Volume Holographic Data Storage Systems (HDSS) has been of interest for almost seven decades, and are now considered as a viable option for Write Once Read Many (WORM) cold data storage applications. Thanks to the Bragg selectivity of thick volume holograms, HDSS stores several hundreds of holograms on top of each other, called multiplexed data pages, by which data recording density can be substantially increased compared to surface recordings. On the other hand, signal intensity upon reconstruction of such multiplexed data pages inversely scales with number of multiplexing squared. Therefore, longer detection time and/or a high power laser along with a large dynamic range material is needed to make HDSS a truly viable "fast and high density" option for WORM applications. Historically, the trade-off between data density and data rate is well recognized. The challenge has been partially solved by continuous efforts such as improvement of materials, optical architectures, opto-mechanical systems and signal processing [1,2]. In this dissertation, we provide an additional pathway for HDSS to further increase both data density and transfer rates which is Cavities Enhancement Techniques for HDSS, to overcome the fundamental tradeoff. Key ideas are: recycling light with cavity to enhance data rate, and increasing number of multiplexing by combining cavity-eigenmode multiplexing, a subset of orthogonal phasecode multiplexing, with angular multiplexing. Based on this idea, we design and demonstrate Cavity-enhanced HDSS in such a way that we increase data rate and/or data density by at least factor of 2 while taking advantage of previous improvements as they are, or only with the minimum amount of modifications. In Section 1, we review history of HDSS and summarize the latest research results of HDSS and requirements on modern optical data storage systems as they relate to our solutions. In Section 2, theory of volume holography is reviewed by emphasizing understanding of angular and orthogonal phase code multiplexing. In Section 3 the theory of cavity enhanced reference arms is presented. We discuss how cavities provide a coherent boost to the beam power, which can be used in recording to alleviate source power requirements and/or increase the data recording rate and demonstrate the enhancement experimentally. Beyond basic enhancement, cavities also enable orthogonal phase code multiplexing via cavity eigenmodes. In Section 4, we experimentally demonstrate angular and orthogonal phase code hybrid multiplexing to overcome the limitation of the maximum number of multiplexing imposed by the geometrical constraints of angular multiplexing. In Section 5, novel aspects of the research are discussed in conjunction with the application of the technology for commercial use. Conclusions and future research direction are addressed in Section 6.

This study investigated the effects of selected spelling teaching methods on spelling mastery of upper-elementary, learning disabled students. It also examined the value of assessing learning disabled students' modality preferences for diagnostic/prescriptive purposes.The study's significance is that it sought to (a) determine whether students classified as learning disabled can identify their preferred learning modes; (b) determine whether matching modes of instruction to students' modality reference(s) results in greater achievement; and (c) identify a systematic way of prescribing instruction for learning disabled students.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

The understanding of cellular metabolism has been an intriguing challenge in classical cellular biology for decades. Essentially, cellular metabolism can be viewed as a complex system of enzyme-catalysed biochemical reactions that produces the energy and material necessary for the maintenance of life. In modern biochemistry, it is well-known that these reactions group into metabolic pathways so as to accomplish a particular function in the cell. The identification of these metabolic pathways is a key step to fully understanding the metabolic capabilities of a given organism. Typically, metabolic pathways have been elucidated via experimentation on different organisms. However, experimental findings are generally limited and fail to provide a complete description of all pathways. For this reason it is important to have mathematical models that allow us to identify and analyze metabolic pathways in a computational fashion. This is precisely the main theme of this thesis. We firstly describe, review and discuss existent mathematical/computational approaches to metabolic pathways, namely stoichiometric and path finding approaches. Then, we present our initial mathematical model named the Beasley-Planes (BP) model, which significantly improves on previous stoichiometric approaches. We also illustrate a successful application of the BP model to optimally disrupt metabolic pathways. The main drawback of the BP model is that it needs as input extra pathway knowledge. This is especially inappropriate if we wish to detect unknown metabolic pathways. As opposed to the BP model and stoichoimetric approaches, this issue is not found in path finding approaches. For this reason a novel path finding approach is built and examined in detail. This analysis serves us as inspiration to build the Improved Beasley-Planes (IBP) model. The IBP model incorporates elements of both stoichometric and path finding approaches. Though somewhat less accurate than the BP model, the IBP model solves the issue of extra pathway knowledge. Our research clearly demonstrates that there is a significant chance of developing a mathematical optimisation model that underlies many/all metabolic pathways.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

This study evaluated 227 students attending 12 classes of the Apprentice Medical Services Specialist Resident Course. Six classes containing a total of 109 students took the Block One Tests in the traditional paper and pencil form. Another six classes containing a total of 118 students took the same Block One Tests on computers. A confidence level of .99 and level of signifi­cance of .01 was established. An independent samples t-test was conducted on the sample. Additionally, a one-way analysis of variance was performed between the classes administered the Block One Tests on computers. Several other frequencies and comparisons of Block One Test scores and other variables were accomplished. The variables examined included test versions, shifts, student age, student source, and education levels. The study found no significant difference between test administration modes. This study concluded that computer-administering tests identical to those typically administered in the traditional paper and pencil manner had no significant effect on achievement. It is important to note, however, that the conclusion may only be valid if the computer-administered test contains exactly the same test items, in the same order and format, with the same layout, structure, and choices as the traditional paper and pencil test. In other words, unless the tests are identical in every possible way except the actual test administration mode this conclusion may not be applicable.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

The aim of this Master's thesis is to define the particular modes of public tenders in the Czech republic. The awarding of the public tenders represents special mean of concluding the public contracts governed by the Act N. 137/2006 Coll. This thesis concentrates mainly on the description of the particular methods of awarding the public tenders, the conditions required for their use as well as on the procurement procedure itself. The awarding procedure is characterized in accordance with the European judicial decisions, Czech case law and also the decisions of the Office for Protection of Competition. In relation to the newly adopted European directives the thesis analyses also the changes that are brought by these directives to the subject matter.