• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 27
  • 8
  • 2
  • 1
  • 1
  • Tagged with
  • 43
  • 43
  • 11
  • 10
  • 8
  • 8
  • 8
  • 8
  • 8
  • 8
  • 7
  • 7
  • 7
  • 7
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Situational awareness and interactive system safety analysis

Sandom, Carl William January 2000 (has links)
No description available.
2

Development of a Collision Avoidance Truck System from a Functional Safety Perspective

Ortman, Victor, Gradin, Petter January 2011 (has links)
ISO 26262 is a functional safety standard under development at the time of this thesis. It is an adaptation of the functional safety standard IEC 61508, aimed at development of automotive electrical/electronic systems. The version of ISO-26262 that was used and discussed in this thesis is the final draft released in January 2011. In this thesis, a subset of ISO-26262 is applied in the development of a safety critical driver assistance system for a Scania vehicle. The parts of ISO-26262 that are treated are Part 3: Concept phase, Part 4: Product development at the system level and Part 5: Product development at the hardware level. Throughout the thesis we evaluate ISO-26262 and report our experience of working with it. The driver assistance system under development, which ISO-26262 is applied to, is Collision Avoidance by Steering, a system that aims to avoid or mitigate rear-end collisions with vehicles in front by automatic steering of the vehicle.
3

Probabilistic Safety Assessment using Quantitative Analysis Techniques : Application in the Heavy Automotive Industry

Björkman, Peter January 2011 (has links)
Safety is considered as one of the most important areas in future research and development within the automotive industry. New functionality, such as driver support and active/passive safety systems are examples where development mainly focuses on safety. At the same time, the trend is towards more complex systems, increased software dependence and an increasing amount of sensors and actuators, resulting in a higher risk associated with software and hardware failures. In the area of functional safety, standards such as ISO 26262 assess safety mainly focusing on qualitative assessment techniques, whereas usage of quantitative techniques is a growing area in academic research. This thesis considers the field functional safety, with the emphasis on how hardware and software failure probabilities can be used to quantitatively assess safety of a system/function. More specifically, this thesis presents a method for quantitative safety assessment using Bayesian networks for probabilistic modeling. Since the safety standard ISO 26262 is becoming common in the automotive industry, the developed method is adjusted to use information gathered when implementing this standard. Continuing the discussion about safety, a method for modeling faults and failures using Markov models is presented. These models connect to the previous developed Bayesian network and complete the quantitative safety assessment. Furthermore, the potential for implementing the discussed models in the Modelica language is investigated, aiming to find out if models such as these could be useful in practice to simplify design work, in order to meet future safety goals.
4

Functional Safety Assessment in Autonomous Vehicles

Shastry, Akshay Kumar 07 June 2018 (has links)
Autonomous vehicles (AVs) are a class of safety-critical systems that are capable of decision-making and operate with little or no human intervention. For such complex systems designed to function in diverse operational domains such as rain, snow, freeway, urban roads, etc., system safety is paramount. Management of the system's safety throughout its life-cycle, from the conceptualization stage to the end of the lifecycle, is of primary importance. We describe a revision of functional safety standard ISO 26262 to support autonomous vehicles and the underlying electronic/electrical control architecture. There is a need to modify the Automotive Safety Integrity Levels (ASILs) defined in the ISO 26262 as "Controllability", a factor in determining an ASIL, is no longer applicable; the driver is no longer in a position to control the vehicle. The vehicle has taken over the responsibility of evaluating the environment and determines its next course of action to complete its current mission. These decisions have a tremendous impact on the overall safety of the system during a hazardous event and can be the difference between a successful journey and a traffic incident. To better enable the designers of such systems, we introduce a new method to assess the functional safety and derive safety goals, which are the top level safety requirement. We present a new metric-Risk Mitigation Factor to assess the decision making capability of the vehicle and to replace controllability in the ASIL definition. The case study presented highlights the advantages of using the introduced metric in defining safety goals for the autonomous vehicle. / Master of Science
5

Model-Based Fault Diagnosis For Automotive Functional Safety

Zhang, Jiyu January 2016 (has links)
No description available.
6

Performance of an electro-hydraulic active steering system

Fischer, Eric, Sitte, André, Weber, Jürgen, Bergmann, Erhard, de la Motte, Markus 27 April 2016 (has links) (PDF)
Hydrostatic steering systems are used in construction and agricultural machines alike. Because of their high power density, hydraulic drives are qualified for the use in vehicles with high steering loads. Conventional hydrostatic steering systems are limited in terms of steering comfort and driver assistance. For realisation of appropriate steering functions, electro-hydraulic solutions are necessary. This paper provides an overview on existing implementations and introduces a novel steering system. The presented active steering system with independent meter-in and meter-out valves fills the gap between existing active steering systems and steer-by-wire solutions. An appropriate control and safety concept provides advanced steering functions for on-road usage without the fully redundant structure of steer-by-wire systems.
7

STATISTICAL METHODS FOR CRITICAL PATHS SELECTION AND FAULT COVERAGE IN INTEGRATED CIRCUITS

Javvaji, Pavan Kumar 01 May 2019 (has links)
With advances in technology, modern integrated circuits have higher complexities and reduced transistor sizing. In deep sub-micron, the parameter variation-control is difficult and component delays vary from one manufactured chip to another. Therefore, the delays are not discrete values but are a statistical quantity, and statistical evaluation methods have gained traction. Furthermore, fault injection based gate-level fault coverage is non-scalable and statistical estimation methods are preferred. This dissertation focuses on scalable statistical methods to select critical paths in the presence of process variations, and to improve the defect coverage for complex integrated circuits. In particular, we investigate the sensitization probability of a path by a test pattern under statistical delays. Next, we investigate test pattern generation for improving the sensitization probability of a path, selecting critical paths that yield high defect coverage, and scalable method to estimate fault coverage of complex designs using machine learning techniques.
8

Development of an ISO 26262 ASIL D compliant verification system

Carlsson, Daniel January 2013 (has links)
In 2011 a new functional safety standard for electronic and electrical systems in vehicles waspublished, called ISO 26262. This standard concerns the whole lifecycle of the safety criticalelements used in cars, including the development process of such elements. As the correctnessof the tools used when developing such an element is critical to the safety of the element,the standard includes requirements concerning the software tools used in the development,including verification tools. These requirements mainly specify that a developer of a safetycritical element should provide proof of their confidence in the software tools they are using.One recommended way to gain this confidence is to use tools developed in accordance to a“relevant subset of [ISO 26262]”.This project aims to develop a verification system in accordance to ISO 26262, exploringhow and what specifications should be included in this “relevant subset” of ISO 26262 andto which extent these can be included in their current form. The work concludes with thedevelopment of a single safety element of the verification system, to give an demonstrationof the viability of such a system.
9

Framework for Optimally Constrained Autonomous Driving Systems

Repisky, Philip Vaclav 30 November 2020 (has links)
The development of Automated Driving Systems (ADS) has been ongoing for decades in varying levels of sophistication. Levels of automation are defined by Society of American Engineers (SAE) as 0 through 5, with 0 being full human control and 5 being full automation control. Another way to describe levels of automation is through concepts of Functional Safety (FuSa) and Operational Safety (OpSa). These terms of FuSa and OpSa are important, because ADS testing relies on both. Current recommendations for ADS testing include both OpSa and FuSa requirements. However, an examination of ADS safety requirements (e.g., industry reports, post-crash analysis reports, etc.) reveals that ADS safety arguments, in practice, depend almost completely on well-trained human operators, referred to in the industry as in vehicle fallback test drivers (IFTD). To date, the industry has never fielded a truly SAE L4 ADS on public roads due to this persistent hurdle of needing a human operator for Operational Safety. There is a tendency in ADS testing to reference International Standards Organization (ISOs) for validated vehicles for vehicles that are still in development (i.e., unvalidated). To be clear, ISOs for ADS end products are not necessarily applicable to ADS in development. With this in mind, there is a clear gap in the industry for unvalidated ADS literature. Because of this gap, ADS testing for unvalidated vehicles often relies on safety requirements for validated vehicles. This issue remains a significant challenge for ADS testing. Recognizing this gap in on-road, in-development vehicle safety, there is a need for the ADS industry to develop a clear strategy for transitioning from an IFTD (Operational Safety) to an ADS (Functional Safety). Therefore, the purpose of this thesis is to present a framework for transitioning from Operational Safety to Functional Safety. The framework makes this possible through an inductive analysis of available definitions of onroad safety to arrive at a definition that leverages Functional and Operational Safety along a continuum. Ultimately, the framework aims to contribute to onroad safety testing for the ADS industry. / Master of Science / The development of Self-Driving Cars has been ongoing for decades in varying levels of sophistication. Levels of automation are defined by Society of American Engineers (SAE) as 0 through 5, with 0 being full human control and 5 being full automation control. Another way to describe levels of automation is through concepts of Robotic Control and Human Control. If a vehicle relies completely on Human Control, a human operator is responsible for all on-road safety. On the other hand, a fully autonomous would be considered fully in Robotic Control. These terms of Robotic Control and Human Control are important, because Self-Driving Car testing relies on both. Current recommendations for Self-Driving Car testing include both Robotic Control and Human Control requirements. However, an examination of Self-Driving Cars documentation (e.g., industry reports, post-crash analysis reports, etc.) reveals that Self-Driving Car safety arguments, in practice, depend almost completely on well-trained human operators. To date, the industry has never fielded a truly SAE L4 Self-Driving Car on public roads due to this persistent hurdle of needing a human operator for Human Control. There is a tendency in Self-Driving Car testing to reference standars for validated vehicles for vehicles that are still in development (i.e., unvalidated). To be clear, standards for Self-Driving Car end products are not necessarily applicable to Self-Driving Cars in development. With this in mind, there is a clear gap in the industry for unvalidated Self-Driving Car literature. Because of this gap, Self-Driving Car testing for unvalidated vehicles often relies on documentation for validated vehicles. This issue remains a significant challenge for Self-Driving Car testing. Recognizing this gap in on-road, in-development vehicle safety, there is a need for the Self-Driving industry to develop a clear strategy for transitioning from Human Control to Robot Control. Therefore, the purpose of this thesis is to present a framework for transitioning from Human to Robot Control. The framework makes this possible through an inductive analysis of available definitions of onroad safety to arrive at a definition that leverages all definitions of Safety along a continuum. Ultimately, the framework aims to contribute to onroad safety testing for the Self-Driving industry.
10

Využití bezpečnostního PLC pro řízení plynových hořáků / Use of a safety PLC for gas burners

Petr, Vojtěch January 2016 (has links)
The topic of this diploma thesis is the safety of a gas burner control. The aim is to fully automate the system by using a gas burner safety control system (Fail-Safe PLC) so as to reduce to minimum the risks. Because great emphasis is placed on safety, so Czech standards and what is connected with safety control systems are discussed. This project is implemented in cooperation with industrial automation company ElektroMAR a. s.

Page generated in 0.0979 seconds