Facility Location Problems: Models, Techniques, and Applications in Waste Management

This paper presents a brief description of some existing models of facility location problems (FLPs) in solid waste management. The study provides salient information on commonly used distance functions in location models along with their corresponding mathematical formulation. Some of the optimization techniques that have been applied to location problems are also presented along with an appropriate pseudocode algorithm for their implementation. Concerning the models and solution techniques, the survey concludes by summarizing some recent studies on the applications of FLPs to waste collection and disposal. It is expected that this paper will contribute in no small measure to an integrated solid waste management system with specific emphasis on issues associated with waste collection, thereby boosting the drive for e�ective and e�cient waste collection systems. The content will also provide early career researchers with some necessary starting information required to formulate and solve problems relating to FLP

An Improved Location Model for the Collection of Sorted Solid Waste in Densely Populated Urban Centres

This paper presents a facility location model for improving the collection of solid waste materials. The model is especially suitable for densely populated regions with several housing units as well as encourages initial sorting of wastes. Each individual house in the collection area is designated a customer, with randomly selected customers comprising the set of candidate hubs. The fundamental feature of the model is to group the customers into clusters by assigning each customer (house) to the nearest hub. Each cluster is then assigned to exactly one waste collection site drawn from the set of potential collection locations. The objective is to minimize the total number of activated waste collection sites such that all the customers’ requests are satisfied without violating the capacity limit of each site. A simple Lagrangian relaxation heuristic is developed for the problem and solved with the CPLEX solver on the AMPL platform to find a feasible solution. Results from the numerical implementation of model show the model is efficient and competitive with existing solid waste collection facility location model

Relational Factors of Senior Secondary School Students’ Preference for Teaching Profession

This study investigated the Relational Factors of Students Preference for Teaching Profession. Six hundred Senior Secondary School II students and their parents were selected through multi stage sampling technique. Three instruments were used for data collection: Students Teaching Profession Preference Scale (r = 0.70), Salary and Incentive Scale (r = 0.89) and Parental career value scale (r = 0.51) validated using Cronbach Alpha Reliability Analysis. The data collected were analysed using descriptive statistics and multiple regression. Level of significance was taken to be 0.05. Students’ preference for teaching profession was found to be positive. It was also discovered that teaching profession is rated 5th out of 10 positions by parents. The study also revealed that parental career value, salary and gender compositely predict students’ preference for teaching profession (R=.291; F(3,471) =14.503, p < 0.05).Subsequently when the relative contribution of the independent variables were looked into, only salary was the significant influential variable (salary β = .287, t = 6.498, p < 0.05) while parental career value and gender were not. Based on the findings of this study, it was recommended that government motivate teachers with better salary and provide good working environment to improve the image of teachers. It was also recommended that Government, Policy makers, curriculum planners should set up a scheme to encourage hard working teachers by promoting them annually and sending them on training abroad

GIS – SUPPORTED ASSESSMENT OF LAND USE DYNAMICS OF ABEOKUTA METROPOLIS FROM 1960 T0 2005

The study identified and analyzed land use patterns between 1960 and 2005, and examined the forces underlying land use change and projects the future pattern of land use change in the study area. Both primary and secondary data collected were analyzed using descriptive statistics and geospatial techniques of GIS and Remote Sensing. The results showed that settlement land use which was 1253.12 hectares (3%) in 1972 increased by six fold to 7684.27 hectares (16%) in 1984 and by tenfold to 12842.11 hectares (27%) of the total land area in 2005. Farmlands reduced from 8751.21 hectares (19%) in 1972 to 7144.32 hectares (15%) in 1984 to 3824.80 (8%) in 2005. The result equally showed that between 1972 and 1984 the population grew by 75.16% while settlements increased by 513.21%. Also between 1972 and 2005 the population grew by 206.70 % and settlements increased by 924.81 %. The result of the predictive model developed for this study showed that settlement, bare surface, shrub and water body will increase by 60.30%, 57.68%, 53.79% and 8.03% respectively while non-forested, farmlands, forested wetlands and light forest will decrease by 9.5%, 28.55%, 12.35% and 26.76% respectively. There were continuous changes among the various land use classes identified.

Perception of in-school adolescents about adolescentfriendly characteristics of healthcare services received in Ibadan Metropolis, Nigeria

Introduction: Adolescence was previously assumed to be a diseases free stage of life. It is however now known that adolescents are not only&nbsp; involved in risky health behaviours but they also have their own share of health problems that other age groups face. The adolescent-friendly model helps to create adolescent-responsive health systems, Nigeria currently has no country-specific report on the adolescentfriendly characteristics of the health services rendered to her adolescents. This study identified various health problems for which in-school adolescents in Ibadan North-East Local Government Area sought healthcare and determined their perception of received healthcare services with regards to its “adolescent-friendliness”.Methods: This was a school-based cross-sectional study that utilized quantitative method of data collection. A multi-stage systematic random sampling technique was employed to select 500 students for school survey. Self-administered, semistructured questionnaire was used to collect data. Descriptive statistics and Chisquare test at α=0.05 were used for data analysis.Results: Perceived malaria (52.4%), acne (36.2%), menstrual pain (17.0%) and depression (3.0%) were the common health problems adolescents sought health care for. Majority of the adolescents perceived the health services received as being adolescent-friendly. These health services were perceived to be accessible by (87%), acceptable by (93.2%), appropriate by (81.4%), effective by (91.4%), and equitable by (82.2%) of the respondents. Adolescents who sought mental care perceived least adolescent-friendliness of received healthcare services.Conclusion: Adolescents in Ibadan currently view received health services as adolescent-friendly. However, the management of mental health&nbsp; problems in adolescents should incorporate adolescent friendly elements entrenched at every level of the health system. Keywords: In-school adolescents, Adolescent health problems, Adolescent-friendly health services, Health seeking behaviour,Nigeria

A Stable and Consistent Finite Difference Scheme for a Time-Dependent Schrodinger Wave Equation in a Finitely Low Potential Well

In this paper, we present a stable and consistent criterion to an explicit finite difference scheme for a time-dependent Schrodinger wave equation. This paper is a departure from the well-established time independent Schrodinger Wave Equation (SWE). We do this for a particular case of a finitely low potential wel

Abundance of birds in six selected habitats

Bird species world over are faced with the problem of habitat changes. Conservation of birds in fragments of habitats is increasingly important due to the diverse uses of the environment. To meet this challenge, predicting abundance of bird species in relation to specific vegetation taxa in the habitats is required .This study determined bird species abundance and their relationship with habitat variables of tree, shrub and herb abundance. Study conducted in the forested bitumen belt of Ode-Irele, Ondo state, Nigeria evaluated habitat use by birds using 20- minutes birds point count to a radius of 30 meters, carried out in six selected habitats. The vegetation cover was sampled using 5x5-meters and 1m2quadrants. Data collected were subjected to t-test of independent variables with LSD in ANOVA for birds’ use of habitats and linear regression for the dependence of birds’ abundance on habitats’ variables.88 bird species belonging to 31 families were associated with the study area. The abundance of birds was significantly affected by habitat types (P&lt;0.05) and predicted by habitat variables. The study would assist decision makers in the management and conservation of habitats’ variables critical to the survival of bird species during the bitumen development phase.Keywords: Abundance, Birds, Bitumen, Conservation, Habitats, Nigeri

A Test of Non-linear Conjugate Gradient Methods Via Exact Line Search

The conjugate gradient method provides a very powerful tool for solving unconstrained optimization problems. In this paper the non-linear conjugate gradient methods are tested using some benchmark non-polynomial unconstrained optimization functions. The task was accomplished by finding the exact values of the descent also known as the minimizing argument or rather the minimizer in each method. Findings also show that the basic requirement for exact convergence was satisfied by all the methods

A Review of Local Factors Affecting Solid Waste Collection in Nigeria

The knowledge of local and regional factors that affect effective solid waste collection plays an important role in choosing appropriate technology. Waste collection has grown to become a major challenge demanding daily response from waste managers and it becomes inevitable to provide stakeholders with necessary information to aid key decision-making. This paper provides a comprehensive and detailed review of local-based factors that affect waste collection in Nigeria. Literature study and on-site observation were used for getting theoretical and useful information on the collection of waste in the study area. The study considered various standard collection technologies and their supporting factors in order to assess the effectiveness of existing methods. The current collection techniques existing in different parts of the country together with unique local factors for these various areas are reported. The findings in many cases reveal that the method of waste collection adopted and equipment used are faced with many challenges. This paper revealed that there is no investment presently made on the existing development plan to initiate a modern waste collection system. The study recommends a new approach that could be used by institutions and government agencies for efficient municipal solid waste collection to achieve sustainable and effective sanitation which will consequently facilitate the development of an aesthetically balanced and friendly environmen

An Assessment of Wetland Loss in Lagos Metropolis, Nigeria

Wetlands are a very important subsystem of the general ecosystem as they play vital roles in the sustenance of both the surface and groundwater resources of the earth. However, much of the world’s wetlands have been lost due to series of human activities which gradually cause the degradation of this distinct element of ecosystem. The foundation of this problem is based on public perception of wetlands as unproductive, unhealthy lands, full of disease carrying insects and reptiles such as snakes and crocodiles. Therefore, this study assessed the loss of wetlands in Lagos metropolis. Questionnaires were administered on 75 Estate Surveyors and Valuers located within the study area and 76% were successfully retrieved. Also, 20 questionnaires were administered on conservation officials while 50% were retrieved. Data collected was collated and anlysed using descriptive statistics and relative importance index (RII). The study revealed that wetlands in Lagos Metropolis are habitats for fishes, source of water supply, help in sustaining the food chain of various wetland animals and are inevitably useful in maintaining the integrity of the Lagos coastline. The study further revealed urbanisation as a major factor responsible for the loss and degradation of wetlands in Lagos. Construction activities such as sand-filling, converting and reclaiming wetlands for the purpose of housing construction and infrastructural development contribute to wetland loss in Lagos metropolis. The study therefore concluded that efforts should be geared towards giving this natural ecosystem its due consideration when taking economic decision that will impact on it. Keywords: Environment, Lagos Metropolis, Wetland Loss, Wetland Valuation, Nigeri