Physical and functional objects (continued)
There are three ways to describe the process:
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What is the difference?
I continue a series of articles on modeling by the business analyst of subject areas. In past articles, I showed how we produce a description of things. Let's repeat it again.
To begin with, the world we perceive is four-dimensional space-time. But not the space-time that mathematicians use in their reasoning. Rather, it is the space that physicists use. The difference is that there are no points in the physical world. There are objects that from the point of view of the observer can be considered point. But upon closer inspection, these points can be considered as infinite spaces. We often do not distinguish between the world we perceive and the mathematical abstraction created to describe this perception. In the abstraction created to describe the perceived world, there is the concept of a point. There are no points in the real world. This is a huge difference between the simulated world and its model. In the nondiscrimination of these two entities lies the reason for the part of holivars that emerged on the basis of the previous article . For example, we are not able to perceive a slice of the space-time continuum across the time axis, as ISO 15926 suggests us to do in order to define an event. Therefore, further I will continue the reasoning, without being distracted by such concepts as points, slices of the space-time continuum and other abstract objects. We will work only with 4-D space-time objects that we actually perceive.
In 4-D space-time we choose any arbitrary volume (extent). This extent can be connected, (like a stone, for example), or unlinked (like a school, if it was built, then destroyed, and rebuilt in a new location). For the image of extents, a diagram is often used, in which three spatial coordinates are merged into one — the vertical axis, and the time coordinate is represented as the x-axis. In this view, the related object looks like this:
And unrelated as follows:
The connectivity of the volume or the absence of this connectivity is irrelevant for determining the extent. Next, we call an extent what we want it to be:
Object - then we call it an object,
Event means we call it an event
Operation, then we call it an operation.
Having called the extent an event, we describe it as an event, meaning that the width of the extent in time is zero from the point of view of the narrator. We call it an object, which means we will have to describe the geometric dimensions of the extent, and the temporary ones will no longer have a value, but can be described additionally. Let's call it an operation - you will have to specify time limits, because the operation is described by the beginning and end of the operation in time, and the spatial ones no longer matter, but can be described additionally.
Next, we share our view of the extent with other subjects. We begin the description of an extent only with facts, since facts are the description of an extent from the point of view of its physical properties. If we begin the description immediately from a subjective point of view, it will be a subjective description, devoid of factual basis.
The subjective interpretation of an extent is a description of it from some point of view. For example, the extent from some point of view can be a hammer, and on the other - a nail puller. A hammer and a nail puller are subjective descriptions of the same extent — a piece of iron. It is clear that the points of view on the extent - a lot. Therefore, a single physical object can have multiple interpretations.
Treatments can be combined, subtracted, find intersections. For example, if an event has two interpretations: one is a victory and the other is a defeat, then there is an association of these interpretations: victory and defeat.
Combining interpretations is used to describe the functions of an enterprise. But I will tell about it after we classify descriptions of extents (not in this article).
In the process of researching the subject area, it may turn out that, from the point of view of modeling goals, the extent boundaries are chosen incorrectly. Then the subject selects other boundaries of the extent studied and repeats the process of describing it, and then gives a subjective assessment of this extent. It may happen that it is convenient for one subject to describe the extent as an event, and another as an operation. Then there is a conflict than to consider the extent? Event or operation? In fact, it should be possible to consider the extent from one and the other points of view. Such a possibility should be embedded in the methodology of the description of the subject area. For example, in ARIS there is an opportunity to depict an extent as an event on one diagram, and to depict it as an operation on another. For example, the event delivery of finished products to the warehouse with a certain degree of detail may turn into an operation of delivery of finished products to the warehouse. Therefore, what we consider the extent, what methods we use to describe this space - we decide, depending on the goals of modeling. And since each extent, in addition to being considered as an object, event, or operation, has many subjective interpretations, the modeling of these points of view should also be supported by the methodology of modeling the subject area. Now this possibility is absent in the notation, which forces analysts to use certain religious considerations in order to choose one of the many possible interpretations. This concludes the domain modeling and this completes the description of our picture of the world.
In this article I will continue to study the term event. But now I will consider not just a physical event, as was the case in the previous article , but consider a functional event.
This event, which is different from the physical presence of a point of view on it.
Recall how in the last article the caretaker describes the work of the lighthouse. He divides the lighthouse into classes of states: "A fire is being extinguished" and "A fire is burning." The events between these states he describes as "Quenching stopped" and "Ignition stopped."
The state description looks like this:
This activity can be depicted in the form of a process diagram, linking states with events separating them.
This diagram shows that the state and the operation are objects of the same nature, because both are described by two events: the beginning of the state (operation) and the completion of the state (operation).
Question: are the intermediate events in the diagram above, are these physical or functional events? Another chart will help us to answer this question, in which the same events have a completely different name:
Thus, we see that functional events are depicted in the diagrams. If we recall that interpretations of events can be combined, then we can redraw the diagram in such a way as to take into account both points of view:
What is a physical event in our case? This is the event when the lighthouse keeper is sitting on the bench and meditating. In this brief moment, he gathers his strength to continue his work. At the same time, the fire is either lit or extinguished. All these facts together constitute a physical event.
Now consider the operation. For them, the same laws apply as for events: the division into physical and functional. And we must remember that the names of functional operations are written on the diagrams, but not physical ones.
Suppose we have 3 analytics, which are in front of the coffee machine. They have the task to describe the interaction of this particular subject with this automaton. A subject approaches, analysts take pens and start recording.
The first analyst drew the following interaction scheme:
The second one is:
And the third one is:
All diagrams are correct, but in them different names denote different functional operations belonging to the same extent. For example, the operation “Pay money” and the operation “Accept money” are two functional operations that describe one physical operation from different points of view. The first point of view is the point of view of the subject. The second point of view is that of the coffee makers. The third point of view is the point of view of the baton, which (point of view) concentrates on the question of which actor is waiting for the actor. Depending on the purpose of modeling, we use one or another point of view. If we model the subject's behavior, then the first one. If we simulate the operation of an automaton, then the second. If we depict objectivity, then the third. I said that you can combine points of view. Practice it yourself.
The physical operation is the extent, which includes the subject who throws coins into the coin acceptor, a coin-operated automatic machine and a counter that is incremented.
I repeat that the same extent can be considered both an event and an operation as well as an object. Therefore, we can assume that the temporary part of the door handle is an object, if we go to describe its geometric dimensions, an event, if we describe the event “Door has opened” and operation, if we describe an operation to open the door.
It is believed that the state or operation is described by initial and final events. I agree with this, but with one reservation. If an event is a moment (as is customary in ISO), then a contradiction arises when trying to determine the exact moment when it occurred. For example, when exactly did the event "Battle of Kulikovo" happen? There is no such moment. If we assume that the event is a 4-D extent, then we get another contradiction. It turns out that the extent of the operation has common parts with the extent of the event. And this means that the description in the form of an operation that has a beginning and an end is only an approximate description of reality. Here I agree. All our descriptions are just some approximate models that describe real objects in a rather simplistic way. This simplification allows us to reduce the description to an acceptable level of detail required for modeling purposes. As a result, reality and its model correspond approximately as follows:
Sometimes the length of what we call an event is equal to the length of the operation that this event describes. Examples come up with yourself.
So, we realized that one of the ways to use events is to divide the space-time into temporary parts. Each part is a state, or operation, and an event is a conditional boundary between them. There are several ways to describe an event.
The full classification of extents descriptions has not yet been given, and therefore at this stage you can just play around. For example, events can be described using boundary states. There is one state of the system, there is a second, and both are described. The event is declared as a transition from one state to another, which is depicted by an arrow on the state diagram. For example, there is a tomato green state and a tomato red state. The transition between these states is an event. We are well aware that the transition has a non-zero time interval. However, from the point of view of the narrator, the width of this interval is irrelevant. The event description includes a description of two states: a tomato green and a red tomato, as well as a time interval during which a change of states occurred. For example, on the night of August 5, the 6th tomato ripened.
Another way to describe an event is to describe it as a state. For example, the event "Firing started" can be described as: "The caretaker is resting."
In ISO 159126, an event is a moment in time. And the interpretation of the moment of time is as follows: this is a slice of 4-D space-time perpendicular to the time axis. That is, this is the whole universe at time t. How is this different from the definition given by us? First, why do we need the whole universe? We work in a limited area of ​​space. And the simultaneity in this area is determined by us visually (on the same meadow), chronometers (on the globe) and some kind of theory of relativeness within near space. But, as soon as we begin to understand what simultaneity in general is, we get a collision and the impossibility of this definition. Secondly, the cross section of the universe is a geometric abstraction that we tried to get rid of with all our strength. After all, the definition that I gave is understandable from the point of view of common sense. And what ISO gives is not from common sense, but from mathematical abstraction (exactly what Kolmogorov said in his textbook on geometry for the 6th grade!) If we accept the definition of ISO 15926, then the question arises: which of the moments considered an event? For example, the analyst may ask: “What is the event“ the client has come? ”The answer may be:“ This is the moment when the top of his head crossed the plane of the office doorway ”Do you like this definition of an event? I am not, because I will immediately take an interest, “what is the top of the head?” And “what is the doorway?” And so on. Therefore, the inherent definition of an event is turned upside down. It includes what we do not need - the whole universe, and even an abstraction, which is unthinkable to work with! Mine is completely justified, because it is always locally (limited by the framework of the modeled space), and understandable.
')
What is the difference?
Description of things
I continue a series of articles on modeling by the business analyst of subject areas. In past articles, I showed how we produce a description of things. Let's repeat it again.
Nature of space time
To begin with, the world we perceive is four-dimensional space-time. But not the space-time that mathematicians use in their reasoning. Rather, it is the space that physicists use. The difference is that there are no points in the physical world. There are objects that from the point of view of the observer can be considered point. But upon closer inspection, these points can be considered as infinite spaces. We often do not distinguish between the world we perceive and the mathematical abstraction created to describe this perception. In the abstraction created to describe the perceived world, there is the concept of a point. There are no points in the real world. This is a huge difference between the simulated world and its model. In the nondiscrimination of these two entities lies the reason for the part of holivars that emerged on the basis of the previous article . For example, we are not able to perceive a slice of the space-time continuum across the time axis, as ISO 15926 suggests us to do in order to define an event. Therefore, further I will continue the reasoning, without being distracted by such concepts as points, slices of the space-time continuum and other abstract objects. We will work only with 4-D space-time objects that we actually perceive.
Determination of extent boundaries
In 4-D space-time we choose any arbitrary volume (extent). This extent can be connected, (like a stone, for example), or unlinked (like a school, if it was built, then destroyed, and rebuilt in a new location). For the image of extents, a diagram is often used, in which three spatial coordinates are merged into one — the vertical axis, and the time coordinate is represented as the x-axis. In this view, the related object looks like this:
And unrelated as follows:
The first step in exploring
The connectivity of the volume or the absence of this connectivity is irrelevant for determining the extent. Next, we call an extent what we want it to be:
Object - then we call it an object,
Event means we call it an event
Operation, then we call it an operation.
Having called the extent an event, we describe it as an event, meaning that the width of the extent in time is zero from the point of view of the narrator. We call it an object, which means we will have to describe the geometric dimensions of the extent, and the temporary ones will no longer have a value, but can be described additionally. Let's call it an operation - you will have to specify time limits, because the operation is described by the beginning and end of the operation in time, and the spatial ones no longer matter, but can be described additionally.
Next, we share our view of the extent with other subjects. We begin the description of an extent only with facts, since facts are the description of an extent from the point of view of its physical properties. If we begin the description immediately from a subjective point of view, it will be a subjective description, devoid of factual basis.
Facts and their interpretation
We often come across a description of subjective evaluation instead of a description of facts. For example, at the interview the candidate tells us the information: my boss was a real worker! This candidate forgets to describe the facts, going straight to the description of the subjective perception of these facts. It is clear that not everyone will agree with this assessment, and therefore it is better to always adhere to the facts and only the facts, the interpretation of which should be given to the listener. After the facts are described and studied, it is possible to proceed to the interpretation of these facts.
The second step in exploring
The subjective interpretation of an extent is a description of it from some point of view. For example, the extent from some point of view can be a hammer, and on the other - a nail puller. A hammer and a nail puller are subjective descriptions of the same extent — a piece of iron. It is clear that the points of view on the extent - a lot. Therefore, a single physical object can have multiple interpretations.
Treatments can be combined, subtracted, find intersections. For example, if an event has two interpretations: one is a victory and the other is a defeat, then there is an association of these interpretations: victory and defeat.
Combining interpretations is used to describe the functions of an enterprise. But I will tell about it after we classify descriptions of extents (not in this article).
Synthesis and analysis
In the process of researching the subject area, it may turn out that, from the point of view of modeling goals, the extent boundaries are chosen incorrectly. Then the subject selects other boundaries of the extent studied and repeats the process of describing it, and then gives a subjective assessment of this extent. It may happen that it is convenient for one subject to describe the extent as an event, and another as an operation. Then there is a conflict than to consider the extent? Event or operation? In fact, it should be possible to consider the extent from one and the other points of view. Such a possibility should be embedded in the methodology of the description of the subject area. For example, in ARIS there is an opportunity to depict an extent as an event on one diagram, and to depict it as an operation on another. For example, the event delivery of finished products to the warehouse with a certain degree of detail may turn into an operation of delivery of finished products to the warehouse. Therefore, what we consider the extent, what methods we use to describe this space - we decide, depending on the goals of modeling. And since each extent, in addition to being considered as an object, event, or operation, has many subjective interpretations, the modeling of these points of view should also be supported by the methodology of modeling the subject area. Now this possibility is absent in the notation, which forces analysts to use certain religious considerations in order to choose one of the many possible interpretations. This concludes the domain modeling and this completes the description of our picture of the world.
Developments
In this article I will continue to study the term event. But now I will consider not just a physical event, as was the case in the previous article , but consider a functional event.
Functional events
This event, which is different from the physical presence of a point of view on it.
Recall how in the last article the caretaker describes the work of the lighthouse. He divides the lighthouse into classes of states: "A fire is being extinguished" and "A fire is burning." The events between these states he describes as "Quenching stopped" and "Ignition stopped."
The state description looks like this:
This activity can be depicted in the form of a process diagram, linking states with events separating them.
This diagram shows that the state and the operation are objects of the same nature, because both are described by two events: the beginning of the state (operation) and the completion of the state (operation).
Cyclic processes
Here, I ran a little ahead and showed you process diagrams that can be called cyclic (the state of the system goes through the states of the same classes cyclically (“extinguished”, “lit”). But if you look closely at the real processes, you will see For example, the operation “Application acceptance” is preceded by the operation “Waiting for a client with a request.” It begins with the event “Customer applied” and ends with the operation “Waiting for acceptance of application”, which, in turn, ends with the event “Customer applied”. Sansar Her mother)).
The reason for which very few people pay attention to this is that automated systems do not simulate customer expectations, but perform this operation.
The reason for which very few people pay attention to this is that automated systems do not simulate customer expectations, but perform this operation.
Night, street, lantern, pharmacy,
Senseless and dim light.
Live for at least a quarter of a century - Everything will be so. There is no outcome.
If you die, you will start again
And everything will repeat as before:
Night ice channel ripples
Pharmacy, street, lantern.
Question: are the intermediate events in the diagram above, are these physical or functional events? Another chart will help us to answer this question, in which the same events have a completely different name:
Thus, we see that functional events are depicted in the diagrams. If we recall that interpretations of events can be combined, then we can redraw the diagram in such a way as to take into account both points of view:
Physical event
What is a physical event in our case? This is the event when the lighthouse keeper is sitting on the bench and meditating. In this brief moment, he gathers his strength to continue his work. At the same time, the fire is either lit or extinguished. All these facts together constitute a physical event.
Operations
Now consider the operation. For them, the same laws apply as for events: the division into physical and functional. And we must remember that the names of functional operations are written on the diagrams, but not physical ones.
Functional operations
Suppose we have 3 analytics, which are in front of the coffee machine. They have the task to describe the interaction of this particular subject with this automaton. A subject approaches, analysts take pens and start recording.
The first analyst drew the following interaction scheme:
The second one is:
And the third one is:
All diagrams are correct, but in them different names denote different functional operations belonging to the same extent. For example, the operation “Pay money” and the operation “Accept money” are two functional operations that describe one physical operation from different points of view. The first point of view is the point of view of the subject. The second point of view is that of the coffee makers. The third point of view is the point of view of the baton, which (point of view) concentrates on the question of which actor is waiting for the actor. Depending on the purpose of modeling, we use one or another point of view. If we model the subject's behavior, then the first one. If we simulate the operation of an automaton, then the second. If we depict objectivity, then the third. I said that you can combine points of view. Practice it yourself.
Physical surgery
The physical operation is the extent, which includes the subject who throws coins into the coin acceptor, a coin-operated automatic machine and a counter that is incremented.
One extent - different objects?
I repeat that the same extent can be considered both an event and an operation as well as an object. Therefore, we can assume that the temporary part of the door handle is an object, if we go to describe its geometric dimensions, an event, if we describe the event “Door has opened” and operation, if we describe an operation to open the door.
Intersection extents
It is believed that the state or operation is described by initial and final events. I agree with this, but with one reservation. If an event is a moment (as is customary in ISO), then a contradiction arises when trying to determine the exact moment when it occurred. For example, when exactly did the event "Battle of Kulikovo" happen? There is no such moment. If we assume that the event is a 4-D extent, then we get another contradiction. It turns out that the extent of the operation has common parts with the extent of the event. And this means that the description in the form of an operation that has a beginning and an end is only an approximate description of reality. Here I agree. All our descriptions are just some approximate models that describe real objects in a rather simplistic way. This simplification allows us to reduce the description to an acceptable level of detail required for modeling purposes. As a result, reality and its model correspond approximately as follows:
Sometimes the length of what we call an event is equal to the length of the operation that this event describes. Examples come up with yourself.
Ways to Describe Events
So, we realized that one of the ways to use events is to divide the space-time into temporary parts. Each part is a state, or operation, and an event is a conditional boundary between them. There are several ways to describe an event.
The first way to describe events
The full classification of extents descriptions has not yet been given, and therefore at this stage you can just play around. For example, events can be described using boundary states. There is one state of the system, there is a second, and both are described. The event is declared as a transition from one state to another, which is depicted by an arrow on the state diagram. For example, there is a tomato green state and a tomato red state. The transition between these states is an event. We are well aware that the transition has a non-zero time interval. However, from the point of view of the narrator, the width of this interval is irrelevant. The event description includes a description of two states: a tomato green and a red tomato, as well as a time interval during which a change of states occurred. For example, on the night of August 5, the 6th tomato ripened.
Partridge Error
That's exactly what Chris Partridge needed in the Business Objects: Re-Engineering for Re-Use book to do when describing the “Tomato ripened” event. He also invented a certain “Complex event”, which differs from the simple one in that it supposedly consists of simple ones, but the author could not describe it clearly. Here is an example from his book in which he gives a space-time diagram.
The second way to describe events
Another way to describe an event is to describe it as a state. For example, the event "Firing started" can be described as: "The caretaker is resting."
What I don't like in ISO 15926
In ISO 159126, an event is a moment in time. And the interpretation of the moment of time is as follows: this is a slice of 4-D space-time perpendicular to the time axis. That is, this is the whole universe at time t. How is this different from the definition given by us? First, why do we need the whole universe? We work in a limited area of ​​space. And the simultaneity in this area is determined by us visually (on the same meadow), chronometers (on the globe) and some kind of theory of relativeness within near space. But, as soon as we begin to understand what simultaneity in general is, we get a collision and the impossibility of this definition. Secondly, the cross section of the universe is a geometric abstraction that we tried to get rid of with all our strength. After all, the definition that I gave is understandable from the point of view of common sense. And what ISO gives is not from common sense, but from mathematical abstraction (exactly what Kolmogorov said in his textbook on geometry for the 6th grade!) If we accept the definition of ISO 15926, then the question arises: which of the moments considered an event? For example, the analyst may ask: “What is the event“ the client has come? ”The answer may be:“ This is the moment when the top of his head crossed the plane of the office doorway ”Do you like this definition of an event? I am not, because I will immediately take an interest, “what is the top of the head?” And “what is the doorway?” And so on. Therefore, the inherent definition of an event is turned upside down. It includes what we do not need - the whole universe, and even an abstraction, which is unthinkable to work with! Mine is completely justified, because it is always locally (limited by the framework of the modeled space), and understandable.
Source: https://habr.com/ru/post/247225/
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