J. Santiago Jorge

Certifying properties of an efficient functional program for computing Gröbner bases

This paper explores the certification of properties of an efficient functional program in the area of symbolic computation: the calculation of Grobner basis of a set of multivariate polynomials. Our experience in the development of industrial systems and the certification of some of its relevant properties has led us to use a methodology consisting of functional programs to write the code and the formal verification of fundamental properties. The functional language OBJECTIVE CAML has been chosen to implement the program. To verify the properties two approaches are explored: manual proofs that reason directly over the source code of the algorithms, applying techniques like equational reasoning, and theorem provers that are used as a tool to help us certify a model of the real system. The chosen proof assistant is COQ. Not only will the certification of the software be taken into consideration but also its efficiency. In addition, we present a graphical interface which eases the use of the program.

Managing the Risks of Risk Management

Enterprise Risk Management (ERM) is a field of enormous importance due to its economic repercussion. More and more companies are paying attention to it, given there is significant economic savings for attending to the various aspects of risk. At the same time, ERM has witnessed a shift in the way firms manage the many uncertainties that stand in the way of achieving their strategic, operational and financial objectives. Nevertheless, existing Risk Management Systems (RMIS) are neither powerful, nor flexible enough to model the complexity of the risk management process. In this paper we will examine these issues in greater detail, explaining the existing problem and proposing a software system that addresses them. We will also show the actual design and operation of ARMISTICE (Advanced Risk Management Information System: Tracking Insurances, Claims and Exposures), a successful RMIS case study.

A distributed filesystem for spare storage

Having access to large quantities of storage space has always been a problem. Traditionally, large storage capacity has been expensive, using dedicated storage systems (NAS), or more complex networked storage (SAN). In many cases these solutions are overkill both in price and in features. Many small offices and research labs with limited budget have computers with unused disk space that could be used as shared storage. A distributed filesystem can take advantage of the storage space of several computers to provide a larger storage. For a small office or lab this filesystem would have to provide easy integration into the infrastructure and reasonable scalability. In this work we propose a filesystem that provides access to a large storage using the unused space in a network of workstations.

The Tertiary Level in a Functional Cluster-Based Hierarchical VoD Server

A Video-On-Demand (VoD) server provides video services to the end user, that can request a piece of video at any time, without any previously established timetable. The growing demand of such services suggests the design of flexible and scalable VoD servers, both in storage capacity and bandwidth. The tertiary level of a VoD server that is being implemented in top of a cheap Linux cluster, based on a hierarchical distributed architecture, using the functional programming language Erlang, is proposed in this paper.

Using Coq to Prove Properties of the Cache Level of a Functional Video-on-Demand Server

In this paper we describe our experiences applying formal software verification in a real-world distributed Video-on-Demandserver. As the application of formal methods to large systems is extremely difficult, relevant properties of a particular subsystem have been identified and then verified separately. Conclusions on the whole system can be drawn later. The development consists of two parts: first, the definition of the algorithm in the coq proof assistant; second, codification of the theorems with the help of some new tactics derived from the abstraction of verification patterns common to different proofs.

Verification of program properties using different theorem provers: a case study

This paper explores the use of theorem provers to certify particular properties of software. Two different proof assistants are used to illustrate the method: Coq and Pvs. By comparing two theorem provers, conclusions about their suitability can be stated. The selected scenario is part of a real-world application: a distributed Video-on-Demand server. The development consists on two steps: first, the definition of a model of the algorithm to be studied in the proof assistants; second, the development and proving of the theorems.

Towards a certified and efficient computing of gröbner bases

In this paper, we present an example of the implementation and verification of a functional program. We expose an experience in developing an application in the area of symbolic computation: the computing of Grobner basis of a set of multivariate polynomials. Our aim is the formal certification of several aspects of the program written in the functional language Caml. In addition, efficient computing of the algorithm is another issue to take into account.