# Digital Twins in Software Engineering--A Systematic Literature Review and Vision
## 4 Results
### RQ3: How Can a DT Be Built in the Context of the Software Industry? There are attempts at standardization like ISO 23247 [210], mainly focused on manufacturing and other sectors, which include the IoT and M2M communication. Other remarkable attempts to standardize DTs are described by [PERSON] et al. [144]: (a) the Web of Things Description from the World Wide Web Consortium; (b) Digital Twin Definition Language by Microsoft; (c) Asset Administration Shell by Platform Industrie 4.0; (d) ETSI NSGI-LD; (e) PADI Connection Profiles; and (f) the Eclipse Ditto Platform. However, they are not specifically designed for creating DTs, and none of the mentioned ones has received widespread popularity to become DT standards. There is no consensus about which architecture, framework, or methodology is best for generating or creating DTs. [PERSON] et al. [127] summarize DTs and some areas of interest with different architectures. [PERSON] et al. [200] analyze the existing architectures for DTs--using the ISO 25010 [211] standard on software product quality as guidance--resulting in 56.42% of the architectural solutions being reference models. The analyzed solutions use a catalog of 10 architectural patterns, with half of the solutions focusing on two patterns specifically: layered and SOA patterns. The preferred approach is using a layered approach over a service-oriented one. [PERSON] et al. [201] review architectures with different numbers of layers. In many cases, a mechanism to generate DTs can be attractive to replace a digital or physical counterpart easily when a digital representation of the process, tools, and modelsis required during the system lifecycle in the context of PLM or ALM. In such cases, both systems, the DT and the counterpart, are executed simultaneously and should be managed and synchronized. [PERSON] et al. [6] theorize about the possibility of generating DTs for PLM/ALM using Open Services for Lifecycle Collaboration (OSLC) [212]. OSLC provides a standard interface for interoperability between different software tools and systems throughout product development and lifecycle management. In contrast, [PERSON] et al. [205] center their analysis on specific architectural patterns to apply DTs for different lifecycle stages, such as the conception, development, production, utilization, support, and retirement stages. The catalog is composed of nine architectural patterns: (a) the digital model, digital generator, digital shadow for concept, development, and production stages; (b) the digital matching, digital restoration, digital monitoring, digital control, and digital autonomy for utilization and support stages; and, (c) the digital proxy for utilization, support, and retirement stages. From an ALM perspective, three pillars define the infrastructure in the software industry: governance, development, and operations [112], as well as, more recently, security. In this context, DTs can be generated to have a digital replica of tools and processes currently managed in an organization. An infrastructure architecture based on the digital control pattern can assist the construction of DTs. From a connectivity perspective, DTs can cooperate in a system of systems (SoS) approach, as reflected in the architecture. This is similar to [PERSON] et al. [144]. In this way, the four critical capabilities for enabling DTs for manufacturing described by [PERSON] [213] can be covered:  
* Digital modeling: DTs must be capable of generating virtual models. * Analytics support: DTs should provide services to understand anomalies more precisely and the relationships between the anomalies and the whole value chain. * Timeliness update: DTs must be able to update the virtual models and data storage platform in near-real time, parallel to the asset system's operation. * Control: DTs must supply the capacity to autonomously take action to control the assets based on conducted analyses from a process perspective and product operation.