JP2009173435A - Safety stock quantity calculation system and safety stock quantity calculation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate appropriate safe stock quantities considering arrival delay of commercial products. <P>SOLUTION: This system 1 for calculating safe stock quantities stores actual arrival quantity of commercial produces relative to quantity scheduled for arrival with respect to each day; calculates a differential value between the quantity scheduled for arrival and the actual arrival quantity as a first differential value with respect to each day within an evaluation period; executes a process with respect to each day within the evaluation period to calculate a value by accumulating the first differential values for procurement days as a first cumulative difference; calculates an average value of the first cumulative differences for the respective days within the evaluation period and a standard deviation value; and calculates the safe stock quantities of the commercial products with respect to the arrival delay by using the calculated average value of the first cumulative differences and the standard deviation value. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a safe stock quantity calculation system and a safe stock quantity calculation program for calculating a safe stock quantity of a product.

In the conventional product ordering process, the number of products in stock ahead is estimated for the product procurement period (number of procurement days) based on the current number of products expected to be consumed (demand forecast number) and the expected number of goods received. When the number is less than or equal to the sum of the planned consumption of the product and the number of safety stock, the product is ordered using the difference as the order quantity. More specifically, the current time is April 1, the procurement period is 4 days, the procurement period is ahead, that is, the planned consumption number of products on April 4 is 65, the day before the procurement period elapses, that is, April 3 If the number of items in stock at the time of day is 60 and the number of safety stocks is 10, in the conventional ordering process for products, even if 65 items are consumed on April 4, 10 items remain in safe stock. As of April 1, 15 items (5 for consumption and 10 for safety stock) are ordered.
JP-A-2005-306543

  Normally, merchandise is received as scheduled after the procurement period after placing an order, but in some cases, the arrival of merchandise may be delayed. However, in the conventional product ordering process, the safety stock number is set without taking into account the arrival delay of the product, so the safety stock number becomes inappropriate, such as excessive safety stock. was there.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a safety stock number calculation system and a safety stock number calculation program capable of calculating an appropriate safety stock number in consideration of arrival delay of goods. It is to provide.

  The safety stock quantity calculation system and the safety stock quantity calculation program according to the present invention memorize the number of actual arrivals with respect to the expected arrival number of goods for each day, and calculate the difference between the expected arrival quantity and the actual arrival number for each day in the evaluation period. Calculate and execute a process of calculating a difference value added for the number of days of procurement as a cumulative difference for each day in the evaluation period, and calculate an average value and a standard deviation value of the cumulative difference for each day in the evaluation period, The safety stock number of the product is calculated using the average value and the standard deviation value of the calculated cumulative difference.

  According to the safety stock quantity calculation system and the safety stock quantity calculation program according to the present invention, it is possible to calculate an appropriate safety stock quantity in consideration of the arrival delay of goods.

  A safety stock quantity calculation system 1 according to an embodiment of the present invention is configured by a general-purpose or dedicated information processing device such as a workstation. As shown in FIG. 1, a database 2, a scheduled arrival history storage unit 3, a consumption The scheduled history storage unit 4 and the safety stock quantity calculation unit 5 are provided as main components. The database 2 includes a procurement period master DB 6 that stores data on the number of days required for product procurement (procurement period) for each product, and an arrival schedule that stores data on the number of products scheduled to be received the day before the procurement period on a product and daily basis. A history DB 7, an arrival history DB 8 that stores data on the number of arrivals in units of goods and days, a consumption schedule history DB 9 that stores data on the number of scheduled consumptions in the days ahead of the procurement period, and consumption A consumption history DB 10 that stores data on the number of records in units of products and days, and a safety stock number storage DB 11 that stores data on the number of safety stocks for each product are provided.

  The arrival schedule history storage unit 3 acquires the procurement period data of each product from the procurement period master DB 6 by executing the computer program stored in the ROM by the CPU in the information processing apparatus. The scheduled arrival number of the product on the date is calculated on a daily basis, and the calculated scheduled arrival number data is stored in the arrival schedule history DB 7. The consumption schedule history storage unit 4 acquires the procurement period data of each product from the procurement period master DB 6 by executing the computer program stored in the ROM by the CPU in the information processing apparatus. The number of scheduled consumptions of the product on the date is calculated on a daily basis, and the calculated scheduled consumption number data is stored in the consumption schedule history DB 9. The safety stock quantity calculation unit 5 calculates the safety stock quantity of each product using the data stored in the database 2 by the CPU in the information processing apparatus executing a computer program stored in the ROM. Then, the calculated safety stock quantity data is stored in the safety stock quantity storage DB 11.

  The safety stock quantity calculation system 1 having such a configuration performs appropriate processing in consideration of the arrival delay of goods by executing the following difference value calculation processes (1) and (2) and the safety stock quantity calculation process. At the same time as calculating the number of safety stocks, it is prevented that the number of safety stocks exceeding the necessary amount is calculated when the planned consumption number is larger than the actual consumption number. Hereinafter, the operation of the safety stock quantity calculation system 1 when executing the difference value calculation process and the safety stock quantity calculation process will be described in detail with reference to the flowcharts shown in FIGS.

[Difference calculation process (1)]
The flowchart shown in FIG. 2 starts at a predetermined time on each day, and the difference value calculation process proceeds to the process of step S1. Note that the process of step S2 in this difference value calculation process does not necessarily have to be performed every day, and may be performed once for each day in the evaluation period when calculating the number of safety stocks.

  In the process of step S1, the arrival schedule history storage unit 3 calculates the expected arrival number of the product with the date earlier than the procurement period and stores it in the arrival schedule history DB 7. Specifically, when today's date is April 1 and the procurement period is 4 days, the arrival schedule history storage unit 3 calculates the number of arrivals scheduled for April 4 and stores it in the arrival schedule history DB 7. . Further, an information processing device (not shown) counts the number of arrivals of the day and stores it in the arrivals history log DB 8. Thereby, the process of step S1 is completed and a difference value calculation process progresses to the process of step S2.

  In the process of step S2, the safety stock quantity calculation unit 4 calculates the difference value (the expected arrival quantity-the actual arrival quantity) between the actual arrival quantity and the expected arrival quantity on that day as the arrival delay quantity (first difference value). Store in the safety stock quantity storage DB 11. Specifically, when today's date is April 1, the safety stock quantity calculation unit 4 calculates a difference value between the actual arrival quantity and the expected arrival quantity on April 1 and stores it in the safe stock quantity storage DB 11. To do. Thereby, the process of step S2 is completed and a series of difference value calculation processes are complete | finished.

[Difference calculation process (2)]
The flowchart shown in FIG. 3 starts at a predetermined time of each day, and the difference value calculation process proceeds to the process of step S11. Note that the process of step S12 in the difference value calculation process is not necessarily performed every day, and may be performed at once for each day in the evaluation period when calculating the safety stock quantity.

  In the process of step S11, the consumption schedule history storage unit 4 calculates the planned consumption number of the product with the date earlier than the procurement period and stores it in the consumption schedule history DB 9. Specifically, when today's date is April 1 and the procurement period is 4 days, the consumption schedule history storage unit 4 calculates the number of consumption scheduled for April 4 and stores it in the consumption schedule history DB 9. . In addition, an information processing device (not shown) counts the number of consumption records for the day and stores it in the consumption record history DB 10. Thereby, the process of step S11 is completed and a difference value calculation process progresses to the process of step S12.

  In the process of step S12, the safety stock quantity calculation unit 5 calculates the difference value (consumption actual number-consumed consumption number) between the actual consumption number and the expected consumption number on the day as the second difference value, and stores the safe stock quantity storage DB11. Store in. Specifically, when today's date is April 1, the safe stock quantity calculation unit 5 calculates a difference value between the actual consumption quantity and the planned consumption quantity on April 1 and stores it in the safe stock quantity storage DB 11. To do. Thereby, the process of step S12 is completed and a series of difference value calculation processes are complete | finished.

[Safety inventory calculation process]
The flowchart shown in FIG. 4 starts at the timing when the user instructs the calculation of the safety stock quantity via an input device (not shown), and the safety stock quantity calculation process proceeds to the process of step S21. When instructing the calculation of the safety stock quantity, the user also specifies a period (evaluation period) for evaluating the safety stock quantity. In addition, the safety stock quantity calculation process shown below is executed individually for each product.

  In the process of step S21, the safety stock quantity calculation unit 5 reads the first and second difference values for each day in the evaluation period from the safety stock quantity storage DB 11, and the read first second difference value. Are added for each procurement period to calculate the first and second cumulative differences for each day in the evaluation period. Specifically, when the procurement period is 4 days and the current date is April 1, the safety stock quantity calculation unit 5 performs the operation from April 4 to April 7 as shown in FIG. The sum of the first difference values (65 + 0 + 0 + 0 = 65) is calculated as the arrival delay accumulated difference (first accumulated difference) on April 4. When the evaluation period is 6 days, the safety stock quantity calculation unit 5 calculates the arrival delay cumulative difference for each day from April 4 to April 9, as shown in FIG. Similarly, as shown in FIG. 6, the safety stock quantity calculation unit 5 calculates the sum (10 + 5 + 0−5 = 10) of the second difference value from April 4 to April 7 as the fourth difference. Calculated as a cumulative difference of 2. When the evaluation period is 6 days, the safety stock quantity calculation unit 5 calculates the second cumulative difference for each day from April 4 to April 9, as shown in FIG. Thereby, the process of step S21 is completed and the safety stock quantity calculation process proceeds to the process of step S22.

  In the process of step S22, the safety stock quantity calculation unit 5 calculates the average value of the first and second cumulative differences calculated for each day by the process of step S21. Specifically, in the example shown in FIG. 5, the safe stock quantity calculation unit 5 calculates the average value of the arrival delay cumulative difference of each day from April 4 to April 9 ((65 + 0 + 5 + 15 + 15 + 15) / 6 = 19.2) is calculated. In the example shown in FIG. 6, the safety stock quantity calculation unit 5 calculates the average value of the second cumulative difference for each day from April 4 to April 9 ((10 + 5-5-5-10− 15) /6=-3.3) is calculated. In the example shown in FIG. 6, since there are many days (target dates: April 7th and 9th) when the planned consumption number is larger than the actual consumption number, the average value of the second cumulative difference is a negative value. Thereby, the process of step S22 is completed, and the safety stock quantity calculation process proceeds to the process of step S23.

  In the process of step S23, the safe stock quantity calculation unit 5 calculates the standard deviation of the first and second cumulative differences calculated for each day by the process of step S21. Specifically, in the example shown in FIG. 5, the safety stock quantity calculation unit 5 calculates the standard deviation (23.3) of the arrival delay cumulative difference of each day from April 4th to April 9th. To do. In the example shown in FIG. 6, the safety stock quantity calculation unit 5 calculates the standard deviation (9.3) of the second cumulative difference for each day from April 4th to April 9th. Thereby, the process of step S23 is completed, and the safety stock quantity calculation process proceeds to the process of step S24.

  In the process of step S24, the safety stock quantity calculation unit 5 calculates the average values and standard deviations of the first and second cumulative differences calculated by the processes of steps S22 and S23, respectively, by the following formulas (1) and (2 ) To calculate the safety stock quantity of goods against arrival delays and consumption fluctuations. Specifically, when the value of the safety coefficient α in the formulas (1) and (2) is 1.65, in the example shown in FIG. 5, the safety stock quantity calculation unit 5 considers the arrival delay from the formula (1). The calculated safety stock number is calculated as 57.6 (= 19.2 + 1.65 × 23.3). In the example shown in FIG. 6, the safety stock quantity calculation unit 5 calculates the safety stock quantity considering consumption fluctuation as 12.0 (= −3.3 + 1.65 × 9.3) from Equation (2). Then, the safety stock quantity calculation unit 5 outputs the sum 69.6 (= 57.6 + 12.0) of the safety stock quantity of the product with respect to the arrival delay and the safety stock quantity of the product with respect to the consumption fluctuation as the safety stock quantity of the product. Thereafter, the required order quantity on April 1 is determined in consideration of the safety stock quantity of the commodity output by the user. Thereby, a series of safety stock number calculation processing is completed.

Number of safety stock for delayed arrival = MAX (average value of first cumulative number (for 4 days) + safety factor α × standard deviation of first cumulative number (for 4 days), 0) (1)
Number of safety stocks against consumption fluctuation = MAX (average value of second cumulative number (for 4 days) + safety coefficient α x standard deviation of second cumulative number (for 4 days), 0) (2)
As is clear from the above description, the safety stock quantity calculation system 1 according to the embodiment of the present invention stores the number of actual arrivals with respect to the expected arrival quantity of goods every day, and the expected arrival quantity for each day within the evaluation period. The difference value of the actual number of arrivals is calculated as the first difference value, and the process of calculating the value obtained by adding the first difference value for the number of procurement days as the first cumulative difference is executed for each day in the evaluation period, and the evaluation The average value and standard deviation value of the first cumulative difference for each day within the period are calculated, and the safety stock quantity of the product against the arrival delay is calculated using the calculated average value and standard deviation value of the first cumulative difference. To do. According to such a configuration, the safety stock number can be calculated in consideration of the arrival delay of goods, so that it is possible to prevent the safety stock number from becoming inappropriate, for example, the safety stock becomes excessive.

  The safety stock quantity calculation system 1 according to the embodiment of the present invention stores the number of actual consumptions with respect to the planned consumption quantity of the product for each day, and calculates the difference value between the scheduled consumption quantity and the actual consumption quantity for each day in the evaluation period. 2 for each day in the evaluation period, and the second cumulative value is calculated for each day in the evaluation period. An average value and a standard deviation value of the cumulative difference are calculated, and a safety stock quantity of the product against consumption fluctuation is calculated using the calculated second average value and standard deviation value of the cumulative difference. According to such a configuration, when the planned consumption number is larger than the actual consumption number, the average value of the second cumulative difference becomes a negative value so that the safety stock number is calculated to be small. When the number is greater than the actual consumption number, it is possible to prevent the safety stock number from being calculated more than necessary, and to calculate the appropriate safety stock number. In addition, since the variation in the difference value between the actual consumption number and the planned consumption number is smaller than the variation in the actual consumption number, the safety stock number calculation system 1 according to the embodiment of the present invention uses the variation in the actual consumption number for safety. Compared to the method of calculating the stock quantity, the safe stock quantity can be appropriately calculated.

  In the above embodiment, as shown in FIG. 7, for the dates whose planned consumption number is greater than the actual consumption number (in the example shown in FIG. 7, the target dates are April 7, 9, and 11), The difference value of the planned consumption number may be zero. According to such a configuration, since the safety stock number is calculated only by the difference value when the actual consumption number is larger than the planned consumption number, even if the difference value distribution is uneven, Can be calculated correctly. In the above embodiment, instead of the average value and standard deviation value of the second cumulative difference, as shown in FIG. 8, the safety stock is calculated using the average value and standard deviation of the difference value between the actual consumption number and the planned consumption number. The number may be calculated. According to such a configuration, an appropriate number of safety stocks can be calculated even when the number of accumulated data is small.

  As mentioned above, although the embodiment to which the invention made by the present inventors was applied has been described, the present invention is not limited by the description and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it should be added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above embodiments are all included in the scope of the present invention.

It is a block diagram which shows the structure of the safe stock quantity calculation system used as embodiment of this invention. It is a flowchart figure which shows the flow of the difference value calculation process (1) used as embodiment of this invention. It is a flowchart figure which shows the flow of the difference value calculation process (2) used as embodiment of this invention. It is a flowchart figure which shows the flow of the safe stock quantity calculation process used as embodiment of this invention. It is a figure for demonstrating an example of the safety stock number calculation process with respect to the arrival delay based on this invention. It is a figure for demonstrating an example of the safety stock number calculation process with respect to the consumption fluctuation | variation which concerns on this invention. It is a figure for demonstrating the application example of the safety stock number calculation process which concerns on this invention. It is a figure for demonstrating the application example of the safety stock number calculation process which concerns on this invention.

Explanation of symbols

1: Safety stock number calculation system 2: Database 3: Arrival schedule history storage unit 4: Consumption schedule history storage unit 5: Safety stock number calculation unit 6: Procurement period master DB
7: Arrival schedule history DB
8: Arrival history DB
9: Consumption schedule history DB
10: Consumption result history DB
11: Safety stock quantity storage DB

Claims (4)

An actual arrival number storage unit for storing the actual arrival number for the expected arrival number of products every day;
With reference to the information stored in the arrival record number storage unit, the difference value between the scheduled arrival number and the arrival record number is calculated as the first difference value for each day in the evaluation period, and the first difference value is calculated. The process of calculating the value added for the number of procurement days as the first cumulative difference is executed for each day in the evaluation period, and the average value and the standard deviation value of the first cumulative difference in each day in the evaluation period are calculated. A safety stock quantity calculation system, comprising: a safety stock quantity calculation unit that calculates a safety stock quantity of a product against arrival delay using the calculated first cumulative difference average value and standard deviation value. In the safety stock number calculation system according to claim 1,
The planned consumption number storage unit that stores the planned consumption number of products with a date earlier than the procurement period every day,
A consumption record number storage unit for storing the consumption record number of the product every day,
The safety stock quantity calculation unit refers to information stored in the planned consumption number storage unit and the actual consumption number storage unit, and calculates a difference value between the actual consumption number and the planned consumption number for each day in the evaluation period. A process of calculating as a second difference value and calculating a value obtained by adding the second difference value for the number of procurement days as a second cumulative difference is performed for each day in the evaluation period, 2. Calculate the average value and standard deviation value of the cumulative difference of 2, calculate the safety stock quantity of the product against consumption fluctuations using the calculated average value and standard deviation value of the second cumulative difference, A safety stock quantity calculation system that calculates the sum of the safety stock quantity and the product safety stock quantity against consumption fluctuations as the product safety stock quantity. In the safety stock number calculation system according to claim 2,
The safety stock quantity calculation unit sets the second difference value of the day to zero for a day when the planned consumption quantity is greater than the actual consumption quantity, and the safety stock quantity calculation system is characterized in that it is zero. A process of storing the actual number of arrivals for the expected number of arrivals of goods in the arrival history number storage unit every day,
Referring to the information stored in the actual arrival number storage unit, the difference value between the actual arrival number and the expected arrival number is calculated for each day in the evaluation period, and the difference value is added by the number of procurement days. Is executed for each day in the evaluation period, the average value and the standard deviation value of the cumulative difference for each day in the evaluation period are calculated, and the calculated average value and standard deviation value of the cumulative difference are used. A safety stock quantity calculation program that causes a computer to execute a process of calculating a safety stock quantity of a product in response to arrival delay.

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