Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2009. / Full text also available. Scroll down for electronic link.

Zugl.: Köln, Univ., Diss., 2009

Thesis (M.S.)--University of Missouri-Columbia, 2004. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 30, 2006) Vita. Includes bibliographical references.

Thesis (M.S. in computer engineering)--Washington State University, August 2006. / Includes bibliographical references (p. 83-84).

Traditional networks are no longer sustainable, lacks in scalability and when more devices connect to it the process of troubleshooting becomes laborious and time-consuming. In order to reduce the complexity of traditional networks, Cisco developed the concept Software-defined access (SD-Access) which combines a number of features and protocols to create an automated solution to make it easier for network technicians. This thesis investigates the SD-Access concept and compares it to today's traditional networks to find which solution is least demanding when it comes to identifying and adjusting a network problem. We use an example scenario which compares the process of performing troubleshooting in today's traditional networks versus the futures SDA networks. Based on our example scenario, it is shown that troubleshooting in traditional networks is a labor-intensive process. The troubleshooting will be arduous because the majority of the work has to occur manually. SD-Access reduces the workload by dynamically locating the node that causes the problem and provides suggestions to solve the problem. Our comparison between the two solutions contributes to an increased understanding of how the troubleshooting process can be enhanced with SD-Access and in which scenario one of them is preferable to the other. / Traditionella nätverk är inte längre hållbara, nätverken brister i skalbarhet och när allt fler enheter är uppkopplade mot nätverket blir felsökningsprocessen arbetsam och tidskrävande. För att frångå den komplexitet traditionella nätverk medför utvecklade Cisco konceptet Software-defined access. SD-Access kombinerar flertalet funktioner och protokoll för att skapa en automatiserad lösning som underlättar för nätverkstekniker. Syftet med detta examensarbete är att jämföra felsökningsprocessen i traditionella nätverk och SD-Access, målet är att ta fram vilken lösning som är minst krävande när det kommer till att identifiera och åtgärda ett problem. Genom att utforma ett exempelscenario och jämföra processen för hur felsökningen genomförs, kan likheter och skillnader mellan de olika implementationsalternativen sammanställas. Utifrån exempelscenariot framgår det att felsökning i traditionella nätverk är en arbetsam uppgift. Felsökningen blir mödosam eftersom merparten av arbetet som krävs för att identifiera och åtgärda felet sker manuellt. SD-Access minskar arbetsbördan genom att dynamiskt lokalisera noden som orsakar problemet och tillhandahåller förslag som kan lösa problemet. Jämförelsen mellan de två lösningarna bidrar till en ökad förståelse kring hur felsökningsprocessen kan effektiveras med SD-Access och i vilka scenarion ena implementationsalternativet är att föredra över det andra.

Creating a Tobacco Free Generation: a Tobacco Control Strategy for Scotland sets out the Scottish Government’s ambition to create a tobacco free generation of Scots by 2034. Smoking initiation occurs primarily in adolescence, and the national preventive strategy is correspondingly structured around a range of measures to reduce the availability, affordability and attractiveness of cigarettes and other tobacco products for children and young people. Primary among these are the increase in the minimum age of sale of tobacco from 16 to 18 years instituted in the UK in October 2007, and the ban on the display of tobacco and smoking related products in shops introduced in the Tobacco and Primary Medical Services Scotland Act 2010. This thesis explores young people’s smoking and cigarette access behaviours in the context of the increase in the age of sale of tobacco from 16 to 18 years in 2007, and their perceptions and representations of cigarette brand image in the context of the impending ban on point of sale displays and in anticipation of the introduction of generic cigarette packaging in the UK. A combination of individual, paired and triadic interviews were undertaken with a total of 60 13-15 year old young people recruited from youth clubs and other third sector organisations in two disadvantaged communities in Edinburgh. Around half the participants were regular smokers – defined as smoking a cigarette a day or more – with the remainder reporting ‘occasional’ or ‘experimental’ smoking, defined as intermittent smoking or having tried smoking on one or more occasions. Interviews focussed on participants’ usual cigarette sources, ability to access tobacco, participants’ favoured cigarette brands and their perspectives on recent legislative measures to reduce the attractiveness of cigarettes and other tobacco products for children and young people. Despite the increase in the minimum age of sale, most participants sourced cigarettes from shops, either directly or through intermediaries, and few reported any difficulties securing regular access to tobacco. Retail purchases were described in terms of a progression from more to less targeted purchasing strategies, with those experiencing difficulties buying cigarettes directly employing a range of strategies to identify and target retailers amenable to selling cigarettes to underage customers. Proxy purchases, i.e. purchases made through intermediaries, represented the predominating mode of acquisition among participants, and were described in terms of a progression from less to more targeted third party recruitment strategies, with older and more experienced regular smokers learning to identify and target particular types of individual for proxy purchases. Participants also had recourse to tobacco from a range of social and illicit sources, including ‘fag houses’, although these were not routinely accessed. The diverse cigarette sources identified by participants were not perceived to be equivalent, however, but were rather represented in terms of the parallel acquisition of a range of smoking related competencies. Participants’ diverse modes of tobacco acquisition, as such, reflected not merely their smoking status, with rates of retail cigarette purchasing increasing with age and regular smoking, but their status as a smoker through building symbolic capital. Participants foregrounded their smoking related knowledge and competencies to frame themselves as more or less ‘autonomous’ smokers. In discussions about participants favoured cigarette brands, participants would similarly foreground their knowledge of a range of perceived brand characteristics to frame themselves as more or less ‘discerning’ smokers. The importance of cigarette access and branding in shaping participants’ smoking identities has clear implications for smoking prevention policy, in terms of challenging the implied equivalence between the diverse cigarette sources available to young people routinely implied in the youth access literature and underscoring the importance of limiting the visual cues in cigarette packaging and point of sale advertising that facilitate the continued use of cigarettes as an ‘identity tool’.

The newly published Highway Safety Manual (HSM) has defined six different driveway types based on land use and parking lot size, including major commercial, minor commercial, major industrial/institutional, minor industrial/institutional, major residential, and minor residential. Major driveways are defined as having more than 50 parking spaces, while minor driveways are defined as those having less than 50 parking spaces. The HSM crash prediction models require the inputs of driveway type and density. However, the actual impacts of different types of driveways on the number of crashes are not clear. The crash modification factors were provided based on few past studies, with high standards of error. The purpose of this research is to develop a method to quantify the impact of driveway types and density on traffic crash frequencies, types, and severities. The different driveway types were collected in the State of Illinois and crashes occurring in the function area of each driveway were identified from the IDOT crash database (from 2005 to 2009). A cross section comparison was conducted to compare the mean crash frequency among different driveways. A further statistical analysis was used to develop a relationship between the density of each driveway type and crash frequency and rates.

In this dissertation, three multiuser detectors are developed for different application scenarios in direct-sequence code-division multiple access systems. The first detector is an overlapping widow decorrelating detector aimed at asynchronous reverse links. In companion with the design of this detector, a study on the decay property of the ideal decorrelating impulse response is presented, resulting in a quantitative description of the decay rate as a function of the Cholesky factors of the cross-correlation matrix of user signature signals. This result can serve as a guide for determining window length of decorrelating or minimum mean-squared error multiuser detection in asynchronous multiuser systems. Based on this result, a signal-adapted window-length determination algorithm is developed for the proposed detector. Several supporting utilities for efficient implementation of the proposed detector are also described. The second detector is a linear multiuser detector that is also aimed at the reverse links. Particularly, it is desirable for cases where the number of users is small and, thus, significant performance gain over the existing linear multiuser detectors is possible. Unlike in the decorrelating and MMSE detectors, minimizing the bit-error rate is taken as the optimization objective in the proposed detector. To avoid undesired local minima of the highly nonlinear BER cost function, a set of convex constraints is proposed for the optimization problem. It is shown that this constrained optimization problem has a unique solution once the decorrelating detector exists. It is also shown that the proposed detector achieves the best performance among linear detectors for most realistic situations. In addition, a Newton barrier method is developed for efficiently calculating the coefficient vector of the proposed detector (i.e., the solution of the constrained optimization problem). The third detector is an adaptive detector that is aimed at the forward link where information about interfering users is often unavailable. The proposed detector consists of a bank of blind adaptive filters, one for each resolvable path, followed by a channel estimator and a coherent diversity combiner. To allow blind adaptation, the impulse response of each filter is decomposed into two orthogonal parts: one part is fixed as the decorrelating coefficient vector for the path in the absence of interfering users and the other is free to be adapted according to the mean-squared error criterion. Assuming perfect adaptation, the performance of the proposed detector is shown to be between those of the decorrelating detector and the minimum mean-squared error detector. Other studies conducted include the effects of fading on the performance of the proposed detector and the behavior of the proposed blind adaptation algorithm. / Graduate

No description available.

This thesis presents a practical method of authentication utilizing multiple devices. The factors contributing to the practicality of the method are: the utilization of devices already commonly possessed by users and the amenability to being implemented on a wide variety of devices. The term “device” refers to anything able to perform cryptographic operations, store data, and communicate with another such device. In the method presented herein, multiple devices need to be associated with a single user to provide this user an identity in the system. A public key infrastructure is used to provide this identity. Each of the devices associated with a user possesses a public and private key which allow cryptographic operations to be performed. These operations include signing and encrypting data and will prove the identity of each device. The addition of these identities helps authenticate a single user. A wide variety of devices qualifies to be used by this authentication method. The minimum requirements are: the storage of data such as a private key, the ability to communicate, and a processor to perform the cryptographic operations. Smart devices possess these requirements and the manufacture of such devices can be realized at a reasonable cost. This method is malleable and implemented in numerous authentication protocols. This thesis illustrates and explains several instances of these protocols. The method’s primary novelty is its resistance to theft-based attacks, which results from the utilization of multiple devices to authenticate users. A user associated with multiple devices needs to be in possession of these devices to correctly perform the authentication task. This thesis focuses on the system design of this novel authentication method.