Bing Jiang

Battery-free wireless identification and sensing

The Wireless Identification and Sensing Platform (WISP) project explores an approach to provide power for sensor networks, based on passive radio-frequency-identification technology. In traditional passive RFID systems, ambient high-power readers interrogate battery-free devices, called tags, that modulate the interrogating signal to communicate a unique identifier to the reader. The WISP project aims to augment RFID tags with sensors so that tags can also send sensed data to the readers. We call these augmented tags wisps. Basing wisps on RFID has some immediate advantages. RFID tags communicate to ambient readers over distances of up to eight meters. Solutions compatible with RFID standards might therefore find quicker acceptance and see faster improvement than other solutions.

RFID-based techniques for human-activity detection

The iBracelet and the Wireless Identification and Sensing Platform promise the ability to infer human activity directly from sensor readings.

Energy Scavenging for Inductively Coupled Passive RFID Systems

Deployment of passive radio-frequency identification (RFID) systems or RFID-enhanced sensor networks requires good understanding of the energy scavenging principles. This paper focuses on the energy scavenging design considerations of inductively coupled passive HF RFID systems. The theoretical estimation of the power by a loop antenna is derived, and the effect of the design parameters on the harvested power is investigated. It is shown that the power delivery performance is largely affected by the tag load at the reader. An adaptive matching circuit at the reader is proposed for achieving optimum power delivery performance when the reader has a variable load. Experimental studies confirm analytical derivations

I sense a disturbance in the force: Unobtrusive detection of interactions with rfid-tagged objects

A novel method to infer interactions with passive RFID tagged objects is described. The method allows unobtrusive detection of human interactions with RFID tagged objects without requiring any modifications to existing communications protocols or RFID hardware. The object motion detection algorithm was integrated into a RFID monitoring system and tested in laboratory and home environments. The paper catalogs the experimental results obtained, provides plausible models and explanations and highlights the promises and future challenges for the role of RFID in ubicomp applications.

Some methods for privacy in RFID communication

For RFID tags to gain general acceptance, they will have to offer powerful and flexible privacy mechanisms. After reviewing existing and upcoming privacy mechanisms for RFID privacy, we propose that a key aspect of RFID communication with passive tags, namely its required energy transference from an external antenna, may offer promise when developing privacy mechanisms. We present two proposals for such mechanisms. In the first mechanism, analysis of the received signal by the tags can be used to estimate reader distance (and hence trust). We show that a simple metric analogous to signal to noise ratio correlates well with rough distance. In the second, antenna energy is used to power a tiered authentication scheme, in which tags reveal more information about themselves to more trusted and/or “energetic” readers.

Unobtrusive long-range detection of passive RFID tag motion

This paper presents a novel method for detecting the motion of passive radio-frequency-identification (RFID) tags within the field of a detecting antenna. The method allows the unobtrusive detection of human interactions with RFID-tagged objects without requiring any modifications to existing communications protocols or RFID hardware. We use the response rate (a metric in lieu of the true received RF-signal intensity) at the reader to study the impact of tag translation, rotation, and coupling, as well as environmental effects. Performance is improved by introducing the idea of multiple tags/readers. Movement-detection algorithms are developed and integrated into the RFID monitoring system, and verified by experiments that demonstrate excellent results.

ID modulation: embedding sensor data in an RFID timeseries

This paper reports the first use of ID Modulation to embed a bitstream representing sensor information in a standards-compliant Radio Frequency Identification (RFID) channel. Like other forms of information hiding, ID Modulation embeds a new, lower bit-rate channel in a pre-existing host channel, without requiring any changes to the protocols defining the host channel. Like most other forms of information hiding, the embedded data is represented as correlations introduced into the host channel data stream. Most previous applications of information hiding have emphasized either secrecy (as in steganography) or robustness to removal (as in watermarking). The benefit of information hiding that is most important for the application reported here is backward compatibility with pre-existing standards and hardware. It has allowed us to build a new communication layer (for transmitting sensor data) on top of current RFID infrastructure.

Robotic monitoring of power systems

Monitoring of electric power systems in real time for reliability, aging status, and presence of incipient faults requires distributed and centralized processing of large amounts of data from distributed sensor networks. To solve this task, cohesive multidisciplinary efforts are needed from such fields as sensing, signal processing, control, communications, optimization theory, and, more recently, robotics. This review paper focuses on one trend of power system monitoring, namely, mobile monitoring. The developments in robotic maintenance for power systems indicate significant potential of this technological approach. Authors discuss integration of several important relevant sensor technologies that are used to monitor power systems, including acoustic sensing, fringing electric field sensing, and infrared sensing.

Robotic platform for monitoring underground cable systems

Accurate, real-time information about the aging status of the power distribution cable network can save the power industry millions of dollars lost due to line failures and premature replacement of cables. Hence, a novel, semi-autonomous robotic sensor platform has been developed for monitoring underground, power distribution cable systems. A segmented, legged modular configuration allows the robot to traverse cables with a diameter of four to eight centimeters and negotiate obstacles along its path. The design of platform consists of a multi-processor control board, a 900 MHz wireless communication module, and infrared, dielectrometry, and acoustic sensors. The robot is capable of fully autonomous operation or human tele-operation via a LAN or Internet connection. A prototype platform has been developed and tested with a 14 kV distribution cable. Currently, sensor integration is underway.

Mobile monitoring for distributed infrastructures

Efficient maintenance of distributed infrastructures requires accurate and up-to-date information to ensure reliable service. Existing monitoring techniques commonly rely on either data collected at scattered points or on costly manual inspection of suspect components by service personnel. Implementation of mobile robots for continuous autonomous monitoring of these infrastructures can provide a cost-effective means of gaining accurate information for maintenance planning. This paper offers a discussion on key system-level issues that must be addressed in any mobile monitoring project. These issues include: (a) economic analysis of incorporating mobile robotics into existing maintenance strategies, (b) the ability of the autonomous robot to negotiate diverse and unstructured environment, and (c) the feasibility of integrating needed sensors into a robotic platform. The example application examined in this paper is an autonomous robotic platform that monitors underground power cables for incipient failures.