This article raises a number of questions about the current unified theory of test validity that has construct validity at its center. The authors suggest a different way of conceptualizing the problem of establishing...
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This article raises a number of questions about the current unified theory of test validity that has construct validity at its center. The authors suggest a different way of conceptualizing the problem of establishing validity by considering whether the focus of the investigation of a test is internal to the test itself or focuses on constructs and relationships that are external to the test. They also consider whether the perspective on the test examination is theoretical or practical. The resulting taxonomy, encompassing both investigative focus and perspective, serves to organize a reconceptualization of the field of validity studies. The authors argue that this approach, together with changes in the rest of the terminology regarding validity, leads to a more understandable and usable model.
While short-term population dynamical consequences of harvesting havebeen studied for a long time,it is only recently that the potentiallyimportant ensuing evolutionary responses have started to receive *** now,most s...
While short-term population dynamical consequences of harvesting havebeen studied for a long time,it is only recently that the potentiallyimportant ensuing evolutionary responses have started to receive *** now,most studies of harvesting induced evolutionhave focused on a single species in isolation,leaving potentially important coevolutionary interactions *** present a model for the origin and evolution of size-structured food webs based on Lotka-Volterra ***-dependent interactions and small mutations in body size leads to food webs with three to four trophic *** subjecting the resulting communities to various harvesting regimes,the consequences for population dynamics and evolutionary dynamics are analyzed.
The following article presents a computational methodology to assist the assessment of tympanic pathologies, particularly chronic otitis media, based on digital otoscopic images. A computational system which implement...
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The following article presents a computational methodology to assist the assessment of tympanic pathologies, particularly chronic otitis media, based on digital otoscopic images. A computational system which implements the methodology is described. This approach does not impose additional effort to the acquisition protocol and diagnosis of tympanic pathologies. In preliminary tests, it has shown precision and easiness of use. The presented methodology and system were tested by the Otitis Media Center of Brazil (***) with a case base of 660 patients, resulting in 1320 bilateral tympanic images.
Molecular profiling strategies generally apply either transcriptomic or proteomic technologies for dissection of aberrant expression patterns between normal and diseased samples. Although studies in yeast ( S. cerevis...
Molecular profiling strategies generally apply either transcriptomic or proteomic technologies for dissection of aberrant expression patterns between normal and diseased samples. Although studies in yeast ( S. cerevisiae ) demonstrate excellent concordance between gene/protein abundance, the lack of integrated comparisons using human systems prompted us to stringently dissect these relationships in a cellular model system (platelets) devoid of active transcriptional activity. Highly-purified platelets from four healthy donors were pooled for proteomic analyses which were completed in duplicate using tryptic digestion of 100 mg cytoplasmic fractions, followed by cation exchange liquid chromatography coupled to tandem mass spectrometry (μLC-MS/MS). Spectral (peptide) counts were used as a semi-quantitative means of establishing protein abundance among normalized MS data sets, with excellent concordance between platelet runs (Spearman rank correlation r = 0.87, p <0.0001). Microarray data derived from five platelet apheresis donors were hybridized to the Affymetrix HU133a gene chip, and relative transcript abundance established by rank-ordering the unique, normalized set of non-redundant mRNAs (N=1240). Two comprehensive bioinformatics approaches using either platelet-restricted or genome-wide relational databases were additive in identifying 690 unique platelet proteins, representing increase of 230% or 131% to either approach alone. Of the identified proteins, 72% had a corresponding mRNA transcript, although a smaller fraction of mRNAs (41%) had a corresponding protein. The calculated codon adaptation index (CAI) for the 156 highest- and the 156 lowest-expressed platelet transcripts predicted strong correlation to protein abundance. Spearman correlations on data rank-ordered by either protein or transcript abundance demonstrated a maximal correlation coefficient of 0.44 (p =0.034) for an 18-member protein subset (higher protein abundance), although the 20 most abund
In this paper, we describe how an active radar/sonar imaging problem may be formulated as a virtual passive sensor array processing problem. We consider an active sensing problem where it is desired to form a range-Do...
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In this paper, we describe how an active radar/sonar imaging problem may be formulated as a virtual passive sensor array processing problem. We consider an active sensing problem where it is desired to form a range-Doppler image at a slow- time rate, even though the radar/sonar can transmit pulses at a fast time rate. By transmitting pulses at the fast time rate we can estimate the second-order statistics of an ambiguity vector, calculated at a coarse resolution. As we show this ambiguity vector plays the role of an array snapshot vector in passive sensor array processing. The noise free version of this ambiguity vector acts as a signature vector or steering vector, which can be steered around in delay and Doppler at a fine resolution to produce an image. We employ a MVDR-like principle to generate high resolution delay-Doppler images.
In this paper we study convergence of the max-product (MP) algorithm on general graphs with cycles. Our analysis follows analogously to that given for the convergence of the sum-product algorithm. We do not work with ...
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ISBN:
(纸本)142440505X
In this paper we study convergence of the max-product (MP) algorithm on general graphs with cycles. Our analysis follows analogously to that given for the convergence of the sum-product algorithm. We do not work with Gibbs measures but instead we introduce and work with local maxifiers. The contributions of this paper include: reformulation of the MP algorithm on cyclic graphs as max-marginalization on an associated computation tree; existence of local maxifiers and proof that uniqueness of the local maxifier is sufficient for convergence of MP; a Gibbsian theory of local maxifiers and interpretation as operators; an example of non-uniqueness which does not exhibit a phase transition like its Gibbs measure counterpart; and insights into the limitations of Dobrushin-type uniqueness conditions
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