Data checkpointing is an important problem of distributed database systems. Actually, transactions establish dependence relations on data checkpoints taken by data object managers. So, given an arbitrary set of data checkpoints (including at least a single data checkpoint from a data manager, and at most a data checkpoint from each data manager), an important question is the following one: \Can...

In this work we will study the problem of the design of the "Integration Model for Distributed Database System". We particularly design the canonical model through the ontological handling of the information. The ontology is designed in a way that allows the description of a database like a set of representative terms of its different components. In this ontology, the definitions use classes, r...

Distributed systems are vital for the efficient processing required in military and commercial applications. For many of these applications, it is especially important that the distributed data base management systems (DDBMS) operate in a secure manner. For example, the DDBMS should allow users, who are cleared at different security levels access to the data base at different levels of data sen...

We consider the problem of searching a set of data repositories, each managed by an independent agent which is able to handle queries from users, as well as queries from peer agents. Given a query, an agent’s task is to find a closest match to the query over all the distributed databases. The agents search the distributed databases cooperatively by routing queries with each other. However, it i...

We analyze the inference problem for distributed databases.

Most distributed knowledge discovery approaches view data distribution as a technical issue and combine local models aiming at a single global model. This however, is unsuitable for inherently distributed databases, which often produce models that differ semantically. In this paper we present an approach for distributed classification that uses the pairwise similarity of local models in order t...

Distributed database systems require a commit process to preserve the ACID property of transactions executed on a number of system sites. With the appearance of main memory database system, the database processing time has been reduced in the order of magnitude, since the database access does not incur any disk access at all. However, when it comes to distributed main memory database systems, t...

Distributed relational databases beneet greatly from fragmentation and allocation and these beneets should be realized in a distributed object environment. Fragmentation enhances application performance by reducing the amount of irrelevant data accessed and the amount of data transferred unnecessarily between distributed sites. This paper presents a review of early work on distributed database ...

The implicit yes{vote commit protocol (IYV), proposed for future gigabit{networked distributed databases, reduces the time required to commit a distributed transaction at the expense of independent recovery of failed participant sites. In this paper, we propose a novel coordination scheme for IYV that reduces the window of vulnerability to blocking and minimizes the time required for the sites ...

As computerization in healthcare services increase, the amount of available digital data is growing at an unprecedented rate and as a result healthcare organizations are much more able to store data than to extract knowledge from it. Today the major challenge is to transform these data into useful information and knowledge. It is important for healthcare organizations to use stored data to impr...