JP2012194832A - Inventory management method, inventory management program and inventory management device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate a proper value of stock quantity to be held, of general purpose intermediate products each having a hierarchical structure and available for multiple final products, and of the final products.SOLUTION: In a computer, link information in a manufacturing process of final products and intermediate products, stochastic distribution of demand quantity expected for each final product, and excess probability of each final product and intermediate product are read, and stochastic distribution of required quantity of each intermediate product is calculated (S1, 2). Then, based on cumulative probability calculated based on the stochastic distribution of the demand quantity of each final product and the stochastic distribution of the required quantity of each intermediate product, basic quantity to be held of each final product and each intermediate product is calculated from the excess probability, and in addition, for the intermediate product, the basic quantity to be held is corrected by subtracting the basic quantity to be held of final products or intermediate products being linked and in lower levels, and the basic quantity to be held of each final product and each intermediate product is outputted as stock quantity to be held (S3-5).

Description

  The present invention relates to an inventory management method and an inventory management program for determining an inventory quantity of an intermediate product and an inventory quantity of a final product to be held during the production process in a production line in which various final products are produced through a plurality of production processes. And an inventory management apparatus.

  Traditionally, a general method for managing the inventory of intermediate products is to calculate fluctuations in the number of intermediate products in accordance with the order allocation status, and to plan production of upstream processes for intermediate products based on the results. A method of adjustment has been proposed. For example, according to the method of Patent Document 1, since the number of stocks of intermediate products is maintained at a predesignated level, orders can be reliably assigned to intermediate products, and even for products with long production lead times, from orders to shipments. The lead time can be shortened.

JP 2004-54678 A

  However, although the intermediate product inventory management method described in Patent Document 1 preliminarily gives a reference of the intermediate product inventory number (appropriate inventory number), the calculation method is not shown. In addition, in a process that achieves different characteristics of the same alloy, such as rolled products of aluminum and copper, with different stepwise processing methods, the intermediate product itself has a hierarchical structure, and the appropriate inventory quantity for each intermediate product ( It is very difficult to calculate (quantity).

  Therefore, the problem to be solved by the present invention is a general-purpose intermediate product that can be used for a plurality of final products and an inventory that can calculate an appropriate value of the inventory quantity that the final product should have. A management method, an inventory management program, and an inventory management apparatus are provided.

  The inventory management method according to the present invention is an inventory for determining an inventory quantity of an intermediate product and an inventory quantity of a final product to be held during the production process in a production line in which various final products are produced through a plurality of production processes. In the management method, the process executed by the computing unit of the computer is a product link information registration step for registering the upper and lower relationships in the manufacturing process as product link information for the final product and the intermediate product, Demand distribution distribution by final product for registering a stochastic distribution of expected demand for each final product as demand distribution by final product, and inventory is allocated to demand for each of the final product and the intermediate product. Based on the product-specific surplus probability registration step of registering the probability of remaining as a product-specific surplus probability, the final product-specific demand amount distribution, and the product link information, A required quantity distribution calculation step for each intermediate product that calculates a stochastic distribution of the required quantity for each intermediate product determined depending on the stochastic distribution of the demand quantity for each final product as an intermediate product required quantity distribution; Based on the demand distribution by end product and the requirement distribution by intermediate product, a cumulative probability is calculated along with an increase in the demand amount for each final product and the requirement for each intermediate product, and the cumulative probability is calculated as the product. A basic holding amount determination step for determining a demand amount for each final product and a required amount for each intermediate product, which are different surplus probabilities, as a basic holding amount for each final product and a basic holding amount for each intermediate product; Based on the basic possession amount for each final product or each intermediate product and the product link information, the subordinate final product or intermediate product linked to the intermediate product from the basic possession amount of the intermediate product for each intermediate product. A holding amount correction step of correcting the basic holding amount for each intermediate product by reducing the basic holding amount, and the determined basic holding amount for each final product and the corrected basic holding amount for each intermediate product, It is characterized by having an inventory amount to be held for each final product and a registered amount by product registration step for registering as an inventory amount to be held for each intermediate product.

  The inventory management program according to the present invention is an inventory for determining an inventory quantity of an intermediate product and an inventory quantity of a final product that should be held during the production process in a production line in which various final products are produced through a plurality of production processes. A product link information registration step for registering a high-order / low-order relationship in a manufacturing process as product link information for the final product and the intermediate product, and a probability of a demand amount expected for each final product. For each final product and the intermediate product, and the probability that inventory will not be allocated to demand for each final product and the intermediate product. The surplus probability by product registration step, the demand distribution by end product and the product link information are used to confirm the demand for each end product. Intermediate product required amount distribution calculating step for calculating a probabilistic distribution of the required amount for each intermediate product determined depending on the intermediate distribution as the intermediate product required amount distribution, the final product demand amount distribution and the intermediate product Based on the required amount distribution for each product, the cumulative probability is calculated along with the increase in the required amount for each final product and the required amount for each intermediate product, and the cumulative probability becomes the surplus probability for each final product. A basic holding amount determining step for determining a demand amount for each intermediate product and a required amount for each intermediate product as a basic holding amount for each final product and a basic holding amount for each intermediate product, and for each final product or each intermediate product Based on the basic holding amount and the product link information, the basic holding amount of the intermediate product is subtracted from the basic holding amount of the intermediate product for each intermediate product, and the basic holding amount of the subordinate final product or intermediate product is reduced. A holding amount correction step for correcting the basic holding amount for each inter-product, the determined basic holding amount for each final product and the corrected basic holding amount for each intermediate product for each final product A holding amount registration step for each product that is registered as a quantity and an inventory quantity to be held for each intermediate product, and is read out by a calculation unit in a computer to execute processing of each step.

  The inventory management apparatus according to the present invention uses an arithmetic unit of a computer, and in a production line in which various final products are manufactured through a plurality of manufacturing processes, the inventory amount and the final amount of intermediate products to be held during the manufacturing process. An inventory management apparatus for determining a stock quantity of a product, wherein a product link information registration unit for registering a high-order / low-order relationship in a manufacturing process as product link information for each of the final product and the intermediate product, For each of the final product and the intermediate product, the inventory is not allocated to demand, and there is a surplus. A surplus probability registration unit by product for registering the probability of end product as a surplus probability by product, and the stochastic amount of demand for each final product based on the demand distribution by end product and the product link information. Demand distribution distribution unit for each intermediate product that calculates a stochastic distribution of the required amount for each intermediate product determined depending on the cloth as a distribution distribution for each intermediate product, Demand distribution for each final product and each intermediate product Based on the required amount distribution, the cumulative probability along the increase in the demand amount for each final product and the required amount for each intermediate product is calculated, and the demand for each final product for which the cumulative probability becomes the surplus probability for each product. A basic holding amount determination unit that determines a quantity and a required amount for each intermediate product as a basic holding amount for each final product and a basic holding amount for each intermediate product, and a basic holding for each final product or each intermediate product Based on the quantity and the product link information, for each intermediate product, the basic holding amount of the intermediate product is subtracted from the basic holding amount of the lower final product or intermediate product linked to the intermediate product. Basic insurance A holding amount correction unit that corrects the amount, and the determined basic holding amount for each final product and the corrected basic holding amount for each intermediate product, the inventory amount to be held for each final product, and each intermediate product It has a product-specific possession amount registration unit that registers as an inventory amount to be retained.

According to this, the stock quantity of the intermediate product and the stock quantity of the final product to be held are determined by the following processes (1) to (8).
(1) The front / rear (upper / lower) relationship in the manufacturing process of the final product and intermediate product, and the intermediate product and other intermediate products is registered in the product link information. At this time, if the intermediate product has versatility, a plurality of final products or intermediate products are set below one intermediate product. In the manufacturing process, the upper order means the raw material, the lower order means the final product, and the intermediate product has a hierarchical structure from the upper order to the lower order. Having “” is called “link”.
(2) For the final product, the prospect of future demand is registered as a stochastic distribution of demand for the final product (demand distribution by final product).
(3) When the final product and intermediate product are held as inventory, if a large amount of inventory is held for actual demand that cannot be accurately predicted, a part or all of the inventory will not be allocated to the order. May be left over. This remaining probability (surplus probability) is registered for each final product and intermediate product.
(4) Next, the probability of the required amount for the intermediate product that is one higher than the final product, based on the upper / lower relationship between the intermediate product and the final product specified in the product link information and the distribution of demand for the final product. Distribution (required distribution by intermediate product) is calculated. Further, a probabilistic distribution of requirements for other intermediate products that are not directly linked to the final product (intermediate product requirement distribution) is calculated from the upper and lower relationships between the intermediate products.
(5) Then, a cumulative value of the probability with respect to an increase in the demand amount (required amount) is calculated based on the final product-specific demand amount distribution and the intermediate product required amount distribution obtained above. Furthermore, based on the cumulative probability for this demand amount (required amount), the inventory holding amount (basic holding amount) corresponding to the surplus probability set for each product (final product and intermediate product) Determined about the product. That is, the inventory holding amount (basic holding amount) when the remainder is generated with a predetermined probability is calculated for each product.
(6) Next, based on the product link information and the basic holding amount of each final product and intermediate product, the basic holding amount of the lower final product or intermediate product is determined from the basic holding amount of the upper intermediate product. By subtracting, the basic possession amount for each intermediate product is corrected. That is, the upper basic holding amount is corrected in consideration that a part of the inventory amount to be held at the upper level is held at the lower level.
(7) Finally, the basic holding amount for the final product and the corrected inventory holding amount for the intermediate product are registered and output for each product as the inventory amount to be finally held.
After that, production for securing a predetermined stock quantity is performed, and when an order is received, the lead time from the order to the shipment can be shortened by dispatching it to the stock. On the other hand, if there are fewer orders than expected, the inventory will remain.
Thus, given the probability distribution that is the expected demand for the final product, and the relationship between the intermediate product and the final product used to manufacture the final product, the surplus probability set for each final product and intermediate product is given. It is possible to quickly and easily calculate a satisfactory stock holding amount (a stock amount to be held for each final product and each intermediate product). Therefore, it is possible to adjust the balance between the surplus risk of inventory and the effect of shortening the delivery time from order receipt to shipment (corresponding to short delivery time) according to the demand characteristics of the final product. In addition, the product link information can handle the case where the intermediate product is used for the production of multiple final products or intermediate products. The amount can be determined. Furthermore, it is possible to easily obtain W satisfying “actual demand amount ≦ W” with the specified probability P 1. That is, it is possible to easily and quickly obtain the inventory holding amount = basic holding amount (corresponding to the above W) corresponding to the surplus probability (corresponding to the above P) set for each product.

  Here, in the inventory management method, the inventory management program, and the inventory management apparatus according to the present invention, the demand quantity distribution for each final product is the distribution of the demand quantity for each final product, the average demand quantity for each final product. The distribution of the required amount for each intermediate product is the distribution of the required amount for each intermediate product, the average of the required amount for each intermediate product = the demand amount of the lower final product or the intermediate product. And the variance of the requirements for each intermediate product- = the sum of the demand for the lower final product or the variance of the requirements for the intermediate product.

Thereby, even if the intermediate product has versatility that is used in a plurality of final products and other intermediate products, the distribution of the required amount of the intermediate product can be calculated extremely easily and in a short time.
Here, the variance of the required amount of the intermediate product = the sum of the demand amount of the lower final product or the variance of the required amount of the intermediate product is established when it is assumed that there is no correlation in the demand between the final products. In general, this assumption does not lose generality because the demands of different users can be considered independent.

  In the inventory management method, the inventory management program, and the inventory management device according to the present invention, the distribution of demand for each final product is a distribution of the demand for each final product, and the demand for each final product is a predetermined amount. It is registered as a frequency distribution based on a histogram divided by section, and the distribution distribution of the required amount for each intermediate product is obtained by combining the distribution of the required amount for each intermediate product from the combination of the sections of the demand amount of the lower final product. You may calculate as the histogram which calculated the frequency in the area of the required amount, and each said area.

  According to this, when it is difficult to give the demand distribution by end product with a specific distribution function such as normal distribution, uniform distribution, and gamma distribution, or when it is given as a frequency distribution originally like past orders received However, it is possible to calculate an appropriate inventory amount for each intermediate product and final product.

  The production plan creation program according to the present invention can be recorded and distributed on a fixed recording medium such as a removable recording medium or a hard disk, or via a communication network such as the Internet by wired or wireless telecommunication means. It can be distributed.

  The inventory management method, the inventory management program, and the inventory management apparatus according to the present invention have a hierarchical structure, and calculate an appropriate value of a general intermediate product that can be used for a plurality of final products and an inventory amount that the final product should have. can do.

It is a block diagram of the inventory management apparatus which concerns on this embodiment. It is the flowchart explaining the procedure of the process of the inventory management method which concerns on this embodiment. It is a figure which shows the product link information which concerns on a present Example. It is a figure which shows the basic possession quantity based on the required quantity distribution (cumulative probability) of the intermediate product which concerns on a present Example. It is an image figure which shows the calculation process of the stock amount of the whole product in a present Example. It is a figure which shows the basic possession amount based on the demand amount distribution (cumulative probability) of the final product which concerns on the modification of a present Example.

  Hereinafter, an embodiment for carrying out an inventory management method, an inventory management program, and an inventory management apparatus according to the present invention will be described based on a specific example with reference to the drawings.

  In addition, what is demonstrated below is only what was illustrated and does not show the application limit of the inventory management method and inventory management program which concern on this invention, and an inventory management apparatus. That is, the inventory management method, the inventory management program, and the inventory management apparatus according to the present invention are not limited to the following embodiments, and various modifications are possible as long as they are described in the claims. .

  First, an inventory management apparatus according to this embodiment will be described with reference to FIG. FIG. 1 is a block diagram of an inventory management apparatus according to this embodiment. The inventory management device 1 includes a calculation unit, a storage unit, an input unit, and an output unit, and is mounted on a computer. Here, each unit (calculation unit, storage unit, input unit, and output unit) of the inventory management apparatus 1 shown in FIG. 1 is configured by a computer such as a general-purpose personal computer. Such a computer stores hardware such as a CPU, ROM, RAM, hard disk, and CD-ROM drive, and the hard disk stores a program (this program is recorded on a removable storage medium). Can be installed on a variety of computers). And the above-mentioned each part is constructed | assembled by combining these hardware and software.

  As shown in FIG. 1, the inventory management device 1 includes product link information (product link information registration unit) 11, demand distribution by final product (demand distribution distribution by final product) 12, and surplus probability by product ( Product-specific surplus probability registration unit) 13, intermediate product requirement distribution 14, product-specific basic retention 15, product-specific retention 16, intermediate product requirement distribution calculation unit 21, and cumulative probability by demand The calculation unit 22 includes a basic possession amount determination unit 23 and a possession amount correction unit 24.

  Product link information 11 registers externally the front and back (upper / lower) relationships in the manufacturing process of final products and intermediate products, and intermediate products and other intermediate products for final products and intermediate products subject to inventory management. It is for memorizing. At this time, if the intermediate product has versatility, a plurality of final products or intermediate products are set below one intermediate product. In the manufacturing process, the upper order means the raw material, the lower order means the final product, and the intermediate product has a hierarchical structure from the upper order to the lower order. Having “” is called “link”. Here, the product link information 11 is input from an input unit (keyboard or the like) (not shown) at the start of inventory management, is recorded on a removable storage medium, is given, or is transmitted via wired or wireless telecommunication means such as the Internet. It is given via a communication network or stored in a storage device, an auxiliary storage device or the like.

  The final product demand distribution 12 is for registering and storing a probabilistic distribution of the expected demand in the future for each final product. The probabilistic distribution of the expected amount of demand expected in the future may be given by, for example, the average weight and variance (or standard deviation) obtained from past orders received as a normal distribution, or the demand as a histogram. The amount may be given by the probability of each section. Further, the demand distribution for each final product may be given as a stochastic distribution (probability distribution) such as a uniform distribution or a distribution function such as a gamma distribution, and is not limited to a normal distribution or a histogram. Here, the final product demand distribution 12 is input from an input unit (keyboard or the like) (not shown) at the start of inventory management, or recorded and given in a removable storage medium, or by wired or wireless telecommunication means. The data is given via a communication network such as the Internet and stored in a storage device, an auxiliary storage device, or the like.

  The surplus probability 13 for each product is for registering and storing a probability (excess probability) that the stock is not allocated to demand for each final product and intermediate product, and is registered from the outside. This is because, when holding the final product and the intermediate product as inventory, if a large amount of inventory is held for actual demand that cannot be accurately predicted, some or all of the inventory will not be allocated to the order. This is to cope with the fact that there may be a surplus. This surplus probability is determined in advance in consideration of loss (loss) when there is a surplus as stock and customer serviceability that can be delivered to stock after receiving an order and delivered in a short delivery time. Here, the product-specific surplus probability 13 is input from an input unit (keyboard or the like) (not shown) at the start of inventory management, is recorded in a removable storage medium, is given, or is connected to the Internet by wired or wireless telecommunication means. Or stored in a storage device, an auxiliary storage device, or the like.

  The required amount distribution calculation unit 21 for each intermediate product has a higher / lower relationship in the manufacturing process for the intermediate product and the final product registered in the product link information 11 and the final product registered in the demand distribution 21 for each final product. This is for calculating the stochastic distribution of the required amount for each intermediate product from the distribution of the stochastic demand amount for each and registering it as the required amount distribution 14 for each intermediate product. First, the required amount distribution calculation unit 21 for each intermediate product has a higher / lower relationship between the intermediate product registered in the product link information 11 and the final product, and the demand for each final product registered in the demand distribution 21 for each final product. From the quantity distribution, a probabilistic distribution of the required quantity for the intermediate product one level higher than the final product is calculated. Next, from the upper / lower relationship between intermediate products, there is a stochastic distribution of requirements for other intermediate products that do not link directly to the final product but are linked to the intermediate product that is one higher than the final product. Calculated. In this way, the stochastic distribution of requirements for other intermediate products that are not directly linked to the final product in a hierarchical structure is calculated.

Here, the required amount distribution 14 for each intermediate product when the final product-specific demand distribution 12 is given by a normal distribution or a histogram will be described below.
When the demand distribution by end product 12 is given as a normal distribution with average weight and variance (or standard deviation), the demand distribution by intermediate product 14 is also given as a normal distribution with average weight and variance (or standard deviation), The required amount distribution 14 for each intermediate product is calculated as follows.
Average weight of intermediate product requirements = average sum of demands of linked subordinate end products or average sum of subordinate intermediate products to link Variance of intermediate product requirements = demand of subordinate end products to link The variance of the intermediate product or the variance of the subordinate intermediate product to be linked Standard deviation of the intermediate product requirement = (the sum of the squares of the subordinate final product or intermediate product to be linked) ^1/2
This is true when it is assumed that there is no correlation in demand between the final products. In general, this assumption does not lose generality because the demands of different users can be considered independent.

Further, when the demand distribution 12 for each final product is given as a histogram with the probability for each section of demand, the demand distribution 14 for each intermediate product is also given as a histogram with the probability for each section of demand, and the demand for each intermediate product is required. The quantity distribution 14 is calculated as follows.
First, for all combinations of the demand level of the linked lower final product, calculate the weight range when the demand of the linked lower final product is totaled, and the frequency range is calculated as the frequency. Calculate the sum of the probabilities for the final product. Here, if there is the same section in the calculated demand amount section of the subordinate final product, the frequency is tabulated for each section.
Next, in the frequency of the aggregated demand amount for each section, since a part of the section overlaps, the section of the demand amount is made fine so as not to overlap, and the section is made continuous. At this time, the original frequencies may be aggregated after being proportionally distributed.
With the above method, the distribution of the required amount of the intermediate product used for the final product to be linked is expressed as a histogram.
Note that other intermediate products that are not directly linked to the final product having a hierarchical structure are obtained by calculation in the same manner as described above, based on the calculated probability for each section of the lower intermediate product to be linked.

  The basic possession amount determination unit 23 responds to an increase in the demand amount (required amount) calculated by the cumulative probability calculation unit 22 by demand amount based on the demand amount distribution 12 by final product and the requirement distribution 14 by intermediate product. Based on the cumulative probability value (cumulative probability), determine the final product demand amount and intermediate product requirement, and the basic product possession amount of the final product and intermediate product, where the cumulative probability is 13 by product. This is for registration as the basic possession amount 15 by product.

  Based on the product link information 11 and the basic product amount of the final product and the intermediate product determined by the basic product amount determination unit 23, the possession amount correction unit 24 determines the basic possession amount of the intermediate product for each intermediate product. Therefore, the basic holding amount of each intermediate product is corrected by subtracting the basic holding amount of the subordinate final product or intermediate product linked to the intermediate product. In other words, the holding amount of the upper intermediate product is corrected in consideration that a part of the inventory amount to be held by the upper intermediate product is held by the lower intermediate product and the final product.

The holding amount 16 for each product is the basic holding amount for each final product determined by the basic holding amount determination unit 23 and the basic holding amount for each intermediate product corrected by the holding amount correction unit 24. And it is for registering as possession stock quantity for every intermediate product.
The registered product-specific holding amount 16 may be output as a calculation result in the inventory management apparatus 1 to an output unit such as a display or a printer (not shown) via a result output unit (not shown).

Next, the processing procedure of the inventory management method according to the present embodiment will be described with reference to FIG. FIG. 2 is a flowchart illustrating a processing procedure of the inventory management method according to the present embodiment. Here, “product” in FIG. 2 means a combined expression of the final product and the intermediate product.
The process of the production plan creation method according to the present embodiment described below can be read and executed by the CPU as an inventory management program in the computer as well. The inventory management program can be installed in various computer storage devices by recording it in a removable storage medium.

  As shown in FIG. 2, in the computer, data on product link information, distribution of demand for each final product, and surplus probability for each product is input in advance from an input unit or recorded on a removable storage medium. Read by a wired or wireless telecommunication means via a communication network such as the Internet, and register it in the storage unit (S1: product link information registration step, final product demand amount distribution registration step, Product surplus probability registration step). This step corresponds to the product link information 11, the demand distribution 12 for each final product, and the surplus probability 13 for each product of the inventory management apparatus 1 described above, and detailed description thereof is omitted.

  Next, the stochastic distribution of the required amount for each intermediate product is calculated as the required product distribution for each intermediate product based on the data read in S1 (product link information and final product-specific demand distribution) (S2: intermediate product). Another requirement distribution calculation step). Note that this step corresponds to the required amount distribution calculation unit 21 for each intermediate product of the inventory management apparatus 1 described above, and a detailed description thereof will be omitted.

  Based on the demand distribution by end product read in S1 and the demand distribution by intermediate product calculated in S2, the cumulative probability associated with the increase in demand for the final product and the increase in the requirement for intermediate products. The cumulative probability is calculated, and the demand amount of the final product and the required amount of the intermediate product, which are the surplus probabilities for each product read in S1, are used as the basic possession amount of the final product and the basic possession amount of the intermediate product. Determine (S3: basic possession amount determination step). Note that this step corresponds to the cumulative probability calculation unit 22 for each demand amount, the basic possession amount determination unit 23, and the basic possession amount 15 for each product of the inventory management apparatus 1 described above, and detailed description thereof is omitted.

  Next, based on the basic possession amount of the final product determined in S3, the basic possession amount of the intermediate product, and the product link information read in S1, for each intermediate product, from the basic possession amount of the intermediate product, The basic holding amount of the intermediate product is corrected by subtracting the basic holding amount of the subordinate final product or intermediate product linked to the intermediate product (S4: holding amount correcting step). This step corresponds to the holding amount correction unit 24 of the inventory management apparatus 1 described above.

  Then, the basic possession amount for each final product determined in S3 and the basic possession amount for each intermediate product corrected in S4, the stock amount to be retained for each final product (retained stock amount) and the possession for each intermediate product It is registered as an inventory quantity (owned inventory quantity) to be output, and is output as a result of inventory management (S5: product-specific inventory registration step), and the process of the production plan creation method is terminated. Note that this step corresponds to the product holding amount 16 of the inventory management apparatus 1 described above.

  As described above, according to the inventory management device, the inventory management method, and the inventory management program of this embodiment, the probability distribution that is the expected amount of demand for the final product, the intermediate product that is used to manufacture the final product, and the final product Given product relationships, it is possible to quickly and easily calculate inventory holdings (stock quantities to be held for each final product and each intermediate product) that satisfy the surplus probability set for each final product and intermediate product. I can do it. Therefore, it is possible to adjust the balance between the surplus risk of inventory and the effect of shortening the delivery time from order receipt to shipment (corresponding to short delivery time) according to the demand characteristics of the final product. In addition, the product link information can handle the case where the intermediate product is used for the production of multiple final products or intermediate products. The amount can be determined. Furthermore, it is possible to easily obtain W satisfying “actual demand amount ≦ W” with the specified probability P 1. That is, it is possible to easily and quickly obtain the inventory holding amount = basic holding amount (corresponding to the above W) corresponding to the surplus probability (corresponding to the above P) set for each product.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims.

  Next, in order to explain specific examples of the inventory management apparatus, the inventory management method, and the inventory management program of the present embodiment, a simple example will be described below.

  First, based on FIG. 2, the procedure of the process of the inventory management method using the inventory management apparatus which concerns on a present Example is demonstrated.

  In this embodiment, in the computer, the product link information shown in Tables 1 and 2 and FIG. 3, the demand distribution by final product shown in Table 3, and the data on the surplus probability by product shown in Table 4, It is input from the input unit, recorded in a removable storage medium, given, or given via a communication network such as the Internet by wired or wireless telecommunication means, and is read and registered in the storage unit (S1) .

  Here, as shown in Tables 1 and 2, the product link information of the present embodiment is assumed to have four types of final products A to D, three types of intermediate products 1 to 3, and one type of raw material. . The product link information includes the relationship from the lower product shown in Table 1 (meaning the final product, intermediate product, or raw material; the same applies to the following description) to the higher product, and the upper product shown in Table 2. Consists of relationships from products to subordinate products. For example, the upper intermediate product of the final product C is the intermediate product 2, and the lower products of the intermediate product 1 are the final products A and B. Further, the upper part of the intermediate product 3 is a raw material, and these relationships are shown in FIG. That is, the intermediate product 3 is used as a material for the intermediate product 1 and the intermediate product 2, and the intermediate product 1 is used as a material for the final product A and the final product B.

  Here, as shown in Table 3, the distribution of demand for each final product according to the present embodiment is the distribution of demand for each final product, for example, the average weight [ton] and the standard deviation obtained from the actual orders received in the past month. In the present embodiment, it is assumed that all are normal distributions.

  Here, as shown in Table 4, the surplus probability for each product of the present embodiment is given in the range of 20% to 40% for each product (intermediate product, final product). For example, the surplus probability of the intermediate product 2 is 30%, which means that the inventory of the intermediate product 2 is not allocated to the order with a probability of 30% against the uncertainty of demand given in Table 3. It shows that the intermediate product 2 is in stock.

  Next, based on the product link information (Tables 1 and 2) read in S1 and the demand distribution by final product (Table 3), the stochastic distribution of the requirements for each intermediate product is defined as the requirements distribution by intermediate product. Calculate (S2). Table 5 shows the calculation result of the required amount distribution for each intermediate product in this example.

As shown in Table 5, for example, since the intermediate product 2 is used for the final product C and the final product D, the average and standard deviation of the required amount are calculated as follows.
(Example of intermediate product 2)
Average: Final product C and final average sum standard deviations of the product D :( final product C the standard deviation of ² + the final product standard deviation ² of D) ^1/2

  Then, based on the demand distribution by final product (Table 3) read in S1 and the demand distribution by intermediate product (Table 5) calculated in S2, the cumulative probability and intermediate with the increase in demand of the final product are calculated. The cumulative probability associated with the increase in the required amount of the product is calculated, and the final product demand amount and the intermediate product required amount for which the cumulative probability becomes the surplus probability for each product (Table 4) read in S1 are determined as the final product. Are determined as the basic holding amount and the basic holding amount of intermediate products (S3). FIG. 4 shows the cumulative probability of the intermediate product 1 in this embodiment. Next, from this result, a demand amount (required amount) is obtained in which the cumulative probability becomes the probability set by the surplus probability for each product (Table 4). The demand amount (holding amount) obtained as a result is set as the basic holding amount of inventory for each product. In the example of FIG. 4, a required amount corresponding to 30% (from Table 4), which is the surplus probability set for the intermediate product 1, is obtained (about 44.6 [ton]). That is, it is shown that the stock amount of the intermediate product 1 in which the probability of remaining inventory of the intermediate product 1 is 30% is 44.6 tons. Table 6 shows the determination results of the basic amounts of remaining intermediate products and final products calculated in the same manner.

  Next, based on the basic holding amount of the final product determined in S3, the basic holding amount of the intermediate product (Table 6), and the product link information (Tables 1 and 2) read in S1, for each intermediate product, The basic holding amount of the intermediate product is corrected by subtracting the basic holding amount of the subordinate final product linked to the intermediate product or the basic holding amount of the subordinate intermediate product linked to the intermediate product from the basic holding amount of the intermediate product (S4). In the present embodiment, as shown in FIG. 3, since the links between products have a hierarchical structure, the basic possession amount of the intermediate product calculated in S3 is the basic possession of the final product or another intermediate product located below it. It is necessary to subtract the amount. In other words, since a part of the basic possession that should be retained at the upper level is held at the lower level, it is necessary to make corrections to eliminate duplication. The rightmost column of Table 7 shows the calculation result of the retained amount after correction. For example, since the intermediate products 3 are the intermediate product 1 and the intermediate product 2, the intermediate product 1 has a basic possession amount (44.6 [ton]) to an intermediate product 1 basic possession amount (44.6). [ton]) and the basic holding amount (82.6 [ton]) of the intermediate product 2 are subtracted 11.7 [ton] as the holding amount after correction. The final product has no subordinate product, so no correction is necessary.

  Then, the basic holding amount for each final product determined in S3 and the basic holding amount for each intermediate product corrected in S4 (Table 7), the inventory amount (holding inventory amount) to be held for each final product and the intermediate holding amount The product is registered as a stock amount (held stock amount) to be held for each product, output as a result of inventory management (S5), and the process of the production plan creation method is terminated. In this way, the stock quantity for all final products and intermediate products is determined. For reference, FIG. 5 shows an image diagram showing the calculation process of the inventory amount of the entire product in this embodiment.

  In this way, in this embodiment, given the probability distribution that is the expected amount of demand for the final product, and the relationship between the intermediate product and the final product used to manufacture the final product, for each final product and intermediate product. It is possible to quickly and easily calculate the inventory holding amount (the inventory amount to be held for each final product and each intermediate product) that satisfies the set surplus probability. Therefore, it is possible to adjust the balance between the surplus risk of inventory and the effect of shortening the delivery time from order receipt to shipment (corresponding to short delivery time) according to the demand characteristics of the final product. In addition, the product link information can handle the case where the intermediate product is used for the production of multiple final products or intermediate products. The amount can be determined. Furthermore, it is possible to easily and quickly obtain inventory holding amount = basic holding amount (corresponding to W above) corresponding to the surplus probability (corresponding to P above) set for each product.

  Therefore, the inventory management apparatus, inventory management method, and inventory management program of this embodiment form a hierarchical structure and can be used for a plurality of final products. It can be seen that the value can be calculated.

  In the present embodiment, the final product demand distribution is given in S1 as a normal distribution (Table 3) using the mean and variance as parameters. As modifications of the present embodiment, Tables 8 and 9 are used. As shown, it may be given as a histogram for each segment of demand. In the examples of Tables 8 and 9, the frequencies of the two types of final product A and final product B are registered with a probability (%) in units of 10 tons.

When the final product demand amount distribution is given as a histogram, in S2, the demand amount distribution of the intermediate product used in common for the final product A and the final product B can be calculated by the following method.
For all combinations (16 types) of the demand amount sections of final product A and final product B (4 types each), calculate the weight range when the demand amounts of final product A and final product B are totaled. As the frequency, the sum of the probabilities of the final product A and the final product B is calculated. Table 10 shows the results.

In Table 10, the upper part of each column represents the weight section [ton], and the lower part represents (probability%). And for example,
Product A: 20 to 30 tons, probability = 30%
Product B: 30 to 40 tons, probability = 10%
In this case, the range of the weight of the intermediate product that is commonly used in the final product A and the final product B is the sum of the minimum weight of the final product A and the minimum weight of the final product B. The range is up to the sum of the maximum weights of B, and the frequency is the frequency of the final product A + the frequency of the final product B. In other words,
Final product A + final product B: 50 to 70 tons, frequency = 40
It becomes.

  Since there is the same section in the section (16 types) of the demand amount of the final product A + the final product B calculated above, the frequency is tabulated for each section. Table 11 shows the results. For example, since there are two sections (frequency = 40 and 50) in Table 10, the frequency of 50 to 70 tons is 90 in Table 11.

  In the frequency of the demand amount aggregated above by section, since a part of the section overlaps, the demand amount section is made fine so as not to overlap, and the section is made continuous. Table 12 shows the results. In Table 12, the overlap is eliminated by reducing the width of the section to ½. Further, the frequencies shown in the original table 11 are totalized after being proportionally distributed.

  As described above, the distribution of the demand amount (required amount) of the intermediate product used for the final product A and the final product B can be expressed as a histogram.

  FIG. 6 (example for product A) shows an example of the cumulative probability calculated in S3 when the distribution of the demand amount by final product in S1 and the distribution of required amount by intermediate product in S2 is given as a histogram. . As can be seen from FIG. 6, the histogram is a line graph, but it can be used for calculation of the basic possession amount as in the normal distribution of FIG. 4, so that S <b> 3 and subsequent steps are performed along the processing flow of FIG. 2. Thus, it is possible to calculate the stock amount of all final products and intermediate products.

  As described above, even when the distribution of the demand amount of the final product is given as a histogram, it is possible to determine the stock amount of all the final products and intermediate products.

1 Inventory Management Device 11 Product Link Information (Product Link Information Registration Department)
12 Demand distribution by end product (Demand distribution distribution by end product)
13 Surplus probability by product (excess probability registration by product)
14 Distribution of required amount by intermediate product 15 Basic holding amount by product 16 Holding amount by product (holding register by product)
21 Requirement distribution calculation unit by intermediate product 23 Basic possession amount determination unit 24 possession amount correction unit S1 Product link information registration step, final product demand amount distribution registration step, product surplus probability registration step S2 Intermediate product requirement distribution calculation Step S3 Basic holding amount determination step S4 Holding amount correction step S5 Holding amount registration step by product

Claims (9)

In a production line in which various final products are manufactured through a plurality of manufacturing processes, an inventory management method for determining an inventory quantity of intermediate products and an inventory quantity of final products to be held during the manufacturing process,
The processing executed by the computing unit of the computer is
A product link information registration step for registering the upper and lower relationships in the manufacturing process as product link information for the final product and the intermediate product;
A final product demand amount distribution registration step of registering a stochastic distribution of the demand amount expected for each final product as a final product demand amount distribution;
For each final product and intermediate product, a product-specific surplus probability registration step of registering a probability that inventory is not allocated to demand and remaining as a product-specific surplus probability;
Based on the demand distribution for each final product and the product link information, the probability distribution of the requirements for each intermediate product determined depending on the stochastic distribution of the demand for each final product A requirement distribution calculation step for each intermediate product to be calculated as a quantity distribution;
Based on the distribution of demand for each final product and the distribution of requirements for each intermediate product, the cumulative probability is calculated along with the increase in the demand for each final product and the requirement for each of the intermediate products. A basic holding amount determining step for determining a demand amount for each final product and a required amount for each intermediate product, which are surplus probabilities by product, as a basic holding amount for each final product and a basic holding amount for each intermediate product;
Based on the basic possession amount for each final product or each intermediate product and the product link information, the subordinate final product or intermediate product linked to the intermediate product from the basic possession amount of the intermediate product for each intermediate product. A holding amount correction step of correcting the basic holding amount of each intermediate product by reducing the basic holding amount of
Products that register the determined basic holding amount for each final product and the corrected basic holding amount for each intermediate product as the inventory amount to be held for each final product and the inventory amount to be held for each intermediate product Separate holding amount registration step,
An inventory management method characterized by comprising: The demand distribution by final product registers the distribution of demand for each final product as an average and variance of the demand for each final product, and
The distribution of the required amount for each intermediate product is the distribution of the required amount for each intermediate product: the average of the required amount for each of the intermediate products = the sum of the demand amount of the lower final product or the average of the required amount of the intermediate product The inventory management method according to claim 1, wherein the variance of the required amount for each intermediate product is calculated as the sum of the demand amount of the lower final product or the variance of the required amount of the intermediate product. The demand distribution for each final product is registered as a frequency distribution by a histogram obtained by dividing the distribution of demand for each final product by a predetermined section of the demand for each final product,
The distribution distribution of the required amount for each intermediate product is obtained by calculating the distribution of the required amount for each intermediate product from the combination of the sections for the demand amount of the lower final product, and the frequency of the required amount of the intermediate product and the frequency in each section. The inventory management method according to claim 1, wherein the inventory management method is calculated as a calculated histogram. In a production line in which various final products are manufactured through a plurality of manufacturing processes, an inventory management program for determining an inventory quantity of intermediate products and an inventory quantity of final products to be held during the manufacturing process,
A product link information registration step for registering the upper and lower relationships in the manufacturing process as product link information for the final product and the intermediate product;
A final product demand amount distribution registration step of registering a stochastic distribution of the demand amount expected for each final product as a final product demand amount distribution;
For each final product and intermediate product, a product-specific surplus probability registration step of registering a probability that inventory is not allocated to demand and remaining as a product-specific surplus probability;
Based on the demand distribution for each final product and the product link information, the probability distribution of the requirements for each intermediate product determined depending on the stochastic distribution of the demand for each final product A requirement distribution calculation step for each intermediate product to be calculated as a quantity distribution;
Based on the distribution of demand for each final product and the distribution of requirements for each intermediate product, the cumulative probability is calculated along with the increase in the demand for each final product and the requirement for each of the intermediate products. A basic holding amount determining step for determining a demand amount for each final product and a required amount for each intermediate product, which are surplus probabilities by product, as a basic holding amount for each final product and a basic holding amount for each intermediate product;
Based on the basic possession amount for each final product or each intermediate product and the product link information, the subordinate final product or intermediate product linked to the intermediate product from the basic possession amount of the intermediate product for each intermediate product. A holding amount correction step of correcting the basic holding amount of each intermediate product by reducing the basic holding amount of
Products that register the determined basic holding amount for each final product and the corrected basic holding amount for each intermediate product as the inventory amount to be held for each final product and the inventory amount to be held for each intermediate product Separate holding amount registration step,
The inventory management program is characterized in that a computer reads the data by a calculation unit and causes each step to be executed. The demand distribution by final product registers the distribution of demand for each final product as an average and variance of the demand for each final product, and
The distribution of the required amount for each intermediate product is the distribution of the required amount for each intermediate product: the average of the required amount for each of the intermediate products = the sum of the demand amount of the lower final product or the average of the required amount of the intermediate product 5. The inventory management program according to claim 4, wherein the distribution of the required amount for each intermediate product is calculated as the sum of the demand amount of the lower final product or the distribution of the required amount of the intermediate product. The demand distribution for each final product is registered as a frequency distribution by a histogram obtained by dividing the distribution of demand for each final product by a predetermined section of the demand for each final product,
The distribution distribution of the required amount for each intermediate product is obtained by calculating the distribution of the required amount for each intermediate product from the combination of the sections for the demand amount of the lower final product, and the frequency of the required amount of the intermediate product and the frequency in each section. The inventory management program according to claim 4, wherein the inventory management program is calculated as a calculated histogram. Inventory management that determines the inventory quantity of intermediate products and the inventory quantity of final products to be held during the production process in a production line in which various final products are produced through a plurality of production processes using a calculation unit of a computer A device,
For the final product and the intermediate product, a product link information registration unit for registering the upper / lower relationship in the manufacturing process as product link information;
A demand distribution distribution unit by final product for registering the stochastic distribution of demand expected for each final product as a demand distribution by final product;
For each of the final product and the intermediate product, a surplus probability registration unit by product for registering a probability that inventory is not allocated to demand as a surplus probability by product,
Based on the demand distribution for each final product and the product link information, the probability distribution of the requirements for each intermediate product determined depending on the stochastic distribution of the demand for each final product A requirement distribution calculation unit for each intermediate product that is calculated as a quantity distribution,
Based on the distribution of demand for each final product and the distribution of requirements for each intermediate product, the cumulative probability is calculated along with the increase in the demand for each final product and the requirement for each of the intermediate products. A basic possession amount determination unit that determines a demand amount for each final product and a required amount for each intermediate product as a surplus probability for each product, as a basic possession amount for each final product and a basic possession amount for each intermediate product;
Based on the basic possession amount for each final product or each intermediate product and the product link information, the subordinate final product or intermediate product linked to the intermediate product from the basic possession amount of the intermediate product for each intermediate product. A holding amount correction unit that corrects the basic holding amount of each intermediate product by reducing the basic holding amount of
Products that register the determined basic holding amount for each final product and the corrected basic holding amount for each intermediate product as the inventory amount to be held for each final product and the inventory amount to be held for each intermediate product Separate holding amount registration department,
An inventory management apparatus comprising: The demand distribution by final product registers the distribution of demand for each final product as an average and variance of the demand for each final product, and
The distribution of the required amount for each intermediate product is the distribution of the required amount for each intermediate product: the average of the required amount for each of the intermediate products = the sum of the demand amount of the lower final product or the average of the required amount of the intermediate product The inventory management apparatus according to claim 7, wherein the variance of the required amount for each intermediate product is calculated as the sum of the demand amount of the lower final product or the variance of the required amount of the intermediate product. The demand distribution for each final product is registered as a frequency distribution by a histogram obtained by dividing the distribution of demand for each final product by a predetermined section of the demand for each final product,
The distribution distribution of the required amount for each intermediate product is obtained by calculating the distribution of the required amount for each intermediate product from the combination of the sections for the demand amount of the lower final product, and the frequency of the required amount of the intermediate product and the frequency in each section. 8. The inventory management apparatus according to claim 7, wherein the inventory management apparatus is calculated as a calculated histogram.