The classification performance of Bayesian Networks Classifiers: a case study of detecting Denial of Service (DoS) attacks in cloud computing environments

In this research we propose a Bayesian networks approach as a promissory classification technique for detecting malicious traffic due to Denial of Service (DoS) attacks. Bayesian networks have been applied in numerous fields fraught with uncertainty and they have been proved to be successful. They have excelled tremendously in classification tasks i.e. text analysis, medical diagnoses and environmental modeling and management. The detection of DoS attacks has received tremendous attention in the field of network security. DoS attacks have proved to be detrimental and are the bane of cloud computing environments. Large business enterprises have been/or are still unwilling to outsource their businesses to the cloud due to the intrusive tendencies that the cloud platforms are prone too. To make use of Bayesian networks it is imperative to understand the ―ecosystem‖ of factors that are external to modeling the Bayesian algorithm itself. Understanding these factors have proven to result in comparable improvement in classification performance beyond the augmentation of the existing algorithms. Literature provides discussions pertaining to the factors that impact the classification capability, however it was noticed that the effects of the factors are not universal, they tend to be unique for each domain problem. This study investigates the effects of modeling parameters on the classification performance of Bayesian network classifiers in detecting DoS attacks in cloud platforms. We analyzed how structural complexity, training sample size, the choice of discretization method and lastly the score function both individually and collectively impact the performance of classifying between normal and DoS attacks on the cloud. To study the aforementioned factors, we conducted a series of experiments in detecting live DoS attacks launched against a deployed cloud and thereafter examined the classification performance in terms of accuracy of different classes of Bayesian networks. NSL-KDD dataset was used as our training set. We used ownCloud software to deploy our cloud platform. To launch DoS attacks, we used hping3 hacker friendly utility. A live packet capture was used as our test set. WEKA version 3.7.12 was used for our experiments. Our results show that the progression in model complexity improves the classification performance. This is attributed to the increase in the number of attribute correlations. Also the size of the training sample size proved to improve classification ability. Our findings noted that the choice of discretization algorithm does matter in the quest for optimal classification performance. Furthermore, our results indicate that the choice of scoring function does not affect the classification performance of Bayesian networks. Conclusions drawn from this research are prescriptive particularly for a novice machine learning researcher with valuable recommendations that ensure optimal classification performance of Bayesian networks classifiers

TUBER NECROSIS-CAUSING VIRUSES OF POTATO: GENETIC DIVERSITY AND HOST-PATHOGEN INTERACTIONS

Potato (Solanum tuberosum L.) is an economically important staple crop. Tuber necrosis-causing viruses of potato such as Potato virus Y (PVY) and Tobacco rattle virus (TRV) threaten potato production due to qualitative and quantitative tuber losses they can cause, that have economic costs. There is need to elucidate virus-host interactions and evolutionary dynamics of the potato viruses to help develop novel diagnosis and disease management strategies. Plant defense RNA-silencing mechanisms deployed against viruses produce virus small interfering RNAs (vsiRNAs) to degrade homologous viral transcripts. Based on sequence complementarity, the vsiRNAs can potentially degrade host RNA transcripts. This study, therefore, exploited bioinformatics and genomics tools to elucidate the transcriptome level interactions between the potato transcriptome and PVY-derived vsiRNAs of three PVY strains: PVYN, PVYNTN and PVYO. The most abundant targeted, non-coding RNA transcripts, for the strain specific PVY-derived vsiRNAs were found to be small nucleolar and ribosomal RNAs. Functional annotation and qRT-PCR validation suggested that the vsiRNAs target potato genes are involved in plant hormone signaling, plant-pathogen interactions, plant defense and stress response processes. Additionally, RNA viruses are prone to rapid evolution that could result in the emergence of more virulent and resistance-breaking strains. As such, genetic diversity studies are crucial to assess the virus population structure and evolutionary dynamics. In this study, the genetic diversity of TRV isolates from potato growing regions in the USA was elucidated. The genome of TRV is segmented into two, RNA1 and RNA2. Phylogenetic analysis of RNA2 genes, coat protein and nematode transmission (2b) nucleotide sequences revealed tendency for geographical adaptation of TRV while recombination analysis on RNA1 suggested isolates from Idaho, North Dakota, Colorado and Michigan as recombinants between American and European isolates. The replicase genes were found to be largely conserved and exhibited positive diversification in non-potato TRV isolate suggesting involvement in host adaptation. The 1b gene in RNA1 was observed to be less constrained compared to other RNA1 genes, this relates to its function as suppressor of RNA-silencing and could enable it to keep up with the evolutionary war in virus-host interactions. New insights into potato-virus interaction and virus evolution were revealed

Social, Cultural, and Environmental Challenges Faced by Children on Antiretroviral Therapy in Zimbabwe: a Mixed Method Study

Objectives:Despite the advent of antiretroviral therapy (ART), many children, particularly in the rural communities of Zimbabwe, remain vulnerable. The purpose of this study was to determine the factors and challenges facing children on antiretroviral therapy (ART) in Brunapeg area of Mangwe District, Zimbabwe.Methods:A mixed-method approach involving interviewer-guided focus group discussions and piloted semi-structured questionnaires was utilized to collect data from different key population groups. The data obtained were analyzed through content coding procedures based on a set of predetermined themes of interest.Results:A number of challenges emerged as barriers to the success of antiretroviral therapy for children. Primary care givers were less informed about HIV and AIDS issues for people having direct impact on the success of antiretroviral therapy in children whilst some were found to be taking the antiretroviral drugs meant for the children. It also emerged that some primary care givers were either too young or too old to care for the children while others had failed to disclose to the children why they frequently visited the Opportunistic Infections (OI) clinic. Most primary care givers were not the biological parents of the affected children. Other challenges included inadequate access to health services, inadequate food and nutrition and lack of access to clean water, good hygiene and sanitation. The lack of community support and stigma and discrimination affected their school attendance and hospital visits. All these factors contributed to non-adherence to antiretroviral drugs.Conclusions and Public Health Implications:Children on ART in rural communities in Zimbabwe remain severely compromised and have unique problems that need multi-intervention strategies both at policy and programmatic levels. Effective mitigating measures must be fully established and implemented in rural communities of developing countries in the fight for universal elimination of HIV/AIDS

Social, Cultural, and Environmental Challenges Faced by Children on Antiretroviral Therapy in Zimbabwe: a Mixed Method Study

Objectives Despite the advent of antiretroviral therapy (ART), many children, particularly in the rural communities of Zimbabwe, remain vulnerable. The purpose of this study was to determine the factors and challenges facing children on antiretroviral therapy (ART) in Brunapeg area of Mangwe District, Zimbabwe. Methods A mixed-method approach involving interviewer-guided focus group discussions and piloted semi-structured questionnaires was utilized to collect data from different key population groups. The data obtained were analyzed through content coding procedures based on a set of predetermined themes of interest. Results A number of challenges emerged as barriers to the success of antiretroviral therapy for children. Primary care givers were less informed about HIV and AIDS issues for people having direct impact on the success of antiretroviral therapy in children whilst some were found to be taking the antiretroviral drugs meant for the children. It also emerged that some primary care givers were either too young or too old to care for the children while others had failed to disclose to the children why they frequently visited the Opportunistic Infections (OI) clinic. Most primary care givers were not the biological parents of the affected children. Other challenges included inadequate access to health services, inadequate food and nutrition and lack of access to clean water, good hygiene and sanitation. The lack of community support and stigma and discrimination affected their school attendance and hospital visits. All these factors contributed to non-adherence to antiretroviral drugs. Conclusions and Public Health Implications: Children on ART in rural communities in Zimbabwe remain severely compromised and have unique problems that need multi-intervention strategies both at policy and programmatic levels. Effective mitigating measures must be fully established and implemented in rural communities of developing countries in the fight for universal elimination of HIV/AIDS. Key Words: Antiretroviral therapy • Challenges • Children • HIV/AIDS • Mangwe District • Zimbabw

The effects of potato virus Y-derived virus small interfering RNAs of three biologically distinct strains on potato (Solanum tuberosum) transcriptome

Potato virus Y (PVY) is one of the most economically important pathogen of potato that is present as biologically distinct strains. The virus-derived small interfering RNAs (vsiRNAs) from potato cv. Russet Burbank individually infected with PVY-N, PVY-NTN and PVY-O strains were recently characterized. Plant defense RNA-silencing mechanisms deployed against viruses produce vsiRNAs to degrade homologous viral transcripts. Based on sequence complementarity, the vsiRNAs can potentially degrade host RNA transcripts raising the prospect of vsiRNAs as pathogenicity determinants in virus-host interactions. This study investigated the global effects of PVY vsiRNAs on the host potato transcriptome.The strain-specific vsiRNAs of PVY, expressed in high copy number, were analyzed in silico for their proclivity to target potato coding and non-coding RNAs using psRobot and psRNATarget algorithms. Functional annotation of target coding transcripts was carried out to predict physiological effects of the vsiRNAs on the potato cv. Russet Burbank. The downregulation of selected target coding transcripts was further validated using qRT-PCR.The vsiRNAs derived from biologically distinct strains of PVY displayed diversity in terms of absolute number, copy number and hotspots for siRNAs on their respective genomes. The vsiRNAs populations were derived with a high frequency from 6\ua0K1, P1 and Hc-Pro for PVY-N, P1, Hc-Pro and P3 for PVY-NTN, and P1, 3' UTR and NIa for PVY-O genomic regions. The number of vsiRNAs that displayed interaction with potato coding transcripts and number of putative coding target transcripts were comparable between PVY-N and PVY-O, and were relatively higher for PVY-NTN. The most abundant target non-coding RNA transcripts for the strain specific PVY-derived vsiRNAs were found to be MIR821, 28S rRNA,18S rRNA, snoR71, tRNA-Met and U5. Functional annotation and qRT-PCR validation suggested that the vsiRNAs target genes involved in plant hormone signaling, genetic information processing, plant-pathogen interactions, plant defense and stress response processes in potato.The findings suggested that the PVY-derived vsiRNAs could act as a pathogenicity determinant and as a counter-defense strategy to host RNA silencing in PVY-potato interactions. The broad range of host genes targeted by PVY vsiRNAs in infected potato suggests a diverse role for vsiRNAs that includes suppression of host stress responses and developmental processes. The interactome scenario is the first report on the interaction between one of the most important Potyvirus genome-derived siRNAs and the potato transcripts

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Not AvailableBackground Potato virus Y (PVY) is one of the most economically important pathogen of potato that is present as biologically distinct strains. The virus-derived small interfering RNAs (vsiRNAs) from potato cv. Russet Burbank individually infected with PVY-N, PVY-NTN and PVY-O strains were recently characterized. Plant defense RNA-silencing mechanisms deployed against viruses produce vsiRNAs to degrade homologous viral transcripts. Based on sequence complementarity, the vsiRNAs can potentially degrade host RNA transcripts raising the prospect of vsiRNAs as pathogenicity determinants in virus-host interactions. This study investigated the global effects of PVY vsiRNAs on the host potato transcriptome. Methods The strain-specific vsiRNAs of PVY, expressed in high copy number, were analyzed in silico for their proclivity to target potato coding and non-coding RNAs using psRobot and psRNATarget algorithms. Functional annotation of target coding transcripts was carried out to predict physiological effects of the vsiRNAs on the potato cv. Russet Burbank. The downregulation of selected target coding transcripts was further validated using qRT-PCR. Results The vsiRNAs derived from biologically distinct strains of PVY displayed diversity in terms of absolute number, copy number and hotspots for siRNAs on their respective genomes. The vsiRNAs populations were derived with a high frequency from 6 K1, P1 and Hc-Pro for PVY-N, P1, Hc-Pro and P3 for PVY-NTN, and P1, 3′ UTR and NIa for PVY-O genomic regions. The number of vsiRNAs that displayed interaction with potato coding transcripts and number of putative coding target transcripts were comparable between PVY-N and PVY-O, and were relatively higher for PVY-NTN. The most abundant target non-coding RNA transcripts for the strain specific PVY-derived vsiRNAs were found to be MIR821, 28S rRNA,18S rRNA, snoR71, tRNA-Met and U5. Functional annotation and qRT-PCR validation suggested that the vsiRNAs target genes involved in plant hormone signaling, genetic information processing, plant-pathogen interactions, plant defense and stress response processes in potato. Conclusions The findings suggested that the PVY-derived vsiRNAs could act as a pathogenicity determinant and as a counter-defense strategy to host RNA silencing in PVY-potato interactions. The broad range of host genes targeted by PVY vsiRNAs in infected potato suggests a diverse role for vsiRNAs that includes suppression of host stress responses and developmental processes. The interactome scenario is the first report on the interaction between one of the most important Potyvirus genome-derived siRNAs and the potato transcripts.Not Availabl