JP2020017127A - Proper inventory determination support apparatus, method thereof, and program therefor - Google Patents

Abstract

To reasonably determine proper inventory in consideration of storage capacity of a conveyance destination.SOLUTION: A proper inventory determination support apparatus 100 according to the present invention determines proper inventory which each conveyance destination should keep, with respect to a plurality of objects and a plurality of conveyance destinations. A safe inventory calculating unit 103 calculates, by a set unit of inventory management mesh, safe inventory which each conveyance destination should keep (inventory which it should have and does not lead to lack of inventory even if the demand and supply is fluctuated) by using conveyance result information of each conveyance destination and average use amount information of each conveyance destination and each article. A proper inventory calculating unit 104 calculates a cycle inventory which is a running inventory, by using the conveyance result information of each conveyance destination by the unit of inventory management mesh, and calculates a proper inventory by adding the cycle inventory and the safe inventory. A proper inventory upper limit value calculating unit 105 calculates a proper inventory upper limit value of each conveyance destination on the basis of the maximum arrival amount, e.g., per day, calculated by using the conveyance result information of each conveyance destination and a yard capacity upper limit value of each conveyance destination.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an appropriate stock determination support device, a method, and a program that support determination of an appropriate stock to be held at a destination to which a plurality of objects are transferred.

  Steel manufacturers, chemical manufacturers, petroleum manufacturers, electric power companies, etc. ship objects such as raw materials, materials, products, and commodities to shipping destinations (eg, delivery destinations) such as factories, commercial facilities, and inventory bases, for example, by ship from overseas. Import and store as stock at the destination. Excessive inventory causes a slowdown in cash flow and an increase in management costs. On the other hand, if the stock is too small, it may lead to a reduction in production or a stoppage of production due to deterioration in quality or out of stock.

  In order to avoid excessive or insufficient inventory, it is desirable to evaluate the variation in supply and demand of the target object and set an average inventory (referred to as appropriate inventory) as a management target. With reference to FIG. 10, the concept of proper stock will be described. FIG. 10 is a diagram for explaining the concept of the appropriate stock, where the horizontal axis indicates time, the vertical axis indicates the stock amount, and indicates a change in stock. The proper stock is a sum of a cycle stock, which is a running stock having only a constant fluctuation of the stock, and a safety stock which does not cause out-of-stock even if demand and supply vary (Non-Patent Document 1). checking). By determining the appropriate stock, it is possible to prevent quality deterioration and out-of-stock items while preventing a slowdown in cash flow and an increase in management costs.

As this type of technology, for example, in Patent Document 1, a safety stock ratio is calculated based on a predicted amount of past demand and an actual amount, and a safety stock is calculated by multiplying a predicted amount of future demand by the safety stock ratio. In the safety stock calculation method, it is determined whether the calculated safety stock ratio exceeds a predetermined upper limit value, and when the calculated safety stock ratio exceeds the upper limit value, the calculated safety stock ratio is multiplied by the upper limit value instead of the calculated safety stock ratio. A method for calculating safety stock is disclosed.
In addition, Patent Document 2 discloses that a standard deviation model is formed by grouping a plurality of types of parts by a predetermined method in order to appropriately calculate a safety stock of a large variety of small-quantity products, and using each part group as a population. A method of calculating the safety stock of each component from the standard deviation model of each component group and a preset safety coefficient of each component is disclosed.
It should be noted that both of the above-mentioned Patent Documents 1 and 2 can use the appropriate stock calculation method of Non-Patent Document 1 to calculate the proper stock by adding the cycle stock to the safety stock.

JP 2000-207479 A JP 2008-293319 A

Takao Katsuro, "Appropriate Inventory Concepts and How to Find It," published September 10, 2003, Nikkan Kogyo Shimbun

However, Patent Literature 1 does not show a reasonable setting method of the upper and lower limits of the safety stock ratio, and the upper and lower limits of the appropriate stock obtained from the calculation result of the safety stock depend on the intuition of the practitioner. Further, Patent Literature 2 discloses a method of setting safety stock by grouping, but does not 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 destination, the objects to be received cannot be stored, causing the vessel to stay at sea and penalties must be paid as an additional fee.
Therefore, the appropriate stock needs to be rationally determined based on the storage capacity of the destination. If the appropriate stock exceeds the storage capacity of the transport destination, it is required to reduce the number of objects to be managed, to collect alternative objects, and the like.

  The present invention has been made in view of the above points, and an object of the present invention is to enable a proper inventory to be determined rationally based on the storage capacity of a destination.

The gist of the present invention for solving the above problems is as follows.
[1] An appropriate stock determination support device that supports determining an appropriate stock to be held at a destination to which a plurality of objects are transferred,
Input means for inputting the transfer result information for each object, and the storage capacity upper limit value of the transfer destination,
Safety stock having not to be out of stock even if the supply and demand fluctuates, and proper stock calculation means for calculating the proper stock using the above-mentioned transport performance information,
A proper stock upper limit value calculating means for calculating a proper stock upper limit value based on the maximum arrival amount per predetermined period calculated using the transfer result information and the capacity upper limit value,
Appropriate stock determining means for comparing the proper stock calculated by the proper stock calculating means with the proper stock upper limit value calculated by the proper stock upper limit calculating means to determine proper stock which does not violate the proper stock upper limit value. A proper stock determination support device characterized by comprising:
[2] The proper stock determination support device according to [1], wherein the proper stock calculation means calculates a proper stock using a stock management mesh obtained by grouping the plurality of objects as a calculation unit.
[3] The suitable stock calculation means according to [2], wherein the proper stock calculation means calculates a proper stock for each of the grouping patterns by using a plurality of grouping patterns in which a combination of inventory management meshes is different. Appropriate stock decision support device.
[4] The input means further inputs attribute information for each of the objects, and actual stock information for each of the objects,
The appropriate stock determination support device according to [3], further comprising a stock management mesh setting unit that sets a stock management mesh using the attribute information and the stock performance information.
[5] The inventory management mesh setting means divides the plurality of objects into groups based on the attribute information, and sets an inventory management mesh according to an out-of-stock probability calculated using the inventory actual information. The proper stock determination support device according to [4], wherein:
[6] The appropriate stock determination support device according to [4] or [5], wherein the stock management mesh setting unit performs grouping in order from fine grouping to coarse grouping based on the attribute information. .
[7] The input unit further inputs average usage information for each of the objects,
A safety stock calculation means for calculating a safety stock using the transport result information and the average usage information,
The proper stock calculating means calculates a cycle stock which is a running stock using the received amount included in the transport result information, and calculates a proper stock by adding the safety stock calculated by the safety stock calculating means. The proper stock determination support device according to any one of [1] to [6], wherein:
[8] The safety stock calculation means calculates the safety stock days by estimating the parameters and calculating the safety stock using the average usage information, assuming that the transfer intervals included in the transfer result information follow the gamma distribution. The proper stock determination support device according to [7], wherein:
[9] The appropriate stock upper limit value calculating means determines that the maximum arrival amount per the predetermined period is tweedie, assuming that the conveyance timing included in the conveyance result information follows a Poisson distribution and the arrival amount included in the conveyance result information follows a gamma distribution. The appropriate stock determination support device according to any one of [1] to [8], wherein the calculation is performed by distribution and the appropriate stock upper limit is calculated from the relationship of the capacity upper limit.
[10] An appropriate stock determination support method for supporting determination of an appropriate stock to be held at a transport destination to which a plurality of objects are transported,
Input means, inputting the transfer result information for each of the objects, the storage capacity upper limit value of the destination,
Appropriate stock calculation means, a step of calculating a proper stock using the safety stock having not to be out of stock even if the supply and demand fluctuates, and the transport performance information,
An appropriate stock upper limit value calculating unit, based on the maximum arrival amount per a predetermined period calculated using the transfer result information and the capacity upper limit value, calculating an appropriate stock upper limit value;
The proper stock determining means compares the proper stock calculated by the proper stock calculating means with the proper stock upper limit calculated by the proper stock upper limit calculating means, and determines proper stock which does not violate the proper stock upper limit. Determining a proper stock.
[11] A program for supporting determination of an appropriate stock to be held at a destination to which a plurality of objects are transported,
A process of inputting the transfer result information for each of the objects, and a storage capacity upper limit value of the transfer destination,
A process of calculating a proper stock using the safety stock having not to cause a shortage even if the supply and demand varies, and the transfer result information;
A process of calculating an appropriate stock upper limit value based on the maximum arrival amount per predetermined period calculated using the transfer result information and the capacity upper limit value,
A program for causing a computer to execute a process of comparing the calculated proper stock with the calculated proper stock upper limit value to determine a proper stock that does not violate the proper stock upper limit value.

  According to the present invention, an appropriate stock can be rationally determined based on the storage capacity of a destination.

It is a figure showing functional composition of an appropriate stock decision support device concerning this embodiment. It is a flowchart which shows the proper stock determination support method by the proper stock determination support device according to the present embodiment. It is a figure showing the result of having set up an inventory management mesh. It is a figure showing the result of having set up an inventory management mesh. It is a figure which shows the histogram which shows the arrival interval of the ship to the destination, and the approximate curve by gamma distribution. It is a figure which shows the histogram which shows the arrival interval of the ship to the destination, and the approximate curve by an exponential distribution. It is a figure which shows the histogram of the arrival amount of a conveyance destination, and the approximate curve by gamma distribution. It is a figure showing the result of having calculated | required the occurrence probability of the random variable W (t = 1) per day. It is a figure which shows the result of the stock transition obtained as a result of carrying out the simulation of a ship assignment plan by setting an initial stock so that the average stock of a transfer destination may correspond to an appropriate stock upper limit. It is a figure for explaining the idea of appropriate stock.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a functional configuration of an appropriate stock determination support device 100 according to the present embodiment.
The appropriate stock determination support device 100 determines appropriate stock to be held at each transport destination for a plurality of objects and a plurality of transport destinations. The proper stock determination support device 100 includes an input unit 101, a stock management mesh setting unit 102, a safety stock calculation unit 103, a proper stock calculation unit 104, a proper stock upper limit calculation unit 105, a proper stock determination unit 106, An output unit 107. The appropriate stock determination support device 100 includes an input device 201 such as a pointing device and a keyboard, and an output device 202 such as a display. The storage device 300 is connected to the appropriate stock determination support device 100.

  The storage device 300 stores and manages information used for determining an appropriate stock. The information stored and managed in the storage device 300 will be described later in detail, but will be described below. The actual transport information for each transport destination, the average usage amount information for each transport destination and each brand, and the actual inventory information for each transport destination and each brand Information, attribute information for each brand, and a storage capacity upper limit (hereinafter, referred to as a yard capacity upper limit) for each destination. The brand is an object name, and the object is specified by this.

  The input unit 101 fetches, from the storage device 300, information used for determining an appropriate stock.

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

  The safety stock calculation unit 103 uses the actual delivery information for each destination and the average usage amount information for each destination and each brand in units of the inventory management mesh set by the inventory management mesh setting unit 102 to perform each transport. Calculate the safety stock you need to have first. Safety stocks are stocks that are kept so that shortages do not occur even if supply and demand vary.

  The proper stock calculation unit 104 calculates the cycle stock, which is the running stock, using the transfer result information for each transfer destination in units of the stock management mesh set by the stock management mesh setting unit 102, and the safety stock calculation unit 103 The appropriate stock is calculated by adding the calculated safety stock.

  The appropriate stock upper limit calculation unit 105 calculates the maximum amount of arrival per predetermined period (for example, per day) calculated using the transfer result information for each destination, and the yard capacity upper limit for each destination. Calculate the appropriate upper limit of stock for each destination.

  The proper stock determining unit 106 compares the proper stock calculated by the proper stock calculating unit 104 with the proper stock upper limit calculated by the proper stock upper limit calculating unit 105, and determines the proper stock that does not violate the proper stock upper limit. Is determined as an appropriate stock to be held at each transport destination.

  The output unit 107 calculates the result of each unit, for example, the proper stock calculated by the proper stock calculating unit 104, the proper stock upper limit calculated by the proper stock upper limit calculating unit 105, and the proper stock determined by the proper stock determining unit 106. Output inventory. The output here means, for example, display on the output device 202 or sending to a computer device or a storage device external to the device 100.

FIG. 2 is a flowchart illustrating a proper stock determination support method by the proper stock determination support device 100 according to the present embodiment.
In step S1, the input unit 101 fetches, from the storage device 300, information used for determining an appropriate stock.
Table 1 shows an example of transfer result information for each transfer destination. For each transport destination, arrival time (arrival time in case of transport by ship), received quantity [1,000 tons], and brand are recorded.

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

  Table 3 shows an example of actual stock information for each destination and each brand. A date and a stock amount [thousand tons] at that date are recorded for each destination and each brand.

  Table 4 shows an example of attribute information for each brand. In the present embodiment, there are three types of attribute information for each brand: a quality group, a component group, and a classification group. When the object is a raw material or a material in the steel industry, the classification group is, for example, grouping by classification such as pellets, fine ore, lump ore, and the like. The component group is a grouping based on components such as alumina, acidic, and basic, and is divided into a plurality of cases. The quality group is a grouping based on quality based on a comprehensive index such as a shape in addition to the classification and components. The quality group is the finest, the component group is the next finer, and the classification group information is the coarsest grouping.

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

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 actual stock information for each destination and each brand (Table 3) to determine the destination. An inventory management mesh is set 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 the actual data, and sets an inventory management mesh. To determine the presence or absence of inventory management at the transport destination, during the analysis period, the inventory results of each brand are totaled for each day, and at the end of the day, the number of days when the inventory becomes 0 or less (out-of-stock days) is calculated, Calculate the out-of-stock probability by dividing by the period. In the present embodiment, the analysis target period is data for one year in the previous year to be analyzed, and when the out-of-stock probability is within 5%, a management mesh is set as having inventory management. It should be noted that the determination of the presence or absence of inventory management is not limited to this method. For example, a change in inventory may be simulated from a future production plan, and the presence or absence of inventory management may be determined from the result.

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

FIG. 4 shows the result of setting an inventory management mesh for each transport destination using the quality group, classification group, and component group case 2 of the attribute information for each brand in Table 4.
In the grouping pattern of FIG. 3, the qualities 8, 9 and the qualities 12, 13 are managed as separate groups. On the other hand, in the grouping pattern of FIG. 4, the qualities 8, 9 and the qualities 12, 13 are managed as the same group. Quality 8, 9 and quality 12, 13 are strictly different in components, but if they are a certain amount, they are brands that can be replaced. If the current components are treated as the same group, there is no major problem in operation. .

  With the stock management mesh set here as a unit of calculation, subsequent safety stock and proper stock are calculated. In the grouping pattern of FIG. 3, in the transport destination 3, the safety stock and the appropriate stock are calculated based on the component 1 (the quality 1 and 2 are aggregated). In addition, the safety stock and the appropriate stock are calculated according to the classification 2 (the quality 4 to 7 are aggregated). Further, the safety stock and the proper stock are calculated for each of the component 7 (the quality 8 and 9 are aggregated), the component 9 (the quality 12 and 13 are aggregated), and the component 10 (the quality 14 and 15 are aggregated). The safety stock and the appropriate stock are calculated based on the quality 11. Further, the safety stock and the appropriate stock are calculated with the quality 3 as “class 1 other”. In addition, the safety stock and the appropriate stock are calculated with the qualities 10 and 16 as “Category 3 Other”.

In this way, by assigning attributes such as quality group, classification group, and component group for each brand, and calculating the inventory transition from actual data based on the attributes, inventory management that should calculate the appropriate inventory according to the characteristics of each destination A mesh can be set.
In addition, by setting a plurality of component groups, it is possible to examine an appropriate stock based on a plurality of components. Since the inventory management mesh of the grouping pattern of FIG. 4 is coarser than that of the grouping pattern of FIG. 3, it is expected that the appropriate inventory to be managed is reduced.

  For example, Patent Literature 1 discloses that grouping is performed based on usage information for each brand (the average value of the number of components used per unit time referred to in Patent Literature 1). If this is applied as it is, a situation may arise in which different brands that cannot be managed identically in the actual operation are managed in the same manner, and the operation may become unstable due to stock out of necessary brands. On the other hand, in the present embodiment, attributes such as a quality group, a classification group, and a component group are assigned to each brand, and an inventory management mesh is set based on the attributes. An inventory management mesh can be set for an object. As a result, if an appropriate stock that protects the stock management mesh is set, the operation can be stably maintained.

In step S3, the safety stock calculation unit 103 determines, in units of the inventory management mesh set in step S2, the transport result information for each destination input in step S1 (Table 1) and the average for each destination and each brand. Using the usage information (Table 2), the safety stock to be held at each destination is calculated.
In this embodiment, for each transport destination and for each inventory management mesh, the intervals at which ships arrive at the transport destination (that is, transport intervals) follow the gamma distribution, and the safety stock days are calculated by estimating parameters from the actual data. Then, the safety stock was calculated by multiplying the average usage amount in Table 2 by the safety stock days.

FIG. 5 is a diagram showing a histogram indicating an arrival interval of a ship to the destination 3 and an approximate curve based on a gamma distribution for each inventory management mesh in the grouping pattern of FIG. The vertical axis indicates the number of arrivals.
In the grouping pattern of FIG. 3, at the transport destination 3, component 1 (quality 1 and 2 are aggregated), classification 2 (quality 4 to 7 are aggregated), component 7 (quality 8 and 9 are aggregated), component 9 (quality Calculate the safety stock using the inventory management mesh with the components 12 and 13), the component 10 (the quality 14 and 15 are aggregated), the quality 11, the class 1 and others (quality 3), and the class 3 and others (the quality 10 and 16 are aggregated). . At this time, for the above-mentioned safety stock days, the difference between the average arrival pitch and the reliability point is calculated from a gamma distribution model. As the reliability point, the gamma distribution is a point covering the ratio of the guarantee rate, and the guarantee rate is basically set to 95%. If the actual stockout rate is 5% or more, the guarantee rate is obtained from 100-the actual stockout rate, and the reliability point of the gamma distribution is calculated using the guarantee rate. As a specific example, in the approximation curve based on the gamma distribution in FIG. 5, a region hatched by oblique lines is a region covering 95% of the gamma distribution. The average arrival pitch may be an average value of the approximate curve based on the gamma distribution. The calculation of the safety stock is not limited to this method. For example, the standard deviation of the arrival intervals of ships may be calculated, and twice the standard deviation may be given as safety stock.

In step S4, the appropriate stock calculation unit 104 calculates the cycle stock, which is the running stock, for each stock management mesh set in step S2, using the transfer result information for each destination input in step S1, The appropriate stock is calculated by adding the safety stock calculated in step S3.
For each inventory management mesh, the average received quantity is calculated from the actual transport information shown in Table 1, and one half thereof is given as a cycle inventory as in equation (1).
Cycle inventory = average received quantity / 2 (1)
Then, as described with reference to FIG. 10, the appropriate stock is calculated by adding the safety stock calculated in step S3 and the cycle stock obtained by equation (1).

  Table 6 shows the results of calculating the appropriate stock to be held at each destination in the grouping pattern of FIG. 3 (total value of the appropriate stock calculated for each inventory management mesh). Table 7 shows the results of calculating the appropriate stock to be held at each transport destination in the grouping pattern of FIG. 4 (total value of the appropriate stock calculated for each inventory management mesh). In this way, it is possible to calculate the appropriate stock to be held at each destination.

In step S5, the appropriate stock upper limit value calculation unit 105 calculates the maximum arrival amount per day using the transfer result information for each destination input in step S1, and calculates the maximum arrival amount per day, Based on the yard capacity upper limit value for each destination input in step S1, the appropriate stock upper limit value for each destination is calculated.
If the inventory is too large, the yard will overflow, but if it is too small, there is a risk of causing quality deterioration and troubles due to shortage. Therefore, it is preferable to set the appropriate stock so as not to exceed the storage capacity of the destination. Therefore, in consideration of the storage capacity of the transport destination and the variation in the arrival intervals and the amount of arrival of the ships, the idea of finding an appropriate upper limit of stock that does not exceed the storage capacity of the transport destination was conceived. Calculate the expected maximum daily arrival amount at each destination, and set the value obtained by subtracting the maximum arrival amount from the yard capacity as the appropriate upper limit of stock.

First, the maximum arrival quantity is calculated using the arrival time at each destination. In the present embodiment, in the arrival process {N (t), t ≧ 0} of the ship to a certain destination, the arrival intervals {X ₁ , X ₂ ,...} Of each event are independent and have the same distribution F (T) It is assumed that the variable is a random variable having (t ≧ 0). Also, the arrival amount {Y ₁ , Y ₂ ,...} Of the ship at each arrival is the same distribution G (x) = P ｛Y _k ≦ independently of the arrival event and other Y _j (j ≠ k). Suppose that x｝ follows.
Under this assumption, the random variable W (t) of the total arrival amount at a certain time t ≧ 0 (t = 0, 1, 2,...) Is expressed as in Expression (2).

{W (t), t ≧ 0} is a stochastic process called a composite process. In order to calculate the maximum receiving quantity, a distribution according to an arrival event (that is, a transport timing) and a distribution according to the receiving quantity are obtained for each destination, and then a random variable W (t) is obtained. What is necessary is just to calculate the maximum receiving quantity.
In the present embodiment, the compound process {W (t), t ≧ 0} is calculated on the assumption that the number of times the ship arrives per day follows a Poisson distribution and the amount of arrival follows a gamma distribution. A stochastic process in which the number of occurrences N of an event follows a Poisson distribution and each event _Yk follows a gamma distribution is called a tweedie distribution. An arrival process in which the number of occurrences follows a Poisson distribution is called a Poisson process.

  FIG. 6 is a diagram showing a histogram indicating an arrival interval of a ship to the transport destination 3 and an approximate curve based on an exponential distribution. The horizontal axis indicates the arrival interval [day], and the vertical axis indicates the frequency. It is known that the arrival intervals of the arrival events according to the Poisson process follow an exponential distribution, and finding the parameter λ of the exponential distribution is equivalent to finding only the parameter λ of the Poisson process. After extracting the data relating to the transport destination 3 from the transport performance information for each transport destination in Table 1, the parameter λ was estimated using the maximum likelihood estimation method for the data of the arrival interval that can be calculated from the difference between the arrival times. As a result, the parameter λ at the transfer destination 3 was 0.32. The analysis used data for one year.

FIG. 7 is a diagram showing a histogram of the amount of arrival at the transport destination 3 and an approximate curve based on a gamma distribution. The horizontal axis indicates the amount of arrival [ton], and the vertical axis indicates the frequency. It is known that the gamma distribution is suitable as a modeling method for a distribution having a long tail on the right side. As shown in Expression (3), the probability density function G (x) has a scale parameter θ and a shape parameter α. It is a distribution defined by two types of parameters. Note that Γ (α) represents a gamma function, and x represents an amount received. After extracting data relating to the transport destination 3 from the transport performance information for each transport destination in Table 1, the results of estimating the parameters of the gamma distribution by non-linear regression analysis using the least squares method for the data of the arrival amount, The shape parameter α at the transfer destination 3 was estimated to be 1.3 × 10 ⁻⁴ , and the scale parameter θ was estimated to be 12.0. The analysis used data for one year.

  FIG. 8 shows the result of calculating the probability of occurrence of the random variable W (t = 1) per day as t = 1 based on the parameters of the exponential distribution and the gamma distribution estimated from the actual transport information for each destination. . W (t = 1) represents a random variable of the total amount of arrival from time 0 [day] to time 1 [day], and the total arrival amount W (0) at time t = 0 is 0 [ton]. did. It can be seen that the daily arrival at the transport destination 3 is the largest around 100,000 [tons]. A point covering 99% of the probability of occurrence of the random variable W (t = 1) was defined as the maximum amount of arrival, and as a result of calculation, a calculation result of 226595 [tons] was obtained.

  As shown in Table 8, for example, since the upper limit of the yard capacity of the transport destination 3 is 900 [1,000 tons], if the upper limit of the appropriate stock is 673 [1,000 tons], 99% of the average inventory is transported. You can guarantee that the yard capacity will not be exceeded.

  FIG. 9 shows an initial stock setting and a simulation of a ship assignment plan so that the average stock of the destination 3 matches the appropriate stock upper limit value of 673 [1,000 tons]. It is a figure showing a result. As shown in FIG. 9, the ratio of the stock exceeding the yard capacity upper limit (yard overflow rate) is 2.4%. No large yard overflows occurred, confirming that this is the upper limit of operable inventory.

In step S6, the proper stock determining unit 106 compares the proper stock calculated in step S4 with the proper stock upper limit value of each destination calculated in step S5, and determines the proper stock that does not violate the proper stock upper limit value. Is determined as an appropriate stock to be held at each transport destination.
The stock management mesh compares the proper stock with the proper stock upper limit value at each destination, and adopts a mesh whose proper stock is equal to or less than the proper stock upper limit value and is closest to the proper stock upper limit value. For example, as shown in Table 6, the proper stock 989.5 of the transfer destination N exceeds the proper stock upper limit 802 of the transfer destination N shown in Table 8. Therefore, the transport destination N determines that the inventory management mesh used to calculate Table 6 cannot be adopted. On the other hand, as shown in Table 7, the appropriate stock 616.6 of the transfer destination N is lower than the appropriate stock upper limit value 802 of the transfer destination N shown in Table 8. Therefore, the destination N determines that the inventory management mesh used for calculating Table 7 can be adopted. As described above, in the comparison between the component case 1 and the component case 2, the mesh based on the component case 2 is determined as the inventory management mesh.

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

  As described above, the appropriate stock is calculated for each of these grouping patterns by using a plurality of grouping patterns in which a plurality of brand grouping methods (combinations of inventory management meshes) are different, and the destination of each destination is calculated. By determining the appropriate stock upper limit value, it is possible to determine the appropriate stock to be held at each transfer destination based on the storage capacity of the transfer destination without excessively consolidating brands. In the past, the relationship between the appropriate stock and the storage capacity upper limit (yard capacity) of the destination was not known, so setting an appropriate stock that greatly exceeded the yard capacity could lead to a large yard waiting vessel. did. By applying the method of the present embodiment, it is possible to calculate an inventory management mesh and an appropriate inventory that do not exceed the appropriate upper limit of the inventory considering the yard capacity. In addition, the inventory management mesh can set an amount that is less than or equal to the upper limit of the appropriate stock, but as close as possible to the upper limit of the appropriate stock, so that brands are not excessively concentrated and operation stability can be secured.

As described above, the present invention has been described with the embodiment. However, the above embodiment is merely an example of the embodiment of the present invention, and the technical scope of the present invention is interpreted in a limited manner. It must not be. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features.
For example, in the above embodiment, the configuration in which the appropriate stock determination support device 100 includes the appropriate stock determination unit 106 has been described, but a configuration in which the appropriate stock determination unit 106 is not provided may be employed. It is possible to assist the user in determining the appropriate stock simply by presenting the calculation results of the appropriate stock calculating unit 104 and the appropriate stock upper limit calculating unit 105 to the user.

An appropriate stock determination support device to which the present invention is applied is realized by a computer device having, for example, a CPU, a ROM, a RAM, and the like. In FIG. 1, the appropriate stock determination support device 100 is illustrated as one device, but may be configured by a plurality of devices, for example.
The present invention can also be realized by supplying software (program) for realizing the functions of the present invention to a system or apparatus via a network or various storage media, and a computer of the system or apparatus reads and executes the program. It is feasible.

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

Claims (11)

An appropriate stock determination support device that assists in determining an appropriate stock to be held at a destination to which a plurality of objects are transferred,
Input means for inputting the transfer result information for each object, and the storage capacity upper limit value of the transfer destination,
Safety stock having not to be out of stock even if the supply and demand fluctuates, and proper stock calculation means for calculating the proper stock using the above-mentioned transport performance information,
A proper stock upper limit value calculating means for calculating a proper stock upper limit value based on the maximum arrival amount per predetermined period calculated using the transfer result information and the capacity upper limit value,
Appropriate stock determining means for comparing the proper stock calculated by the proper stock calculating means with the proper stock upper limit value calculated by the proper stock upper limit calculating means to determine proper stock which does not violate the proper stock upper limit value. A proper stock determination support device characterized by comprising:   2. The apparatus according to claim 1, wherein the appropriate stock calculator calculates an appropriate stock using a stock management mesh obtained by grouping the plurality of objects as a unit of calculation. 3.   3. The proper stock determination according to claim 2, wherein the proper stock calculating means calculates a proper stock for each of the grouping patterns by using a plurality of grouping patterns in which a combination of inventory management meshes is different. Support equipment. The input unit further inputs attribute information for each of the objects, inventory actual information for each of the objects,
4. The appropriate inventory determination support device according to claim 3, further comprising inventory management mesh setting means for setting an inventory management mesh using the attribute information and the actual inventory information.   The inventory management mesh setting means groups the plurality of objects based on the attribute information, and sets an inventory management mesh according to an out-of-stock probability calculated using the inventory actual information. The appropriate stock determination support device according to claim 4.   6. The appropriate stock determination support device according to claim 4, wherein the stock management mesh setting unit performs grouping in order from fine grouping to coarse grouping based on the attribute information. The input means further inputs average usage information for each of the objects,
A safety stock calculation means for calculating a safety stock using the transport result information and the average usage information,
The proper stock calculating means calculates a cycle stock which is a running stock using the received amount included in the transport result information, and calculates a proper stock by adding the safety stock calculated by the safety stock calculating means. The proper stock determination support device according to any one of claims 1 to 6, wherein:   The safety stock calculating means calculates the safety stock days by estimating parameters and calculating the safety stock using the average usage information, assuming that the transfer intervals included in the transfer result information follow the gamma distribution. The appropriate stock determination support device according to claim 7, wherein   The proper stock upper limit value calculating means calculates a maximum arrival amount per the predetermined period by a tweedie distribution, assuming that the conveyance timing included in the conveyance result information follows a Poisson distribution, and the amount of arrival included in the conveyance result information follows a gamma distribution. The proper stock determination support device according to any one of claims 1 to 8, wherein the proper stock upper limit value is calculated from the relationship between the capacity upper limit values. An appropriate stock determination support method for supporting determining an appropriate stock to be held at a destination to which a plurality of objects are transferred,
Input means, inputting the transfer result information for each of the objects, the storage capacity upper limit value of the destination,
Appropriate stock calculation means, a step of calculating a proper stock using the safety stock having not to be out of stock even if the supply and demand fluctuates, and the transport performance information,
An appropriate stock upper limit value calculating unit, based on the maximum arrival amount per a predetermined period calculated using the transfer result information and the capacity upper limit value, calculating an appropriate stock upper limit value;
The proper stock determining means compares the proper stock calculated by the proper stock calculating means with the proper stock upper limit calculated by the proper stock upper limit calculating means, and determines proper stock which does not violate the proper stock upper limit. Determining a proper stock. A program for assisting in determining an appropriate stock to be held at a destination where a plurality of objects are transported,
A process of inputting the transfer result information for each of the objects, and a storage capacity upper limit value of the transfer destination,
A process of calculating a proper stock using the safety stock having not to cause a shortage even if the supply and demand varies, and the transfer result information;
A process of calculating an appropriate stock upper limit value based on the maximum arrival amount per predetermined period calculated using the transfer result information and the capacity upper limit value,
A program for causing a computer to execute a process of comparing the calculated proper stock with the calculated proper stock upper limit value to determine a proper stock that does not violate the proper stock upper limit value.

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