Top-down Design Process Research Articles

IDENTIFYING AND COMPARING SUBPROBLEMS IN FACTORY DESIGN PROCESSES

AbstractWhen a design team faces the problem of designing a complex system, they are required to make several decisions. Because such design problems are difficult to solve all at once, teams often decompose the design problem into several smaller subproblems. This paper discusses the results of a study designed to understand how design teams decompose a factory redesign problem into sets of related subproblems and compare the subproblems obtained for each design team. This exploratory study analyzed the design activities of eight teams of professionals and used clustering to group the variables that the design teams considered. We found that the design teams used different decomposition strategies and different subproblems, but they more often considered subproblems with design variables of the same type, and some teams followed a top-down design process.

Research related to the Appearance Design of Water Surface Cleaning Robot based on Bionics

This thesis analyzes five representative water cleaning robots selected from three countries and combines the top-down design process of bionics and the basic elements of product design to clarify the problematic points of existing water waste cleaning robots and propose a bionic design solution. The results of the analysis show that the shape design is not optimized according to the shape of the hull, and the environmental and aesthetic aspects are not satisfactory. By applying the three bionic principles of color, form and material to the appearance of the robot, a robot that meets the needs of cleaning small urban waters is designed and derived. This proposal is an optimized solution to solve the existing defects of the product and complete the solution that meets the modern market demand, aesthetic patterns, and production methods.

A knowledge-based automated design system for mechanical products based on a general knowledge framework

In the field of mechanical product design, there have been difficulties in building a general model to represent a design process since the type of mechanical products is diverse and the design process requires different complex domain knowledge. This results in the need for different domain experts to design special system development schemes for different kinds of mechanical products, which greatly increases the cost of the research and development. In addition, there have been difficulties in the automation, intellectualization and acceleration of mechanical product design process, as the process is based on experiential knowledge and relies extensively on the synthetic decision of experts (SDE), which is hard to be integrated into the design process without the participation of experts in person. To cope with these two issues, a knowledge-based automated design (KAD) system for mechanical products was developed in this study. Firstly, a general feature design flow (GFDF) framework was proposed to represent the design knowledge of various mechanical products from initial design stage, including requirement analysis, to the final automated generation of computer-aided design (CAD) model. Based on parametric technology and application programming interface (API) functions, the GFDF framework decomposes the explicit and implicit knowledge of a top-down design process into four rank-correlated features and two feature correlation matrices (FCMs) respectively. Based on the GFDF framework, a requirement analysis method using analysis hierarchy process (AHP) was proposed to transfer qualitative features to quantitative parameters. Secondly, by adopting the support vector regression (SVR) machine, a feature reuse case adaptation (FR-CA) method based on case-based reasoning (CBR) was proposed to achieve the automation and intellectualization of parameter solving integrating the SDE without the actual participation of experts. The FRCA method transforms the SDE into an FCM, which can be identified during the case adaptation process, and maximizes the utilization of solved features in each adaptation process. A comparison experiment between FR-CA and conventional method for case adaptation indicated that the adaptation performance of FR-CA method is better than that of the conventional one. Finally, the KAD system was applied to the design of corn huskers. The result showed that the KAD system could improve the automated, intelligent and rapid design of mechanical products.

Technology to Support Aging in Place: Older Adults' Perspectives.

The U.S. population over 65 years of age is increasing. Most older adults prefer to age in place, and technologies, including Internet of things (IoT), Ambient/Active Assisted Living (AAL) robots and other artificial intelligence (AI), can support independent living. However, a top-down design process creates mismatches between technologies and older adults’ needs. A user-centered design approach was used to identify older adults’ perspectives regarding AAL and AI technologies and gauge interest in participating in a co-design process. A survey was used to obtain demographic characteristics and assess privacy perspectives. A convenience sample of 31 retirement community residents participated in one of two 90-min focus group sessions. The semi-structured group interview solicited barriers and facilitators to technology adoption, privacy attitudes, and interest in project co-design participation to inform technology development. Focus group sessions were audiotaped and professionally transcribed. Transcripts were reviewed and coded to identify themes and patterns. Descriptive statistics were applied to the quantitative data. Identified barriers to technology use included low technology literacy, including lack of familiarity with terminology, and physical challenges, which can make adoption difficult. Facilitators included an eagerness to learn, interest in co-design, and a desire to understand and control their data. Most participants identified as privacy pragmatics and fundamentalists, indicating that privacy is important to older adults. At the same time, they also reported a willingness to contribute to the design of technologies that would facilitate aging independently. There is a need to increase technology literacy of older adults along with aging literacy of technologists.

Design for energy efficiency in early stages: A top-down method for new product development

Designfor energy efficiency (DfEE) is highly valued in improving the energy efficiency during product use and the decisions with a significant impact on the product’s energy-efficiency performance are made during early design stages. The product’s design features determined in early design stages are hierarchical in nature and the design process for new products is generally top-down. However, current DfEE methods tend to firstly improve the design features on the bottom level and then the higher level till the energy-efficiency target is achieved. The contradiction between the top-down design process and the bottom-up energy-efficiency improvement severely limits the innovation in new product design and hinders the emergence of highly energy-efficient products. In addition, the energy-efficiency improvement is divergent and can generate a large number of solutions, but the design process needs to be convergent and arrives at a few or a single best solution. This paper proposes a top-down DfEE method called three-step cyclic design method for new product development in early design stages. It is based on a spiral design process and a three-layer framework of DfEE activities. The former supports a top-down approach for energy-efficiency improvement, and the latter ensures a convergent DfEE process. The implementation of this method is detailed through a case study of a wind turbine.

ToPoliNano: A CAD Tool for Nano Magnetic Logic

In the post-CMOS scenario, field coupled nanotechnologies represent an innovative and interesting new direction for electronic nanocomputing. Among these technologies, nanomagnet logic (NML) makes it possible to finally embed logic and memory in the same device. To fully analyze the potential of NML circuits, design tools that mimic the CMOS design-flow should be used for circuit design. We present, in this paper, the latest and improved version of Torino Politecnico Nanotechnology (ToPoliNano), our design and simulation framework for field coupled nanotechnologies. ToPoliNano emulates the top-down design process of CMOS technology. Circuits are described with a VHSIC hardware description language netlist and layout is then automatically generated considering in-plane NML (iNML) technology. The resulting circuits can be simulated and performance can be analyzed. In this paper, we describe several enhancements to the tool itself, like a circuit editor for custom design of field coupled nanodevices, improved algorithms for netlist optimization and new algorithms for the place and route of iNML circuits. We have validated and analyzed the tool by using extensive metrics, both by using standard circuits and ISCAS’85 benchmarks. This contribution highlights the improvements of ToPoliNano, which is now a innovative and complete tool for the development of iNML technology.

Multi-skeleton model for top-down design of complex products

Generally, there are two alternative design approaches available to engineers: bottom-up and top-down. Considering the sharp increase in the complexity of most mechanical products, the top-down design approach is more widely adopted in the development of complex products. However, in traditional top-down design process, design parameters are communicated through single-skeleton models, and design units are strongly coupled due to the multi-dimensional complexity of products. Toward this end, a new top-down design approach based on multi-skeleton model is proposed in this article. First, in accordance with different kinds of design parameters, three major skeleton models are defined, including location skeleton model, published skeleton model, and design skeleton model. And the characteristics of multi-skeleton models are also described. Then, the top-down design process based on the multi-skeleton model is explored, especially in the multi-skeleton modeling phase. It is also illustrated in detail that how to realize design parameter transmission and design unit reuse. Subsequently, it elaborates the communicating way and structure optimization of design parameters to support parameters controlled publishing and design units reuse. Finally, a meteorological satellite and a crawler crane design cases are implemented to expound the feasibility and effectiveness of the proposed framework.

Computational design of solid-state interfaces using O-lattice theory: An application to mitigating helium-induced damage

Tailoring interface structure to control interface properties promises to improve performance in a wide range of structural materials. We demonstrate an approach for designing interfaces with pre-specified internal structure and functionality using O-lattice theory. To illustrate our method, we design an interface intended to mitigate helium (He)-induced damage by promoting precipitation of He into continuous linear channels. A similar top-down design process may be used to tailor interfaces for other applications such as improved mechanical properties.

An integrated top-down design process evaluation approach of complex products and systems based on hierarchical design structure matrix

To enable a more optimised process model to effectively support the complex product and system (CoPS) development, the hierarchical design structure matrix (HDSM) is refined from the traditional design structure matrix to exhibit the correlative iterations and structure-evolvement within design activities. When implementing a top-down design process, the required modelling method is engraving with the traits, which are of great consideration through the decomposition of design activities, of hierarchy, coupling and complexity. Explored in this paper is an integrated evaluation approach based on the HDSM with emphasis on its application for supporting the top-down design process of CoPS. After the dependence degree between different levels in the top-down design process is analysed when the HDSM constructed, a concordant method based on triangular fuzzy number converts binary matrix design to the weighted form representing the coupling strength. Purpose served in this approach, including strengthening the internal polymerisation and sorting, can be demonstrated among design activities. The relevant issues having been developed and the coupling analysis implemented, the effectiveness and potential of the proposed approach is highlighted through a real-world case dealing with the development of a large tonnage crawler crane.

A top-down biomimetic design process for product concept generation

A top-down biomimetic design process for product concept generation

A top-down biomimetic design process for product concept generation

A top-down biomimetic design process for product concept generation

Top-Down Modularization Using Extensible Skeleton Model

By combining modular design with top-down design, a composite design method is proposed in this paper, namely top-down modularization. This design synthesis is achieved based on extensible skeleton model (XSM). XSM is developed oriented to design reuse by integrating traditional skeleton model with useful knowledge, resources, processes, et al. According to the characteristic of multilevel structure of products, a hierarchy framework of XSM is built. In addition, the top-down modular design process based on XSM is established. A design case of a typical two-axis servo mechanism is studied to illustrate as well as to demonstrate the validity of the method.

Grading in histopathology

Grading is the process of subdividing a diagnostic category to increase the amount of information in a histopathology report and so assist clinicians in making individual therapeutic decisions. A good grading system will have a high signal to noise ratio with good inter- and intra-observer agreement. Many grading systems in histopathology have been produced by a top-down design process which does not take into account the natural distribution of cases. Such systems may produce very poor results if the arbitrary boundaries of the grading system do not coincide with the natural boundaries of clusters of cases. This review examines the fundamental processes involved in grading and demonstrates bottom-up design processes which have the potential to produce effective grading systems.

Multi-level assembly model for top-down design of mechanical products

To enable next generation CAD tools to effectively support top-down design of products, a top-down assembly design process is refined from the traditional product design process to better exhibit the recursive-execution and structure-evolvement characteristics of product design. Based on the top-down assembly design process, a multi-level assembly model is put forward to capture the abstract information, skeleton information and detailed information involved. The multi-level assembly model is a meta-level implementation and is easy to be extended. Moreover, the inheritance mechanisms are explored to ensure the feasibility of information transferring and conversion between different design phases in the top-down assembly design process. A top-down assembly design sample is analyzed at length to show the application effects of the multi-level assembly model and the relevant inheritance mechanisms. In addition, a practical topic about the model adaptation of existing CAD systems is also discussed for a broader application of the top-down assembly design. Finally, the conclusion of the work and the future directions for further exploration are given.

Integrated Approaches for Generating Principle and Structural Innovation Concepts of Mechanical Products

A large number of decisions are made during the stage of concept design which is characterized by a lack of complete information.While existing computer aided design(CAD) systems for supporting the structure design have little impact at the conceptual design stage.To support the top-down design process,reduce the time of mechanical product design and ensure their innovation, a novel approach of the principle and structural conceptual design for mechanical products was presented in this paper.Firstly,the state equation,which is used to solve the principle concept,was established,and the gene-sign expression and corresponding algebra of the principle concept was also provided. Secondly, the structural state equation composing a machine was established,the spatial configuration model of function and assembly symbol was also proposed using in structural conceptual design.Finally,Based on the approach,corresponding software prototype was developed,a lot of concepts was generated successfully using this software prototype.The difficult problem merging the conceptual design and the detailed design is solved,thus it is a practical top-down design.

Web-based modular interface geometries with constraints in assembly models

The use of a modular technique in modeling for assembly can improve design efficiency and reduce the cost of product development. This paper presents an approach to an assembly model that was built using modular interface geometries. This paper proposes a novel, hybrid modular design strategy instead of the traditional, top-down design process. The curve-joint method is used as a simplified process for converting a 3D solid model to a skeleton model with interface geometries in modeling for assembly. This research builds assembly interface geometries with their constraints in the assembly model instead of using information about individual assembly parts for the product. These interface geometries are easy to share, and they deliver the design requirements properly. They also ensure that minimal efforts will be required in the design change process. By implementing this method, the constraints of the features in modular assembly parts can be transferred to interface geometries. Designers can easily add, replace, and delete design parts in the modular product. Module interaction for application programmed interface (MIAPI) is developed using HTML and JavaScript. The module structure of products can be verified via the web-based Internet in VRML format. These simplified assembly models that have fewer constraints allow design project managers to simulate the functioning of the product in the modularized design before the prototype is built. By using the assembly models, customers can easily choose various modules to assemble the exact products they are seeking via the Internet process. A desk lamp model is used as the example for implementation to validate the feasibility of this research.

Development of an integrated-collaborative decision making framework for product top-down design process

A process model based on product function and physical topology structure is proposed. This model decomposes the product top-down design process into module design task, part design task, design parameter and dependencies among them. According to the characteristics of the design process, an integrated collaborative design software framework is designed, which includes module task agent, part task agent and sensitivity-based collaborative design method for agents. The system is developed with Java and Web technologies and applied to the transmission design case to demonstrate its utilization and efficiency.

Integrated collaborative decision-making for product top-down design process

A process model based on product function and physical topology structure is proposed. This model decom-poses the product top-down design process into module design task, part design task, design parameter and dependencies among them. According to the characteristics of the design process, an integrated collaborative design software framework is designed, which includes module task agent, part task agent and sensitivity based collaborative design method for agents. The system is developed with Java and Web technologies, and applied to gear box design case to demonstrate its utilization and efficiency.

Emergence in Technical Systems (Emergenz in technischen Systemen)

Summury This article briefly reviews systems, which show self-organizational behavior and defines emergence as their central property. Then it tries to contrast emergent behavior, which is a bottom-up process, with the classical top-down design process. In the last section the paper discusses the Observer/Controller concept as a possible solution to this apparent contradiction.

The establishment and reasoning of knowledge base system for mechanism kinematic schemes

As one of the key problems of computer-aided conceptual design (CACD) for mechanism kinematic schemes, the effective establishment and management of knowledge base systems of kinematic behaviours and mechanisms is still troubled by information redundancy and unreasonable structure at present. Retrieval efficiency and solving intelligence of knowledge base reasoning systems on the basis of the knowledge classification method mentioned above have many unsatisfactory factors. So in this paper, firstly, data standardization technology and combined classification methods have been applied to carry out the classification of kinematic behaviours and mechanisms in the mapping field between the kinematic behaviour level and the mechanism level of conceptual design. Also, the principle of computer coding and storing have been built to give a fast and broad selection of mechanisms that meets the requirements of basic motion characters. Then on the basis of what was mentioned above, the heuristic matching propagation principle (HMPP) of kinematic behaviours and its truth table serve as a guide to perform mechanism type selections. The knowledge base automatic reasoning system of mechanism kinematic schemes based on HMPP is developed. By means of depth first search strategy, the motion requirements are matched against objects in the knowledge base along the orientation of function unit-mechanism ID→function unit ID→kinematic behaviour ID(output/input)→motion type coding/ continuity coding/linearity coding/directionality coding at four different levels of abstraction. Top-down design process in this paper conforms to the law of innovative thinking for designers. If a direct match in a higher level was not discovered, then the design course will be transformed into the match at a low level automatically. According to the truth table of HMPP, once non-zero elements in kinematic behaviour ID (“1” or “2”) appear in the matching process, they will propagate until the solving process is over, and become one of the coding of the feasible solutions. The heuristic nature of HMPP presents a top-down solving method to decompose the complex requirements into several simpler ones. Different from traditional solving methods, the method presented in our research work has two advantages. Firstly it is easier to be operated and realized with a computer. Secondly, it is a creative process by nature. Finally, an application is given to indicate its practicability and effectiveness.