A new improved algorithm to optimize the parameters of a diversified supply strategy considering the transportation features for the EOQ-models is proposed. When optimizing decisions it will allow for the first time to take into account the following attributes of the simulated supply chain: 1) cargo capacity of the vehicles used; 2) a possibility of selecting their types when delivering goods; 3) the format of paying storage costs (rent or paying only for occupied places at the warehouse); 4) expediency of deliveries using several vehicles if there are discounts on the cost of such deliveries; 5) factor of time value of money taking into account the efficiency of cash flows of the supply chain itself; 6) assessment of the expected return on the working capital of the simulated supply chain; 7) specificity of such a profitability indicator taking into account the utilization of the cargo capacity of the vehicles used at the deliveries. This algorithm was developed with reference to special EOQ-models. Namely, it relates to a class of models interesting and important for business when profit can be made at each reorder interval. The models in question are those where profit during the reordering interval can be used both to cover part of the costs at that interval and to make payment of the next delivery. Therefore, the format of the algorithm will consider necessary and sufficient conditions fulfillment of which allows to ensure the possibility of these payments from the profit during the supply chain operation.
Article continues subjects of modeling of the logistical centers (LC). Definition of operational model LC is made. Typical variants of construction of operational model from simple model of rent of the warehouse areas to operational model LC of high level with participation of the 4PL-provider are considered. The algorithm of a choice of logistical operators in LC, based on a method of a rating estimation is offered. Variants of operational
model LC with participation 3PL and 4PLпровайдеров are analysed. It is considered функционал the 4PL-provider in aspects of interorganizational coordination of counterparts LC.
The success of any logistics provider under the development of a digital economy directly depends on the decision-making system, taking into account the dynamic nature of the environment and the optimal construction of the internal structure. In an effort to ensure a stable economic position in a competitive market, they pay more attention to both process monitoring, management system analysis and forecasting tasks. At the same time, classic models based on imitating modelling of processes and systems are proposed; for the study of control models, it is necessary to supplement the analysis based on structural diagrams and dynamic links. The use of dynamic links significantly expands the functionality of modelling methods and allows not only to investigate the stock turn, but also to simulate the control actions on the system to achieve the specified parameters. Modelling processes based on dynamic links allows us to investigate the stability of logistics systems, to assess the impact of disturbances on the system and elements. The proposed management model for the logistics system is implemented according to the feedback control principle, which additionally contributes to the formation of a more accurate decision-making system. The developed model has the ability to scale for different levels of planning and takes into account the dynamic nature of the processes in the logistics system, taking into account the influence of the environment. The article additionally outlines the limits of application of simulation modelling in the AnyLogic environment for the study of control systems, which substantiates the practical importance of using structural diagrams and dynamic links for logistic systems.
The problem of development of the modern theory of inventory management is relevant and one of the priority directions of development of economic science to reduce logistics costs in the supply chain and to improve their efficiency.
The article deals with the model of economic order quantity (EOQ) and its place in the inventory management theory; the base and corrected version of the model which allows differing the accounting of costs related to the current stock storage have been analyzed; the approach for the assessment of the stability of EOQ model, reflecting the deviation of total logistics costs of their optimal value depending on changes in the value of the order quantity have been proposed.
The accuracy of calculating of economic order quantity depends on many factors: how many components of the costs are taken into account and their relationship, what version of the model is selected, but primarily on the accuracy of the parameters included in it; to evaluate the accuracy of calculating the economic order quantity and, consequently, the total costs derived formulas to determine the mean values and standard deviations of these values based on the linearization of distribution functions of random arguments; for approval of the proposed dependencies the examples of calculations have been done; the possible directions of EOQ model further research have been generalized. In particular, there is need for a reasonable complexity of the model, its differentiation, without which it is impossible to bring the analytical dependences for practical applications
The concept of cross-functional coordination defines the interaction of business units, which gives the overall optimal results of the company. Difficulties associated with interaction of the various units are typical for enterprises of different sectors of economy. One of the most important issues in trade enterprises is the problem of interaction of departments of marketing and logistics in determining the optimum level of customer service. The problem is in searching a balance between the level of logistic service provided to consumers, and the level of total logistic costs associated with maintaining a defined level of service. The purpose of this study is to develop a mathematical optimization model of logistic service of trade enterprises. It is assumed that logistic service of the enterprise has a number of components (indicators) of service, each of which has different variants (possible values). Implementation of the service component in a particular variant, affect the values of revenue and total costs of the enterprise. It is necessary to find such a combination of variants of service components, which will provide the maximum profit for trade enterprise. To achieve this goal the analysis of the external environment of trade enterprise is carried out; conceptual and structural optimization models are developed. On their basis the mathematical model of linear programming (LP) is developed. The LP model is tested on a numerical example, so a tabular model is also created. For the stage-by-stage solution of the optimization problem, the LP model is transformed to model of dynamic programming. The limits of applicability of the models are defined. The study developed a mathematical model of linear programming with Boolean variables, which provides finding optimal variants of logistic service components and complies with the restrictions. As an alternative, a dynamic programming model is developed. An important advantage of this model is the possibility, during the phased decision-making, to implement a satisfactory solution, from the point of view of decision-maker, and not mathematically optimal solution. The progress and results of the study shows that total logistic costs, which are the main component of models, require detailing, and the process of their formation - definition of mathematical ratios, with the aim of developing integrated model for determining the optimal level of service and costs of subsystems of the logistics system of trade enterprise.
The article presents a special modification of the EOQ-formula for a diversified EOQ-model of inventory management with account to specifics of lot deliveries. It will allow managers to determine the optimal parameters of the inventory management strategy if it is required to take into account the following features: 1) the possibility of order payment deferral; 2) time value of money at cashflow modelling 3) incomes specifics, when the proceeds come with a delay 4) specificity of storage costs payment (in form of rent or by the occupied storage space). In addition, the article specifies some options related to the possibility of using such a formula if it is necessary to additionally take into account: a) the restriction on the allowable length of the delay in payment of goods, so that the point of receipt of the proceeds did not exceed the corresponding reorder interval duration (on average); b) the vehicle capacity. The presented research materials on optimization of supplies will allow managers to estimate the effect of permissible delays in order payments, delays in receipt of proceeds, and the factor of vehicle capacity on the parameters of the optimal strategy of inventory management. The procedures of EOQ formula modification for inventory management systems are performed in relation to interesting and business-relevant models of this type that correspond to efficient deliveries, where these delays allow to make order payments from revenue at reordering intervals.