45,159 research outputs found

    DIRECT DIGITAL CONTROL IN A COMPLEX OF SOFTWARE DESIGN OF DIGITAL CONTROL SYSTEMS

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    This article provides the functionality of creating direct digital control devices in the computer-aided design of digital automatic control systems (CAD of digital ACS), in a complex of software design of digital control systems (SDSDC complex) for automated process control systems. Technical tools are defined by the international standard IEC 61131-1: 2003 (Part 1: General data). The possibility of implementing SDSDC complex in direct digital control, single-cycle and multi-cycle ladder diagrams, identification of objects of management and synthesis of digital controllers in comparison with the international standard IEC 61131-3: 2003 (Part 3: Programming Languages) are evaluated. Users’ productivity is estimated as well as the possibility of its separation between the users at different stages of the design of digital systems of automatic control is assessed

    What Does Aspect-Oriented Programming Mean for Functional Programmers?

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    Aspect-Oriented Programming (AOP) aims at modularising crosscutting concerns that show up in software. The success of AOP has been almost viral and nearly all areas in Software Engineering and Programming Languages have become "infected" by the AOP bug in one way or another. Interestingly the functional programming community (and, in particular, the pure functional programming community) seems to be resistant to the pandemic. The goal of this paper is to debate the possible causes of the functional programming community's resistance and to raise awareness and interest by showcasing the benefits that could be gained from having a functional AOP language. At the same time, we identify the main challenges and explore the possible design-space

    Aspect-Oriented Programming

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    Aspect-oriented programming is a promising idea that can improve the quality of software by reduce the problem of code tangling and improving the separation of concerns. At ECOOP'97, the first AOP workshop brought together a number of researchers interested in aspect-orientation. At ECOOP'98, during the second AOP workshop the participants reported on progress in some research topics and raised more issues that were further discussed. \ud \ud This year, the ideas and concepts of AOP have been spread and adopted more widely, and, accordingly, the workshop received many submissions covering areas from design and application of aspects to design and implementation of aspect languages

    Fifty years of Hoare's Logic

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    We present a history of Hoare's logic.Comment: 79 pages. To appear in Formal Aspects of Computin

    Permission-Based Separation Logic for Multithreaded Java Programs

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    This paper presents a program logic for reasoning about multithreaded Java-like programs with dynamic thread creation, thread joining and reentrant object monitors. The logic is based on concurrent separation logic. It is the first detailed adaptation of concurrent separation logic to a multithreaded Java-like language. The program logic associates a unique static access permission with each heap location, ensuring exclusive write accesses and ruling out data races. Concurrent reads are supported through fractional permissions. Permissions can be transferred between threads upon thread starting, thread joining, initial monitor entrancies and final monitor exits. In order to distinguish between initial monitor entrancies and monitor reentrancies, auxiliary variables keep track of multisets of currently held monitors. Data abstraction and behavioral subtyping are facilitated through abstract predicates, which are also used to represent monitor invariants, preconditions for thread starting and postconditions for thread joining. Value-parametrized types allow to conveniently capture common strong global invariants, like static object ownership relations. The program logic is presented for a model language with Java-like classes and interfaces, the soundness of the program logic is proven, and a number of illustrative examples are presented

    The Meaning of Memory Safety

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    We give a rigorous characterization of what it means for a programming language to be memory safe, capturing the intuition that memory safety supports local reasoning about state. We formalize this principle in two ways. First, we show how a small memory-safe language validates a noninterference property: a program can neither affect nor be affected by unreachable parts of the state. Second, we extend separation logic, a proof system for heap-manipulating programs, with a memory-safe variant of its frame rule. The new rule is stronger because it applies even when parts of the program are buggy or malicious, but also weaker because it demands a stricter form of separation between parts of the program state. We also consider a number of pragmatically motivated variations on memory safety and the reasoning principles they support. As an application of our characterization, we evaluate the security of a previously proposed dynamic monitor for memory safety of heap-allocated data.Comment: POST'18 final versio
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