Pattern 16.16 Factories

Apply generalizations after you complete the basic design. A wide variety of design patterns are directed at generalization and decouphng. Most notable are Pattern 16.15, Role Decoupling and Pattern 16.16, Factories. 

Pulver-band, m. (Expl.) powder strand, -biatt-chen. n, (Expl.) powder flake, powder grain, -brennztlndung, /. powder-train ignition, -dampf, in. powder smoke, -dlagramm, n. powder pattern, -fabrik, /. powder factory, -fabrikation, /. powder manufacture, -fass, n. powder cask, powder keg. -fiascbe. /. powder bottle (wide-mouthed bottle), pulverfdrmig, a. in the form of powder, powdery, pulverulent. 

Figure 13.4 illustrates some of the factors known to be involved in the development of AD many of the known and putative links between factors are also shown. It should also be noted that the patterns of inter-factor modulation may be either positive or negative. However, it is clear that no single factor or combination of factors can explain all AD cases. It is best to conceptually model AD as a broad end point that can be reached in numerous ways. Similar multi-factorial models have been proposed for schizophrenia and depression (Chapters 11 and 12) and almost certainly underlie every other complex psychobiological concept. 

Air samples collected in one acrylonitrile-fiber plant ranged from 3 to 20 mg/m3 (EPA 1980a). Mean 24-hour acrylonitrile concentrations in atmospheric samples collected within 5 km of 11 factories producing or using acrylonitrile ranged from less than 0.1 to 325 pg/m (Suta 1979). The occurrence of acrylonitrile was correlated to wind patterns the highest concentrations were downwind of and in close proximity to the plant. The median concentration of acrylonitrile for 43 measurements in "source-dominated areas" (i.e., near chemical plants) was 2.1 pg/m (Brodzinsky and Sing 1983). There were no data available on the concentration of acrylonitrile in air near chemical waste sites, but because acrylonitrile is easily volatilized, this is an exposure pathway of concern. 

But there is one case in which this does not work well When you want to create an object, you must say which class you want it to belong to. However, there are a number of patterns, such as Factory, that help localize the dependencies, so that adding a new Shape to the drawing editor (for example) causes only one or two alterations to be necessary to the existing code. 

The lower left panel in Figure 13.2 shows the central composite design in the two factors X, and X2. The factor domain extends from -5 to +5 in each factor dimension. The coordinate axes in this panel are rotated 45° to correspond to the orientation of the axes in the panel above. Each black dot represents a distinctly different factor combination, or design point. The pattern of dots shows a central composite design centered at (Xj = 0, Xj = 0). The factorial points are located 2 units from the center. The star points are located 4 units from the center. The three concentric circles indicate that the center point has been replicated a total of four times. The experimental design matrix is... 

Ike Class of Factorial Designs Square or rectangular patterns in two dimensions, cubic or rectangular parallelopipeds in three dimensions, and the analogous multidimensional figures in 4, 5. .. to... 

A five-factor central composite design consists of the five-factor, two-level factorial, with the centre point and with the star pattern in all five variables. This would ordinarily call for running 32 4- 10 + 4-1-43 conditions, with some replication at the centre. Usually, the half replicate of the factorial plus the star points and centre is enough to give an adequate picture of the relationships. 

Many modifications of the central composite design are possible and may be used to fit specific situations. For example, one of the variables may only have two possible levels. In this case, the portion of the star pattern for this variable would be omitted and the star pattern for the other variables might be run at a selected level of the variable in question. In other cases, the outrigger points may be meaningless for a particular variable, and only the factorial and centre points used. 

The result of the discriminant analysis is shown in Fig. 5. The industrial activities are represented by ellipses of inertia containing the coordinates of industrial categories on the first factorial plane. All the categories largely overlap each other and show that this set of ecotoxicological data could not allow any linkage between the type of industry and the toxicological pattern. 

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