NPTEL Social Networks Week 10 Assignment Answers 2025
1. In a growing scale-free network, the probability that a new node connects to an existing node i
is proportional to:
- The square of the node’s current degree
- The reciprocal of the node’s current degree
- The logarithm of the node’s current degree
- The node’s current degree
Answer :- For Answers Click Here
2. In a preferential attachment model, what happens to the degree distribution as the network grows?
- It follows a power-law distribution where few nodes have extremely high degrees.
- It approaches a normal distribution with most nodes having a similar degree.
- The network stabilizes with a fixed number of high-degree nodes.
- The degree distribution converges to a Poisson distribution.
Answer :-
3. In a random network, disease spread follows a classic percolation model. What additional factor makes epidemic spreading in a scale-free network more dangerous?
- The presence of hubs that accelerate disease transmission.
- The clustering coefficient is higher, preventing transmission.
- Scale-free networks have a fixed diameter, limiting the spread.
- The degree distribution follows a Poisson distribution, reducing risk.
Answer :-
4. How does network structure affect the basic reproductive number (R0) of an epidemic?
- In scale-free networks, (R0) is highly variable due to heterogeneous degree distribution.
- In random networks, (R0) is always greater than 1.
- In lattice-based networks, (R0) is exponentially high due to structured connectivity.
- Network structure has no effect on (R0).
Answer :-
5. If an epidemic spreads faster than expected in a scale-free network, which intervention strategy is most effective?
- Randomly vaccinating 50% of the population
- Isolating nodes with high clustering coefficient
- Targeted vaccination of high-degree nodes (hubs)
- Reducing the number of edges per node uniformly
Answer :- For Answers Click Here
6. The key reason why an SIR model behaves differently from an SIS model in networks is:
- SIR models assume no reinfection, while SIS allows reinfection.
- SIS models lead to disease eradication, while SIR does not.
- SIR models require a fixed network topology, while SIS does not.
- In SIS models, the disease persists indefinitely, even if R0 < 1.
Answer :-
7. In the percolation model of epidemics, what does the percolation threshold represent?
- The fraction of removed edges needed to prevent an epidemic.
- The time taken for the entire network to be infected.
- The fraction of nodes vaccinated before herd immunity occurs.
- The degree distribution required to sustain an epidemic.
Answer :-
8. When analyzing network robustness, which strategy best describes the difference between random node failure and targeted node attack?
- Scale-free networks remain robust under random failures but collapse under targeted attacks.
- Scale-free networks collapse equally under random and targeted attacks.
- Removing low-degree nodes has the same impact as removing hubs.
- Random node failures and targeted attacks follow identical percolation dynamics.
Answer :-
9.
Answer :-
10. Which network type is most resistant to an epidemic spreading?
- Scale-free networks
- Random graphs
- Lattice-based networks
- Small-world networks
Answer :- For Answers Click Here
