Open Source Software for Digital Preservation Repositories: a Survey <s> Main standardsand protocols <s> Encoded Archival Description (EAD) is an emerging standard used internationally in an increasing number of archives and manuscripts libraries to encode data describing corporate records and personal papers. The individual descriptions are variously called finding aids, guides, handlists, or catalogues. While archival description shares many objectives with bibliographic description, it differs from it in several essential ways. From its inception, EAD was based on Standard Generalized Markup Language (SGML), and, with the release of EAD version 1.0 in 1998, it is also compliant with EXtensible Markup Language (XML). EAD was and continues to be developed by the archival community. While development was initiated in the United States, international interest and contribution are increasing. EAD is currently administered and maintained jointly by the Society of American Archivists and the United States Library of Congress. Developers are currently exploring ways to internationalize the administration and maintenance of EAD to reflect and represent the expanding base of users. ::: ESARBICA Journal Vol.20 2001: 71-80 <s> BIB001 </s> Open Source Software for Digital Preservation Repositories: a Survey <s> Main standardsand protocols <s> Abstract An increasing number of libraries that receive materials using Internet document delivery (IDD) systems are creating electronic document delivery services to redirect those materials directly to their customers. While academic libraries have embraced IDD and electronic document delivery systems, hospital libraries have faced significant barriers which often prevent them from implementing such services. The docMD project has been created to investigate the use of a centralized document mediation center as a method of overcoming these barriers. During the eighteen-month project timeline a centralized center will be established that will receive documents intended for project libraries and that are sent using an Ariel compatible IDD system. The documents will be converted to the Portable Document Format (PDF) and delivered directly to their requestors using the Web. docMD is a project of the John A. Prior Health Sciences Library at the Ohio State University with assistance from the Cleveland Library... <s> BIB002 </s> Open Source Software for Digital Preservation Repositories: a Survey <s> Main standardsand protocols <s> Motivated by preservation and resource discovery, we examine how digital resources, and not just metadata about resources, can be harvested using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). We review and critique existing techniques for identifying and gathering digital resources using metadata harvested through the OAI-PMH. We introduce an alternative solution that builds on the introduction of complex object formats that provide a more accurate way to describe digital resources. We argue that the use of complex object formats as OAI-PMH metadata formats results in a reliable and attractive approach for incremental harvesting of resources using the OAI-PMH. <s> BIB003 </s> Open Source Software for Digital Preservation Repositories: a Survey <s> Main standardsand protocols <s> At the core of the MPEG-21 Multimedia Framework is the concept of the Digital Item, a virtual container for a hierarchical structure of metadata and resources. This paper considers the Digital Item Declaration Language (DIDL), gives examples of its usage, and discusses how it is used to integrate other parts of MPEG-21. The paper then discusses how Digital Item Identification integrates with the DIDL to allow MPEG-21 to utilize standard identifiers from many application spaces. Finally, an alternative, compressed form of the XML Digital Item Declaration is described. This uses schema-based compression to significantly reduce the size of these XML documents. <s> BIB004 </s> Open Source Software for Digital Preservation Repositories: a Survey <s> Main standardsand protocols <s> In 2003 the Online Computer Library Center (OCLC) and Research Libraries Group (RLG) established an international working group to develop a common, implementable core set of metadata elements for digital preservation. Most published specifications for preservation-related metadata are either implementation specific or broadly theoretical. PREMIS (Preservation Metadata: Implementation Strategies) was charged to define a set of semantic units that are implementation independent, practically oriented, and likely to be needed by most preservation repositories. The semantic units will be represented in a data dictionary and in a METS-compatible XML (eXtensible Markup Language) schema. In the course of this work, the group also developed a glossary of terms and concepts, a data model, and a typology of relationships. Existing preservation repositories were surveyed about their architectural models and metadata practices, and some attempt was made to identify best practices. This article outlines the history and methods of the PREMIS Working Group and describes its deliverables. It explains major assumptions and decisions made by the group and examines some of the more difficult issues encountered. <s> BIB005 </s> Open Source Software for Digital Preservation Repositories: a Survey <s> Main standardsand protocols <s> An actuating system for accelerator comprising: a main body comprising a motor for driving said accuating system, a reduction gear including a means for locking connected to an output shaft of said motor, and a pulley for winding or supplying a cable, said pulley having an internal gear engaged with a gear provided on said output shaft; a control cable comprising a tubular conduit and an inner cable which is slidably inserted into said conduit, wherein an end portion for driving said pulley of said inner cable is wound by said pulley; a bracket for fixing said main body to a car body, wherein said pulley is rotatably carried by said bracket, wherein said bracket is connected to an end part of said conduit; a casing in which said body and a means for controlling said main body are enclosed together with said bracket in a manner that an elastic body is interposed between said main body and said bracket, wherein an opening for directing said cable is formed on said casing, wherein said opening retains a part of said control cable in a manner that an elastic body is interposed between a periphery of said opening and said control cable; and a means for connecting said control cable to a controlled device wherein said means is formed on a driven-side end of said control cable. <s> BIB006
Two main protocols for interoperability are the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) BIB003 and the Search/Retrieval via URL (SRU)  . OAI-PMHwas created by the Open Archives Initiative for repository interoperability. It consists of six verbs or services invoked over HTTP. The verbs/services are: i) GetRecord; ii) Identify; iii) ListIdentifiers; iv) ListMetadataFormats; v) ListRecords; vi) ListSets BIB003 .The repositories can act as data providers, exposing structured data through the protocol or as service consumers making requests through the protocol to harvest metadata from the providers.SRU is a XML-based protocol to allow search queries over the internet. It uses the Contextual Query Language (CQL) standard  , a syntax for representing queries to retrieve data from the repository and exposesthem in a structured form through XML. Metadata standards define the main characteristics needed to describe digital objects, such as, videos, sounds, images, texts and web sites. The main standards are Dublin Core  , PREservation Metadata Implementation Strategies (PREMIS) BIB005 , Machine Readable Cataloguing (MARC)  , Encoded Archival Description (EAD) BIB001 , Metadata Encoding and Transmission Standard (METS)  and the Metadata Object Description Schema (MODS)  . The Dublin Core standard was created in 1995 and is maintained by the Dublin Core Metadata Initiative. It comprises 15 properties with metadata vocabularies and technical specifications, which can describe a wide range of resources  . PREMIS, MARC, EAD and METS are all XML-based standards. PREMIS, developed by the Online Computer Library Center (OCLC) and Research Libraries Group (RLG), consists of a data dictionary, an XML schema and supporting documentation. MARC was developed by the American Library of Congress for cataloguing digital objects stored in a repository. METS isa part of MARCfor encoding descriptive, administrative and structural metadata about digital objects within a repository. MARC21 is the most recent version, while MARCXML is an extension of MARC21 with additional features for sharing and networked access of bibliographical information  . MODS is another MARC21 compatible XML for descriptive metadata. EAD is a descriptive XML-based standard aimed at describing the hierarchy structure of archival data. It bears some similarity with MARC, although EAD focuses on archives, while MARC is oriented towards bibliographical materials BIB001 . Others, more specific, standards and protocols considered in this paper are the Digital Item Declaration Language (DIDL) BIB004 for video content, the Metadata for Images in XML (MIX)  for still images, the Technical Metadata for Text (TextMD) BIB006 for text, the Advanced Encryption Standard (AES)  for encryption, the Document Mediated Delivery (DocMD) BIB002 , AudioMD for audio  , and VideoMD for video  .It is important to note that regarding metadata standards, there is no consensus about which ones are the most important. As such, this study presents the ones implemented by each reviewed system.