Cluster visualization

Several different clustering visualization techniques are available for representing knowledge or textual analysis [73]. The same techniques used to map the domain structure of the literature can also be used for text clustering. Various types of data such as author co-citation, citation links, and themes can be mapped into two or three dimensions to present clusters visually. 

SONNIA can be employed for the classification and clustering of objects, the projection of data from high-dimensional spaces into two-dimensional planes, the perception of similarities, the modeling and prediction of complex relationships, and the subsequent visualization of the underlying data such as chemical structures or reactions which greatly facilitates the investigation of chemical data. 

A visual inspection of a two-sample chart provides an effective means for qualitatively evaluating the results obtained by each analyst and of the capabilities of a proposed standard method. If no random errors are present, then all points will be found on the 45° line. The length of a perpendicular line from any point to the 45° line, therefore, is proportional to the effect of random error on that analyst s results (Figure 14.18). The distance from the intersection of the lines for the mean values of samples X and Y, to the perpendicular projection of a point on the 45° line, is proportional to the analyst s systematic error (Figure 14.18). An ideal standard method is characterized by small random errors and small systematic errors due to the analysts and should show a compact clustering of points that is more circular than elliptical. 

The two main amphibole asbestos fibers are amosite and crocidoHte, and both are hydrated siHcates of iron, magnesium, and sodium. The appearance of these fibers and of the corresponding nonfibrous amphiboles is shown in Figure 1. Although the macroscopic visual aspect of clusters of various types of asbestos fibers is similar, significant differences between chrysotile and amphiboles appear at the microscopic level. Under the electron microscope, chrysotile fibers are seen as clusters of fibrils, often entangled, suggesting loosely bonded, flexible fibrils (Fig. 2a). Amphibole fibers, on the other hand, usually appear as individual needles with a crystalline aspect (Fig. 2b). 

The Ke-in.-diameter pits are clustered into groups near the center and along the edges of the bore (Fig. 12.12). The interior of the pits is jagged and free of deposits or visually observable corrosion products. 

Among cluster probabilities derived by the PPM, multibody correlations including triangle and tetrahedron cluster probabilities are not input in the simulation procedure. It is, however, worth noting that the agreements between the calculated multibody correlations and resultant ones in the simulated crystal are fairly reasonable. This is rather encouraging to go further discussions of the visualized configuration. 

Fig. 6.18 Scheme of explosive boiling J micro-channel, 2 main area of visual observation, 3 ONB point, 4 elongated cylindrical bubble, 5 liquid in front of the bubble, 6 vapor, 7 liquid droplets and clusters. Reprinted from Hetsroni et al. (2005) with permission... 

The second cluster of neurons lies more caudally, near the pons, in the pedunculo-pontine (PPT) and laterodorsal tegmental (LDT) nuclei (see Fig. 22.6) and could be regarded as part of the ARAS (see McCormick 1992). It innervates the non-specific thalamic nuclei as well as some more specific ones like the lateral geniculate nucleus (visual pathway), the pontine reticular formation and occipital cortex. Because long... 

Hierarchical methods are preferred when a visual representation of the clustering is wanted. When the number of objects is not too large, one may even compute a clustering by hand using the minimum spanning tree. 

To assess homogeneity, the distribution of chemical constituents in a matrix is at the core of the investigation. This distribution can range from a random temporal and spatial occurrence at atomic or molecular levels over well defined patterns in crystalline structures to clusters of a chemical of microscopic to macroscopic scale. Although many physical and optical methods as well as analytical chemistry methods are used to visualize and quantify such spatial distributions, the determination of chemical homogeneity in a CRM must be treated as part of the uncertainty budget affecting analytical chemistry measurements. 

Initial work-up for a woman presenting with a lesion or symptoms suggestive of breast cancer should include a careful history, physical examination of the breast, three-dimensional mammography, and possibly other breast imaging techniques such as ultrasound. Most (80% to 85%) breast cancers can be visualized on a mammogram as a mass, a cluster of calcifications, or a combination of both. Breast biopsy is indicated for... 

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