JP7110793B2 - Appropriate inventory determination support device, method and program - Google Patents

Description

TECHNICAL FIELD The present invention relates to an appropriate inventory determination support device, method, and program for assisting determination of appropriate inventory to be held at a destination to which a plurality of objects are transported.

Steel makers, chemical makers, oil makers, electric power companies, etc. transport objects such as raw materials, materials, products, and commodities from overseas to destinations such as factories, commercial facilities, and inventory bases (for example, delivery destinations) by ship. Imported and stored as inventory at the destination. Excess inventory slows down cash flow and increases management costs. On the other hand, if the inventory is too low, quality deterioration and shortages may occur, which may lead to production reduction or suspension.

In order to avoid overstocking and understocking, it is desirable to evaluate variations in demand and supply of objects and set an average inventory (called appropriate inventory) as a management target. The concept of appropriate inventory will be described with reference to FIG. FIG. 10 is a diagram for explaining the concept of appropriate inventory, in which the horizontal axis indicates time and the vertical axis indicates the amount of inventory, representing changes in inventory. Appropriate inventory is the sum of cycle inventory, which is a running inventory that holds only the steady fluctuations in inventory, and safety inventory, which prevents shortages even when supply and demand fluctuates (Non-Patent Document 1). checking). By determining this appropriate inventory, it is possible to prevent deterioration in quality and occurrence of shortages while preventing a slowdown in cash flow and an increase in management costs.

As a technology of this kind, for example, Patent Document 1 discloses a safety stock rate calculated based on the predicted amount of demand and the actual amount in the past, and the safety stock is calculated by multiplying the predicted amount of future demand by the safety stock rate. In the safety stock calculation method, it is determined whether or not the calculated safety stock ratio exceeds a predetermined upper limit, and if the upper limit is exceeded, the calculated safety stock ratio is replaced by the upper limit. Techniques for calculating safety stock are disclosed.
In addition, in Patent Document 2, for the purpose of appropriately calculating the safety stock of high-mix low-volume products, a plurality of types of parts are grouped by a predetermined method, and a standard deviation model is created with each part group as a population. A method of calculating the safety stock of each part from the standard deviation model of each part group and the preset safety coefficient of each part is disclosed.
In both Patent Documents 1 and 2, by using the appropriate inventory calculation method of Non-Patent Document 1, the appropriate inventory can be calculated by adding the cycle inventory to the safety inventory.

JP-A-2000-207479 JP 2008-293319 A

Written by Takao Suguro, "Appropriate Inventory Concepts and Methods", published on September 10, 2003, Nikkan Kogyo Shimbun

However, Patent Literature 1 does not show a rational setting method for the upper and lower limits of the safety stock ratio, and the upper and lower limits of the appropriate inventory obtained from the safety stock calculation results depend on the intuition of practitioners. In addition, although Patent Document 2 discloses a method of setting safety stock by grouping, it cannot guarantee that the appropriate stock calculated from the safety stock does not exceed the capacity of the facility or storage space.
In inventory management, if the inventory exceeds the storage capacity of the delivery destination, the incoming objects cannot be stored, causing the vessel to be detained at sea and an additional fee to be paid as a penalty.
Therefore, it is necessary to rationally determine the appropriate inventory based on the storage capacity of the delivery destination. If the appropriate inventory exceeds the storage capacity of the delivery destination, it is required to reduce the number of objects to be managed or consolidate alternative objects.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to rationally determine an appropriate inventory based on the storage capacity of the delivery destination.

The gist of the present invention for solving the above problems is as follows.
[1] An appropriate inventory determination support device for assisting determination of an appropriate inventory to be held at a destination to which a plurality of objects are transported,
an input means for inputting transportation record information for each object and an upper limit value of storage capacity of the transportation destination;
Using the safety inventory held so as not to cause shortages even if demand and supply fluctuates, and the transportation performance information , the inventory management mesh grouping the objects for each transportation destination is used as a calculation unit, and the transportation destination an appropriate inventory calculation means for calculating an appropriate inventory for each
Appropriate upper limit inventory value calculation means for calculating an appropriate upper limit value of inventory based on the maximum amount of incoming goods per predetermined period calculated using the transportation performance information and the upper limit value of storage capacity;
Appropriate inventory determination for determining an appropriate inventory that does not violate the appropriate upper limit value of inventory by comparing the appropriate inventory calculated by the appropriate inventory calculation means and the appropriate upper limit value of inventory calculated by the appropriate upper limit value calculation means. means and
The appropriate inventory calculation means calculates an appropriate inventory for each grouping pattern using a plurality of grouping patterns with different combinations of the inventory management meshes,
The appropriate inventory determination means determines appropriate inventory to be held at the delivery destination, out of the appropriate inventory for each grouping pattern calculated by the appropriate inventory calculation means, which does not violate the appropriate upper limit value of inventory . Appropriate inventory determination support device characterized by
[ 2 ] said input means further inputs attribute information for each of said objects and inventory record information for each of said objects;
Appropriate inventory determination support apparatus according to [ 1 ], further comprising inventory control mesh setting means for setting an inventory control mesh using the attribute information and the actual inventory information.
[ 3 ] The inventory management mesh setting means divides the plurality of objects into groups based on the attribute information, and sets the inventory management mesh according to the out-of-stock probability calculated for each group using the actual inventory information. Appropriate inventory determination support device according to [ 2 ], characterized by setting
[ 4 ] The appropriate inventory determination support device according to [ 2 ] or [ 3 ], wherein the inventory management mesh setting means performs grouping in order from fine grouping to coarse grouping based on the attribute information. .
[ 5 ] The input means further inputs average usage information for each of the objects,
Safety stock calculation means for calculating safety stock using the transportation performance information and the average usage information,
The appropriate inventory calculation means calculates a cycle inventory, which is a running inventory, by using the arrival amount included in the delivery performance information, and adds the cycle inventory to the safety stock calculated by the safety stock calculation means to calculate an appropriate inventory. The appropriate inventory determination support device according to any one of [1] to [ 4 ], characterized by:
[ 6 ] The safety stock calculation means calculates the number of safety stock days by estimating a parameter, assuming that the transportation interval included in the transportation performance information follows a gamma distribution, and calculates the safety stock using the average usage amount information. The appropriate inventory determination support device according to [ 5 ], characterized by:
[ 7 ] The proper inventory upper limit calculation means calculates the maximum arrival amount per predetermined period by tweedie, assuming that the delivery timing included in the delivery performance information follows the Poisson distribution and the arrival amount included in the delivery performance information follows the gamma distribution. The appropriate inventory determination support device according to any one of [1] to [ 7 ], wherein the appropriate inventory upper limit value is calculated from the relationship between the storage capacity upper limit value and the storage capacity upper limit value.
[ 8 ] An appropriate inventory determination support method for assisting in determining an appropriate inventory to be held at a destination to which a plurality of objects are transported,
a step in which the input means inputs the transport performance information for each of the objects and the storage capacity upper limit value of the transport destination;
Appropriate inventory calculation means calculates an inventory management mesh grouping the objects for each delivery destination by using the safety inventory held so as not to cause a shortage even if supply and demand fluctuates and the delivery record information. a step of calculating an appropriate inventory for each delivery destination as a unit ;
a step of calculating an appropriate upper limit value of inventory based on the maximum amount of goods received per predetermined period calculated using the transportation performance information and the upper limit value of storage capacity;
Appropriate inventory determination means compares the appropriate inventory calculated by the appropriate inventory calculation means with the appropriate inventory upper limit calculated by the appropriate inventory upper limit value calculation means to determine the appropriate inventory that does not violate the appropriate inventory upper limit value. and determining
The appropriate inventory calculation means calculates an appropriate inventory for each grouping pattern using a plurality of grouping patterns with different combinations of the inventory management meshes,
The appropriate inventory determination means determines appropriate inventory to be held at the delivery destination, out of the appropriate inventory for each grouping pattern calculated by the appropriate inventory calculation means, which does not violate the appropriate upper limit value of inventory . Appropriate inventory determination support method characterized.
[ 9 ] A program for supporting determination of appropriate inventory to be held at a destination to which a plurality of objects are transported,
input means for inputting transportation performance information for each object and storage capacity upper limit value of the transportation destination;
Using the safety inventory held so as not to cause a shortage even if demand and supply fluctuates and the transportation performance information , the inventory management mesh grouping the objects for each transportation destination is used as a calculation unit, and the transportation destination an appropriate inventory calculation means for calculating an appropriate inventory for each
Appropriate inventory upper limit value calculation means for calculating an appropriate upper limit inventory value based on the maximum arrival amount per predetermined period calculated using the transportation performance information and the upper limit storage capacity;
Appropriate inventory determination for determining an appropriate inventory that does not violate the appropriate upper limit value of inventory by comparing the appropriate inventory calculated by the appropriate inventory calculating means with the appropriate upper limit value of inventory calculated by the upper limit value of appropriate inventory calculating means. make the computer work as a means ,
The appropriate inventory calculation means calculates an appropriate inventory for each grouping pattern using a plurality of grouping patterns with different combinations of the inventory management meshes,
The appropriate inventory determination means determines appropriate inventory to be held at the delivery destination, out of the appropriate inventory for each grouping pattern calculated by the appropriate inventory calculation means, which does not violate the appropriate upper limit value of inventory. Program characterized .

According to the present invention, it is possible to rationally determine the appropriate inventory based on the storage capacity of the delivery destination.

It is a figure which shows the functional structure of the appropriate inventory determination support apparatus which concerns on this embodiment. It is a flowchart which shows the appropriate inventory determination support method by the appropriate inventory determination support apparatus which concerns on this embodiment. It is a figure which shows the result of having set the inventory management mesh. It is a figure which shows the result of having set the inventory management mesh. FIG. 10 is a diagram showing a histogram showing arrival intervals of ships to destinations and an approximated curve based on gamma distribution; FIG. 10 is a diagram showing a histogram showing arrival intervals of ships to destinations and an approximated curve by exponential distribution; FIG. 10 is a diagram showing a histogram of the amount of goods received at a destination and an approximated curve based on a gamma distribution; FIG. 10 is a diagram showing the result of obtaining the occurrence probability of random variable W (t=1) per day; FIG. 10 is a diagram showing the results of inventory changes obtained by setting initial inventory so that the average inventory at the delivery destination matches the appropriate upper limit of inventory, and simulating a ship allocation plan; It is a figure for demonstrating the concept of appropriate inventory.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing the functional configuration of an appropriate inventory determination support device 100 according to this embodiment.
Appropriate inventory determination support device 100 targets a plurality of objects and a plurality of delivery destinations and determines the appropriate inventory to be held at each delivery destination. Appropriate inventory determination support device 100 includes an input unit 101, an inventory management mesh setting unit 102, a safety stock calculation unit 103, an appropriate inventory calculation unit 104, an appropriate inventory upper limit value calculation unit 105, an appropriate inventory determination unit 106, and an output unit 107 . The appropriate inventory determination support device 100 also includes an input device 201 such as a pointing device or keyboard, and an output device 202 such as a display. A storage device 300 is connected to the appropriate inventory determination support device 100 .

The storage device 300 stores and manages information used to determine appropriate inventory. The information stored and managed by the storage device 300 includes, although the details will be described later, information on actual transportation results for each transportation destination, average usage information for each transportation destination and for each brand, and actual inventory performance for each transportation destination and each brand. information, attribute information for each brand, and storage capacity upper limit value for each destination (hereinafter referred to as yard capacity upper limit value). A brand is an object name, which identifies the object.

Input unit 101 retrieves information used to determine appropriate inventory from storage device 300 .

The inventory management mesh setting unit 102 sets an inventory management mesh for each delivery destination using attribute information for each brand and inventory performance information for each delivery destination and each brand. The inventory management mesh is obtained by grouping a plurality of brands and aggregating them as necessary, and the safety stock and appropriate inventory are calculated using the inventory management mesh set here as a calculation unit. The inventory management mesh setting unit 102 sets a plurality of grouping patterns (FIGS. 3 and 4 to be described later) with different combinations of inventory management meshes.

The safety stock calculation unit 103 uses the actual transportation record information for each transportation destination and the average usage amount information for each transportation destination and for each brand in units of the inventory management mesh set by the inventory management mesh setting unit 102. Calculate the safety stock that should be held ahead. Safety stock is stock that is held to prevent shortages even if supply and demand fluctuates.

Appropriate inventory calculation unit 104 calculates cycle inventory, which is running inventory, in units of inventory management mesh set by inventory management mesh setting unit 102, using delivery performance information for each delivery destination, and safety stock calculation unit 103 Add the calculated safety stock to calculate the appropriate stock.

Appropriate inventory upper limit value calculation unit 105, based on the maximum arrival amount per predetermined period (for example, per day) calculated using the delivery performance information for each delivery destination and the yard capacity upper limit value for each delivery destination, Calculate the appropriate inventory upper limit for each destination.

The appropriate inventory determination unit 106 compares the appropriate inventory calculated by the appropriate inventory calculation unit 104 with the appropriate inventory upper limit calculated by the appropriate inventory upper limit value calculation unit 105, and determines the appropriate inventory that does not violate the appropriate inventory upper limit value. is determined as an appropriate stock to be held at each delivery destination.

The output unit 107 outputs the calculation results of each unit, for example, the appropriate inventory calculated by the appropriate inventory calculation unit 104, the appropriate inventory upper limit calculated by the appropriate inventory upper limit calculation unit 105, the appropriate inventory determined by the appropriate inventory determination unit 106 Output inventory. The output here means, for example, displaying on the output device 202 or transmitting to a computer device or storage device external to the apparatus 100 .

FIG. 2 is a flow chart showing an appropriate inventory determination support method by the appropriate inventory determination support device 100 according to this embodiment.
At step S1, the input unit 101 retrieves information used to determine appropriate inventory from the storage device 300. FIG.
Table 1 shows an example of transport performance information for each transport destination. For each transport destination, the arrival time (in the case of transport by ship, the time of arrival at the port), the quantity received [1,000 tons], and the brand are recorded.

Table 2 shows an example of average usage information for each destination and for each brand. The average usage amount per day [1,000 tons/day] is recorded for each destination and each brand.

Table 3 shows an example of inventory record information for each delivery destination and for each brand. For each delivery destination and each brand, the date and the inventory amount [1,000 tons] on that date are recorded.

Table 4 shows an example of attribute information for each brand. In this embodiment, there are three types of attribute information for each brand: a quality group, a component group, and a classification group. If the object is a raw material in the steel industry, the classification group is grouped by classification such as pellets, fine ore, lump ore, and the like. The component group is grouped by components such as alumina, acidity, and basicity, and is divided into a plurality of cases. A quality group is a grouping by quality based on overall indices such as shape, in addition to classification and components. The quality group is the most detailed, the ingredient group is the second most detailed, and the classification group information is the coarsest grouping.

Table 5 shows an example of the upper limit of yard capacity for each destination. A yard capacity (the upper limit of objects that can be placed in the yard) [1,000 tons] is set for each destination as the yard capacity upper limit.

In step S2, the inventory management mesh setting unit 102 uses the attribute information for each brand (Table 4) input in step S1 and the inventory record information for each destination and each brand (Table 3) to determine the delivery destination. Set the inventory management mesh for each.
The inventory management mesh setting unit 102 uses the attribute information for each brand in Table 4 to determine the presence or absence of inventory management for each group from performance data, and sets the inventory management mesh. To determine whether there is inventory management at the delivery destination, the inventory performance of each brand is totaled every day during the analysis target period, and after calculating the number of days when the inventory is 0 or less at the end of the day (out-of-stock days), the analysis target Calculate the out-of-stock probability by dividing by the period. In the present embodiment, the analysis target period is the data of the previous year to be analyzed, and the management mesh is set as inventory management when the out-of-stock probability is within 5%. Note that the determination of the presence or absence of inventory management is not limited to this method. For example, inventory changes may be simulated from future production plans, and the presence or absence of inventory management may be determined from the results.

As an example, using the quality group, classification group, and component group case 1 of the attribute information for each brand in Table 4, setting an inventory management mesh for each destination will be described. FIG. 3 shows the result of setting an inventory management mesh for each delivery destination using the quality group, classification group, and component group case 1 of the attribute information for each brand in Table 4. FIG.
Here, the description will focus on the transport destination 3 . First, the inventory management mesh setting unit 102 determines the presence or absence of inventory management for each of the finest quality groups. As shown in FIG. 3, at the delivery destination 3, quality 11 is judged to be in stock (probability of out-of-stock within 5%), is designated for individual management, and is set in the inventory management mesh.
Next, the inventory management mesh setting unit 102 determines the presence or absence of inventory management for each component group case 1 . At this time, since quality 11 has already been set as an inventory control mesh for component 8, the presence or absence of inventory control is determined for the group (quality 10) obtained by excluding brands belonging to quality 11 from the group of component 8. do. As shown in FIG. 3, at delivery destination 3, component 1, component 7, component 9, and component 10 are determined to be in stock (out-of-stock probability within 5%), and are set in the inventory management mesh.
Next, the inventory management mesh setting unit 102 determines the presence or absence of inventory management for each of the coarsest classification groups. At this time, for Category 1, Component 1 has already been set as an inventory control mesh, so it is determined whether or not inventory control is performed for a group (Quality 3) obtained by excluding brands belonging to Component 1 from the Category 1 group. do. For Class 3, Quality 11, Component 7, Component 9, and Component 10 have already been set as an inventory management mesh. The presence or absence of inventory management is determined for the groups (quality 10, quality 16) excluding the brands belonging to . As shown in FIG. 3, at destination 3, classification 2 is determined to have inventory determination (out-of-stock probability is within 5%), and is set in the inventory management mesh.
As shown in white in FIG. 3, for groups that have not been selected to the end, the safety stock is set to 0 and the appropriate stock is calculated based on the actual stock. It should be noted that the method of inventory management for groups that have not been selected to the end is not limited to this method. For example, the actual out-of-stock probability may be calculated, the guarantee rate may be set based on the probability, and the safety stock may be determined.

FIG. 4 shows the result of setting an inventory management mesh for each delivery destination using the quality group, classification group, and component group case 2 of the attribute information for each brand in Table 4. FIG.
In the grouping pattern of FIG. 3, quality 8 and 9 and quality 12 and 13 are managed as separate groups. On the other hand, in the grouping pattern of FIG. 4, qualities 8 and 9 and qualities 12 and 13 are managed as the same group. Strictly speaking, quality 8 and 9 and quality 12 and 13 differ in composition, but they are brands that can be substituted for a certain amount. .

The inventory management mesh set here is used as a calculation unit to calculate the subsequent safety stock and proper stock. In the grouping pattern of FIG. 3, at destination 3, safety stock and proper stock are calculated for component 1 (quality 1 and quality 2 are aggregated). In addition, the safety stock and appropriate stock are calculated for classification 2 (aggregating quality 4 to 7). In addition, the safety stock and proper stock are calculated for component 7 (aggregate quality 8 and 9), component 9 (aggregate quality 12 and 13), and component 10 (aggregate quality 14 and 15). In addition, the quality 11 calculates the safety stock and proper stock. Also, the safety stock and proper stock are calculated with the quality 3 as "classification 1 other". Also, the safety stock and proper stock are calculated with the quality 10 and 16 as "classification 3 other".

In this way, by assigning attributes such as quality group, classification group, and ingredient group to each brand, and calculating inventory transitions from performance data based on these attributes, inventory management should calculate appropriate inventory according to the characteristics of each delivery destination. You can set the mesh.
In addition, by setting a plurality of component groups, it is possible to consider appropriate inventory on the premise of a plurality of components. Since the grouping pattern in FIG. 4 has a coarser inventory management mesh than the grouping pattern in FIG. 3, it is expected that the proper inventory to be managed will decrease.

For example, Patent Literature 1 discloses grouping based on usage information for each brand (an average value of the number of parts used per unit time as referred to in Patent Literature 1). If this is applied as it is, there is a risk that different brands that cannot be managed in the same way will be managed in the same way in actual operation, and the operation will become unstable due to the lack of stock of the necessary brand. In contrast, in the present embodiment, attributes such as a quality group, a classification group, and an ingredient group are given to each brand, and an inventory management mesh is set based on these attributes. You can set up an inventory management mesh with objects. As a result, it is possible to maintain stable operations by setting an appropriate inventory that protects the inventory management mesh.

In step S3, the safety stock calculation unit 103 calculates, in units of the inventory management mesh set in step S2, the transportation result information (Table 1) for each transportation destination input in step S1, and the average for each transportation destination and each brand. The usage information (Table 2) is used to calculate the safety stock to be held at each delivery destination.
In this embodiment, for each destination and for each inventory management mesh, it is assumed that the interval at which ships arrive at the destination (i.e., the transportation interval) follows a gamma distribution. Then, the safety stock was calculated by multiplying the safety stock days by the average usage in Table 2.

FIG. 5 is a diagram showing, in the grouping pattern of FIG. 3, a histogram showing the arrival interval of ships to the destination 3 for each inventory management mesh, and an approximated curve by gamma distribution, where the horizontal axis is the arrival interval [ day], and the vertical axis indicates the number of arrivals.
In the grouping pattern of FIG. 3, at destination 3, component 1 (quality 1 and 2 are aggregated), category 2 (quality 4 to 7 are aggregated), component 7 (quality 8 and 9 are aggregated), component 9 (quality 12 and 13), Component 10 (Quality 14 and 15 are aggregated), Quality 11, Category 1 Others (Quality 3), Category 3 Others (Quality 10 and 16 are aggregated) to calculate the safety stock as an inventory control mesh. . At this time, the number of safety stock days described above calculates the difference between the average arrival pitch and the reliability point from the gamma distribution model. As the reliability point, the gamma distribution is a point that covers the ratio of the guarantee rate, and basically the guarantee rate is set to 95%. If the actual shortage rate is 5% or more, the guarantee rate is obtained by 100 minus the actual shortage rate, and the reliability score of the gamma distribution is calculated using the guarantee rate. As a specific example, in the approximation curve of the gamma distribution in FIG. 5, the hatched area is the area that covers 95% of the gamma distribution. For the average arrival pitch, the average value of the approximation curve by gamma distribution should be given. Calculation of safety stock is not limited to this method. For example, the standard deviation of ship arrival intervals may be calculated, and double the standard deviation may be given as the safety stock.

In step S4, the appropriate inventory calculation unit 104 calculates cycle inventory, which is running inventory, using the delivery record information for each delivery destination input in step S1, in units of the inventory management mesh set in step S2, and The appropriate stock is calculated by adding it to the safety stock calculated in step S3.
For each inventory management mesh unit, the average arrival amount is calculated from the transport record information in Table 1, and one half of it is given as the cycle inventory as shown in Equation (1).
Cycle inventory = average amount received / 2 (1)
Then, as described with reference to FIG. 10, the appropriate inventory is calculated by adding the safety inventory calculated in step S3 and the cycle inventory obtained by the formula (1).

Table 6 shows the result of calculating the appropriate inventory to be held at each delivery destination (total value of appropriate inventory calculated for each inventory management mesh) in the grouping pattern of FIG. Table 7 shows the result of calculating the appropriate inventory to be held at each delivery destination (total value of appropriate inventory calculated for each inventory management mesh) in the grouping pattern of FIG. In this way, it is possible to calculate the appropriate inventory to be held at each delivery destination.

In step S5, the proper inventory upper limit value calculation unit 105 calculates the maximum amount of goods received per day using the actual delivery information for each destination input in step S1. Based on the yard capacity upper limit value for each transfer destination input in step S1, the proper inventory upper limit value for each transfer destination is calculated.
Too much inventory causes yard overflow, but too little inventory can lead to quality deterioration and troubles due to shortages. Therefore, it is preferable to set the appropriate inventory to an amount that does not exceed the storage capacity of the delivery destination. Therefore, in consideration of the storage capacity of the delivery destination and the variation in arrival intervals of ships and the amount of incoming goods, the inventors came up with the idea of finding an appropriate upper limit value of inventory that does not exceed the storage capacity of the delivery destination. Calculate the maximum amount of goods received per day expected at each destination, and set the value obtained by subtracting the maximum amount of goods received from the yard capacity as the appropriate inventory upper limit.

First, the maximum arrival amount is calculated using the port arrival time for each destination. In this embodiment, in the arrival process {N(t), t≧0} of a ship arriving at a destination, the arrival intervals {X ₁ , X ₂ , . Let (t) be a random variable with t≧0. Also, the arrival amount of ships _{{ Y 1} , Y ₂ , . x}.
Under this assumption, the random variable W(t) of the total arrival amount value at a certain time t≧0 (t=0, 1, 2, . . . ) is represented by Equation (2).

{W(t), t≧0} is a stochastic process called a complex process. In order to calculate the maximum amount of incoming goods, after obtaining the distribution followed by the arrival event (i.e., delivery timing) for each destination and the distribution followed by the incoming amount, a random variable W(t) is obtained, Calculate the maximum shipment amount.
In the present embodiment, the composite process {W(t), t≧0} was calculated on the assumption that the number of ship arrivals per day follows Poisson distribution and the amount of arrival follows gamma distribution. A stochastic process in which the number N of occurrences of events follows a Poisson distribution and each event Y _k follows a gamma distribution is called a tweedie distribution. An arrival process whose number of occurrences follows the Poisson distribution is called a Poisson process.

FIG. 6 is a diagram showing a histogram showing arrival intervals of ships at the destination 3 and an approximated curve by exponential distribution, in which the horizontal axis indicates the arrival intervals [days] and the vertical axis indicates the frequency. It is known that arrival intervals of arrival events according to the Poisson process follow an exponential distribution, and finding the parameter λ of the exponential distribution corresponds to finding the only parameter λ of the Poisson process. After extracting the data related to the destination 3 from the transportation result information for each destination in Table 1, the parameter λ was estimated using the maximum likelihood estimation method for the arrival interval data that can be calculated from the difference in the arrival times. As a result, the parameter λ at destination 3 was 0.32. Data for one year was used for the analysis.

FIG. 7 is a diagram showing a histogram of the arrival amount at the destination 3 and an approximation curve based on the gamma distribution, in which the horizontal axis indicates the arrival amount [tons] and the vertical axis indicates the frequency. The gamma distribution is known to be suitable as a modeling method for distributions with a long tail on the right side. It is a distribution defined by two types of parameters. Γ(α) is the gamma function, and x is the amount of goods received. After extracting the data related to destination 3 from the delivery performance information for each destination in Table 1, the gamma distribution parameter estimation was performed by nonlinear regression analysis using the least squares method for the data of the amount of arrivals. The shape parameter α and scale parameter θ at destination 3 were estimated to be 1.3×10 ⁻⁴ and 12.0, respectively. Data for one year was used for the analysis.

FIG. 8 shows the result of obtaining the occurrence probability of the random variable W (t=1) per day with t=1 based on the parameters of the exponential distribution and the gamma distribution estimated from the actual transportation information for each destination. . W(t=1) represents a random variable of the total amount of arrivals from time 0 [day] to time 1 [day]. did. It can be seen that the daily arrival amount at the destination 3 is the largest around 100000 [tons]. A point that covers 99% of the occurrence probability of the random variable W (t=1) is defined as the maximum arrival amount, and as a result of calculating it, a calculation result of 226595 [tons] was obtained.

As shown in Table 8, for example, the upper limit of the yard capacity of destination 3 is 900 [1,000 tons]. You can be assured that the destination yard capacity will not be exceeded.

Fig. 9 shows the inventory changes obtained by setting the initial inventory so that the average inventory at the delivery destination 3 coincides with the proper inventory upper limit of 673 [1,000 tons] and simulating the ship allocation plan. It is a figure which shows a result. As shown in FIG. 9, the rate of inventory exceeding the yard capacity upper limit (yard overflow rate) is 2.4%. A large yard overflow did not occur, confirming that the upper limit of operable inventory was reached.

In step S6, the appropriate inventory determination unit 106 compares the appropriate inventory calculated in step S4 with the appropriate upper limit of inventory for each destination calculated in step S5, and determines the appropriate inventory that does not violate the upper limit of appropriate inventory. is determined as an appropriate stock to be held at each delivery destination.
For the inventory control mesh, the appropriate inventory and the appropriate upper limit of inventory are compared at each destination, and the mesh whose appropriate inventory is equal to or less than the appropriate upper limit of inventory and is closest to the upper limit of appropriate inventory is adopted. For example, as shown in Table 6, destination N's appropriate inventory of 989.5 exceeds the destination N's appropriate inventory upper limit value 802 shown in Table 8. Therefore, it is determined that the inventory control mesh used to calculate Table 6 cannot be adopted at destination N. On the other hand, as shown in Table 7, the proper inventory 616.6 of the destination N is below the proper inventory upper limit 802 of the destination N shown in Table 8. Therefore, it is determined that the inventory management mesh used to calculate Table 7 can be adopted at destination N. In this way, in comparing component case 1 and component case 2, the mesh by component case 2 is determined as the inventory management mesh.

At step S7, the output unit 107 outputs the results of each step (FIGS. 3 to 9 and Tables 6 to 8).

As described above, using multiple grouping patterns with different methods of grouping multiple brands (combination of inventory management meshes), appropriate inventory is calculated for each of these grouping patterns, and By obtaining the appropriate upper limit of inventory, it is possible to determine the appropriate inventory to be held at each destination without consolidating brands too much based on the storage capacity of the destination. In the past, the relationship between the appropriate inventory and the storage capacity upper limit (yard capacity) of the delivery destination was unknown, so if the appropriate inventory was set to greatly exceed the yard capacity, there was a possibility of causing a large yard waiting delay. did. By applying the method of this embodiment, it is possible to calculate an inventory management mesh and an appropriate inventory that does not exceed the appropriate upper limit value of inventory considering the yard capacity. In addition, the inventory management mesh can be set to an amount that is below the appropriate upper limit of inventory, but as close to the appropriate upper limit of inventory as possible.

As described above, the present invention has been described together with the embodiments, but the above-described embodiments merely show specific examples for carrying out the present invention, and the technical scope of the present invention is not construed in a limited manner. It should not be. That is, the present invention can be embodied in various forms without departing from its technical concept or main features.
For example, in the above embodiment, the appropriate inventory determination support device 100 has the appropriate inventory determination unit 106, but the appropriate inventory determination unit 106 may not be provided. It is possible to assist the user in determining the appropriate inventory simply by presenting the calculation results of the appropriate inventory calculation unit 104 and the appropriate inventory upper limit value calculation unit 105 to the user.

Appropriate inventory determination support apparatus to which the present invention is applied is realized by a computer device equipped with, for example, a CPU, a ROM, a RAM, and the like. Although the appropriate inventory determination support device 100 is illustrated as one device in FIG. 1, it may be configured by a plurality of devices, for example.
In addition, the present invention can also be achieved by supplying software (program) that realizes the functions of the present invention to a system or device via a network or various storage media, and reading and executing the program by the computer of the system or device. It is feasible.

100: Appropriate inventory determination support device 101: Input unit 102: Inventory control mesh setting unit 103: Safety stock calculation unit 104: Appropriate inventory calculation unit 105: Appropriate inventory upper limit value calculation unit 106: Appropriate inventory determination unit 107: Output unit

Claims (9)

An appropriate inventory determination support device for assisting determination of an appropriate inventory to be held at a destination to which a plurality of objects are transported,
an input means for inputting transportation record information for each object and an upper limit value of storage capacity of the transportation destination;
Using the safety inventory held so as not to cause shortages even if demand and supply fluctuates, and the transportation performance information , the inventory management mesh grouping the objects for each transportation destination is used as a calculation unit, and the transportation destination an appropriate inventory calculation means for calculating an appropriate inventory for each
Appropriate upper limit inventory value calculation means for calculating an appropriate upper limit value of inventory based on the maximum amount of incoming goods per predetermined period calculated using the transportation performance information and the upper limit value of storage capacity;
Appropriate inventory determination for determining an appropriate inventory that does not violate the appropriate upper limit value of inventory by comparing the appropriate inventory calculated by the appropriate inventory calculation means and the appropriate upper limit value of inventory calculated by the appropriate upper limit value calculation means. means and
The appropriate inventory calculation means calculates an appropriate inventory for each grouping pattern using a plurality of grouping patterns with different combinations of the inventory management meshes,
The appropriate inventory determination means determines appropriate inventory to be held at the delivery destination, out of the appropriate inventory for each grouping pattern calculated by the appropriate inventory calculation means, which does not violate the appropriate upper limit value of inventory . Appropriate inventory determination support device characterized by the input means further inputs attribute information for each of the objects and inventory performance information for each of the objects;
2. The appropriate inventory determination support device according to claim 1 , further comprising inventory control mesh setting means for setting an inventory control mesh using said attribute information and said inventory record information. The inventory management mesh setting means groups the plurality of objects based on the attribute information, and sets the inventory management mesh according to the out-of-stock probability calculated for each group using the actual inventory information. Appropriate inventory determination support device according to claim 2 , characterized by: 4. The appropriate inventory determination support device according to claim 2 , wherein said inventory management mesh setting means performs grouping in order from fine grouping to coarse grouping based on said attribute information. The input means further inputs average usage information for each of the objects,
Safety stock calculation means for calculating safety stock using the transportation performance information and the average usage information,
The appropriate inventory calculation means calculates a cycle inventory, which is a running inventory, by using the arrival amount included in the delivery performance information, and adds the cycle inventory to the safety stock calculated by the safety stock calculation means to calculate an appropriate inventory. 5. Appropriate inventory determination support device according to any one of claims 1 to 4 , characterized in that: The safety stock calculation means calculates the number of safety stock days by estimating a parameter, assuming that the transportation interval included in the transportation performance information follows a gamma distribution, and calculates the safety stock using the average usage amount information. Appropriate inventory determination support device according to claim 5 . The proper inventory upper limit value calculation means calculates the maximum arrival amount per the predetermined period by tweedie distribution, assuming that the delivery timing included in the delivery performance information follows Poisson distribution and the arrival amount included in the delivery performance information follows gamma distribution. 7. The appropriate inventory determination support device according to any one of claims 1 to 6 , wherein the appropriate inventory upper limit value is calculated from the relationship between the storage capacity upper limit value and the storage capacity upper limit value. An appropriate inventory determination support method for assisting determination of an appropriate inventory to be held at a destination to which a plurality of objects are transported, comprising:
a step in which the input means inputs the transport performance information for each of the objects and the storage capacity upper limit value of the transport destination;
Appropriate inventory calculation means calculates an inventory management mesh grouping the objects for each delivery destination by using the safety inventory held so as not to cause a shortage even if supply and demand fluctuates and the delivery record information. a step of calculating an appropriate inventory for each delivery destination as a unit ;
a step of calculating an appropriate upper limit value of inventory based on the maximum amount of goods received per predetermined period calculated using the transportation performance information and the upper limit value of storage capacity;
Appropriate inventory determination means compares the appropriate inventory calculated by the appropriate inventory calculation means with the appropriate inventory upper limit calculated by the appropriate inventory upper limit value calculation means to determine the appropriate inventory that does not violate the appropriate inventory upper limit value. and determining
The appropriate inventory calculation means calculates an appropriate inventory for each grouping pattern using a plurality of grouping patterns with different combinations of the inventory management meshes,
The appropriate inventory determination means determines appropriate inventory to be held at the delivery destination, out of the appropriate inventory for each grouping pattern calculated by the appropriate inventory calculation means, which does not violate the appropriate upper limit value of inventory . Appropriate inventory determination support method characterized. A program for supporting determination of appropriate inventory to be held at a delivery destination to which multiple objects are delivered,
an input means for inputting transportation record information for each object and an upper limit value of storage capacity of the transportation destination;
Using the safety inventory held so as not to cause shortages even if demand and supply fluctuates, and the transportation performance information , the inventory management mesh grouping the objects for each transportation destination is used as a calculation unit, and the transportation destination an appropriate inventory calculation means for calculating an appropriate inventory for each
Appropriate upper limit inventory value calculation means for calculating an appropriate upper limit value of inventory based on the maximum amount of incoming goods per predetermined period calculated using the transportation performance information and the upper limit value of storage capacity;
Appropriate inventory determination for determining an appropriate inventory that does not violate the appropriate upper limit value of inventory by comparing the appropriate inventory calculated by the appropriate inventory calculation means and the appropriate upper limit value of inventory calculated by the appropriate upper limit value calculation means. make the computer work as a means ,
The appropriate inventory calculation means calculates an appropriate inventory for each grouping pattern using a plurality of grouping patterns with different combinations of the inventory management meshes,
The appropriate inventory determination means determines appropriate inventory to be held at the delivery destination, out of the appropriate inventory for each grouping pattern calculated by the appropriate inventory calculation means, which does not violate the appropriate upper limit value of inventory. Program characterized .

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