Research and Forecasting Conduct logistics systems in practice carried out by means of economic-mathematical modeling, ie describing logistic processes in- as models.
Under the model in this case refers to a map of logistics system (abstract or material), which can be used instead to study its properties and possible behaviors.
In constructing such models should observe the following requirements:
• behavior structure and functions of the model should be adequate to the simulated logistic system;
• deviation of the model parameters during its operation from the corresponding parameters of the simulated logistic system should not go beyond acceptable simulation accuracy;
• results of the study model and its behaviors should reveal new properties of the simulated logistic system are not reflected in the original material used to produce this model;
• The model should be more convenient than its real counterpart - the logistics system.
Compliance with these requirements allows for qualitatively new modeling capabilities, namely:
• conduct research at the design stage logistics system to determine whether its creation and application;
• conduct research without interference with the functioning of the logistics system;
• determination of maximum permissible values \u200b\u200bof the volumes of material flow and other parameters of the logistic system without risking the destruction of the simulated system.
All models are logistic systems are divided into two classes: isomorphic and homomorphic.
Isomorphic models are the full equivalent of all the morphological and behavioral characteristics of the simulated system and can completely replace it. However, to construct and explore the isomorphic model is practically impossible due to incomplete and imperfect knowledge of the real system and the lack of adequate methods and means of such simulations.
Therefore, almost all models used in logistics, are homomorphic, which represent a model similar to the imaged object only in relationships, distinctive and important for the modeling process. Other aspects of the structure and functioning at a homomorphic simulation are ignored.
Homomorphic model are divided into material and abstract concept.
material models are in logistics management of limited use because of the difficulty and high cost play on this kind of basic geometric models, physical and functional characteristics of the original and extremely limited opportunities variation in their process of working with the model.
Therefore, logistics is mainly used by the abstract conceptual models, which are divided into Symbolic and mathematical.
Character models are built based on different, organized in certain way of signs, symbols, codes, words, or arrays of numbers representing the original study. To construct such models are used such symbols or codes that are uniquely, not allowing to varying interpretations, represent the simulated structures and processes. For example, for language description of the models used by special properly constructed vocabularies (thesauri), which, unlike conventional dictionaries, each word has only one definite value.
Information obtained through the use of character models, it is inconvenient to handle (although this is possible) for further use in the logistic management. Therefore, the most widely used in the creation and operation of logistics management Mathematical models. Mathematical Simulation is an analytical and simulation.
feature of analytic models is that the patterns of structure and behavior of an object modeling are described in an acceptable form exact analytical relations. These relations can be obtained, both theoretically and experimentally. The theoretical approach is applicable only for simple components and systems that allow a strong simplification and a high degree of abstraction. In addition, difficult check the adequacy of the resulting analytical description, since the behavior of the object is not defined in advance, and just and should be clarified as a result of the simulation. To determine this behavior, and shall be given an analytical description. Analytical description can be defined and by conducting experiments on the test object. More versatile approach has the simulation.
Simulation Model - A computer playing the deployment of the operating hours of the simulated system, ie, the reproduction of its transition from one state in another, carried out in accordance with clearly defined operating rules.
computer simulated within a controlled process, followed by analysis of simulation results to choose the final decision.
Simulation models belong to the class of descriptive models. In this machine imitation is not limited to developing only one version of the model and one-time operating it on a computer. Typically, the model is modified and adjusted: vary the original data, analyzes the various rules of objects. Tests of the model implemented in a manner to test and compare between a variety of structural variants of logistic systems. Imitation completes verification of the results and giving recommendations for practical implementation.
Simulation models are widely used to predict the behavior of logistic systems for the design and deployment of enterprise for teaching and training staff, etc.
description in the form of mathematical models of economics (logistics) process produces Economics and Mathematics methods. Algorithmic methods allow you to implement the model, which establish relationships between input and output parameters of the described component their rate of change and rates of change in these rates (ie, acceleration).
These methods are divided into economic and statistical and economic metric.
first used the description of characteristic elements, based on the mathematical and economic statistics. The second is based on a mathematical description ongoing economic processes. For example, the total wage bill clearly mathematically related to the number of employees and their distribution in discharges.
Heuristic methods are no rules for converting some of the original provision and the set of model solutions that provide though not optimal, but quite workable procedure to obtain descriptions, suitable for further modeling.
Heuristic methods divided into methods of operations research and methods of economic cybernetics. The latter, in turn, are divided on the methods of the theory of economic systems and models, methods of economic information and methods of the theory of control systems.
Economic-mathematical model - a mathematical model of the Economic Object (system process), ie, mathematically formalized study of economic an object (system process), reflecting nature, some essential properties of real economic object and processes it.
major to study mathematical economics model is its objective function. Extreme value of this function for a particular model corresponds to the best management solution for the simulated object. Descriptions of such models are also constrain the values \u200b\u200bof its parameters, which are defined as a system of equalities and inequalities. In this way, formalized these or other properties of the simulated component.
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