A computer program to simulate peak shapes from time-of-flight (TOF) mass spectrometers has been developed and significantly improved from a previous, unpublished version. This program can accurately simulate both TOF and orthogonal acceleration TOF mass analyser peak shapes, with contributions from initial ion properties, instrument geometry, and other factors including high voltage ripple and detector response. Grid effects have also been included, and simulations for two mass spectrometers are compared to actual recorded spectra. The dispersive effect on ion trajectories of parallel wires and grids has been computationally studied and a model derived for each case. The model is based on the effect wire geometry has on the intrinsic focussing effect of the grid. The models for parallel wires and rectangular grids have been coded into the simulation program described above, and the effect of grids on peak shapes in TOF mass spectrometers has been studied. Good correlation between simulated and actual peak shapes for rectangular grids was obtained for grids in different rotational orientations. A pulsed lens has been developed to reduce the velocity spread of ions in matrix assisted laser desorption/ionisation (MALDI) ion sources, with the aim to increase sensitivity in orthogonal acceleration TOF mass analysers. The system gave an increase in sensitivity of approximately five times over a range of masses, however instrument resolving power was reduced. A rotating sample stage was developed for MALDI mass spectrometers which offers the potential of high sample density, high positional accuracy and repeatability, and low seek times. The system involves reading the position of a disk mounted with MALDI sample spots and timing the laser pulse to coincide with spot availability at an aperture. The system was successfully used to perform mass calibration by using a calibrant sample located on a separate spot to the analyte. Mass resolved disk imaging was also performed over a disk radius using inks. The mass resolved image compared well to the optical image.

This research project investigates to what extent a social constructivist approach to teaching and learning online can enhance the use of language acquisition for learners of foreign languages. I designed an online role-play simulation in which the students sailed on the expedition of Nicolas Baudin to Australia and took different authentic roles on a simulated voyage. All communication was conducted in the French language, thus enabling the students to interact in realistic conversations, relevant to this historic event. Being in a third year TAFE French class, the students had already been exposed to sound grounding in grammar, relevant vocabulary, and use of colloquial and idiomatic expressions, and thus they had acquired a reasonably high level of proficiency in the language. The study was conducted over a four-week period in which I examined the intense interaction between the participants, while fulfilling the role of facilitator/moderator. In this role, I gave clear guidelines as to what was expected from the participants; provided the students with their identity which was unknown to the other participants during the simulation; created incidents through a weekly “Course of Events” announcement; answered all questions within 12 – 24 hours; encouraged engagement within the learning community; made occasional suggestions if the characters seemed uncertain of what to do next; and, above all, endeavoured to create a non-threatening, friendly online environment for the students. After the four-week online role-play simulation, the participants met for a debriefing session in which they revealed their identities and discussed any issues, in particular technical issues, that had emerged. This provided an opportunity for the participants to disengage from the virtual world in which they have been immersed for four weeks as well as an opportunity to reflect upon their personal learning. A qualitative methodology, drawing on interpretive research, was employed to analyse the data. Student pre- and post-questionnaires, online contributions by the students and the debriefing discussion were used as the major sources of data collection. Most of the students took up the challenge of interacting online through asynchronous and synchronous communication. The study focused on how the use of a social constructivist epistemology could enhance language acquisition for learners of foreign languages and also analysed to what extent did the students’ participation in a webbased online role-play simulation affect their communication skills and fluency in the second language. The findings provided me with guidance for future implementation of online role-play simulations in which I would ensure that all students have the basic computer skills and necessary access to internet in order to participate fully in the simulation. Nevertheless, this study demonstrated many benefits to the language enhancement of the participants and will become a regular activity as it permits students to use their conversational skills in a “real-life” virtual learning community.

<p>The number of automobiles has been increased on the road in the past few years. Due to high density of vehicles, the potential threats and road accident is increasing. Wireless technology is aiming to equip technology in vehicles to reduce these factors by sending messages to each other.</p><p>The vehicular safety application should be thoroughly tested before it is deployed in a real world to use. Simulator tool has been preferred over out door experiment because it simple, easy and cheap. VANET requires that a traffic and network simulator should be used together to perform this test. Many tools exist for this purpose but most of them have the problem with the proper interaction. In this thesis, we aim at simulating vehicular networks with external stimulus to analyze its effect on wireless communication but to do this job a good simulator is also needed. So we will first debate on the shortcoming of current simulators and come up with our own recommendations to perform our simulation.</p>

<p>This thesis considers several different techniques for optimizing Monte Carlo simulations. The Monte Carlo system used is Penelope but most of the techniques are applicable to other systems. The two mayor techniques are the usage of the graphics card to do geometry calculations, and raytracing. Using graphics card provides a very efficient way to do fast ray and triangle intersections. Raytracing provides an approximation of Monte Carlo simulation but is much faster to perform. A program was also written in order to have a platform for Monte Carlo simulations where the different techniques were implemented and tested. The program also provides an overview of the simulation setup, were the user can easily verify that everything has been setup correctly. The thesis also covers an attempt to rewrite Penelope from FORTAN to C. The new version is significantly faster and can be used on more systems. A distribution package was also added to the new Penelope version. Since Monte Carlo simulations are easily distributed, running this type of simulations on ten computers yields ten times the speedup. Combining the different techniques in the platform provides an easy to use and at the same time efficient way of performing Monte Carlo simulations.</p>

This study presents the results of using common two or three-parameter "default" distributions in place of "best fit distributions" in simulations of serial production lines with finite buffers and blocking. The default distributions used instead of the best-fit distribution are chosen such that they are non-negative, unbounded, and can match either the first two moments or the first three moments of the collected data. Furthermore, the selected default distributions must be commonly available (or easily constructed from) distributions in simulation software packages. The lognormal is used as the two-parameter distribution to match the first two moments of the data. The two-level hyper-exponential and three-parameter lognormal are used as three-parameter distributions to match the first three moments of the data. To test the use of these distributions in simulations, production lines have been separated into two major classes: automated and manual. In automated systems the workstations have fixed processing times and random time between failures, and random repair times. In manual systems, the workstations are reliable but have random processing times. Results for both classes of lines show that the differences in throughput from simulations using best-fit distributions and two parameter lognormal is small in some cases and can be reduced in others by matching the first three moments of the data. Also, different scenarios are identified which lead to higher differences in throughput when using a two-parameter default distribution. / Graduation date: 2004

With the success of the CounterDataFlow Pipeline microarchitecture developed by Oregon State University, there is increasing demand for a highly flexible high-level simulator modeling tool to support the further expansions and studies of the Counterflow pipeline processors family. This work examines the implementation of a Java-based execution-driven simulator modeling tool, bBlocks, which gains flexibility by identifying the independent parts in a micro system and partitioning them into reusable blocks. Two simulators have been constructed to demonstrate the possibility of bBlocks. / Graduation date: 2001

Molecular dynamics is a technique in which the trajectories of a group of particles are calculated as a function of time by integrating the equations of motion. In this thesis we study the use of molecular dynamics for atoms in a crystal. A model is introduced which describes interactions of a physical system with an external heat reservoir in molecular dynamics simulations. This is accomplished by the addition of a "virtual variable" to the Hamiltonian which is used to scale time. Aspects of this model are discussed and examples are presented for a simple system. Similarly, a constant pressure model is introduced in which additional virtual volume variables are added to the Hamiltonian. The volume and shape of the molecular dynamics cell are now free to vary. Simple examples are discussed. Aspects of the computer programs and the algorithms are explained. Particular attention is focused on the methods used to integrate the equations of motion and to calculate the coulomb interactions. Examples of simulations using a zirconium oxide crystal are presented. We study the effects of heat bath and pressure bath simulations, both separately and in combination. Various features of the behavior are investigated with the primary focus on phase changes, numerical errors, and parameters describing the heat and pressure baths. / Graduation date: 1996

Thesis (Ph. D.)--Oregon State University, 1972. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Since oil and gas production from conventional fields is decreasing, the produc-tion of unconventional hydrocarbon reservoirs is becoming imperative, where geo-mechanical responses play an important role. This research presents a methodology that starts exploring the inclusion of geomechanics in streamline simulations using a two-way explicit coupling approach between a reservoir and geomechanical simulators. This was done in an effort of conducting field-scale simulations considering the impact of geomechanical parame-ters on reservoir static properties, which affect ultimate recovery. Porosity, permeability, and porosity and permeability were used as the coupling parameters; the influence that they have on the process is problem-dependant as well. The results obtained from the two study cases presented, reveal that the per-formance of the approach is problem-dependent; the more complex the models are, the larger the geomechanical response is. One of the main aspects of this study was the limitations of the simulators. When software and hardware capacities improve, so will the results of the coupling ap-proach. Until then, more complex models should be tested, as well as more rigorous techniques, to improve the results presented here. / Petroleum Engineering

Site development in heavy and civil construction need to consider many rules such as ensuring proper drainage, prevention of flood, safety driving, optimizing earthwork, minimizing fleet travel distances, proper fleet matching and achieving high equipment utilization rates. In recent decades, numeral researchers have presented different solutions to improve this process; however they have been either too complicated to be practical or oversimplify the problem definition by ignoring critical facts. This thesis presents three advanced quantitative techniques to enhance current earthwork construction practices including: a modification of least squares method to optimize the earthwork, an application of transportation simplex method to minimize the fleet travel distance, and an earthwork construction process simulation to ensure the accuracy of earthwork operations analysis. The thesis also includes an actual case study to demonstrate the practicality and effectiveness of the proposed methodology. / Construction Engineering and Management