36,195 research outputs found
Automatic Safety mechanisms implementation in Software Model-Based Development
International audienceModel Based Development (MBD) is now a common approach for the automotive industry. Using modeling tools to simulate the behavior of a system before developing the corresponding product(s) through automatic code generation has proven its efficiency. The Road vehicles — Functional safety — ISO 26262 standard (Part6 ) [2] identifies MBD as a recommended approach especially for software architecture design with semi-formal notation and software verification with back-to-back testing through Model in the Loop (MIL) , Software in the Loop (SIL) and Processor in the Loop (PIL). Regarding error detection the standard recommends a certain number of monitoring methods such as “Range checks of input and output data”, “Plausibility check”, “Control flow monitoring”, but does not give any concrete recommendation for software implementation of those methods and therefore how to test through fault injection. In the MBD approach, since code is generated automatically, safety mechanisms must be introduced at model level
Development and Validation of Functional Model of a Cruise Control System
Modern automobiles can be considered as a collection of many subsystems
working with each other to realize safe transportation of the occupants.
Innovative technologies that make transportation easier are increasingly
incorporated into the automobile in the form of functionalities. These new
functionalities in turn increase the complexity of the system framework present
and traceability is lost or becomes very tricky in the process. This hugely
impacts the development phase of an automobile, in which, the safety and
reliability of the automobile design should be ensured. Hence, there is a need
to ensure operational safety of the vehicles while adding new functionalities
to the vehicle. To address this issue, functional models of such systems are
created and analysed. The main purpose of developing a functional model is to
improve the traceability and reusability of a system which reduces development
time and cost. Operational safety of the system is ensured by analysing the
system with respect to random and systematic failures and including safety
mechanism to prevent such failures. This paper discusses the development and
validation of a functional model of a conventional cruise control system in a
passenger vehicle based on the ISO 26262 Road Vehicles - Functional Safety
standard. A methodology for creating functional architectures and an
architecture of a cruise control system developed using the methodology are
presented.Comment: In Proceedings FESCA 2016, arXiv:1603.0837
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Frio pilot in CO2 sequestration in brine-bearing sandstones: The University of Texas at Austin, Bureau of Economic Geology, report to the Texas Commission on Environmental Quality to accompany a class V application for an experimental technology pilot injection well.
GEOSEQ project (LBNL, LLNL, ORNL), NETL, Schlumberger–Doll Research Center, Transpetco, Sandia TechnologiesJackson School of Geoscience
Seismic Response to Injection Well Stimulation in a High-Temperature, High-Permeability Reservoir
Fluid injection into the Earth's crust can induce seismic events that cause damage to local infrastructure but also offer valuable insight into seismogenesis. The factors that influence the magnitude, location, and number of induced events remain poorly understood but include injection flow rate and pressure as well as reservoir temperature and permeability. The relationship between injection parameters and injection-induced seismicity in high-temperature, high-permeability reservoirs has not been extensively studied. Here we focus on the Ngatamariki geothermal field in the central Taupō Volcanic Zone, New Zealand, where three stimulation/injection tests have occurred since 2012. We present a catalog of seismicity from 2012 to 2015 created using a matched-filter detection technique. We analyze the stress state in the reservoir during the injection tests from first motion-derived focal mechanisms, yielding an average direction of maximum horizontal compressive stress (SHmax) consistent with the regional NE-SW trend. However, there is significant variation in the direction of maximum compressive stress (σ1), which may reflect geological differences between wells. We use the ratio of injection flow rate to overpressure, referred to as injectivity index, as a proxy for near-well permeability and compare changes in injectivity index to spatiotemporal characteristics of seismicity accompanying each test. Observed increases in injectivity index are generally poorly correlated with seismicity, suggesting that the locations of microearthquakes are not coincident with the zone of stimulation (i.e., increased permeability). Our findings augment a growing body of work suggesting that aseismic opening or slip, rather than seismic shear, is the active process driving well stimulation in many environments
The application of Bayesian change point detection in UAV fuel systems
AbstractA significant amount of research has been undertaken in statistics to develop and implement various change point detection techniques for different industrial applications. One of the successful change point detection techniques is Bayesian approach because of its strength to cope with uncertainties in the recorded data. The Bayesian Change Point (BCP) detection technique has the ability to overcome the uncertainty in estimating the number and location of change point due to its probabilistic theory. In this paper we implement the BCP detection technique to a laboratory based fuel rig system to detect the change in the pre-valve pressure signal due to a failure in the valve. The laboratory test-bed represents a Unmanned Aerial Vehicle (UAV) fuel system and its associated electrical power supply, control system and sensing capabilities. It is specifically designed in order to replicate a number of component degradation faults with high accuracy and repeatability so that it can produce benchmark datasets to demonstrate and assess the efficiency of the BCP algorithm. Simulation shows satisfactory results of implementing the proposed BCP approach. However, the computational complexity, and the high sensitivity due to the prior distribution on the number and location of the change points are the main disadvantages of the BCP approac
Sensornet checkpointing: enabling repeatability in testbeds and realism in simulations
When developing sensor network applications, the shift from
simulation to testbed causes application failures, resulting in additional
time-consuming iterations between simulation and testbed. We propose
transferring sensor network checkpoints between simulation and testbed
to reduce the gap between simulation and testbed. Sensornet checkpointing
combines the best of both simulation and testbeds: the nonintrusiveness
and repeatability of simulation, and the realism of testbeds
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