Showing papers on "Sensor web published in 2000"

Constraints and approaches for distributed sensor network security

Abstract: Executive Summary Confidentiality, integrity, and authentication services are critical to preventing an adversary from compromising the security of a distributed sensor network. Key management is likewise critical to establishing the keys necessary to provide this protection. However, providing key management is difficult due to the ad hoc nature, intermittent connectivity, and resource limitations of the sensor network environment. As part of the SensIT program, NAI Labs is addressing this problem by identifying and developing cryptographic protocols and mechanisms that efficiently provide key management security support services. This document describes our sensor network constraints and key management approaches research for FY 2000. As a first step, NAI Labs has researched battlefield sensor and sensor network technology and the unique communications environment in which it will be deployed. We have identified the requirements specific to our problem of providing key management for confidentiality and group-level authentication. We have also identified constraints, particularly energy consumption, that render this problem difficult. NAI Labs has developed novel key management protocols specifically designed for the distributed sensor network environment, including Identity-Based Symmetric Keying and Rich Uncle. We have analyzed both existing and NAI Labs-developed keying protocols for their suitability at satisfying identified requirements while overcoming battlefield energy constraints. Our research has focused heavily on key management energy consumption, evaluating protocols based on total system, average sensor node, and individual sensor node energy consumption. We examined a number of secret-key-based protocols, determining some to be suitable for sensor networks but all of the protocols have flexibility limitations. Secret-key-based protocols are generally energy-efficient, using encryption and hashing algorithms that consume relatively little energy. Security of secret-key-based protocols is generally determined by the granularity of established keys, which vary widely for the protocols described herein. During our examination of these protocols we noted that some of these protocols are not sufficiently flexible for use in battlefield sensor network, since they cannot efficiently handle unanticipated additions of sensor nodes to the network. Our Identity-Based Symmetric Keying protocol and the less efficient Symmetric Key Certificate Based Protocol are well suited for certain sensor networks, establishing granular keys while consuming relatively little energy. However, all of the secure secret-key-based protocols use special nodes that operate as Key Distribution Centers (or Translators). The sensor nodes communicate with these centers exchanging information as part of the key establishment process. Since these special nodes are expected to make up less than 1% of the sensor …

SensorSim: a simulation framework for sensor networks

Abstract: The advent of wireless micro sensors promises many yet unrealized benefits. A network of such sensors or “sensor network” introduces a new set of challenges. Besides being able to communicate effectively, sensor networks have demanding sensing tasks. First, they must be aware of their environment and oftentimes are required to adapt to their surroundings. Second, they must coordinate among them to perform a greater group-sensing task. In this context, the study of sensor networks has numerous other aspects besides communication. To create a better understanding of sensor networks and to facilitate the development of new protocols and applications, detailed simulation and performance evaluation techniques need to be developed. In this paper, we introduce our ongoing efforts in the development of SensorSim, a simulation framework that introduces new models and techniques for the design and analysis of sensor networks. SensorSim inherits the core features of traditional event driven network simulators, and builds up new features that include ability to model power usage in sensor nodes, hybrid simulation that allows the interaction of real and simulated nodes, new communication protocols and real time user interaction with graphical data display. After discussing the details of SensorSim, we provide our current results, that demonstrate various capabilities of SensorSim.

WebCQ-detecting and delivering information changes on the web

Abstract: WebCQ is a prototype system for large-scale Web information monitoring and delivery. It makes heavy use of the structure present in hypertext and the concept of continual queries. In this paper we discuss both mechanisms that WebCQ uses to discover and detect changes to the World Wide Web (the Web) pages e ciently, and the methods to notify users of interesting changes with a personalized customization. The WebCQ system consists of four main components: a change detection robot that discovers and detects changes, a proxy cache service that reduces communication tra cs to the original information servers, a personalized presentation tool that highlights changes detected by WebCQ sentinels, and a change noti cation service that delivers fresh information to the right users at the right time. A salient feature of our change detection robot is its ability to support various types of web page sentinels for detecting, presenting, and delivering interesting changes to web pages. This paper describes the WebCQ system with an emphasis on general issues in designing and engineering a large-scale information change monitoring system on the Web.

Sensor Information Networking Architecture

Abstract: The advent of technology has facilitated the development of networked systems of extremely small, low-power devices that combine programmable general-purpose computing with multiple sensing and wireless communication capability. This networked system of programmable sensor nodes, which together form a sensor network, poses unique challenges on how information collected by, and stored within, the sensor network could be queried and accessed, and how concurrent sensing tasks could be executed internally and programmed by external users. In this paper, we describe SINA (Sensor Information Networking Architecture), which facilitates the querying, monitoring and tasking of sensor networks. We model a sensor network as a collection of massively distributed objects, and SINA plays the role of middleware that facilitates the adaptive organization of sensor information. The SINA kernel provides a set of configuration and communication primitives that enable the scalable, robust and energy-efficient organization of, and interactions among, sensor objects. On top of the SINA kernel is a programmable substrate that follows the spreadsheet paradigm and provides mechanisms to create associations among sensor nodes. Users then access information within a sensor network using declarative queries and perform tasks using programmable scripts. Issues concerning interworking between stationary sensor networks and mobile nodes are also addressed.

Sensor Web for in situ exploration of gaseous biosignatures

Abstract: A Sensor Web is a system of intra-communicating spatially distributed sensor pods that can be deployed to monitor and explore new environments. By its very nature, the Sensor Web provides spatio-temporal data in a form consistent with that needed for environment modeling and represents a new paradigm for in situ monitoring and exploration. For example, a wireless web of scattered sensor pods on the Martian surface is an ideal way to pursue gaseous biosignature searches. Sensor Web climate and agricultural monitoring on Earth (particularly when coupled with remote measurements) characterize significant commercial opportunities for this technology. Recent laboratory demonstrations at the Jet Propulsion Laboratory (JPL) have shown the potential of current Sensor Web technology, These demonstrations are leading to a JPL effort to field a Sensor Web in Baja California to examine gaseous biosignatures from the microbial mats there.

S-NETS: Smart Sensor Networks

Abstract: The utilization of nonmobile, distributed sensor and communication devices by a team of mobile robots offers performance advantages in terms of speed, energy, robustness and communication requirements. Models of mobile robots with on-board sensors, a communication protocol and the S-Net system are established. Algorithms are defined for the S-Net which perform cooperative computation and provide information about the environment. Behaviors include robots going to or surrounding a temperature source. The simulation experiments show that the S-Net performs well, and is particularly robust with respect to noise in the environment. System cost versus performance is studied, and guidelines are formulated for which the S-Net system out-performs the non-S-Net system.

Providing a differentiated quality of service in a World Wide Web server

Abstract: This paper presents a strategy of extending a Web server to be able to differentiate between requests in different classes. This is required because most Web servers are unable to do this by themselves. We present our strategy and its design along with some initial performance results.

Security and Deployment Issues in a Sensor Network

Abstract: We are facing an growing demand in deploying large scale sensor networks in the real world. However, there are still many obstacles before we can proceed. Security is a major concern as we need to be sure that the data we receive is authentic and confidential, and have not been tampered with. This is especially difficult because sensors have very limited resources and we cannot guarantee physical security of the sensors. Limited bandwidth is another problem as we scale up the number of sensors. We need to ensure that we achieve fairness and do not starve any sensors. We present our design and implementation to address these issues, and describe our deployment of a real sensor network and the problems that we encountered. Our security protocol works well on sensors with 8KB of memory and 4MHz 8-bit Atmel processors. Our adaptive transmission scheme achieves fairness among sensors in the network and prevents starvation. We also implemented two applications: people tracking and light sensing.

Sensor management in a sensor-rich environment

Abstract: This paper presents an adaptation of a comprehensive sensor management model, initially developed for C3I applications, to a new class of problems, a data rich, information poor, sensor rich environment. The sensor management model described is a hybrid distributed and hierarchical model in which the sensor scheduling function is distributed across system functional or physical boundaries with global oversight of mission goals and information requests maintained by a centralized Mission Manager. The introduction of a meta-scheduler block is only a n artifact of the opportunity afforded by the large number of sensors to implement a natural subdivision of a single sensor schedule into several spatially distributed sensor schedulers. System performance is enhanced by allowing local autonomy at the sensor, by distributing sensor scheduling among subsystems, and through an interrupt driven process in which local sensor measurements are abstracted to obtain global context. An aircraft health and usage monitoring system, a contemporary example of a sensor rich environment, is used to illustrate the issues involved in extending sensor management beyond C3I environments.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An open-standard smart sensor architecture and system for industrial automation

Abstract: An enabling sensor technology for prognostic and health management (PHM) is the open-standard smart sensor architecture. Historically, closed or proprietary sensor buses were used to collect distributed analog sensor data to a central point for digitization. Such a system would satisfy its initial constraints, but suffer when the need for future expansion or flexibility was required. Digital sensor buses addressed technical performance issues, but also fell short of an open-standard that would enable any sensor to work on any bus. This work of establishing an open-standard smart sensor architecture and then implementing a sensor system for PHM is described.

A software tool for designing intelligent sensors

Abstract: The purpose of this paper is to present a new model of intelligent sensor, and a set of software tools based on this model. At the origin of this model, studies were made in order to simplify the work of intelligent sensor designers, and to ensure a reliable conception of these sensors. After a description of the context, the paper shows the operating mode approach used to create the intelligent sensor model. Our laboratory has developed a tool for automatic generation of intelligent sensor software and a Windows based testing software tool. This tool uses a textual representation of the sensor model. The testing software can be connected to the sensor via a serial link, a fieldbus or a TCP link. An application to the design of intelligent functionalities for an ultrasonic sensor is presented.

Adaptive Management of Computing and Network Resources for Spacecraft Systems

Abstract: It is likely that NASA's future spacecraft systems will consist of distributed processes which will handle dynamically varying workloads in response to perceived scientific events, the spacecraft environment, spacecraft anomalies and user commands. Since all situations and possible uses of sensors cannot be anticipated during pre-deployment phases, an approach for dynamically adapting the allocation of distributed computational and communication resources is needed. To address this, we are evolving the DeSiDeRaTa adaptive resource management approach to enable reconfigurable ground and space information systems. The DeSiDeRaTa approach embodies a set of middleware mechanisms for adapting resource allocations, and a framework for reasoning about the real-time performance of distributed application systems. The framework and middleware will be extended to accommodate (1) the dynamic aspects of intra-constellation network topologies, and (2) the complete real-time path from the instrument to the user. We are developing a ground-based testbed that will enable NASA to perform early evaluation of adaptive resource management techniques without the expense of first deploying them in space. The benefits of the proposed effort are numerous, including the ability to use sensors in new ways not anticipated at design time; the production of information technology that ties the sensor web together; the accommodation of greater numbers of missions with fewer resources; and the opportunity to leverage the DeSiDeRaTa project's expertise, infrastructure and models for adaptive resource management for distributed real-time systems.

Smart Sensor Web: Web-based exploitation of sensor fusion for visualization of the tactical battlefield

Abstract: Smart Sensor Web (SSW) is a recent DUSD(S&T) initiative inspired by extraordinary technological advances in sensors and microelectronics and by the emergence of the Internet as a real time communication tool. The overall vision for SSW is an intelligent Web-centric distribution and fusion of sensor information that provides greatly enhanced situational awareness, on demand, to Warfighters at lower echelons. Emphasis is on multisensor fusion of large arrays of local sensors, joined with other assets, to provide real time imagery, weather, targeting information, mission planning, and simulations for military operations on land, sea, and air. The paper gives an overview of this new initiative, highlights some of the technology challenges in sensor/information fusion, and presents a program approach for near-term demonstrations and long-term solutions, involving the DoD, National Labs, commercial industry, and academia.

Navigation planning to guide concept understanding in the World Wide Web

Abstract: This paper describes navigation planning that generates a plan for guiding concept understanding in the WWW. It also has the ability to generate operators during planning from Web pages. For understanding a concept, it is a useful way to browse for relevant Web pages in the WWW. However this task is very hard because the user has to search for them in the vast WWW. To deal with this problem, we propose navigation planning to generate a sequence of Web pages by which a user systematically understand a concept.

The next-generation distributed-object Web and its application to sports medicine

Abstract: A significant strength of the current World Wide Web (Web) includes the striking similarity between "a document" and "an object", as defined by distributed object computing. In effect, the Web is a simple-minded distributed object system. It is generally recognized that current Web technologies are insufficient for supporting complex, enterprise-class applications such as distributed, network-based healthcare applications. Currently, several Web-based technologies are under development to support the evolution of the commodity Web toward a true "object-oriented" paradigm. These technologies and the associated risk, utility and scalability of this type of deployment in modern healthcare-related enterprises are the focus of our report.