# 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?
In this case, the Facebook www platform can map users' relationships and social interactions. * Ethics and review on decision making from algorithms and automatic processes. This is linked to auditing purposes. [PERSON] et al. (2017) propose the application of ethical DTs to artificial intelligence (AI) to evaluate transparency, trustworthiness, and bias in decisions. Similarly, [PERSON] (2019) follows the same approach of using DTs to verify decision making under uncertainty. Likewise, [PERSON] et al. (2012) use DTs as intelligent agents to assess the runtime behavior of real system components. Furthermore, [PERSON] et al. (2015) also propose a framework to build and test DTs to transparently verify their expected behaviors in their early development stages and validate their effectiveness. Evaluating the reasons covered by the analyzed works in Table 4 to include or manage DTs in the software industry, the weight of importance of each area can be determined according to the percentage of works found for each target. Thus, Figure 2 graphically shows the percentage of each area. According to it, areas 1 and 2 capitalize 64% of the importance of using DT in the software industry. That is, the fundamental reasons are focused on mitigating the complexity of software and improving the analysis, design, prognosis, planning, and rapid response to the software development process. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Area** & **Articles** & **References** \\ \hline Analysis, design, prognosis, planning, & 26 & [87,125,126,129,131,134,136,145,149,150,158,165,168, \\ and rapid response & 26 & 169,174,176,178,180,181,182,183,184,185,186,168, \\ \hline Replicate cognitive capabilities & 3 & [141,142,189] \\ \hline Complexity and level of abstraction demand & 21 & [114,115,121,131,135,137,141,152,153,156,159,160,162, \\ automation, efficiency, and simulation capabilities & 163,175,177,190,191,192,200] \\ \hline Ethics and review of decision making of & 9 & [  
For our study, we consider the above five reasons an excellent fit to justify DTs within ALM. They all cover vital aspects of the three main ALM areas: governance, development, and operations. As DTs can mitigate risks and reduce costs--including cybersecurity critical issues--this also would impact the sustainability of the software industry. DTs can cope with the claim pursued by digital transformation in which all software development and management processes should be digitized and automated. To demonstrate the possible connection, the popularity of the term \"Digital Twin\" in the last five years in a side-by-side comparison with the digital transformation concept using Google Trends was analyzed in Figure 3. Digital transformation enables the creation and use of DTs regarding advanced technology, skills, and culture. On the other hand, the DTs help to create a digital representation of the physical model to offer advanced capabilities. Consequently, it makes sense to see certain similarities in the evolution of both terms. By default, it is impossible to carry out ALM using a single tool for project management. ALM covers the SDLC, and the potential ecosystem of toolsets with different vendors is enormous. Finding time to understand the correlation between the changes and outcomes throughout the whole ALM in real time and how to make the flow more efficient is somewhat problematic. The value stream mapping technique aims to explore the flow offline and identify where the waste is to optimize it. DT technology aims to create digital capabilities that synthesize the critical areas of the flow in real time to enable automatic optimizations. We consider DTs a consequence of digital transformation to support a growing complexity value stream with a good balance of speed to release new features and deliver products to the market. As remarked, the smart manufacturing area is an excellent place to extract findings.