Support : Dialog Search Aids : Using Derwent Classification to Improve Subject Searching

Using Derwent Classification to Improve Subject Searching

One or more Derwent Classes are applied to all Derwent World Patents Index (Files 350/351/352) database records, and these classes have a multitude of uses in searching. You can, for instance, use them to cover a large subject area very quickly — for example, the whole of footwear can be covered with Derwent Class code "P22" without having to think of all the words that could possibly describe footwear (e.g. shoes, boots, soles, etc.). Another application of Derwent Classes is to provide the context for words that have multiple meanings across subject areas.

The search in Figure 2 is a good example of how Derwent Classes can be used to overcome the problem of ambiguous search terms. It is a search for patents on antilock braking systems (ABS) for cars and other vehicles while excluding patents on ABS, the acrylonitrile-butadiene-styrene polymer.

Any of the Derwent files can be used with Derwent Classes. Use File 350, 351, or 352, depending on your subscription level or geographic location. First, search all variations of the search terms for antilock brakes. Next, TYPE out some results to make sure of the relevance of the search. Note that this record is about ABS, the polymer.

Now, use the Derwent Classification code, DC=Q18, to restrict retrieval to brake-control systems. Display the search results using the TYPE (T) command. Format 28 is one of the preview formats.

This search example illustrates the value of using Derwent Classes to restrict a search simply and effectively to a specific subject area.

?BEGIN 351

File 351:Derwent WPI  1963-2001/UD,UM &UP=200117
       (c) 2001 DERWENT INFO LTD


?SELECT ABS OR (ANTILOCK? OR ANTI(W)LOCK?)(W)BRAK?
           13945  ABS
            2195  ANTILOCK?
          168913  ANTI
          292673  LOCK?
            2767  ANTI(W)LOCK?
          120999  BRAK?
            2960  (ANTILOCK? OR ANTI(W)LOCK?)(W)BRAK?
      S1   16230  ABS OR (ANTILOCK? OR 
                   ANTI(W)LOCK?)(W)BRAK?

?TYPE S1/26

  1/26/1 
DIALOG(R)File 351:Derwent WPI
(c) 2001 DERWENT INFO LTD. All rts. reserv.

013577140
WPI Acc No: 2001-061347/200107
 Polymerisation of diene in vinyl-aromatic
 monomer to give rubber for production of 
 impact polystyrene and ABS, carried out 
 with Group 4, 5 or 6 transition metal 
 chelate catalyst and a Lewis acid cocatalyst 
 


?SELECT S1 AND DC=Q18
           16230  S1
           33492  DC=Q18  (Brake control systems)
      S3    3303  S1 AND DC=Q18
	  
?TYPE S2/28/1

  2/28/1 
DIALOG(R)File 351:Derwent WPI
(c) 2001 DERWENT INFO LTD. All rts. reserv.

013575942    **Image available**
WPI Acc No: 2001-060149/200107
XRPX Acc No: N01-044964
 Brake pump activation method for vehicles,
 involves activating brake pump when difference
 between desired and actual fill states of low
 pressure accumulator exceeds specific amount 
Number of Countries: 001  Number of Patents: 001
Title Terms: BRAKE; PUMP; ACTIVATE; METHOD; 
  VEHICLE; ACTIVATE; BRAKE; PUMP; DIFFER; ACTUAL;
  FILL; STATE; LOW; PRESSURE; ACCUMULATOR; SPECIFIC;
  AMOUNT
Derwent Class: Q18; X22
International Patent Class (Main): B60T-013/68
File Segment: EPI; EngPI
Manual Codes (EPI/S-X): X22-C02C1; X22-C02C3