# Towards a Reference Architecture for Cargo Ports
###### Abstract  
Cyber-Physical Systems (CPS) are physical systems whose operations are coordinated, monitored, and controlled by computing and communication functions. These systems are typically heterogeneous, including Internet of Things and information technology subsystems, and can present a myriad of implementation details, making them very complex systems. An important type of CPS is a maritime container terminal (cargo port), which is a facility where cargo containers are transported between ships and land vehicles for onward transportation and vice versa. A cargo port performs four basic functions: receiving, storing, staging, and loading for both import and export containers. We present here process patterns that describe the functional aspects of cargo ports and a pattern that describes their structural properties (patterns are encapsulated solutions to recurrent problems). These patterns describe semantic aspects found in any cargo port and can be adapted to describe other CPSs. We decompose these process patterns into use cases that describe their interactions with the system. We then integrate the process patterns with structural patterns to assemble a partial reference architecture (RA) that shows the interactions of all the patterns while also indicating the typical stakeholders found in all ports. We validate the proposed reference architecture, highlighting its theoretical and practical value. Software and system designers of cargo ports need to start from a conceptual and abstract view that is subsequently refined to add more details. The use of reference architectures and patterns is an effective way to organize and describe the functional and non-functional aspects of a system, as well as to unify the design of all its aspects. This is, until now, the only published RA for cargo ports, and it can be a useful guideline for the designers of any type of cargo port. m 2023 15  
and real-time operating systems, as well as products from different vendors using different protocols. Many CPS also need to follow government or industrial regulations [3]. The design of CPS systems requires consideration of several disciplines, such as embedded systems, computers, communications, and others, and the software is embedded in devices whose principal function is not only computation. However, we are concerned here only with software aspects that are pervasive in modern systems. CPSs can be very complex systems and may comprise a multitude of systems, components, and implementations; they can be classified as massively interconnected, complicated systems [4]. To be able to understand their interactions and perform their design, we need to consider their global architectures and apply abstraction, focusing on their fundamental properties. A reference architecture (RA) is a generic software architecture, based on one or more domains, that does not include implementation details [5; 6]. An RA is reusable, extensible, and configurable; it also provides guidelines for interoperability and portability. RAs can be seen as patterns for complete architectures and can be instantiated into concrete software architectures by adding platform aspects [5]. A software pattern is an encapsulated solution to a recurrent software problem and defines a vocabulary that concisely expresses requirements and solutions, as well as provides a communication vocabulary for the involved stakeholders [7; 8]. A reference architecture built using patterns is a useful way for designers to describe the system and analyze security and other non-functional aspects. Specifically, for CPSs, these abstraction artifacts have become not only very useful to understand and building these complex systems but also have the potential to unify the design of the computational, communication, and control aspects of CPSs, especially in the presence of the many implementation details of their component units. There are many types of CPSs, such as those in aerospace, automotive, chemical processes, healthcare, manufacturing, and transportation.