Path Planning of AS/RS Based on Cost Matrix and Improved Greedy Algorithm

Logistics plays an important role in the field of global economy, and the storage and retrieval of tasks in a warehouse which has symmetry is the most important part of logistics. Generally, the shelves of a warehouse have a certain degree of symmetry and similarity in their structure. The storage and retrieval efficiency directly affects the efficiency of logistics. The efficiency of the traditional storage and retrieval mode has become increasingly inconsistent with the needs of the industry. In order to solve this problem, this paper proposes a greedy algorithm based on cost matrix to solve the path planning problem of the automatic storage and retrieval system (AS/RS). Firstly, aiming at the path planning mathematical model of AS/RS, this paper proposes the concept of cost matrix, which transforms the traditional storage and retrieval problem into the element combination problem of cost matrix. Then, a more efficient backtracking algorithm is proposed based on the exhaustive method. After analyzing the performance of the backtracking algorithm, combined with some rules, a greedy algorithm which can further improve efficiency is proposed; the convergence of the improved greedy algorithm is also proven. Finally, through simulation, the time consumption of the greedy algorithm is only 0.59% of the exhaustive method, and compared with the traditional genetic algorithm, the time consumption of the greedy algorithm is about 50% of the genetic algorithm, and it can still maintain its advantage in time consumption, which proves that the greedy algorithm based on cost matrix has a certain feasibility and practicability in solving the path planning of the automatic storage and retrieval system.

Introduction: A Thousand Platoons – The Enduring Importance of Esprit de Corps

The French use of ‘esprit de corps’ is often political and suggests a form of cognitive uniform generated by a more or less conscious adherence to a collective body. However, the phrase is more used today in English than in French because it has gained in the former language a general and often uncritical meaning (signifying more or less team spirit). This chapter gives contemporary examples that demonstrate the ubiquity of ‘esprit de corps’ in today’s global discourses, for example political (Brexit, Trump) or managerial (team spirit). It briefly analyses the rare literature on the matter, explains the systematic and exhaustive method followed in this book (‘histosophy’), and explains why a longue-durée genealogical and transnational approach was chosen and how this was possible thanks to digital archives and primary sources.

The Single-Vendor Multibuyer Integrated Production-Delivery Model with Production Capacity under Stochastic Lead Time Demand

In this paper, we consider an integrated production-delivery model in which a vendor supplies the same product to multiple buyers. Unlike existing study, in this proposed model, we assume that the sum of all buyers’ demand rates is larger than the vendor’s production rate under normal work, but less than that under overtime. All buyers are independent of each other. For each buyer, the lead time demand is stochastic and the shortage during lead time is permitted. The main objective of this model is to determine the optimal production and delivery policies and the optimal overtime strategy, which minimize the joint expected annual cost of the system. Based on the genetic algorithm, we develop a solution procedure to find the optimal production, delivery, and overtime decision of this model. Computational experiments show the error rate between the objective values obtained by the proposed solution procedure and the solutions solved by the exhaustive method. The results indicate that the proposed mixed genetic algorithm is more effective and adoptable in comparison with the exhaustive method as it can be able to calculate the optimal solutions for at least 96% for the instances. Ultimately, an adequate numerical example is given to show the detailed process of the solution procedure, and sensitivity analysis of main parameters with managerial implication is discussed.

Exploring Practicability for Solving a Task Based on the Generalized Cellular Automata via SAT Solvers

The paper deals with exploring practicability to solve a task of the recovery key of generalized cellular automata via SAT solvers.The problem, which we call a task of the key recovery of generalized cellular automata, is under consideration. This task is formulated as follows. The generalized cellular automata, the positive integer s, the initial values of some cells, and the values of some cells after the s steps of the automata are given. It is required to find the initial values of the remaining cells (their number will be called the key length).To solve the task, were tested Picosat, MiniSat, Glucose, Lingeling, and CryptoMiniSat SAT solvers. In further computational experiments, was used the MiniSat, which was the best.The key recovery task was solved for the generalized cellular automata of a small size via the MiniSat SAT solver. Pizer's graphs were used as graphs of the automata. The key length was approximately half the number of the cells in the automata. As a result of the study, it turned out that operation time of a SAT solver quite significantly (several orders of magnitude) exceeds the estimated time of solution using the FPGA exhaustive method, and the empirical dependencies of the SAT-solver operation time on the key length are exponential.The obtained results confirm that SAT solvers disable effective solving a task under consideration. This allows giving the better reasons for the cryptographic security of the crypto-algorithms based on the generalized cellular automata with regard to the cryptanalysis methods using SAT solvers.