I am beginner in UML and now I am creating one sequence diagram, problem is I would like to implement DAO interfaces according to user input. How can I draw correctly for implementing Interface in sequence diagram.
You do not draw an interface on a SD. A SD just shows instances (and eventually slots and ports) and messages exchanged along a life line. If you need to show interfaces use a class diagram.
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Specifically, my group is working on thermal modeling of EVs i.e cabin cooling and battery cooling. We have used most elements from the two-phase-fluid sub-library of simscape. But at two connections we want a controlled separation of the refrigerant flow. For that, there is an element called flow divider but it's in the hydraulics sub-library. So how do I use these libraries simultaneously? I'm trying since yesterday but nothings seem to work. Thank you.
In the Thermal Power Library from Modelon, there are two kinds of connectors: flow connector and volume connector.
Based on the tutorial shipped with the library, these two kinds of connectors should NOT be connected with the same kind of connector.
But I checked their code, it seems the codes are the same.
I checked the code in the ThermoSysPro library from EDF and ThermoPower library, too. They also use two kinds of connectors, and the recommendation of connecting principle is also the same.
So I read the code of “MixVolume” and “SteamTurbineStodola”, which include volume connectors and flow connectors respectively, but I am not sure the difference between these two kinds of connectors.
My question is :
Could someone tell me the philosophy of using such two kinds of connectors in thermo-hydraulic systems, and in the code of every component, how should I deal with them so they work like they’re designed for.
Here is a very short and simplified explanation applying to thermo-hydraulic systems.
In flow models (pipes, valves etc.) enthalpy is unchanged and mass flow/pressure drop are related with a static equation.
In volume models pressure and enthalpy are dynamic state variables, that is, mass and energy conservation is "elastic".
As a rule of thumb, you should build thermo-hydraulic system models of alternating flow and volume models (in a staggered grid scheme) to decouple nonlinear systems.
For the dynamic pipe model in the top figure in your post the connectors merely indicate that, internally, the pipe model begins with a volume model and ends with a flow model.
Claytex has a nice blog post on the subject here https://www.claytex.com/blog/how-to-avoid-computationally-expensive-fluid-networks-in-dymola/
Also the authors of the Modelica Buildings Library have done a great effort explaining this in various papers. See e.g. https://buildings.lbl.gov/publications/simulation-speed-analysis-and
These kind of connectors are indeed the same due to modelica language specification. You can only connect two connectors that are interchangeable, that have the exact same amount and type of flow and potential variables. At every node all flows have to sum up to zero and all potentials have to be the same, therefore they have to be type consistent.
The difference is just information wise for the modeler or someone trying to understand the model and all components have been designed with such a thing in mind. It is easiest to understand with electrical components, where you have positive and negative pins which indicate in which direction the current should flow, but this is actually never really forced. Positive and negative pins are, ignoring their name, identical.
Although i don't know the connectors you are talking about i would assume that the VolumePort is a connector of something that has a volume and passes that information, whereas FlowPort passes the information about the mass flow rate. Usually a pipe i guess (?). Broken down to abstract dae theory one could say the names indicate if the potential or the flow variable are considered unknown for the component.
I have to emphasize that these are only indicators and that it is never actually forced by the model or the compiler. It is just how it should logically resolve in the end if you respect these restrictions of only connecting VolumePortto FlowPort connectors.
http://python.dronekit.io/develop/sitl_setup.html
there's a. mentioning that SITL is there for only a few pre-built vehicles. suppose i am designing a completely new model of flying vehicle, can i still simulate that?
Thanks a lot:) My drone design just has another set of mathematical expressions for its roll, pitch and yaw control. So, technically I need changes only in the AP_motors.cpp file (here the commands are converted into motor PWM values) only right? or is it more than that? Please guide me.
You can actually, but at this time there is no detailed documentation to do so. At the moment the best bet is by using RealFlight 8 to design the vehicle (and also to simulate the physics) and then use SITL to control it. You can check how to connect RealFlight to SITL at here http://ardupilot.org/dev/docs/sitl-with-realflight.html. There is also a discussion about building a custom model for RealFlight 8 with SITL at here https://discuss.ardupilot.org/t/building-realflight8-models/23106/34.
I know you can open an abstraction with the vis message, but I haven't found a way to present my abstractions in the patch containing the clone object. Perhaps dynamic patching is the only way to achieve this? I have searched the pd forum, mailing list and Facebook group without success.
Currently (as pd 0.48-1) there is no way of making the [clone] read the GOP of it's contents.
As a workaround you can encapsulate the [clone] object into an abstraction that provides a GUI that displays information about the selected clonede instance.
For example, let's say you have a Object called [HarmonicSeries] that, given an fundamental, it uses a [clone] object to create 8 instances of [Harmonic], each one containing a osc~ of the desired frequency. And you want to display the frequency of each Harmonic. Instead of using GOP on [Harmonic] you would use GOP on [HarmonicSeries] and provide an Interface to selected the desired harmonic to collect information.
The [harmonic] abstraction: it expects two parameters:
The fundamental frequency
The index of the harmonic
Then it multiplies both to get the harmonic's frequency and store it on an [float]. When it receives a bang it then outputs that frequency to it's left outlet.
[
Let's [clone] it and wrap it into the [HarmonicSeries] abstraction.
When the user clicks on the [hradio] to select the desired harmonic it sends a bang message to the correct harmonic, which in turn sends the stored frequency to it's outlet. It then displays the harmonic's index and the harmonic's frequency in number boxes.
Here's an example of it working (in the [HarmonicSeries-help] object)
This is a simple example but the principle is the same with complex cases. You encapsulate the [clone] into an abstraction that provides an interface for reading data from the cloned instances.
I am struggling with the question of what belongs in the Model in a MVVM architecture. Suppose I have an object called a Line which is made up of x,y data point pairs. I want to be able to add points to the line and I want to be able to do interpolation of points. For instance, I want to return a vector of y values when the user passes in a vector of x values. In order to do the interpolation I need the points in the Line object to be sorted in ascending x. Should the model just be the collection of Points? Does the model handle the sorting and interpolation or should a service handle this?
What should be in a model?
Short answer: The data
Longer answer:
The model represents the part of the application that is dedicated to data storage. So database access goes in the model. A good represention of that is a Repository-Pattern. (Which, in a more rigid interpretation of MVVM belongs to the service layer).
Your ViewModel holds the dynamic data. This means selection, ordering, locales, and so on.
A very good start on MVVM (and MVVM in action) is this video by Jason Dolinger. The sourcecode of the example can be found here
It is just one hour long, but i covers very good the aspects of MVVM and why it is that successful.