We provide a simple and improved security analysis of PMAC, a Parallelizable MAC (Message Authentication Code) defined over arbitrary messages. A similar kind of result was shown by Bellare, Pietrzak and Rogaway at Crypto 2005, where they have provided an improved bound for CBC (Cipher Block Chaining) MAC, which was introduced by Bellare, Killan and Rogaway at Crypto 1994. Our analysis idea is much more simpler to understand and is borrowed from the work by Nandi for proving Indistinguishability at Indocrypt 2005 and work by Bernstein. It shows that the advantage for any distinguishing attack for n-bit PMAC based on a random function is bounded by O(σq / 2^n), where σ is the total number of blocks in all q queries made by the attacker. In the original paper by Black and Rogaway at Eurocrypt 2002 where PMAC was introduced, the bound is O(σ^2 / 2^n). We also compute the collision probability of CBC MAC for suitably chosen messages. We show that the probability is Ω( lq^2 / N) where l is the number of message blocks, N is the size of the domain and q is the total number of queries. For random oracles the probability is O(q^2 / N). This improved collision probability will help us to have an efficient distinguishing attack and MAC-forgery attack. We also show that the collision probability for PMAC is Ω(q^2 / N) (strictly greater than the birthday bound). We have used a purely combinatorial approach to obtain this bound. Similar analysis can be made for other CBC MAC extensions like XCBC, TMAC and OMAC.

Evaluating options, making informed decisions, measuring performance, and achieving management objectives in forest fire management organizations (FFMO) requires the development and application of measures that reflect how an organization has managed challenges presented. This thesis makes use of historical fire records from 1961 – 2008 to assess the impact of weather and management interventions on fire suppression effectiveness and annual area burned (AAB) within Alberta’s Boreal Natural Region. Statistical models relating AAB to variations in the proportion of extreme fire behaviour potential days suggest a significant portion of inter-annual variation in AAB (82 %) can be explained by the proportion of days when the Build-Up Index exceeds its 95th percentile. Probability of containment and large fire occurrence models are also developed that provide the framework for a new approach to presuppression planning in Alberta that can account for factors significantly influencing fire occurrence and containment outcome.

Cloud computing provides business new working paradigm with the benefit of cost reduce and resource sharing. Tasks from different users may be performed on the same machine. Therefore, one primary security concern is whether user data is secure in cloud. On the other hand, hacker may facilitate cloud computing to launch larger range of attack, such as a request of port scan in cloud with virtual machines executing such malicious action. In addition, hacker may perform a sequence of attacks in order to compromise his target system in cloud, for example, evading an easy-to-exploit machine in a cloud and then using the previous compromised to attack the target. Such attack plan may be stealthy or inside the computing environment, so intrusion detection system or firewall has difficulty to identify it. The proposed detection system analyzes logs from cloud to extract the intensions of the actions recorded in logs. Stealthy reconnaissance actions are often neglected by administrator for the insignificant number of violations. Hidden Markov model is adopted to model the sequence of attack performed by hacker and such stealthy events in a long time frame will become significant in the state-aware model. The preliminary results show that the proposed system can identify such attack plans in the real network.

No description available.

The number of significant security incidents tends to increase day by day in recent years. The distributed denial of service attacks and worm attacks extensively influence the network and cause serious damages. In the thesis, we analyze these two critical distributed attacks. We propose an intrusion detection approach against this kind of attacks and implement an attack detection system based on the approach. We use anomaly detection of intrusion detecting techniques and observed the anomalous distribution of packet fields to perform the detection. The proposed approach records the characteristics of normal traffic volumes so that to make detections more flexible and more precise. Finally, we evaluated our approach by experiments.

Thesis (M.S.)--Naval Postgraduate School, 2003. / Title from title screen (viewed Aug. 3, 2004). "March 2003." Includes bibliographical references (p. 71-74). Also issued in paper format.

Thesis--School of Advanced Airpower Studies, Maxwell Air Force Base, Ala., 1992-93. / Title from title screen (viewed Nov. 3, 2003). "28 May 1993." Includes bibliographical references.

Rapid restoration of blood flow to ischemic myocardium is essential, however it causes further injury called reperfusion injury. Apoptosis contributes significantly to cardiomyocyte cell death during ischemia reperfusion injury, in which caspase family proteases play an essential role as they are the executioners of apoptosis. Caspase inhibitors showed promising cardioprotective results when administered before ischemia or at the start of reperfusion. However, before applying them in pre clinical studies of myocardial ischemia, several investigations needed to be taken to determine their therapeutic window post reperfusion, their effect on functional recovery of myocardium post ischemia, their mechanism of action. Methods Isolated perfused rat hearts were subjected to 35 min ischemia followed by 2 hr reperfusion where caspase inhibitors [broad spectrum caspase inhibitor (ZVAD, 0.1µM), specific caspase 3 inhibitor (DEVD, 0.07µM)] were added at the start of reperfusion, 15, 30 and 60 min after starting reperfusion at the presence or absence of Wortmannin (WORT, 100nM, PI3-kinase inhibitor). Hearts underwent triphenyl tetrazolium staining for infarct size assessment, or were frozen for Western blot analysis. Freshly isolated adult rat ventricular myocytes were subjected to 6 hr hypoxia followed by either 18 hr, where caspase inhibitors (ZVAD, 25µM and DEVD, 25µM) were added at the start of reoxygenation, 15, 30 and 60 min after starting reoxygenation at the presence or absence of Wortmannin (WORT, 100nM). Cardiomyocytes were analysed for viability, apoptosis, necrosis and intracellular caspase-3 activity using flow cytometry analysis. Isolated adult rat ventricular papillary muscles were subjected to 35 min hypoxia followed by 100 min reperfusion where caspase inhibitors [ZVAD (0.1 µM, 2.5µM) and DEVD (2.5µM)] were added at the start of reperfusion throughout. Power output was measured using work loop technique.

Background/Objectives: Gaps in care due to the movement of patients between health settings and/or practitioners, known as transitions of care (TOC), may contribute to second stroke or TIA events. The elements that impact TOC in the stroke/TIA population have not been fully elucidated. The purpose of this study is to identify key elements of a Doctor of Nursing Practice-led TOC model that could be used to develop and evaluate a TOC program for the stroke/TIA population. Design: A descriptive study was performed to 1) identify elements that may affect transitions of care using a stroke database and post-discharge phone surveys and 2) based on information from Aim 1, propose a DNP-led TOC model specific to the stroke/TIA. Setting: An urban primary stroke center in the southwest United States. Participants: All patients in the GWTG®-stroke database from May 1 - December 31st, 2012 and patients who consented at discharge from the stroke unit following a stroke or TIA. Measurements: Patient demographics including: length of stay (LOS), age, race, ethnicity, comorbidities, insurance, discharge status, thirty-day readmission rate, and follow up survey. Results: Patient data (n=276) from GWTG®-stroke database was obtained. Average LOS was 7.81 +/- 11.15 days. The majority of patients were greater than age 65 (59%); 53% relied on Medicare support; those age 50-59 (21%) were most likely to be uninsured (47%). Fifty-one percent were discharged directly home, 48% of those were referred to outpatient rehab services. Two-thirds received rehabilitation services during hospitalization. Eight patients experienced a subsequent hospital readmission; two of those had a repeat stroke event. Although patients reported understanding their discharge instructions, their perception of ongoing care was poor. Conclusion: Key elements of a TOC model specific to the stroke and TIA patient population could include: patient surveillance, comprehensive care planning, follow-up, stroke education and point of contact. Advanced practice nurses have been successful in leading such programs, and a DNP-led model providing continuity of care would support the transition of an effective model into clinical practice.

Partial replacement of cement by metakaolin is known to improve concrete durability, by refining the pore structure to improve fluid transport properties and by reducing the alkalinity of the pore solution to make ASR less problematic. A gap exists in the literature as to the salt scaling performance and magnesium sulphate performance of metakaolin concrete. 10 concrete mixes were cast at w/cm ratios of 0.4 and 0.5. In addition to metakaolin, grade 80 slag was used as well as CSA GU cement. All replacement levels were tested for setting properties, compressive strength, drying shrinkage, sulphate resistance, salt scaling, ASR mitigation and chloride diffusion characteristics according to the appropriate CSA and ASTM standards. It was found that metakaolin showed better performance in magnesium sulphate solutions than slag and that metakaolin concretes attained strength and other durability properties much faster than mixes without it. Keywords: metakaolin, ASR, sulphate, magnesium, scaling, setting, diffusion