The plummeting cost of Bluetooth tags and the ubiquity of mobile devices are revolutionizing the traditional lost-and-found service. This paper presents SecureFind, a secure and privacy-preserving object-finding system via mobile crowdsourcing. In SecureFind, a unique Bluetooth tag is attached to every valuable object, and the owner of a lost object submits an object-finding request to many mobile users via the SecureFind service provider. Each mobile user involved searches his vicinity for the lost object on behalf of the object owner who can infer the location of his lost object based on the responses from mobile users. SecureFind is designed to ensure strong object security such that only the object owner can discover the location of his lost object as well as offering strong location privacy to mobile users involved. The high efficacy and efficiency of SecureFind are confirmed by extensive simulations.
Recent years have witnessed significant research on missing-tag detection @cite_31 @cite_43 @cite_2 @cite_27 @cite_47 @cite_19 @cite_29 @cite_39 @cite_40 and identification @cite_21 @cite_42 @cite_34 in RFID systems. This line of work aims to quickly detect whether or which tags are missing in a large RFID system, while SecureFind targets a totally different problem. In particular, a lost tag in SecureFind is a tag lost by its owner but still in the SecureFind service provider's service region, and SecureFind aims to determine which mobile detector has the lost tag in his coverage in order to locate and retrieve the lost object without revealing such information to either the mobile detector or service provider. In contrast, a missing tag in @cite_31 @cite_43 @cite_2 @cite_27 @cite_47 @cite_19 @cite_29 @cite_39 @cite_40 @cite_21 @cite_42 @cite_34 means a tag taken away from the monitored area, and the goal there is to determine if any tag is missing. Therefore, existing missing-tag detection schemes are inapplicable to our problem.
@cite_47 @cite_29 @cite_21 @cite_42 @cite_39 @cite_43 @cite_27 @cite_19 @cite_40 @cite_2 @cite_31 @cite_34
2128935842 2102471667 2000922528 2101201152 2149197043 2059996234 2164690908
As RFID tags become more widespread, new approaches for managing larger numbers of RFID tags will be needed. In this paper, we consider the problem of how to accurately and efficiently monitor a set of RFID tags for missing tags. Our approach accurately monitors a set of tags without collecting IDs from them. It differs from traditional research which focuses on faster ways for collecting IDs from every tag. We present two monitoring protocols, one designed for a trusted reader and another for an untrusted reader. Comparing with the classical barcode system, RFID extends the operational distance from inches to a number of feet (passive RFID tags) or even hundreds of feet (active RFID tags). Their wireless transmission, processing and storage capabilities enable them to support the full automation of many inventory management functions in the industry. This paper studies the practically important problem of monitoring a large set of RFID tags and identifying the missing ones - the objects that the missing tags are associated with are likely to be missing, too. This monitoring function may need to be executed frequently and therefore should be made efficient in terms of execution time, in order to avoid disruption of normal inventory operations. Based on probabilistic methods, we design a series of missing-tag identification protocols that employ novel techniques to reduce the execution time. Our best protocol reduces the time for detecting the missing tags by 88.9 or more, when comparing with existing protocols. Radio frequency identification (RFID) technologies are poised to revolutionize retail, warehouse, and supply chain management. One of their interesting applications is to automatically detect missing tags in a large storage space, which may have to be performed frequently to catch any missing event such as theft in time. Because RFID systems typically work under low-rate channels, past research has focused on reducing execution time of a detection protocol to prevent excessively long protocol execution from interfering normal inventory operations. However, when active tags are used for a large spatial coverage, energy efficiency becomes critical in prolonging the lifetime of these battery-powered tags. Furthermore, much of the existing literature assumes that the channel between a reader and tags is reliable, which is not always true in reality because of noise interference in the environment. Given these concerns, this paper makes three contributions. First, we propose a novel protocol design that considers both energy efficiency and time efficiency. It achieves multifold reduction in both energy cost and execution time when compared to the best existing work. Second, we reveal a fundamental energy-time tradeoff in missing-tag detection, which can be flexibly controlled through a couple of system parameters in order to achieve desirable performance. Third, we extend our protocol design to consider channel error under two different models. We find that energy time cost will be higher in unreliable channel conditions, but the energy-time tradeoff relation persists. Tag identification is an important tool in RFID systems with applications for monitoring and tracking. A RFID reader recognizes tags through communication over a shared wireless channel. When multiple tags simultaneously transmit their IDs to a reader, the tag signals collide and this collision disturbs the reader's identification process. Therefore, tag collision arbitration for passive RFID tags is a significant issue for fast identification. This paper presents two adaptive tag anti-collision protocols, an Adaptive Query Splitting protocol (AQS), which is an improvement on the query tree protocol and an Adaptive Binary Splitting protocol (ABS), which is based on the binary tree protocol, which is a de facto standard for RFID anti-collision protocols. To reduce collisions and identify tags efficiently, adaptive splitting protocols use information obtained from the last process of tag identification. Our performance evaluation shows that AQS and ABS outperform other tree based tag anti-collision protocols. As RFID tags become more widespread, new approaches for managing larger numbers of RFID tags will be needed. In this paper, we consider the problem of how to accurately and efficiently monitor a set of RFID tags for missing tags. Our approach accurately monitors a set of tags without collecting IDs from them. It differs from traditional research which focuses on faster ways for collecting IDs from every tag. We present two monitoring protocols, one designed for a trusted reader and the other for an untrusted reader. RFID (radio frequency identification) technologies are poised to revolutionize retail, warehouse and supply chain management. One of their interesting applications is to automatically detect missing tags (and the associated objects) in a large storage space. In order to timely catch any missing event such as theft, the detection operation may have to be performed frequently. Because RFID systems typically work under low-rate channels, past research has focused on reducing execution time of a detection protocol, in order to prevent excessively-long protocol execution from interfering normal inventory operations. However, when active tags are used to provide a large spatial coverage, energy efficiency becomes critical in prolonging the lifetime of these battery-powered tags. Existing literature lacks thorough study on how to conserve energy in the process of missing-tag detection and how to jointly optimize energy efficiency and time efficiency. This paper makes two important contributions: First, we propose a novel protocol design that takes both energy efficiency and time efficiency into consideration. It achieves multi-fold reduction in both energy cost and execution time when comparing with the best existing work. In some cases, the reduction is more than an order of magnitude. Second, we reveal a fundamental energy-time tradeoff in missing-tag detection. Through our analytical framework, we are able to flexibly control the tradeoff through a couple of system parameters in order to achieve desirable performance. The tree search (or splitting) method introduced by Capetanakis (1979) for use in conventional multiaccess systems can also be applied to radiofrequency identification systems arbitration. This paper performs a transient analysis of this, and related methods.