Nicola Senin

Integrated Design in a Service Marketplace

This paper presents a service marketplace vision for enterprise-wide integrated design modeling. In this environment, expert participants and product development organizations are empowered to publish their geometric design, CAE, manufacturing, or marketing capabilities as live services that are operable over the Internet. These services are made available through a service marketplace. Product developers, small or large, can subscribe to and flexibly inter-relate these services to embody a distributed product development organization, while simultaneously creating system models that allow the prediction and analysis of integrated product performance. It is hypothesized that product development services will become commodities, much like many component-level products are today. It will be possible to rapidly interchange equivalent design service providers so that the development of the product and the definition of the product development organization become part of the same process. Computer-aided design tools will evolve to facilitate the publishing of live design services. A research prototype system called DOME is used to illustrate the concept and a pilot study with Ford Motor Company is used in a preliminary assessment of the vision.

Distributed Object-Based Modeling in Design Simulation Marketplace

Predictive integrated system modeling is now a pressing issue in the design of complex products ranging from home air conditioners to automobiles and aircraft. While product development organizations have official top-down development processes, it is generally understood that in practice individual participants perform their work in an informal marketplace, bartering service exchange relationships to get what they need to resolve their part of the problem. The authors envision a distributed simulation service marketplace running in parallel with the activities of design participants. This paper develops an object model representation to enable this vision for a decentralized design simulation marketplace. A prototype implementation, called DOME (Distributed Object-based Modeling Environment), is used to illustrate the concept on a beverage container design problem.

Concurrent assembly planning with genetic algorithms

Abstract This work investigates the application of genetic algorithm (GA)-based search techniques to concurrent assembly planning , where product design and assembly process planning are performed in parallel, and the evaluation of a design configuration is influenced by the performance of its related assembly process. Several types of GAs and an exhaustive combinatorial approach are compared, in terms of reliability and speed in locating the global optimum. The different algorithms are tested first on a set of artificially generated assembly planning problems, which are intended to represent a broad spectrum of combinatorial complexity; then an industrial case study is presented. Test problems indicate that GAs are slightly less reliable than the combinatorial approach in finding the global, but are capable of identifying solutions which are very close to the global optimum with consistency, soon outperforming the combinatorial approach in terms of execution times, as the problem complexity grows. For an industrial case study of low combinatorial complexity, such as the one chosen in this work, GAs and combinatorial approach perform almost equivalently, both in terms of reliability and speed. In summary, GAs seem a suitable choice for those planning applications where response time is an important factor, and results which are close enough to the global optimum are still considered acceptable such as in concurrent assembly planning, where response time is a key factor when assessing the validity of a product design configuration in terms of the performance of its assembly plan.

Combined inkjet printing and infrared sintering of silver nanoparticles using a swathe-by-swathe and layer-by-layer approach for 3-dimensional structures

Despite the advancement of additive manufacturing (AM)/3-dimensional (3D) printing, single-step fabrication of multifunctional parts using AM is limited. With the view of enabling multifunctional AM (MFAM), in this study, sintering of metal nanoparticles was performed to obtain conductivity for continuous line inkjet printing of electronics. This was achieved using a bespoke three-dimensional (3D) inkjet-printing machine, JETx, capable of printing a range of materials and utilizing different post processing procedures to print multilayered 3D structures in a single manufacturing step. Multiple layers of silver were printed from an ink containing silver nanoparticles (AgNPs) and infrared sintered using a swathe-by-swathe (SS) and layer-by-layer sintering (LS) regime. The differences in the heat profile for the SS and LS was observed to influence the coalescence of the AgNPs. Void percentage of both SS and LS samples was higher toward the top layer than the bottom layer due to relatively less IR exposure in the top than the bottom. The results depicted a homogeneous microstructure for LS of AgNPs and showed less deformation compared to the SS. Electrical resistivity of the LS tracks (13.6 ± 1 μΩ cm) was lower than the SS tracks (22.5 ± 1 μΩ cm). This study recommends the use of LS method to sinter the AgNPs to obtain a conductive track in 25% less time than SS method for MFAM.

Regulation of Anopheles gambiae male accessory gland genes influences postmating response in female

In Drosophila, the accessory gland proteins (Acps) secreted from the male accessory glands (MAGs) and transferred along with sperm into the female reproductive tract have been implicated in triggering postmating behavioral changes, including refractoriness to subsequent mating and propensity to egg laying. Recently, Acps have been found also in Anopheles, suggesting similar functions. Understanding the mechanisms underlying transcriptional regulation of Acps and their functional role in modulating Anopheles postmating behavior may lead to the identification of novel vector control strategies to reduce mosquito populations. We identified heat‐shock factor (HSF) binding sites within the Acp promoters of male Anopheles gambiae and discovered three distinct Hsf isoforms; one being significantly up‐regulated in the MAGs after mating. Through genome‐wide transcription analysis of Hsf‐silenced males, we observed significant down‐regulation in 50% of the Acp genes if compared to control males treated with a construct directed against an unrelated bacterial sequence. Treated males retained normal life span and reproductive behavior compared to control males. However, mated wild‐type females showed a ~46% reduction of egg deposition rate and a ~23% reduction of hatching rate (~58% combined reduction of progeny). Our results highlight an unsuspected role of HSF in regulating Acp transcription in A. gambiae and provide evidence that Acp down‐regulation in males leads a significant reduction of progeny, thus opening new avenues toward the development of novel vector control strategies.—Dottorini, T., Persampieri, T., Palladino, P., Baker, D. A., Spaccapelo, R., Senin, N., Crisanti, A. Regulation of Anopheles gambiae male accessory gland genes influences postmating response in female. FASEB J. 27, 86–97 (2013). www.fasebj.org

Morphologic segmentation algorithms for extracting individual surface features from areal surface topography maps

Areal segmentation, i.e. the partitioning of areal surface topography data into regions, has recently attracted significant research interest in surface metrology. In particular morphologic segmentation, i.e. partitioning into Maxwellian hills and dales—currently the only segmentation approach endorsed by ISO specification standards—has shown potential for capturing the salient traits of a surface, so that its surface texture can be better encoded by parameters. However, recent developments in dimensional metrology applied to structured surfaces with features of dimensions on the order of micrometres (micro-electromechanical system, microfluidics, etc), and many other studies aimed at characterizing individual features in unstructured surfaces (scratches, bumps, holes, etc), are showing the importance of segmentation for extracting localized features from areal data. In this work, morphologic segmentation is applied to a selected set of case studies of industrial relevance, involving structured, semi-structured and unstructured surfaces, where the main goal is not the assessment of surface texture, but the extraction of individual surface features. The examples are designed to provide an overview of the main advantages and issues when applying morphologic segmentation in a comprehensive set of application scenarios.

Dimensional metrology of micro parts by optical three-dimensional profilometry and areal surface topography analysis

A novel approach is proposed for the characterization of critical dimensions and geometric errors, suitable for application to micro-fabricated parts and devices characterized as step-like structured surfaces. The approach is based on acquiring areal maps with a high-precision optical three-dimensional profilometer and on processing topography data with novel techniques obtained by merging knowledge and algorithms from surface metrology, dimensional metrology and computer vision/image processing. Thin-foil laser targets for ion acceleration experiments are selected as the test subject. The main issues related to general applicability and metrological performance of the methodology are identified and discussed.

Serum IgE Reactivity Profiling in an Asthma Affected Cohort

Background Epidemiological evidence indicates that atopic asthma correlates with high serum IgE levels though the contribution of allergen specific IgE to the pathogenesis and the severity of the disease is still unclear. Methods We developed a microarray immunoassay containing 103 allergens to study the IgE reactivity profiles of 485 asthmatic and 342 non-asthmatic individuals belonging to families whose members have a documented history of asthma and atopy. We employed k-means clustering, to investigate whether a particular IgE reactivity profile correlated with asthma and other atopic conditions such as rhinitis, conjunctivitis and eczema. Results Both case-control and parent-to-siblings analyses demonstrated that while the presence of specific IgE against individual allergens correlated poorly with pathological conditions, particular reactivity profiles were significantly associated with asthma (p<10E-09). An artificial neural network (ANN)-based algorithm, calibrated with the profile reactivity data, correctly classified as asthmatic or non-asthmatic 78% of the individual examined. Multivariate statistical analysis demonstrated that the familiar relationships of the study population did not affect the observed correlations. Conclusions These findings indicate that asthma is a higher-order phenomenon related to patterns of IgE reactivity rather than to single antibody reactions. This notion sheds new light on the pathogenesis of the disease and can be readily employed to distinguish asthmatic and non-asthmatic individuals on the basis of their serum reactivity profile.

On the application of coloured Petri nets to computer aided assembly planning

The problem of assembly process planning is particularly critical for the automation and integration of production, due to the combinatorial complexity and the requirement of both flexibility and productivity. Several planning methodologies and techniques have been proposed in the literature, using an approach limited to specific product typologies and structures. Some of them are more suitable for dedicated automated assembly and assembly lines than for flexible automated assembly and flexible assembly systems (FAS) and assembly job shops. Due to the time-based competition, both cycle time reduction and task parallelism increase require a technique suitable to the generation of assembly plans with flexibility, efficiency and parallelism. The paper presents and discusses the application of coloured Petri nets (CPN) and timed coloured Petri nets (TCPN) to the computer aided assembly planning (CAAP) problem, both to online and off-line planning, and presents a prototype CAAP architecture, that is implemented and validated by means of the assembly planning of an industrial product.<<ETX>>

On the characterisation of periodic patterns in tessellated surfaces

Tessellated surfaces are a class of structured surfaces where texture has been engineered to reproduce a periodic pattern, specifically designed to meet a functional requirement. Despite having gained considerable acceptance in industrial production, tessellated surfaces still pose considerable challenges in terms of their metrological verification. The small scale of the dominant texture features requires the application of instruments typical of surface metrology; however, the computation of conventional surface texture parameters generally is not sufficient to capture the geometric properties and regularity aspects, which are fundamental for a complete characterisation of the pattern. In the work reported here, the characterisation of a periodic texture pattern is approached as a dimensional metrology problem, where the aim is the determination of target dimensional and geometric properties directly mapped to the design specifications. To illustrate the approach presented in this paper a specific test case, involving laser textured dimpled patterns designed to reduce friction in bearing applications, has been selected. This test case is used to highlight the many issues and critical aspects involved in the characterisation of tessellated surfaces.