This application claims the benefit of Taiwan application Serial No. 110114402, filed Apr. 21, 2021, the disclosure of which is incorporated by reference herein in its entirety.
The disclosure relates in general to a management method, and applies to an automated inventory management method and a system thereof.
In a modern society, competition in various industries is becoming increasingly fierce, and how to effectively reduce inventory costs has been concerned by everyone. Regarding inventory decisions, most of them use Demand Driven Material Requirements Planning (DDMRP) as the basis for the purchase order, and adjust the purchase order based on historical average sale record, historical sale standard deviation, order delivery time, and demand variation parameters. The demand variation parameters must be manually set, which relies on the experience of the personnel. Therefore, the uncertain factors of order increase in the future, and it is very likely that the inventory costs will increase or out of stock because of few inventory.
The disclosure is directed to an automated inventory management method and a system thereof, which could replace personnel to manually set parameters, and reduce inventory costs and the risk of personnel misjudgment.
According to one embodiment of the disclosure, an automated inventory management method is provided, which includes the following steps. A historical sale state is received, and a future sale of an item is predicted based on the historical sale state to obtain a simulation result of an expected sale state of the item in the next sale cycle. According to the historical sale state of full categories of items and the simulation result of the expected sale state of the item in the next sale cycle, an initial weight of a pre-training model is trained. The initial weight of the pre-training model is used as a weight of an inventory decision module for training, and a purchase order that meets the expected sale state of the item in the next sale cycle is automatically generated. A reward feedback is calculated according to a current sale record and an inventory volume of the item and a purchase order of the item in a previous sale cycle, and the reward feedback and the sale state of the item are input into the inventory decision module to order the item.
According to one embodiment of the disclosure, an automated inventory management system is provided, which includes a historical parameter analysis module, a state analysis module, an initial weight setting module, and an inventory decision module. The historical parameter analysis module is used to receive a historical sale state, and predict a future sale of an item based on the historical sale state, so as to obtain a simulation result of an expected sale state of the item in a next sale cycle. The initial weight setting module is used for training an initial weight of a pre-training model based on the historical sale state of full categories of items and the simulation result of the expected sale state of the item in the next sale cycle. The inventory decision module uses the initial weight of the pre-training model as a weight of the inventory decision module for training, and automatically generates a purchase order that meets the expected sale state of the item in the next sale cycle. The state analysis module calculates a reward feedback based on a current sale record and an inventory volume of the item and a purchase order in a previous sale cycle, and inputs the reward feedback and the sale state of the item into the inventory decision module to order the item.
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments could be implemented in various forms, and should not be construed as being limited to the examples set forth herein; on the contrary, the description of these embodiments makes the present disclosure more comprehensive and complete, and fully conveys the concept of the exemplary embodiments to those skilled in the art. The described features, structures or characteristics could be combined in one or more embodiments in any suitable way.
In addition, the drawings are schematic illustrations of the present disclosure, and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities could be implemented in the form of software, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and/or processor devices and/or microcontroller devices. For example: the historical parameter analysis module, the state analysis module, the initial weight setting module, the pre-training model, the inventory decision module, and the transfer model described therein could be implemented in the form of software to realize these functional entities, or implemented in one or more hardware modules or integrated circuits.
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However, the historical parameter analysis module 110 predicts the future sale record based on the historical sale state 102, the average sale record and its standard deviation of items of same category. When the predicted variation is greater than the safety level (such as the standard deviation of the sale record), it may still happen that the retailer may increase the purchase order and increases the risk cost of full inventory, or the retailer may reduce the purchase order and increases the risk cost of shortage (i.e., out of stock) due to the uncertainty of the simulation prediction. This phenomenon is also called forecast inflation. In order to prevent the above situation, the automated inventory management system 100 of present embodiment calculates a reward feedback 122 based on the current sale record 114, an inventory volume 116 and the purchase order 118 of the item in the previous sale cycle through the state analysis module 120 and the reward feedback is input into a pre-training model 134 to predict the sale record of the next sale cycle, so as to avoid relying on the past experience and self-judgment of the personnel to determine the required sale record.
Especially in the new product launch stage, there is no reliable and clear historical sale state 102 to predict future sale, and there is no enough actual sale as training data to help the neural network 136 perform deep reinforcement learning, so that the weight of each parameter in the neural network 136 that affects the sale record could not be modified and could not improve the accuracy of the sale record prediction. In order to improve the learning efficiency and prediction accuracy of the neural network 136, the automated inventory management system 100 of present embodiment further converts the historical sale state 104 of full categories of items into training data 154 through a transfer model 150, and stores the training data in the training database 152 to increase the data of the pre-trained model 134, and then the initial weight 132 of each parameter of the neural network 136 could be set through the initial weight setting module 130, that is, the initial weight 132 of the pre-trained model 134. The neural network 136 could start training on the basis of a pre-trained model 134. Compared with the conventional neural network that needs to be trained from the beginning, the neural network 136 in present embodiment does not need to adjust weights of the parameters by trial and error. The training time could be saved, and the convergence speed is relatively faster.
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In step S120, the transfer model 150 could train a pre-training model 134 based on the historical sale states 104 of full categories of items and the simulation result 112 of the expected sale state of each item in the next sale cycle. The historical sale states 104 of full categories of the items include each of the historical sale states of items of different types in same attribute. For example, an item to be sold is a certain category of soda, cola, sprite, or juice, while the full categories of items (such as beverages) includes different types of items such as soda, cola, sprite, and juice from the same brand or other brands. That is, the transfer model 150 could convert the historical sale state 102 and the simulation result 112 of each item of different types in same attribute into training data, and store the training data 154 in the training database 152 to increase data of pre-training model 134.
In the embodiment, the historical sale states 104 of different types of beverages such as sodas, cola, and juices of the same brand or other brands are used as the training data for a new product in launch stage to establish an initial weight 132 of a pre-training model 134 and could reduce the prediction error (that is, the reward feedback 122), and could also reduce the probability of full inventory or out of stock, and thus reduce inventory costs.
In step S130, the state analysis module 120 calculates a reward feedback 122 based on the current sale record 114 and inventory volume 116 of the item and the purchase order 118 of the item in the previous sale cycle. Then, in step S140, the reward feedback 122 and the sale state 124 of the item are stored as a training data or a test data in a database 126 and input into a pre-training model 134 for the neural network 136 to perform pre-training and deep reinforcement learning. At the same time, after the training of the neural network 136 is completed, the reward feedback 122 and the sale state 124 of the item could be directly input to the inventory decision module 140 to order the item. After a predetermined period, if necessary, re-evaluation and re-training is required for adjustment. In the embodiment, the training data is used to construct the parameters and neural network 136 that are optimized for the automated inventory management system 100, and the test data could be used as input data for testing the neural network 136 constructed from the training data to ensure that such output of the neural network 136 could meet the expected result.
The above prediction error is, for example, a mean absolute percentage error (MAPE), a mean-square error (MSE), or a mean absolute deviation (MAD), which is used to calculate the ratio of the prediction sale to the actual sale record. The mean absolute percentage error (MAPE) is a percentage of the absolute value of the sum of the current sale record of the item (salet) minus the inventory volume (stockt) and the purchase order (ordert−1) of the item in the previous sale cycle with respect to the current sale record (salet) of the item. The embodiments are mainly divided into the following three situations: (1) when the sum of the inventory volume (stockt) of the item and the purchase order (ordert−1) of the previous sale cycle is greater than or equal to the sum of the expected sale state (salet+1) of the item in the next sale cycle and the standard deviation (stdt) of the current sale record, that is, stockt+ordert−1 salet+1≥stdt, the inventory decision module 140 estimates that the inventory of the item is surplus and needs to be revised downwards for the purchase order 142 of the item in the next sale cycle, to reduce the prediction error; (2) when the sum of the inventory volume (stockt) of the item and the purchase order (ordert−1) of the previous sale cycle is greater than or equal to the expected sale state (salet+1) of the item in the next sale cycle, and less than the sum of the expected sale state (salet+1) of the item in the next sale cycle and the standard deviation (stdt) of the current sale record, that is, salet+1+stdt≥stockt+ordert−1≥salet+1, the inventory decision module 140 estimates that the inventory of the item meets the expected sale state, and there is no need to adjust the purchase order 142 of the item in the next sale cycle; (3) when the expected sale state salet+1 of the item in the next sale cycle is greater than the sum of the inventory volume (stockt) of the item and the purchase order (ordert−1) of the previous sale cycle, that is, salet+1>stockt+ordert−1, the inventory decision module 140 estimates that the inventory of the item is not enough for the expected sale record, and needs to be revised upwards for the purchase order 142 of a next sale cycle to reduce the prediction error.
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Since the automated inventory management system 100 of the embodiment could calculate a reward feedback 122 based on the current sale record 114 and inventory volume 116 of the item and the purchase order 118 of the previous sale cycle through the state analysis module 120, and the reward feedback 122 is input into the pre-trained neural network 136 to predict the sale record of the next sale cycle, so as to avoid relying on the past experience and self-judgment of the personnel to determine the required sale record. The prediction error (i.e., the reward feedback 122) could be reduced, and the probability of full inventory or shortage (i.e., out of stock) could also be reduced, and thus inventory costs are reduced.
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The following embodiment uses the weekly sale record and historical sale state of items as the test data of the pre-trained neural network 136 for description. Assuming that the current time point t is 2021/1/4 (Monday), the time point t−1 is last week, 2020/12/28 (Monday), and the time point t+1 is next week 2021/1/11 (Monday). at the time point t, the inventory volume (stock0104=100), sale record (sale0104=120), purchase order at the time point t−1 (order1228=150), historical sale average of 13 weeks (mean0104=200). The standard deviation of the historical sale record of 13 weeks (std0104=50), where the expected sale record is expressed as the predicted value at the time point t.
First, the sale state (sale0104) of the item is input into the pre-trained neural network 136. The sale state (sale0104) of the item includes the historical sale records from 1 to 52 weeks, and a historical sale average of 13 weeks (mean0104=200), a standard deviation of historical sale record of 13 weeks (std0104=50), expected sale record () and expected sale record at the time point t−1 (), then the pre-trained neural network 136 could output the decision weight (Action0104=0.5), and the inventory decision module 140 calculates the purchase order at the time point t (order0104=mean0104×Action0104=200×0.5=100), output purchase order (order0104=100).
Next, the state analysis module 120 receives the purchase order at time t (order0104=100), the actual sale record at time t (sale0104=120), and the purchase order at time t−1 (order1228=150), and outputs the inventory volume at time t+1 (stock0111=stock0104−sale0104+order1228=100−120+150=130).
At the same time, the state analysis module 120 determines that stock0104, order1228, sale0104, and std0104 belong to the first case (1), because stock0104+order1228≥sale0104+std0104, therefore,
is obtained. Assuming that the parameter over_penalty=−1, the reward feedback (Reward0104=MAPE0104×over_penalty=1.0833×−1=−1.0833) is output, which means that the inventory of the item is excessive, and the purchase order (order0111) of the item in the next sale cycle needs to be corrected downwards to reduce prediction error.
In another embodiment, if the state analysis module 120 determines that stock0104, order1228, sale0104, and std0104 belong to the third case (3), that is, sale0104>stock0104+order1228, assuming that the parameter under_penalty=−1, the reward feedback (Reward0104=MAPE0104×under_penalty=1.0833×−1=−1.0833) is output, which means that the inventory of the item is Insufficient and the purchase order (order0111) of the next sale cycle needs to be corrected upwards to reduce the prediction error.
Then, at the next time point t+1, the sale state (state0111) of the item is input to the pre-trained neural network 136, and the decision weight (Action0111) is output from the neural network 136, and the inventory decision module 140 calculates the purchase order at the time point t+1 (order0111=mean0111×Action0111), and so on. In this way, the system could automatically generate a purchase order that meets the expected sale record of the item in the next sale cycle.
The aforementioned pre-training model 134 is, for example, a deep neural networks (DNN) model, a convolutional neural network (CNN) model, or a support vector machine (SVM) model for performing machine learning and training. Convolutional neural network models could be divided into regional convolutional neural networks (R-CNN), fast regional convolutional neural networks (Fast R-CNN) and faster regional convolutional neural networks (Faster R-CNN)), etc., by dividing the input information into multiple regions, and dividing each region into the corresponding category, and then combining all the regions together to complete the sale record prediction.
Referring to Table 1, which shows that the prediction results obtained by deep reinforcement learning and pre-training of the neural network 136 in the embodiment are compared with the traditional model based on the historical average sale record of 13 weeks or the sale record prediction of the neural network. It could be seen from Table 1 that the automated inventory management system 100 of the embodiment could reduce the prediction error, in which the mean absolute percentage error (10.54% or lower), the out-of-stock rate (1.48% or lower), and the full inventory rate (3.83% or lower) are better than the prediction results of the traditional model, and then the suitable parameters and neural network 136 are constructed accordingly.
It could be seen that the automated inventory management method and system of the foregoing embodiments of the disclosure could improve the accuracy of prediction for sale, and reduce inventory costs and the risk of misjudgment by personnel.
It will be apparent to those skilled in the art that various modifications and variations could be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
Number | Date | Country | Kind |
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110114402 | Apr 2021 | TW | national |