# Systems Engineering Methodology for Designing Digital Public-Private Partnership Platforms
## 1 Introduction  
The past decades have been marked by the implementation of a huge number of large-scale investment projects in the field of industrial and social infrastructure in the macro-regions of the world and individual countries. The population of many countries and regions is experiencing a serious lack of infrastructure objects, which are either nonexistent, worn out, or requiring urgent repairs and restoration, as well as the creation of new ones. The serious losses from the infrastructure deficit are also borne by society as a whole, for whom the problems of renewing existing infrastructure and finding sources for its financing have become very acute. The experience of many countries has demonstrated that tax revenues alone are unable to solve these problems in infrastructure provision.  
The state, while acknowledging the importance of developing and implementing such policies, often has limited budgetary resources and a lack of professional staff for carrying out major infrastructure projects. Private business is also not ready to invest in infrastructure projects due to high risks and long payback period, and uncertainty of the result in the future. A solution could be to pool the resources and capabilities of the state and the private sector through the public-private partnership (PPP) mechanism.  
At the same time, it is important to note the problems in the implementation of PPP projects. In particular, these include increases in the complexity and duration of theproject [1], the lack of risk-sharing, and conflicts of interest between participants, as well as the complex mechanism of tenders [2]. To simplify the interactions between the project participants, this article proposes to develop a digital platform uniting customers and suppliers of goods and services.  
The development of such a platform also raises a number of questions: how to attract participants and thus increase the value of the platform [3; 4], how, in the future, the platform will expand and what processes will be transferred to the external environment [5], which participants will form the core of the digital platform (DP) and its ecosystem [6]. The solution to these problems is directly dependent on the interests of stakeholders and future participants of the platform being designed.  
The goal of this study is to form proposals on the development of a digital platform for PPP, taking into account the interests of the parties involved. The systems engineering (SE) methodology is used for the task as the basis for developing complex systems that meet the set of requirements of many interested parties [7]. Working with interested parties is especially important during the early stages of design. In systems engineering, there are a number of practices for working with stakeholders [7]. They allow us to form a detailed concept of a complicated system [8], which includes the DP.  
To reach the set goal, the authors of this work identified the following tasks:  
* Identify and analyze the current problems and shortcomings of PPP mechanisms;
* Provide an analysis of the concepts of the DP and form a definition of a DP for PPP;
* Develop a framework for implementing a DP for PPP based on the SE practices;
* Define a range of interested parties engaging in the implementation of joint projects using SE practices to revealing stakeholders and their needs;
* Reveal and present the key interests of stakeholders in a PPP on diagrams;
* Determine the challenges for further research work.  
The results obtained will provide the basis for the subsequent development of functional-logical architecture and physical embodiment of the DP.