The capture and integration of construction site data

The use of mobile computing on the construction site has been a well-researched area since the early 1990’s, however, there still remains a lack of computing on the construction site. Where computers are utilised on the site this tends to be by knowledge workers utilising a laptop or PC in the site office with electronic data collection being the exception rather than the norm. The problems associated with paper-based documentation on the construction site have long been recognised (Baldwin, et al, 1994; McCullough, 1993) yet there still seems to be reluctance to replace this with electronic alternatives. Many reasons exist for this such as; low profit margins, perceived high cost; perceived lack of available hardware and perceived inability of the workforce. However, the benefits that can be gained from the successful implementation of IT on the construction site and the ability to re-use construction site data to improve company performance, whilst difficult to cost, are clearly visible. This thesis represents the development and implementation of a data capture system for the management of the construction of rotary bored piles (SHERPA). Operated by the site workforce, SHERPA comprises a wireless network, site-based server and webbased data capture using tablet computers. This research intends to show that mobile computing technologies can be implemented on the construction site and substantial benefits can be gained for the company from the re-use and integration of the captured site data

Facilitating the link between point-of-production workers and corporate ICT systems in construction

Web-based project management systems (WPMS) are becoming more widespread within construction and have shown to be beneficial in improving communications and document transfer between project participants. However, the challenge of integrating point-of-production workers into such systems still remains largely unrealised. This paper describes current applications within construction that are addressing these challenges. The technologies employed vary from tablet PC's, PDA's to RFID tags. The paper examines in detail a web-based data capture and management system for piling works, utilising a site-based web server and wireless network. The system effectively allows for the expansion of existing WPMS to include construction site workers, whilst improving the management and understanding of the project in terms of quality, cost and progress. The paper also agues that improved data reliability and robustness can be achieved by integrating the point-of-production operations into corporate ICT systems

Existence, stability, and dynamics of ring and near-ring solutions to the saturated Gierer--Meinhardt model in the semistrong regime

We analyze a singularly perturbed reaction-diffusion system in the semi-strong diffusion regime in two spatial dimensions where an activator species is localized to a closed curve, while the inhibitor species exhibits long range behavior over the domain. In the limit of small activator diffusivity we derive a new moving boundary problem characterizing the slow time evolution of the curve, which is defined in terms of a quasi steady-state inhibitor diffusion field and its properties on the curve. Numerical results from this curve evolution problem are illustrated for the Gierer-Meinhardt model (GMS) with saturation in the activator kinetics. A detailed analysis of the existence, stability, and dynamics of ring and near-ring solutions for the GMS model is given, whereby the activator concentrates on a thin ring concentric within a circular domain. A key new result for this ring geometry is that by including activator saturation there is a qualitative change in the phase portrait of ring equilibria, in that there is an S-shaped bifurcation diagram for ring equilibria, which allows for hysteresis behavior. In contrast, without saturation, it is well-known that there is a saddle-node bifurcation for the ring equilibria. For a near-circular ring, we develop an asymptotic expansion up to quadratic order to fully characterize the normal velocity perturbations from our curve-evolution problem. In addition, we also analyze the linear stability of the ring solution to both breakup instabilities, leading to the disintegration of a ring into localized spots, and zig-zag instabilities, leading to the slow shape deformation of the ring. We show from a nonlocal eigenvalue problem that activator saturation can stabilize breakup patterns that otherwise would be unstable. Through a detailed matched asymptotic analysis, we derive a new explicit formula for the small eigenvalues associated with zig-zag instabilities, and we show that they are equivalent to the velocity perturbations induced by the near-circular ring geometry. Finally, we present full numerical simulations from the GMS PDE system that confirm the predictions of the analysis

Explicitly solvable nonlocal eigenvalue problems and the stability of localized stripes in reaction-diffusion systems

The transverse stability of localized stripe patterns for certain singularly perturbed two-component reaction-diffusion (RD) systems in the asymptotic limit of a large diffusivity ratio is analyzed. In this semi-strong interaction regime, the cross-sectional profile of the stripe is well-approximated by a homoclinic pulse solution of the corresponding 1-D problem. The linear instability of such homoclinic stripes to transverse perturbations is well known from numerical simulations to be a key mechanism for the creation of localized spot patterns. However, in general, owing to the difficulty in analyzing the associated nonlocal and nonself-adjoint spectral problem governing stripe stability for these systems, it has not previously been possible to provide an explicit analytical characterization of these instabilities, including determining the growth rate and the most unstable mode within the band of unstable transverse wave numbers. Our focus is to show that such an explicit characterization of the transverse instability of a homoclinic stripe is possible for a subclass of RD system for which the analysis of the underlying spectral problem reduces to the study of a rather simple algebraic equation in the eigenvalue parameter. Although our simplified theory for stripe stability can be applied to a class of RD system, it is illustrated only for homoclinic stripe and ring solutions for a subclass of the Giererâ Meinhardt model and for a three-component RD system modeling patterns of criminal activity in urban crime

SHERPA: mobile wireless data capture for piling works

The construction of rotary bored piles uses two interdependent site processes, requiring real-time information sharing between the workforce. This is currently achieved through manual recording of data and calculations on site, which can result in errors in pile construction, delays in the construction program, and additional costs from remedial works. This article describes the Stent Handheld ElectRonic Piling Assistant (SHERPA) which utilizes workforce driven mobile computers accessing a centrally site-located database through a mobile Wireless Local Area Network (WLAN). The WLAN utilizes the IEEE 802.11b protocol for wireless communications, which is becoming increasingly popular in the replacement of traditional wired networks within buildings. However, the application of such technology to construction has been restricted by its use of a wired Ethernet “backbone,” which is impractical for the construction site. This problem has been addressed through the development of Wireless Network Cells (WNCs), which provide a portable and scalable solution to the challenges of implementing mobile networks for real-time data capture in the site environment

Applications of mobile computing for piling operations

The construction of rotary bored piles is a labour intensive process utilising heavy plant and machinery. As-built information for piles is not graphically represented nor can it be easily audited. Presently, it is the responsibility of the workforce to ensure that the pile is constructed to specification and provide as-­built information through manual recording of data on site. Such methods result in non-conformances causing delays and additional costs from remedial works. Stent Foundations Ltd are a major U.K ground improvements contractor, specialising in such work and this paper describes the development of the Stent Handheld ElectRonic Piling Assistant (SHERPA). The system has the potential to improve the quality of piling infor­mation and the knowledge of the workforce. However, this can only be achieved by fully understanding the current working practices and information processes. These are mapped against the available technologies and implementation methods and the proposed solution developed