R.N. Rustom and A. Yahia
Recently, there has been increased interest in the use of simulation for real‐time planning, scheduling, control of construction projects and obtaining optimum productivity. The…
Abstract
Purpose
Recently, there has been increased interest in the use of simulation for real‐time planning, scheduling, control of construction projects and obtaining optimum productivity. The purpose of this case study is to demonstrate the use of simulation as an effective tool for estimating production rates in an attempt to prepare optimal time schedules.
Design/methodology/approach
Gaza Beach‐Camp Shore Protection Project was taken as a case study. The case study is used to demonstrate how to estimate effectively the production rates of labour and equipment during the implementation of the project activities and to estimate the duration of the project using process simulation. The model simulates the construction of 1,600 m of gabions divided into 32 identical stations. Probabilistic distribution functions were used to fit the time functions for each process and sub‐process based on 100 replications.
Findings
The simulation output generated three probabilistic values for completing each activity upon which the overall project completion time is determined. The resources utilizations for all processes were also generated and used in the determination of the average production rates.
Originality/value
The computation of productivity based on effective resources utilization has been demonstrated to give better results than estimating productivity based on aggregate resources assignments.
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Md. Ikramul Hoque and Muzamir Hasan
Quality is a sensitive and high-priority issue in the global construction including in Bangladesh. This research is intended to provide necessary information to stakeholders and…
Abstract
Purpose
Quality is a sensitive and high-priority issue in the global construction including in Bangladesh. This research is intended to provide necessary information to stakeholders and authorities for better management of the construction quality in Bangladesh. Therefore, this study seeks to find and prioritize the factors affecting the construction quality in Bangladesh.
Design/methodology/approach
In total 65 factors were extracted and categorized from the literature and expert panel discussion. Subsequently, these factors were designed in a questionnaire under 13 major groups for a survey where 176 construction professionals participated and returned their completed survey form. Collected data were tested by the Cronbach Alpha to check the reliability before proceeding to the Relative Importance Index (RII) analysis for determining the relative ranks of identified factors.
Findings
Statistical analysis of survey data represents that the most significant factors are: lack of management commitment, lack of technical skill and experience of the consultant, delays in progress investigation, political interference and contractor's desire for unrealistic profit. The most crucial major groups of factors influencing the construction quality are management, material, consultant, cost and time and contract-related major groups.
Originality/value
It will contribute to the body of knowledge, as it points out the impact of factors affecting quality in Bangladeshi construction. Authorities and stakeholders can be helped by the overview of the high and low ranks factors, understanding the diverse characteristics of factors and making more aware the industry about the quality issues which need to be a top concern to solve. Other developing countries that share the same socio-economic context as Bangladesh can be benefit from the results of this study to control quality issues in construction.
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The paper aims to provide a structured framework for comparing different productivity estimation methodologies and evaluate their sensitivity to operational coefficients variation…
Abstract
Purpose
The paper aims to provide a structured framework for comparing different productivity estimation methodologies and evaluate their sensitivity to operational coefficients variation for excavation operations.
Design/methodology/approach
Two process‐oriented methodologies were analysed in a deterministic fashion in terms of their input requirements and their respective outputs. A phase‐oriented framework was presented to enable their comparison. The research methodology allows the estimation of excavation productivity in relation to the selected operational coefficients.
Findings
The system productivity is significantly influenced by operational conditions, such as the digging depth and the swing angle from the excavation front to the dumping position. Each methodology presents a differing sensitivity to every operational factor. Since the excavator is considered as the system's leading resource, the variation on productivity has direct implications for the truck fleet size and the unit cost of operations.
Originality/value
The proposed approach is useful in analyzing process‐oriented productivity estimation methodologies under a given set of operational coefficients when no historical data is available. Thus, it provides an alternative to intuitive estimates based solely on personal judgment. The concept of “baseline reference” conditions is introduced, so as to enable the transformation of any operational scenario into equivalent mathematical models that allow comparisons between different estimation methodologies and computational approaches.
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Bao Pham Van and Vachara Peansupap
Construction material management is an important process in supporting construction operations that affect project performance. Previous studies attempt to identify factors…
Abstract
Purpose
Construction material management is an important process in supporting construction operations that affect project performance. Previous studies attempt to identify factors influencing material management in different stages such as procurement, transportation and utilization. However, they lack a model to explain the relationship between influential factors and the effectiveness of material management. Therefore, this study aims to validate the variables and key factors influencing the effectiveness of material management processes.
Design/methodology/approach
A total of 42 variables were reviewed from literature in different stages of material management process. Survey questionnaires were used to collect data about participants' perceptions on these variables. The respondents were 200 project engineers and project managers from construction sites and offices in Vietnam. Then factor analysis techniques were undertaken to validate the structure of factor groups. Two methods of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were, respectively, performed to evaluate and verify the model's fit.
Findings
Factors influencing the effectiveness of material management were grouped into nine main factors, which are procurement issues, site conditions, planning and handling on site, industrial environments, contractual issues, quality control, suppliers and manufacturers' issues, transportation in and out site and security on site.
Practical implications
The paper has several implications for theory and methodology related to material management. It features influential factors in association with the material management effectiveness. Therefore, senior managers can more fully understand the errors in their works and propose timely solutions to limit the unwanted risks.
Originality/value
This research contributes on theoretical development on factors influencing effectiveness of material management processes. The key findings on influential factors can be applied to measure the effectiveness of material management processes.
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This chapter explores the impact of the seemingly new recognition of non-Muslims in Turkey, a historically marginalized minority. In the 2000s, the ruling AKP party, a religiously…
Abstract
This chapter explores the impact of the seemingly new recognition of non-Muslims in Turkey, a historically marginalized minority. In the 2000s, the ruling AKP party, a religiously and socially conservative party, made a number of symbolic gestures toward the increasing recognition of these communities. This chapter explores this ethnographically and historically by looking at the political effects of AKP’s democratization attempts on the Rum Orthodox (“Greek”) community in Istanbul. It argues that these attempts paralleled a similar language of democracy within the community particularly in the aftermath of the government’s permission to run elections in the non-Muslim community institutions (vakıfs), following a period of time during which no elections had been held in these institutions. At the same time, these attempts occasioned old and new forms of hierarchies within the community, which emerged as a result of the competing claims within it to its representation. These seemingly ambiguous effects of democratization within the Rum community emerged in the gap between the AKP’s democracy discourse that claims universal inclusion and its highly selective practice of democracy. This was so because the AKP preserved the ethnoreligious definition of national identity even while it readopted the historical legacies of the Ottoman millet system that managed society along religious confessional lines. These findings contribute to the existing theories on democratization by highlighting the inextricable link between inclusion and exclusion that emerges in the gap between the discursive claims of democracy toward universal inclusion and the selective actualization of these claims in practice. Such selective inclusion that is inherent to the politics of democracy is managed differently in different contexts due to the hybrid forms of state recognition of the population.
Nabil El‐Sawalhi, David Eaton and Rifat Rustom
This paper seeks to introduce an evolved hybrid genetic algorithm and neural network (GNN) model. The model is developed to predict contractor performance given the current…
Abstract
Purpose
This paper seeks to introduce an evolved hybrid genetic algorithm and neural network (GNN) model. The model is developed to predict contractor performance given the current attributes in a process to pre‐qualify the most appropriate contractor. The predicted performance is used to pre‐qualify the contractors.
Design/methodology/approach
Hypothetical and real‐life case studies from projects executed in the Gaza Strip and West Bank were collected through structured questionnaires. The evaluation of the contractor's attributes and the corresponding actual performance of the contractor in terms of time, cost, and quality overrun (OR) were collected. The weighted contractor's attributes were used as inputs to the GNN model. The corresponding time, cost, and quality ORs for the same cases were fed as outputs to the GNN model in a supervised learning back propagation neural network (NN). (The adopted training and testing process to develop a trained model is presented.) The training process, including choosing the topology of the required NN using genetic algorithms, is explained.
Findings
The results revealed that there is a satisfactory relationship between the contractor attributes and the corresponding performance in terms of contractor's deviation from the client objectives. The accuracy of the model in terms of mean absolute percentage error (MAPE), R2, average absolute error and mean square error revealed that the model has sufficient accuracy for implementation. The average MAPE for time, cost and quality OR is 15 per cent. Consequently, the model accuracy is 85 per cent.
Originality/value
The GNN model is able to predict future contractor performance for given attributes.
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Saad Abdel-Karim El-Hamrawy, Ahmed Ebrahim Abu El-Maaty and Ahmed Yousry Akal
Quality measurement is the trigger for quality improvement. Indeed, what gets measured gets done. The real scope of quality improvement in construction projects is the difficulty…
Abstract
Purpose
Quality measurement is the trigger for quality improvement. Indeed, what gets measured gets done. The real scope of quality improvement in construction projects is the difficulty and-maybe-lack of quality measurement methods. The purpose of this paper is to identify the factors influencing the quality performance of highway projects in Egypt. Furthermore, this paper also contributes to develop models to measure the quality level of these projects.
Design/methodology/approach
A literature review is conducted to compile a list of factors influencing the quality of highway projects. The resulting list of factors is subjected to a questionnaire survey which was sent to owners, consultants and contractors of highway projects in Egypt. Furthermore, linear regression analysis and statistical fuzzy approaches are adopted for modeling process.
Findings
The survey results show that availability of experienced staff in the owner’s and contractor’s teams during the project execution, asphalt quality and type used in the construction process, pavement is not designed according to the regional conditions, and contractor’s labors and equipment capability are among the most important factors influencing quality performance.
Originality/value
The main contribution of this study is to develop models to measure the quality of highway projects in Egypt. The first model is based on the linear regression analysis, while the second one is based on a statistical fuzzy approach which is a hybrid approach from the fuzzy logic and regression analysis. Validation of the models reveals that the linear regression and the statistical fuzzy models can accurately assess expected quality of any future highway projects at confidence levels 68.97 and 87.44 percent, respectively.
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Examines a definition of hotels and the number of hotels in thecountries of the UK. Indicates by country the proportions of hotel stockrepresented by the major grading schemes and…
Abstract
Examines a definition of hotels and the number of hotels in the countries of the UK. Indicates by country the proportions of hotel stock represented by the major grading schemes and guides. Analyses the schemes by number and quality of grade where appropriate, and each category by its share of the country′s hotel stock. Explains the difficulties of comparison between grades of different schemes, concluding that a percentage share of grades should be employed. Indicates with equivalence tables percentage shares of quality grades for the major comparable schemes. Concludes that although the numerical comparisons can be criticized because of minor differences in the schemes, a foundation is provided for more meaningful comparisons than has previously existed.
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Spiritual tourism has recently been accepted as a growing segment of tourism in business and research circles. The purpose of this paper is to suggest a new dimension in Islamic…
Abstract
Purpose
Spiritual tourism has recently been accepted as a growing segment of tourism in business and research circles. The purpose of this paper is to suggest a new dimension in Islamic marketing and investigates spiritual tourism as a new strategy for marketing Islam as a religion.
Design/methodology/approach
In this exploratory research, convenient sampling was employed to select Muslim spiritual tourists and Islamic organisations arranging spiritual tourism in Australia. A total of 34 face‐to‐face interviews were conducted. Thematic analysis was used to identify factors relevant to the research themes regarding spiritual tourism and marketing Islam.
Findings
Some religious organisations used religious gatherings and festivals as spiritual tourism products to market their religion – Islam. These organisations attracted Muslim and non‐Muslim spiritual tourists to the Islamic places, gatherings, occasions, and festivals by promoting them as spiritual tourism products.
Practical implications
The paper identifies spiritual tourism journeys and events that could be strategically used by religious organisations for marketing Islam.
Social implications
This paper aims to build bridges for better understanding of Islam among the Australian public. The paper could be replicated to study the marketing of other religions in other geographical locations.
Originality/value
The paper originates in recognising a genuinely new strategy of spiritual tourism that could be used more effectively for marketing Islam. A future quantitative study could be conducted to test the findings of this paper.
Andrej Simeunović and David John Hoelzle
The purpose of this study is to develop nonlinear and linearized models of DW printing dynamics that capture the complexity of DW while remaining integrable into control schemes…
Abstract
Purpose
The purpose of this study is to develop nonlinear and linearized models of DW printing dynamics that capture the complexity of DW while remaining integrable into control schemes. Control of material metering in extrusion-based additive manufacturing modalities, such as positive displacement direct-write (DW), is critical for manufacturing accuracy. However, in DW, transient flows are poorly controlled due to capacitive pressure dynamics – pressure is stored and slowly released over time from the build material and other compliant system elements, adversely impacting flow rate start-ups and stops. Thus far, modeling of these dynamics has ranged from simplistic, potentially omitting key contributors to the observed phenomena, to highly complex, making usage in control schemes difficult.
Design/methodology/approach
The authors present nonlinear and linearized models that seek to both capture the capacitive and nonlinear resistive fluid elements of DW systems and to pose them as ordinary differential equations for integration into control schemes. The authors validate the theoretical study with experimental flow rate and material measurements across a range of extrusion nozzle sizes and materials. The authors explore the contribution of the system and build material bulk modulus to these dynamics.
Findings
The authors show that all tested models accurately describe the measured dynamics, facilitating ease of integration into future control systems. Additionally, the authors show that system bulk modulus may be substantially reduced through appropriate system design. However, the remaining build material bulk modulus is sufficient to require feedback control for accurate material delivery.
Originality/value
This study presents new nonlinear and linear models for DW printing dynamics. The authors show that linear models are sufficient to describe the dynamics, with small errors between nonlinear and linear models. The authors demonstrate control is necessary for accurate material delivery in DW.