Design and application of digital management system for the sinter raw material plant
To solve the problems existed in iron and steel enterprise material plant, such as complex sources resulting in variety of materials, inaccurate inventory statistics leading to high cost, unpredictable external factors affecting material plant, etc., a digital management system is introduced in this paper. Firstly, the practical requirements and the process of material plant are analyzed. Based on the analysis, the new grid management and material balance methods are developed. Applying these methods, a new management system for material plant is designed, whose system configuration, hardware architecture, data flow, and functions of modules are introduced in details. Such system has been implemented in a large-scale iron and steel corporation sinter raw material plant. The operation results show that, this system has excellent capabilities and a promising application future in industries.
Modeling, simulation and optimization of people traffic in elevators
This paper proposal is to investigate and understand the performance of the elevator systemr systems to optimize people traffic. Discrete event systems methodology is used in conjunction with heuristic optimization algorithm aiming to find the best scenario/symetric that reduces waiting time in elevators queues. The system modeling considers passive elements (queues) and active (processors/servers). The results show that changes in elevator scenario can shorten queuing time by up to 12.82% and with the optimization scenario 31,83%.
Lagrangian heuristics for the two-echelon, single-source, capacitated facility location problem
Facility location problems form an important class of integer programming problems, with application in the distribution and transportation industries. In this paper we are concerned with a particular type of facility location problem in which there exist two echelons of facilities. Each facility in the second echelon has limited capacity and can be supplied by only one facility (or depot) in the first echelon. Each customer is serviced by only one facility in the second echelon. The number and location of facilities in both echelons together with the allocation of customers to the second-echelon facilities are to be determined simultaneously. We propose a mathematical model for this problem and consider six heuristics based on Lagrangian relaxation for its solution. To solve the dual problem we make use of a subgradient optimization procedure. We present numerical results for a large suite of test problems. These indicate that the lower-bounds obtained from some relaxations have a duality gap which frequently is one third of the one obtained from traditional linear programming relaxation. Furthermore, the overall solution time for the heuristics are less than the time to solve the LP relaxation.