948 resultados para flash crowd attack


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Many terrorist attacks are accomplished by bringing explosive devices hidden in ordinary-looking objects to public places. In such case, it is almost impossible to distinguish a terrorist from ordinary people just from the isolated appearance. However, valuable clues might be discovered through analyzing a series of actions of the same person. Abnormal behaviors of object fetching, deposit, or exchange in public places might indicate potential attacks. Based on the widely equipped CCTV surveillance systems at the entrance of many public places, this paper proposes an algorithm to detect such abnormal behaviors for early warning of terrorist attack.

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The promise of cancer immunotherapy is that it will not only eradicate primary tumors but will generate systemic antitumor immunity capable of destroying distant metastases. A major problem that must first be surmounted relates to the immune resistance of large tumors. Here we reveal that immune resistance can be overcome by combining immunotherapy with a concerted attack on the tumor vasculature. The functionally related antitumor drugs 5,6-dimethylxanthenone-4-acetic acid (DMXAA) and flavone acetic acid (FAA), which cause tumor vasculature collapse and tumor necrosis, were used to attack the tumor vasculature, whereas the T-cell costimulator B7.1 (CD80), which costimulates T-cell proliferation via the CD28 pathway, was used to stimulate antitumor immunity. The injection of cDNA (60–180 µg) encoding B7.1 into large EL-4 tumors (0.8 cm in diameter) established in C57BL/6 mice, followed 24 h later by i.p. administration of either DMXAA (25 mg/kg) or FAA (300 mg/kg), resulted in complete tumor eradication within 2–6 weeks. In contrast, monotherapies were ineffective. Both vascular attack and B7.1 immunotherapy led to up-regulation of heat shock protein 70 on stressed and dying tumor cells, potentially augmenting immunotherapy. Remarkably, large tumors took on the appearance of a wound that rapidly ameliorated, leaving perfectly healed skin. Combined therapy was mediated by CD8+ T cells and natural killer cells, accompanied by heightened and prolonged antitumor cytolytic activity (P < 0.001), and by a marked increase in tumor cell apoptosis. Cured animals completely rejected a challenge of 1 x 107 parental EL-4 tumor cells but not a challenge of 1 x 104 Lewis lung carcinoma cells, demonstrating that antitumor immunity was tumor specific. Adoptive transfer of 2 x 108 splenocytes from treated mice into recipients bearing established (0.8 cm in diameter) tumors resulted in rapid and complete tumor rejection within 3 weeks. Although DMXAA and B7.1 monotherapies are complicated by a narrow range of effective doses, combined therapy was less dosage dependent. Thus, a broad range of amounts of B7.1 cDNA were effective in combination with 25 mg/kg DMXAA. In contrast, DMXAA, which has a very narrow range of high active doses, was effective at a low dose (18 mg/kg) when administered with a large amount (180 µg) of B7.1 cDNA. Importantly, combinational therapy generated heightened antitumor immunity, such that gene transfer of B7.1 into one tumor, followed by systemic DMXAA treatment, led to the complete rejection of multiple untreated tumor nodules established in the opposing flank. These findings have important implications for the future direction and utility of cancer immunotherapies aimed at harnessing patients’ immune responses to their own tumors.

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This paper uses the H1 tracking ideas in the missile guidance problem. The controller performs as a Precision guidance controller for small desired attack angles although theoretically the formulas are valid (when intercepting a maneuvering target in a precision guidance point of view) only for the case of head on collision. The controller essentially navigates the missile in a unique relative arc that is de ned by the missile and target location and the desired attack angle.

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This paper furthers the research of Rollo, Luther and Atkinson 1999, and Rollo, Honey, Atkinson and Luther 2003, regarding the way in which building shape appears to contribute to the collection of fire-brand debris subject to ember attack. The paper will present a range of 2D fluid-mapping and 3D wind tunnel studies (Melaragno 1982) which have been correlated with the transportation characteristics of an ember laden air-field (Cheney and Sullivan 1997). Working with a range of generic building types the paper also introduces simple spatial modelling techniques which are being developed to illustrate the relationship between ember capture and changes in wind speed and air pressure.

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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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Information is the glue in any organization. It is needed for policy, decision-making, control, and co-ordination. If an organisation's information systems are disrupted or destroyed, then damage to the whole inevitably follows. This paper uses a proven systemic, analytic framework the Viable System Model (VSM) - in a functionalist mode, to analyse the vulnerabilities of an organisation's information resources to this form of aggression. It examines the tactics available, and where they can be used to effectively attack an organisation.

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This text introduces the concepts of information warfare from a non-military, organizational perspective. It is designed to stimulate managers to develop policies, strategies, and tactics for the aggressive use and defence of their data and knowledge base. The book covers the full gambit of information warfare subjects from the direct attack on computer systems to the more subtle psychological technique of perception management. It provides the framework needed to build management strategies in this area. The topics covered include the basics of information warfare, corporate intelligence systems, the use of deception, security of systems, modes of attack, a methodology to develop defensive measures, plus specific issues associated with information warfare.

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Previous work, in the area of defense systems has focused on developing a firewall like structure, in order to protect applications from attacks. The major drawback for implementing security in general, is that it affects the performance of the application they are trying to protect. In fact, most developers avoid implementing security at all. With the coming of new multicore systems, we might at last be able to minimize the performance issues that security places on applications. In our bodyguard framework we propose a new kind of defense that acts alongside, not in front, of applications. This means that performance issues that effect system applications are kept to a minimum, but at the same time still provide high grade security. Our experimental results demonstrate that a ten to fifteen percent speedup in performance is possible, with the potential of greater speedup.

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Background: Recent evidence shows a substantial short-term risk of ischaemic stroke after transient ischaemic attack (TIA). Identification of patients with TIA with a high short-term risk of stroke is now possible through the use of the “ABCD Score”, which considers age, blood pressure, clinical features and duration of symptoms predictive of stroke.

Aim: To evaluate the ability of dichotomising the ABCD Score to predict stroke at 7 and 90 days in a population with TIA presenting to an emergency department.

Methods: A retrospective audit was conducted on all probable or definite TIAs presenting to the emergency department of a metropolitan hospital from July to December 2004. The ABCD Score was applied to 98 consecutive patients with TIA who were reviewed for subsequent strokes within 90 days. Patients obtaining an ABCD Score ≥5 were considered to be at high risk for stroke.

Results: Dichotomising the ABCD Score categorised 48 (49%) patients with TIA at high risk for stroke (ABCD Score ≥5). This high-risk group contained all four strokes that occurred within 7 days (sensitivity 100% (95% confidence interval (CI) 40% to 100%), specificity 53% (95% CI 43% to 63%), positive predictive value 8% (95% CI 3% to 21%) and negative predictive value 100% (95% CI 91% to 100%)), and six of seven occurring within 90 days (sensitivity 86% (95% CI 42% to 99%), specificity 54% (95% CI 43% to 64%), positive predictive value 12.5% (95% CI 5% to 26%) and negative predictive value 98% (95% CI 88% to 100%)). Removal of the “age” item from the ABCD Score halved the number of false-positive cases without changing its predictive value for stroke.

Conclusion: In this retrospective analysis, dichotomising the ABCD Score was overinclusive but highly predictive in identifying patients with TIA at a high short-term risk of stroke. Use of the ABCD Score in the emergency care of patients with TIA is simple, efficient and provides a unique opportunity to prevent stroke in this population of patients.

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The plant hormone, abscisic acid (ABA), has previously been shown to have an impact on the resistance or susceptibility of plants to pathogens. In this thesis, it was shown that ABA had a regulatory effect on an extensive array of plant defence responses in three different plant and pathogen interaction combinations as well as following the application of an abiotic elicitor. In unique studies using ABA deficient mutants of Arabidopsis, exogenous ABA addition or ABA biosynthesis inhibitor application and simulated drought stress, ABA was shown to have a profound effect on the outcome of interactions between plants and pathogens of differing lifestyles and from different kingdoms. The systems used included a model plant and an important agricultural species: Arabidopsis thaliana (Arabidopsis) and Peronospora parasitica (a biotrophic Oomycete pathogen), Arabidopsis and Pseudomonas syringae pathovar tomato (a biotrophic bacterial pathogen) and an unrelated plant species, soybean (Glycine max) and Phytophthora sojae (a hemibiotrophic Oomycete pathogen), Generally, a higher than basal endogenous ABA concentration within plant tissues at the time of avirulent pathogen inoculation, caused an interaction shift towards what phenotypically resembled susceptibility. Conversely, a lower than basal endogenous ABA concentration in plants inoculated with a virulent pathogen caused a shift towards resistance. An extensive suppressive effect of ABA on defence responses was revealed by a range of techniques that included histochemical, biochemical and molecular approaches. A universal effect of ABA on suppression or induction of the phenylpropanoid pathway via regulation of the key entry point gene, phenylalanine ammonia-lyase (PAL), when stimulated by biotic or abiotic elicitors was shown. ABA also influenced a wide variety of other defence-related components such as: the development of a hypersensitive response (HR), the accumulation of the reactive oxyden species, hydrogen peroxide and the cell wall strengthening compounds lignin and callose, accumulation of SA and the phytoalexin, glyceollin and the transcription of the SA-dependent pathogenesis- related gene (PR-1). The near genome-wide microarray gene expression analysis of an ABA induced susceptible interaction also revealed an yet unprecedented insight into the great diversity of defence responses that were influenced by ABA that included: disease resistance like proteins, antimicrobial proteins as well as phenylpropanoid and tryptophan pathway enzymes. Subtle differences were found in the number and type of defence responses that were regulated by ABA in each type of plant and pathogen interaction that was studied. This thesis has clearly identified in plant/pathogen interactions previously unknown and important roles for ABA in the regulation of many defence responses.