178,587 research outputs found
Design: One, but in different forms
This overview paper defends an augmented cognitively oriented generic-design
hypothesis: there are both significant similarities between the design
activities implemented in different situations and crucial differences between
these and other cognitive activities; yet, characteristics of a design
situation (related to the design process, the designers, and the artefact)
introduce specificities in the corresponding cognitive activities and
structures that are used, and in the resulting designs. We thus augment the
classical generic-design hypothesis with that of different forms of designing.
We review the data available in the cognitive design research literature and
propose a series of candidates underlying such forms of design, outlining a
number of directions requiring further elaboration
Effects of Steel and Polypropylene Fiber Addition on Interface Bond Strength between Normal Concrete Substrate andSelf-Compacting Concrete Topping
Based on facts that the composite action in semi-precast and strengthened structural system depends on the bond
strength of the interface between concrete faces of different ages, this preliminary research is aimed to investigate effects of mixed polypropylene (PPF) and steel fiber (SF) addition on the hardened properties of Self-Compacting Concrete (SCC) and its bond strength when used as topping layer on normal concrete substrate. Effects of hybrid fiber addition on the hardened properties of SCC were investigated based on the compressive, splitting tensile and flexural strength of concrete specimens which is tested in 28 days of age. In the next step, the tensile and shear strength of the interface were evaluated using indirect splitting tensile and bi-surface shear test method. In this research, fiber addition were prepared using 1 kg/m PPF and various SF addition ranging from 15 kg/m3, 20 kg/m3, 25 kg/m3 and 30 kg/m3. Test results indicate that hybrid fiber addition does not affect the compressive strength significantly but it leads ositive improvement to the splitting tensile and flexural strength of hardened SCC and also improve the bond strength between SCC and normal concrete. Hybrid fiber addition of 1 kg/m3 PPF which is combined with 20 kg/m3 SF can be suggested as optimum composition for Hybrid Fiber Reinforced Self-Compacting Concrete (HyFRSCC) that will be used as topping or overlay material based on its hardened properties and interface strength
Incommensurability and rationality in engineering design: the case of functional decomposition
In engineering design research different models of functional decomposition are advanced side-by-side. In this paper I explain and validate this co-existence of models in terms of the Kuhnian thesis of methodological incommensurability. I advance this analysis in terms of the thesis’ construal of (non-algorithmic) theory choice in terms of values, expanding this notion to the engineering domain. I further argue that the (by some) implicated threat of the thesis to rational theory choice has no force in the functional decomposition case: co-existence of different models of functional decomposition is rational from an instrumental point of view. My explanation covers cases in which different models are advanced as means for the same objective. Such cases cannot be explicated with the explanatory construct of variety in objectives, as advanced in other analyses of co-existing conceptualizations in engineering
Optimizing Bone Scaffold Porosity Distributions
We consider a simple one-dimensional time-dependent model for bone
regeneration in the presence of a bio-resorbable polymer scaffold. Within the
framework of the model, we optimize the effective mechanical stiffness of the
polymer scaffold together with the regenerated bone matrix. The result of the
optimization procedure is a scaffold porosity distribution which maximizes the
stiffness of the scaffold-bone system over the regeneration time, such that the
propensity for mechanical failure is reduced
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Automated Design of Tissue Engineering Scaffolds by Advanced CAD
The design of scaffolds with an intricate and controlled internal structure represents a
challenge for Tissue Engineering. Several scaffold manufacturing techniques allow the
creation of complex and random architectures, but have little or no control over geometrical
parameters such as pore size, shape and interconnectivity- things that are essential for tissue
regeneration. The combined use of CAD software and layer manufacturing techniques allow
a high degree of control over those parameters, resulting in reproducible geometrical
architectures. However, the design of the complex and intricate network of channels that are
required in conventional CAD, is extremely time consuming: manually setting thousands of
different geometrical parameters may require several days in which to design the individual
scaffold structures. This research proposes an automated design methodology in order to
overcome those limitations. The combined use of Object Oriented Programming and
advanced CAD software, allows the rapid generation of thousands of different geometrical
elements. Each has a different set of parameters that can be changed by the software, either
randomly or according to a given mathematical formula, so that they match the different
distribution of geometrical elements such as pore size and pore interconnectivity.
This work describes a methodology that has been used to design five cubic scaffolds with
pore size ranging from about 200 to 800 µm, each with an increased complexity of the
internal geometry.Mechanical Engineerin
Optimizing Engagement Simulations Through the Advanced Framework for Simulation, Integration, and Modeling (AFSIM) Software
The ability to effectively model and simulate military missions holds the potential to save lives, money, and resources for the United States. The Advanced Framework for Simulation, Integration, and Modeling (AFSIM) software is a tool used to rapidly simulate and model new technologies and mission level scenarios. In this thesis, our objective is to integrate a closed loop optimization routine with AFSIM to identify an effective objective function to assess optimal inputs for engagement scenarios. Given the many factors which impact a mission level engagement, we developed a tool which interfaces with AFSIM to observe the effects from multiple inputs in an engagement scenario. Our tool operates under the assumption that simulation results have met an acceptable convergence threshold. The objective function evaluates the effectiveness and associated cost with a scenario using a genetic algorithm and a particle swarm optimization algorithm. From this, a statistical analysis was performed to assess risk from the distribution of effectiveness and cost at each point. The method allows an optimal set of inputs to be selected for a desired result from the selected engagement scenario.No embargoAcademic Major: Mechanical Engineerin
Modeling the Structure and Complexity of Engineering Routine Design Problems
This paper proposes a model to structure routine design problems as well as a model of its design complexity. The idea is that having a proper model of the structure of such problems enables understanding its complexity, and likewise, a proper understanding of its complexity enables the development of systematic approaches to solve them. The end goal is to develop computer systems capable of taking over routine design tasks based on generic and systematic solving approaches. It is proposed to structure routine design in three main states: problem class, problem instance, and problem solution. Design complexity is related to the degree of uncertainty in knowing how to move a design problem from one state to another. Axiomatic Design Theory is used as reference for understanding complexity in routine design
Development of a mechatronic sorting system for removing contaminants from wool
Automated visual inspection (AVI) systems have been
extended to many fields, such as agriculture and the food, plastic
and textile industries. Generally, most visual systems only inspect
product defects, and then analyze and grade them due to the lack
of any sorting function. This main reason rests with the difficulty of
using the image data in real time. However, it is increasingly important
to either sort good products from bad or grade products into
separate groups usingAVI systems. This article describes the development
of a mechatronic sorting system and its integration with a
vision system for automatically removing contaminants from wool
in real time. The integration is implemented by a personal computer,
which continuously processes live images under the Windows
2000 operating system. The developed real-time sorting approach
is also applicable to many other AVI systems
Teaching Software Engineering through Robotics
This paper presents a newly-developed robotics programming course and reports
the initial results of software engineering education in robotics context.
Robotics programming, as a multidisciplinary course, puts equal emphasis on
software engineering and robotics. It teaches students proper software
engineering -- in particular, modularity and documentation -- by having them
implement four core robotics algorithms for an educational robot. To evaluate
the effect of software engineering education in robotics context, we analyze
pre- and post-class survey data and the four assignments our students completed
for the course. The analysis suggests that the students acquired an
understanding of software engineering techniques and principles
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