• General Article

    Accelerating multi-class defect detection of building façades using knowledge distillation of DCNN-based model
    Kisu Lee, Sanghyo Lee and Hayoung Kim
    This paper proposes a high-speed detection method for multi-class defects in residential building façades. Automated deep learning-based defect detection systems have been ... + READ MORE
    This paper proposes a high-speed detection method for multi-class defects in residential building façades. Automated deep learning-based defect detection systems have been developed to compensate for various problems in existing human-oriented defect management methods for building façades. However, the superior performance of deep learning-based models occasionally causes a trade-off with the inference time. In other words, using a lightweight model results in performance degradation, which we propose to prevent through a knowledge distillation (KD) method. This study was conducted using approximately 10,000 building façade images, which were obtained using drones. Using these data, we compared the performances of the lightweight model trained simply and the model trained with a KD method. As a result, mean average precision (mAP) increased by approximately 20% and inference time decreased by approximately 2.5x. - COLLAPSE
    June 2021
  • General Article

    Automated defect classification in the maintenance phase using a channel attention-based convolutional neural network model of natural language processing
    Donguk Yang, Byeol Kim and Hayoung Kim
    Defect management of buildings is considered an important field of research, not only for maintaining the performance of buildings and extending their ... + READ MORE
    Defect management of buildings is considered an important field of research, not only for maintaining the performance of buildings and extending their lifespan, but also for preventing additional costs. However, because of the recent increase in the number of apartments resulting from urbanization, the scope of management over which that limited management personnel have to take charge has broadened, making it difficult to manage defects efficiently. The systematic classification of defect cases that must precede addressing this is an important concern among construction researchers and managers. Such a classification allows managers to analyze the trend of defects to respond quickly to them and formulate strategies to prevent the occurrence of the same defects. Therefore, we propose a model that automatically classifies defect text data by applying deep learning to overcome the limitations that manage defect cases through simple computerization. This model is designed based on Convolutional Neural Network (CNN) defines defect text data as input and generates classification each of four tasks as output. In terms of model development, we not only design a CNN-based model, but also improve the model’s performance by using a channel attention mechanism. The complete development of this model can contribute to establishing an efficient building defect management system in a Korean building environment and to facilitating defect management work by providing objectivity and consistency to managers. - COLLAPSE
    June 2021
  • General Article

    Review of BIM for existing building sustainability performance and green retrofit
    Yaik-Wah Lim, Philip C.H. Ling, Mohd Hamdan Ahmad, Pau Chung Leng, Azari Mat Yasir, Wai Lai Chan and Noraslinda Abdul Rahman
    Green retrofit is considered an effective strategy to improve the sustainability of existing buildings which have high energy usage and carbon emission ... + READ MORE
    Green retrofit is considered an effective strategy to improve the sustainability of existing buildings which have high energy usage and carbon emission especially at urban area due to scarcity of land. Nevertheless, the conventional method of analyzing and green retrofitting the existing buildings depends on various disjointed processes and decision-makings. Though the development of Building Information Modeling (BIM) offers integrated solutions for green retrofit by evaluating different building sustainability performances based on a centralized digital model, the actual applications of such technology still require further studies. Thereby this paper reviews the previous research related to the use of BIM and relevant computational technologies such as simulation and visual programming for green retrofit of existing buildings. The review shows that the recent research on this area covers case studies, framework developments and reviews. Based on the findings, common BIM sustainability tools, performance parameters and design parameters in the recent research on existing buildings were identified. Furthermore, the issues and challenges faced in the implementation of BIM for green retrofit were raised including missing information, data transfer issue, lack of unified platform as well as the low automation of BIM and building performance tools. Through the review, this paper provides important guidance to the researchers and practitioners to implement BIM for green retrofitting of existing buildings. - COLLAPSE
    June 2021
  • General Article

    Agenda for first costs reduction in sustainable buildings for emerging markets
    Samuel Ekung, Isaac Odesola and Adeniran Lashinde
    The development of Sustainable Buildings (SB) is laden with high first costs that inhibit their adoption diffusion. The strategies to reduce the ... + READ MORE
    The development of Sustainable Buildings (SB) is laden with high first costs that inhibit their adoption diffusion. The strategies to reduce the first cost and the framework of enabling policies for inspiring dispersed adoption remain tactless and fundamentally unstructured amongst the growing research engagements. This study developed and validated Costs Innovation and Improvement Framework for Sustainable Building Implementation (CIIFSUB) using mixed data analysed using conversational analysis, descriptive and inferential statistics. The integrative framework combines synergy between stakeholders’ roles and innovative practices to demonstrate focal areas for improving cost drivers toward cost reduction (CR) in specific SB development stages. Affordable SB is therefore possible based on the hypothesised interaction between established CR strategies and cost drivers. The performance of CIIFSUB varies among experts (88.711, p (0.000 < 0.05), with significant inter-rater agreement (W, 0.672), the prospect of the framework to achieve major CR is high. Achievable CR using this strategic agenda involves two-phase implementation, pre-project and project actions. Pre-project activities would improve stakeholders’ readiness towards project uptake, while project activities direct systematic interventions towards affordability during planning, design, procurement and construction. The agenda provides adopters in emerging markets with the implementation compass to achieving radical CR benefits in SB development. - COLLAPSE
    June 2021
  • General Article

    A tool to evaluate what makes a factory sustainable
    Lia Marchi and Ernesto Antonini
    Industrial sites significantly affect the quality of people’s living environment. Research and practice show increasing attention for the environmental issues at ... + READ MORE
    Industrial sites significantly affect the quality of people’s living environment. Research and practice show increasing attention for the environmental issues at process scale, minor for the social ones at site level; while to get more sustainable factories these aspects must be approached holistically. As part of a larger research on factory landscape compatibility, this study aims to provide companies with a tool to understand what helps make their factory compatible with the surroundings, thus which impacts should be mitigated. To that end, a preliminary detection of a factory’s interferences with the context is required; but current assessment tools lack an integrated approach, while addressing many specific issues. To fill the gap, the study provides: (i) a critical review of existing assessment tools and the reason why the LEED protocol was chosen as reference; (ii) a proposal for its improvement by an additional category of indicators, based on 8 new credits which address perceptual-aesthetic aspects; (iii) the worksheets’ outline of new credits. Moreover the paper summarizes two further research outputs: a Catalogue of good practices for the mitigation of impacts and the tool application on the Italian case study of Orogel facilities. The discussion about limitations and opportunities of the developed tool completes the paper. - COLLAPSE
    June 2021
  • General Article

    How to measure the green façades environmental effectiveness? a proposal to green façade systems technical guide
    Marwa Hisham El-Zoklah and Tamer Refaat
    Residential buildings in Egypt consume about 40% of total energy consumption according to the 2018-2019 energy consumption report the residential buildings. Most ... + READ MORE
    Residential buildings in Egypt consume about 40% of total energy consumption according to the 2018-2019 energy consumption report the residential buildings. Most of this energy consumes in H-VAC to achieve the thermal comfort. So that, the architects start to use the Green façade systems (GFS) to minimizing the heat gain which came from the building envelope to optimize the energy efficiency and also to reduce climatic stress (radiation, heat gain, temperature …etc.), air pollution, CO2 emissions, sound reflections & external noise with taking into consideration the operational costs to gain a market edge and to achieve the best result of GFS Installation the technical guide is very important to insure its success in all of its installation stages and insure the reduction of building energy consumption cost. Also to define the effect of GFS installation on energy efficiency a DesignBuilder has been used to simulate its effectiveness in both (directly to the wall installation and with 60cm air gap) on a residential unit with 12cm wall thickness in 6th October city, Egypt. It installed at east and west direction. The results shows that installation on 25cm wall gives better saving ratio than 12cm also, shows that in west direction: It saved energy by 19:23.7%, decreased CO2 emission by 12.6:18%, heating loads by 18.8:22%, cooling loads by 19: 24.6% and electricity bill payment by 35:38.7%. And in east direction: it saved energy by 17.5:19.7%, decreased CO2 emission by 11.3:16.8%, heating loads by16.8:18.8%, cooling loads by 17.6:22.7% and payment by 29:31.8%. - COLLAPSE
    June 2021
  • General Article

    Demand forecasting of micro mobility using a gated recurrent unit
    Hyunji Park and Seungjune Hwang
    Mobility as a service (MaaS) aims to integrate moving, which has been segmented by the combination of various means of transportation, and ... + READ MORE
    Mobility as a service (MaaS) aims to integrate moving, which has been segmented by the combination of various means of transportation, and payment systems as a service and provide door-to-door services to users. Providing complete door-to-door MaaS services to users requires advances in the level of transportation services to solve the first-last mile problem. Micro mobility, such as public bikes and electric scooters, is drawing attention as a means of transportation that can be used for first-last mile travels. Providing complete door-to-door services to MaaS users requires preemptive responses to the demand for micro mobility as well as the ability to track that demand in real time. This essentially requires the ability to forecast the demand for micro mobility. Unlike existing public transportation, micro mobility does not have a fixed travel route or travel time, which causes large variations in demand within short time frames. Therefore, demand forecasting methods different from those used for existing public transportation are needed. In this study, a hybrid forecasting model was designed to forecast the demand for micro mobility that fluctuates sharply and is irregular, and its accuracy was verified. The hybrid forecasting model was based on a genetic algorithm and deep learning algorithm, and the Seoul public bike service, Ttareungyi, was selected as a representative example of micro mobility. To test the model, the rental and return data for Ttareungyi were predicted at the station with the highest eigenvector centrality. The results show higher forecasting accuracy with the hybrid forecasting model than with single forecasting models. The rental and return data forecast by the hybrid forecasting model could be provided as 'expected rental availability' through a MaaS application, and operators could use the data to efficiently relocate bikes to meet demand. - COLLAPSE
    June 2021
  • General Article

    A novel methodology to monitor passenger mobility performance in urban subway stations
    Young Jo, Eunbi Jeong, Seolyoung Lee and Cheol Oh
    Sustainable smart technology is important to prevent roaming passengers and improve pedestrian space environment by providing effective route information service in subway ... + READ MORE
    Sustainable smart technology is important to prevent roaming passengers and improve pedestrian space environment by providing effective route information service in subway stations. A pedestrian trajectory collection system based on LiDAR sensors can continuously track individual passengers with a wide detection range and high accuracy for monitoring pedestrian space in a subway station. This study developed a methodology for detecting and classifying abnormal passenger trajectory patterns in a subway station using passenger trajectory data collected from LiDAR sensors. Further, feature vectors were extracted toward the reliable characterization of passenger walking trajectories. An ensemble method that combines decision tree, support vector machine, and artificial neural network was adopted to increase the classification accuracy for abnormal passenger trajectory patterns. The proposed ensemble method was able to obtain 94.4% classification accuracy, which was superior to that of a single classifier. In addition, this study devised a performance measure to identify the performance of passenger mobility in subway stations, referred to as passenger mobility index (PMI), based on the classification results. The proposed methodology is expected to be utilized to provide a passenger mobility evaluation system based on intelligent facilities such as smart construction and safety. - COLLAPSE
    June 2021
  • General Article

    Analysis of embodied carbon emissions for a relocatable modular steel building in South Korea
    Hanbyeol Jang, Hyeongjae Jang, Seungjun Roh and Yonghan Ahn
    As the construction industry is emerging as a major factor in global environmental problems, research is ongoing to reduce the environmental impact ... + READ MORE
    As the construction industry is emerging as a major factor in global environmental problems, research is ongoing to reduce the environmental impact in the construction process. In order to reduce the environmental impact of the construction process, the application of the modular construction method that can minimize the procedure in construction stage is expanding. Various studies have been conducted to expand the application of modular buildings, and environmental benefits analysis is also under way. However, the research conducted so far has targeted modular timber buildings that applied the structure of early modular buildings. The environmental impact evaluation studies of modular steel buildings, which are mainly used for the advantages of various aspects such as structure, are insufficient. The purpose of this study is to prove the sustainability of the modular steel building by conducting an analysis of the embodied carbon emissions. As a result of the analysis, it was possible to reduce the embodied carbon emission by about 37.75% of the modular steel building compared to the conventional construction method. Through these results, it was demonstrated that the environmental benefits of modular steel buildings reduce carbon emissions quantitatively in the same context as the environmental benefits of modular timber buildings already found in previous studies. These results are expected to be used as a basis to support the overall sustainability of the modular construction method. - COLLAPSE
    June 2021
  • General Article

    Evaluation of flexural performance of composite beams composed of steel and timber
    Keumsung Park and Myongkeun Kwak
    Cross-sectional strength can be improved with maximized ductility by using a combination of excellent steel and structural glued laminated timber (GLT). In ... + READ MORE
    Cross-sectional strength can be improved with maximized ductility by using a combination of excellent steel and structural glued laminated timber (GLT). In this study, a composite cross-sectional shape in which structural steel bent in the form of two C-channels was inserted into GLT was developed. The three specimens were tested for their flexural performance: a GLT specimen consisting only of pure wood for examining the effect of steel insertion as well as a screw-connected specimen and a specimen using polyurethane adhesive for examining the adhesion of steel according to the connection method. As a result of testing the flexural performance, the composite section connected by self-drilling screws demonstrated the adhesive strength for the steel material to reach the yield stress, but it failed to achieve a fully composite behavior. The polyurethane-adhered composite beam demonstrated fully composite behavior until reaching the maximum load. The flexural strength and stiffness of the polyurethane-adhered composite beam were 1.52 and 1.97 times higher, respectively, than those of the GLT beam, demonstrating an excellent improvement in the strength and stiffness compared with the cross-sectional area. - COLLAPSE
    June 2021
Journal Informaiton International Journal of Sustainable Building Technology and Urban Development International Journal of Sustainable Building Technology and Urban Development
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