Uwe M. Borghoff

A Theory for Model-Based Transformation Applied to Computer-Supported Preservation in Digital Archives

Model transformation has applications in many areas as, e.g., in model-driven software development or automated knowledge exchange. When applied, model transformations usually have in common that the transformation process shall preserve certain properties. In model-driven software development, e.g., abstract models are transformed into more specific ones while preserving the behavior of the specified software system. In this paper, we present a model transformation approach that implements a preservation-centric view. We introduce a formal preservation language that allows transformation algorithms to be computed automatically. Additionally, these generated transformations can be proven to respect specified preservation requirements. We demonstrate our approach using a systems specification example that stems from the digital archiving world. We specify a Web-archiving system that consists of two components each of which uses its own Website model for storage. Internal processes necessitate exchanging Websites between these two components and, thus, model transformation. We apply our preservation language and show how the algorithm generation procedure generates a transformation algorithm that guarantees an unchanged external view on the transformed Websites

Preservation of digital publications: an OAIS extension and implementation

Over the last decades, the amount of digital documents has increased exponentially. Nevertheless, traditional document engineering methods are applied. Even worse, the long-term preservation issues have been neglected in standard document life cycle implementations.Our digital (cultural) heritage is, therefore, highly endangered by the silent obsolescence of data formats, software and hardware. Severe losses of information already happened. It is high time to implement concrete solutions.Fortunately numerous institutions already target these issues. Moreover, with the OAIS reference model1 a rich standardized conceptual framework is available, which already serves as implementation basis.2This paper discusses an extension to the OAIS reference model and illustrates a prototype implementation of a document life cycle that is enriched by functions for long-term preservation.More precisely, this paper aims to provide first solutions to the following three problem areas:1. Detachment: OAIS defines no functions for the process of detaching digital documents prior to the ingest function. This detachment function is modeled in great detail and implemented for the provision of the so-called OAISs submission information packages (SIP).2. DBMS: OAIS defines a very complex functionality. We show how a standard database management system (DBMS) can support a wide variety of required functionalities in an integrated and homogenous way. Among others OAISs data management, archival storage, and access are supported.3. Metadata: So far, OAIS does not cover any aspects of the metadata generation. Here, we briefly discuss the (semi-)automatic generation of a metadata set.In order to evaluate the feasibility of our approach, we built a first prototype. We carried out our experiments in close cooperation with the Bavarian State Library, Munich, which is engaged in numerous international initiatives dealing with the problem of long-term preservation. Our University Library also supported us by delivering a representative test set of digital publications.3We conclude our paper by presenting some lessons learned from our conceptual work and from our real world experiments.

The Use of Quality Management Standards in Trustworthy Digital Archives

Quality management is an essential part in creating a trustworthy digital archive. The German network of expertise in Digital long-term preservation (nestor), in cooperation with the German Institute for Standards (DIN), has undertaken a small study to analyse systematically the relevance and usage of quality management standards for long-term preservation and to filter out the specific standardisation need for digital archives. This paper summarises the results of the study. It gives an overview on the differences in understanding the task “quality management” within different organisations and how they carry out appropriate measures, such as documentation, transparency, adequacy, and measureability in order to demonstrate the trustworthiness of their digital archive.

Preservation-centric and constraint-based migration of digital documents

We introduce a framework that supports archivists in planning and running migrations. The central idea is that -once relevant information pieces of digital documents are modeled -desired migration results can be specified by means of preservation constraints. From these constraint specifications we are able to derive migration algorithms that provably respect a set of document properties before (pre-conditions) and after migration (post-conditions). Underlying is the concept of Abstract State Machines (ASM) modeling archival states. Migrations are modeled as sequences of basic operations that change the archives state while respecting userdefined constraints. Among others, our target scenarios comprise legal and medical documents where considerable property changes cannot be tolerated and where constraint preservation must hold over a long period of time.

Towards constraint-based preservation in systems specification

Model transformation has applications in many areas and usually is to preserve certain properties. In model-driven software development, e.g., abstract models are transformed into more specific ones while preserving the behavior of the overall specified system. In this paper we demonstrate how constraint-based preservation, which we have initially developed in the context of digital archiving, can be applied to systems specification. We demonstrate how our approach helps to preserve communication flows inside a component-based system. In particular, formal preservation constraints allow us to prove invariance of certain significant properties of a component interaction specification if the transformation process adheres to a given set of such constraints.