scholarly journals Quantifying Multi-Parameter Dynamic Resilience for Complex Reservoir Systems Using Failure Simulations: Case Study of the Pirot Reservoir System

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3157
Author(s):  
Lazar Ignjatović ◽  
Milan Stojković ◽  
Damjan Ivetić ◽  
Miloš Milašinović ◽  
Nikola Milivojević

The objective of this research is to introduce a novel framework to quantify the risk of the reservoir system outside the design envelope, taking into account the risks related to flood-protection and hydro-energy generation under unfavourable reservoir element conditions (system element failures) and hazardous situations within the environment (flood event). To analyze water system behavior in adverse conditions, a system analysis approach is used, which is founded upon the system dynamics model with a causal loop. The capability of the system in performing the intended functionality can be quantified using the traditional static measures like reliability, resilience and vulnerability, or dynamic resilience. In this paper, a novel method for the assessment of a multi-parameter dynamic resilience is introduced. The multi-parameter dynamic resilience envelops the hydropower and flood-protection resilience, as two opposing demands in the reservoir operation regime. A case study of a Pirot reservoir, in the Republic of Serbia, is used. To estimate the multi -parameter dynamic resilience of the Pirot reservoir system, a hydrological model, and a system dynamic simulation model with an inner control loop, is developed. The inner control loop provides the relation between the hydropower generation and flood-protection. The hydrological model is calibrated and generated climate inputs are used to simulate the long-term flow sequences. The most severe flood event period is extracted to be used as the input for the system dynamics simulations. The system performance for five different scenarios with various multi failure events (e.g., generator failure, segment gate failure on the spillway, leakage from reservoir and water supply tunnel failure due to earthquake) are presented using the novel concept of the explicit modeling of the component failures through element functionality indicators. Based on the outputs from the system dynamics model, system performance is determined and, later, hydropower and flood protection resilience. Then, multi-parameter dynamic resilience of the Pirot reservoir system is estimated and compared with the traditional static measures (reliability). Discrepancy between the drop between multi-parameter resilience (from 0.851 to 0.935) and reliability (from 0.993 to 1) shows that static measure underestimates the risk to the water system. Thus, the results from this research show that multi-parameter dynamic resilience, as an indicator, can provide additional insight compared to the traditional static measures, leading to identification of the vulnerable elements of a complex reservoir system. Additionally, it is shown that the proposed explicit modeling of system components failure can be used to reflect the drop of the overall system functionality.

2021 ◽  
Author(s):  
◽  
Jason Yves Markham

<p>Despite unresolved controversy and ongoing debate about user confidence in system dynamics models, there has been limited empirical exploration of the concept of user confidence in system dynamics models. This research elicited the concept of user confidence using a framing method (Russo & Schoemaker, 1989); analyzed the confidence criteria using constant comparative analysis (Cavana, Delahaye & Sekaran, 2001) and organized the confidence criteria into a descriptive framework. This research was conducted as an ethnographic case study of a New Zealand Army workforce planning problem. The simultaneous objectives of this research were to elicit the concept of user confidence in a system dynamics model and to assess the usefulness of the framing method for ascertaining user confidence criteria. The findings suggest that users of a system dynamics model had unique views of confidence, and while these views changed during the model-building project, they shared a common perspective of utility. Interestingly, user confidence criteria did not change significantly between the qualitative and quantitative stages of model-building. Output from the system dynamics workforce model supported the dynamic hypothesis that the use of ‘aspirational’ separation forecasts have contributed to New Zealand Army workforce shortfalls during times of high labour demand. Additionally, framing proved to be a useful methodology for eliciting and interpreting the elusive concept of user confidence in this case study. This case study concludes that although the confidence criteria of model users are diverse, extensive and difficult to elicit; framing can be employed as an interpretive filter to ascertain the elements of user confidence.</p>


2021 ◽  
Author(s):  
◽  
Jason Yves Markham

<p>Despite unresolved controversy and ongoing debate about user confidence in system dynamics models, there has been limited empirical exploration of the concept of user confidence in system dynamics models. This research elicited the concept of user confidence using a framing method (Russo & Schoemaker, 1989); analyzed the confidence criteria using constant comparative analysis (Cavana, Delahaye & Sekaran, 2001) and organized the confidence criteria into a descriptive framework. This research was conducted as an ethnographic case study of a New Zealand Army workforce planning problem. The simultaneous objectives of this research were to elicit the concept of user confidence in a system dynamics model and to assess the usefulness of the framing method for ascertaining user confidence criteria. The findings suggest that users of a system dynamics model had unique views of confidence, and while these views changed during the model-building project, they shared a common perspective of utility. Interestingly, user confidence criteria did not change significantly between the qualitative and quantitative stages of model-building. Output from the system dynamics workforce model supported the dynamic hypothesis that the use of ‘aspirational’ separation forecasts have contributed to New Zealand Army workforce shortfalls during times of high labour demand. Additionally, framing proved to be a useful methodology for eliciting and interpreting the elusive concept of user confidence in this case study. This case study concludes that although the confidence criteria of model users are diverse, extensive and difficult to elicit; framing can be employed as an interpretive filter to ascertain the elements of user confidence.</p>


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zili Tai ◽  
Ji Guo ◽  
Yeli Guan ◽  
Qingquan Shi

Since the end of 2019, the outbreak of COVID-19 has severely affected port production and operation. There is little research on the systematic impact assessment. This study took Shanghai Port as an example and evaluated the impact under different scenarios through establishing a System Dynamics model. It is found that the epidemic mainly has a greater impact on passenger transport, but less on cargo transport. The ports with the function of transportation in highway, railway, and waterway were the key nodes in the international logistics network. More attention should be paid to the impact assessment of COVID-19 on ports’ production and operation. It is necessary to strengthen the port’s collection and distribution capabilities, improve port production efficiency, and further strengthen port modernization. This research method proposed in this paper can provide a reference for the impact assessment of similar events, and the empirical results can provide a reference for handling the epidemic shock for the port and shipping departments.


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