A Refinement Calculus for Logic Programs

Existing refinement calculi provide frameworks for the stepwise development of imperative programs from specifications. This paper presents a refinement calculus for deriving logic programs. The calculus contains a wide-spectrum logic programming language, including executable constructs such as sequential conjunction, disjunction, and existential quantification, as well as specification constructs such as general predicates, assumptions and universal quantification. A declarative semantics is defined for this wide-spectrum language based on executions. Executions are partial functions from states to states, where a state is represented as a set of bindings. The semantics is used to define the meaning of programs and specifications, including parameters and recursion. To complete the calculus, a notion of correctness-preserving refinement over programs in the wide-spectrum language is defined and refinement laws for developing programs are introduced. The refinement calculus is illustrated using example derivations and prototype tool support is discussed.Comment: 36 pages, 3 figures. To be published in Theory and Practice of Logic Programming (TPLP

Loan Data Governance

The purpose of this project was to build a quick, intuitive, customizable reconciliation tool for Angelo, Gordon & Co. The current tool was strong in functionality but weak in user interface. New reconciliations took weeks of setup and generated hard-to-read reports. Further, every report cost money. We worked closely with the sponsor to develop an extremely intuitive and user-friendly tool that is free to use, and only take minutes to create new, large reconciliations

Angelo Gordon: Loan Data Governance

The purpose of this project was to build a quick, intuitive, customizable reconciliation tool for Angelo, Gordon & Co. The current tool was strong in functionality but weak in user interface. New reconciliations took weeks of setup and generated hard-to-read reports. Further, every report cost money. We worked closely with the sponsor to develop an extremely intuitive and user-friendly tool that is free to use, and only take minutes to create new, large reconciliations

Is Classical Christian Education Compatible with a Reformed Christian Perspective on Education?

Is the growing classical Christian education movement, based on Dorothy Sayers’ trivium methodology, compatible to a Reformed Christian perspective on education? The classical Christian position claims that children progress through three stages of development and that the three components of the trivium complement these natural learning stages. The first stage involves memorizing facts through chants, stories and songs. In the second stage students learn how to argue and analyze by means of formal training in logic. The third stage focuses on learning to express knowledge persuasively and elegantly. When compared to the Reformed understanding of covenant children as well as Reformed purposes and methods of education, classical Christian education is found to be too intellectualistic and elitist to be compatible with a Reformed Christian perspective on education

Three computer programs for n-body trajector- ies and interplanetary trajectories

Input and operating instructions, and sample problems for IBM 7094 computer programs - interplanetary trajectory program, n-body trajectory program, and sensitivity coefficient