Class Files Research Articles

Enhancing Open BIM Interoperability: Automated Generation of a Structural Model from an Architectural Model

Building information modelling (BIM) is an appreciated technology in the field of architecture and construction management. Collaboration of information in BIM has not been fully utilized in the structural engineering stream as many engineers keep on working with previous prevailing design approaches. Failure to adequately facilitate automation in design could lead to structural defects, construction rework, or even structural clashes, with major financial implications. Given the inherent complexity of large-scale construction projects, the ‘manual design and detailing’ of structure is a challenging task and prone to human errors. Against this backdrop, this study developed a 4D building information management approach to facilitate automated structural models for professionals designing all the elements required in reinforced concrete (RC) structures like slabs, beams, and columns. The main contribution of this study is to obtain structural models directly from architecture models automatically, which reduces effort and possible errors in the previous prevailing approaches. The framework enables execution of all the model design works automatically through coding. This is achieved by executing a script which is beneficial for integrated project delivery (IPD). The 3D structural model in BIM software presented in this study extracts and transfers the geometrical data and links these data in Industry Foundation Classes (IFC) files using integration facilitated by Python 3.6 and IFCopenshell. The developed automated programme framework offers a cost-effective and accurate methodology to address the limitations and inefficiencies of traditional methods of structural modelling, which had been carried out manually. The authors have developed a novel tool to extract structural models from architectural models without proprietary software, greatly benefiting BIM managers by enhancing 3D BIM models. This advancement toward Open BIM, crucial for the architecture, engineering, and construction (AEC) industry’s future, is accessible to educators and beginners and highlights BIM’s effectiveness in improving structural analysis and productivity. The core finding of this study is to generate a structural model from an architecture model by automating the script with Python integration of IFC and IFCopenshell. The merits of the developed framework are reduced clashes, more economical structural modelling, and fully automated smart work as functions of the IPD.

Industry Foundation Class-Based Building Information Modeling Lightweight Visualization Method for Steel Structures

The efficient extraction, storage, and visualization of geometric and semantic information is a key foundation for the operation of the building information modeling (BIM) platform. This study aims to develop a lightweight BIM system and optimize the system’s performance according to the specific characteristics of steel structures. This study proposes several novel techniques for extracting and decoupling the geometric and semantic information of components from industry foundation class (IFC) files. A redundancy removal approach combining the principal content analysis (PCA) algorithm and the Hausdorff-based comparison algorithm is proposed to identify standardized steel components, and a lightweight visualization method on Web3D for redundant instances is also presented. A loading mechanism of the level of detail (LOD) model based on a mesh simplification algorithm is presented to optimize the display efficiency. The developed system is evaluated by three steel structural models. Using the redundancy removal approach, the number of instances is decreased by 96.46% in less than 30 s and over 30 FPS (frame per second) is kept when rendering. Using the LOD loading mechanism, 95.38% of vertices and 98.46% of patches are eliminated under 50 mm precision. The experiment results indicate that users can quickly load large BIM models and fetch sufficient information from the website.

An empirical study of code reuse between GitHub and stack overflow during software development

With the rise of programming Q&A websites (e.g., Stack Overflow) and the open-source movement, code reuse has become a common phenomenon. Our study aims to provide a comprehensive study of the code reuse behavior of programmers during software development, i.e., we mainly focus on the code reuse between the code snippets in the commits of open-source projects and the code snippets on Stack Overflow (SO). The open-source java project code dataset we construct contains 793 projects which include 342,148 modified code snippets, and the SO code dataset includes 1,355,617 posts. Then, we employ a code clone detection tool to identify the instances of code reuse between the modified code snippets of commits and the code snippets of the SO posts. We find that the average code reuse ratio of the projects is 6.32%, which will have a significant upward trend in the future. Additionally, we find that experienced developers seem to be more likely to reuse the code on SO, and prefer to reuse posts with more favorites and higher scores. We combine deep learning and topic analysis algorithms to fully exploit the semantic information of SO posts. The result shows a certain difference in the distribution of post types reused by bug-related commits and non-bug-related commits. We also discover that the code reuse ratio (14.44%) in java class files that have undergone multiple modifications is more than double the overall code reuse ratio (6.32%). Finally, we discuss the reuse habits of programmers and find that they may refer to multiple posts in one reuse, and these posts are related to a certain extent. From these results, our study provides multiple practical insights for different stakeholders: researchers, developers, and the SO platform.

Research on Partial Model Extraction of Railway Infrastructure Based on the Industry Foundation Classes Files

Research on Partial Model Extraction of Railway Infrastructure Based on the Industry Foundation Classes Files

LOD2 for energy simulation (LOD2ES) for CityGML: A novel level of details model for IFC-based building features extraction and energy simulation

As a widely accepted urban geographical analysis data format, CityGML proposed different levels of details (LOD) for buildings, and LOD2 is the most recognized level for various energy analyses. However, building energy simulation requires detailed information on the geometry and thermal properties, LOD2 is not sufficient for large-scale simulation of urban buildings. This study proposed a novel LOD2 for energy simulation (LOD2ES) that extends LOD2 with additional information on façade, glazing, internal geometry, and roof details. LOD2ES can extract relevant abstracts from standard Industry Foundation Classes files and construct efficient energy simulation and assessment models. To validate the proposed LOD2ES data scheme, this study conducted a case study on 10 typical buildings and compared LOD2ES with other mature data schemes, including LOD2, LOD2.5, and LOD2plus, in three different climate regions. The results show that with improved building information, the simulation results have a significant variation (20%–22%) from conventional LOD2 models. It has a better performance than LOD2plus and the running time is about 15% less.

Leveraging railway topology to automatically generate track geometric information models from airborne LiDAR data

Geometric information modelling from point cloud data (PCD) is a fundamental step of the digital twinning process for rail infrastructure. Currently, this onerous procedure outweighs the anticipated benefits of the resulting model and expends 74% of the modellers' effort on converting PCD to a model. The cost of the resulting geometric information models (GIM) can be reduced by automating the modelling process. State-of-the-art methods cannot offer large-scale GIM generation required over kilometres without forfeiting precision and manual cost. This paper addresses the challenge of achieving such automation by leveraging the highly standardised topology of railways to automatically generate GIMs of rail track structures.The method first automatically segments rails and track beds, delivering labelled point clusters of track structure elements. Next, it converges the segmented rails with pre-defined parametric assemblies of different rail profiles and uses a mesh-based approach to reconstruct the geometry of the track bed, delivering industry foundation classes (IFC) files of railway track structure elements. Experiments on 18.5 km railway PCDs yielded an average segmentation of 98.1% and 94.9% F1 scores and overall modelling accuracy of 3.5 cm and 2.8 cm root mean square error (RMSE)s for rails and track beds. The proposed method can realise an estimated time savings of 88.9% without needing any manual inputs.

OpenBIM-based assessment for social cost of carbon through building life cycle

Buildings produce many carbon emissions in their life cycle, which leads to global warming, human disease, ecosystem destruction, and food shortages. These harms are translated and revealed into the social cost of carbon (SCC), but assessing the building SCC considering protection objects is still difficult due to the lack of adequate and rapid tools. Therefore, this paper proposes a method based on OpenBIM to calculate the SCC through the building life cycle. This method reflects the cause-effect chains of carbon emissions on human health, ecosystem quality, and social assets under LIME, EPS, and ReCiPe approaches. An original tool, NMBIM, is developed based on this proposed method, which calculates the SCC of a case building by directly importing industry foundation classes (IFC) files. The case results show that the maximum life cycle SCC reaches 5872.4 RMB/m2, which exceeds the construction cost. Although SCC results obtained by different LCIA models vary widely, the ones of human health are the most concerned protection objects. This paper provides an effective method for standardly storing and optimizing SCC at the project design stage, which contributes to construction industry planning, construction company decision-making, and public regulation.

Evolusi Sistem Operasi Android: Sebuah Tinjauan Literatur

In the past, mobile phones were only used to make calls, but with the introduction of smartphones, mobile phones have evolved into low-power handheld processing systems. This evolution is due to the operating system for mobile phones that make them sophisticated and have their own processing and storage. Today mobile phones provide many functions from making calls to sending messages, multimedia sharing, email, socializing applications, word processing, excel worksheets to various multiplayer games and much more. The operating systems for these handheld devices are iOS from Apple Inc, Windows from Windows Inc and Android from Google. Among competitors in the smartphone operating system industry, Android holds the largest market share in terms of units shipped worldwide and number of users. Android is an open source operating system based on the linux kernel where applications run on an application framework that controls activities supported by Dalvik libraries and virtual machines that compile and convert all java class files into a single file. There are several virtual machines running simultaneously on a single device that run different applications or application instances. The Android operating system provides memory management, process management to run applications and services. Every android release improves the user experience and brings enhanced features. This paper presents a study of the evolution that each release brings to the android operating system.

Comparison of University Students’ Perceptions of Interaction in English Classes on Two Online Platforms: Gather.town vs. Zoom

This study is purported to compare university students’ perceptions of interaction in English classes on two synchronous online platforms: Gather.town, the metaverse vs. Zoom, non-metaverse. Moore’s three types of interaction in online education are utilized: learner-learner, learner-teacher, and learner-content. A total of 22 college students at an English pedagogy class participate in the survey; later, four individual students are interviewed. Non-parametric repeated-measures analysis utilized to see differences between the two platforms reveals the following findings. Firstly, students’ interaction on the metaverse between learners and learners and between learners and the teacher is significantly greater than its counterpart, not for learner-to-content interaction. Secondly, avatar use on the map-based classroom on the metaverse provides students with both multiple ways for interaction and an optimized environment for small group activity. In contrast, student-initiated interaction on Zoom is limited. Thirdly, the metaverse platform has easy ways of communication with the teacher. Finally, for learner-to-content interaction, difficulty in accessing and sharing class files on the metaverse causes inconveniences. Pedagogical implications are discussed for language teachers aspiring to adopt the metaverse for their future classes.

IFC-based embodied carbon benchmarking for early design analysis

Current legislation focuses on reducing the operational carbon impact of buildings. However, the production of materials used in construction generates a considerable amount of carbon, known as embodied carbon, that accounts for a sizeable fraction of the environmental impact of a building during its lifecycle. We present a newly developed tool, pycab, which calculates the embodied carbon of a building directly at the design stage and compares it to the Royal Institute of British Architects (RIBA) 2030 Climate Challenge Target Benchmarks. As input, the tool uses standard Industry Foundation Classes (IFC) files that can be produced directly from existing Building Information Modelling (BIM) software. The pycab tool enables industry professionals to make design stage decisions that reduce the embodied carbon impact of their projects. This research demonstrates one of the many potential uses that digital tools can have in reducing the environmental impact of the construction industry.

Web-based approach for systematic analysis and interactive visualization of the industry foundation classes data: a case study in duct design

ABSTRACT Existing model checkers of building information modeling (BIM) can open industry foundation classes (IFC) files and perform clash detection between mechanical, electrical, and plumbing (MEP) and architectural as well as structural models. However, there are few applications of IFC data in MEP engineering, specifically in interactive visualization between calculation results and BIM models. This study focuses on the systematic analysis of a BIM model and interactive visualization of IFC data for MEP engineering. First, the systematic analysis method for a ventilation system is proposed using the critical path class. Second, referring to the IFC relationship of connections between duct elements, elements in the same system are sorted into different levels of critical paths. Furthermore, ifcPressureViewer is developed based on the interactive visualization methodology by connecting Three.js, a JavaScript 3D library, with Echarts, a JavaScript visualization library, which is applicable for desktop computers and mobile tablets. This is followed by a case study that demonstrates the application of the interactive visualization process. Finally, the conclusions of this study are summarized, and directions for future research are discussed.

Framework for Developing IFC-Based 3D Documentation from 2D Bridge Drawings

Building information modeling (BIM) has been widely accepted in the industry and extensively used in supporting many construction tasks. In the government sector, the USDOT Federal Highway Administration (FHWA) has implemented building information modeling (BIM) for bridge construction. Hence, state DOTs are now faced with heightened pressure in complying with the FHWA’s Bridge Information Modeling (BrIM) standardization. Although BIM can provide many benefits to DOTs, current BIM-based platforms for bridges are not fully developed to process traditional two-dimensional (2D) bridge drawings for BIM-based computational tasks involving existing bridges, for example cost estimation. Bridges are a critical infrastructure in any nation’s economy, and by law the DOTs are tasked with ensuring that they remain safe for use. To maintain bridges, engineers currently perform periodic inspections, assessing each part of the bridge to identify areas that require maintenance. Maintenance work items are then generated for these areas; these are usually computed traditionally or by systems that still rely heavily on manual inputs. Such processes are time-consuming and cumbersome, and depend on years of bridge technical expertise. To overcome these limitations and improve the accuracy of processes such as generating maintenance work items for bridges, we propose a framework for automatically (1) processing existing 2D bridge drawings for bridges built pre-BIM adoption in the architecture, engineering, and construction (AEC) industry; (2) converting these record drawings into three-dimensional (3D) information models; and (3) converting 3D information models into industry foundation class (IFC) files. The developed 3D models using the proposed framework were compared against developed 3D models using the state-of-the-art method. Experimental results show that the developed framework can be used in developing algorithms that generate 3D models and IFC output files from portable document format (PDF) bridge drawings in a semiautomated fashion. The proposed method uses 3.33% of the time it takes the current state-of-the-art method to generate a 3D model, and the generated models are of comparative quality.

Visualizing UML’s Sequence and Class Diagrams Using Graph-Based Clusters

The paper discusses the creation of UML diagram based recommendation system using java and class files as the input. The existing systems do not make use of techniques available in text-mining for creating UML diagrams. The overall methodology makes use of keyphrase extraction, contextual similarity calculation, and graph-based clusters in creating UML diagrams. The existing systems survey of state-of-art UML diagram generation techniques and keyphrase extraction survey is also provided. A comparative analysis of the existing tools for generating UML-diagrams is also provided. The recommendation system generated is useful to maintenance engineers and software developers.

Selected tools for Java class and bytecode inspection in the educational environment

Abstract Java is not only a modern, powerful, and frequently used programming language, but together with Java Virtual Machine it represents a novel dynamic approach of writing and executing computer programs. The fact that Java programs are executed in a controlled environment has several important implications that define the nature of the language and makes it different from the traditional C-like languages. Knowing the detailed differences between the two types of languages and execution environments is a part of the holistic education of a computer engineer. In this paper, we present some behind-the-scene details about the Java Virtual Machine and we show how these details could be used in the educational process to demonstrate the differences and to emphasise the advantages of the dynamic programming approach when compared to the static one. After presenting some information about class files and about the internal structure and operation of the Java Virtual Machine we demonstrate the usage of public domain programs that could be used in the educational process to put these theoretical concepts into practice.

EFL Students Perspective towards Online Learning Barriers and Alternatives Using Moodle/Google Classroom during COVID-19 Pandemic

Covid-19 pandemic has made many countries adapt on new situations in different sectors including education. The Indonesia government has decided to adjust the education mode from face-to-face to online meeting using various learning management systems (LMS) such as moodle and google classroom. Moreover, the present research depicted the online learning barriers faced by students as well as their alternatives to cope them. The research implemented descriptive mixed-method survey design. The participants were 25 students of English Education Department. The instruments used to gather the data were the questionnaires and interview regarding the topics. The results showed that students experienced three barriers during the online learning including infamiliriaty of e-learning, slow internet connection, and physical condition e.g. eye strain. The alternatives they proposed were providing training to implement the LMS before the real class, converting high-definition or big-size files into smaller one, and giving break during the online class. The conclusion stated that students had to be creatives to find any solutions and innovations regarding learning barriers including maintaining good communication with teacher and understanding best learning styles individually

A study of the correctness of the execution of a class file with an embedded digital watermark in different environments

In this work, the authors set a goal of carrying out a complex study. Preparation of different types of environments and operating systems of different bit version is made. After that, preparation, creation, and embedding of a digital watermark in a class file of the program module written in Java take place. Creation and embedding of a digital watermark are carried out according to the method, previously developed by the authors and associated with the use of undocumented features of Java virtual machine. After all the steps, we execute the file on various platforms with different presets, and then we check if a digital watermark in a class file is nor overwritten nor destroyed and if the class file itself functions in the same way on all platforms. Among other things, the checks are performed to ensure that the digital watermark meets the previously defined criteria.

Revising canons of writing skills development in the academic setting: Towards a synergy of teacher and student creative effort

It is stipulated that the model of writing typically implemented in the academic context, with its traditional delineation of the respective roles of teacher as expert and student as imitator, demonstrates considerable limitations. Advocated in the article is its replacement through a paradigm of instruction which shifts its emphasis from the presentation of writing forms, genres and conventions of writing, and the evaluation of students’ texts with reference to the input models, to the teacher’s assistance, mediation and co-authorship in the students’ writing process. In this model, the aims of instruction go beyond the solitary pursuit of academic excellence to tap into learner creativity in a dynamic interactive classwork environment which acts as a stimulus to their individual composing and editing endeavours.
 Two pedagogic instruments underpin the model: the first is the student-executed Portfolio, comprising records of writing in the form of drafts and re-drafts, and the teacher’s interventions in and feedback on them; the second - the teacher-developed Class File, chronicling significant classroom activities and students’ written or spoken contributions, made available to the students after the lessons and serving as a link between the texts which have been generated and those which are still in the making.

Code Obfuscation. Where is it Heading?

Reverse Engineering is the process of revealing hidden code from class file. It converts garbage to readable English text. The main purpose of Reverse Engineering is to uncover the hidden code when the documentation is poor, missing source file, and developer is no longer available to provide the original code source file. Hacker uses Reverse Engineering to attack the class file to uncover the code. Then, the code can be reused for other purposes without taking any permission from the original author. The class file contains all the information and business rules that will be revealed once Reverse Engineering process attacks. Anti-Reverse Engineering techniques are developed to stop, delay, and prevent Reverse Engineering; one of the most common techniques is Obfuscation. It has many forms of protection such as, changing the names of classes and variables names, hide classes, and change form of code. In this paper, an appraisal will be conducted to study the current Obfuscation techniques. This research proposes a new hybrid technique that is based on obfuscation; the technique will be using mathematics, Unicode, and unknown language to convert the source file to a garbage running file that does same task which normal source file does for java applications.

Evaluation of Routing Protocols in Wireless Ad-Hoc Networks under Security Attacks

Wireless networks have certainly been are volution int oday’s technology as one of the most vital and active field sin the communication industries.These wireless ad-hoc networks consists of independent nodes with decentralized administration and physical infrastructures, also with a dynamic topology in which no descan easily leave or join the network at all time and also move freely. In other not to compromise the confidentiality ,availability and integrity of network services, the safety of packets data can only be achieved by guaranteeing that the problem of security has met the requisitest and ard.The performance analyses of routing protocols for Ad-Hoc wireless networks, DSDV, DSR and AODV were investigated using network parameters such as averages through put ,packet delivery ratio and End-to-end delay using various scenarios of mobile node and size of the network. A wk script was used to analyze the trace file and produce the average through put, packet delivery ratio and end-to-end delay as there sult of the simulation. The simulation was run by implementing code sin DSDV ,DSR and AODVCC class files to accommodate the behavioral pattern of attacks. In the results analysis of routing protocols under the security attacks, it was observed that the DSDV significantly has lower performance as are sult of frequent link changes and connection failure swhich led to heavy overload and congestion problems .Further more, when comparing the two reactive routing protocols, AODV performs better than DSR.

A COMPUTATIONAL FRAMEWORK FOR HOLISTIC LIFE-CYCLE DESIGN OF BUILDINGS

This paper combines building information modeling with advanced structural modeling to optimize the design of building components using a life-cycle perspective. A new object-oriented software framework that extends an existing program is presented. It creates information-rich finite element models from industry foundation class files that are exported from building information programs. In addition to models for structural responses, the new components contain models for construction cost, repair cost, environmental impact cost, and human health cost. Random variable objects represent uncertainties in material properties, hazards, and cost models. Similarly, design variable objects represent decisions, such as structural dimensions and materials. All costs are summed and the expected value of this sum is employed as a decision criterion. This paper presents the software framework and a demonstration application.