A functional approach to redesign

This paper describes a methodology to assist in the identification of possible conceptual design variants during redesign. The approach is based on functional reasoning and involves: (1) the structural and functional analysis of an existing design; (2) the production of abstract representations of functions and design entities using conceptual graphs; and (3) design interrogation based on a functional tree approach. The research reported in this paper also focuses on the definition and the representation of elementary mechanical functions. Extended Backus-Naur Form (EBNF) notations are used to structure in a computable form, the relevant information (or design knowledge) conceptualised in either the conceptual graphs or the functional trees. EBNF syntax is also used to formulate rules which aid the partial automation of the reasoning process. The EBNF notations can be mapped to any programming language. A diaphragm valve is used as a case study to demonstrate the approach.     

Improving the robustness of fractional polynomial models by preliminary covariate transformation: A pragmatic approach

Fractional polynomials have been found useful in univariate and multivariable non-linear regression analysis. As with many flexible regression models, they may be prone to distortion of the fitted function caused by values with high leverage at either extreme of the covariate distribution. Furthermore, fractional polynomial functions are not invariant to a change of origin of the covariate. A new approach, based on a preliminary, almost-linear transformation of a covariate, is proposed. The transformation is approximately linear within the bulk of the observations and tapers smoothly to a truncation of the extremes. It incorporates a predefined shift of the origin away from zero. Empirical studies show that this transformation is effective in reducing extreme leverages. In two real datasets, it is shown its use can result in more sensible final models.     

A multi-point reduced-order modeling approach of transient structural dynamics with application to robust design optimization

Predicting the transient response of structures by high-fidelity simulation models within design optimization and uncertainty quantification often leads to unacceptable computational cost. This paper presents a reduced-order modeling (ROM) framework for approximating the transient response of linear elastic structures over a range of design and random parameters. The full-order response is projected onto a lower-dimensional basis spanned by modes computed from a proper orthogonal decomposition (POD) of full-order model simulation results at multiple calibration points. The basis is further enriched by gradients of the POD modes with respect to the design/random parameters. A truncation strategy is proposed to compensate for the increase in basis vectors due to the proposed enrichment strategies. The accuracy, efficiency and robustness of the proposed framework are studied with a two-dimensional model problem. The numerical results suggest that the proposed ROM approach is well suited for large parameter changes and that the number of basis vectors needs to be increased only linearly with the number of design and random parameters to maintain a particular ROM performance. The application of the proposed ROM approach to robust shape optimization demonstrates significant savings in computational cost over using full-order models. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.     

Shape mining: A holistic data mining approach for engineering design

Although the integration of engineering data within the framework of product data management systems has been successful in the recent years, the holistic analysis (from a systems engineering perspective) of multi-disciplinary data or data based on different representations and tools is still not realized in practice. At the same time, the application of advanced data mining techniques to complete designs is very promising and bears a high potential for synergy between different teams in the development process. In this paper, we propose shape mining as a framework to combine and analyze data from engineering design across different tools and disciplines. In the first part of the paper, we introduce unstructured surface meshes as meta-design representations that enable us to apply sensitivity analysis, design concept retrieval and learning as well as methods for interaction analysis to heterogeneous engineering design data. We propose a new measure of relevance to evaluate the utility of a design concept. In the second part of the paper, we apply the formal methods to passenger car design. We combine data from different representations, design tools and methods for a holistic analysis of the resulting shapes. We visualize sensitivities and sensitive cluster centers (after feature reduction) on the car shape. Furthermore, we are able to identify conceptual design rules using tree induction and to create interaction graphs that illustrate the interrelation between spatially decoupled surface areas. Shape data mining in this paper is studied for a multi-criteria aerodynamic problem, i.e. drag force and rear lift, however, the extension to quality criteria from different disciplines is straightforward as long as the meta-design representation is still applicable.     

A SfM-based 3D face reconstruction method robust to self-occlusion by using a shape conversion matrix

This paper presents a 3D face reconstruction method using multiple 2D face images. Structure from motion (SfM) methods, which have been widely used to reconstruct 3D faces, are vulnerable to point correspondence errors caused by self-occlusion. In order to solve this problem, we propose a shape conversion matrix (SCM) which estimates the ground-truth 2D facial feature points (FFPs) from the observed 2D FFPs corrupted by self-occlusion errors. To make the SCM, the training observed 2D FFPs and ground-truth 2D FFPs are collected by using 3D face scans. An observed shape model and a ground-truth shape model are then built to represent the observed 2D FFPs and the ground-truth 2D FFPs, respectively. Finally, the observed shape model parameter is converted to the ground truth shape model parameter via the SCM. By using the SCM, the true locations of the self-occluded FFPs are estimated exactly with simple matrix multiplications. As a result, SfM-based 3D face reconstruction methods combined with the proposed SCM become more robust against point correspondence errors caused by self-occlusion, and the computational cost is significantly reduced. In experiments, the reconstructed 3D facial shape is quantitatively compared with the 3D facial shape obtained from a 3D scanner, and the results show that SfM-based 3D face reconstruction methods with the proposed SCM show a higher accuracy and a faster processing time than SfM-based 3D face reconstruction methods without the SCM.     

Multiversion object constellations: A new approach to support a designer's database work

The logical organization of database support for CAD applications is considered, which has to account for specific requirements including versioning, consistency and design transactions. A new approach to the organization, manipulation and management of design objects in a design database is described, which is based on the notion of an objectconstellation. A constellation is a set of multiversion objects together with all their subobjects. Constellations can be versioned intoconfigurations, which comprise one version of each object of the underlying constellation. We argue that constellations are adequate units of allocation to individual designers, while configurations form appropriate units of consistency. We show how the constellation approach renders a flexible support of hierarchically organized, cooperative design processes possible, by employing specific transactions whose scope is limited to well-defined portions of a database. Most importantly, the approach provides new insight into the consistency problem for design databases, by providing an adequate approach to multilevel consistency, and by making consistency of a design context-dependent.     

A new hesitant fuzzy QFD approach: An application to computer workstation selection

Computer workstation selection is a multiple criteria decision making problem that is generally based on vague linguistic assessments, which represent human judgments and their hesitancy. In this paper, a new fuzzy quality function deployment (QFD) approach is used to effectively determine the design requirements (DRs) of a computer workstation. Hesitant fuzzy linguistic term sets (HFLTS) are innovatively employed to capture the hesitancy of the experts in this approach. More precisely, the proposed new QFD approach is the first study that determines the importance of customer requirements (CRs), the relations between CRs and DRs and the correlations among DRs via HFLTS. Additionally, HFLTS based Analytic Hierarchy Process (AHP) and Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) methods are utilized in the computational steps to select the best computer workstation. A real industrial application is carried out to validate the implementation of the proposed approach.     

A critical narrative approach to openness: The impact of open development on structural transformation

Openness has become an important, all‐encompassing term denoting activities facilitated by sharing, using, producing, and redistributing information and communication resources within digital information systems. We compare theoretical advancements that emphasize processes and characteristics of openness with the limitations of extant approaches that have largely focused on improvements to productivity and efficiency. Based on Foucault and Bruner's ideas, this paper contributes a new critical narrative approach to understanding openness explicitly focused on structural transformation and power. The analysis focuses on the case of open development, examining 20 key studies based primarily on developing countries. The critical narrative approach unpacked the production of power/knowledge across actors, intentions, and outcomes of openness research and practice. We find that discursive formations are reliant on technocentric and normative ideals of researchers, leading to narratives of hypothetical outcomes that exclude marginalized perspectives. We propose hermeneutic composability and contesting normative narratives of openness as analytical techniques for an integrated, mutually constitutive conception of interactions between individuals, open artefacts, and open social praxis.     

Adaptive neural control of high-order uncertain nonaffine systems: A transformation to affine systems approach

This brief investigates the adaptive neural network (NN) control of a class of high-order nonaffine nonlinear systems with completely unknown dynamics. Since the control terms appear within the unknown nonlinearity, traditional control schemes and stability analysis are usually rendered extremely complicated. Our main contribution includes a novel system transformation that converts the nonaffine system into an affine system through a combination of a low-pass filter and state transformation. As a result, the state-feedback control of the nonaffine system can be viewed as the output-feedback control of an affine system in normal form. The transformed system becomes linear with respect to the new input while the traditional backstepping approach is not needed thus allowing the synthesis to be extremely simplified. It is theoretically proven that all the signals in the closed-loop system are uniformly ultimately bounded (UUB). Simulation results are provided to demonstrate the performance of the developed controller.     

SCOlog: A logic-based approach to analysing supply chain operation dynamics

In a complex business world, characterised by globalisation and rapid rhythms of change, understanding supply chain (SC) operation dynamics is crucial. This paper describes a logic-based approach to analysing SC operation dynamics, named SCOlog. SC operation is modelled in a declarative fashion and it is simulated following rule-based execution semantics. This approach facilitates the automated explanation of simulated SC operational behaviours and performance. The automated explanation support provided by SCOlog is found to improve the understanding of the domain for non-SCM experts. Furthermore, SCOlog allows for maintainability and reusability.     

Developing a seabed resurvey strategy: A GIS approach to modelling seabed changes and resurvey risk

There has been a steady transition towards the representation, analysis and modelling of dynamic spatio-temporal relationships in geographical information systems (GISs). These developments open up opportunities for investigating and modelling the dynamic relationships that occur in the coastal and marine environments and how these relate to human activities. Such a spatio-temporal approach is applied in this research to address an issue faced by the bodies responsible for maintaining navigation safety in territorial waters and this paper introduces the developed resurvey decision support system. The developed system models morphological change in response to hydrodynamic conditions and determines the seabed locations that require resurvey based on the modelled change and navigation characteristics. System validation tests indicate that the morphological modelling tool is under-predicting the magnitude and lateral extent of the change which then influences the locations that require resurvey. Additional sensitivity tests of the morphological modelling parameters highlight the influence of the parameters on the outputs and derived predictions. The achieved modelling results and resurvey decision indicate the applicability of utilising a GIS to model seabed change as an input into decision support systems for planning and management purposes. The results also suggest the applicability of the modelling and decision support methodology to similar problems in the coastal and marine environments.     

Dragons, bats and evil knights: A three-layer design approach to character-based creative play

Creative play requires a fertile but well-defined design space. This paper describes a design process for creating three-dimensional virtual reality play spaces that allow the development and exploration of social interactions and relationships. The process was developed as part of a commercial research effort to create an interactive virtual reality entertainment system that allows children to engage in creative and constructive play within an established action/adventure framework. The effort centres on designing Al characters for aconstructive narrative. We claim that a behaviour-based architecture is an ideal starting point for developing agents for such a process, but that its full realization requires additional architectural structures and methodological support for the design process. In this paper, we describe a character architecture called Spark of Life (SoL). We also propose a three-layer design process for producing fertile and aesthetic constructive narratives. Finally, we describe our experience in implementing these ideals in an industrial setting.     

A multidimensional approach to determinants of computer use in primary education: teacher and school characteristics

The central aim of this study was to test a model that integrates determinants of educational computer use. In particular, the article examines teacher and school characteristics that are associated with different types of computer use by primary school teachers. A survey was set up, involving 527 teachers from 68 primary schools in Flanders. A separate questionnaire was administered to information and communication technology (ICT) coordinators from the same schools to gather additional information about cultural and contextual school characteristics. The combined impact of both teacher and school characteristics was explored through a multilevel analysis. Besides the importance of school characteristics, the results reveal differential effects of specific characteristics on specific types of computer use. Cultural school characteristics for instance, such as the schools’ openness to change and the availability of an ICT school policy plan, are positively related to the use of computers as a learning tool and to the adoption of ICT in view of basic computer skills. In contrast, no cultural school characteristic seem to be associated with the use of computers as an information tool. In a comparable way, teacher characteristics are associated with specific types of computer use, e.g. the variable gender. In general, male teachers report integrating computers more often. In this study, it appears that gender differences only exist in relation to the adoption of computers as an information tool. The results demonstrate that a multidimensional approach provides more insight into the characteristics affecting computer use.     

A detection problem: Sensitivity and uncertainty analysis of a land surface temperature approach to detecting dynamics of water use by groundwater-dependent vegetation

Sustainable management of groundwater-dependent vegetation (GDV) requires the accurate identification of GDVs, characterisation of their water use dynamics and an understanding of associated errors. This paper presents sensitivity and uncertainty analyses of one GDV mapping method which uses temperature differences between time-series of modelled and observed land surface temperature (LST) to detect groundwater use by vegetation in a subtropical woodland. Uncertainty in modelled LST was quantified using the Jacobian method with error variances obtained from literature. Groundwater use was inferred where modelled and observed LST were significantly different using a Student's t-test. Modelled LST was most sensitive to low-range wind speeds (<1.5 m s⁻¹), low-range vegetation height (<=0.5 m), and low-range leaf area index (<=0.5 m² m⁻²), limiting the detectability of groundwater use by vegetation under such conditions. The model-data approach was well-suited to detection of GDV because model-data errors were lowest for climatic conditions conducive to groundwater use.     

A functional approach to the stability of non-linear systems by use of the comparison theorem†

The paper presents some stability conditions for non-linear systems based on the application of the comparison theorem. The non-linear integral equation which gives the output of the system is dominated by another non-linear integral equation of simpler structure. The study of the boundedness of this equation is carried out by considering an algebraic equation; the stability conditions for the non-linear system corresponds to the existence of real positive roots of the algebraic equation.     

A coordinate transformation approach for efficient repeated solution of Helmholtz equation pertaining to obstacle scattering by shape deformations

A computational model is developed for efficient solutions of electromagnetic scattering from obstacles having random surface deformations or irregularities (such as roughness or randomly-positioned bump on the surface), by combining the Monte Carlo method with the principles of transformation electromagnetics in the context of finite element method. In conventional implementation of the Monte Carlo technique in such problems, a set of random rough surfaces is defined from a given probability distribution; a mesh is generated anew for each surface realization; and the problem is solved for each surface. Hence, this repeated mesh generation process places a heavy burden on CPU time. In the proposed approach, a single mesh is created assuming smooth surface, and a transformation medium is designed on the smooth surface of the object. Constitutive parameters of the medium are obtained by the coordinate transformation technique combined with the form-invariance property of Maxwell’s equations. At each surface realization, only the material parameters are modified according to the geometry of the deformed surface, thereby avoiding repeated mesh generation process. In this way, a simple, single and uniform mesh is employed; and CPU time is reduced to a great extent. The technique is demonstrated via various finite element simulations for the solution of two-dimensional, Helmholtz-type and transverse magnetic scattering problems.     

Adapting grazing practices to limit the reforestation of mountainous summer pastures: A process-based approach

European mountain landscapes are experiencing massive land-use changes and high rates of natural reforestation since the 1950s. Summer pastures are particularly sensitive to those dynamics since their natural state depends on human activities. A process-based model - SHIELD (Simulating Herd Impact on Encroachment in upLanD) – has been developed to identify the key leverages of pastoral practices to limit the natural reforestation in the Haut-Vicdessos (Pyrenees Mountains, France). Simulations are compared to observed land cover changes to validate the model's structure. Scenarios are simulated to assess various grazing practices on reforestation dynamics: a baseline scenario and three scenarios with contrasted pastoral management: (i) reintroducing herds with no human supervision, (ii) reintroducing herds supervised by a shepherd and (iii) increasing the cattle load without supervision. Results show that supervising the intensity of land units' occupancy can be as efficient as increasing the cattle load to limit the ongoing trends of reforestation.     

Robot acceptance model for care (RAM-care): A principled approach to the intention to use care robots

Robots are emerging in welfare services, and organizations require information on whether novel technologies are approved among staff. On the basis of technology acceptance theories, this study proposes a model that adds a principled approach to the intention to use care robots. Data of 544 professionals with care robot experience were collected. The use intention was predicted by usefulness, enjoyment, social influence, and attitude. Respondents who found robots useful and accepted by their colleagues were more likely to view robot use as consistent with their personal values. The care robot acceptance model supports consideration of the profession-specific context in robotization.