Measure efficiency

[mahya s]

Hi,

I have a network with 45 nodes. I want to remove one node and then measure the efficiency of the network. Does anyone know how I can measure it? Thanks!

[Kathleen Carley]

there are many measures of network efficiency - including graph centralization - and accuracy - both are in the report

Run under dynamics the immediate impact report, remove the node of interest and then see the change in the network - many of these measures get at different aspects of efficiency

On Sun, Apr 23, 2023 at 4:59 PM mahya s <sam.m...@gmail.com> wrote:

Hi,

I have a network with 45 nodes. I want to remove one node and then measure the efficiency of the network. Does anyone know how I can measure it? Thanks!

--
Computational Analysis of Social and Organizational Systems (CASOS)
The Institute for Software Research, Department of Computer Science
Carnegie Mellon University, Pittsburgh, PA, USA
http://casos.cs.cmu.edu/
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[Mihovil Bartulović]

Hi,

If you are referring to the efficiency of a network as "the degree to which each component in a network contains the minimum links necessary to keep it connected," there are several ways to obtain that information in ORA.

1.  If you use the Simmelian Ties Analysis report, you can find the Efficiency value within the report. Then, you can remove a node and run the same report again to see the difference between the two networks.

More 'hacky" way but nicer visualization way:

2.  Create a copy of your network within ORA by selecting your network in the Meta Network Manager, then pressing CTRL + drag and drop to create a copy, or pressing CTRL + C followed by CTRL + V.

      Select the original network and in the Meta Network Editor, you will see the Meta Network Time section. Press on Period and add the value 1 to it.

      Select the copy of the network and in the Meta Network Editor, under the Meta Network Time section, press on Period and add the value 2 to it.

      Expand the copy of the network, select your nodeset, and remove one node for your analysis (select the node under the Editor tab -> Nodes -> Delete Selected Nodes).

      Select both meta networks in your Meta Network Manager -> right click on them -> Create a Dynamic Meta-Network -> Run

      Select your new dynamic meta network -> Measure Charts -> Make sure only your dynamic meta network is selected -> Next -> Run

      In the new window under network level -> add measure -> efficiency and ORA will make you a graphic how network efficiency changes with node removed.

Another way to assess efficiency and the impact of node removal is by looking at the Modularity Vitality metric of the original network. This will give you an idea of which nodes are more important to the network in terms of creating communities and clusters. To obtain this metric, simply select your original meta network, go to Measure Charts, select All Measures, click Compute, then click Next. Under Bar Chart, select "modularity vitality bridge" or "modularity vitality hub" (one shows nodes that are bridges in networks, the other shows nodes that are more hub-like in your network).

Hope this helps!

[Mihovil Bartulović]

As Dr. Carley mentioned, there are plenty of ways to assess the efficiency of the network. The second "hacky" procedure will give you the visualization original + node removed network, regardless of the efficiency metric(s) you select for your analysis.

[mahya s]

Thank you so much for your help. I tried the "hacky" way that you mentioned, but the problem is when I need to add the value to the period, there is not any "period" tab. Please see the screenshot below.

Appreciate your help.

[Mihovil Bartulović]

My best guess is that it's due to the fact that you're using an older version of ORA. The newest version is v3.0.9.154, while you have v2.3.2.

The 'Period' allows you to set times like 0 or 1, so the x-axis of the plot shows 0 -> 1. However, you can just pick two different dates, for example Jan 1 and Jan 2, and as long as you know which one is which, you'll have the exact same visualization aside from your x-axis having selected dates as labels

[mahya s]

Thanks again for your response. Using your suggestion, I reached this point (please see the attached screenshot), showing me different measures.

Actually, my meta-network includes several agents, tasks, resources, and knowledge. I would like to remove each node and measure the efficiency of the new meta-networks based on the percentage of tasks that can be completed by the agents assigned to them (i.e., based on whether the agents have the requisite knowledge and resources to do the tasks). Task completion percentage is assessed from knowledge-based and resource-based perspectives, respectively.

Could you please let me know which measure I can use or how I can do this?

Thanks

[Mihovil Bartulović]

There is no such network level metric in ORA (or in network science) but there is a way to do what you need

1. For the analysis you described, you would need to have an Agent x Task network within your meta network (as well as Agent x Knowledge, respectively).

2. Right-click on your Agent x Task (or Knowledge) network and select "Fold Network" from the drop-down menu. Choose either row or column folding, depending on whether you have Agent x Task or Task x Agent in your original network, but the output will be the same.

The folded network is a projection of your bi-modal network (Agent x Task) to a uni-modal plane (Task x Task), and the link values tell you how many agents can complete a certain task.

3. If you look at your new network, the diagonal will give you information regarding how many agents can perform a certain task or have certain knowledge. The elements that are not on the diagonal, i.e., the weight of Task1, Task2, etc., give you the number of agents that can perform both tasks.

4. Now, you can either create a copy of your network or work with the original one. Either way, you will need to expand your meta network, select your Agent nodeset, and in the editor tab, select the agent you wish to delete. Then, go to Nodes -> Delete Selected Nodes. Afterward, you can repeat steps 1-3 and fold the new networks again with the Agent(s) deleted. You'll need to name the folded network something else, as the same meta network cannot have two networks with the exact same name.

5. Compare the results between two folded networks to see how removing an agent impacts your Tasks/Knowledge
   

Hope this helps!

[mahya s]

Thank you so much for your help. I found some measures based on your previous information. Just one more thing that I cannot find. Overall, I need to measure: 1-"Task completion knowledge based" and 2- "Task completion resource base".

I found the first one, please see the screenshot (1) in attachment. But I cannot find the second one. I even go through the "custom measure" and found it and select visible (see screenshot (2)), but when coming back to the list of measures, again cannot find the "Task completion resource based".

[Mihovil Bartulović]

I think that depends on what networks are available to ORA. To the best of my knowledge, ORA allows you to create all the possible measures given what is available in the meta network manager.

It's hard to say why the other measure is not there without having the data for me to test. It could be an issue of the v2.3.2 of ORA, but I can't say for certain

[mahya s]

Thanks again. Is it possible that I can share my meta-network with you to check what is the problem? ( I attached it here if it's possible for you).

Thanks again.

[Mihovil Bartulović]

I played around with your data removing random nodes to see how the task completion percentage will change.

ORA doesn't have the other measures as far as I can remember. Maybe Jeff or Jon will know - I'll ping them

I tried the folding method I mentioned earlier :  Task x Agent folded into Task x Task - shared Agent for original network and the one with Agent removed. On the main diagonal I saw a change in number of available agents to do a certain task i.e. coordinating the application of the robot went from having 2 agents being able to do it to 1

[Kathleen Carley]

• the task completion measures should be in the management report

--

Computational Analysis of Social and Organizational Systems (CASOS)
The Institute for Software Research, Department of Computer Science
Carnegie Mellon University, Pittsburgh, PA, USA
http://casos.cs.cmu.edu/
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[mahya s]

Thank you all for your reply.

To Dr. Bartulovic: what do you mean by "main diagonal"? how can I access that?

To Dr. Carley: Where is the management report? I see all three task completion measures "knowledge-based, resource-based, and overall" and check the marks to be visible, but I couldn't find them when applying the measure.

[Mihovil Bartulović]

If you click on the folded network in the meta network manager (i.e. Task x Task - Shared Agent) -> on the right hand side press on the Editor tab and there you can see the matrix that represents the network.

The diagonal of this matrix tells  you how many agents can do a certain task in your scenario. Removing an agent that knows how to do "taping drywall joints" will make the decrease the value at (taping drywall joints,taping drywall joints) by 1

[mahya s]

Thank you, I got it.