Effect preservation in transaction processing in rule triggering systems

Rules provide an expressive means for implementing database behavior: They cope with changes and their ramifications. Rules are commonly used for integrity enforcement, i.e., for repairing database actions in a way that integrity constraints are kept. Yet, Rule Triggering Systems fall short in enforcing effect preservation, i.e., guaranteeing that repairing events do not undo each other, and in particular, do not undo the original triggering event. A method for enforcement of effect preservation on updates in general rule triggering systems is suggested. The method derives transactions from rules, and then splits the work between compile time and run time. At compile time, a data structure is constructed, that analyzes the execution sequences of a transaction and computes minimal conditions for effect preservation. The transaction code is augmented with instructions that navigate along the data structure and test the computed minimal conditions. This method produces minimal effect preserving transactions, and under certain conditions, provides meaningful improvement over the quadratic overhead of pure run time procedures. For transactions without loops, the run time overhead is linear in the size of the transaction, and for general transactions, the run time overhead depends linearly on the length of the execution sequence and the number of loop repetitions. The method is currently being implemented within a traditional database system

An Overview of F-OML: An F-Logic Based Object Modeling Language

F-OML is an F-Logic based Object Modeling Language. It can be used for extending UML diagrams, reasoning about them, testing UML models, and defining their syntax (meta-modeling) and semantics. This wide range of applications of F-OML stems from several language features, including polymorphism, multi-level object modeling, and model instantiation. F-OML supports modeling of classes and properties. F-OML is layered on top of an elegant formal language of guarded path expressions, called PathLP, which is used to define objects and their types. PathLP is a logic programming language, inspired by F-logic. It supports path expressions, rules, constraints, and queries, and it is easy to implement by translation into a tabling Prolog engine, such as XSB. In this short overview we informally describe the main constructs of PathLP and F-OML, and provide examples that demonstrate the four modes of F-OML usage. Formal definitions and additional details are found in the full paper. Finally, we analyze how language features contribute to its expressiveness, and provide a brief comparison with OCL

Model Correctness Patterns as an Educational Instrument

UML class diagrams play a central role in modeling activities. Given the difficulty in producing high quality models, modelers must be equipped with an awareness of model design problems and the ability to identify and correct such models. In this paper we observe the role of class diagram correctness patterns as an educational instrument for improving class diagram modeling. We describe a catalog of correctness and quality design (anti)-patterns for class diagrams. The patterns characterize problems, analyze their causes and provide repairing advice. Pattern specification requires an enhancement of the class diagram meta-model. The pattern classification has a major role in clarifying design problems. Finally, we describe an actual experiment of using the catalog for teaching modeling

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

The F-Logic Approach for Description Languages

The Frame-logic (F-logic) approach of [20] is suggested as an underlying framework for description languages. F-logic is shown to provide a full account for description languages, without losing the direct semantics and the descriptive nature. It can support such desirable features as high order role fillers, collective entities, intensions, roles as first class objects and n-ary relationships. Yet, its semantics is first order. In an F-logic based description language, few description constructs are built in, and concepts, roles, and terminological operators are definable. Discussion of desirable features in descriptions is made possible within a single, uniform framework, that also coherently integrates with logic programming and deductive, object-oriented database technology. Typical descriptive operators can be defined in the language, thereby yielding a flexible description language, in which not all operators must be built in. keywords: object-oriented representation, F-logic, de..

Compositional Semantics for Description Knowledge Bases with Rules

Descriptions and Rules are different, complementary, essential forms of knowledge. Descriptions are analytic and closed; rules are contingent and open. The two forms can be integrated either by compiling one form within the other, or by constructing a hybrid framework. The hybrid solution keeps the modular independent status of each approach, but needs an underlying integration framework, in which a coherent compositional semantics can be defined. In this paper we introduce an architecture for a hybrid knowledge base that integrates descriptions with expressive object-oriented rules. The knowledge base manages a database of explicit descriptions and facts, by consulting two separate reasoners: DL -- The Description Languages reasoner, and R -- The Rules reasoner. The architecture generalizes all existing hybrids of descriptions and rules. Its declarative semantics relies on F-Logic as an underlying semantics, and is consistent with the (sometimes only operational) semantics of existi..

Temporal Reasoning in Process Planning

Computer-aided process planning has been recognized as an important tool for coordinating the different operations involved in making the product. While temporal knowledge is central to the design of efficient and reliable process plans, little attention is given to the integration of process planning and temporal processing and reasoning. To fill the void, we propose in this paper a practical approach, which is inspired by the framework of Temporal Constraint Satisfaction Problem ~TCSP!, to integrate process planning and temporal reasoning. We show that a TCSP formulation is a subset of a formulation using a reified temporal logic, and discuss the advantages of using such a restricted model. To reflect more realistic process planning encountered in real manufacturing environments, we present a model, called n-TCSP, which is a generalization of the TCSP framework. We envision the proposed temporal reasoning framework as one of the modules in the evolving new intelligent computer-aided process planning