Implementing the required degree of multitenancy isolation : a case study of cloud-hosted bug tracking system

Implementing the required degree of isolation between tenants is one of the significant challenges for deploying a multitenant application on the cloud. In this paper, we applied COMITRE (COmponent-based approach to Multitenancy Isolation Through request RE-routing) to empirically evaluate the degree of isolation between tenants enabled by three multitenancy patterns (i.e., shared component, tenant-isolated component, and dedicated component) for a cloud-hosted Bug tracking system using Bugzilla. The study revealed among other things that a component deployed based on dedicated component offers the highest degree of isolation (especially for database transactions where support for locking is enabled). Tenant isolation based on performance (e.g., response time) favoured shared component (compared to resource consumption (e.g., CPU and memory) which favoured dedicated component). We also discuss key challenges and recommendations for implementing multitenancy for application components in cloud-hosted bug tracking systems with guarantees for isolation between multiple tenants

INTERFACE OF LEVERAGE AND EARNINGS: AN INVESTIGATION INTO THE NIGERIA MANUFACTURING SECTOR, CASE OF NIGRIA BREWERIES PLC

There is no doubt that financial and operating leverage are important because of the way these factors exert significant effect on the level and variability of returns, and consequently on the overall risk of a firm. An efficient mix of the two factors will minimize the incidence of business risk and financial risk. This work is concerned with assessing the variability in the stream of the firms’ residual earnings induced by the use of operating and financial leverages. The study has empirically employed the use of multiple regression analysis to investigate the impact of the two leverages on earnings and the emphasis is on the manufacturing sector. The result shows that sales, operating leverage, financial leverage and combined leverage have significant influence on earnings of NB Plc from 1979 – 2004

Evaluating degrees of tenant isolation in multitenancy patterns : a case study of cloud-hosted Version Control System (VCS)

One of the key concerns of implementing multitenancy (i.e., serving multiple tenants with a single instance of an application) on the cloud is how to enable the required degree of isolation between tenants, so that the required performance of one tenant does not affect other tenants. There is little research which provides empirical evidence on the required degree of isolation between tenants under different cloud deployment conditions. This paper applies COMITRE (COmponent-based approach to Multitenancy Isolation Through request RE-routing) to empirically evaluate the degree of isolation between tenants enabled by multitenancy patterns for cloud-hosted Version Control System (VCS). We implemented three multitenancy patterns (i.e., shared component, tenant-isolated component, and dedicated component) by developing a multitenant component using the FileSystem SCM plugin integrated within Hudson. The study revealed that dedicated component provides the highest degree of isolation between tenants (compared to shared component and tenant-isolated component) in terms of error% (i.e., the percentage of errors with unacceptably slow response times) and throughput. System load of tenants showed no variability, and hence did not influence the degree of tenant isolation for all the three multitenancy patterns. We also provide some recommendations to guide an architect in implementing multitenancy isolation on similar VCS tools like Subversion and CVS

Does Financial Deregulation Spurs Economic Development in Nigeria?

The problem of low investment caused by mismanagement of the financial deregulation process is a worrisome issue that needs to be addressed. Data spanning 46 years from 1970 to 2016 and which are relevant to variables of study like gross fixed capital formation, etc were gathered from secondary sources and analyzed using the Auto-Regressive Distribution Lag model. The result showed that both financial deregulation and investment growth have a long-term but negative significant impact on economic development. The paper recommends amongst others that the deregulation process needs to be properly sequenced into the financial syste

Road safety, alcohol consumption and visual function of motor bike riders in Ekpoma, Edo State, Nigeria

Causes of road traffic accidents (RTA) in developing nations have been attributed in part, to poor vision due to excessive alcohol consumption. This cross-sectional study assessed the visual acuity of 230 male motor-bike riders in Ekpoma, Edo State, Nigeria, and their potentials for alcohol abuse, using the cluster sampling technique.A semi-structured interviewer/self administered questionnaire was used to collect data on socio-demographic characteristics, road traffic accidents and alcohol use, while visual acuity was assessed with a Snellens chart. Results showed good right and left eye vision among 68.3% and 71.3% of the riders respectively, but visual impairment was observed among 25.2% (right) and 26.5% (left) of the riders, and the impairment was severe among 6.5% (right) and 2.2% (left) of them. Up to 69.57% had potential for alcohol abuse, while 5.22% and 25.22% had borderline or no potential for alcohol abuse respectively. About half of the respondents (118; 51.3%) have had a road traffic accident in the last one year and there was a statistically significant association between visual acuity and road traffic accidents (P = 0.000). Although majority of respondents had good visual acuity and a high potential for alcohol abuse, there involvement in road traffic accidents was low.Keywords: Poor vision, Visual acuity, Road traffic accident, Alcohol abus

Medical cost of Lassa fever treatment in Irrua Specialist Teaching Hospital, Nigeria

This cross-sectional study sought to estimate the direct medical cost of Lassa fever treatment on patients in South-South  Nigeria. All the 73 confirmed Lassa fever cases admitted in the isolation ward of the Institute Of Lassa Fever Research and  Control, Irrua Specialist Teaching Hospital (ISTH) Irrua, in Edo State, Nigeria, between May 2015 and May 2016 were  studied. A checklist was used to collect data on the socio-demographic characteristics and medical cost incurred by the  patients. Data entry and analysis was done using SPSS version 20. The average total direct cost for Lassa fever treatment  was N86,802.63 per patient for the subsidized treatment and N205,558.99 per patient for the unsubsidized treatment.  Medications accounted for the highest unsubsidized payments (N86,929.55; 42.10%) while hospital care accounted for the  highest cost component of he subsidized payments (N19,756.51; 22.76%). Up to 84.28% of medication and 70.8% of  investigations was subsidized making a total of 57.77% subsidy in the average total payments per patient. For an average  Nigerian, direct cost of treatment of Lassa fever is still expensive despite subsidy in medications and investigations.  Therefore efforts geared towards reducing the economic burden of Lassa fever on patients and their families are advocated.Keywords: Lassa fever, medical cost, poverty-reduction, South-South Nigeri

A Systematic Literature Review on Mergers and Acquisitions: A Bibliometric Analysis Approach

Many studies have examined the effects of mergers and acquisitions, but their results vary significantly. Thus, mergers and acquisitions are one of the most popular corporate restructuring activities undertaken by various organizations, institutes, companies (both private and public), agencies, and establishments, all in a quest to achieve the desired aim of the companies. But a pertinent question exists as to if mergers and acquisitions (M&A) have produced the desired goals and objectives of the companies. Therefore this study aims to examine the results, empirical preference, and author's opinions of existing literature as to if M&A had produced synergy gains or not. Bibliometric analysis is the methodological procedure used in this study. A total number of fifty (50) high-profile literatures were qualitatively examined, and it shows that M&A produced synergy gains to the level of 48%. From the analysis, M&A was also found not to produce synergy gain to the level of 28%, thus making the remaining 24% to be associated with authors whose views weren't explicit and those that are undecided to M&A producing synergy gains. This review study recommends that horizontal mergers and acquisitions be encouraged to increase the companies' market share, leading to their desired goals and objectiv

Optimal deployment of components of cloud-hosted application for guaranteeing multitenancy isolation

One of the challenges of deploying multitenant cloud-hosted services that are designed to use (or be integrated with) several components is how to implement the required degree of isolation between the components when there is a change in the workload. Achieving the highest degree of isolation implies deploying a component exclusively for one tenant; which leads to high resource consumption and running cost per component. A low degree of isolation allows sharing of resources which could possibly reduce cost, but with known limitations of performance and security interference. This paper presents a model-based algorithm together with four variants of a metaheuristic that can be used with it, to provide near-optimal solutions for deploying components of a cloud-hosted application in a way that guarantees multitenancy isolation. When the workload changes, the model based algorithm solves an open multiclass QN model to determine the average number of requests that can access the components and then uses a metaheuristic to provide near-optimal solutions for deploying the components. Performance evaluation showed that the obtained solutions had low variability and percent deviation when compared to the reference/optimal solution. We also provide recommendations and best practice guidelines for deploying components in a way that guarantees the required degree of isolation

Detoxifying effect of Nelumbo nucifera and Aegle marmelos on hematological parameters of Common Carp (Cyprinus carpio L.)

The objective of this study was to investigate the efficacy of Nelumbo nucifera and Aegle marmelos on common carp exposed to sub-lethal concentrations of combined heavy metals (5 ppm) under laboratory conditions. The fish were treated with Nelumbo nucifera (500 mg/kg bwt) and Aegle marmelos (500 mg/kgbwt) for 30 days as a dietary supplement. The blood biochemical parameters of the fish were evaluated by analyzing the level of red blood cells (RBC), packed cell volume (PCV), hemoglobin concentration, glucose, cholesterol, iron and copper. The findings of the present investigation showed significant increase in hemoglobin (p<0.001), RBC (p<0.01) and PCV (p<0.01) of herbal drug-treated groups compared with metal-exposed fish. Conversely, glucose and cholesterol level in blood of common carp showed significant reduction compared with heavy-metal-exposed groups. All the values measured in Nelumbo nucifera and Aegle marmelos treated fish were restored comparably to control fish. Our results confirmed that Nelumbo nucifera and Aegle marmelos provide a detoxification mechanism for heavy metals in common carp