Complex Event Recognition (CER) systems detect event occurrences in streaming time-stamped input using predefined event patterns. logic-based approaches are of special interest in CER, since, via Statistical Relationa...
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Epistemic logic Programs (ELPs) extend Answer Set programming (ASP) with epistemic negation and have received renewed interest in recent years. This led to the development of new research and efficient solving systems...
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Epistemic logic Programs (ELPs) extend Answer Set programming (ASP) with epistemic negation and have received renewed interest in recent years. This led to the development of new research and efficient solving systems for ELPs. In practice, ELPs are often written in a modular way, where each module interacts with other modules by accepting sets of facts as input, and passing on sets of facts as output. An interesting question then presents itself: under which conditions can such a module be replaced by another one without changing the outcome, for any set of input facts? This problem is known as uniform equivalence, and has been studied extensively for ASP. For ELPs, however, such an investigation is, as of yet, missing. In this paper, we therefore propose a characterization of uniform equivalence that can be directly applied to the language of state-of-the-art ELP solvers. We also investigate the computational complexity of deciding uniform equivalence for two ELPs, and show that it is on the third level of the polynomial hierarchy.
The paper describes an ongoing effort in developing a declarative system for supporting operators in the Nuclear Power Plant (NPP) control room. The focus is on two modules: diagnosis and explanation of events that ha...
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The paper describes an ongoing effort in developing a declarative system for supporting operators in the Nuclear Power Plant (NPP) control room. The focus is on two modules: diagnosis and explanation of events that happened in NPPs. We describe an Answer Set programming (ASP) representation of an NPP, which consists of declarations of state variables, components, their connections, and rules encoding the plant behavior. We then show how the ASP program can be used to explain the series of events that occurred in the Three Mile Island, Unit 2 (TMI-2) NPP accident, the most severe accident in the USA nuclear power plant operating history. We also describe an explanation module aimed at addressing answers to questions such as "why an event occurs?" or "what should be done?" given the collected data.
Testing algorithms across a wide range of problem instances is crucial to ensure the validity of any claim about one algorithm’s superiority over another. However, when it comes to inference algorithms for probabilis...
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This paper proposes the use of Constraint logicprogramming (CLP) to model SQL queries in a data-independent abstract layer by focusing on some semantic properties for signalling possible errors in such queries. First...
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This paper proposes the use of Constraint logicprogramming (CLP) to model SQL queries in a data-independent abstract layer by focusing on some semantic properties for signalling possible errors in such queries. First, we define a translation from SQL to Datalog, and from Datalog to CLP, so that solving this CLP program will give information about inconsistency, tautology, and possible simplifications. We use different constraint domains which are mapped to SQL types, and propose them to cooperate for improving accuracy. Our approach leverages a deductive system that includes SQL and Datalog, and we present an implementation in this system which is currently being tested in classroom, showing its advantages and differences with respect to other approaches, as well as some performance data.
Answer-set programming (ASP) is an automated problem-solving paradigm specifically suitable for combinatorial search and optimization problems. Such problems can be solved both in theory and also increasingly in pract...
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Answer-set programming (ASP) is an automated problem-solving paradigm specifically suitable for combinatorial search and optimization problems. Such problems can be solved both in theory and also increasingly in practice by ASP technology.
The purpose of this dissertation is to contribute to ASP technology and particularly to the efficiency of ASP solving tools. In more detail, the contributions of this thesis focus on ASP optimization algorithms as well as ASP search algorithms based on so-called lazy-grounding. To these ends, several methods are proposed and shown theoretically and experimentally to have measurable performance increasing potential.
The methods belong to two novel classes of ASP transformations: optimization rewritings, aimed at enhancing optimization performance, and firstorder lazy-normalizations aimed at extending the applicability of lazy-grounding in general. On the topic of transformations, this dissertation moreover presents novel systematic ways to test and verify the correctness of certain types of ASP transformations. These verification methods are distinct in the way they compare programs, which has been designed to reflect the behavior of standard ASP solvers to be as practically relevant as possible. Regarding practical optimization performance, the value of this work is substantial as evidenced by the excellent optimization performance of the proposed techniques in the highly competitive ASP Competition series. In particular, early versions of the techniques attained first place in the optimization track of the sixth edition of the series [56]. Moreover, the included work on lazy-grounding removed an obstacle previously preventing lazy-grounding from being applied to broad classes of programs that are central to the ASP paradigm.
The proceedings contain 27 papers. The special focus in this conference is on programming. The topics include: Exploring Type-Level Bisimilarity towards More Expressive Multiparty Session Types;verifying Visibility-Ba...
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(纸本)9783030449131
The proceedings contain 27 papers. The special focus in this conference is on programming. The topics include: Exploring Type-Level Bisimilarity towards More Expressive Multiparty Session Types;verifying Visibility-Based Weak Consistency;local Reasoning for Global Graph Properties;aneris: A Mechanised logic for Modular Reasoning about Distributed Systems;continualization of Probabilistic Programs With Correction;semantic Foundations for Deterministic Dataflow and Stream Processing;connecting Higher-Order Separation logic to a First-Order Outside World;modular Inference of Linear Types for Multiplicity-Annotated Arrows;RustHorn: CHC-Based Verification for Rust Programs;a First-Order logic with Frames;runners in Action;proving the Safety of Highly-Available Distributed Objects;solving Program Sketches with Large Integer Values;modular Relaxed Dependencies in Weak Memory Concurrency;ARMv8-A System Semantics: Instruction Fetch in Relaxed Architectures;higher-Ranked Annotation Polymorphic Dependency Analysis;ConSORT: Context- and Flow-Sensitive Ownership Refinement Types for Imperative Programs;mixed Sessions;higher-Order Spreadsheets with Spilled Arrays;on the Versatility of Open logical Relations: Continuity, Automatic Differentiation, and a Containment Theorem;constructive Game logic;optimal and Perfectly Parallel Algorithms for On-demand Data-Flow Analysis;concise Read-Only Specifications for Better Synthesis of Programs with Pointers;soundness Conditions for Big-Step Semantics;liberate Abstract Garbage Collection from the Stack by Decomposing the Heap;SMT-Friendly Formalization of the Solidity Memory Model.
We introduce a novel logic-based system for reasoning over data streams, which relies on a framework enabling a tight, fine-tuned interaction between Apache Flink and the I2-DLV system. The architecture allows to take...
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This paper investigates how high school students in an introductory computer science (CS) course approach computing in the logicprogramming (LP) paradigm. This qualitative study shows how novice students operate with...
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This paper investigates how high school students in an introductory computer science (CS) course approach computing in the logicprogramming (LP) paradigm. This qualitative study shows how novice students operate within the LP paradigm while engaging in foundational computing concepts and skills: students are engaged in a cyclical process of abstraction, reasoning, and creating representations of their ideas in code while also being informed by the (procedural) requirements and the revision/debugging process. As these computing concepts and skills are also expected in traditional approaches to introductory K-12 CS courses, this paper asserts that LP is a viable paradigm choice for high school novices.
Formal reasoning about finite sets and cardinality is important for many applications, including software verification, where very often one needs to reason about the size of a given data structure. The Constraint Log...
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