Ubiquitous location tracking for context-specific information delivery on construction sites

Construction projects are information-intensive in nature and require site personnel to have continuous on-demand access to information such as project plans, drawings, schedules, and budgets. Awareness of a user's context (such as user profile, role, preferences, task, and existing project conditions) can enhance the construction project delivery process by providing a mechanism to determine information relevant to a particular context. Context awareness can also be used to improve security, logistics and health and safety practices on construction sites. Location is an important aspect of context awareness. A location aware application can utilize the knowledge of the user/object location to provide relevant information and services. This paper argues that a successful and reliable location tracking system must be able to track a user's spatial context and deliver contextual data continuously in both outdoor and indoor environments to effectively support construction projects. Research describing the use of Wireless Local Area Network (WLAN) for indoor tracking and Global Positioning System (GPS) for outdoor spatial context tracking is presented, and an integrated tracking technique using WLAN and GPS for ubiquitous location sensing is introduced. The key benefits and technical challenges of such an integrated approach are also highlighted. The presented tracking techniques have been validated in both indoor and outdoor environments to ensure their practical implementation on real construction jobsites.     

Static and dynamic performance evaluation of a commercially-available ultra wideband tracking system

Locating and tracking resources (e.g., people, equipment, and materials) is critical in many industrial applications for monitoring productivity and safety. In construction, various technologies (e.g., global positioning systems (GPS), radio frequency identification (RFID) and radio frequency (RF) localization) have been proposed. However, the performance of these types of technologies is not well understood for this particular application. This paper presents a study for evaluating the static and dynamic performance of a commercially-available ultra wideband (UWB) tracking system in free space and under realistic construction environments. In addition, a static performance model for estimating position error as a function of receiver position and initial calibration error was also developed. Results and experiences are in particular useful for researchers or practitioners in need for adapting UWB technology for their application.     

Location tracking and data visualization technology to advance construction ironworkers' education and training in safety and productivity

Most construction worker education and training environments apply traditional teaching methods to educate workers about hazards and productivity in the workplace. Many rely on using conventional teacher–student classroom settings, but there are few effective interactive methods applied which can objectively engage trainer and trainees and assess their performance during and after training sessions. Presented is a novel approach towards integrating real-time location tracking and three-dimensional immersive data visualization technologies in existing construction worker education and training environments. The scope is limited to steel-erection tasks performed by union ironworkers in an indoor training center. Results to analysis and visualization of the gathered data from training session are shown. The potential for assessing and improving the trainers' and apprentices' safety and productivity performance is explained. Since such technologies have hardly been used as part of existing construction education and training techniques, the opportunities including return on investment and user feedback were studied. The results show that unsafe practices in worker training environments can be detected and visualized and furthermore their training effectiveness can be indirectly measured.     

Performance evaluation of ultra wideband technology for construction resource location tracking in harsh environments

Emerging wireless remote sensing technologies offer significant potential to advance the management of construction processes by providing real-time access to the locations of workers, materials, and equipment. Unfortunately, little is known regarding the accuracy, reliability, and practical benefits of an emerging technology, effectively impeding widespread adoption. This paper evaluates a commercially-available Ultra Wideband (UWB) system for real-time, mobile resource location tracking in harsh construction environments. A focus of this paper is to measure the performance of the UWB technology for tracking mobile resources in real-world construction settings. To assess tracking accuracy, location error rates for select UWB track signals are obtained by automatically tracking a single entity using a Robotic Total Station (RTS) for ground truth. Furthermore, to demonstrate the benefits of UWB technology, the paper provides case studies of resource tracking for analysis of worksite operations. The work demonstrates the applicability of UWB for the design of construction management support tools.     

Wireless networking in tunnelling projects

Emerging collaborative technologies and working methods often require tremendous engineering and organisational efforts for successful implementation of information and communication technologies (ICTs). According to a research conducted in Turkish construction industry, most of the problems that occur during the construction phase are due to lack of co-operation and communication between designers and contractors and lack of prompt expert decisions during on-site engineering. Similar to any major construction project, tunnelling project’s success is highly dependent on collaborative team work where communication and information exchange take place between project members. Distributed collaborative teamwork, as the case in most of the large scale construction projects as well as tunnelling projects, empowered by state of the art information and communication technology, promises more efficient work processes, reduced travelling needs, and increased opportunities for project communication. Following the fast development of mobile computing in recent years, many sectors have adopted mobile devices and wireless technologies enabling real-time information transfer thereby improving business processes. For some years, the feasibility of implementing wireless solutions to construction sites has been researched. Potentially, mobile and wireless technologies enable construction staff to be more flexible in terms of location and time. For better use of mobile collaboration in construction projects, mobile technologies and construction sector have to be examined in some detail to implant the most suitable technology for real-time information access and improved collaboration of distributed teams in construction. However, case studies in construction are very limited in number and scope. This paper discusses and proposes an implementation scenario of wireless networking in Marmaray; a multi-site tunnelling project in Istanbul. Benefits, possible problems and cost assessments are discussed.     

RFID indoor location identification for construction projects

This paper presents a low cost indoor location identification and material tracking methodology for construction projects using Ultra High Frequency (UHF) passive Radio Frequency Identification (RFID) technology. Onsite location aware information is an emerging area that focuses on automating delivery of spatial information pertinent to location of materials, workforce, and equipment. This spatial information can be used to derive knowledge about construction project status. A two-step algorithm is presented to automate the process of location estimation and material tracking in near-real-time. In this methodology, a number of passive RFID tags are distributed onsite where work is progressing, and a mobile RFID reader is carried by a worker onsite. Each passive RFID tag is deployed as a reference point with a known location (landmark) within a predefined zone. Reference tags of known locations are used to determine the location of the worker and eventually locate and track surrounding materials. The methodology uses Received Signal Strength Indicator (RSSI) for signal measurements. Two localization methods (triangulation and proximity) were used to identify the location of the worker. Testing this methodology was carried out on an actual construction jobsite, where five test beds were setup at different locations and within different construction time spans. In addition, one test bed was set up in a lab environment. The results presented in this study demonstrate the potential for a low-cost method for location estimation and material tracking of indoor construction. The results show a mean error of 1.0 m and 1.9 m for user location identification and material tracking using the triangulation method, respectively. The results also show a mean error of 1.9 m and 2.6 m for location identification of the worker and for material tracking using the proximity method, respectively. The proposed methodology detects the zones of worker and material location with 100% accuracy.     

Application of WiFi-based indoor positioning system for labor tracking at construction sites: A case study in Guangzhou MTR

For construction management, tracking the locations of construction resources such as labor, materials machinery, and vehicles is important. Some alternative form of location monitoring system is necessary for indoor environments such as tunnels and buildings under construction, because of systematic limitations of the Global Positioning System (GPS). This study investigated the feasibility of a WiFi-based indoor positioning system for construction sites. The system was developed using the fingerprint method of Received Signal Strength Indication (RSSI) from each Access Point (AP). A series of experiments were conducted at a shield tunnel construction site in Guangzhou, China. The results showed that the WiFi-based indoor positioning system was accurate within 5 m of error for that site, thus proving the utility of the system for tracking the approximate locations of labor at construction sites. Additionally, this system could be used for monitoring the locations of other construction resources such as vehicles and materials.     

Simulation of Accuracy Performance for Wireless Sensor-Based Construction Asset Tracking

Abstract:   Today's mobile and remote construction applications, such as tracking of materials, equipment, and workers, demand high reliability and scalability of wireless sensor networks for a large-scale construction site. In particular, identifying the location of distributed mobile entities throughout wireless communications becomes the primary task to realize the remote tracking and monitoring of the construction assets. Even though several alternative solutions have been introduced by utilizing recent technologies, such as radio frequency identification (RFID) and the global positioning system (GPS), they could not provide a solid direction to accurate and scalable tracking frameworks in large-scale construction domains due to limited capability and inflexible networking architectures. This article introduces a new tracking architecture using wireless sensor modules and shows an accuracy performance using a numerical simulation approach based on the time-of-flight method. By combining radio frequency (RF) and ultrasound (US) signals, the simulation results showed an enhanced accuracy performance over the utilization of an RF signal only. The proposed approach can provide potential guidelines for further exploration of hardware/software design and for experimental analysis to implement the framework of tracking construction assets.     

Color tracking for multiple robot control using a system-on-programmable-chip

A new trend in construction is the emerging technologies to accommodate personal indoor robots moving among occupants and assisting them. In many circumstances, the coordination of multiple robots is required for task execution, whereby it is important to cooperatively control robots to navigate in a desired formation. For this, real-time information of each robot's location can be made available via the use of computer vision technologies. This paper presents the development of a digital camera surveillance system that can track color tags of moving robots in an indoor environment. The system, which comprises image demosaicking, color detection, relative distance estimation and moving object tracking, is designed for controlling a number of miniature robots, utilizing the system-on-programmable-chip technology. Here, essential issues of real-time computation and low power consumption are simultaneously resolved with register-transfer level and gate circuits. Experimental results are provided for verification. An emphasis is given to construction applications.     

Error modeling for an untethered ultra-wideband system for construction indoor asset tracking

This paper analyzes the performance of an ultra-wideband (UWB) wireless network system for mobile asset tracking at a dynamic construction site. Static and dynamic error tests were performed on a commercial UWB system in different building spaces including open/closed spaces, steel/wood framed construction sites, and a closed office area. All tests were carried out with an untethered UWB configuration for more flexible deployment of the UWB system at construction sites. Statistical approaches including regression analysis, outlier detection, and Kalman filtering were used to build an error model. The research found that each site has a unique pattern of producing errors caused by various types of interference, e.g., electromagnetic interference, multi-path propagation, fading and scattering of signals. Approximately 25% of the errors were reduced by using the proposed error modeling process. The paper concludes that a statistically developed error model process can significantly reduce random errors and improve position accuracy for indoor mobile asset tracking applications in construction.     

Prompt tracking of indoor airborne contaminant source location with probability-based inverse multi-zone modeling

Indoor air quality (IAQ) has a significant influence on occupants' comfort, health, productivity, and safety. Existing studies show that the primary causes of many IAQ problems are various airborne contaminants that either are generated indoors or penetrate into indoor environments with passive or active airflows. Accurate and prompt identification of contaminant sources can help determinate appropriate IAQ control solutions, such as, eliminating contaminant sources, isolating and cleaning contaminated spaces. This study develops a fast and effective inverse modeling method for identifying indoor contaminant source characteristics. The paper describes the principles of the probability-based adjoint inverse modeling method and formulates a multi-zone model based inverse prediction algorithm that can rapidly track contaminant source location with known source release time in a building with many compartments. The paper details the inverse modeling procedure with modification of an existing multi-zone airflow and contaminant transport simulation program. The application of the method has been demonstrated with two case studies: contaminant releases in a multi-compartment residential house and in a complex institutional building. The numerical experiments tested the source identification capability of the program for various contaminant sensing scenarios. The investigation verifies the effectiveness and accuracy of the developed method for indoor contaminant source tracking, which will be further explored to identify more complicated indoor contamination episodes.     

Using reference RFID tags for calibrating the estimated locations of construction materials

Effective automated tracking and locating of the thousands of materials on construction sites improve materials management and project performance. Utilizing location sensing technologies such as RFID, GPS, Ultra-wideband, infrared, and others help to achieve this objective; however, they generally provide imperfect data which results in lack of accuracy, precision and robustness. One possibility of improving the precision, accuracy, and robustness of such systems is the use of reference tags. In this paper active RFID tags are employed as reference points at known and fixed locations on a construction site and are used to calibrate the location estimation of other materials on the site. Materials on the site are uniquely attached with RFID tags and are subject to tracking. The basic principle of the calibration technique using reference points is to adjust the estimated location of neighboring tags by adding a unique offset vector to each individual tag location-estimation. In a two level approach, first the locations of all tags are estimated using a proximity method. Then a unique offset vector is calculated and added to each individual tag location to calibrate the estimated location in level 1. The offset vector is a weighted average of the shift-vectors between the observed and the true location of the reference tags. The weights are based on the relative distance between the observed location of the target tag and the reference tags. The experimental results show that calibrating the location estimates using reference tags can successfully deal with the challenges of a very noisy and dynamic environment and imperfect construction data and improve the precision of the estimated locations.     

Construction quality management based on a collaborative system using BIM and indoor positioning

Quality is one of the most vital aspects of a construction project, and inspection is the most important task in construction quality management. Despite the application of advanced information technologies, the omission of check items and in-efficiency of entering inspection results from paper-based inspection records into computers and collaboration among the construction stakeholders remain to be major problems. This paper proposes an approach to make the process of construction quality management more effective and collaborative by developing a system based on the integrated application of building information modeling (BIM) and indoor positioning technology. First, the system requirements of the collaboration platform are analyzed based on the standards for construction quality inspection in China, the technologies to be used for its implementation are justified, and a process model for the collaboration of multiple stakeholders is established. Next, the system architecture is developed, and the algorithm for generating inspection tasks and the technique for integrating with indoor positioning technology are formulated. Finally, the implementation of a prototype system is presented, and the effectiveness and efficiency of the approach for construction quality management are verified by using the system in an on-site test.     

Environmental influences on indoor walking behaviours of assisted living residents

Regular walking behaviours can improve older people's physical, psychological and social health. This project examined the relationships between assisted living facilities’ design features and residents’ indoor walking behaviours through surveys and field evaluations. Surveys were conducted in 18 assisted living facilities in the US state of Texas. Researchers gathered information from 343 residents about their walking behaviours, participation in other activities, health and demographic status, and perceptions of the environment. Field evaluations were conducted to collect objective physical environment measures. Facility information was provided by the administrators. Multivariate hierarchical regression analysis showed significant influences of physical environments on indoor walking behaviours. Indoor recreational walking was related negatively to the number of stories of the building and positively to the perception of looped corridors. Different types of utilitarian walking, such as ‘walk to other activities’, ‘walk to front entry' and ‘walk to mailbox' were influenced by specific design features. The number of utilitarian walking types was marginally influenced by the number of stories of the building. These findings will help inform the design of activity-friendly assisted living facilities and the creation of health promotion programmes for frail older people.     

Utilization analysis methodology for fleet telematics of heavy earthwork equipment

Fleet telematics aims to comprehensively control equipment groups through location tracking, maintenance control, and productivity monitoring of individual equipment based on real-time location and status transmitted to fleet control center from the equipment. Logistics industry, automobile industry, as well as transportation (land, sea, and air) industry are actively applying fleet telematics in order to efficiently and safely operate multiple groups of equipment. Earthwork, a basic operation for any type of construction, depends heavily on equipment. The productivity and safety of earthwork equipment are decided by effective management of the equipment. Therefore, fleet telematics can also improve the earthwork operation as well. The goal of this research is to develop a GPS only-based fleet telematics system for heavy earthwork equipment which can analyze time log information of each equipment using GPS location data without utilizing any other on-board sensors and CAN bus data. The earthwork site (loading and dumping area) and moving route, hazardous areas of the project are all visualized on a map via geo-fencing technology considering the characteristics of earthwork operation. Lastly, algorithms to analyze the utilization time of earthwork equipment using GPS location information are designed and their reliability are verified through field tests.     

Forward‐Backward Approach for 3D Event Localization Using Commodity Smartphones for Ubiquitous Context‐Aware Applications in Civil and Infrastructure Engineering

An inexpensive and robust 3D localization system for tracking the position of a user in GPS‐ or WLAN‐denied environments offers significant potential for improving decision‐making tasks for civil and infrastructure engineering applications. To this end, an infrastructure‐free approach for 3D event localization on commodity smartphones is presented. In the proposed method, the position of the user is continuously tracked based on the smartphone sensory data (the Forward approach) until the user reaches a certain event. Here, an event location refers to the 3D location of a user conducting value‐added activities such as tasks involved in emergency response and field reporting of operational issues. Once an event is observed, the motion trajectory of the user is backtracked from the postevent landmark to reestimate the location of the event (the Backward approach). By integrating probability distributions of the Forward and Backward approaches together, the proposed method derives the most‐likely location of the event. To validate the proposed approach, seven case studies are conducted in a multistory parking garage. The experimental results show that the probabilistic integration of the localization results from the Forward and Backward dead reckonings can produce more accurate 3D localization results when compared to a single best estimate from a one‐way dead reckoning process. Lessons learned from several real‐world case studies and open research challenges in improving localization accuracy are discussed in detail.     

基于GIS/GPS的建筑机械远程管理系统

本文讨论了GIS和GPS在建筑机械远程在线管理中的应用。以嵌入GIS功能的Visual Basic作为开发语言，通过采集到的远程设备数据，对整个设备群进行在线位置和状态参数的显示和集中监控调度。GPS信息处理和数据采集由车载计算机完成，使建筑机械从静态管理发展到实时的动态管理。     

Mobile Construction Supply Chain Management Using PDA and Bar Codes

Abstract:   Construction project control aims to effectively obtain real-time information and enhance dynamic control by utilizing information sharing and connecting involved participants of the projects to reduce construction conflicts and project delays. However, extending the construction project control system to job sites is not considered efficient because using notebooks in a harsh environment like a construction site is not particularly a conventional practice. Meanwhile, paper-based documents of the site processes are ineffective and cannot get the quick response from the office and project control center. Integrating promising information technologies such as personal digital assistants (PDA), bar code scanning, and data entry mechanisms, can be extremely useful in improving the effectiveness and convenience of information flow in construction supply chain control systems. Bar code scanning is appropriate for several construction applications, providing cost savings through increased speed and accuracy of data entry. This article demonstrates the effectiveness of a bar-code-enabled PDA application, called the mobile construction supply chain management (M-ConSCM) System, that responds efficiently and enhances the information flow between offices and sites in a construction supply chain environment. The advantage of the M-ConSCM system lies not only in improving the efficiency of work for on-site engineers, but also providing the Kanban-like visual control system for project participants to control the whole project. Moreover, this article presents a generic system architecture and its implementation.     

Mobile 3D mapping for surveying earthwork projects using an Unmanned Aerial Vehicle (UAV) system

Unmanned Aerial Vehicle (UAV) systems as a data acquisition platform and as a measurement instrument are becoming attractive for many surveying applications in civil engineering. Their performance, however, is not well understood for these particular tasks. The scope of the presented work is the performance evaluation of a UAV system that was built to rapidly and autonomously acquire mobile three-dimensional (3D) mapping data. Details to the components of the UAV system (hardware and control software) are explained. A novel program for photogrammetric flight planning and its execution for the generation of 3D point clouds from digital mobile images is explained. A performance model for estimating the position error was developed and tested in several realistic construction environments. Test results are presented as they relate to large excavation and earth moving construction sites. The experiences with the developed UAV system are useful to researchers or practitioners in need for successfully adapting UAV technology for their application(s).