Meetup 22 Resources

Meetups/22/2024-11-18-minutes.md

@@ -0,0 +1,142 @@
+# Meeting Minutes
+
+## Info
+
+:date: **Date:** 18 November 2024
+
+### :bust_in_silhouette: Participants
+
+- Ege Korkan
+- Cristiano Aguzzi
+- Luca Barbato
+- Vignesh Vaidyanathan
+- Anna Schmidt
+- Dr. Pasha Shabalin
+- Simone Tassi
+- Kunihiko Toumura
+- Jadyn D'mello
+- Daniel Peintner
+- Michael Koster
+- Richard Bowman
+- Oscar Juina
+- Lorenzo Gigli
+- Richard Kuntschke
+
+## Meetup
+
+### Introduction
+
+Ege: Welcome to the 22nd meetup!
+
+### News
+
+Cris: the week after we will have WoT week a physical event dedicated to WoT.
+Cris: We have office hours
+Cris: let us know if you want to present something!
+
+#### WoT Week
+
+Cris: We will see each other from 25-29 November in Munich. Two venues, Siemens and Microsoft.
+
+Cris: During the event we will host a Plugfest event an interoperability hackathon!
+
+Cris: Wednesday it is demo time, you can show your WoT solution.
+
+Cris: let us know if you want to join!
+
+### Meetup Presentation
+
+Vignesh: I work at CALA. We accelerate lasers to measure ions. It is remotely controlled due to high power laser or radiation.
+
+Vignesh: You can measure the pulse or the cross section. Which allows you to get physical characteristics. So there are data analysis steps as well.
+
+Vignesh: Data acquisition is IoT in the end.
+
+Vignesh: High power lasers by stretching, reducing the frequency and then amplifying. In the end, it is compressed, where you get a high power pulse.
+
+Vignesh: All these steps use custom built components. The whole setup cannot be bought.
+
+> Vignesh shows the UI with different cameras and controls.
+
+Vignesh: Here we can use WoT to work with the integration time value in the UI.
+
+Vignesh: When we look at the devices, e.g. an oscilloscope, it has properties like time resolution. Actions like start acquisition. Events like measurement points.
+
+Vignesh: However, those devices also have state machines. When a measurement is happening, you cannot the trigger value of a camera. 1 out of 4 cameras can do that.
+
+> Vignesh shows the code part of Hololinked
+
+Vignesh: from the code, we can autogenerate the TD.
+
+> Vignesh shows property, action and event generation.
+
+Vignesh: We can add state information. You can tell if an action is allowed in a state or not.
+
+Vignesh: This is also reflected in the UI.
+
+Vignesh: One important thing is to correlate the timing of different measurements.
+
+Vignesh: Another part is how we can synchronize GUIs. Say, one user starts measurement from one PC.
+
+Vignesh: GUI information about the state is also very important and it is device specific. So we can notify the other clients about state changes.
+
+Vignesh: You can use the context API of frameworks like React or Svelte.
+
+Vignesh: That is it for today. I can get questions now.
+
+### Question
+
+Cris: Is the last event implementation built on top of MQTT?
+
+Vignesh: It is on ZMQ. You don't have to define multiple socket. Messaging contract is different.
+
+Vignesh: We don't have a ZMQ binding though. It is interesting and the WebThing Protocol can be used by over ZMQ.
+
+Vignesh: Images need to be a separate frame though.
+
+Cris: What if you encode the image in JSON with base64 then you don't need another frame.
+
+Vignesh: I also could not get nice image manipulation in JS so I use the python qt for that.
+
+Richard: How do you handle big arrays like numpy?
+
+Vignesh: You can pre-encode it in zeromq. You can dump the memory on the message quite easily.
+
+Richard: Is there a standard way in msgpack (or JSON or whatever) to serialize a big numeric array? I'm wondering if there's something that's not numpy-specific?
+
+Vignesh: Python's own parser was much more performant than numpy. C++ and JSON.
+
+Ege: How is the state information conveyed to the Consumer?
+
+Vignesh: there is a property but the machine itself is in my head. I hope that the standards can help.
+
+Cris: You can also show different TDs per state, as long as there aren't so many states
+
+Vignesh: I also do a lot of time-critical processing. Like 1ms time intervals are important.
+
+Richard: I'm also curious how "dynamic" a thing description is allowed to be - I've sometimes assumed I can parse it once when I set up my client then assume it won't change: is that a bad idea?
+
+Cris: there are some use cases to ask for dynamic TDs but they are not that developed yet. So you are doing correctly.
+
+Ege: What does it mean to delete a property btw?
+
+Vignesh: I want to free up the memory. I can either write an empty array or send a DELETE request.
+
+Ege: So it is more like resetting
+
+Cris: Or clearing.
+
+Vignesh: I also fire a property update when there is a write.
+
+Ege: How do you do async actions?
+
+Vignesh: You can add `synchronous:False` which starts a thread but you cannot do anything with that thread.
+
+Ege: Maybe you can combine the devices you are bringing with the openflexure microscope we have.
+
+Richard: It would cool to test if the UI can control the microscope backend. I also have a new implementation that is almost ready. You can use a new OS image.
+
+## :envelope_with_arrow: Feedbacks
+
+- State machine modeling is missing.
+- Long running actions is done differently between two implementations (hololinked vs openflexure)

Meetups/Readme.md

@@ -5,6 +5,16 @@ This readme contains the links to minutes, presentation files and the recordings
 
 Note: Presentation files use the pattern `YEAR-MONTH-WoTCG-EVENTNAME-PRESENTERNAME.FILETYPE`.
 
+## Meetup 22
+
+- Name: Scientific Instrumentation and Control with WoT
+- Presenter(s): Vignesh Venkata Subramanian
+- Date: 18 November 2024
+- [Presenter Slides](./22/2024-11-WoTCG-Meetup22-Scientific_Instrumentation-CALA.pdf)
+- Intro Slides: [Google Slides](https://docs.google.com/presentation/d/1ZorsPNGiC3qEeLarrggwyB6G3rgmRz42_vEz5s8icq8/edit?usp=sharing) | [PDF](./22/2024-11-WoTCG-Meetup22-AguzziKorkan.pdf)
+- [Video](https://youtu.be/k2KMKd2ZVq0)
+- [Minutes](./22/2024-11-18-minutes.md)
+
 ## Meetup 21
 
 - Name: Web of Things for every thing