Analysis-by-synthesis

Notice that in example 2, the blend failed content uniformity but the capsules passed. The approach given in the PDA paper [1] applies an analysis by synthesis as follows ... 

The spectral components are quantized and coded with the aim of keeping the noise, which is introduced by quantizing, below the masked threshold. Depending on the algorithm, this step is done in very different ways, from simple block companding to analysis-by-synthesis systems using additional noiseless compression. 

George and Smith, 1992] George, E. B. and Smith, M. J. T. (1992). Analysis-by-synthesis/Overlap-add sinusoidal modeling applied to the analysis and synthesis of musical tones. J. Audio Eng. Soc., 40(6) 497-516. 

Noise allocation followed by scalar quantization and Huffman coding. In this method, no explicit bit allocation is performed. Instead, an amount of allowed noise equal to the estimated masked threshold is calculated for each scalefactor band. The scalefactors are used to perform a coloration of the quantization noise (i.e. they modify the quantization step size for all values within a scalefactor band) and are not the result of a normalization procedure. The quantized values are coded using Huffman coding. The whole process is normally controlled by one or more nested iteration loops. The technique is known as analysis-by-synthesis quantization control. It was first introduced for OCF [Brandenburg, 1987], PXFM [Johnston, 1989b] and ASPEC [Brandenburg et al., 1991], In a practical application, the following computation steps are performed in an iterative fashion ... 

Other coding tools in Layer 3 include a different (nonuniform) quantizer, analysis-by-synthesis control of the quantization noise and Huffman coding of the quantized values to increase the coding efficiency. All these have already been described earlier in this chapter. 

Synthetic biometrics have been used for a while in the analysis-by-synthesis approach, in which synthesis of biometric data can verify the perceptual equivalence between original and synthetic biometric data. For example, facial synthesis can be formulated as deriving a realistic facial image from a symbolic facial expression model. 

The natural world is one of eomplex mixtures petroleum may eontain 10 -10 eomponents, while it has been estimated that there are at least 150 000 different proteins in the human body. The separation methods necessary to cope with complexity of this kind are based on chromatography and electrophoresis, and it could be said that separation has been the science of the 20th century (1, 2). Indeed, separation science spans the century almost exactly. In the early 1900s, organic and natural product chemistry was dominated by synthesis and by structure determination by degradation, chemical reactions and elemental analysis distillation, liquid extraction, and especially crystallization were the separation methods available to organic chemists. 

Analysis proceeds from the assumption that in order to understand a system one must first break it up into its constituent parts. Understanding then comes from the knowledge gained by reconstructing the system. But for systems whose dynamics depend critically on interaction between pai ts, analysis often misses the essential characteristics of the whole system. Synthesis is the complementary act of putting the individual pieces together in order to understand what they do collectively. Understanding complex synthesis requires that both analysis and synthesis be done. 

Guderian, R. Air Pollution by Photochemical Oxidants] Guderian, R. Ed. Ecological Studies Analysis and Synthesis Springer-Verlag New York, NY, 1985 Vol. 52 p 346. 

The chemical analysis by ICP-AES showed that the determined M2+/M3+ molar ratio in Zn2Al (Table 1) was very close to the nominal ratio of the synthesis mixture, and is supporting the XRD results. For Zn2Ga, the Zn/Ga ratio was slightly higher than 2 due to the presence of an excess of ZnO, also evidenced by XRD. ICP-AES analysis of the Rh exchanged LDH indicated a similar Rh content in the two samples (Table 1). The TPPTS Rh (wt%) ratio was found to be a value of 2.83, in agreement with the structure of the expected complex [9c]. 

This same concept applies to spiroannulations of six membered rings and is illustrated in a synthesis of acorenone B 155 as outlined in Scheme 547). The notion of alkylative carbonyl transposition permits the spiro enone 156 to become a logical intermediate. The standard analysis by a retro-aldol process translates the spiro ring system of acorenone B into a geminal alkylation problem as revealed by... 

Scheme 12. Retrosynthetic Analysis and Synthesis of 11-Deoxyprostaglandin E a C4H9Li, CHjMgl then 58 followed by DHP, PPTS, 67% b KF, H20, DMF then nC4H9Li, THF, n-CjH CHO followed by C2H5OH, PPTS, 61% c LAH, THF then TMS-C1, (C2H5)3N, DMSO, 72% " FVT, 100% c LiNH2, liq. NH3, BrCH2CH=CHCH2CH2—CH2-C02CH3,45%...

Scheme 15. Retrosynthetic Analysis and Synthesis of Methyl Trisporate B a C4H9Li then 43 then KH/THF followed by TMS-C1, C5H5N, ether 70% b FVT, 95% CH3OH, HC(OCH,)3, HC1, 68% d CH3MgBr, (dppp)NiCl2, THF, 75% HC1, H20, CH3CN, 100% f See Ref. 975...

Chenchik, A., Moqadam, F. and Siebert, P. A new method for full-length cDNA cloning by PCR. In A Laboratory Guide to RNA Isolation, Analysis and Synthesis. PA. Krieg, (ed.) Wiley Liss, Inc. pp. 273-321, 1996. 

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