Boolean attribute

To capture this invariant we must define the term completed we do so by simply adding a Boolean attribute to Session—and, of course, defining its real-world meaning in the dictionary. 

Because states simply define Boolean attributes, it is easy for states to be tied to the values of other attributes and associations via invariants. So for example, we can write... 

Because states are Boolean attributes, retrieving a state is no different from retrieving any model. The abstract states can still be seen in the refinement, although you must use the abstraction functions to translate from sumpart to content (Figure 6.20). Also, the extra state must be given its own definition. 

For each state, define an invariant that relates it to other attributes in the type model. States are boolean attributes, and can be parameterized just like attributes. 

The states are as you choose them. By a state in a statechart, we mean the truth or falsity of some predicate i.e. just like any boolean attribute, including parameterized attributes as well. A library book is or isn t out on loan it is or isn t withdrawn from circulation it is or isn t on the shelf. Some choices of states are obvious, because they make a significant difference to the postconditions and preconditions of the applicable operations. The point of a statechart is to illustrate these broad relationships between state and actions. But depending on your point of view, you can always choose a different set of states to illustrate — whether the book is or isn t in poor repair, whether it is over 10 years old, whether it is currently passing through the checkout desk, whether it is overdue for return. 

Identify a type with interesting states and transitions. Some don t have any. Any boolean attributes are candidates for states. Similarly, if you have optional attributes or associations, there are frequently states in which those attributes must be defined. Some continuous attributes may have values that signify a qualitative change in behavior e.g. speed > 75mph may qualify as a speeding state. Look also for radical differences in behavior — eg, can be lent or not and for equivalent manual system stages or phases or temporary tags or marks or locations of an item or piece of paperwork. E.g. Book on shelves or held at desk or with member. E.g. hotel reservation in future folder or today pile. 

UML has three distinct constructs that remain largely unrelated to one another an attribute, a role in an association, and a state in a state chart. For example, a pie- and postcondition pair cannot refer to the name of a state. In Catalysis these three constructs are closely related. An association defines a pair of inverse attributes that are drawn differently a state defines a Boolean attribute, and the structure of states in a state chart defines invariants on those attributes. Transitions on a state diagram are thus no more than a graphical depiction of action specifications. This approach provides a simpler core set of constructs with different presentations. Actions on UML state transitions are imperative and appear unrelated to pre- and postspecification of operations. 

The problem with applications to contexts, which are based on field measurements, is that outliers may completely destroy an interesting implication. Hence the scaling process (see Ganter and Wille 1999) must be performed carefully and in fact it is more reasonable to apply concept analysis to contexts on Boolean attributes only. 

OVERFLOW out BIT ANSWER out SIGNED(3 downto 0)) - see Box 6.7 for more information on this attribute attribute BUILTJN.OPERATORS. BOOLEAN attribute BUILTJN OPERATORS of ADD2 entity is FALSE endADD2 ... 

Full-Text Patent Databases. The LEXPAT database on the LEXIS— NEXIS system, the first commercially available full-text patent file, receives its greatest use from patent attorneys and has been relatively unused by other patent information speciaUsts. This may be attributed to search software that is quite different from the type familiar to information speciaUsts, no matter what their preferred host system. This situation has changed with dialog s release of the PATEULL files followed by STN s USPATEULL, both searchable by familiar Boolean techniques and featuring greater... 

We regard as objects primitive concepts such as dates, numbers, and the two Boolean values. You can alter an attribute (such as maxSize) to refer to a different number, but the number itself does not change. Useful basic and immutable attributes of numbers include next and previous, so that, for example, 5. next = 6. (Many tools and languages like to separate primitives from objects in some fundamental way. The separation is useful for the practicalities of databases and the like, but for most modeling there is no point in this extra complication.)... 

These constraints simply navigate parameterized attributes we could use the more conventional syntax a < b instead of a.isLessThan(b). Thus, a predefined type Date has a parameterized attribute < (Date) Boolean, which yields true or false for any given compared date. 

But sometimes we need to disallow certain combinations of attribute values. To do this we can write an invariant a Boolean (true/false) expression that must be true for every permitted snapshot. (We will scope the snapshots by the set of actions to which this applies in Section 3.5.5, Context and Control of an Invariant.)... 

Then the assignQualified invariant corresponds to the following Boolean function, which should evaluate to true upon completion of any external operation invocation. Note that the code form is the same as that of the type model invariant, with each reference to an attribute in the type model expanded to its corresponding representation in the implementation. 

The precondition is also a purely Boolean expression and has no side effects it can refer only to inputs and initial values of attributes. The corresponding postcondition is not guaranteed by the implementor if the precondition did not hold. 

States are often drawn in a state chart showing the states and the relationships between them, as in Figure 3.21. Each state is a Boolean attribute17 an object either is or is not in that state at any time. The structure of states in the state chart defines invariants across these attributes. 

In the Catalysis interpretation, the states in a state chart are Boolean conditions and the transitions are actions. As such, actions may take time there is a gap between one state going false and the next state lighting up (rather like the floor indicator in many elevators).9 Most state charts focus on a given type, and the states are defined in terms of its attributes. 

Define each state as a boolean function of the other attributes. It should be distinct from the other states in the diagram (except those explicitly parallel or nested). If it cannot be made distinct from another state, there is information missing from the model. 

Such state definitions are often combinations of a few boolean terms — some optional link present, some attribute > 0, and so on. Make a table of the combinations, showing how each state has a different combination, and identifying combinations that do not correspond to any state. The complete set of allowed states is an invariant that should be documented for the model. 

A partial listing of the methods operating on the class atom is also shown in Table II. Methods with the compute prefix (e.g., compute-parent-groups, compute-hybridization, and compute-formal-charge) are used to evaluate attribute values. Predicate methods (i.e., methods returning a Boolean value) are represented by the -p suffix. These methods are... 

The left hand side (x) may contain any number of clauses combined by Boolean algebra operators. In all but the simplest expert systems it is possible to include the expert s confidence in the conclusion. A frame describes hierarchical dependencies between objects. In a frame, the upper level (or parent) object passes attributes to the objects beneath it in the hierarchy (children). In other words, children inherit attributes from their parents. For example ... 

Selection of D enables the user to define a search (Figure 4) in terms of all attributes of the wider biological record, now perceived as including the structure (Option C) and values which are specific to particular tests (Option T). The search may include multiple terms, earlier sets and Boolean logic. 

In our presentation here, we omit the formalization of various boolean operators and attributes however, it should be clear how to formsdize these within our logic. We also omit the formalization of process statements however these can be rewritten using wait statements. A significant omission is non-Boolean datatypes. While it is possible to formalize non-Boolean datatypes in a first order polymodal logic, reasoning is much more difficult. 

ABSTRACT In most cases, Model Based Safety Analysis (MBSA) of critical systems focuses only on the process and not on the control system of this process. For instance, to assess the dependability attributes of power plants, only a model (Fault Tree, Markov chain. ..) of the physical components of the plant (pumps, steam generator, turbine, alternator. ..) is used. In this paper, we claim that for repairable and/or phased-mission systems, not only the process but the whole closed-loop system Proc-ess/Control must be considered to perform a relevant MBSA. Indeed, a part of the control functions aims to handle the dynamical mechanisms that change the mission phase as well as manage repairs and redundancies in the process. Therefore, the achievement of these mechanisms depends on the functional/dysfunctional status of the control components, on which these functions are implemented. A qualitative or quantitative analysis method which considers both the process and the control provides consequently more realistic results by integrating the failures of the control components that may lead to the non-achievement of these mechanisms. This claim is exemplified on an industrial study case issued from a power plant. The system is modeled by a BDMP (Boolean logic Driven Markov Process), assuming first that the control components are faultless, i.e. only the faults in the process are considered, and afterwards that they may fail. The minimal cut sequences of the system are computed in both cases. The comparison of these two sets of minimal cut sequences shows the benefit of the second approach. 

Structural constraining attribute attribute MERGE BOOLEAN ... 

Over the years, Ashby has been one of the most prominent names in the field of materials research, with even a selection method being given his name. The key to this method is the ability to translate requirements into materials and processes attributes. The attributes in this context can take different expressions, from numeric as Young modulus. Boolean as recyclability or process compatibility, or ranking (from poor to very good) as in the case of resistance to corrosion. The translation between the application requirements and the materials and processes attributes, a key step in Ashby s method, is performed through (Ashby et al., 2004) ... 

Structure attributes (parameters) of type LOGICAL are elements of the dual set (.T.. F.) where. T. and. F. denote the Boolean constants TRUE and FALSE. The regular set logical ( Tokens of the neutral file language on page 160) formally defines the set of LOGICAL constants. 

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