Patent Publication Number: US-2023162139-A1

Title: Systems and methods for inventory estimation

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to computerized systems and methods for target inventory estimation. In particular, embodiments of the present disclosure relate to inventive and unconventional systems relate to estimation of the target inventory for an item in a geographical region. 
     BACKGROUND 
     Distribution of items to sale and delivery location is an important challenge for retail and wholesale service provider to achieve cheap and timely delivery of ordered items. Most of the current systems and methods to decide the amount of inventory needed to serve uncertain demand require knowledge of the full probability distribution of the demand. However, this full knowledge is rarely available in practice. This is especially true for items with limited data, such as new items, seasonal items, or slow-selling items. Limited data can make it difficult for the current system techniques to make accurate predictions of demand at various sale and delivery locations. Typically, decision makers have estimates for the mean and variance of the demand, and may be willing to make some weak additional assumption (e.g. unimodality), but no additional information about its probability distribution is known. 
     There are comparatively few existing methods for inventory management that use only partial information about the demand distribution. These methods typically try to minimize an expected cost under the worst possible demand distribution that is compatible with the known information. Notable examples of this so-called min-max approach are Scarf (1957), Gallego and Moon (1993), and Perakis and Roels (2008). Other methods use so-called robust optimization techniques, like those presented in 
     Bertsimas and Thiele (2006), See and Sim (2010), or Mamani, Nassiri, and Wagner (2017). However, all the above methods require the specification of a cost function that includes components that are hard for practitioners to quantify (like the loss of customer goodwill induced by out-of-stocks). Many practitioners prefer to design their inventory management decisions to satisfy a desired quality of service constraint (like a desired in stock rate) rather than minimize a hard to quantify cost. While one can in principle adapt robust optimization techniques like those in Bertsimas and Thiele (2006) to deal with quality of service constraints, these methods use computationally intensive optimization techniques that cannot be scaled to repeatedly making inventory decisions for millions of different items, as is typical in an online retail setting. Existing systems techniques also do not consider the capabilities of item sale and delivery locations. 
     Therefore, there is a need for inventory management systems that (i) use only limited information about the demand distribution, like mean, variance, and unimodality; (ii) are designed to guarantee desired quality of service constraints; and (iii) are not computationally intensive, so that they can easily scale to making periodic inventory decisions for millions of items. 
     SUMMARY 
     One aspect of the present disclosure is directed to a system for target inventory estimation of a geographical region. The system includes at least one non transitory storage medium comprising instructions and at least one processor executing the instructions for performing operations. The operations may include receive an item identifier associated with an item for inventory estimation as an input to the system for target inventory estimation for the item in a geographical region, access demand share estimate and mean and variance estimates of the demand share estimate of the item associated with the received item identifier in the geographical region, determine overall demand forecast of the item associated with the received item identifier, wherein the overall demand forecast of the item is based on order data associated with the item, calculate mean and variance estimates of the overall demand forecast of the item associated with the received item identifier, wherein the mean and variance estimates of the overall demand forecast of the item is based on previously determined overall demand forecast of the item, determine service level associated with the geographical region, wherein the service level of the geographical region is based on availability of one or more items at the geographical region to satisfy orders for the one or more items, generate target inventory estimation of the item associated with the received item identifier in the geographical region based on the mean and variance estimates of the overall demand forecast of the item, mean and variance estimate of the demand share estimate of the item in the geographical region, wherein the generated target inventory estimation meets the service level of the geographical region, and respond to the received item identifier with the generated target inventory estimation. 
     Another aspect of the present disclosure is directed to a method for target inventory estimation of a geographical region. The method comprising: receiving an item identifier associated with an item for inventory estimation as input to the system for target inventory estimation for the item in a geographical region, accessing demand share estimate and mean and variance estimates of the demand share estimate of the item associated with the received item identifier in the geographical region, determining overall demand forecast of the item associated with the received item identifier, wherein the overall demand forecast of the item is based on order data associated with the item, calculating mean and variance estimates of the overall demand forecast of the item associated with the received item identifier, wherein the mean and variance estimates of the overall demand forecast of the item is based on previously determined overall demand forecast of the item, determining service level associated with the geographical region, wherein the service level of the geographical region is based on availability of one or more items at the geographical region to satisfy order for the one or more items, generating target inventory estimation of the item associated with the received item identifier in the geographical region based on the mean and variance estimates of the overall demand forecast of the item, mean and variance estimates of the demand share estimate of the item in the geographical region, wherein the generated target inventory estimation meets the service level of the geographical region, and responding to the received item identifier with the generated target inventory estimation. 
     Yet another aspect of the present disclosure is directed to a system for target inventory estimation of a geographical region. The system may include at least one non transitory storage medium comprising instructions and at least one processor executing instructions for performing operations. The operations may include receive an item identifier associated with an item for inventory estimation as an input to the system for target inventory estimation for the item in a geographical region, access demand share estimate and mean and variance estimates of the demand share estimate of the item associated with the received item identifier in the geographical region, determine overall demand forecast of the item associated with the received item identifier, wherein the overall demand forecast of the item is based on order data associated with the item, calculate mean and variance estimates of the overall demand forecast of the item associated with the received item identifier, wherein the mean and variance estimates of the overall demand forecast of the item is based on previously determined overall demand forecast of the item, determine service level associated with the geographical region, wherein the service level of the geographical region is based on availability of one or more items at the geographical region to satisfy orders for the one or more items, generate target inventory estimation of the item associated with the received item identifier in the geographical region is based on the mean and variance estimates of the overall demand forecast of the item, mean and variance estimate of the demand share estimate of the item in the geographical region wherein the generated target inventory estimation meets the service level of the geographical region, generate target inventory estimation of the item associated with the received item identifier in a first set of geographical regions of the sets of geographical regions based on the mean and variance estimates of the overall demand forecast of the item, mean and variance estimates of the demand share estimate of the item in the geographical region wherein the generated target inventory estimation of item in the first set of geographical regions meets the service level of the first set of geographical regions, wherein the first set of geographical regions is associated with a first service type, aggregate a second set of geographical regions of the sets of geographical regions, wherein the second set of geographical regions is associated with second service type, generate target inventory estimation for the combined target inventory estimation for the first service and second service type, wherein the combined target inventory estimation for the first service type and the second service type is based on aggregation of the target inventor estimation of the first set of geographical regions and the second set of geographical regions, and respond to the received item identifier with the generated target inventory estimation for the combined target inventory estimation for the first service and second service type. 
     Other systems, methods, and computer-readable media are also discussed herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a schematic block diagram illustrating an exemplary embodiment of a network comprising computerized systems for communications enabling shipping, transportation, and logistics operations, consistent with the disclosed embodiments. 
         FIG.  1 B  depicts a sample Search Result Page (SRP) that includes one or more search results satisfying a search request along with interactive user interface elements, consistent with the disclosed embodiments. 
         FIG.  1 C  depicts a sample Single Detail Page (SDP) that includes a product and information about the product along with interactive user interface elements, consistent with the disclosed embodiments. 
         FIG.  1 D  depicts a sample Cart page that includes items in a virtual shopping cart along with interactive user interface elements, consistent with the disclosed embodiments. 
         FIG.  1    E depicts a sample Order page that includes items from the virtual shopping cart along with information regarding purchase and shipping, along with interactive user interface elements, consistent with the disclosed embodiments. 
         FIG.  2    is a diagrammatic illustration of an exemplary fulfillment center configured to utilize disclosed computerized systems, consistent with the disclosed embodiments. 
         FIG.  3    is a block diagram of exemplary target inventory estimation system, consistent with the disclosed embodiments. 
         FIG.  4    illustrates a schematic diagram of an exemplary server of a distributed system, according to some embodiments of the present disclosure. 
         FIG.  5    illustrates a hierarchical set of geographical regions for inventory management, consistent with the disclosed embodiments. 
         FIG.  6    is an illustrative flow chart of a method for determining inventory estimation of an item in a geographical region, consistent with the disclosed embodiments. 
         FIG.  7    is an illustrative flow chart of a method for determining target inventory estimation of an item at multiple geographical regions offering different services, consistent with the disclosed embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar parts. While several illustrative embodiments are described herein, modifications, adaptations and other implementations are possible. For example, substitutions, additions, or modifications may be made to the components and steps illustrated in the drawings, and the illustrative methods described herein may be modified by substituting, reordering, removing, or adding steps to the disclosed methods. Accordingly, the following detailed description is not limited to the disclosed embodiments and examples. Instead, the proper scope of the invention is defined by the appended claims. 
     Embodiments of the present disclosure are directed to systems and methods configured for learning and predicting the sale and delivery patterns of new items and seasonal utilization variations of existing items. A system may gain this intelligence using machine learning models that can handle large amounts of item utilization data as training data to predict item utilization patterns. Item utilization data may include items order processing at sale and delivery centers. The system can also handle limited data availability circumstances by providing the data as input to previously training machine learning models with related item data. By able to predict item utilization patterns the system can understand target inventory estimation of items and make distribution estimates of items. 
     Referring to  FIG.  1 A , a schematic block diagram  100  illustrating an exemplary embodiment of a system comprising computerized systems for communications enabling shipping, transportation, and logistics operations is shown. As illustrated in  FIG.  1 A , system  100  may include a variety of systems, each of which may be connected to one another via one or more networks. The systems may also be connected to one another via a direct connection, for example, using a cable. The depicted systems include a shipment authority technology (SAT) system  101 , an external front end system  103 , an internal front end system  105 , a transportation system  107 , mobile devices  107 A,  107 B, and  107 C, seller portal  109 , shipment and order tracking (SOT) system  111 , fulfillment optimization (FO) system  113 , fulfillment messaging gateway (FMG)  115 , supply chain management (SCM) system  117 , warehouse management system  119 , mobile devices  119 A,  119 B, and  119 C (depicted as being inside of fulfillment center (FC)  200 ), 3rd party fulfillment systems  121 A,  121 B, and  121 C, fulfillment center authorization system (FC Auth)  123 , and labor management system (LMS)  125 . 
     SAT system  101 , in some embodiments, may be implemented as a computer system that monitors order status and delivery status. For example, SAT system  101  may determine whether an order is past its Promised Delivery Date (PDD) and may take appropriate action, including initiating a new order, reshipping the items in the non-delivered order, canceling the non-delivered order, initiating contact with the ordering customer, or the like. SAT system  101  may also monitor other data, including output (such as a number of packages shipped during a particular time period) and input (such as the number of empty cardboard boxes received for use in shipping). SAT system  101  may also act as a gateway between different devices in system  100 , enabling communication (e.g., using store-and-forward or other techniques) between devices such as external front end system  103  and FO system  113 . 
     External front end system  103 , in some embodiments, may be implemented as a computer system that enables external users to interact with one or more systems in system  100 . For example, in embodiments where system  100  enables the presentation of systems to enable users to place an order for an item, external front end system  103  may be implemented as a web server that receives search requests, presents item pages, and solicits payment information. For example, external front end system  103  may be implemented as a computer or computers running software such as the Apache HTTP Server, Microsoft Internet Information Services (IIS), NGINX, or the like. In other embodiments, external front end system  103  may run custom web server software designed to receive and process requests from external devices (e.g., mobile device  102 A or computer  102 B), acquire information from databases and other data stores based on those requests, and provide responses to the received requests based on acquired information. 
     In some embodiments, external front end system  103  may include one or more of a web caching system, a database, a search system, or a payment system. In one aspect, external front end system  103  may comprise one or more of these systems, while in another aspect, external front end system  103  may comprise interfaces (e.g., server-to-server, database-to-database, or other network connections) connected to one or more of these systems. 
     An illustrative set of steps, illustrated by  FIGS.  1 B,  1 C,  1 D, and  1 E , will help to describe some operations of external front end system  103 . External front end system  103  may receive information from systems or devices in system  100  for presentation and/or display. For example, external front end system  103  may host or provide one or more web pages, including a Search Result Page (SRP) (e.g.,  FIG.  1 B ), a Single Detail Page (SDP) (e.g.,  FIG.  1 C ), a Cart page (e.g.,  FIG.  1 D ), or an Order page (e.g.,  FIG.  1 E ). A user device (e.g., using mobile device  102 A or computer  102 B) may navigate to external front end system  103  and request a search by entering information into a search box. External front end system  103  may request information from one or more systems in system  100 . For example, external front end system  103  may request information from FO System  113  that satisfies the search request. External front end system  103  may also request and receive (from FO System  113 ) a Promised Delivery Date or “PDD” for each product included in the search results. The PDD, in some embodiments, may represent an estimate of when a package containing the product will arrive at the user&#39;s desired location or a date by which the product is promised to be delivered at the user&#39;s desired location if ordered within a particular period of time, for example, by the end of the day (11:59 PM). (PDD is discussed further below with respect to FO System  113 .) 
     External front end system  103  may prepare an SRP (e.g.,  FIG.  1 B ) based on the information. The SRP may include information that satisfies the search request. For example, this may include pictures of products that satisfy the search request. The SRP may also include respective prices for each product, or information relating to enhanced delivery options for each product, PDD, weight, size, offers, discounts, or the like. External front end system  103  may send the SRP to the requesting user device (e.g., via a network). 
     A user device may then select a product from the SRP, e.g., by clicking or tapping a user interface, or using another input device, to select a product represented on the SRP. The user device may formulate a request for information on the selected product and send it to external front end system  103 . In response, external front end system  103  may request information related to the selected product. For example, the information may include additional information beyond that presented for a product on the respective SRP. This could include, for example, shelf life, country of origin, weight, size, number of items in package, handling instructions, or other information about the product. The information could also include recommendations for similar products (based on, for example, big data and/or machine learning analysis of customers who bought this product and at least one other product), answers to frequently asked questions, reviews from customers, manufacturer information, pictures, or the like. 
     External front end system  103  may prepare an SDP (Single Detail Page) (e.g.,  FIG.  1 C ) based on the received product information. The SDP may also include other interactive elements such as a “Buy Now” button, a “Add to Cart” button, a quantity field, a picture of the item, or the like. The SDP may further include a list of sellers that offer the product. The list may be ordered based on the price each seller offers such that the seller that offers to sell the product at the lowest price may be listed at the top. The list may also be ordered based on the seller ranking such that the highest ranked seller may be listed at the top. The seller ranking may be formulated based on multiple factors, including, for example, the seller&#39;s past track record of meeting a promised PDD. External front end system  103  may deliver the SDP to the requesting user device (e.g., via a network). 
     The requesting user device may receive the SDP which lists the product information. Upon receiving the SDP, the user device may then interact with the SDP. For example, a user of the requesting user device may click or otherwise interact with a “Place in Cart” button on the SDP. This adds the product to a shopping cart associated with the user. The user device may transmit this request to add the product to the shopping cart to external front end system  103 . 
     External front end system  103  may generate a Cart page (e.g.,  FIG.  1 D ). The Cart page, in some embodiments, lists the products that the user has added to a virtual “shopping cart.” A user device may request the Cart page by clicking on or otherwise interacting with an icon on the SRP, SDP, or other pages. The Cart page may, in some embodiments, list all products that the user has added to the shopping cart, as well as information about the products in the cart such as a quantity of each product, a price for each product per item, a price for each product based on an associated quantity, information regarding PDD, a delivery method, a shipping cost, user interface elements for modifying the products in the shopping cart (e.g., deletion or modification of a quantity), options for ordering other product or setting up periodic delivery of products, options for setting up interest payments, user interface elements for proceeding to purchase, or the like. A user at a user device may click on or otherwise interact with a user interface element (e.g., a button that reads “Buy Now”) to initiate the purchase of the product in the shopping cart. Upon doing so, the user device may transmit this request to initiate the purchase to external front end system  103 . 
     External front end system  103  may generate an Order page (e.g.,  FIG.  1 E ) in response to receiving the request to initiate a purchase. The Order page, in some embodiments, re-lists the items from the shopping cart and requests input of payment and shipping information. For example, the Order page may include a section requesting information about the purchaser of the items in the shopping cart (e.g., name, address, e-mail address, phone number), information about the recipient (e.g., name, address, phone number, delivery information), shipping information (e.g., speed/method of delivery and/or pickup), payment information (e.g., credit card, bank transfer, check, stored credit), user interface elements to request a cash receipt (e.g., for tax purposes), or the like. External front end system  103  may send the Order page to the user device. 
     The user device may enter information on the Order page and click or otherwise interact with a user interface element that sends the information to external front end system  103 . From there, external front end system  103  may send the information to different systems in system  100  to enable the creation and processing of a new order with the products in the shopping cart. 
     In some embodiments, external front end system  103  may be further configured to enable sellers to transmit and receive information relating to orders. 
     Internal front end system  105 , in some embodiments, may be implemented as a computer system that enables internal users (e.g., employees of an organization that owns, operates, or leases system  100 ) to interact with one or more systems in system  100 . For example, in embodiments where system  100  enables the presentation of systems to enable users to place an order for an item, internal front end system  105  may be implemented as a web server that enables internal users to view diagnostic and statistical information about orders, modify item information, or review statistics relating to orders. For example, internal front end system  105  may be implemented as a computer or computers running software such as the Apache HTTP Server, Microsoft Internet Information Services (IIS), NGINX, or the like. In other embodiments, internal front end system  105  may run custom web server software designed to receive and process requests from systems or devices depicted in system  100  (as well as other devices not depicted), acquire information from databases and other data stores based on those requests, and provide responses to the received requests based on acquired information. 
     In some embodiments, internal front end system  105  may include one or more of a web caching system, a database, a search system, a payment system, an analytics system, an order monitoring system, or the like. In one aspect, internal front end system  105  may comprise one or more of these systems, while in another aspect, internal front end system  105  may comprise interfaces (e.g., server-to-server, database-to-database, or other network connections) connected to one or more of these systems. 
     Transportation system  107 , in some embodiments, may be implemented as a computer system that enables communication between systems or devices in system  100  and mobile devices  107 A- 107 C. Transportation system  107 , in some embodiments, may receive information from one or more mobile devices  107 A- 107 C (e.g., mobile phones, smart phones, PDAs, or the like). For example, in some embodiments, mobile devices  107 A- 107 C may comprise devices operated by delivery workers. The delivery workers, who may be permanent, temporary, or shift employees, may utilize mobile devices  107 A- 107 C to effect delivery of packages containing the products ordered by users. For example, to deliver a package, the delivery worker may receive a notification on a mobile device indicating which package to deliver and where to deliver it. Upon arriving at the delivery location, the delivery worker may locate the package (e.g., in the back of a truck or in a crate of packages), scan or otherwise capture data associated with an identifier on the package (e.g., a barcode, an image, a text string, an RFID tag, or the like) using the mobile device, and deliver the package (e.g., by leaving it at a front door, leaving it with a security guard, handing it to the recipient, or the like). In some embodiments, the delivery worker may capture photo(s) of the package and/or may obtain a signature using the mobile device. The mobile device may send information to transportation system  107  including information about the delivery, including, for example, time, date, GPS location, photo(s), an identifier associated with the delivery worker, an identifier associated with the mobile device, or the like. Transportation system  107  may store this information in a database (not pictured) for access by other systems in system  100 . Transportation system  107  may, in some embodiments, use this information to prepare and send tracking data to other systems indicating the location of a particular package. 
     In some embodiments, certain users may use one kind of mobile device (e.g., permanent workers may use a specialized PDA with custom hardware such as a barcode scanner, stylus, and other devices) while other users may use other kinds of mobile devices (e.g., temporary or shift workers may utilize off-the-shelf mobile phones and/or smartphones). 
     In some embodiments, transportation system  107  may associate a user with each device. For example, transportation system  107  may store an association between a user (represented by, e.g., a user identifier, an employee identifier, or a phone number) and a mobile device (represented by, e.g., an International Mobile Equipment Identity (IMEI), an International Mobile Subscription Identifier (IMSI), a phone number, a Universal Unique Identifier (UUID), or a Globally Unique Identifier (GUID)). Transportation system  107  may use this association in conjunction with data received on deliveries to analyze data stored in the database in order to determine, among other things, a location of the worker, an efficiency of the worker, or a speed of the worker. 
     Seller portal  109 , in some embodiments, may be implemented as a computer system that enables sellers or other external entities to electronically communicate with one or more systems in system  100 . For example, a seller may utilize a computer system (not pictured) to upload or provide product information, order information, contact information, or the like, for products that the seller wishes to sell through system  100  using seller portal  109 . 
     Shipment and order tracking system  111 , in some embodiments, may be implemented as a computer system that receives, stores, and forwards information regarding the location of packages containing products ordered by customers (e.g., by a user using devices  102 A- 102 B). In some embodiments, shipment and order tracking system  111  may request or store information from web servers (not pictured) operated by shipping companies that deliver packages containing products ordered by customers. 
     In some embodiments, shipment and order tracking system  111  may request and store information from systems depicted in system  100 . For example, shipment and order tracking system  111  may request information from transportation system  107 . As discussed above, transportation system  107  may receive information from one or more mobile devices  107 A- 107 C (e.g., mobile phones, smart phones, PDAs, or the like) that are associated with one or more of a user (e.g., a delivery worker) or a vehicle (e.g., a delivery truck). In some embodiments, shipment and order tracking system  111  may also request information from warehouse management system (WMS)  119  to determine the location of individual products inside of a fulfillment center (e.g., fulfillment center  200 ). Shipment and order tracking system  111  may request data from one or more of transportation system  107  or WMS  119 , process it, and present it to a device (e.g., user devices  102 A and  102 B) upon request. 
     Fulfillment optimization (FO) system  113 , in some embodiments, may be implemented as a computer system that stores information for customer orders from other systems (e.g., external front end system  103  and/or shipment and order tracking system  111 ). FO system  113  may also store information describing where particular items are held or stored. For example, certain items may be stored only in one fulfillment center, while certain other items may be stored in multiple fulfillment centers. In still other embodiments, certain fulfilment centers may be designed to store only a particular set of items (e.g., fresh produce or frozen products). FO system  113  stores this information as well as associated information (e.g., quantity, size, date of receipt, expiration date, etc.). 
     FO system  113  may also calculate a corresponding PDD (promised delivery date) for each product. The PDD, in some embodiments, may be based on one or more factors. For example, FO system  113  may calculate a PDD for a product based on a past demand for a product (e.g., how many times that product was ordered during a period of time), an expected demand for a product (e.g., how many customers are forecast to order the product during an upcoming period of time), a network-wide past demand indicating how many products were ordered during a period of time, a network-wide expected demand indicating how many products are expected to be ordered during an upcoming period of time, one or more counts of the product stored in each fulfillment center  200 , which fulfillment center stores each product, expected or current orders for that product, or the like. 
     In some embodiments, FO system  113  may determine a PDD for each product on a periodic basis (e.g., hourly) and store it in a database for retrieval or sending to other systems (e.g., external front end system  103 , SAT system  101 , shipment and order tracking system  111 ). In other embodiments, FO system  113  may receive electronic requests from one or more systems (e.g., external front end system  103 , SAT system  101 , shipment and order tracking system  111 ) and calculate the PDD on demand. 
     Fulfilment messaging gateway (FMG)  115 , in some embodiments, may be implemented as a computer system that receives a request or response in one format or protocol from one or more systems in system  100 , such as FO system  113 , converts it to another format or protocol, and forward it in the converted format or protocol to other systems, such as WMS  119  or 3rd party fulfillment systems  121 A,  121 B, or  121 C, and vice versa. 
     Supply chain management (SCM) system  117 , in some embodiments, may be implemented as a computer system that performs forecasting functions. For example, SCM system  117  may forecast a level of demand for a particular product based on, for example, based on a past demand for products, an expected demand for a product, a network-wide past demand, a network-wide expected demand, a count of products stored in each fulfillment center  200 , expected or current orders for each product, or the like. In response to this forecasted level and the amount of each product across all fulfillment centers, SCM system  117  may generate one or more purchase orders to purchase and stock a sufficient quantity to satisfy the forecasted demand for a particular product. 
     Warehouse management system (WMS)  119 , in some embodiments, may be implemented as a computer system that monitors workflow. For example, WMS  119  may receive event data from individual devices (e.g., devices  107 A- 107 C or  119 A- 119 C) indicating discrete events. For example, WMS  119  may receive event data indicating the use of one of these devices to scan a package. As discussed below with respect to fulfillment center  200  and  FIG.  2   , during the fulfillment process, a package identifier (e.g., a barcode or RFID tag data) may be scanned or read by machines at particular stages (e.g., automated or handheld barcode scanners, RFID readers, high-speed cameras, devices such as tablet  119 A, mobile device/PDA  1198 , computer  119 C, or the like). WMS  119  may store each event indicating a scan or a read of a package identifier in a corresponding database (not pictured) along with the package identifier, a time, date, location, user identifier, or other information, and may provide this information to other systems (e.g., shipment and order tracking system  111 ). 
     WMS  119 , in some embodiments, may store information associating one or more devices (e.g., devices  107 A- 107 C or  119 A- 119 C) with one or more users associated with system  100 . For example, in some situations, a user (such as a part- or full-time employee) may be associated with a mobile device in that the user owns the mobile device (e.g., the mobile device is a smartphone). In other situations, a user may be associated with a mobile device in that the user is temporarily in custody of the mobile device (e.g., the user checked the mobile device out at the start of the day, will use it during the day, and will return it at the end of the day). 
     WMS  119 , in some embodiments, may maintain a work log for each user associated with system  100 . For example, WMS  119  may store information associated with each employee, including any assigned processes (e.g., unloading trucks, picking items from a pick zone, rebin wall work, packing items), a user identifier, a location (e.g., a floor or zone in a fulfillment center  200 ), a number of units moved through the system by the employee (e.g., number of items picked, number of items packed), an identifier associated with a device (e.g., devices  119 A- 119 C), or the like. In some embodiments, WMS  119  may receive check-in and check-out information from a timekeeping system, such as a timekeeping system operated on a device  119 A- 119 C. 
     3rd party fulfillment ( 3 PL) systems  121 A- 121 C, in some embodiments, represent computer systems associated with third-party providers of logistics and products. For example, while some products are stored in fulfillment center  200  (as discussed below with respect to  FIG.  2   ), other products may be stored off-site, may be produced on demand, or may be otherwise unavailable for storage in fulfillment center  200 .  3 PL systems  121 A- 121 C may be configured to receive orders from FO system  113  (e.g., through FMG  115 ) and may provide products and/or services (e.g., delivery or installation) to customers directly. In some embodiments, one or more of  3 PL systems  121 A- 121 C may be part of system  100 , while in other embodiments, one or more of  3 PL systems  121 A- 121 C may be outside of system  100  (e.g., owned or operated by a third-party provider). 
     Fulfillment Center Auth system (FC Auth)  123 , in some embodiments, may be implemented as a computer system with a variety of functions. For example, in some embodiments, FC Auth  123  may act as a single-sign on (SSO) service for one or more other systems in system  100 . For example, FC Auth  123  may enable a user to log in via internal front end system  105 , determine that the user has similar privileges to access resources at shipment and order tracking system  111 , and enable the user to access those privileges without requiring a second log in process. FC Auth  123 , in other embodiments, may enable users (e.g., employees) to associate themselves with a particular task. For example, some employees may not have an electronic device (such as devices  119 A- 119 C) and may instead move from task to task, and zone to zone, within a fulfillment center  200 , during the course of a day. FC Auth  123  may be configured to enable those employees to indicate what task they are performing and what zone they are in at different times of day. 
     Labor management system (LMS)  125 , in some embodiments, may be implemented as a computer system that stores attendance and overtime information for employees (including full-time and part-time employees). For example, LMS  125  may receive information from FC Auth  123 , WMS  119 , devices  119 A- 119 C, transportation system  107 , and/or devices  107 A- 107 C. 
     The particular configuration depicted in  FIG.  1 A  is an example only. For example, while  FIG.  1 A  depicts FC Auth system  123  connected to FO system  113 , not all embodiments require this particular configuration. Indeed, in some embodiments, the systems in system  100  may be connected to one another through one or more public or private networks, including the Internet, an Intranet, a WAN (Wide-Area Network), a MAN (Metropolitan-Area Network), a wireless network compliant with the IEEE 802.11a/b/g/n Standards, a leased line, or the like. In some embodiments, one or more of the systems in system  100  may be implemented as one or more virtual servers implemented at a data center, server farm, or the like. 
       FIG.  2    depicts a fulfillment center  200 . Fulfillment center  200  is an example of a physical location that stores items for shipping to customers when ordered. Fulfillment center (FC)  200  may be divided into multiple zones, each of which are depicted in  FIG.  2   . These “zones,” in some embodiments, may be thought of as virtual divisions between different stages of a process of receiving items, storing the items, retrieving the items, and shipping the items. So while the “zones” are depicted in  FIG.  2   , other divisions of zones are possible, and the zones in  FIG.  2    may be omitted, duplicated, or modified in some embodiments. 
     Inbound zone  203  represents an area of FC  200  where items are received from sellers who wish to sell products using system  100  from  FIG.  1 A . For example, a seller may deliver items  202 A and  202 B using truck  201 . Item  202 A may represent a single item large enough to occupy its own shipping pallet, while item  202 B may represent a set of items that are stacked together on the same pallet to save space. 
     A worker will receive the items in inbound zone  203  and may optionally check the items for damage and correctness using a computer system (not pictured). For example, the worker may use a computer system to compare the quantity of items  202 A and  202 B to an ordered quantity of items. If the quantity does not match, that worker may refuse one or more of items  202 A or  202 B. If the quantity does match, the worker may move those items (using, e.g., a dolly, a handtruck, a forklift, or manually) to buffer zone  205 . Buffer zone  205  may be a temporary storage area for items that are not currently needed in the picking zone, for example, because there is a high enough quantity of that item in the picking zone to satisfy forecasted demand. In some embodiments, forklifts  206  operate to move items around buffer zone  205  and between inbound zone  203  and drop zone  207 . If there is a need for items  202 A or  202 B in the picking zone (e.g., because of forecasted demand), a forklift may move items  202 A or  202 B to drop zone  207 . 
     Drop zone  207  may be an area of FC  200  that stores items before they are moved to picking zone  209 . A worker assigned to the picking task (a “picker”) may approach items  202 A and  202 B in the picking zone, scan a barcode for the picking zone, and scan barcodes associated with items  202 A and  202 B using a mobile device (e.g., device  119 B). The picker may then take the item to picking zone  209  (e.g., by placing it on a cart or carrying it). 
     Picking zone  209  may be an area of FC  200  where items  208  are stored on storage units  210 . In some embodiments, storage units  210  may comprise one or more of physical shelving, bookshelves, boxes, totes, refrigerators, freezers, cold stores, or the like. In some embodiments, picking zone  209  may be organized into multiple floors. In some embodiments, workers or machines may move items into picking zone  209  in multiple ways, including, for example, a forklift, an elevator, a conveyor belt, a cart, a handtruck, a dolly, an automated robot or device, or manually. For example, a picker may place items  202 A and  202 B on a handtruck or cart in drop zone  207  and walk items  202 A and  202 B to picking zone  209 . 
     A picker may receive an instruction to place (or “stow”) the items in particular spots in picking zone  209 , such as a particular space on a storage unit  210 . For example, a picker may scan item  202 A using a mobile device (e.g., device  119 B). The device may indicate where the picker should stow item  202 A, for example, using a system that indicate an aisle, shelf, and location. The device may then prompt the picker to scan a barcode at that location before stowing item  202 A in that location. The device may send (e.g., via a wireless network) data to a computer system such as WMS  119  in  FIG.  1 A  indicating that item  202 A has been stowed at the location by the user using device  1196 . 
     Once a user places an order, a picker may receive an instruction on device  1196  to retrieve one or more items  208  from storage unit  210 . The picker may retrieve item  208 , scan a barcode on item  208 , and place it on transport mechanism  214 . While transport mechanism  214  is represented as a slide, in some embodiments, transport mechanism may be implemented as one or more of a conveyor belt, an elevator, a cart, a forklift, a handtruck, a dolly, or the like. Item  208  may then arrive at packing zone  211 . 
     Packing zone  211  may be an area of FC  200  where items are received from picking zone  209  and packed into boxes or bags for eventual shipping to customers. In packing zone  211 , a worker assigned to receiving items (a “rebin worker”) will receive item  208  from picking zone  209  and determine what order it corresponds to. For example, the rebin worker may use a device, such as computer  119 C, to scan a barcode on item  208 . Computer  119 C may indicate visually which order item  208  is associated with. This may include, for example, a space or “cell” on a wall  216  that corresponds to an order. Once the order is complete (e.g., because the cell contains all items for the order), the rebin worker may indicate to a packing worker (or “packer”) that the order is complete. The packer may retrieve the items from the cell and place them in a box or bag for shipping. The packer may then send the box or bag to a hub zone  213 , e.g., via forklift, cart, dolly, handtruck, conveyor belt, manually, or otherwise. 
     Hub zone  213  may be an area of FC  200  that receives all boxes or bags (“packages”) from packing zone  211 . Workers and/or machines in hub zone  213  may retrieve package  218  and determine which portion of a delivery area each package is intended to go to, and route the package to an appropriate camp zone  215 . For example, if the delivery area has two smaller sub-areas, packages will go to one of two camp zones  215 . In some embodiments, a worker or machine may scan a package (e.g., using one of devices  119 A- 119 C) to determine its eventual destination. Routing the package to camp zone  215  may comprise, for example, determining a portion of a geographical area that the package is destined for (e.g., based on a postal code) and determining a camp zone  215  associated with the portion of the geographical area. 
     Camp zone  215 , in some embodiments, may comprise one or more buildings, one or more physical spaces, or one or more areas, where packages are received from hub zone  213  for sorting into routes and/or sub-routes. In some embodiments, camp zone  215  is physically separate from FC  200  while in other embodiments camp zone  215  may form a part of FC  200 . 
     Workers and/or machines in camp zone  215  may determine which route and/or sub-route a package  220  should be associated with, for example, based on a comparison of the destination to an existing route and/or sub-route, a calculation of workload for each route and/or sub-route, the time of day, a shipping method, the cost to ship the package  220 , a PDD associated with the items in package  220 , or the like. In some embodiments, a worker or machine may scan a package (e.g., using one of devices  119 A- 119 C) to determine its eventual destination. Once package  220  is assigned to a particular route and/or sub-route, a worker and/or machine may move package  220  to be shipped. In exemplary  FIG.  2   , camp zone  215  includes a truck  222 , a car  226 , and delivery workers  224 A and  224 B. In some embodiments, truck  222  may be driven by delivery worker  224 A, where delivery worker  224 A is a full-time employee that delivers packages for FC  200  and truck  222  is owned, leased, or operated by the same company that owns, leases, or operates FC  200 . In some embodiments, car  226  may be driven by delivery worker  224 B, where delivery worker  224 B is a “flex” or occasional worker that is delivering on an as-needed basis (e.g., seasonally). Car  226  may be owned, leased, or operated by delivery worker  224 B. 
       FIG.  3    is a block diagram of an exemplary target inventory estimation system, consistent with the disclosed embodiments. As illustrated in  FIG.  3   , inventory estimation system  310  connects with data store  320  and user device  330  over network  340 . Inventory estimation system  310  components may include forecast module  311 , service level module  312 , demand share module  313 , target inventory module  314 . 
     Inventory estimation system  310 , in some embodiments, may be implemented as a computer system that performs forecasting item target inventory estimation for a specified region. Each component in inventory estimation system  310  may represent a software program function or the whole software program(s). A processor (for example processors  416 - 417  of  FIG.  4   ) can execute software functions and programs representing components in a target inventory estimation system. The processor can be a virtual or physical processor of a computing device. Computing devices executing the software functions or programs may include a single processor or core or multiple processors or cores or maybe multiple computing devices spread across a distributed computing environment, network, cloud, or virtualized computing environment. 
     Forecast module  311  may forecast the overall demand for an item based on the data related to the item&#39;s orders in data store  320 . Forecast module  311  may also consider searches for the item received by front end system  103  (as shown in  FIG.  1   ) to determine the item&#39;s overall demand. Forecast module  311  may receive an item identifier, such as an SKU number or a barcode for an item, as input to determine the overall demand for the item. User device  330  may share a request with an item identifier to determine the item&#39;s overall demand. In some embodiments, user device  330  may request overall demand data for multiple items. In some embodiments, target inventory module  314  may request forecast module  311  to provide the overall demand forecast for an item. Forecast module  311  may determine the national forecast as overall demand for an item based on the item&#39;s previous orders stored as order data  322 . Inventory estimation system  310  may utilize the overall demand of the item to compute the target inventory estimation for a specific region at a specific time. 
     Service level module  312  may determine service level requirements of various geographical regions served by system  100 . Service level of a geographical region may be a set of requirements that need to be satisfied by system  100  serving item orders in that region. Service level module  312  may manage the target inventory levels at fulfillment centers (e.g., 3rd party fulfillment centers  121 A-C) in a geographical region. Service level module  312  may manage inventory levels by balancing between storage capacity of fulfillment centers in the geographical region and the estimated orders of items that may need to be served by the fulfillment centers in the geographical region. Service level module  312  may need to know the potential orders that may need to be served by the fulfillment centers in the geographical region by reviewing order data  322 . In some embodiments, service level module  312  may communicate with shipment and order tracking system  111  to determine order needs served by a fulfillment center. Fulfillment optimization system  113  may request service level module  312  to determine and help maintain highest service levels in all geographical regions for all items and for all service types (such as overnight shipment, fragile item shipment, etc.). 
     In some embodiments service level module  312  may determine geographical regions to determine service level of each geographical region. Geographical regions identified by service level module  312  may be used to calculate inventory estimation of an item at various granularity levels. Granularity level may indicate the size of geographical region served by system  100  to allow purchase and shipment of items. Granularity levels may define a hierarchy of larger geographical regions at higher levels of granularity which contain smaller geographical regions at lower levels of granularity. For example, granularity levels may include neighborhood, a postal code, a district, state, and country; each region may be included in another larger geographical region where system  100  may ship purchased items. Hierarchy of geographical regions as served by system  100  are described in detail in  FIG.  5    description below. 
     Geographical regions may include portions of overall demand for the item determined by forecast module  311 . Service level module  312  may determine the smallest geographical region for service level determination and target inventory estimation calculation which may be associated with a fulfillment center (e.g., FC  200  of  FIG.  2   ). Service level module  312  may also determine larger geographical regions that may contain the smallest geographical regions. For example, a larger geographical region may contain all 3rd party Fulfillment centers  121 A-C (as shown in  FIG.  1   ). Service level module  312  may determine non-overlapping geographical regions for service level determination and inventory estimation of an item at different geographical granularity levels. Service level module  312 , upon determining the geographical regions related to inventory estimation requested item or service level of a geographical region, may store the data in data store  320 . In some embodiments, inventory estimation system  310  may request service level module  312  to determine all possible regions. 
     Demand share module  313  may determine the share of the overall demand for an item in a geographical region. Demand share module  313  may determine the share of the overall demand by reviewing orders of the item in the identified region. Demand share module  313  may request the shipment and order tracking system  111  (as shown in  FIG.  1   ) for the item&#39;s total orders. In some embodiments, demand share module  313  may review order data  322  directly to identify the order share for each fulfillment center (e.g., FC  200 ) and encompassing geographical regions. Demand share module  313  uses the total order share data to determine the item&#39;s demand share at each geographical region determined by service level module  312 . Demand share module  313  may include a machine learning model trained using item order data to estimate the share of overall future orders. 
     In some embodiments, demand share module  313  may determine the demand share of a set of items related to each other. Demand share module  313  may determine the related items using a pre-defined set of categories. In some embodiments, demand share module  313  may review order data  322  to identify the related items. For example, demand share module  313  may review order data to determine the items&#39; purchase patterns, such as items purchased together to determine the related items. Demand share module  313  may determine each geographical region&#39;s share in the overall demand for the item using overall demand data based on past order data from shipment and order tracking system  111  and expected future orders from forecast module  311  and geographical regions data from service level module  312 . Demand share module  313  may only determine the smallest geographical regions&#39; demand share, such as a fulfillment center (e.g., FC  200 ) alone. 
     Target inventory module  314  may determine the target inventory estimation of an item in a particular region. Target inventory module  314  may compute inventory estimation of an item using demand share estimate of the item in the particular region as computed by demand share module  313 . Target inventory module  314  may distribute the overall demand for an item based on each region&#39;s demand share estimates to calculate the target inventory estimate of a particular region. Target inventory module  314  may rely directly on the demand share based on the amount of order data available in calculating demand shares of geographical regions determined by service level module  312 . In such cases, target inventory module  314  may rely on a set of items related to the item needing inventory estimation determination. Target inventory module  314  may need to compute the target inventory estimate of the set of items related to the item requesting target inventory estimation. 
     Target inventory module  314  may use segment data  324  to determine the set of items associated with the item in need of target inventory estimation. Segment data  324  may include pre-defined segments of item groupings that may be used as sets of related items. In some embodiments, segment data  324  may be populated dynamically by determining the related items forming a set of items grouping. Target inventory module  314  may populate segment data  324  by reviewing order data  322  to find groupings of items purchased together to identify related items. Target inventory module  314  may also communicate with shipment and order tracking system  111  to review item orders to identify related items. For example, items ordered together may be considered related items. In some embodiments, target inventory module  314  may communicate with front end system  103  (as shown in  FIG.  1   ) to determine searches for items conducted and the items reviewed by users of front end system  103  to determine related items to be included as a grouping in segment data  324 . 
     Target module  314 , upon determining the related items to a target inventory estimation of a requested item, may calculate target inventory estimation of the related items. Target inventory module  314  may use demand share estimation of a set of items to compute demand share estimate of a particular item in a particular region. Target inventory module  314  may compute target inventory estimation of multiple geographical regions comprising the requested item target inventory estimation&#39;s particular region. Target inventory module  314  may aggregate the target inventory estimation of multiple geographical regions to calculate an item&#39;s target inventory estimation in a particular region. Target inventory module  314  may determine inventory estimations of geographical regions that meet the service levels of the geographical regions as determined by service level module  312 . Target inventory module  314  may request service level module  312  to provide the service level of the region in which inventory estimation system  310  was request for target inventory estimation of an item. 
     In various embodiments, data store  320  may take several different forms. For example, data store  320  may be an SQL database or NoSQL database, such as those developed by MICROSOFT™, REDIS, ORACLE™, CASSANDRA, MYSQL, various other types of databases, data returned by calling a web service, data returned by calling a computational function, sensor data, IoT devices, or various other data sources. Data store  320  may store data that is used or generated during the operation of applications, such as forecast module  311 , service level module  312 , demand share module  313 , and target inventory module  314 . For example, if service level module  312  is configured to identify regions associated with target inventory estimation, data store  320  may provide item data  321  and order data  322  as information about orders and the items ordered in various regions. Similarly, if inventory estimation system  310  is configured to provide a previously identified segment data  324 , data store  320  may generate segment data  324  associated with an item in data store  320 . In some embodiments, data store  320  may be fed data from an external source, or the external source (e.g., server, database, sensors, IoT devices, etc.) may be a replacement. 
     Item data  321  may include item related information, including item identifier, item name. Item data  321  may also include the availability of an item at various geographical regions such as fulfillment center  200 . SCM system  117  may provide information about the availability of an item at fulfillment center to data store  320  to populate item data  321 . In some embodiments, item data  321  may include item search data provided by front end system  103 . Item data  321  may be tabular data with alphanumeric fields for storing the item identifiers and item names. In some embodiments, item data  321  may be comma separated alphanumeric values. 
     Order data  322  may include item purchase orders as conducted using FO system  113 . Order data  322  include information about various items of item data  321  sold and shipped from various fulfillment centers (e.g., FC  200 , 3rd Party fulfillment centers  121 A-C). Order data  322  may also include tracking data provided by shipment and order tracking system  111 . Order data  322  may be tabular data with alphanumeric fields with information about order shipment address, packaging type (for example, special frozen item packaging), and shipment type (for example, overnight shipment). Order data  322  may be present in other formats such as a comma separated text file or as a JSON file. 
     Forecast data  323  may include the overall demand forecast of items listed in item data  321 . Forecast data  323  may include demand forecast for various geographical regions supported by fulfillment centers. In some embodiments, forecast data  323  may be dynamically populated by forecast module  311 . Forecast data  323  may be structured in a tabular manner with numeric values representing percentage of overall demand. Forecast data  323  may also include whole digit fields indicating the amount of an item needed for satisfying all orders in different geographical regions. 
     Segment data  324  may include data about sets of items of item data  321  related to each other. Segment data  324  may include overlapping sets of items with common items. Segment data  324  may include sets of data as defined for different geographical regions served by system  100 . Segment data  324  may regularly be updated by demand share module  313 . In some embodiments, service level module  312  identification of geographical regions may trigger the determination of new sets of data to store in segment data  324 . Segment data  424  may include alphanumeric fields of item identifiers that together for a segment. Segment data  424  may be structured in other formats such as comma separated values in a text file or as a JSON file. 
     Inventory data  325  may include details of inventory of each item of item data  321 . Item details includes inventory data  325  may include a reference field to the item in item data  321 . The reference field may be a unique item identifier such as a SKU product number or name. Inventory data  325  may include details inventory availability in various geographical regions (such as 3rd party fulfillment centers  121 A-C of  FIG.  1   ). Inventory data  325  may be used along with target inventory estimation determined by inventory estimation system  310  to send the appropriate amount of inventory of an item to a fulfillment center (e.g., 3rd party fulfillment centers  121 A-C). 
     Demand data  326  may include overall demand estimation of an item that can be ordered using front end  103  of system  100 . Demand data  326  may include the mean and variance (standard deviation) of overall demand estimation of the item. In some embodiments, demand data  326  may include demand share data of an item of item data  321  in a geographical region. In some embodiments, demand data  326  may include mean and variance of demand estimation in a particular geographical region and may be calculated using mean and variance of the overall demand estimation and demand share of the geographical region. 
     Geo data  327  may include geographical regions as defined by system  100  based on distribution of fulfillment centers (e.g., fulfillment centers  121 A-C). Requirements of a geographical region may include service level to be met by that region is described below. A detailed description of hierarchical geographical regions with differing service levels is defined in  FIG.  5    description below. 
     Service level data  328  may include service level requirements for item order fulfillment. For example, in some embodiments, the service level of a geographical region may require a certain number of item orders of the total item order to be fulfilled by fulfillment centers in that geographical region. Service level of a geographical region (e.g., sub region  510  of  FIG.  5   ) may be defined by a user of inventory system  310 . Service levels may be defined dynamically by a user of user device  330  connected to inventory system  310  over network  340 . For example, config file  350  may include the configuration for service level of the geographical region where an item&#39;s target inventory estimation is requested. In some embodiments, service level of a geographical region may be based on number of orders of the orders directed to fulfillment centers (e.g., 3rd party fulfillment centers  121 A-C) in the geographical region are met and shipped from those fulfillment centers. Service level values may be stored in service level data  328  and used for future target inventory requests for an item in a geographical region. Service level data  328  may be associated with the geographical regions defined in geo data  327  and items in item data  321 . 
     Service level of a geographical region defined in service level data  328  may need to be refreshed at regular intervals of time. The time interval for refreshing service levels may be defined statically or updated dynamically using a configuration(e.g., inventory estimation request  350 ). In some embodiments, the time interval to refresh service level values of geographical regions may include default values. Service level default values may be determined by a machine learning model. The machine learning model may take as input overall storage and throughput capacities in the fulfillment centers (e.g., FC  200  of  FIG.  2   ) that serve a region. In some embodiments, machine learning model may take as input past order data of order data  322  for the item in a geographical region and the inventory levels of an item from inventory data  325 . 
     System  100  may have triggers for other events to send requests to update service level data of a geographical region in service level data  328 . In some embodiments, inventory estimation system  310  may have the ability to configure target inventory estimation trigger events. A user of inventory estimation system  310  may configure the trigger event for inventory estimation system  310  to refresh service level data in a configuration file (e.g., inventory estimation request  350 ). Service level of a geographical region may be defined based on various factors of items, orders and types of service (such as overnight service). 
     User device  330  may make a request to access target inventory estimation data for a particular region to the modules in inventory estimation system  310 . Modules in inventory estimation system  310  may need to execute one or more functions to retrieve data requested by user device  330 . The execution of the functions may result in database access requests sent by the modules in inventory estimation system  310  to other modules within it. The database access requests sent by modules in inventory estimation system  310  may depend on the type of item or time of day/year. For example, user devices accessing the same item order data may result in different sets of functions of inventory estimation system  310 &#39;s modules executed by a processor to retrieve different item target inventory estimations based on the region and time for target inventory estimations. For instance, if the item is a seasonal item, such as cinnamon flavor, then demand peaks during the holiday season. In addition, in some embodiments, modules in inventory estimation system  310  may be accessed by other automated applications of system  100  without the direct involvement of a user. This may occur, for example, in IoT (Internet of Things) environments, virtualized computing environments (e.g., involving instantiated virtual machines, containers, or serverless code instances), or in other environments involving application-to-application communications. 
     User device  330  may forward target inventory estimation requests to inventory estimation system  310  over network  340 . The requests for information in data store  320  may also optionally be received via network  340 . Network  340  may take various forms. For example, network  340  may include or utilize the Internet, a wired Wide Area Network (WAN), a wired Local Area Network (LAN), a wireless WAN (e.g., WiMAX), a wireless LAN (e.g., IEEE 802.11, etc.), a mesh network, a mobile/cellular network, an enterprise or private data network, a storage area network, a virtual private network using a public network, or other types of network communications. In some embodiments, network  340  may include an on-premises (e.g., LAN) network, while in other embodiments, network  340  may include a virtualized (e.g., AWS™, Azure™, IBM Cloud™, etc.) network. Further, network  340  may in some embodiments be a hybrid on-premises and virtualized network, including components of both types of network architecture. 
     User device  330  may send an inventory estimation request  350  over network  340  to inventory estimation system  310 . Inventory estimation request  350  may include details of item and region for computing target inventory estimation of an item in a region. In some embodiments, inventory estimation request  350  may include details of sets of items related to the requested target inventory estimation item. Inventory estimation request  350  may include other configuration data to configure the behavior of modules of inventory estimation system  310 . For example, inventory estimation request  350  may include a configuration of time interval to update overall demand of item in forecast data  323  and set of related items in segment data  324 . Inventory estimation system  310  upon receiving the inventory estimation request  350  over network begins computation of target inventory estimation of an item in a particular region. 
       FIG.  4    illustrates a schematic diagram of an exemplary server of a distributed system, according to some embodiments of the present disclosure. According to  FIG.  4   , server  410  of distributed computing system  400  comprises a bus  412  or other communication mechanisms for communicating information, one or more processors  416  communicatively coupled with bus  412  for processing information, and one or more main processors  417  communicatively coupled with bus  412  for processing information. Processors  416  can be, for example, one or more microprocessors. In some embodiments, one or more processors  416  comprises processor  465  and processor  466 , and processor  465  and processor  466  are connected via an inter-chip interconnect of an interconnect topology. Main processors  417  can be, for example, central processing units (“CPUs”). 
     Server  410  can transmit data to or communicate with another server  430  through a network  422 . Network  422  can be a local network, an internet service provider, Internet, or any combination thereof. Communication interface  418  of server  410  is connected to network  422 , which can enable communication with server  430 . In addition, server  410  can be coupled via bus  412  to peripheral devices  440 , which comprises displays (e.g., cathode ray tube (CRT), liquid crystal display (LCD), touch screen, etc.) and input devices (e.g., keyboard, mouse, soft keypad, etc.). 
     Server  410  can be implemented using customized hard-wired logic, one or more ASICs or FPGAs, firmware, or program logic that in combination with the server causes server  410  to be a special-purpose machine. 
     Server  410  further comprises storage devices  414 , which may include memory  461  and physical storage  464  (e.g., hard drive, solid-state drive, etc.). Memory  461  may include random access memory (RAM)  462  and read-only memory (ROM)  463 . Storage devices  414  can be communicatively coupled with processors  416  and main processors  417  via bus  412 . Storage devices  414  may include a main memory, which can be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processors  416  and main processors  417 . Such instructions, after being stored in non-transitory storage media accessible to processors  416  and main processors  417 , render server  410  into a special-purpose machine that is customized to perform operations specified in the instructions. The term “non-transitory media” as used herein refers to any non-transitory media storing data or instructions that cause a machine to operate in a specific fashion. Such non-transitory media can comprise non-volatile media or volatile media. Non-transitory media include, for example, optical or magnetic disks, dynamic memory, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a CD-ROM, any other optical data storage medium, any physical medium with patterns of holes, a RAM, a PROM, and an EPROM, a FLASH-EPROM, NVRAM, flash memory, register, cache, any other memory chip or cartridge, and networked versions of the same. 
     Various forms of media can be involved in carrying one or more sequences of one or more instructions to processors  416  or main processors  417  for execution. For example, the instructions can initially be carried out on a magnetic disk or solid-state drive of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to server  410  can receive the data on the telephone line and use an infra-red transmitter to convert the data to an infra-red signal. An infra-red detector can receive the data carried in the infra-red signal, and appropriate circuitry can place the data on bus  412 . Bus  412  carries the data to the main memory within storage devices  414 , from which processors  416  or main processors  417  retrieves and executes the instructions. 
     Inventory estimation system  310  or one or more of its components may reside on either server  410  or  430  and may be executed by processors  416  or  417 . System  100  or one or more of its components may also reside on either server  410  or  430 . In some embodiments, the components of inventory estimation system  310  and/or system  100  may be spread across multiple servers  410  and  430 . For example, inventory estimation system  310  components  311 - 314  may be executed on multiple servers. 
       FIG.  5    illustrates a hierarchical set of geographical regions for inventory management, consistent with the disclosed embodiments. As illustrated in  FIG.  5   , hierarchical set of geographical regions may include an overall region  500  served by system  100 . Overall region  500  may represent all geographical regions from where orders are received by system  100 . 
     Overall region  500  may be served by system  100  for orders received via external front end system  103  (as shown in  FIG.  1   ). Overall region  500  may include sub regions  510  and  520 . Sub regions  510  and  520  may include fulfillment center. In some embodiments, sub regions  510  and  520  may include groupings of fulfillment centers  530  and  540 . Fulfillment center groups  530  and  540  may be grouped by types of service or types of items offered by fulfillment centers part of the group. For example, fulfillment centers  533  and  534  may both offer overnight shipping service. In another instance, fulfillment centers  547  and  548  of group  540  may both ship groceries and have same value for service level. 
     In some embodiments, a fulfillment center may be part of different geographical regions based on the items served by the fulfillment centers. In some embodiments, fulfillment centers groups  530  and  540  may be based on the item whose target item inventory estimation was requested by a user of user device (e.g., user device  340  of  FIG.  1   ). 
     System  100  may divide overall region  500  into sub regions  510  and  520  according to fulfillment capabilities and fulfillment costs to different regions  510  and  520 . In some embodiments, system  100  may divide overall region  500  into sub regions  510  and  520  to uniformly distribute types of services offered by fulfillment centers (e.g., FC  200  of  FIG.  2   ). In some embodiments, sub regions  510  and  520  may be prepared based on number of orders and type of orders requested by a user of system  100 . 
       FIG.  6    is an illustrative flow chart of a method for determining target inventory estimation of an item in a region, consistent with the disclosed embodiments. In some embodiments, the steps of method  600  may be performed by inventory estimation system  310  for purposes of illustration. It will be appreciated that the illustrated method may be altered to modify the order of steps, or further include additional steps. 
     In step  610 , inventory estimation system  310  may retrieve an item identifier associated with an item. Inventory estimation system  310  may retrieve item identifier upon receiving a request (e.g., inventory estimation request  350  of  FIG.  1   ) for target inventory estimation of an item. Inventory estimation system  310  may receive an automated inventory estimation request for each item at regular intervals of time. For example, inventory estimation system  310  may receive an inventory estimation request for an item at the end of the day to recompute any changes to inventory estimation of that item in different geographical regions served by system  100 . 
     In some embodiments, inventory estimation system  310  may receive an inventory estimation request upon system  100  observing a change in orders for the inventory estimation requested item beyond a threshold amount. Inventory estimation system  310  may receive inventory estimation requests for an item when a percentage change of orders for the item in a geographical region is above a threshold amount. Shipment and order tracking system  111  may trigger inventory estimation requests for an item and send to inventory estimation system  310 . System  100  may have triggers for other events to send inventory estimation requests of an item. In some embodiments, inventory estimation system  310  may have the ability to configure inventory estimation trigger events. A user of inventory estimation system  310  may configure the interval and or trigger event for inventory estimation system  310  to retrieve an item identifier in a configuration file (e.g., inventory estimation request  350 ). 
     In some embodiments, inventory estimation system  310  may need to transform the received request to retrieve the item identifier. For example, the transformation of a request may include looking up an item name in item data  321  to retrieve an item identifier. Item identifier may be an alphanumeric string uniquely representing the item. In some embodiments, the transformation may include identifying a new item identifier. For example, the received request may include an item identifier for a discontinued item, and the transformation may provide an identifier of the new version of the item. Inventory estimation system  310  may request forecast module  311  to perform a transformation and/or retrieval of item identifier corresponding to requested target inventory estimation item. 
     In step  620 , inventory estimation system  310  may access the overall demand forecast for an item using the retrieved item identifier. Inventory estimation system  310  may use order data  322  to determine the overall demand forecast of an item. In some embodiments, inventory estimation system  310  may communicate through FMG  115  to determine past order fulfillment of item orders by FC  200  and 3rd party fulfillment centers  121 A-C to forecast overall demand for the item. Inventory estimation system  310  may also communicate with WMS  119  to get live item order fulfillment updates through mobile devices  119  A-C belonging to FC  200 . 
     In step  630 , inventory estimation system  310  may calculate mean and variance estimates of overall demand forecast of the item. Inventory estimation system  310  may review the previously computed overall demand forecast for the item. Inventory estimation system  310  may retrieve the previously determined overall demand forecast for an item from demand data  326 . In some embodiments, inventory estimation system  310  may review order data  322  to compute the mean and variance demand forecast of the item. In some embodiments, inventory estimation system  310  may communicate with shipment and order tracking system  111  to determine mean and variance estimates of the demand forecast of the item. 
     In step  640 , inventory estimation system  310  may evaluate an item&#39;s demand share estimate in the geographical region defined in the item estimation request  350  received in step  610 . Demand share module  313  may review order data  322  associated with fulfillment centers in a geographical region to determine a geographical region&#39;s demand share for an item. 
     Demand share module  313  may determine a share of orders processed by fulfillment centers in a geographical region using order data  322 . Demand share module  313  may consider order data from a defined period to determine the share of orders. In some embodiments, demand share module  313  may determine a share of the item&#39;s orders in a geographical region at regular intervals of time. The time interval may depend on the type of item. For example, a fast-selling item may need share determination at regular intervals, and slow-selling item share determination may occur over a long period of data. In some embodiments, a user may configure the time interval of orders to use to determine demand share. Demand share module  313  may consider seasonal demand when past order data is used to generate demand share estimation. For example, demand share module  313  may review past order data from the same time period of previous years in computing demand share estimation for a particular geographical region. Demand share module  313  may store demand share estimation associated with an item and/or segment of items in data store  320 . 
     In some embodiments, inventory estimation system  310  may determine a set of item identifiers associated with the requested target inventory estimation item&#39;s identifier retrieved in step  610  to generate demand share of the item. Demand share of the item may be generated by generating and combining the demand share estimates of the items associated with the set of identifiers. Demand share estimates of the items associated with the set of identifiers may be combined by computing average or mean of the demand share estimate values. Demand share estimates of the items associated with the set of item identifiers may be computed upon failure to directly compute the demand share estimate of the item associated with the item identifier in step  610 . Demand share module  313  may fail to compute the demand share estimate of the item directly if there is very little data for the item. For example, a new item may not have enough sale orders to use it to determine demand share in a geographical region. In another instance, a slow selling or expensive item may not generate enough sale orders to determine demand share estimate directly for the item. In some embodiments, demand share estimates of the items associated with the set of identifiers is aggregated and adjusted to the number of orders of the item associated with the item identifier in step  610 . 
     A set of item identifiers associated with an item may represent an item segment. An Identified segment may include items related to the item identified in step  610 . Item segments may be pre-defined and stored in segment data  324  of data store  320 . Segment data  324  may be updated at regular intervals or may be requested as part of the item inventory estimation request (e.g., inventory estimation request  350 ) received in step  610 . 
     Item segment data may be determined based on the similarity of items. Item similarity may be determined using the statically assigned labels of an item. A segment of items may have a set of common labels between the items in the segment. For example, books of various genres may all be meant for children and may include a common children book label and may be considered together as a segment of items. In some embodiments, segment data may be determined dynamically based on order data. For example, items purchased together and/or having the same labels may be considered part of the same segment. In some embodiments, the rules for determining segment data may be configurable as part of an inventory estimation request. A user may provide segmentation configuration rules as part of inventory estimation request  350 . Upon determination of segmentation rules, demand share module  312  may determine the share of the total orders of a set of items belonging to a segment in a particular geographical region. 
     In step  650 , inventory estimation system  310  may calculate mean and variance of demand share of item in geographical region determined in step  640 . Inventory estimation system  310  may calculate mean and variance of demand share of item in a geographical region by combining mean and variance estimates of the overall demand forecast of the item with the demand share of the item in the geographical region. 
     In step  660 , inventory estimation system  310  may determine the service level associated with the geographical region of the item associated with the item identifier determined in step  610 . Inventory estimation system  610  may determine service level requirements from a received request for target inventory estimation (e.g., inventory estimation request  350 ). 
     Service level requirements may be related to fraction of orders of an item satisfied by a geographical region. For example, service level of a geographical region may require a certain fraction of item orders of the total item order to be fulfilled by fulfillment centers in that geographical region. In some embodiments, service level of a geographical region may be based on number of orders of the orders directed to fulfillment centers (e.g., 3rd party fulfillment centers  121 A-C) in the geographical region are met and shipped from those fulfillment centers. In some embodiments, service level requirements are based on the stock rate of the item identified in step  610 . A detailed description of service levels configuration and computation can be found in  FIG.  3    description of service level data  328  above. 
     In step  670 , Inventory estimation system  310  may generate target inventory estimation of the item associated. Inventory estimation system  310  may be generated by combining mean and variance estimates of the item calculated in step  630  with the demand share estimate of the item in the geographical region determined in step  640 . In some embodiments, mean and variance estimates of demand share of the item in the geographical reason is also included in the combination to generate the target inventory estimation of the item. The target inventory value, based on mean and variance estimates of demand, may be set equal to the mean demana plus 
     
       
         
           
             
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     times the standard deviation of the demand, where c is the coefficient of variation of the demand, and b is the desired service level. This method is based on an extension to the Vysochanskij-Petunin inequality (Vysochanskij and Petunin  1980 ). If the probability distribution of the demand for an item has a unimodal distribution, the Vysochanskij and Petunin inequality gives a bound on the probability that the demand exceeds a given target value. Here we extend that result to obtain a bound on the expectation of the lost demand, i.e. the expected value of the overshoot over a certain target: it can be shown that if the demand distribution is nonnegative and unimodal, and the inventory target is set as in the formula above, then the average fraction of the demand lost is no larger than (1-b). 
     In step  680 , inventory estimation system  310  may respond to the received item identifier with the generated target inventory estimation in step  670 . Inventory estimation system  310  may respond over network  340 . Inventory estimation system  310 , upon completion of step  680 , completes (step  699 ) executing method  600  on distributed computing system  400 . 
       FIG.  7    is an illustrative flow chart of a method for determining target inventory estimation of an item at multiple geographical regions offering different services, consistent with the disclosed embodiments. In some embodiments, the steps of method  700  may be performed by inventory estimation system  310  for purposes of illustration. It will be appreciated that the illustrated method may be altered to modify the order of steps, or further include additional steps. 
     In step  710 , inventory estimation system  310  may generate target inventory estimation of an item in first set of geographical regions. Inventory estimation system  310  may employ method  600  described in  FIG.  6    description above to compute the target inventory estimation of each geographical region of the first set of geographical regions. The first set of geographical regions (e.g., sub region  510  of  FIG.  5    with fulfillment centers  511 ,  512 ,  533 , and  534 ) may be selected from sets of geographical regions (e.g., sub regions  510  and  520 ) covering all the area (e.g., overall region  500 ) served by system  100  to satisfy, ship and track item orders. Inventory estimation system  310  may determine first set of geographical regions which share a common first service type. Inventory estimation system  310  may represent the first set of geographical regions sharing first service type as a group, such as fulfillment center groups  530  and  540 . Inventory estimation system  100  may select the first set of geographical regions that are part of the geographical region associated with the item estimation request (e.g., item estimation request  350  of  FIG.  3   ). 
     In step  720 , inventory estimation system  310  may aggregate a second set of geographical regions associated with second service type that form part of the geographical region associated with the item estimation request. The second set of regions are regions which do not form a group such as first set of geographical regions. For example, an inventory estimation request for sub region  510  may include fulfillment center group  530  with fulfillment centers  533  and  534  acting as first set of geographical regions and the fulfillment centers  511  and  512  acting as second set of geographical regions. The second set of geographical regions may include one or more different service types offered by their fulfillment centers and do not form a group. In some embodiments, the lack of grouping may be based on the type of item for which target inventory estimation is requested. For example, a target inventory estimation request for fresh meat may need geographical regions with cold storage facility. In another instance, a target inventory estimation request for fresh produce may need regions with overnight shipping capability. Inventory estimation system  310  may aggregate second set of geographical regions as a group temporarily for a certain type of item for which target inventory estimation was requested. 
     In step  730 , inventory estimation  310  may generate target inventory estimation for combined demand for first and second types of service offered by first set and second set of geographical regions respectively. Inventory estimation  310  may determine the target inventory estimations of each geographical region in the second set of geographical regions before combining them with target inventory estimation of the first geographical region. Inventory estimation system  310  may combine target inventory estimations of first and second set of regions by adding the target inventory estimation values of the two sets of regions. In some embodiments, inventory estimation system  310  may need to adjust the combined value of target inventory estimation to satisfy service level of the combined geographical region of first and second set of geographical regions. For example, the service level requirements of the combined first and second set of geographical regions may be lower than the individual service levels of first and second set of regions and thus a lower target inventory estimation value would meet the combined region service level requirements. 
     In step  740 , inventory estimation system  310  may respond to received item identifier with generated target inventory estimation for combined target inventory estimation for first and second service type as served by first and second set of geographical regions. Inventory estimation system  310 , upon completion of step  740 , completes (step  799 ) executing method  700  on distributed computing system  400 . 
     While the present disclosure has been shown and described with reference to particular embodiments thereof, it will be understood that the present disclosure can be practiced, without modification, in other environments. The foregoing description has been presented for purposes of illustration. It is not exhaustive and is not limited to the precise forms or embodiments disclosed. Modifications and adaptations will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed embodiments. Additionally, although aspects of the disclosed embodiments are described as being stored in memory, one skilled in the art will appreciate that these aspects can also be stored on other types of computer readable media, such as secondary storage devices, for example, hard disks or CD ROM, or other forms of RAM or ROM, USB media, DVD, Blu-ray, or other optical drive media. 
     Computer programs based on the written description and disclosed methods are within the skill of an experienced developer. Various programs or program modules can be created using any of the techniques known to one skilled in the art or can be designed in connection with existing software. For example, program sections or program modules can be designed in or by means of .Net Framework, .Net Compact Framework (and related languages, such as Visual Basic, C, etc.), Java, C++, Objective-C, HTML, HTML/AJAX combinations, XML, or HTML with included Java applets. 
     Moreover, while illustrative embodiments have been described herein, the scope of any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those skilled in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application. The examples are to be construed as non-exclusive. Furthermore, the steps of the disclosed methods may be modified in any manner, including by reordering steps and/or inserting or deleting steps. It is intended, therefore, that the specification and examples be considered as illustrative only, with a true scope and spirit being indicated by the following claims and their full scope of equivalents.