China
Africa
Explore chapters and articles related to this topic
Materials Selection Process
Published in Mahmoud M. Farag, Materials and Process Selection for Engineering Design, 2020
Answering these questions makes it necessary to specify the performance requirements of the component and to broadly outline the main material characteristics and processing requirements. On this basis, certain classes of materials and manufacturing processes may be eliminated and others chosen as likely candidates for making the component. The relevant material properties are then identified and ranked in the order of importance. Candidate materials that possess these properties are then graded according to their expected performance and cost. Processing details are also examined at this stage. Optimization techniques may then be used to select the optimum material and processing route. This may result in design modifications to achieve production economy or to suit the available production facilities and equipment. Even in the stage of product manufacture, some changes in materials may be necessary. Processing problems may arise causing the replacement of an otherwise satisfactory material. For example, heat treating, joining, or finishing difficulties may require materials substitution that, in turn, may result in different service performance characteristics requiring some redesign.
Flight Planning
Published in Yasmina Bestaoui Sebbane, Multi-UAV Planning and Task Allocation, 2020
An approach is described in this section for dynamic route optimization for an autonomous aircraft [370]. A multi-resolution representation scheme is presented that uses B-spline basis functions of different support and at different locations along the trajectory, parametrized by a dimensionless parameter. A multi-rate receding horizon problem is formulated as an example of online multi-resolution optimization under feedback. The underlying optimization problem is solved with an anytime evolutionary computing algorithm. By selecting particular basis function coefficient as the optimization variables, computing resources can flexibly be devoted to those regions of the trajectory requiring most attention. Representations that can allow a UAV to dynamically re-optimize its route while in-flight is of interest. A popular technique for route optimization is dynamic programming, often in combination with other methods. Way-points generated by dynamic programming serve as input to either an optimal control or a virtual potential fields approach. The potential field method models the route with point masses connected by springs and dampers. Threats and targets are modeled by virtual force fields of repelling and attracting forces. The optimized route then corresponds to the lowest energy state of this mechanical equivalent.
Energy-Efficient Optimized Routing Techniques in an IoT-Enabled Intelligent Traffic Management System
Published in Deepti Agarwal, Kimmi Verma, Shabana Urooj, Energy Harvesting, 2023
Piyush Agarwal, Sachin Sharma, Priya Matta
Better Customer Experience: The goal of logistics and cab service-like business is to make the customer experience better. In the logistics business, for positive customer feedback, on-time delivery is necessary. Many factors affect the delivery time. One of the main factors that affect the delivery is traffic congestion and the route that is followed by the delivery person to deliver the product. Route optimization techniques not only suggest the route but can also suggest the mode of transportation at different stages of the delivery, keeping to the deadline of the delivery, cost, and many other factors.
An infeasible start heuristic for the transit route network design problem
Published in Transportmetrica A: Transport Science, 2020
The approaches to route generation are heuristic, typically based on shortest path algorithms (Kepaptsoglou and Karlaftis 2009). Different methods are used to find the shortest path between selected O-D pairs (Baaj and Mahmassani 1991; Pattnaik, Mohan, and Tom 1998; Fan and Machemehl 2006; Cipriani, Gori, and Petrelli 2012; Nayeem, Rahman, and Sohel Rahman 2014). As travel time estimation is the widely accepted criterion for paths evaluation, the shortest path is the one with the minimal travel time. Bagloee and Ceder (2011) modified links’ travel time according to their closeness to transit centers. Their approach finds paths with longer travel time but considers transit centers along it.
How big data enriches maritime research – a critical review of Automatic Identification System (AIS) data applications
Published in Transport Reviews, 2019
Dong Yang, Lingxiao Wu, Shuaian Wang, Haiying Jia, Kevin X. Li
In navigation, route planning aims to help ship navigators identify a route with a low collision risk and detour cost. Route planning is built upon the results of ship domain construction and collision risk assessment. The most commonly used methods in route planning are heuristic algorithms (e.g. evolutionary algorithms and ant colony optimisation). Such studies include those of Tsou and Hsueh (2010), and Kim, Hirayama, and Okimoto (2017).
Wind-assisted, electric, and pure wind propulsion – the path towards zero-emission RoRo ships
Published in Ships and Offshore Structures, 2023
Fabian Thies, Jonas W. Ringsberg
In recent years, weather routing and speed optimisation have become an industry standard in marine transport. Route optimisation can be used to both, reduce fuel consumption and structural loads and fatigue (Wang 2020). Using ShipCLEAN as a performance prediction model, Li et al. (2020) developed a dynamic voyage prediction tool to include variable predictions, observations, and ice navigation in the routing.