60 research outputs found
The design of a defence mechanism to mitigate the spectrum sensing data falsification attack in cognitive radio ad hoc networks
No full textThesis ( M.Sc. ( Computer Science)) -- University of Limpopo, 2018Dynamic spectrum access enabled by cognitive radio networks is envisioned to address the problems of the ever-increasing wireless technology. This innovative technology increases spectrum utility by allowing unlicensed devices to utilise the unused spectrum band of licenced devices opportunistically. The unlicensed devices referred to as secondary users (SUs) constantly sense the spectrum band to avoid interfering with the transmission of the licenced devices known as primary users (PUs).Due to some environmental challenges that can interfere with effective spectrum sensing, the SUs have to cooperate in sensing the spectrum band. However, cooperative spectrum sensing is susceptible to the spectrum sensing data falsification (SSDF) attack where selfish radios falsify the spectrum reports. Hence, there is a need to design a defence scheme that will defend the SSDF attack and guaranty correct final transmission decision.
In this study, we proposed the integration of the reputation based system and the qout-of-m rule scheme to defend against the SSDF attack. The reputation-based system was used to determine the trustworthiness of the SUs. The q-out-of-m rule scheme where m sensing reports were selected from the ones with good reputation and q was the final decision, which was used to isolate the entire malicious nodes and make the correct final transmission decision. The proposed scheme was implemented in a Cognitive Radio Ad Hoc Network (CRAHN) where the services of a data fusion centre (FC) were not required. The SUs conducted their own data fusion and made their own final transmission decision based on their sensing reports and the sensing reports of their neighbouring nodes. Matlab was used to implement and simulate the proposed scheme. We compared our proposed scheme with the multifusion based distributed spectrum sensing and density based system schemes. Metrics used were the success probability, missed detection probability and false alarm probability. The proposed scheme performed better compared to the other schemes in all the metrics.CSIR,
NRF and,
University of Limpopo research offic
The design of a defence mechanism to mitigate the spectrum sensing data falsification attack in cognitive radio ad hoc networks
No full textTrust-Based System to Defend Against the Spectrum Sensing Data Falsification Attack in Cognitive Radio Ad Hoc Network
No full textManaging Corporate Social Responsibility with Management Control Systems
No full textPurpose- This study aims to explore how management control systems are used to manage their corporate social responsibility strategies in organizations. This paper dives into how sustainability managers use existing controls in planning, executing, measuring, and reporting on their CSR. The challenges they face in implementing their CSR strategies with these control systems are also covered. Methodology- The research was conducted using a qualitative research approach and a multiple case study strategy. The multiple case study involved three companies within a CSR network in Sweden. Secondary data from sustainability reports, internal financial control (IFC) reports were used together with seven semi-structured interviews. Findings- Control systems monitor influence and steer the employee's behavior and actions towards achieving organizational goals. The thesis provides practical insights into how sustainability managers from the studied companies use management control systems. The findings indicate that companies use similar clusters of management controls in planning, executing, measuring and reporting on their corporate social responsibility. However, there are differences in how the same management controls are used. The author identified a different type of control which is mostly not included in discussing when discussing MCS
The Correlation between Aspect and Transitivity Alternation in Dagbani
No full textThis paper attempts to describe and analyze the relation between aspect and transitivity in Dagbani, a Gur language spoken in the Northern Region of Ghana by the Dagbamba. The author does this by focusing on the fact that there are different (perfective and imperfective) aspectual markers that correlate with the presence or absence of NP objects or adjunct phrases, such as adverbs. I conclude that pronouncing any syntactic element after a Dagbani verbal phrase or otherwise is determined by the aspectual suffixes of that verbal phrase.In an attempt to find explanations to this transitivity alternations, I make two hypothesises; the incorporated pronouns hypothesis and the focus hypothesis. None of these however, seems to adequately address the problem and I leave the working out of this to future research. It is shown that the correlation between aspect and transitivity in Dagbani sounds (at least superficially), very similar to the so-called “conjoint/disjoint” or “short/long” verb phenomenon that is found in a number of Bantu languages
Investigation of the upper mantle under Hawaii using PP and SS precursor functions
No full textThe Hawaiian island chain forms a part of the Emperor-Hawaiian chain and is located on the central part of the pacific plate. Current theories support the formation of the island chain by combination hotspot activity and movement of the pacific plate. However, the mechanism behind the formation of the hotspot and its origin have been subject to debate; much like hotspots beneath other known island chains. In this research, we investigate the upper mantle transition zone under the Hawaiian Island chain to give an insight into how the hotspot affects this zone and what that implies for the origin and mechanism of the hotspot supplying volcanism on the Hawaiian island chain. The 410 and 660 discontinuities (referred to simply as 410 and 660) which are recognized as velocity contrasts on seismic images mark the transition zone boundaries and have known reaction to localized anomalous temperatures. The depth to 410 increases and the depth to the 660 decreases in the presence of higher than usual temperature resulting in a thinner transition zone. Colder than usual temperatures would result in a reduction of the depth to the 410 and an increase in the depth to the 660, resulting in a thicker transition zone. These are the characteristics that we leverage to interpret our images.
Taking advantage of the dense bouncepoints in the study area contribute by the US transportable array, we image the area with PP and SS precursor analyses using Wavefield Iterative Deconvolution (WID). Our results are adequately backed by the 3D GyPSuM Earth Model although our images show higher resolution and hence more detail. Our results show are generally shallower than expected 660 over the whole study area indicating a warm anomaly. The 410 shows localized shallow and deep areas indicating the existence of some colder anomalies and warm anomalies. We interpret the generally warm 660 as a result of pooling of magma beneath the 660 due its tendency to resist convection. The magma under the 660 eventually breaks through forming a narrow conduit the rises through the transition zone and 410 all the way to the surface and supplies magma to the Hawaiian hotspot. This would explain why there are localized warm anomalies on the 410 as opposed to the 660. The localized cold anomalies on the 410 can also be explain as the downwelling of cold material in response to the rise of the magma.Embargo status: Restricted to TTU community only. To view, login with your eRaider (top right). Others may request the author grant access exception by clicking on the PDF link to the left
Landscape position, sampling time and tillage, but not legume species, affect labile carbon and nitrogen fractions in a four-year-old rejuvenated grazed pasture
No full textTermination by tillage is one strategy used for regenerating pasture stands. Yet, research gaps exist on how tillage affects carbon (C) and nitrogen (N) forms and amounts in western Canadian soils. We measured total soil organic C (SOC), dissolved organic C (DOC), total dissolved N (TDN), light fraction organic C (LFOC) and N (LFON), microbial biomass C (MBC) and N (MBN), and inorganic N as indicators of soil organic matter (SOM) dynamics. After tillage termination in fall 2018, we sampled soils (0‒10cm; 0‒15cm) under three legume species (alfalfa, cicer milkvetch and sainfoin) three times (spring, summer and fall of 2019) across three landscape positions. Legume species did not affect the measured parameters. Over time, tillage affected DOC, TDN, and inorganic N. Averaged across three pasture legumes and three landscape positions, tillage increased DOC 29% by summer. Fall-applied tillage led to 59% and 33% higher TDN in the succeeding summer and fall. Inorganic N increased by 14% and 40% across landscape positions and sampling after tillage. Averaged across landscape positions, MBC decreased by 31% from spring to summer and increased by 51% from summer to fall. However, MBN increased by 53% and decreased by 5% within the same period. The seasonal fluctuations in MBC/MBN reflected variations in moisture, temperature, and substrate quality. Total SOC, LFOC, and LFON increased on the upper slopes and fall sampling time. Although single intensive tillage did not affect total SOC, several tillage operations could accelerate SOM loss and reduced total C storage over time.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
leaf against strongyle and coccidia infections in sheep
No full textGastro intestinal parasites are developing resistance to various commercial anthelminthics. Hence, the need to explore the efficacies of herbal plants against gastro-intestinal parasites. The study was therefore conducted to determine the efficacy of aqueous extract of Vernonia amygdalina leaf against strongyles and coccidia spp. in sheep.A total of 60 sheep were used for the study. The animals were randomly assigned to one of the four groups. Those in group A, B, C and D were given albendazole (ABZ), 10% aqueous V. amygdalina extract (BL10), 20% aqueous V. amygdalina extract (BL20) and 10ml distilled water (Dw) respectively. All four treatments were given orally, depending on the body weight of the animals, with the exception of the distilled water which was constant (10ml) for each animal. Fecal samples were collected from each sheep and examined using McMaster technique. The data were analyzed using R version 4.2. The study brought to light that the prevalence of strongyles in sheep was 70% in the study area at pre-treatment. BL10 had efficacies of 52.58% and 65.08% against strongyles and coccidia spp. respectively. BL20 produced similar anthelmintic effect against strongyles as albendazole. Strongyle spp. showed resistance against albendazole in the study area.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
prevalence and priority strategies in maize (Zea mays L)
No full textCopyright ©2015 Author(s) retain the copyright of this articl
Analysis of meningitis outbreak data, Jaman North District, Brong Ahafo Region, Ghana
No full textBackground: Descriptive analysis of meningitis outbreak in Jaman North districts of Brong Ahafo Region.Design: Descriptive secondary data analysisData Source: records of meningitis cases were extracted from case-based forms and line list.Main outcome measure: The source and pattern of outbreakResults: A total of 367 suspected cases with 44 confirmed were recorded from Jaman North during the period of January to March 2016. The mean age of those affected was 58 ± 13years. The case fatality rate was 0.82% and the proportion of males to females was 1:1.3 (160/207). The age group most affected was 15-29 years (54.7%) and the least was 45-49 years (3.0%). Streptococcus pneumoniae formed 77.3% of confirmed cases whilst Neisseria meningitides was 20.5%. Cases with Neisseria meningitides came from a border town in La Côte d’Ivoire.Conclusion: A protracted propagated meningitis outbreak occurred; and the predominant bacteria strain among confirmed cases was Streptococcus pneumoniae. Cases were mainly females and the most vulnerable group were people aged 15-29 years.Keywords: Streptococcus pneumoniae, Neisseria meningitides, meningitis outbreak, Jaman North District, GhanaFunding: This work was funded by the authors. Author BKD was sponsored under CDC (Frontline FETP)-CDC CoAg 6NU2GGH001876
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