it alluring for practical systems such as orthogonality, flexibility, low computational complexity and decoding delay, and high robustness to node failure. Versions of the closed-loop D-EO-STBC scheme based on cooperative orthogonal frequency division multiplexing type transmission are also proposed for both flat and frequency-selective fading channels which can overcome imperfect synchronization in the network. As such, this proposed technique can effectively cope with the effects of fading and timing errors. Moreover, to increase the end-to-end data rate, this scheme is extended for two-way relay networks through a three-time slot framework. On the other hand, to substantially reduce the feedback channel overhead, limited feedback approaches based on parameter quantization are proposed. In particular, an optimal one-bit partial feedback approach is proposed for the generalized D-O-STBC scheme to maximize the array gain. To further enhance the end-to-end bit error rate performance of the cooperative relay system, a relay selection scheme based on D-EO-STBC is then proposed. Finally, to highlight the utility of the proposed D-EO-STBC scheme, an application to cognitive radio is studied

Effectiveness of meat and bone meal and distillers grain ash as a phosphorus source for crops

Non-Peer ReviewedProduction of biogas from organic materials via gasification also generates a valuable byproduct of ash. Ash contains the original nutrient present in organic materials, except carbon, nitrogen and sulfur that are lost as gases during this process. Therefore, the ash is concentrated in the important macronutrient of phosphorus and potassium. To determine the feasibility of land application of ash in providing phosphorus for crops, a study was carried out using Brown Chernozemic soil in growth chamber and field. This study aimed to investigate the influence of two ashes applied at three rates of P in comparison with mineral P fertilizer on crop yield, and P species that resided in soil after harvest using a sequential extraction procedure. The experimental treatments for the growth chamber study included 3 P sources: distillers grain ash, meat & bone meal ash and mono-calcium phosphate fertilizer. Each P source was applied at 3 rates: 25, 50 and 100 kg P ha-1 in addition to a control. Each treatment was supplemented with 200 kg urea-N ha-1 to ensure that N is not a limiting factor. For the field study, the experimental treatments consisted of the same P sources with 3 rates of application: 20, 40 and 80 kg P2O5 ha-1 plus a control. Each treatment was also supplemented with 100 kg urea-N ha-1. Analysis of ashes co-produced from gasification of distillers grain and meat & bone meal showed that they are rich in phosphorus, ranging from 13 – 16 % P. This high content of P was observed to benefit crop growth, providing a significant increase in crop yield compared to the control. Both ashes produced yields similar to that of mineral phosphorus, suggesting the high availability of ash P for plant uptake. A high proportion of residual P from the meat & bone meal ash was present in the form of calcium phosphate in the soil

Full-rate and full-diversity extended orthogonal space-time block coding in cooperative relay networks with imperfect synchronization

In this paper we present a novel extended orthogonal space-time block coding (EO-STBC) scheme for three and four relay nodes to use in asynchronous cooperative relay networks. This approach attains full-rate and full-diversity in that each hop attains unity rate and all four uncorrelated paths are utilized. Robustness against the effects of random delays at the relay nodes is enhanced through the use of a low-rate feedback channel. A new low complexity phase feedback scheme has been proposed which can retain the advantage of the perfect feedback scheme with substantial reduction in the feedback overhead. Orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP) is used at the source node to combat the timing errors at the relay nodes, which operate in a simple amplify-and-forward (AF) mode. Simulations show that our new scheme outperforms the previous schemes and uses a very simple symbol-wise maximum-likelihood (ML) decoder

Extended orthogonal space time block codes in wireless relay networks

In this paper we propose complex extended orthogonal space-time block codes (EO-STBCs) with feedback for wireless relay networks with the assumption of quasi-static flat fading channels. Full rate in each stage and full cooperative diversity for distributed EO-STBCs (D-EO-STBCs) are achieved by providing channel state information (CSI) at certain relay nodes. Two closed-loop schemes are proposed which make use of limited feedback from the destination node to a particular number of relay nodes, not exceeding half of the total number of such relay nodes. In our simulations, we use four relay nodes. Simulation results show that these two closed-loop D-EOSTBCs achieve full cooperative diversity in addition to array gain with linear processing. In particular, the proposed D-EO-STBCs designs preserve low decoding complexity and save both transmission power and total transmit time between source and destination

Sustainable Development, Entrepreneurship and Accounting Education: An Exploratory Study for Saudi Universities

This study aims to explore the role of accounting education programs in promoting the concepts of sustainability and entrepreneurship in Saudi society, by surveying the perceptions of a sample of parties related to accounting education - faculty members, students, and graduates - about the contribution of the intended learning outcomes of accounting programs in supporting knowledge and skills related to sustainability, entrepreneurship, and improving students positive attitudes towards these practices. The results of the study came to show, in general, the failure of accounting programs to support the concepts and practices of sustainability and entrepreneurship. The results shed light on some insights that could help in developing accounting programs, such as: Paying attention to some topics like environmental accounting and auditing, and ecological feasibility studies, developing teaching strategies to train students to analyze specific data to reach conclusions and solutions, inclusion of practical cases that depends on actual problems

Trimethylamine N-Oxide: The Good, the Bad and the Unknown

Trimethylamine N-oxide (TMAO) is a small colorless amine oxide generated from choline, betaine, and carnitine by gut microbial metabolism. It accumulates in the tissue of marine animals in high concentrations and protects against the protein-destabilizing effects of urea. Plasma level of TMAO is determined by a number of factors including diet, gut microbial flora and liver flavin monooxygenase activity. In humans, a positive correlation between elevated plasma levels of TMAO and an increased risk for major adverse cardiovascular events and death is reported. The atherogenic effect of TMAO is attributed to alterations in cholesterol and bile acid metabolism, activation of inflammatory pathways and promotion foam cell formation. TMAO levels increase with decreasing levels of kidney function and is associated with mortality in patients with chronic kidney disease. A number of therapeutic strategies are being explored to reduce TMAO levels, including use of oral broad spectrum antibiotics, promoting the growth of bacteria that utilize TMAO as substrate and the development of target-specific molecules with varying level of success. Despite the accumulating evidence, it is questioned whether TMAO is the mediator of a bystander in the disease process. Thus, it is important to undertake studies examining the cellular signaling in physiology and pathological states in order to establish the role of TMAO in health and disease in humans

The effect of the HLA B27 allele on the immune response to acute HCV in HIV infected patients

In mono-infected individuals, the HLA-B27 allele is strongly associated with spontaneous clearance of HCV in association with a strong CD8+ response targeted against a single epitope within the HCV RNA-dependent RNA polymerase (NS5B). We studied variation across the whole HCV genome and T cell responses over time in a rare cohort of HLA-B27+ patients with acute HCV and HIV co-infection, the majority of whom progressed to chronicity. We used next generation sequencing to detect changes within and outwith the immuno-dominant HLA-B27 restricted HCV-specific CD8+ T cell epitope NS5B2841-2849 (ARMILMTHF) during evolving progression of early HCV infection. Within the Acute HCV UK cohort, 10 patients carried the HLA B27 allele. Of these, 3/8 patients (37.5%) with HIV infection and 2/2 (100%) without HIV spontaneously cleared HCV (p=0.44). Sequential samples from nine HLA-B27+ patients (2 with monoinfection and 7 with HIV co-infection) were available for analysis (four spontaneous clearers and five evolving progressors). Mutations identified using NGS were assessed using a replicon genotype 1a system to evaluate viral fitness. Multiple mutations within the HLA-B27 restricted NS5B2841-2849 epitope were associated with progression to chroncity whereas patients who cleared the HCV infection spontaneously had no or only one mutation at this site (p=0.03). A triple NS5B2841-2849 mutant observed during progression to chronicity was associated with restored replication when compared to wild-type virus while single or double mutants were significantly associated with impaired replication (p=0.0495). T cell responses measured in these patients using ELISpot and flow cytometry. HLA-B27+ patients had significantly higher IFN-γ responses than patients who were HLA-B27- (p=0.0014). Those who progressed to chronicity had lower IFN-γ responses than those who cleared HCV (p=0.0011). Mono-infected patients had higher IFN-γ responses compared to co-infected patients (p=0.0015). HIV co-infection is associated with a lower likelihood of spontaneous clearance of HCV in HLA B27+ patients and this is associated with impaired T cell function in this group

Blockchain-enabled Reliable Osmotic Computing for Cloud of Things: Applications and Challenges

Cloud of Things (CoT) refers to an IoT solution consuming the cloud services of a single cloud vendor. In this paper, we have introduced the concept of a MultiCoT1 solution which refers to the collaborative execution of an IoT solution by multiple cloud vendors. Cloudlets and ad-hoc clouds are the extensions of centralized cloud services, closer to the user, in the form of fog and edge computing layers respectively and the Osmotic Computing (OC) serves as a glue by accomplishing the seamless compute sharing across these layers. The OC can also be integrated within a MultiCoT solution for extending it across three computational layers of cloud, fog and edge. However, this can only be achieved after establishing enough trust among all the vendors that are working in collaboration to simultaneously serve a particular MultiCoT solution. Blockchain has been already proven for establishing trust and supporting reliable interactions among independently operating entities. Hence, it can be used for establishing trust among the multiple cloud vendors serving a single MultiCoT solution. In this paper, we have presented the importance of using the proactive Blockchain-enabled Osmotic Manager (B-OM) for improving the reliability of OC. We have also highlighted the blockchain features that can improve the reliability of OC by establishing trust among the independently operating vendors of a MultiCoT solution, followed by the challenges associated with the integration of blockchain and OC along with the future research directions for achieving the proposed integration. © 2020 IEEE.Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works

Cyber Security Body of Knowledge and Curricula Development

The cyber world is an ever-changing world and cyber security is most important and touches the lives of everyone on the cyber world including researchers, students, businesses, academia, and novice user. The chapter suggests a body of knowledge that incorporates the view of academia as well as practitioners. This research attempts to put basic step and a framework for cyber security body of knowledge and to allow practitioners and academicians to face the problem of lack of standardization. Furthermore, the chapter attempts to bridge the gap between the different audiences. The gap is so broad that the term of cyber security is not agreed upon even in spelling. The suggested body of knowledge may not be perfect, yet it is a step forward