Using mobile agents to detect and recover from node compromise in path-based DoS attacks in wireless sensor networks

Wireless sensor networks represent a new generation of real-time embedded systems with significantly different communication constraints from the traditional networked systems. With their development, a new attack called a path-based DoS (PDoS) attack has appeared. In a PDoS attack, an adversary, either inside or outside the network, overwhelms sensor nodes by flooding a multi-hop end-to end communication path with either replayed packets or injected spurious packets. Detection and recovery from PDoS attacks have not been given much attention in the literature. In this article, we propose a solution using mobile agents which can detect PDoS attacks easily and efficiently and recover the compromised nodes.

Decision analysis of statistically detecting distributed denial-of-service flooding attacks

There are two statistical decision making questions regarding statistically detecting sings of denial-of-service flooding attacks. One is how to represent the distributions of detection probability, false alarm probability and miss probability. The other is how to quantitatively express a decision region within which one may make a decision that has high detection probability, low false alarm probability and low miss probability. This paper gives the answers to the above questions. In addition, a case study is demonstrated.

Algebraic attacks on clock-controlled stream ciphers

We present an algebraic attack approach to a family of irregularly clock-controlled bit-based linear feedback shift register systems. In the general set-up, we assume that the output bit of one shift register controls the clocking of other registers in the system and produces a family of equations relating the output bits to the internal state bits. We then apply this general theory to four specific stream ciphers: the (strengthened) stop-and-go generator, the alternating step generator, the self-decimated generator and the step1/step2 generator. In the case of the strengthened stop-and-go generator and of the self-decimated generator, we obtain the initial state of the registers in a significantly faster time than any other known attack. In the other two situations, we do better than or as well as all attacks but the correlation attack. In all cases, we demonstrate that the degree of a functional relationship between the registers can be bounded by two. Finally, we determine the effective key length of all four systems.

Algebraic attacks on clock-controlled cascade ciphers

In this paper, we mount the first algebraic attacks against clock controlled cascade stream ciphers. We first show how to obtain relations between the internal state bits and the output bits of the Gollmann clock controlled cascade stream ciphers. We demonstrate that the initial states of the last two shift registers can be determined by the initial states of the others. An alternative attack on the Gollmann cascade is also described, which requires solving quadratic equations. We then present an algebraic analysis of Pomaranch, one of the phase two proposals to eSTREAM. A system of equations of maximum degree four that describes the full cipher is derived. We also present weaknesses in the filter functions of Pomaranch by successfully computing annihilators and low degree multiples of the functions.

Cost-effectiveness of psychological and pharmacological interventions for generalized anxiety disorder and panic disorder

Objective: To assess from a health sector perspective the incremental cost-effectiveness of interventions for generalized anxiety disorder (cognitive behavioural therapy [CBT] and serotonin and noradrenaline reuptake inhibitors [SNRIs]) and panic disorder (CBT, selective serotonin reuptake inhibitors [SSRIs] and tricyclic antidepressants [TCAs]).

Method: The health benefit is measured as a reduction in disability-adjusted life years (DALYs), based on effect size calculations from meta-analyses of randomised controlled trials. An assessment on second stage filters ('equity', 'strength of evidence', 'feasibility' and 'acceptability to stakeholders') is also undertaken to incorporate additional factors that impact on resource allocation decisions. Costs and benefits are calculated for a period of one year for the eligible population (prevalent cases of generalized anxiety disorder/panic disorder identified in the National Survey of Mental Health and Wellbeing, extrapolated to the Australian population in the year 2000 for those aged 18 years and older). Simulation modelling techniques are used to present 95% uncertainty intervals (UI) around the incremental cost-effectiveness ratios (ICERs).

Results: Compared to current practice, CBT by a psychologist on a public salary is the most cost-effective intervention for both generalized anxiety disorder (A$6900/DALY saved; 95% UI A$4000 to A$12 000) and panic disorder (A$6800/DALY saved; 95% UI A$2900 to A$15 000). Cognitive behavioural therapy results in a greater total health benefit than the drug interventions for both anxiety disorders, although equity and feasibility concerns for CBT interventions are also greater.

Conclusions: Cognitive behavioural therapy is the most effective and cost-effective intervention for generalized anxiety disorder and panic disorder. However, its implementation would require policy change to enable more widespread access to a sufficient number of trained therapists for the treatment of anxiety disorders.

High stakes principalship - sleepless nights, heart attacks and sudden death accountabilities: reading media representations of the US principal shortage

The possible shortage of applicants for principal positions is news in both Australia and abroad. We subject a corpus of predominantly US news article to deconstructive narrative analysis and find that the dominant media representation of principals' work is one of long hours, low salary, high stress and sudden death from high stakes accountabilities. However reported US policy interventions focus predominantly on professional development for aspirants. We note that this will be insufficient to reverse the lack of applications, and suggest that the dominant media picture of completely unattractive principals' work, meant to leverage a policy solution will perhaps paradoxically perpetuate the problem. This picture is also curiously at odds with research that reports high job satisfaction among principals. We suggest that there is a dominant binary of victim and saviour principal in both media and policy which prevents some strategic re-thinking about how the principalship might be different.

Mutually clock-controlled feedback shift registers provide resistance to algebraic attacks

Algebraic attacks have been applied to several types of clock-controlled stream ciphers. However, to date there are no such attacks in the literature on mutually clock-controlled ciphers. In this paper, we present a preliminary step in this direction by giving the first algebraic analysis of mutually clock-controlled feedback shift register stream ciphers: the bilateral stop-and-go generator, A5/1, Alpha 1 and the MICKEY cipher. We show that, if there are no regularly clocked shift registers included in the system, mutually clock-controlled feedback shift register ciphers appear to be highly resistant to algebraic attacks. As a demonstration of the weakness inherent in the presence of a regularly clocked shift register, we present a simple algebraic attack on Alpha 1 based on only 29 keystream bits.

Information theory based detection against network behavior mimicking DDoS attacks

DDoS is a spy-on-spy game between attackers and detectors. Attackers are mimicking network traffic patterns to disable the detection algorithms which are based on these features. It is an open problem of discriminating the mimicking DDoS attacks from massive legitimate network accessing. We observed that the zombies use controlled function(s) to pump attack packages to the victim, therefore, the attack flows to the victim are always share some properties, e.g. packages distribution behaviors, which are not possessed by legitimate flows in a short time period. Based on this observation, once there appear suspicious flows to a server, we start to calculate the distance of the package distribution behavior among the suspicious flows. If the distance is less than a given threshold, then it is a DDoS attack, otherwise, it is a legitimate accessing. Our analysis and the preliminary experiments indicate that the proposed method- can discriminate mimicking flooding attacks from legitimate accessing efficiently and effectively.

Moral panic : the old and the new

The theory of moral panics has been prominent in the sociology of deviance since the 1970s. This article uses this theory to trace the rise of the moral panic around the high number of heroin overdose deaths in Australian in the mid to late 1990s. It argues, however, that much of the panic was generated by groups not traditionally associated with moral panics, but by political progressives in the field of illicit drugs as well as victims, parent groups, and those who work with illicit drug users. In this way it was not a conventional right-wing moral crusade, but it was no less a moral panic.

Source-based filtering scheme against DDOS attacks

IP address spoofing is employed by a lot of DDoS attack tools. Most of the current research on DDoS attack packet filtering depends on cooperation among routers, which is hard to achieve in real campaigns. Therefore, in the paper, we propose a novel filtering scheme based on source information in this paper to defend against various source IP address spoofing. The proposed method works independently at the potential victim side, and accumulates the source information of its clients, for instance, source IP addresses, hops from the server during attacks free period. When a DDoS attack alarm is raised, we can filter out the attack packets based on the accumulated knowledge of the legitimate clients. We divide the source IP addresses into n(1 ≤ n ≤ 32) segments in our proposed algorithm; as a result, we can therefore release the challenge storage and speed up the procedure of information retrieval. The system which is proposed by us and the experiments indicated that the proposed method works effectively and efficiently.

Human sympathetic nerve biology : parallel influences of stress and epigenetics in essential hypertension and panic disorder

Patients with panic disorder provide a clinical model of stress. On a "good day," free from a panic attack, they show persistent stress-related changes in sympathetic nerve biology, including abnormal sympathetic nerve single-fiber firing ("salvos" of multiple firing within a cardiac cycle) and release of epinephrine as a cotransmitter. The coreleased epinephrine perhaps originates from in situ synthesis by phenylethanolamine N-methyltransferase (PNMT). In searching for biological evidence that essential hypertension is caused by mental stress—a disputed proposition—we note parallels with panic disorder, which provides an explicit clinical model of stress: (1) There is clinical comorbidity; panic disorder prevalence is increased threefold in essential hypertension. (2) For both, epinephrine cotransmission is present in sympathetic nerves. (3) In panic disorder and essential hypertension, but not in health, single-fiber sympathetic nerve firing salvos occur. (4) Tissue nerve growth factor is increased in both conditions (nerve growth factor is a stress reactant). (5) There is induction of PNMT in sympathetic nerves. Essential hypertension exhibits a further manifestation of mental stress: there is activation of noradrenergic brain stem neurons projecting to the hypothalamus and amygdala. These pathophysiological findings strongly support the view that chronic mental stress is important in the pathogenesis of essential hypertension. A hypothesis now under test is whether in both disorders, under prevailing conditions of ongoing stress, PNMT induced in sympathetic nerves acts as a DNA methylase, causing the norepinephrine transporter (NET) gene silencing that is present in both conditions. PNMT can have an intranuclear distribution, binding to DNA. We have demonstrated that the reduced neuronal noradrenaline reuptake present in both disorders does have an epigenetic mechanism, with demonstrable reduction in the abundance of the transporter protein, the NET gene silencing being associated with DNA binding by the methylation-related inhibitory transcription factor MeCP2.

A controlled trial of internet-based cognitive-behavioural therapy for panic disorder with face-to-face support from a general practitioner or email support from a psychologist

Background: Panic disorder (PD) is one of the most common anxiety disorders seen in general practice, but provision of evidence-based cognitive-behavioural treatment (CBT) is rare. Many Australian GPs are now trained to deliver focused psychological strategies, but in practice this is time consuming and costly.

Objective: To evaluate the efficacy of an internet-based CBT intervention (Panic Online) for the treatment of PD supported by general practitioner (GP)-delivered therapeutic assistance.

Design: Panic Online supported by GP-delivered face-to-face therapy was compared to Panic Online supported by psychologist-delivered email therapy.

Methods: Sixty-five people with a primary diagnosis of PD (78% of whom also had agoraphobia) completed 12 weeks of therapy using Panic Online and therapeutic assistance with his/her GP (n = 34) or a clinical psychologist (n = 31). The mean duration of PD for participants allocated to these groups was 59 months and 58 months, respectively. Participants completed a clinical diagnostic interview delivered by a psychologist via telephone and questionnaires to assess panic-related symptoms, before and after treatment.

Results: The total attrition rate was 20%, with no group differences in attrition frequency. Both treatments led to significant improvements in panic attack frequency, depression, anxiety, stress, anxiety sensitivity and quality of life. There were no statistically significant differences in the two treatments on any of these measures, or in the frequency of participants with clinically significant PD at post assessment.

Conclusions: When provided with accessible online treatment protocols, GPs trained to deliver focused psychological strategies can achieve patient outcomes comparable to efficacious treatments delivered by clinical psychologists. The findings of this research provide a model for how GPs may be assisted to provide evidence-based mental healthcare successfully.

Therapist-assisted, internet-based treatment for panic disorder: can general practitioners achieve comparable patient outcomes to psychologists

Background: Mental illness is an escalating concern worldwide. The management of disorders such as anxiety and depression largely falls to family doctors or general practitioners (GPs). However, GPs are often too time constrained and may lack the necessary training to adequately manage the needs of such patients. Evidence-based Internet interventions represent a potentially valuable resource to reduce the burden of care and the cost of managing mental health disorders within primary care settings and, at the same time, improve patient outcomes.
Objective: The present study sought to extend the efficacy of a therapist-assisted Internet treatment program for panic disorder, Panic Online, by determining whether comparable outcomes could be achieved and maintained when Panic Online was supported by either GPs or psychologists.
Methods: Via a natural groups design, 96 people with a primary diagnosis of panic disorder (with or without agoraphobia) completed the Panic Online program over 12 weeks with the therapeutic assistance of their GP (n = 53), who had received specialist training in cognitive behavioral therapy, or a clinical psychologist (n = 43). Participants completed a clinical diagnostic telephone interview, conducted by a psychologist, and a set of online questionnaires to assess panic-related symptoms at three time periods (pretreatment, posttreatment, and 6 month follow-up).
Results: Both treatments led to clinically significant improvements on measures of panic and panic-related symptomatology from pretreatment to posttreatment. Both groups were shown to significantly improve over time. Improvements for both groups were maintained at follow-up; however, the groups did differ significantly on two quality of life domains: physical (F₁,₈₂ = 9.13, P = .00) and environmental (F₁,₈₂ = 4.41, P = .04). The attrition rate was significantly higher among those being treated by their GP (χ²₁ = 4.40, P = .02, N = 96).
Conclusions: This study provides evidence that Internet-based interventions are an effective adjunct to existing mental health care systems. Consequently, this may facilitate and enhance the delivery of evidence-based mental health treatments to increasingly large segments of the population via primary care systems and through suitably trained health professionals.