Lead time control in multi-server multi-stage assembly system

2011 ◽  
Vol 61 (1-4) ◽  
pp. 351-368 ◽  
Author(s):  
Saeed Yaghoubi ◽  
Siamak Noori ◽  
Fatemeh Pourdadashi-Komachali
2013 ◽  
Vol 66 (4) ◽  
pp. 808-817 ◽  
Author(s):  
Saeed Yaghoubi ◽  
Siamak Noori ◽  
Amir Azaron

2007 ◽  
Vol 180 (1) ◽  
pp. 292-308 ◽  
Author(s):  
Cahit Perkgoz ◽  
Amir Azaron ◽  
Hideki Katagiri ◽  
Kosuke Kato ◽  
Masatoshi Sakawa

2021 ◽  
Vol 11 (23) ◽  
pp. 11127
Author(s):  
Qiang Wang ◽  
Jigang Chen ◽  
Haili Zhou ◽  
Xiaokang Wang ◽  
Zhanqi Hu

The staking quality of Self-lubricating Spherical Plain Bearings (SSPBs) directly affects the safety of aircraft and the service life of bearings. Reliable loading process control methods and precise process parameter indexes will come into the creation of efficacious staking quality. Therefore, this paper aims to analyze the mechanical state of the roller staking process and give a load control method and corresponding parameter indexes for the high-quality roller staking process. First, based on the analysis of quality inspection requirements, five states of the deformation degree of the flanging lip of the V groove during the roller staking process were proposed, and their relationship with the requirements was studied. Then, the mechanical states corresponding to the five deformation states of the flanging lip deformation were obtained by numerical simulation, and the feeding displacement was determined. Meanwhile, a Multi-Stage Composite Loading (MSCL) process control method was first proposed to control the material damage of the flanging lip, i.e., the rotate speed of the roller tool was constant during the roller staking process, and the displacement–time control was adopted first; when the staking load reaches a staking value, the force–time control was used to make the staking quality meet the requirements. Finally, the staking quality of the MSCL method was verified though the test. The research shows that the feeding displacement needs to be added to the requirements, and the recommended value is 0.5–0.6 times of the V groove depth. A good surface quality and non-material-damage of the flanging lip is more likely to be obtained by the MSCL process control method. The research reveals the formation mechanism of process deformation, and gives more precise process control indexes. At the same time, it provides a theoretical reference for more reliable technical standards.


2006 ◽  
Vol 174 (1) ◽  
pp. 150-168 ◽  
Author(s):  
Amir Azaron ◽  
Hideki Katagiri ◽  
Kosuke Kato ◽  
Masatoshi Sakawa

2020 ◽  
Author(s):  
Gokcen Uysal ◽  
Rodolfo-Alvarado Montero ◽  
Dirk Schwanenberg ◽  
Aynur Sensoy

<p>Streamflow forecasts include uncertainties related with initial conditions, model forcings, hydrological model structure and parameters. Ensemble streamflow forecasts can capture forecast uncertainties by having spread forecast members. Integration of these forecast members into real-time operational decision models which deals with different objectives such as flood control, water supply or energy production are still rare. This study aims to use ensemble streamflows as input of the recurrent reservoir operation problem which can incorporate (i) forecast uncertainty, (ii) forecasts with a higher lead-time and (iii) a higher stability. A related technique for decision making is multi-stage stochastic optimization using scenario trees, referred to as Tree-based Model Predictive Control (TB-MPC). This approach reduces the number of ensemble members by its tree generation algorithms using all trajectories and then proper problem formulation is set by Multi-Stage Stochastic Programming. The method is relatively new in reservoir operation, especially closed-loop hindcasting experiments and its assessment is quite rare in the literature. The aim of this study is to set a TB-MPC based real-time reservoir operation with hindcasting experiments. To that end, first hourly deterministic streamflows having one single member are produced using an observed flood hydrograph. Deterministic forecasts are tested with conventional deterministic optimization setup. Secondly, hourly ensemble streamflow forecasts having a lead-time up to 48 hours are produced by a novel approach which explicitly presents dynamic uncertainty evolution. Produced ensemble members are directly provided to input to related technique. Uncertainty becomes much larger when managing small basins and small rivers. Thus, the methodology is applied to the Yuvacik dam reservoir, fed by a catchment area of 258 km<sup>2</sup> and located in Turkey, owing to its challenging flood control and water supply operation due to downstream flow constraints. According to the results, stochastic optimization outperforms conventional counterpart by considering uncertainty in terms of flood metrics without discarding water supply purposes. The closed-loop hindcasting experiment scenarios demonstrate the robustness of the system developed against biased information. In conclusion, ensemble streamflows produced from single member can be employed to TB-MPC for better real-time management of a reservoir control system.</p>


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