fjage | Framework for Java and Groovy Agents | Runtime Evironment library

I am writing a simulation script which involves 2-UUV and 1-USV. Both Underwater vehicle doing surveying in orthogonal lawnmower motion model. I would like to stay in the range of both vehicle, so they started at the same origin point. I want to know that How can define USV motion model in such a way that it is always in the communication range of both UUV's for most of the time.

1. Basically How can I manually provide dynamic path planning/ motion model to USV so that I can communicate to both UUV most of the time ? Is it even possible ? Could someone provide a basic example of this or point me in the right direction ?

Here is my simulation script :

I have implemented a localization algorithm with 4 nodes topology and it is working fine but in the log file I am getting this error and I am not able to understand where the problem is. The algorithm gets stuck for sometime and this error appears and after that it again resumes the normal flow.how to remove this error ?

I was wondering what did the Unetstack agent expect as a response to a TCP connection which is established to the modem at ip:port ?

I was trying to connect to the the modem using the TCP connection through the GNURadio pdu socket. The connection was established but i think after handshaking, it was automatically terminated. Did it expect something ?I am planning to send custom messages to modem using this APIs.

Here is what i have done so far.

1. I opened a TCP connection using Socket PDU block using below flow graph.

1. I used unet audio SDOAM to test:

I am trying to get coordinates from the neighbouring nodes using a broadcast request and store them into lists. I am able to get only one of the responses and I think this happened because of collision between the responses as the nodes have responded at the same time. I have tried to use the Backoff Behavior with random backoff on the agent of neighbouring node but it didn't solved the problem. How can I sync the mechanism to avoid the collision ? I have written an agent for each blind node (which will make the broadcast request) and the neighbouring nodes.

Following are the code snippets.

Agent on blind node:

In the startup method of my agent I get the agent ID of the physical agent as:
phy = agentForService(Services.PHYSICAL)

Then I have tried different ways to set the powerLevel but usually something like:
phy.send(new ParameterReq().set(PhysicalChannelParam.powerLevel, -20))
phy.send(new ParameterReq().set(PhysicalChannelParam.powerLevel, [-20 -20 -20])) phy.set(PhysicalChannelParam.powerLevel, [-20 -20 -20]

Neither of them works.
I guess this is because there are multiple physical channels (CONTROL, DATA).
How do I specify which channel type to change the power level of?

EDIT:
A solution was to apparently to change the parameter directly:
control_channel = phy[1]
control_channel.powerLevel = -20
However, this feels like violating the basic ideas behind Fjåge.

How can i use the existing modems which is not subnero with UnetStack (basically is not support UnetStack natively) ? I was gone through the post in detailed, but unfortunately had bad compilation issues. Can anyone point me to right direction ?

Below is the detailed error i encountered:

I'm trying to use the JsonTypeAdapter in a modem to transmit some data from a remote source. The adapter is enabled through the modems startup script (JsonAdapter.enable()), and a TCP connection is established to the modem at port 1100. I follow the "Hello world" example in the Fjåge documentation and send the following JSON to the modem:

{"action":"send","message":{"clazz":"org.arl.unet.DatagramReq","data":{"data":{"clazz":"[B","data":"aGVsbG8gd29ybGQh"},"msgID":"8152310b-155d-4303-9621-c610e036b373","perf":"REQUEST","recipient":"phy","sender":"MyCustomInterface"}}}

I've set the logLevel to 'ALL' and can see that I get an incoming TCP connection in the log, but no data is being transmitted by the modem. I'm subscribing to the physical agent but am not getting any notifications in the WebShell (using UnetSocket works fine though).

I'm guessing that either the JsonAdapter isn't active on this TCP connection, the JSON string is faulty or not being sent properly by my application, or something else that I've missed.

I am trying to make a link between a Python script and a simulation running on UnetSim. I want to send messages from Python and receive them in UnetStack using a Python_Agent.groovy that I created and added to container of each node in the simulation. I also want to do the reverse.

I used the fjage documentation (https://buildmedia.readthedocs.org/media/pdf/fjage/dev/fjage.pdf) to help me. The problem is that in gateway class Services there is not the PYTHON_AGENT Service that I created. I can understand that as my enum Services does not modified class Services where there are NODE_INFO, PHYSICAL etc... My question is then how the example in the documentation 1.6.3 works ? And is it applicable to my case ?

Here is my code :

PythonSocketExample.py