12169882
Capturing more world knowledge in the requirements specification
The view is adopted that software requirements involve the representation (modeling) of considerable real-world knowledge, not just functional specifications. A framework (RMF) for requirements models is presented and its main features are illustrated. RMF allows information about three types of conceptual entities (objects, activities, and assertions) to be recorded uniformly using the notion of properties. By grouping all entities into classes or metaclasses, and by organizing classes into generalization (specialization) hierarchies, RMF supports three abstraction principles (classification, aggregation, and generalization) which appear to be of universal importance in the development and organization of complex descriptions. Finally, by providing a mathematical model underlying our terminology, we achieve both unambiguity and the potential to verify consistency of the model.
35597586
On the Frame Problem in Procedure Specifications
The paper provides examples of situations where formal specifications of procedures in the standard pre/postcondition style become lengthy, cumbersome and difficult to change, a problem which is particularly acute in the case of object oriented specifications with inheritance. We identify the problem as the inability to express that a procedure changes only those things it has to, leaving everything else unmodified, and review some attempts at dealing with this "frame problem" in the software specification community. The second part of the paper adapts a recent proposal for a solution to the frame problem in artificial intelligence-the notion of explanation closure axioms-to provide an approach whereby one can state such conditions succinctly and modularly, with the added advantage of having the specifier be reminded of things that she may have omitted saying in procedure specifications. Since this approach is based on standard predicate logic, its semantics are relatively straightforward. The paper also suggests an algorithm which generates syntactically the explanation closure axioms from the pre/postcondition specifications, provided they are written in a restricted language; it also suggests a model theory supporting it. >
5771700
Information services for the Web: building and maintaining domain models
The World Wide Web is serving as a leading vehicle for information dissemination by offering information services, such as product information, group interactions, or sales transactions. Three major factors affect the performance and reliability of information services for the Web: the distribution of information which has resulted from the globalization of information systems, the heterogeneity of information sources, and the sources' instability caused by their autonomous evolution. This paper focuses on integrating existing information sources, available via the Web, in the delivery of information services. The primary objective of the paper is to provide mechanisms for structuring and maintaining a domain model for Web applications. These mechanisms are based on conceptual modeling techniques, where concepts are being defined and refined within a meta-data repository through the use of instantiation, generalization and attribution. Also, active databases techniques are exploited to provide robust mechanisms for maintaining a consistent domain model in a rapidly evolving environment, such as the Web.
596050
Building knowledge base management systems

Abstract.Advanced applications in fields such as CAD, software engineering, real-time process control, corporate repositories and digital libraries require the construction, efficient access and management of large, shared knowledge bases. Such knowledge bases cannot be built using existing tools such as expert system shells, because these do not scale up, nor can they be built in terms of existing database technology, because such technology does not support the rich representational structure and inference mechanisms required for knowledge-based systems. This paper proposes a generic architecture for a knowledge base management system intended for such applications. The architecture assumes an object-oriented knowledge representation language with an assertional sublanguage used to express constraints and rules. It also provides for general-purpose deductive inference and special-purpose temporal reasoning. Results reported in the paper address several knowledge base management issues. For storage management, a new method is proposed for generating a logical schema for a given knowledge base. Query processing algorithms are offered for semantic and physical query optimization, along with an enhanced cost model for query cost estimation. On concurrency control, the paper describes a novel concurrency control policy which takes advantage of knowledge base structure and is shown to outperform two-phase locking for highly structured knowledge bases and update-intensive transactions. Finally, algorithms for compilation and efficient processing of constraints and rules during knowledge base operations are described. The paper describes original results, including novel data structures and algorithms, as well as preliminary performance evaluation data. Based on these results, we conclude that knowledge base management systems which can accommodate large knowledge bases are feasible.

8955752
Modeling Social and Individual Trust in Requirements Engineering Methodologies
When we model and analyze trust in organizations or information systems we have to take into account two different levels of analysis: social and individual. Social levels define the structure of organizations, whereas individual levels focus on individual agents. This is particularly important when capturing security requirements where a “normally” trusted organizational role can be played by an untrusted individual. 
 
Our goal is to model and analyze the two levels finding the link between them and supporting the automatic detection of conflicts that can come up when agents play roles in the organization. We also propose a formal framework that allows for the automatic verification of security requirements between the two levels by using Datalog and has been implemented in CASE tool.
5979580
ST-Tool: A CASE Tool for Modeling and Analyzing Trust Requirements
ST-Tool is a graphical tool integrating an agent-oriented requirements engineering methodology with tools for the formal analysis of models. Essentially, the tool allows designers to draw visual models representing functional, security and trust requirements of systems and, then, to verify formally and automatically their correctness and consistency through different model-checkers.
2515059
Modeling security requirements through ownership, permission and delegation
Security requirements engineering is emerging as a branch of software engineering, spurred by the realization that security must be dealt with early on during the requirements phase. Methodologies in this field are challenging, as they must take into account subtle notions such as trust (or lack thereof), delegation, and permission; they must also model entire organizations and not only systems-to-be. In our previous work we introduced Secure Tropos, a formal framework for modeling and analyzing security requirements. Secure Tropos is founded on three main notions: ownership, trust, and delegation. In this paper, we refine Secure Tropos introducing the notions of at-least delegation and trust of execution; also, at-most delegation and trust of permission. We also propose monitoring as a security design pattern intended to overcome the problem of lack of trust between actors. The paper presents a semantic for these notions, and describes an implemented formal reasoning tool based on Datalog.
661878
Text Mining Through Semi Automatic Semantic Annotation
The Web is the greatest information source in human history. Unfortunately, mining knowledge out of this source is a laborious and error-prone task. Many researchers believe that a solution to the problem can be founded on semantic annotations that need to be inserted in web-based documents and guide information extraction and knowledge mining. In this paper, we further elaborate a tool-supported process for semantic annotation of documents based on techniques and technologies traditionally used in software analysis and reverse engineering for large-scale legacy code bases. The outcomes of the paper include an experimental evaluation framework and empirical results based on two case studies adopted from the Tourism sector. The conclusions suggest that our approach can facilitate the semi-automatic annotation of large document bases.
2612575
A Distributed Rule Mechanism for Multidatabase Systems
We describe a mechanism based on distributed Event-Condition-Action (ECA) rules that supports data coordination in a multidatabase setting. The proposed mechanism includes an ECA rule language and a rule execution engine that transforms and partitions rules when they are first posted, and then coordinates their execution. The paper also presents a prototype implementation in a simulated environment as well as preliminary experimental results on its performance. This work is part of an on-going project intended to develop data coordination techniques for peer-to-peer databases.