The OASIS Platform
Within the OASIS Project the technological aspects of the OASIS Platform play a central role. It is comprised of the Middleware, the Archive Adapters and the OASIS Front-end and regulates the inteaction of the different components.
The theoretical base of a mutual metadata model, including translation rules, has been elaborated upon in the chapter on metadata. This chapter concentrates on the technical concept and the system architecture of the OASIS Platform
As a newly created configuration the Platform directs users' queries and relays them to the respective data systems. The search results are presented in a central research interface.
Three technical core elements of the Platform are
Three core Elements
- Database Adapter
- Middleware Software
Technologically, the translation module between the partner institutions databases and the Platform is manifested in a Database Adapter. It is a software module, which translates the existing tables, lists and metadata categories of the partner’s databases on a common scheme. The software package was comment out by the AGH. As a freely available software (Freeware) package it will be available to institutions who might want to join the Platform after the funding phase expires. Thus the participation in the instigated communication and distribution infrastructure is enabled.
The Middleware is connected to the partner databases via the database adapters. Their basic role is to combine and to channel search requests. In addition it prepares the search results and relays them to the front-end.
The Front-end finally is where the results are presented. It is possible to develop other front ends. This is why an Search Interface has been developed, which may be integrated into the partners websites. This search mask facilitates a query from the local page to the middleware, and thus to research the connected archives.
Every partner database appears to the platform on the database adapters’ side in the communication model as a self-contained (database-) entity.
To be able to abstract from the different entities, the partners installed so-called Daily Caches within the database adapters. They temporarily mirror the database content (see dayli cash descriptions ff.) and are re-filled daily with data from the archives.
The existing metadata structures are only adjusted to the metadata standard via the mapping-mechanism when transferred to the Daily Cache tables.
The communication between server and client is asynchronous. The queries are saved in form of clear-text queries in a queue and processed one after the other. For every query an asynchronous search process is initiated. The number of entities (databases) which can communicate via the Database Adapter with the middleware at the same time is limited. In addition a special database structure was developed for the middleware, which displays the communication paths.
In addition to specially developed technical documentations and installation guides, the experience reports of the partners are helpful for installation of the database adapters.
The Platform adheres to the guidelines of the OAI | Open Archives Initiative. OAI provides interoperability standards and aims to facilitate the efficient dissemination of content.
As a distributed electronic art platform for the Project the stress on unique identifiers was necessary. In an art context the same artwork may appear with an identical title, without it being a redundant record. This is because of editions. Therefore it was important to connect the sources clearly with the partner institution (data provider). These unique identifiers are therefore better compared to the DNS-entry of a web server than a identification tag.
The main feature of OASIS is the lack of a central cash infrastructure. Only the partners may cash locally, on the Platform itself the metadata and data are only presented, not cashed.
The → Database Adapter is implemented on the partners' databases as a software package and translates their scheme on the shared Metadata Model.
The → Middleware enables technically the networked search through locally distributed databases of the partners.
This link leads directly to the interface of the networked → Search here.
Find more information about → Frontend.
OAI | Open Archives Initiative
Get to know the → Partners.
Find more information about the internal
→ communication of the Platform.
Digital rendering → formats usually condense the image information. You can find general information → here.
The internal algorithms involved in the process of digitisation and condensation can lead to image modifications. We tested a series of → Codecs and condensation methods.