Research On Stream Line Optimization Based On Matching Degree

There exists a typical social economic activity which includes urban and regional economic activities in macroscopic level; manufacture, trade and consumption in microcosmic level. It is called logistics. It includes the process of storage, manufacture, transportation, distribution, package, and assembling and disassembling. The claim of quantity, arriving time and cost of the goods from both the logistics organizer and the demander construct a typical logistics supply and demand network. In this thesis, this supply and demand network is called streamline network (SLN) which consists of some specific node, string and given weight.Different from traditional logistics network, SLN has a complex structure, which is nested, multilayer, multi-level, multi-dimension and multi-criteria. It not only reflects the characteristic of logistic supply and demand network in logistics service, but also describes the relationship between the supply and demand network in logistics service. The logistics supply network (of its ability and service) can be optimized according to the network characteristics of varied logistics demands. This optimization can reveal general rules and characteristics of typical logistics activities, optimize logistics organization plan, satisfy the customer’s demand, so to realize the essence of logistics service, that is to say taking right quantity of right goods to right place in right time by right route with right cost.Firstly, it analyzed the typical logistics activities existed in manufacture, trade, consumption, urban and regional economy summarizes its characteristics, general streamline form and distinguish figures of streamline, so to find out the general structure and mathematical definition of SLN. And then, it analyzed basic structure, degenerate structure, matrix description and the characteristics of statistic, attribute and composite weight.Secondly, by analyzing the time, quantity and cost of the logistics supply and demand, it can borrow the general cost function to unify time, quantity and cost, so to give a definition and mathematic description of the matching degree of supply and demand in node and arc among the streamline network. It can establish a model to show matching degree of supply and demand. Through introduced vector function to analyze the node, string and matching between supply and demand in all levels, it extended the calculation formula of supply and demand matching degree from node, arc to the whole network. It can also establish a model of streamline evaluation and selection based on the model of matching degree between supply and demand, and verified it in a case as the regional installation layout in a distribution center.Thirdly, this thesis established an optimized streamline model, with the matching degree between supply and demand as the objective function, and capacities and resource as the constraint. In the meantime, the selection and evaluation models as well as the optimized streamline model mainly guided by benefit, weak benefit and efficiency were constructed. The model was converted to a variation inequality with or without constraint by the equivalence relation between variation inequality and optimizing model. It proved that the model has a unique way of solution. According to projection algorithm, the streamline model optimization algorithm is put forward.At last, taking the spatial distribution of the logistics nodes in one city as a sample, by using the streamline optimization theory and method to explain the streamline network model of logistics nodes’spatial distribution, it established a streamline optimization model which takes the quantity matching degree as its objective function; also proved the effectiveness and feasibility of the model because found out a better distribution scheme than experience comparative method through mathematic-solving. Another sample was the organization optimization of logistic transportation in one steel factory. Based on the sample, established a streamline optimization no-linear plan model using the matching degree of supply and demand as the objective function, and then changed it into variation inequality. Then ILOG CPLEX software, fixed step iterative algorithms and variable step iterative algorithms was used to solve this model. Comparing those three methods, it can find out their advantages and disadvantages.The research shows, streamline is a complex super network. It is multi-level, multi-layer and multi-attribute. The matching degree of supply and demand in streamline network can describe the approaching degree of supply and demand in logistic service better. Streamline optimization model is a no-linear plan model which uses matching degree of supply and demand as objective function, resource and capability limitation as constraint condition. Its equivalent form of variation inequality has only one solution. Improved variable step iterative algorithm can be solved to streamline optimization model in inequality form. This sample proves that this algorithm is better than fixed-step iterative algorithm.The structure model and mathematical description of streamline network can offer a general structure and a research platform for typical logistics activities, it helps to reveal the nature and rules of logistics service. The matching degree model of supply and demand provides a mathematical analysis way to reveal the complex relationship between logistics supply and demand network, and factors influence them. The streamline optimization model and algorithm based on variation inequality provide a new optimization method in the area of logistics optimization.This research is useful for both the construction of core theoretical system in logistics and the further study of theory and method in logistics. It can also help to settle the network distributional problem in regional social economic activities, optimize the process in manufacture activities, and solve the problem concerned with complex network distribution in trade and consumption. It is significant in theoretical and practical guidance.