Soundness in verification of algebraic specifications with OBJ

The algebraic specification tools of the OBJ family have no notion of open terms or quantifiers. Nonetheless there are methods of proving universally quantified statements about specifications. These methods are examined and found to be unsound.     

Many-valued equalities, singletons and fuzzy partitions

 This paper deals with interrelations between many-valued equalities, singletons and many-valued partitions. Applications to the principle of sliding transition and to fuzzy control theory are given.     

Consistency,redundancy, and implied equalities in linear systems

Systems of linear inequalities have been studied for more than a century, but many of the results were developed during the early years of linear programming (1950s). New developments in linear programming plus interests in artificial intelligence have recently produced new results. One question is that of consistency: Does there exist a solution to satisfy all linear relations simultaneously? If so, are some of the relations redundant — that is, implied by the others? Are there implied equalities — that is, does some (weak) inequality have to hold with equality in every feasible solution? This paper brings together the main theorems that address these questions, unifies the framework, and presents some new results.     

Fast OBJ file importing and parsing in CUDA

Computational Visual Media - Alias-Wavefront OBJ meshes are a common text file type for transferring 3D mesh data between applications made by different vendors. However, as the mesh complexity...     

Featherweight Java with dynamic and static overloading

We propose FMJ (Featherweight Multi Java), an extension of Featherweight Java with encapsulated multi-methods thus providing dynamic overloading. Multi-methods (collections of overloaded methods associated to the same message, whose selection takes place dynamically instead of statically as in standard overloading) are a useful and flexible mechanism which enhances re-usability and separation of responsibilities. However, many mainstream languages, such as, e.g., Java, do not provide it, resorting to only static overloading.The proposed extension is conservative and type safe: both “message-not-understood” and “message-ambiguous” are statically ruled out. Possible ambiguities are checked during type checking only on method invocation expressions, without requiring to inspect all the classes of a program. A static annotation with type information guarantees that in a well-typed program no ambiguity can arise at run-time. This annotation mechanism also permits modeling static overloading in a smooth way.Our core language can be used as the formal basis for an actual implementation of dynamic (and static) overloading in Java-like languages.     

Generalizing DPLL and satisfiability for equalities

We present GDPLL, a generalization of the DPLL procedure. It solves the satisfiability problem for decidable fragments of quantifier-free first-order logic. Sufficient conditions are identified for proving soundness, termination and completeness of GDPLL. We show how the original DPLL procedure is an instance. Subsequently the GDPLL instances for equality logic, and the logic of equality over infinite ground term algebras are presented. Based on this, we implemented a decision procedure for inductive datatypes. We provide some new benchmarks, in order to compare variants.     

New techniques for linear arithmetic: cubes and equalities

We present several new techniques for linear arithmetic constraint solving. They are all based on the linear cube transformation, a method presented here, which allows us to efficiently determine whether a system of linear arithmetic constraints contains a hypercube of a given edge length. Our first findings based on this transformation are two sound tests that find integer solutions for linear arithmetic constraints. While many complete methods search along the problem surface for a solution, these tests use cubes to explore the interior of the problems. The tests are especially efficient for constraints with a large number of integer solutions, e.g., those with infinite lattice width. Inside the SMT-LIB benchmarks, we have found almost one thousand problem instances with infinite lattice width. Experimental results confirm that our tests are superior on these instances compared to several state-of-the-art SMT solvers. We also discovered that the linear cube transformation can be used to investigate the equalities implied by a system of linear arithmetic constraints. For this purpose, we developed a method that computes a basis for all implied equalities, i.e., a finite representation of all equalities implied by the linear arithmetic constraints. The equality basis has several applications. For instance, it allows us to verify whether a system of linear arithmetic constraints implies a given equality. This is valuable in the context of Nelson–Oppen style combinations of theories.     

Gordon's computer: A hardware verification case study in OBJ3

The use of the algebraic specification language OBJ3 [26] in hardware verification has been demonstrated on a number of small examples [62, 20, 63] and some large but regular structures [12, 11]. In this paper, we show that the approach can also be used for specifying and verifying large, irregular structures. We specify and partially verify Gordon's computer, a simple microprocessor. We believe that this is the largest hardware verification case study undertaken with OBJ3 so far.     

面向过程、面向对象与泛型程序设计的对比分析

编程语言在软件设计领域经历过三次重大的变革,它们分别是面向过程的编程,面向对象的编程和泛型编程.其中的每一次变革不仅影响到编程语言本身,更影响到软件工程中的各个领域.文章介绍了这三种程序的设计方法,并且对其进行了比较和分析.     

Programming with logical queries, bulk updates, and hypotheticalreasoning

The paper presents a language of update programs that integrates logical queries, bulk updates and hypothetical reasoning in a seamless manner. There is no syntactic or semantic distinction between queries and updates. Update programs extend logic programs with negation in both syntax and semantics. They allow bulk updates in which an arbitrary update is applied simultaneously for all answers of an arbitrary query. Hypothetical reasoning is naturally supported by testing the success or failure of an update. We describe an alternating fixpoint semantics of update programs and show that it can express all nondeterministic database transformations     

Structure and parametrization of periodic linear systems

In this paper, the beginnings of a structure theory for discrete-time periodic linear systems are developed. Canonical forms for state space realizations are described, structural invariants and their combinatorics are studied and geometric aspects of the parametrization of periodic systems are treated.     

Genetic Programming and Autoconstructive Evolution with the Push Programming Language

Push is a programming language designed for the expression of evolving programs within an evolutionary computation system. This article describes Push and illustrates some of the opportunities that it presents for evolutionary computation. Two evolutionary computation systems, PushGP and Pushpop, are described in detail. PushGP is a genetic programming system that evolves Push programs to solve computational problems. Pushpop, an autoconstructive evolution system, also evolves Push programs but does so while simultaneously evolving its own evolutionary mechanisms.     

Prototyping and Programming with Relations

We give a survey on the use of relational algebra for problem specification and program development over relation-based discrete structures and show how the relation-algebraic prototyping and visualization tool Rel View can support this approach.     

Programming with generators

Tagging of objects produced by generators is a simple mechanism for the synchronization of generators. Such tagging is proposed as a reliable software design technique for problems based on data streams. It is used to develop programs for two-way merge and file update.     

Programming with Invariants

The use of a restricted class of invariants as part of a language supports both the accurate synthesis of high-level programs and their translation into efficient implementations.     

Programming with Python

Python is a powerful, easy-to-learn programming language based on traditional languages but better suited to current operating systems, networks, and hardware.     

The impact of parametrization in memetic evolutionary algorithms

Memetic (evolutionary) algorithms integrate local search into the search process of evolutionary algorithms. As computational resources have to be spread adequately among local and evolutionary search, one has to care about when to apply local search and how much computational effort to devote to local search. Often local search is called with a fixed frequency and run for a fixed number of iterations, the local search depth. There is empirical evidence that these parameters have a significant impact on performance, but a theoretical understanding as well as concrete design guidelines are missing.     

Localization and parametrization of linear multidimensional control systems

We study the link existing between the parametrization of differential operators by potential-like arbitrary functions and the localization of differential modules, while applying these results to the parametrization of linear multidimensional control systems. We show that the localization of differential modules is a natural way to generalize some well-known results on transfer matrix, classically obtained by using Laplace transform, to time-varying ordinary differential control systems and to partial differential control systems with variable coefficients. In particular, we show that the parametrizations obtained by localization are simpler than those obtained by formal duality but are worse in the sense of Palamodov–Kashiwara's classification of differential modules.