The dramatic popularity of graph database has resulted in a growing interest in graph queries. Two major topics are included in graph queries. One is based on structural relationship to find meaningful results, such as subgraph pattern match and shortest-path query. The other one focuses on semantic-based query to find question answering from knowledge bases. However, most of these queries take knowledge graphs as flat forms and use only normal relationship to mine these graphs, which may lead to mistakes in the query results. In this thesis, we find hierarchical relationship in the knowledge on their semantic relations and make use of hierarchical relationship to query on knowledge graphs; and then we propose a meaningful query and its corresponding efficient query algorithm to get top-k answers on hierarchical knowledge graphs. We also design algorithms on distributed frameworks, which can improve its performance. To demonstrate the effectiveness and the efficiency of our algorithms, we use CISCO related products information that we crawled from official websites to do experiments on distributed frameworks.

According to World Health Survey, there are 785 million (15.6%) people in the world that live with a disability. It is a well-known fact that lack of access to public transportation is a barrier for people with disabilities in seeking work or accessing health care. In this research, we seek to increase access to public transportation by introducing a virtual pre-travel training system that enables people with disabilities to get familiar with a public transportation venue prior to arriving at the venue. Using this system, users establish a mental map of the target environment prior to their arrival to the physical space, increasing their confidence and therefore increasing their chances of using public transportation. First, we have to guarantee that all navigation instructions sent to our training system are correct. Since the number of navigation instruction increases dramatically, instruction validation becomes a challenge. We propose a video game based validation tool which includes a game scene that represents in 2D the physical environment and uses a game avatar to verify the navigation instructions automatically in the game scene. The avatar traverses the virtual space following the corresponding navigation instructions. Only in case that it successfully reaches the planned destination, the current navigation instruction can be considered as correct. Then, we introduce a virtual reality based pre-travel wayfinding training system to assist people with disabilities to get familiar with a venue prior to their arrival at the physical space, which provides two modes: 1) Self-Guided mode in which the path between a source and a destination is shown to the user from third person perspective, and 2) Exploration mode in which the user explores and interacts with the environment. In the end, we have implemented visual analytics tools that track and evaluate trainees’ performance and help us optimize the game. These tools identify the difficulties faced by the trainees as well as obtain overall statistics on the trainees’ behavior in the indoor environment, helping us understand how to modify the system and adjust it to different classes of disabilities.

Interactive data visualizations must respond fluidly to user input to be effective, or so we assume. In fact it is unknown exactly how fast a visualization must run to present every facet within a dataset. An engineering team with limited resources is left with intuition and estimates to determine if their application performs sufficiently well. This thesis studies how latency affects users' comprehension of data visualizations, specifically 3D geospatial visualizations with large data sets. Subjects used a climate visualization showing temperatures spanning from the 19th to the 21st century to answer multiple choice questions. Metrics like their eye movements, time per question, and test score were recorded. Unbeknownst to the participants the latency was toggled between questions, subjugating frame rendering times to intervals between 33 1/3 and 200 milliseconds. Analysis of eye movements and question completion time and accuracy fail to show that latency has an impact on how users explore the visualization or comprehend the data presented. User fixation times on overlaid 2D visualization tools however are impacted by latency, although the fixation times do not significantly differ over 3D elements. The finding speaks to how resilient users are in navigating and understanding virtual 3D environments --- a conclusion supported by previous studies about video game latency.

One of the most important operating system topics, file systems, control how we store and access data and form a key point in a computer scientists understanding of the underlying mechanisms of a computer. However, file systems, with their abstract concepts and lack of concrete learning aids, is a confusing subjects for students. Historically at Cal Poly, the CPE 453 Introduction to Operating Systems has been on of the most failed classes in the computing majors, leading to the need for better teaching and learning tools. Tools allowing students to gain concrete examples of abstract concepts could be used to better prepare students for industry. The PolyFS Visualizer is a block level file system visualization service built for the PolyFS and TinyFS file systems design specifications currently used by some of professors teaching CPE 453. The service allows students to easily view the blocks of their file system and see metadata, the blocks binary content and the interlinked structure. Students can either compile their file system code with a provided block emulation library to build their disk on a remote server and make use of a visualization website or place the file mounted as their file system directly into the visualization service to view it locally. This allows students to easily view, debug and explore their implementation of a file system to understand how different design decisions affect its operation. The implementation includes three main components: a disk emulation library in C for compilation with students code, a node JS back-end to handle students file systems and block operations and a read only visualization service. We have conducted two surveys of students in order to determine the usefulness of the PolyFS Visualizer. Students responded that the use of the PolyFS visualizer helps with the PolyFS file system design project and has several ideas for future features and expansions.

Virtual reality is currently in the spotlight, attracting intense scrutiny by the press, technology companies, and consumers. After twenty years of dormancy, the technology has experienced a renaissance following advancements in both hardware and software. Most of these developments, and thus press attention, have been centered on entertainment. However, if the technology is going to continue to grow, it must be useful in a wide variety of situations. This paper explores the effectiveness of visualizing data in virtual reality in comparison to traditional presentations. In this thesis, we present an approach to displaying data in a virtual reality environment. We drew upon various visualization and design principles in two dimensions (2D) and extended and implemented them in three dimensions (3D). Finally, we experimented with animations to highlight how the immersive qualities of virtual reality could help direct the user's attention to important features. To verify our work, we tested users' ability to understand worldwide economic data represented as graphs. We measured the speed and accuracy of each subject's responses as they viewed the economic data in two environments: a virtual reality (VR) environment using the Oculus Rift to look at our 3D animated chart, and a more traditional environment with a series of 2D paper charts. We concluded that for newcomers to VR, 2D charts are faster and more accurate. However, 3D visualizations are more engaging and are superior when searching for certain kinds of information such as the highest and lowest values in a set.

Video games, and entertainment media have been developed for many years, and eliciting emotional experiences is an integral part of that process. Producing and editing game content in order to affect desired emotional experiences can be expensive and cumbersome to developers. This paper presents a study intended to show that such experiences can be affected with simple after-the-fact audio-visual effects. As subjects of the study, participants experience three different emotional states, fear, peace, and none, over three rounds and in three different game environments. They are given a simple narrative in each environment that directs them to gather various objects. The fear and peace emotional states are represented by carefully designed sets of simple audio-visual effects, while the none state represents the absence of any additional audio-visual effects. That states are randomly and non-repeatedly applied to the game environments for each participant. Over 50% of responses indicate proper emotions across emotion states for all levels, and rounds, and there are statistically significant effects between most emotional state comparisons. This means that it is indeed possible to induce emotional response with after-the-fact audio-visual effects, and it hints at future possibilities for drag-and-drop emotional experience filters

The convenience of mobile applications combined with the efficiency and effectiveness provided by technology has contributed to an increased interest in mobile applications. Local groups and non-profit organizations often utilize outdated, manual processes and don’t have the resources or time to look into improving these systems. For Cal Poly students and other members of the community, this means there is an opportunity to apply technical skills and school projects to address these inefficiencies. This work explores whether a better system can be developed to provide the functionality of the existing system and enhance the experience of users through technology, data tracking, and automation. Two apps demonstrate the application of technology to meet needs within the San Luis Obispo community: Poly Rides is an iOS and Android application that improves ridesharing for Cal Poly students. The idea stemmed from the Cal Poly Rideshare Facebook page, where the posting format for a ride is inconsistent, making it difficult to find a ride match. The Poly Rides app provides an improved user interface for posting, searching, and coordinating rides with other students. Its success has been validated through the popularity of the app. There were 3734 installations and 7925 messages sent as of May 27, 2016. Woods is an iOS application for iPhone, iPad, and Apple Watch that improves the care tracking process for dogs at Woods Humane Society. The previous technique involved updating a whiteboard to manage the information and care for the avail- able dogs. The whiteboard had inconsistent and limited information, was often out of date, and did not have room to list all of the dogs. An app was created which automatically pulls the dogs from the shelter database, provides more detailed information and instructions, and is available for volunteers on their personal devices. The results revealed a much larger and more positive impact than originally anticipated; volunteers reported feeling more confident providing appropriate care to the dog (65.9%) and that they have more trust in the dogs’ information (52.3%). Of staff and volunteers, 83.9% prefer the app over the whiteboard and 10.7% have no preference. Dog breed, size, age, and photo, details not available on the whiteboard, were reported to be “Very” or “Extremely” important by 56.8% of volunteers. This thesis describes some important requirements for developing community service mobile applications, offers suggestions for facilitating the development of a high quality product, and lists some useful resources for iOS development. Both apps not only reach their goal of improving a manual process in the local community, but also have the potential to improve and impact other communities around the world.

There are approximately 23.14 billion IoT(Internet of Things) devices currently in use worldwide. This number is projected to grow to over 75 billion by 2025. Despite their ubiquity little is known about the security and privacy implications of IoT devices. Several large-scale attacks against IoT devices have already been recorded. To help address this knowledge gap, we have collected a year’s worth of network traffic and power data from 16 common IoT devices. From this data, we show that we can identify different smart speakers, like the Echo Dot, from analyzing one minute of power data on a shared power line.

Massively Multiplayer Online Role Playing Games (MMORPGs) are a prominent genre in today's video game industry with the most popular MMORPGs generating billions of dollars in revenue and attracting millions of players. As they have grown, they have become a major target for both technological research and sociological research. In such research, it is nearly impossible to reach the same player scale from any self-made technology or sociological experiments. This greatly limits the amount of control and topics that can be explored. In an effort to make up a lacking or non-existent player-base for custom-made MMORPG research scenarios A.I. agents, impersonating human players, can be used to "bootstrap" the research scenario to reach the necessary massive number of players that define the game genre. This thesis presents a system that makes its human players and A.I. players indistinguishable while preserving the basic characteristics of a typical MMORPG. To better achieve identical perception of human and A.I. players, our system centers around the collection, sharing, and exchange of information while limiting the means of expression and actions of players. A gameplay scenario built on the Panoptyk engine was constructed to imitate gameplay experienced in major MMORPGs. We conducted a user-study where subjects play through the scenario with a varying number of A.I. players unknown to them. Three versions of the scenario were created to assess how indistinguishable human and A.I. players were and vice versa. We found, across 24 participants, there were 32% correct identifications, 30% incorrect identifications, and 38% answers of "I don't know". This was broken down into 20% correct identifications, 42% incorrect identifications, and 38% answers of "I don't know" for bot characters and 46% correct identifications, 16% incorrect identifications, and 38% answers of ``I don't know'' for human characters.

Computing complex lighting simulations such as global illumination is a computationally intensive task. Various real time solutions exist to approximate aspects of global illumination such as shadows, however, few of these methods offer single pass rendering solutions for soft shadows (self and other) and inter-reflections. In contrast, Precomputed Radiance Transfer (PRT) is a real-time computer graphics technique which pre-calculates an object's response to potential incident light. At run time, the actual incident light can be used to quickly illuminate the surface, rendering effects such as soft self-shadows and inter-reflections. In this thesis, we show that by calculating PRT lighting coefficients densely over a surface as texture data, additional surface detail can be encoded by integrating other computer graphics techniques, such as normal mapping. By calculating transfer coefficients densely over the surface of a mesh as texture data, greater fidelity can be achieved in lighting coarse meshes than simple interpolation can achieve. Furthermore, the lighting on low polygon objects can be enhanced by drawing surface normal and occlusion data from highly tessellated, detailed meshes. By applying such data to a decimated, simplified mesh, a more detailed and visually pleasing reconstruction can be displayed for a lower cost. In addition, this thesis introduces Hierarchical PRT, which extends some surface effects, such as soft shadows, between objects. Previous approaches to PRT used a more complex neighborhood transfer scheme in order to extend these lighting effects. Hierarchical PRT attempts to capture scene information in a tree data structure which represents coarse lighting relationships between objects. Potential occlusions can be found at run time by utilizing the same spherical harmonic representation used to represent surface lighting to instead store light "filters" between scene tree nodes. Such "filters" can be combined over a set of nodes in the scene to obtain the net shadowing of an object with good performance. We present both visually pleasing results on simplified meshes using normal mapping and textured PRT and initial results using Hierarchical PRT that captures low frequency lighting information for a small number of dynamic objects which shadow static scene objects with good results.