Data trend mining for predictive systems design

The goal of this research is to propose a data mining based design framework that can be used to solve complex systems design problems in a timely and efficient manner, with the main focus being product family design problems. Traditional data acquisition techniques that have been employed in the product design community have relied primarily on customer survey data or focus group feedback as a means of integrating customer preference information into the product design process. The reliance of direct customer interaction can be costly and time consuming and may therefore limit the overall size and complexity of the customer preference data. Furthermore, since survey data typically represents stated customer preferences (customer responses for hypothetical product designs, rather than actual product purchasing decisions made), design engineers may not know the true customer preferences for specific product attributes, a challenge that could ultimately result in misguided product designs. By analyzing large scale time series consumer data, new products can be designed that anticipate emerging product preference trends in the market space. The proposed data trend mining algorithm will enable design engineers to determine how to characterize attributes based on their relevance to the overall product design. A cell phone case study is used to demonstrate product design problems involving new product concept generation and an aerodynamic particle separator case study is presented for product design problems requiring attribute relevance characterization and product family clustering. Finally, it is shown that the proposed trend mining methodology can be expanded beyond product design problems to include systems of systems design problems such as military systems simulations

Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Impacts of sociopolitical conditions

Space development scenarios and the choice of technologies to carry them out depend upon the future social, economic, and political factors. A brief discussion concerning the impact of sociopolitical conditions on space exploration is presented. Some of the topics mentioned include: space weapons/warfare, international cooperation, NASA's Search for Extraterrestrial Intelligence (SETI) Program, and superpower rivelry

Fog_Hive© : 3D fog collection along the coastal Atacama desert

The provision of drinking water turns out to be one of the great challenges for the future because central water supply systems cannot technically or logistically be implemented. FogHive©'s main aim is stopping desertification by repairing endangered fog oases ecosystems, and harvesting water for drinking and irrigation and fostering potential inhabitation in many arid coasts such as Chile, Peru and others latitudes. FogHive© is resilient to different climatic contexts and can dynamically response to the different and intermittent prevailing wind directions by keeping the screen ratio of 1:1 or 1:2. It is an adaptable and lightweight design with emphasis in optimal frame types, forms, structural and surface sizes, structural and constructional specifications made with aluminium, galvanised steel or timber. FogHive© employs hydrophobic meshes and a deployable space-frame to intersect atmospheric water and then harvest it for drinking and irrigation. FogHive© has been tested throughout climatic simulations in the fog oasis of Alto Patache, Atacama Desert (2010). It also performs like a shading/cooling device and a soil humidifier for greenery or crop. Being a transformable construction, it can easily be transported and installed. Its footprint is hexagonal (6m side) which is resistant against strong winds and ‘aerodynamic’ to the landscape. FogHive© consists of a water-repellent skin facing prevailing winds and a shading device facing the Equator. The water collector, filtering and irrigation network considers local structural materials and techniques. Regarding conventional two-dimensional fog collection, FogHive© upgrades the following aspects: 1. Increasing rate and yield of advection fog by taking into account harvesting rate and climatic parameters; 2. Structural reinforcement of fog collectors through lightweight and deployable space-frames; 3. Reducing installation and maintenance of fog collection; 4. Lowering physical impacts on surrounding

Multi-objective optimization of a wing fence on an unmanned aerial vehicle using surrogate-derived gradients

In this paper, the multi-objective, multifidelity optimization of a wing fence on an unmanned aerial vehicle (UAV) near stall is presented. The UAV under consideration is characterized by a blended wing body (BWB), which increases its efficiency, and a tailless design, which leads to a swept wing to ensure longitudinal static stability. The consequence is a possible appearance of a nose-up moment, loss of lift initiating at the tips, and reduced controllability during landing, commonly referred to as tip stall. A possible solution to counter this phenomenon is wing fences: planes placed on top of the wing aligned with the flow and developed from the idea of stopping the transverse component of the boundary layer flow. These are optimized to obtain the design that would fence off the appearance of a pitch-up moment at high angles of attack, without a significant loss of lift and controllability. This brings forth a constrained multi-objective optimization problem. The evaluations are performed through unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations. However, since controllability cannot be directly assessed through computational fluid dynamics (CFD), surrogate-derived gradients are used. An efficient global optimization framework is developed employing surrogate modeling, namely regressive co-Kriging, updated using a multi-objective formulation of the expected improvement. The result is a wing fence design that extends the flight envelope of the aircraft, obtained with a feasible computational budget

Insight into High-quality Aerodynamic Design Spaces through Multi-objective Optimization

An approach to support the computational aerodynamic design process is presented and demonstrated through the application of a novel multi-objective variant of the Tabu Search optimization algorithm for continuous problems to the aerodynamic design optimization of turbomachinery blades. The aim is to improve the performance of a specific stage and ultimately of the whole engine. The integrated system developed for this purpose is described. This combines the optimizer with an existing geometry parameterization scheme and a well- established CFD package. The system’s performance is illustrated through case studies – one two-dimensional, one three-dimensional – in which flow characteristics important to the overall performance of turbomachinery blades are optimized. By showing the designer the trade-off surfaces between the competing objectives, this approach provides considerable insight into the design space under consideration and presents the designer with a range of different Pareto-optimal designs for further consideration. Special emphasis is given to the dimensionality in objective function space of the optimization problem, which seeks designs that perform well for a range of flow performance metrics. The resulting compressor blades achieve their high performance by exploiting complicated physical mechanisms successfully identified through the design process. The system can readily be run on parallel computers, substantially reducing wall-clock run times – a significant benefit when tackling computationally demanding design problems. Overall optimal performance is offered by compromise designs on the Pareto trade-off surface revealed through a true multi-objective design optimization test case. Bearing in mind the continuing rapid advances in computing power and the benefits discussed, this approach brings the adoption of such techniques in real-world engineering design practice a ste