Archive for the ‘Faculty of Environmental Sciences’ Category

THE ANALYSIS OF THE RELIABILITY OF COMMON GPS NETWORKS NO: M. 029

September 29, 2016

Author: Ekpoikong Edidiong Eugene
Department: Surveying and Geoinformatics
Affiliation: Nnamdi Azikiwe University Awka

A geodetic control network should be carefully designed, constructed, observed, adjusted, analyzed and maintained in order for it to provide a full lifetime of useful control. Complex and very precise geodetic networks may require expert analysis in order to realize the full accuracy and precision of the surveying observations used to create them. In addition to precision analysis, reliability analysis (the detection of outliers/gross errors/blunders among the observations) has been measured using a technique pioneered by the geodesist Baarda. This work presents a research project on the analysis of the reliability of common GPS Networks using different techniques and methods. In this study, commonly used conventional methods (statistical test) and the redundancy method have been applied to two (2) GPS Networks with different characteristics. The baseline components ΔX, ΔY, and ΔZ of the GPS baselines have been taken as the measurements. The GPS networks were first adjusted using the MATRIX program and latter analyzed using the ADJUST program. The conventional methods (i.e. Data Snooping and Tau Test) were applied to the networks at different significant levels (0.05, 0.01 and 0.001). In GPS networks with redundant observations, choosing the significant level as 0.001 was sufficient to realize outlier detection procedure. Working with great significant levels produced unreliable results. For the redundancy number ri, the global relative redundancy was calculated. It was seen that an adjustment that in general has low redundancy numbers will have measurement that lack sufficient checks to isolate blunders, and thus the chance for undetected blunders to exist in the measurements is high. Conversely, a high overall redundancy number enables a high level of internal measurement checking and thus there is a lower chance of accepting measurements that contain blunders. Reliability analysis proves to be an effective method for network monitoring and a useful design tool when applied to GPS geodetic control networks. It should be considered when designing GPS control networks, especially those with specific requirement and error budget.GPS device manufacturers and Least-squares Adjustment software developers should be advised to incorporate reliability analysis in their programs for effective network analysis.

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DETERMINATION OF COMPONENTS OF THE DEFLECTION OF THE VERTICAL OF LOBI AREA MAKURDI BENUE STATE NIGERIA USING GPS (GNSS) AND PRECISE LEVELLING OBSERVATIONS. M 033

September 29, 2016

Author: Ameh Benjamin Mgbede
Department: Surveying and Geoinformatics
Affiliation: Nnamdi Azikiwe University Awka

The subject under consideration is a research work on the determination of components of the deflection of the vertical of Lobi area in Makurdi, Benue State using Geometric Method. The Geometric method of determining components of the deflection of the vertical involves the practical integration of Global Positioning System (GPS) GNSS observations and Precise leveling techniques. The results of the observations were used to compute the components of vertical deflection using the Least Squares adjustments. Using the method described, the deflections of the vertical components of the test point were determined. The estimated parameters are -3.18 ±0.60 and -2.25±0.43 arc seconds for the north-south and east-west components; respectively. The deflection of the vertical components at the same station was calculated using the EGM96 and EGM2008 spherical harmonic models. The associated standard errors of the processed vectors of the network were computed. The results obtained in magnitude are significant findings, demonstrating the ability of the method to resolve the deflection of the vertical components from GPS and precise leveling observations in local areas.

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PRACTICAL REALIZATION OF GEOID UNDULATIONS OF OKENYA TOWN, IDAH, NIGERIA, USING THE GRAVIMETRIC METHOD OF MODIFIED STOKES INTEGRAL

September 29, 2016

Author: Agaje Atebije Bruno
Department: Surveying and Geoinformation
Affiliation: Nnamdi Azikiwe University Awka

The aim of this project is to develop a gravimetric local geoid model for interpolating geoid undulation values to be used for transformation of ellipsoidal heights to Orthometric heights and vice-versa within the study area.. Ellipsoidal height is one of the three dimensional components of the GPS. The wide spread use of satellite- based positioning techniques, especially the GPS has lead to greater attention being placed on the precise determination of geoid undulations at the local, regional or global levels. Geoid models are being evaluated with the aim of directly determining the elevations of points within the confines of the model without necessary carrying out the much tedious spirit leveling techniques as done during geodetic works. In this project, the geoid undulations of the study area were evaluated. In implementing this work, terrestrial point gravity data was obtained using the absolute and relative methods of gravity data acquisition .Gravity data was obtained randomly within the confines of the study area as defined by the coordinate framework of: latitude from (070 06’ 55” to 070 09’ 55”) and longitude from (060 46’ 01” to 060 49’ 01”), gridded into thirty-six compartments at 30” interval. Gravity data reductions were carried out via the free air and bouguer plate corrections. A gravimetric geoid undulation model was thus computed from the available 295 gridded gravity anomalies using the modified stokes integral .Statistical analysis showed that the mean geoid undulation was (20.895m).Further analysis showed that the standard deviation and the variance as computed were found to be (0.7534357 and 0.5676653) respectively The evaluated geoid undulation profile was validated and interpolated using required data sets. In this respect, the standard deviation of geoid undulation as computed from stokes integral as compared to that obtained from the NAVCO Geoid height software were found to be (0.3157965) and 0.313212401) respectively. Similarly, their respective variances of geoid undulation were found to be (1.349578061) and (0.098102024) respectively. The average covariance function of the free air gravity anomalies was evaluated to a value of (11811.059) milligals and had an estimated root mean square (r.m.s) free air gravity anomaly value of 108.679 milligals. This determined local geoid model including the data sets will in no small measure contribute to the robustness of the national geodetic data infrastructure of the state in particular and the nation at large. Conclusion was drawn to the effect that The Gravimetric Geoid undulation and hence the geoid depicting Okenya has been successfully computed from 295 gridded gravity Anomalies with the mean Geoid Undulation value found to be 20.285m. It was recommended that all the required data sets such as Point gravity values, gravity anomaly data, Digital Terrain Models (DTMs), and Geo-potential models be made available in a viable and user friendly Database. In the same vein, efforts should be intensified for the realization of the completion of the gravity network of Nigeria, which had long been abandoned. It was recommended that all militating factors against the realization of the Nigerian geoid be addressed by the government so as to enjoy the derivable benefits associated with an effective and workable geoid model in varied surveying applications.

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TRANS-ATLANTIC SEX SLAVERY AND HUMAN TRAFFICKING IN NIGERIA: A VISUAL REPRESENTATION IN SCRAP METAL SCULPTURE

September 29, 2016

Author: Ajuorah Tochukwu Chikodili
Department: Fine and Applied Arts
Affiliation: Nnmadi Azikiwe University Awka

Scrap metal, as a medium of sculptural production, is not very popular among Nigerian Sculptors. Most serious contemporary sculptures are still done in traditional materials such as; clay, concrete, bronze and wood. This problem could be attributed to the fact that most of these scrap metals are mild steel which rust when exposed to atmospheric conditions. In view of this problem this work explores the possibility of achieving sculptures that are aesthetically pleasing, using scrap metals it also explores how they could be preserved against unfavorable atmospheric conditions .The scrap metal sculpture produced by the researcher was used in this study to address core social problems; sex-slavery and human trafficking in our society. The researcher employed both studio and literary approaches in the course of the research. The work revealed that art is one of the most effective ways of propagating positive change in the society. Again the use of scrap metal for sculptures could reduce waste in our environment in line with the popular idea of “Waste to Wealth”.

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THE CONTRIBUTIONS OF URBAN INFRASTRUCTURE TO RESIDENTIAL REAL ESTATE INVESTMENT VALUE IN AWKA

September 29, 2016

Author: Okpala Chukwunonso Arinze
Department: Estate Management
Affiliation: Nnamdi Azikiwe University Awka

The study analysed the contributions of urban infrastructure to residential real estate investment value in Awka. The problem was deficit of information on the impact of urban infrastructure to residential property investment value which affects the planner, investor or real estate developer in taking decisions. The study area Awka was divided into four (4) residential zones namely the core, transitional zone, peripheral zone and public housing estates. Six (6) infrastructure were identified as peculiar to residential properties in Awka. They include: electricity, water, drainage channel, refuse disposal facility, access road and security facility. Tenants of residential properties and estate surveyors practising in Awka made up the population of the study. Sampling technique adopted was stratified random sampling while the instrument for data collection was questionnaire. A total number of two hundred and fifty-six (256) questionnaires were used for the analysis. The study employed multiple regression model to determine the influence of infrastructure on rental values of residential properties in Awka while correlation co-efficient was used to determine the relationship between available infrastructures and rental values. It was found that annual rent increases when there is an increase in electricity supply, water supply and improvement on access roads. The study recommended that government should create an enabling environment for private sector participation in the development, management and improvement of infrastructure through policy formulation and establishment of a coordinating agency that will be involved in planning, development and maintenance of urban infrastructure in order to reduce existing deficiencies that affect residential real estate investment.

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