366,961 research outputs found
Practical inference from industrial split-plot designs.
No full textMany industrial response surface experiments are deliberately not conducted in a completely randomized fashion. This is because some of the factors investigated in the experiment are hard to change. The resulting experimental design then is of the split-plot type and the observations in the experiment are in many cases correlated. A proper analysis of the experimental data therefore is a mixed model analysis involving generalized least squares estimation. Many people, however, analyze the data as if the experiment was completely randomized, and estimate the model using ordinary least squares. The purpose of the present paper is to quantify the differences in conclusions reached from the two methods of analysis and to provide the reader with guidance for analyzing split-plot experiments in practice. The problem of choosing the number of degrees of freedom for significance tests in the mixed model analysis is discussed as well.Containment method; Data; Design; Experimental design; Factors; Fashion; Generalized least squares; Least-squares; Method of Kenward and Roger; Methods; Model; Ordinary least squares; Residual method; Satterthwaite's method; Split-plot experiment; Squares;
Testing for lack of fit in blocked and split-plot response surface designs
No full textTextbooks on response surface methodology emphasize the importance of lack-of-fit tests when fitting response surface models, and stress that, to be able to test for lack of fit, designed experiments should have replication and allow for pure-error estimation. In this paper, we show how to obtain pure-error estimates and how to carry out a lack-of-fit test when the experiment is not completely randomized, but a blocked experiment, a split-plot experiment, or any other multi-stratum experiment. Our approach to calculating pure-error estimates is based on residual maximum likelihood (REML) estimation of the variance components in a full treatment model. It generalizes the one suggested by Vining et al. (2005) in the sense that it works for a broader set of designs and for replicates other than center point replicates. Our lack-of-fit test also generalizes the test proposed by Khuri (1992) for data from blocked experiments because it exploits replicates other than center point replicates and works for split-plot and other multi-stratum designs as well. We provide analytical expressions for the test statistic and the corresponding degrees of freedom, and demonstrate how to perform the lack-of-fit test in the SAS procedure MIXED. We re-analyze several published data sets and discover a few instances in which the usual response surface model exhibits significant lack of fit
Plot- and plant-level sampling requirements.
No full text(a) The five shade tree treatments are represented: Erythrina poeppigiana (Legume 1), Terminalia amazonia (Timber), Chloroleucon eurycyclum (Legume 2), E. poeppigiana + T. amazonia (Legume 1 + Timber) and E. poeppigiana + C. eurycyclum (Legume 1 + Legume 2). Dotted boxes represent study plot boundaries for all measurements. (b) Coffee plant profile with each of the plant strata highlighted (top, middle, bottom) from which leaves were sampled.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Narrative support for technical documents: Formalising Rhetorical Structure Theory
No full textBusiness Process Re-engineering (BPR) is an area that requires a lot of technical documents and an important feature of a well-written document is a coherent narrative. Even though computer software has helped authors in many other aspects of writing, support for document narratives is almost non-existent. Therefore, we introduce CANS (Computer-Aided Narrative Support), a tool that uses Rhetorical Structure Theory to enhance the narrative of a document. From this narrative, the tool generates questions to prompt the author for the content of the document. CANS also allows the author to explore alternative narratives for a document. A catalogue of predefined narrative structures for popular types of documents is provided too. Our tool is still in its rudimentary stages but sufficiently complete to be demonstrated
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Player agency in interactive narrative: audience, actor & author
No full textThe question motivating this review paper is, how can
computer-based interactive narrative be used as a constructivist learn-
ing activity? The paper proposes that player agency can be used to
link interactive narrative to learner agency in constructivist theory,
and to classify approaches to interactive narrative. The traditional
question driving research in interactive narrative is, ‘how can an in-
teractive narrative deal with a high degree of player agency, while
maintaining a coherent and well-formed narrative?’ This question
derives from an Aristotelian approach to interactive narrative that,
as the question shows, is inherently antagonistic to player agency.
Within this approach, player agency must be restricted and manip-
ulated to maintain the narrative. Two alternative approaches based
on Brecht’s Epic Theatre and Boal’s Theatre of the Oppressed are
reviewed. If a Boalian approach to interactive narrative is taken the
conflict between narrative and player agency dissolves. The question
that emerges from this approach is quite different from the traditional
question above, and presents a more useful approach to applying in-
teractive narrative as a constructivist learning activity
Plot-based urbanism : towards time-consciousness in place-making
No full textSome of us have recently argued that what we still miss is the serious consideration of the factor of time in urbanism, or, in other words, a deeper "time conscious" approach (Thwaites, Porta, Romice, & Greaves, 2008). Inevitably, that means focusing on change as the essential dynamic of evolution in the built environment, which in turn leads to re-addressing concepts like control, self-organization and community participation. After time and change have been finally firmly placed at the centre stage, the whole discipline of urban planning and design, its conceptual equipment as well as its operational toolbox, reveals its weaknesses under a new light and calls for the construction of a different scenario. This paper poses the problem of this scenario in disciplinary terms, it argues about its premises and outlines its essential features. The scope of this paper is not to deliver a comprehensive model for a new approach to urban planning and design, but to set the right framework and rise the right questions so that we can start thinking of issues such as urban regeneration, informal settlements and massive urbanization, community participation and representation, beauty and humanity in space, in a different way
Parameters of plant-caterpillar interaction networks based on the plot-based data (Plots) and simulated non-plot-based data where individual tree species were sampled with equal effort.
No full textThe simulated data represent a non-plot-based approach focusing on locally abundant tree species representing a certain amount of the foliage in the forest (20, 40, 60, or 80% species) or a representative selection of tree families (Families). The results are based on Yawan primary forest dataset from Redmond et al. [23]. The compared network parameters include connectance (A), web asymmetry (B), nestedness (C), species richness of caterpillars (D), weighted generality (E), and weighted vulnerability (F). All simulated datasets were rarefied to the average leaf area of a 0.1 ha plot. All rarefactions were repeated 100-times. Points show mean. Bars show 95% confidence intervals.</p
Superare il plot tradizionale: l'adozione delle forme musicali nel romanzo contemporaneo
No full text"Pro e contro la trama", Atti del convegno internazionale «Pro e contro la trama/ Writing for and against the plot»,W. Nardon e C.Tirinanzi Medici (a cura di), Editrice Università diTrento – Dipartimento di Lettere e Filosofia, 2012, pp. 111-119
- …
