JP2006342002A - Inventory planning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems in a conventional inventory control/planning method wherein problems occur in inventory and delivery according to a variation in demand and accordingly large inventory must be secured for safety. <P>SOLUTION: In an inventory planning server 100, the demand characteristic and the supply characteristic of commodities and a lead time and a planning cycle in a commodity distribution route are received from a production control server 200, a transport control server 300, and a sales control server 400, and a necessary inventory quantity is calculated by using these data. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a technology for executing inventory management of merchandise. In particular, it relates to the creation of an inventory plan for more efficient production and transportation.

  Conventionally, there is JP-A-8-235274 as a prior art for executing inventory management of merchandise. This prior art uses both the “MRP method” and the “JIT method”. More specifically, JIT items can be handled even though it is an MRP method, the inventory forecast of JIT items can be performed, and the validity of the “kanban number” and “order quantity” can be verified. An inventory management system is disclosed in which an update cycle is shortened by shortening an update time (“number of kanbans” and “order quantity”), and a procurement activity that follows a change in the market is performed.

JP-A-8-235274

  However, in the above-described conventional technology, there is a problem that a problem occurs in inventory and delivery according to a change in demand. Also, due to this problem, a large amount of inventory had to be kept as a safety stock.

  This is because the prior art is simply a collection of “MRP method” and “JIT method”. First, in the “MRP method”, the production quantity is leveled, and the inventory quantity is adjusted according to the fluctuating demand quantity. For this reason, in the “MRP method”, highly accurate demand prediction is performed to reduce the inventory. However, if the accuracy of demand forecasting is not high, excess or shortage of inventory will become apparent.

  In the “JIT method”, the inventory quantity is leveled, and the production quantity is adjusted according to the changing demand quantity. In addition, since the “JIT method” does not have a safety stock corresponding to demand fluctuation, if the accuracy of the kanban size is poor, a shortage or delivery delay occurs.

  The above-mentioned conventional techniques cannot be solved simultaneously with the shortage of inventory and the shortage / delivery delay due to the mere combination of “MRP method” and “JIT method”.

  An object of the present invention is to solve the above-described problems, reduce shortage and delivery delay, and stabilize the inventory at a certain level.

  In order to solve the above-described problems, in the present invention, the necessary inventory amount is calculated in consideration of the lead time and the planning cycle in the distribution channel of the commodity in the demand characteristic and supply characteristic of the commodity.

  Note that the lead time indicates a delivery period of a product from a product supplier to a demand destination including a store. The planning cycle indicates a period of inventory planning performed periodically.

  Further, the demand characteristics of the product include a moving average demand amount and a standard deviation that are average values of demand amounts in a predetermined period. Further, the supply characteristic includes a safety stock coefficient.

  Further, the present invention includes calculating the replenishment request amount from the necessary inventory amount. In this case, in addition to calculating the necessary stock amount and the replenishment request amount at the time of calculation, it includes calculating the future necessary stock amount and the replenishment request amount. Furthermore, the present invention includes calculating a necessary inventory amount and a replenishment request amount in consideration of a lead time that is a distribution period to a store.

  According to the present invention, even if the demand fluctuates, the production amount and the stock amount can be further stabilized.

  First, the application destination in the embodiment of the present invention will be described. In the present embodiment, the present invention is applied to an inventory plan on a distribution channel in which a product produced by a production company is transported to a store by the transportation means of the transportation company and sold. That is, the effective inventory amount in each of the production company, the shipping company, and the sales store is calculated. In this case, there may be a plurality of production companies, shipping companies, and sales stores that handle the target product.

  Further, the production company uses a production management server 200 described later to manage the production and grasp the production status. In addition, the shipping company uses the shipping management server 300 described later to manage shipping and grasp the shipping status. Further, the store uses a sales management server 400 (to be described later) to manage sales and grasp the sales status.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system configuration diagram showing the configuration of the inventory planning system of the present embodiment. The inventory planning system includes an inventory planning server 100, a production management server 200, a transportation management server 300, and a sales management server 400 that are connected via a network 500. There may be a plurality of these servers. In particular, the production management server 200, the transportation management server 300, and the sales management server 400 are numbers according to the form of the distribution route.

  Further, the inventory planning server 100 may be integrated with any one of the production management server 200, the transportation management server 300, and the sales management server 400. Furthermore, each of the inventory planning server 100, the production management server 200, the transportation management server 300, and the sales management server 400 may be a computer having a general structure, and performs processing according to a program that can be stored in a storage device. Execute.

  Each truck terminal 350 can be used by a transportation means such as a truck or a ship, and may be connected to the network 500 or to another network to which the transportation management server 300 is connected. The truck terminal 350 may also be a computer having a general structure, and a processing device including a processor executes processing according to a program that can be stored in a storage device.

  Next, the processing flow of the present embodiment will be described with reference to the flowcharts shown in FIG. 2, FIG. 11, FIG. 12, and FIG.

  First, in step 1000, the inventory planning server 100 receives inputs of a product ID 90 for identifying a product 1 to be planned, a planning cycle C10, a lead time L20, a service rate s30, and a moving average period tm40. These pieces of input information are input from an inventory manager who is a user of the inventory planning server.

These pieces of information may be in accordance with the contents of a product sales strategy established by an inventory manager or the like. The planning cycle C10 is a value according to the product sales plan for “how much time cycle to supply”. In addition, the lead time L20 indicates a time during which the product is distributed from the production base to the sales base. Further, the service rate s30 is a value according to the product sales plan that indicates how much the product is not to be out of stock.

  As will be described later, the information input in step 1000 may be configured to input a value when actually used in addition to manual input.

  Next, in step 1001, the inventory planning server 100 requests the sales management server 400 for the actual demand amount of the product 1 in a predetermined period. For example, the inventory planning server 100 sends request information including the product ID 90 and the moving average period tm40 to the sales management server 400.

  Next, in step 1002, the sales management server 400 calculates a demand amount record corresponding to the sent request information. Using the sent product ID 90 as a search key, the sales amount for the moving average period tm40 is searched from the sales result DB 410 shown in FIG. 3, and this is calculated as the demand amount result.

  Next, in step 1003, the sales management server 400 transmits the calculated demand volume result to the inventory planning server 100.

Next, the inventory management server 100 calculates a moving average demand amount Qd15 of the demand amount from the demand amount result received in step 1004. This is an average value of the actual demand amount for each predetermined partial moving average period constituting the moving average period tm40. For example, the moving average period tm40 is one year and the partial moving average period is one week. In this case, the moving average demand amount Qd15 is calculated by dividing the total of the demand amount results for one year by 52 (weeks) constituting one year. The moving average demand amount Qd15 may be calculated using the following (Equation 1).
(Qd = Σ (Qd (i)) / tm) (Equation 1)
In addition, the inventory planning server 100 stores the calculated moving average demand amount Qd15 at a location corresponding to the product ID 90 in the column 122 of the inventory planning table 120 shown in FIG.

  Note that the sales management server 400 calculates the latest partial moving average period sales amount to the inventory planning server 100 in step 1002 and sends the calculated sales amount to the inventory management server 100 in step 1003. Good. In this case, the inventory planning server 100 uses the sales amount DB (past portion) 110 shown in FIG. 5 and the sales amount sent in the moving amount managed in the partial moving average period transmitted before that as the moving average. The demand amount Qd15 is calculated.

  Note that step 1006 may be executed by the sales management server 400. That is, the sales management server 400 calculates the moving average demand amount Qd15 and sends it to the inventory planning server 100.

  Next, in step 1007, the inventory planning server 100 determines whether trend correction is necessary. If trend correction is necessary, correction is executed in step 1008 and the process proceeds to step 1009. The trend correction is to correct the moving average demand amount Qd15 according to the increase / decrease trend of the demand. In step 1007, when the increase / decrease tendency exceeds a predetermined value, it is determined that trend correction is necessary. Details of the trend correction will be described later.

  Next, in step 1009, a standard deviation σd60 of the moving average demand amount Qd15 is calculated. The standard deviation σd60 may be calculated using the following (Equation 2).

In addition, the inventory planning server 100 stores the calculated moving average demand amount Qd15 at a location corresponding to the product ID 90 in the column 123 of the inventory planning table 120 shown in FIG.
(I = Qd (L + C) + k√ (L + C) σd) → (σd = √ (Σ (Qd−Qd (i)) ² / (tm−1))) (Equation 2)
Next, in Step 1010, the inventory planning server 100 calculates the safety stock coefficient k70 from the service rate s30 using the safety coefficient calculation table 150 shown in FIG. That is, the safety stock coefficient k70 corresponding to the service rate s30 input in step 1000 is selected in the safety coefficient calculation table 150.

  Next, in Step 1011, the inventory planning server 100 determines whether or not the safety stock coefficient k70 calculated in Step 1010 needs to be corrected. When correction is necessary, correction is performed using the safety stock coefficient correction table 160.

  Here, in step 1011, whether or not correction is necessary is determined according to the distribution of the moving average demand amount Qd15. That is, when at least one of the kurtosis and σd / Qd of this distribution exceeds a predetermined threshold value, it is determined that correction is necessary. The reason for this is that the required inventory is based on the assumption that normal demand is normally distributed. However, the actual demand distribution is not a normal distribution, and the base is wider than the normal distribution, or the kurtosis is higher than the normal distribution. In these cases, the service rate will not correspond to the actual demand.

  Therefore, in step 1012, using the safety stock coefficient correction table 160 corresponding to the expected service rate s30, for a demand whose kurtosis is higher than the threshold, the larger the kurtosis becomes, the larger the safety stock coefficient becomes σd ( For demands where / Qd) is greater than the threshold, the safety stock coefficient is corrected to be smaller as the demand increases.

Next, in step 1013, the inventory planning server 100 calculates the necessary inventory quantity I using the sum of the planning cycle C10 and the lead time L20, the moving average demand quantity Qd15, the safety inventory coefficient k70, and the standard deviation σd. To do. More specifically, the required inventory quantity I is calculated using the following (Equation 3).
(I = Qd (L + C) + k√ (L + C) σd) (Equation 3)
Next, the inventory planning server 100 calculates an effective inventory quantity in order to calculate the replenishment request quantity. The processing in step 1014, which is an example of calculating the effective inventory amount, will be described below. The effective inventory amount is the sum of the actual inventory amount and the remaining order. Therefore, the quantity that has not been ordered (delivered) among the ordered quantities may be used as the effective inventory quantity. Further, the effective inventory quantity may be calculated by subtracting the quantity ordered (delivered) from the order quantity.

  First, in step 1014, the inventory planning server 100 requests the production management server 200 and the sales management server for an inventory record indicating the amount of inventory to be managed. The inventory planning server 100 transmits inventory result request information including the product ID 90 to the production management server 200 and the sales management server 400.

  Next, in step 1015, the production management server 200 searches the production plan / management DB 210 shown in FIG. 9 for the actual inventory of the production company corresponding to the product ID 90. For example, the quantity indicated by the item corresponding to the product ID 90 in the order quantity (order quantity) 214 is output as a search result. The search result may be the sum of 214-a to e instead of the order quantity 214. Note that the order quantity 214 indicates the order quantity of production instructed to the production company (or the production company itself), and the items 214-a to e indicate the breakdown of the order quantity 214.

  In step 1017, the sales management server 400 searches the stock management DB 420 shown in FIG. 4 for the stock record of the store (company) corresponding to the product ID 90 transmitted from the stock planning server 100 in step 1014. For example, the on-hand inventory amount 426 of the product ID 423 corresponding to the transmitted product ID 90 is output as a search result.

  Next, in step 1019, the inventory planning server 100 receives the inventory record transmitted from the production management server 200 in step 1016 and the inventory record transmitted from the sales management server 400 in step 1018. Note that step 1019 may not be one step, but may be two steps corresponding to the number of transmission sources.

  In Step 1020, the inventory planning server 100 requests the production management server 200 for shipping data including a shipping ID corresponding to the product ID. For example, the inventory planning server 100 transmits shipping data request information including the product ID 90 to the production management server 200.

  Next, in step 1021, the production management server 200 searches the production plan / result DB 210 for a shipment ID corresponding to the product ID 90 and its delivery amount. That is, the product ID corresponding to the transmitted product ID 90 is searched from the item 211, and the shipment ID associated with the searched product ID (in the same column) is searched from the item 214-e1.

  Next, in step 1022, the production management server 200 transmits information including the searched shipping ID and the amount to be sent and the corresponding product ID to the inventory planning server 100.

  Next, in step 1023, the inventory planning server 100 requests transportation information that is information relating to the product being transported corresponding to the shipping ID transmitted from the production management server 200. For example, the inventory planning server 100 transmits transportation information request information including a shipping ID to the transportation management server 300.

  Next, in step 1024, the transportation management server 300 searches for transportation information corresponding to the shipping ID and including the shipping ID and the transportation amount (received amount). For example, the transportation management server 300 uses the tracking processing program 320 to collect the consignment ID being transported from the truck terminal 350 installed in each transportation means, and from the stock planning server 100 among the collected consignment IDs. The transportation information related to the transmitted shipping ID is retrieved from the transportation management DB 310 shown in FIG. The transportation means is capable of transporting goods including trucks, ships, and airplanes. The transportation management server 300 may collect information to be registered in the transportation management DB 310 from each truck terminal 350 at a predetermined timing, and search the transportation management DB 350 when there is a request for transportation information. .

  Next, in step 1025, the transportation management server 300 transmits transportation information to the inventory planning server 100.

  Next, in step 1026, the inventory planning server 100 calculates a shipping amount corresponding to the product ID using the shipping DB 130 shown in FIG. 6 from the transmitted transportation information. That is, the inventory planning server 100 identifies a shipment ID included in the transmitted transportation information that corresponds to the product ID 90 and searches the item 131 for the amount of shipment (ordering).

  Next, in step 1027, the inventory planning server 100 calculates the effective inventory quantity by adding the inventory record received in step 1019 and the shipping quantity calculated in step 1026.

  The effective inventory quantity may be calculated as follows. As a first alternative, the inventory planning server 100 requests an effective inventory amount from the sales management server 400. For example, the inventory planning server 100 transmits valid inventory quantity request information including the product ID 90 to the sales management server 400. Next, the sales management server 400 calculates the order quantity corresponding to the product ID 90 from the inventory management DB 420. That is, the sales management server 400 searches the item 425 as to whether or not the product corresponding to the product ID 90 has arrived. If it has arrived, the on-hand inventory quantity 426 is set as the effective inventory quantity. If the item has not arrived, the order quantity 424 is set as the effective stock quantity. In addition, when there are a plurality of items corresponding to the product ID 90 in the inventory management DB 420, they are added to obtain an effective inventory amount. Then, the inventory planning server 100 receives this effective inventory amount from the sales management server 400.

  The second alternative is as follows. The inventory planning server 100 receives from the production management server 200 the production planned medium quantity 214-a to the production completion quantity 214-d corresponding to the product ID 90. The production management server 200 searches the production plan / result DB 210 for these pieces of information. Further, the inventory planning server 100 receives from the transportation management server 300 the shipping / transportation amount 129-e that is the transportation amount corresponding to the product ID 90. This transportation amount may be calculated in the same manner as steps 1020 to 1026.

  Further, the inventory planning server 100 receives the store arrival amount 426-a and the sellable amount 426-b (or the on-hand inventory amount 426) corresponding to the product ID 90 from the sales management server 400. The sales management server 400 searches the stock management DB 420 for a store arrival amount 426-a and a sellable amount 426-b (or hand-held stock amount 426) corresponding to the product ID 90. Then, the inventory planning server 100 adds the received production plan medium amount 426-a and the sellable amount 426-b to make it an effective inventory amount.

  As a third alternative, there are the following. The inventory planning server 100 receives actual physical inventory quantities from the production management server 200, the transportation management server 300, and the sales management server 400, respectively. In addition, the inventory planning server 100 receives an order backlog corresponding to the product ID 90 from at least one of the production management server 200, the transportation management server 300, and the sales management server 400. Then, the effective inventory quantity is calculated by adding the actual inventory quantity and the remaining order. The inventory planning server 100 may be configured to receive order status information indicating an actual inventory quantity and an order status including an order remaining from the production management server 200, the transport management server 300, and the sales management server 400 at each predetermined timing. Good. In this case, the effective stock quantity is calculated from this order status information.

  Next, in Step 1028, the inventory planning server 100 calculates the replenishment request amount by subtracting the effective inventory amount calculated in Step 1027 from the necessary inventory amount I80 calculated in Step 1013.

  Furthermore, the inventory planning server 100 determines whether or not the calculated replenishment request amount needs to be corrected as necessary, and corrects the correction if necessary. These processes are performed in steps 1029 and 1030, details of which will be described later.

  Next, in Step 1031, the inventory planning server 100 executes replenishment of the replenishment request amount to the production management server 200. For example, replenishment request information including the product ID 90 and the replenishment request amount is transmitted to the production management server 200. In step 1031, the replenishment request amount is recorded in the corresponding part of the corresponding product ID among the items 127 of the inventory plan table 120.

  In step 1032, the production management server 200 executes production management based on the replenishment request information.

  Finally, the process returns to step 1000 to perform the process again. In this re-processing, each DB is updated based on the processing so far, and therefore the same processing is executed based on the contents of the updated DB.

  Note that there is a time difference between the time when the replenishment request amount is calculated and the time when the product actually reaches the store. That is, in steps 1005 to 1008, the inventory planning server 100 calculates the moving average demand amount Qd based on the current inventory status. In order to fill this time difference, each moving average demand amount up to after the lead time C20 may be calculated, and the necessary demand amount may be calculated based on this. As these moving average demands, there are the following calculation methods. (1) based on human prediction, (2) using the moving average demand Qd calculated in steps 1005 to 1008, and (3) using the computer such as the inventory planning server 100 to perform prediction. In any method, the input of the moving average demand amount at each timing is accepted, and the input value of each item of the inventory plan table 120 at each timing is calculated based on the inputted moving average demand amount, and the necessary inventory is based on this. The amount is calculated sequentially at each timing. This is because each item at the next timing changes according to the necessary inventory amount (replenishment request amount).

  Next, the trend correction in steps 1007 to 1008 will be described. First, in step 1007, it is determined that trend correction is necessary when the degree of change in demand that occurs with time exceeds a reference. About the change throat, it asks as follows.

  First, the actual demand Qd (i) at each time point is obtained from the item 127 of the inventory plan table 120. Next, for each time point, a demand record Qd (i) before the predetermined period from each time point is similarly obtained. Next, these differences are calculated, and this difference is compared with a predetermined value. If the number of cases where the difference as a result of comparison exceeds a predetermined value is greater than the predetermined number, it is determined that trend correction is necessary. Note that a plan cycle C10 is included before the predetermined period. Further, the predetermined value and the predetermined number may be input from a user of the inventory planning server 100.

  Next, in step 1008, trend correction is executed. First, using the actual demand recorded in the item 127 of the inventory plan table 120, an approximate expression of demand fluctuation in a preset period is obtained. Using this approximate expression, the moving average demand amount Qd is corrected to the moving average demand amount at the time point ahead of the lead time C20. Thus, the trend correction is completed.

  Next, the replenishment request amount correction in steps 1029 to 1030 will be described. First, the processing for determining whether or not the replenishment request amount needs to be corrected in step 1029 will be described.

  First, (1) it is determined whether the lead time L20 input in step 1000 is larger than a predetermined lead time threshold. (2) It is determined whether the standard deviation σd60 calculated in step 1009 is smaller than a predetermined standard deviation threshold. (3) It is determined whether the necessary inventory amount calculated in step 1013 is larger than the effective inventory amount calculated in step 1027. Further, (4) it is determined whether the value obtained by subtracting the effective inventory amount calculated in step 1027 from the necessary inventory amount calculated in step 1013 is larger than the moving average demand amount Qd15. When the conditions (1) to (4) are satisfied, it is determined that the replenishment request amount needs to be corrected.

  Next, in step 1030, if correction is necessary, the replenishment correction amount calculated in step 1028 is corrected to the moving average demand amount Qd15. Note that steps 1029 to 1030 may be performed before step 1028. In this case, if it is determined in step 1029 that correction is necessary, the replenishment correction amount calculated in step 1030 may be used, and the process in step 1028 may be omitted.

It is a system configuration figure of one embodiment in the present invention. It is a flowchart (the 1) which shows the flow of the process in one embodiment in this invention. It is a figure which shows an example of store performance DB410. It is a figure which shows an example of stock management DB420. It is a figure which shows an example of sales performance DB (past part) 110. It is a figure which shows an example of dispatch DB130. It is a figure which shows an example of the stock plan table. It is a figure which shows an example of the service rate of 95% among the safety stock coefficient calculation tables. It is a figure which shows an example of production plan / result DB210. It is a figure which shows an example of transportation management DB310. It is a flowchart (the 2) which shows the flow of the process in one embodiment in this invention. It is a flowchart (the 3) which shows the flow of the process in one embodiment in this invention. It is a flowchart (the 4) which shows the flow of the process in one embodiment in this invention.

Explanation of symbols

Planning cycle ... 10, moving average demand ... 15, lead time L ... 20, service rate s ... 30, moving average period tm ... 40, standard deviation σd ... 60, safety stock coefficient k ... 70, necessary stock I ... 80 , Product ID ... 90, inventory planning server ... 100, production management server ... 200, transportation management server 300, sales management server 400, network ... 500

Claims (1)

In a stock replenishment information transmission method for creating an inventory plan for products distributed through a distribution channel using a computer connected via a network to a sales management server that manages product sales,
The computer accepting an input of a planning cycle of the product and a lead time of the product;
A step of calculating a moving average demand amount indicating an average value for each predetermined period constituting the moving average period of a demand amount record indicating a demand amount of the commodity in a preset moving average period of the commodity;
The calculator calculating a standard deviation in the moving average demand,
Using a service rate indicating a probability that the product is not missing, calculating a safety stock coefficient indicating a probability that the product is not missing,
Depending on the relationship between the ratio of the moving average demand to the standard deviation data and a predetermined threshold, or the relationship between the kurtosis of the distribution of moving average demand and the predetermined threshold, the storage device of the computer A step of correcting the safety stock coefficient using a stored safety stock coefficient correction table, wherein when the kurtosis is higher than a predetermined threshold, the larger the kurtosis is, the larger the safety stock coefficient is; A step of correcting to a smaller safety stock coefficient as it becomes larger if it is larger than the threshold,
Calculating a necessary stock amount of the commodity required in the distribution route using the sum of the planning cycle and the lead time, the moving average demand amount, and the standard deviation and the safety stock coefficient;
The computer calculating an effective inventory amount in the distribution channel;
Calculating a replenishment request amount by subtracting the effective stock amount from the required stock amount, and transmitting a replenishment request including the replenishment request amount and product identification information for identifying the product to the production management server. An inventory replenishment information transmission method characterized by comprising:

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