Evolutionary truss topology optimization using a graph-based parameterization concept

A novel parameterization concept for the optimization of truss structures by means of evolutionary algorithms is presented. The main idea is to represent truss structures as mathematical graphs and directly apply genetic operators, i.e., mutation and crossover, on them. For this purpose, new genetic graph operators are introduced, which are combined with graph algorithms, e.g., Cuthill-McKee reordering, to raise their efficiency. This parameterization concept allows for the concurrent optimization of topology, geometry, and sizing of the truss structures. Furthermore, it is absolutely independent from any kind of ground structure normally reducing the number of possible topologies and sometimes preventing innovative design solutions. A further advantage of this parameterization concept compared to traditional encoding of evolutionary algorithms is the possibility of handling individuals of variable size. Finally, the effectiveness of the concept is demonstrated by examining three numerical example

Development of CFRP racing motorcycle rims using a heuristic evolutionary algorithm approach

The scope of this paper is the application of evolutionary optimization methods to the development of composite fibre reinforced plastics (CFRP) racing motorcycle rims. The mass and the moment of inertia of a front and a rear CFRP rim are minimized subject to manufacturing, strength, and stiffness constraints. The stacking sequence of the composite laminates is optimized by applying a sophisticated parameterization concept making an excellent compromise between a huge variety of structure properties and a reasonable number of optimization parameters. The mechanical properties are simulated using the finite element analysis package ANSYS . Resulting displacement and Tsai-Wu index values are combined with the mass of the rim in order to assign a fitness value to each different design solution. The smart formulation of the fitness function allows the exploration of solutions close to the required strength and stiffness properties. The proprietary software DynOPS is utilized as an optimization engine. It links an evolutionary algorithm to arbitrary simulation programs and controls the entire optimization process. The sophisticated parameterization concept, together with the fitness function formulation, are the basis for the development of CFRP motorcycle rims decisively lighter than state-of-the-art magnesium alloy rim

A graph-based parameterization concept for global laminate optimization

A new graph-based parameterization concept aimed at the global optimization of laminated structures by the means of evolutionary algorithms and finite element analysis is introduced. The motivation to develop this novel parameterization concept is twofold. First, the entire design space is accessible to optimi zation down to the smallest entity, which is a single finite element, and secondly, this concept guarantees greatest flexibility in terms of laminate layer shape and placement. The finite element mesh of a structure is represented as a mathematical graph. Substructures of this graph form fiber reinforced and possibly overlapping patches and are affiliated to virtual graph vertices representing their properties. Adapted genetic variation operators are directly applied on this graph. The method allows for concurrent optimization of number, size, shape, and position of the patches and an arbitrary number of material related properties for each of them. The novel concept overcomes the limits of traditional geometry-based approaches, as it is able to represent almost arbitrary patch shapes even on curved surfaces. Two numerical examples demonstrate the efficiency of the metho

Complex-shaped beam element and graph-based optimization of compliant mechanisms

Compliant mechanisms are designed to be intentionally flexible, providing hingeless mechanisms. This work contributes a complex-shaped beam element formulation in conjunction with the ground structure approach. We identify compliant mechanism design solutions by using evolutionary topology optimization and increase flexibility by using a parametrization concept based on graph theory. The new operators for evolutionary optimization are also explained and sample problems are used to address the question of how our contribution increases design solutions spac

Binding between the neural cell adhesion molecules axonin-1 and Nr- CAM/Bravo is involved in neuron-glia interaction

Neural cell adhesion molecules of the immunoglobulin superfamily mediate cellular interactions via homophilic binding to identical molecules and heterophilic binding to other family members or structurally unrelated cell-surface glycoproteins. Here we report on an interaction between axonin-1 and Nr-CAM/Bravo. In search for novel ligands of axonin-1, fluorescent polystyrene microspheres conjugated with axonin-1 were found to bind to peripheral glial cells from dorsal root ganglia. By antibody blockage experiments an axonin-1 receptor on the glial cells was identified as Nr-CAM. The specificity of the interaction was confirmed with binding studies using purified axonin-1 and Nr-CAM. In cultures of dissociated dorsal root ganglia antibodies against axonin-1 and Nr-CAM perturbed the formation of contacts between neurites and peripheral glial cells. Together, these results implicate a binding between axonin-1 of the neuritic and Nr-CAM of the glial cell membrane in the early phase of axon ensheathment in the peripheral nervous system

Action contribution to competence judgments: the use of the journey schema

The current research considered the question of how performing an action, or merely preparing the body for action, can have an impact on social judgments related to person perception. Participants were asked to ascribe competence and warmth characteristics to a target person by reading a metaphoric text while their body was manipulated to be prepared for the processing of action-congruent information. In Experiment 1, participants whose forward body action matched the metaphoric action described in the text ascribed more competence characteristics to a politician than did control participants. In Experiment 2, participants whose body was merely prepared for forward movement also ascribed more competence characteristics to a politician than did control participants. In addition, the data from Experiment 2 ruled out an alternative non-embodied explanation (i.e., that effect is due to basic associative processes) grounded in the existing literatures on attitudes by demonstrating that body manipulation had no effect on competence when a non-metaphoric text was used. Finally, no evidence was found that body manipulation affects warmth judgments. These studies converge in demonstrating that forward body movements enhance the favorability of competence judgments when these match the metaphoric forward movements described by text.info:eu-repo/semantics/publishedVersio

Ratings of Overall Olfactory Function

The aim of this study was to investigate the accuracy of self-reported ratings of olfactory function in 83 healthy subjects. Such ratings were compared with quantitative measures of olfactory function, as well as with ratings of nasal patency. In experiment 1 subjects rated olfactory function and nasal patency before olfactory testing, whereas in experiment 2 the reverse was the case. No feedback regarding test results were provided until after completion of the testing. The principal findings were: (i) when ratings preceded measurements of olfactory function, there was no significant correlation between the two parameters. However, ratings of olfactory function correlated significantly with ratings of nasal airway patency. (ii) In contrast, when measurements of olfactory function preceded the ratings, this constellation switched. Now ratings of olfactory function correlated significantly with measured olfactory function, whereas there was no significant correlation between ratings of nasal airway patency and ratings of olfactory function. In conclusion, these data suggest that ratings of olfactory function are unreliable in healthy, untrained subjects. The ratings seem to reflect changes of nasal airway patency to a larger degree than measurable olfactory function. The results further indicate that this is mainly due to the limited attention the sense of smell receives in daily lif

Potential pitfalls in the accuracy of analysis of natural sense-antisense RNA pairs by reverse transcription-PCR

<p>Abstract</p> <p>Background</p> <p>The ability to accurately measure patterns of gene expression is essential in studying gene function. The reverse transcription polymerase chain reaction (RT-PCR) has become the method of choice for the detection and measurement of RNA expression patterns in both cells and small quantities of tissue. Our previous results show that there is a significant production of primer-independent cDNA synthesis using a popular RNase H^-RT enzyme. A PCR product was amplified from RT reactions that were carried out without addition of RT-primer. This finding jeopardizes the accuracy of RT-PCR when analyzing RNA that is expressed in both orientations. Current literature findings suggest that naturally occurring antisense expression is widespread in the mammalian transcriptome and consists of both coding and non-coding regulatory RNA. The primary purpose of this present study was to investigate the occurrence of primer-independent cDNA synthesis and how it may influence the accuracy of detection of sense-antisense RNA pairs.</p> <p>Results</p> <p>Our findings on cellular RNA and <it>in vitro </it>synthesized RNA suggest that these products are likely the results of RNA self-priming to generate random cDNA products, which contributes to the loss of strand specificity. The use of RNase H⁺RT enzyme and carrying the RT reaction at high temperature (50°C) greatly improved the strand specificity of the RT-PCR detection.</p> <p>Conclusion</p> <p>While RT PCR is a basic method used for the detection and quantification of RNA expression in cells, primer-independent cDNA synthesis can interfere with RT specificity, and may lead to misinterpretation of the results, especially when both sense and antisense RNA are expressed. For accurate interpretation of the results, it is essential to carry out the appropriate negative controls.</p