Showing papers on "Iterative design published in 2012"

Aerodynamic Shape Optimization of a Vertical-Axis Wind Turbine Using Differential Evolution

Abstract: The purpose of this study is to introduce and demonstrate a fully automated process for optimizing the airfoil cross-section of a vertical-axis wind turbine (VAWT). The objective is to maximize the torque while enforcing typical wind turbine design constraints such as tip speed ratio, solidity, and blade profile. By fixing the tip speed ratio of the wind turbine, there exists an airfoil cross-section and solidity for which the torque can be maximized, requiring the development of an iterative design system. The design system required to maximize torque incorporates rapid geometry generation and automated hybrid mesh generation tools with viscous, unsteady computational fluid dynamics (CFD) simulation software. The flexibility and automation of the modular design and simulation system allows for it to easily be coupled with a parallel differential evolution algorithm used to obtain an optimized blade design that maximizes the efficiency of the wind turbine.

Iterative plug-and-play methodology for constructing and modifying synthetic gene networks

Abstract: We present a methodology for the design, construction and modification of synthetic gene networks. This method emphasizes post-assembly modification of constructs based on network behavior, thus facilitating iterative design strategies and rapid tuning and repurposing of gene networks. The ease of post-construction modification afforded by this approach and the ever-increasing repository of components within the framework will help accelerate the development of functional genetic circuits for synthetic biology.

Supporting product architecture design using computational design synthesis with network structure constraints

Abstract: A product’s architecture can affect many aspects of product and process quality, from technical performance to the design effort required, production costs and satisfaction of later lifecycle requirements. This paper explores how computational tools can augment creative methods in product architecture design. Based on an empirical study aiming to understand the context of product architecture design, a new computational method is proposed to support this activity. In the method, product architectures—networks of components linked by connections—can be synthesised using constraints on the structure of the network to define the set of ‘realisable’ architectures for a product. An example illustrates how the method might be used on a real design problem, including the construction of an appropriate set of network structure constraints and the identification of promising architectures from the synthesis results. Preliminary evaluation of the method’s usability, assessed through a laboratory experiment, and its utility, assessed through application to a real historical design problem, supported by initial validation by an engineer from the case study company, suggests that the method has value for engineering design practice.

The design of AC permanent magnet motors for electric vehicles: a computationally efficient model of the operational envelope

Abstract: Salient brushless AC (BLAC) permanent magnet (PM) motors are a preferred topology in the rapidly growing area of electric vehicle traction due to their inherent high efficiencies and excellent power densities. In the design of these systems it is important to appraise the motor performance across the entire torque-speed envelope. This paper presents computationally efficient techniques that allow rapid and accurate modelling of the entire operational envelope of any BLAC PM motor, enabling the generation of torque/speed characteristics and loss maps that can be used in an iterative design process. The proposed techniques are validated against test data from an in-house 35kW interior PM motor design and a comparison between a measured and computed efficiency map for the 2004 Toyota Prius motor is undertaken.

User-Centered Design: Why and How to Put Users First in Software Development

Abstract: In this chapter we provide an overview of the activities and artefacts of the usercentered design (UCD) methodology – a successful and practical approach to the design of software user interfaces. After tracing its foundational principles (early focus on users, empirical measurement using prototypes and iterative design) back to 1985s seminal paper by Gould and Lewis, we will highlight each of five central categories of design activities (Scope, Analyse, Design, Validate and Deliver) performed in UCD. Potential integration of UCD into two popular categorizations of software development (User Interface First vs. User Interface Later) will be explored and then demonstrated in a real life case study from the field of electronic engineering along with a practical takeaway regarding the relationship of UCD and eLearning.

Direct and inverse iterative design method for centrifugal pump impellers

Abstract: A combined direct and inverse iterative design method was developed for the hydraulic design of centrifugal pump impellers. This method is based on the fluid continuity and motion equations and solves for the meridional velocity taking into account the effects of the blade shape on the flow. The blade shape is drawn by point-by-point integration with blade thickening and smoothing using conformal mapping. Two examples designed using the direct and inverse iterative design method are compared to results using the traditional design method with significantly different meridional velocity distributions and three-dimensional blade shapes. Numerical simulations and tests show that the highest pump efficiency is 2.2% higher with this design method than with the traditional design method. The numerical results agree well with the experiments with a smoother flow pattern than with the traditional design, especially in the volute.

Output Information Based Iterative Learning Control Law Design With Experimental Verification

Abstract: This paper considers iterative learning control law design using the theory of linear repetitive processes. This setting enables trial-to-trial error convergence and along-the-trial performance to be considered simultaneously in the design. It is also shown that this design extends naturally to include robustness to unmodeled plant dynamics. The results from experimental application of these laws to a gantry robot performing a pick and place operation are given, together with a discussion of the positioning of this approach relative to alternatives and possible further research.

Design optioneering: multi-disciplinary design optimization through parameterization, domain integration and automation of a genetic algorithm

Abstract: The overall performance of buildings is heavily impacted by design decisions made during the early stages of the design process. Design professionals are most often unable to explore design alternatives and their impact on energy profiles adequately during this phase. Combining parametric modeling with multi-disciplinary design optimization has been previously identified as a potential solution. By utilizing parametric design and multi-disciplinary design optimization to influence design at the schematic level in the interest of exploring more energy efficient design configurations, the H. D. S. Beagle 1.0 tool was developed. The tool enables the generation of design alternatives according to user defined parameter ranges; automatically gathers the energy analysis result of each design alternative; automatically calculates three objective functions; and uses Genetic Algorithm to intelligently search, rank, select, and breed the solution space for decision making. Current case studies demonstrate our tool's ability to reduce design cycle latency and improve quality. However, the future work is needed to further investigate how to acclimate this process to accommodate early design stages and processes.

Design space pruning through hybrid analysis in system-level design space exploration

Abstract: System-level design space exploration (DSE), which is performed early in the design process, is of eminent importance to the design of complex multi-processor embedded system architectures. During system-level DSE, system parameters like, e.g., the number and type of processors, the type and size of memories, or the mapping of application tasks to architectural resources, are considered. Simulation-based DSE, in which different design instances are evaluated using system-level simulations, typically are computationally costly. Even using high-level simulations and efficient exploration algorithms, the simulation time to evaluate design points forms a real bottleneck in such DSE. Therefore, the vast design space that needs to be searched requires effective design space pruning techniques. This paper presents a technique to reduce the number of simulations needed during system-level DSE. More specifically, we propose an iterative design space pruning methodology based on static throughput analysis of different application mappings. By interleaving these analytical throughput estimations with simulations, our hybrid approach can significantly reduce the number of simulations that are needed during the process of DSE.

Advanced engineering design : an integrated approach

Abstract: The design process Information, entropy, and its relationship to design Axiomatic design Metric design Reliability-based design Reliability-based design Entropy based design.

Design for Research Results: Experimental Prototyping and Play Testing

Abstract: In this article, the authors examine iterative design methods for experimental game prototype development. They recognize the area of game design as a wicked problem space, that is, an area where attempts at producing solutions change the understanding of the problems. They argue that it is vital in game-design research to build and test designs in order to explore how certain game mechanics can result in different play dynamics and play experiences. Depending on the scope of research questions and available resources, it is important to carefully plan the design process of prototypes, their development, and the testing of them. It is also important to consider what types of data to obtain, and how to treat the data, in order to acquire materials for analysis that can support the exploration of the research questions of a study. The purpose of this article is to provide a navigation aid through this process. Various methods of prototyping and types of prototypes are described, along with considerations regarding the type of game that is developed. Then, various types of play tests are presented along with recommendations, depending on timing within the production cycle and availability of test-players. Also, an overview of potential methods of obtaining data from play tests is provided.

A product module identification approach based on axiomatic design and design structure matrix

Abstract: In terms of creating customized products rapidly, modularity is deemed to be an effective developmental strategy for handling product variety and intricacy. In order to develop reasonable modular p...

Looking ahead: how field trials can work in iterative and exploratory design of ubicomp systems

Abstract: We investigate in which forms field trials are a workable model as part of an exploratory design process for sporadic, mobile, non-work settings A major concern of evaluating ubicomp systems is to study how practices and context of use emerge and develop over time when new technology is introduced To introduce a sophisticated version of our own prototype in the course of an iterative design process, we conducted a public field trial of the system---a new platform for mobile democratic discussions in municipal planning---that we distributed via the Android Market However, it turned out to be surprisingly difficult to evaluate our design in a setting that stretches over time, place, and without a preselected set of users Analyzing our difficulties, we develop a general model for methods studying ubicomp systems On the basis of this model, we characterize an openly interactive approach to field trials in order to look ahead rather than back

A superelement formulation for the efficient layout design of complex multi-component system

Abstract: In view of the prohibited computing time and the complexity of design procedure, a superelement formulation (SEF) is proposed to deal with the simultaneous optimization of component placement and the framework topology. In the iterative design process, each component is modelled as a movable superelement so that the sensitivity analysis with respect to the location design variables can be largely simplified by the SEF. Moreover, based on the Kuhn---Tucker optimality condition, two decomposition strategies are developed as variant approaches for the simultaneous design of multi-component system. By means of numerical examples, these approaches are compared to show their capability and efficiency for the system compliance minimization.

Cognitive load theory in e-learning

Abstract: Cognitive load can be assessed and monitored using a multitude of subjective (self-reports, i.e. Hart & Staveland, 1988; Paas, 1992) and more objective methods (dual tasks, eye-tracking, heart-rate measurements, skin conductance measurements, cf. Brunken, Plass, & Leutner, 2003; Beatty, 1982, Paas, van Merrienboer, & Adam, 1994), either during the learning or afterwards, so that instruction can be optimized based on mental effort data using iterative design (a cyclic process of prototyping, testing, analyzing, and refining a product or process, ultimately improving the quality and functionality of the design). Computer simulations provide an excellent environment to apply CLT principles. However, such e-environments are technically complex and therefore add to extraneous load. Separating the technical knowledge of how to use the computer interface from the actual conceptual knowledge using sequencing should reduce this load to a reasonable extent (cf. Clarke, Ayres & Sweller, 2006). The authors provide guidelines on how to use CLT in the design of e-environments and discuss what future directions can be taken to further optimize the design of such environments.

A hybrid computer-aided linkage design system for tracing open and closed planar curves

Abstract: This paper presents a computer-aided linkage design system for tracing prescribed open or closed planar curves. The mechanism design is considered a mixture of science and art. The former is about utilizing computers to rigorously size a mechanism in meeting a set of design requirements and the latter is about taking advantage of designers' experience to narrow down the design domain and speed up the design process. The ultimate goal of the presented design system is to incorporate both science and art into the linkage design process by (1) developing an automatic design framework that is based on library searching and optimization techniques and (2) developing an interactive design framework that is based on advanced human-computer interfaces. To enable the design automation framework, we first pre-built a library of open and closed planar curves generated by commonly used planar linkages. We then turned the classical linkage path generation problem into a library searching problem together with a local optimization problem. To enable the interactive design framework, we developed a set of design interfaces that facilitate designers to intervene and steer the design process. This hybrid design system was developed based on our existing VRMDS (Virtual Reality Mechanism Design Studio) framework. To demonstrate its functionalities, we provided four representative design cases of 4-bar and crank-slider linkages. The result shows that the system returned a desired solution in seconds. We also demonstrate the extensibility of the system by implementing designs of planar 4-bar and crank-slider linkages.

A development process for usable large scale interactive critical systems: application to satellite ground segments

Abstract: While a significant effort is being undertaken by the Human-Computer Interaction community in order to extend current knowledge about how users interact with computing devices and how to design and evaluate new interaction techniques, very little has been done to improve the reliability of software offering such interaction techniques. However, malfunctions and failures occur in interactive systems leading to incidents or accidents that, in aviation for instance, are [22] 80% of the time attributed to human error demonstrating the inadequacy between the system and its operators. As an error may have a huge impact on human life, strong requirements are usually set both on the final system and on the development process itself. Interactive safety-critical systems have to be designed taking into account on an equal basis several properties including usability, reliability and operability while their associated design process is required to handle issues such as scalability, verification, testing and traceability. However, software development solutions in the area of critical systems are not adequate leading to defects especially when the interactive aspects are considered. Additionally, the training program development is always designed independently from the system development leading to operators trained with inadequate material. In this paper we propose a new iterative design process embedding multiple design and modeling techniques (both formal and informal) advocated by HCI and dependable computing domains. These techniques have been adapted and tuned for interactive systems and are used in a synergistic way in order to support the integration of factors such as usability, dependability and operability and at the same time in order to deal with scalability, verification and traceability.

Impacts of concurrency, iteration, design review, and problem complexity on design project lead time and error generation

Abstract: A case study of an aircraft engine manufacturer is used to analyze the effects of management levers on the lead time and design errors generated in an iteration-intensive concurrent engineering process. The levers considered are amount of design-space exploration iteration, degree of process concurrency, and timing of design reviews. Simulation is used to show how the ideal combination of these levers can vary with changes in design problem complexity, which can increase, for instance, when novel technology is incorporated in a design. Results confirm that it is important to consider multiple iteration-influencing factors and their interdependencies to understand concurrent processes, because the factors can interact with confounding effects. The article also demonstrates a new approach to derive a system dynamics model from a process task network. The new approach could be applied to analyze other concurrent engineering scenarios.

A knowledge acquisition method to model parametric engineering design processes

Abstract: This paper proposes an interview-style method to create models of engineering design processes intended for design automation. Development of design automation tools often requires a model of the design artefact, design process or design knowledge. However, the knowledge about product development often resides tacitly inside the mind of designers and is difficult to make explicit. The lack of explicit process models creates a challenge for organisations to improve their design processes. A method is proposed to create explicit models of tacit design knowledge of structured design problems. A standardised model of the design process is used to classify sets of information and processes. The content of the model is filled step-by-step through a series of questions. A prescriptive modelling method reduces the required effort for knowledge modelling and allows design processes to be supported more effectively. The method is demonstrated for a design case with tacit knowledge and a further nine cases are used to demonstrate scalability and comparison between design knowledge of mechanical components and complex product systems.

Design Strategy and Software Design Effectiveness

Abstract: Software design is about a sequence of steps taken to achieve a goal. Designers must plan their approach to carrying out these steps. In studying designers at work, the authors observed breadth- versus depth-first approaches to design-space exploration and problem- versus solution-driven approaches during the actual design. Which approaches and when to use them are important to effective design. The authors suggest four archetypical strategies that designers can choose under different circumstances, thus making design strategy one of the early design decisions.

Iterative Design of Concentration Factors for Jump Detection

Abstract: The concentration method of edge detection was developed to compute the locations and values of jump discontinuities in a piecewise-analytic function from its first few Fourier series coefficients. The accuracy and characteristic features of the resulting jump approximation depend on Fourier space "filter" factors known as concentration factors. In this paper, we provide a flexible, iterative framework for the design of these factors. Previously devised concentration factors are shown to be the solutions of specific problem formulations within this new framework. We also provide sample formulations of the procedure applicable to the design of concentration factors for data with missing spectral bands. Several illustrative examples are used to demonstrate the capabilities of the method.

New Approach to Product Platform Design Based on Axiomatic Design and Design Relationship Matrix

Abstract: Product platform is the core of product family,and establishing reasonably the product platform is crucial to increase product design adaptability.Axiomatic design is utilized as framework,and a design method for product platform is put forward based on functional requirements analysis.Considering the link between customer needs and product quality characteristics,product functional requirements are classified into basic functional requirements,expectable functional requirements and adjunctive functional requirements based on Kano model,and their concepts are defined.The functional requirements are zigzagging mapping to design parameters,and the design matrix is created.The design relationship matrix of the product is built by analyzing the fluency relationship between functional requirement and design parameter,and the extension clustering algorithm is utilized to cluster the elements in design relationship matrix.The module realizing basic functional requirements of product family is defined as common module.Based on above foundations,the platform parameters are selected by analyzing the sensitivity of the design parameters,and the clustering algorithm is applied to determine the sharing strategy of platform parameters.This method of product platform design is validated by a case study of electro-hydraulic dram brake design.

Systemic Operational Design (Sod): Gaining and Maintaining the Cognitive Initiative

Abstract: : The purpose of this monograph is to demonstrate that Systemic Operational Design (SOD) is a more adaptive approach to designing military operations at the joint operational level than the Military Decision-Making Process (MDMP), the Joint Operation Planning and Execution System (JOPES), and Effects-Based Operations (EBO) Systemic Operational Design gains and maintains the cognitive initiative by enabling the operational commander to recognize and exploit emerging opportunities through its unique process of iterative design This monograph began as an investigation to determine if either Effects-Based Operations or Systemic Operational Design should replace the traditional Military Decision-Making Process It soon became clear that these approaches do not accomplish the same functions, are not applicable at the same levels, and are not mutually exclusive The Military Decision-Making Process originated as a tactical decision-making process, and it remains the most appropriate of the three approaches at that level It deals with the physical threat on the ground with a decisiveness enabled by an organization of hierarchical authority Effects-Based Operations is suitable only at the operational level It takes the time to model the threat as a holistic system and contemplates the desired behavior changes various actions on that system would produce It exceeds the physical realm of the tactical and explicitly translates strategic directives into tactical effects Systemic Operational Design is a holistic approach that introduces the discrete element of design to inform planning It is abstract and conceptual It creates a cognitive map and continually updates it by the learning that occurs through action Fusing Systemic Operational Design with the Military Decision-Making Process might be the best way ahead for operational planning and design

Robust, flexible and operational mine design strategies

Abstract: Strategic planning in mining is an important value accretive process One of the most essential aspects during the planning phase is determining the correct system design A traditional mine design process develops a fixed system for one set of conditions or expected values An alternative is to develop a robust system that deals with variation, by handling a range of conditions within the optimisation process Conversely, a flexible design can be generated which changes the system dynamically over time in response to change It is hypothesised that a flexible design generates more value than a robust design which in turn generates more value than a traditional design However, due to constant change, a fully flexible design is not practical Ideally, a hybrid of the two methods would be optimal An operational design is proposed as a manual solution to this problem This paper compares these different new design methodologies