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An analysis of the different spike attack arm swings used in elite levels of men's volleyballPlawinski, Marek Pawel 18 July 2008 (has links)
Objective
As part of this work, two preliminary studies were conducted that identified three possible swings used at the elite level of volleyball and the resulting ball velocities created using these swings. Therefore, the purpose of this work was to explore the kinematic aspects of the different spike attack arm swings (straight ahead (SA), cross body (CB) and outside (OS)) where each different swing was broken down into its constituent parts.
Methods
Six elite-level varsity players participated in this study. A motion tracking system was used to collect motion data which was used to calculate the kinematics of the upper arm during each of the swing types. A number of minimums and maximums were then calculated including maximum hand speed. To compare means between swings one-way ANOVA’s were used.
Results
Few differences were found between the swing types. The only difference seen between the SA CB swings was a more pronounced wrist flexion during the CB swing. It is possible that this helped propel the ball across the body during the CB. The OS swings differed from the CB and SA swings in that the OS was less horizontally adducted and there was a more pronounced external rotation during CB than during OS. These differences are likely to be responsible for the ball being hit away from the midline of the body during the OS swing. Typically, the hand speed results agreed with those of the study done previously concerning resulting ball speeds when these swings were employed.
Conclusions
Between the SA, CB and OS swing types, only the OS was consistantly different throughout the three studies. It is recommended that future studies attempt to examine the whole body during these types of swings. Also, it appears that elite-level players may be quite different kinematically, and each one should be treated as a separate case in a training situation. The findings of these studies may help coaches, trainers and athletes develop better training, injury prevention and rehabilitation programs in the sport. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2008-07-16 12:10:06.42
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Metakaolin Effects on Concrete DurabilityZeljkovic, J. Michael 18 February 2010 (has links)
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
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Attack on WiFi-based Location Services and SSL using Proxy ServersFeng, Jun Liang 02 January 2014 (has links)
Wireless LANs are very common in any household or business today. It allows access to their home or business network and the Internet without using wires. Their wireless nature allows mobility and convenience for the user and that opens up a lot of new possibilities in mobile devices such as smartphones and tablets. One application that makes use of wireless LANs is positioning, which can be used in areas where Global Positioning Systems may have trouble functioning or not at all. However, a drawback of using wireless communication is that it is susceptible to eavesdropping and jamming. Once the wireless signal is jammed, an attacker can set up fake access points on different channels or frequencies to impersonate a legitimate access point. In this thesis, this attack is performed specifically to trick WiFi-based location services. The attack is shown to work on Skyhook, Google, Apple and Microsoft location services, four of the major location service providers, and on dual-band hardware. Some countermeasures to such an attack are also presented.
The web is an important part of many people???s lives nowadays. People expect that their privacy and confidentiality is preserved when they use the web. Previously, web traffic uses HTTP which meant traffic is all unencrypted and can be intercepted and read by attackers. This is clearly a security problem so many websites now default to using a more secure protocol, namely HTTPS which uses HTTP with SSL, and forces the user to HTTPS if they connect to the no SSL protocol. SSL works by exchanging keys between the client and server and the actual data is protected using the key and the cipher suite that is negotiated between the two. However, if a network uses a proxy server, it works slightly different. The SSL connection is broken up into two separate ones and that creates the potential for man-in-the-middle attacks that allow an attacker to intercept the data being transmitted. This thesis analyzes several scenarios in which an adversary can conduct such a man-in-the-middle attack, and potential detection and mitigation methods.
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Evaluating the Effectiveness of Sybil Attacks Against Peer-to-Peer BotnetsVerigin, Adam Louis 18 December 2013 (has links)
Botnets are networks of computers which have been compromised by malicious software which enables a remotely located adversary to control them and focus their collective power on specific tasks. Botnets pose a significant global threat, with tangible political, economic and military ramifications and have resultingly become a field of significant interest within the cyber-security research community. While a number of effective defence techniques have been devised for botnets utilizing centralized command and control infrastructures, few of these techniques are suitable for defending against larger-scale peer-to-peer (P2P) botnets. In contrast, the sybil attack, combined with index poisoning is an established defence technique for P2P botnets. During a sybil attack, fake bots (\ie sybils) are inserted into the botnet. These sybils distribute fake commands to bots, causing them not to carry out illicit activities. Bots also then unwittingly redistribute the fake commands to other bots in the botnet.
This work uses packet-level simulation of a Kademlia-based P2P botnet to evaluate 1) the impact that the location of sybils within the underlying network topology can have on the effectiveness of sybil attacks and 2) several potential optimizations to the placement of sybils within the underlying network topology. / Graduate / 0537 / 0544 / 0984
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Correlation of Heterogenous IDS Alerts for Attack DetectionCarey, Nathan January 2004 (has links)
With the increasing use of Intrusion Detection Systems (IDS) as a core component of network security, a vast array of competing products have appeared to fulfil the role of reliably detecting potential breaches of security in a network. The domain of detecting intrusions is large. This leads to products which are better at detecting some intrusions than others, and so to the use of multiple different types of IDS within a network. This typical usage, combined with the common practice of using IDS at multiple points in the network, requires sophisticated management of heterogenous alerts from multiple sources. This management should enable correlation of alerts with the goal of better detecting attacks, and reducing the monitoring workload on administrators. This thesis presents an architecture utilising commodity components and the Intrusion Detection Message Exchange Format (IDMEF) to enable this type of alert management. A signature scheme for the specification of patterns of alerts that indicate multi-step attacks is given, and a methodology for analysing alerts using the architecture that was developed. The final outcomes are a signature system and collection of tools integrated in a GUI management interface to aid in the detection of attacks, and the results of utilising these tools on a series of experiments in attack detection.
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Aerodynamics of wrap-around fins in supersonic flowWilks, Brett Landon, Burkhalter, Johnny Evans, January 2005 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.
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Experiments in vortex formation of plunging & flapping flat platesStanley, Daniel C., January 2008 (has links)
Thesis (M.S. in Aerospace Engineering) -- University of Dayton. / Title from PDF t.p. (viewed 10/06/09). Advisor: Aaron Altman. Includes bibliographical references (p. 140-142).
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Enhancing Mobile Forensics on iOSJanuary 2015 (has links)
abstract: Due to the shortcomings of modern Mobile Device Management solutions, businesses
have begun to incorporate forensics to analyze their mobile devices and respond
to any incidents of malicious activity in order to protect their sensitive data. Current
forensic tools, however, can only look a static image of the device being examined,
making it difficult for a forensic analyst to produce conclusive results regarding the
integrity of any sensitive data on the device. This research thesis expands on the
use of forensics to secure data by implementing an agent on a mobile device that can
continually collect information regarding the state of the device. This information is
then sent to a separate server in the form of log files to be analyzed using a specialized
tool. The analysis tool is able to look at the data collected from the device over time
and perform specific calculations, according to the user's specifications, highlighting
any correlations or anomalies among the data which might be considered suspicious
to a forensic analyst. The contribution of this paper is both an in-depth explanation
on the implementation of an iOS application to be used to improve the mobile forensics
process as well as a proof-of-concept experiment showing how evidence collected
over time can be used to improve the accuracy of a forensic analysis. / Dissertation/Thesis / Masters Thesis Computer Science 2015
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Defending against inference attack in online social networksChen, Jiayi 19 July 2017 (has links)
The privacy issues in online social networks (OSNs) have been increasingly arousing the public awareness since it is possible for attackers to launch several kinds of attacks to obtain users' sensitive and private information by exploiting the massive data obtained from the networks. Even if users conceal their sensitive information, attackers can infer their secrets by studying the correlations between private and public information with background knowledge. To address these issues, the thesis focuses on the inference attack and its countermeasures.
First, we study how to launch the inference attack to profile OSN users via relationships and network characteristics. Due to both user privacy concerns and unformatted textual information, it is quite difficult to build a completely labeled social network directly. However, both social relations and network characteristics can help attribute inference to profile OSN users. We propose several attribute inference models based on these two factors and implement them with Naive Bayes, Decision Tree, and Logistic Regression. Also, to study network characteristics and evaluate the performance of our proposed models, we use a well-labeled Google employee social network extracted from Google+ for inferring the social roles of Google employees. The experiment results demonstrate that the proposed models are effective in social role inference with Dyadic Label Model performing the best.
Second, we model the general inference attack and formulate the privacy-preserving data sharing problem to defend against the attack. The optimization problem is to maximize the users' self-disclosure utility while preserving their privacy. We propose two privacy-preserving social network data sharing methods to counter the inference attack. One is the efficient privacy-preserving disclosure algorithm (EPPD) targeting the high utility, and the other is to convert the original problem into a multi-dimensional knapsack problem (d-KP) which can be solved with a low computational complexity. We use real-world social network datasets to evaluate the performance. From the results, the proposed methods achieve a better performance when compared with the existing ones.
Finally, we design a privacy protection authorization framework based on the OAuth 2.0 protocol. Many third-party services and applications have integrated the login services of popular social networking sites, such as Facebook and Google+, and acquired user information to enrich their services by requesting user's permission. However, due to the inference attack, it is still possible to infer users' secrets. Therefore, we embed our privacy-preserving data sharing algorithms in the implementation of OAuth 2.0 framework and propose RANPriv-OAuth2 to protect users' privacy from the inference attack. / Graduate
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The experience of non-epileptic attack disorder (NEAD) : a repertory grid study examining NEAD patients' construal of their disorderVaughan, Jennifer January 2011 (has links)
Non-epileptic attack disorder (NEAD) is a disorder resembling epilepsy, but is caused by psychological processes rather than neurological disturbance. Approximately 15-30% of patients referred to specialist epilepsy centres have NEAD as opposed to epilepsy. Research into NEAD has largely focused on the differential diagnosis of NEAD and identifying risk factors, such as abuse and psychopathology. Whilst this is important, there remains a paucity of research exploring the processes involved in the development and maintenance of NEAD, which contributes to the lack of research investigating treatment effectiveness and prognosis. Furthermore, there remains a paucity of research investigating patient perceptions and experiences, despite such factors influencing prognosis. Subsequently, the current study used repertory grid methodology to explore the largely overlooked domain of how individuals with NEAD construe their world (i.e. how they perceive themselves, others and their disorder). Twelve individuals with a diagnosis of NEAD were recruited from a clinical neuropsychology department within North-West England. This study was an exploratory, cross-sectional study using the repertory grid technique to explore the participants' construals of themselves and others, including construals of their ideal self and self before NEAD. Based on personal construct theory, this method aimed to overcome some of the methodological limitations inherent within NEAD research, by minimising researcher bias, exploring implicit and explicit perceptions and exploring both individual and group perceptions.A case series of grids was presented. Individual and multiple analyses were used to explore participants' construct systems. A data driven approach enabled hypotheses to be developed from the individual grids, which were explored via a composite grid and SocioNet analysis. Despite some themes being identified, the findings revealed the uniqueness of the participants' ways of construing, including a lack of shared understanding amongst the participants. The participants were unhappy with their current self and no longer construed themselves to be the person they were before the onset of NEAD. They also construed themselves as being distinct and/or alienated from others, although some participants construed positive consequences as a result of their NEAD. Whilst most participants agreed with their NEAD diagnosis 'label', they were less accepting of the psychological factors that characterise the diagnosis. Finally, physical health difficulties were construed as being preferable to experiencing mental health difficulties. The findings were discussed in relation to previous research and theoretical implications were highlighted. Clinical implications were highlighted, particularly how the current diagnostic and treatment system for individuals with NEAD may threaten their self-identity. Methodological considerations and recommendations for future research were also suggested. The repertory grid technique was found to be a useful and effective method to investigate the subjective perceptions of individuals with NEAD.
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