Refereed Journals

The standard forward transformation for the direct conversion of curvilinear geodetic coordinates (φ, γ, Η) to its associated Cartesian coordinates (E, N, Z) has become a major challenge in most countries. This is due to the non-existence of the ellipsoidal height (h) in the modelling of their local geodetic reference network. Numerous studies in the past and recent years have suggested various mathematical techniques for predicting and estimating local ellipsoidal heights. Primary data used for the studies comprises of topographic data obtained from a survey in the Ghana urban water supply project in the Greater Kumasi Metropolitan Area (GKMA).This study considered an empirical evaluation of soft computing techniques such as Back Propagation Artificial Neural Network (BPANN), Generalized Regression Neural Network (GRNN), Radial Basis Function Artificial Neural Network (RBFANN) and conventional methods such as Polynomial Regression Model (PRM), Autoregressive Integrated Moving Average (ARIMA) and Least Square Regression (LSR). The motive is to apply and assess for the first time in our study area, the working efficiency of the aforementioned techniques. Each model technique was assessed based on statistical hypothesis (F, t) tests and performance criteria indices such as arithmetic mean error (AME), arithmetic mean square error (AMSE), minimum and maximum error value, and arithmetic standard deviation (ASD). The statistical analysis of the results revealed that, RBFANN, GRNN, BPANN, LSR, ARIMA and PRM, successfully estimated the ellipsoidal heights for the study area. However, the ANN models (RBFANN, BPANN, GRNN) outperforms the conventional models (LSR, PRM, ARIMA) in terms of accuracy and precision in estimating the local ellipsoidal heights. Also, statistical findings revealed that RBFANN produced more reliable results compared with the other methods. The main conclusion drawn from this study is that, the method of using soft computing is very much promising and can be adopted to solve some of the major problems related to height issues in Ghana. This study seeks to contribute to the existing knowledge on establishing a precise geodetic vertical datum in Ghana for national heightening purpose.

In this study, an integrated approach of a GIS - based Least Cost Path Analysis (Dijsktra Algorithm) and Multi-criteria decision methods (MCDM) techniques comprising of ENTROPY and TOPSIS was employed for the selection of the optimal route from Aflao to Elubo based on calculation of the cost grid surface in the ArcGIS environment. Topographic data containing digital elevation models, forest reserves, drainage features, land use and settlement data were used for the study. The results showed a model of an optimal route with a length of 471.34 kilometers as against the 540.60 kilometer distance by road. Hence, saving a travel distance of 69.26 kilometers. Also, the proposed distance of the Trans-ECOWAS line was approximately 498 kilometers, which is about 26.66 kilometers further distance compared to the optimal route proposed by this studies. Hence, an economical route has been proposed in terms of time, travel and construction cost. The route passes through four (4) coastal regions. Towns located along the route in the Volta Region includes; Aflao, Tokpo, Mepe, Gefia and Weija, Ablekuma, Ofankor and Mobole are among the towns in the Greater Accra Region found along the stretch. In the Central Region; Efutu, Amissakrom, Ewuoyaa, Mankessim, Apaa and Gomoa Lome are located along the proposed route. Towns along the stretch in the Western Region includes Pataho, Ashiaem, Agege, Amoakwasuazo and completes at Elubo. The optimal route will achieve the lowest cost of railway construction based on calculation of the cost raster layers.

Existing studies indicate that the construction sector is critical to the integration of sustainable public-works procurement towards the achievement of the Sustainable Development Goals 12.7 (SDGs). However, significant impediments to effective and efficient compliance with sustainable public-works procurement exist. The focus of this study is to identify the specific barriers to compliance with Sustainable Public-works Procurement. Through a scientific literature review and questionnaire survey, seventeen (17) barriers were identified and analyzed using the Principal Component Analysis (PCA) variant of factor analysis to assess the significant barriers to sustainable public-works procurement. Four clusters of factors were concluded as critical barriers to compliance with sustainable public-works procurement at the tender evaluation stage. (1) sustainable adaptability cluster; (2) managerial challenges cluster; (3) knowledge incapacity cluster; and (4) legal, policy, and evaluation cluster. The study presents a basis for experts along with researchers to appreciate the barriers to compliance and the need to improve compliance with sustainable public-works procurement in Ghana. The study adds to the pool of knowledge and provides the first survey on the specific barriers that inhibit compliance with sustainable public works procurement at the tender evaluation stage in Ghana.

This article assesses the impact of the COVID-19 outbreak on the urban motorcycle taxi (MCT) sector in Sub-Saharan Africa (SSA). MCT operators in SSA provide essential transport services and have shown ingenuity and an ability to adapt and innovate when responding to different challenges, including health challenges. However, policymakers and regulators often remain somewhat hostile toward the sector. The article discusses the measures and restrictions put in place to reduce the spread of COVID-19 and key stakeholders’ perspectives on these and on the sector’s level of compliance. Primary data were collected in six SSA countries during the last quarter of 2020. Between 10 and 15 qualitative interviews with key stakeholders relevant to the urban MCT sector were conducted in each country. These interviews were conducted with stakeholders based in the capital city and a secondary city, to ensure a geographically broader understanding of the measures, restrictions, and perspectives. The impact of COVID-19 measures on the MCT and motor-tricycle taxi sector was significant and overwhelmingly negative. Lockdowns, restrictions on the maximum number of passengers allowed to be carried at once, and more generally, a COVID-19-induced reduction in demand, resulted in a drop in income for operators, according to the key stakeholders. However, some key stakeholders indicated an increase in MCT activity and income because of the motorcycles’ ability to bypass police and army controls. In most study countries measures were formulated in a non-consultative manner. This, we argue, is symptomatic of governments’ unwillingness to seriously engage with the sector.

The Superior Performing Asphalt Pavements (Superpave) system – comprising asphalt binder grading, mixture design and mixture performance evaluation – has been in existence for nearly 30 years and has been implemented or evaluated for possible adoption in several countries to help address fatigue cracking, rutting and thermal cracking. These asphalt pavement distresses minimize pavement integrity to cause significant increase in maintenance cost, safety risks and roughness. Premature fatigue cracking and rutting failures are common in Ghana. Currently, only the mixture design component of the Superpave system is an option in the country's standard construction specification; asphalt binder selection is based on viscosity grading. Recently, very few projects have utilized Superpave-graded binders, and some of the binder grade selections were problematic. The use of Superpave-graded binders on high-volume roads is anticipated to become a common practice in the foreseeable future. However, there is no road agency guidance document on Superpave binder grade selection in Ghana currently, and this study sought to fill the gap. Such a guidance document will facilitate binder grade selection and streamline binder grade selection practices. This study utilized 42 years (1979–2020) of air temperature data collected from 24 weather stations across the country and measured asphalt pavement temperature to evaluate four existing Superpave binder grade prediction models. The model derived from the Long-Term Pavement Performance program better represented Ghana's climatic conditions and suggested the country may be partitioned into two Superpave binder grade selection zones: the Northern Savannah zone and the Transition/Forest/Coastal zone. At 98% reliability level, a binder grade of PG 70–10 was determined for the northern sector and PG 64–10 for the rest of the country. These are base binder grades (based on weather only) which must be adjusted for traffic conditions at the project site. Research should focus on local model formulation for refined Superpave binder grade selection and, during construction, selected binder grades must be verified through laboratory testing. Proper binder grade selection must be supplemented with effective pavement design, construction, axle load control and maintenance for good pavement performance and longevity.