Patent Publication Number: US-2023162263-A1

Title: Shoe purchase recommendation device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2021-190748 filed in Japan on Nov. 25, 2021. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a shoe purchase recommendation device that predicts a change in a foot size of a prediction target person and recommends purchase of shoes. 
     2. Description of the Related Art 
     It is desired to wear shoes having an appropriate volume suited to the foot size of a wearer, such as a foot length, a foot circumference, and an arch height, and wearing shoes having an inappropriate volume may cause hallux valgus or may cause a shoe blister. In particular, when the wearer is a child, wearing shoes having an inappropriate volume sometimes adversely affect the growth of the foot. 
     Since the foot size changes with growth and aging, even a shoe having an optimum volume for the current foot size will not have an optimum volume for the foot size in the future in some cases. 
     WO 2021/130889 A discloses an invention that predicts a change in a foot length and notifies a customer of a replacement purchase of shoes. 
     In general, when deciding whether or not to purchase shoes, not only the own foot size of the user but also information such as whether the foot size of the user is larger or smaller than the foot size of another person may serve as one of the decision materials. However, the invention disclosed in WO 2021/130889 A has not been sufficient to visually provide a shoe purchase-recommended date and a criterions to decide as to whether or not to make a purchase. 
     The present invention has been made in view of the above, and an object of the present invention is to obtain a shoe purchase recommendation device capable of allowing a user to utilize information on a foot size of another person as a criterion to decide as to whether or not to purchase shoes. 
     SUMMARY OF THE INVENTION 
     In order to solve the above-described problem and achieve the object, a shoe purchase recommendation device according to the present invention includes a user data storage unit that stores user data including at least an age and a foot size measurement value of a user; a foot size change prediction unit that calculates a change prediction value of a foot size of the user on a basis of the user data; a product information storage unit that stores product information including a shoe size; a purchase recommendation processing unit that determines a purchase-recommended date and a purchase-recommended product of shoes on a basis of the change prediction value and the product information; and a screen display processing unit that performs processing of displaying, on a display unit, a foot size change diagram based on the foot size measurement value or the change prediction value from a past time point to present and the change prediction value in a period from the present to a future time point, and a comparison value diagram indicating a comparison value of the foot size from the past time point to the future time point. The screen display processing unit displays the purchase-recommended date and the purchase-recommended product on the display unit together with the foot size change diagram and the comparison value diagram. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a first embodiment of the present invention; 
         FIG.  2    is a diagram illustrating an example of a notification screen displayed on a display input device by a screen display processing unit of the shoe purchase recommendation device according to the first embodiment; 
         FIG.  3    is a flowchart illustrating a flow of action of the shoe purchase recommendation device according to the first embodiment; 
         FIG.  4    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a second embodiment of the present invention; 
         FIG.  5    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the second embodiment to determine a purchase-recommended product; 
         FIG.  6    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a third embodiment of the present invention; 
         FIG.  7    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the third embodiment to determine a purchase-recommended product; 
         FIG.  8    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a fourth embodiment of the present invention; 
         FIG.  9    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the fourth embodiment to determine a purchase-recommended product; 
         FIG.  10    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a fifth embodiment of the present invention; 
         FIG.  11    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the fifth embodiment to determine a purchase-recommended product; 
         FIG.  12    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a sixth embodiment of the present invention; 
         FIG.  13    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a seventh embodiment of the present invention; and 
         FIG.  14    is a diagram illustrating a hardware configuration example of the shoe purchase recommendation devices according to the first to seventh embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of a shoe purchase recommendation device according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by these embodiments. In addition, in the embodiments to be described below, the same or common parts are denoted by the same reference signs, and the description thereof will not be repeated. 
     In the following description, a case where the foot size is the foot length will be taken as an example. However, the foot size only has to be dimensions of a measurable portion, such as a foot circumference and an arch height, and is not limited to dimensions of a specific portion. In addition, the foot size may be a combination of dimensions of different portions of the foot, such as the foot length, the foot circumference, and the arch height, or may be three-dimensional scan data of the user&#39;s foot. Furthermore, not only the whole size of the foot but also the dimensions of a part of the shoe corresponding to the foot length, the foot circumference, the arch height, or the like may be regarded as the foot size. 
     First Embodiment 
       FIG.  1    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a first embodiment of the present invention. A shoe purchase recommendation device  10 A includes: a user data storage unit  11  that stores user data  111  including at least an age  111 A, a foot size measurement value  111 B, and a foot size measurement date  111 C of a user; a foot size change prediction unit  12  that calculates a change prediction value of a foot size of the user on the basis of the user data  111 ; a product information storage unit  13  that stores product information  131  including a shoe size  131 A and a product image  131 B; a purchase recommendation processing unit  14  that determines a purchase-recommended date and a purchase-recommended product of shoes on the basis of the change prediction value and the product information  131 ; a comparison value storage unit  15  that stores a comparison value  151  for foot size comparison; and a screen display processing unit  16  that performs processing of displaying a foot size change diagram based on the foot size measurement value  111 B or the change prediction value from a past time point to the present and the change prediction value in a period from the present to a future time point, and a comparison value diagram indicating the comparison value  151  of the foot size from the past time point to the future time point. The foot size measurement value  111 B is a measurement value of the foot size of the user measured in the past. The foot size measurement date  111 C is a date on which the foot size was measured in the past. As the comparison value  151 , an average value of the foot sizes of the user at the age  111 A can be used. However, as the comparison value  151 , not only the average value but also data of the foot size when the user&#39;s parent or older brother was the same age as the user can be used. When the average value of the foot sizes is used as the comparison value  151 , an average value of members who use the shoe purchase recommendation device  10 A may be used, or a statistical average value including persons who do not use the shoe purchase recommendation device  10 A may be used. The age  111 A is data representing elapsed time from birth. The age  111 A may be in “month old” representing the elapsed time from birth in units of months, instead of units of years. 
     The foot size change prediction unit  12  holds a foot size change table  121 , which is statistical data of changes in the foot size, and calculates a change prediction value of the foot size by adding an average change amount of the foot size based on the age  111 A to the foot size measurement value  111 B. The foot size change prediction unit  12  can calculate not only the prediction value of the foot size at a future time point dependent on the current foot size measurement value  111 B as a basis, but also the prediction value of the foot size at a past time point dependent on the past foot size measurement value  111 B as a basis. Note that the foot size change prediction unit  12  may calculate the change prediction value of the foot size by adding the change amount of the foot size based on data of the foot size of an older family member of the user included in the user data  111  stored in the user data storage unit  11 , to the foot size measurement value  111 B. 
     In addition to the age  111 A, the foot size measurement value  111 B, and the foot size measurement date  111 C, the user data  111  may include the height, weight, gender, residential region, current foot size data of the family member, and past foot size data of the family member. The foot size change prediction unit  12  calculates the change prediction value of the foot size using these pieces of information, whereby the change prediction value can be calculated by more accurately predicting the change in the foot size. In the shoe purchase recommendation device  10 A according to the first embodiment, the user data  111  includes a height  111 G and a weight  111 H of the user. Therefore, by calculating the change prediction value of the foot size using the age  111 A, the height  111 G, and the weight  111 H of the user and the foot size measurement value  111 B at the time point of the input age, the foot size change prediction unit  12  can calculate the foot size prediction value in consideration of the physique of the user. 
     A display input device  20  including a display unit  21  and an input unit  22  is connected to the shoe purchase recommendation device  10 A. A liquid crystal display or an organic electroluminescence display can be applied as the display unit  21 , but a display device other than these displays may be adopted. Input devices such as a keyboard and a pointing device can be applied as the input unit  22 , but an input device other than these input devices may be adopted. Note that a touch screen monitor having both of a display function and an input function together can also be applied as the display unit  21  and the input unit  22 . The display input device  20  is connected to the shoe purchase recommendation device  10 A via the Internet. Note that the display input device  20  may be directly connected to the shoe purchase recommendation device  10 A not via the Internet. In addition, the shoe purchase recommendation device  10 A may include the display unit  21  and the input unit  22 . In this case, the display input device  20  does not have to be connected to the shoe purchase recommendation device  10 A. 
     A foot size measuring device  30  is connected to the shoe purchase recommendation device  10 A. The foot size measuring device  30  outputs the foot size measurement value  111 B and the foot size measurement date  111 C obtained by measuring the foot size of the user. The foot size measurement value  111 B and the foot size measurement date  111 C are accumulated in the user data storage unit  11 . Note that the shoe purchase recommendation device  10 A may be provided with a user interface for input such that the foot size measurement value  111 B and the foot size measurement date  111 C are input by operating the user interface. In addition, the shoe purchase recommendation device  10 A may acquire the foot size measurement value  111 B and the foot size measurement date  111 C by communicating with another device that stores the foot size measurement value  111 B and the foot size measurement date  111 C. Furthermore, the foot size measurement date  111 C does not have to be data separated from the foot size measurement value  111 B and may be data of creation date and time or update date and time included in the file property of the foot size measurement value  111 B. 
     To give an example, a server of a shoe manufacturer can be applied as the shoe purchase recommendation device  10 A. In addition, a smartphone terminal of the user can be applied as the display input device  20 . Furthermore, a three-dimensional foot last automatic measuring instrument or an information terminal such as a smartphone terminal and a tablet terminal of the user can be applied as the foot size measuring device  30 . 
     The shoes are set with a foot size fitting range for each size. To give an example, for a certain shoe having a size of 20 cm, a foot length of 19.15 cm to 19.56 cm is set as the foot size fitting range. Accordingly, the day on which the foot length of the user reaches 19.15 cm is the purchase-recommended date on which the purchase of the shoes having a size of 20 cm is recommended. In this manner, the purchase recommendation processing unit  14  determines the day on which the change prediction value of the foot size of the user reaches the foot size fitting range of shoes that are the purchase-recommended product, as the purchase-recommended date. 
     The screen display processing unit  16  sets the day on which a preset period elapses from the previous foot size measurement date  111 C, as the measurement-recommended date. 
       FIG.  2    is a diagram illustrating an example of a notification screen displayed on the display input device by the screen display processing unit of the shoe purchase recommendation device according to the first embodiment. A notification screen  200  contains a foot size change diagram  201 , a comparison value diagram  202 , and a purchase recommendation balloon  203 . A purchase-recommended date  203 A and a purchase-recommended product image  203 B are displayed inside the purchase recommendation balloon  203 . The processing of displaying the notification screen  200  containing the foot size change diagram  201  and the comparison value diagram  202  on the display unit  21  is performed by the screen display processing unit  16 . 
     The shoe purchase recommendation device  10 A according to the first embodiment represents the foot size change diagram  201  and the comparison value diagram  202  as line graphs including plots and lines connecting the plots on a plane with the magnitude of the foot size as a vertical axis and the time as a horizontal axis, but may display the foot size change diagram  201  and the comparison value diagram  202  by another method. 
     In the foot size change diagram  201 , the foot size measurement value  111 B is represented by a black circle plot, and the foot size change prediction value is represented by a white triangle plot. In addition, the past scheduled measurement date on which the foot size was not measured is plotted by replacing the foot size measurement value  111 B on that scheduled measurement date with the foot size change prediction value. Accordingly, the user is allowed to know the scheduled measurement date when the foot size was not measured, by visually recognizing the foot size change diagram  201 . In addition, among the lines connecting the plots, the lines connecting the past foot size measurement values  111 B or the foot size change prediction values are represented by solid lines, and the lines connecting the future foot size change prediction values are represented by broken lines. Note that it is sufficient that the prediction value and the measurement value can be distinguished from each other, and the line types are not limited to the exemplified line types. 
       FIG.  3    is a flowchart illustrating a flow of action of the shoe purchase recommendation device according to the first embodiment. In step S 11 , the foot size change prediction unit  12  calculates the change prediction value of the foot size of the user on the basis of the user data  111  stored in the user data storage unit  11 . In step S 12 , the screen display processing unit  16  creates the foot size change diagram  201 . In step S 13 , the screen display processing unit  16  reads the comparison value  151  from the comparison value storage unit  15  and creates the comparison value diagram  202 . In step S 14 , the purchase recommendation processing unit  14  determines the purchase-recommended date and the purchase-recommended product of shoes on the basis of the change prediction value calculated by the foot size change prediction unit  12  and the product information  131  stored in the product information storage unit  13 . 
     In step S 15 , the screen display processing unit  16  reads the product image  131 B of the purchase-recommended product from the product information storage unit  13  and creates the purchase recommendation balloon  203 . In step S 16 , the screen display processing unit  16  performs processing of displaying the notification screen  200 . 
     By displaying the purchase recommendation balloon  203  containing the purchase-recommended date  203 A and the purchase-recommended product image  203 B on the notification screen  200 , the shoe purchase recommendation device  10 A according to the first embodiment can urge the purchase of shoes at an appropriate timing when the foot size of the user rises to the foot size fitting range of the shoes. In addition, since the shoe purchase recommendation device  10 A displays the purchase recommendation balloon  203  with the foot size change diagram  201  and the comparison value diagram  202  on the notification screen  200 , the user is allowed to decide whether or not to purchase shoes, by utilizing information on the foot size based on the statistical data or the data of the foot size of the parent or brother, as a criterion to decide. 
     Second Embodiment 
       FIG.  4    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a second embodiment of the present invention. A shoe purchase recommendation device  10 B according to the second embodiment is different from the shoe purchase recommendation device  10 A according to the first embodiment in that a designated genre  111 D, which is a sports genre designated by a user, is included in user data  111 , and an application genre  131 C, which is a sports genre in which the shoes are used, is included in product information  131 . 
     When there are shoes of which the application genre  131 C matches the designated genre  111 D among candidates for the purchase-recommended product selected on the basis of the change prediction value of the foot size, a purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of which the application genre  131 C matches the designated genre  111 D. 
       FIG.  5    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the second embodiment to determine the purchase-recommended product. In step S 21 , the purchase recommendation processing unit  14  selects candidates for the shoes recommended to purchase on the basis of the change prediction value of the foot size. In step S 22 , the purchase recommendation processing unit  14  verifies whether or not there are shoes of which the application genre  131 C matches the designated genre  111 D among the selected candidates. When there are shoes of which the application genre  131 C matches the designated genre  111 D, Yes is taken in step S 22 , and the processing proceeds to step S 23 . When there are no shoes of which the application genre  131 C matches the designated genre  111 D, No is taken in step S 22 , and the processing proceeds to step S 24 . 
     In step S 23 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the candidates selected in step S 21 , by prioritizing the shoes of which the application genre  131 C matches the designated genre  111 D. 
     In step S 24 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the candidates selected in step S 21 , by prioritizing shoes having a high degree of fitting in the foot size. Note that it is assumed that the shoes of which a median value of the foot size fitting range is closer to the foot size prediction value has a higher degree of fitting in the foot size. 
     The shoe purchase recommendation device  10 B according to the second embodiment can determine the purchase-recommended product by prioritizing shoes suitable for the genre designated in advance by the user, from among the shoes fitting to the change prediction value of the foot size of the user, and thus can recommend the purchase of the shoes suited to the preference of the user. 
     Note that approximate genres may be set in advance for sports genres that can be designated as the designated genre  111 D such that, when there are no shoes of which the application genre  131 C matches the designated genre  111 D, a product to be purchased is determined by prioritizing the shoes for the approximate genre. For example, competition groups such as an indoor court category including basketball, volleyball, and badminton, an outdoor limited contact category including soccer, rugby, and baseball, and an outdoor non-contact category including tennis, lacrosse, and track and field events may be set such that, when there are no shoes of which the application genre  131 C matches the designated genre  111 D among the candidates for the purchase-recommended product, the purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes for a competition belonging to the competition group including the designated genre  111 D. Note that the case where “there are no shoes of which the application genre matches the designated genre” includes both of a case where the commodity itself does not exist and a case where the commodity exists but there is no stock. 
     Third Embodiment 
       FIG.  6    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a third embodiment of the present invention. A shoe purchase recommendation device  10 C according to the third embodiment is different from the shoe purchase recommendation device  10 A according to the first embodiment in that a designated color  111 E, which is a color designated by a user, is included in user data  111 , and a shoe color  131 D, which is information on the color of the shoes, is included in product information  131 . The shoe color  131 D is not limited to the color of a region occupying a large proportion on the outer surface of the shoe and may be a color of a logo mark provided on the outer surface of the shoe, or may be a color of a conspicuous part although occupying a small proportion on the outer surface of the shoe. 
     When there are shoes of which the shoe color  131 D matches the designated color  111 E among the candidates for the purchase-recommended product selected on the basis of the change prediction value of the foot size, a purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of which the shoe color  131 D matches the designated color  111 E. 
       FIG.  7    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the third embodiment to determine the purchase-recommended product. In step S 31 , the purchase recommendation processing unit  14  selects candidates for the shoes recommended to purchase on the basis of the change prediction value of the foot size. In step S 32 , the purchase recommendation processing unit  14  verifies whether or not there are shoes of which the shoe color  131 D matches the designated color  111 E among the selected candidates. When there are shoes of which the shoe color  131 D matches the designated color  111 E, Yes is taken in step S 32 , and the processing proceeds to step S 33 . When there are no shoes of which the shoe color  131 D matches the designated color  111 E, No is taken in step S 32 , and the processing proceeds to step S 34 . 
     In step S 33 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the candidates selected in step S 31 , by prioritizing the shoes of which the shoe color  131 D matches the designated color  111 E. 
     In step S 34 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the candidates selected in step S 31 , by prioritizing shoes having a high degree of fitting in the foot size. Note that it is assumed that the shoes of which a median value of the foot size fitting range is closer to the foot size prediction value has a higher degree of fitting in the foot size. 
     The shoe purchase recommendation device  10 C according to the third embodiment can determine the purchase-recommended product by prioritizing the shoes of the color designated in advance by the user, from among the shoes fitting to the change prediction value of the foot size of the user, and thus can recommend the purchase of the shoes suited to the preference of the user. 
     Note that approximate colors may be set in advance for colors that can be designated as the designated color  111 E such that, when there are no shoes of which the shoe color  131 D matches the designated color  111 E, a product to be purchased is determined by prioritizing the shoes of the approximate color. For example, color groups such as a monotone category including black, white, and gray, a warm color category including red, pink, and brown, a cool color category including blue, purple, and green, and a light color category including orange, yellow, and gold may be set in advance such that, when there are no shoes of which the shoe color  131 D matches the designated color  111 E among the candidates for the purchase-recommended product, the purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of a color belonging to the color group including the designated color  111 E. Note that the case where “there are no shoes of which the shoe color matches the designated color” includes both of a case where the commodity itself does not exist and a case where the commodity exists but there is no stock. 
     Fourth Embodiment 
       FIG.  8    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a fourth embodiment of the present invention. A shoe purchase recommendation device  10 D according to the fourth embodiment is different from the shoe purchase recommendation device  10 A according to the first embodiment in that a designated genre  111 D, which is a sports genre designated by a user, and a designated color  111 E, which is a color designated by the user, are included in user data  111 , and an application genre  131 C, which is a sports genre in which the shoes are used, and a shoe color  131 D, which is information on the color of the shoes, are included in product information  131 . 
     A purchase recommendation processing unit  14  selects a purchase-recommended candidate collection of which the application genre  131 C matches the designated genre  111 D from among candidates for the purchase-recommended product selected on the basis of the change prediction value of the foot size, and determines the purchase-recommended product by prioritizing the shoes of which the shoe color  131 D matches the designated color  111 E from the purchase-recommended candidate collection. 
       FIG.  9    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the fourth embodiment to determine the purchase-recommended product. In step S 41 , the purchase recommendation processing unit  14  selects candidates for the shoes recommended to purchase on the basis of the change prediction value of the foot size. In step S 42 , the purchase recommendation processing unit  14  verifies whether or not there are shoes of which the application genre  131 C matches the designated genre  111 D among the selected candidates. When there are shoes of which the application genre  131 C matches the designated genre  111 D, Yes is taken in step S 42 , and the processing proceeds to step S 43 . When there are no shoes of which the application genre  131 C matches the designated genre  111 D, No is taken in step S 42 , and the processing proceeds to step S 44 . 
     In step S 43 , the purchase recommendation processing unit  14  selects the purchase-recommended candidate collection from among the shoes of which the application genre  131 C matches the designated genre  111 D among the candidates selected in step S 41 . 
     In step S 44 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the candidates selected in step S 41 , by prioritizing shoes having a high degree of fitting in the foot size. Note that it is assumed that the shoes of which a median value of the foot size fitting range is closer to the foot size prediction value has a higher degree of fitting in the foot size. After step S 44 , the processing ends. 
     In step S 45 , the purchase recommendation processing unit  14  verifies whether or not there are shoes of which the shoe color  131 D matches the designated color  111 E in the purchase-recommended candidate collection. When there are shoes of which the shoe color  131 D matches the designated color  111 E, Yes is taken in step S 45 , and the processing proceeds to step S 46 . When there are no shoes of which the shoe color  131 D matches the designated color  111 E, No is taken in step S 45 , and the processing proceeds to step S 47 . 
     In step S 46 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the shoes of which the shoe color  131 D matches the designated color  111 E in the purchase-recommended candidate collection selected in step S 43 . 
     In step S 47 , the purchase recommendation processing unit  14  randomly determines the purchase-recommended product from the purchase-recommended candidate collection. 
     The shoe purchase recommendation device  10 D according to the fourth embodiment determines the shoes of which the shoe color  131 D matches the designated color  111 E from the purchase-recommended candidate collection, of which the application genre  131 C matches the designated genre  111 D, as the purchase-recommended product, and thus can recommend the purchase of the shoes that meet the conditions designated by the user. 
     Fifth Embodiment 
       FIG.  10    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a fifth embodiment of the present invention. A shoe purchase recommendation device  10 E according to the fifth embodiment is different from the shoe purchase recommendation device  10 A according to the first embodiment in that a sporting ability measurement value  111 F, which is a measurement result for the sporting ability of a user, is included in user data  111 , and a desired sporting ability value  131 E, which is information on the sporting ability coupled with the shoes, is included in product information  131 . 
     Examples of the sporting ability include, but are not limited to, the time of short-distance running, the time of long-distance running, the height of vertical jump, and the number of times of repeated side stepping. The desired sporting ability value  131 E indicates the sporting ability desired to draw out the original potential of the shoes, and when the sporting ability measurement value  111 F of the wearer of the shoes is equal to or less than the desired sporting ability value  131 E, the original potential of the shoes will not be allowed to be drawn out. 
     When there are shoes of which the desired sporting ability value  131 E is equal to or less than the sporting ability measurement value  111 F among the candidates for the purchase-recommended product selected on the basis of the change prediction value of the foot size, a purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of which the desired sporting ability value  131 E is equal to or less than the sporting ability measurement value  111 F. 
       FIG.  11    is a flowchart illustrating a flow of processing of the shoe purchase recommendation device according to the fifth embodiment to determine the purchase-recommended product. In step S 51 , the purchase recommendation processing unit  14  selects candidates for the shoes recommended to purchase on the basis of the change prediction value of the foot size. In step S 52 , the purchase recommendation processing unit  14  verifies whether or not there are shoes of which the desired sporting ability value  131 E is equal to or less than the sporting ability measurement value  111 F among the selected candidates. When there are shoes of which the desired sporting ability value  131 E is equal to or less than the sporting ability measurement value  111 F, Yes is taken in step S 52 , and the processing proceeds to step S 53 . When there are no shoes of which the desired sporting ability value  131 E is equal to or less than the sporting ability measurement value  111 F, No is taken in step S 52 , and the processing proceeds to step S 54 . 
     In step S 53 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the candidates selected in step S 51 , by prioritizing the shoes of which the desired sporting ability value  131 E is equal to or less than the sporting ability measurement value  111 F. 
     In step S 54 , the purchase recommendation processing unit  14  determines the purchase-recommended product from among the candidates selected in step S 51 , by prioritizing shoes having a high degree of fitting in the foot size. Note that it is assumed that the shoes of which a median value of the foot size fitting range is closer to the foot size prediction value has a higher degree of fitting in the foot size. 
     In particular, in sports shoes, a plurality of models is sometimes provided by performance of the wearer. In general, a model for beginners has specifications that give more importance on ease of handling than potential, whereas a model for advanced-level persons has specifications that give more importance on potential than ease of handling. Accordingly, if a person with low sporting ability wears a model for advanced-level persons, the original potential of the shoes will not be allowed to be sufficiently drawn out, and as a result, the wearer will not be able to sufficiently exhibit the own performance of the wearer. In addition, if a person with high sporting ability wears a model for beginners, the wearer will not be able to sufficiently exhibit the own performance of the wearer because the wearer is restricted by the potential of the shoes. By determining shoes recommended to purchase on the basis of the sporting ability of the user, the shoe purchase recommendation device  10 E according to the fifth embodiment can recommend the purchase of the shoes that allow the user to easily exhibit performance. 
     Sixth Embodiment 
       FIG.  12    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a sixth embodiment of the present invention. A shoe purchase recommendation device  10 F according to the sixth embodiment is different from the shoe purchase recommendation device  10 A according to the first embodiment in including a purchase recommendation interval determination unit  17  that determines a purchase recommendation interval on the basis of an age  111 A of the user. 
     When the purchase-recommended date based on the change prediction value and product information  131  has not been set until the purchase recommendation interval has elapsed from the previous purchase-recommended date, a purchase recommendation processing unit  14  sets the day on which the purchase recommendation interval elapses, as the purchase-recommended date. 
     Since, for example, the sole of the shoe is worn out as the shoe is used, it is preferable even for a user at an age with little change in the foot size to periodically purchase shoes for replacement. Even when the purchase-recommended date based on the change prediction value and the product information  131  has not been set until the purchase recommendation interval determined on the basis of the age  111 A of the user has elapsed from the previous purchase-recommended date, the shoe purchase recommendation device  10 F according to the sixth embodiment sets the day on which the purchase recommendation interval elapses, as the purchase-recommended date, and thus can recommend the purchase of shoes at an appropriate timing even for the user at an age with little change in the foot size. Meanwhile, when a child whose foot size changes in a short period of time, particularly a child in a growth period, is the user, the purchase of shoes at an appropriate timing can be recommended because the purchase-recommended date is set on the basis of the change prediction value of the foot size and the product information  131 . 
     Seventh Embodiment 
       FIG.  13    is a diagram illustrating a configuration of a shoe purchase recommendation device according to a seventh embodiment of the present invention. A shoe purchase recommendation device  10 G according to the seventh embodiment is different from the shoe purchase recommendation device  10 A according to the first embodiment in that stock information  131 F indicating whether or not the shoes are in stock is included in product information  131 . 
     In the shoe purchase recommendation device  10 G according to the seventh embodiment, after selecting candidates for the purchase-recommended product on the basis of the foot size change prediction value and the product information  131 , a purchase recommendation processing unit  14  confirms the presence or absence of stock on the basis of the stock information  131 F and determines the purchase-recommended product from among the shoes in stock. 
     Since the purchase-recommended product is determined from among the shoes in stock, the shoe purchase recommendation device  10 G according to the seventh embodiment can avoid the occurrence of a situation in which the shoes recommended to purchase are out of stock and the user is not allowed to purchase the shoes recommended to purchase. 
     The shoe purchase recommendation devices  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G according to each of the above embodiments are preferred when a child whose foot size changes in a short period of time is a user, but can also recommend an adult user to purchase shoes at an appropriate timing. 
     Next, a hardware configuration of the shoe purchase recommendation devices  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G according to each of the above embodiments will be described.  FIG.  14    is a diagram illustrating a hardware configuration example of the shoe purchase recommendation devices according to the first to seventh embodiments.  FIG.  14    illustrates a hardware configuration in a case where the functions of the shoe purchase recommendation devices  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G are implemented by using hardware that executes a program. 
     The shoe purchase recommendation devices  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G include a processor  81  that executes various sorts of processing, a memory  82  that is a built-in memory, and a storage device  83  that stores information. The processor  81  reads the program stored in the storage device  83  into the memory  82  and executes the read program. The user data storage unit  11  and the product information storage unit  13  are implemented by the storage device  83 . 
     As described above, the shoe purchase recommendation devices  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G according to the present invention include: the user data storage unit  11  that stores the user data  111  including at least the age  111 A and the foot size measurement value  111 B of a user; the foot size change prediction unit  12  that calculates the change prediction value of the foot size of the user on the basis of the user data  111 ; the product information storage unit  13  that stores the product information  131  including the shoe size  131 A; the purchase recommendation processing unit  14  that determines the purchase-recommended date and the purchase-recommended product of shoes on the basis of the change prediction value and the product information  131 ; and the screen display processing unit  16  that performs processing of displaying, on the display unit  21 , the foot size change diagram  201  based on the foot size measurement value or the change prediction value from a past time point to the present and the change prediction value in a period from the present to a future time point, and the comparison value diagram  202  indicating the comparison value of the foot size from the past time point to the future time point, in which the screen display processing unit  16  displays the purchase-recommended date and the purchase-recommended product on the display unit  21  together with the foot size change diagram  201  and the comparison value diagram  202 . Accordingly, the user of the shoe purchase recommendation devices  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G according to the present invention can utilize information on the foot size of another person as a decision material as to whether or not the user purchases shoes. 
     In addition, the screen display processing unit  16  represents the foot size change diagram  201  and the comparison value diagram  202  as plots on a plane with the magnitude of the foot size as a vertical axis and the time as a horizontal axis, whereby the measurement values and the prediction values of the own foot size of the user can be directly compared with the comparison values in time series. 
     The screen display processing unit  16  represents the foot size measurement value and the change prediction value in the foot size change diagram  201  as different types of plots, whereby the user is allowed to directly distinguish between whether the foot size at a certain time point is an actual measurement value actually measured or a prediction value calculated on the basis of growth prediction. 
     In addition, the purchase recommendation interval determination unit  17  that determines the purchase recommendation interval on the basis of the age of the user is included, and when the purchase-recommended date based on the change prediction value and the product information has not been set until the purchase recommendation interval has elapsed from the previous purchase-recommended date, the purchase recommendation processing unit  14  sets the day on which the purchase recommendation interval elapses, as the purchase-recommended date, whereby the purchase of shoes can be recommended at an appropriate timing even for the user at an age with a small change in the foot size. 
     In addition, when the foot size was not measured on the measurement-recommended date set at a predetermined interval, on which the measurement of the foot size is recommended, the screen display processing unit  16  creates the foot size change diagram  201  by replacing the foot size measurement value on the measurement-recommended date on which the foot size was not measured, with the change prediction value, whereby the foot size change diagram  201  having a small difference from a case where the measurement is performed can be created even when the user did not measure the foot size. 
     In addition, the designated color  111 E designated by the user is included in the user data  111 , the shoe color  131 D is included in the product information  131 , and the purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of the shoe color  131 D matching the designated color  111 E, from among the shoes fitting to the change prediction value, whereby the purchase of the shoes of the color suited to the taste of the user can be recommended at an appropriate timing. 
     In addition, the designated genre  111 D, which is a sports genre designated by the user, is included the user data  111 , the application genre  131 C, which is a sports genre in which the shoes are used, is included the product information  131 , and the purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of which the application genre  131 C matches the designated genre  111 D, from among the shoes fitting to the change prediction value, whereby the purchase of the shoes for use in the sports genre designated by the user can be recommended at an appropriate timing. 
     In addition, the designated genre  111 D, which is a sports genre designated by the user, and the designated color  111 E designated by the user are included the user data  111 , the application genre  131 C, which is a sport genre in which the shoes are used, and the shoe color  131 D are included in the product information, and the purchase recommendation processing unit  14  selects the purchase-recommended candidate collection by prioritizing the shoes of which the application genre  131 C matches the designated genre  111 D, from among the shoes fitting to the change prediction value, and determines the purchase-recommended product by prioritizing the shoes of the shoe color  131 D matching the designated color  111 E from the purchase-recommended candidate collection, whereby the purchase of the shoes for the sports genre designated by the user and of the color suited to the taste of the user can be recommended at an appropriate timing. 
     In addition, when there are no shoes of the shoe color  131 D matching the designated color  111 E, the purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of the predetermined approximate color associated with the designated color  111 E, whereby it becomes easy for the user to purchase the shoes of a similar color even if the color does not completely match the color designated by the user. 
     In addition, when there are no shoes for the application genre  131 C matching the designated genre  111 D, the purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes for a predetermined similar genre, which is a sports genre similar to the designated genre  111 D, whereby the purchase of the shoes for sports that are close in form of competition to the sports genre designated by the user can be recommend at an appropriate timing. 
     In addition, the sporting ability measurement value  111 F, which is a measurement result for the sporting ability of the user, is included in the user data  111 , information on the desired sporting ability value  131 E indicating the sporting ability coupled with each pair of shoes is included in the product information, and the purchase recommendation processing unit  14  determines the purchase-recommended product by prioritizing the shoes of which the desired sporting ability value  131 E is equal to or less than the sporting ability measurement value  111 F, from among the shoes fitting to the change prediction value, whereby the purchase of the shoes suited to the sporting ability of the user can be recommended at an appropriate timing. 
     In addition, the stock information  131 F indicating whether or not the shoes are in stock is included in the product information  131 , and the purchase recommendation processing unit  14  determines the purchase-recommended product from among the shoes in stock, whereby the purchase of the shoes that are not out of stock can be recommended to the user. 
     A shoe purchase recommendation device according to the present invention has an effect of enabling to allow a user to utilize information on a foot size of another person as a criterion to decide as to whether or not to purchase shoes. 
     The configurations indicated in the above embodiments illustrate examples of the content of the present invention and can be combined with another known technique. A part of the configurations can be omitted or altered without departing from the gist of the present invention.