title: Malware Propagation and Prevention Model for Time-Varying Community Networks within Software Defined Networks

authors: Liu, Lan

subjects: Science & Technology

abstract: As the adoption of Software Defined Networks (SDNs) grows, the security of SDN still has several unaddressed limitations. A key network security research area is in the study of malware propagation across the SDN-enabled networks. To analyze the spreading processes of network malware (e.g., viruses) in SDN, we propose a dynamic model with a time-varying community network, inspired by research models on the spread of epidemics in complex networks across communities. We assume subnets of the network as communities and links that are dense in subnets but sparse between subnets. Using numerical simulation and theoretical analysis, we find that the efficiency of network malware propagation in this model depends on the mobility rate q of the nodes between subnets. We also find that there exists a mobility rate threshold 𝑞𝑐. The network malware will spread in the SDN when the mobility rate 𝑞 > 𝑞𝑐. The malware will survive when 𝑞 > 𝑞𝑐 and perish when 𝑞 < 𝑞𝑐. The results showed that our model is effective, and the results may help to decide the SDN control strategy to defend against network malware and provide a theoretical basis to reduce and prevent network security incidents.

text: Malware Propagation and Prevention Model for Time-Varying Community Networks within Software Defined Networks As the adoption of Software Defined Networks (SDNs) grows, the security of SDN still has several unaddressed limitations. A key network security research area is in the study of malware propagation across the SDN-enabled networks. To analyze the spreading processes of network malware (e.g., viruses) in SDN, we propose a dynamic model with a time-varying community network, inspired by research models on the spread of epidemics in complex networks across communities. We assume subnets of the network as communities and links that are dense in subnets but sparse between subnets. Using numerical simulation and theoretical analysis, we find that the efficiency of network malware propagation in this model depends on the mobility rate q of the nodes between subnets. We also find that there exists a mobility rate threshold 𝑞𝑐. The network malware will spread in the SDN when the mobility rate 𝑞 > 𝑞𝑐. The malware will survive when 𝑞 > 𝑞𝑐 and perish when 𝑞 < 𝑞𝑐. The results showed that our model is effective, and the results may help to decide the SDN control strategy to defend against network malware and provide a theoretical basis to reduce and prevent network security incidents.

year: 2017

title: Microbial diversity in relation to human activity in historic areas of Ross Dependency, Antarctica

authors: Minasaki, Ryuji

abstract: The goal of this study was to undertake a relatively broad microbiological investigation at historic areas of Cape Evans and Ross Island. The two phylogenetically diverse targets were Bacillus anthracis, the causative agent for anthrax disease, and filamentous micro-fungi associated food products. The human activities were presumed to have played a significant contribution to the introduction of non-indigenous Bacillus anthracis and many filamentous micro-fungi at the historic areas on Ross Island. 

Bacillus anthracis was suspected to be present at Cape Evans based on a circumstantial clinical analysis of the death of the member in Captain Robert F Scott's Terra Nova Expedition in 1912. Detection methods based on polymerase chain reaction (PCR) targeting B. anthracis specific genes on chromosome and two plasmids were employed. DNA extraction was performed by a bead-beating technique from 74 environmental samples. PCR efficiency was compromised probably due to inhibitors in DNA extracts, but improved with higher concentrations of Taq polymerase. Initially a total of 74 environmental samples were screened with one set of primers before positively tested 19 samples were rigorously investigated with seven sets of primers. Nested PCR also increased the target specificity and detection levels. Sequence analyses of the several positive samples from PCR reactions were characteristic to B. anthracis. 

A diverse range of filamentous micro-fungi were isolated on three different media at two different temperatures, 15 °C and 25 °C, and identified by classical morphological taxonomy from the foodstuffs and internal environmental samples of Captain Robert F Scott's historic hut at Hut Point built in 1901. In total, there were 22 taxa and 14 genera recorded including many cosmopolitan species isolated from the samples, in particular Penicillium species. An extensive literature review of the :filamentous micro-fungi found in Antarctica identified that 7 taxa isolated in the study were not reported previously. Many isolates were obtained at 15 °C while some isolates grew in the presence of antibiotics.

text: Microbial diversity in relation to human activity in historic areas of Ross Dependency, Antarctica The goal of this study was to undertake a relatively broad microbiological investigation at historic areas of Cape Evans and Ross Island. The two phylogenetically diverse targets were Bacillus anthracis, the causative agent for anthrax disease, and filamentous micro-fungi associated food products. The human activities were presumed to have played a significant contribution to the introduction of non-indigenous Bacillus anthracis and many filamentous micro-fungi at the historic areas on Ross Island. 

Bacillus anthracis was suspected to be present at Cape Evans based on a circumstantial clinical analysis of the death of the member in Captain Robert F Scott's Terra Nova Expedition in 1912. Detection methods based on polymerase chain reaction (PCR) targeting B. anthracis specific genes on chromosome and two plasmids were employed. DNA extraction was performed by a bead-beating technique from 74 environmental samples. PCR efficiency was compromised probably due to inhibitors in DNA extracts, but improved with higher concentrations of Taq polymerase. Initially a total of 74 environmental samples were screened with one set of primers before positively tested 19 samples were rigorously investigated with seven sets of primers. Nested PCR also increased the target specificity and detection levels. Sequence analyses of the several positive samples from PCR reactions were characteristic to B. anthracis. 

A diverse range of filamentous micro-fungi were isolated on three different media at two different temperatures, 15 °C and 25 °C, and identified by classical morphological taxonomy from the foodstuffs and internal environmental samples of Captain Robert F Scott's historic hut at Hut Point built in 1901. In total, there were 22 taxa and 14 genera recorded including many cosmopolitan species isolated from the samples, in particular Penicillium species. An extensive literature review of the :filamentous micro-fungi found in Antarctica identified that 7 taxa isolated in the study were not reported previously. Many isolates were obtained at 15 °C while some isolates grew in the presence of antibiotics.

year: 2003

title: Do two rights fix a wrong? A study of employee and organizational responses to abusive supervision in New Zealand

authors: de Fluiter, Alida Jane

subjects: Abusive supervision

abstract: Organizational justice theories suggest that employees who are abused by their supervisor are likely to respond with lower job and personal outcomes. However, an under-explored area has been the influence of support perceptions. The present study suggests that perceived supervisor support (PSS) and perceived organizational support (POS) may moderate the influence of abusive supervision, and this was tested with three-way interactions. Data was collected from two samples: (1) 100 blue-collar workers in construction and (2) 218 random Maori employees from a variety of industries and professions. Structural equation modeling confirmed the unique constructs of the study measures towards abusive supervision and PSS and POS. Direct effects showed abusive supervision was significant and negative in both samples towards life satisfaction, job satisfaction, and organizational-based self-esteem (OBSE), and significant and positive in both samples towards turnover intentions, anxiety, depression, and insomnia. The results indicated that abusive supervision accounted for large amounts of variance towards all outcomes, with the exception of life satisfaction in study two (7%), and insomnia (8% in study one, and 4% in study two), ranging from 13%-32% variance. Significant three-way interactions were found for all outcomes except turnover intentions and insomnia. The three-way interaction towards life satisfaction in study one indicated that under abusive supervision, respondents with high PSS and high POS experienced the greatest levels of life satisfaction. Similar relationships were found toward depression (study one and two) and anxiety (study one), showing that respondents who experienced high abusive supervision, high PSS, and high POS had the lowest levels of negative mental health outcomes amongst all abused respondents. This suggested a potentially cumulative effect of multiple sources of support. Furthermore, towards job satisfaction in study two, findings show respondents with high abusive supervision and high POS reported the highest job satisfaction, irrespective of levels of PSS. A similar relationship was found toward OBSE in study two, suggesting that of the support variables examined, POS may have greater effect on outcomes, thereby supporting research of Dawley, Andrews and Bucklew (2008) who found POS to be the best predictor of organizational outcomes. Overall, this paper supports the notion that perceptions of support may moderate the influence of abusive supervision perceptions on employee’s work and personal outcomes. The findings show that while abusive supervision can play a dominant role on outcomes, this can be somewhat nullified by greater support from the organization. This has strong implications for firms dealing with problem supervisors, signaling the importance of establishing POS, and emphasizing that creating a supportive organization may be the first step to enabling employees to develop positive work and individual outcomes.

text: Do two rights fix a wrong? A study of employee and organizational responses to abusive supervision in New Zealand Organizational justice theories suggest that employees who are abused by their supervisor are likely to respond with lower job and personal outcomes. However, an under-explored area has been the influence of support perceptions. The present study suggests that perceived supervisor support (PSS) and perceived organizational support (POS) may moderate the influence of abusive supervision, and this was tested with three-way interactions. Data was collected from two samples: (1) 100 blue-collar workers in construction and (2) 218 random Maori employees from a variety of industries and professions. Structural equation modeling confirmed the unique constructs of the study measures towards abusive supervision and PSS and POS. Direct effects showed abusive supervision was significant and negative in both samples towards life satisfaction, job satisfaction, and organizational-based self-esteem (OBSE), and significant and positive in both samples towards turnover intentions, anxiety, depression, and insomnia. The results indicated that abusive supervision accounted for large amounts of variance towards all outcomes, with the exception of life satisfaction in study two (7%), and insomnia (8% in study one, and 4% in study two), ranging from 13%-32% variance. Significant three-way interactions were found for all outcomes except turnover intentions and insomnia. The three-way interaction towards life satisfaction in study one indicated that under abusive supervision, respondents with high PSS and high POS experienced the greatest levels of life satisfaction. Similar relationships were found toward depression (study one and two) and anxiety (study one), showing that respondents who experienced high abusive supervision, high PSS, and high POS had the lowest levels of negative mental health outcomes amongst all abused respondents. This suggested a potentially cumulative effect of multiple sources of support. Furthermore, towards job satisfaction in study two, findings show respondents with high abusive supervision and high POS reported the highest job satisfaction, irrespective of levels of PSS. A similar relationship was found toward OBSE in study two, suggesting that of the support variables examined, POS may have greater effect on outcomes, thereby supporting research of Dawley, Andrews and Bucklew (2008) who found POS to be the best predictor of organizational outcomes. Overall, this paper supports the notion that perceptions of support may moderate the influence of abusive supervision perceptions on employee’s work and personal outcomes. The findings show that while abusive supervision can play a dominant role on outcomes, this can be somewhat nullified by greater support from the organization. This has strong implications for firms dealing with problem supervisors, signaling the importance of establishing POS, and emphasizing that creating a supportive organization may be the first step to enabling employees to develop positive work and individual outcomes.

year: 2011