Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Information Principle

We have already seen hints of the kinds of theories that are possible using the first axiom see Kantor s Information Mechanics (section 12.4.5), Stonier s Information Physics (section 12.4.6) and Frieden s Extreme Physics Information Principle (section 12.4.7). Minsky, Zuse and Fredkiii, among many others, have speculated on a CA-like dynamics of primitive information (see section 12.6). [Pg.699]

E. Ertin, J. W. Fisher, and L. C. Potter, Maximum mutual information principle for dynamic sensor query problems , in Proceedings of the 2nd International Workshop on Information Processing in Sensor Networks, Palo Alto, USA, April 2003, pp. 405-416. [Pg.117]

What principle of classification or division will you use Why is this a useful or informative principle for your particular topic and readers ... [Pg.265]

Recall and recognition of facts information, principles, laws and theories of chemistry. [Pg.163]

The solution of a protein crystal structure can still be a lengthy process, even when crystals are available, because of the phase problem. In contrast, small molecule (< 100 atoms) structures can be solved routinely by direct methods. In the early fifties it was shown that certain mathematical relationships exist between the phases and the amplitudes of the structure factors if it is assumed that the electron density is positive and atoms are resolved [255]. These mathematical methods have been developed [256,257] so that it is possible to solve a small molecule structure directly from the intensity data [258]. For example, the crystal structure of gramicidin S [259] (a cyclic polypeptide of 10 amino acids, 92 atoms) has been solved using the computer programme MULTAN. Traditional direct methods are not applicable to protein structures, partly because the diffraction data seldom extend to atomic resolution. Recently, a new method derived from information theory and based on the maximum entropy (minimum information) principle has been developed. In the immediate future the application will require an approximate starting phase set. However, the method has the potential for an ab initio structure determination from the measured intensities and a very small sub-set of starting phases, once the formidable problems in providing numerical methods for the solution of the fundamental equations have been solved. [Pg.406]

It has recently been observed [22,26] that the stockholder principle of equation (91b) in fact states the equality between the local conditional probabilities (D°(r) = p°(alr) = p°(r) and Da(r) = p(alr) = p(r), that an electron found at a given location in space originates from the specified free or bonded subsystem. Thus, a restatement of the information principle, more appropriate to justify the stockholder rule, should be in terms of these conditional probabilities. Indeed, for a given location in space the following local variational principle is satisfied [26] ... [Pg.154]

The Information Principle - Effective communication increases motivation. [Pg.320]

K. P. Jantke. Algorithmic learning from incomplete information Principles and problems. In J. Dassow and J. Kelemen (eds). Machines, Languages, and Complexity, pp. 188-207. LNCS 381, Springer-Verlag, 1989. [Pg.227]

NalewajsM RF (2003) Information principles in the theory of electronic stracture. Chem Phys... [Pg.240]

The Information Principle Effective communication increases motivation. When people understand clearly the results they try to accomplish and how they contribute to those results, they are more highly motivated. In addition, the person who makes a sincere effort to keep people informed, and to truly Hsten to them, is telling them, 1 think you are important. I want to be sure you and 1 both know whaf s going on. ... [Pg.196]

Article is denoted to the investigation and the creation of the new ultrasonic and information technologies (IT) and the technical methods of non-destructive evaluation (NDE) of material state in the product, which are based on principles of ultrasonic computing tomography (USCT). These results concern two important questions ... [Pg.247]

As on previous occasions, the reader is reminded that no very extensive coverage of the literature is possible in a textbook such as this one and that the emphasis is primarily on principles and their illustration. Several monographs are available for more detailed information (see General References). Useful reviews are on future directions and anunonia synthesis [2], surface analysis [3], surface mechanisms [4], dynamics of surface reactions [5], single-crystal versus actual catalysts [6], oscillatory kinetics [7], fractals [8], surface electrochemistry [9], particle size effects [10], and supported metals [11, 12]. [Pg.686]

Acronym Full name Principle of measurement Key information... [Pg.1852]

Abstract. This paper presents results from quantum molecular dynamics Simula tions applied to catalytic reactions, focusing on ethylene polymerization by metallocene catalysts. The entire reaction path could be monitored, showing the full molecular dynamics of the reaction. Detailed information on, e.g., the importance of the so-called agostic interaction could be obtained. Also presented are results of static simulations of the Car-Parrinello type, applied to orthorhombic crystalline polyethylene. These simulations for the first time led to a first principles value for the ultimate Young s modulus of a synthetic polymer with demonstrated basis set convergence, taking into account the full three-dimensional structure of the crystal. [Pg.433]

All three tasks are generally too complicated to be solved from first principles. They are, therefore, tackled by making use of prior information, and of information that has been condensed into knowledge. The amount of information that has to be processed is often quite large. At present, more than 41 million different compounds are known all have a series of properties, physical, chemical, or biological all can be made in many different ways, by a wide range of reactions all can be characterized by a host of spectra. This immense amount of information can be processed only by electronic means, by the power of the computer. [Pg.4]

The program system COBRA [118, 119] can be regarded as a rule- and data-based approach, but also applies the principles of fragment-based (or template-based) methods extensively (for a detailed description sec Chapter 11, Sections 7.1 and 7.2 in the Handbook). COBRA uses a library of predefined, optimized 3D molecular fragments which have been derived from crystal structures and foi ce-field calculations. Each fi agment contains some additional information on... [Pg.98]

The relative molecular dynamics fluctuations shown in Figure 7-17 can be compared with the crystallographic B-factors, which are also called temperature factors. The latter name, especially, indicates the information content of these factors they show how well defined within the X-ray structure the position of an atom is. Atoms with high temperature have an increased mobility. In principle, this is the same information as is provided by the molecular dynamics fluctuations. Using Eq. (48), the RMS fluctuation of an atom j can be converted into a B-factor... [Pg.373]

On the other hand, techniques like Principle Component Analysis (PCA) or Partial Least Squares Regression (PLS) (see Section 9.4.6) are used for transforming the descriptor set into smaller sets with higher information density. The disadvantage of such methods is that the transformed descriptors may not be directly related to single physical effects or structural features, and the derived models are thus less interpretable. [Pg.490]

In contrast to IR and NMR spectroscopy, the principle of mass spectrometry (MS) is based on decomposition and reactions of organic molecules on theii way from the ion source to the detector. Consequently, structure-MS correlation is basically a matter of relating reactions to the signals in a mass spectrum. The chemical structure information contained in mass spectra is difficult to extract because of the complicated relationships between MS data and chemical structures. The aim of spectra evaluation can be either the identification of a compound or the interpretation of spectral data in order to elucidate the chemical structure [78-80],... [Pg.534]

Any attempt in learning also needs information on situations where the event to be studied will not occur. This principle, if translated to learning on reactions, would require information on reactions that will not proceed. Unfortunately, such information is not contained in reaction databases, and therefore has to he generated. In our case, we also needed information on which regioisomer is not formed, or is formed only to a minor extent, in a pyrazole synthesis. [Pg.545]

Murray-Rust P and H Rzepa 1999. Chemical Markup, XML, and the Worldwide Web. 1. Basic Principles. Journal of Chemical Information and Computer Science 39 923-942. [Pg.45]

For a quantum mechanical calculation, the single point calculation leads to a wave function for the molecular system and considerably more information than just the energy and gradient are available. In principle, any expectation value might be computed. You can get plots of the individual orbitals, the total (or spin) electron density and the electrostatic field around the molecule. You can see the orbital energies in the status line when you plot an orbital. Finally, the log file contains additional information including the dipole moment of the molecule. The level of detail may be controlled by the PrintLevel entry in the chem.ini file. [Pg.301]

The adsorption of a gas by a solid can, in principle, be made to yield valuable information as to the surface area and pore structure of the solid. In practice the range of suitable adsorptives is quite narrow, by far the most commonly used one being nitrogen at its boiling point, 77 K. [Pg.37]

Although there has been some controversy concerning the processes involved in field ionization mass spectrometry, the general principles appear to be understood. Firstly, the ionization process itself produces little excess of vibrational and rotational energy in the ions, and, consequently, fragmentation is limited or nonexistent. This ionization process is one of the mild or soft methods available for producing excellent molecular mass information. The initially formed ions are either simple radical cations or radical anions (M ). [Pg.25]


See other pages where Information Principle is mentioned: [Pg.111]    [Pg.127]    [Pg.3]    [Pg.123]    [Pg.176]    [Pg.1615]    [Pg.238]    [Pg.191]    [Pg.111]    [Pg.127]    [Pg.3]    [Pg.123]    [Pg.176]    [Pg.1615]    [Pg.238]    [Pg.191]    [Pg.67]    [Pg.253]    [Pg.268]    [Pg.516]    [Pg.573]    [Pg.668]    [Pg.27]    [Pg.40]    [Pg.371]    [Pg.76]    [Pg.273]    [Pg.7]    [Pg.522]    [Pg.245]   
See also in sourсe #XX -- [ Pg.196 , Pg.215 ]




SEARCH



Communication Information Principle

Further information 9.3 The Pauli principle

Informed consent principles

Separation Principles (Technique information

© 2024 chempedia.info