Search results

The purpose of this study is to propose an adaptive fault-tolerant control approach based on output feedback for a class of quadrotor unmanned aerial vehicles system. In the event of a controlled actuator failure, a stable flying of the aircraft can be achieved by selecting an appropriate sliding mode surface.

Aiming at the actuator failure of quadrotor aircraft during flight in the controllable range, a dynamic surface sliding mode passive fault-tolerant controller based on output feedback is designed based on the strong robustness of sliding mode method. Due to the unknown nonlinearity dynamics and parameter uncertainties in the system, a nonlinear observer is used to estimate them online.

The stability of the suggested algorithm is established using appropriate Lyapunov functions, and the performance of the proposed control approach is demonstrated using hardware-in-the-loop simulation.

An error performance function is introduced into the controller to ensure the convergence speed and accuracy of errors are within the predetermined range. By using the norm estimation method, there is only one parameter that needs to be updated in each step of the control process, which considerably minimizes the calculation burden. Finally, the validity of the proposed control scheme is verified on the hardware-in-the-loop simulation, and the results show that the proposed control method has achieved the desired results.

Leaders' behavior has a critical impact on workers' safety behavior. However, previous studies have shown contradictive views on the effect of different leadership styles on safety behavior. One reason may be that the effectiveness of leaders' behavior varies according to diverse contexts. This study examines the effect of transformational and transactional leadership (TsL) on the safety behavior of on-site workers under different levels of social capital in construction projects.

Safety behavior is divided into three types: safety compliance (SC), organizational-oriented safety participation and individual-oriented safety participation (ISP). Questionnaire survey data were collected from 302 construction workers in the Chinese construction industry.

The results indicate that the positive effect of transformational leadership (TfL) of frontline supervisors on the two types of construction workers' safety participation is enhanced when social capital is high, although TfL has no significant effect on SC behavior. In contrast, TsL can promote construction workers' SC behavior and organizational-oriented safety participation and social capital positively moderating these relationships. TsL has no significant effect on ISP, but its interaction with safety behavior is positively related to ISP.

This study explains the inconsistent findings of previous research related to the role of leadership in safety behavior by introducing the social capitaltheory and distinguishing safety participation into two typesThis study is confined to one specific country, future research may benefit from investigating whether the conclusions of this study will be different in other nations with diverse cultures.

The findings of the study provide frontline supervisors with new insights into improving workers' safety and the efficiency of leadership in safety management.

This study explains the inconsistent findings of previous research related to the role of leadership in safety behavior by introducing the social capital theory and distinguishing safety participation into two types.

The total essence of apparel manufacturing buildings (AMBs) is highly influenced by fire incidents which are caused direct or indirect impacts to the present building structure or even in old age. Hence, the purpose of this paper is to evaluate the fire risk of AMBs in Sri Lanka.

A literature review was conducted to explore the local and international fire incidents in AMBs and identify 24 factors that contribute to fire risk of AMBs. A questionnaire survey with professionals who have the knowledge and experience related to past fire incidents and 18 interviews with professionals of fire safety management were carried out. Content analysis was involved to evaluate interviewees’ opinions and relative importance index was involved to rank identified factors that contribute to the fire risk of AMBs.

The results revealed that due to the business nature of AMBs hold a high risk for fire incidents. The study discovered 83.4% of high fire risk prevailing in AMBs in Sri Lanka. Faulty wiring, welding work with electrical sparks and accumulation of waste fabric, paper and other garbage recognized as the top three factors that contribute to the fire risk of AMBs in Sri Lanka. Finally, the strategies proposed to eliminate identified all 41 factors that contribute to the fire risk of AMBs in Sri Lanka.

The paper helps to guide facility owners regarding the fire safety of AMBs in Sri Lanka.

The architecture, engineering and construction (AEC) industry encounter substantial risks and challenges in its evolution towards sustainable development. International businesses, multinational AEC organisations, technical professionals, project and portfolio management organisations face global connectivity challenges between business units, especially during the outbreak of novel coronavirus pandemic, to manage construction megaprojects (CMPs). That raises the need to manage global connectivity as a main strategic goal of global organisations. This paper aims to investigate barriers to integrating lean construction (LC) practices and integrated project delivery (IPD) on CMPs towards the global integrated delivery (GID) transformative initiatives and develop future of work (FOW) global initiatives in contemporary multinational AEC organisations.

A two-stage quantitative and qualitative research approach is adopted. The qualitative research methodology consists of a literature review to appraise barriers to integrating LeanIPD&GID on CMPs. Barriers are arranged into six-factor clusters (FCs), with a conceptualisation of LeanIPD&GID, GID strategy placements and FOW global initiatives with multiple validations. This analysis also involved semi-structured interviews and focus group techniques. Stage two consisted of an empirical questionnaire survey that shaped the foundation of analysis and findings of 230 respondents from 23 countries with extensive cosmopolitan experience in the construction of megaprojects. The survey examined a set of 28 barriers to integrating LeanIPD&GID on CMPs resulting from a detailed analysis of extant literature after validation. Descriptive and inferential statistical tests were exploited for data analysis, percentage scoring analysis, principal component analysis (PCA) and eigenvalues were used to elaborate on clustered factors.

The research conceptualised LeanIPD&GID principles and proposed GID strategy placements for LeanIPD&GID transformative initiatives and FOW global initiatives. It concluded that the most significant barriers to integration of LeanIPD&GID on CMPs are “lack of mandatory building information modelling (BIM) and LC industry standards and regulations by governments”, “lack of involvement and support of governments”, “high costs of BIM software licenses”, “resistance of industry to change from traditional working practices” and “high initial investment in staff training costs of BIM”. PCA revealed the most significant FCs are “education and knowledge-related barriers”, “project objectives-related barriers” and “attitude-related barriers”. Awareness of BIM in the Middle East and North Africa (MENA) region is higher than LC and LC awareness is higher than IPD knowledge. Whilst BIM adoption in the MENA region is higher than LC; the second is still taking its first steps, whilst IPD has little implementation. LeanBIM is slightly integrated, whilst LeanIPD integration is almost not present.

The research findings, conclusion and recommendation and proposed GID strategy placements for LeanIPD&GID transformative initiatives to integrating LeanIPD&GID on CMPs. This will allow project key stakeholders to place emphasis on tackling LeanIPD&GID barriers identified in this research and commence GID strategies. The study has provided effective practical strategies for enhancing the integration of LeanIPD&GID transformative initiatives on CMPs.

Integrated project delivery (IPD) has attracted considerable attention in recent years, however only a few review studies captured the dynamic and evolving nature of this topic. The purpose of this study is to review the most recent IPD publications, in order to shed light on future research.

Using a systematic review methodology, the study aims to synthesize the current IPD literature, and frame the latest research and development in this domain. A systematic review is conducted to identify the current state-of-the-art of IPD research and the latest research themes and trends in this domain. A bibliometric analysis is performed to explain characteristics of screened articles, and through a thematic analysis the latest themes and trends are recognized.

In this study, based on IPD characteristics (contractual-regulative, operational-cognitive and organizational-structural), research themes (legal, commercial, technological, procedural, cultural and structural), sub-themes and their associated trends are identified. The latest emerging trends are mostly related to the contractual characteristics of IPD, and are focused on the combination of IPD with new business models and developing contractual guidelines for promoting IPD applications in off-site and on-site construction projects.

This research contributes to the body of knowledge by synthesizing the state of the art of IPD in construction literature and exposing the latest research trends in this area. A theoretical framework of integration in an IPD context is developed, based on the literature. Finally, future areas of studies are discussed.

The purpose of this paper is to investigate critical success factors (CSFs) that enhance integration between building information modelling (BIM) and lean construction (LC) practices on construction mega-projects. BIM and LC have gained momentum in the past decade.

The Delphi survey technique was used to gauge opinions of a panel of 16 experts through a two-round Delphi questionnaire survey. Panel responses were scrutinised using inferential and descriptive statistical techniques.

In total, 30 CSFs were identified in the literature. The top ranked factor out of 30 that supports LeanBIM synergy was “collaboration in design, construction works and engineering management”. Other top rated CSFs were centric on people, data and technology elements. The research findings are important for project stakeholders, organisations, contractors, engineers and local authorities who implement LC and BIM synergies in construction mega-projects.

The research findings are important for project stakeholders, organisations, contractors, engineers and local authorities who implement LC and BIM synergies in construction mega-projects. The research recommends further hands-on training to increase the integration of BIM and LC practices in the architecture, engineering and construction industry and to enrich the extant body of knowledge in construction of mega-projects.

The purpose of this paper is to fit a logit model for dry bulkers transporting grains through the Panama Canal versus alternative routes destined to East Asia, originating on the US Gulf and East Coast. This is with the purpose of better understanding the attributes.

In this paper, grain transits both through the Panama Canal and alternative routes, which are examined, and a logit model is developed to explain the route decision from a carrier/vessel operator point of view.

Transit draft is the most important attribute in the route decision process for grains according to this study. Also, Panamax bulkers are the preferred vessel size into China, especially through the Cape of Good Hope route, impacting Panama Canal’s market share for grains.

This research used only a full year of grain traffic data approximating fiscal year 2018 (October 1, 2017 to September 30, 2018). Data will come mostly from the Panama Canal transit data and observations using IHS’s Market Intelligence Network (MINT).

This paper is highly dependent on visual observations of grains vessels through alternative routes using AIS data from MINT software.