András A. Benczúr

Facet of Modeling Web Information Systems from a Document-Centric View

The modeling of Information Systems in general, and Web Information Systems WIS especially, is a permanent issue so that there have been already several attempts and proposals for representing various facets of WIS. In our proposed approach, we focus on the organizational and business activity modeling and we concentrate on documents that represent the information of enterprises in the form of unstructured and semi-structured documents. The compilation of documents mirrors implicitly or explicitly the structure of enterprises, the interrelationship of business processes, and activities and tasks within processes. The documents represent, at the same time, the system roles along with tasks and activities. Our modeling approach concentrates on the co-existence and co-operation of documents and activities of business. The Story Algebra, or more generally the process algebra approach provides a formal framework that promises a formal describing method for modeling precisely the event triggered processes coupled with data in document format within an Enterprise Architecture Framework.

Temporal influence over the Last.fm social network

In a previous result, we showed that the influence of social contacts spreads information about new artists through the Last.fm social network. We successfully decomposed influence from effects of trends, global popularity, and homophily or shared environment of friends. In this paper, we present our new experiments that use a mathematically sound formula for defining and measuring the influence in the network. We provide new baseline and influence models and evaluation measures, both batch and online, for real-time recommendations with very strong temporal aspects. Our experiments are carried over the 2-year “scrobble” history of 70,000 Last.fm users. In our results, we formally define and distil the effect of social influence. In addition, we provide new models and evaluation measures for real-time recommendations with very strong temporal aspects.

Selection Process of ERP Systems

Abstract Background: The application and introduction of ERP systems have become a central issue for management and operation of enterprises. The competition on market enforces the improvement and optimization of business processes of enterprises to increase their efficiency, effectiveness, and to manage better the resources outside the company. The primary task of ERP systems is to achieve the before-mentioned objectives. Objective: The selection of a particular ERP system has a decisive effect on the future operation and profitability of the enterprise. The qualitative correlation between the size of enterprises, market position, etc. and the applied selection criteria for ERP systems should be analysed as to whether which criteria are used at multinational enterprises or at SMEs. Methods/Approach: Our research is grounded in a literature review and case studies of everyday practice related to the introduction, implementation and roll-out of ERP systems. Results: The dominant critical success factor of ERP introduction seems to be “ERP software suitability”, “Information quality”, “ERP vendor quality”. Conclusion: The set of criteria on one hand shows strong correlation with non-functional requirements codified in standards, and on the other hand with usual functional requirements for ERP systems.

Functional dependencies on extended relations defined by regular languages

In this paper, we first rephrase the notion of extended tuple as a sentence from a regular language generated by a grammar G where the nonterminal symbols of the grammar are the attribute names of the tuple. Finite sets of extended tuples play the role of extended relation instances. Then we introduce the dual language, which generates the accepted tuple-types of the extended relation. We define the syntactical form of functional dependencies for extended relation on the graph of the finite state automaton associated to the dual language. Using this model we can handle extended relations generated by recursive regular expressions too. The implication problem of our class of dependencies is decidable by a version of Chase algorithm specified on the graph of the associated FSA.

A Model for Analysis and Design of Information Systems Based on a Document Centric Approach

The recent tendency in analysis and design of Information Systems is that the emphasis is placed on the documents that are ubiquitous around information systems and organizations. The proliferation of computer literacy led to the general use of electronic documents. To understand the anticipated behaviour of Information Systems and the actual operation of a particular organization, the analysis of documents play increasingly important role. The behaviour of Information Systems can be interpreted in a framework of Enterprise Architecture and its models that are contained in it. Certain parts and entirety of various types of documents connected to business processes, tasks, roles and actors within organization. The tracking of life cycle of documents and representing the complex relationships is essential both at analysis and operation time. We propose a theoretical framework that makes use previous results of modelling and well-founded mathematical techniques.

Modeling information systems from the viewpoint of active documents

The development of document handling by organizations at the level of business processes and business information systems leads to the phenomenon that the majority of documents and their contents remain in semi-structured format and definite minorities of documents are directly mapped onto structured databases. The rapidly evolving technology on the database field provides the opportunity to manage directly the semi-structured documents in line with the requirements of business processes. A continuum of possible document formats may exist in business environments. The documents can be categorized by the organization of the underlying data collections and according to the necessity and capability of data included in documents as whether wholly or partially is to be structured. The most modern database technology yields tools for handling and retrieving data making use of semi-structured and unstructured data. Our proposed approach (1) on one hand provides a theoretical framework for modeling IS to shape into some structure, (2) on the other hand yields guidance for design method to employ it for practical application with the extension of specific elementary models. The proposed modeling method that places the emphasis onto the documents and their symbiotic life with processes helps in understanding the behavior of most modern information systems. As a result, the combination of document-centric modeling and the enterprise architecture approach gives an opportunity for a unified modeling approach that keeps an eye on Conway’s thesis that states that software architecture congruent with the structure of development team, and this statement may be paraphrased that the overall document structure may reflect the structure of the specific organization.

Static Analysis of Structural Recursion in Semistructured Databases and Its Consequences

Structural recursion is a graph traversing and restructuring operation in UnQL [7], [8], a query language for semistructured data. In this paper we consider satisfiability questions mainly in the presence of schema graphs [2], [9], which are used for describing the structure of semistructured data. We introduce a new kind of simulation between schema graphs, with which the relationships can be represented in more subtle ways. By means of operational graphs we also develop a new way for defining the semantics of structural recursions. Our results give us algorithms for checking whether a given query will satisfy the restrictions imposed by schema graphs and techniques with which these can be involved in queries. Query optimizing methods are also developed.

Application of Legal Ontologies Based Approaches for Procedural Side of Public Administration

A case study is described about a “Knowledge Warehouse” that stored originally a vast amount of texts about laws and other legal rules in spreadsheet-like structure; it permitted a full-text search to support public officers to give helping hand in various Life Events of citizens. The requirements for efficiency and effectiveness enforced a redesign and re-planning of the whole system. A preliminary conceptual design and a proof of concept prototype are developed that exploits the most recent database technologies with combination of ontologies and Description Logic.

Satisfiability and containment problem of structural recursions with conditions

Structural recursion is a general graph traversing and restructuring operation. In [9][10] we extended structural recursions with not-isempty conditions and a limited form of registers in order to simulate a large fragment of XPath 1.0 and XSLT 1.0. In this paper we address the satisfiability and containment problem of structural recursions with not-isempty conditions. We examine two cases, when else-branches are allowed in the conditions and when they are not. In the second case it turns out that the satisfiability problem can be solved in quadratic time, while the question of containment is coNP-complete in general. In the first case both problems are PSPACE-complete in general. Our results have their theoretical importance of their own, however, we hope that they can also be used to fill in some of the gaps in the research of XPath and XSLT.

Classical and weighted knowledgebase transformations

Abstract In this paper, there is a review of some knowledgebase change operators, namely the revision, update, (symmetrical) model-fitting well known in the propositional case and some new problems concerning them. There is an extended set of axioms to avoid a certain problem in connection with revision. Based on the propositional case, we give some generalization of revision for first-order case. Furthermore we define an extension of the propositional knowledgebase to weighted knowledgebase. Finally we deal with the weighted knowledgebase transformations.