A proof of concept study into the working of network media capture and visualization through the use of Packet Capture in real-time. An application was developed that is able to capture tcp network packets; identify and display images in raw HTTP network traffic through the use of search, sort, error detection, timeout failsafe algorithms in real time. The application was designed for network administrators to visualize raw network media content together with its relevant network source \& address identifiers. Different approaches were tried and tested such as using Perl with GTK+ and Visual Studio C\# .Net. Furthermore two different types of image identification methods were used: raw magic string identification in pure tcp network traffic and HTTP Mime type identification. The latter being more accurate and faster. C# was seen as vastly superior in both speed of prototyping and final performance evaluation. The study presents a novel new way of monitoring networks on the basis of their media content through deep packet inspection

The target tracking system of an IR (InfraRed) guided missile is constantly subjected to disturbances due to the linear and angular motion of the missile. To diminish these LOS (Line Of Sight) disturbances the seeker of the missile can be built from a free gyroscope mounted in a very low friction suspension. The ability of the spinning gyroscope to maintain its direction relative to an inertial frame is used to stabilize the seeker LOS while tracking a target. The tracking velocity of the seeker, i.e. its angular velocity, is controlled by a feedback control unit where the signal from the IR detector is used as input. The electrical driven actuator consists of a set of coils and a magnet on the gyroscope. The purpose of this thesis is to develop a real-time model of the seeker gyroscope in an existing IR MANPAD (MAN Portable Air Defense) missile. The aim is a model that is able to simulate the real system with consideration to the tracking velocity. The model should also be integrated into a hybrid simulator environment. With relatively good knowledge of the system and its subsystems an initial physical modelling approach was used where elementary equations and accepted relations were assembled to describe the mechanism of the subsystems. This formed the framework of the model and gave a good foundation for further modelling. By using experimentation and more detailed system knowledge the initial approach could be developed and modified. Necessary approximations were made and unknown parameters were determined through system identification methods. The model was implemented in MATLAB Simulink. To make it suitable for real-time operation Real-Time Workshop was used. The model design was evaluated in simulations where the tracking performance could be tested for different positions of the gyroscope. The results where satisfying and showed that the model was able to reproduce the output of the system well considering the speed of the model and the approximations made. One important reason that good results can be achieved with a relatively simple model is that the seeker is limited to small rotations. The model can be tuned to operate in a smaller range and the complexity can be kept low. A weakness of the model is that the output error increases for wide angles.

To render outdoor scenes with lots of vegetation in real time is a big challenge. This problem has important applications in the areas of visualization and simulation. Some progress has been made the last years, but a previously unsolved difficulty has been to combine high rendering quality with abundant variation in scenes. I present a method to mathematically generate and render vegetation in real time, with implementation in the scene graph Gizmo3D. The most important quality of the method is its ability to render scenes with many unique specimens with very low aliasing. To obtain real time performance, a hierarchical level-of-detail scheme (LOD- scheme) is used which facilitates generation of vegetation in the desired level- of-detail on the fly. The LOD-scheme is texture-based and uses textures that are common for all specimens of a whole species. The most important contribution is that I combine this LOD-scheme with the use of semi- transparency, which makes it possible to obtain low aliasing. Scenes with semi-transparency require correct rendering order. I solve this problem by introducing a new method for approximate depth sorting. An additional contribution is a variant of axis-aligned billboards, designated blob, which is used in the LOD-scheme. Furthermore, building blocks consisting of small branches are used to increase generation performance.

Switched Ethernet is an Ethernet LAN that uses switches to connect individual nodes. This is popular because of its effective and convenient way of extending the bandwidth of existing Ethernets. Switched Ethernet is being considered by the industry community because of its open standardization, cost effectiveness, and the support for higher data rates up to 10Gbps. Even though many special-purposed solutions were proposed to support time constrained communication over Switched Ethernet, still there were some doubts about the real time handling capability of Switched Ethernet. To achieve reliable transmission guarantees for real time traffic over Switched Ethernet, it is important to measure the performance of Switched Ethernet networks for real time communication. In this thesis work we have observed the average end-to-end packet delay for real time traffic over a Switched Ethernet by simulation, which is very much essential for real time communication in industrial applications, where the communication is time-deterministic. In our thesis we used FCFS priority queuing in both the source nodes and switch. In this thesis we also discussed about the feasibility analysis for fixed sized frames and some traffic handling methods. We used 100mbp/s single full duplex Ethernet switch for our simulation. Finally simulation analysis and simulation results are discussed. Our purpose of simulation of Switched Ethernet networks is of good importance for the real time industrial applications.

In this thesis, we explore the topic of designing an architecture and processing algorithms for a multi-agent system, where agents need to address potential unexpected events in the environment, operating under soft real-time constraints. We first develop a classification of unexpected events into Opportunities, Barriers and Potential Causes of Failure, and outline the interaction required to support the allocation of tasks for these events. We then propose a hybrid architecture to provide for agent autonomy in the system, employing a central coordinating agent. Certain agents in the community operate autonomously, while others remain under the control of the coordinating agent. The coordinator is able to determine which agents should form teams to address unexpected events in a timely manner, and to oversee those agents as they perform their tasks. The proposed architecture avoids the overhead of negotiation amongst agent teams for the assignment of tasks, a benefit when operating under limited time and resource constraints. It also avoids the bottleneck of having one coordinating agent making all decisions before work can proceed in the community, by allowing some agents to work independently. We illustrate the potential usefulness of the framework by describing an implementation of a simulator loosely based on that used for the RoboCup Rescue Simulation League contest. The implementation provides a set of simulated computers, each running a simple soft real-time operating system. On top of this basic simulation we implement the model described above and test it against two different search-and-rescue scenarios. From our experiments, we observe that our architecture is able to operate in dynamic and real-time environments, and can handle, in an appropriate and timely manner, any unexpected events that occur. We also comment on the value of our proposed approach for designing adjustable autonomy multi-agent systems and for specific environments such as robotics, where reducing the overall level of communication within the system is crucial.

In order to control any system one needs to know the system's current state. In many real-world scenarios the state of the system cannot be determined with certainty due to the sensors being noisy or simply missing. In cases like these one needs to use probabilistic inference techniques to compute the likely states of the system and because such cases are common, there are lots of techniques to choose from in the field of Artificial Intelligence. Formally, we must compute a probability distribution function over all possible states. Doing this exactly is difficult because the number of states is exponential in the number of variables in the system and because the joint PDF may not have a closed form. Many approximation techniques have been developed over the years, but none ideally suited the problem we faced. Particle filtering is a popular scheme that approximates the joint PDF over the variables in the system by a set of weighted samples. It works even when the joint PDF has no closed form and the size of the sample can be adjusted to trade off accuracy for computation time. However, with many variables the size of the sample required for a good approximation can still become prohibitively large. Factored particle filtering uses the structure of variable dependencies to split the problem into many smaller subproblems and scales better if such decomposition is possible. However, our problem was unusual because some normally independent variables would become strongly correlated for short periods of time. This dynamically-changing dependency structure was not handled effectively by existing techniques. Considering variables to be always correlated meant the problem did not scale, considering them to be always independent introduced errors too large to tolerate. It was necessary to develop an approach that would utilize variables' independence whenever possible, but not introduce large errors when variables become correlated. We have developed a new technique for monitoring the state of the system for a class of systems with context-specific correlations. It is based on the idea of caching the context in which correlations arise and otherwise keeping the variables independent. Our evaluation shows that our technique outperforms existing techniques and is the first viable solution for the class of problems we consider.

Hardware-in-the-Loop (HIL) test platform for planetary rovers was designed, fabricated and tested in the present work. The ability for planetary rover designers and mission planners to estimate the rover’s performance through software simulation is crucial. HIL testing can further the benefits of software simulations by allowing designers to incorporate hardware components within traditionally pure software simulations. This provides more accurate performance results without having access to all hardware components, as would be required for a full prototype testing. The test platform is designed with complete modularity such that different types of tests can be performed for varying types of planetary rovers and in different environments. For demonstrating the operation of the test platform, however, the power system operation of a solar powered rover was examined. The system consists of solar panels, a solar charge controller, a battery, a DC/DC converter, a DC motor and a flywheel. In addition, a lighting system was designed to simulate the solar radiation conditions solar panels would experience throughout a typical day. On the software side, a library of component models was developed within MapleSim and model parameters were tuned to match the hardware on the test bench. A program was developed for real-time simulations within Labview allowing communication between hardware components and software models. This program consists of all the component models, hardware controls and data acquisitioning. The GUI of this program allows users to select which component is to be tested and which component is to be simulated, change model parameters as well as see real time sensor measurements for each component. A signal scaling technique based on non-dimensionalization is also presented, which can be used in an HIL application for obtain scaling factors to ensure dynamic similarity between two systems. A demonstration of power estimation was performed using the pure software model simulations as well as the pure hardware testing. Hardware components were then added into the software simulation progressively with results showing better accuracy as hardware is added. The rover’s power flow was also estimated under different load conditions and seasonal variation. These simulations clearly demonstrate the effectiveness of an HIL platform for testing a rover’s hardware performance.

Debugging is an important phase in the embedded software development cycle because of its high proportion in the overall cost in the product development. Debugging is difficult for real-time applications as such programs are time-sensitive and must meet deadlines in often a resource constrained environment. A common approach for real-time systems is to monitor the execution instead of stepping through the program, because stepping will usually violate all deadline constraints. We consider a time-triggered approach for program monitoring at runtime, resulting in bounded and predictable overhead. In time-triggered execution monitoring, a monitor runs as a separate process in parallel with an application program and samples the program's state periodically to evaluate a set of properties. Applying this technique in computing systems, results in bounded and predictable overhead. However, the time-triggered approach can have high overhead depending on the granularity of the monitoring effort. To reduce this overhead, we instrument the program with markers that will require to sample less frequently and thus reduce the overhead. This leads to interesting problems of (a) where to place the markers in the code and (b) how to manipulate the markers. While related work investigates the first part, in this work, we investigate the second part. We investigate different instrumentation schemes and propose two new schemes based on bitvectors that significantly reduce the overhead for time-triggered execution monitoring. Time-triggered execution monitoring suffers from several drawbacks such as; the time-triggered monitor requires certain synchronization features at the operating system level and may suffer from various concurrency and synchronization dependencies in a real-time setting. Furthermore, the time-triggered execution monitoring scheme requires the embedded environment to provide multi-tasking features. To address the aforementioned problems, we propose a new method called time-triggered self-monitoring, where the program under inspection is instrumented, so that it self-samples its state in a periodic fashion without requiring assistance from an external monitor or an internal timer. The experimental results show that a time-triggered self-monitored program performs significantly better in terms of execution time, binary code size, and context switches when compared to the same program monitored by an external time-triggered monitor.

This research is to carry out an experimental study to examine and verify the effectiveness of the control algorithms and strategies developed at the Advanced Engineering Design Laboratory (AEDL). For this purpose, two objectives are set to be achieved in this research. The first objective is to develop a generic experiment environment (test bed) such that different control approaches and algorithms can be implemented on it. The second objective is to conduct an experimental study on the examined control algorithms, as applied to the above test bed. <p>To achieve the first objective, two main test beds, namely, the real-time controllable (RTC) mechanism and the hybrid machine, have been developed based on a two degree of freedom (DOF) closed-loop five-bar linkage. The 2-DOF closed-loop mechanism is employed in this study as it is the simplest of multi-DOF closed-loop mechanisms, and control approaches and conclusions based on a 2-DOF mechanism are generic and can be applied to a closed-loop mechanism with a higher number of degrees of freedom. The RTC mechanism test bed is driven by two servomotors and the hybrid machine is driven by one servomotor and a traditional CV motor. To achieve the second objective, an experimental study on different control algorithms has been conducted. The Proportional Derivative (PD) based control laws, i.e., traditional iii PD control, Nonlinear-PD (NPD) control, Evolutionary PD (EPD) control, non-linear PD learning control (NPD-LC) and Adaptive Evolutionary Switching-PD (AES-PD) are applied to the RTC mechanism; and as applied to the Hybrid Actuation System (HAS), the traditional PD control and the SMC control techniques are examined and compared. <p> In the case of the RTC mechanism, the experiments on the five PD-based control algorithms, i.e., PD control, NPD control, EPD, NPD-LC, and AES-PD, show that the NPD controller has better performance than the PD controller in terms of the reduction in position tracking errors. It is also illustrated by the experiments that iteration learning control (ILC) techniques can be used to improve the trajectory tracking performance. <p>However, AES-PD showed to have a faster convergence rate than the other ILC control laws. Experimental results also show that feedback ILC is more effective than the feedforward ILC and has a faster convergence rate. In addition, the results of the comparative study of the traditional PD and the Computed Torque Control (CTC) technique at both low and high speeds show that at lower speeds, both of these controllers provide similar results. However, with an increase in speed, the position tracking errors using the CTC control approach become larger than that of the traditional PD control. In the case of the hybrid machine, PD control and SMC control are applied to the mechanism. The results show that for the control of the hybrid machine and the range of speed used in this experimental study, PD control can result in satisfactory performance. However, SMC proved to be more effective than PD control.

Winter wheat (<i>Triticum aestivum</i> L.), seeded in the fall, cold acclimates when exposed to low fall temperatures. Growth resumes in spring, culminating in early summer harvest. Winter wheat yield is generally 20-25% higher than spring wheat. However, winter damage/kill can reduce its yield. A better understanding of the cold acclimation/tolerance process could help in the development of improved breeding strategies for winter wheat hardiness. Transcriptional activators and specific cold regulated (COR) genes are induced as a result of exposure to low temperatures. Thus, the objective of this study was to determine the quantitative expression of three COR genes (Wcs120, Wcor410 and Wcor14b) and one transcriptional activator (WCBF1) in field-grown wheat using real-time PCR and to establish any association with LT50 (temperature at which 50% of plants are killed). Winter Norstar (vrn-A1/vrn-A1), spring Manitou (Vrn-A1/Vrn-A1) and two near-isogenic lines (Spring Norstar (Vrn-A1/vrn-A1) and Winter Manitou (vrn-A1/vrn-A1), respectively) were used in these studies. Plants were sampled on three dates (Sept. 29, Oct. 12 and Oct. 26) in the fall of 2004. Accumulation of WCBF1 transcripts was highest in Norstar, but in all four genotypes there was an increase in transcripts by the second sampling date, followed by a decline on the third sampling date. Wcs120 transcripts increased from the first to the third sampling date in Norstar, Spring Norstar and Winter Manitou, but increased to the second sampling date and decreased by the third in Manitou. For Wcor14b, generally there was an increase to the second sampling date, followed by a decrease or steady levels on the third. Wcor410 showed a similar pattern, except for Spring Norstar wherein transcript levels increased by the third sampling date. With the exception of Wcor410 in Manitou, the Vrn-A1 locus affected gene expression in all genotypes. However, only Wcs120 expression followed the low-temperature tolerance pattern in these genotypes.