Modul 4 Struktur Informasi Mata Kuliah Preservasi Informasi Digital.
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Transcript of Modul 4 Struktur Informasi Mata Kuliah Preservasi Informasi Digital.
Modul 4Modul 4Struktur InformasiStruktur Informasi
Mata Kuliah Preservasi Informasi Digital
Outline
Skema Pengumpulan DokumenSkema DokumentasiModel Obyek Digital
Catatan: sumber bacaan Bab 6 [GHM]
Introduction
Preservation method represent whatever authors wants to express (within the limit of what language can express)
The need of data model Simple and also able to model all practical information structures
Terminologies A blob (binary large object) is a closely associated agglomeration of
data that is managed as a single entity. The term ‘blob’ is used to signal that neither the blob’s meaning nor its internal structure is relevant within the discussion at hand.
A bit-string is a linearized form of a blob suitable for sending over a simple communication channel.
A file or dataset is a blob’s storage form, in which the content might be represented in noncontiguous segments on a magnetic or optical storage volume or on a set of storage volumes.
The storage layout is chosen and managed by a file system in order to provide better reliability, economy, performance, and flexibility than is likely to be provided by a simple, contiguous layout.
A file system usually includes a programming interface to provide any file in bit-string format.
Syntax Specifications
String Syntax Definitions with Regular Expression Regular expressions:
• Context-independent syntax• Pattern – select specific strings from a set of character strings• Automata theory & formal language theory models of computation & ways
to describe and classify formal language
BNF (Backus-Naur Form) formal language for defining the grammar of a context-free language
• The Extended Backus-Naur Form (EBNF) adds the syntax of regular expressions to the BNF notation in order to allow very compact specifications
Each rule of a BNF grammar has the form: symbol ::= expression.• symbol if defined by regular expression: initial capital, lower case, • expression right-hand side of rule which has the syntax shown below to
match strings of one or more characters
Syntax Specifications
The Abstract Syntax Notation (ASN.1) used to express syntax of objects and messages Basic Encoding Rules (BERs) enable abstract data value specifications to be
represented in concrete form as an array of bytes ASN.1 DER (Distinguished Encoding Rules) and BER-encoded data is largely
platform-independent, helping to make the byte-stream representation of a standards definitions document that uses it easy to transport between computers on open networks
widely used to describe security protocols, interfaces, and service definitions, such as the X.500 Directory and X.400 Messaging systems, which include extensive security models. An example of language specification to aid the specification of security mechanisms occurred during the specification of the Secure Electronic Transaction (SET) standard.
Syntax Specifications
XML Schema define the record structure for any data type of interest, and are
particularly prominent in the use of XML to package information of various data types.
Typically a schema is expressed as a set of properties with an associated type. For instance, an informational schema description for a customer database would be something like: (1) Name: string of up to 80 characters; (2) Customer ID: number of up to 10 digits; (3) Orders: a list of Order records
Collections
Property of a library A documents that tabulates or
otherwise identifies the collection members traditional library catalog
In digital library? almost every document defines a collection— the set of documents and other objects that it references
Digital Object Schema
Payload content Metadata blobs provided by information providers
(authors, editor, artist, etc.) Relationships & Relation Names and Identifiers, References, Pointers, and Links Value Sets
Metadata
Structured data about other data In digital collections, metadata fulfill a variety of tasks, including
identifying items uniquely worldwide; describing collection items (e.g., author, creation date), including their contexts; supporting retrieval and identification; grouping items into collections within a repository; recording authenticity evidence, including historical audit trails; helping protect item integrity against improper change and unintentional
corruption; recording access permissions and other digital rights information; facilitating information interchange between autonomous repositories; and recording technical parameters describing items’ representations.