一种基于数字水印的无线传感器网络敏感数据通信协议

基于信息隐藏技术开发了一种用于无线传感器网络的隐蔽的敏感数据通信协议.通过牺牲大值传感数据的精度来隐蔽地传输敏感数据,可广泛应用于多个领域.     

Commercial digital image libraries,digital images and digital discontent

Publications such as consumer magazines rely heavily on image libraries as sources for the images they use in their issues. Traditionally, magazine editorial staff have discussed their image requirements over the telephone with library staff and the library has conducted the search. Many libraries have now developed Web sites and their customers search them for images themselves. A minority have e-commerce capabilities, and enable customers to purchase and download digital images from their sites. This survey found that magazine staff do not often choose to search digital libraries, preferring instead to continue to contact the library by telephone. Most also choose not to buy the use of digital images, but prefer to continue to work with conventional transparencies and slides. The reasons for these preferences, and the reasons they are unlikely to change in the short term, are explored.     

QoS and data relaying for wireless sensor networks

In this paper we study the effects of data relaying in wireless sensor networks (WSNets) under QoS constraints with two different strategies. In the first, data packets originating from the same source are sent to the base station possibly along several different paths, while in the second, exactly one path is used for this purpose. The two strategies correspond to splitting and not splitting relaying traffic, respectively. We model a sensor network architecture based on a three-tier hierarchy of nodes which generalizes to a two-tier WSNet with multiple sinks. Our results apply therefore to both types of networks. Based on the assumptions in our model, we describe several methods for computing relaying paths that are optimal with respect to energy consumption and satisfy QoS requirements expressed by the delay with which data are delivered to the base station(s). We then use our algorithms to perform an empirical analysis that quantifies the performance gains and losses of the splittable and unsplittable traffic allocation strategies for WSNets with delay-constrained traffic. Our experiments show that splitting traffic does not provide a significant advantage in energy consumption, but can afford strategies for relaying data with a lower delay penalty when using a model based on soft-delay constraints.     

Bulk data dissemination in wireless sensor networks: Modeling and analysis

Wireless sensor networks (WSNs) have recently gained a great deal of attention as a topic of research, with a wide range of applications being explored. Bulk data dissemination is a basic building block for sensor network applications. The problem of designing efficient bulk data dissemination protocols has been addressed in a number of recent studies. The problem of accurately analyzing the performance of these protocols, however, has not been addressed sufficiently in the literature. In this work, we show a way of accurately analyzing the performance of bulk data dissemination protocols in WSNs. Our model can be applied to practical network topologies by use of the shortest propagation path. Our model is accurate by considering topological information, impact of contention, and impact of pipelining. We validate the analytical results through testbeds and detailed simulations. Results show that the analytical results fit well with the testbed results and simulation results. Further, we demonstrate that the analytical results can be used to aid protocol design for performance optimizations, e.g., page size tuning for shortening the completion time.     

基于嵌入式技术的水声传感网和#br# VHF通信网络的互联网关设计

针对水上船舶用户对水下网络监测存在长延时和高费用问题,结合水声传感网特点和水上船舶常用VHF通信设备,采用嵌入式技术,提出一种面向水上船舶用户的水声传感网和水上VHF通信网的无线网关设计方案,对网关的软硬件系统进行设计。仿真结果表明,嵌入式网关实现了水声传感网和VHF通信网的互联互通,具有较高的理论与实际应用价值。     

Real-time data management on wireless sensor networks: A survey

In the recent past, search in sensor systems focused on node hardware constraints and very limited energy resources. But nowadays, that new applications need data processing with temporal constraints in their tasks; then one of the new challenges faced by wireless sensor networks (WSNs) is handling real-time storage and querying the data they process. Two main approaches to storage and querying data are generally considered warehousing and distributed. The warehousing approach stores data in a central database and then queries may be performed to it. In a distributed approach, sensor devices are considered as local databases and data are managed locally. The data collected by sensors must represent the current state of the environment; for this reason they are subject to logic and time constraints. Then, this paper identifies the main specifications of real-time data management and presents the available real-time data management solutions for WSNs, in order to discuss them and identify some open issues and provide guidelines for further contributions.     

Practical data compression in wireless sensor networks: A survey

Power consumption is a critical problem affecting the lifetime of wireless sensor networks. A number of techniques have been proposed to solve this issue, such as energy-efficient medium access control or routing protocols. Among those proposed techniques, the data compression scheme is one that can be used to reduce transmitted data over wireless channels. This technique leads to a reduction in the required inter-node communication, which is the main power consumer in wireless sensor networks. In this article, a comprehensive review of existing data compression approaches in wireless sensor networks is provided. First, suitable sets of criteria are defined to classify existing techniques as well as to determine what practical data compression in wireless sensor networks should be. Next, the details of each classified compression category are described. Finally, their performance, open issues, limitations and suitable applications are analyzed and compared based on the criteria of practical data compression in wireless sensor networks.     

Post-processing in wireless sensor networks: Benchmarking sensor trace files for in-network data aggregation

Wireless sensor network research usually focuses on the reliable and efficient collection of data. In this paper we target on the next step in the lifetime of traces: we aim at investigating and evaluating, by qualitative and quantitative means, data repositories of already collected measurements. Concerning the collected datasets, several important topics arise like the need of exchanging traces between researchers using a common representation of the traces and the need for common classification of the traces based on a commonly agreed set of statistical characteristics for in retrospect utilization. In order to qualitatively address these issues, we propose the use of a novel set of metrics focusing on the in-network data-aggregation problem class. These metrics enable reliable evaluation of algorithms using the same benchmark traces (both in average cases and “stressful” setups) removing the need for running algorithms in a real testbed, at least in the initial development stage. We present the results of our research as a first approach for addressing this problem, and in order to confirm our method, we characterized several traces with the proposed metrics. We validate the metrics by predicting the performance of three data-aggregation schemes using the available traces and checking the results by actually running the algorithms.     

Video digital libraries: contributive and decentralised

Technology usage is changing rapidly and is becoming a more mobile, more social and more multimedia-based experience. This is especially true in the area of content creation where mobile social applications used by crowds of people are challenging traditional ways of creating and distributing content, especially for applications like news dissemination. Libraries have traditionally functioned as repositories where the information content of a society is analysed, curated, organised and stored, acting as a permanent record of what is to be remembered from a society. How can this function be achieved by present-day libraries attempting to cope with mobile, social, multimedia content who’s nature and utility of which change the type of information we wish to curate and store? This information is both dynamic and organic, posing challenges to the more fixed models of information in digital libraries. In this article we describe two digital library systems that archive video content from the sports domain, and which support user annotations and merging of diverse information sources in an integrated way. We report on analysis of the deployment of these two systems and highlight how they extend the traditional role of a (digital) library.     

CCS-MAC: Exploiting the overheard data for compression in wireless sensor networks

Both the overhearing and overhearing avoidance in a densely distributed sensor network may inevitably incur considerable power consumption. In this paper we propose a so-called CCS-MAC (collaborative compression strategy-based MAC) MAC protocol which facilitates to exploit those overheard data that is treated useless in traditional MAC protocols for the purpose of cost and energy savings. Particularly the CCS-MAC enables different sensor nodes to perform data compression cooperatively with regard to those overheard data, so that the redundancy of data prepared for the link layer transmission can be totally eliminated at the earliest. The problem of collaborative compression is analyzed and discussed along with a corresponding linear programming model formulated. Based on it a heuristic node-selection algorithm with a time complexity of (O(N²)) is proposed to the solve the linear programming problem. The node-selection algorithm is implemented in CCS-MAC at each sensor node in a distributed manner. The experiment results verify that the proposed CCS-MAC scheme can achieve a significant energy savings so as to prolong the lifetime of the sensor networks so far.     

In-network data acquisition and replication in mobile sensor networks

This paper assumes a set of n mobile sensors that move in the Euclidean plane as a swarm. Our objectives are to explore a given geographic region by detecting and aggregating spatio-temporal events of interest and to store these events in the network until the user requests them. Such a setting finds applications in mobile environments where the user (i.e., the sink) is infrequently within communication range from the field deployment. Our framework, coined SenseSwarm, dynamically partitions the sensing devices into perimeter and core nodes. Data acquisition is scheduled at the perimeter, in order to minimize energy consumption, while storage and replication takes place at the core nodes which are physically and logically shielded to threats and obstacles. To efficiently identify the nodes laying on the perimeter of the swarm we devise the Perimeter Algorithm (PA), an efficient distributed algorithm with a low communication complexity. For storage and fault-tolerance we devise the Data Replication Algorithm (DRA), a voting-based replication scheme that enables the exact retrieval of values from the network in cases of failures. We also extend DRA with a spatio-temporal in-network aggregation scheme based on minimum bounding rectangles to form the Hierarchical-DRA (HDRA) algorithm, which enables the approximate retrieval of events from the network. Our trace-driven experimentation shows that our framework can offer significant energy reductions while maintaining high data availability rates. In particular, we found that when failures across all nodes are less than 60%, our framework can recover over 80% of detected values exactly.     

Securing distributed data storage and retrieval in sensor networks

Sensor networks have been an attractive platform for pervasive computing and communication. However, they are vulnerable to attacks if deployed in hostile environments. The past research of sensor network security has focused on securing information in communication, but how to secure information in storage has been overlooked. Meanwhile, distributed data storage and retrieval have become popular for efficient data management in sensor networks, which renders the absence of schemes for securing stored information to be a more severe problem. Therefore, we propose three evolutionary schemes, namely, the simple hash-based (SHB) scheme, the enhanced hash-based (EHB) scheme, and the adaptive polynomial-based (APB) scheme, to deal with the problem. All the schemes have the properties that only authorized entities can access data stored in the sensor network, and the schemes are resilient to a large number of sensor node compromises. The EHB and the APB schemes do not involve any centralized entity except for a few initialization or renewal operations, and thus support secure, distributed data storage and retrieval. The APB scheme further provides high scalability and flexibility, and hence is the most suitable among the three schemes for real applications. The schemes were evaluated through extensive analysis and TOSSIM-based simulations.     

Min-max optimal data encoding and fusion in sensor networks

The paper considers a sensor network whose sensors observe a common quantity and are affected by arbitrary additive bounded noises with a known upper bound. During the experiment, any sensor can communicate only a finite and given number of bits of information to the decision center. The contributions of the particular sensors, the rules of data encoding, decoding, and fusion, as well as the estimation scheme should be designed to achieve the best overall performance in estimation of the observed quantity by the decision center. An optimal algorithm is obtained that minimizes the maximal feasible error. It is shown that it considerably outperforms the algorithm proposed in recent papers in the area and examined only in the idealized case of noiseless sensors.     

一种容错的传感器网络数据融合隐私保护算法

由于网络通信具有易错的特点,提出一种具有容错性的隐私保护数据聚集算法。通过椭圆曲线加密方案对节点数据进行加密,保证数据的隐私性,采用加同态加密技术,实现了端到端的聚集加密,节省能耗和带宽。同时,构造轨道图拓扑结构,使得每个节点有多个父节点,当节点与主父节点发生链路失效时,其他父节点能够修复聚集值。仿真实验结果显示,提出的方案在适当增加通信量的情况下,具有较高的数据安全性、很好的容错性和高精度的聚集值。     

Secure data aggregation in wireless sensor networks: A comprehensive overview

Wireless sensor networks often consists of a large number of low-cost sensor nodes that have strictly limited sensing, computation, and communication capabilities. Due to resource restricted sensor nodes, it is important to minimize the amount of data transmission so that the average sensor lifetime and the overall bandwidth utilization are improved. Data aggregation is the process of summarizing and combining sensor data in order to reduce the amount of data transmission in the network. As wireless sensor networks are usually deployed in remote and hostile environments to transmit sensitive information, sensor nodes are prone to node compromise attacks and security issues such as data confidentiality and integrity are extremely important. Hence, wireless sensor network protocols, e.g., data aggregation protocol, must be designed with security in mind. This paper investigates the relationship between security and data aggregation process in wireless sensor networks. A taxonomy of secure data aggregation protocols is given by surveying the current “state-of-the-art” work in this area. In addition, based on the existing research, the open research areas and future research directions in secure data aggregation concept are provided.     

RFID系统与传感器网络中的数据处理综述*

综述了普适计算领域中RFID(电子标签)系统和传感器网络这两个研究热点,阐述了它们的基本概念和技术特性,并对两种系统作了比较和分析,从而引出了数据处理这一核心概念.探讨了两种系统中数据处理需要研究的问题,特别是按照数据处理的流程对两种系统中的数据处理方法进行了较为详细的归纳和分析.