# Digital Twins in Software Engineering--A Systematic Literature Review and Vision
## 4 Results
### RQ2: Is a DT Necessary for SDLM and ALM in the Software Industry? [PERSON] and [PERSON] (2007) stated on the vision of autonomic computing based on the 2001 IBM manifesto that due to the complexity of modern systems, they need to be self-managed. DTs were usually adopted in areas unrelated to software development, such as manufacturing, construction, mechanical engineering, and health. In these areas, DTs became powerful tools to tackle complexity, substituting or enhancing expensive steps with a digital counterpart capable of improving the process involved with a reduction in the overall cost and risk on the system. From the publications analyzed, five main reasons are identified by authors to sustain an investment in DTs. These reasons define the main areas in the software industry where DTs can have a positive impact:  
1. The complexity of current systems: The complexity of the SDLC requires simulation capabilities for the automation efficiency that is needed for the continuous improvement of aspects of the value stream and the product. [PERSON] et al. (1990) use virtual infrastructure DTs to help with the complexity of complex workflow ecosystems. In contrast, [PERSON] et al. (2014) highlight the need for appropriate methods and tools to enable continuous and accurate assessments of the quality of system architectures so that it is not a siloed territory based on the expertise of a few engineers. Also, [PERSON] (2015) observes that the complexity of software process management grows as the number of related decisions increases, offering a potential framework to tackle this complexity during software processes. Having expertise in all the areas of the lifecycle of products is quite complex and requires enough resources with a level of infrequent expertise to cover all needs. [PERSON] et al. (2015) comment on the need to rethink the interplay between human-computer interactions and software engineering for a rapid response to the evolution of technologies. It also set the DT as a protagonist of the digital transformation process. 2. Analysis, design, prognosis, planning, and rapid response, even for heterogeneous vendors: DTs can adaptively monitor operations and value streams and improve reaction times. For instance, [PERSON] (2015) explores combining process mining techniques with model-driven DTs to efficiently combine data and models at runtimes applied to conformance-checking techniques. [PERSON] et al. (2015) speak about smart troubleshooting to analyze information from various sources and find relationships with troubleshooting instructions and software fixes. The whole product cycle is suggested to be covered by [PERSON] et al. (2018) and [PERSON] et al. (2018) with an approach inspired by DevOps. [PERSON] et al. (2016) present the creation of an agile digital platform to facilitate the orchestration of complex workflows to identify risks in the design process. The benefits of applying DTs in different use cases can be appreciated in this paragraph. Planning the prioritization of these US resources also requires a methodology, as exposed by [PERSON] et al. (2018), that helps give a response to business objectives and challenges. 3. Knowledge sharing to improve collaborative processes: DTs help to support engineering by reinforcing knowledge-sharing practices and maintaining information isolation, transparency, and evolution tracking on the product side. [PERSON] (2016) applies DTs to mitigate the risk of poorly documented architectures and again discusses the complexity of the software development process. 4. Replication of human skills: Some recent works propose the development of DTs linked to replicating human profiles. This area could grow significantly by including massive trends, such as LLM (large language model) systems like ChatGPT. In this way, [PERSON] et al. (2014) comment on cognitive DTs to turn users' data into a future DT of users, while [PERSON] et al. explore (2014) the simulation of a cyber entity rather than the traditional approach of mirroring a physical entity.