Peer-to-Peer (P2P) systems are emerging as a new form of distributed computing with a strong emphasis on self-organization, decentralization, and autonomy of the participating nodes. The characteristics of self-organization, autonomy, and decentralization allow for highly adaptive, robust, and scalable networks, making P2P an increasingly interesting way to design distributed systems. <p>Since the deployment of P2P systems involves significant resources, e.g., hundreds of hosts and users, it is often not possible to run realistic tests prior to the rollout of the system. Consequently, simulation is the only realistic approach for testing or predicting the behavior of large P2P networks. However, the majority of the existing simulators tend to provide limited flexibility in simulating the details of the users, application, protocol, and physical network. <p>In this research, the impact of user behavior, protocol, and physical network characteristic on the overall P2P system are being observed. The aim is to investigate the importance of simulating P2P systems in such detail.

The objective of this thesis was to better understand the patterns of IV-pump use throughout the hospital in order to provide guidance to the hospital on alternative pump management methods. In the current system, when the number of available pumps in a department was fewer than the number of pumps required for patient care, the department encountered shortage. In most cases, the personnel were not clear on where available pumps might be stored and had to search for free pumps throughout the hospital. <br /><br /> The system was thoroughly studied and the necessary data were collected. A model reflecting the current flow of patients and pumps was developed. This model was operationalized by constructing a simulation model. The model presented the flow through the hospital on a daily basis. <br /><br /> The output of the simulation model provided the daily number of pumps in use in each of the departments and the distribution of pump use for each department, separately, and overall. Using these distributions, the number of pumps required in each department if maintaining a supply of pumps was quantified to meet certain service levels. In addition, the number of pumps required in the system if the pumps were all shared, was also obtained. It was concluded that the actual number of pumps required in the system is fewer than the number of pumps existing in the hospital. This conclusion confirmed that long searches for free pumps were not due to insufficient quantity of pumps, but were solely due to the behaviour of hoarding extra pumps when available. The simulation also provided the number of pumps short per day and the number of pumps in excess per day, by department. <br /><br /> Two pump management alternatives were suggested to the hospital. The first alternative was to utilize a centralized pool to keep all shared pumps when not in use. The second alternative was to install RFID technology throughout the hospital and equip all pumps with RFID tags so that they could be easily located. The three pump management systems (current, central pooling, and RFID) were compared, and the advantages and disadvantages of each of the alternative techniques were discussed.

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. 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.

The aim of this project has been to develop a new method that can be used for optimising the sequences of operations in flexible manufacturing cells. The method combines existing methods and available software tools from three research areas, optimisation, flexibility and virtual manufacturing. This method is named SIMBOSeer and it combines genetic algorithms in discrete event simulation together with continuous robot simulation. SIMBOSeer has been implemented at an existing workcell at Volvo Powertrain, Skövde, and it has successfully shown to be able to find possible improvements of the sequences of operations. SIMBOSeer has shown to be a successful combination of different virtual manufacturing tools. It has a great ability to find an optimal solution of the sequence of operations in a flexible manufacturing cell. SIMBOSeer not only gives a fast answer on how to produce different variants it also offers the possibility to generate the robot code automatically.

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.

Simulation plays a key role in the computer-aided design of systems, primarily because it helps in catching design bugs at an early stage and in quickly ruling out many unreasonable options in the design space. There is a wealth of tools and languages that have been proposed over the years for the design and verification of hybrid systems and most of them provide 3D visualization utility for facilitating design process. However, their visualization systems often rely on some external configuration files written in naive 3D APIs like VRML or Java3D and complicated connections have to be established between the simulation data and the visualization. Numerous efforts have to be invested in visualization related modeling and certain level of understanding of the low level 3D libraries are needed. Thus it is not an easy job for non-professions to build a 3D visualization. In this thesis we explore the idea that in a hybrid system model, almost all the information need for visualization is already in place. This means that very few annotation should be enough to fully specify a useful 3D visualization. Based on this idea, we propose a lightweight 3D visualization framework which allows the user to expresses the three-dimensional object in a high level and abstract way and to take advantage of the data already in the simulation. We evaluate our approaching by building a prototype extension of modeling language called Acumen. The result of this thesis work is included in Acumen's official release version that can be download at www.acumen-language.org. To build a 3D visualization in Acumen, only very few annotations need to be added to the simulation model and are included inside one reserved variable. Non-professions like students who are studying Cyber-physical systems can easily use this tool to visualize their models in Acumen without any prerequisite knowledge regarding 3D visualization technology. We also developed a number of benchmarks to test the correctness and functionality of Acumen3D. Besides, as a lager case study into the expressivity of Acumen and its visualizaiton efficiency, we developed a simplified model of a Ping Pong game. We gained experience about how to model complex hybrid system in Acumen. Moreover by comparing modeling such a hybrid system in Java3D and in Acumen3D, we find concrete evidence that modelling it in Acumen3D is easier in that of less code and less prerequisite knowledge and more supporting built in functions.

The objective of this thesis was to better understand the patterns of IV-pump use throughout the hospital in order to provide guidance to the hospital on alternative pump management methods. In the current system, when the number of available pumps in a department was fewer than the number of pumps required for patient care, the department encountered shortage. In most cases, the personnel were not clear on where available pumps might be stored and had to search for free pumps throughout the hospital. <br /><br /> The system was thoroughly studied and the necessary data were collected. A model reflecting the current flow of patients and pumps was developed. This model was operationalized by constructing a simulation model. The model presented the flow through the hospital on a daily basis. <br /><br /> The output of the simulation model provided the daily number of pumps in use in each of the departments and the distribution of pump use for each department, separately, and overall. Using these distributions, the number of pumps required in each department if maintaining a supply of pumps was quantified to meet certain service levels. In addition, the number of pumps required in the system if the pumps were all shared, was also obtained. It was concluded that the actual number of pumps required in the system is fewer than the number of pumps existing in the hospital. This conclusion confirmed that long searches for free pumps were not due to insufficient quantity of pumps, but were solely due to the behaviour of hoarding extra pumps when available. The simulation also provided the number of pumps short per day and the number of pumps in excess per day, by department. <br /><br /> Two pump management alternatives were suggested to the hospital. The first alternative was to utilize a centralized pool to keep all shared pumps when not in use. The second alternative was to install RFID technology throughout the hospital and equip all pumps with RFID tags so that they could be easily located. The three pump management systems (current, central pooling, and RFID) were compared, and the advantages and disadvantages of each of the alternative techniques were discussed.

A computer simulation program was previously developed by the researcher which determines a theoretically optimal movement pattern for the free throw in wheelchair basketball. The purpose of this study was to evaluate the external validity of the optimization program by examining whether the knowledge of the optimal movement pattern facilitates performance of the free throw in wheelchair basketball. </p><p>In a pilot study, four able-bodied players from the Saskatchewan Wheelchair Basketball Mens Team were invited to participate on one occasion. These participants were videotaped shooting free throws to provide knowledge of an expert wheelchair free throw movement pattern. Using video analysis, it was found that the release conditions used by this group were very similar to those predicted to be optimal. This lent support to the predicted optimal movement pattern being an actual optimal movement pattern for the free throw in wheelchair basketball. In the primary study, thirty-three able-bodied male participants were randomly assigned to three groups: a no-feedback group; a video-feedback group; and an optimal pattern feedback group. The participants performed wheelchair basketball free throw training for three days over one week. The no-feedback group simply shot free throws from a wheelchair, whereas the video-feedback group viewed video of their previous free throws, and the optimal pattern group viewed video of their previous free throws with an optimal free throw pattern superimposed. The participants also completed a pretest one week before and a retention test one week after the training period. </p> <p>A repeated measures ANOVA was used to test for significant differences between the three training groups in free throw success in wheelchair basketball over each testing occasion. The statistical analyses indicated that there were no differences in free throw success between the group that had knowledge of their personalized optimal movement pattern when compared to the groups that received either no-feedback or video-feedback (p<0.05). </p> <p>Video analysis revealed that the wheelchair free throw movement pattern of participants in the optimal pattern group changed substantially from the pretest to the post-test. This suggests that the participants in the optimal pattern group were making progress towards their optimal movement patterns, but had not yet mastered the movement pattern.

Peer-to-Peer (P2P) systems are emerging as a new form of distributed computing with a strong emphasis on self-organization, decentralization, and autonomy of the participating nodes. The characteristics of self-organization, autonomy, and decentralization allow for highly adaptive, robust, and scalable networks, making P2P an increasingly interesting way to design distributed systems. <p>Since the deployment of P2P systems involves significant resources, e.g., hundreds of hosts and users, it is often not possible to run realistic tests prior to the rollout of the system. Consequently, simulation is the only realistic approach for testing or predicting the behavior of large P2P networks. However, the majority of the existing simulators tend to provide limited flexibility in simulating the details of the users, application, protocol, and physical network. <p>In this research, the impact of user behavior, protocol, and physical network characteristic on the overall P2P system are being observed. The aim is to investigate the importance of simulating P2P systems in such detail.

Free volume and free volume distribution have long been used to explain differences in the gas transport properties of polymeric materials. However, only a few experimental techniques allow a comprehensive evaluation of polymeric void space. Through the use of computer simulations, the free volume was characterized of two polyester systems used for beverage packaging and polynorbornene, a unique polymer with possible applications in both microelectronic fabrication and membrane separations. Delaunay Tessellation was used to calculate the fractional free volume (FFV) of both polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) molecular models. It was hypothesized that differences in the FFV distributions could be used to explain the higher experimental O2 solubility in PEN relative to PET. The analysis showed that there was no statistical difference between the FFV distributions for O2 sized penetrants. Clustering analysis was performed based upon the tetrahedra formed by Delaunay Tessellation to examine the connectivity of free volume pockets. These results show that there is a statistically larger number of small (containing less than 10 tetrahedra/cluster and between 20-30 and #506;3 in volume) clusters in PEN. It is this difference in small clusters which provides for the 30% higher O2 solubility in PEN. The free volume of a representative high molecular weight amorphous model of Hexafluroalcohol Subsituted Polynorbornene (HFA-PNB) was also characterized in to examine the shape of the free volume cavities and to draw correlations with the mean lifetime of ortho-positronium (o-Ps) from Positron Annihilation Lifetime Spectroscopy (PALS). Delaunay Tessellation and clustering analysis indicated that the free volume clusters in high molecular weight HFA-PNB are slightly non-spherical. Correcting lifetimes for the somewhat non-spherical shape of these free volume clusters was insufficient to reproduce experimentally measured positron annihilation lifetimes because the clusters contained many tortuous connections within the clusters. Inclusion of this connectivity information does produce a more accurate estimate of the measured life times. This indicates that the o-Ps does sample many tetrahedra in these static clusters, but does not freely sample every section of these clusters.