Risk-informed thinking in airports: the application of business continuity management in airport infrastructure

Airports worldwide represent key forms of critical infrastructure in addition to serving as nodes in the international aviation network. While the continued operation of airports is critical to the functioning of reliable air passenger and freight transportation, these infrastructure systems face a number of sources of disturbance that threaten their operational viability. Recent examples of high magnitude events include the eruption of Iceland’s Eyjafjallajokull volcano eruption (Folattau and Schofield 2010), the failure of multiple systems at the opening of Heathrow’s Terminal 5 (Brady and Davies 2010) and the Glasgow airport 2007 terrorist attack (Crichton 2008). While these newsworthy events do occur, a multitude of lower-level more common disturbances also have the potential to cause significant discontinuity to airport operations. Regional airports face a unique set of challenges, particularly in a nation like Australia where they serve to link otherwise remote and isolated communities to metropolitan hubs (Wheeler 2005), often without the resources and political attention received by larger capital city airports. This paper discusses conceptual relationships between Business Continuity Management (BCM) and High Reliability Theory, and proposes BCM as an appropriate risk-based management process to ensure continued airport operation in the face of uncertainty. In addition, it argues that that correctly implemented BCM can lead to highly reliable organisations. This is framed within the broader context of critical infrastructures and the need for adequate crisis management approaches suited to their unique requirements (Boin and McConnell 2007).

Crowdsourcing information systems : a systems theory perspective

Crowdsourcing harnesses the potential of large and open networks of people. It is a relatively new phenomenon and attracted substantial interest in practice. Related research, however, lacks a theoretical foundation. We propose a system-theoretical perspective on crowdsourcing systems to address this gap and illustrate its applicability by using it to classify crowdsourcing systems. By deriving two principal dimensions from theory, we identify four fundamental types of crowdsourcing systems that help to distinguish important features of such systems. We analyse their respective characteristics and discuss implications and requirements for various aspects related to the design of such systems. Our results demonstrate that systems theory can inform the study of crowdsourcing systems. The identified system types and the implications on their design may prove useful for researchers to frame future studies and for practitioners to identify the right crowdsourcing systems for a particular purpose.

Capstones : transitions and professional identity

The literature identifies transition as a key objective for capstone experiences. Capstones should take account of the particular needs of final year students by assisting them to transition from their student to their professional identity. The authors are currently completing an Australian Learning and Teaching Council (ALTC) funded project, “Curriculum Renewal in Legal Education: articulating final year curriculum design principles and a final year program”, which seeks to achieve curriculum renewal for legal education in the Australian context through the articulation of a set of curriculum design principles for the final year and the design of a transferable model for an effective final year program. The project has investigated the contemporary role of capstones in assisting transition out by reviewing the relevant literature and considering feedback from a project reference group, a final year student focus group and a recent graduate’s focus group. Analysis of this extensive research- and evidence-base suggests that capstone experiences should support transition through: • Assisting students to develop a sense of professional identity; • Consolidating students’ lifelong learning skills; • Providing opportunities for consolidation of career development and planning processes; • Enabling students to enhance professional skills and competencies; and • Preparing students as ethical citizens and leaders. This paper will examine the role of capstones in assisting students to transition to their professional identity and will propose learning and teaching approaches and assessment of learning methods that support transition out.

Negotiation theory and application in the business environment

This chapter introduces different theoretical approaches to negotiation and provides an explanation of these differing frameworks. While the action of a negotiation centres on the background research undertaken and what happens at the negotiation table, there is a need to know what principles and assumptions are informing these activities. Theories offer a way of understanding the underlying structures, processes and relationships of negotiation. Further, negotiation theories also assist with focusing attention on the 'basis of the bargain' and provide a standpoint from which to judge offers and counter-offers during the negotiation.

Addressing bullying and cyberbullying in schools: Translating theory into practice

Overviews of research are clear that bullying occurs in every school, and that there are significant negative physical and mental health outcomes associated with it (Beaty and Alexeyev, 2008; Carter, 2011). As such, it is imperative to develop successful intervention strategies to help students cope with bullying, including the emergent form of cyberbullying. Research suggests, however, that students have a very limited repertoire of strategies for dealing with bullying generally (Owens, Shute, and Slee, 2004). In this paper the authors outline what is currently known about bullying, including cyberbullying, its impact on students, how theory can assist in developing interventions to assist and support students to cope with bullying, and some of the implications for schools.

Different kinds of openings of Luhmann's systems theory: A reply to la Cour et al

Various researchers have called for an 'opening up' of Luhmann's systems theory. We take this short paper as an occasion for a critical reflection on the necessity, existence and possibilities of such an opening. We start by pointing out the inherent openness of Luhmann's theory, and, based on this, discuss three kinds of openings: the international opening, the theoretical opening and the empirical opening. With regard to the latter, we distinguish three general options of using Luhmann's theory for empirical research. Copyright © 2007 SAGE.

Towards an orchestration theory in business transformation management (research in progress)

Business transformations are large-scale organisational change projects that, evidence suggests, are often unsuccessful. This study aims to develop a conceptual model that explains how management services that are required for a business transformation are orchestrated during such a initiative. We classify management services such as (but not limited to) change management, risk management, IT management, financial management, program management and so forth as bearing transformational and/or transactional capabilities in a transformation initiative. We then draw upon three principles of musical composition, namely melody, harmony and rhythm, and illustrate how they apply to the orchestration of management services in the management of business transformations. In order to illustrate our emerging model, we examine the case of Malaysia Airlines, who have managed to successfully turnaround the near-bankrupt organisation beyond survival. We demonstrate how the notions of melody, harmony and rhythm can be used to describe their endeavour. We conclude by discussing next steps of our research.

After Sex? On Writing since Queer Theory, edited by Janet Halley and Andrew Parker [Review]

In its earliest and simplest form queer theory proposes that sexual identity is not essential, but socially constructed, and understandings of identity, gender and sexuality are constructed differently at different times and in different places. Queer theory aims to challenge normative understandings of sex, sexuality and gender, and also normative concepts of knowledge and being. Since its inception, queer theory has been taken up by a number of disciplines as an analytical framework. These include cultural geography, education studies, film studies and sociology. In the last decade queer theory has been used to consider citizenship, diasporas and post colonial experiences. A queer theoretical perspective has also been used to analyse emotions, the Death Drive, phenomenology, and disability. As queer theory enters its third decade Janet Halley and Andrew Parker ask what is after sex? ‘What has queer theory become now that it has a past?’

Value co-creation in social marketing wellness services

Customer perceived value is concerned with the experiences of consumers when using a service and is often referred to in the context of service provision or on the basis of service quality (Auh, et al., 2007; Chang, 2008; Jackson, 2007; Laukkanen, 2007; Padgett & Mulvey, 2007; Shamdasani, Mukherjee & Malhotra, 2008). Understanding customer perceived value has benefits for social marketing and allows scholars and practitioners alike to identify why consumers engage in positive social behaviours through the use of services. Understanding consumers’ use of wellness services in particular is important, because the use of wellness services demonstrates the fulfilment of social marketing aims; performing pro-active, positive social behaviours that are of benefit to the individual and to society (Andreasen, 1994). As consumers typically act out of self-interest (Rothschild, 1999), this research posits that a value proposition must be made to consumers in order to encourage behavioural change. Thus, this research seeks to identify how value is created for consumers of wellness services in social marketing. This results in the overall research question of this research: How is value created in social marketing wellness services? A traditional method towards understanding value has been the adoption of an economic approach, which considers the utility gained and where value is a direct outcome of a cost-benefit analysis (Payne & Holt, 1999). However, there has since been a shift towards the adoption of an experiential approach in understanding value. This experiential approach considers the consumption experience of the consumer which extends beyond the service exchange and includes pre- and post-consumption stages (Russell-Bennett, Previte & Zainuddin, 2009). As such, this research uses an experiential approach to identify the value that exists in social marketing wellness services. Four dimensions of value have been commonly conceptualised and identified in the commercial marketing literature; functional, emotional, social, and altruistic value (Holbrook, 1994; Sheth, Newman & Gross, 1991; Sweeney & Soutar, 2001). It is not known if these value dimensions also exist in social marketing. In addition, sources of value said to influence value dimensions have been conceptualised in the literature. Sources of value such as information, interaction, environment, service, customer co-creation, and social mandate have been conceptually identified both in the commercial and social marketing literature (Russell-Bennet, Previte & Zainuddin, 2009; Smith & Colgate, 2007). However, it is not clear which sources of value contribute to the creation of value for users of wellness services. Thus, this research seeks to explore these relationships. This research was conducted using a wellness service context, specifically breast cancer screening services. The primary target consumer of these services is women aged 50 to 69 years old (inclusive) who have never been diagnosed with breast cancer. It is recommended that women in this target group have a breast screen every 2 years in order to achieve the most effective medical outcomes from screening. A two-study mixed method approach was utilised. Study 1 was a qualitative exploratory study that analysed individual-depth interviews with 25 information-rich respondents. The interviews were transcribed verbatim and analysed using NVivo 8 software. The qualitative results provided evidence of the existence of the four value dimensions in social marketing. The results also allowed for the development of a typology of experiential value by synthesising current understanding of the value dimensions, with the activity aspects of experiential value identified by Holbrook (1994) and Mathwick, Malhotra and Rigdon (2001). The qualitative results also provided evidence for the existence of sources of value in social marketing, namely information, interaction, environment and consumer participation. In particular, a categorisation of sources of value was developed as a result of the findings from Study 1, which identify organisational, consumer, and third party sources of value. A proposed model of value co-creation and a set of hypotheses were developed based on the results of Study 1 for further testing in Study 2. Study 2 was a large-scale quantitative confirmatory study that sought to test the proposed model of value co-creation and the hypotheses developed. An online-survey was administered Australia-wide to women in the target audience. A response rate of 20.1% was achieved, resulting in a final sample of 797 useable responses after removing ineligible respondents. Reliability and validity analyses were conducted on the data, followed by Exploratory Factor Analysis (EFA) in PASW18, followed by Confirmatory Factor Analysis (CFA) in AMOS18. Following the preliminary analyses, the data was subject to Structural Equation Modelling (SEM) in AMOS18 to test the path relationships hypothesised in the proposed model of value creation. The SEM output revealed that all hypotheses were supported, with the exception of one relationship which was non-significant. In addition, post hoc tests revealed seven further significant non-hypothesised relationships in the model. The quantitative results show that organisational sources of value as well as consumer participation sources of value influence both functional and emotional dimensions of value. The experience of both functional and emotional value in wellness services leads to satisfaction with the experience, followed by behavioural intentions to perform the behaviour and use the service again. One of the significant non-hypothesised relationships revealed that emotional value leads to functional value in wellness services, providing further empirical evidence that emotional value features more prominently than functional value for users of wellness services. This research offers several contributions to theory and practice. Theoretically, this research addresses a gap in the literature by using social marketing theory to provide an alternative method of understanding individual behaviour in a domain that has been predominantly investigated in public health. This research also clarifies the concept of value and offers empirical evidence to show that value is a multi-dimensional construct with separate and distinct dimensions. Empirical evidence for a typology of experiential value, as well as a categorisation of sources of value is also provided. In its practical contributions, this research identifies a framework that is the value creation process and offers health services organisations a diagnostic tool to identify aspects of the service process that facilitate the value creation process.

A rebirth of physical activity in parents : applying a theory-based approach

Physical inactivity is a serious concern both nationally and internationally. Despite the numerous benefits of performing regular physical activity, many individuals lead sedentary lifestyles. Of concern, though, is research showing that some population sub-groups are less likely to be active, such as parents of young children. Although there is a vast amount of research dedicated to understanding people.s physical activity-related behaviours, there is a paucity of research examining those factors that influence parental physical activity. More importantly, research applying theoretical models to understand physical activity decision-making among this at-risk population is limited. Given the current obesity epidemic, the decline in physical activity with parenthood, and the many social and health benefits associated with regular physical activity, it is important that adults with young children are sufficiently active. In light of the dearth of research examining parental physical activity and the scant research applying a theory-based approach to gain this understanding, the overarching aim of the current program of research was to adopt a mixed methods approach as well as use sound theoretical frameworks to understand the regular physical activity behaviour of mothers and fathers with young children. This program of research comprised of three distinct stages: a qualitative stage exploring individual, social, and psychological factors that influence parental regular physical activity (Stage 1); a quantitative stage identifying the important predictors of parental regular physical activity intentions and behaviour using sound theoretical frameworks and testing a single-item measure for assessing parental physical activity behaviour (Stage 2); and a qualitative stage exploring strategies for an intervention program aimed at increasing parental regular physical activity (Stage 3). As a thesis by publication, eight papers report the findings of this program of research; these papers are presented according to the distinct stages of investigation that guided this program of research. Stage One of the research program comprised a qualitative investigation using a focus group/interview methodology with parents of children younger than 5 years of age (N = 40; n = 21 mothers, n = 19 fathers) (Papers 1, 2, and 3). Drawing broadly on a social constructionist approach (Paper 1), thematic analytic methods revealed parents. understandings of physical activity (e.g., requires effort), patterns of physical activity-related behaviours (e.g., grab it when you can, declining physical activity habits), and how constructions of social role expectations might influence parents. physical activity decision making (e.g., creating an active family culture, guilt and selfishness). Drawing on the belief-based framework of the TPB (Paper 2), thematic content analytic methods revealed parents. commonly held beliefs about the advantages (e.g., improves parenting practices), disadvantages (e.g., interferes with commitments), barriers (e.g., time), and facilitators (e.g., social support) to performing regular physical activity. Parents. normative beliefs about social approval from important others or groups (e.g., spouse/partner) were also identified. Guided by theories of social support, Paper Three identified parents. perceptions about the specific social support dimensions that influence their physical activity decision making. Thematic content analysis identified instrumental (e.g., providing childcare, taking over chores), emotional (e.g., encouragement, companionship), and informational support (e.g., ideas and advice) as being important to the decision-making of parents in relation to their regular physical activity behaviour. The results revealed also that having support for being active is not straightforward (e.g., guilt-related issues inhibited the facilitative nature of social support for physical activity). Stage Two of the research program comprised a quantitative examination of parents. physical activity intentions and behaviour (Papers 4, 5, 6, and 7). Parents completed an extended TPB questionnaire at Time 1 (N = 580; n = 288 mothers, n = 292 fathers) and self-reported their physical activity at Time 2, 1 week later (N = 458; n = 252 mothers, n = 206 fathers). Paper Four revealed key behavioural (e.g., improving parenting practices), normative (e.g., people I exercise with), and control (e.g., lack of time) beliefs as significant independent predictors of parental physical activity. A test of the TPB augmented to include the constructs of self-determined motivation and planning was assessed in Paper Five. The findings revealed that the effect of self-determined motivation on intention was fully mediated by the TPB variables and the impact of intention on behaviour was partially mediated by the planning variables. Slight differences in the model.s motivational sequence between the sexes were also noted. Paper Six investigated, within a TPB framework, a range of social influences on parents. intentions to be active. For both sexes, attitude, perceived behavioural control, group norms, friend general support, and an active parent identity predicted intentions, with subjective norms and family support further predicting mothers. intentions and descriptive norms further predicting fathers. intentions. Finally, the measurement of parental physical activity was investigated in Paper Seven of Stage Two. The results showed that parents are at risk of low levels of physical activity, with the findings also revealing validation support for a brief single-item physical activity measure. Stage Three of the research program comprised a qualitative examination of parents. (N = 12; n = 6 mothers, n = 6 fathers) ideas for strategies that may be useful for developing and delivering an intervention program aimed at increasing parental physical activity (Paper 8). Parents revealed a range of strategies for what to include in a physical activity intervention designed for parents of young children. For example, parents identified persuasion and information type messages, problem-solving strategies that engage parents in generating a priority list of their lifestyle commitments, and behavioural modification techniques such as goal setting and incentives. Social intervention strategies (e.g., social comparison, counselling) and environmental approaches (e.g., community-based integrative parent/child programs) were also identified as was a skill-based strategy in helping parents generate a flexible life/family plan. Additionally, a range of strategies for how to best deliver a parental physical activity intervention was discussed. Taken as a whole, Paper Eight found that adopting a multifaceted approach in both the design and implementation of a resultant physical activity intervention may be useful in helping to increase parental physical activity. Overall, this program of research found support for parents as a unique group who hold both similar and distinctive perceptions about regular physical activity to the general adult population. Thus, these findings highlight the importance of targeting intervention strategies for parents of young children. Additionally, the findings suggest that it might also be useful to tailor some messages specifically to each sex. Effective promotion of physical activity in parents of young children is essential given the low rate of activity in this population. Results from this program of research highlight parents as an at-risk group for inactivity and provide an important first step in identifying the factors that influence both mothers. and fathers. physical activity decision making. These findings, in turn, provide a foundation on which to build effective intervention programs aimed at increasing parents. regular physical activity which is essential for ensuring the health and well-being of parents with young children.

The Measurement of Information System Use: Preliminary Considerations

DeLone and McLean (1992, p. 16) argue that the concept of “system use” has suffered from a “too simplistic definition.” Despite decades of substantial research on system use, the concept is yet to receive strong theoretical scrutiny. Many measures of system use and the development of measures have been often idiosyncratic and lack credibility or comparability. This paper reviews various attempts at conceptualization and measurement of system use and then proposes a re-conceptualization of it as “the level of incorporation of an information system within a user’s processes.” The definition is supported with the theory of work systems, system, and Key-User-Group considerations. We then go on to develop the concept of a Functional- Interface-Point (FIP) and four dimensions of system usage: extent, the proportion of the FIPs used by the business process; frequency, the rate at which FIPs are used by the participants in the process; thoroughness, the level of use of information/functionality provided by the system at an FIP; and attitude towards use, a set of measures that assess the level of comfort, degree of respect and the challenges set forth by the system. The paper argues that the automation level, the proportion of the business process encoded by the information system has a mediating impact on system use. The article concludes with a discussion of some implications of this re-conceptualization and areas for follow on research.

Fuzzy methods for analysis of microarrays and networks

Bioinformatics involves analyses of biological data such as DNA sequences, microarrays and protein-protein interaction (PPI) networks. Its two main objectives are the identification of genes or proteins and the prediction of their functions. Biological data often contain uncertain and imprecise information. Fuzzy theory provides useful tools to deal with this type of information, hence has played an important role in analyses of biological data. In this thesis, we aim to develop some new fuzzy techniques and apply them on DNA microarrays and PPI networks. We will focus on three problems: (1) clustering of microarrays; (2) identification of disease-associated genes in microarrays; and (3) identification of protein complexes in PPI networks. The first part of the thesis aims to detect, by the fuzzy C-means (FCM) method, clustering structures in DNA microarrays corrupted by noise. Because of the presence of noise, some clustering structures found in random data may not have any biological significance. In this part, we propose to combine the FCM with the empirical mode decomposition (EMD) for clustering microarray data. The purpose of EMD is to reduce, preferably to remove, the effect of noise, resulting in what is known as denoised data. We call this method the fuzzy C-means method with empirical mode decomposition (FCM-EMD). We applied this method on yeast and serum microarrays, and the silhouette values are used for assessment of the quality of clustering. The results indicate that the clustering structures of denoised data are more reasonable, implying that genes have tighter association with their clusters. Furthermore we found that the estimation of the fuzzy parameter m, which is a difficult step, can be avoided to some extent by analysing denoised microarray data. The second part aims to identify disease-associated genes from DNA microarray data which are generated under different conditions, e.g., patients and normal people. We developed a type-2 fuzzy membership (FM) function for identification of diseaseassociated genes. This approach is applied to diabetes and lung cancer data, and a comparison with the original FM test was carried out. Among the ten best-ranked genes of diabetes identified by the type-2 FM test, seven genes have been confirmed as diabetes-associated genes according to gene description information in Gene Bank and the published literature. An additional gene is further identified. Among the ten best-ranked genes identified in lung cancer data, seven are confirmed that they are associated with lung cancer or its treatment. The type-2 FM-d values are significantly different, which makes the identifications more convincing than the original FM test. The third part of the thesis aims to identify protein complexes in large interaction networks. Identification of protein complexes is crucial to understand the principles of cellular organisation and to predict protein functions. In this part, we proposed a novel method which combines the fuzzy clustering method and interaction probability to identify the overlapping and non-overlapping community structures in PPI networks, then to detect protein complexes in these sub-networks. Our method is based on both the fuzzy relation model and the graph model. We applied the method on several PPI networks and compared with a popular protein complex identification method, the clique percolation method. For the same data, we detected more protein complexes. We also applied our method on two social networks. The results showed our method works well for detecting sub-networks and give a reasonable understanding of these communities.

Multifractal characterisation and analysis of complex networks

Complex networks have been studied extensively due to their relevance to many real-world systems such as the world-wide web, the internet, biological and social systems. During the past two decades, studies of such networks in different fields have produced many significant results concerning their structures, topological properties, and dynamics. Three well-known properties of complex networks are scale-free degree distribution, small-world effect and self-similarity. The search for additional meaningful properties and the relationships among these properties is an active area of current research. This thesis investigates a newer aspect of complex networks, namely their multifractality, which is an extension of the concept of selfsimilarity. The first part of the thesis aims to confirm that the study of properties of complex networks can be expanded to a wider field including more complex weighted networks. Those real networks that have been shown to possess the self-similarity property in the existing literature are all unweighted networks. We use the proteinprotein interaction (PPI) networks as a key example to show that their weighted networks inherit the self-similarity from the original unweighted networks. Firstly, we confirm that the random sequential box-covering algorithm is an effective tool to compute the fractal dimension of complex networks. This is demonstrated on the Homo sapiens and E. coli PPI networks as well as their skeletons. Our results verify that the fractal dimension of the skeleton is smaller than that of the original network due to the shortest distance between nodes is larger in the skeleton, hence for a fixed box-size more boxes will be needed to cover the skeleton. Then we adopt the iterative scoring method to generate weighted PPI networks of five species, namely Homo sapiens, E. coli, yeast, C. elegans and Arabidopsis Thaliana. By using the random sequential box-covering algorithm, we calculate the fractal dimensions for both the original unweighted PPI networks and the generated weighted networks. The results show that self-similarity is still present in generated weighted PPI networks. This implication will be useful for our treatment of the networks in the third part of the thesis. The second part of the thesis aims to explore the multifractal behavior of different complex networks. Fractals such as the Cantor set, the Koch curve and the Sierspinski gasket are homogeneous since these fractals consist of a geometrical figure which repeats on an ever-reduced scale. Fractal analysis is a useful method for their study. However, real-world fractals are not homogeneous; there is rarely an identical motif repeated on all scales. Their singularity may vary on different subsets; implying that these objects are multifractal. Multifractal analysis is a useful way to systematically characterize the spatial heterogeneity of both theoretical and experimental fractal patterns. However, the tools for multifractal analysis of objects in Euclidean space are not suitable for complex networks. In this thesis, we propose a new box covering algorithm for multifractal analysis of complex networks. This algorithm is demonstrated in the computation of the generalized fractal dimensions of some theoretical networks, namely scale-free networks, small-world networks, random networks, and a kind of real networks, namely PPI networks of different species. Our main finding is the existence of multifractality in scale-free networks and PPI networks, while the multifractal behaviour is not confirmed for small-world networks and random networks. As another application, we generate gene interactions networks for patients and healthy people using the correlation coefficients between microarrays of different genes. Our results confirm the existence of multifractality in gene interactions networks. This multifractal analysis then provides a potentially useful tool for gene clustering and identification. The third part of the thesis aims to investigate the topological properties of networks constructed from time series. Characterizing complicated dynamics from time series is a fundamental problem of continuing interest in a wide variety of fields. Recent works indicate that complex network theory can be a powerful tool to analyse time series. Many existing methods for transforming time series into complex networks share a common feature: they define the connectivity of a complex network by the mutual proximity of different parts (e.g., individual states, state vectors, or cycles) of a single trajectory. In this thesis, we propose a new method to construct networks of time series: we define nodes by vectors of a certain length in the time series, and weight of edges between any two nodes by the Euclidean distance between the corresponding two vectors. We apply this method to build networks for fractional Brownian motions, whose long-range dependence is characterised by their Hurst exponent. We verify the validity of this method by showing that time series with stronger correlation, hence larger Hurst exponent, tend to have smaller fractal dimension, hence smoother sample paths. We then construct networks via the technique of horizontal visibility graph (HVG), which has been widely used recently. We confirm a known linear relationship between the Hurst exponent of fractional Brownian motion and the fractal dimension of the corresponding HVG network. In the first application, we apply our newly developed box-covering algorithm to calculate the generalized fractal dimensions of the HVG networks of fractional Brownian motions as well as those for binomial cascades and five bacterial genomes. The results confirm the monoscaling of fractional Brownian motion and the multifractality of the rest. As an additional application, we discuss the resilience of networks constructed from time series via two different approaches: visibility graph and horizontal visibility graph. Our finding is that the degree distribution of VG networks of fractional Brownian motions is scale-free (i.e., having a power law) meaning that one needs to destroy a large percentage of nodes before the network collapses into isolated parts; while for HVG networks of fractional Brownian motions, the degree distribution has exponential tails, implying that HVG networks would not survive the same kind of attack.

Anonymity and one-way authentication in key exchange protocols

Key establishment is a crucial cryptographic primitive for building secure communication channels between two parties in a network. It has been studied extensively in theory and widely deployed in practice. In the research literature a typical protocol in the public-key setting aims for key secrecy and mutual authentication. However, there are many important practical scenarios where mutual authentication is undesirable, such as in anonymity networks like Tor, or is difficult to achieve due to insufficient public-key infrastructure at the user level, as is the case on the Internet today. In this work we are concerned with the scenario where two parties establish a private shared session key, but only one party authenticates to the other; in fact, the unauthenticated party may wish to have strong anonymity guarantees. We present a desirable set of security, authentication, and anonymity goals for this setting and develop a model which captures these properties. Our approach allows for clients to choose among different levels of authentication. We also describe an attack on a previous protocol of Øverlier and Syverson, and present a new, efficient key exchange protocol that provides one-way authentication and anonymity.