Showing papers on "Sensor node published in 1999"

Automated operation and security system for virtual private networks

Abstract: A node device for providing secure communication services over a data network, such as the Internet or another public or private packet switched network, to multiple computers that are coupled through the node device and multiple other node devices. The node device includes a network communication interface for coupling the node device to the data network. The node device includes a data storage containing cryptographic information including information that is unique to the node device. The node device also includes a tunneling communication service coupled to the network interface configured to maintaining an encrypted communication tunnel with each of multiple other node devices using the cryptographic information. For example, the encrypted communication tunnels are implemented using the IPsec or PPTP protocols. The node device includes a routing database for holding routing data and a router coupled to the tunneling communication service and to the routing database. The router can pass communication from one communication tunnel to another. A centralized server can be used to control the node devices in a centralized manner, thereby reducing or eliminating on-site administration of node devices.

Development platform for self-organizing wireless sensor networks

Abstract: Distributed microsensor networks, built from collections of nodes each having the ability to sensor their environment, process the raw sensor data in cooperation with other neighboring nodes into information and then communicate that information to end users. These systems are designed to be self-organizing in the sense of establishing and maintaining their own network without the need for specialistic operators. In most envisioned applications, wireless communications are the most practical means of interconnection, eliminating the internode cabling. Long periods of autonomous operations in remote environments will need battery or other renewable energy sources. In order to prolong battery life, all node hardware and software functions need to be designed to consume minimal power. In general, a node will expend energy on local processing of sensor data to produce compressed information in order to reduce communications. These network systems are intended to support large numbers of such nodes to cover large geographic areas.

Wireless environmental sensor system

Abstract: An environmental sensor system that communicates sensor data to a receiving unit using wireless means such as a radio frequency signal. The receiving unit interfaces with a controllable system, possibly affecting its operation. This arrangement allows one or more sensor and transmitter units to be remotely mounted at a distance from the receiver, without regard to installation complications that often result with a hardwired type units. In the preferred embodiment, an irrigation system is interfaced wirelessly with an environmental sensor such as a rain sensor. The rain sensor is contemplated such that in the event of sufficient rainfall, a wireless signal is transmitted to the receiver unit, which in turn interfaces with an irrigation controller resulting in the cessation of watering cycles until the sensor system provides another wireless directive to resume watering.

Communication node and communication terminal

Abstract: The disclosed communication node has a function for recognizing one communication node on the first network as one of constituent elements in own communication node, and a function for disclosing an own configuration information regarding the constituent elements as recognized above, to another communication node on the second network. Also, the disclosed communication terminal has a function for disclosing functions in the own communication terminal as Sub Units in an AV/C (Audio/Visual Control) protocol executed on an IEEE 1394 bus, and a function for receiving at least a part of information regarding Sub Units existing in the communication node on the second network with which it is communicating. Together, these communication node and communication terminal make it possible to transmit various information transferred on the IEEE 1394 bus, to the radio node that is connected by the radio interface, and it becomes possible to execute the data communications as if the connection to the IEEE 1394 bus is made by the radio interface.

Monitoring system and network system

Abstract: PROBLEM TO BE SOLVED: To attain effective utilization of a band of a communication path in a monitoring system. SOLUTION: An operation panel processor 20 allocates a specified band to each communication between a camera node 40 for performing communication of picture data whose rate of generation is even and a monitor node 18 and allocates a specified band to the whole communication between each sensor node 50 for performing communication of alarm information whose rate of generation is uneven and an operation panel processor 30. Relating to A0 operation panel processor 30 which reallocates a band between the camera node 40 and the monitor node 18 so that the number of bands becomes fewer when a traffic of a network 10 increases the camera node 40 transmits the picture data by using the allocated band. Each sensor node 50 transmits generated alarm information by using an arbitrary band.

Sensor signal conditioner with calibration

Abstract: The system comprises a sensor for sensing an input between a first, minimum sensor input value and a second, maximum sensor input value. The sensor is subject to offset and gain errors. The system further includes a microprocessor having first and second output signals and a signal conditioner coupled between the sensor and the microprocessor. The signal conditioner includes circuitry for minimizing the sensor offset error and circuitry for minimizing the sensor gain error. The offset minimizing circuitry includes circuitry responsive to the first microprocessor signal for generating a signal substantially equal to zero when the sensor input value is at the minimum sensor value. The gain error minimizing means includes circuitry responsive to the second microprocessor signal for generating a signal substantially equal to the maximum signal conditioner value when the sensor input is at the maximum sensor value.

A fully integrated sensor interface chip

Abstract: A single-chip sensor signal conditioning system is described. The chip contains two 20-bit sigma-delta A-D converters. The main ADC has a rail-to-rail input buffer and PGA. There is a 12-bit DAC and current sources for sensor excitation and circuitry for sensor fault detection. An 8052 microcontroller core is provided for processing the ADC outputs. There is 640 bytes of user flash memory and 8k bytes of program flash. Clocking is from a 32kHz watch crystal oscillator. An on-chip PLL multiplies up this frequency to provide programmable clocks for the microcontroller. The die area is 17mm2on a 0.5µm TPTM flash memory process. Power consumption is 10mW at 3V.

System and method for communicating data among a plurality of digital signal processors

Abstract: A system for communicating data among digital signal processors (DSPs) includes DSPs and a shift register. Each DSP includes a transmit node that communicates data and a receive node that receives data. The shift register includes an input node coupled to the transmit node of each DSP and an output node coupled to the receive node of each DSP. The input node receives data from the transmit node of each DSP, and the output node communicates the data received at the input node to the receive node of each DSP.

Fuzzy control in the deployable autonomous distributed system

Abstract: The Deployable Autonomous Distributed System is an ocean surveillance system that contains a field of sensor nodes. Each sensor node provides target detections to a master node in the field for fusion by a Multiple Hypothesis Tracker Correlator (MHTC). The overall performance of a fusion engine depends upon the set of parameters that are used by the Multiple Hypothesis Tracker. Although a static set of parameters may work well over a wide range of scenarios, they may not lead to optimal performance in all cases. This paper addresses Level 4 fusion to improve performance of the data fusion system at the master node by using a fuzzy logic controller to adaptively tune the parameters. By using a set of linguistic rule based fuzzy logic algorithms, the tuning parameters of the MHTC are modified. A set of metrics are used to determine the added worth of the fuzzy logic controller.

The sensor network based on LONWORKS technology

Abstract: This paper presents a sensor network based on LonWorks technology. The network structure, its protocol and the sensor nodes in it are discussed. Also, the implementation method of such network, including its hardware and software is given. Because of the characteristic of the sensor network based on LonWorks, such as the protocol consistent with the ISO/OSI model, the interoperability and the multiple medium support etc., the sensor network will get more applications in the future.