Statistical Modelling in Materials Research

1992 ◽  
Vol 291 ◽  
Author(s):  
G. Pouskouleli ◽  
A. Ahmad ◽  
T.A. Wheat ◽  
S. Varma ◽  
S.E. Prasad
Keyword(s):  
Process Parameters ◽  
Statistical Modelling ◽  
Fractional Factorial ◽  
Materials Properties ◽  
Number Of Factors ◽  
Factorial Matrix ◽  
Materials Research ◽  
Experimental Trials ◽  
Full Factorial

ABSTRACTThe role of statistical modelling in materials research is examined. It is shown that considerable benefits can be derived by following an appropriate full factorial design, in which a number of factors (process parameters) are varied simultaneously while the responses (materials properties) are monitored. It is also shown that by using a fractional factorial matrix, essentially the same conclusions can be drawn with a significantly smaller number of experimental trials. Examples drawn from recent materials research on glasses and ceramics are presented to demonstrate the effectiveness of this approach.

Exploring the Role of Interaction Effects in Visual Conjoint Analysis

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Brian Sylcott ◽  
Jeremy J. Michalek ◽  
Jonathan Cagan
Keyword(s):  
Conjoint Analysis ◽  
Consumer Preferences ◽  
Consumer Preference ◽  
Interaction Effects ◽  
Fractional Factorial ◽  
Main Effects ◽  
Full Factorial ◽  
Biased Estimates ◽  
Data Requirements

In conjoint analysis, interaction effects characterize how preference for the level of one product attribute is dependent on the level of another attribute. When interaction effects are negligible, a main effects fractional factorial experimental design can be used to reduce data requirements and survey cost. This is particularly important when the presence of many parameters or levels makes full factorial designs intractable. However, if interaction effects are relevant, main effects design can create biased estimates and lead to erroneous conclusions. This work investigates consumer preference interactions in the nontraditional context of visual choice-based conjoint analysis, where the conjoint attributes are parameters that define a product's shape. Although many conjoint studies assume interaction effects to be negligible, they may play a larger role for shape parameters. The role of interaction effects is explored in two visual conjoint case studies. The results suggest that interactions can be either negligible or dominant in visual conjoint, depending on consumer preferences. Generally, we suggest using randomized designs to avoid any bias resulting from the presence of interaction effects.

Generation of Two-Level Cost Optimal Fractional Factorials

1978 ◽  
Vol 22 (1) ◽  
pp. 599-599
Author(s):  
Joseph J. Pignatiello
Keyword(s):  
Mathematical Programming ◽  
Programming Problem ◽  
Minimum Cost ◽  
Fractional Factorial ◽  
Factorial Experiment ◽  
Mathematical Programming Problem ◽  
Fractional Factorials ◽  
Number Of Factors ◽  
Main Effects ◽  
Full Factorial

It is assumed that, in a 2k factorial experiment, there are different costs per observation at each of the factor combinations. When the number of factors, k, increases, the total number of observations in the full factorial increases rapidly as does the expense of observing all observations in the full factorial. If the experimenter can assume certain classes of higher-order interactions are negligible, then advantage may be taken by observing measurements from an orthogonal fractional factorial. For any “1/2p” fraction of the full factorial, a 2k-p experiment, there are 2p feasible orthogonal fractions that could be selected at random. This paper develops an algorithm for generating the minimum cost such fraction in an efficient way. The problem is formulated as a mathematical programming problem subject to a resolution III constraint (main effects unconfounded). Computational experience is presented.

scholarly journals The search for new materials and the role of novel processing routes

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Peter J. Wellmann
Keyword(s):  
Materials Science ◽  
Research Society ◽  
Subsequent Treatment ◽  
European Council ◽  
Trial And Error ◽  
Human History ◽  
New Materials ◽  
Materials Research ◽  
Novel Processing

AbstractThroughout human history, most further developments or new achievements were accompanied by new materials or new processes that enabled the technologic progress. With concrete devices and applications in mind, synthesis and subsequent treatment of materials naturally went along with the progress. The aim of the underlying article is to spot the role of optimization, of discovery, of trial-and-error approaches, of fundamentals and curiosity driven design and development. In a consecutive examination, five missions addressing the challenges facing our world (identified by the European Council) will be cross linked with seven topical areas from materials science defined by the European Materials Research Society. The scope of this examination is to identify approaches and methods to further develop and innovate materials which form the basis of the anticipated solutions.

scholarly journals Richness of Rhizosphere Organisms Affects Plant P Nutrition According to P Source and Mobility

Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 157
Author(s):  
Jean Trap ◽  
Patricia Mahafaka Ranoarisoa ◽  
Usman Irshad ◽  
Claude Plassard
Keyword(s):  
Careful Consideration ◽  
Soil Conditions ◽  
Organic P ◽  
P Nutrition ◽  
Soil P ◽  
P Acquisition ◽  
Complex Interactions ◽  
Experimental Trials ◽  
The Relationship

Plants evolve complex interactions with diverse soil mutualist organisms to enhance P mobilization from the soil. These strategies are particularly important when P is poorly available. It is still unclear how the soil P source (e.g., mineral P versus recalcitrant organic P) and its mobility in the soil (high or low) affect soil mutualist biological (ectomycorrhizal fungi, bacteria and bacterial-feeding nematodes) richness—plant P acquisition relationships. Using a set of six microcosm experiments conducted in growth chamber across contrasting P situations, we tested the hypothesis that the relationship between the increasing addition of soil mutualist organisms in the rhizosphere of the plant and plant P acquisition depends on P source and mobility. The highest correlation (R2 = 0.70) between plant P acquisition with soil rhizosphere biological richness was found in a high P-sorbing soil amended with an organic P source. In the five other situations, the relationships became significant either in soil conditions, with or without mineral P addition, or when the P source was supplied as organic P in the absence of soil, although with a low correlation coefficient (0.09 < R2 < 0.15). We thus encourage the systematic and careful consideration of the form and mobility of P in the experimental trials that aim to assess the role of biological complexity on plant P nutrition.

scholarly journals Role of laser powder bed fusion process parameters in crystallographic texture of additive manufactured Nb-48Ti alloy

2021 ◽  
Author(s):  
Rafael de Moura Nobre ◽  
Willy Ank de Morais ◽  
Matheus Tavares Vasques ◽  
Jhoan Guzmán ◽  
Daniel Luiz Rodrigues Junior ◽  
...  
Keyword(s):  
Process Parameters ◽  
Crystallographic Texture ◽  
Fusion Process ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

scholarly journals SAT0636-HPR PATIENT EXPERIENCE WITH THE PRESCRIPTION, INFORMATION AND USE OF METHOTREXATE

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1277.3-1278
Author(s):  
T. Oton ◽  
L. Carmona ◽  
J. L. Andréu Sánchez
Keyword(s):  
Side Effects ◽  
Focus Groups ◽  
Rheumatic Diseases ◽  
Lupus Erythematosus ◽  
Physical Symptoms ◽  
Number Of Factors ◽  
Graphic Information ◽  
Main Barrier ◽  
And Training

Background:Methotrexate (MTX) is currently a mainstream drug in the treatment of rheumatic diseases. However, the response to MTX is not universal and may be conditioned by a number of factors, among which adherence could be crucial.Objectives:The aim of this study is to explore adherence to MTX in patients with rheumatic diseases, facilitators and perceived when taking and maintaining the prescription.Methods:A qualitative study of content analysis was performed. Focus groups with patients taking either oral or subcutaneous MTX (being the main or coadjuvant treatment) for any rheumatic disease was performed. The groups were moderated by a rheumatologist that was unknown for the patients. The speech was recorded and transcribed. Subsequently, an inductive coding was performed with the help of Atlas.ti and main themes and sub-themes were extracted, with examples of verbatim anonymized speech.Results:Three focus groups were conducted, with a total of 12 participants, of whom eight were women, seven had rheumatoid arthritis, three had psoriatic arthritis, one had spondyloarthritis, and one had systemic lupus erythematosus. All patients reported an adequate adherence to treatment. The barriers identified were: information in the leaflet, technical language in the consults, difficult access to doctor´s appointment, social environment, side effects and the subcutaneous device. As facilitators, the following aspects were discussed: good predisposition of the physician, reliable graphic information, role of associations and partners support.The unmet needs detected were: problems with travelling, protocols for eventualities, absence of a plan of care, neglection of “non-physical” symptoms, disinformation on side effects and training in complementary aspects.Conclusion:Getting reliable information was the main barrier identified. The environment and side effects may also negatively impact on adherence. Shared decision making is a goal to be achieved in the future in these patients.Disclosure of Interests:Teresa Oton Consultant of: Novartis Farmaceutica, SA, Pfizer, S.L.U., Merck Sharp & Dohme España, S.A., Roche Farma, S.A, Sanofi Aventis, AbbVie Spain, S.L.U., and Laboratorios Gebro Pharma, SA (All trhough institution), Loreto Carmona Grant/research support from: Novartis Farmaceutica, SA, Pfizer, S.L.U., Merck Sharp & Dohme España, S.A., Roche Farma, S.A, Sanofi Aventis, AbbVie Spain, S.L.U., and Laboratorios Gebro Pharma, SA (All trhough institution), José Luis Andréu Sánchez: None declared

Role of perinatal factors in the formation of neurocognitive disorders in children with ADHD

2020 ◽  
Vol 18 (5) ◽  
pp. 82-87
Author(s):  
E. A. MOROZOVA ◽  
◽  
A. A. MADIAKINA ◽  
M. V. BELOUSOVA ◽  
M. A. UTKUZOVA UTKUZOVA ◽  
...  
Keyword(s):  
Attention Deficit Disorder ◽  
Neurological Disorders ◽  
Neuropsychological Testing ◽  
Cognitive Status ◽  
Perinatal Factors ◽  
Attention Disorders ◽  
Children With Adhd ◽  
Group I ◽  
Number Of Factors

The article presents the results of studying the influence of perinatal factors and neurological disorders on the formation of attention deficit disorder (ADHD) in children; the results of assessing the cognitive status and attention indicators in children of the studied groups are presented. The purpose was to study the perinatal causes, neurological manifestations, and cognitive status in children with ADHD. Material and methods. The study involved 172 children aged 6 to 17 years with a clinical diagnosis of ADHD. The research methods included: clinical and anamnestic method with an emphasis on perinatal aspects; classical neurological examination; neuropsychological testing. Results. The influence of antenatal factors and neurological disorders at the 1st year of life on the formation of ADHD was revealed. The features of the cognitive status and attention indicators of children of both groups were studied. Conclusions. A burdened perinatal history and neurological disorders developing against this background lead to an early manifestation of ADHD symptoms. The combination of neurological symptoms with low cognitive indicators and significant attention disorders in children of group I determines the low success of children in mastering educational programs. The presence of a burdened perinatal history (for a number of factors) should be considered as a predictor of the formation of ADHD, in order to further select children at risk for early preventive work.

Sign in / Sign up

Export Citation Format

Share Document