Database definition

In order to define an accident database, we have to specify the types of facts or data elements to be included in each accident or near-accident record. We also have to specify a data type for each element. This tells us whether the data is coded according to a nominal, ordinal, interval or ratio scale or stored in free text. Both these specifications are included in the so-called database definition. Each data element and its associated data-type specification are 

1 The amount and quality of the required information, as defined by the accident model and 

2 The time and attention needed for investigations and quality assurance of the results before storage in the database. 

In Chapter 6, we discussed problems that the investigator faces when applying a complex accident causal model in the collection of data on accidents. A careful balance has to be made between the amount of information required, the quality of the information, and the time needed for the investigation. This balance is problematic, since the benefits of detailed information of a high quality are usually experienced by another part of the organisation than those responsible for the collection of the data. They have first-hand experience anyway. 

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Benichou, C., Danan, G. and Solal-Celignz, P. (1991). Standardization of international databases Definitions of drug-induced blood cytopenias. Int. J. Clin. Pharmacol. Toxicol. 29 75-81. 

With prototyping, the screen layout and look and feel of the screens can be quickly built to confirm that the system is fulfilling expectations. Screen input, range checks, and display requirements can also be clarified along with the database definition. 

The search criteria are determined by the database definition. There are three basically different principles for searches in the database ... 

For the containment the natural discretisation is into interconnected subcompartments (unless a fully three-dimensional treatment is envisaged), as a discussion between experts on CONTAIN and JERICHO emphasised. Each volume may then have sub-databases describing the walls, internal structures, sump, and atmosphere. This last will have its own database including thermal-hydraulic variables plus an aerosols database and so on. The details will become clearer as code integration proceeds, but the overall philosophy is clear. The description for all systems (core, circuit, containment) is to be in terms of volumes, with a well-defined and natural tree structure being imposed on the data describing each volume. Database definitions are now available for the core/bundle, circuit and containment (including iodine chemistry), and are underdevelopment for core-concrete interaction. 

This database provides thermophysical property data (phase equilibrium data, critical data, transport properties, surface tensions, electrolyte data) for about 21 000 pure compounds and 101 000 mixtures. DETHERM, with its 4.2 million data sets, is produced by Dechema, FIZ Chcmic (Berlin, Germany) and DDBST GmhH (Oldenburg. Germany). Definitions of the more than SOO properties available in the database can be found in NUMERIGUIDE (sec Section 5.18). 

Reactions can be considered as composite systems containing reactant and product molecules, as well as reaction sites. The similarity of chemical structures is defined by generalized reaction types and by gross structural features. The similarity of reactions can be defined by physicochemical parameters of the atoms and bonds at the reaction site. These definitions provide criteria for searching reaction databases [23],... 

To decide which molecule to add at each iteration requires the dissimilarity values between each molecule remaining in the database and those already placed into the subset to be calculated. Again, this can be achieved in several ways. Snarey et al. investigated two conunon definitions, MaxSum and MaxMin. If there are m molecules in the subset then... 

Definitive proof of the structure of porphine in the solid state awaits a variable-temperature crystallographic (X-ray or neutron diffraction) study the analysis of the anisotropic displacement factors (ADP) should disclose any rotational motion or its absence as well as determine the positions of the inner hydrogens. A search in the September 1998 version of the Cambridge Structural Database [CSD (91MI187)] showed that the only structures of porphine (codename PORPIN) were obtained in 1965 and 1972. 

Figure 6. A porHon of the database for vinylidene chloride isobutylene copolymer. Boxed entries are required input from the user. The peak definition for the first peak is shown.

The major advantage of the tandem mass spectrometry approach compared to MALDI peptide fingerprinting, is that the sequence information obtained from the peptides is more specific for the identification of a protein than simply determining the mass of the peptides. This permits a search of expressed sequence tag nucleotide databases to discover new human genes based upon identification of the protein. This is a useful approach because, by definition, the genes identified actually express a protein. 

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