Types of features

One of the fundamental problems in unit selection is that tiie specification items lack tiie acoustic description(s) that would make matching them witii units a fairly easy process. We can approach this problem in two ways. Firstly, we can just ignore tiie fact tiiat tiie units have acoustic features and match on the linguistic features alone. Alternatively, we can try to perform a partial synthesis, whereby we attempt to generate some or all of the acoustic features and then match these with the acoustic features derived by signal processing from the waveforms. 

To demonstrate the issue of choice of feature system, let us consider how to represent intonation in the specification. In second-generation systems and in some unit-selection systems, this is represented solely by the FO contour (sampled in some appropriate way). However, as we saw in Sections 9.4 and 9.5, when FO contours are generated, they are generated from other features that have been calculated previously. Since we cannot actually generate new information, the FO contour is clearly just a transformation of the information contained in the original features into a different form. Hence there is no 

The choice of features is therefore dependent on many factors and we cannot a priori say that one approach is better than the others. However, we should note that that there has been a continual move in TTS away from exact specification of low-level features towards using higher-level features, see for example [65], [92], [ 103], [43 6], [447]. Given 

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The occurrence of fine structures has already been noted in the sections on spectral information and ionization losses (Sects. 2.5.3 and 2.5.3.2). In the following text some principal considerations are made about the physical background and possible applications of both types of feature, i. e. near-edge and extended energy-loss fine structures (ELNES/EXELFS). A wealth of more detailed information on their usage is available, especially in textbooks [2.171, 2.173] and monographs [2.210-2.212]. 

Model described in text. b Many of the features of the thiophene photographs are of types known to be difficult to measure. Here the inner rings and the components of the two doublets have been thrown out of the average, since measurements of both types of features are known to be unreliable. The effect of the choice of rings to be thrown out is here somewhat greater than usual and may amount to 0.005 in s/sa. 

As was noted above, STM images are often strongly dependent both on Fbias and on the type of feature being imaged at the surface. As a result, the image is often not a simple topographical map of the surface features. Consider, for example, a surface having an adsorbed atom with an excess of... 

The final layer of security is provided by properly designed interior features of buildings. Examples of these types of features include internal doors and walls, equipment cages, and backup or redundant equipment. 

The application of methods of multivariate statistics (here demonstrated with examples of cluster analysis, multivariate analysis of variance and discriminant analysis, and principal components analysis) enables clarification of the lateral structure of the types of feature change within a test area. 

Unity 3-D rigid screens [15] are based on a single conformation of a molecule, usually that conformation that is generated by CONCORD [19]. Unity 3-D flexible screens record all possible distances between the same types of features (atom types, rings and planes) based on the incremental rotation of all the rotatable bonds between the two features. 

Comparison of methods with the same type of feature selection forced on all methods, rather than letting each method do what it does best. 

The type of feature requiring the greatest exposure to destroy the gel is an isolated line, because it receives less backscattered energy than any other type of feature. From the results of section (a) it is known that the required dose, Q., is 85yC/cm2 in the absence of flood exposure. For a flood exposure dose, Qf, the new patterning dose, Qp, required to clear the line is... 

An isolated unexposed space is the type of feature with the worst possible contrast in electron beam lithography since it receives more backscattered energy than any other type of feature (16). For such a feature the ratio of the energy deposited in the adjacent exposed region to that deposited in the nominally unexposed region, after both flood and patterning exposures, is... 

Scales Above the Micron Scale. Much can be learned about the workings of a material with little more than an optical microscope and a well-polished sample. One of the first features of a material that will be evident upon inspection via optical means are the type of features shown in fig. 10.2 which reveals a polycrystalline microstructure. Of course, we well know that what we are seeing is evidence of the polycrystallinity of the material. The grain boundaries that separate different grains are clearly evident on the crystal surface. We can also see that depending upon the life history of the material, the grain size can vary considerably. 

The most direct evidence of the crystallinity in polymers is provided by x-ray diffraction studies. The x-ray patterns of many crystalline polymers show both sharp features associated with regions of three-dimensional order, and more diffuse features characteristic of molecularly disordered substances like liquids. The occurrence of both types of feature is evidence that ordered regions (called crystallites) and disordered regions coexist in most crystalline polymers. X-ray scattering and electron microscopy have shown that the crystallites are made up of lamellae which are built-up of folded polymer chains as explained below. 

Type of feature Depth of permanent nutricline Depth of deep chlorophyll maximum Integrated chlorophyll a (mg nT2) Reference... 

Olson and Koch have previously pointed out this type of feature in their studies of the (Scheme 1)... 

The two major categories of polymer composite used in aerospace are laminates and sandwich stmctures, which require some differences in NDT inspection methods. The inspection of choice at the time of manufacture may be different from the inspection of choice for in-service assessments. The form of the stmcture determines the types of features of concern and the NDT techniques that may be apphed to detect and measure them. Table 15.1 summarizes some general thoughts and considerations on NDT of polymer composite stmctures. American Society for Testing and Materials (ASTM) also provides guidance on NDT for polymer composites [12]. The primary concerns in laminates are voids and porosity, inclusions, delamination, the fiber-to-resin ratio, and wrinkles (wavy or out-of-plane ply). Ultrasound is the predominate method for composite laminate inspection. In sandwich structures, the core material-to-facesheet bond, core condition, and fluid ingress are the usual concerns. 

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