Bottom Left Algorithm Research Articles

Research on irregular sponge layout system based on heuristic algorithms

Abstract A layout optimization method that integrates No-Fit Polygons (NFP) positioning and a genetic algorithm is proposed for the two-dimensional irregular sponge packing problem. Firstly, according to the geometric characteristics of the parts, they are classified and encoded to calculate the NFP between part classes, avoiding redundant NFP calculations. Simultaneously, heuristic rules aimed at minimizing the packing height are introduced to provide a comprehensive evaluation function for part positioning strategies, thus improving packing efficiency. Secondly, in the optimization of part sorting, a genetic algorithm is introduced to optimize the sponge packing algorithm. Finally, several standard cases provided by the European Special Interest Group on Cutting and Packing (ESICUP) are used to test the proposed packing method. The results show that compared to the traditional Bottom-Left algorithm, the computational efficiency of the proposed packing method is improved by 4.20% to 22.73%.

Research on airport apron planning strategy in emergency situations

In events of local war or highly infectious epidemics, airports face the problem of how to park numerous non-missioned aircraft on aprons. In this study, the apron planning problem in emergency situations (APPES) was considered to replan existing parking stands and taxiways, thus determining the numbers and locations of different aircraft types. A mixed-integer programming formulation for the APPES was developed to maximise the total revenue for the apron, where the aircraft was planned to be parked based on factors such as the safety distance and aircraft taxiing method. A two-stage approach based on the discrete particle swarm optimisation algorithm and bottom-left algorithm was designed to solve the APPES. Random instances of different sizes were generated, and the experimental results demonstrated the effectiveness of the proposed approach. The two-stage approach could find optimal solutions to the APPES for 19 of the 20 small instances and could well approximate optimal solutions for the medium and large instances within a reasonable timeframe. Parking priority factor and aircraft taxiing methods sensitivity analyses were also designed to develop a strategy that can adhere to the preferences of decision makers or increase the total revenue.

A Novel Automatic Green Design Based on Intelligent Algorithm

In order to make a novel green design, the modified remaining rectangle layout method based on Bottom-Left algorithm and genetic algorithm is proposed, the area of photovoltaic modules laying on the surface of the roof can be maximized automatically by computer. The best laying diagram is shown; the best inverters are chosen considering both efficiency and price; the photovoltaic modules and inverters connection scheme which meets the requirements is shown.

Two-Dimensional Irregular Packing Algorithm for Strips Cutting Technology in Sheet Steel Industry

This paper proposes a new packing algorithm for strips cutting method in steel plate cutting technology. It remarks the shapes by many horizontal lines. It firstly searches the best sequence and each shape’s angle for packing all shapes by genetic simulated annealing algorithm, and then a new heuristic algorithm which satisfies the practical need of strips cutting technology based on the bottom-left algorithm is used to complete the automatic layout of two dimensional irregular shapes. In the end, satisfactory results of optimal layout are obtained.

Layout Design of Functional Modules and Routing for Their Connection Considering the Route Divergence and Confluence. Layout Design of Modules and Routing for Automatic Teller Machines.

This paper deals with a simultaneous optimization of the layout of the functional modules and routing for their connection. To shorten the route length, a renovated routing method, the direction-oriented maze routing (DOMR), which has a function of divergence and confluence of the transportation routes is proposed. This method is applied to the design of module layout for automatic teller machines (ATM) including the layout of bill circulation routes as well. In the optimization process, the layout of module is first searched by the Bottom-Left (BL) algorithm; since the module layout depends on the order of operation in the BL algorithm, a genetic algorithm is used to determine the best order of the BL operation keeping pace with the DOMR. The obtained design solution is compared with the existing actual ATM and the effectiveness of the proposed design method is evaluated.