JP2009126621A - Proper inventory quantity determination system and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proper inventory quantity determination system which largely reduces a gap between a proper inventory quantity calculated with a procurement lead time as a fixed value and a proper inventory quantity in an actual situation, and can improve an accuracy of the proper inventory quantity for the actual situation. <P>SOLUTION: In the proper inventory quantity determination system, an inventory pseudo calculation part 20 performs simulation of an inventory quantity transition based on the proper inventory quantity as the primary plan obtained based on various parameter PM1 including a fixed procurement lead time parameter, calculates a reference index value, performs the simulation of the inventory quantity transition using a variable procurement lead time parameter and the proper inventory quantity as the primary plan, and calculates the comparative index value. When an inventory reference determination part 43 determines that the comparative index value is equivalent to or better than the reference index value, it determines the proper inventory quantity as the first plan at that time as the final plan of the proper inventory quantity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an appropriate inventory amount determination system and an appropriate inventory amount determination method for determining an appropriate inventory amount that is a reference value for inventory management.

  In inventory management that manages the inventory quantity of the product according to the quantity of goods in and out of the product, the appropriate inventory quantity is determined in a short time so that there is no out-of-stock condition where there is no inventory product and excessive inventory is not held. Is required. As a technique for determining such an appropriate stock amount, there is one described in Patent Document 1, for example.

Specifically, in Patent Document 1, a plurality of parameters used for the inventory amount transition simulation are obtained based on the respective actual values such as the procurement period, the quantity of goods in and out, and the timing, and the out-of-stock occurrence rate is a predetermined threshold value. A technique for determining an appropriate inventory quantity by simulating the inventory quantity transition until substantially equal to
Japanese Patent Laid-Open No. 11-39410

  By the way, Patent Document 1 described above discloses a method in which a product is delivered after a fixed procurement lead time when an inventory amount falls below an order point in an inventory amount transition simulation.

  However, in reality, even when the same product is procured, when there is a change in inventory quantity due to a sudden decrease in inventory, or when there is a change in inventory quantity depending on the order timing such as the beginning of the month or during the month, etc. In some cases, the procurement lead time differs depending on the situation.

  Specifically, in the past, instead of having the manufacturer hold excessive inventory, the supplier had excessive inventory, but in recent years, neither the supplier nor the manufacturer has excessive inventory, and downstream There is a tendency to operate the business in line with the movement of (next process).

  In this situation, considering the case where an order is placed due to a sudden drop in inventory, such as when there is a sudden product sale, both the supplier and the manufacturer are synchronized with the downstream movement of the sales company. However, there is a tendency that production delays and procurement lead time becomes longer. Conversely, let us consider a case where an order is placed at the end of the month that takes a scheduled delivery date. Generally, because some inventory management indicators are evaluated based on the inventory at the end of the month, stock delivery before the scheduled delivery date is more annoying for the delivery destination than it is delayed. Due to the consciousness that it should be difficult, the phenomenon of short procurement lead time tends to occur.

  Thus, the procurement lead time may vary depending on the situation. For this reason, the conventional technique often has a gap between a simulation result obtained by setting the procurement lead time as a fixed value and a real scene.

  Therefore, the present invention has been devised to solve the above-described problems, and greatly increases the gap between the appropriate inventory amount calculated with the procurement lead time as a fixed value and the appropriate inventory amount in the actual situation. An object of the present invention is to provide an appropriate inventory quantity determination system and an appropriate inventory quantity determination method capable of reducing and improving the accuracy of an appropriate inventory quantity for a real scene.

  According to the present invention, the appropriate inventory amount as the first plan is based on the receipt / entry record data including the record of entry / exit of the product and various parameters including the fixed procurement lead time parameter indicating the procurement lead time set to a fixed value. Based on the result of calculating the inventory quantity transition obtained by simulating the inventory quantity transition based on the appropriate inventory quantity as the first proposal obtained by the first proposal calculation unit A reference index value calculation unit that calculates a reference index value that quantifies the quality of the inventory quantity transition, a variable procurement lead time parameter that indicates a variable lead time, and an appropriate inventory quantity as the first plan A comparison index value calculation unit that calculates a comparison index value that quantifies the quality of the inventory volume transition based on the inventory volume transition calculation result obtained by simulating the inventory volume transition using In order to solve the above-described problem, the comparison index value calculated by the comparison index value calculation unit by the appropriate inventory amount calculation unit is worse than the reference index value calculated by the reference index value calculation unit. If it is determined, the appropriate inventory amount as the first proposal is updated, the processing by the reference index value calculation unit and the processing by the comparison index value calculation unit are performed, and the comparison index value is equal to or equal to the reference index value. If it is determined that the value is better than the index value, the appropriate stock amount as the first plan at that time is determined as the proper stock amount of the final plan.

  According to the appropriate inventory quantity determination system and the appropriate inventory quantity determination method according to the present invention, it is possible to obtain an inventory quantity transition simulation result in which the procurement lead time is changed depending on the situation, and the appropriate quantity calculated with the procurement lead time as a fixed value. The gap between the inventory quantity and the appropriate inventory quantity in the actual situation can be greatly reduced, and the accuracy of the appropriate inventory quantity for the actual situation can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The present invention is applied to an appropriate inventory quantity determination system that determines an appropriate inventory quantity that is a reference value for inventory management. This appropriate inventory quantity determination system performs inventory quantity transition simulation using variable procurement lead time for the appropriate inventory quantity calculated with the procurement lead time as a fixed value. By determining the appropriate inventory quantity by evaluating the above, it is intended to improve the accuracy with respect to the actual situation with respect to the appropriate inventory quantity serving as a criterion for judging the order timing and the threshold value.

  First, the functional configuration of the appropriate inventory quantity determination system will be described. As shown in FIG. 1, the appropriate inventory quantity determination system to which the present invention is applied is calculated by an inventory standard parameter calculation unit 10 that calculates various parameters PM1 used for inventory quantity transition simulation, and the inventory standard parameter calculation unit 10. An inventory simulation calculation unit 20 that artificially calculates an inventory amount transition based on various parameters PM1 and a variable procurement lead time parameter VLT described later, a variable procurement lead time parameter calculation unit 30 that calculates a variable procurement lead time parameter VLT, And an appropriate inventory quantity determining unit 40 that determines an appropriate inventory quantity based on the inventory quantity transition calculation result by the inventory simulation calculating section 20. This appropriate stock quantity determination system is constituted by a personal computer, for example, and implements each function by executing a predetermined program by the processor.

  The inventory reference parameter calculation unit 10 changes the inventory amount based on the entry / exit record data SRD including the entry / exit record of the product and the master information MD in which information on the product managed by the predetermined master management unit is described. Various parameters PM1 used for the simulation are calculated. The entry / exit record data SRD is information input according to a user's input operation, and includes, for example, information indicating each record value such as a simulation execution period, a procurement lead time, a quantity of entry / exit, and an entry / exit time. . Here, the procurement lead time is set to a predetermined fixed value. That is, the stock standard parameter calculation unit 10 calculates various parameters PM1 including a fixed procurement lead time parameter set to a fixed value. The inventory reference parameter calculation unit 10 supplies the calculated parameter PM1 to the inventory simulation unit 20.

  When information such as the stock quantity at the start of simulation (current stock quantity), the order cycle, and the most recent order date is input according to the user's input operation, the stock simulation calculating unit 20 Based on the various parameters PM1 calculated by the inventory standard parameter calculation unit 10, the inventory quantity transition is simulated. In other words, the inventory simulation unit 20 performs a simulation of inventory amount transition using the fixed procurement lead time.

  In addition, the inventory simulation calculation unit 20 calculates the inventory amount transition in a pseudo manner based on the entry / exit record data SRD and the variable procurement lead time parameter VLT calculated by the variable procurement lead time parameter calculation unit 30. That is, the inventory simulation unit 20 also performs a simulation of inventory amount transition using the variable procurement lead time.

  The stock simulation calculation unit 20 calculates index values such as the number of missing items (out of stock occurrence rate) and the inventory turnover rate based on the result of calculating the inventory amount transition obtained as a result of the simulation, and uses this index value as the appropriate inventory. It supplies to the quantity determination part 40. This index value is obtained by quantifying the quality of inventory amount transition obtained as a result of simulation. At this time, the inventory pseudo-calculation unit 20 uses the first index value storage unit 41 in the appropriate inventory amount determination unit 40 for the index value based on the inventory amount transition calculation result obtained as a result of the simulation using the fixed procurement lead time. Is stored as a reference index value. In addition, the inventory simulation calculation unit 20 stores the index value based on the inventory amount transition calculation result obtained as a result of the simulation using the variable procurement lead time in the second index value storage unit 42 in the appropriate inventory amount determination unit 40. It is stored as a comparison index value.

  The variable procurement lead time parameter calculation unit 30 sets a variable value instead of a fixed value based on the input / output record data SRD and the order record data ORD including the order record of the product input in response to the user's input operation. The variable procurement lead time parameter VLT indicating the variable procurement lead time is calculated. The variable procurement lead time parameter calculation unit 30 supplies the calculated variable procurement lead time parameter VLT to the inventory simulation unit 20.

  The appropriate inventory quantity determination unit 40 stores a first index value storage unit 41 that stores a reference index value supplied from the inventory simulation calculation unit 20 and a second index value that stores a comparison index value supplied from the inventory simulation calculation unit 20. Based on the index value storage unit 42, the reference index value stored in the first index value storage unit 41, and the comparison index value stored in the second index value storage unit 42. And an inventory standard determination unit 43 that determines an appropriate inventory amount. Such an appropriate inventory amount determination unit 40 calculates various parameters PM <b> 2 based on the appropriate inventory amount determined to be appropriate by the inventory reference determination unit 43. The various parameters PM2 are used as parameters input during the next inventory quantity transition simulation.

  Such an appropriate inventory quantity determination system equipped with each part calculates an appropriate inventory quantity by performing an inventory quantity transition simulation using a fixed procurement lead time, and performs an inventory quantity transition simulation using a variable procurement lead time. The stock quantity is calculated, and the appropriate stock quantity as the final plan is determined by evaluating the validity and risk of the proper stock quantity.

  Such an appropriate inventory quantity determination system determines an appropriate inventory quantity as a final plan, for example, according to a series of procedures as shown in FIG.

  First, as shown in FIG. 2, the appropriate stock quantity determination system stores the input warehousing / acquisition data SRD in a predetermined storage unit in step S1, and in step S2, the stock standard is based on the master information MD. The parameter calculator 10 calculates various parameters PM1. At this time, as described above, the inventory standard parameter calculation unit 10 calculates various parameters PM1 including the fixed procurement lead time parameter set to a fixed value.

  Subsequently, in step S3, the inventory simulation calculation unit 20 obtains an appropriate inventory amount as the first proposal based on the various parameters PM1 calculated by the inventory standard parameter calculation unit 10, and the inventory based on the appropriate inventory amount is obtained. Simulate the amount transition. That is, as described above, the inventory simulation unit 20 performs a simulation of inventory amount transition using the fixed procurement lead time.

  Then, in step S4, the stock pseudo-calculation unit 20 obtains predetermined reference index values such as the number of out-of-stock occurrences (out-of-stock occurrence rate) and the inventory turnover rate based on the inventory quantity transition computation result obtained as a result of simulation. The reference index value is calculated and stored in the first index value storage unit 41.

  Subsequently, in step S5, the appropriate inventory quantity determination system stores the input ordering record data ORD in a predetermined storage unit. In step S6, the appropriate stock quantity determination system is variable based on the loading / unloading record data SRD and ordering record data ORD. The procurement lead time parameter calculation unit 30 calculates the variable procurement lead time parameter VLT. This variable procurement lead time parameter VLT calculation process will be described in detail later.

  Subsequently, in step S7, the inventory pseudo-operation unit 20 changes the inventory amount based on the appropriate inventory amount as the first proposal and the variable procurement lead time parameter VLT calculated by the variable procurement lead time parameter calculation unit 30. Calculate pseudo. That is, as described above, the inventory simulation unit 20 performs a simulation of inventory amount transition using the variable procurement lead time.

  Then, in step S8, the stock pseudo-calculation unit 20 obtains predetermined comparison index values such as the number of out-of-stock occurrences (out-of-stock occurrence rate) and the inventory turnover rate based on the inventory quantity transition computation result obtained as a result of the simulation. The comparison index value is calculated and stored in the second index value storage unit 42.

  In response to this, the stock standard determination unit 43 in the appropriate stock quantity determination unit 40 stores the reference index value stored in the first index value storage unit 41 and the second index value storage unit 42 in step S9. In step S10, it is determined whether or not the comparison index value is equal to or better than the reference index value.

  Here, when the stock standard determination unit 43 determines that the comparison index value is worse than the standard index value, the process proceeds to step S11, and various parameters (appropriate values obtained as the first proposal are obtained). (Stock quantity) is updated, and the processing from step S7 is repeated.

  When the stock standard determination unit 43 determines in step S10 that the comparison index value is equal to or better than the reference index value, in step S12, the inventory plan determination unit 43 The proper stock quantity is determined as the proper stock quantity of the final plan, and a series of processing is finished.

  In order to specifically describe the processing in steps S9 to S11, a case where the stock pseudo-calculation unit 20 calculates the number of missing items and the number of missing items as index values will be described with reference to FIG. As shown in FIG. 3 (a), the stock standard determination unit 43 has the reference index value stored in the first index value storage unit 41 as 300 out-of-stock occurrences and out-of-stock occurrence days = 1 day. Yes, when the comparison index value stored in the second index value storage unit 42 is, as shown in FIG. 3B, the number of missing items = 1571 and the number of missing items = 2 days. Since the comparison index value is worse than the reference index value, the process proceeds to step S11. Then, the inventory standard determination unit 43 raises the appropriate inventory quantity (2400 pieces) required as the first proposal by the minimum ordering rod (200 pieces), and creates a new appropriate inventory quantity (2600 pieces) of the first proposal. ) And the process from step S7 is repeated. The minimum order rod is set by various parameters PM1.

  Subsequently, the stock standard determination unit 43 calculates the second appropriate stock amount (2600 pieces) based on the stock amount transition computation result obtained as a result of the simulation by the stock simulation computation unit 20 to be the second. If the comparison index value stored in the index value storage unit 42 is not different from the number of missing items = 1571 and the number of missing items = 2 days, as shown in FIG. The process proceeds to S11. Then, the inventory standard determination unit 43 raises the appropriate inventory amount (2600 pieces) required as the first proposal again by the minimum order rod (200 pieces), and renews the appropriate inventory quantity (2800) of the first proposal. The process from step S7 is repeated.

  Then, the stock standard determination unit 43 calculates the second stock appropriate stock amount (2800) based on the stock amount transition computation result obtained as a result of the simulation by the stock simulation computation unit 20, and the second As shown in FIG. 3D, when the comparison index value stored in the index value storage unit 42 is 300 out-of-stock occurrences and out-of-stock occurrence days = 1 day, the comparison index value is Since it is equal to the reference index value, the process proceeds to step S12, and the appropriate stock quantity (2800) of the first plan at that time is determined as the proper stock quantity of the final plan.

  According to the appropriate inventory quantity determination system, the appropriate inventory quantity as the final plan can be determined according to such a series of procedures.

  As in the conventional technology, the stock quantity transition simulation results using only the fixed procurement lead time indicate that as long as the same product is procured, as shown in FIG. 4, for example, an order is placed when the stock quantity falls below the appropriate stock quantity. As a result, the product is delivered after a fixed procurement lead time.

  On the other hand, the appropriate inventory quantity determination system uses a variable procurement lead time, so that even if the same product is procured, for example, as shown in FIG. A quantity transition simulation result can be obtained. Therefore, the appropriate inventory quantity determination system greatly reduces the gap between the appropriate inventory quantity calculated with the procurement lead time as a fixed value and the appropriate inventory quantity in the actual situation, and improves the accuracy of the appropriate inventory quantity for the actual situation. Can do.

  Next, the calculation process of the variable procurement lead time parameter VLT in step S5 described above will be described.

  First, the variable procurement lead time parameter calculation unit 30 can calculate the variable procurement lead time parameter VLT based on the shipment rate change rate. In this case, the variable procurement lead time parameter calculation unit 30 collects actual measurement values of the procurement lead time, and calculates the variable procurement lead time parameter VLT based on the actually measured procurement lead time value.

  In order to specifically explain this process, consider a case where, for example, entry / exit record data SRD and order record data ORD as shown in FIG. 6A are input to the variable procurement lead time parameter calculation unit 30.

  In this case, the variable procurement lead time parameter calculation unit 30 associates the order with the warehousing using the order number as a key, extracts the actual value of the procurement lead time, and further supplies the shipping data for the nearest N days of the order date. Based on this, the shipment volume change rate is calculated, and as shown in FIG. 6B, for example, as shown in FIG. 6 (b), the procurement lead time detailed data that associates the shipment volume change rate for each order and the actual value of the procurement lead time at that time To do.

Note that the rate of change in shipment amount is as follows: A shipment amount in a fixed period (N days) is A, shipment amount in the whole period is B, and the whole period is M days.
Rate of change in shipment volume = (A / B) x (M / N)
Can be obtained as

  Then, the variable procurement lead time parameter calculation unit 30 assigns a measured procurement lead time value for each shipment amount change rate, for example, as shown in FIG. Based on this, the variable procurement lead time parameter VLT is calculated. For example, as shown in FIG. 7, the variable procurement lead time parameter calculation unit 30 calculates an average of the procurement lead time values when a plurality of procurement lead time values measured for a certain product are within a predetermined range. The value is calculated as a variable procurement lead time parameter VLT.

  Further, as shown in FIG. 8, when there is an existing procurement lead time value for a certain product, the variable procurement lead time parameter calculation unit 30 sets a value reflecting the actual result to the existing procurement lead time value. It may be calculated as a variable procurement lead time parameter VLT.

  As described above, the variable procurement lead time parameter calculation unit 30 collects data that associates the rate of change in shipment amount immediately before placing an order and the actual value of the procurement lead time at that time, and variable procurement based on this data. The lead time parameter VLT can be calculated. Then, the inventory simulation unit 20 sets the variable procurement lead time parameter VLT calculated in this way according to the shipment amount change rate during the inventory amount transition simulation.

  According to the appropriate inventory quantity determination system, by using the variable procurement lead time parameter VLT calculated in this way, it is possible to perform an inventory quantity transition simulation in consideration of the influence of the procurement lead time due to rapid product sales, The accuracy of the appropriate inventory amount can be improved.

  Further, the variable procurement lead time parameter calculation unit 30 can also calculate the variable procurement lead time parameter VLT based on the ordering time, such as the working day. Also in this case, the variable procurement lead time parameter calculation unit 30 collects the actual value of the procurement lead time, and calculates the variable procurement lead time parameter VLT based on the actually measured procurement lead time value.

  In order to specifically explain this processing, consider a case where procurement lead time detailed data as shown in FIG. In addition, as described above, the procurement lead time detailed data is obtained by associating the order with the receipt using the order number as a key based on the entry / exit record data SRD and the order record data ORD, and obtaining the actual value of the procurement lead time. Further, it is created by calculating a shipment amount change rate based on the shipment data for the most recent N days of the order date.

  In this case, the variable procurement lead time parameter calculation unit 30 assigns an actual procurement lead time value for each ordering time, as shown in FIG. Based on this, the variable procurement lead time parameter VLT is calculated. Note that the variable procurement lead time parameter calculation unit 30, for example, as shown in FIG. 10, divides the month into six periods from the first period to the sixth period and sets each period as one ordering time, and actually measures each period. Assign procurement lead time values. At this time, the variable procurement lead time parameter calculation unit 30 prioritizes the sixth period when the sixth period overlaps with the previous working day.

  As described above, the variable procurement lead time parameter calculation unit 30 collects data that associates the ordering timing with the actual value of the procurement lead time at that time, and calculates the variable procurement lead time parameter VLT based on this data. be able to. Then, the inventory simulation unit 20 sets the variable procurement lead time parameter VLT calculated in this way according to the ordering time at the time of inventory quantity transition simulation.

  According to the appropriate inventory quantity determination system, by using the variable procurement lead time parameter VLT calculated in this way, it is possible to perform an inventory quantity transition simulation in consideration of the influence of the procurement lead time due to the early inventory shipment of the supplier. And the accuracy of the appropriate inventory can be improved.

  Furthermore, the variable procurement lead time parameter calculation unit 30 can calculate the variable procurement lead time parameter VLT as follows when there is no ordering record or entry / exit record.

  That is, the variable procurement lead time parameter calculation unit 30 can set the variable procurement lead time parameter VLT as variables such as a reference value, an upper limit value, a lower limit value, and a step value as shown in FIG. In addition, a procurement lead time setting table storing these variables is stored in a memory or the like. Then, the variable procurement lead time parameter calculation unit 30 sets, as a procurement lead time value, a value obtained by adding or subtracting each step value within a predetermined range of, for example, 80% to 120% centered on the reference value, as shown in FIG. As shown in FIG. 5, the procurement lead time value is assigned for each shipment amount change rate or ordering time, and based on this, the variable procurement lead time parameter VLT is calculated.

  As described above, according to the appropriate inventory quantity determination system, the variable procurement lead time parameter VLT can be set as a variable so that the variable procurement lead time parameter VLT based on the actual value is not maintained. Therefore, it is possible to set an appropriate inventory amount after taking in the assumed risk.

  As described above in detail, according to the appropriate inventory quantity determination system according to the embodiment of the present invention, the inventory pseudo-calculation unit 20 calculates the first order obtained based on the various parameters PM1 including the fixed procurement lead time parameter. Simulation of inventory quantity transition based on the appropriate inventory quantity as a plan, calculate a predetermined reference index value based on the result of inventory quantity transition calculation, variable procurement lead time parameter and appropriate inventory quantity as the first proposal Are used to perform a simulation of inventory quantity transition, and a predetermined comparison index value is calculated based on the inventory quantity transition calculation result. Then, the appropriate inventory quantity determination system according to the present invention provides a first order when the inventory standard determination unit 43 in the appropriate inventory quantity determination unit 40 determines that the comparison index value is worse than the reference index value. Update the appropriate inventory amount as a plan and repeat the index value calculation process, and if it is determined that the comparison index value is equal to or better than the reference index value, The appropriate stock amount as one plan is determined as the proper stock amount of the final plan.

  Therefore, according to this appropriate inventory quantity determination system, it is possible to obtain the inventory quantity transition simulation result with the procurement lead time changed according to the situation, the appropriate inventory quantity calculated with the procurement lead time as a fixed value and the appropriateness in the actual situation. The gap with the inventory quantity can be greatly reduced, and the accuracy of the appropriate inventory quantity for the actual situation can be improved.

  In this appropriate inventory quantity determination system, the variable procurement lead time parameter calculation unit 30 collects data associating the change rate of the shipment quantity immediately before placing an order and the actual value of the procurement lead time at that time, Based on the data, the variable procurement lead time parameter VLT is calculated, and this variable procurement lead time parameter VLT is set according to the rate of change in the shipment amount at the time of simulation by the inventory simulation unit 20.

  Thereby, according to this appropriate inventory quantity determination system, it is possible to perform an inventory quantity transition simulation that takes into account the influence of procurement lead time due to rapid product sales, etc., and to improve the accuracy of the appropriate inventory quantity.

  Furthermore, in this appropriate inventory quantity determination system, the variable procurement lead time parameter calculation unit 30 collects data relating the ordering timing and the actual value of the procurement lead time at that time, and based on this data, the variable procurement lead time is calculated. The time parameter VLT is calculated, and the variable procurement lead time parameter VLT is set according to the ordering time at the time of the simulation by the inventory simulation calculation unit 20.

  As a result, according to the appropriate inventory quantity determination system, it is possible to perform an inventory quantity transition simulation that takes into account the influence of procurement lead time due to the early inventory shipment of the supplier, etc., and to improve the accuracy of the appropriate inventory quantity. .

  Furthermore, according to the appropriate inventory quantity determination system, the variable procurement lead time parameter calculation unit 30 can calculate from the procurement lead time reference value, upper limit value, lower limit value, and step value read from the predetermined procurement lead time setting table. By calculating the variable procurement lead time parameter VLT based on the following variables, even if the variable procurement lead time parameter VLT based on actual values is not in place, the appropriate inventory after taking in the assumed risk The amount can be set.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

It is a block diagram which shows the functional structure of the appropriate stock quantity determination system to which this invention is applied. It is a flowchart which shows a series of processes at the time of determining the appropriate inventory quantity as a final plan in the appropriate inventory quantity determination system to which this invention is applied. In the appropriate inventory quantity determination system to which the present invention is applied, how to determine the appropriate inventory quantity as the final plan when the inventory simulation unit calculates the number of missing items and the number of missing items as index values will be described. FIG. It is a figure which shows the specific example of the result by the stock amount transition simulation which used only fixed procurement lead time in the prior art. It is a figure which shows the specific example of the result by the stock quantity transition simulation using the variable procurement lead time in the appropriate stock quantity determination system to which this invention is applied. It is a figure for demonstrating a mode that a variable procurement lead time parameter is calculated based on a shipment amount change rate in the appropriate inventory quantity determination system to which this invention is applied. It is a figure for demonstrating a mode that the average value of the several procurement lead time value measured actually is calculated as a variable procurement lead time parameter in the appropriate stock quantity determination system to which this invention is applied. It is a figure for demonstrating a mode that the value which reflected the result on the existing procurement lead time value is calculated as a variable procurement lead time parameter in the appropriate inventory quantity determination system to which this invention is applied. It is a figure for demonstrating a mode that a variable procurement lead time parameter is calculated based on an ordering time in the appropriate stock quantity determination system to which this invention is applied. In the appropriate inventory quantity determination system to which the present invention is applied, the month is divided into six periods from the first period to the sixth period, each period is set as one ordering time, and the procurement lead time value measured for each period is assigned. It is a figure for demonstrating. It is a figure for demonstrating a mode that the said variable procurement lead time parameter is calculated when the variable procurement lead time parameter can be set as a variable in the appropriate inventory quantity determination system to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inventory reference | standard parameter calculation part 11 Unexamined-Japanese-Patent No. 20 Inventory simulation calculation part 30 Variable procurement lead time parameter calculation part 40 Proper inventory quantity determination part 41 1st index value storage part 42 2nd index value storage part 43 Inventory reference | standard determination part

Claims (5)

The first to determine the appropriate inventory amount as the first plan based on the receipt / entry record data including the record of entry / exit of the product and various parameters including the fixed procurement lead time parameter indicating the fixed lead time. The next plan calculation part,
Based on the inventory quantity transition calculation result obtained by simulating the inventory quantity transition based on the appropriate inventory quantity as the first proposal obtained by the first proposal calculation unit, the quality of the inventory quantity transition is determined. A reference index value calculation unit for calculating a quantified reference index value;
Based on the inventory quantity transition calculation result obtained by simulating the inventory quantity transition using the variable procurement lead time parameter indicating the procurement lead time made variable and the appropriate inventory quantity as the first proposal, A comparison index value calculation unit that calculates a comparison index value that quantifies the quality of the inventory volume transition;
When it is determined that the comparison index value calculated by the comparison index value calculation unit is worse than the reference index value calculated by the reference index value calculation unit, the appropriate inventory as the first proposal The amount is updated so that the process by the reference index value calculation unit and the process by the comparison index value calculation unit are performed, and it is determined that the comparison index value is equal to or better than the reference index value In this case, an appropriate inventory quantity determination system comprising: an appropriate inventory quantity calculation unit that determines the appropriate inventory quantity as the first proposal at that time as the appropriate inventory quantity of the final proposal. A variable procurement lead time parameter calculating unit for calculating the variable procurement lead time parameter;
The variable procurement lead time parameter calculation unit collects data associating a rate of change in shipment amount immediately before placing an order and an actual value of procurement lead time at that time, and based on this data, the variable procurement lead time parameter The appropriate inventory quantity determination system according to claim 1, wherein the variable procurement lead time parameter is set according to a shipment quantity change rate during the simulation. A variable procurement lead time parameter calculating unit for calculating the variable procurement lead time parameter;
The variable procurement lead time parameter calculation unit collects data associating an ordering timing and an actual value of the procurement lead time at that time, calculates the variable procurement lead time parameter based on the data, and calculates the variable procurement The system according to claim 1, wherein a lead time parameter is set in accordance with an ordering time at the time of the simulation.   The variable procurement lead time parameter calculation unit calculates the variable procurement lead time parameter based on a variable including a reference value, an upper limit value, a lower limit value, and a step value of the procurement lead time read from a predetermined setting table. The system for determining an appropriate amount of inventory according to claim 2, wherein the system is appropriate. The first to determine the appropriate inventory amount as the first plan based on the receipt / entry record data including the record of entry / exit of the product and various parameters including the fixed procurement lead time parameter indicating the fixed lead time. And the process of
Based on the result of calculating the inventory quantity transition obtained by simulating the inventory quantity transition based on the appropriate inventory quantity as the first proposal obtained in the first step, the quality of the inventory quantity transition is numerically determined. A second step of calculating the normalized reference index value;
Based on the inventory quantity transition calculation result obtained by simulating the inventory quantity transition using the variable procurement lead time parameter indicating the procurement lead time made variable and the appropriate inventory quantity as the first proposal, A third step of calculating a comparative index value that quantifies the quality of the inventory volume transition,
When it is determined that the comparison index value calculated in the third step is worse than the reference index value calculated in the second step, the comparison index value is obtained in the first step. Update the appropriate inventory amount as the first proposal, repeat the second step and the third step,
When it is determined that the comparison index value is equal to or better than the reference index value, the appropriate inventory quantity as the first proposal at that time is determined as the appropriate inventory quantity of the final proposal A method for determining the appropriate inventory quantity, characterized by

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