## 2 State of the Art
Concerning a set of other parameters associated with the RFID reading and identification process and the performance statistics of this traceability system, which are also relevant in this context, there is a parameter \(Q\) which briefly specifies the number of RFID tags to be present in the reading field of the signal pick-up antenna to be considered in the RFID reader and, in turn, which of these tags should be detected in the process [23]. In this sense, the value of \(Q\) is communicated to the tags by the RFID reader, where in turn each of these tags selects a random communication slot from \(x\) for its response. For the tracking and inventory process to be carried out as quickly and efficiently as possible, as many of the \(x\) communication slots as possible must be occupied by the RFID tags, but without multiple occupations of these slots, which would lead to collisions in the context of data transmission between the interconnected RFID components in the AIDC system [24]. In turn, if the reader detects that the value assigned to \(Q\) is too large (where hardly any communication windows are occupied) or too small (where unwanted collisions occur), it should be automatically adjusted and loaded onto the tags (with a range of values for \(Q\) from 0 to 15, by definition). Since this type of adjustment can be time-consuming and possibly inconvenient in terms of tracking activity, the reader with this configuration parameter must be properly configured and informed of the approximate number of RFID tags expected to go through the antenna-field-reading process. In this way, setting the right value for the number of communication windows right from the start of the traceability process proves to be the ideal scenario [25]. As for another parameter corresponding to the session, tags have an electronic product code (EFC), a standard created to facilitate the unique identification of products and objects worldwide, based on RFID technology (and aimed at improving efficiency and visibility in the context of the production chain), of the EPCGlobal Class 1 Gen 2 type. In the context of the radio-frequency reading system, they support four different sessions, considering that in each session a respective inventory flag can be assigned to an RFID tag to indicate whether that tag has already been detected by the reader as part of an asset-tracking and inventory process. These inventory-level flags have different properties depending on each session, something that allows for the recognition of a long persistence time interval associated with each of these sessions [26]. The data captured by RFID has several characteristics that fit into the concept of big data, which is increasingly prevalent in the panorama of information and data in large quantities that industries must consider and manage today. On the one hand, the volume of data generated will become enormous as production activities are carried out in the context of a smart factory with RFID integration, commonly reaching hundreds of RFID data points. On the other hand, RFID data in its presentation through the EPC code is often very abstract information, when considering the use of a hexadecimal format (numbering system with 16 symbols or possible digit values from 0 to 9, followed by six alphabetic characters, assuming only letters from A through F). This presentation of product data information, which is intended to be subsequently interpreted in the most optimal way possible for decision-making in production, makes the response information in the format not ideal for the needs and objectives of management activity at the industrial level. In addition, RFID data are almost always interconnected with other production-related information, including technical drawings, production orders, and purchase orders, which are difficult to process using other types of approaches that are not adapted to managing data in massive quantities [27].