Procedural Phasor Noise

International audienceProcedural pattern synthesis is a fundamental tool of Computer Graphics, ubiquitous in games and special effects. By calling a single procedure in every pixel – or voxel – large quantities of details are generated at low cost, enhancing textures, producing complex structures within and along surfaces. Such procedures are typically implemented as pixel shaders. We propose a novel procedural pattern synthesis technique that exhibits desirable properties for modeling highly contrasted patterns, that are especially well suited to produce surface and microstructure details. In particular, our synthesizer affords for a precise control over the profile, orientation and distribution of the produced stochastic patterns, while allowing to grade all these parameters spatially. Our technique defines a stochastic smooth phase field – a phasor noise –that is then fed into a periodic function (e.g. a sine wave), producing an oscillating field with prescribed main frequencies and preserved contrast oscillations. In addition, the profile of each oscillation is directly controllable (e.g. sine wave, sawtooth, rectangular or any 1D profile). Our technique builds upon a reformulation of Gabor noise in terms of a phasor field that affords for a clear separation between local intensity and phase. Applications range from texturing to modeling surface displacements, as well as multi-material microstructures in the context of additive manufacturing

Designing sound : procedural audio research based on the book by Andy Farnell

In procedural media, data normally acquired by measuring something, commonly described as sampling, is replaced by a set of computational rules (procedure) that defines the typical structure and/or behaviour of that thing. Here, a general approach to sound as a definable process, rather than a recording, is developed. By analysis of their physical and perceptual qualities, natural objects or processes that produce sound are modelled by digital Sounding Objects for use in arts and entertainments. This Thesis discusses different aspects of Procedural Audio introducing several new approaches and solutions to this emerging field of Sound Design.Em Media Procedimental, os dados os dados normalmente adquiridos através da medição de algo habitualmente designado como amostragem, são substituídos por um conjunto de regras computacionais (procedimento) que definem a estrutura típica, ou comportamento, desse elemento. Neste caso é desenvolvida uma abordagem ao som definível como um procedimento em vez de uma gravação. Através da análise das suas características físicas e perceptuais , objetos naturais ou processos que produzem som, são modelados como objetos sonoros digitais para utilização nas Artes e Entretenimento. Nesta Tese são discutidos diferentes aspectos de Áudio Procedimental, sendo introduzidas várias novas abordagens e soluções para o campo emergente do Design Sonoro

A brick in the wall: Staggered orientable infills for additive manufacturing

International audienceAdditive manufacturing is typically conducted in a layer-by-layer fashion. A key step of the process is to define, within each planar layer, the trajectories along which material is deposited to form the final shape. The direction of these trajectories triggers an anisotropy in the fabricated parts, which directly affects their properties, from their mechanical behavior to their appearance. Controlling this anisotropy paves the way to novel applications, from stronger parts to controlled deformations and surface patterning.This work introduces a method to generate trajectories that precisely follow an input direction field while simultaneously avoiding intra- and inter-layer defects. Our method results in spatially coherent trajectories - all follow the specified direction field throughout the layers - while providing precise control over their inter-layer arrangement. This allows us to generate a staggered layout of trajectories across layers, preventing unavoidable tiny gaps from forming tunnel-shaped voids throughout a part volume.Our approach is simple, robust, easy to implement, and scales linearly with the input volume. It builds upon recent results in procedural generation of oscillating patterns, generating a signal in the 3D domain that oscillates with a frequency matching the deposition beads width while following the input direction field. Trajectories are extracted with a process akin to a marching square

Exploration of COTS Ultrasonic NDE Methods for ISS MMOD Impact Analysis

The high orbital speed of the International Space Station (ISS) has created a concern about Micro-Meteorite and Orbital Debris (MMOD). The possibility exists that such an impact could cause significant damage to the ISS pressure wall, and possibly lead to a pressure leak. This paper explores the potential of using commercial off-the-shelf (COTS) Ultrasonic Non-Destructive Evaluation (NDE) techniques in order to inspect and analyze MMOD impact damage if such an event would happen to occur. Different types of intra vehicular activity (IVA) Ultrasonic NDE equipment were evaluated, including the Olympus Omniscan MX and the General Electric Phasor XS. The equipment was tested by inspecting various aluminum standards and impact damage test plates in order to determine technological limitations of the equipment as well as the ease of use and availability of features. This study allowed for the design of scanning procedures in order to evaluate the extent of damage caused by an MMOD impact. Lastly, comparisons were drawn between the different pieces of COTS software and a recommendation is made based on each device s capability

Catch Me If You Can: Using Power Analysis to Identify HPC Activity

Monitoring users on large computing platforms such as high performance computing (HPC) and cloud computing systems is non-trivial. Utilities such as process viewers provide limited insight into what users are running, due to granularity limitation, and other sources of data, such as system call tracing, can impose significant operational overhead. However, despite technical and procedural measures, instances of users abusing valuable HPC resources for personal gains have been documented in the past \cite{hpcbitmine}, and systems that are open to large numbers of loosely-verified users from around the world are at risk of abuse. In this paper, we show how electrical power consumption data from an HPC platform can be used to identify what programs are executed. The intuition is that during execution, programs exhibit various patterns of CPU and memory activity. These patterns are reflected in the power consumption of the system and can be used to identify programs running. We test our approach on an HPC rack at Lawrence Berkeley National Laboratory using a variety of scientific benchmarks. Among other interesting observations, our results show that by monitoring the power consumption of an HPC rack, it is possible to identify if particular programs are running with precision up to and recall of 95\% even in noisy scenarios

PHASOR MEASUREMENT UNIT TESTING AND CHARACTERIZATION

The power grid is a complex system composed of many different elements. Knowledge of electrical waveform content across the grid is key to managing power and maintaining stability. Electrical waveforms can be represented mathematically as time-varying phasors. Electrical phasors give information pertaining to the magnitude of the waveform as well as the phase relationship of the waveform to a reference. A Phasor Measurement Unit (PMU) is a device that is installed at a node on the power grid and measures electrical phasors. The potential of near real time phasor information is powerful and has driven PMU application technology forward at a rapid pace over the last decade. The IEEE C37.118 standard establishes requirement guidelines for PMU performance. Before PMUs are implemented in real time applications researchers may wish to test PMUs to obtain specific device behavior. This thesis will describe the development of a robust PMU test bench that is capable producing dynamic input signals. Dynamic testing and analysis will reveal time domain and frequency domain characteristics of the PMU under test. A discussion on the reported response and the real time response of PMUs will be covered to give more insight into the real time behavior and application of PMUs. Conclusions will take one last look at the project and discuss the potential of this work as a starting point for future PMU testing

Physically informed car engine sound synthesis for virtual and augmented environments

The richness of crossmodal feedback in car driving makes it an engaging, complex, yet “natural” activity. Audition plays an important role, as the engine sound, perceived in the cabin, conveys relevant cues about the vehicle motion. In this paper, we introduce a procedural and physically informed model for synthetic combustion engine sound, as an effective, flexible and computationally efficient alternative to sample-based and analysis/resynthesis approaches. The sound model, currently being developed as Max/MSP external, has been integrated in GeneCars, a driving simulator environment for industrial sound design, and SkAT Studio, a demonstration framework for the rapid creation of audio processing workflows

Locating a Moving Target in a High Clutter Environment

This paper addresses the problem of locating a slowly moving target in a high clutter environment. The test uses a vector network analyzer (VNA) as a radar system. The radar system is operated as a frequency-stepped continuous wave (FSCW) radar. The real and imaginary amplitude values of the S21 parameter are recorded for each frequency step. The inverse-fast Fourier (IFFT) is then applied to the complex S21 data to recover the time domain returns from a room or hallway. The target is located using a variable pulse repetition frequency (PRF) moving target indicator (MTI) filter. A reference pulse of the room or hallway was acquired, initially, with no target present. Consecutive pulses were then measured with the target present in the room or hallway. After each pulse, the target was moved 3 ft and a new measurement was saved. This process was repeated for each target. Targets included a corner reflector, a sphere, and a human subject. The results showed that the variable PRF, single-stage, MTI filter effectively identified the presence of a target in a high clutter environment for all three target cases. Subtracting a reference pulse from the pulses when a target was present in the room or hallway suppressed most of the background clutter. There were some returns from strong reflection points in the room or hallway still appeared in the filter returns, however. This was due to either the target intercepting and scattering the energy that would otherwise reflect from the background or the range cells of the background return signals being moved due to multipath. This test demonstrated that use of a reference pulse in a variable PRF MTI filter allowed the detection of a slowly moving target. Future work will be needed to address the issue of strong reflection points appearing after filtering. Possible solutions include addition of a second MTI stage to the processing.School of Electrical & Computer Engineerin