DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN P... more DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MPA (LG) NOVEMBER,
Low back pain a musculoskeletal problem that affects about 50 to 80 percent of adults in the worl... more Low back pain a musculoskeletal problem that affects about 50 to 80 percent of adults in the world at some time caused by a problem in the muscle, ligaments, discs, joints or nerves of the spine. Despite the prevailing cases in Nigeria, there is no currently published data on assessment of MRI findings of patients with lower back pain in this region. A retrospective cross-sectional study using secondary data was carried out to sort out the causal effect of various MRI findings/investigations upon non-traumatic low back pain at the radiology department, of one of Nigerian Teaching Hospitals in Jos. 200MRI images comprising 108 males and 92 female of the lumbar spine for three years (2012-2014) of adults aged 18 – 80 years were used in the study and were evaluated according to age, sex, occupation and region on lumbar spine. Data was analysed for descriptive statistics such as percentage and mean using SPSS version 19.0. Results show that, patients with non-traumatic low back pain are...
The purpose of this study is to understand the current state of the Economic and Financial Crimes... more The purpose of this study is to understand the current state of the Economic and Financial Crimes Commission (EFCC) in terms of the successes and challenges in fighting corrupt related offences in Nigeria. The Study investigated the operational achievements of the Commission and the obstacles to achieving the mandate of the EFCC. This study adopted a qualitative research approach through a single case study design. Data were obtained using multiple sources (interviews, documentary evidence and observations) to answer the research questions. In all, 12 interviews were carried out during a period of three months. Senior, middle and first line management were purposively selected to participate in the research. The data gathered were analyzed using Nvivo 10. The result of the textual evidence reveals the apparent successes in the investigation, prosecution and conviction of corrupt offences in Nigeria. However, the context in which the agency exists remains its major obstacle, especial...
Increasing demand for transmission capacity due to digital revolution is causing an increasing de... more Increasing demand for transmission capacity due to digital revolution is causing an increasing demand for optical fiber systems. However, as bit-error-rate (BER) increases the fiber optic cable signal quality becomes degraded, causing signal delays, jitters, poor quality of service, packet loss, link outage, etc. In this study, the analysis of loss levels in a single mode fiber optic cable was carried out using the optical time domain reflectometer (OTDR), network monitoring system (NMS) and CACTI (V 1.1.38). Various OTDR traces were carried out to determine the loss levels in the fiber cores. Similarly, using the NMS, the actual link losses were calculated and compared with the loss budget to derive the link loss margin of the links; with a benchmark loss margin of 5 dB, high and low loss levels were determined. Lastly, bandwidth utilization was carried out using network graphical solution software (CACTI, V 1.1.38). The results show that, from the OTDR traces, 60% of the tested fiber cores had high losses at the spliced joints, whereas the analysis of the NMS shows 41.7% high losses. The bandwidth utilization analysis shows a reduction in fiber link availability by 8.3%. This work has revealed the different loss levels in the tested fiber cores with high loses leading to increase in BER which negatively impacts the optimum usability of a link. Therefore, maintaining a low and within-budget loss level is very essential for efficient signal transmission and optimization of the fiber optic cable for both manufacturers and the end users.
IEEE Transactions on Parallel and Distributed Systems, 2019
Concurrent search trees are crucial data abstractions widely used in many important systems such ... more Concurrent search trees are crucial data abstractions widely used in many important systems such as databases, file systems and data storage. Like other fundamental abstractions for energy-efficient computing, concurrent search trees should support both high concurrency and fine-grained data locality in a platform-independent manner. However, existing portable fine-grained locality-aware search trees such as ones based on the van Emde Boas layout (vEB-based trees) poorly support concurrent update operations while existing highlyconcurrent search trees such as non-blocking search trees do not consider fine-grained data locality. In this paper, we first present a novel methodology to achieve both portable fine-grained data locality and high concurrency for search trees. Based on the methodology, we devise a novel locality-aware concurrent search tree called GreenBST. To the best of our knowledge, GreenBST is the first practical search tree that achieves both portable fine-grained data locality and high concurrency. We analyze and compare GreenBST energy efficiency (in operations/Joule) and performance (in operations/second) with seven prominent concurrent search trees on a high performance computing (HPC) platform (Intel Xeon), an embedded platform (ARM), and an accelerator platform (Intel Xeon Phi) using parallel micro-benchmarks (Synchrobench). Our experimental results show that GreenBST achieves the best energy efficiency and performance on all the different platforms. GreenBST achieves up to 50% more energy efficiency and 60% higher throughput than the best competitor in the parallel benchmarks. These results confirm the viability of our new methodology to achieve both portable fine-grained data locality and high concurrency for search trees.
Purpose The purpose of this paper is to appraise the Nigerian Economic and Financial Crimes Commi... more Purpose The purpose of this paper is to appraise the Nigerian Economic and Financial Crimes Commission (EFCC) of their role in tackling systemic corruptions and to associate how institutional and organizational factors influence the performance of the EFCC. Design/methodology/approach Data were gathered through in-depth interviews, non-participatory observations and documentary analysis. Findings The results of the integrative analysis show that the EFCC has apparently been ineffective, and further improvization of the organization is needed. Poor performance of the EFCC was associated with factors such as lack of commitment, inefficient judiciary, insufficient budgets and incompetent personnel. Practical implications This study recommends further improvements in the form of a greater political will, improved legal process and also elevated budgetary funds and recruitment of personnel to the EFCC. Originality/value The study adopted a descriptive, qualitative case study approach to ...
Recent research has suggested that improving fine-grained data-locality is one of the main approa... more Recent research has suggested that improving fine-grained data-locality is one of the main approaches to improving energy efficiency and performance. However, no previous research has investigated the effect of the approach on these metrices in the case of concurrent data structures. This paper investigates how fine-grained data locality influences energy efficiency and performance in concurrent search trees, a crucial data structure that is widely used in several important systems. We conduct a set of experiments on three lock-based concurrent search trees: DeltaTree, a portable fine-grained locality-aware concurrent search tree; CBTree, a coarse-grained locality-aware B+tree; and BST-TK, a locality-oblivious concurrent search tree. We run the experiments on a commodity x86 platform and an embedded ARM platform. The experimental results show that DeltaTree has 13--25% better energy efficiency and 10--22% more operations/second on the x86 and ARM platforms, respectively. The results...
Like other fundamental abstractions for energy-efficient computing, search trees need to support ... more Like other fundamental abstractions for energy-efficient computing, search trees need to support both high concurrency and finegrained data locality. However, existing locality-aware search trees such as ones based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations while existing highly-concurrent search trees such as the non-blocking binary search trees do not consider data locality. We present GreenBST, a practical energy-efficient concurrent search tree that supports fine-grained data locality as vEB-based trees do, but unlike vEB-based trees, GreenBST supports high concurrency. GreenBST is a k-ary leaf-oriented tree of GNodes where each GNode is a fixed size tree-container with the van Emde Boas layout. As a result, GreenBST minimizes data transfer between memory levels while supporting highly concurrent (update) operations. Our experimental evaluation using the recent implementation of non-blocking binary search trees, highly concurrent B-trees, conventional vEB trees, as well as the portably scalable concurrent trees shows that GreenBST is efficient: its energy efficiency (in operations/Joule) and throughput (in operations/second) are up to 65% and 69% higher, respectively, than the other trees on a high performance computing (HPC) platform (Intel Xeon), an embedded platform (ARM), and an accelerator platform (Intel Xeon Phi). The results also provide insights into how to develop energy-efficient data structures in general. 100% 95% 90% 80% 50%
As other fundamental programming abstractions in energy-efficient computing, search trees are exp... more As other fundamental programming abstractions in energy-efficient computing, search trees are expected to support both high parallelism and data locality. However, existing highly-concurrent search trees such as red-black trees and AVL trees, do not consider data locality while existing locality-aware search trees such as those based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations. This paper presents DeltaTree, a practical locality-aware concurrent search tree that combines both locality-optimisation techniques from vEB-based trees and concurrency-optimisation techniques from non-blocking highly-concurrent search trees. DeltaTree is a k-ary leaf-oriented tree of DeltaNodes in which each DeltaNode is a size-fixed tree-container with the van Emde Boas layout. The expected memory transfer costs of DeltaTree's Search, Insert and Delete operations are O(log B N), where N, B are the tree size and the unknown memory block size in the ideal cache model, respectively. DeltaTree's Search operation is wait-free, providing prioritised lanes for Search operations, the dominant operation in search trees. Its Insert and Delete operations are non-blocking to other Search, Insert and Delete operations, but they may be occasionally blocked by maintenance operations that are sometimes triggered to keep DeltaTree in good shape. Our experimental evaluation using the latest implementation of AVL, red-black, and speculation friendly trees from the Synchrobench benchmark has shown that DeltaTree is up to 5 times faster than all of the three concurrent search trees for searching operations and up to 1.6 times faster for update operations when the update contention is not too high.
Proceedings of the 2015 ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems, 2015
Like other fundamental abstractions for high-performance computing, search trees need to support ... more Like other fundamental abstractions for high-performance computing, search trees need to support both high concurrency and data locality. However, existing locality-aware search trees based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations. We present DeltaTree, a practical locality-aware concurrent search tree that integrates both locality-optimization techniques from vEB-based trees, and concurrency-optimization techniques from highly-concurrent search trees. As a result, DeltaTree minimizes data transfer from memory to CPU and supports high concurrency. Our experimental evaluation shows that DeltaTree is up to 50% faster than highly concurrent B-trees on a commodity Intel high performance computing (HPC) platform and up to 65% faster on a commodity ARM embedded platform.
DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN P... more DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MPA (LG) NOVEMBER,
Low back pain a musculoskeletal problem that affects about 50 to 80 percent of adults in the worl... more Low back pain a musculoskeletal problem that affects about 50 to 80 percent of adults in the world at some time caused by a problem in the muscle, ligaments, discs, joints or nerves of the spine. Despite the prevailing cases in Nigeria, there is no currently published data on assessment of MRI findings of patients with lower back pain in this region. A retrospective cross-sectional study using secondary data was carried out to sort out the causal effect of various MRI findings/investigations upon non-traumatic low back pain at the radiology department, of one of Nigerian Teaching Hospitals in Jos. 200MRI images comprising 108 males and 92 female of the lumbar spine for three years (2012-2014) of adults aged 18 – 80 years were used in the study and were evaluated according to age, sex, occupation and region on lumbar spine. Data was analysed for descriptive statistics such as percentage and mean using SPSS version 19.0. Results show that, patients with non-traumatic low back pain are...
The purpose of this study is to understand the current state of the Economic and Financial Crimes... more The purpose of this study is to understand the current state of the Economic and Financial Crimes Commission (EFCC) in terms of the successes and challenges in fighting corrupt related offences in Nigeria. The Study investigated the operational achievements of the Commission and the obstacles to achieving the mandate of the EFCC. This study adopted a qualitative research approach through a single case study design. Data were obtained using multiple sources (interviews, documentary evidence and observations) to answer the research questions. In all, 12 interviews were carried out during a period of three months. Senior, middle and first line management were purposively selected to participate in the research. The data gathered were analyzed using Nvivo 10. The result of the textual evidence reveals the apparent successes in the investigation, prosecution and conviction of corrupt offences in Nigeria. However, the context in which the agency exists remains its major obstacle, especial...
Increasing demand for transmission capacity due to digital revolution is causing an increasing de... more Increasing demand for transmission capacity due to digital revolution is causing an increasing demand for optical fiber systems. However, as bit-error-rate (BER) increases the fiber optic cable signal quality becomes degraded, causing signal delays, jitters, poor quality of service, packet loss, link outage, etc. In this study, the analysis of loss levels in a single mode fiber optic cable was carried out using the optical time domain reflectometer (OTDR), network monitoring system (NMS) and CACTI (V 1.1.38). Various OTDR traces were carried out to determine the loss levels in the fiber cores. Similarly, using the NMS, the actual link losses were calculated and compared with the loss budget to derive the link loss margin of the links; with a benchmark loss margin of 5 dB, high and low loss levels were determined. Lastly, bandwidth utilization was carried out using network graphical solution software (CACTI, V 1.1.38). The results show that, from the OTDR traces, 60% of the tested fiber cores had high losses at the spliced joints, whereas the analysis of the NMS shows 41.7% high losses. The bandwidth utilization analysis shows a reduction in fiber link availability by 8.3%. This work has revealed the different loss levels in the tested fiber cores with high loses leading to increase in BER which negatively impacts the optimum usability of a link. Therefore, maintaining a low and within-budget loss level is very essential for efficient signal transmission and optimization of the fiber optic cable for both manufacturers and the end users.
IEEE Transactions on Parallel and Distributed Systems, 2019
Concurrent search trees are crucial data abstractions widely used in many important systems such ... more Concurrent search trees are crucial data abstractions widely used in many important systems such as databases, file systems and data storage. Like other fundamental abstractions for energy-efficient computing, concurrent search trees should support both high concurrency and fine-grained data locality in a platform-independent manner. However, existing portable fine-grained locality-aware search trees such as ones based on the van Emde Boas layout (vEB-based trees) poorly support concurrent update operations while existing highlyconcurrent search trees such as non-blocking search trees do not consider fine-grained data locality. In this paper, we first present a novel methodology to achieve both portable fine-grained data locality and high concurrency for search trees. Based on the methodology, we devise a novel locality-aware concurrent search tree called GreenBST. To the best of our knowledge, GreenBST is the first practical search tree that achieves both portable fine-grained data locality and high concurrency. We analyze and compare GreenBST energy efficiency (in operations/Joule) and performance (in operations/second) with seven prominent concurrent search trees on a high performance computing (HPC) platform (Intel Xeon), an embedded platform (ARM), and an accelerator platform (Intel Xeon Phi) using parallel micro-benchmarks (Synchrobench). Our experimental results show that GreenBST achieves the best energy efficiency and performance on all the different platforms. GreenBST achieves up to 50% more energy efficiency and 60% higher throughput than the best competitor in the parallel benchmarks. These results confirm the viability of our new methodology to achieve both portable fine-grained data locality and high concurrency for search trees.
Purpose The purpose of this paper is to appraise the Nigerian Economic and Financial Crimes Commi... more Purpose The purpose of this paper is to appraise the Nigerian Economic and Financial Crimes Commission (EFCC) of their role in tackling systemic corruptions and to associate how institutional and organizational factors influence the performance of the EFCC. Design/methodology/approach Data were gathered through in-depth interviews, non-participatory observations and documentary analysis. Findings The results of the integrative analysis show that the EFCC has apparently been ineffective, and further improvization of the organization is needed. Poor performance of the EFCC was associated with factors such as lack of commitment, inefficient judiciary, insufficient budgets and incompetent personnel. Practical implications This study recommends further improvements in the form of a greater political will, improved legal process and also elevated budgetary funds and recruitment of personnel to the EFCC. Originality/value The study adopted a descriptive, qualitative case study approach to ...
Recent research has suggested that improving fine-grained data-locality is one of the main approa... more Recent research has suggested that improving fine-grained data-locality is one of the main approaches to improving energy efficiency and performance. However, no previous research has investigated the effect of the approach on these metrices in the case of concurrent data structures. This paper investigates how fine-grained data locality influences energy efficiency and performance in concurrent search trees, a crucial data structure that is widely used in several important systems. We conduct a set of experiments on three lock-based concurrent search trees: DeltaTree, a portable fine-grained locality-aware concurrent search tree; CBTree, a coarse-grained locality-aware B+tree; and BST-TK, a locality-oblivious concurrent search tree. We run the experiments on a commodity x86 platform and an embedded ARM platform. The experimental results show that DeltaTree has 13--25% better energy efficiency and 10--22% more operations/second on the x86 and ARM platforms, respectively. The results...
Like other fundamental abstractions for energy-efficient computing, search trees need to support ... more Like other fundamental abstractions for energy-efficient computing, search trees need to support both high concurrency and finegrained data locality. However, existing locality-aware search trees such as ones based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations while existing highly-concurrent search trees such as the non-blocking binary search trees do not consider data locality. We present GreenBST, a practical energy-efficient concurrent search tree that supports fine-grained data locality as vEB-based trees do, but unlike vEB-based trees, GreenBST supports high concurrency. GreenBST is a k-ary leaf-oriented tree of GNodes where each GNode is a fixed size tree-container with the van Emde Boas layout. As a result, GreenBST minimizes data transfer between memory levels while supporting highly concurrent (update) operations. Our experimental evaluation using the recent implementation of non-blocking binary search trees, highly concurrent B-trees, conventional vEB trees, as well as the portably scalable concurrent trees shows that GreenBST is efficient: its energy efficiency (in operations/Joule) and throughput (in operations/second) are up to 65% and 69% higher, respectively, than the other trees on a high performance computing (HPC) platform (Intel Xeon), an embedded platform (ARM), and an accelerator platform (Intel Xeon Phi). The results also provide insights into how to develop energy-efficient data structures in general. 100% 95% 90% 80% 50%
As other fundamental programming abstractions in energy-efficient computing, search trees are exp... more As other fundamental programming abstractions in energy-efficient computing, search trees are expected to support both high parallelism and data locality. However, existing highly-concurrent search trees such as red-black trees and AVL trees, do not consider data locality while existing locality-aware search trees such as those based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations. This paper presents DeltaTree, a practical locality-aware concurrent search tree that combines both locality-optimisation techniques from vEB-based trees and concurrency-optimisation techniques from non-blocking highly-concurrent search trees. DeltaTree is a k-ary leaf-oriented tree of DeltaNodes in which each DeltaNode is a size-fixed tree-container with the van Emde Boas layout. The expected memory transfer costs of DeltaTree's Search, Insert and Delete operations are O(log B N), where N, B are the tree size and the unknown memory block size in the ideal cache model, respectively. DeltaTree's Search operation is wait-free, providing prioritised lanes for Search operations, the dominant operation in search trees. Its Insert and Delete operations are non-blocking to other Search, Insert and Delete operations, but they may be occasionally blocked by maintenance operations that are sometimes triggered to keep DeltaTree in good shape. Our experimental evaluation using the latest implementation of AVL, red-black, and speculation friendly trees from the Synchrobench benchmark has shown that DeltaTree is up to 5 times faster than all of the three concurrent search trees for searching operations and up to 1.6 times faster for update operations when the update contention is not too high.
Proceedings of the 2015 ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems, 2015
Like other fundamental abstractions for high-performance computing, search trees need to support ... more Like other fundamental abstractions for high-performance computing, search trees need to support both high concurrency and data locality. However, existing locality-aware search trees based on the van Emde Boas layout (vEB-based trees), poorly support concurrent (update) operations. We present DeltaTree, a practical locality-aware concurrent search tree that integrates both locality-optimization techniques from vEB-based trees, and concurrency-optimization techniques from highly-concurrent search trees. As a result, DeltaTree minimizes data transfer from memory to CPU and supports high concurrency. Our experimental evaluation shows that DeltaTree is up to 50% faster than highly concurrent B-trees on a commodity Intel high performance computing (HPC) platform and up to 65% faster on a commodity ARM embedded platform.
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