Functional events

SELF is a two-stage process going from functional event trees, to system fault trees events pertinent to the accident progression. 

S.4 Small Event Tree-Large Fault Tree SELF Functional Event Trees... 

Function event trees are concerned with depicting functions that must happen to mitigate an initiating event. The headings of the function event tree are statements of safety functions that are required but that may fail in an accident sequence. 

Function event trees are developed to represent the plant s response to each initiator. The function event tree is not an end product it is an intermediate step that provides a baseline of information and permits a stepwise approach to sorting out the complex relationships between potential initiating events and the response of the mitigating features. They structure plant respoases to accident conditions - possibly as time sequences. The transition labels of function event trees (usually along the top of the event tree) are analyzed to provide the probability of that function occurring or not occurring. 

Function event trees include primarily the engineered safety features of the plant, but other systems provide necessary support functions. For example, electric power system failure amid reduce the effectiveness of the RCS heat-removal function after a transient or small UJ( A. Therefore, EP should be included among the systems that perform this safety function. Siipfiort systems such as component-cooling water and electric power do not perform safety functions directly. However, they significantly contribute to the unavailability of a system or group of systems that perform safety functions. It is necessary, therefore, to identify support systems for each frontline ssstcm and include them in the system analysis. 

The problem with function event trees is that some functions are quite complex and must be analyzed. If a function event tree models the plant s response to an accident initiator, modeling system responses in a fault tree will not clearly exhibit the functional criteria. 

A system event tree provides this display and uses the Tech Spec ciiicna (n specify the func tion. Figure 3.4.5-4 shows a system event tree developed from the function event tree presented as Figure 3.4.5-2, It should be noted that the functions RS, COl, C02 and ECR are accomplished by systems and are thus unchanged ongoing from a function to system event tree. ECI is quiic complex and may be performed by various system combinations such as 2 or 1 core spray (CS) loops, or various combinations of low pressure in jection (LPCI),... 

System event trees use the information on the effects of loss of various safety functions identified in the function event trees. However, the sequences in the system event trees are likely to differ somewhat from the function event trees because system faults may fail multiple functions. 

Fig. 3.4.5-2 Large LOCA as a Function Event Tree (adapted from NUREG/CR-2. 00 ...

To unlock its full potential, C-H activation has to be coupled with a functionalization event (e.g., 3—>4). For instance, a hydride elimination occurring after the formation of metal complexes such as 3 furnishes olefins, versatile intermediates for further modification reactions. Transition metal-catalyzed atom- or atom group-transfer reactions that permit the introduction of oxygen-, carbon-, and boron-containing groups are also presented. 

How can the system s inputs be modified to eliminate, reduce or prevent a harmful function, event or condition from impacting the output Or, how can the system s output be modified in a corrective or reactive way ... 

Signaling pathways is a subarea of biological chemistry that is concerned with the study of molecular interactions and/or reactions in sequence in the living system that triggers a functional event. 

Acceleration. As new concepts and developments appear, in and out of the distribution function, events will bear faster on the Distribution Manager. He must accelerate his own managerial processes as well as the physical distribution flow of which he is the steward. 

Data view This view includes the data processing environment as well as the messages triggering functions or being triggered by functions. Events such as customer order received, ... 

I should mention that Kim (1998b) has pointed out that the functional notion of orders is different from the notions of micro- and macrolevels. The latter notion of levels concerns scale functional events and their realizers occur at the same level in that sense of level. 

I will speak of NRP theorists as taking functional properties to be constitutive properties of events. Alternatively, we could say that they take functional properties to be essential properties of events in either Lewis s or Yablo s (1992b) sense of essential properties of events, for Yablo s property exemplification account of events also allows for events with functional essences. By a functional event token, I will henceforth mean a second-order (or higher-order) event token, an event with a functional property as a constitutive property (or an event with a functional essence). Notice that although this role-functionalist view of event tokens does not treat quantification as an object-forming operation, it treats it as a particularforming operation, for events are particulars. 

The NRP theorists in question hold that functional properties can be constitutive properties of events. Indeed, on their view, it is because functional properties can be constitutive properties of events (or event essences) that no functional event token is identical with its physical realization. If this view is correct, then token physicalism is false. This event dualism, however, is compatible with the thesis of supervenience on the physical. Proponents of the view can hold that any minimal physical duplicate of... 

If we embrace an abundant conception of properties, then there is a substantive question of which properties are such that they are constitutive properties of events. For example, if disjunction is a property-forming operation, and so there are disjunctive properties, it by no means follows that disjunctive properties can be constitutive properties of events. Also, even if complementation is a property-forming operation, and so there are negative properties, it is a nontrivial question whether negative properties can be constitutive properties of events — whether, that is, omissions are events. 1 will recur to these matters later. The point to note for now is that on an abundant conception of properties, no extant property exemplification account of events counts literally every property as such that it can be a constitutive (or essential) property of an event. One might embrace quantification as a property-forming operation but reject it as an eventforming operation and so reject the claim that functional properties can be constitutive properties of events. Whether functional properties can be constitutive properties of events, and so whether there are functional events in the sense in question, is a controversial issue. The issue, moreover, as I see, is inseparable from the issue of whether such entities would be causes. 

I myself see no compelling grounds for believing that functional events, if such there be, are causes. We indeed have a deep intuition that there is mental causation epiphenomenalism seems patently absurd. Whether functional events (in the role-functionalist sense) are epiphenomena. 

The issue of whether functional events are causes is typically put in terms of whether they are preempted from having effects by their physical realizers. But the issue, as 1 see it, is not one of preemption of any sort. In cases of preemption an event fails to have an effect but would have had the effect had it not been preempted by one or more events, that is, had the other events not had the effect in question. It seems to me that functional events, if such there be, would lack effects, not because in any possible world they will be preempted by their realizers from having effects, but because they are not the sort of entity to figure in causal relations. 

Thus, on Humean grounds, he denies that functional events cause their manifestations.Moreover, he points out that if functional properties do not cause their manifestations, then they do not cause anything their core realizers cause by causing their manifestations. ... 

This concern is raised by appeal to the physical bases for the dispositions, but all that matters is that the dispositions have bases, not specifically what their bases are or whether they are physical. The point about fragility would arise even in a world in which its bases all involved spook-glue. As concerns functional states and events, the concern is that for any manifestation, it is invariably the case that the core realizer (on the occasion in question) brings it about, and so there is no work for the functional state or event to do in bringing it about. The concern arises for any effects of the core realizers or bases (physical or not), even ones that are not neither manifestations of the functional events nor caused by means of the causation of their manifestations. 

Still, little, if any, dialectical traction is to be gained here by appealing to a transference theory of causation to argue that functional events are not causes. For NRP theorists reject transference theories. Moreover, it is, of course, highly controversial whether there is any viable transference theory of causation, even independently of the issue of functional event causation. (For the record, I myself would not defend a transference theory of causation.)... 

Still there may seem to be a serious concern indeed for our present discussion. I remarked earlier that the issue of whether functional events can be causes is independent of the issue of whether supervenience on the physical, physical closure, and the physical effects principle hold. The issue, however, is not independent of the nature of causation. That may well make it seem hopelessly difficult to resolve. 

Andrew Melynk (2003, p. 150) has offered a regularity theory of causation that he maintains allows for functional events to count as causes by virtue of functional event types figuring the antecedents of regularities that are causal laws. The account is as follows ... 

Before asking why they won t be undercutting, let us first note that Melnyk requires that causation-grounding regularities be contingent, which, of course, is standard for regularity theories. Recall, however, that functional event types have manifestations. Their manifestations are the effect types (perhaps conditional effect types) of their core realizers, effect types to which the functional event types are linked by definition. There will, then, be conditional necessitation relations that functional event types bear to their manifestations. When fully ticketed to accommodate all the relevant contingencies of an actual situation, there will be a metaphysically... 

---