# Cyber-Social Systems: Modeling, Inference, and Optimal Design

## TL;DR

This paper introduces a new distributed inference protocol for cyber-social systems, analyzes agent classification and network connectivity requirements, and proposes polynomial solutions for cost-optimal network design under observability constraints.

## Contribution

It presents a novel inference protocol that works without rank assumptions, classifies agents based on connectivity needs, and offers polynomial solutions for cost-efficient network design.

## Key findings

- New distributed inference protocol applicable to low-rank systems
- Agent classification based on cyber-network connectivity requirements
- Polynomial solutions for sensing and networking cost optimization

## Abstract

This paper models the cyber-social system as a cyber-network of agents monitoring states of individuals in a social network. The state of each individual is represented by a social node and the interactions among individuals are represented by a social link. In the cyber-network each node represents an agent and the links represent information sharing among agents. Agents make an observation of social states and perform distributed inference. In this direction, the contribution of this work is threefold: (i) A novel distributed inference protocol is proposed that makes no assumption on the rank of the underlying social system. This is significant as most protocols in the literature only work on full-rank systems. (ii) A novel agent classification is developed, where it is shown that connectivity requirement on the cyber-network differs for each type. This is particularly important in finding the minimal number of observations and minimal connectivity of the cyber-network as the next contribution. (iii) The cost-optimal design of cyber-network constraint with distributed observability is addressed. This problem is subdivided into sensing cost optimization and networking cost optimization where both are claimed to be NP-hard. We solve both problems for certain types of social networks and find polynomial-order solutions.