Indiana University-Purdue University Indianapolis (IUPUI) / The internal and external interactions between the complex structural and behavioral
characteristics of the system of interest and the surrounding environment result in unpredictable
emergent behaviors. These emergent behaviors are not well understood, especially
when modeled using the traditional top-down systems engineering approach. The intrinsic
nature of current complex systems has called for an elegant solution that provides an
integrated framework in Model-Based Systems Engineering. A considerable gap exists to
integrate system engineering activities and engineering analysis, which results in high risk
and cost. This thesis presents a framework that incorporates indefinite and definite modeling
aspects that are developed to determine the complexity that arises during the development
phases of the system. This framework provides a workflow for modeling complex systems
using Systems Modeling Language (SysML) that captures the system’s requirements, behavior,
structure, and analytical aspects at both problem definition and solution levels. This
research introduces a new level/dimension to the framework to support engineering analysis
integrated with the system architecture model using FMI standards. A workflow is provided
that provides the enabling methodological capabilities. It starts with a statement of
need and ends with system requirement verification. Detailed traceability is established that
glues system engineering and engineering analysis together. Besides, a method is proposed
for predicting the system’s complexity by calculating the complexity index that can be used
to assess the complexity of the existing system and guide the design and development of a
new system.
To test and demonstrate this framework, a case study consisting of a complex district
cooling system is implemented. The case study shows the framework’s capabilities in enabling
the successful modeling of a complex district cooling system. The system architecture
model was developed using SysML and the engineering analysis model using Modelica. The
proposed framework supports system requirements verification activity. The analysis results
show that the district chiller model developed using Modelica produces chilled water below
6.6 degrees Celsius, which satisfies the system requirement for the district chiller system
captured in the SysML tool. Similarly, many such requirement verification capabilities using dynamic simulation integration with the high-level model provides the ability to perform
continuous analysis and simulation during the system development process. The systems architecture
complexity index is measured for the district cooling case study from the black-box
and white box-perspective. The measured complexity index showed that the system architecture’s
behavioral aspect increases exponentially compared to the structural aspect. The
systems architecture’s complexity index at black-box and white-box was 4.998 and 67.3927,
respectively.
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/24784 |
| Date | 12 1900 |
| Creators | Dalvi, Akshay Satish |
| Contributors | El-Mounayri, Hazim, Razban, Ali, Anwar, Sohel |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Rights | Attribution-NoDerivatives 4.0 International, http://creativecommons.org/licenses/by-nd/4.0/ |
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