Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> The network architecture of an RFID system affects the operating performance and scalability of the entire system. The related researches about RFID system could be made easier as the bridge-based and the gateway-based network architecture. This study considers a scenario for an RFID object tracking system designs a hierarchical RFID network system and evaluates the operating performance of different RFID system architectures. The results of performance evaluations demonstrate that the proposed hierarchical RFID network architecture reduces the network and database system loading by 41.8% and 83.2%, respectively. The operation of RFID object tracking over the hierarchical network architecture is indicated to be highly efficient and scalable. <s> BIB001 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> With the increased popularity of RFID applications, different authentication schemes have been proposed to provide security and privacy protection for users. Most recent RFID protocols use a central database to store the RFID tag data. The RFID reader first queries the RFID tag and returns the reply to the database. After authentication, the database returns the tag data to the reader. In this paper, we propose a more flexible authentication protocol that provides comparable protection without the need for a central database. We also suggest a protocol for secure search for RFID tags. We believe that as RFID applications become widespread, the ability to securely search for RFID tags will be increasingly useful. <s> BIB002 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> Privacy-Preserving Authentication (PPA) is crucial for Radio Frequency Identifcation (RFID)-enabled applications. Without appropriate formal privacy models, it is difficult for existing PPA schemes to explicitly prove their privacy. Even worse, RFID systems cannot discover potential security flaws that are vulnerable to new attacking patterns. Recently, researchers propose a formal model, termed as Strong Privacy, which strictly requires tags randomly generate their output. Adopting the Strong Privacy model, PPA schemes have to employ brute-force search in tags' authentications, which incurs unacceptable overhead and delay to large-scale RFID systems. Instead of adopting Strong Privacy, most PPA schemes improve the authentication efficiency at the cost of the privacy degradation. Due to the lack of proper formal models, it cannot be theoretically proven that the degraded PPA schemes can achieve acceptable privacy in practical RFID systems. To address these issues, we propose a weak privacy model, Refresh, for designing PPA schemes with high efficiency as well as acceptable privacy. Based on Refresh, we show that many well-known PPA schemes do not provide satisfied privacy protection, even though they achieve relatively high authentication efficiency. We further propose a Light-weight privAcy-preServing authenTication scheme, LAST, which can guarantee the privacy based on the Refresh model and realize O(1) authentication efficiency, simultaneously. <s> BIB003 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> Cardinality estimation and tag authentication are two major issues in large-scale Radio Frequency Identification (RFID) systems. While there exist both per-tag and probabilistic approaches for the cardinality estimation, the RFID-oriented authentication protocols are mainly per-tag based: the reader authenticates one tag at each time. For a batch of tags, current RFID systems have to identify them and then authenticate each tag sequentially, incurring large volume of authentication data and huge communication cost. We study the RFID batch authentication issue and propose the first probabilistic approach, termed as Single Echo based Batch Authentication (SEBA), to meet the requirement of prompt and reliable batch authentications in large scale RFID applications, e.g., the anti-counterfeiting solution. Without the need of identifying tags, SEBA provides a provable probabilistic guarantee that the percentage of potential counterfeit products is under the user-defined threshold. The experimental result demonstrates the effectiveness of SEBA in fast batch authentications and significant improvement compared to existing approaches. <s> BIB004 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> Environmental effects may seriously threaten the performance of UHF RFID systems and reduce the rate of successful reading; many applications aiming at the so-called item-level tagging (ILT) can be therefore compromised. In order to preserve the reliability of the tag acquisition the so-called near field (NF) UHF RFID has been recently considered. In this paper, the main properties and the performance of NF UHF RFID systems are investigated by means of electromagnetic analyses based on both theoretical evaluations on simple but representative radiating elements and measurements carried out also on real UHF RFID devices. <s> BIB005 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> A broadband segmented loop antenna is presented for ultra high frequency (UHF) near-field radio frequency identification (RFID) applications. Using a segmented line, the current distribution along the loop is kept in phase even though the perimeter of the loop is more than two operating wavelengths so that the proposed antenna generates strong and even magnetic field distribution in the near-field zone of the antenna. The antenna prototype, printed onto a piece of FR4 substrate, with an overall size of , achieves a large interrogation zone of with good impedance matching and uniform magnetic field distribution over the entire UHF RFID band of 840-960 MHz. <s> BIB006 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> RFID (radio-frequency identification) is an emerging technology with extensive applications such as transportation and logistics, object tracking, and inventory management. How to quickly identify the missing RFID tags and thus their associated objects is a practically important problem in many large-scale RFID systems. This paper presents three novel methods to quickly identify the missing tags in a large-scale RFID system of thousands of tags. Our protocols can reduce the time for identifying all the missing tags by up to 75% in comparison to the state of art. <s> BIB007 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> Radio Frequency IDentification (RFID) has attracted considerable attention in recent years for its low cost, general availability, and location sensing functionality. Most existing schemes require the tracked persons to be labeled with RFID tags. This requirement may not be satisfied for some activity sensing applications due to privacy and security concerns and uncertainty of objects to be monitored, e.g., group behavior monitoring in warehouses with privacy limitations, and abnormal customers in banks. In this paper, we propose TASA-Tag-free Activity Sensing using RFID tag Arrays for location sensing and frequent route detection. TASA relaxes the monitored objects from attaching RFID tags, online recovers and checks frequent trajectories by capturing the Received Signal Strength Indicator (RSSI) series for passive RFID tag arrays where objects traverse. In order to improve the accuracy for estimated trajectories and accelerate location sensing, TASA introduces reference tags with known positions. With the readings from reference tags, TASA can locate objects more accurately. Extensive experiment shows that TASA is an effective approach for certain activity sensing applications. <s> BIB008 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> A metal-plate backed metamaterial-inspired loop antenna is proposed for both near-field and far-field radio frequency identification (RFID) applications at ultra high frequency (UHF). The antenna is composed of a distributed capacitor loaded segmented loop and a backed metallic plate. The antenna prototype printed onto an FR4 printed circuit board (PCB) with an overall size of 250 mm × 250 mm × 25 mm shows desirable performance for both near-field and far-field applications over the frequency range of 900–960 MHz. Hence, it is very promising for UHF RFID reader applications. <s> BIB009 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> A robust estimation procedure for sensing the locations of passive UHF radio frequency identification (RFID) tags is introduced based on spatial deployment of the reader antennas for maximum signal diversity. A signal model is developed for the received signal strength indicator seen by each reader antenna and incorporated into a mean-square error testing function. The error function is minimized at each test point in the interrogation zone to find the point with the minimum mean-square error. The minimization is independent of the tag type and orientation, making the proposed method very robust compared with other methods that are based on reference tags and radio maps. Experimental results are presented for a realistic retail scenario with multiple tagged items achieving an estimation accuracy of 35 cm. The location sensing system uses conventional UHF RFID readers, antennas, and passive tags, providing additional capability to existing item-level RFID systems. This added value will help to offset the high cost of large-scale RFID infrastructure development. <s> BIB010 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> This paper provides an overview of the Internet of Things (IoT) with emphasis on enabling technologies, protocols, and application issues. The IoT is enabled by the latest developments in RFID, smart sensors, communication technologies, and Internet protocols. The basic premise is to have smart sensors collaborate directly without human involvement to deliver a new class of applications. The current revolution in Internet, mobile, and machine-to-machine (M2M) technologies can be seen as the first phase of the IoT. In the coming years, the IoT is expected to bridge diverse technologies to enable new applications by connecting physical objects together in support of intelligent decision making. This paper starts by providing a horizontal overview of the IoT. Then, we give an overview of some technical details that pertain to the IoT enabling technologies, protocols, and applications. Compared to other survey papers in the field, our objective is to provide a more thorough summary of the most relevant protocols and application issues to enable researchers and application developers to get up to speed quickly on how the different protocols fit together to deliver desired functionalities without having to go through RFCs and the standards specifications. We also provide an overview of some of the key IoT challenges presented in the recent literature and provide a summary of related research work. Moreover, we explore the relation between the IoT and other emerging technologies including big data analytics and cloud and fog computing. We also present the need for better horizontal integration among IoT services. Finally, we present detailed service use-cases to illustrate how the different protocols presented in the paper fit together to deliver desired IoT services. <s> BIB011 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> The Voice over Internet Protocol (VoIP) was developed for making telephone calls using an Internet connection instead of a regular (or analog) phone line. However, traditional VoIP technologies have many disadvantages: user mobility is limited, and the need for Internet access makes it impossible to dial or receive data anytime from anywhere. Sensor technology has been integrated with VoIP to make mobility possible. However, maintaining communication quality while a VoIP account switches to the new IP address is difficult. Thus, this work proposes a Radio Frequency Identification (RFID)-based seamless personal communication system with cloud computing. The proposed system has two main technologies: RFID and Session Initiation Protocol (SIP). First, RFID senses and recognizes mobile devices carried by users. Finally, SIP establishes and maintains VoIP calling. <s> BIB012 </s> Smart Solutions for RFID based Inventory Management Systems: A Survey <s> IoT in Inventory Management. <s> This research aims to find the best practice of logistic management for Electricity Generation Authority of Thailand (EGAT) Mae Mao Mining, Lampang. This research applied the use of RFID for lignite coal trucks and data from RFID proceed through a server and was stored into a private cloud computing. The equipment and tools used in research was a RFID reader, UHF passive RFID tags, Arduino Mega 2560 + Ethernet Shield, PHP, Jason, Node.JS and Maria DB as a database system. The protocol used was MQTT. 27 trucks had UHF passive tags installed, 1 crusher (location number 3) had an RFID reader installed. This system has been operating 24 hours a day 7 days a week, from the beginning of 2015 to mid 2016. The results of the research show that officers who worked for related systems were satisfied. The system enhanced the best practice of lignite coal mining logistic in terms of information checking. <s> BIB013
IoT is creating a new operation environment where each physical asset is individually identified with an ID, intelligently connected into a network, and digitally visible to the whole supply chain at a by-unit level and in real time  . IoT underlies almost all the emerging technologies used today. Mobile phones are the most prevalent example of popular technology. Driverless cars, is another application of this technology, which works through interconnectivity between the road, online maps, and other connected data, including weather predictions and traffic reports  . The BodyGuardian is a wearable sensor system that can remotely read a patient's biometrics (electrocardiogram, heart rate, respiration rate and activity level), sending data to the patient's physician and allowing users to go about their daily lives outside of a clinic facility BIB011  . Similarly, by linking machines, products, people, and supply chain members, IoT provides a new environment for supply chain managers to manage and control inventory resources using applications that run on middleware servers  . The feasibility and flexibility of the architecture of this supply chain was proposed through a detailed implementation that uses wireless sensor networks and web services to introduce the use of the smart object framework, these networks encapsulate RFID, sensor technologies, embedded object logic, object ad-hoc networking, and internet-based information infrastructure to realize the real-time monitoring of the flow of goods through a supply chain  . The implementation of RFID in the supply chain was employed to achieve real-time inventory monitoring and information sharing, such approach can help the system attain high environmental and economic benefits  . The network of inventory objects is shown in Figure 2 .1. By attaching an RFID tag to every item in the inventory, the tagged object becomes part of the network. The inventory administrator uses the handheld RFID readers to scan the objects, handheld readers nowadays can be wireless and smart with processing capabilities, they are connected to the middleware using any of the various computer cables or wireless using Wifi communication protocol IEEE 802.11. The reading distance between the reader and the tags cannot exceed a few centimetres, and both ends must be held appropriately to achieve the required polarization angle. The cloud is serving as the middleware provider for the management system. RFID and associated technology extensive use of in several applications, including educational, transportation, animal tracking, inventory object tracking, and several industrial applications. This have made it recognized as a standard for IoT applications. Two main reasons contributed in this standardization, the increasing demand on this technology and the availability of RFID tags at very low prices. As a result, the cycle of manufacturing RFID-related products has speeded up lately  . 2.2. Cloud Systems in Inventory Management. Cloud computing is a shared IT infrastructure where computing resources are scattered but linked together through the Internet into a large pool of computing resources and that could automatically adjust the allocation of computing resources as the need for computing service fluctuates   . This results in a model for provisioning processes, applications and services that is potentially cost-efficient. In addition, it can make IT management simpler and increase business responsiveness as well  . The evolution of Cloud Computing concept has been driven by the accelerated shift in the computing paradigm in the past half century. Initially, computing power existed mainly in mainframes shared by users using terminals. Standalone personal computers had their share of this revolution, they came powerful enough to process the users' tasks. This has encouraged another phase of this evolution. Users having powerful computers can now exchange information, and share processing power using computer networks. The next phase of the evolution is the internet, a network of local networks connected to form a more global network to utilise remote applications and resources. Finally, the concept of distributed systems came along, which is an computerized grid that facilitates sharing the computing power and storage across the network components. This forms the backbone of cloud computing, as cloud enables utilization of the available resources in a scalable and simple form  , unlike a mainframe is a physical machine that offers finite computing power. Unlike mainframe, a cloud represents all possible resources on the Internet, offering infinite power and capacity. Cloud computing applies distributed arithmetic techniques, which allows developers to more easily develop application services. It can automatically manage large numbers of computers for task and storage distribution. In 2003, the NSF invested USD 8.3 million to support the network virtualization and cloud computing VGrADS, was launched by the top U.S. seven colleges, which was when the research on cloud computing was born BIB013 BIB012 . Cloud plays a key role in RFID identification process through: • Managing the hardware resources in the RFID network efficiently, RFID readers, antennas, and tags. • Managing the information flow from/to the inventory repository regardless of the type of the database engine or the platform used. • Running the inventory management software, and provide the users with a platform-independent, stable, and robust real-time management software. The user must interactively be able to access the management system, add, modify or delete inventory resources, and the changes must take effect instantaneously. Cloud computing is organized into three standard service models  , see Figure 2 .2: • Infrastructure as a Service (IaaS): The cloud vendor provides the servers (such as processing capability), storage (such as replication, backup, and archiving), and connectivity domains (such as firewalls and load balancing). • Platform as a Service (PaaS): Describes a model in which the cloud vendor provides the platform that allows creation and deployment of applications and services the organization accesses through the Internet. • Software as a Service (SaaS): The cloud vendor has complete control over the application, including capabilities, updates, and maintenance. The user is provided with a secure and versatile service accessible via the internet. 3. RFID Principles and Categories. RFID can be used to locate and track items in warehouses and during the entire shipping route as well  . Furthermore, RFID has extensive applications such as transportation and logistics, asset tracking, inventory management, and healthcare BIB007 , object identification and tracking BIB008 , security in airports, malls and military bases BIB003 BIB002  BIB004 BIB008 BIB007 , and so many others. In this article, an overview of the RFID technology and its history is first provided, then RFID types and architectures are explained. In addition, the article analyzes the latest developments of RFID infrastructure and middleware architectures, starting from passive RFID Tags, RFID Antennas, RFID middleware, and the RFID Reader. Finally collision, and anti-collision algorithms in RFID will be explained. RFID networks can be divided into three main categories based on the tag types: Passive RFID, active RFID, and semi-passive RFID Tags. All three types contain integrated circuit that store tag information  . Passive tags are called passive because of the lack of power source, they depend on the energy transmitted from the reader antenna radio frequency signal to power up the tag. On the other hand, active tags contain a small battery that provides the integrated circuit with the power required to operate the tag circuitry, which is why active tags have better coverage, enhanced storage capacity, and they are often programmable. While passive tags on the other hand, have smaller read range, less memory capacity and they are usually programmed once    . Passive UHF RFID is being widely used in order to identify and track several types of inventory items as illustrated in Figure 3 .1. Before moving to the technical aspects, one technical term that is tightly bound to RFID needs to be explained, which is Load Modulation. For the antenna to transfer data, a basic system of modulation resistance, in parallel with the tag antenna is switched on and off at a rate governed by the signal data, the receiver on the other side will need to strip out the carrier signal BIB010 . The tag's antenna captures energy from the transmitted signal, and transfers the modulated signal which contains the tag ID. The receiver circuit is often called transceiver, it is responsible of managing the tag's power in general. In other words, it captures the energy received by the tag's antenna, and release it to feed the tag components. The receiver circuit has gained a considerable amount of research during the recent years  BIB001 . The memory chip contains a preprogrammed unique Identifier   .  RFID tags are usually classified based on the ElectroMagnetic (EM) wave that is used to transfer the signal. The first category is Near-Field, which depends on the direct magnetic induction of the transmitted signal. The second type is Far-Field, which depends on capturing the energy release from the electromagnetic wave, which is a result of the transmitted radio wave from the antenna. The principle of the communication protocol in both techniques is similar. Both of them utilize the electromagnetic field attached to the RF signal to transfer information, the power transferred normally varies between 10 mW and 1 mW  . Far-field is generally used in applications where a long read range is needed. Near-field RFID is generally used to track tags in areas contain metallic barriers BIB005 BIB009  . Inductive coupling technique is preferred in most near-field RFID applications mainly for one reason, the flexibility of using the load modulation techniques to transfer signals between the tag and the antenna and vice versa BIB006 . On the other hand, the electromagnetic field in far-field is radiative in Coupling captures EM energy at a tag's antenna as a voltage disturbance. Part of the energy reaches a tag's antenna is reflected back due to an impedance mismatch between the antenna and the load circuit. The amount of reflected energy vary depending on the impedance of the antenna. This is called Backscattering  . The Table 3 .1 clarifies the characteristics of Near-field versus Far-field and their usage. 3.1. Near Field RFID. Near-Field is a technology where magnetic coupling is used for communication between the reader and tag. In this technology, the modulated RF signal is transmitted through magnetic induction, where the reader passes an AC current through a coil inside the reader, which generates a corresponding alternating magnetic field. A capacitor is used to rectify this voltage, a reservoir of charge accumulates, which is enough to power the tag chip  .  Near-field coupling tags use low carrier frequencies. The two most commonly used are 128 kHz and 13.56 MHz. For instance, the maximum read distances are 372m for 128 kHz and 3.5m for 13.56 MHz. The disadvantages of using low frequencies in near-field are   : • To capture the RF signal, an antenna with a large coil is needed, as the power generated from the antenna is very low. • The radiated power decreases heavily as distance increases. • A low data rate resulted from the low bandwidth used. Due to its design simplicity, Near-Field system was one of the first RFID techniques to be used for the implementation of RFID tags, in particular, passive ones. This technology, however, suffers from physical limitations due to the need of very close contact between the tag and the antenna in order to produce coupling. The range of magnetic induction that can be used is highly dependent on the tag's frequency. As the frequency of operation increases, the distance over which near-field coupling can operate decreases. The energy available for induction is another limitation as a function of distance from the reader coil. As distance increases, the magnetic field drops off at a factor, which can be calculated in the equation  BIB007 : F is the drop factor, and r is the distance between the antenna and the tag. Since applications require maintaining a fixed read rate, tags with with various polarization poles must be detectable, as a result, more tag requirements have arouse, for instance higher read rate and higher radio frequency. These requirements have resulted in using far-field in passive RFID identification  . Power path transmission loss in near field is defined in literature as: where P r is the received power, K is constant that depends on antenna gain and wavelength, P t is the transmitted power. In addition, for near field α can be considered as: 2 < α < 4. The read range for near-field coupling is narrow.The conventional solid-line loop antennas with one operating wavelength can produce uneven magnetic field over the interrogation area, since phase-inversion occurs across the loop conduction material, and therefore the electrical current reaches zero as it passes the antenna material. The reliability of RFID tag detection depends on the strength of the magnetic field. Hence, the relatively weak field in far end regions of the interrogation zone results in degradation of the detection reliability. As a result, the reader antenna must be redesigned to accommodate a larger antenna in order to maximize the coverage area. For instance, a tag antenna of size 150 × 150 mm 2 can compensate the shortage in the read distance.  BIB007 .