Operations routing and scheduling problem: Concept, graphing and notation systems

Abstract

Operational demands drive operators, machines, and objects to undertake time–space transfers and execute tasks to optimize system objectives in various engineering, manufacturing, and service scenarios such as prefabricated construction, roadbed construction, open-pit mining, pipe casting, steel processing, IT maintenance, airport shuttle service, and community virus elimination service. Establishing a unified concept model framework for the operations routing and scheduling problem by generalizing the characteristics of the problems portrayed by research in various fields, not only integrates research in multiple fields and connects the methods, but also provides a systematic and in-depth portrayal of the elemental structure of the problem. This unification enhances understanding of related research and forms a synergy in the field.

This paper explores the establishment of a unified modeling framework for the problem, using a concept system based on elemental analysis, a graphing system based on time–space network, a problem taxonomy and a notation system. The elements in the problem, including the operators, operation machines, operation objects, operation time–space, and operation relations, are analyzed. A unified graphing system is designed for each element and scenario to organize in a time–space network diagram, including a time–space transfer diagram, a operation space diagram, and an operation network diagram. Based on the type, quantity, function, and structure of each element, a taxonomy and a four-domain notation system for the problem are established. The unified modeling framework is then applied to describe eight typical scenarios, demonstrating its wide applicability.