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A Bit-Tracking Knowledge-Based query tree for RFID Tag Identification in IoT Systems

SENSORS 2022年第9期22卷 3323页

作者： Lai, Yuan-Cheng Chen, Shan-Yung Hailemariam, Zelalem Legese Lin, Chih-Chung Natl Taiwan Univ Sci & Technol Dept Informat Management Taipei 106 Taiwan Lunghwa Univ Sci & Technol Dept Comp Informat & Network Engn Taoyuan 333 Taiwan

In an IoT (Internet of Things) system where each IoT device has one/many RFID tags, there might be many RFID tags. However, when multiple tags respond to the reader's interrogation at the same time, their signals collide. Due to the collision, the reader must request the colliding tags to retransmit their IDs, resulting in higher communication overhead and longer identification time. Therefore, this paper presents a Bit-tracking Knowledge-based query tree (BKQT), which uses two techniques: knowledge, which stores all the tag IDs that can possibly occur, and bit tracking, which allows the reader to detect the locations of the collided bits in a collision slot. BKQT constructs a query tree for all possible tags, called a k-tree, by using knowledge while it constructs bit-collision cases and the corresponding actions for each node in this k-tree by using bit tracking. In the identification process, BKQT traverses this constructed k-tree and thus identifies the colliding tags faster by taking the actions according to the happening bit-collision cases. From the simulation results, BKQT can improve the identification time by 44.3%, 46.4%, and 25.1%, compared with the previous knowledge-based protocols, Knowledge query tree (KQT), Heuristic query tree (H-QT), query tree with Shortcutting and Couple Resolution (QTSC), respectively.

关键词： RFID knowledge-based query tree anti-collision protocol bit tracking

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Parallel Response Ternary query tree for RFID Tag Anti-Collision

Parallel Response Ternary Query Tree for RFID Tag Anti-Colli...

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2015 Workshop 5

作者： Ching-Nung Yang Song-Ruei Cai Li-Zhe Sun Department of Computer Science and Information Engineering National Dong Hwa University

A tag-collision(or missed reads) in RFID system(Radio Frequency Identification) system degrades the identification *** so-called tag collision is that a reader cannot identify a tag when more than one tags respond to a reader at the same *** are some major anti-collision protocols on resolving tag collision, e.g., ALOHA-based protocol, binary tree protocol, and query tree(QT) *** to date, most tag anti-collision protocols are QT *** protocols are categorized into M-ary query tree(QT).In the previous literature, choosing M = 3(i.e., a ternary QT(TQT)) was proven to have the optimum performance for tag ***, Yeh et *** parallel response approach to reduce the number of *** this paper, we combine the partial response and TQT to propose an effective parallel response TQT(PRTQT) ***-lation results reveal that our PRTQT outperforms Yeh et al.'s protocol and TQT protocol.

关键词： Radio Frequency Identification(RFID) Tag Collision query tree Ternary tree Parallel Response

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A tree-Based Approach to Support query Translation for Schema Mappings with Weights

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JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 2017年第1期33卷 251-270页

作者： Chang, Ya-Hui Lee, Chia-Zhen Zhuang, Si-Yen Natl Taiwan Ocean Univ Dept Comp Sci & Engn Keelung 202 Taiwan

query translation has been a central task for data integration or information sharing. In this paper, we assume that the source and target databases may be XML or relational, with the query languages Xquery and SQL, respectively. Besides, there may exist many possible mappings with different weights between two schemas, which are usually produced by automatic schema matching tools. We intend to output the most preferable query based on weights among all equivalent ones, so we need to properly represent the weighted schema mappings and input queries. Our approach is to first classify the schema representation into two basic units, i.e., collections and values, and apply mapping functions to represent the correspondence for each basic unit with weight information. We then propose a set of tree structures, collectively called CanForest, which show the structural constraints and semantics of the input query and assist in producing the output queries. We have constructed the complete translation system and shown its effectiveness. Experimental results also demonstrate that the system is very efficient.

关键词： Xquery SQL query translation schema mapping query tree

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Threshold jumping and wrap-around scan techniques toward efficient tag identification in high density RFID systems

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INFORMATION SYSTEMS FRONTIERS 2011年第4期13卷 471-480页

作者： Hsu, Ching-Hsien Chao, Han-Chieh Park, Jong Hyuk Kyungnam Univ Dept Comp Sci & Engn Masan Kyungnam South Korea Chung Hua Univ Dept Comp Sci & Informat Engn Hsinchu Taiwan Natl Ilan Univ Inst Comp Sci & Informat Engn Ilan Taiwan Natl Ilan Univ Dept Elect Engn Ilan Taiwan Natl Dong Hwa Univ Dept Elect Engn Hualien Taiwan

With the emergence of wireless RFID technologies, the problem of Anti-Collision has been arousing attention and instigated researchers to propose different heuristic algorithms for advancing RFID systems operated in more efficient manner. However, there still have challenges on enhancing the system throughput and stability due to the underlying technologies had faced different limitation in system performance when network density is high. In this paper, we present a Threshold Jumping (TJ) and a Wrap-Around Scan (WAS) techniques, which are query tree based approaches, aiming to coordinate simultaneous communications in high density RFID environments, to speedup tag identification, to increase the overall read rate and to improve system throughput in large-scale RFID systems. The main idea of the Threshold Jumping is to limit the number of collisions. When the number of collisions exceeds a predefined threshold, it reveals that tag density in RF field is too high. To avoid unnecessary enquiry messages, the prefix matching will be moved to next level of the query tree, alleviating the collision problems. The method of setting frequency bound indeed improves the efficiency in high density and randomly deployed RFID systems. However, in irregular or imbalanced RFID networks, inefficient situation may happen. The problem is that the prefix matching is performed in single direction level-order scheme, which may cause an imbalance query tree on which the right subtree always not been examined if the identification process goes to next level before scan the right sub-tree due to threshold jumping. By scanning the query tree from right to left in alternative levels, i.e., wrap-around, this flaw cold be ameliorated. To evaluate the performance of proposed techniques, we have implemented the TJ and the WAS method along with the query tree protocol. The simulation results show that the proposed techniques provide superior performance in high density environments. It is shown tha

关键词： Tag anti-collision query tree Wrap-around scan Threshold jumping

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An anti-collision algorithm for RFID-based robots based on dynamic grouping binary trees

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COMPUTERS & ELECTRICAL ENGINEERING 2017年 63卷 91-98页

作者： Zhang, Yin Yang, Fan Wang, Qian He, Qianlin Li, JiaCheng Yang, Yue Zhongnan Univ Econ & Law Sch Informat & Safety Engn Wuhan 430073 Hubei Peoples R China

This paper investigates the conventional algorithms for addressing the issue of tag collision in radio-frequency identification (RFID) systems. To improve the efficiency of RFID reader inquiry, this paper proposes an approach based on dynamic grouping binary trees, named DGBT, for RFID-based robots. Through DGBT, the collision probability and query times of RFID readers are lowered by adaptive anti-collision prefixes, the efficiency of RFID identification is improved via the group-based approach, and the binary-tree-based queries within groups are ensured to be stable, flexible, effective and practicable. Analysis and simulation verify that the query times and throughput rate are significantly improved by DGBT. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： RFID-based robots Anti-collision query tree Dynamic grouping mechanism

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Assigned tree Slotted Aloha RFID Tag Anti-Collision Protocols

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2013年第11期12卷 5493-5505页

作者： Zhang, Lijuan Zhang, Jin Tang, Xiaohu Southwest Jiaotong Univ Informat Secur & Natl Comp Grid Lab Chengdu 610031 Peoples R China Southwest Jiaotong Univ Sch Transportat & Logist Chengdu 610031 Peoples R China

With the development of radio frequency identification (RFID) technology, RFID systems have been used in various applications. But the tag collision problem greatly affects the performance of many RFID systems, especially in large scale tag identification environments. In this paper, we propose two new efficient tag anti-collision protocols, i.e., the assigned tree slotted Aloha (ATSA) protocol and the improved ATSA (ImATSA) protocol based upon Manchester encoding. The key technology is to apply the prefix matching idea to the dynamic frame slotted Aloha identification model by assigning a unique ID prefix to each frame and slot. Both theoretical and simulation results indicate that ImATSA can achieve an average system efficiency of around 58%.

关键词： RFID anti-collision tag identification Aloha query tree hybrid

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An Energy and Identification Time Decreasing Procedure for Memoryless RFID Tag Anticollision Protocols

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2016年第6期15卷 4234-4247页

作者： Landaluce, Hugo Perallos, Asier Onieva, Enrique Arjona, Laura Bengtsson, Lars Univ Deusto Deusto Inst Technol DeustoTech Bilbao 48007 Spain Chalmers Dept Comp Sci & Engn SE-41296 Gothenburg Sweden

Up to date energy-aware radio frequency identification (RFID) anticollision protocols are mainly focused on RFID systems using active tags. The introduction of RFID in portable devices, and the increasing popularity of passive tags, demands low energy-consumption anticollision protocols in environments with passive tags. Memoryless protocols present the simplest tag hardware that is beneficial for a low energy consumption. However, the excessive collisions required by these protocols increases the energy consumption, wasting a large number of tag transmitting bits. In this paper, a window procedure is presented to manage the length of the tags' bit-stream in order to limit the energy wastage in collisions. The bit window is applied to two memoryless anticollision protocols, the query tree protocol (QT) and the collision tree protocol (CT), producing the query window tree protocol (QwT) and the collision window tree protocol (CwT). Simulations show that the use of this window yields significant reductions in energy consumption and identification time. In addition, QwT and CwT are compared to state of the art memoryless protocols to confirm that CwT is an outstanding candidate for reducing energy consumption. Also, the results obtained show how the bit window procedure increases energy savings as the length of the tag ID increases.

关键词： RFID anti-collision memoryless protocols query tree collision tree bit-tracking energy aware

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Fault tolerant multiple event detection in a wireless sensor network

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JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING 2008年第9期68卷 1222-1234页

作者： Banerjee, Torsha Xie, Bin Agrawal, Dharma P. Univ Cincinnati Dept Comp Sci OBR Ctr Distributed & Mobile Comp Cincinnati OH 45221 USA

With an increasing acceptance of Wireless Sensor Networks (WSNs), the health of individual sensor is becoming critical in identifying important events in the region of interest. One of the key challenges in detecting event in a WSN is how to detect it accurately transmitting minimum information providing sufficient details about the event. At the same time, it is also important to devise a strategy to handle multiple events occurring simultaneously. In this paper, we propose a Polynomial-based scheme that addresses these problems of Event Region Detection (PERD) by having a aggregation tree of sensor nodes. We employ a data aggregation scheme, TREG (proposed in our earlier work) to perform function approximation of the event using a multivariate polynomial regression. Only coefficients of the polynomial (P) are passed instead of aggregated data. PERD includes two components: event recognition and event report with boundary detection. This can be performed for multiple simultaneously occurring events. We also identify faulty sensor(s) using the aggregation tree. Performing further mathematical operations on the calculated P can identify the maximum (max) and minimum (min) values of the sensed attribute and their locations. Therefore, if any sensor reports a data value outside the [min, max] range, it can be identified as a faulty sensor. Since PERD is implemented over a polynomial tree on a WSN in a distributed manner, it is easily scalable and computation overhead is marginal. Results reveal that event(s) can be detected by PERD with error in detection remaining almost constant achieving a percentage error within a threshold of 10% with increase in communication range. Results also show that a faulty sensor can be detected with an average accuracy of 94% and it increases with increase in node density. (c) 2008 Elsevier Inc. All rights reserved.

关键词： aggregation critical point event boundary faulty sensor polynomial query tree spatio-temporal correlation threshold

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APPROXIMATE - A query PROCESSOR THAT PRODUCES MONOTONICALLY IMPROVING APPROXIMATE ANSWERS

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 1993年第6期5卷 1056-1068页

作者： VRBSKY, SV LIU, JWS UNIV ILLINOIS DEPT COMP SCIURBANAIL 61801

This paper describes APPROXIMATE, a query processor that makes approximate answers available if part of the database is unavailable or if there is not enough time to produce an exact answer. The processor implements approximate query processing - the accuracy of the approximate result produced improves monotonically with the amount of data retrieved to produce the result. The monotone query processing algorithm of APPROXIMATE works within a standard relational algebra framework. APPROXIMATE maintains semantic information for approximate query processing on an underlying level and can be implemented on a relational database system with little change to the relational architecture. We show how APPROXIMATE is implemented to make effective use of the semantic support and describe the additional overhead required by APPROXIMATE.

关键词： APPROXIMATE OBJECT APPROXIMATE query PROCESSING CLASS HIERARCHY IMPRECISE COMPUTATION MONOTONE ALGORITHMS PARTIAL-ORDER RELATION query tree RELATIONAL ALGEBRA

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Optimizing large join queries using a graph-based approach

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2001年第2期13卷 298-315页

作者： Lee, C Shih, CS Chen, YH Natl Cheng Kung Univ Dept Comp Sci & Informat Engn Tainan 70101 Taiwan Univ Illinois Dept Comp Sci Urbana IL 61801 USA Natl Chiayi Univ Dept Informat & Comp Sci Chiayi 60054 Taiwan

Although many query tree optimization strategies have been proposed in the literature, there still is a lack of a formal and complete representation of all possible permutations of query operations (i.e., execution plans) in a uniform manner. A graph-theoretic approach presented in this paper provides a sound mathematical basis for representing a query and searching for an execution plan. In this graph model, a node represents an operation and a directed edge between two nodes indicates the order of executing these two operations in an execution plan. Each node is associated with a weight and so is an edge. The weight is an expression containing optimization required parameters, such as relation size, tuple size, join selectivity factors. All possible execution plans are representable in this graph and each spanning tree of the graph becomes an execution plan, It is a general model which can be used in the optimizer of a DBMS for interal query representation. On the basis of this model, we devise an algorithm that finds a near optimal execution plan using only polynomial time. The algorithm is compared with a few other popular optimization methods. Experiments show that the proposed algorithm is superior to the others under most circumstances.

关键词： large join query graph theory join cost query tree query optimization

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