This paper presents the considerations that must be taken into account when formalizing a simulation model to determine the operational availability of a Navy training device. Consideration is given to those design and logistic support parameters that impact the general simulation model before it is formulated. These parameters, are then used as guidelines to collect and screen the data available for use in the general model. The general model is then translated into a computer simulation model. A specific training site is then chosen and data gathered to be used in the computer model. Design and logistic support parameters given consideration in this specific case were; component Mean-time-between-failures, repair capabilities (manual or automatic test equipment, and depot), spares provisioning, and repair or replacement times. The simulation model was then exercised by changing the provisioning on-site to determine its effect on the trainers operational availability. Of significant notice was the effects that provisioning had on manpower requirements in the area of maintenance.

<p>  </p> <p>Future artificial intelligence applications and data-intensive computations require the development of non-von Neumann architecture. Physical separation between a logic unit and a memory unit is one of the main bottlenecks of the traditional architecture, hindering unlocking the ultimate performance of electronic devices, such as power consumption and memory bandwidth limitation. However, to enable monolithic integration of high-performance logic and memory needs to resolve the fundamental thermal budget challenge of back-end-of-line (BEOL). In this regard, two-dimensional (2D) materials have drawn immense attention owing to their intrinsic performance, ultrathin bodies, and flexibility. The viability of low-temperature integration puts them in an advantageous position that rivals silicon technology.</p> <p><br></p> <p>Firstly, an entirely new phase change RRAM in MoTe2 can give rise to uniform switching by difference from a random filament formation of the conventional RRAM device. For a large memory array to function properly, it is crucial to have high nonlinearity of I-V characteristics for each device to suppress the sneak-path current. I experimentally demonstrate a proof-of-concept heterostructure consisting of 2D materials with the functionalities of the memory (MoTe2) and selector (WSe2). Next, a heterogeneously integrated 1-selector/1-resistor (1S1R) Ta2O5/MoTe2 RRAM cell was built for the first time employing 2D layered MoTe2 films, showing decent on/off-current ratios of ~730 and high nonlinearities of ∼5700. These values are considered state-of-the-art for built-in nonlinear RRAM devices to date. </p> <p><br></p> <p>Secondly, I demonstrate that a pure nitric oxide treatment at elevated temperatures provides a stable p-doping for monolayer WSe2. This approach allows achieving record high hole current densities of ~300 μA/μm and low contact resistances of ∼950 Ω·μm, while preserving the transistor on/off current ratio >2×106. This scalable pathway significantly improves the performance of p-type WSe2 transistors, opening new opportunities for p-type 2D materials to enable CMOS implementations for next-generation high-performance electronics. </p> <p><br></p> <p>Thirdly, I demonstrate all MoTe2 1-transistor/1-resistor (1T1R) memory cells, fabricated at low temperatures. The 1T1R cells can be switched with voltage ~ 1V, close to typical CMOS logic voltages. This demonstration underscores the potential of 2D materials and their monolithic integration toward the realization of future memory technologies. </p> <p><br></p> <p>Lastly, I adopt machine-learning (ML) algorithms to evaluate the design and process co-optimization from a vast number of 2D transistor device characteristics. This framework greatly optimizes the electrical performance of 2D transistors, serving as guidance for advancing future 2D electronics.</p>

No description available.

M.Ed. (Education) / Please refer to full text to view abstract

As the computer industry grows, so will the requirements for data storage. Magnetic memory has been the most stable method in terms of capacity and recording/reading speed. However, we have reached the point where a substantial increase in the capacity cannot be produced without increasing the size of the system. When compact discs (CDs) were introduced in the 1980�s they revolutionized the concept of data storage. While the initial force behind compact discs could easily be said to be the music industry, once recordable and rewritable discs became available they quickly found more use in the computer industry as backup devices. Since their inception, the capacity requirements have far exceeded what is available on a compact disc, and they are now following the same path as magnetic memories. Following this trend, it could be assumed that digital versatile discs or digital video discs (DVDs) have a limited lifetime as a storage medium. In fact it has been noted (Higuchi et al., 1999) that the maximum capacity of digital video discs will be reached in 3 � 5 years. The question then is, what comes next? The efficiency of conventional optical data storage is extremely poor. For an optically thick recording medium, both CDs and DVDs use less than 0.01% of the total volume to store the information. Three-dimensional bit optical data storage endeavors to increase the efficiency by recording information in a volume that is greater than 90% of the total volume. The concept of three-dimensional bit optical data storage was first proposed by Parthenopoulos and Rentzepis in 1989, where they demonstrated that capacities far exceeding that of compact discs could be achieved. Three-dimensional bit optical data storage relies on creating a highly localised chemical or physical change within a recording medium, such that further layers can be recorded without causing interference. Ideally the chemical/physical change in the material should be reversible to enable erasable/rewritable data storage. In order to create a highly localised effect nonlinear excitation can be used; whereby the excitation is limited to a small region around the focal spot. Depending on the material and recording method there are several techniques for reading the information such as transmission imaging or reflection confocal microscopy. However, all the recording and reading methods require focusing to a deep position within a recording medium, such focusing encounters spherical aberration as a result of the difference in the refractive indices between the immersion and recording media. This thesis has concentrated on several areas to understand and develop the concept of three-dimensional bit optical data storage. The photorefractive effect in crystals has been studied for many years and is now widely used in optoelectronic devices. The use of photorefractive polymers is a relatively new and exciting development in optical data storage. Until now they have been used solely in the area of holographic data storage. The research in this thesis was conducted using photorefractive materials that were fabricated in two polymer matrices, poly(N-vinylcarbazole) (PVK) and poly(Methyl Methacrylate) (PMMA). The recording samples also consisted of the following compounds in various proportions, 2,5-dimethyl-4-(p-nirtophenylazo)anisole (DMNPAA), 2,4,7-trinitro-9-fluorenone (TNF) and N-ethylcarbazole (ECZ). In this project two-photon excitation was used as the recording mechanism to achieve erasable/rewritable data storage in a photorefractive polymer. As a result of two-photon excitation, the quadratic dependence of excitation on the incident intensity produces an excitation volume that is confined to the focal region in both the transverse and axial directions. Therefore, focusing the laser beam above or below its previous position provides a method by which layers of information can be recorded in the depth direction of a material, without causing interference from neighbouring layers. The feasibility of two-photon excitation in photorefractive polymers is demonstrated in this thesis. The quadratic relationship between excitation and incident light in two-photon excitation requires high photon density to ensure efficient excitation. The use of ultra-short pulsed lasers, while effective, is not a practical solution for an optical data storage system. This thesis demonstrates the ability to produce three-dimensional erasable/rewritable data storage in a photorefractive polymer using continuous wave illumination. Using this technology it has been possible to achieve a density of 88 Gbits/cm3, which corresponds to a capacity of 670 Gbytes on a compact disc sized recording medium. This is an increase of 1000 times the capacity of a CD and 130 times the capacity of current DVDs. While erasable optical data storage is an exciting prospect there are problems associated with the deterioration of the information. For long term information storage a permanent recording process would be more practical. It is demonstrated that there is a point after which further increases in the recording power result in the formation of a micro-cavity. While two-photon excitation is the recording method for erasable data storage, the increase in power results in an increase in ultra-violet absorption such that multi-photon excitation may occur. This thesis demonstrates the ability to record multi-layered arrays of micro-cavities. The change in refractive index associated with an erasable bit is less than 1%. As a result only phase sensitive reading methods (transmission imaging or differential interference contrast (DIC) microscopy) can be used to image a recorded bit. Both transmission and DIC imaging systems have poor axial resolution and therefore limit the density of the recording system, as well as being large optical systems. The introduction of a split or quadrant detector reduces the size of the optical reading system and is demonstrated to be sensitive enough to detect the phase changes of a recorded bit. However, the change in refractive index across a micro-cavity is large enough that reflection confocal microscopy can be used to detect a bit. It is demonstrated in this thesis that multi-layered micro-cavity arrays can be read using reflection confocal microscopy. Focusing of light to deep positions within an optical thick recording medium has the effect of increasing spherical aberration resulting from the refractive index mismatching between the immersion and recording media. The work in this thesis illustrates the effect of spherical aberration on the performance of both the recording and reading systems. The work conducted in this thesis shows the ability to record multi-layered erasable/rewritable information in a photorefractive polymer using pulsed and continuous wave two-photon excitation. It has also been demonstrated that through multi-photon excitation multi-layered micro-cavity arrays can be fabricated. It has also been illustrated that while spherical aberration deteriorates the performance of the recording and reading systems it is possible to achieve a density of greater than 88 Gbits/cm3.

<p>The purpose of this thesis work was to make a survey of presently existing devices available in the market to store encryption keys; how the hacker intrudes into the device; what are the attacks behind</p><p>theft of the keys; how can we store encryption keys securely?</p><p>To achieve this purpose, an overview of the storage devices and attacks made by hackers was acquired through academic books and papers, Internet sites and magazines. Basic cryptography and related</p><p>algorithms were studied for the purpose of knowing how the encryption key is generated from these algorithms.</p><p>Under the category of storage devices, USBs (Universal Serial Bus), PDAs (Personal Digital Assistant) and Smart Cards were examined. Under the category of attacks on devices, attacks from hackers,</p><p>attacks from malicious code (Trojan Horses, viruses, worms), attacks from PDAs, attacks from Smart Cards, dictionary attacks and brute force attacks were studied.</p><p>Based on these requirements we have discussed and analyzed a proposed system to store the encryption keys securely to avoid these attacks.</p>

Graduation date: 1998

The aim of the thesis is to investigate how teaching devices, with focus on ICT use are regarded in education. I make comparison with teaching without technical devices, but emphasize the teaching with such devices. I address questions concerning what technical devices are used and in which way these devices may enhance the education process. In addition, in which way the devices influence power and communication. The methods indicate a deductive-abductive approach, observations, interviews, and questionnaires. The theoretical framework focuses, Linguistics, Pedagogy, cognition, and Informatics. The results-part is built up on two cases – one concerning teaching with technical devices, the other concerning teaching without those devices. The results imply that the schools of Sweden use computers and Internet in a very ‘common’ way. However, there are intentions to use cell phones with software to assist the teaching. By this approach, that would be possible to add an additional time to the lectures since the pupils and teachers can work outside the classroom. One problem with technical devices is named ‘noise’, which are things in between the ‘useful’ (technical) devices and issues around that can decrease the learning process. In addition; if the goal is to have a symmetrical relationship between teacher and pupil, it may be difficult without taking carefully account on the (technical) device in use, and perhaps regard them as cognitive tools. From what I found, the tools are not regarded as cognitive.

The purpose of this thesis work was to make a survey of presently existing devices available in the market to store encryption keys; how the hacker intrudes into the device; what are the attacks behind theft of the keys; how can we store encryption keys securely? To achieve this purpose, an overview of the storage devices and attacks made by hackers was acquired through academic books and papers, Internet sites and magazines. Basic cryptography and related algorithms were studied for the purpose of knowing how the encryption key is generated from these algorithms. Under the category of storage devices, USBs (Universal Serial Bus), PDAs (Personal Digital Assistant) and Smart Cards were examined. Under the category of attacks on devices, attacks from hackers, attacks from malicious code (Trojan Horses, viruses, worms), attacks from PDAs, attacks from Smart Cards, dictionary attacks and brute force attacks were studied. Based on these requirements we have discussed and analyzed a proposed system to store the encryption keys securely to avoid these attacks.

Quantum key-distribution (QKD) is a scheme for establishing shared secret key between remote parties. In such a scheme, quantum preparation and measurement devices (sources and detectors) are used. In existing theoretical treatments of QKD, the device models used do not capture all the imperfections which might occur in realistic devices. This creates a gap between the practical implementations and theoretical descriptions of QKD. In the present work, we contribute in bridging this gap by three methods: 1) Advancing the study of squashing models of measurement devices, 2) Devising an alternative to squashing models using statistical estimation in optical QKD, and 3) Modifying the security proof formalism of QKD to account for imperfect devices.