## 3 Research Design
### Conceptual Model for Project Resilience Assessment
#### 3.1.3 Project Resilience Curves  
In order to establish a conceptual model for resilience assessment, the following analyses the project's response process to disruption and the changes in its performance level and specifies the characteristics of the associated resilience capabilities. In particular, the performance level of the system can be assessed from different perspectives and using different indicators, and different performance metrics correspond to different dimensions of the project's resilience. Different performance indicators can be selected to characterize the different performance levels of the project, such as the progress level of the project, which can be selected as an SPI. Recording the performance level of the project at time t as PI(t), as shown in Figure 2, the performance level of the project changes after the disturbance in four stages as shown below:  
Figure 2: Resilience curve schematic diagram.  
Initial stage (t < t1): the normal operation phase of the project before it encounters a sudden event. In this phase, the project's performance level P(t) remains at the initial level PIO.  
Disruption stage (t1 \(\leq\) t \(\leq\) t2): In the event of a disruption occurring at the beginning of t1, it can be assumed that the project will be damaged and destroyed solely at that moment. Concurrently, as the project is a temporary organization, the consequences of the catastrophic event will gradually spread throughout the project to the entire organization, ultimately resulting in certain consequences of the disaster. This can be exemplified by the performance level of the network at moment t1, P(t), which declines from PIO to a certain value. The decline curve of the project performance level in this phase portrays the project's ability to resist and recover from the disruption. If the project has not initiated the restoration process by the end of the decline in P(t) at t2, the project will reach the minimum performance level PID1 at time t2.  
Recovery stage (t2 < t \(\leq\) t3): During this phase, the project initiates a process of gradual recovery, with the objective of restoring the project performance level P(t) to its original state. This may entail a number of adjustments, including resource reallocation, process optimization, or the activation of contingency plans. In order to accelerate the recovery process, the project may increase its resources, which can be divided into two categories: expendable resources (e.g., money, replacement facilities, and equipment, etc.) and non-expendable resources (e.g., tools, personnel, etc.). The evolution curve of the project's performance level during the phase is determined by the recovery resources owned by the project and the proposed recovery strategy or plan, in conjunction with the aforementioned resources. The investment of these resources facilitates the prompt resolution of legacy issues and the enhancement of operational efficiency. Following a period of adaptation and adjustment, the performance level of the project gradually stabilizes at t3.  
Stable stage (t > t3): After going through the disaster recovery phase, the project will be in a new stable operation phase. In this phase, the level of project performance recovery depends on its own recovery capability as well as its recovery strategy and can exhibit three different types of recovery:  
Situation 1: The system recovers to the original performance level PIO;  
Situation 2: The system recovers to a higher level of performance PIR1;  
and Situation 3: The system produces a partial loss of performance up to PIR2.