Spark (mathematics)

About: Spark (mathematics) is a research topic. Over the lifetime, 7304 publications have been published within this topic receiving 63322 citations.

Nonperiodic Oscillations of Pressure in a Spark Ignition Engine

Abstract: We report our results on non-periodic experimental time series of pressure in a spark ignition engine. The experiments were performed for a low rotational velocity of a crankshaft and a relatively large spark advance angle. We show that the combustion process has many chaotic features. Surprisingly, the reconstructed attractor has a characteristic butterfly shape similar to a chaotic attractor of Lorentz type. The suitable recurrence plot shows that the dynamics of the combustion is a nonlinear multidimensional process mediated by stochastic noise.

SparkGA: A Spark Framework for Cost Effective, Fast and Accurate DNA Analysis at Scale

Abstract: In recent years, the cost of NGS (Next Generation Sequencing) technology has dramatically reduced, making it a viable method for diagnosing genetic diseases. The large amount of data generated by NGS technology, usually in the order of hundreds of gigabytes per experiment, have to be analyzed quickly to generate meaningful variant results. The GATK best practices pipeline from the Broad Institute is one of the most popular computational pipelines for DNA analysis. Many components of the GATK pipeline are not very parallelizable though. In this paper, we present a parallel implementation of a DNA analysis pipeline based on the big data Apache Spark framework. This implementation is highly scalable and capable of parallelizing computation by utilizing data-level parallelism as well as load balancing techniques. In order to reduce the analysis cost, the framework can run on nodes with as little memory as 16GB. For whole genome sequencing experiments, we show that the runtime can be reduced to about 1.5 hours on a 20-node cluster with an accuracy of up to 99.9981%. Our solution is about 71% faster than other state-of-the-art solutions while also being more accurate. The source code of the software described in this paper is publicly available at https://github.com/HamidMushtaq/SparkGA1.git.

Model Reduction of Turbocharged (TC) Spark Ignition (SI) Engines

Abstract: This paper proposes a new procedure to reduce the order of control oriented turbocharged (TC) spark ignition (SI) engine models. The starting point of this work is a higher dimensional, fully validated model defined which is not appropriate for control design. The model reduction technique is based on the identification of time scale separation within the dynamics of various engine state variables with pertinent use of perturbation theory. The model reduction is accomplished in two steps and exploits the dynamic and physical characteristics of engine design and operation. In the first step, regular and singular perturbation theories are collectively employed to eliminate temperature dynamics and replace them with their quasi-steady state values. This is followed by the elimination of fast pressures. As a result, a library of engine models is obtained which are associated with each other on a sound theoretical basis and at the same time allow sufficient flexibility in terms of the reduced order modeling. Different assumptions under which this model reduction is justified are presented and their implications are discussed. The approximating properties of the proposed engine models with respect to the original higher dimensional model are quantitatively assessed through comprehensive simulations.

High efficiency, extended life spark plug having shaped firing tips

Abstract: A spark plug is provided which is suitable for use in a spark ignition system for an internal combustion engine. The spark plug is equipped with a specially configured firing tip on each of its electrodes for the purpose of minimizing the demand voltage of the spark plug, as well as extending the life of the spark plug by maximizing the time over which the demand voltage will remain within an acceptable level. For this purpose, the firing tips are configured such that their firing surfaces include at least three edges and three corners which serve as arc initiation sites of a relatively low resistance arc path between the electrodes.

SPARK: a framework for multi-scale agent-based biomedical modeling

Abstract: Multi-scale modeling of complex biological systems remains a central challenge in the systems biology community. A method of dynamic knowledge representation known as agent-based modeling enables the study of higher level behavior emerging from discrete events performed by individual components.In this work, we describe SPARK (Simple Platform for Agent-based Representation of Knowledge), a framework for agent-based modeling specifically designed for systems-level biomedical model development. SPARK is a standalone application written in Java. It provides a user-friendly interface, and a simple programming language for developing Agent-Based Models (ABMs). SPARK has the following features specialized for modeling biomedical systems: 1) continuous space that can simulate real physical space; 2) flexible agent size and shape that can represent the relative proportions of various cell types; 3) multiple spaces that can concurrently simulate and visualize multiple scales in biomedical models; 4) a convenient graphical user interface. Existing ABMs of diabetic foot ulcers and acute inflammation were implemented in SPARK. Models of identical complexity were run in both NetLogo and SPARK; the SPARK-based models ran two to three times faster.We are currently utilizing SPARK to develop multi-scale inflammation models in diverse settings such as cancer, viral infection, and spinal cord injury.