Enterprise networks are traditionally mapped via layers two or three, providing a view of what devices are connected to different parts of the network infrastructure. A method was developed to map connections at layer four, providing a view of interconnected systems and services instead of network infrastructure. This data was graphed and displayed in a web application. The information proved beneficial in identifying connections between systems or imbalanced clusters when troubleshooting problems with enterprise applications.

Ray tracing is a well-know technique for producing realistic graphics. However, the time necessary to generate images is unacceptably long. When producing the many frames that are necessary for animations, the time is magnified. Many methods have been proposed to reduce the calculations necessary in ray tracing. Much of the effort has attempted to reduce the number of rays cast or to reduce the number of intersection calculations. Both of these techniques exploit spatial coherence. These acceleration techniques are expanded not only to exploit spatial coherence but also to exploit temporal coherence in order to reduce calculations by treating animation information as a whole as opposed to isolating calculations to each individual frame. Techniques for exploiting temporal coherence are explored along with associated temporal bounding methods. By first ray tracing a temporally expanded scene, we are able to avoid traversal calculations in associated frames where object intersection is limited. This reduces the rendering times of the associated frames.

This paper involves implementing a forward path tracer in C++ using OpenMP in order to examine the effects of Samples per Pixel (SPP) on output images given in different environments. Output images of scenes with different amounts of lighting are rendered in different resolutions. These renders are timed and output images are saved to files. Looking at these results, varying the SPP-value results in drastic changes in render time and image quality. Such performance differences ultimately affect the possibilities for the developed path tracer and its applications. / Denna rapport undersöker effekten av Samples per Pixel (SPP) på renderade bilder genom implementerandet av en forward path tracer i C++. Bilderna består av olika scener med olika ljustyrkor i olika bildstorlekar. Dessa resultat visar att ändring av SPP-värden leder till drastiska förändringar i bildkvalitet och renderingstid. Dessa faktorer påverkar i slutändan möjligheterna till vidare appliceringar av path tracer implementationen.

Large scale Internet services are increasingly implemented as distributed systems in order to achieve fault tolerance, availability, and scalability. When requests traverse multiple services, end-to-end metrics no longer tell a clear picture. Distributed tracing emerged to break down end-to-end latency on a per service basis, but only answers where a problem occurs, not why. From user research we found that root-cause analysis of performance problems is often still done by manually correlating information from logs, stack traces, and monitoring tools. Profilers provide fine-grained information, but we found they are rarely used in production systems because of the required changes to existing applications, the substantial storage requirements they introduce, and because it is difficult to correlate profiling data with information from other sources. The proliferation of modern low-overhead profilers opens up possibilities to do online always-on profiling in production environments. We propose Protractor as the missing link that exploits these possibilities to provide distributed profiling. It features a novel approach that leverages service meshes for application-level transparency, and uses anomaly detection to selectively store relevant profiling information. Profiling information is correlated with distributed traces to provide contextual information for root-cause analysis. Protractor has support for different profilers, and experimental work shows impact on end-to-end request latency is less than 3%. The utility of Protractor is further substantiated with a survey showing the majority of the participants would use it frequently / Storskaliga Internettjänster implementeras allt oftare som distribuerade system för att uppnå feltolerans, tillgänglighet och skalbarhet. När en request spänner över flera tjänster ger inte längre end-to-end övervakning en tydlig bild av orsaken till felet. Distribuerad tracing utvecklades för att spåra end-to-end request latency per tjänst och för att ge en indikation vart problemet kan ligger med visar oftas inte orsaken. Genom user research fann vi att root-cause-analys av prestandaproblem ofta fortfarande görs genom att manuellt korrelera information från loggar, stack traces och övervakningsverktyg. Kod-profilering tillhandahåller detaljerad information, men vi fann att den sällan används i produktionssystem på grund av att de kräver ändringar i den befintliga koden, de stora lagringskraven som de introducerar och eftersom det är svårt att korrelera profilerings data med information från andra källor. Utbredning av moderna kodprofilerare med låg overhead öppnar upp möjligheten att kontinuerligt köra dem i produktionsmiljöer. Vi introducerar Protractor som kombinerar kodprofilering och distribuerad tracing. Genom att utnyttja och bygga på koncept så som service meshes uppnår vi transparens på applikationsnivå och använder anomalitetsdetektering för att selektivt lagra relevant profileringsinformation. Den informationen korreleras med distribuerade traces för att ge kontext för root-cause-analys. Protractor har stöd för olika kodprofilerare och experiment har visat att påverkan på end-to-end request latency är mindre än 3Användbarheten av Protractor är ytterligare underbyggd med en undersökning som visar att majoriteten av deltagarna skulle använda den ofta.

The interaction of light in our world is immensely complex, but with mod- ern computers and advanced rendering algorithms, we are beginning to reach the point where photo-realistic renders are truly difficult to separate from real photographs. Achieving realistic or believable global illumination in scenes with participating media is exponentially more expensive compared to our traditional polygonal methods. Light interacts with the particles of a volume, creating com- plex radiance patterns. In this thesis, we introduce an extension to the commonly used point-based color bleeding (PCB) technique, implementing volume scatter contributions. With the addition of this PCB algorithm extension, we are able to render fast, be- lievable in- and out-scattering while building on existing data structures and paradigms. The proposed method achieves results comparable to that of existing Monte Carlo integration methods, obtaining render speeds between 10 and 36 times faster while keeping memory overhead under 5%.

Traditional global illumination lighting techniques like Radiosity and Monte Carlo sampling are computationally expensive. This has prompted the development of the Point-Based Color Bleeding (PBCB) algorithm by Pixar in order to approximate complex indirect illumination while meeting the demands of movie production; namely, reduced memory usage, surface shading independent run time, and faster renders than the aforementioned lighting techniques. The PBCB algorithm works by discretizing a scene’s directly illuminated geometry into a point cloud (surfel) representation. When computing the indirect illumination at a point, the surfels are rasterized onto cube faces surrounding that point, and the constituent pixels are combined into the final, approximate, indirect lighting value. In this thesis we present a performance enhancement to the Point-Based Color Bleeding algorithm through hardware acceleration; our contribution incorporates GPU-accelerated rasterization into the cube-face raster phase. The goal is to leverage the powerful rasterization capabilities of modern graphics processors in order to speed up the PBCB algorithm over standard software rasterization. Additionally, we contribute a preprocess that generates triangular surfels that are suited for fast rasterization by the GPU, and show that new heterogeneous architecture chips (e.g. Sandy Bridge from Intel) simplify the code required to leverage the power of the GPU. Our algorithm reproduces the output of the traditional Monte Carlo technique with a speedup of 41.65x, and additionally achieves a 3.12x speedup over software-rasterized PBCB.

Currently, the CubeSat spacecraft is predominantly used for missions at Low- Earth Orbit (LEO). There are various limitations to expanding past that range, one of the major ones being the lack of sufficient radiation shielding on the Poly-Picosatellite Orbital Deployer (P-POD). The P-POD attaches to a launch vehicle transporting a primary spacecraft and takes the CubeSats out into their orbit. As the demand for interplanetary exploration grows, there is an equal increase in interest in sending CubeSats further out past their current regime. In a collaboration with NASA’s Jet Propulsion Laboratory (JPL), students from the Cal Poly CubeSat program worked on a preliminary design of an interplanetary CubeSat deployer, the Poly-Picosatellite Deep Space Deployer (PDSD). Radiation concerns were mitigated in a very basic manner, by simply increasing the thickness of the deployer wall panels. While this provided a preliminary idea for improved radiation shielding, full analysis was not conducted to determine what changes to the current P-POD are necessary to make it sufficiently radiation hardened for interplanetary travel. This thesis develops a tool that can be used to further analyze the radiation environment concerns that come up with interplanetary travel. This tool is the connection between any geometry modeled in CAD software and the radiation tool OLTARIS (On- Page iv Line Tool for the Assessment of Radiation In Space). It reads in the CAD file and converts it into MATLAB, at which point it can then perform ray-tracing analysis to get a thickness distribution at any user-defined target points. This thickness distribution file is uploaded to OLTARIS for radiation analysis of the user geometry. To demonstrate the effectiveness of the tool, the radiation environment that a CubeSat sees inside of the current P-POD is characterized to create a radiation map that CubeSat developers can use to better design their satellites. Cases were run to determine the radiation in a low altitude orbit compared to a high altitude orbit, as well as a Europa mission. For the LEO trajectory, doses were seen at levels of 102 mGy, while the GEO trajectory showed results at one order of magnitude lower. Electronics inside the P-POD can survive these doses with the current design, confirming that Earth orbits are safe for CubeSats. The Europa- Jovian Tour mission showed results on a higher scale of 107 mGy, which is too high for electronics in the P-POD. Additional cases at double the original thickness and 100 times the original thickness resulted in dose levels at orders of about 107 and 104 mGy respectively. This gives a scale to work off for a “worst case” scenario and provides a path forward to modifying the shielding on deployers for interplanetary missions. Further analysis is required since increasing the existing P-POD thickness by 100 times is unfeasible from both size and mass perspectives. Ultimately, the end result is that the current P-POD standard does not work too far outside of Earth orbits. Radiation-based changes in the design, materials, and overall shielding of the P- POD need to be made before CubeSats can feasibly perform interplanetary missions.

Ray tracing is a graphical technique that provides realistic simulation of light sources and complex lighting effects within three-dimensional scenes, but it is a time-consuming process that requires a tremendous amount of compute power. In order to reduce the number of calculations required to render an image, many different algorithms and techniques have been developed. One such development is the use of tree-like data structures to partition space for quick traversal when finding intersection points between rays and primitives. Even with this technique, ray-primitive intersection for large datasets is still the bottleneck for ray tracing. This thesis proposes the use of a specific spatial data structure, the K-D tree, for faster ray casting of primary rays and enables a ray-triangle culling technique that compliments view frustum and backface culling. The proposed method traverses the entire tree structure to mark nodes to be inactive if it is outside of the view frustum and skipped if the triangle is a backface. In addition, a ray frustum is calculated to test the spatial coherency of the primary ray. The combination of these optimizations reduces the average number of intersection tests per ray from 98% to 99%, depending on the data size.

Ray tracing is a popular technique used in movies and video games to create compelling visuals. Ray traced computer images are increasingly becoming more realistic and almost indistinguishable from real-word images. Due to the complexity of scenes and the desire for high resolution images, ray tracing can become very expensive in terms of computation and memory. To address these concerns, researchers have examined data structures to efficiently store geometric and material information. Sparse voxel octrees (SVOs) and directed acyclic graphs (DAGs) have proven to be successful geometric data structures for reducing memory requirements. Moxel DAGs connect material properties to these geometric data structures, but experience limitations related to memory, build times, and render times. This thesis examines the efficacy of connecting an alternative material data structure to existing geometric representations. The contributions of this thesis include the creation of a new material representation using hashing to accompany DAGs, a method to calculate surface normals using neighboring voxel data, and a demonstration and validation that DAGs can be used to super sample based on proximity. This thesis also validates the visual acuity from these methods via a user survey comparing different output images. In comparison to the Moxel DAG implementation, this work increases render time, but reduces build times and memory, and improves the visual quality of output images.

At the same time as the European Union’s (EU) influence has grown, path-breaking changes in Sweden’s social policy characteristics have appeared. Previous research gives contradictory evidence on whether and how these developments relate, and it remains unknown to what extent the EU contributed to the changes observed in Sweden.  By operationalising four theories on the mechanisms of social policy change (institutionalism, power resources approach, new politics, and new social risks), using the EU as a driving force, and two diverging policy developments as outcomes, this thesis cast the net wider than previous research and applies process tracing methods to a selection of 339 policy documents to answer: (i) How has Europeanisation affected unemployment policy and family policy in Sweden, 1990- 2019? (ii) To what extent can Europeanisation sufficiently explain the retrenchment in unemployment policy while family policies were expanded in the same period of time?  I find no support for the mechanisms of institutionalism and new politics, limited support for new social risk, and mixed support for the power resource approach explaining the Europeanisation of Swedish social policy. Although I found empirical support for parts of several, I conclude that no theory can sufficiently explain the complete causal chain of how the EU influence the two Swedish policy outcomes.