Jongchul Song

A proximity-based method for locating RFID tagged objects

This paper presents a method intended to extend the use of current radio frequency identification (RFID) technology to tracking the precise location of tagged materials on construction sites. The performance experienced with a commercially available RFID system is compared with the theoretical performance derived from an analytical discrete framework. Also through experimentation, the effects of parameters including RF power, the number of reads, and tag density are assessed, and their performance trade-offs are characterized to suggest guidelines for potential field deployment.

Locating sensor nodes on construction projects

Localization of randomly distributed wireless sensor nodes is a significant and fundamental problem in a broad range of emerging civil engineering applications. Densely deployed in physical environments, they are envisioned to form ad hoc communication networks and provide sensed data without relying on a fixed communications infrastructure. To establish ad hoc communication networks among wireless sensor nodes, it is useful and sometimes necessary to determine sensors’ positions in static and dynamic sensor arrays. As well, the location of sensor nodes becomes of immediate use if construction resources, such as materials and components, are to be tracked. Tracking the location of construction resources enables effortless progress monitoring and supports real-time construction state sensing. This paper compares several models for localizing RFID nodes on construction job sites. They range from those based on triangulation with reference to transmission space maps, to roving RFID reader and tag systems using multiple proximity constraints, to approaches for processing uncertainty and imprecision in proximity measurements. They are compared qualitatively on the basis of cost, flexibility, scalability, computational complexity, ability to manage uncertainty and imprecision, and ability to handle dynamic sensor arrays. Results of field experiments and simulations are also presented where applicable.

Locating materials on construction site using proximity techniques

Construction materials and installed equipment comprise 50-60% of the total cost of a typical industrial project. Tracking the location of construction resources automatically should both improve project performance and enable effortless derivation of performance indicators such as productivity. With recent advances in automated data collection technologies, tracking the location of materials on site has become more viable. A central issue in using these technologies for this purpose is that the existing approaches imply economically prohibitive deployment. This paper presents an approach by which a combination of RFID and GPS technologies may offer the opportunity to densely deploy RFID tags with a few mobile RFID readers equipped with GPS to form the backbone of a construction materials’ tracking system. The findings from preliminary experiments suggest that using this approach, RFID technology may be technically feasible in determining the 2D and ultimately the 3D location of materials on site, when combined with GPS technology. The solution proposed here is intended to extend the use of current RFID technology to tracking the precise movement and location of materials on site, without modifications to current hardware and at a magnitude less cost than pure GPS or other existing approaches.

Field Trials of RFID Technology for Tracking Pre-Fabricated Pipe Spools

The FIATECH Smart Chips project, in conjunction with Shaw Pipe Fabricators and Fluor Corporation, undertook field tests of current RFID technology to determine its technical feasibility for automatically identifying fabricated pipe spools in a laydown yard and tracking shipment through portals. The results indicate the technology could work effectively in the field environment and that it has reached the stage where it can begin to be used to reliably track materials through major portals. Currently, the authors are assessing its potential economic benefits based on preliminary information on recent industrial projects and data provided by the literature.

Thermography-Driven Distress Prediction from Hot Mix Asphalt Road Paving Construction

This research was conducted to assess the effects of temperature segregation in hot-mix asphalt (HMA) paving construction on pavement distress in the early stages of its life cycle. Several paving projects across Nebraska were visited in which sensory devices were used to test how density, moisture content within the asphalt, material surface temperature, internal temperature, wind speed, haul time, and equipment type, contribute to temperature differential. Areas of high temperature differential were identified using an infrared thermal camera. A nonnuclear density device was also used to record how lower temperature asphalt density correlates with a more consistent hot area. The location was marked digitally with a handheld global positioning system to locate points of interest for future site revisits to verify research findings. The research findings indicate that among the investigated variables, truck types and density are highly correlated with temperature differential. Additionally, analysis of data from revisits after one or two freeze-thaw seasons shows that higher temperature differential is significantly correlated with premature distress of paved HMA roads while they are still in new condition. This finding suggests that higher temperature segregation created from paving construction in the zone of freeze-thaw cycles promotes visible surface distress in the very early stage of the pavement life cycle.

Evaluation of Quartz Piezoelectric Weigh-in-Motion Sensors

Quartz piezoelectric weigh-in-motion (WIM) sensors are potentially appealing because of their low sensitivity to temperature fluctuations, according to information gathered from previous installations in other states. These installations also called into question the durability of the quartz sensors. Some sensors stopped producing a signal even though the sensor installation did not exhibit physical distress. After design changes were made, it was necessary to reevaluate the quartz sensor before any major investment in this technology in Texas. This research was undertaken to evaluate the performance and durability of quartz piezoelectric WIM sensors. To perform this evaluation, researchers instrumented two sites with quartz sensors and collected truck weight and sensor condition data to analyze the accuracy and durability of these sensors. The results of this research show that the sensors meet or exceed the weight accuracy specified by the ASTM specification for Type 1 highway WIM systems. The data further show that the truck weights produced by the WIM system are stable over time with minimal variation due to temperature change. There have been no sensor failures or degradation of the installations to date.