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Technical Paper

Application of Model Fuels to Engine Simulation

2007-07-23
2007-01-1843
To address the growing need for detailed chemistry in engine simulations, new software tools and validated data sets are being developed under an industry-funded consortium involving members from the automotive and fuels industry. The results described here include systematic comparison and validation of detailed chemistry models using a wide range of fundamental experimental data, and the development of software tools that support the use of detailed mechanisms in engineering simulations. Such tools include the automated reduction of reaction mechanisms for targeted simulation conditions. Selected results are presented and discussed.
Technical Paper

Thermal Stability Analysis in the Frequency Domain using the ESATAN Thermal Suite

2008-06-29
2008-01-2078
An increasing number of spacecraft missions have very stringent requirements for thermal stability to avoid thermally driven noise from affecting the main observables. For example, it may be necessary to reduce temperature fluctuations in the neighbourhood of the instrument below micro-Kelvin (μK). Consequently, the influence of fluctuations in boundary temperature or internal power dissipation on temperature at the instrument detector must be precisely evaluated. Thermal stability requirements are usually expressed as an upper limit on the linear spectrum density (LSD) of temperature fluctuations. This indicates the strength of the response to a perturbation of a given frequency, and is usually stated in units of K/√Hz. The LSD can be estimated by running a succession of transient simulations and applying Fast Fourier Transforms techniques, but this method is time-consuming and has numerical limitations.
Technical Paper

Improving Subjective Assessment of Vehicle Dynamics Evaluations by means of Computer-Tablets as Digital Aid

2016-04-05
2016-01-1629
Vehicle dynamics development relies on subjective assessments (SA), which is a resource-intensive procedure requiring both expert drivers and vehicles. Furthermore, development projects becoming shorter and more complex, and increasing demands on quality require higher efficiency. Most research in this area has focused on moving from physical to virtual testing. However, SA remains the central method. Less attention has been given to provide better tools for the SA process itself. One promising approach is to introduce computer-tablets to aid data collection, which has proven to be useful in medical studies. Simple software solutions can eliminate the need to transcribe data and generate more flexible and better maintainable questionnaires. Tablets’ technical features envision promising enhancements of SA, which also enable better correlations to objective metrics, a requirement to improve CAE evaluations.
Technical Paper

Incremental Modeling and Validation of Space Mission Using AADLv2

2011-10-18
2011-01-2529
The development process of space mission software has to go through numerous steps, from early dimensioning factors at system level (e.g. energy to be consumed by a system, weight of equipment) to the description of low-level software concerns (tasks period, etc.). Most of the time, mission components are taken or derived from existing projects and use well-known best practices: hardware and software concerns are designed from a set of existing components, and are usually well tested and documented. However, teams, with different technical backgrounds, and development approaches, achieve the design. This adds incidental complexity to the design of a common architecture and its verification. Consequently, even if design of new systems is close to existing ones, the recurring key challenge is to reconcile the different views built by these teams, and to ensure that all properties are preserved and validated.
Technical Paper

Esarad--Improvements to the European Space AgencyS Radiative Analyses

1996-07-01
961374
ESARAD is an integrated suite of analysis tools for thermal radiative analysis. The suite provides modules for: • Geometry Definition; • Calculation of view factor, radiative exchange factor and solar, albedo and planet flux results; •Visualization of models in orbit with pre- and post-processing of radiative and thermal results; • Reporting of all aspects of the model; and • Generation of Input Files for Thermal Analysis tools. ESARAD is driven by a fully developed GUI, providing the user with a simple, intuitive windows, menus, forms interface to all its features. A modern, block structured language can also be used to run ESARAD. This gives the advanced user great power and flexibility to perform the most complex analyses. ESARAD was designed and developed between 1988 and 1991 to replace the VWHEAT software used by ESA at that time.
Technical Paper

Development of Columbus Orbital Facility Thermal Mathematical Models for Integrated International Space Station Thermal Analyses

1996-07-01
961540
The Columbus Orbital Facility is being developed as the European laboratory contribution to the United States' led International Space Station programme. The need to exchange thermal mathematical models frequently amongst the Space Station partners for thermal analyses in support of their individual programme milestone, integration and verification activities requires the development of a commonly agreed and effective approach to identify and validate mathematical models and environments. The approach needs to take into account the fact that the partners have different model and software tool requirements and the fact that the models need to be properly tailored to include all the relevant design features. It must also decouple both programmes from the unavoidable design changes they are still undergoing. This problem presents itself for both active and passive thermal interfaces.
Technical Paper

Optimization-Based Robust Architecture Design for Autonomous Driving System

2019-04-02
2019-01-0473
With the recent advancement in sensing and controller technologies architecture design of an autonomous driving system becomes an important issue. Researchers have been developing different sensors and data processing technologies to solve the issues associated with fast processing, diverse weather, reliability, long distance recognition performance, etc. Necessary considerations of diverse traffic situations and safety factors of autonomous driving have also increased the complexity of embedded software as well as architecture of autonomous driving. In these circumstances, there are almost countless numbers of possible architecture designs. However, these design considerations have significant impacts on cost, controllability, and system reliability. Thus, it is crucial for the designers to make a challenging and critical design decision under several uncertainties during the conceptual design phase.
Technical Paper

New Safety Technologies for the Automotive Industry

2006-10-16
2006-21-0065
With the increasing complexity of automotive systems and the related increasing use of software in them, new approaches are needed to ensure safety. In these new types of automotive systems, safety and reliability are different and require different engineering approaches. Accidents are increasingly due to design errors and to dysfunctional interactions among components rather than component failure. In addition, safety must be engineered and built into the design from the beginning; it is not possible to effectively and affordably add safety devices onto a finished design. This paper describes the need for new approaches to automotive safety and describes an alternative to the traditional reliability-based approaches to safety engineering. The new approach is based on systems theory and views accidents in terms of lack of control or enforcement of the behavioral constraints required to ensure safety.
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