# Distributed Ledger Technology for Smart Mobility: Variable Delay Models

## TL;DR

This paper develops a fluid-based mathematical model for DAG-based distributed ledgers in smart mobility, incorporating variable transaction delays, and validates it through extensive simulations to support feedback control applications.

## Contribution

It introduces a novel fluid approximation model for DAG-based DLTs with variable delays, extending prior work and aiding in control system integration.

## Key findings

- Model accurately predicts DAG behavior with variable delays
- Simulations confirm the model's effectiveness for feedback control
- Enhances understanding of DLT dynamics in smart mobility

## Abstract

Recently, Directed Acyclic Graph (DAG) based Distributed Ledgers have been proposed for various applications in the smart mobility domain [1]. While many application studies have been described in the literature, an open problem in the DLT community concerns the lack of mathematical models describing their behaviour, and their validation. Building on a previous work in [1], we present, in this paper, a fluid based approximation for the IOTA Foundation DAG based DLT that incorporates varying transaction delays. This extension, namely the inclusion of varying delays, is important for feedback control applications (such as transactive control [2]). Extensive simulations are presented to illustrate the efficacy of our approach.