13,991 research outputs found
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A tale of two anomies: some observations on the contribution of (sociological) criminological theory to explaining hate crime motivation
This paper argues that hate crime is simply an inherent and normal component of contemporary society. Regardless of a concerted intervention – legislative, situational and social crime prevention – against this significant social problem in the USA and Europe in recent years, there remains a ubiquitous, albeit often latent, continued existence of hate motivation throughout society which remains at a considerable and increasing risk of actualisation as individuals come into contact with other likeminded individuals. This is particularly an issue in the information age which has greatly enhanced the spatial proximity of these hate-minded people to each other. It is shown that an established body of sociologically informed criminological theory – in particular that founded on the European and US anomie traditions – can be adapted to explain and understand the existence and persistence of hate motivation at all levels of the social world. This provides the basis for an extensive educative - and thus preventive - programme to tackle pervasive cultures of hate
Wide spectrum attribution: Using deception for attribution intelligence in cyber attacks
Modern cyber attacks have evolved considerably. The skill level required to conduct
a cyber attack is low. Computing power is cheap, targets are diverse and plentiful.
Point-and-click crimeware kits are widely circulated in the underground economy, while
source code for sophisticated malware such as Stuxnet is available for all to download
and repurpose. Despite decades of research into defensive techniques, such as firewalls,
intrusion detection systems, anti-virus, code auditing, etc, the quantity of successful
cyber attacks continues to increase, as does the number of vulnerabilities identified.
Measures to identify perpetrators, known as attribution, have existed for as long as there
have been cyber attacks. The most actively researched technical attribution techniques
involve the marking and logging of network packets. These techniques are performed
by network devices along the packet journey, which most often requires modification of
existing router hardware and/or software, or the inclusion of additional devices. These
modifications require wide-scale infrastructure changes that are not only complex and
costly, but invoke legal, ethical and governance issues. The usefulness of these techniques
is also often questioned, as attack actors use multiple stepping stones, often innocent
systems that have been compromised, to mask the true source. As such, this thesis
identifies that no publicly known previous work has been deployed on a wide-scale basis
in the Internet infrastructure.
This research investigates the use of an often overlooked tool for attribution: cyber de-
ception. The main contribution of this work is a significant advancement in the field of
deception and honeypots as technical attribution techniques. Specifically, the design and
implementation of two novel honeypot approaches; i) Deception Inside Credential Engine
(DICE), that uses policy and honeytokens to identify adversaries returning from different
origins and ii) Adaptive Honeynet Framework (AHFW), an introspection and adaptive
honeynet framework that uses actor-dependent triggers to modify the honeynet envi-
ronment, to engage the adversary, increasing the quantity and diversity of interactions.
The two approaches are based on a systematic review of the technical attribution litera-
ture that was used to derive a set of requirements for honeypots as technical attribution
techniques. Both approaches lead the way for further research in this field
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Traffic engineering multi-layer optimization for wireless mesh network transmission a campus network routing protocol transmission performance inhancement
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityThe wireless mesh network is a potential network for the future due to its excellent inherent characteristic for dynamic self-healing, self-configuration and self-organization. It also has the advantage of easy interoperability networking and the ability to form multi-linked ad-hoc networks. It has a decentralized topology, is cheap and highly scalable. Furthermore, its ease in deployment and easy maintenance are other inherent networking qualities. These aforementioned qualities of the wireless mesh network bring advantages to transmission capability of heterogeneous networks. However, transmissions in wireless mesh network create comparative performance based challenges such as congestion, load-balancing, scalability over increasing networks and coverage capacity. Consequently, these challenges and problems in the routing and switching of packets in the wireless mesh network routing protocols led to a proposal on the resolution of these failures with a combination algorithm and a management based security for the network and its transmitted packets. There are equally contentious services like reliability of the network and quality of service for real-time multimedia traffic flows with other challenges such as path computation and selection in the wireless mesh network.
This thesis is therefore a cumulative proposal to the resolution of the outlined challenges and open research areas posed by using wireless mesh network routing protocol. It advances the resolution of these challenges in the mesh environment using a hybrid optimization – traffic engineering, to increase the effectiveness and the reliability of the network. It also proffers a cumulative resolution of the diverse contributions on wireless mesh network routing protocol and transmission. Adaptation and optimization are carried out on the wireless mesh network designed network using traffic engineering mechanism and technique. The research examines the patterns of mesh packet transmission and evaluates the challenges and failures in the mesh network packet transmission. It develops a solution based algorithm for resolutions and proposes the traffic engineering based solution.. These resultant performances and analysis are usually tested and compared over wireless mesh IEEE802.11n or other older proposed documented solution.
This thesis used a carefully designed campus mesh network to show a comparative evaluation of an optimal performance of the mesh nodes and routers over a normal IEE802.11n based wireless domain network to show differentiation by optimization using the created algorithms. Furthermore, the indexes of performance being the metric are used to measure the utility and the reliability, including capacity and throughput at the destination during traffic engineered transmission. In addition, the security of these transmitted data and packets are optimized under a traffic engineered technique. Finally, this thesis offers an understanding to the security contribution using traffic engineering resolution to create a management algorithm for processing and computation of the wireless mesh networks security needs. The results of this thesis confirmed, completed and extended the existing predictions with real measurement
Reliable, resilient and sustainable water management: The Safe & SuRe approach
Global threats such as climate change, population growth, and rapid urbanization pose a huge future challenge to water management, and, to ensure the ongoing reliability, resilience and sustainability of service provision, a paradigm shift is required. This paper presents an overarching framework that supports the development of strategies for reliable provision of services while explicitly addressing the need for greater resilience to emerging threats, leading to more sustainable solutions. The framework logically relates global threats, the water system (in its broadest sense), impacts on system performance, and social, economic, and environmental consequences. It identifies multiple opportunities for intervention, illustrating how mitigation, adaptation, coping, and learning each address different elements of the framework. This provides greater clarity to decision makers and will enable better informed choices to be made. The framework facilitates four types of analysis and evaluation to support the development of reliable, resilient, and sustainable solutions: “top‐down,” “bottom‐up,” “middle based,” and “circular” and provides a clear, visual representation of how/when each may be used. In particular, the potential benefits of a middle‐based analysis, which focuses on system failure modes and their impacts and enables the effects of unknown threats to be accounted for, are highlighted. The disparate themes of reliability, resilience and sustainability are also logically integrated and their relationships explored in terms of properties and performance. Although these latter two terms are often conflated in resilience and sustainability metrics, the argument is made in this work that the performance of a reliable, resilient, or sustainable system must be distinguished from the properties that enable this performance to be achieved
Intimate Partner Violence in Immigrant and Refugee Communities: Challenges, Promising Practices and Recommendations
Reviews research on intimate partner violence in immigrant and refugee communities and examines victims' needs, challenges for agencies, and promising practices for prevention. Makes recommendations for funders, service providers, and policy makers
Strategic Culture as the Basis for Military Adaptive Capacity: Overcoming battlefield technological surprises
The ability of a military to respond to environmental changes rather than rigidly adhere to previously defined concepts of operation is paramount to overcoming unforeseen battlefield technological challenges. A force with the greater capacity for learning and adaptation will possess significant advantages in overcoming unforeseen challenges. However, it is unclear as to what determines the flexibility or adaptive capacity of a military during military engagements. To address this issue, this study focuses on intra- war adaptation as a product of a military’s strategic culture in overcoming enemy technological surprises. The work demonstrates the symbiotic relationship between strategic culture and adaptability that ultimately determines how effectively a force will respond to unforeseen battlefield challenges. For this reason, strategic culture is indispensable in explaining why militaries may continue to act in ways that are incongruous with prevailing operational circumstances while others are adept at responding to Clausewitzian fog and friction
DYNAMIC MECHANICAL BEHAVIOR OF MAGNESIUM ALLOYS UNDER SHOCK LOADING CONDITION
The use of magnesium and its alloys, as the lightest structural materials, to decrease the weight, improve the fuel efficiency and reduce the greenhouse gas emissions has significantly increased in the automotive and aerospace industries in recent years. However, magnesium alloys are commonly used as die casting products. The current application of wrought magnesium alloy products is limited because of their poor ductility at room temperature due to the formation of a strong texture and restricted active deformation modes in wrought magnesium products. Moreover, to support the application of magnesium alloys in automobile and airplane components, their dynamic mechanical response must be determined to evaluate their behavior during impact events such as car crash and bird strike in airplanes. Therefore, in this research study, the dynamic mechanical behavior of magnesium alloys at high strain rates was investigated. The effects of initial texture, composition, strain rate and grain size on the deformation mechanism were also determined.
Split Hopkinson Pressure Bar was used to investigate the dynamic mechanical behavior of the magnesium alloys. Texture analysis on the alloy prior and after shock loading was done using X-ray diffraction. Scanning electron microscopy was used to study the microstructural evolution in the alloys before and after shock loading. Chemical analysis and phase identification were done by energy dispersive spectroscopy and X-ray diffraction analysis, respectively. Additionally, twinning type and distribution was determined by means of orientation imaging microscopy whereas dislocation types and distribution was determined using transmission electron microscopy. A visco-plastic self-consistent simulation was used to corroborate the experimental textures and possible deformation mechanisms.
The dynamic mechanical behavior of cast AZ and AE magnesium alloys with different chemistries was investigated at strain rates ranging between 800 to 1400 s-1 to determine the effects of composition on the response of the alloys to shock loading. It was found that an increase in the aluminum content of the AZ alloys increased the volume fraction of β-Mg17Al12 and Al4Mn phases, strength and strain hardening but, on the other hand, decreased the ductility and twinning fraction, particularly extension twinning fraction, for all the investigated strain rates. In addition, increasing the strain rate resulted in considerable increase in strength of the alloys. Texture measurements showed that shock loading of the AE alloys resulted in development of a stronger (00.2) basal texture in samples with higher content of yttrium at the investigated strain rates. Increasing the yttrium content of the cast AE alloys decreased twinning fraction but increased dislocation density and volume fraction of the Al2Y second phase. As a result, the tensile strength and ductility of the alloys increased which is an interesting result for high-strain rate applications of AE alloys in comparison to AZ alloys.
The dynamic mechanical behavior of rolled AZ31B and WE43 magnesium alloys were also studied at strain rates ranging between 600 to 1400 s-1. A strong (00.2) basal texture was observed in all shock loaded AZ31B samples. It was also observed that increasing the strain rate led to an increase in strength and ductility, but to a decrease in twinning fraction. A high degree of mechanical anisotropy was found for all investigated strain rates so that the lowest strength was registered for the samples cut along the direction parallel to the rolling direction. Furthermore, it was found that at high strain rates, fine-grained AZ31B alloy exhibits better ductility and strength compared to coarse-grained alloy. However, the hardening rate of coarse-grained alloy was higher.
In the case of rolled WE43 alloy, it was found that the strength and ductility increased and twinning fraction decreased with increase in strain rate. Furthermore, another effect of increase in strain rate was the higher activation of pyramidal slip systems. In addition, degree of stress and strain anisotropy is low particularly at higher strain rates, which is mainly related to the weak initial texture of the samples due to the presence of rare earth elements. Furthermore, strength and ductility were found to decrease with increasing grain size, while twinning fraction, activity of double and contraction twins and strain hardening rate increase with increasing grain size. In both AZ31B and WE43 alloy, the presence of dislocations was confirmed at high strain rates using ‘g.b’ analysis confirming activation of pyramidal slip systems during dynamic shock loading
Mechanism of failure by hydrogen-induced cracking in pipeline steels
Pipeline steels that carry oil and natural gas in severe environments suffer from two important modes of failure: stress corrosion cracking (SCC) and hydrogen-induced cracking (HIC). The SCC has been studied extensively in the literature; however, HIC phenomenon in pipeline steels is less investigated by researchers. Nevertheless, HIC is recognized as the most important damage mode in sour environment. Hydrogen atoms produced due to surface corrosion of the steel diffuse into it through microstructural defects. When a critical amount of hydrogen is accumulated in such defects, HIC cracks initiate and propagate. The main objectives of this thesis are to find the HIC crack nucleation and propagation sites, evaluate a role of texture and grain boundary character distribution in crack growth and finally establish the effect of different microstructural parameters contributing to the HIC related failure in pipeline steel.
In this thesis, HIC standard test and electrochemical hydrogen-charging experiments were used to induce HIC cracks in pipeline steels. HIC cracks at the cross section of tested samples were observed using scanning electron microscope (SEM). The SEM observations clearly indicate that the investigated X60 and X70 steels are susceptible to HIC while the X60SS steel showed a higher resistance to HIC. This experiment also proved that the X70 steel has higher susceptibility to HIC than the other investigated steel. Energy dispersive spectroscopic (EDS) analyses indicated that two types of inclusion namely manganese sulfide and carbonitiride precipitates serve as crack nucleation sites. HIC cracks were observed to propagate at the center of cross section where the segregation of some elements such as carbon and manganese occurred.
Moreover, two other experiments were carried out in order to evaluate the capability of pipeline steels for hydrogen-trapping. The first test, hydrogen-permeation experiment, showed that all pipeline steel specimens, such as X70, X60 and X60SS steels, contain both reversible and irreversible hydrogen traps. However, the density of traps at the center of cross section was higher than other regions in all tested specimens. The hydrogen-discharging experiments also showed that all specimens keep a considerable amount of hydrogen inside their traps. The hydrogen traps, based on their binding energy with the metal matrix, are categorized as reversible (weak) and irreversible (strong) traps and the roles of each type of traps are explained.
Electron backscatter diffraction (EBSD) measurements were done along the HIC crack in X70 steel after standard HIC test. The results showed that the {100} texture was strong while the {111} texture was weak. Some special texture components, such as the {110}, {332} and {112}, were observed after the HIC crack-stoppage. EBSD results also documented that fine grain colonies were prone to intergranular HIC crack propagation and IPF and PF, calculated in both sides of HIC cracks, showed the preferences of ND|| orientation.
Both susceptible X60 and non-susceptible X60SS steel to HIC were compared based on the EBSD results. It was observed that the high amount of recrystallization fraction with no stored energy is one of the main reasons for a higher HIC resistance of X60SS steel to HIC. Moreover, Kernel Average Misorientation (KAM) data showed that the deformation is more concentrated in the as-received and HIC tested X60 specimens.
The effect of hydrogen-charging during tensile/fatigue loading of X60SS steel was studied and it was observed that some HIC cracks at the cross section of X60SS steel were appeared after hydrogen-charging at stresses below the yield stress.
Experiments were carried out to understand the effect of cold-rolling and annealing on HIC susceptibility in pipeline steels. The results documented that the {100} dominant texture is more pronounced in 50% and 90% cold-rolled and annealed specimens. The effect of different factors such as KAM degree and recrystallized fraction affecting HIC susceptibility on cold-rolled and annealed specimens was investigated. The obtained results showed that the cold-rolling and annealing process may not be considered as an effective method to increase HIC resistance in pipeline steels
Improving Dependability of Networks with Penalty and Revocation Mechanisms
Both malicious and non-malicious faults can dismantle computer networks. Thus, mitigating faults at various layers is essential in ensuring efficient and fair network resource utilization. In this thesis we take a step in this direction and study several ways to deal with faults by means of penalties and revocation mechanisms in networks that are lacking a centralized coordination point, either because of their scale or design.
Compromised nodes can pose a serious threat to infrastructure, end-hosts and services. Such malicious elements can undermine the availability and fairness of networked systems. To deal with such nodes, we design and analyze protocols enabling their removal from the network in a fast and a secure way. We design these protocols for two different environments. In the former setting, we assume that there are multiple, but independent trusted points in the network which coordinate other nodes in the network. In the latter, we assume that all nodes play equal roles in the network and thus need to cooperate to carry out common functionality. We analyze these solutions and discuss possible deployment scenarios.
Next we turn our attention to wireless edge networks. In this context, some nodes, without being malicious, can still behave in an unfair manner. To deal with the situation, we propose several self-penalty mechanisms. We implement the proposed protocols employing a commodity hardware and conduct experiments in real-world environments. The analysis of data collected in several measurement rounds revealed improvements in terms of higher fairness and throughput. We corroborate the results with simulations and an analytic model. And finally, we discuss how to measure fairness in dynamic settings, where nodes can have heterogeneous resource demands
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