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Article
Publication date: 12 March 2018

Jiang Chen, Junli Zheng and Feng Xiong

The spatial resolution of seepage monitoring methods based on fiber Bragg grating (FBG) temperature sensing technology is limited by the distance between measurement…

Abstract

Purpose

The spatial resolution of seepage monitoring methods based on fiber Bragg grating (FBG) temperature sensing technology is limited by the distance between measurement points. Improving the spatial resolution for a given number of measurement points is a prerequisite for popularizing this technology in the seepage monitoring of rockfill dams. The purpose of this paper is to address this problem.

Design/methodology/approach

This paper proposes a mobile-distributed seepage monitoring method based on the FBG-hydrothermal cycling seepage monitoring system. In this method, the positions of the measurement points are changed by freely dragging the FBG sensing cluster within the inner tube of a dual-tube structure, consisting of an inner polytetrafluoroethylene tube and outer polyethylene of raised temperature resistance heating tube.

Findings

A seepage velocity calibration test was carried out using the improved monitoring system. The results showed that under a constant seepage velocity, the use of the dual-tube structure enables faster cooling, and the cooling rate accelerates with an increase in the diameter of the inner tube. The use of the dual-tube structure can improve the sensitivity of the seepage evaluation index ζv to the seepage velocity. When the inner diameter increases, ζv becomes more sensitive to the seepage velocity.

Originality/value

A mobile-distributed seepage monitoring method based on FBG sensing technology is proposed in which the FBG sensors are not fixed. Instead, the positions of the measurement points are changed to improve the spatial resolution. Meanwhile, the use of the dual-tube structure in the presented monitoring system can improve its sensitivity.

Details

Sensor Review, vol. 38 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 23 August 2021

Xiao Fang, Yajie Zeng, Feng Xiong, Jiang Chen and Fei Cheng

Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the…

Abstract

Purpose

Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed optical fiber sensing technology based on the temperature tracing method has been paid more attention due to its unique advantages of high sensitivity, good stability and high resolution. The purpose of this paper is to make a review of the existing related research, so as to facilitate the later scholars to understand and further study more systematically.

Design/methodology/approach

In this paper, three kinds of commonly used distributed fiber temperature measurement technologies are introduced. Based on the working principle, monitoring system, theoretical analysis, experimental research and engineering application of the fiber seepage monitoring technology, the present situation of dam seepage monitoring based on distributed fiber is reviewed in detail and their advantages and disadvantages are compared.

Findings

The thermal monitoring technology of seepage measurement depends on the accuracy of optical fiber temperature measurement (including the accuracy of the system and the rationality of the discrimination method), the correct installation of optical fiber and the quantitative analysis of temperature data. The accuracy of the current monitoring system can basically meet the existing measurement requirements, but the correct installation of optical fiber and the calibration of temperature data need to be further studied for different discrimination methods, and this field has great research value.

Originality/value

At present, there are many applications and research studies of optical fiber sensing in the field of structural health monitoring, and there are also reviews of related aspects. However, there is little or no review only in the field of seepage monitoring. This paper summarizes the research and application of optical fiber sensing in the field of seepage monitoring. The possibility of the gradient method to find its new prospect with the development of monitoring systems and the improvement of temperature resolution is discussed. The idea of extending the seepage monitoring method based on distributed optical fiber thermal monitoring technology to other monitoring fields is also given in the paper.

Details

Sensor Review, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 31 October 2018

Xiaozhi Ma, Albert P.C. Chan, Hengqin Wu, Feng Xiong and Na Dong

Although various concepts and techniques are introduced to the built environment to achieve a substantially efficient building production, the effective application of…

Abstract

Purpose

Although various concepts and techniques are introduced to the built environment to achieve a substantially efficient building production, the effective application of these methods in projects is of immense significance to the field of building construction. Among these initiatives, lean construction and building information modelling (BIM) are mainstream endeavours that share many common principles to improve the productivity of the built environment. This study aims to explore and explain how BIM-based integrated data management (IDM) facilitates the achievement of leanness in a built environment project.

Design/methodology/approach

This research is conducted through an ethnographic-action research that relies on the design-science approach and case study through a collaborative research project. As participants of the project, the researchers of this study cooperate with the practitioners to design the project approach and production workflows. Research data and evidence are obtained via participative observation, including direct observation, results of activities, unstructured meetings and self-analysis.

Findings

In this study, the project and production perspectives clarify the building design and production process, as well as analyse how BIM facilitates the achievement of leanness in building design and construction. BIM-based frameworks for IDM have been developed to handle miscellaneous information and data, as well as enhance multidisciplinary collaboration throughout the project life cycle. The role of the integrated BIM model as an information hub between the building design and building construction has been identified.

Research/limitations implications

The project and production views of building and construction are used in this study because the research purpose is to link the BIM-based IDM to lean construction. Although this mixed approach can slightly undermine the theoretical foundation of this study, a substantially comprehensive understanding can be gained as well.

Practical implications

This study provides a new perspective to understand how BIM-based IDM contributes to lean construction.

Originality/value

This study provides new insights into IDM in a built environment project with project and production views and presents BIM-based frameworks for IDM to achieve lean construction through the BIM process.

Details

Construction Innovation, vol. 18 no. 4
Type: Research Article
ISSN: 1471-4175

Keywords

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Article
Publication date: 7 July 2020

Yan-Chun Zhang, Wu-Zan Luo, Ming Shan, Dong-Wen Pan and Wen-Jie Mu

The aims of this study are to conduct a systematic review of public–private partnership (PPP) studies published from 2009 to 2019, to compare the results with Ke et al.

Abstract

Purpose

The aims of this study are to conduct a systematic review of public–private partnership (PPP) studies published from 2009 to 2019, to compare the results with Ke et al. (2009) who reviewed the PPP literature published from 1998 to 2008, and to trace the evolution of the PPP knowledge in the past two decades. This study also presents the possible directions that the PPP research may go towards in the future, arguably.

Design/methodology/approach

This study carried out a top journal-based search to identify the quality PPP articles published from 2009 to 2019. A total of 12 top-tier construction journals were systematically searched in the database of web of science (WOS), from which 279 PPP articles were identified for review.

Findings

The number of the identified articles, the titles of the journals, institutions, the most cited papers, and prevalent research methods were analyzed and compared. The existing PPP studies in construction journals were classified into seven streams. Through analysis of the PPP research status and gaps, five future research directions were revealed.

Originality/value

This study contributes to the current body of knowledge by revealing the research trend of PPP from 2009 to 2019. It presents the change of PPP development trend in the past decade through comparison with Ke et al. (2009). It also reveals the major research streams and points out the directions that the PPP research may go towards in the future. Moreover, this study is helpful to the practice as well. It can enhance the practitioners' understanding of the PPP development in the past decade. In addition, it identified the research institutions contributing the most in the area of PPP, which may serve as valuable reference for practitioners to locate the best institutions for consultancy or collaboration.

Details

Engineering, Construction and Architectural Management, vol. 27 no. 10
Type: Research Article
ISSN: 0969-9988

Keywords

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Article
Publication date: 28 June 2013

Gao Xian‐Zhong, Hou Zhong‐Xi, Guo Zheng, Zhu XiongFeng, Liu Jian‐Xia and Chen Xiao‐Qian

The purpose of this paper is to propose a methodology to determine the designing parameters for solar powered high‐altitude, long‐endurance (HALE) unmanned aerial vehicles (UAV).

Abstract

Purpose

The purpose of this paper is to propose a methodology to determine the designing parameters for solar powered high‐altitude, long‐endurance (HALE) unmanned aerial vehicles (UAV).

Design/methodology/approach

By depicting solar power distribution on earth, along with the efficiencies analysis of photo‐voltaic cells (P‐cell) and lithium‐sulfur battery (LS‐battery), the influence of energy to concept design parameters is analyzed first. Second, the lift efficiency is determined from ground to 20 km for HALE UAV. Third, the methodology to determine design parameters for HALE UAV is generalized by analyzing the carrying ability of some famous HALE UAVs, such as Zephyr, Helios, and so on.

Findings

Energy is the key constraint on design of HALE UAV. The questions about where HALE UAVs are capable of operating and how long they could work can be answered according to power density distribution on earth. The total mass of HALE UAV can be divided into two parts: one is the constant mass, the other is the mass increasing with area of wing. The total mass can be estimated by the former one; the later one plays an important role in estimating wing load in the designing process.

Practical implications

The only way to enhance carrying ability of HALE UAVs is to redistribute their wing load: lighter structure materials and a better method to fix P‐cell with lighter fundus are the key technologies to enhance HALE UAVs’ carrying ability. At current technological levels, it is not easy to design a UAV to achieve the aim of high‐altitude long‐endurance.

Originality/value

This paper presents a very efficient and convenient method to determine the designing parameters of HALE UAV.

Details

Aircraft Engineering and Aerospace Technology, vol. 85 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

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Article
Publication date: 15 October 2018

Xieling Chen, Shan Wang, Yong Tang and Tianyong Hao

The purpose of this paper is to explore the research status and development trend of the field of event detection in social media (ED in SM) through a bibliometric…

Abstract

Purpose

The purpose of this paper is to explore the research status and development trend of the field of event detection in social media (ED in SM) through a bibliometric analysis of academic publications.

Design/methodology/approach

First, publication distributions are analyzed including the trends of publications and citations, subject distribution, predominant journals, affiliations, authors, etc. Second, an indicator of collaboration degree is used to measure scientific connective relations from different perspectives. A network analysis method is then applied to reveal scientific collaboration relations. Furthermore, based on keyword co-occurrence analysis, major research themes and their evolutions throughout time span are discovered. Finally, a network analysis method is applied to visualize the analysis results.

Findings

The area of ED in SM has received increasing attention and interest in academia with Computer Science and Engineering as two major research subjects. The USA and China contribute the most to the area development. Affiliations and authors tend to collaborate more with those within the same country. Among the 14 identified research themes, newly emerged themes such as Pharmacovigilance event detection are discovered.

Originality/value

This study is the first to comprehensively illustrate the research status of ED in SM by conducting a bibliometric analysis. Up-to-date findings are reported, which can help relevant researchers understand the research trend, seek scientific collaborators and optimize research topic choices.

Details

Online Information Review, vol. 43 no. 1
Type: Research Article
ISSN: 1468-4527

Keywords

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Article
Publication date: 21 June 2019

Yuning Wang and Xiaohua Jin

Various factors may influence project finance when a multi-sourced debt financing strategy is used for financing capital investments, in general, and public infrastructure…

Abstract

Purpose

Various factors may influence project finance when a multi-sourced debt financing strategy is used for financing capital investments, in general, and public infrastructure investments, in particular. Traditional indicators lack comprehensive consideration of the influences of many internal and external factors, such as investment structure, financing mode and credit guarantee structure, which exist in the financing decision making of BOT projects. An effective approach is, thus, desired. The paper aims to discuss these issues.

Design/methodology/approach

This paper develops a financial model that uses an interval number to represent the uncertain factors and, subsequently, conducts a standardization of the interval number. Decision makers determine the weight of each objective through the analytic hierarchy process. Through the optimization procedure, project investors and sponsors are provided with a strategy regarding the optimal amount of debt to be raised and the insight on the risk level based on the net present value, as well as the probability of bankruptcy for each different period of debt service.

Findings

By using an example infrastructure project in China and based on the comprehensive evaluation, comparison and ranking of the capital structures of urban public infrastructure projects using the interval number method, the final ranking can help investors to choose the optimal capital structure for investment. The calculation using the interval number method shows that X2 is the optimal capital structure plan for the BOT project of the first stage of Tianjin Binhai Rail Transit Z4 line. Therefore, investors should give priority to selecting a capital contribution ratio of 45 per cent for this investment.

Research limitations/implications

In this paper, some parameters, such as depreciation life, construction period and concession period, are assumed to be deterministic parameters, although the interval number model has been introduced to analyze the uncertainty indicators, such as total investment and passenger flow, of BOT rail transport projects. Therefore, more of the above deterministic parameters can be taken as uncertainty parameters in future research so that calculation results fit actual projects more closely.

Originality/value

This model can be used to make the optimal investment decision for a project by determining the impact of uncertainty factors on the profitability of the project in its lifecycle during the project financial feasibility analysis. Project sponsors can determine the optimal capital structure of a project through an analysis of the irregular fluctuation of the unpredictable factors in project construction such as construction investment, operating cost and passenger flow. The model can also be used to examine the effects of different capital investment ratios on indicators so that appropriate measures can be taken to reduce risks and maximize profit.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 7
Type: Research Article
ISSN: 0969-9988

Keywords

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Article
Publication date: 13 November 2020

Zhen Hu, Qianmeng Li, Tingting Liu, Lu Wang and Zhe Cheng

Public private partnership (PPP) has gained increasing popularity around the globe. Whether the government needs to participate in the PPP special purpose vehicle (SPV) as…

Abstract

Purpose

Public private partnership (PPP) has gained increasing popularity around the globe. Whether the government needs to participate in the PPP special purpose vehicle (SPV) as an equity coinvestor is a critical issue in PPP development. This research aims to examine the influence of government equity investment on PPP performance by taking public-private communication as an intermediate variable.

Design/methodology/approach

A questionnaire survey was adopted as the main research method. PPP practitioners with extensive experiences from both the public and private sectors were targeted respondents. The survey results were subsequently analyzed using statistical data analysis method.

Findings

Based on the results from the questionnaire survey, this research indicates an inverted U-shaped relationship between the ratio of government equity and performance in PPP projects. In addition, communication plays a mediating role between government equity investment and PPP project performance.

Originality/value

This research explicates the relationship between the equity structure in a PPP SPV and the project performance. It provides important guidance and reference for PPP practitioners to structure the SPV and associated financial and commercial arrangements. It also offers valuable insights into the development of PPP policy, especially regarding the structuring of PPP models in China and elsewhere.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 26 August 2020

Rohit Gupta, Baidyanath Biswas, Indranil Biswas and Shib Sankar Sana

This paper aims to examine optimal decisions for information security investments for a firm in a fuzzy environment. Under both sequential and simultaneous attack…

Abstract

Purpose

This paper aims to examine optimal decisions for information security investments for a firm in a fuzzy environment. Under both sequential and simultaneous attack scenarios, optimal investment of firm, optimal efforts of attackers and their economic utilities are determined.

Design/methodology/approach

Throughout the analysis, a single firm and two attackers for a “firm as a leader” in a sequential game setting and “firm versus attackers” in a simultaneous game setting are considered. While the firm makes investments to secure its information assets, the attackers spend their efforts to launch breaches.

Findings

It is observed that the firm needs to invest more when it announces its security investment decisions ahead of attacks. In contrast, the firm can invest relatively less when all agents are unaware of each other’s choices in advance. Further, the study reveals that attackers need to exert higher effort when no agent enjoys the privilege of being a leader.

Research limitations/implications

In a novel approach, inherent system vulnerability of the firm, financial benefit of attackers from the breach and monetary loss suffered by the firm are considered, as fuzzy variables in the well-recognized Gordon – Loeb breach function, with the help of fuzzy expectation operator.

Practical implications

This study reports that the optimal breach effort exerted by each attacker is proportional to its obtained economic benefit for both sequential and simultaneous attack scenarios. A set of numerical experiments and sensitivity analyzes complement the analytical modeling.

Originality/value

In a novel approach, inherent system vulnerability of the firm, financial benefit of attackers from the breach and monetary loss suffered by the firm are considered, as fuzzy variables in the well-recognized Gordon – Loeb breach function, with the help of fuzzy expectation operator.

Details

Information & Computer Security, vol. 29 no. 1
Type: Research Article
ISSN: 2056-4961

Keywords

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Article
Publication date: 12 March 2019

Juan David Gonzalez-Ruiz, Alejandro Arboleda, Sergio Botero and Javier Rojo

The purpose of this paper is to develop an investment valuation model using the mezzanine debt mechanism based on blue bonds that explicitly allude to public–private…

Abstract

Purpose

The purpose of this paper is to develop an investment valuation model using the mezzanine debt mechanism based on blue bonds that explicitly allude to public–private partnerships (P3s) and project finance (PF). Additionally, this study proposes the financial captured value (FCV) theory for measuring how much financial value lenders may capture by becoming sponsors through financing of sustainable infrastructure systems (SIS).

Design/methodology/approach

The investment valuation model was validated through the Aguas Claras wastewater treatment plant as a case study.

Findings

The empirical results show that lenders may capture financial value by converting outstanding debt into equity shares throughout the operation and maintenance stage. Furthermore, case study results provide new insights into the implications of the debt–equity conversion ratio on the relationship between the sponsors’ internal rate of return and the FCV.

Research limitations/implications

The most significant limitation is the lack of primary and secondary information on blue bonds. Thus, robust statistical analyses to contrast results were not possible.

Practical implications

Researchers and practising professionals can improve their understanding of how mezzanine debt, P3s and PF into an investment valuation model allows financing SIS using a non-conventional financial mechanism. The recommendations will benefit both the academia as well infrastructure industry in bridging the gap between design theory and practice.

Originality/value

Sustainability components have not been addressed explicitly or combined in the financing’s structuring. Therefore, the investment valuation model could be considered a novel methodology for decision making related to financing and investment of SIS.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 5
Type: Research Article
ISSN: 0969-9988

Keywords

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