title: Effectiveness of entropy-based features in high-and low-intensity DDoS attacks detection

authors: Koay, Abigail

subjects: computer science

abstract: DDoS attack detection using entropy-based features in network traffic has become a popular approach among researchers in the last five years. The use of traffic distribution features constructed using entropy measures has been proposed as a better approach to detect Distributed Denial of Service (DDoS) attacks compared to conventional volumetric methods, but it still lacks in the generality of detecting various intensity DDoS attacks accurately. In this paper, we focus on identifying effective entropy-based features to detect both high- and low-intensity DDoS attacks by exploring the effectiveness of entropy-based features in distinguishing the attack from normal traffic patterns. We hypothesise that using different entropy measures, window sizes, and entropy-based features may affect the accuracy of detecting DDoS attacks. This means that certain entropy measures, window sizes, and entropy-based features may reveal attack traffic amongst normal traffic better than the others. Our experimental results show that using Shannon, Tsallis and Zhou entropy measures can achieve a clearer distinction between DDoS attack traffic and normal traffic than Rényi entropy. In addition, the window size setting used in entropy construction has minimal influence in differentiating between DDoS attack traffic and normal traffic. The result of the effectiveness ranking shows that the commonly used features are less effective than other features extracted from traffic headers.

text: Effectiveness of entropy-based features in high-and low-intensity DDoS attacks detection DDoS attack detection using entropy-based features in network traffic has become a popular approach among researchers in the last five years. The use of traffic distribution features constructed using entropy measures has been proposed as a better approach to detect Distributed Denial of Service (DDoS) attacks compared to conventional volumetric methods, but it still lacks in the generality of detecting various intensity DDoS attacks accurately. In this paper, we focus on identifying effective entropy-based features to detect both high- and low-intensity DDoS attacks by exploring the effectiveness of entropy-based features in distinguishing the attack from normal traffic patterns. We hypothesise that using different entropy measures, window sizes, and entropy-based features may affect the accuracy of detecting DDoS attacks. This means that certain entropy measures, window sizes, and entropy-based features may reveal attack traffic amongst normal traffic better than the others. Our experimental results show that using Shannon, Tsallis and Zhou entropy measures can achieve a clearer distinction between DDoS attack traffic and normal traffic than Rényi entropy. In addition, the window size setting used in entropy construction has minimal influence in differentiating between DDoS attack traffic and normal traffic. The result of the effectiveness ranking shows that the commonly used features are less effective than other features extracted from traffic headers.

year: 2019

title: Prospects of climate resilient infrastructure in the low-income informal settlements of Dhaka - A community approach

authors: Rahman, Sowmen

abstract: This thesis focuses on the prospects of climate resilient infrastructure in the low-income settlements of Dhaka city. Numerous research findings show that low-income communities of Dhaka are living in the hazard prone areas with poor housing, sanitation and drainage facilities. These communities are at high risk of predicted climate change impacts and may be unable to avoid the direct and indirect impacts of climatic disasters. Most of the houses are below the ground level of Dhaka city and remain inundated after heavy rainfall or flood. In this context, this research undertook a community approach to explore the required measures for building climate resilience in the infrastructures of low-income settlements. Special attention was given on the impacts of heavy rainfall and storms and how they affect the infrastructure system.

This study selected Beguntila slum and New Purba Kurmitola Camp as a sample after carefully evaluating the selection criteria for this research.  To derive information from the field, this study applied qualitative data collection techniques. Reconnaissance surveys were conducted on both slums to get a primary idea about the vulnerabilities of these slums. In this study, separate male and female focus group discussions were conducted in both slums. Ten key community experts were also selected for the key informant interviews. Drawing on qualitative data collected through focus group discussions and key informant interviews, this study examines the infrastructural vulnerabilities of these slums due to climate change impacts. It then identifies the root causes for these vulnerabilities. Finally, it outlines the required measures for establishing climate resilient infrastructure in these settlements. 

The findings demonstrate that the key reason for these vulnerabilities on infrastructure due to heavy rainfall is inefficiency of current drainage system in the slum areas. This situation becomes even worse in absence of a functioning sewerage system. The tin-shed houses were found to be very weak and unable to withstand strong winds during storms. It was also found that electric poles could collapse on tin-shed houses and roads causing injuries to slum dwellers. The analysis finds that poverty is the most impeding factor for the advancement of the slum infrastructure. To conclude, the study urges the need for collective effort by government and NGOs to address the issues and take a range of structural and non-structural measures to build climate resilience in the low-income settlements of Dhaka city.

text: Prospects of climate resilient infrastructure in the low-income informal settlements of Dhaka - A community approach This thesis focuses on the prospects of climate resilient infrastructure in the low-income settlements of Dhaka city. Numerous research findings show that low-income communities of Dhaka are living in the hazard prone areas with poor housing, sanitation and drainage facilities. These communities are at high risk of predicted climate change impacts and may be unable to avoid the direct and indirect impacts of climatic disasters. Most of the houses are below the ground level of Dhaka city and remain inundated after heavy rainfall or flood. In this context, this research undertook a community approach to explore the required measures for building climate resilience in the infrastructures of low-income settlements. Special attention was given on the impacts of heavy rainfall and storms and how they affect the infrastructure system.

This study selected Beguntila slum and New Purba Kurmitola Camp as a sample after carefully evaluating the selection criteria for this research.  To derive information from the field, this study applied qualitative data collection techniques. Reconnaissance surveys were conducted on both slums to get a primary idea about the vulnerabilities of these slums. In this study, separate male and female focus group discussions were conducted in both slums. Ten key community experts were also selected for the key informant interviews. Drawing on qualitative data collected through focus group discussions and key informant interviews, this study examines the infrastructural vulnerabilities of these slums due to climate change impacts. It then identifies the root causes for these vulnerabilities. Finally, it outlines the required measures for establishing climate resilient infrastructure in these settlements. 

The findings demonstrate that the key reason for these vulnerabilities on infrastructure due to heavy rainfall is inefficiency of current drainage system in the slum areas. This situation becomes even worse in absence of a functioning sewerage system. The tin-shed houses were found to be very weak and unable to withstand strong winds during storms. It was also found that electric poles could collapse on tin-shed houses and roads causing injuries to slum dwellers. The analysis finds that poverty is the most impeding factor for the advancement of the slum infrastructure. To conclude, the study urges the need for collective effort by government and NGOs to address the issues and take a range of structural and non-structural measures to build climate resilience in the low-income settlements of Dhaka city.

year: 2018

title: Possibilities of transformation: discourses of difference in organisational communication

authors: Jones, Deborah Helen

abstract: In this thesis I set out to create an interdisciplinary location from which to address the relationship between gender and communication in an organisational context. I draw on feminist and post-structuralist theory to ask the question: How is ‘difference’ constructed in organisational communication? I use the term ‘difference’ here to indicate that I am interested in how ‘gender’ works in relationship with other kinds of difference, especially in relation to ethnic difference.

My thesis is intended as a contribution to feminist communication theory, and specifically, to the emerging field of feminist organisational communication. Because of the approach I take to ‘communication’, this project addresses broad issues of identity, agency and discourse in organisations. In this sense, I also see the thesis as a contribution to organisational studies, and particularly to the study of organisational discourse, which opens up new relationships between ‘organisation’ and ‘communication’. Interdisciplinarity itself is a key issue in my thesis, as I set out to create connections between disciplinary fields in the service of contesting them, rather than seeking to create new boundaries. A second key focus is the development of theoretical sophistication in the field of gender and communication. I draw on feminist/post-structuralist theory, especially feminist readings of Michel Foucault’s work to generate this development. My third key focus is the issue of agency, which I see as central to theorising organisational transformation, and also as central to re-thinking communication theory.

My writing strategies demonstrate my commitments to reflexivity in developing feminist/post-structuralist research epistemologies, and I experiment with ways of paying attention to issues of authority throughout the thesis. This thesis is divided into two main parts. In Chapters 2 to 6, I set up a theoretical framework for feminist/post-structuralist accounts of gender and ethnicity, and weave this theory through the literatures of ‘gender and communication’, ‘cross-cultural communication’, and ‘organisational communication’. I set out to produce an ‘autocritique’, an opportunity to draw on developments in post-structuralist theory to think differently about feminist ‘organisational communication’, putting it within a broader framework of ‘difference’.

In the second part of the thesis, Chapters 7 to 12, I put issues generated by this theoretical framework in a specific organisational context, asking: How are gender and ethnic differences constructed in the discourses of Equal Employment Opportunities (EEO) and Biculturalism in New Zealand government organisations? Chapters 7 and 8 introduce my field studies methodology and research subjects, and provide background narratives which frame the historical and cultural context in which they were carried out. In Chapters 9 to 12 I carry out a discourse analysis of interviews with EEO and Biculturalism practitioners, and also analyse published and unpublished documents associated with ‘difference’ in employment policies. These accounts of field studies are intended as a series of experiments with theorising ‘organisational communication’ in different ways. I complete the thesis with a ‘Review’ (Chapter 13) in which I reflect on key theoretical threads, and on further questions that emerged during the project.

text: Possibilities of transformation: discourses of difference in organisational communication In this thesis I set out to create an interdisciplinary location from which to address the relationship between gender and communication in an organisational context. I draw on feminist and post-structuralist theory to ask the question: How is ‘difference’ constructed in organisational communication? I use the term ‘difference’ here to indicate that I am interested in how ‘gender’ works in relationship with other kinds of difference, especially in relation to ethnic difference.

My thesis is intended as a contribution to feminist communication theory, and specifically, to the emerging field of feminist organisational communication. Because of the approach I take to ‘communication’, this project addresses broad issues of identity, agency and discourse in organisations. In this sense, I also see the thesis as a contribution to organisational studies, and particularly to the study of organisational discourse, which opens up new relationships between ‘organisation’ and ‘communication’. Interdisciplinarity itself is a key issue in my thesis, as I set out to create connections between disciplinary fields in the service of contesting them, rather than seeking to create new boundaries. A second key focus is the development of theoretical sophistication in the field of gender and communication. I draw on feminist/post-structuralist theory, especially feminist readings of Michel Foucault’s work to generate this development. My third key focus is the issue of agency, which I see as central to theorising organisational transformation, and also as central to re-thinking communication theory.

My writing strategies demonstrate my commitments to reflexivity in developing feminist/post-structuralist research epistemologies, and I experiment with ways of paying attention to issues of authority throughout the thesis. This thesis is divided into two main parts. In Chapters 2 to 6, I set up a theoretical framework for feminist/post-structuralist accounts of gender and ethnicity, and weave this theory through the literatures of ‘gender and communication’, ‘cross-cultural communication’, and ‘organisational communication’. I set out to produce an ‘autocritique’, an opportunity to draw on developments in post-structuralist theory to think differently about feminist ‘organisational communication’, putting it within a broader framework of ‘difference’.

In the second part of the thesis, Chapters 7 to 12, I put issues generated by this theoretical framework in a specific organisational context, asking: How are gender and ethnic differences constructed in the discourses of Equal Employment Opportunities (EEO) and Biculturalism in New Zealand government organisations? Chapters 7 and 8 introduce my field studies methodology and research subjects, and provide background narratives which frame the historical and cultural context in which they were carried out. In Chapters 9 to 12 I carry out a discourse analysis of interviews with EEO and Biculturalism practitioners, and also analyse published and unpublished documents associated with ‘difference’ in employment policies. These accounts of field studies are intended as a series of experiments with theorising ‘organisational communication’ in different ways. I complete the thesis with a ‘Review’ (Chapter 13) in which I reflect on key theoretical threads, and on further questions that emerged during the project.

year: 1998