MARBI Proposal No. 2008-01: Representation of the Dewey Decimal Classification (DDC) System in MARC 21 formata

The Library of Congress >> Especially for Librarians and Archivists >> Standards

MARC Standards

HOME >> MARC Development >> Proposals List


MARC PROPOSAL NO. 2008-01

02/14/2008 - Results of the MARC Advisory Committee discussion

02/14/2008 - Results of LC/LAC/BL review - Approved.


Proposal Number Contents:

Proposal 2008-01: Representation of the Dewey Decimal Classification (DDC) System in MARC 21 Formats

1. BACKGROUND

1.1 Introduction

Discussion Paper No. 2007-DP06 (Representation of the Dewey Decimal Classification (DDC) System in MARC 21 Formats) was presented to the MARC community in June 2007. This discussion paper was prompted by:

  1. The Dewey editorial team’s converting from a proprietary representation of the DDC into one based on the MARC 21 formats for Classification and Authority data in conjunction with the development of the new Editorial Support System (ESS) at OCLC. In this new system, the record format used for entries in the schedules, tables, and Manual will be based on an enhanced version of the MARC 21 Format for Classification Data, and the record format used for Relative Index (RI) heading records and records for mapped headings from other vocabularies will be based on an enhanced version of the MARC 21 Format for Authority Data. The development team has identified several changes to the Classification and Authority formats to improve the representation of DDC data. Some of these changes are proposed below in section 2 of this discussion paper. Others are likely to be used primarily by DDC editors and translators, and thus will be local additions to the Classification and Authority formats.
  2. The German and Austrian communities’ converting to MARC 21 from the MAB format and needing several changes to the MARC 21 Bibliographic format related to the representation of DDC numbers.

The Dewey editorial team and the team from Deutsche Nationalbibliothek (DNB) worked together on a discussion paper to address improvements to the representation of Dewey information across the MARC 21 formats. This paper was discussed in detail during the MARC Advisory Committee meeting of the ALA Annual Meeting 2007 in Washington, D.C.

This document is a set of proposals arranged in the same order as Discussion Paper No. 2 007-DP06. However, section 2.1 of the Discussion Paper did not lead to a proposal, so the numbering is different. That section suggested adding a subfield $z to field 082 in the Bibliographic format. This is now covered by the proposed new 083 field in the Bibliographic format and thus is no longer required.

1.2 - MARC 21 and DDC

MARC 21 contains provisions for Dewey numbers in all the formats, with the Classification format having the most detailed provision and the Holdings format having the least. Outside of the Classification format and field 083 in the Authority format, the representation is limited to full classification numbers and call numbers. There is little or no support for representation of notation from the external Dewey tables, notation from internal tables or elements of synthesized numbers, and limited information about the type and source of the number. The Bibliographic and Community Information formats represent Dewey numbers in field 082. The Authority format represents Dewey numbers in field 082, which contains a Dewey call number for a series, and field 083, which contains a Dewey classification number associated with the 1XX heading. The Holdings format represents Dewey numbers in the $h subfield (Classification part) of field 852.

The Classification format contains many more details for the representation of Dewey numbers. In particular, it has conventions for the representation of notation in external tables and for ranges of Dewey numbers. Notation in internal tables is represented within the record for the number or span of numbers under which the table appears. Elements of synthesized numbers are documented within the record for the number. The format also provides detailed information about the type and source of numbers

Proposal No. 2008-01/1: Identification of internal add table numbers in the Authority and Classification formats

1. Discussion

This proposal arises from section 2.2 of Discussion Paper 2007-DP06. The DDC includes tables of notation within schedule and table records. These are referred to in this document as "internal add tables." In the current Dewey Editorial Support System (ESS) and in some implementations of the MARC Classification format, internal add tables are represented using a single record for the internal add. In the new ESS, the Dewey editorial team plans to use separate records for each entry in internal add tables. In addition to making it easier to support references to and from notation within add tables, the provision of separate records will support external identification of and access to the notation in internal add tables. The instructions in the MARC Classification format for using separate records for each entry in internal add tables do not work well for the DDC.

The Dewey editorial team recommends using a new subfield $y containing the internal add table number immediately before the subfield containing the add table notation. Subfield $y will have the value 1 for the first internal add table at that location and values 2, 3, etc., for additional internal add tables at the same location. Note that subfield $y was initially defined in the classification format as table name (where the table designation was parsed into table name and table number), but, after experience in implementing the classification format, the subfield was deleted in favor of a combined name/number designation in subfield $z. All existing classification records were changed.

Each subfield $y will be preceded by subfield(s) indicating which schedule or external number record contains the add table, and followed by subfield(s) with the notation within the add table. If either the number of the add table or the notation within the add table is a span, that subfield would be followed by a subfield $c for the number or notation at the end of the span. If the internal add table is inside an external table, then there would be a subfield $z containing the number of the external table.

2. Examples

Here are some examples of subfield $y in the context of the 153 field in the Classification format:

      153 ## $a 290 $y 1 $a 071 $j Education 
             [Dewey notation 071 in the (first and only) internal add table located at 290] 
      153 ## $a 362 $c 363 $y 1 $a 01 $j Philosophy and theory 
             [Dewey notation 01 in the internal add table located under 362-363] 
      153 ## $a 333.7 $c 333.9 $y 1 $a 01 $c 09 $j Standard subdivisions 
             [Dewey notation 01-09 in the internal add table located under 333.7-333.9] 
      153 ## $z 1 $a 08 $y 1 $a 01 $j Forecasting and forecasts 
             [Dewey notation 01 in the internal add table located under Dewey notation 08 in Table 1] 
      153 ## $z 3B $a 1 $c 8 $y 1 $a 901 $c 907 $j Standard subdivisions 
             [Dewey notation 901-907 in the internal add table under Dewey notation 1-8 in Table 3B] 
      153 ## $a 810.1 $c818 $y 2 $a 3 $j 1830-1861 
             [Dewey notation 3 in the second internal add table under 810.1-818]

Here are some examples of subfield $y in the context of the 765 field in the Classification format:

      153 ## $a 346.0469516
      765 0# $b 346.04695 $a 333.7 $c 333.9 $w 333.7 $c 333.9 $y 1 $t 16
      765 1# $b 787.2 $a 784 $c 788 $w 784 $c 788 $y 1 $t 1 $u 787.219369
      765 1# $b 787.21 $a 784 $c 788 $y 1 $v 18 $c 19 $r 784.1 $s 9369 $u 787.219369
      765 1# $b 255.972 $a 255.1 $c 255.7 $w 255.1 $c 255.7 $y 1 $t 06 $u 255.97206

Following is an example of subfield $y for a built number in an internal add table. The built number is found as an example in the add instruction at 0421-0423 in the add table at 616.1-616.9:

Add to base number 042 the numbers following 0 in notation 01-03 from table under 616.1-616.9, e.g., experimental medicine for genetic diseases 04227.

This example involves adding to internal-add-table notation other internal-add-table notation. This would require a record including these fields:

      153 ## $a 616.1 $c 616.9 $y 1 $a 04227
      765 0# $w 616.1 $c 616.9 $y 1 $b 042 $a 616.1 $c 616.9 $y 1 
             $v 0421 $c 0423 $w 616.1 $c 616.9 $y1 $r 0 $t 27 
	     (base notation is 042 in 616.1-616.9 ; instructions found at 
	     0421-0423 in 616.1-616.9; notation 27 is added from 027 in 
	     616.1-616.9)

3. Proposed changes

In the formats and fields listed below, define the following subfield for internal add table notation:

$y – Table number--internal subarrangement or add table (R)

A number or other identifier for an internal classification subarrangement or add table. In the Dewey Decimal Classification it is the number 1 for the first or only add table found at a classification number, and succeeding integers for any following add tables found that that number.

(In Proposals No. 2008-01/5 and No. 2008-01/6 there is the same definition of subfield $y in the proposed 083 and 085 fields in the Bibliographic format; in Proposal No. 2008-01/7 there is the same definition of subfield $y in the proposed 673 and 674 fields in the Classification format.)

Proposal No. 2008-01/2: Revision of field 765 in the Classification format

1. Discussion

This proposal arises from section 2.3 of Discussion Paper 2007-DP06. The Dewey editorial team promised to review field 765 in the Classification format, in light of the extensive use that it was proposing to make of it, in order to identify problems. This proposal arises from that review.

2. Subfield $c in field 765 of the Classification format

Apart from the issue of internal tables addressed in Proposal No. 2008-01/1, one other small problem has been found. In most fields in the Classification format (e.g., fields 761, 763 and 768), the subfield $c is defined as "Classification number--Ending number of span.” The reason is that the first Dewey number in the span can be in various different subfields, having various different meanings.

In field 765, subfield $c is defined as "Number where instructions are found--Ending number of span" because it was assumed that it would only be needed to contain the end of a Dewey number span starting in subfield $a (Number where instructions are found--single number or beginning number of span) or subfield $v (Number in internal subarrangement or add table where instructions are found). The other subfields containing Dewey numbers (e.g., subfield $b Base number, subfield $r Root number, and the subfield $u Number being analyzed) could not refer to spans.

However, when analyzing numbers involving internal add table notation, we found that subfield $w (Table identification--internal subarrangement or add table) might need to be used in conjunction with subfield $c. An example is in notation 0425-0429 in the add table at 616.1-616.9, which has this instruction:

Add to base number 042 the numbers following 0 in notation 05-09 from table under 616.1-616.9, e.g., therapy for genetic diseases 0426, gene therapy 042695.

In the new Dewey Editorial Support System, we propose creating a record for every number used as an example, so the record for the example of 042695 would need to include these fields:

      153 ## $a 616.1 $c 616.9 $y 1 $a 042695 
      765 0# $w 616.1 $c 616.9 $y 1 $b 042 $w 616.1 $c 616.9 $y 1 $v 0425 $c 0429 $w 616.1 
	     $c 616.9 $y 1 $r 0 $s 6
      765 0# $w 616.1 $c 616.9 $y 1 $b 0426 $w 616.1 $c 616.9 $y 1 $v 062 $c 069 $r 615.8 $s 95

We propose that subfield $c be renamed as "Classification number--Ending number of span" to reflect the fact that it can be needed in a situation like this.

3. Proposed changes

In field 765 in the Classification format, redefine subfield $c as:

$c - Classification number--Ending number of span (R)

(In Proposal No. 2008-01/6, there is the same definition of the $c subfield in the proposed 085 field in the Bibliographic format.)

Proposal No. 2008-01/3: Classification number edition and source information in the Bibliographic and Classification format

1. Discussion

This proposal arises from section 2.4 of Discussion Paper 2007-DP06. MARC Discussion Paper No. 2007-DP06 proposed that the Dewey editorial team develop and maintain a registry of edition identifiers in which each edition would have a standard representation in subfield $2 and that the assigning agency of the Dewey number be coded in a new $5 subfield of the 082 field in the Bibliographic format and of the 084 field of the Classification format, e.g.:

082 04 $a 004 $2 22/ger $5 DE-101b

There is strong interest from libraries outside the United States in knowing whether DDC numbers have been assigned by their national library, just as American libraries are interested in knowing whether DDC numbers have been assigned by the Library of Congress. Currently the second indicator in field 082 specifies whether the Library of Congress (value 0) or another agency (value 4) has assigned the classification number, but there is no mechanism to specify which agency.

At the MARBI meeting at the 2007 ALA Annual Conference there was some concern that using subfield $5 for assigning agency did not correspond with its definition (Institution to which field applies). Therefore this proposal suggests that a new subfield $q be used for the purpose. Subfield $q is suggested because it is not currently used in fields 05X-08X of the Bibliographic format, fields 05X-08X of the Authority format, the 01X-08X block of the Classification format, or field 765 in the Classification format. Thus the example given above would become:

082 04 $a 004 $2 22/ger $q DE-101b

Subfield $q is only used when the second indicator is 4 (Assigned by agency other than LC). Subfield $q contains the MARC code of the institution that assigned the Dewey number.

2. Proposed changes

In the field 082 (Dewey Decimal Classification Number) of the MARC 21 Bibliographic Format and field 084 (Classification Scheme and Edition) of the MARC 21 Classification Format add:

$q - Assigning agency (NR)
Subfield $q contains the MARC code of the institution that assigned the Dewey number.

(In Proposal No. 2008-01/5 below there is the same definition of subfield $q in the proposed 083 field in the Bibliographic format.)

Proposal No. 2008-01/4: Designations for optional numbers in the Bibliographic format

1. Discussion

This proposal arises from section 2.5 of Discussion Paper 2007-DP06.

Field 082 in the Bibliographic format can contain more than one Dewey number, and can contain optional numbers as well as standard numbers. A standard Dewey number is defined as the single number that would have been assigned using the instructions in the edition cited in subfield $2. An optional number is a Dewey number listed in parentheses in the schedules or tables that is an alternative to standard notation, or a Dewey number constructed by following an option. For example:

       082 00 $a 345.73/0772 $a 347.305772 $2 20 
              [345.73/0772 is the standard Dewey number for sentencing in 
	      US criminal law, and 347.305772 is an optional number]

       082 04 $a A824.308 $2 22
              [Here an optional letter "A" for Australian literature in English has 
	      been inserted before the literature number, and an optional digit 3 has been 
	      used for the literary period.]

The Dewey editorial team proposes the addition of subfield $m in field 082 in the Bibliographic format to indicate the nature of the number in subfield $a in relation to the edition cited in subfield $2. It would be specified as follows:

       $m  Standard or optional designation
              Indicates whether the classification number contained in the field is 
	      from the standard or optional part of the schedules or tables of 
	      the scheme identified by the first indicator (Type of edition) 
	      and by subfield $2 (Edition number).
                 a - standard
                 b - optional

In cases where the subfield is used, it assumes that there is only one Dewey number in field 082. If both a standard Dewey number and one or more optional numbers are given to a work, field 082 must be repeated. Legacy data with more than one Dewey number in field 082 would have no information about the numbers: in many cases the field will contain one or more standard numbers and one or more optional numbers. Legacy data with only one Dewey number in the field might involve an optional number, especially for options used by national libraries outside the United States.

With data created in the future, in the absence of subfield $m, it is assumed that the Dewey number was intended to be a standard number.

2. Examples

      082 00 $a 345.73/0772 $2 20 $m a
      082 00 $a 347.305772 $2 20 $m b 
      082 00 $a 824/.914080994 $2 22 $m a 
      082 04 $a A824.308 $2 22 $m b

3. Proposed changes

In field 082 in the Bibliographic format, add the following:

      $m - Standard or optional designation (NR)
      Indicates whether the classification number contained in the field is from 
      the standard or optional part of the schedules or tables of the scheme identified 
      by the first indicator (Type of edition) and by subfield $2 (Edition number). 
      A standard Dewey number is defined as the single number that would have been 
      assigned using the instructions in the edition cited in subfield $2.  
      An optional number is a Dewey number listed in parentheses in the schedules 
      or tables that is an alternative to standard notation, or a Dewey 
      number constructed by following an option.
         a - standard
         b - optional

(In Proposal No. 2008-01/5 below there is the same definition of subfield $m in the proposed field 083 in the Bibliographic format.)

Proposal No. 2008-01/5: Additional Dewey numbers for access in the Bibliographic format

1. Discussion

This proposal arises from section 2.6 of Discussion Paper 2007-DP06. The previous MARBI meeting resulted in a suggestion to look at what would need to be done in the proposed field 085 to include both Dewey numbers provided for subject access and analysis of Dewey numbers found in 082 fields. Using one field for both would require an indicator to code whether the number given is for subject access or to analyze a Dewey number in an 082 field. If the number given is being used for access, then many of the subfields used in field 765 become irrelevant; however, we still need to identify which subfield to use for the access number. There are problems with dual use of the 085 field, including the problem that many subfields would be valid only with certain indicator values, and the problem of exactly how to represent an internal table number used for access in the 085 field.

Consequently it is proposed that a new field 083 be defined in the Bibliographic format for Dewey numbers, including internal and external table numbers, used for subject access. This field (Dewey Decimal Access Number) will have the same indicators and subfields as used and proposed for field 082, with the addition of subfields $c, $y, and $z, which would not be used in field 082, since that is the primary Dewey number. Definitions of the subfields will be the same as in field 082 (including the proposed $m and $q).

Field 082 in the Bibliographic format is not affected by this proposal. I t would continue to be used for the primary Dewey number assigned using the rules given in the DDC schedules and tables, so that libraries using field 082 to create local call numbers could continue to do so in the same way. Only institutions wanting to use Dewey numbers for additional subject access will be affected by this proposal.

2. Examples

      082 04 $a 388.13 $2 22
      083 0# $z 2 $a 4947 $2 22
             [For a book on tunnels in the Swiss Alps. The Dewey number 388.13 is 
	     used for interdisciplinary works on tunnels, but the number itself is 
	     broader, covering a variety of special road features.  Consequently, 
	     geographic area notation cannot be added to the primary number in field 
	     082. Field 083 contains the geographic area notation from Table 2 for 
	     the Swiss Alps.] 
      082 04 $a 599.0994 $2 22
      083 0# $a 598.0994 $2 22
      083 0# $z 2 $a 94 $2 22
             [For a book on Australian birds and mammals. The Dewey number 
	     599 is used for works on mammals and for comprehensive works on 
	     birds and mammals.  The rest of the primary number in field 082 
	     consists of 09 Geographic treatment from Table 1 and 94 Australia 
	     from Table 2.  There is no way to tell from this number whether 
	     the book contains information about birds or not. The Dewey number 
	     598 in the first 083 field means birds, and the full number means
	     birds in Australia.  The second 083 field has the Table 2 area 
	     number for Australia; it is intended to help users seeking 
	     everything about Australia.]

3. Proposed changes

Define the following new field and subfields in the Bibliographic format:

Proposal No. 2008-01/6: Synthesized classification number components in the Bibliographic format

1. Discussion

This proposal arises from section 2.6 of Discussion Paper 2007-DP06. As described in Proposal No. 2008-01/5 above, this paper proposes using separate fields for Dewey numbers provided for subject access and analysis of Dewey numbers found in 082 fields. This the paper proposes the definition of a new field 085 in the Bibliographic format limited to the same purpose as field 765 in the Classification format, i.e., to analyze synthesized classification numbers in other fields. Either a Dewey number in field 082 or one in the proposed field 083 may be analyzed, with subfield $8 providing a link between the related fields.

2. Examples

      082 00 $8 1 $a 346.0469516 $2 22 
      085 0# $8 1.1 $b 346.046 $a 346.046 $r 333 $s 95
      085 0# $8 1.2 $b 346.04695 $a 333.7 $c 333.9 $w 333.7 $c 333.9 $t 16
             [The Dewey number in the 082 field--346.0469516--means law providing for 
	     government control and regulation of biological resources for the sake 
	     of conserving them.  The first 085 field shows that the number 346.04695 
	     was built with 346.046 Law of government control and regulation of specific 
	     kinds of natural resources plus 95 from 333.95 Biological resources, 
	     following the instructions at 346.046.  The second 085 field shows that 
	     the number 346.0469516 was built with 346.04695 plus 16 Conservation from 
	     the first add table under 333.7-333.9, as instructed under 333.7-333.9.] 
     082 04 $8 1 $a 599.0994 $2 22
     083 0# $8 2 $a 598.0994 $2 22
     085 0# $8 1.1 $b 599 $z 1 $s 09
     085 0# $8 1.2 $b 599.09 $z 1 $a 093 $c 099 $z 2 $s 94
     085 0# $8 2.1 $b 598 $z 1 $s 09
     085 0# $8 2.2 $b 598.09 $z 1 $a 093 $c 099 $z 2 $s 94
            [The first two 085 fields show how the Dewey number in the 082 field – 
	    599.0994 – was built.  The first 085 field shows that 599.09 was 
	    built with 599 Mammals plus 09 Geographic treatment from Table 1 
	    Standard subdivisions.  The second 085 field shows that 599.0994 
	    was built with 599.09 plus 94 Australia from Table 2 Areas, 
	    following instructions at 093-099 in Table 1.  The second t
	    wo 085 fields show how the Dewey number in the 083 field – 598.0994
	    – was built.]

3. Proposed changes

Define the following new field and subfields in the Bibliographic format:

Proposal No. 2008-01/7: Segmentation information in the Classification format

1. Discussion

This proposal arises from section 2.7 of Discussion Paper 2007-DP06. In the present Dewey Editorial Support System, seg and set fields are used for segmentation information. The seg field is used for records for a single Dewey number or number span to show where the segmentation mark appears. The set field is used for Dewey number records that contain number-building instructions to give segmentation information that cannot be expressed using a single number or number span. Segmentation is the indication of logical breaks in a number by a typographical device, represented by a slash (/) in MARC. Prior to September 2005, segmentation marks might indicate the end of an abridged number or the beginning of a standard subdivision. Since then, LC has been giving only one segmentation mark, to indicate the end of an abridged number.

New fields 673 and 674 in the Classification format are proposed for segmentation information, to encode seg and set fields, respectively. Such information is already shared data with segmentation marks in field 082 of Bibliographic records, and it is considered to be of equal interest in Classification records.

2. Examples

      673 ## $a 025.4/31
      674 ## $i Segment as shown in $a 599.2 $c 599.8 $i , e.g., $a 636.9205 $i, 
	     $a 636.92/9 $i , $a 636.935/6

3. Proposed changes

Define the following in the Classification format:

Proposal No. 2008-01/8: Encoding topic information in some Classification format fields

1. Discussion

This proposal arises from section 2.8 of Discussion Paper 2007-DP06. The Dewey editorial team wishes to use subfield $t for topics named in examples in fields 680, 683, and 761. Subfield $t is already used for this purpose in fields 453, 553, and 768.

Subfield $t is needed to distinguish topical information from "canned text" (canned text being text that remains the same for particular kinds of fields, regardless of topic), and to enable automated identification of the meaning of DDC numbers given in examples. The topical information in subfield $t could be made searchable in an index along with other terms.

Note that the use of these fields is not limited to the DDC, and that other classification schemes such as the Library of Congress Classification may want to consider using this subfield code.

2. Examples

      680 1# $i An area is classed in its present number even if it had a different affiliation 
                at the time under consideration, e.g., $t Arizona under Mexican sovereignty 
		$z 2 $a 791 $i (not $z 2 $a 72)
      683 0# $i In building numbers, do not add by use of 0 or 1 (alone or in combination) 
                 more than twice, e.g., $t history of rock protest songs $a 782.421661592 $i 
                (not $a 782.42166159209)
      761 #0 $i Add to base number $b 025.29 $i notation $z 2 $d 1 $c 9 $i from Table 2, 
                e.g., $t acquisition of materials from Latin America $e 025.298

3. Proposed changes

Add subfield $t - Topic used as example (R), to the following fields in the Classification format:

Proposal No. 2008-01/9: Classification number hierarchy

1. Discussion

This proposal arises from section 2.9 of Discussion Paper 2007-DP06. Currently in field 153 of the Classification format only the upward caption hierarchy is given, in subfields $h and $k. The classification numbers associated with those captions are not given. An example, using the DDC number 616.5, is:

      153 ## $a 616.5 $h Technology (Applied sciences) $h Medicine and health $h Diseases 
      $k Specific diseases $k Diseases of specific systems and organs $j Diseases of integument 

The Dewey editorial team recommends using a new subfield $e (Classification number hierarchy--single number or beginning of a span) in field 153 to link to the next number or number span upwards in the classification number hierarchy. This will provide the link to the appropriate headings and the appropriate notes with hierarchical force. It will also indirectly provide for links to the downward hierarchy.

This is intended to be used in any classification scheme, such as DDC or UDC, where hierarchy is expressed by the notation. Particular MARC representations of particular classification schemes might use either subfield $e, or subfields $h and $k, or both, in storing and distributing classification records.

2. Examples

      153 ## $a 616.1 $c 616.9 $j Specific diseases $e 616
             [Span 616.1-616.9 is under number 616]
      153 ## $a 616.1 $c 616.8 $j Diseases of specific systems and organs $e 616.1 $c 616.9   
             [Span 616.1-616.8 is under span 616.1-616.9]
      153 ## $a 616.5 $j Diseases of integument $e 616.1 $c 616.8 
             [Number 616.5 is under span 616.1-616.8]
      153 ## $z 2 $a 73 $j United States $z 2 $c 7 
             [Notation 73 in Table 2 is under notation 7]

3. Proposed changes

Add subfield $e - Classification number hierarchy--single number or beginning number of span (NR), to field 153 (Classification Number ) in the Classification Format.

.

Appendix: Field 082 in the Bibliographic format and field 153 in the Classification format

Since field 082 in the Bibliographic format and field 153 in the Classification format are referred to many times in this proposal, this appendix gives a summary of these fields, including the proposed changes (which are marked as "Proposed").

.

Bibliographic format

Classification format


HOME >> MARC Development >> Proposals List

The Library of Congress >> Especially for Librarians and Archivists >> Standards
( 12/21/2010 )
Legal | External Link Disclaimer Contact Us