Fog computing is a distributed computing paradigm that brings data processing from remote cloud data centers into the vicinity of the edge of the network. The computation is performed closer to the source of the data, and thus it decreases the time unpredictability of cloud computing that stems from (i) the computation in shared multi-tenant remote data centers, and (ii) long distance data transfers between the source of the data and the data centers. The computation in fog computing provides fast response times and enables latency sensitive applications. However, industrial systems require time-bounded response times, also denoted as RT. The correctness of such systems depends not only on the logical results of the computations but also on the physical time instant at which these results are produced. Time-bounded responses in fog computing are attributed to two main aspects: computation and communication.    In this thesis, we explore both aspects targeting soft RT applications in fog computing in which the usefulness of the produced computational results degrades with real-time requirements violations. With regards to the computation, we provide a systematic literature survey on a novel lightweight RT container-based virtualization that ensures spatial and temporal isolation of co-located applications. Subsequently, we utilize a mechanism enabling RT container-based virtualization and propose a solution for orchestrating RT containers in a distributed environment. Concerning the communication aspect, we propose a solution for a dynamic bandwidth distribution in virtualized networks.

Public transportation provides people with access to education, employment, health and community activities. However, navigating inside public hubs for people with disabilities such as cognitive or mobility impairments can be very challenging and dangerous. With the rapid development of digital technology such as Smartphones and sensors, there are unprecedented opportunities to assist people with disabilities to conquer these challenges. In this research, we aim to create a two-step indoor navigation solution for users with different mobility and orientation abilities. In the first step, we developed a virtual reality-based pre-travel training module that enables users to familiarize themselves with the virtual environment which represents the physical environment. After users feel confident and familiar enough with the environment, they proceed to the second step in which they visit the physical environment and use our real-time navigation assistance module. The pre-travel training module is developed using a Unity-based 3D game and includes a virtual indoor environment that represents the physical environment. The game provides a navigation function that highlights the path between the user location and the chosen destination. Considering the unique needs of cognitive impaired users, we designed action training modules in the game environment which train the user to use the ticket machine, fare gate and call boxes. Such training modules help cognitive impaired users familiarize themselves with the environment as well as gain confidence to experience the physical environment. When the users are ready to visit the physical environment, they use our real-time navigation assistance module which includes the same 3D virtual environment developed for the pre-travel training module. This approach is particularly important for people with cognitive impairment since they cannot organize navigation cues effectively. Using the Bluetooth Low Energy (BLE) infrastructure in the environment, our localization algorithm can track the user location in real-time. Subsequently, the user’s location will be integrated into the game environment so that the navigation path between the user’s current location and the selected destination can be generated and visualized by the user on the fly.

Indirect lighting drastically increases the realism of rendered scenes but it has traditionally been very expensive to calculate. This has long precluded its use in real-time rendering applications such as video games which have mere milliseconds to respond to user input and produce a final image. As hardware power continues to increase, however, some recently developed algorithms have started to bring real-time indirect lighting closer to reality. Of specific interest to this paper, cloud-based rendering systems add indirect lighting to real-time scenes by splitting the rendering pipeline between a server and one or more connected clients. However, thus far they have been limited to static scenes and/or require expensive precomputation steps which limits their utility in game-like environments. In this paper we present a system capable of providing real-time indirect lighting to fully dynamic environments. This is accomplished by modifying the light gathering step in previous systems to be more resilient to changes in scene geometry and providing indirect light information in multiple forms, depending on the type of geometry being lit. We deploy it in several scenes to measure its performance, both in terms of speed and visual appeal, and show that it produces high quality images with minimum impact on the client machine.

Background. As computing power has increased over the years, larger parts of the digital graphics industries are moving towards using real-time rendering for their solutions. The fast iteration and visual response help make the creative processes and communication more accessible in both the desktop and smartphone markets. One noticeably growing area using real-time rendering is the communication between people and audiences using online chat applications with virtual avatars. As humans, social interaction is essential to every aspect of our health. The requirements of remote communications to satisfy the needs of social interaction are facial expressions. Facial expressions involve motion. Thus making real-time rendering mandatory for having facial expressions in computer-generated images. This thesis shows the performance result of having real-time procedural-generated eye features. Objectives. This thesis is based on an experiment by developing a data set of duration for computing different visual aspects of anime eyes, the aim is to help inform the creation of more complete and optimized shader solutions. The objectives of this thesis are to produce a profiling application, produce a collection of eye references, produce a collection of visual eye features, produce shaders based on the collections, and measure the time performance of the shaders. Method. Doing this experiment involves producing a profiling application in the C++ programming language using the OpenGL graphics API. The profiling application can render a set of shaders and measure time metrics. The experiment is executed on two different computers with different specifications. By gathering a collection of eye references from online resources, targeting popular media in the anime style, a collection of visual eye features can be established with common and unique attributes. The collections allow for the creation of a set of shaders that replicate the collected eye features. With the profiling application and shaders, a data collection of time metrics are composed. Results. The final results of the profiling experiment have a collection of 29 shaders representing different eye features. The profiling tests gave the results of how many milliseconds it took for a set number of frames to render each produced shader. This result is shown with the help of two different graphs for each computer that executed the experiment. Deconstructing the resulting data helps to analyze and distinguish interesting aspects. Conclusions. From the result of this thesis experiment, the conclusion can be made that an eye feature by itself is a fast process for the GPU to compute on its own. Aset of eye features combined to create a final eye shader including animation and eye tracking is a valid future work section regarding this thesis experiment.

In modern processor architectures, caches are widely used to shorten the gap between the processor speed and memory access time. However, caches are time unpredictable, especially the shared L2 cache used by different cores on multicore processors. Thus, it can significantly increase the complexity of worst-case execution time (WCET) analysis, which is crucial for real-time systems. This dissertation designs several time-predictable scratchpad memory (SPM) based architectures for both VLIW (Very Long InstructionWord) based single-core and multicore processors. First, this dissertation proposes a time predictable two-level SPM based architecture for VLIW based single-core processors, and an ILP (Integer Linear Programming) based static memory objects allocation algorithm is extended to support the multi-level SPMs without harming the time predictability of SPMs. Second, several SPM based architectures for VLIW based multicore processors are designed. To support these architectures, the dynamic memory objects allocation based partition, the static memory objects allocation based partition and the static memory objects allocation based priority L2 SPM strategy are proposed, which retain the characteristic of time predictability. Also, both the WCET and worst-case energy consumption (WCEC) of our SPM based single-core and multicore architectures are completely evaluated in this dissertation. Last, to exploit the load/store latencies that are statically known in this architecture, we study a SPM-aware scheduling method to improve the performance. Our experimental results indicate the strengths and weaknesses of each proposed architecture and allocation method, which offers interesting memory design options to enable real-time computing. The strength of the two-level architecture is its superior performance compared to the one-level architecture, while the strength of the one-level architecture is its simple implementation. Also, the two-level architecture with separated L1 SPM for each core better fits for the data-intensive real-time applications, which not only retains good performance but also achieves a higher bandwidth by accessing both instruction and data SPM at the same time. Compared to the static based strategies, the dynamic allocation based partition L2 SPM strategy offers the better performance on each core because of the reuse of SPM space at the run-time, but has much higher complexity. In addition, the experimental results show that the timing and energy performance of our proposed SPM based architectures are superior to the similar cache based and hybrid architectures. Meanwhile, our architectures can ensure time predictability which is desirable for the real-time systems.

This thesis deals with certain properties of real time operating systems (RTOS) Ardence PharLap ETS, WindRiver VxWorks and LabVIEW RT module. Three methodologies of RTOS quality comparison are proposed, two of which are practically tested with described experiments on CompactRIO hardware from NI. Furthermore, there is explained need for RTOS usage and experimental comparison of jitter error influence on total harmonic distortion THD defined by two definitions.

The goal of this thesis is how to implement the two different types of the electric alternate motors in ZYNQ-7000 device for MIL real-time simulation purposes. The chosen types of motors are BLDC motor and AC induction motor. Mathematics models of these motor, the necessary changes for implementation purposes and the way how the models were implemented in ZYNQ-7000 device are described in this work. Three different experimental MIL simulation, using these motors ae described at the end of this thesis.

<p>Distributed real-time systems are notoriously difficult to correctly design and construct [Pam as 1985]. The fundamental principles of concurrency, deadline driven scheduling, and reaction to external stimuli which underlie such systems are inherently complex. This difficulty is further exacerbated when applications based on these principles are distributed over a network. Academic instruction in this domain is challenging: while theoretical issues can be taught with traditional "pencil and paper" techniques, real-time programming skills require experience that can be best provided by a laboratory. To this end, the Computer Science Department at Virginia Tech created and built a laboratory, known as the Reactive Systems Laboratory (RSL), specifically designed to provide these practical experiences. This paper documents the decisions, designs, and equipment used to build this laboratory. Additionally, the low-level software systems required to operate the RSL are discussed. Finally, future directions for the laboratory are considered and some conclusions are drawn based on usage to-date.</p> / Master of Science

The goal of this work was to design fast and simple methods for processing point-cloud-data of urban areas for virtual reality applications. For the visualization of methods, we developed a simple renderer written in C++ and HLSL. The renderer is based on DirectX 11. For point-cloud processing, we designed a method based on height-histograms for filtering ground points out of point cloud. We also proposed a parallel method for point cloud segmentation based on the region growing algorithm. The individual segments are then tested by simple rules to check if it is or it is not corresponding to a predefined object.

The transmission of human pathogens by faecally contaminated fruit and vegetables is well established, but the burden of disease caused by foodborne pathogens is unknown. Fresh produce can be contaminated through the use of polluted irrigation water or by the handling of the produce by infected individuals either pre- or post harvest. There is very little known regarding the extent of viral contamination of irrigation water and fresh produce in South Africa. Noroviruses (NoV) and hepatitis A virus (HAV) are recognized as leading causes of foodborne viral disease. These viruses are transmitted predominantly via the faecal–oral route, primarily person-to-person by direct contact with an infected person, or indirectly by ingestion of contaminated food and water. The detection of enteric viruses in food or water is problematical and complex as many foodborne viruses, including HAV and NoV, cannot be readily isolated in cell culture. The aim of this investigation was to develop and optimise simple and efficient methods for the concentration and detection of NoV GII and HAV in irrigation water and fresh produce. These methods would then be applied to field samples of irrigation water and fresh produce to try and establish a link between viral contamination detected in irrigation water and that on associated irrigated fresh produce. The efficiency of different commercial real-time reverse transcriptase-polymerase chain reaction amplification kits for the realtime detection of HAV, NoV GI and NoV GII was assessed, and standard curves for the quantitative detection of these viruses were constructed using the most appropriate kit. Using two types of fresh produce, three different elution buffers, each at two pHs, with two different elution times were compared to establish which buffer was the most efficient for the extraction of viruses from the fresh produce. The tris-glycine beef extract buffer (pH 9.5) with an elution time of 20 minutes most efficient for the extraction of the selected enteric viruses from fresh produce. From April 2008 to November 2009, 86 irrigation water and 72 fresh produce samples were collected from commercial and subsistence farms, street vendors and commercial outlets. All the irrigation water and fresh produce samples were analysed for HAV, NoV GI and NoV GII. Overall, 16.3 % (13/86) and 12.5 % (9/72) of irrigation water and fresh produce samples tested positive for one or more human pathogenic viruses, namely NoV GII and HAV, respectively. Nucleotide sequence and phylogenetic analysis of the HAV and NoV GII strains identified clinically relevant viruses in the irrigation water and on the fresh produce. A direct link between contaminated irrigation water and contamination of fresh produce could not be established, but irrigation water was identified as a possible source of contamination of the fresh produce. The results also suggested that food handlers contributed significantly to the viral contamination of the fresh produce. This study highlights the potential health risk posed by fresh produce to consumers in South Africa and highlights the need for further in depth studies to quantify the risk to consumers. This study represents new data on the occurrence of enteric viruses in food and water in South Africa and is crucial for the development of effective intervention and control strategies for food safety in South Africa. Copyright / Dissertation (MSc)--University of Pretoria, 2011. / Medical Virology / unrestricted