35 resultados para Countermeasures.

em Deakin Research Online - Australia


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IP spoofing is a technique used to gain unauthorized access to computers, whereby the intruder sends messages to a computer with an IP address indicating that the message is coming from a trusted host. It causes serious security problem in the cyber world, and is currently exploited widely in the information warfare. This paper at first introduces the IP spoofing attack through examples, technical issues and attacking types. Later its countermeasures are analysed in detail, which include authentication and encription, filtering and IP traceback. In particular, an IP traceback mechanism, Flexible Deterministic Packet Marking (FDPM) is presented. Since the IP spoofing problem can not be solved only by technology, but it also needs social regulation, the legal issues and economic impact are discussed in the later part.

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As the trust issue in wireless sensor networks is emerging as one important factor in security schemes, it is necessary to analyze how to resist attacks with a trust scheme. In this paper we categorize various types of attacks and countermeasures related to trust schemes in WSNs. Furthermore, we provide the development of trust mechanisms, give a short summarization of classical trust methodologies and emphasize the challenges of trust scheme in WSNs. An extensive literature survey is presented by summarizing state-of-the-art trust mechanisms in two categories: secure routing and secure data. Based on the analysis of attacks and the existing research, an open field and future direction with trust mechanisms in WSNs is provided.

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To evaluate the effect of short-duration, high-load resistive exercise, with and without whole body vibration on lumbar muscle size, intervertebral disk and spinal morphology changes, and low back pain (LBP) incidence during prolonged bed rest, 24 subjects underwent 60 days of head-down tilt bed rest and performed either resistive vibration exercise (n = 7), resistive exercise only (n = 8), or no exercise (n = 9; 2nd Berlin Bed-Rest Study). Discal and spinal shape was measured from sagittal plane magnetic resonance images. Cross-sectional areas (CSAs) of the multifidus, erector spinae, quadratus lumborum, and psoas were measured on para-axial magnetic resonance images. LBP incidence was assessed with questionnaires at regular intervals. The countermeasures reduced CSA loss in the multifidus, lumbar erector spinae and quadratus lumborum muscles, with greater increases in psoas muscle CSA seen in the countermeasure groups (P ≤ 0.004). There was little statistical evidence for an additional effect of whole body vibration above resistive exercise alone on these muscle changes. Exercise subjects reported LBP more frequently in the first week of bed rest, but this was only significant in resistive exercise only (P = 0.011 vs. control, resistive vibration exercise vs. control: P = 0.56). No effect of the countermeasures on changes in spinal morphology was seen (P ≥ 0.22). The results suggest that high-load resistive exercise, with or without whole body vibration, performed 3 days/wk can reduce lumbar muscle atrophy, but further countermeasure optimization is required.

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Physical inactivity is a potent stimulus for vascular remodeling, leading to a marked decrease in conduit artery diameter. However, little is known about the impact of physical inactivity on artery wall thickness or wall:lumen ratio or the potential of exercise countermeasures to modify artery wall thickness. The purpose of the study was to examine the impact of 60 days of bed rest, with or without exercise countermeasures, on carotid and superficial femoral artery wall thickness. Eighteen men were assigned to bed rest (second Berlin Bed Rest Study) and randomly allocated to control, resistive exercise, or resistive vibration exercise. Both exercise countermeasures were applied 3 times per week while the subjects were in the supine position on the bed. Sonography was used to examine baseline diameter and wall thickness of the carotid and femoral arteries. Bed rest decreased diameter of the superficial femoral artery (P=0.001) but not the carotid artery (P=0.29). Bed rest induced a significant increase in carotid and superficial femoral artery wall thickness (P=0.007 and 0.03) and wall:lumen ratio (P=0.009 and 0.001). Exercise prevented the increase in wall thickness of the carotid artery. In addition, exercise partly prevented the increased wall:lumen ratio in the superficial femoral artery. In conclusion, 8 weeks of bed rest resulted in approximately 20% increase in conduit artery wall thickness. Exercise countermeasures completely (carotid artery) or partly (superficial femoral artery) abolished the increase in wall thickness. These findings suggest that conduit artery wall thickness, a vascular characteristic associated previously with atherosclerosis, can rapidly adapt to physical inactivity and exercise in humans.

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As part of the 2nd Berlin BedRest Study (BBR2-2), we investigated the pattern of muscle atrophy of the postero-lateral hip and hamstring musculature during prolonged inactivity and the effectiveness of two exercise countermeasures. Twenty-four male subjects underwent 60 days of head-down tilt bedrest and were assigned to an inactive control (CTR), resistive vibration exercise (RVE), or resistive exercise alone (RE) group. Magnetic resonance imaging (MRI) of the hip and thigh was taken before, during, and at end of bedrest. Volume of posterolateral hip and hamstring musculature was calculated, and the rate of muscle atrophy and the effect of countermeasure exercises were examined. After 60 days of bedrest, the CTR group showed differential rates of muscle volume loss (F = 21.44; P ≤ 0.0001) with fastest losses seen in the semi-membranosus, quadratus femoris and biceps femoris long head followed by the gluteal and remaining hamstring musculature. Whole body vibration did not appear to have an additional effect above resistive exercise in preserving muscle volume. RE and RVE prevented and/or reduced muscle atrophy of the gluteal, semi-membranosus, and biceps femoris long head muscles. Some muscle volumes in the countermeasure groups displayed faster recovery times than the CTR group. Differential atrophy occurred in the postero-lateral hip musculature following a prolonged period of unloading. Short-duration high-load resistive exercise during bedrest reduced muscle atrophy in the mono-articular hip extensors and selected hamstring muscles. Future countermeasure design should consider including isolated resistive hamstring curls to target this muscle group and reduce the potential for development of muscle imbalances.

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We examined the effect of high-load fly-wheel (targeting the lower-limb musculature and concurrent loading of the spine via shoulder restraints) and spinal movement countermeasures against lumbar spine muscle atrophy, disc and spinal morphology changes and trunk isokinetic torque loss during prolonged bed-rest. Twenty-four male subjects underwent 90 d head-down tilt bed-rest and performed either fly-wheel (FW) exercises every three days, spinal movement exercises in lying five times daily (SpMob), or no exercise (Ctrl). There was no significant impact of countermeasures on losses of isokinetic trunk flexion/extension (p≥0.65). Muscle volume change by day-89 of bed-rest in the psoas, iliacus, lumbar erector spinae, lumbar multifidus and quadratus lumborum, as measured via magnetic resonance imaging (MRI), was statistically similar in all three groups (p≥0.33). No significant effect on MRI-measures of lumbar intervertebral disc volume, spinal length and lordosis (p≥0.09) were seen either, but there was some impact (p≤0.048) on axial plane disc dimensions (greater reduction than in Ctrl) and disc height (greater increases than in Ctrl). MRI-data from subjects measured 13 and 90-days after bed-rest showed partial recovery of the spinal extensor musculature by day-13 after bed-rest with this process complete by day-90. Some changes in lumbar spine and disc morphology parameters were still persistent 90-days after bed-rest. The present results indicate that the countermeasures tested were not optimal to maintain integrity of the spine and trunk musculature during bed rest. © 2011 Elsevier Ltd.

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We examined the effects of bed-rest, recovery and exercise countermeasures on bone density and structure at the distal tibia and radius as measured via high-resolution peripheral computed tomography. 24 subjects underwent 60-days of head-down tilt bed-rest and performed either resistive vibration exercise (RVE; n = 7), resistive exercise only (RE; n = 8) or no exercise (n = 9; 2nd Berlin BedRest Study; BBR2-2). Measurements were performed regularly during and up to 2-years after 60d bed-rest. At the distal tibia marked reductions in cortical area, cortical thickness and bone density but increases in periosteal perimeter and trabecular area were seen (p all<0.001). Recovery of most parameters occurred within 180d after bed-rest. At the distal radius, persistent increases in cortical area, cortical thickness, cortical density and total density and decreases in trabecular area were seen (p all ≤ 0.005). A significant effect of RVE (p = 0.003), but not RE, was seen on cortical area at the distal tibia, with few effects of the countermeasures observed on the remaining parameters. The current study represents the first implementation of high-resolution peripheral computed tomography in bed-rest in male subjects and helps to understand the patterns of bone remodeling due to bed-rest and recovery.

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The use of participational approaches to system design has been debated for a number of years. Within this paper we describe a method that was used to effectively design information systems and implement computer security countermeasures within an health care environment and shown how it was used in a number of environments.

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Currently mobile spam has been a major menace to the development of wireless networks. In this paper, the mobile spam problem and its countermeasures are analysed. In particular, we propose a Support Vector Machine to filter mobile spam. This mobile spam filtering system can be deployed in current wireless networks and achieve good performance in protecting end users and operators from mobile spam. Legislation issues and challenges to defend mobile spam are also discussed in the latter part of this paper.

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IP source address spoofing exploits a fundamental weakness in the Internet Protocol. It is exploited in many types of network-based attacks such as session hijacking and Denial of Service (DoS). Ingress and egress filtering is aimed at preventing IP spoofing. Techniques such as History based filtering are being used during DoS attacks to filter out attack packets. Packet marking techniques are being used to trace IP packets to a point that is close as possible to their actual source. Present IP spoofing  countermeasures are hindered by compatibility issues between IPv4 and IPv6, implementation issues and their effectiveness under different types of attacks. We propose a topology based packet marking method that builds on the flexibility of packet marking as an IP trace back method while overcoming most of the shortcomings of present packet marking techniques.

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The use of participational approaches in system design have been debated for a number of years. Within this paper we describe a method that was used to effectively design information systems and implement information security countermeasures within a health care environment. The paper shows how it was used in a number of different environments.

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Introduction:
Injuries sustained by Australian Defence Force (ADF) personnel during non-combat military training and sports activity are associated with increasing costs due to work days lost, medical treatment, compensation, and early retirement. In 2001, the ADF commissioned a systematic review of the evidence-base for reducing injuries associated with physical activity, while at the same time improving physical activity participation rates to sustain a trained, fit and deployable workforce.

Method:
Literature from on-line library databases, relevant unclassified military reports, and material from previously published sport-specific injury countermeasure reviews were systematically and critically analysed to address the study aims.

Results:
Modification of intensity, frequency and duration of basic military training activities and improved equipment is likely to reduce injury occurrence. Sports injury countermeasures used for the civilian population have merit for the ADF physical activity program. Injury countermeasures should be designed to minimise any possible deterrent effect on the motivation to participate in regular physical activity. Increasing the participation of ADF personnel in physical activity in the presence of evidence-based injury prevention strategies has the potential to increase health, fitness and deployability with minimal impact on injury frequency.

Conclusion:
Recommendations arising from the review include injury intervention trials in basic military training and sports. These and other interventions should be supported by refinement to ADF injury surveillance systems. Research should focus on interventions with the greatest gain for fitness, deployability, and cost effectiveness.


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Social network data has been increasingly made publicly available and analyzed in a wide spectrum of application domains. The practice of publishing social network data has brought privacy concerns to the front. Serious concerns on privacy protection in social networks have been raised in recent years. Realization of the promise of social networks data requires addressing these concerns. This paper considers the privacy disclosure in social network data publishing. In this paper, we present a systematic analysis of the various risks to privacy in publishing of social network data. We identify various attacks that can be used to reveal private information from social network data. This information is useful for developing practical countermeasures against the privacy attacks.

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SQL injection vulnerabilities poses a severe threat to web applications as an SQL Injection Attack (SQLIA) could adopt new obfuscation techniques to evade and thwart countermeasures such as Intrusion Detection Systems (IDS). SQLIA gains access to the back-end database of vulnerable websites, allowing hackers to execute SQL commands in a web application resulting in financial fraud and website defacement. The lack of existing models in providing protections against SQL injection has motivated this paper to present a new and enhanced model against web database intrusions that use SQLIA techniques. In this paper, we propose a novel concept of negative tainting along with SQL keyword analysis for preventing SQLIA and described our that we implemented. We have tested our proposed model on all types of SQLIA techniques by generating SQL queries containing legitimate SQL commands and SQL Injection Attack. Evaluations have been performed using three different applications. The results show that our model protects against 100% of tested attacks before even reaching the database layer.

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Email worms propagate across networks by taking advantage of email relationships. Modeling the propagation of email worms can help predict their potential damages and develop countermeasures. We propose a novel analytical model on the propagation process of modern reinfection email worms. It relies on probabilistic analysis, and thus can provide a steady and reliable assessment on the propagation dynamics. Additionally, by introducing virtual users to represent the repetitious spreading process, the proposed model overcomes the computational challenge caused by reinfection processes. To demonstrate the benefits of our model, we conduct a series of experimental evaluation. The results show that our novel approach achieves a greater accuracy and is more suitable for modeling modern email worms than previous models.