System behaviour

The behaviour of a system in interaction with certain attackers and users is defined by the possible sequences of its global states. This can be done in a natural way for the above-mentioned models of programs and connections. In particular, executing a protocol consisting of interactive functions means applying the actual functions many times. One such sequence of global states is called a protocol execution or 

It may not be immediately clear why one can assume that attackers have a strategy — couldn t they make a new decision what to do next after every step of communication with the correct entities However, this is equivalent One can describe a global strategy as a complete, probabilistic decision tree, as in game theory, where for every history and every new reaction of the correct entities, the possible actions of the attackers in the next step, each with a probability, are listed. 

In a synchronous system, all messages sent at the end of one round are guaranteed to be received at the beginning of the next round. In practice, synchronism presupposes that messages are guaranteed to arrive within a certain period of time. 

To be realistic, synchronism must be defined differently for attackers They may send their own messages last in a round, so that they can already base their decision on the messages sent by others. This is called rushing attackers, see [Beav91, MiRo91]. 

Some parts of a behaviour are of particular interest One is the restriction of the actions to those at the interface, i.e., the service. Another is the restriction to a given set of access points, because that may be what a set of honest users sees from the system. The view of an attacker is the restriction of a run to everything the attacker 

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The types of system behaviour predicted, by the above analysis are depicted in Figs. 3.16 and 3.17. The phase-plane plots of Fig. 3.17 give the relation of the dependant variables C and T. Detained explanation of phase-plane plots is given in control textbooks (e.g., Stephanopoulos, 1984). Linearisation of the reactor model equations is used in the simulation example, HOMPOLY. 

In this chapter only the first step in the specification of the control systems for a process will be considered the preparation of a preliminary scheme of instrumentation and control, developed from the process flow-sheet. This can be drawn up by the process designer based on his experience with similar plant and his critical assessment of the process requirements. Many of the control loops will be conventional and a detailed analysis of the system behaviour will not be needed, nor justified. Judgement, based on experience, must be used to decide which systems are critical and need detailed analysis and design. 

Vary the value of the equilibrium constant m and study its effect on system behaviour. 

Central nervous system - behavioural activity, sensory/motor responses and body temperature... 

James Bailey has said, talking about the inextricable coupling between a model and its intended application (citing Casti) that Basically the point of making models is to be able to bring a measure of order to our experience and observations, as well as to make specific predictions about certain aspects of the world we experience [108]. So models are not an end in themselves but should be looked more as tools to think and calculate logically about what components and interactions are important in a complex system. Mathematical models can also be justifiable to minimize the experimental effort, predict system behaviour and identify new research avenues [10]. 

System Behaviour Packing Pressure Liquid flow-Gas ... 

Obviously, if as t —> oo the stationary solution dnj( )/d = 0 exists, indeed the asymptotic solution rij(oo) of (2.1.1) is one of the solutions n(- of the set (2.1.14). Here we have an example of a simple but very important case of a stable stationary solution. Other stationary points cannot be ascribed to the asymptotic solutions, i.e., n nj(oo), but they are also important for the qualitative treatment of the set of equations. Note that striving of the solutions for stationary values is not the only way of chemical system behaviour as —> oo another example is concentration oscillations [4, 7, 16]. Their appearance in a set (2.1.2) depends essentially on a nature of... 

We study here the A + 5B2 —> 0 reaction upon a disordered square lattice on which only a certain fraction S of lattice sites can be accessed by the particles (the so-called active sites). We study the system behaviour as a function of the mole fractions of A and B in the gas phase and as a function of a new parameter S. We obtain reactive states for S > Sq where Sq is the kinetically defined percolation threshold which means existence of an infinite cluster of active sites. For S < Sq we obtain only finite clusters of active sites exist. On such a lattice all active sites are covered by A and B and no reaction takes place as t —> 00. 

In curves 4 the system behaviour is shown under the conditions of curves 3 but now including the effect of A-desorption, equation (9.1.42). In this case we obtain a reactive state. We observe a phase transition of the first order at y — 0.268. For Yco < U the lattice is completely occupied by particles B. A phase transition point y2 does not exist but we obtain a smooth transition over a wide range of kco Due to the desorption the state poisoned by A does not exist. 

Let us study now a stochastic model for the particular a+ib2 -> 0 reaction with energetic interactions between the particles. The system includes adsorption, desorption, reaction and diffusion steps which depend on energetic interactions. The temporal evolution of the system is described by master equations using the Markovian behaviour of the system. We study the system behaviour at different values for the energetic parameters and at varying diffusion and desorption rates. The location and the character of the phase transition points will be discussed in detail. 

For the case that the A-A and the A-B interactions are both repulsive we obtain a composite system behaviour resulting from the behaviour discussed above. 

To demonstrate this, in Section 9.2.2 we have studied a stochastic model for an extended ZGB-model including diffusion, desorption and energetic interactions as additional steps. We have used different values of the diffusion and the desorption rates and different values for the energetic parameters. In the case of repulsive interactions the system s behaviour is strongly influenced by. Eaa for large values of Yqo and by for small values of kco-The former parameter leads to a smooth phase transition at yi and the latter to a sharp transition at 2/1 The sharpness and the location of the phase transitions depend also on the diffusion and desorption rate of the A particles. The A-diffusion leads to an increase of the value of 2/2 due to the higher reactivity of the A particles. At lower values of Yco the system behaviour is nearly not influenced by the diffusion. The A-desorption increases the values of the critical points and smoothes the phase transition at 2/2- This effect becomes very important if Ca is large. 

Slow relaxations can be exemplified by the system behaviour corresponding to the adsorption mechanism (8) when the parameters % are close to their bifurcation values. 

A new interesting fact is that the application of thermodynamic functions of states together with material balances suggests a non-trivial consideration concerning the system behaviour not only under equilibrium but also in the course of approaching this equilibrium. 

H. Sato (JAEA) presented a paper discussing detection methods and system behaviour assessments for a tube rupture of the intermediate heat exchanger (IHX) for a sulphur-iodine based nuclear hydrogen plant. A rupture could be detected by monitoring the secondary helium gas supply using a control system that monitors the differential pressure between the primary and secondary helium gas supply. Isolation valves would be used to reduce the helium flow between the primary and secondary cooling systems. The study showed that the maximum temperature of the reactor core does not exceed its initial value and that system behaviour did not exceed acceptance criteria. 

The availability of the proposed detection method was evaluated. Furthermore, system behaviour is assessed during the scenario. A system analysis code developed for VHTR systems is used for these calculations. 

IHXTR is one of the potential concerns for the demonstration of nuclear hydrogen production. The detection method of the heat transfer tube rupture of IHX in the HTTR-IS nuclear hydrogen production system was proposed in this paper. In addition, system behaviour was evaluated with a deterministic approach. The results are summarised as follows ... 

KEY WORDS Motor systems behaviour 6-hydroxydopamine nigrostriatal lesions rats monkeys transgenic mice. 

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