An Introduction

Computing devices are permanent attendants in our live, for private and professional activities. Communication has largely shifted to digital environment, e-mail or instant messaging, and we record and store videos, audio, and pictures. Our daily activities are digital expressions, from calendar postings to financial transactions nearly every business activity results in a digital footprint. We are using all kinds of equipment to interact and our information is wide spread from mobile devices to personal computers, company servers, notebooks, the World Wide Web, and cloud applications.

In addition to their original purpose of computing, data storage has become an important service. The increasing availability and decreasing cost of digital memory capacity resulted in a trend to store and keep every bit of private and company data for further usage.

Facing this trend, the need for management mechanisms emerged that allow humans to cope with such amounts of data, and to search and retrieve information if demanded. Metadata, which means descriptive information about data, can be used to organize personal or company information space. However, efficient metadata management requires infrastructures in terms of data models, meta data models, and corresponding access algorithms.

Hierarchical file systems have been the de-facto standard for personal data management since the invention of the first personal computers in the late 1970s. Since that time, hierarchical directory structures have been used to organize, describe, and retrieve files. The main reason for this spreading lies in the fact that files are highly generic storage containers: they are capable of storing basically any kind of data in any kind of format. On the other side, file systems do not provide means for representing the semantics of files.

Current systems provide possibilities to annotate files, but they lack of unified understanding of syntax and semantics. Exchanging annotations between systems, and to implement applications that utilize these features in a way that is helpful to end users would ease work.

Semantic technologies are the approach towards such information exchange, and the main building block of the Semantic Web is the Resource Description Framework (RDF). This graph-based meta model is used to represent any kind of information.

Similar to the semantic evolution of the World Wide Web from a web of documents to a web of data and things, information technology starts shifting from heaps of unrelated binary objects to small but enriched semantic webs. They become structurally rich information meshes that are present on every computing device.

To accommodate this AL!SE integrates elements from semantic web technology and elements from file systems into a single information representation model. AL!SE provides an expressive data model that serves as a common basis for applications to store and manage data.