Design and analysis of memristor-based reliable crossbar architectures

The conventional transistor-based computing landscape is already undergoing dramatic changes. While transistor-based devices’ scaling is approaching its physical limits in nanometer technologies, memristive technologies hold the potential to scale to much smaller geometries. Memristive devices are used majorly in memory design but they also have unignorable applications in logic design, neuromorphic computing, sensors among many others. The most critical research and development problems that must be resolved before memristive architectures become mainstream are related to their reliability. One of such reliability issue is the sneak-paths current which limits the maximum crossbar array size. This thesis presents various designs of the memristor based crossbar architecture and corresponding experimental analysis towards addressing its reliability issues. Novel contribution of this thesis starts with the formulation of robust analytic models for read and write schemes used in memristive crossbar arrays. These novel models are less restrictive and are suitable for accurate mathematical analysis of any mn crossbar array and the evaluation of their performance during these critical operations. In order to minimise the sneak-paths problem, we propose techniques and conditions for reliable read operations using simultaneous access of multiple bits in the crossbar array. Two new write techniques are also presented, one to minimise failure during single cell write and the other designed for multiple cells write operation. Experimental results prove that the single write technique minimises write voltage drop degradation compared to existing techniques. Test results from the multiple cells write technique show it consumes less power than other techniques depending on the chosen configuration. Lastly, a novel Verilog-A memristor model for simulation and analysis of memristor’s application in gas sensing is presented. This proposed model captures the gas sensing properties of titanium-dioxide using gas concentration to control the overall memristance of the device. This model is used to design and simulate a first-of-its-kind sneak-paths free memristor-based gas detection arrays. Experimental results from a 88 memristor sensor array show that there is a ten fold improvement in the accuracy of the sensor’s response when compared with a single memristor sensor

Evaluation of the feeding efficiency of three systems in feeding large roll hay packages

This experiment dealt with three systems for feeding large round hay packages to beef animals and with animal performance (weight gain) associated with outside-stored and inside-stored large round bales of bermudagrass hay. Feeding trials were conducted at the end of a four-month storage period to determine the amount of hay refused and tramped into the mud by cattle. The amount of hay wasted during the feeding trials was used to determine the cost-benefit ratio for each type of feeding equipment. Results indicated that larger amounts of hay were wasted from the panel feeder than from the roofed or unroofed feeder (17 percent, 7 percent and 9 percent dry matter loss respectively). Cattle fed inside stored hay performed better (gained more weight per day) than cattle fed outside-stored hay. Based on the data collected from this study, hay saved by the roofed feeder did not justify the cost of using the roofed bunk for bermudagrass hay (at $46/ton, annual value of hay saved amounted to$74 compared to an annual cost for the roofed feeder above that of the panel of $108. Annual value of hay saved by the unroofed feeder amounted to$59 compared to an annual cost for the unroofed feeder above that of the panel of $64)

Evaluation of antibacterial properties of tannins isolated from Dichrostachys cinerea

Compounds of pharmacological interest (tannins) were isolated from Dichrostachys cinerea and assayed against Staphylococcus aureus, Shigella boydii, Shigella flexneri, Escherichia coli and Pseudomonas aeruginosa using the agar diffusion method. Tannins exhibited antibacterial activities against all the test microorganisms. Sh. flexneri was the most resistant to tannins isolated from the plant material followed by Sh. boydii, E. coli, Staph. aureus and P. aeruginosa respectively. Minimuminhibitory concentration of the tannins ranged between 4.0 and 5.5 mg/ml while the minimum bactericidal concentration ranged between 4.5 and 6.0 mg/ml

Modeling water demand in a growing public university in Nigeria

Nigerian university campuses are facing the twin problems of providing portable water of adequate quantity and quality and the  sustainability of such supply. This paper examines the water demand status of a public University in Nigeria. Domestic, Public and Industrial water uses were considered while population forecasting was done using regression analysis for a 30 years design period (2018 – 2048). Results reveals possible population increase of 53.8 % by 2048 when the institution will clock 60 years. Water demand is also expected to rise sharply from 5,206 m3 day -1 (2018) to 10,959 m3 day -1 (2048); existing storage capacity cannot satisfy the current needs not to talk of the projected demand hence, a reservoir of about 11,000 m3 will be needed to service the university for the next 30 years; attracting more investments into the water supply system becomes imperative as the existing supplies from groundwater is unsustainable. Keywords: Water Demand; Population; University; Sustainability; Growt

Effective water governance through the paradigm of IWRM

The paper has defined effective water governance from the purview of the Global Water Partnership (GWP) and its activities which are based on the paradigm of Integrated Water Resources Management. IWRM and the advancement of its tools as recipe for the realization of Effective Water Governance have been elaborated upon. The principles, challenges and recipe for effective water governance have been presented based on the plethora of global, regional and national dialogues on effective water governance being organized by GWP

ANALYZING EMPLOYEE ATTRITION USING DECISION TREE ALGORITHMS

Employee turnover is a serious concern in knowledge based organizations. When employees leave an organization, theycarry with them invaluable tacit knowledge which is often the source of competitive advantage for the business. In order foran organization to continually have a higher competitive advantage over its competition, it should make it a duty to minimizeemployee attrition. This study identifies employee related attributes that contribute to the prediction of employees’ attritionin organizations. Three hundred and nine (309) complete records of employees of one of the Higher Institutions in Nigeriawho worked in and left the institution between 1978 and 2006 were used for the study. The demographic and job relatedrecords of the employee were the main data which were used to classify the employee into some predefined attrition classes.Waikato Environment for Knowledge Analysis (WEKA) and See5 for Windows were used to generate decision tree modelsand rule-sets. The results of the decision tree models and rule-sets generated were then used for developing a a predictivemodel that was used to predict new cases of employee attrition. A framework for a software tool that can implement therules generated in this study was also proposed.Keywords: Employee Attrition, Decision Tree Analysis, Data Minin

Assessing Local Community Participation in Tourism Planning and Development in Erin-Ijesha Waterfall Osun State, Nigeria

The basic element of tourism planning and development is to encourage the local communities’ participation as it is central to the sustainability of tourism industry. Many literatures have suggested a number of roles local communities could play in tourism development but failed as to how the locals themselves feel about this. This paper therefore focuses on Erin-Ijesha community participation in tourism development by examining their views on their role in the planning and development of Erin-Ijesha Waterfall resort. Data were gathered by reviewing office records and academic books, administration of 205 questionnaire and field observation. Descriptive statistics were used to analyze data collected for the study. Findings revealed that local communities want to be involved when tourism policies are being made to enable policy makers to prepare a policy that meets stakeholders’ needs and addresses  their concerns. The locals also want to be actively involved on decisions bothered on tourism development to ensure their needs are incorporated. Also, they equally want to a voice in development issues generally to enable them protect their community’s norms, values and interests and increase transparency and equity. The findings also revealed that the locals are against the prevailing ‘top-down’ approach in decision making when it comes to tourism development in their areas. Keywords: Erin-Ijesha, local community, Tourism planning, sustainabilit

Audit of Open Pediatric Tracheostomies at the University College Hospital, Ibadan

Background: Tracheostomy is the creation of a communication between the trachea and the overlying skin, maintained by a tube. This is done either by an open or percutaneous technique. Anatomical and physiological variation of the paediatric trachea and adjoining structures necessitates finite skills and consistent competence in performing pediatric tracheostomies, lack of which may cause higher mortality and morbidity outcome in tracheostomies in the pediatric age group. Objectives: There are inadequate local data on the outcomes of pediatric tracheostomies; therefore, we conducted a local audit of pediatric tracheostomy to describe our experience. Methods: A retrospective study of pediatric patients who had tracheostomies from June 2011 to December 2017 was done. Results: Thirty‑four patients were identified, all of whom had an open tracheostomy. The age range was 3 weeks to 16 years; M: F ratio was 2.4:1. Indications for surgery were obstructive (88.2%) and prolonged‑assisted intubation (11.8%). Recurrent respiratory papillomatosis, retropharyngeal abscess, and foreign‑body aspiration were the main obstructive causes. Three patients (8.8%) had repeat procedures, and these patients were initially discharged on tracheostomy tube and instructions were given for home care. Conclusion: Despite the evolving local challenges peculiar to clinical practice in developing countries, the outcome of pediatric tracheostomy in our hospital is good. Keywords: Audit, pediatric, tracheostom

DESIGN OF AN INTEGRATED AGRARIAN DATA DIMENSIONAL DATA WAREHOUSE

The concept of the Data warehouse was developed to provide a single access point to data from a variety of sources. There isa need to have a single location for the storage and sharing of data that users can easily utilize to make effective and qualitybusiness decisions, rather than trying to traverse the multiple data sources that exist today. Although many frameworks havebeen developed to integrate these sources into a single database, a reliable framework has yet to be developed. A majorhindrance to achieving a reliable warehouse is the poor quality of data obtained from the data transformation stage in theextract, transfer and load process. This poor quality of data contributes to inaccurate and unreliable results and if this data isused for decision making, unforeseen critical business errors can occur. This work reviews the data integration andtransformation process in dimensional data warehouses and proposes a dual structure for data integration and metadata ofmulti-formatted data used for the design of dimensional data warehouse using Agrarian data collected from Ondo State,Nigeria as a case study.Keywords: Data Warehouse, Data Integration, Metadata, Agrarian data