The Application of Polynomial Response Surface and Polynomial Chaos Expansion Metamodels within an Augmented Reality Conceptual Design Environment

The engineering design process consists of many stages. In the conceptual phase, potential designs are generated and evaluated without considering specifics. Winning concepts then advance to the detail design and high fidelity simulation stages. At this point in the process, very accurate representations are made for each design and are then subjected to rigorous analysis. With the advancement of computer technology, these last two phases have been very well served by the software community. Engineering software such as computer-aided design (CAD), finite element analysis (FEA), and computational fluid dynamics (CFD) have become an inseparable part of the design process for many engineered products and processes. Conceptual design tools, on the other hand, have not undergone this type of advancement, where much of the work is still done with little to no digital technology. Detail oriented tools require a significant amount of time and training to use effectively. This investment is considered worthwhile when high fidelity models are needed. However, conceptual design has no need for this level of detail. Instead, rapid concept generation and evaluation are the primary goals. Considering the lack of adequate tools to suit these needs, new software was created. This thesis discusses the development of that conceptual design application. Traditional design tools rely on a two dimensional mouse to perform three dimensional actions. While many designers have become familiar with this approach, it is not intuitive to an inexperienced user. In order to enhance the usability of the developed application, a new interaction method was applied. Augmented reality (AR) is a developing research area that combines virtual elements with the real world. This capability was used to create a three dimensional interface for the engineering design application. Using specially tracked interface objects, the user\u27s hands become the primary method of interaction. Within this AR environment, users are able perform many of the basic actions available within a CAD system such as object manipulation, editing, and assembly. The same design environment also provides real time assessment data. Calculations for center of gravity and wheel loading can be done with the click of a few buttons. Results are displayed to the user in the AR scene. In order to support the quantitative analysis tools necessary for conceptual design, additional research was done in the area of metamodeling. Metamodels are capable of providing approximations for more complex analyses. In the case of the wheel loading calculation, the approximation takes the place of a time consuming FEA simulation. Two different metamodeling techniques were studied in this thesis: polynomial response surface (PRS) and polynomial chaos expansion (PCE). While only the wheel loading case study was included in the developed application, an additional design problem was analyzed to assess the capabilities of both methods for conceptual design. In the second study, the maximum stresses and displacements within the support frame of a bucket truck were modeled. The source data for building the approximations was generated via an FEA simulation of digital mockups, since no legacy data was available. With this information, experimental models were constructed by varying several factors, including: the distribution of source and test data, the number of input trials, the inclusion of interaction effects, and the addition of third order terms. Comparisons were also drawn between the two metamodeling techniques. For the wheel loading models, third order models with interaction effects provided a good fit of the data (root mean square error of less than 10%) with as few as thirty input data points. With minimal source data, however, second order models and those without interaction effects outperformed third order counterparts. The PRS and PCE methods performed almost equivalently with sufficient source data. Difference began to appear at the twenty trial case. PRS was more suited to wider distributions of data. The PCE technique better handled smaller distributions and extrapolation to larger test data. The support frame problem represented a more difficult analysis with non-linear responses. While initial third order results from the PCE models were better than those for PRS, both had significantly higher error than in the previous case study. However, with simpler second order models and sufficient input data (more than thirty trials) adequate approximation results were achieved. The less complex responses had error around 10%, and the model predictions for the non-linear response were reduced to around 20%. These results demonstrate that useful approximations can be constructed from minimal data. Such models, despite the uncertainty involved, will be able to provide designers with helpful information at the conceptual stage of a design process

Fixing Food : The Mediterranean Region

This report investigates food sustainability issues in the Mediterranean in the context of the various social, economic and environmental challenges confronting the region. As a framework, it uses the three pillars—sustainable agriculture, nutritional challenges, and food loss and waste—of the Food Sustainability Index (FSI), developed by The Economist Intelligence Unit with the Barilla Center for Food & Nutrition Foundation (BCFN). Refer to their earlier report, Fixing Food: towards a more sustainable food system, for a detailed explanation of the index and its composition.Its french version is also available online

The Swiss library context between innovation and tradition: the Swiss National Library and the Münstergasse Library of Bern

Nel giugno 2018 gli studenti del Master di II livello in Archivistica, Biblioteconomia e Codicologia dell’Università degli Studi di Firenze hanno compiuto un viaggio studio in Svizzera con l’obiettivo di conoscere ed entrare in contatto con il contesto bibliotecario svizzero.L’articolo descrive la Biblioteca Nazionale Svizzera, la sua organizzazione, la sua storia, i suoi servizi e i progetti nei quali è coinvolta all’interno della Confederazione svizzera (E-helveticat, l’Archivio svizzero di letteratura, la Bibliografia della Storia svizzera) e a livello internazionale (come il GND). Per concludere, l’articolo descrive la biblioteca Münstergasse di Berna, con la sua biblioteca universitaria e cantonale, conosciuta a livello internazionale per i progetti relativi agli incunaboli.In June 2018, students of the “Master di 2° livello” (Second Level Master Courses, accessible only to students that have a Second Cycle Degree or equivalent) in Archives, Library Science and Codicology of University of Florence made a study-trip to Switzerland and came into contact with the Swiss library world.This article describes the Swiss National Library, its organization, history, services and projects in which it is involved into Swiss Confederation (i.e. E-helveticat, The Swiss Literary Archives, Bibliography on Swiss History) and internationally (such as the GND). Finally, the article describes the Münstergasse Library of Bern, that is a University and cantonal library, known internationally for its projects with incunabula

DU Undergraduate Showcase: Research, Scholarship, and Creative Works

DU Undergraduate Showcase: Research, Scholarship, and Creative Work

THE SPERMATHECA OF EURYCEA BISLINEATA

Volume: 49Start Page: 250End Page: 26

The Application of Polynomial Response Surface and Polynomial Chaos Expansion Metamodels within an Augmented Reality Conceptual Design Environment

The engineering design process consists of many stages. In the conceptual phase, potential designs are generated and evaluated without considering specifics. Winning concepts then advance to the detail design and high fidelity simulation stages. At this point in the process, very accurate representations are made for each design and are then subjected to rigorous analysis. With the advancement of computer technology, these last two phases have been very well served by the software community. Engineering software such as computer-aided design (CAD), finite element analysis (FEA), and computational fluid dynamics (CFD) have become an inseparable part of the design process for many engineered products and processes. Conceptual design tools, on the other hand, have not undergone this type of advancement, where much of the work is still done with little to no digital technology. Detail oriented tools require a significant amount of time and training to use effectively. This investment is considered worthwhile when high fidelity models are needed. However, conceptual design has no need for this level of detail. Instead, rapid concept generation and evaluation are the primary goals. Considering the lack of adequate tools to suit these needs, new software was created. This thesis discusses the development of that conceptual design application. Traditional design tools rely on a two dimensional mouse to perform three dimensional actions. While many designers have become familiar with this approach, it is not intuitive to an inexperienced user. In order to enhance the usability of the developed application, a new interaction method was applied. Augmented reality (AR) is a developing research area that combines virtual elements with the real world. This capability was used to create a three dimensional interface for the engineering design application. Using specially tracked interface objects, the user's hands become the primary method of interaction. Within this AR environment, users are able perform many of the basic actions available within a CAD system such as object manipulation, editing, and assembly. The same design environment also provides real time assessment data. Calculations for center of gravity and wheel loading can be done with the click of a few buttons. Results are displayed to the user in the AR scene. In order to support the quantitative analysis tools necessary for conceptual design, additional research was done in the area of metamodeling. Metamodels are capable of providing approximations for more complex analyses. In the case of the wheel loading calculation, the approximation takes the place of a time consuming FEA simulation. Two different metamodeling techniques were studied in this thesis: polynomial response surface (PRS) and polynomial chaos expansion (PCE). While only the wheel loading case study was included in the developed application, an additional design problem was analyzed to assess the capabilities of both methods for conceptual design. In the second study, the maximum stresses and displacements within the support frame of a bucket truck were modeled. The source data for building the approximations was generated via an FEA simulation of digital mockups, since no legacy data was available. With this information, experimental models were constructed by varying several factors, including: the distribution of source and test data, the number of input trials, the inclusion of interaction effects, and the addition of third order terms. Comparisons were also drawn between the two metamodeling techniques. For the wheel loading models, third order models with interaction effects provided a good fit of the data (root mean square error of less than 10%) with as few as thirty input data points. With minimal source data, however, second order models and those without interaction effects outperformed third order counterparts. The PRS and PCE methods performed almost equivalently with sufficient source data. Difference began to appear at the twenty trial case. PRS was more suited to wider distributions of data. The PCE technique better handled smaller distributions and extrapolation to larger test data. The support frame problem represented a more difficult analysis with non-linear responses. While initial third order results from the PCE models were better than those for PRS, both had significantly higher error than in the previous case study. However, with simpler second order models and sufficient input data (more than thirty trials) adequate approximation results were achieved. The less complex responses had error around 10%, and the model predictions for the non-linear response were reduced to around 20%. These results demonstrate that useful approximations can be constructed from minimal data. Such models, despite the uncertainty involved, will be able to provide designers with helpful information at the conceptual stage of a design process.</p

Response of the meadow vole, Microtus pennsylvanicus, to prescribed burning in a tallgrass prairie

Bibliography: pages [70]-74.This study was initiated with attention to the following questions: 1) What are the direct effects of fire on the resident populations of the meadow vole, Microtus pennsylvanicus inhabiting a tallgrass prairie restoration? 2) What aspects of the plant and surrounding vole communities may be important in the recolonization of burned habitat by pennsylvanicus? and 3) What characterizes recolonizing M^_ pennsylvanicus individuals as compared to animals persisting in the unburned areas? Population density as well as age structure, trappability, survival rate, sex ratio, male body weight and home range size were monitored by monthly/bimonthly trapping from April 1980 until October 1981 on a 1.6 ha grid which was divided into 0.72 ha treatment and control plots. When applicable, demographic characteristics were analysed using non-parametric tests due to differences in sample sizes. Plant community characteristics, above-ground biomass and percent cover were also observed using clip quadrats and point-contact sampling. Thirty samples were removed from each area at regular intervals from March to October. The results indicated that fire did not appear to harm the voles directly. Small mammal remains were not found after the burn and several voles were later caught on the control plot. Other species of small mammals returned to the burn plot within two weeks of the fire. Microtus pennsylvanicus entered the burn plot well before minimal levels of cover became established. Population density in the control plot had been increasing steadily and it appeared the voles colonized the burn plot in response to increased population density. Individuals colonizing the burn plot could be characterized as predominantly young adult males and non-reproducing females. Thus, fire seems to have only a transitory effect on vole populations, and recolonization patterns reflect demographic events as well as vegetation characteristics.M.S. (Master of Science

An applied floristic study of endangered and threatened vascular plant species occurring on selected public land in DeKalb and Ogle Counties, Illinois

Includes bibliographical references.Includes maps.The Illinois list of endangered and threatened vascular plant species identifies 315 species of plants as being in danger of extermination from Illinois. An inventory of specimens of endangered and threatened species housed in the herbarium of Northern Illinois University was conducted and 30 specimens of 22 endangered species and 9 specimens of 7 threatened species were found housed therein. A list was compiled, based on habitat and distribution information, of endangered and threatened plant species with possible occurrence in the study areas. The study areas were surveyed for habitat types present and categorized according to species likely to occur there. An inventory was conducted of Illinois endangered and threatened vascular plant species on selected public lands in DeKalb and Ogle Counties, Illinois. One endangered species, Rusty Woodsia (Woodsia ilvensis) and one threatened species, Ginseng (Panax quinquefolius) were found to occur in the study areas.M.S. (Master of Science

Three-dimensional deformation of the Achilles tendon insertion in mice - The entheseal fibrocartilage as a water cushion

The insertion of the Achilles tendon to the Calcaneus transmits forces between soft and hard tissue. From an adaptionist perspective, the insertional tissues are expected to distribute stress homogeneously, in spite of the abrupt change in tissue elastic behavior. But it remains yet unclear, whether and how they achieve those properties. The collagen fibers follow approximately straight courses along the tendon. Before they insert, the fibers curve over the posterior Calcaneus surface while passing through an unmineralized fibrocartilage. According to their curvature, they can exert pressure on the extrafibrillar matrix which is rich in water. Therefore the fibrocartilage is expected to lose volume under pressure. We compared the deformation of the proximal tendon and the distal fibrocartilage within three-dimensional images of relaxed and loaded Achilles tendon insertions from mice [Mus musculus, strain C57BL/6J, n = 3], acquired using synchrotron radiation-based micro-computed tomography with propagation-based phase-contrast. Forces were measured during the entire period of the experiment.The tomographic images are the first to render the three-dimensional deformation of intact tendon insertions. The permanent stretch of the experiment leads to a relative volume loss of 20 % in the unmineralized fibrocartilage, which is twice as high as in the tendon proper. The scans of the loaded insertions reveal that pressed out liquid accumulates in the retrocalcaneal bursa. These findings contribute to the interpretation of the fibrocartilage as a poroelastic composite inhibiting fast water loss by its low permeability. Therefore, under dynamic loads the fibers could exert pressure on a “water cushion”