Jonathan Jingsheng Shi

Implementing integration of ISO 9001 and ISO 14001 for construction

Purpose – The aim of this study is to evaluate implementation of an integrated management system (IMS) based ISO 9001 and ISO 14001 standards for construction firms.Design/methodology/approach – Supported by a structured questionnaire survey, this paper examines several related issues in the implementation of IMS in construction firms in China. The researchers interviewed the auditors of ISO 9001 and ISO 14001 standards and senior managers of ten construction firms. The structured questionnaires were sent to 300 construction firms in China. Among them, 68 completed questionnaires were received.Findings – The findings reveal that a majority of the firms support an integration of the ISO 9001 and ISO 14001 standards. “Similarity” and “compatibility” between the two standards are considered as the main reasons for pursuing such an integration. The benefits resulted from the integration include “avoidance duplication of procedures”, “reduced conflict of procedures”, and “reduced requirements for resources”. T...

A neural network based system for predicting earthmoving production

An artificial neural network based system (NN earth) is developed for construction practitioners as a simple tool for predicting earthmoving operations, which are modelled by back propagation neural networks with four expected parameters and seven affecting factors. These networks are then trained using the data patterns obtained from simulation because there are insufficient data available from industrial sources. The trained network is then incorporated as the computation engine of NN earth. To engender confidence in the results of neural computation, a validation function is implemented in NN earth to allow the user to apply the engine to historic cases prior to applying it to a new project. An equipment database is also implemented in NN earth to provide default information, such as internal cost rate, fuel cost, and operators cost. User interfaces are developed to facilitate inputting project information and manipulating the system. The major functions and use of NN earth are illustrated in a sample application. In practice, NN earth can assist the user either in selecting a crew to minimize the unit cost of a project or in predicting the performance of a given crew.

Revisiting the relationship between environmental and financial performance in Chinese industry.

The debate on the relationship between corporate or industrial environmental performance (EP) and financial performance (FP) has yet to be resolved, and studies need to examine the possible moderating effects on the EP-FP link. We argue that industrial EP has a positive effect on FP and that industrial munificence and resource slack can moderate the EP-FP link. Using a dataset from Chinese industrial firms, we examine the direct effect of industrial EP on FP and the indirect effects of industrial munificence and resource slack on the EP-FP link. Our results show that improving corporate or industrial-level EP significantly influences FP and that slack resources play a significant role on the EP-FP link. However, we found no significant moderating effect of industrial munificence on the link.

Adaptive photovoltaic system

This paper discussed a new photovoltaic (PV) system topology that uses PV energy in efficient way in order to improve system power output during different operating conditions. The proposed topology provides flexible connection between PV modules to achieve different configurations of PV array. A new switching matrix has been developed to achieve the required configurations. Preliminary simulations provide promising results for an adaptive PV array. Comparison between traditional PV system configurations and adaptive configuration is considered. A significant improvement in power curves is achieved by the proposed topology.

Visual modeling and simulation for construction operations

Simulation practitioners in construction often experience difficulties in developing simulation models, i.e., tediousness and error-proneness. The visual environment presented in this paper gives users user-friendly support throughout the entire simulation development process, with the provision of a visual modeling interface, easy-to-use icon animation, and dynamic statistics. Under the visual modeling interface, modeling construction operations is completed through editing activity-based graphics as the standard graphic editing tools do, and no programming is required. An easy-to-use animation can facilitate communication between the simulation model and users, and assist users in verification and validation of the simulation model. Instead of creating 3-D images with adequate skills and much time, this animation takes the graphic simulation model as the background images and the pre-created 2-D iconic images as moving objects, in order that the preparing for animation is simple.

Enhancing the logistics of construction materials through activity‐based simulation approach

Purpose – Many planners and managers prefer to maintain more than enough construction materials on site to avoid valuable labour and plant resources staying idle. Despite the fact that minimising the buffer stock would improve the productivity of a construction project, no one likes to take this risk especially when the consequences are not totally clear. This paper aims to identify the possible savings in time and cost due to different amounts of buffer stock on site, by introducing an activity‐based simulation model.Design/methodology/approach – In this research, details and data of a residential project involving substantial amounts of pre‐cast components are collected. The project participants are asked to unveil the constraints on site and throughout the material delivery and storage processes. Finally, the collected data are fed into the activity‐based construction simulation tool for analysis.Findings – The results indicate that simulation could help quantify the productivity of resources so as to ...

Iconic animation of construction simulation

Presents a continuous research effort concerning the animation function in the development of the Activity-Based Construction (ABC) modeling and simulation system. ABC animation uses the constructed ABC simulation model as the animation background, and pre-created images of the simulation entities move around along individual execution paths on the ABC model. A library of icons consisting of common construction entities has been created in the ABC system. To perform the animation function in ABC only involves one simple additional task for the user: to select an appropriate icon for a simulation entity.

An AHP-weighted aggregated data quality indicator (AWADQI) approach for estimating embodied energy of building materials

PurposeAggregated data quality indicator (ADQI) method has been used to estimate probability distributions of the input data in a life cycle assessment (LCA) to compensate for insufficient data in a statistical analysis. In a traditional ADQI, a multicriteria evaluation process, the impacts of various quality indicators under investigation are often equally weighted or unweighted despite the fact that some of them may weight more than the others on contributing to the overall data uncertainty. An unweighted ADQI (UWADQI) approach, though simple, may lead to incorrect conclusions. This paper aims to develop a weighted ADQI to overcome the deficiency of the unweighted ADQI to make it more reliable for LCA uncertainty analysis.MethodTo improve the UWADQI approach, an analytical hierarchy process (AHP) is introduced in this research for estimating weighting factors in the ADQI aggregation process. An AHP’s pairwise comparison function is used to determine the weighting of each data quality indicator. Three common building materials of concrete, steel, and glass were chosen to validate the presented method.Results and discussionUsing the published results from the statistical method as the benchmarks, it was found that the proposed AHP-weighted ADQI (AWADQI) method lead to better estimated probabilistic values of embodied energy intensity than the traditional UWADQI approach for the three building materials.Conclusions and recommendationsIn conclusion, using AHP to incorporate weighing factors into an ADQI process can improve the uncertainty estimate of embodied energy of building materials, and consequently, the method can improve the reliability of a building LCA.

Simulation-based methodology for project scheduling

This paper describes a discrete-event simulation that incorporates the critical path method (CPM) in generating comprehensive information for construction project scheduling or planning. An activity-based graphical model able to consider complexities in construction, for example, unbalanced logical dependencies, unbalanced resource involvements and repetitive activity operation is proposed. An activity scanning (AS)-based forward pass algorithm for early-time information and a backward search algorithm for late-time information are developed. The simulation results that include both resource utilization statistics and late-time information (i.e. latest start or finish time and total float (TF)) of every activity for each cycle of operation cannot be easily achieved through traditional simulation or CPM. Illustrations demonstrate the advantages of the activity-based graphical model and the impacts of resource allocation policies on the schedule. The proposed methodology aims at widening the application of construction simulation by providing float time information and enhanced modelling capability.

Three methods for verifying and validating the simulation of a construction operation

A simulation model must be verified to confirm that it describes correctly its intended real world process under study; moreover, the simulation results obtained must be a valid representation of the process. This study presents three activity-based white-box methods for assisting a user in verifying and validating construction simulations. The first method reports a simulation by listing all activities in the chronological order of their executions, so that a user can contrast the simulated progress against the actual progress in the real world. The second method summarizes the operating counts and mean durations of all activities over the simulated time period, to enable a user to evaluate whether all activities have been executed correctly during simulation. The third method generates an activity cycle report for any selected resource entity, so that a user can examine whether the entity is moving in the correct logical and chronological order during simulation. The three methods can be used jointly to debug a simulation model, so as to confirm that the simulation is correctly conducted and the obtained results are valid. The three methods are implemented in a simulation system in the form of corresponding reports. A concreting process is employed to illustrate these methods.