Safety concepts defined

This Chapter starts with an example of an actual accident, that occurred in spite of all the measures and indicators implemented to prevent it from happening. Subsequently, some important safety concepts are defined to prevent confusion and misinterpretations. Then it is discussed why in spite of the developments in safety scope and environment since the industrial revolution measuring safety is still a problem. The Chapter ends by presenting the research scope and the derived research questions. 

A logic diagram that spans the entire realm of fire safety measures. It is defined in National Fire Protection Association (NFPA) 550, Guide to the Fire Safety Concepts Tree, which describes its structure, application, and limitations. 

Casey Hooke, advanced practice nurse and creator of the Safety Action Team (SAT) concept, defines SATs as department- or unit-based interdisciplinary work groups that provide a "think tank" for staff to identify safety concerns, process them, and brainstorm new ways to address them (Hooke, 2002). Group membership varies according to individual needs, but SATs strive to include members who represent the continuum of care for the patients they serve. SATs include registered nurses, physicians, pharmacists, respiratory care practitioners, child-life specialists, unit service coordinators, and members of the management team. The group is chaired by a staff leader, or sometimes by two staff leaders who share the responsibility. 

ISO 26262 is based on the system architecture. The vehicle itself consists of different systems their electric and electronic architecture is modeled in the according development process. The design and development of the EEA of a vehicle is based on the work products from preceding development phases like the design of a broadly defined system architecture concept. In the future it has to consider the results of analysis, considerations and classification of safety aspects, demanded by ISO 26262. The electric and electronic (EE) part of the system architecture is iteratively refined and detailed during the development process. The impact of ISO 26262 to the modeling of the EEA and the contribution of the EEA modeling towards the fulfillment of the overall safety concept is discussed in this paper. 

This definition can be used to identify inconsistencies in early phases of the design. In case an MTBF specification is inconsistent, an engineer may decide to plan for a redimdant implementation of a component to increase its overall MTBF value. This can be specified in the PBS by the pattern defined in Table 5. The pattern only provides a very simple mean to express some safety concept and is only suitable for the early stages of the design. Refinements of such specifications may be done by using more elaborated concepts like safety patterns [10). 

As a next step, the Safety Concept is derived. It is defined as the specification of the safety requirements, their allocation to system elements and their interaction necessary to achieve safety goals [4]. The construction of the safety concept is a generic step which is compliant to all considered safety standards. However, the necessary content of the safety concept may differ from domain to domain. 

Safety in water supply is defined as a state of water management that enables to cover the current and future water demand, in a technically and economically justified way, by the requirements of environmental protection (Berg et al. 2010, Ezell et al. 2000, Kolowrocki 2001, Li et al. 2009, Mays 1989, Rak 2009, Tchorzewska-Cieslak 2011, Tchorzewska-Cieslak 2011 et al. 2012). The basic and primary entity to which the water safety concept is directed is water consumer. The secondary is water supplier—water manufacturer. That is why... 

Our paper is organized as follows. The goal structuring notation is introduced in Sect. 2.1. In Sect. 2.2, we give a brief overview of ISO 26262. Our method is presented in Sect. 3. This section also describes our UML profile, which is used to express the functional safety concept. Based on this profile, we define the validation conditions. The tool support is outlined in Sect. 4. We introduce the illustrative example of an electronic steering column lock system as case study in Sect. 5. Section 6 presents related work, while Sect. 7 concludes the paper and gives directions for future work. 

After defining all attributes of the functional safety concept, it is automatically checked that for each safe state at least one safety-related function is defined and that for each assumption at least one general safety requirement exists by executing Conditions 3C01SS and 3C02AS (see Tab. 4). 

Which general targets could be formulated for a safety concept. ISO 26262 clearly defined that the functional and technical safety concept should be defined derived from the ITEM Definition, a system on vehicle level and the resulting safety goals from the Hazard and Risk Analysis. 

Two objectives are defined for safety validation the first is the evidence that the safety goals are considered adequately in the context of the functional safety concept and the defined item. The second objective asks for the evidence that the safety goals themselves are correct and achieved on vehicle level. The hope of any safety validation is, to proof that the vehicle is safe as such, hut ISO 26262 could provide support on the evidence of functional safety for E/E-Systems. The safety-live-cycle in ISO 26262, part 2 shows, that external measures and also measures of other technology have to be considered during safety validation. In 9.2 General the relation to other activities are detailed. 

ISO 26262 requires mainly the compiled work-products derived from the safety activities during concept and development phase as planned based of the safety goals and the defined safety concept. Those should provide sufficient evidence for the functional safety of the item. 

The Creation of the Functional and Technical Safety Concept that on the one hand defines solutions how to fulfill the safety goals, on the other hand defines mechanisms to avoid the failures identified by the safety analysis, or to detect them and react on them in an appropriate manner. 

The Safety Concept unites some elements of a requirements specification (the so called Safety Requirements) and of a design specification, as it defines not only what to do, but also how to implement it technically (e.g. by requiring qualified components, by allocating safety-relevant software functions to distinct software partitions, by specifying plausibility checks, by defining redundant implementation is some cases). 

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