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).
Acquisition, prospecting and development of mineral properties in Ghana
(1996) Morna, Bryne Ansin
As a result of the favourable investment climate created by the Government of Ghana, investors have recently been attracted to the mineral industry. However, the pace at which mining concessions are successfully developed is very slow. The main cause has been identified as the difficulty of knowing all the rules governing the acquisition, prospecting and development of mineral properties in the country. The purpose of this thesis is to study and analyze the procedures and problems associated with acquisition, prospecting and development of mineral properties in Ghana and provide possible solutions. A collation of documents and information on mineral property acquisition, prospecting and development in the country has been made and a step-by-step guide for investors provided. Some recommendations have also been made to assist would-be investors in the mineral industry of Ghana.
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...
Adaptive control of alumina concentration in the hall-heroult cell using neural network
(1996) Boadu, Kwaku Debra
Aluminium smelting the world over has had two major constraints in recent years: environmental protection and energy costs. Since the method and efficiency of alumina feed in the smelting process impacts environmental pollution and production efficiency greatly, much of the industry’s investment money has been spent in researching into better feed control systems - feed delivery systems and feed strategies. The subject matter of this thesis dwells on the latter, and continues the search for an efficient adaptive alumina feed strategy in the Hall-Héroult cell for the reduction of aluminium. Neurocomputing, one of the fastest growing control system theories in contemporary electrical engineering, is applied to the problem of on-line estimation of alumina mass balance in the electrolytic cell. A contribution is proposed to alumina feed control strategies by developing a neural network-based adaptive feed control algorithm, robust against cell resistance variations, and implementable on retrofit state-of-the-art aluminium reduction cell microcomputers. Electrolytic resistance/alumina concentration data from a simulated l4OkA Center-Break cell was used as input vectors to train a single-layer feed forward loop-back NEURAL NETWORK1 constructed with six constraint equations and six degrees of freedom. The identified prediction algorithm was successfully tested on both simulated and real cell resistance data and results presented. The algorithm was also compared with the extended Kalman filter using the same test bed and shown to be a better solution to the problem under research. Finally a NEURAL network-based feed control strategy (NetFeed) is developed and presented in this thesis.
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 blasting techniques at Ghana National Manganese Corporation, Nsuta-Wassa, Ghana
(1992) Agbeno, Simon Kwesi
Ghana National Manganese Corporation (GNMC) at Nsuta-Wassa in Ghana produces manganese ores by open—pit technology. The deposits are Pre-Cambrian in age, and are characterised by a series of strong folding and faulting. These rocks are of medium to high strength and have high densities (2.81-3.72 kg/rn3). One of the methods of loosening in situ material for excavation and loading on the mine is by drilling and blasting. Analysis of records from the mine has shown that tonnage produced by blasting constitutes about 38% of total annual production. It has been observed that primary blasts produce coarse fragmentation. The cause of the poor rock fragmentation is improper blasting practice. The poor blast performance explains why unit cost of drilling and blasting constitutes as much as 65% of unit costs of mining. In this research work, the present drilling and blasting practices have been studied. Alternative blast design paramaters have been determined, taking into consideration the geomechanica1 properties of the rocks and the prevailing operational conditions at the mine. These parameters have been field tested. Eventually, an effective blasting technique has been designed to improve the performance of the mine. It has been established that of all the design parameters, including that of the present mine practice, which have been field tested, the technique using a 2.0m by 2.8m drilling pattern produces best results. This technique requires 50-60% less drilling and 30-40% less explosives. When drilling and blasting are considered together as one operation, an overall improvement of 40-50% was achieved over the present mine practice. It is suggested that, to achieve the desired performance from the blasting technique using 2.0m by 2.8m drilling pattern, a stemming length of l.6m is required to provide the necessary explosives confinement. Millisecond delays are also to be used as an integral part of the blasting technique for an improved blast performance.
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 injuries at Ashanti Goldfields Company (AGC) Limited (Obuasi Mine)
(1996) Asongo, George Akuribilla
Over the last decade, mining activities have been springing up in many parts of Ghana due to the growing demand for minerals and the favourable investment climate created by government, to earn more foreign exchange from the mining sector. From history these mining activities have been associated with poor working conditions that result in high cost of production, partly due to injuries from the operations. Ashanti Goldfields Company places emphasis on minimizing injuries in order to increase production level and it is also their aim to follow international standards in assessing safety at work places. This work seeks to study the incidences that result in the various levels of injuries, analyse injury data to determine the accident frequency rates, accident severity rates and to assess the effects of accidents on productivity at AGC, Obuasi mine. From the analysis it was realised that hands and legs were the parts of the body that were mostly injured. Handling however, was the cause of most of the injuries, fall of ground and slip fall also showed high percentages. However, in all the cases there have been improvement as the years go by. The accident frequency rate and that of accident severity rate showed some improvement progressively. There is the need to understand and control injury associated problems in the operations of the mining activities, some of which have been reviewed in this work. This work could serve as a basis in this respect to guide new or other mining companies.
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.
An analysis of productivity and cost efficiency of underground labour at George Capendel Shaft of Ashanti Goldfields Corporation (Ghana) Limited
(1990) Frimpong, Mensah
The treatise analyses the possibilities of increasing productivity at optimum cost. The study revealed that labour motivation at AGC is quite low. Job-centered style of supervision, machine downtime poor environmental conditions and labour unrest are among the factors hindering productivity. Productivity is analysed terms of tons or advance per man-shift. Production efficiency is the ratio of actual to the programmed productivity whereas cost efficiency is the ratio of forecast cost to the actual. The mean actual productivities of the various stopes were; for cut – and – fill (conventional) stopes (2 t/m-s), cut – and – fill (machinised) stopes (2.5 t/m-s), sublevel are 3. t/m-s, 8 t/m-s, 3.2 t/m-s respectively, and 2.5 t/m-s for shrinkage stopes. At development ends, mean productivities were 0.61 feet/man-shift for raises and 0.875 feet/man-shift for lateral development The percent-age contribution of the operating cost of mining by the various cost centers are ; stoping cost (36.56%) , slope preparation cost ( 13. 18%) -. slope development cost (26. 96%) and 2 3% for the working cost.. The study also revealed a decline in performance of AGC in terms of cost from 1980/81 to date.

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