JP6506432B1 - Inventory management system and program - Google Patents

Abstract

[Problem] To provide an inventory management system and program capable of performing appropriate inventory management in accordance with sales transition for each product.
A stock management system (200) divides time series data of sales quantities of goods in a calculation basic period into a plurality of periods T1 to T4. The inventory management system 200 calculates an average value AVEall of sales quantities in the entire calculation base period, an average value AVEmax of sales quantities in the first period T1, an average value AVEmin of sales quantities in the second period T3, and a calculation base period The base period is determined to be the period T2 based on the latest sales volume Zrec at. The stock management system 200 calculates the number of safety stocks based on the sales volume in the period T2.
[Selected figure] Figure 4

Description

  The present invention relates to an inventory control system and program.

  Various inventory control systems are known. In a general system, numerical values such as "appropriate inventory number", "ordering point", "ordering lot" and the like are received from the user and operated based on these numerical values.

  Patent Document 1 describes a system for determining the order placement timing and the like of products according to the stock. This system can take into account seasonal variations in sales.

JP-A-11-296611

  However, in the conventional system, there has been a problem that it is not possible to carry out appropriate inventory management in accordance with sales transition for each product.

  For example, in a system in which a human inputs the appropriate stock quantity etc., it is difficult to set an appropriate numerical value, and there is no certainty whether the set numerical value is appropriate.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide an inventory management system and program capable of performing appropriate inventory management in line with sales transition for each product. Do.

In order to solve the above-mentioned problems, the stock management system according to the present invention is
The function of dividing time series data of the sales volume of goods in the calculation basic period into a plurality of periods,
The average value of the sales volume in the entire calculation basic period, the average value of the sales volume in the first period which maximizes the average value of the sales volume among all the periods, and the average value of the sales volume among all the periods A base period determination function of determining a base period based on the average value of the sales amount in the second period to be minimized and the latest sales amount in the calculated base period;
And a function of calculating the number of safety stocks based on the sales volume in the reference period ,
The reference period determination function
An average value AVEall of the sales volume over the calculated basic period,
An average value AVEmax of the sales volume in the first period,
The average value AVEmin of the sales volume in the second period,
About the latest sales volume Zrec in the said basic period,
When AVEmax <Zrec, the first period is determined as a reference period,
If AVEall <Zrec <AVEmax, a period corresponding to the smallest one of average values larger than Zrec is determined as a reference period,
When AVEmin <Zrec <AVEall, a period corresponding to the largest one of average values smaller than Zrec is determined as a reference period,
If Zrec <AVEmin, then the second period is determined as the reference period,
The function of calculating the number of safety stocks has the following formula:
Safety stock number = base stock number * safety factor * √ (ordering interval + lead time)
The safety stock number is calculated based on the following equation, where the base stock number is the sum of the average value of the sales volume in the base period and the standard deviation of the sales volume in the base period.
According to a specific aspect, the apparatus further comprises a function of calculating the quantity to be ordered based on the safety stock quantity and the current stock quantity ,
The function of calculating the quantity to be ordered is the following formula:
Quantity to be ordered = Base shipment quantity + Safety stock quantity-Current stock quantity
The quantity to be ordered is calculated, wherein the base shipment quantity is the average value of the quantity of sales in the base period or the quantity of sales in the base period to the average value of the quantity of sales in the base period Is the value obtained by adding the standard deviation of
Further, a program according to the present invention causes a computer to function as the above-described system.

  According to the present invention, since it is possible to determine the standard period to be the basis of inventory management in consideration of the sales volume in each of a plurality of periods, more appropriate inventory management can be performed in accordance with the transition of each product.

It is a figure which shows the example of a structure of the inventory management system which concerns on Embodiment 1 of this invention. It is a figure which shows the example of a structure of sales information of FIG. It is a figure which shows the example of a sales transition pattern. It is a flowchart explaining an example of operation | movement of the inventory management system of FIG. It is a figure which shows the example at the time of dividing | segmenting the time-sequential data of FIG. 2 into six periods.

Hereinafter, an embodiment of the present invention will be described based on the attached drawings.
Embodiment 1
FIG. 1 shows an example of the configuration of a stock management system 200 according to Embodiment 1 of the present invention. The stock management system 200 has a configuration as a known computer, and includes a processor 910 that performs processing such as calculation and a storage device 920 that stores information. The processor 910 is, for example, a CPU (central processing unit), and the storage unit 920 includes, for example, a memory and an auxiliary storage unit. A part of the memory may constitute a storage unit that stores information.

  The processor 910 may have a more detailed internal structure, and may include, for example (not shown) a data transceiver and a calculator.

  The storage unit 920 stores sales information 11. The storage device 920 also stores a program (not shown), which causes the computer to function as the stock management system 200.

  Further, the stock management system 200 includes an input interface 930 and an output interface 940. The input interface 930 includes, for example, a keyboard and a mouse, a network interface, and the like. Also, the output interface 940 includes, for example, a liquid crystal display, a printing apparatus, a network interface, and the like.

  An example of the configuration of the sales information 11 is shown in FIG. The sales information 11 includes time-series data of the quantity of goods sold in a certain period. The stock management system 200 determines the sales transition pattern based on the transition of the sales volume recorded in the sales information 11, and calculates the number of safe stocks of the product. Although only sales information of a specific product is shown in FIG. 2, sales information of a plurality of types of products may be similarly included, and in such a case, processing relating to inventory management can be executed for each product. Good.

  FIG. 3 shows an example of the sales transition pattern. The pattern P1 is considered to be a pattern corresponding to, for example, so-called "selling goods", as sales are steadily increasing. Similarly, pattern P2 is "trend product", pattern P3 is "mature product", pattern P4 is "product whose trend is leaving", pattern P5 is "transient product", and pattern P6 is "disappear. It can be considered that the product corresponds to the pattern corresponding to each.

  These patterns are important in predicting the quantity of goods sold. For example, with a product showing pattern P1 or P2, since large sales can be expected in the future, it can be considered preferable to carry out inventory management based on a period in which sales were relatively large in the past.

  With products that exhibit Pattern 3, sales are relatively stable, but it is possible that sales may decline in the future. With products that exhibit Pattern 4, sales have fallen and it is possible that sales may decline in the future. For this reason, it can be considered that it is preferable that inventory management be performed on the basis of a period in which sales were in the middle in the past, for a product having the pattern P3 or P4.

  In the products showing the pattern P5 or P6, since large sales can not be expected in the future, it can be considered that inventory management is preferably performed on the basis of a period in which sales were relatively small in the past.

  The pattern classification as shown in FIG. 3 is neither absolute nor unique. The effects of the present invention may be obtained even for patterns that do not fall under any of these.

  The inventory management system 200 selects one of the patterns shown in FIG. 3 based on the time-series data of sales quantities as shown in FIG. 2 and based on the selected pattern (more strictly, Have a function to perform inventory control) based on the sales volume in the period that should be the basis in the pattern.

  FIG. 4 shows a flowchart for explaining an example of the operation of the stock management system 200. First, the inventory management system 200 acquires time-series data of sales quantities of goods in a certain calculation basic period (step S1). “Calculated base period” means a specific period including sales to be taken as a basis for calculating the number of safety stocks, and in the first embodiment, the calculated base period is from December 2016 to November 2017. Set in 12 months.

  Next, the stock management system 200 divides the acquired time-series data (that is, time-series data in the calculated basic period) into a plurality of periods (step S2). Hereinafter, the term “period” in the present specification means each of the divided periods. For example, the calculated basic period consisting of 12 months from December 2016 to November 1717, period T1 (December 2016 to February 1717), period T2 (March to May 2017), period T3 (2017 Year (June-August), divided into a total of four periods T4 (September to November 2017). For example, the sales volume in July 2017 will be divided into period T3.

Next, the inventory management system 200 calculates a statistical quantity of sales volume for the calculated basic period and each divided period (step S3). The statistics calculated include the mean value. In the example of FIG. 2, the mean value is calculated as follows.
Calculated whole base period: Average value AVEall = (106 + 80 + 84 + 60 + 54 + 40 + 47 + 42 + 34 + 39 + 45 + 50) / 12 = 56.75
Period T1: Average value AVE1 = (106 + 80 + 84) / 3 = 90
Period T2: Average value AVE2 = (60 + 54 + 40) /3≒51.33
Period T3: Average value AVE3 = (47 + 42 + 34) / 3 = 41
Period T4: Average value AVE4 = (39 + 45 + 50) /3≒44.67

  Next, the stock management system 200 determines a reference period (step S4, reference period determination function). The base period means the period including the sales volume to be the basis of inventory management. For example, if a large sales can be expected in the future, it is preferable to set a period including a large sales volume (period T1 in the example of FIG. 2). Conversely, if a large sales can not be expected, a small sales volume is included. It can be said that a period (period T3 in the example of FIG. 2) is preferable.

  The reference period is determined based on each statistic calculated in step S3 and the latest sales volume (ie, the latest sales volume Zrec in the calculated base period). In the example of FIG. 2, Zrec corresponds to the sales volume in November 2017, and Zrec = 50. Although any method may be used to refer to these values in the determination of the reference period, an example is shown below.

  First, the inventory management system 200 sets the average value of the sales volume to the maximum (AVEmax) among all the periods (the first period), and sets the average value of the sales volume to all the periods from the all periods (AVEmin). Determine the one (the second period). In the above example, AVEmax = AVE1> AVE2> AVE4> AVE3 = AVEmin, so the first period is the period T1 for giving the average value AVE1, and the second period is the period T3 for giving the average value AVE3.

Then, the stock management system 200 determines the reference period by the following determination processing based on AVEall, AVEmax, AVEmin, and Zrec.
Case A: When AVEmax <Zrec. In this case, a period T1 corresponding to AVEmax = AVE1 is determined as a reference period. In this case, it can be considered that the sales transition pattern corresponds to the pattern P1 or P2 of FIG.
Case B: AVEall <Zrec <AVEmax. In this case, a period corresponding to the smallest one of the average values larger than AVEall is determined as the reference period. In this case, the sales transition pattern can be considered to correspond to the pattern P3 of FIG. For example, when the average value of period T2 = 60, the average value of period T3 = 70, and the average value of period T4 = 80 as an average value larger than AVEall, the period with the lowest average value among them is the reference period. Therefore, the period T2 is determined as the reference period.
Case C: AVEmin <Zrec <AVEall. In this case, the period corresponding to the largest one of the average values smaller than AVEall is determined as the reference period. In this case, it can be considered that the sales transition pattern corresponds to the pattern P4 of FIG. The case described using FIG. 2 corresponds to case C. The average value smaller than AVEall corresponds to the average value of period T2 ≒ 51.33, the average value of period T3 = 41, and the average value of period T4 ≒ 44.67, among which the period with the largest average value Is the reference period, the period T2 is determined as the reference period.
Case D: Zrec <AVEmin. In this case, a period T3 corresponding to AVEmin = AVE3 is determined as a reference period. In this case, it can be considered that the sales transition pattern corresponds to pattern P5 or P6 in FIG.

  In the example of FIG. 2, since AVEmin = AVE3 = 41 <Zrec = 50 <AVEall = 56.75, this corresponds to Case C, and the average value AVE1 = 90, AVE2 ≒ 51.33, AVE3 = 41, AVE4 ≒ 44. A period T2 corresponding to AVE2 ≒ 51.33, which is the largest one of average values smaller than AVEall = 56.75 among 67, is determined as a reference period.

  After determining the reference period in this manner, the inventory management system 200 calculates the number of safety stocks based on the sales volume in the reference period (step S5). Although this calculation method can be arbitrarily designed, it can be calculated based on, for example, the average value of the sales volume in the base period and the standard deviation of the sales volume in the base period. Alternatively, for example, it can be calculated based on the average value of the sales volume in the base period and the variance of the sales volume in the base period.

As a specific example, the following equation may be used. This equation takes into consideration the safety factor, the order interval, and the lead time, in addition to the mean value and the standard deviation.
Safety stock number = base stock number * safety factor * √ (ordering interval + lead time)
The base inventory quantity is the sum of the average value of the sales volume in the base period and the standard deviation of the sales volume in the base period. In the above-mentioned example, since the average value AVE2 ≒ 51.33 in the reference period T2 and the standard deviation is 8.4, the base inventory number is about 59.73. The safety factor is, for example, an arbitrary real number of 1 or more, for example 1.65. Assuming that the order interval is 23 days (23/30 0.7 0.77 in terms of monthly units) and the lead time is 7 days (7/30 0.2 0.23 months in terms of monthly units), safety stock The number is approximately 59.73 * 1.65 ** (0.77 + 0.23) ≒ 98.56.
The safety factor may be a numerical value less than one.

Next, the stock management system 200 calculates the number of recommended orderings, that is, the quantity to be ordered, based on the safety stock number and the current stock number (step S6). The quantity to be ordered may be, for example, simply a value obtained by subtracting the current number of stocks from the number of safety stocks, but it is preferable to use the following formula.
Quantity to be ordered = Base shipment number + Safety stock number-Current inventory number Base shipment number is, for example, the average value of the sales volume in the base period, to which the standard deviation or variance of the sales volume in the base period is added You may use the value which you

  The current inventory quantity may be stored, for example, in the storage device 920 of the inventory management system 200. Also, the current inventory number may be an actual inventory number or a logical inventory number calculated by some calculation.

  Next, the stock management system 200 outputs the quantity to be ordered (step S7). For example, on the display device, a message such as “How should I order the product XX? Xx?” Is displayed.

  As described above, according to the inventory management system 200 according to the first embodiment, it is possible to determine the standard period to be the basis of inventory management in consideration of the sales volume in each of the periods T1 to T4. More appropriate inventory management can be made in line with each trend.

The following modifications can be made in the first embodiment described above.
In the first embodiment, although time series data is divided into four periods, the number of divided periods does not have to be four, and is divided into two, three, six, twelve, etc. May be When the time series data of FIG. 2 is divided into 12 pieces, the data of each month becomes the average value of the corresponding period as it is, and the standard deviation becomes 0.

FIG. 5 shows an example in which time-series data is divided into six periods.
Calculated whole base period: Average value AVEall = 56.75
Period T11: Average value AVE11 = (106 + 80) / 2 = 93
Period T12: Average value AVE12 = (84 + 60) / 2 = 72
Period T13: Average value AVE13 = (54 + 40) / 2 = 47
Period T14: Average value AVE14 = (47 + 42) /2=44.5
Period T15: Average value AVE15 = (34 + 39) /2=36.5
Period T16: Average value AVE16 = (45 + 50) /2=47.5

  In this case, since AVEmax = AVE11 and AVEmin = AVE15, the first period is a period T11 giving an average value AVE11, and the second period is a period T15 giving an average value AVE15. Further, since AVEmin = AVE15 = 36.5 <Zrec = 50 <AVEall = 56.75, it corresponds to Case C, and among the average values AVE11 to AVE16, the maximum value among the average values smaller than AVEall = 56.75. A period T16 corresponding to AVE16 = 47.5, which is one of the above, is determined as a reference period. The subsequent calculation is the same as in the case of the above-described four division.

  The time series data to be divided into a plurality of time periods may not include the latest data (Zrec). For example, in the example of FIG. 2, the data of November 2016 to October 1717 may be divided into a plurality of periods without including the data of November 2017.

  Steps S6 and S7 may be omitted. For example, the stock management system 200 may output the number of safety stocks in step S5, and the user may perform stock management accordingly. As a specific inventory management, additional orders may be placed when the actual inventory falls below the safety inventory. Even in this case, since the safety stock number is determined based on the appropriate reference period, more appropriate stock management can be performed.

  The method of determining the number of safety stocks is not limited to that of the first embodiment. For example, the average value of the sales volume in the base period may be used as the number of safety stocks.

  The algorithm for determining the reference period is not limited to that of the first embodiment. In the first embodiment, the reference period is determined using the period giving the maximum average value and the period giving the minimum average value, but other periods (for example, a period giving an average value closer to the overall average) It may be used to determine the reference period.

  The hardware configuration unit can be arbitrarily changed. For example, the inventory management system 200 may be configured by a plurality of computers.

  200 Inventory management system (computer), T1 period (first period), T2 period (reference period), T3 period (second period), T11 period (first period), T15 period (second period) , T16 period (reference period).

Claims (3)

The function of dividing time series data of the sales volume of goods in the calculation basic period into a plurality of periods,
The average value of the sales volume in the entire calculation basic period, the average value of the sales volume in the first period which maximizes the average value of the sales volume among all the periods, and the average value of the sales volume among all the periods A base period determination function of determining a base period based on the average value of the sales amount in the second period to be minimized and the latest sales amount in the calculated base period;
And a function of calculating the number of safety stocks based on the sales volume in the reference period ,
The reference period determination function
An average value AVEall of the sales volume over the calculated basic period,
An average value AVEmax of the sales volume in the first period,
The average value AVEmin of the sales volume in the second period,
About the latest sales volume Zrec in the said basic period,
When AVEmax <Zrec, the first period is determined as a reference period,
If AVEall <Zrec <AVEmax, a period corresponding to the smallest one of average values larger than Zrec is determined as a reference period,
When AVEmin <Zrec <AVEall, a period corresponding to the largest one of average values smaller than Zrec is determined as a reference period,
If Zrec <AVEmin, then the second period is determined as the reference period,
The function of calculating the number of safety stocks has the following formula:
Safety stock number = base stock number * safety factor * √ (ordering interval + lead time)
Calculating the number of safety stocks, wherein the number of base stocks is a sum of an average value of sales quantities in the base period and a standard deviation of the sales quantities in the base period;
Inventory management system. It further has a function to calculate the quantity to be ordered based on the number of safety stock and the current number of stock ,
The function of calculating the quantity to be ordered is the following formula:
Quantity to be ordered = Base shipment quantity + Safety stock quantity-Current stock quantity
The quantity to be ordered is calculated, wherein the base shipment quantity is the average value of the quantity of sales in the base period or the quantity of sales in the base period to the average value of the quantity of sales in the base period Is the value obtained by adding the standard deviation of
The stock management system according to claim 1 . A program that causes a computer to function as the system according to claim 1 or 2 .

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