Computer-aided Drawings Research Articles

Artificial intelligence-enabled evaluating for computer-aided drawings (AMCAD)

AMCAD ( www.amcad.ai ) is a web-enabled artificial intelligence (AI) system created to auto-evaluate students’ computer-aided drawing (CAD) work assignments and help students in self-directed learning. It compares two engineering drawings and highlights the differences (errors) between the two. The errors are classified into two categories: “Missing Line” errors shown in red and “Erroneous Line” errors in blue. AMCAD works in tandem with all CAD software. It uses computer vision technology to convert PDF drawings to raster subimages, and XOR to evaluate quantitatively the best-matched with best-aligned views. AMCAD, whose AI algorithms and web application were developed in Python, shows the comparison results in two display modes: superimpose and side-by-side. To encourage students in self-directed leaning, instructional videos can be included in each CAD work assignment.

Creating digital twins from computer drawings and laser scans: a comparison

Building information models offer significant advantages in managing existing buildings and infrastructure. If no such ‘digital twins’ exist, they can be generated from two-dimensional computer-aided design drawings or from laser scanning photogrammetry. This paper starts by describing and comparing the two methods of model generation. It then reports on a study where both methods were used to model a university building complex in Turkey. The results are compared and discussed, highlighting their respective advantages and disadvantages. It is concluded that the ideal solution is a combination of elements of both methods.

Structure Integrity Analysis Using Fluid–Structure Interaction at Hydropower Bottom Outlet Discharge

Dam reliability analysis is performed to determine the structural integrity of dams and, hence, to prevent dam failure. The Chenderoh Dam structure is divided into five parts: the left bank, right bank, spillway, intake section, and bottom outlet, with each element performing standalone functions to maintain the overall Dam’s continuous operation. This study presents a numerical reliability analysis of water dam reservoir banks using fluid–structure interaction (FSI) simulation of the bottom outlet structures operated at different discharge conditions. Three-dimensional computer-aided drawings were used to view the overall Chenderoh Dam. Next, a two-way fluid–structure interaction (FSI) model was developed to explore the influence of fluid flow and structural deformation on dam systems. The FSI modeling consists of Ansys Fluent and Ansys Structural modules to consider the boundary conditions separately. The reliability and performance of the reservoir bottom outlet structure was effectively simulated and recognised using FSI. The maximum stress on the bottom outlet section is 18.4 MPa, which is lower than the yield stress of mild steel of 370 MPa. Therefore, there will be no structural failure being observed on the bottom outlet section when the butterfly valve is fully closed. With a few exceptions, the FSI models projected that bottom outlet structures would be able to run under specified conditions without structural collapse or requiring interventions due to having lower stress than the material’s yield strength.

A standard electrolyzer test cell design for evaluating catalysts and cell components for anion exchange membrane water electrolysis

Anion exchange membrane water electrolysis technology is an environmentally friendly method for hydrogen production without carbon dioxide emissions. The development of this technology is hindered by the sluggish rates of the hydrogen and oxygen evolution reactions, demanding the rational design of electrocatalysts for these processes. Although numerous hydrogen and oxygen evolution electrocatalysts are reported in the literature, there is currently no standard set of conditions or cell design under which they can be tested; variance in testing conditions and water electrolyzer components from one study to another therefore hampers a full and coherent comparison of novel electrocatalysts for anion exchange membrane water electrolysis. Herein, a standard water electrolyzer test cell was designed and optimized, such that this test cell can be adopted as a universal framework for evaluating novel electrocatalysts (and indeed other cell components) for anion exchange membrane water electrolysis. The performance of this water electrolyzer was evaluated using a commercial Pt/C hydrogen evolution reaction electrocatalyst, with an optimized cell found to deliver current densities of 1.40 A cm–2 and 2.74 A cm–2 at cell voltages of 2.0 V and at 60 °C using Fumasep FAA-3-50 and Sustainion® X37-50 membranes, respectively. Guidance for assembling and operating the water electrolyzer is provided, along with computer-aided design drawings of the electrolyzer and its components to allow others to construct their own identical cells for benchmarking catalysts and other cell components for anion exchange membrane water electrolysis.

Supplementary open dataset for WiFi indoor localization based on received signal strength

Several Wireless Fidelity (WiFi) fingerprint datasets based on Received Signal Strength (RSS) have been shared for indoor localization. However, they can’t meet all the demands of WiFi RSS-based localization. A supplementary open dataset for WiFi indoor localization based on RSS, called as SODIndoorLoc, covering three buildings with multiple floors, is presented in this work. The dataset includes dense and uniformly distributed Reference Points (RPs) with the average distance between two adjacent RPs smaller than 1.2 m. Besides, the locations and channel information of pre-installed Access Points (APs) are summarized in the SODIndoorLoc. In addition, computer-aided design drawings of each floor are provided. The SODIndoorLoc supplies nine training and five testing sheets. Four standard machine learning algorithms and their variants (eight in total) are explored to evaluate positioning accuracy, and the best average positioning accuracy is about 2.3 m. Therefore, the SODIndoorLoc can be treated as a supplement to UJIIndoorLoc with a consistent format. The dataset can be used for clustering, classification, and regression to compare the performance of different indoor positioning applications based on WiFi RSS values, e.g., high-precision positioning, building, floor recognition, fine-grained scene identification, range model simulation, and rapid dataset construction.

Automated structural design of shear wall structures based on modified genetic algorithm and prior knowledge

Shear wall layout requires repetitive revisions and checks by an experienced designer, which is very time-consuming and inefficient. Therefore, an automated and effective approach to structural design of shear wall structures is needed. An automated generation method of structural model from architectural computer-aided design drawings is described, where the semantic segmentation of buildings based on the connected component analysis, graph structure and Procrustes analysis and an effective parametric modeling approach of shear wall structures integrated with prior knowledge are included. Besides, a modified genetic algorithm with greedy strategy is suggested for shear wall layout optimization. The proposed approach is shown to be effective and reliable through two real-world examples, demonstrating the promising future of automated structural design. This study addressed only the earthquake-resistant design of buildings, and other relevant issues such as beam layout optimization, multi-objective optimization, and economic feasibility of construction should also be addressed in the future.

ОБГРУНТУВАННЯ ВИКОРИСТАННЯ МЕТАЛУРГІЙНИХ ШЛАКІВ ЯК ЗАКЛАДНОГО МАТЕРІАЛУ КАР’ЄРНИХ ПУСТОТ

Purpose. Experimental studies of the interaction of blast-furnace and steel-making slags with open pit waters during their direct contact and assessment of the volume of filling of the formed man-made cavities during mining of mineral deposits. Methods. Based on the analysis, the current low level of metallurgical slag and the lack of real and effective directions of their large-scale utilization were determined. The laboratory studies of the interaction of metallurgical slags with open pit water at a certain time of interaction, generally accepted methods for studying the chemical composition and concentration of substances in water, computer-aided design software packages and drawings to determine the volumes of the open pit mined-out area were used. Results. The dynamics of changes in the products of interactions of steel-smelting slags with open-pit waters at a certain ratio and period of interaction was investigated. It was found that the concentration of pollutants upon contact of water with steel-making slag changes according to polynomial dependences on the time of their interaction, decreasing by the 30th day, which eliminates the danger for the aquifer. The safest type of metallurgical slag was recommended for the formation of the bottom layer of the backfill massif. The volumes of the mined-out area of the open pit were determined in detail to assess the volumes of placement of the backfill material based on metallurgical slags. Scientific novelty. The safety of the contact of backfill materials based on steelmaking slags with open pit water was scientifically proven, which is confirmed by the established polynomial patterns of changes in concentrations and pollutants from the ratio and time of interaction. Practical significance. The formation of the backfill massif on the basis of blast-furnace dump and steel-smelting slags will allow achieving an environmental effect, such as their safe disposal as a reclamation of technologically disturbed lands by mining and restoration of the economic value of the land plot, as well as preventing the formation of new dumps.

Designing a 3D Printed Prosthetic to Meet Task-Specific Needs: A Case Study

The purpose of this case study is to explore the ease of utilizing task-specific design in computer-aided, open-source 3D printed design software. Two participants were recruited and assessed using subjective and objective measures to guide the prosthetic designs. Hand measurements were obtained and entered into computer software to create computer-aided design drawings of the digit prosthetics. Field notes were taken throughout this process by the interdisciplinary team and analyzed to address the ease of utilizing this technology. Objective assessments showed that both participants experienced decreased expansion, grip, and prehension strength of their affected hands. Semi-structured interviews with the participants identified several meaningful tasks that a prosthetic device could improve function in and offered valuable guidance in the development of the prosthetic designs. Analysis of the field notes allowed for the identification of six domains within the research questions. Those domains include appropriate assessment utilization, time management, participant responsiveness, clinical reasoning, common language, and available resources. The successful collaboration of occupational therapy (OT) and engineering disciplines resulted in customized 3D printed finger prosthetic designs to meet participants' specified tasks.

A Grammar of Muqarnas: Drawings of the Alhambra by Jones and Goury (1834-1845)

<p>The muqarnas of the Nasrid Alhambra stand out as one of the most singular architectural episodes of Medieval Islamic art due to their sophisticated three-dimensional construction, whose layout remains little known. In 1834 and 1837, the architects Owen Jones and Jules Goury visited the monument in Granada and accomplished surprising drawings thereof, later published towards 1842-1845 as chromolithograph prints, which represented its architecture, ornaments, and muqarnas in a systematic way for the first time. In order to value their pioneering drawings, the historical data is briefly reviewed and several previous drawings of the Alhambra are cited. After consideration of a few questions regarding the process of data collection in Granada, a comparative analysis is presented of a cornice, a capital, an arch and a pendentive, with photos and computer-aided drawings. Thus, the principles or elementary grammar of muqarnas groupings described by these architects are highlighted, as well as the precision of their images, which resulted crucial to integrate and disseminate the architectural legacy of the Alhambra in the contemporary Western culture.</p>

An Automated Approach to Building and Simulating Dynamic District Heating Networks

In Nordic countries, district heating accounts for a large share of the consumers’ heat demand. In Sweden, roughly 50% of the total heat demand is attributed to district heating. Which, over the past few years, is equivalent to around 50 TWh, and imposes a difficult balance between supply and demand for the suppliers of district heating. For large networks the propagation of heat from supplier to end-user can vary several hours. Further complexities of large networks, which can consist of multiple overlapping rings, is that during transient conditions the flow can actually change direction. A dynamic modeling library has been developed in Modelica using OpenModelica for district heating networks. Methods for modeling, handling data, simulating and the visualization of results has been developed using Matlab. The model has been validated using data from Mälarenergi AB, a local provider of district heating in Västerås, Sweden. The model provides to an acceptable degree in predicting the heat propagation and temperature distribution in a localized case study. Adding a higher level of robustness, the model has the capacity to handle bi-directional and reversing flows in complex ring structures. Through this work, the combination of OpenModelica and Matlab, a framework for automating the building and simulation of district heating networks is obtainable. The implications of automating network modeling from computer-aided design drawings allows for a quick robust overview of how the network is working and how prospective additions to the network could impact the end-users. Furthermore, incorporating visual aspects for heat propagation in a network contributes to a higher understanding of complex network structures.

From Design to Production: An Integrated Methodology to Speed Up the Industrialization of Wooden Hulls

A new design and construction procedure for manufacturing wooden boats is presented, based on modular, parameterized components produced by computer numerical control (CNC) machining. This semiautomated procedure greatly reduces time requirements for vessel assembly compared with traditional methods and yields similar economic viability to other less sustainable materials such as fibreglass. Starting from computer-aided design drawings, the three-dimensional geometry is optimized considering target functions (resistance, dynamics…). Segmentation of wooden strips and transformation into two-dimensional segments permits to simplify CNC machining, with component borders shaped and tapered for better interconnection. Tool path generation is part of the cutting procedure to achieve the required components with the minimum use of raw materials and operational time. All strips, together with the frame, are manufactured using a 5-axis CNC machining center and finally assembled to produce the first industrialized prototype of wooden boat. Manufacturing in this way represents a significant step toward viable mass production of wooden boats. 1. Introduction The application of modem manufacturing techniques to the production of wooden boats has the potential to revitalize the use a cheap and environmentally sustainable material in the boating industry. Such a consideration is particularly relevant in the current global context of economic downturn and climate change. Historically, the use of wood (as in [Lanapoppi 2000, Howorth 1980]) was phased out in favor of materials that were cheaper and simpler to deal with, such as fiber-reinforced composites and aluminium (Espeut 1983). The use of wood was inherently manual (Fig. 1) and time consuming, leading to lower economic viability. The widespread adoption of fiberglass eventually came due to its superior malleability and strength-to-weight ratio, as well as its potential to reduce manual labor requirements during construction (Fox 2001). Several decades later, the needs of both manufacturers and customers alike have changed. Natural materials, zero-impact boating and embodied energy are now regular subjects of discussion in the literature (Guamán et al. 2015). The use of wood and electric-solar drivetrains are common approaches when striving for a negative carbon footprint (Pommier et al. 2015). Increasing attention on environmental sustainability, together with several recent changes in wood production technology, suggest the necessity for reevaluation of resource use in boatbuilding, with emphasis placed on environmental sustainability.

Evaluation of Three Sources of Validity Evidence for a Synthetic Thoracoscopic Esophageal Atresia/Tracheoesophageal Fistula Repair Simulator.

Thoracoscopic esophageal atresia (EA)/tracheoesophageal fistula (TEF) repair is technically challenging. We have previously reported our experiences with a high-fidelity hybrid model for simulation-based educational instruction in thoracoscopic EA/TEF, including the high cost of the tissue for these models. The purposes of this study were (1) to create a low-cost synthetic tissue EA/TEF repair simulation model and (2) to evaluate the content validity of the synthetic tissue simulator. Review of the literature and computed tomography images were used to create computer-aided drawings (CAD) for a synthetic, size-appropriate EA/TEF tissue insert. The inverse of the CAD image was then printed in six different sections to create a mold that could be filled with platinum-cured silicone. The silicone EA/TEF insert was then placed in a previously described neonatal thorax and covered with synthetic skin. Following institutional review board-exempt determination, 47 participants performed some or all of a simulated thoracoscopic EA/TEF during two separate international meetings (International Pediatric Endosurgery Group [IPEG] and World Federation of Associations of Pediatric Surgeons [WOFAPS]). Participants were identified as "experts," having 6-50 self-reported thoracoscopic EA/TEF repairs, and "novice," having 0-5 self-reported thoracoscopic EA/TEF repairs. Participants completed a self-report, six-domain, 24-item instrument consisting of 23 5-point rating scales and one 4-point Global Rating Scale. Validity evidence relevant to test content and response processes was evaluated using the many-facet Rasch model, and evidence of internal structure (interitem consistency) was estimated using Cronbach's alpha. A review of the participants' ratings indicates there were no overall differences across sites (IPEG versus WOFAPS, P=.84) or experience (expert versus novice, P=.17). The highest observed averages were 4.4 (Value of Simulator as a Training Tool), 4.3 (Physical Attributes-chest circumference, chest depth, and intercostal space), and 4.3 (Realism of Experience-fistula location). The lowest observed averages were 3.5 (Ability to Perform-closure of fistula), 3.7 (Ability to Perform-acquisition target trocar sites), 3.8 (Physical Attributes-landmark visualization), 3.8 (Ability to Perform-anastomosis and dissection of upper pouch), and 3.9 (Realism of Materials-skin). The Global Rating Scale was 2.9, coinciding with a response of "this simulator can be considered for use in neonatal TEF repair training, but could be improved slightly." Material costs for the synthetic EA/TEF inserts were less than $2 U.S. per insert. We have successfully created a low-cost synthetic EA/TEF tissue insert for use in a neonatal thoracoscopic EA/TEF repair simulator. Analysis of the participants' ratings of the synthetic EA/TEF simulation model indicates that it has value and can be used to train pediatric surgeons, especially those early in their learning curve, to begin to perform a thoracoscopic EA/TEF repair. Areas for model improvement were identified, and these areas will be the focus for future modifications to the synthetic EA/TEF repair simulator.

Working Away

This article discusses the evolving trend of mobile applications and their increasing use by engineers. With the help of mobile applications for smartphone and tablet, engineers are discovering innovative ways to work that don’t have them tied to their desks. Apps allow engineers to bring drawings with them while on the road, to collaborate with other engineers, and to access information on the shop floor or in the field. Due to the very nature of the mobile platform on which they sit, applications can’t be used at every job. Their adoption depends on the type of work, the work environment, and employees’ attitude. If enough employees do have their own personal devices, there are apps that let employers update employees on the shop floor or in the field. Many engineers use mobile applications to collaborate with their design-team members or to show others, like customers or suppliers, how a product will look or will function. Engineers can also share computer-aided design drawings, design work, spec sheets, and the like through the technology.

Modeling of transport phenomena during the coaxial laser direct deposition process

Laser direct deposition is widely used for rapid freeform fabrication of fully dense components with good metallurgical properties directly from computer-aided design drawings. Because of complex physics involved such as laser powder interaction, laser substrate interaction, track interface evolution, and melt-solid interaction, it is important to develop simulation models to better understand the characteristics and mechanisms in the process so that optimization and control of a laser direct deposition process are possible. In this paper, a new comprehensive three-dimensional self-consistent transient model is presented for a coaxial laser direct deposition process, which considers physical behaviors such as laser particle interaction, mass addition, heat transfer, fluid flow, melting, and solidification. A continuum model is built to deal with different phases (gas, liquid, solid, and mushy zone) in the calculation domain. An improved level-set method, which takes the conservative form while being implicitly solved with other governing equations, is proposed to track the evolution of free liquid/gas interface during the deposition process. To make the model more physically complete than those in the literature, a newly derived mass source term, which considers the rate of the gas phase being replaced by the deposited material due to the moving interface in some control volumes, is incorporated into the continuity equation. Corresponding new source terms of enthalpy and momentum due to the moving interface are also derived and embedded in the energy and momentum equations. The governing equations are discretized using the finite volume approach to better predict the fluid motion mainly driven by capillary and thermocapillary forces. The simulated track heights, widths, molten pool depths, and track profiles agree well with the experimental results.

Applying Handheld Computers in the Construction Industry

Handheld computers are becoming more powerful and their application to construction projects is becoming increasingly feasible. Wireless connectivity allows handheld computers to access the Internet for Web-browsing and data transfer. Potential construc- tion handheld computer applications include data collection, electronic books and reference materials, access to computer-aided design drawings, estimating, and scheduling applications. Mobile construction applications can be differentiated into two categories. They are general applications that can be used on many projects, and project-specific applications that must be tailored to a specific project. The capabilities of the two most popular handheld devices, the Palm and Pocket PC devices, are discussed and compared. The potential and costs of using handheld devices for Web access are discussed. A prototype Palm Web-clipping application is described. The capabilities of commercially available software packages and several prototype construction applications are discussed.

Computer-assisted construction methods knowledge management and selection

The construction industry's information environment is undergoing rapid changes. Construction professionals now expect fast and reliable access to rich data sources. Significant advances have been made in streamlining the creation and dissemination of computer-aided design drawings and construction documents through incorporation of information technology in the workflow. However, there is a need to go beyond just the automation of existing paper flows and provide the construction knowledge worker with tools that can be easily used to document previous project experience, track new technological developments, and then incorporate these in the formulation of construction strategies for future projects. This paper describes work aimed at creating such tools in the context of a comprehensive decision-support system, by developing intelligent representation structures for storing and accessing construction domain knowledge and coupling them with advanced planning tools so as to enable the quick formulation and assessment of initial project plans. The information requirements and features needed for such a system are first examined, followed by a demonstration of how some of these requirements have been addressed in the system design and implementation. Aspects of a hypothetical high-rise building project are used throughout to illustrate application of the concepts developed.Key words: construction methods, integrated project management systems, methods feasibility reasoning, hierarchical scheduling, project views.

Comments on "A Collaborative Investigation of the Line: Interactive Computer-Aided Drawings"

Comments on "A Collaborative Investigation of the Line: Interactive Computer-Aided Drawings"

A Collaborative Investigation of the Line: Interactive Computer-Aided Drawings

A Collaborative Investigation of the Line: Interactive Computer-Aided Drawings