Research on operation cost of helicopter components based on flight condition

2009 ◽  
Author(s):  
Zhonghu Jia ◽  
Wenlin Liu ◽  
Zhiqiang Hou ◽  
Weimin Lv
Keyword(s):  
Flight Condition ◽  
Operation Cost

scholarly journals Day-Ahead and Intra-Day Optimal Scheduling of Integrated Energy System Considering Uncertainty of Source & Load Power Forecasting

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2539
Author(s):  
Zhengjie Li ◽  
Zhisheng Zhang
Keyword(s):  
Wind Power ◽  
Demand Response ◽  
Solar Power ◽  
Load Forecasting ◽  
Energy System ◽  
Optimal Scheduling ◽  
Scheduling Scheme ◽  
Load Power ◽  
Integrated Energy System ◽  
Operation Cost

At present, due to the errors of wind power, solar power and various types of load forecasting, the optimal scheduling results of the integrated energy system (IES) will be inaccurate, which will affect the economic and reliable operation of the integrated energy system. In order to solve this problem, a day-ahead and intra-day optimal scheduling model of integrated energy system considering forecasting uncertainty is proposed in this paper, which takes the minimum operation cost of the system as the target, and different processing strategies are adopted for the model. In the day-ahead time scale, according to day-ahead load forecasting, an integrated demand response (IDR) strategy is formulated to adjust the load curve, and an optimal scheduling scheme is obtained. In the intra-day time scale, the predicted value of wind power, solar power and load power are represented by fuzzy parameters to participate in the optimal scheduling of the system, and the output of units is adjusted based on the day-ahead scheduling scheme according to the day-ahead forecasting results. The simulation of specific examples shows that the integrated demand response can effectively adjust the load demand and improve the economy and reliability of the system operation. At the same time, the operation cost of the system is related to the reliability of the accurate prediction of wind power, solar power and load power. Through this model, the optimal scheduling scheme can be determined under an acceptable prediction accuracy and confidence level.

scholarly journals Percutaneous vertebroplasty versus kyphoplasty for the treatment of neurologically intact osteoporotic Kümmell’s disease

BMC Surgery ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shou-qian Dai ◽  
Rong-qing Qin ◽  
Xiu Shi ◽  
Hui-lin Yang
Keyword(s):  
Blood Loss ◽  
Bone Cement ◽  
Percutaneous Vertebroplasty ◽  
Cement Leakage ◽  
Intraoperative Blood Loss ◽  
Surgical Time ◽  
Significant Difference ◽  
Neurologically Intact ◽  
Operation Cost

Abstract Background Percutaneous vertebroplasty (PVP) and kyphoplasty (PKP) have been widely used to treat neurologically intact osteoporotic Kümmell’s disease (KD), but it is still unclear which treatment is more advantageous. Our study aimed to compare and investigate the safety and clinical efficacy of PVP and PKP in the treatment of KD. Methods The relevant data that 64 patients of neurologically intact osteoporotic KD receiving PVP (30 patients) or PKP (34 patients) were analyzed. Surgical time, operation costs, intraoperative blood loss, volume of bone cement injection, and fluoroscopy times were compared. Occurrence of cement leakage, transient fever and re-fracture were recorded. Universal indicators of visual analogue scale (VAS) and Oswestry disability index (ODI) were evaluated separately before surgery and at 1 day, 6 months, 1 year, 2 years and the final follow-up after operation. The height of anterior edge of the affected vertebra and the Cobb’s angle were assessed by imaging. Results All patients were followed up for at least 24 months. The volume of bone cement injection, intraoperative blood loss, occurrence of bone cement leakage, transient fever and re-fracture between two groups showed no significant difference. The surgical time, the operation cost and fluoroscopy times of the PKP group was significantly higher than that of the PVP group. The post-operative VAS, ODI scores, the height of the anterior edge of the injured vertebrae and kyphosis deformity were significantly improved in both groups compared with the pre-operation. The improvement of vertebral height and kyphosis deformity in PKP group was significantly better than that in the PVP group at every same time point during the follow-up periods, but the VAS and ODI scores between the two groups showed no significant difference. Conclusion PVP and PKP can both significantly alleviate the pain of patients with KD and obtain good clinical efficacy and safety. By contrast, PKP can achieve better imaging height and kyphosis correction, while PVP has the advantages of shorter operation time, less radiation volume and operation cost.

scholarly journals Estimation of Operation Cost of Residential Multiple Energy System Considering Uncertainty of Loads and Renewable Energies

IEEE Access ◽  
2020 ◽  
pp. 1-1
Author(s):  
Meihui Jiang ◽  
Tianhao Liu ◽  
Hui Hwang Goh ◽  
Dongdong Zhang ◽  
Wei Dai ◽  
...  
Keyword(s):  
Energy System ◽  
Renewable Energies ◽  
Operation Cost

scholarly journals Sensitivity Analysis of Fuzzy Activity-Based Life Cycle Costing

2018 ◽  
Vol 225 ◽  
pp. 05002
Author(s):  
Freselam Mulubrhan ◽  
Ainul Akmar Mokhtar ◽  
Masdi Muhammad
Keyword(s):  
Sensitivity Analysis ◽  
Life Cycle ◽  
Interest Rate ◽  
Life Cycle Costing ◽  
High Impact ◽  
Final Output ◽  
Left And Right ◽  
The Interest Rate ◽  
Operation Cost

A sensitivity analysis is typically conducted to identify how sensitive the output is to changes in the input. In this paper, the use of sensitivity analysis in the fuzzy activity based life cycle costing (LCC) is shown. LCC is the most frequently used economic model for decision making that considers all costs in the life of a system or equipment. The sensitivity analysis is done by varying the interest rate and time 15% and 45%, respectively, to the left and right, and varying 25% of the maintenance and operation cost. It is found that the operation cost and the interest rate give a high impact on the final output of the LCC. A case study of pumps is used in this study.

A Least Cost Transmission Planning Model Considering Operation Cost

2014 ◽  
Vol 15 (2) ◽  
pp. 121-128
Author(s):  
Jorge Hans Alayo
Keyword(s):  
Test System ◽  
Mixed Integer ◽  
Transmission Planning ◽  
Integer Linear Programming Problem ◽  
Transmission Expansion ◽  
Planning Models ◽  
Proposed Model ◽  
Expansion Model ◽  
Operation Cost ◽  
Linearization Techniques

Abstract Existing transmission planning models consider basic aspects of the problem. In practice, a transmission utility needs to model other important details such as operation cost of the power system. In this article, a least cost transmission expansion model is proposed considering the operation cost in order to model the trade-off between building new transmission capacity and increasing the power system’s operation cost. The proposed model is transformed into a mixed integer linear programming problem using linearization techniques and solved with CPLEX. Finally, results of the model for the Garver test system and IEEE 24-bus test system are shown.

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