College of Engineering

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A 40–100 MHz phase-locked loop frequency synthesizer with built-in self-test
(2012) Yankey, Jephthah
The Phase locked loop (PLL) is one of the most important devices in modern electronic systems. PLLs are widely used for clock generation or frequency synthesis in communication systems, computers, radio and other electronic applications. However, due to the use of expensive external equipment and amount of time involved, traditional VLSI testing methods are inefficient for testing of PLLs. In this thesis, a fully functional PLL frequency synthesizer which operates from 40MHz to 100MHz is designed. The designed PLL exhibits phase noise of -71dBc/Hz at 1kHz, which is low enough for a wide array of applications. To solve the testing problem, Built-In Self-Test (BIST) is employed. A BIST scheme based on a defect-oriented method of testing is proposed. A prototype adds BIST circuitry, a good part of which is derived from existing components of the original design. The PLL BIST scheme is generic and hence portable to similar PLL designs. One significant addition unit is a simple response collector that combines shifting and counting functionalities. The entire system is designed in a typical CMOS process using a 3V power supply which is commonly found in today’s portable products. Spectre® simulations of the PLL show that it is capable of synthesizing any frequency between 40 and 100MHz within a reasonably short acquisition time. The output waveform of the generated signal is clean and shows no spikes whatsoever. Experimental simulations also reveal that the BIST circuitry is capable of generating the exact test pattern needed. It also performs efficiently all the unique checks which make up the PLL BIST. The final test output is very consistent and produces the same results for a number of different runs of the simulation.
A Security Shield for Internet of Things (IoT) Devices
(KNUST, 2019-06) Justice Owusu, Agyemang
The Internet of Things (IoT) is a new paradigm that enables the convergence of smart objects and the internet. It is an intelligent network that connects all things to the Internet for the purpose of exchanging information and communicating through the information sensing devices in accordance with agreed protocols. Aside the various benefits IoT provides, it also presents challenges related to security and privacy. The direct connection of IoT devices to the internet makes them susceptible to several security threats. Some ongoing projects for enhancing IoT security include methods for providing data confidentiality and authentication, access control within the IoT network, privacy and trust among users and things, and the enforcement of security and privacy policies. However, even with these mechanisms, IoT networks are vulnerable to multiple attacks aimed to disrupt the network. For this reason, another line of defense, designed for detecting attackers is needed. Intrusion Detection Systems (IDSs) fulfill this purpose. Previous resarch works propose IDSs in relation to IPv6 over Low-power Wireless Personal Area Network (6LoWPAN). However, since IoT will be used in many application domains with different technologies (WiFi, BLE, NFC and Z-Wave), development of IDSs only for 6LoWPAN is insufficient to meet the security needs of every IoT system. This research work focuses on IDSs for IoT devices that use WiFi technology. No previous works address IDSs for IoT devices that use WiFi technology. The research proposes lightweight intrusion detection algorithms that addresses ManIn-The-Middle (MITM) and Rogue Access Points (RAP) attacks. It goes further to propose an orchestration framework for IoT devices which can be used to logically isolate these devices in instances where vulnerabilities are found on them.
Access to water and financial implications of groundwater development in Dodowa, Ghana.
(May 2016) Adjei, Seth Allabo
Global urban population growth has led to an increase in the difficulties in urban water provision. This population growth and urbanization which is rampant in the Sub- Saharan Africa has led to the rapid expansion of slums and informal settlements in the urban centers. Access to drinking water in these urban informal settlements of developing countries has being a challenge. The use of groundwater has hence evolved as a major source of urban water supply. In Ghana, Dodowa is one of the peri-urban communities where groundwater is widely used in addition to utility supplies and hence the research in Dodowa gives a true picture of water supply situation and domestic groundwater use within the urban poor. This study therefore focused on determining access to water supply, its cost implication to consumers and also to assess the financial implications of groundwater development in Dodowa. The methodology adopted was household surveys where a total of 300 households were interviewed to access all the necessary data such as socio-economic status of the consumers, access to water, cost and consumption. In addition, water point inventory was conducted where financial data such as capital cost, operation and maintenance cost and replacement costs of various water points was obtained. The results revealed a variety of water points in Dodowa which include utility pipe public taps, utility piped into buildings, motorized boreholes, hand/foot pump boreholes, hand-dug wells, water tankers and vendors. It was found that groundwater is widely used than all other sources of water supply in Dodowa. As much as 78% of all households use groundwater; only that most consumers of the groundwater sources find the water to be salty and hence they do not patronize it as a main source of supply. The financial analysis revealed that managing a utility public tap as well as motorized borehole fetches good returns with short payback periods (1 year 9 months and 2 years, 3 months respectively) and hence was found to be a profitable business for private water point operators. It was also found that the lowest income group rather pays more for water (0.84 Ghana Cedis/Capita/Day) while the highest income earning group pays less (0.36 Ghana Cedis/Capita/Day). Sachet water was also found to be in high demand (96.3% of all households purchase and use it) and a major contributor to high household water expenditure (it forms 72% of the average household water expenditure).
Adaptive Congestion Control Protocol in Wireless Sensor Networks
(2013-05-04) Dake, Delali Kwasi
in Wireless Sensor Networks (WSN) when an event is detected in an increase in data traffic that might lead to network instability and sensor nodes close to the burst traffic region enters crises state and become congested...
Administration of local community forest rights in the high forest zone of Ghana: The case of forest fringe communities in Tano-Offin forest reserve, Ashanti Region
(2015-07-12) Awuah, Edward Ian
Forest rights and how they are administered constitute a major cause of deforestation and forest degradation. This study examined the administration of statutory local forest community rights against the expectation of forest fringe communities in the high forest zone of Ghana. The study was carried out in the Tano-Offin Forest Reserve in Ashanti Region, a hot spot of deforestation and degradation in the forest zone. A case study approach with qualitative and quantitative data collection methods and analysis was applied. Data was analyzed using SPSS. Eight categories of forest uses and benefits were identified showing substantial and varied uses of the forest reserve by the local people, but they have limited knowledge of the statutory forest rights and access protocols. Overall, 40% to 55% accessed forest uses and benefits across the regimes but as fewer as 19% to 30% were aware of community rights. Yet more people were aware of forest rules (42% to 56%), community responsibilities (23% to 32%) and procedures (22% to 31%) than rights. The people depended on their forebears, government/FC and community for knowledge of forest rights and access protocols. Across the regimes 1% to 9% cited their forebears, 6% to 42% the government/FC and 19% to 39% the community. Only in the Plantation regime that because of MTS forestland cultivation that the people most frequently cited the government/FC otherwise the community was most cited across the regimes. Thus in the absence of a structured awareness creation and education by the FC, knowledge passed on from the forebears and the community has shaped people‟s perceptions and attitudes. The people‟s potentials for collaborative forest management are not fully tapped as they lack formal forest management responsibilities in many respects. To them, the FC is insensitive to their concerns as it pursues forest management principles that exclude their course. They suggested that education on forest rights, improvements in access to forest resources and pragmatic participatory management regime will enhance sustainable management of the reserve. The study recommends a realignment of FC‟s collaborative management to include a pragmatic programme of education on local forest rights and prioritization of local socio-economic aspirations.
The adoption of building information modeling (BIM) in project management in Ghana
(NOVEMBER, 2019) Anim–Wiredu, Solomon;
Building Information Modeling (BIM) was developed in an effort to improve the coordination between disciplines in the construction sector. The Ghanaian Architecture, Engineering and Construction (AEC) industry has started adopting BIM in projects but at a low level. Considering the role project management practitioners play in the success of projects, this study sought to investigate the adoption of BIM in project management in the AEC sector mainly in the Ashanti region in Ghana. Specifically, the study sought to determine the level of knowledge and expertise of project management practitioners in BIM, identify the project management knowledge areas for which BIM is employed and determine the barriers that affect the adoption of BIM in project management activities. Using a questionnaire as the survey instrument, relevant data was obtained from twentythree project management practitioners through purposive sampling and statistically analyzed. The results of the study showed that level of knowledge and expertise of project management practitioners in BIM were averagely low even though most of the experts were aware of BIM. Also, although current BIM usage was relatively low, it was realized that overall, BIM application in project management activities was perceived to be useful in project management knowledge areas especially in Project Integration Management (PIM), Project Scope Management (PScM), Project Cost Management (PCoM), Project Schedule Management (PShM) and Project Quality Management (PQM). Moreover, the study further determined that the reluctance of project management practitioners to change their old working practices, the lack of trained professionals and the cost of procuring BIM technology were the top three barriers that affected the adoption of BIM in project management in the AEC industry. In the recommendation, project management practitioners were therefore encouraged to embrace new technology, find cost-effective and innovative ways of procuring BIM technology and finally engage in formal training in order to improve the adoption of BIM in the Ghanaian AEC sector
Aflatoxin contamination of maize from different storage locations in Ghana
(2008-08-09) Akrobortu, Dick Emmanuel
The contamination of maize by aflatoxins in Ghana is of major concern because of the health hazards associated with it. This study focused on the role played by variations in climatic factors such as relative humidity and rainfall on aflatoxin contamination of maize in different maize storage locations. The study was carried out on samples collected over a period of 10 years (1990 to 1999) in three Districts (Ejura-Sekyedumase, Afram Plains/North-Kwahu and Nkoranza) well – known for maize production in Ghana. The aim was to study the influence of storage locations on levels of aflatoxin contamination and distribution in maize. The findings indicated that significant difference exists between the aflatoxin contamination levels of samples collected from Ejura-Sekyedumase and Nkoranza (p<0.05). Also there was a significant difference between the aflatoxin contamination levels of samples collected from Ejura-Sekyedumase and North-Kwahu (p<0.05). There was no significant difference between the contamination levels of samples from North- Kwahu and Nkoranza (p>0.05). The total aflatoxin levels in samples from Ejura-Sekyedumase, North-Kwahu and Nkoranza over the period were 120.50 ppb, 153.20 ppb and 134.17 ppb respectively. For the period 1990 to 1999 the aflatoxin distributions in the storage locations showed that Nkoranza had the highest level in 1997 and 1999 while North-Kwahu had the highest in 1990, 1991, 1993 and 1998. Similarly, Nkoranza and North-Kwahu had equal levels of 10.50 ppb in 1995. The three locations had equal levels of 9.50 ppb in 1994. On the whole, Ejura-Sekyedumase had fair distribution levels since it was the only location with its highest level far below the acceptable level of 20 ppb for humans. I hereby recommend that further research must be conducted in other districts in the country in order to create awareness of the health hazards associated with the aflatoxin contamination.
Ambient air quality and the health of communities around Chirano Gold Mines Limited
(2011) Ntim, Michael
In communities where mining operations take place there are lot of environmental problems that comes with their processes. One of the greatly affected parts is ambient air quality. This studies aims at investigating the pollution status of the ambient air and the state of health of the communities living within its catchments. With the vitalograph, lung function tests namely; Forced Vital Capacity, Forced Expiratory Volume in 1 sec., Peak Expiratory Flow and Forced Expiratory Flow were performed on inhabitants of Paboase and Akoti communities in the concession of the Chirano Gold Mines Limited. The PM10 and Total Suspended Particles (TSP) in the ambient air were also monitored for a period of 8 months at 7 sampling stations. Results show that the mean PM10 level (64.04 μgm-3) was below the EPA- Ghana standard (70 μgm-3) but above the WHO standard (50 μgm-3). Also the levels of PM10 were below these standards except at all sampling stations except at the Rom Pad (166.72 μgm-3) possibly due to the crushing of rocks and its feeding into the processing plant causing greater liberation of particulate matter into the atmosphere. Mean TSP level (138.93 μgm-3) was also below both the EPA- Ghana standard (230 μgm-3) and WHO standard (200 μgm-3). For similar reasons, higher levels (367.62 μgm-3) than the standards were recorded at the Rom Pad. There was a statistical difference (p<0.00) between the predicted and the measured ling functions suggesting that the ambient air is not polluted and hence, there are health effects associated with the prevailing ambient air quality.
An Approach To Selectively Block Mobile Phone Communication Within A Mobile Phone Restricted Area
(KNUST, 2019-06) Michael Agyare
Abstract The use of mobile phone jammers to discourage mobile phone usage in mobile phone restricted areas has some limitations. One major limitation is that, once the jammer is activated no mobile phone can be able to function within the restricted area. For that reason, in the case of emergencies, no mobile phone can either make or receive phone calls or perform emergency calls (police, fire and ambulance services). Works done in literature can detect and block phone calls in a certain way but depends on the mobile switching centre in order to block communication in the restricted area. Therefore, in this thesis, a selective mobile phone communication blocking system is proposed which does not depend on the mobile switching centre in order to perform blocking of communication. The proposed system seeks to allow privilege users access to communication and block non-privilege users with respect to a specific user location. Some mobile phone user locations were considered in this thesis (Hospitals, Banks and Schools). A user from a particular user location cannot enjoy the same privileges at a different location provided that user is privileged. The selective blocking nature of the system was simulated using Fuzzy Inference System (FIS) toolbox (mamdani). The inference method is based on a set of IF-THEN rules and membership functions of the input variable and output variables of the system. Users for the different locations were converted into input triangular membership functions. The output is the decision (“allow” and “not allow”) for each of the inputs. S-shape and Z-shape membership functions were used as the output decision variables. The set of IF-THEN rules were used to link the input variables to the output variables. The fuzzy inference system was able to perform selective blocking of communication services for privileged and non-privileged users. The results in this work shows that when the proposed system is implemented mobile phone communication service can be prioritised to suit privilege users in specific mobile phone restricted areas.
Anaerobic Co-Digestion of Faecal Sludge with paper or Fruit Waste for Biogas a case in Kumasi, Ghana
(NOVEMBER, 2019) Amenyeku, Gloria;
Increasing attention is being given to biogas generation through anaerobic digestion (AD) all over the world due to concerns over global warming, security of energy and the need for sustainable waste management. Very few areas in Ghana are sewered, the situation is no different in Kumasi where most of the people rely on onsite sanitation systems. Faecal sludge removed periodically from these sanitation systems is further treated in waste stabilization ponds at the Oti treatment facility. However, increasing population and thus increasing volume of sludge being brought to the facility has led to operational difficulties of the facility. This study therefore sought to assess the feasibility of using anaerobic co digestion (AcoD) as an alternative means of treating the faecal sludge brought to the treatment facility before discharging into the environment. By analysing the pH, TS, VS, COD, TP, TKN and helminth eggs according to standard protocols, the physicochemical and microbiological properties of the sludge were investigated. COD: TKN ratios were calculated to assess the suitability of the sludge for anaerobic digestion. Laboratory scale batch AD tests were performed both at mesophilic (35oC) and ambient conditions (24-32oC) to assess the biogas production, the impact of the two temperatures on the treatment, and the effect of sludge retention times on biogas production and sludge stabilization. The efficiencies of the treatment processes were then assessed by computing the percentage removal of TKN and COD from the sludge. Anaerobic co digestion with paper and fruit waste enhanced the faecal sludge characteristics and improved effluent characteristics. The faecal sludge brought to the treatment facility during the period of this study had the following characteristics: pH of 7.02 ±0.2, VS of 65.75 ± 10.98 as %TS, COD of 23050 ± 681.50 mg/L, MC of 98.57 ± 0.84%, TKN of 2842 ± 1094.53 mg/L, and COD: TKN of 8.11. Statistical analysis suggested difference (p-value of 0.003) in the biogas yields under the two temperature regimes however further analysis indicated that the difference was only in the first week. The digesters were filled with faecal sludge and paper or fruit waste in the ratio 1: 0.13. The results obtained in this study showed a total biogas production and weekly methane yield as percentage by volume for Inoculum (I) only, faecal sludge and inoculum (FI), faecal sludge plus inoculum and paper (FIP) and faecal sludge plus inoculum and fruit waste (FIFW) to be 635 (10 – 16.5%), 830 (18.9 – 23.7%), 1355 (16.5 – 47.05%) and 1760 (26.1 – 39.75%) ml respectively under mesophilic temperature and 1085 (0 – 15.5%), 1110 (3.8 – 17.7%), 1515 (14.3 – 41.1%) and 1875 (19.5 – 45.7%) ml respectively under ambient temperature. Effluent characteristics were better in the 4th week for all the digesters indicating that longer sludge retention times has a positive impact on anaerobic digestion.
Analysis And Detection Of Traffic From DOS Attack Tools Using Data Mining
(KNUST, 2019-10) Seth Djanie Kotey
There has been a significant increase in the use of the internet over the past 20 years. As of June 2019, it was estimated that the number of internet users worldwide was over 4.4 billion, corresponding to about 57% of the world’s population. The increase in the use and dependability of the internet has left in its trail a wide variety of vulnerabilities to defend against. One of the key security concepts that helps to guide cybersecurity policies is availability. In a computer network, a denial of service prevents users from having access to resources or services over the network. Denial of service (DoS) attacks are attacks purposely to disrupt availability of a network infrastructure. In past years, a DoS attack required a lot of skill and knowledge in networking for an attack to be launched. However, in recent years, DoS attack tools have been developed by various individuals and groups of people and are readily available on the internet for free or for a little amount of money. Such tools can be used by even the least skilled or knowledgeable attacker. This research therefore sought to develop a defence mechanism against these easy-to-use tools. Attack traffic was captured from some DoS tools and compared with benign traffic. Based on the differences between the attack traffic and benign traffic captured, a signature-based detection algorithm based on support vector machine (SVM) classifier was proposed. The algorithm was tested using the Snort IDS tool and the results were compared with some existing DoS defence schemes. Tests results from the algorithm showed the proposed defence mechanism had a high detection accuracy, low false positive rate and fast detection time.
Analysis of electrical power usage in houses using smart electrical distribution switch.
(October, 2016) Fofie, Kofi
There is high demand for electrical energy because electrical energy is very important in both industrial and domestic activities and that has call for the introduction of different energy meters by various electricity companies. In Ghana families living in large and compound houses wish to have separate energy meters from other occupants. This is because individual’s cannot monitor and control the energy consumption of each individual and that brings misunderstanding in energy bill sharing which also brings about a household having about ten energy meters causing overcrowding of energy meters on the wall of a building which makes the wall loses its beauty and there is likelihood of fire outbreak in the house because the wires are not well arranged. Moreover, energy companies need huge sum of money and labour to produce more energy meters and this can cause financial loss to the energy companies. This has therefore call for the introduction of smart distribution switch which will enhance the monitoring and adequate sharing of energy purchased by the household base on the amount paid by each of the users of the meter. The amount paid will be entered into the system that will be stored on EPROM of a microcontroller that will reduce each consumer’s energy base on the rate of consumption. The smart distribution switch may have different switches allocated to each user which monitor the consumption rate of each user. It will then isolate the user connected to a line out when he /she completely consumes his share.
Analysis Of Lumbosacral Angle, Bio-Data And Their Relationship With Low Back Pain
(KNUST, 2019-11) Opoku, Evelyn
Many researchers believe that lumbosacral angle is one parameter that is of importance in evaluating the possible etiology of lower or low back pain syndrome. There is paucity of data on the lumbosacral angle of the lumbosacral spine in Ghana and other African countries. Most of the data in use in research and medical practice are based on other races but there are anthropometric differences in races. Therefore, the study sought to bring out an empirical data on the pattern of low back pain (LBP) in relation to Lumbosacral Angle (LSA) in our study population and also investigate the association between LBP, LSA, age, gender and weight. Lateral views of the lumbosacral spine radiographs of 177 Ghanaian subjects from the St. John of God Hospital at Duayaw-Nkwanta were studied. The demographics and anthropometric measurements of the subjects such as age, gender and weight were recorded. The LSA was measured using the Ferguson‟s orthogonal method with the Micro Dicom Viewer software. The researcher employed the descriptive as well as the regressional survey. The findings from the study indicated that the population were dominated by females who constituted 70.1% of the study population as against males who also constituted 29.9%. In terms of age, majority of the participants were between the ages of 40 to 59 years as against the least that were between the ages of 0 to 19 years. The results showed that 41.8% of the sample did not have low back pain as against 58.2% who had low back pain. The mean LSA value for the normal controls was 14.5º with SD ± 1.32º. This can value can be recognised as the normal LSA for our population in from the study. A positive significant relationship was established between LSA and Low Back Pain. This simply means that an increase in LSA leads to 2.5 % increase in probability or risk of low back pain. Findings from the study showed that an increase in age leads to 41.8 % increase in the probability of having low back pain. Weight was found to positively correlate to low back pain. An increase in weight leads to 1.6% increase in the probable result of low back pain. This relationship was predicted to be significant. The study showed that there is a positive and significant relationship between LSA, age, weight and low back pain. The probability of pain of the lower back among males was also found to be 33.1% less than the probability that will be incurred by females and it is also not a significant relationship. In conclusion the mean angle values and variables may form the reference values for the Ghanaian population.
Analysis of Lumbosacral Angle, Bio-Data and their relationship with low back pain
(NOVEMBER, 2019 ) Opoku, Evelyn;
Many researchers believe that lumbosacral angle is one parameter that is of importance in evaluating the possible etiology of lower or low back pain syndrome. There is paucity of data on the lumbosacral angle of the lumbosacral spine in Ghana and other African countries. Most of the data in use in research and medical practice are based on other races but there are anthropometric differences in races. Therefore, the study sought to bring out an empirical data on the pattern of low back pain (LBP) in relation to Lumbosacral Angle (LSA) in our study population and also investigate the association between LBP, LSA, age, gender and weight. Lateral views of the lumbosacral spine radiographs of 177 Ghanaian subjects from the St. John of God Hospital at Duayaw-Nkwanta were studied. The demographics and anthropometric measurements of the subjects such as age, gender and weight were recorded. The LSA was measured using the Ferguson’s orthogonal method with the Micro Dicom Viewer software. The researcher employed the descriptive as well as the regressional survey. The findings from the study indicated that the population were dominated by females who constituted 70.1% of the study population as against males who also constituted 29.9%. In terms of age, majority of the participants were between the ages of 40 to 59 years as against the least that were between the ages of 0 to 19 years. The results showed that 41.8% of the sample did not have low back pain as against 58.2% who had low back pain. The mean LSA value for the normal controls was 14.5º with SD ± 1.32º. This can value can be recognised as the normal LSA for our population in from the study. A positive significant relationship was established between LSA and Low Back Pain. This simply means that an increase in LSA leads to 2.5 % increase in probability or risk of low back pain. Findings from the study showed that an increase in age leads to 41.8 % increase in the probability of having low back pain. Weight was found to positively correlate to low back pain. An increase in weight leads to 1.6% increase in the probable result of low back pain. This relationship was predicted to be significant. The study showed that there is a positive and significant relationship between LSA, age, weight and low back pain. The probability of pain of the lower back among males was also found to be 33.1% less than the probability that will be incurred by females and it is also not a significant relationship. In conclusion the mean angle values and variables may form the reference values for the Ghanaian population.
Analysis of mimo antenna configuration effects on Wimax Network deployment in Ghana
(2015-07-11) Tutu Tchao, Eric
Worldwide Interoperability for Microwave Access (WiMAX) technology has gained growing interest due to its applications and advantages. It is fast emerging as a last-mile problem solution for broadband access technology. This thesis presents operational scenarios for the deployment of a Fourth Generation (4G) WiMAX system in a typical Sub-Saharan African environment. The work in this research has been specified based on real world conditions considering the regulatory rules stipulated by the National Communication Authority for radio frequency spectrum utilization in the 2.6GHz licensed band in Ghana. Appropriate propagation models and network planning tools have been used to design the optimized final radio network plan for the various Multi-Input Multi- Output (MIMO) configurations. A parameter called Interference to Noise Ratio (INR) was introduced to optimize the BER performance of the deployed 2x2 MIMO configuration in the presence of multiple interferers. The INR parameter was used to fit the BER results and then subsequently optimize the 2x2 MIMO configuration performance in the striped case to create a wide virtual bandwidth. The fitting INR parameter helped to improve the BER performance once the threshold INR was exceeded. This result extends the principle of successive decoding to MIMO systems affected by partial band interference under the assumption of a common receive correlation matrix. Unsuppressed sidelobe emissions also distort the performance of MIMO antenna systems used in deploying multicarrier networks. In order to accurately evaluate the performance of the MIMO antenna configurations used in the network deployment scenario, a mathematical model for estimating the effective beamwidth and sidelobe suppression factors for MIMO antenna systems used in multicarrier deployment scenarios was developed. The derived step function can be used to minimize the effect of antenna sidelobe emission in a realistic iii deployment scenario and also as an operational guideline tool to model added isolation factors. This function may provide a means to determine practical antenna sidelobe suppression factors in subsequent WiMAX deployments. Coverage, capacity, and interference predictions have been performed using MATLAB, 4-NEC 2 and Genex-U-Net for the predefined areas of Accra and Tema, Ghana. Simulation results for different downlink/uplink ratios with different frequency reuse schemes and antenna configurations have been presented. A total of 11 base stations have been suggested to provide coverage of -92dBm using 32 sectors adaptive 4x4 MIMO antenna configuration to provide a 3dB gain over the deployed adaptive 2x2 MIMO system thereby reducing deployment cost. Finally, based on the high system performance of the evaluated network, secure communication models and network architectures have been proposed in three case study areas. Keywords: Performance Evaluation; Capacity Simulation; Interference Modeling; WiMAX Radio Planning; Successive Cancellation Technique.
Analysis of surface interpolation algorithms for different surface types
(2017-01-31) Agyei, Safo Kofi
Digital Terrain Models (DTMs) has become a very significant tool in extracting geomorphological information from various land areas. Their use is in the fields of mapping, landscape planning, urban design and many more. Automatic stereocorrelation has been used to generate a DTM from ASTER stereo image pair (3N and 3B) using ENVI software. Elevation values were extracted and used with four different interpolation algorithms. The resulting surfaces when compared with those from the topographic map showed that the Inverse Distance Weighting (IDW) can achieve a Root Mean Square Error (RMSE) of ±10.773m and Mean Absolute Error (MAE) of ±8.714m for flat terrain as compared to RMSE of ±11.035m, MAE of ±8.999m for spline; RMSE of ±11.121m, MAE of ±9.102m for Natural Neighbour (NN) and RMSE of ±12.108m, MAE of ±9.979m for kriging interpolation method using a point density of 61.49 points per km 2 . Hence, IDW is best for this surface type. For undulating terrain, IDW again gave the least RMSE of ±13.549m and MAE of ±10.789m in comparison to RMSE of ±13.711m, MAE of ±10.963m for NN; RMSE of ±13.717m, MAE of ±11.028m for spline and RMSE of ±14.835m, MAE of ±11.658m for kriging interpolation method for point density 62.30 points per km 2 and hence, IDW is again best for this surface type. For mountainous terrain, NN interpolation method with RMSE of ±19.044m and MAE of ±13.909m gave best results than the other interpolation types. RMSE of ±21.167m, MAE of ±15.241m was obtained for kriging; RMSE of ±21.632, MAE of ±14.687m for IDW and RMSE of ±21.721m, MAE of ±14.544m for spline for point density 141.64 points per km 2 and so NN works best for mountainous terrains. It is therefore recommended that IDW interpolation algorithm should be used for both flat and undulating terrains whereas NN should also be used for mountainous terrains.
Analysis of technical and financial benefits of energy efficient practices in selected Electricity Company of Ghana (ECG) buildings in Accra
(MAY, 2016 ) Quaye-larbi, Hesford
Energy is a critical resource for human development. However, for many people, the option to conserve energy by using energy efficient appliances and machines and proper maintenance culture is not practiced. Research has shown that the total energy use of a building can be reduced by implementing energy efficient design strategies at the design stage of a building. Passive energy efficient design techniques like proper building orientation, use of sun shading, selection of materials more suitable to prevailing climatic conditions can considerably reduce a building’s energy use and reflect in economic gains to all stakeholders. The present study set out to analyse and outline the technical and financial benefits of energy efficient practices in Electricity Company of Ghana buildings in Accra. A case study of the two regional buildings (Accra East and Accra West) was conducted in order to compare their energy efficiency profiles. Data collected from comprehensive energy audits formed the basis of the projections. A reliable and previously validated, standardized Energy Audit Tool complete with an operating manual was used to make study findings readily comparable and verifiable. The mean total energy consumption for Accra West was 414,077kWh while that for Accra East was 659,477 kWh. Accra East consumed approximately 150% of energy compared to Accra West. Over the period, the mean occupancy-adjusted energy consumption for Accra West and Accra East was 1,648 and 2688 kWh/person respectively. The present data shows that the energy efficient practices in place at the Accra West building is able to save on the average 1040 kWh/person every year. At the current rate of GHȻ0.4712 , this translates to a cost benefit ofGHȻ 490.048 (0.4712 X 1040) per person per year for the Accra West building. For a total staff roster of 245 workers, therefore the point can indeed be made that the Accra West facility accrues a financial gain of GHȻ 120,061.76 (490.05 X 245) per year. We conclude that the Accra West regional office of the Electricity Company of Ghana iii performs better as a model energy efficient building than the Accra East regional office building and could be emulated.
Applicability of clay pozzolana in hydraulic backfilling of stopes at the AngloGold Ashanti, Obuasi mine
(2015-02-23) Eshun, Samuel Nana
The quest for a cheaper alternative or supplement to ordinary Portland cement as binder in the backfilling of mined out stopes in underground mines motivated this study. Clay pozzolana has been proven to substitute about 30% of Portland cement in general construction works and is cheaper. However, very little is known about its applicability in mine backfill. This study therefore sought to investigate whether clay pozzolana could be applied in the case of hydraulic backfill in the AngloGold Ashanti, Obuasi Mine. Samples of the classified tailings from the AngloGold Ashanti, Obuasi Mine were prepared with different amounts of ordinary Portland cement and clay pozzolana combinations into 50mm diameter by 120mm high cylindrical specimens and then tested for compressive strength after curing under humid conditions for various periods. Samples of the tailings were also subjected to particle size distribution and sulphate content analyses. The results indicated that generally, backfill with 10%, 25%, 30% and 35% of the ordinary Portland cement content replaced with clay pozzolana had strength values comparable to those obtained for samples containing ordinary Portland cement alone. Ten per cent (10%) pozzolana content replacement showed consistent maximum strength characteristics after curing beyond 7 days. Therefore, in terms of strength; it is recommended that 10% of ordinary Portland cement could be substituted with clay pozzolana in the hydraulic backfilling of voids in the AngloGold Ashanti, Obuasi Mine. The particle size distribution analysis indicated that the tailings are suitable in terms of its drainage characteristics for hydraulic backfilling of voids. The results of the sulphate content analysis indicated that the sulphate content of the tailings obtained from AGA, Obuasi Mine for the study was higher compared with the upper limit set by ASTM Standard C94 and European iv Standard EN 1008.Using 2013 as the baseline, an amount of Gh¢12.00 would be saved on every tonnage of cement used. This represents 3% of the amount of money spent on every tonnage of cement used.
Application of magnetic and electrical geophysical methods in delineating auriferous structures in the Sefwi belt of Ghana
(OCTOBER, 2016 ) Majeed, Fareed
Gold is a very important economic commodity to the growth of Ghana‟s development. The prospecting and exploration stages of mining involve long periods of investment with a high risk of failure. Even before strenuous effort is put into the discovery of reserves, many exploration companies become cash-strapped to the extent of collapse and may find near mine development very challenging. For this reason prospecting for gold needs to be optimized and that calls to mind the attention of choosing the right techniques that will enhance the success of the exploration projects. Four indicative spatial features -shear (ductile) zones, favorable host rock units with fracture arrays, hydrothermal alterations and strongly deformed (brittle) or faults zone- were the driven force behind this research. Two geophysical methods namely ground magnetic and electrical tools were integrated with existing geological dataset to map out structures in the Sefwi belt of Southern Ghana. The magnetic data obtained were processed into grids with Geosoft. Data enhancement filters such as reduction to the pole, tilt-angle derivative, first and second vertical derivatives and continuation filters were further applied to Total Magnetic Intensity (TMI) grid to enhance magnetic anomalies. The induced polarization-chargeability data were measured in the time domain. The positive anomalies on the IP-chargeability map coincided with the shears margins alterations and contact zones. Two dipole–dipole sections were carried out in the study area and were inverted using the RES2DINV program. From the results obtained, an interpreted definitive geologic map of the study area consisting of the geology, structures and hydrothermally altered zones were produced with MapInfo (Discover). All recognizable features were mapped as major and inferred thrust fault, lineation and alteration. The result is a preliminary mineral potential map...
Application of Neural Network in Financial Market
(2011) Amoako, Prince Yaw Owusu
To be successful in a competitive world, any organization must not only maintain a good understanding of the current conditions, but be able to forecast the future as accurately and precisely as possible. Analysis of historical trends in data, with a view to making predictions is therefore a key task, and one for which neural network technology is well suited. In general, application of neural network in financial market is discussed. Specifically, the prediction of foreign exchange rate using neural network called “feedforward” neural network with one hidden layer consisting of three neurons is considered in deriving the model for the forecasting. Statistical evaluation of the output from the implementation of the neural network model on the forecast values with the actual of Banks-Indicative Opening U.S. Dollar, Pound Sterling and Euro Rates – Selling, are discussed. Further comparison of the results obtained from the improved model and the existing model was considered. The results obtained suggest that neural network model produces better accurate predictions than other time series forecasting models. The use of the system in financial market and specifically on the prediction of exchange rates typically involves the utilization of other financial indicators and domain knowledge since real life data were used as input.

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