Path planning

As a student or practitioner in the field of operations research or logistics, I would like to understand the definitions of the terms used in equations (35)-(51) in the document. Specifically, I need clear definitions of the terms "front", "rear", "right", "left", "top", and "bottom" in the context of vehicle routing and logistics transportation. These definitions should be relevant to the scenarios described in the equations and help me understand how these terms are used in the process of assigning packages to trucks. Please provide a well-structured list or table with concise definitions for each term. If possible, provide actual examples or scenarios to illustrate how these terms are used in the given equations.