KNUSTSpace

Institutional Repository of the Kwame Nkrumah University of Science and Technology

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Recent Submissions

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A Multi-objective Optimization Approach to Workflow Scheduling in Clouds Considering Fault Recovery
(Korean Society for Internet Information, 2016-03) Xu, Heyang; Yang, Bo; Qi, Weiwei; Ahene, Emmanuel; 0000-0002-0810-1055
Workflow scheduling is one of the challenging problems in cloud computing, especially when service reliability is considered. To improve cloud service reliability, fault tolerance techniques such as fault recovery can be employed. Practically, fault recovery has impact on the performance of workflow scheduling. Such impact deserves detailed research. Only few research works on workflow scheduling consider fault recovery and its impact. In this paper, we investigate the problem of workflow scheduling in clouds, considering the probability that cloud resources may fail during execution. We formulate this problem as a multi-objective optimization model. The first optimization objective is to minimize the overall completion time and the second one is to minimize the overall execution cost. Based on the proposed optimization model, we develop a heuristic-based algorithm called Min-min based time and cost tradeoff (MTCT). We perform extensive simulations with four different real world scientific workflows to verify the validity of the proposed model and evaluate the performance of our algorithm. The results show that, as expected, fault recovery has significant impact on the two performance criteria, and the proposed MTCT algorithm is useful for real life workflow scheduling when both of the two optimization objectives are considered
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A blockchain-based certificateless public key signature scheme for vehicle-to-infrastructure communication in VANETs
(Journal of Systems Architecture, 2019-10) Ali, Ikram; Gervais, Mwitende; Ahene, Emmanuel; Li, Fagen; 0000-0002-2893-4249; 0000-0002-0810-1055
Vehicular Ad Hoc Networks (VANETs) have been developing based on the state-of-art in wireless network communication technologies to improve traffic on roads. However, there are some threats to security and privacy due to the open wireless environment in VANETs and the high speed of vehicles. The uthentication of messages related to traffic which are exchanged with the vehicles and the Road-Side Unit (RSU) is considered one of the most VANETs necessary security requirements. In this context, several schemes have been designed to secure the traffic-related messages in VANETs. However, these schemes suffer from high computational costs in signatures’ verification. To minimize the computational cost of signature generation and verification, we propose an efficient Certificateless Public Key Signature (CL-PKS) scheme using bilinear pairing to provide conditional privacy-preserving authentication for Vehicle-To-Infrastructure (V2I) communication in VANETs. The CL-PKS scheme supports batch signature verification and aggregate signature verification functions to speed up verification process. In addition to this, we include blockchain to our CL-PKS scheme to implement revocation transparency of pseudo-identities efficiently before verifying the signatures. Furthermore, this scheme provides security proof and protection against different types of attacks. The proposed scheme incurs lower computational cost as compared to that incurred by existing schemes.
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Hydro-ethanol extract of Holarrhena foribunda stem bark exhibits anti-anaphylactic and anti-oedematogenic efects in murine models of acute infammation
(BMC Complementary Medicine and Therapies, 2022-03-19) Antwi, Stephen; Oduro‑Mensah, Daniel; Darko Obiri, David; Osafo, Newman; Opoku Antwi, Aaron; Owusu Ansah, Helena; Ocloo, Augustine; Okine, Laud K. N.‑A.
Background: Holarrhena foribunda (G.Don) T.Durand & Schinz stem bark has anecdotal use in Ghanaian folk medi‑ cine for the management of infammatory conditions. This study was conducted to investigate the in vivo anti-infam‑ matory activity of the bark extract using models of acute infammation in male Sprague Dawley rats, C57BL/6 mice and ICR mice. Methods: A 70% hydro-ethanol extract of the stem bark (HFE) was evaluated at doses of 5–500 mg/kg bw. Local ana‑ phylaxis was modelled by the pinnal cutaneous anaphylactic test. Systemic anaphylaxis or sepsis were modeled by compound 48/80 or lipopolysaccharide, respectively. Clonidine-induced catalepsy was used to investigate the efect on histamine signaling. Anti-oedematogenic efect was assessed by induction with carrageenan. Efects on mediators of biphasic acute infammation were studied using histamine and serotonin (early phase) or prostaglandin E2 (late phase). Results: HFE demonstrated anti-infammatory and/or anti-oedematogenic activity comparable to standard doses of aspirin and diclofenac (inhibitors of cyclooxygenases-1 and -2), chlorpheniramine (histamine H1-receptor antagonist), dexamethasone (glucocorticoid receptor agonist), granisetron (serotonin receptor antagonist) and sodium cromogly‑ cate (inhibitor of mast cell degranulation). All observed HFE bioactivities increased with dose. Conclusions: The data provide evidence that the extract of H. foribunda stem bark has anti-anaphylactic and antioedematogenic efects; by interfering with signalling or metabolism of histamine, serotonin and prostaglandin E2 which mediate the progression of infammation. The anti-infammatory and antihistaminic activities of HFE may be relevant in the context of the management of COVID-19.
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Rainfall Prediction Using Machine Learning Algorithms for the Various Ecological Zones of Ghana
(IEEE Access, 2022-12) Appiah-Badu, Nana Kofi Ahoi; Missah, Yaw Marfo; Amekudzi, Leonard K.; Ussiph, Najim; Frimpong, Twum; Ahene, Emmanuel; 0000-0002-3029-4498; 0000-0002-2926-681X; 0000-0002-2186-3425; 0000-0002-6973-7495; 0000-0002-1869-7542; 0000-0002-0810-1055
Accurate rainfall prediction has become very complicated in recent times due to climate change and variability. The efficiency of classification algorithms in rainfall prediction has flourished. The study contributes to using various classification algorithms for rainfall prediction in the different ecological zones of Ghana. The classification algorithms include Decision Tree (DT), Random Forest (RF), Multilayer Perceptron (MLP), Extreme Gradient Boosting (XGB) and K-Nearest Neighbour (KNN). The dataset, consisting of various climatic attributes, was sourced from the Ghana Meteorological Agency spanning 1980 – 2019. The performance of the classification algorithms was examined based on precision, recall, f1-score, accuracy and execution time with various training and testing data ratios. On all three training and testing ratios: 70:30, 80:20 and 90:10, RF, XGB and MLP performed well, whereas KNN performed least across all zones. In terms of the execution time of the models, Decision Tree is consistently portrayed as the fastest, whereas MLP used the most run time.
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Aurantio-obtusin alleviates allergic responses in ovalbumin-induced rhinitis
(Scientific African, Elsevier, 2023-11-30) Nyarko, Mavis Sersah; Danquah, Cynthia Amaning; Antwi, Aaron Opoku
Allergic rhinitis (AR) is a growing global health concern. Despite being non-fatal, it has a detrimental effect on people’s quality of life and poses a significant economic burden. In this study, we aimed to evaluate the anti-allergic effects of aurantio-obtusin against ovalbumin-induced murine model of allergic rhinitis. Aurantio-obtusin was administered to rats orally after sensitization to ovalbumin. Results of the study suggested that aurantio-obtusin causes a significant reduction in nose rubs and sneeze as compared to the vehicle-treated disease control group. The aurantioobtusin treated group showed a dose-dependent significant reduction in serum TNF-α, IL-4, and IL-6 levels as well as histamine levels in the nasal mucosa. Additionally, it decreased neutrophil and eosinophil numbers in blood of AR rats’. In the nasal tissues of the vehicle-treated rats that were subjected to an OVA challenge, the histology of the nasal mucosa of AR rats revealed aberrant histological changes. A variety of histological abnormalities, including vascular congestion in the nasal mucosa, substantial inflammatory cell infiltration, and obvious alveolar wall oedema were present. In the rats treated with aurantio-obtusin, these characteristics were reversed. Collectively, the findings suggests that aurantio-obtusin could be used to enhance current AR treatment approaches.
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Gender and leadership positions: understanding women’s experiences and challenges in patriarchal societies in Northern Ghana
(International Journal of Sociology and Social Policy, 2023) Adongo, Awinaba Amoah; Dapaah, Jonathan Mensah; Azumah, Francess Dufie; 0000-0002-0261-3295; 0000-0002-9349-6273; 0000-0001-6023-8000
Purpose – Women are rarely seen in positions of leadership in patriarchal societies, which is unsurprising.Following gender equity policies, few women have been able to break through the gender equity barrier and assume leadership positions in schools. Few research investigations have delved into the experiences and challenges that women encounter in positions of leadership in patriarchal societies in government schools in Northern Ghana. The study seeks to comprehend the experiences and challenges that women confront in positions of leadership in patriarchal societies in Northern Ghana. Design/methodology/approach – The study aimed to gain a better understanding of the experiences and challenges that women encounter in educational leadership roles in patriarchal societies in Northern Ghana. To achieve the study’s objectives, a quantitative research approach and a social survey design were used, as well as descriptive and inferential statistics. Findings – The findings of the study revealed that in patriarchal societies in Northern Ghana, women experience conventional gender roles that conflict with roles, cultural values, gender stereotyping, family responsibilities and cultural beliefs and perceptions of women and attitudes and low expectations of women’s managerial skills discourage women from taking on leadership positions in men-dominated societies.
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Building the capacity of students in creative problem-solving and critical thinking skills: Aesthetic narrative of Ayigya Township, Ghana
(Royallite Global, 2023) Kquofi, Steve; Adom, Dickson; https://orcid.org/0000-0001-6263-615X; https://orcid.org/0000-0002-0559-4173
The study set out to investigate the environmental aesthetics present in habitual areas, specifically in Ayigya Township, Ashanti Region, focusing on picture-making tendencies for optimal skill development. A total of 346 respondents from various structures were specifically chosen to participate in the study using the Narrative Case Study Design under the qualitative research approach. Semi-structured interviews, observation, and photographic documentation were used for the data collection. The data were analysed using photographic documentary and qualitative narrative analysis. The findings demonstrated how dispersed aesthetic elements are in everyday life and how this appreciation would have a positive impact on the Senior High School student’s capacity for creative problem-solving and critical thinking skills. It is suggested that students develop alternative means of expressing their creativity. The study contends that art teachers must help students to use aesthetics in their environments to develop the tools and materials for their artistic productions.