Improving the accuracy of convolutional neural networks by ddentifying and removing outlier images in datasets using t-SNE

In the field of supervised machine learning, the quality of a classifier model is directly correlated with the quality of the data that is used to train the model. The presence of unwanted outliers in the data could significantly reduce the accuracy of a model or, even worse, result in a biased model leading to an inaccurate classification. Identifying the presence of outliers and eliminating them is, therefore, crucial for building good quality training datasets. Pre-processing procedures for dealing with missing and outlier data, commonly known as feature engineering, are standard practice in machine learning problems. They help to make better assumptions about the data and also prepare datasets in a way that best expose the underlying problem to the machine learning algorithms. In this work, we propose a multistage method for detecting and removing outliers in high-dimensional data. Our proposed method is based on utilising a technique called t-distributed stochastic neighbour embedding (t-SNE) to reduce high-dimensional map of features into a lower, two-dimensional, probability density distribution and then use a simple descriptive statistical method called interquartile range (IQR) to identifying any outlier values from the density distribution of the features. t-SNE is a machine learning algorithm and a nonlinear dimensionality reduction technique well-suited for embedding high-dimensional data for visualisation in a low-dimensional space of two or three dimensions. We applied this method on a dataset containing images for training a convolutional neural network model (ConvNet) for an image classification problem. The dataset contains four different classes of images: three classes contain defects in construction (mould, stain, and paint deterioration) and a no-defect class (normal). We used the transfer learning technique to modify a pre-trained VGG-16 model. We used this model as a feature extractor and as a benchmark to evaluate our method. We have shown that, when using this method, we can identify and remove the outlier images in the dataset. After removing the outlier images from the dataset and re-training the VGG-16 model, the results have also shown that the accuracy of the classification has significantly improved and the number of misclassified cases has also dropped. While many feature engineering techniques for handling missing and outlier data are common in predictive machine learning problems involving numerical or categorical data, there is little work on developing techniques for handling outliers in high-dimensional data which can be used to improve the quality of machine learning problems involving images such as ConvNet models for image classification and object detection problems

Knowledge creation: A case study of international construction joint venture projects in Thailand

In recent years, companies around the world are trying to expand internationally through collaborative agreements. ‘International Construction Joint Ventures’ (ICJVs) have become of significant interest as the global construction market continues to be integrated into a more competitive business environment. Moreover, ICJVs can be a mechanism for creating, transferring and improving knowledge and skills between partners. Knowledge creation has also been recognized as the successful mechanism of creating knowledge between local and foreign partners. Therefore, local partners who wished to enter into the emerging market needed to quickly develop the required resources. Thus, it is especially important to understand how new knowledge in ICJV projects can be transferred and adopted. Therefore, the purpose of this study is to investigate and characterise the knowledge creation process in ICJV projects and explore to what extent projects facilitate the process. A case study approach is adopted using three ICJV projects. As a result, this research provides the establishment of specific knowledge creation processes through an empirical investigation of ICJV projects in Thailand

Towards an intelligent ontology construction cost estimation system: Using BIM and new rules of measurement techniques

Construction cost estimation is one of the most important aspects of construction project design. For generations, the process of cost estimating has been manual, time-consuming and error-prone. This has partly led to most cost estimates to be unclear and riddled with inaccuracies that at times lead to over- or underestimation of construction cost. The development of standard set of measurement rules that are understandable by all those involved in a construction project, have not totally solved the challenges. Emerging Building Information Modelling (BIM) technologies can exploit standard measurement methods to automate cost estimation process and improve accuracies. This requires standard measurement methods to be structured in ontological and machine readable format; so that BIM software packages can easily read them. Most standard measurement methods are still text-based in textbooks and require manual editing into tables or Spreadsheet during cost estimation. The aim of this study is to explore the development of an ontology based on New Rules of Measurement (NRM) commonly used in the UK for cost estimation. The methodology adopted is Methontology, one of the most widely used ontology engineering methodologies. The challenges in this exploratory study are also reported and recommendations for future studies proposed

Reality capture of buildings using 3D laser scanners

The urgent need to improve performance in the construction industry has led to the adoption of many innovative technologies. 3D laser scanners are amongst the leading technologies being used to capture and process assets or construction project data for use in various applications. Due to its nascent nature, many questions are still unanswered about 3D laser scanning, which in turn contribute to the slow adaptation of the technology. Some of these include the role of 3D laser scanners in capturing and processing raw construction project data. How accurate are the 3D laser scanner or point cloud data? How does laser scanning fit with other wider emerging technologies such as building information modeling (BIM)? This study adopts a proof-of-concept approach, which in addition to answering the aforementioned questions, illustrates the application of the technology in practice. The study finds that the quality of the data, commonly referred to as point cloud data, is still a major issue as it depends on the distance between the target object and 3D laser scanner’s station. Additionally, the quality of the data is still very dependent on data file sizes and the computational power of the processing machine. Lastly, the connection between laser scanning and BIM approaches is still weak as what can be done with a point cloud data model in a BIM environment is still very limited. The aforementioned findings reinforce existing views on the use of 3D laser scanners in capturing and processing construction project data

Prediction of multi-inputs bubble column reactor using a novel hybrid model of computational fluid dynamics and machine learning

The combination of machine learning and numerical methods has recently become popular in the prediction of macroscopic and microscopic hydrodynamics parameters of bubble column reactors. Such numerical combination can develop a smart multiphase bubble column reactor with the ability of low-cost computational time when considering the big data. However, the accuracy of such models should be improved by optimizing the data parameters. This paper uses an adaptivenetwork-based fuzzy inference system (ANFIS) to train four big data inputs with a novel integration of computational fluid dynamics (CFD) model of gas. The results show that the increasing number of input variables improves the intelligence of the ANFIS method up to R = 0.99, and the number of rules during the learning process has a significant effect on the accuracy of this type of modeling. Furthermore, the proper selection of model’s parameters results in higher accuracy in the prediction of the flow characteristics in the column structure

Prediction of compression index of fine-grained soils using a gene expression programming model

In construction projects, estimation of the settlement of fine-grained soils is of critical importance, and yet is a challenging task. The coefficient of consolidation for the compression index (Cc) is a key parameter in modeling the settlement of fine-grained soil layers. However, the estimation of this parameter is costly, time-consuming, and requires skilled technicians. To overcome these drawbacks, we aimed to predict Cc through other soil parameters, i.e., the liquid limit (LL), plastic limit (PL), and initial void ratio (e0). Using these parameters is more convenient and requires substantially less time and cost compared to the conventional tests to estimate Cc. This study presents a novel prediction model for the Cc of fine-grained soils using gene expression programming (GEP). A database consisting of 108 different data points was used to develop the model. A closed-form equation solution was derived to estimate Cc based on LL, PL, and e0. The performance of the developed GEP-based model was evaluated through the coefficient of determination (R2), the root mean squared error (RMSE), and the mean average error (MAE). The proposed model performed better in terms of R2, RMSE, and MAE compared to the other models

User-centred design for collaborative 4D modelling

Purpose - The purpose of this paper is to clarify the CSCW in collaborative 4D modelling and its user interface (UI)/interaction designs for prototyping. Four-dimensional (4D) modelling technology has potentials to integrate geographically dispersed planners to achieve collaborative construction planning. However, applying this technology in teamwork remains a challenge in computer-supported collaborative work (CSCW).Design/methodology/approach - The research adopted user-centred design (UCD) methodology to investigate a usable 4D collaboration prototype through analysis, design and usability testing. By applying CSCW theories, it first clarified the meaning of 4D CSCW to formulate design propositions as design target. By leveraging UCD theories, subsequently, the first-stage research sought an optimal standalone 4D modelling prototype following a parallel design approach. At the second stage, it further investigated into a collaborative 4D modelling prototype using an iterative design. It adopted collaborative task analysis into the UI/interaction design extension for a collaborative prototype based on results obtained from the first stage. The final usability testing was performed on the collaborative prototype to evaluate the designed CSCW and UI in a controlled geographically dispersed teamwork situation.Findings - The test results and user feedback verified their usability. It also disclosed design weaknesses in collaborators' awareness and smooth tasks' transitions for further enhancement.Originality/value - The combination of CSCW and UCD theories is practical for designing collaborative 4D modelling. It can also benefit designs for collaborative modelling in other dimensions like cost analysis, sustainable design, facility management, etc. in building information modelling.Published versio

Integrated microcomputer applications in formwork design

Despite the arguments in favour of the application of computers in temporary works design, as highlighted in previous research, there was a lack of suitable software at the start of this research. The main objective of this research has been to design and develop software for a major temporary works item. Formwork design was selected from several classes as it provided a larger problem domain. Achieving the main objective necessitated the establishment of a strategy for implementing software in temporary works design using a systems engineering approach. After studying the state-of-the-art of computer application in engineering, construction, and temporary works design, an integrated program network strategy was established for implementing software in temporary works design. This involved the coupling of microcomputer-based packaged Computer-Aided Drafting and Database Management Systems with temporary works design applications. The coupling was achieved through the combination of a database/executive approach. This strategy was then used to design, develop, and validate a computer-aided design system for formwork. To establish the formwork design process, contemporary formwork design methods were studied by reviewing literature and holding informal discussions with eight practicing formwork designers. This study, coupled with an analysis of the formwork designer's. tasks, enabled a functional specification to be produced for a computer-aided design system for formwork. This was used to establish six individual modules that make up the system as follows: a formwork database management module; a concrete pressure modelling module; a rational formwork design module; a detailed form work design module; a drafting module; and a schedule of quantities and cost quotation module. A windowing and menu based human-computer interface was designed and developed for the applications to be developed. The system was produced by designing, developing and testing individual modules, which were finally integrated to form a comprehensive Formwork Integrated Computer-Aided Design System (FICADS). The functions integrated include the analysis/design, drafting, scheduling of quantities, and cost estimating of formwork. The system was tested and assessed by means of several case studies and demonstrations to expert form work designers which proved favourable. The main achievement has been the development of a computer-aided design system for formwork that was acceptable to formwork designers. In the development of the system, a conceptual framework within which temporary works design systems can be developed with great flexibility, confidence and a minimum of programming effort has been established

Interactive computer-aided formwork design

While disciplines such as structural analysis are reaping the benefits of computer implementation, temporary works design lags well behind. Some of the reasons given by temporary works designers are that their designs are very practical and depend largely on the designer's experience and engineering judgement. By designing a highly interactive user friendly interface, a comprehensive program that runs on IBM compatibles has been developed. The program can be used to design formwork for walls and soffits using traditional timber and/or proprietary formwork components. The program incorporates many features commonly associated with business oriented software interfaces, placing special emphasis on the ease of use and at the same time allowing users to incorporate their own engineering judgement. The user interface features include the use of bar menus, windows and data entry screens. Formwork design may involve the use of material components from different sources, therefore, it is highly data dependent. Consequently, a Database Management System (DBMS) is used to manage a database of material properties, costs and other attribute data. Formwork members are designed using a rational approach to BS 5975: 1982 and the recommendations of the Concrete Society's text "Formwork: a guide to good practice". The program produces design details, a schedule of quantities, a cost comparison between purchased and hired proprietary formwork and a cost estimate

Computer-based modeling of concrete pressures on complex shaped wall formwork

The determination of concrete pressures on formwork is an important aspect of temporary works design. CIRIA provides a data sheet for easy abstraction of maximum concrete pressure values for formwork design. The data sheet cannot be used directly where complex shaped walls are encountered. A data model has been developed to describe the geometry of wall cross-sections so that the concrete pressure envelopes on complex shaped wall formwork can be computed systematically. The procedure described in CIRIA Report 108 for computing maximum pressures on non-parallel sided walls is used to implement the data model in a computer program developed to interface with a computer-aided drafting package. This allows the use of CAD techniques for describing the model geometry and associated attribute information to the computer, thereby providing a good user interface. An example is used to illustrate the application of the model to a complex shaped wall