Collaborative CAD in Support of Engineering Design Reviews

A blockchain-based engineering design review service trading scheme for digital building permits

In this paper the realization method of collaborative CAD is introduced, How to synchronize model is one of the key technologies of achieving collaboration CAD. The incremental transmission algorithm of accurate CAD model based on changed primitives is presented for replicated collaborative CAD system in this paper, which reduces greatly amount of model data transmission during the process of collaborative CAD. This algorithm effectively achieves rapid transmission of the CAD model in synchronized collaborative design, and guarantees the synchronization of collaborative model.KeywordsCollaborative CADCAD ModelChanged PrimitivesReal Time Transmission

Supercritical water oxidation (SCWO) is an emerging technology for industrial waste treatment and is being developed for treatment of the US Department of Energy (DOE) mixed hazardous and radioactive wastes. In the SCWO process, wastes containing organic material are oxidized in the presence of water at conditions of temperature and pressure above the critical point of water, 374 C and 22.1 MPa. DOE mixed wastes consist of a broad spectrum of liquids, sludges, and solids containing a wide variety of organic components plus inorganic components including radionuclides. This report is a review and evaluation of tubular reactor designs for supercritical water oxidation of US Department of Energy mixed waste. Tubular reactors are evaluated against requirements for treatment of US Department of Energy mixed waste. Requirements that play major roles in the evaluation include achieving acceptable corrosion, deposition, and heat removal rates. A general evaluation is made of tubular reactors and specific reactors are discussed. Based on the evaluations, recommendations are made regarding continued development of supercritical water oxidation reactors for US Department of Energy mixed waste.

A novel CRDT-based synchronization method for real-time collaborative CAD systems

One difference between real-time CSCW systems and traditional distributed systems is that the former one needs to provide a natural, free and fast interface for multi-user interaction. However, typical multi-user interaction methods in 3D CAD systems apply strict consistency maintenance, such as lock mechanism and floor control which result in a stagnant and unnatural interface. This article proposes a semantic-based operational transformation (OT), which is similar to the traditional OT form, to support less constraint multi-user interaction and to achieve consistency in collaborative CAD editing (co-CAD) systems. Major technical contributions of this article include: a 3D semantic priority to select operations from waiting list, an OT strategy to decide OT direction, OT rules and a kernel OT function for co-CAD systems.

A new 3D platform is build in the self developed WebCAD system, used for multiple user collaborative design. As an extension of the WebCAD system, the collaborative 3D CAD system proposes a collaborative Boolean operation method. With the method complex physical objects can be easily obtained through Boolean operations of some elemental entities. With the new system, geographically distributed designers can design and edit 3D entities collaboratively on their own browsers. A three-tier architecture and an entity-based access control mechanism to settle confliction in collaborative design process are also employed in the system.

There are numerous examples of system developments which have not been entirely successful based on cost, schedule, and technical criteria. Many development problems have been traced to poor system requirements. This research introduces a user‐centered system development model which begins with user participation during the requirements elicitation phase. The Facilitator Assisted Requirements Elicitation (FARE) method is introduced, in which a technical facilitator acts as a neutral third party who bases discussion of requirements on concepts of operations (CONOPS) and use‐cases. User involvement continues throughout the system development lifecycle via participation in Integrated Product Teams, design reviews, and human‐machine interface reviews. End‐users take ownership of the System Requirements Specification (SRS); the system design; validation, transition, and training plans; and ultimately the delivered system.

In efforts to support the Artemis mission which seeks to return to the lunar surface, this research seeks to tackle one of the biggest issues faced on the lunar surface. Lunar soil is a hazardous threat to both spacesuit functionality and astronaut health. Due to characteristics such as being electrostatically charged, jagged edged and extremely fine in composition (> 10 microns). For the past three years the research focus has been experimenting with previously established electrostatic cleaning systems that were not able to achieve 100% cleaning efficiency. Removing soil particles smaller than 10 microns became a main concern as they were the most difficult to remove. Previous iterations were able to achieve up to 98% cleaning efficiency and building upon this success the research developed new methods of transmitting an electrostatic field by using thin films which are more beneficial to spacesuit fabric. The system during certain test pushed the limits by achieving a cleaning efficiency of 99.5%. This study discusses the process of using systems engineering to successfully take the system from inception to completion. This process illustrates the project progress during major reviews such as System requirements review, preliminary design review and critical design review. Also, the schedule and budget concept of operations and system hierarchy is discussed as it progressed throughout the project. Various trade studies, reliability and safety of the project is also examined in this study. The system is finally built and tested to display its feasibility and efficiency to match that which was envisioned during the inception of the project.

New, experimental, synchronous, multi-user CAD systems, such as BYU’s NXConnect, allow users to work together simultaneously in the same CAD model. Although multi-user CAD comes close to approximating the old collaborative drafting table experience, NXConnect still falls short in a few key areas, most notably of which is in collaboration awareness. This results in redundant work and lost time. Investigation was done with other multi-user software to see what features help each user to be aware of what is being worked on. This resulted in a proposed plugin for NXConnect consisting of two elements: a preview-based real-time feature update and a temporary plane indicating where a user is creating a sketch. Teams using NXConnect with and without the plugin were studied. Teams using the plugin found a small improvement in working collaboratively.

This paper presents an operation-based exchange mechanism for interoperability in heterogeneous CAD collaboration. The mechanism different from STEP-based exchange mechanism facilitates the engineers to exchange design information in distributed environment with shared semantic operations instead of model data, and to synchronously or asynchronously reconstruct the design process by executing the semantic operations in native CAD system. The proposed architecture based on this mechanism is developed to integrate traditional CAD systems and multimedia tools, and to provide essential collaborative support functions. The operation-based collaborative design system is applicable to many interactive design activities such as remote design review and online collaborative design.

In conducting collaborative research involving more than one researcher, a system is needed that can improve the performance of researchers in various ways. This study captures the challenges faced by researchers in collaborative research and defines the requirements for collaborative research systems needed to address these challenges. From the analysis of the needs obtained, the researchers designed a collaboration application interface. Collaboration applications are needed to facilitate communication between researchers, search for articles, share publications, and other applications. The distribution of questionnaires and interviews were conducted to obtain the requirements needed for the development of a collaboration system. This research informs system developers to support the development of collaborative systems. In this study, the level of need for a research collaboration system in the university environment will be analyzed along with an analysis of its needs and the design of the user interface.

Environmental and anthropogenic processes have led to widespread changes in productivities and spatial distributions of marine fishery resources. As geographic distributions of fish stocks and subsequently fishing fleets shift, improved spatiotemporal data and spatial modeling will become necessary to estimate abundance and productivity. The goal of this paper is to propose a strategy for engineering a modeling platform for spatially explicit, next-generation stock assessment models. We recount our approach for developing a system prototype, the Metapopulation Assessment System (MAS), that is easy to use, modular, and extensible. The MAS prototype was designed to support complex metapopulation modeling, which includes handling multiple populations, areas, fleets, and surveys and sex differentiation. We describe the components of the software life cycle, engineering, and infrastructure design to support a spatially explicit, next-generation stock assessment system. Software infrastructure was designed and implemented with 3 components: GitHub for collaboration, version control, and code organization; the C++ language for coding fishery system dynamics and estimation modeling; and the R language for coding the input-output interface and systematic testing. Systematic testing was a key component of the MAS development life cycle and was applied to guarantee that system requirements, such as accurate estimation of quantities of interest, are successfully implemented. We conclude with a discussion of some lessons learned and future challenges for ongoing efforts to implement a next-generation stock assessment platform.

General Electric, the National Renewable Energy Laboratory (NREL), the University of Massachusetts Amherst (UMass), and Glosten have recently completed a US Department of Energy (DOE)-funded research program to study technologies for mitigating loads on floating offshore wind turbines through the use of advanced turbine controls and tuned mass dampers (TMDs). The analysis was based upon the Glosten PelaStar tension leg platform (TLP) with GE Haliade 150 turbine, a system developed in a previous front end engineering design (FEED) study funded by the Energy Technology Institute (ETI) in the UK. The platform was designed for the WaveHub wave energy research site, with a mean water depth of 59-m. Loads were analyzed by running time-domain simulations in four 50-year return period (50-YRP) ultimate load state (ULS) conditions and 77 fatigue load state (FLS) environmental conditions. In 50-YRP conditions advanced controls are not active. The influence of TMDs on ULS loads have been reported previously (Park et al. [2]). In FLS conditions advanced controls and TMDs afford dramatic reductions in fatigue damage, offering the potential of significant savings in tower structural requirements. Simulations in turbine idling conditions were run in OrcaFlex, and simulations in operating conditions were run in FAST. Simulations were run with a baseline turbine controller, representative of the current state of the art, and an advanced controller developed by NREL to use collective and individual blade pitch control to maintain rotor speed and reduce tower loads. UMass developed a number of TMD types, with varying system configurations, including passive nonlinear dampers and semi-actively controlled dampers with an inverse velocity groundhook control algorithm. Loads and accelerations in FLS conditions were evaluated on the basis of damage equivalent loads (DELs), and fatigue damage was computed by Miner’s summations of stress cycles at the tower base. To study sensitivity to water depth, loads were analyzed at both the 59-m WaveHub depth and a more commercially realistic depth of 100 m. TMDs reduce fatigue damage at the tower-column interface flange by up to 52% in 59-m water depth and up to 28% in 100 m water depth. Advanced controls reduce fatigue damage at the tower-column flange by up to 22% in 59-m water depth and up to 40% in 100 m water depth. The most effective load-mitigation strategy is combining advanced controls with TMDs. This strategy affords a 71% reduction in fatigue damage in both 59-m and 100-m water depths.

Supporting group Undo/Redo with high performance in a 3D designing environment still remains a challenge. The question is how to recover the document state as if an operation is never executed. In this paper, we are going to propose an inverse-operation based group Undo/Redo solution for feature-based 3D collaborative CAD systems. It allows a 3D part to be manipulated locally. We developed an ontology in the CAD domain so as to describe common elements in typical feature-based CAD systems. By classifying features according to how they affect a volume, feature modeling operations are categorized into four groups. We are able to create inverse operations for operations belonging to the same category. The proposed methods are tested in a prototype system with case study.

Nowadays a lot of enterprises develop the products collaboratively using heterogeneous CAD systems. Feature based data exchange and interoperation among heterogeneous CAD systems are very important in pervasive computing environments. The key techniques in feature based data exchange are feature retrieval (extraction) and feature reuse (reconstruction). This paper presents a direct approach for feature retrieval and feature reconstruction. At first, most of feature information is directly retrieved by first retrieval mechanism in source systems. Then, the secondary retrieval mechanism acquires related information which can not be retrieved in first retrieval. At last the feature model is reconstructed one by one accurately in target systems by the model reconstruction mechanism.