## 2 Literature Review and Cost Estimation Methods
### Coestim--Design Simulator for Creating Construction Projects
The simulations allow the creation of a coherent synthetic environment that allows the integration of simulated systems in the early analysis phase, through mixed virtual systems, with prototypic components in a virtual test environment for the final system. If managed correctly, the environment can be migrated from development and testing to training and education in later life cycle phases for systems (including the option to train and optimize a virtual twin of the real system, even under realistic constraints) before the first components are built. The use of M&S in engineering is well recognized. Simulation technology belongs to the toolkit of engineers in all application domains and has been included in the engineering management body of knowledge. M&S helps to reduce costs, increase the quality of products and systems, and enable their documentation. To ensure that simulation results are applicable in the real world, one must understand the assumptions, conceptualizations, and constraints of its implementation. In addition, the models can be updated and improved using the results of real experiments. Based on this information, the ways in which the user interface can be optimized were analyzed and simulations were carried out at a standard speed without any limitation, a FAST 3G speed, and a SLOW 3G speed. The testing of the interfaces was followed from the point of view of the resources used and the loading and response times. The simulations are presented in Figures 5-7, the waiting times being distinctly marked with the green color, the download times for downloading the content are marked with the blue color, the requests and jumps with the gray color. Perhaps one of the most important factors regarding the improvement process of loading an application made at the infrastructure level is the total size of each file in a package. When third-party modules are added to the projects, each of those dependencies in turn has other sub-dimensions that generate bottlenecks. Following the reeds, it was observed that for each entity that was operated roughly, a larger number of components were generated, which then made the listing layout more difficult. Therefore, for each entity, those components must list each item on a gradual scale, and the layout implements a new generic logic that efficiently manages each raw operation. Figure 5: Simulation without any loading—first page. Figure 6: FAST 3G limited simulation—first page load. Figure 7: Simulation with SLOW 3G limitation—loading the first page. Thus, the new layout contains n number of components, but all the entities that lead to the generation of that layout have a single purpose, that of generating a defined ideal component. Within the new layout, generic modules are created that reload whenever a new intermediate module is needed through which a dynamic dialogue is managed, facilitating the listing or processing of data from any area of the Coestim application. ### Testing and Validating the Designed Application by Overloading the Databases

In this direction, the problem of database testing was addressed, by overloading the database in relation to the estimated traffic in the conditions where the designed application will have the role of e-commerce platform, service reservation platform, and construction design generation. Under these conditions, many more categories of users are targeted than on a standard building materials platform. \"Functional database testing\" refers to the method of testing a database that aims to validate the functional requirements at the data infrastructure level from the end user's point of view. We can say that the main purpose is to test and validate the transactions or operations performed by an end user who accesses the database, the result being boolean in terms of compliance. \"Non-functional testing\" in the context of database testing can be classified into different categories depending on the application requirements.