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

Logical Foundations of Object-Oriented and Frame-Based Languages

We propose a novel logic, called Frame Logic (abbr., F-logic), that accounts in a clean, declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, methods, encapsulation, and others. In a sense, F-logic stands in the same relationship to the object-oriented paradigm as classical predicate calculus stands to relational programming. The syntax of F-logic is higher-order, which, among other things, allows the user to explore data and schema using the same declarative language. F-logic has a model-theoretic semantics and a sound and complete resolution-based proof procedure. This paper also discusses various aspects of programming in declarative object-oriented languages based on F-logic

Timeless Strategy Meets New Medium: Going Negative on Congressional Campaign Websites, 2002-2006

Abstract: In a few short years, the World Wide Web has become a standard part of candidates’ campaign tool kits. Virtually all candidates have their own sites; and voters, journalists, and activists visit the sites with increasing frequency. In this paper, we study what candidates do on these sites—in terms of the information they present—by exploring one of the most enduring and widely debated campaign strategies: “going negative. ” Comparing data from over 700 congressional candidate websites, over three election cycles (2002, 2004, and 2006), with television advertising data, we show that candidates go negative with similar likelihoods across these media. We also find that while similar dynamics drive negativity on the Web and in television advertising, there are some notable differences. These differences likely stem, in part, from the truncated sample available with television data (i.e., many candidates do not produce ads). Our results have implications for understanding negative campaigning, and for the ways in which scholars can study campaign dynamics

Semantic web service choreography: contracting and enactment

Abstract. The emerging paradigm of service-oriented computing requires novel techniques for various service-related tasks. Along with automated support for service discovery, selection, negotiation, and composition, support for automated service contracting and enactment is crucial for any large scale service environment, where large numbers of clients and service providers interact. Many problems in this area involve reasoning, and a number of logic-based methods to handle these problems have emerged in the field of Semantic Web Services. In this paper, we build upon our previous work where we used Concurrent Transaction Logic (CTR) to model and reason about service contracts. We significantly extend the modeling power of the previous work by allowing iterative processes in the specification of service contracts, and we extend the proof theory of CTR to enable reasoning about such contracts. With this extension, our logic-based approach is capable of modeling general services represented using languages such as WS-BPEL

Modeling and Analysis of Interactions in Virtual Enterprises

Advances in computer networking technology and open system standards are making the creation and management of virtual enterprises feasible. A virtual enterprise is a temporary consortium of autonomous, diverse, and possibly geographically dispersed organizations that pool their resources to meet short-term objectives and exploit fastchanging market trends. For a virtual enterprise to succeed, its business processes must be automated, and its startup costs must be minimized. In this paper we describe a formal framework for modeling and reasoning about interactions in a virtual enterprise. Such a framework will form the basis for tools that provide automated support for creation and operation of virtual enterprises. 1