JP2009104359A - Proper inventory calculation method and device, tendency decision method and device for demand of brand and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proper inventory calculation method for calculating proper inventory whose stockout rate is low even when the deviation of the demand of a brand is large. <P>SOLUTION: The proper inventory calculation means includes determining a sample acquisition date by sampling a plurality of dates for the number of net filling lead time days within a calculation object period; repeating processing to calculate the total value of result shipping amounts on each sample acquisition date; creating the probability distribution of total values from the total value calculated each time the processing is repeated; and calculating safety inventory and ordering point inventory fulfilling a requested service rate from the probability distribution. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an appropriate safety stock that fits within a specified allowable shortage rate based on input information such as planned shipment information of each brand, and an appropriate inventory calculation method and apparatus for calculating order point inventory, The present invention relates to a demand trend determination method and apparatus, and a program.

Conventionally, a proper stock calculation method for calculating safety stock and order point stock (also called order point) based on input information such as brand shipment information is known. Safety stock refers to the level of stock required to prevent missing items in anticipation of fluctuations in purchase and sales volume due to unforeseen factors, both domestically and externally. Further, the order point inventory means an inventory level determined in advance so that an inventory is ordered when the inventory level is reached. The reorder point stock is generally determined by taking into account the average lead time to stock procurement in the safety stock. For example, in a conventional technique, the following calculation formulas (1) and (2) are used to calculate the safety stock and the order point stock.

  The safety factor k in the above formula is determined from the distribution of shipments and the service rate RS. The service rate RS is calculated by RS = 1−RO (where RO is an allowable shortage rate). However, although there is no problem when the probability distribution of the shipping amount is a normal distribution, for example, there is no problem in many cases. There is also a method of automatically performing fitting with a mathematical distribution (for example, normal distribution, Weibull distribution, etc.) based on the shipment amount, and determining the safety coefficient k based on the fitting. However, even with this method, since fitting accuracy is often low, it is difficult to calculate a proper stock with high accuracy. Due to the above circumstances, the calculation formulas (1) and (2) often lead to excess or understocking.

Patent Document 1 describes a method for calculating order point inventory and safety inventory based on demand frequency and variable lead time. In the appropriate inventory calculation method described in Patent Document 1, since the demand frequency is added as a new parameter, it is considerably improved as compared with the calculation method based on the previous equation. However, even with this method, there is a problem that a stock having a large demand (shipment) amount in time is likely to cause a shortage due to a low estimate of safety stock and order point stock.
WO2004 / 022463

  In the present invention, in view of the above-described problems of the prior art, by adopting a method that further considers the characteristics of the shipment amount (demand), including brands with a large time bias in demand, within the specified allowable shortage rate. It is an object of the present invention to provide an appropriate inventory calculation method and apparatus for calculating safety stock that can be accommodated and order point inventory, a demand trend determination method and apparatus, and a program therefor.

In order to achieve the above object, in the first aspect, the present invention is based on the actual shipment amount of each date in the calculation target period and the allowable shortage rate stored in the storage device for each brand using the computer. A method for calculating the appropriate stock for each stock based on information including the calculated service rate, the replenishment lead time required for stock replenishment, and the guaranteed lead time allowed before shipment,
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and overlap multiple dates for the number of days of the net replenishment lead time within the calculation target period. Allowing for sampling and determining sample acquisition date;
Calculating a total value of actual shipments on the determined plurality of sample acquisition dates;
Repeating the step of determining the sample acquisition date and the step of calculating the total value, and creating a probability distribution of the total value from the total value calculated for each repetition;
There is provided a method for calculating an appropriate inventory, comprising: calculating a safety stock satisfying a required service rate and an order point inventory from the probability distribution of the total value.

According to the second aspect of the present invention, in the second aspect, the actual shipment amount of each date in the calculation target period, the service rate calculated from the allowable shortage rate, the stock, A method for determining a trend in demand for a brand based on information including a replenishment lead time required for replenishment and a guarantee lead time allowed before shipment,
The net replenishment lead time is calculated from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and multiple dates corresponding to the number of days of the net replenishment lead time are calculated by random sampling from the calculation target period. Selecting and determining the first sample acquisition date;
Calculating a total value (first total value) of actual shipment amounts on the determined plurality of first sample acquisition dates;
The step of determining the first sample acquisition date and the step of calculating the first total value are repeatedly performed, and the probability distribution of the first total value is calculated from the first total value calculated for each repetition. A step to create,
Randomly sampling one day from within the calculation target period to determine a sample acquisition period starting date;
Determining a second sample acquisition date corresponding to the number of net replenishment lead time days within a range of net replenishment lead time days consecutive from the sample acquisition period calculation date;
Calculating a total value (second total value) of actual shipments on the plurality of determined second sample acquisition dates;
From the second total value calculated each time the step of determining the sample acquisition period start date, the step of determining the second sample acquisition date, and the step of calculating the second total value are repeated. Creating a probability distribution of the second total value;
The first safety stock obtained from the probability distribution of the first total value is compared with the second safety stock obtained from the probability distribution of the second total value, and based on the result of the comparison, A method for determining a trend in demand for brands, comprising the step of determining a bias in the demand for brands.

According to the third aspect of the present invention, in the third aspect, the actual shipment amount of each date in the calculation target period stored in the storage device for each brand, the service rate calculated from the allowable shortage rate, and the replenishment necessary for inventory replenishment Based on information including lead time and guaranteed lead time allowed before shipment, a computer calculates a proper stock for each stock,
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and overlap multiple dates for the number of days of the net replenishment lead time within the calculation target period. Means to allow and sample and determine the sample acquisition date;
Means for calculating a total value of actual shipments on the determined plurality of sample acquisition dates;
The means for determining the sample acquisition date and the means for calculating the total value respectively input the total value calculated for each repetition by repeating the determination of the sample acquisition date and the calculation of the total value. A means for creating a probability distribution of
There is provided an appropriate inventory calculation apparatus comprising: a safety inventory that satisfies a required service rate and a means for calculating an order point inventory from the probability distribution of the total value.

According to the fourth aspect of the present invention, in the fourth aspect, the actual shipment amount of each date in the calculation target period stored in the storage device for each brand, the service rate calculated from the allowable shortage rate, and the replenishment necessary for inventory replenishment Based on information including a lead time and a guaranteed lead time allowed until shipment, the computer determines a trend in demand for the brand,
The net replenishment lead time is calculated from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and multiple dates corresponding to the number of days of the net replenishment lead time are calculated by random sampling from the calculation target period. Means for selecting and determining a first sample acquisition date;
Means for calculating a total value (first total value) of actual shipment amounts on the determined plurality of first sample acquisition dates;
The means for determining the first sample acquisition date and the means for calculating the first total value respectively perform the determination of the sample acquisition date and the calculation of the first total value to calculate each time the repetition is performed. Means for inputting a first total value and creating a probability distribution of the first total value;
Means for randomly sampling one day from within the calculation target period and determining a sample acquisition period start date;
Means for determining a sample acquisition date corresponding to the number of net replenishment lead time days within a range of net replenishment lead time days consecutive from the sample acquisition period calculation date;
Means for calculating a total value (second total value) of actual shipments on the plurality of determined second sample acquisition dates;
The means for determining the sample acquisition period start date, the means for determining the second sample acquisition date, and the means for calculating the second total value are respectively determined for the sample acquisition period start date and the sample acquisition. Means for repeatedly determining the day and calculating the second total value, inputting the second total value calculated each time, and creating a probability distribution of the second total value;
The first safety stock obtained from the probability distribution of the first total value is compared with the second safety stock obtained from the probability distribution of the second total value, and based on the result of the comparison, And a means for determining a trend in the demand for brands.

According to the fifth aspect of the present invention, in the fifth aspect, the actual shipment amount for each date stored in the storage device for each brand, the service rate calculated from the allowable shortage rate, and the replenishment necessary for inventory replenishment A program for an appropriate inventory calculation device comprising a computer that calculates an appropriate inventory for each brand based on information including a lead time and an assured lead time allowed before shipment, the computer comprising:
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and overlap multiple dates for the number of days of the net replenishment lead time within the calculation target period. Means to allow and sample and determine the sample acquisition date;
Means for calculating a total value of actual shipments on the determined plurality of sample acquisition dates;
The means for determining the sample acquisition date and the means for calculating the total value respectively input the total value calculated for each repetition by repeating the determination of the sample acquisition date and the calculation of the total value. A means for creating a probability distribution of
There is provided a program which is operated as a means for calculating a safety stock satisfying a required service rate and an order point stock from the probability distribution of the total value.

According to the sixth aspect of the present invention, in the sixth aspect, the actual shipment amount for each date stored in the storage device for each brand, the service rate calculated from the allowable shortage rate, and the replenishment necessary for inventory replenishment A program for a determination device comprising a computer for determining a trend in demand for brands based on information including a lead time and a guaranteed lead time allowed before shipment, the computer comprising:
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment from the calculation target period, and a plurality of dates corresponding to the number of days of the net replenishment lead time by random sampling. Means for selecting and determining a first sample acquisition date;
Means for calculating a total value (first total value) of actual shipment amounts on the determined plurality of first sample acquisition dates;
The means for determining the first sample acquisition date and the means for calculating the first total value respectively perform the determination of the sample acquisition date and the calculation of the first total value to calculate each time the repetition is performed. Means for inputting a first total value and creating a probability distribution of the first total value;
Means for randomly sampling one day from within the calculation target period and determining a sample acquisition period start date;
Means for determining a second sample acquisition date corresponding to the number of net replenishment lead time days within a range of net replenishment lead time days consecutive from the sample acquisition period calculation date;
Means for calculating a total value (second total value) of actual shipments on the plurality of determined second sample acquisition dates;
The means for determining the sample acquisition period start date, the means for determining the second sample acquisition date, and the means for calculating the second total value are respectively determined for the sample acquisition period start date and the sample acquisition. Means for repeatedly determining the day and calculating the second total value, inputting the second total value calculated each time, and creating a probability distribution of the second total value;
The first safety stock obtained from the probability distribution of the first total value is compared with the second safety stock obtained from the probability distribution of the second total value, and based on the result of the comparison, Provided is a program that is operated as a means for determining a bias in brand demand.

  According to the appropriate inventory calculation method, apparatus, and program thereof of the present invention, an appropriate safety stock that corresponds to a different demand bias for each brand, and that the shortage of the brand falls below the allowable shortage rate, and The ordering point inventory can be obtained, and the increase in cost due to excess inventory and the increase in shortage due to inventory shortage can be suppressed. Further, since the fitting process itself to the distribution of the shipping amount is not performed, there is an effect that the safety stock and the order point stock can be calculated without depending on the fitting accuracy as in the conventional method.

  In addition, according to the method, apparatus, and program for determining the demand bias of the brand of the present invention, the computer can determine whether the demand bias of each brand is large or small, so that inventory management according to it can be performed. Is possible. In particular, when the shipment performance of the brand is approximated by an existing probability distribution, the determination becomes easy.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of a factory production system including an appropriate inventory calculation system according to an embodiment of the present invention. The production system 10 calculates the appropriate stock (safety stock) and the order point stock based on the production management system (computer) 11 that generates the shipment information (shipment result information) of each brand and the generated shipment information. And an appropriate inventory calculation system (computer) 12 to be returned to the production management system 11. Each system (computer) operates with a program stored in advance. The appropriate inventory calculation system 12 is based on the input shipment information, and the appropriate inventory calculation unit 13 that calculates the safety stock and the order point inventory, and the calculated safety stock is verified by simulation based on the shipment information and the shipment results. And a storage device 15 for storing data received from the production management system 11, data set by the user, calculation formulas, data being calculated, data of calculation results, and the like.

FIG. 2 is a diagram showing input / output information of the appropriate inventory calculation unit 13. Information input to the appropriate inventory calculation unit 13 includes a shipment result D01, an allowable shortage rate D02, a replenishment lead time D03, and a guaranteed lead time D04 for each brand. The replenishment lead time D03 represents the time required from the start of the replenishment request until the brand is replenished, and the guaranteed lead time D04 represents the surplus time from the date of receipt of the order from the customer to the delivery date. It is known that the net replenishment lead time, which is a substantial lead time, is given by the following calculation formula.
Net replenishment lead time = replenishment lead time−guaranteed lead time Information output from the appropriate inventory calculation system is the safety stock D05 and the order point stock D06.

  FIG. 3 shows one of flowcharts of processing by the appropriate inventory calculation unit 13. When the processing by the system is started, first, one brand i (i = 1 to n) that is a target of appropriate inventory calculation is selected, and a loop related to the processing of this brand i is set (step S01). For the brand i, one of the appropriate inventory calculation processing routines employed in the present embodiment is executed. Each calculation processing routine executes one or more of the appropriate inventory calculation processing procedures # 1, # 2, and # 3 (step S02). Details of the appropriate inventory calculation processing procedures # 1 to # 3 will be described later. The user designates which of the appropriate inventory calculation processing routines is selected in advance. Alternatively, a condition may be given in advance and the computer may make a determination. When the appropriate stock (safety stock and ordering point stock) is calculated for the target stock i by the proper stock calculation processing routine, the loop by the stock i is canceled (step S03), and the next stock, for example, the stock (i + 1) is designated. Is done. When the loop process is completed for all brands 0 to n, the entire process is completed.

  FIG. 4 shows one flowchart of an appropriate inventory calculation processing routine by the appropriate inventory calculation unit 13. When the processing by the system is started, first, one brand i that is a target of appropriate inventory calculation is selected, and a loop related to the processing of this brand i is set (step S11). For the brand i, the temporary safety stock S1 and the temporary order point stock O1 are calculated by the proper stock calculation process # 1 (step S12). Next, the temporary safety stock S3 and the temporary order point stock O3 are calculated by the appropriate stock calculation process # 3 (step S13). Next, the sizes of the temporary safety stocks S1 and S3 are compared (step S14). If S1 ≦ S3, the process proceeds to step S15, and if not, the process proceeds to step S16.

  If S1 ≦ S3 holds in step S14, it is determined that the selected brand i has a large demand time bias. If S1 ≧ S3 holds, it is determined that the selected brand i has a small demand time bias. In step S15, the safety stock SS is determined as the temporary safety stock S3, and the ordering point stock OP is determined as the temporary ordering point stock O3. In step S16, the safety stock SS is determined as the temporary safety stock S1, and the ordering point stock OP is determined as the temporary ordering point stock O1. When the appropriate stock (safety stock and order point stock) is calculated for the target brand i, the loop by the brand i is canceled (step S17), and the next brand, for example, the brand (i + 1) is designated. When the loop process is completed for all brands 0 to n, the entire process of the appropriate inventory calculation process routine is completed.

  FIG. 5 shows another flowchart of the appropriate inventory calculation processing routine by the appropriate inventory calculation unit 13. When processing by the system is started, first, one brand i that is the target of appropriate inventory calculation is selected, and a loop related to the processing of this brand i is set (step S21). For the brand i, the temporary safety stock S1 and the temporary order point stock O1 are calculated by the proper stock calculation processing procedure # 1 (step S22). Next, the temporary safety stock S3 and the temporary order point stock O3 are calculated by the proper stock calculation processing procedure # 3 (step S23). Next, the sizes of the temporary safety stocks S1 and S3 are compared (step S24). If S1 ≦ S3, the process proceeds to step S25, and if not, the process proceeds to step S27.

  If S1 ≦ S3 holds in step S24, it is determined that the selected brand i has a large demand time bias. If S1 ≧ S3 holds, it is determined that the selected brand i has a small demand time bias. In step S25, the temporary safety stock S2 and the order point stock O2 are calculated by the proper stock calculation processing procedure # 2. Next, the safety stock SS is determined as the temporary safety stock S2, and the order point stock OP is determined as the order point stock O2 (step S26). In step S27, the safety stock SS is determined as the temporary safety stock S3, and the ordering point stock OP is determined as the temporary ordering point stock O3. Next, the loop by the brand i is canceled (step S28), and the next brand, for example, the brand (i + 1) is designated. When the loop process is completed for all brands 0 to n, the entire process is completed.

FIG. 6 shows a specific process of the above-described appropriate inventory calculation process procedure # 1. This calculation processing procedure # 1 may be used alone as one of the appropriate inventory calculation processing routines by the appropriate inventory calculation system. When the proper inventory calculation process procedure # 1 is selected and the process starts, the net replenishment lead time VL1 is calculated from the replenishment lead time DL1 and the guaranteed lead time RL1.
VL1 = DL1-RL1
(Step S31). If the value of VL1 is negative, VL1 = 0 is set. Next, from the target period of the shipping information, the number of VLs for one day is selected alone and randomly, allowing duplication, and set as the sample acquisition date. For the sample acquisition dates for the selected number of VL days, the total value of the shipping quantity for each date is calculated (step S32). Step S32 is repeated as many times as is sufficient to use the obtained data as a probability, and a probability distribution of the total shipment value as the obtained data is created (step S33). An example of the created probability distribution is shown in FIG. When the total value of the actual shipment amount for the number of days of net replenishment lead time is taken on the horizontal axis and the probability that the total value of the shipment amount appears on the vertical axis, the probability distribution as shown in the figure is obtained. Next, an average value Av of the actual shipment amount is obtained from this probability distribution as shown in the figure, and further, a shipment amount T1 giving (1-RO) × 100% tile value (where RO is an allowable shortage rate) is obtained. . Next, as shown in the figure, the safety stock S1 is calculated as S1 = T1-Av (step S34). Next, the order point inventory O1 is calculated by O1 = S1 + Av (step S35). In the present embodiment, the replenishment lead time and the guaranteed lead time are set to constant values, but these may be given by a probability distribution.

  FIG. 7 shows specific processing of the proper inventory calculation processing procedure # 2. This calculation processing procedure # 2 may be used alone as one of the appropriate inventory calculation processing routines by the appropriate inventory calculation system. When the proper stock calculation processing procedure # 2 is selected and the processing is started, the net replenishment lead time VL1 is calculated from the replenishment lead time DL1 and the guaranteed lead time RL1 by VL1 = DL1-RL1 (step S41). If the value of VL1 is negative, VL1 = 0 is set. Next, one day (date X) is randomly selected from the target period of the shipping information, and the date corresponding to the number of VL1 days is duplicated within the period from the selected date X to the (VL1-1) day. Forgive and select a single and random sample date. Next, for the selected sample acquisition dates corresponding to the number of VL days, the total of the shipment amount for each date is calculated (step S42). The process of step S42 is repeated a sufficient number of times, and a probability distribution of the total value of the shipping quantity is created in the same manner as in the example of process procedure 1 (step S43). Next, an average value Av of the probability distribution is calculated, and further, a shipment amount T1 giving a (1-RO) × 100% tile value (RO: allowable shortage rate) is obtained from the probability distribution, and the safety stock S2 is calculated as S2. = T1-Av (Step S44). Further, the order point stock O2 is calculated by O2 = S2 + Av (step S45). In the present embodiment, the replenishment lead time and the guaranteed lead time are constant values, but these may be given by a probability distribution.

  FIG. 8 is a flowchart showing specific processing in the proper inventory calculation processing procedure # 3. This calculation processing procedure # 3 may be used alone as one of the appropriate inventory calculation processing routines by the appropriate inventory calculation system. When the proper stock calculation processing procedure # 3 is selected and the processing is started, the net replenishment lead time VL1 is calculated from the replenishment lead time DL1 and the guaranteed lead time RL1 by VL1 = DL1-RL1 (step S51). . If the value of VL1 is negative, VL1 = 0 is set. Next, a random selection is made for one day (date X) from the target period of the shipping information, and the dates from the selected date X to the consecutive (VL1-1) day are selected as sample acquisition dates, and the selection is made. With respect to the sample acquisition dates corresponding to the number of VLs per day, the total of the shipping quantity for each date is calculated (step S52). The process of step S52 is repeated a sufficient number of times, and a probability distribution of the total value of the shipping amount is created in the same manner as in the example of process procedure 1 (step S53). Next, an average value Av of the probability distribution is calculated, a shipping amount T1 giving a (1−RO) × 100% tile value (RO: allowable shortage rate) is obtained from the probability distribution, and the safety stock S3 is calculated as S3 = T1. -Calculate with Av (step S54). Further, the order point stock O3 is calculated by O3 = S3 + Av (step S55). In the above embodiment, the replenishment lead time and the guaranteed lead time are set to constant values, but these may be given by a probability distribution.

  Each appropriate inventory calculation processing procedure # 1, # 2, # 3 is different in the method of sampling the sample acquisition date for sampling the actual shipment amount from the calculation target period. In the calculation processing procedure # 1, random sampling is repeated for the number of days of the net replenishment lead time from the calculation target period, and the sample acquisition date for the number of days of the net replenishment lead time is determined.

  In the appropriate inventory calculation processing procedures # 2 and # 3, when determining the sample acquisition date, first, one day from the calculation target period is randomly sampled to determine the sample acquisition period start date, and then the sample acquisition is performed. A sample acquisition date corresponding to the number of days of the net replenishment lead time is determined within the range of the number of days of the net replenishment lead time that continues from the period start date. At this time, in the proper inventory calculation processing procedure # 2, the number of times corresponding to the number of net replenishment lead time days is randomly sampled within the range of the number of net replenishment lead time days consecutive from the sample acquisition period calculation date. In addition, in the proper stock calculation processing procedure # 3, a date corresponding to the number of net replenishment lead time days consecutive from the sample acquisition period calculation date is simply determined as the sample acquisition date.

  The proper stock calculation processing procedure # 1 is used for stock management of brands for which the demand bias is not so large. The proper stock calculation processing procedure # 2 is used for stock management of brands with large demand bias. The proper inventory calculation processing procedure # 2 is used particularly in the future when a demand bias similar to that in the past can be expected, and inventory management within the stockout rate specified in this case is possible.

  In the appropriate inventory calculation processing routine shown in FIG. 4, a demand bias is determined for each brand, and it is automatically discriminated between a brand where the demand bias is not so large and a brand where the demand bias is large, and based on the result. Then, the appropriate inventory calculation processing procedure # 1 or the calculation processing procedure # 3 is executed. This is particularly effective when the bias in demand does not change even if the demand bias is large.

  In the appropriate inventory calculation processing routine shown in FIG. 5, the demand bias is determined for each brand, and it is automatically determined whether the demand bias is not so large or the brand with a large demand bias. Then, the appropriate inventory calculation processing procedure # 3 or the calculation processing procedure # 2 is executed. Compared to FIG. 4, inventory management on the safe side is possible.

  According to the appropriate inventory calculation apparatus of the above embodiment and the method implemented by the apparatus, since the deviation of demand for each brand can be determined from the actual shipping results, the algorithm can be adopted accordingly, Inventory management with a low rate becomes possible.

  Although not shown in the above embodiment, it is possible to combine all of the proper inventory calculation processing procedures # 1 to # 3. In this case, for example, the temporary safety stocks S1, S2, and S3 are compared with each other, and the overall brand is a brand with a small demand bias, a brand with a moderate demand bias, and a brand with a large demand bias. The appropriate inventory calculation processing procedures # 1, # 3, and # 2 are applied to each of the three.

  In the above-described embodiment, the appropriate inventory processing system (apparatus) has been described. However, the present invention also provides an apparatus and method for determining a demand bias used in this system. The demand bias determination apparatus and method according to the present invention compares two or more of the safety stocks S1, S2, and S3 created in the above embodiment with each other, and further adds a safety factor to the obtained safety stock. It can be applied to an appropriate inventory processing system that employs a technique such as correction such as multiplication or correction of order point inventory. The calculation target period can be arbitrarily selected as long as the shipping record is accumulated for the brand. In addition, it is preferable to accumulate shipment records each time while managing inventory to prepare for future inventory management.

  As mentioned above, although this invention was demonstrated based on the suitable embodiment, the appropriate stock calculation method and apparatus of this invention, the trend determination method and apparatus of a brand demand, and a program are limited only to the structure of the said embodiment. However, various modifications and changes made from the configuration of the above-described embodiment are also included in the scope of the present invention.

The block diagram of the production system of the factory containing the appropriate inventory calculation system which concerns on one Embodiment of this invention. The diagram showing the input-output data of the appropriate inventory calculation part shown in FIG. The flowchart which shows the process of the appropriate stock calculation part shown in FIG. The flowchart which shows an example of the appropriate inventory calculation process routine of FIG. The flowchart which shows another example of the appropriate stock calculation process routine of FIG. The flowchart which shows the calculation processing procedure # 1 of the appropriate stock used in FIG.4 and FIG.5. The flowchart which shows the calculation processing procedure # 2 of the appropriate stock used in FIG.4 and FIG.5. 6 is a flowchart showing a proper inventory calculation processing procedure # 3 used in FIGS. 4 and 5. The graph which illustrates the probability distribution of the total value of the actual shipment amount created in the embodiment.

Explanation of symbols

10: Production system 11: Production management system 12: Appropriate inventory calculation system 13: Appropriate inventory calculation unit 14: Safety stock verification unit 15: Storage device

Claims (13)

Using a computer, the actual shipment volume for each date stored in the storage device for each brand, the service rate calculated from the allowable shortage rate, the replenishment lead time required for inventory replenishment, and shipment A method for calculating the appropriate stock for each brand based on information including the guaranteed lead time allowed by
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and overlap multiple dates for the number of days of the net replenishment lead time within the calculation target period. Allowing for sampling and determining sample acquisition date;
Calculating a total value of actual shipments on the determined plurality of sample acquisition dates;
Repeating the step of determining the sample acquisition date and the step of calculating the total value, and creating a probability distribution of the total value from the total value calculated for each repetition;
A method for calculating an appropriate inventory, comprising: calculating a safety inventory satisfying a required service rate and an order point inventory from the probability distribution of the total value.   The method for calculating an appropriate inventory according to claim 1, wherein the step of determining the sample acquisition date randomly samples the number of times corresponding to the number of days of the net replenishment lead time within the calculation target period.   The step of determining the sample acquisition date includes a first step of randomly sampling one day from the calculation target period to determine a sample acquisition period start date, and the net replenishment lead continuous from the sample acquisition period start date. The method according to claim 1, further comprising a second step of determining the sample acquisition date within a range of time days.   The method according to claim 3, wherein the second step performs random sampling by the number of times corresponding to the number of net replenishment lead time days within the range of the number of net replenishment lead time days consecutive from the sample acquisition period calculation date.   The said 2nd step is a reasonable stock calculation method of Claim 3 which selects the date for the number of net replenishment lead time days continuous from the said sample acquisition period calculation day. Using a computer, the actual shipment volume for each date stored in the storage device for each brand, the service rate calculated from the allowable shortage rate, the replenishment lead time required for inventory replenishment, and shipment A method of determining a trend in demand for a brand based on information including a guaranteed lead time allowed by
The net replenishment lead time is calculated from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment. Select and determine the first sample acquisition date; and
Calculating a total value (first total value) of actual shipments on the determined plurality of first sample acquisition dates;
The step of determining the first sample acquisition date and the step of calculating the first total value are repeated, and a probability distribution of the first total value is created from the first total value calculated at each repetition. And steps to
Randomly sampling one day from within the calculation target period and determining a sample acquisition period starting date;
Determining a second sample acquisition date corresponding to the number of net replenishment lead time days within a range of net replenishment lead time days consecutive from the sample acquisition period calculation date;
Calculating a total value (second total value) of actual shipments on the determined plurality of second sample acquisition dates;
The step of determining the sample acquisition period start date, the step of determining the second sample acquisition date and the step of calculating the second total value are repeated, and from the second total value calculated for each repetition, Creating a probability distribution of the second total value;
The first safety stock obtained from the probability distribution of the first total value is compared with the second safety stock obtained from the probability distribution of the second total value, and based on the result of the comparison, Determining a bias in demand for the brand, and a method for determining a trend in the demand for the brand. A method for calculating an appropriate stock of the brand using the trend determination method for a brand demand according to claim 6,
In the step of determining the demand trend of the brand, if the first safety stock is larger than the second safety stock, the first safety stock is adopted, and the first safety stock is the second safety stock. A method for calculating an appropriate inventory, comprising the step of adopting the second safety inventory when the inventory is smaller than the safety inventory. Stored in the storage device for each brand, the actual shipment amount for each date in the calculation target period, the service rate calculated from the allowable shortage rate, the replenishment lead time required for inventory replenishment, and allowance before shipment Based on information including guaranteed lead time, the computer calculates a proper stock for each stock,
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and overlap multiple dates for the number of days of the net replenishment lead time within the calculation target period. Means to allow and sample and determine the sample acquisition date;
Means for calculating a total value of actual shipments on the determined plurality of sample acquisition dates;
The means for determining the sample acquisition date and the means for calculating the total value respectively input the total value calculated for each repetition by repeating the determination of the sample acquisition date and the calculation of the total value. A means for creating a probability distribution of
An appropriate inventory calculation apparatus comprising: a safety inventory that satisfies a required service rate and a means for calculating an order point inventory from the probability distribution of the total value. Stored in the storage device for each brand, the actual shipment amount for each date in the calculation target period, the service rate calculated from the allowable shortage rate, the replenishment lead time required for inventory replenishment, and allowance before shipment Based on information including guaranteed lead time, the computer is a determination device for determining the trend of brand demand,
The net replenishment lead time is calculated from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and multiple dates corresponding to the number of days of the net replenishment lead time are calculated by random sampling from the calculation target period. Means for selecting and determining a first sample acquisition date;
Means for calculating a total value (first total value) of actual shipment amounts on the determined plurality of first sample acquisition dates;
The means for determining the first sample acquisition date and the means for calculating the first total value respectively perform the determination of the sample acquisition date and the calculation of the first total value to calculate each time the repetition is performed. Means for inputting a first total value and creating a probability distribution of the first total value;
Means for randomly sampling one day from within the calculation target period and determining a sample acquisition period start date;
Means for determining a second sample acquisition date corresponding to the number of net replenishment lead time days within a range of net replenishment lead time days consecutive from the sample acquisition period calculation date;
Means for calculating a total value (second total value) of actual shipments on the plurality of determined second sample acquisition dates;
The means for determining the sample acquisition period start date, the means for determining the second sample acquisition date, and the means for calculating the second total value are respectively determined as the sample acquisition period start date, the second Means for repeatedly determining the sample acquisition date and calculating the second total value, inputting the second total value calculated for each repetition, and creating a probability distribution of the second total value; ,
The first safety stock obtained from the probability distribution of the first total value is compared with the second safety stock obtained from the probability distribution of the second total value, and based on the result of the comparison, A brand demand trend judging device comprising: means for judging a brand demand bias. A device for determining a trend of demand for a brand according to claim 9, comprising a device for calculating a proper stock of the brand,
When the means for determining the demand bias of the brand determines that the first safety stock is larger than the second safety stock, the first safety stock is adopted to judge the demand bias of the brand. When the means determines that the first safety stock is smaller than the second safety stock, an appropriate stock calculation apparatus comprising means for adopting the second safety stock. Stored in the storage device for each brand, the actual shipment amount for each date in the calculation target period, the service rate calculated from the allowable shortage rate, the replenishment lead time required for inventory replenishment, and allowance before shipment A program for a proper inventory calculation device comprising a computer for calculating a proper inventory for each brand based on information including a guaranteed lead time, the computer comprising:
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment, and overlap multiple dates for the number of days of the net replenishment lead time within the calculation target period. Means to allow and sample and determine the sample acquisition date;
Means for calculating a total value of actual shipments on the determined plurality of sample acquisition dates;
The means for determining the sample acquisition date and the means for calculating the total value respectively input the total value calculated for each repetition by repeating the determination of the sample acquisition date and the calculation of the total value. A means for creating a probability distribution of
A program which is operated as means for calculating a safety stock satisfying a required service rate and an order point stock from the probability distribution of the total value. Stored in the storage device for each brand, the actual shipment amount for each date in the calculation target period, the service rate calculated from the allowable shortage rate, the replenishment lead time required for inventory replenishment, and allowance before shipment A program for a determination apparatus comprising a computer for determining a trend in demand for brands based on information including a guaranteed lead time, the computer comprising:
Calculate the net replenishment lead time from the replenishment lead time required for stock replenishment and the guaranteed lead time allowed before shipment from the calculation target period, and a plurality of dates corresponding to the number of days of the net replenishment lead time by random sampling. Means for selecting and determining a first sample acquisition date;
Means for calculating a total value (first total value) of actual shipment amounts on the determined plurality of first sample acquisition dates;
The means for determining the first sample acquisition date and the means for calculating the first total value respectively perform the determination of the sample acquisition date and the calculation of the first total value to calculate each time the repetition is performed. Means for inputting a first total value and creating a probability distribution of the first total value;
Means for randomly sampling one day from within the calculation target period and determining a sample acquisition period start date;
Means for determining a second sample acquisition date corresponding to the number of net replenishment lead time days within a range of net replenishment lead time days consecutive from the sample acquisition period calculation date;
Means for calculating a total value (second total value) of actual shipments on the plurality of determined second sample acquisition dates;
The means for determining the sample acquisition period start date, the means for determining the second sample acquisition date, and the means for calculating the second total value are respectively determined as the sample acquisition period start date, the second Means for repeatedly determining the sample acquisition date and calculating the second total value, inputting the second total value calculated for each repetition, and creating a probability distribution of the second total value; ,
The first safety stock obtained from the probability distribution of the first total value is compared with the second safety stock obtained from the probability distribution of the second total value, and based on the result of the comparison, A program characterized by being operated as a means for determining a bias in brand demand. The program according to claim 12, wherein the computer includes:
When the means for determining the demand bias of the brand determines that the first safety stock is larger than the second safety stock, the first safety stock is adopted to judge the demand bias of the brand. When the means determines that the first safety stock is larger than the second safety stock, the program is operated as means for adopting the second safety stock.

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