I have an XOR gate connected to 4 activities. Each activity is then connected to the same subprocess. Not looking for answers or solutions - just general advice related to BPMN modelling.
My issue is that I think this design pattern could be modelled better. I'm also not sure if it is valid. Does anyone have any pointers in the right direction?
I'm essentially trying to create a for each component, do inspection (inspection is same set of steps, but different component)
If you really look out for validity you may use a configurable bpmn linter, like https://github.com/bpmn-io/bpmnlint (I have no affiliation with this project).
With such a tool you can statically check against the common design errors.
Regarding your second question whether "this is valid", I would say : Almost.
Diagramme 1 : The closing XOR gateway should be placed before the "Inspect component" activity. The four arrows of the individual "Locate component xxx" activities should all merge into this gateway, thereby mirroring the initial XOR gateway whence the four arrows leave. From that merging/closing XOR gateway, you should draw a single arrow towards "Inspect component".
Diagramme 2 : You should equally place a closing XOR gateway at the end of your process, just before the end event, in order to merge the arrows from the "No" branch of the third XOR gateway and the "Record other abnormalities" activity. Otherwise, your process will never finish in case you carry out "Record other abnormalities" because there is no outgoing arrow from that activity.
While the points above are objective because they relate to the BPMN syntax, the answer to your first question, whether "this design pattern could be modeled better", is based on opinion. Here is what I would try to improve
In diagramme 1, the question "Component successfully inspected?" will never be answered with "Yes". What happens when all components have indeed been inspected ? Your process would be stuck.
I have a feeling you do not need the individual "Locate component x" activities at this level. In the diagramme, the location of each component does not change the course of subsequent activities. I would rather see this activity as the first task in the "Inspect component" sub-process. But if you insist on modeling it this way, then I would turn the exclusive gateway into an inclusive one and add an arrow that goes straight to the end event. That way, multiple inspections or none can happen and you will not get stuck.
Considering the two previous points, you can represent a "For each" loop with a sequential activity as shown below. The three horizontal lines signify that you repeat the sub-process sequentially (as opposed to in parallel). I would see this process itself as a sub-process of a wider process such as "Maintain vehicle".
Related
I want to check what is the definition of «iterative» in expansion regions in activity diagrams. For me personally this was never a question because I understand it as letting me do a For loop, e.g.,
For i=1 to 10
Do-Something // So it does it 10 times
End For
However, while I was presenting my UML diagram to an audience, an engineer team leader (not a UML maven) objected against the term ‘iterative’, because he understood ‘iterative’ to mean an 'iterative process' such that each step improves a result. I am also aware of this definition, but I assume the UML definition is not that, but rather means a simple For-Loop.
Please confirm that the UML definition of «iterative» and iteration is like a simple For-loop. Or otherwise, if so.
No, it has a different meaning. UML 2.5 states in p. 480:
The mode of an ExpansionRegion controls how its expansion executions proceed.
If the value is iterative, the expansion executions must occur in an iterative sequence, with one completing before another can begin. The first expansion execution begins immediately when the ExpansionRegion starts executing, with subsequent executions starting when the previous execution is completed. If the input collections are ordered, then the expansion executions are sequenced in the order induced by the input collection. Otherwise, the order of the expansion executions is not defined.
Other values for this keyword are parallel and stream. You can guess that behavior defined in a parallel region can be executed in parallel. stream is a bit more complicated and you might read on that page in the UML spec.
The for-loop itself comes from the input collection you pass to the region. This can be processed in either of the above ways.
tl;dr
So rather than a for loop the keyword «iterative» for the region tells that it's behavior may not be handeled in parallel.
Ahhh, semantics...
First a disclaimer - I am not a native English speaker. Yet my believe both my level of English and IT experience are sufficient to answer this question.
Let's have a look at the dictionary definition of iterative first:
iterative adjective
/ˈɪtərətɪv/
/ˈɪtəreɪtɪv/, /ˈɪtərətɪv/
(of a process) that involves repeating a process or set of instructions again and again, each time applying it to the result of the previous stage
We used an iterative process of refinement and modification.
an iterative procedure/method/approach
The highlight with a script font is mine.
Of course this is a pure word definition, not in the context of software development.
In real life a process can quite easily be considered repetitive but in itself not really iterative. Imagine an assembly line in a mass production factory. On one of the positions a particular screw/set of screws is applied to join two or more elements. For every next run, identical set of elements the same type and number of screws is applied. There is a virtually endless stream of similar part sets, each set consisting of the same type of parts as previously and requiring the same kind of connection. From the position perspective joining the elements is a repetitive process but it is not iterative, as each join is applied to a different set of elements - it does not apply to those already joined.
If you think of a code, it's somewhat different though. When applying a loop, almost always you have some sort of a resulting set impacted by it and one can argue that with every loop step that resulting set is being further changed, meaning the next loop step is applied on the result of the previous step. From this perspective almost every loop is iterative.
On the other hand, you can have a loop like that:
loop
wait 10
while buffer is empty
read buffer
You can clearly say it is a loop and nothing is being changed. All the code does is waiting for a buffer to fill. So it is not iterative.
For UML specifically though the precise meaning is included in qwerty_so's answer so I will not repeat it here.
I am having trouble getting the terminals to pass any data to what they are connected to because the controls they connect to are in a while loop. My frustration level is high since I would have already had this done if I wrote it in C.
First, let me say this might get a little long so if you don't want to read it, then don't. Here goes. I have watched a couple of tutorials, read a lot, and even tried a few things out in code. I get why this can't be done directly in a while loop. Having said that, it seems that I have no choice but to use while loop(s) in my VI.
My VI is loosely based on Queued Message Handler in the Templates section of creating a new VI. I have 2 things that must take place. One - I have created a TCP client where I constantly send messages to get status from the equipment I am communicating with. This is a timed event and must be handled in a while loop so I can maintain the connection to the server. I am not doing the Open, Send, Close, Reopen, Send, Close, etc. type of message handling. Too inefficient. This is the lower half of the example template.
Second - On occasion the user will press a button on the front panel which creates a message that is sent to the equipment to make it do something. And this, it would seem, needs to be in a while loop also, hence my problem. Some/most of the controls exist with the event structure. This is the top half of the example template.
I actually have this working as a front panel, but every thing is in just one while loop and I cannot get the terminals to work. Here is where my confusion comes in, if I am passing something to the while loop, I only get its value once and if it changes, you don't get that change, and if you are passing the data out of the while loop, you only get it when the loop ends. These two things are really baffling me. How can pass data that changes while using a while loop, because I have to, but the while loop breaks using the terminals. Seems circular. The TCP communications cannot stop, and I cannot find an example of how to do this using my friend Google. Am I the only person on this planet that needs to do this? Doubt it.
Not going to show my code, as this in not a code problem. It is an understanding how LabView does things vs. how you would just write the code in C using some library. And also just being unfamiliar with all the things you can do in LabView, not to mention how things are different. I don't know what I don't know, but I can learn.
I want to be able to give the VI I have created to any user and let them use it to control my equipment. If they just want to run it as a front panel, or if they want to use it as a Sub VI that is OK too. I just need to be able to make the terminals actually pass data when used that way.
Thanks, I did order a book on LabView today, but I won't get it soon. I really need to put this problem to bed.
Cannot help that much without seeing the code. But I can try to give you a little bit of an idea of what is going on.
Dataflow is an important concept to understand in LabVIEW. elements (VIs, loops, etc.) will not start until all of their inputs (ie. terminals) have been received or set by something called before, and then they only take their inputs once. If your terminal is outside the loop, then the loop can only read it's starting value. (See "Infinite Loops" on this page). A simple way of solving this would be to put the terminal inside of the loop rather than outside, so it is then read on every iteration of the loop.
As for passing values outside of the loop, there are a number of methods for this. Again, because of dataflow, you will not usually be able to access the value of something inside the loop until the loop finishes executing. However, there are a number of ways to read those values in a different loop. Local or global variables would be the simplest way, but they are not recommended by NI. The proper way of handling this is using something on the synchronization pallet. More info on the options can be found here.
Seeing as you are basing something on the Queued Message Handler, a queue might be a good way to start. LabVIEW has built in examples of code to show you how to use these functions.
Loop synchronization and asynchronous programming are fundamental concepts for writing LabVIEW code. If these are not concepts you are familiar with, I would say that you will gain a lot from showing others your actual code and having people help you with the issues. If you are concerned about sharing something proprietary, try making a simple example and posting that code instead to understand the concepts better.
Event structure to react to evr8and functional global to pass data out.
Suggest pasting block diagram.
I have the following case.
A reservation, this reservation be canceled, it can be newly created it can be Confirmed it can be rejected.
There might be different reasons for cancelation. Lets say the reservation has expired, or it may have not been processed within certain timelimit or some other reason.
In order for a reservation to be confirmed a multiple sub - transactions should be performed. This mean that there is a flow within the Confirmation itself. The solution my team came with is some sort of work table holding many different statuses. Which is fine. I felt the need to uniquely identify the state of a reservation by declaring a field ReservationStatus that depicts certain variation of statuses that are already defined in the table. In this case the Reservation status would be NEW,CONFIRMED,CANCELED,REJECTED. Each state will depict certain variation of statuses in the work table.
My team was convinced that this is adding additional complexity. I think this is the opposite it simplifyes the flow. It also declares a natural discriminator and polymorphism. We are supposed to use Queues and asynchroneus processes.
How can I actualy jsutify that we should have such column it apears the arguments I already mentioned were not enough and deep down inside I know I am right :)?
Wanted this to be a comment but it came out too long so here it goes.
#AlexandarPetrov I would add the following questions:
Do all the Statuses concretely represent every State a Reservation could have?
Are there clear rules for all Status migration paths? For e.g. Expired -> CONFIRMED and so forth.
Do you need to model the state changes? And is it a finite state machine?
I'd personally expose the status field but only if it is concrete enough by itself to define state. For e.g. I've seen cases where there are 2 layers of statuses - status and sub-status. In a case like that boundaries are lost and state becomes a complex VO rather than a simple field and state transition rules could become blurry.
Additionally:
For me it seems like Event Sourcing and CQRS could be a good fit for all those Reservations. Especially having in mind the complex flows you mention. Then transitions will be events being applied and the statuses - a simple way to expose state. Tracking status changes separately will also be needless as the Event Stream holds all historical data.
Finally:
How can I actualy jsutify that we should have such column it apears the arguments I already mentioned were not enough and deep down inside I know I am right :)?
Well at the end you can always put your foot down and take responsibility. And if it turns out to be a wrong decision in time - bare the responsibility and admit the mistake.
I'm trying to create a survey containing several slider-type questions, asking participants to select a point on a line to indicate their experience of different emotions. For example:
Not at all anxious -----------------------|---------------------Extremely anxious
These questions are meant to serve as visual analogue scales (VAS), often used in my field but typically administered via paper/pen. A digital VAS would be very useful for my research, but I have 2 problems with the Qualtrics format.
First, I need to hide the vertical slider until participants selects a point on the line (in effect removing any visual "starting point" that can influence responses). Second, I can't force participants to respond to every question, so I need a way to distinguish those who skip a question/don't answer (including code to check if the slider was displayed or not displayed when the participant chooses to continue to the next question might work, so that Qualtrics stores no response for that question if the slider is still hidden).
Thanks for the help! I'm not a coder, so I would really value any and all advice!
The docs for NSSpeechRecognizer state that complex, multi-step actions can be executed from single spoken commands, such as:
“schedule a meeting with Adam and John tomorrow at ten o’clock.”
I'm able to execute simple commands which are preprogrammed, but I don't see how the above could be interpreted using the class. It seems like
“schedule a * with * *”
should be a command. Any idea if something like this is possible? Or are we just supposed to pass an infinite number of possible commands to the recognizer?
It does not appear to me from the NSSpeechRecognizer documentation that it will support using complex phrases like the example you have given. To get the semantic meaning from a phrase like this you would use a system that supports multislot grammars like most IVR systems that support the VoiceXML standard. It looks to me that this speech recognition API only supports passing in simple commands as an array and not specifying complex grammar rules. With this type of system you would have to implement what is called a directed dialog, which might go something like this:
C: What would you like to do?
U: Schedule a meeting.
C: Tell me the first person that you would like to attend?
U: Adam.
C: Tell me the next person that will attend or say "done" if the attendee list is complete.
U: John.
C: Tell me the next person that will attend or say "done" if the attendee list is complete.
U: Done.
C: What day is this meeting?
U: Tomorrow.
C: What time is the meeting?
U: Ten O'Clock.
C: Thank you. Your meeting has been scheduled.
Using a directed dialog you can restrict the expected commands/utterances to a much more defined list. Although your list of possible names could be quite large unless you cull them from a users contact list.
My interpretation of the docs is that you would need to accumulate and operate on any compound state on your own. You provide NSSpeechRecognizer with a set of discrete words/phrases that it should recognize as 'commands', and it reports to you when it has recognized them.
For the example you've given, I think you'll run into problems when you get to the "Adam and John" part -- it's not an arbitrary dictation engine. But, for fun, let's try to imagine how we might do this:
You might tell it you want to recognize the following phrases as 'commands':
"schedule a"
"meeting" (and perhaps "appointment", "playdate", etc)
"with"
"Adam and John"
"tomorrow" (and probably other related things like "today", "two days from now", all the days of the week, etc)
"ten o'clock"
As words/phrases are recognized, you could create a stack of semantically related words/phrases based on previously recognized words/phrases. So, for instance, it recognizes the "schedule a" phrase, and you know that there should be more info coming to fill out the semantic context, so you push that phrase onto the stack. Next, it recognizes "meeting". Your app says 'sure, a meeting is something that can be scheduled' and pushes it onto the stack as well. If the next word it recognized wasn't germane to the previously-recognized "schedule a" command, then it would clear the stack. If, at any point, the elements on the stack satisfy some pre-defined criteria for a fully formed expression of semantic intent, then your app can take the appropriate action based on that intent. There's obviously a temporal element to this as well. If the next thing required to establish semantic context doesn't arrive in a reasonable amount of time, the semantic context stack should get cleared.
A similar system, conceptually, is the iOS/MacOS touch/trackpad gesture recognition system. When a tap touch happens, the OS has to recognize the single tap, and acknowledge the possibility that that is the entire user intent, but it also has to manage the possibility that it might receive another tap very shortly, turning the single tap into a double tap. It will have to accumulate this state over time, and infer the user intent by looking at the combination of discrete events.
You're not going to get such functionality from NSSpeechRecognizer for free, and being that it's not a dictation engine, you also won't get arbitrary 'tokens' from it (like "Adam and John", assuming you're not registering some giant list of names all as potential commands.) Even so, that doesn't mean it couldn't be leveraged to do some pretty neat stuff using a mechanism like I described. It's just that you're gonna have to write it yourself.
Good luck!