Knowledge-based methods

Trochim, W. (2006). Research methods knowledge base Guttman scaling. In www.socialresearchmethods.net. WEB Center for Social Research Methods. 

The classical computer tomography (CT), including the medical one, has already been demonstrated its efficiency in many practical applications. At the same time, the request of the all-round survey of the object, which is usually unattainable, makes it important to find alternative approaches with less rigid restrictions to the number of projections and accessible views for observation. In the last time, it was understood that one effective way to withstand the extreme lack of data is to introduce a priori knowledge based upon classical inverse theory (including Maximum Entropy Method (MEM)) of the solution of ill-posed problems [1-6]. As shown in [6] for objects with binary structure, the necessary number of projections to get the quality of image restoration compared to that of CT using multistep reconstruction (MSR) method did not exceed seven and eould be reduced even further. 

Knowledge-based systems typically use quaHtative methods rather than quantitative ones. For example, consider a simple tank system. The equation describing the flow rate of Hquid out of the tank is given below, where C is the orifice coefficient, d is the diameter of the orifice, and h is the height of Hquid in the tank. Based solely on the form of the equation, a human reasoner can infer that the flow rate F increases monotonically with the height b of Hquid in the tank. 

With this database in hand, a simple question is asked [29] How different is a knowledge-based potential derived from this lattice database compared to the actual energy function used to construct the database If statistical errors are negligible and the knowledge-based method is perfect, the answer is expected to be They are exactly the same. ... 

Shimada J, Ishchenko AV, Shakhnovich El. Analysis of knowledge-based protein-ligand potentials using a self-consistent method. Protein Sci 2000 9 765-75. 

The results discussed in Sections 3.1-3.3 turned out as very valuable with respect to the knowledge about the transition from bulk metal to molecule. The most important method, however, to gain direct information from individual metal nanoparticles on their inner electronic life is the tunnelling spectroscopy. The method is based on the single-electron tunnelling (SET) through an intermediate island between two metal electrodes as is indicated in Figure 10. 

W. Pennincks, P. Vankeerberghen, D.L. Massart and J. Smeyers-Verbeke, A knowledge-based computer system for the detection of matrix interferences. Atomic Absorption Spectrometric Methods, J. Anal. Atom. Spectrom. inch Atomic Absorption Spectrom. Updates, 10 (3) (1995) 207-214. 

In many applications of quantum mechanics to chemical systems, a knowledge of the ground-state energy is sufficient. The method is based on the variation theorem-, if 0 is any normalized, well-behaved function of the same variables as and satisfies the same boundary conditions as then the quantity = (p H (l)) is always greater than or equal to the ground-state energy Eq... 

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