ABSTRACT. In this paper, we answer the Role-Based Access Control (RBAC) challenge by showcasing the solution of RBAC components by using JASP, a flexible framework integrating ASP with Java. In JASP the programmer can simply embed ASP code in a Java program without caring about the interaction with the underlying ASP system. This way, it is possible solve seamlessly both tasks suitable for imperative and declarative specification as required by RBAC.

ABSTRACT. The RBAC challenge paper describes a dynamic system for role based access control. In this position paper, we take a theoretical perspective on the problem. The questions we asked ourselves were of the following kind: how much of the RBAC domain can be formally specified in first order logic extended with inductive definitions and aggregates (FO(.))? How much of the RBAC system can be analyzed on the basis of this formal specification? What functionalities of the RBAC system can be executed by applying suitable forms of inference on the formal specification? What forms of inference are needed for that?

ABSTRACT. We are developing a rule-based implementation of a tool to analyse and generate graphs. It is used in the domain of mason's marks. For thousands of years, stonemasons have been inscribing these symbolic signs on dressed stone. Geometrically, mason's marks are line drawings. They consist of a pattern of straight lines, sometimes circles and arcs. We represent mason's marks by connected planar graphs.

Our prototype tool for analysis and generation of graphs is implemented in the rule-based declarative language Constraint Handling Rules (CHR). It features

- a vertex-centric logical graph representation as constraints, - derivation of properties and statistics from graphs, - recognition of (sub)graphs and patterns in a graph, - automatic generation of graphs from given constrained subgraphs, - drawing graphs by visualization using svg graphics

In particular, we started to use the tool to classify and to invent mason's marks. In principe, our tool can be applied to any problem domain that admits a modeling as graphs. The drawing and generation module of our tool is available online at http://chr.informatik.uni-ulm.de/mason.

ABSTRACT. Role-Based Access Control (RBAC) is a popular security policy framework. User access to resources is controlled by roles and privileges. Constraint Handling Rules (CHR) is a rule-based constraint logic language. CHR has been used to implement security policies for trust management systems like RBAC for more than two decades. In this extended abstract, we give some references to these works.

ABSTRACT. Computational cognitive modeling tries to explore cognition through developing detailed, process-based understanding by specifying corresponding computational models.

Currently, computational cognitive modeling architectures as well as the implementations of cognitive models are typically ad-hoc constructs. They lack a formalization from the computer science point of view. This impedes analysis of the models.

In this work, we present how cognitive models can be formalized and analyzed with the help of logic programming in form of Constraint Handling Rules (CHR). We concentrate on confluence analysis of cognitive models in the popular cognitive architecture Adaptive Control of Thought -- Rational (ACT-R).

ABSTRACT. Answer Set Programming (ASP) is a powerful rule-based language for knowledge representation and reasoning that has been developed in the field of logic programming and nonmonotonic reasoning. After many years of basic research, the ASP technology has become mature for the development of significant real-world applications. In particular, the well-known ASP system DLV has undergone an industrial exploitation by a spin-off company called DLVSYSTEM srl, which has led to its successful usage in a number of industry-level applications. The success of DLV for applications development is due also to its endowment with powerful development tools, supporting researchers and software developers that simplify the integration of ASP in real-world applications which usually require to combine logic-based modules within a complete system featuring user interfaces, services etc. In this talk, we first recall the basics of the ASP language. Then, we overview our advanced development tools, and we report on the recent implementation of some challenging industry-level applications of our system.

ABSTRACT. We discuss how rules and constraints might be made easier for more conventional programming. We use a language that extends DistAlgo, which extends Python, and we use the RBAC programming challenge plus distributed RBAC as examples.

ABSTRACT. The world is dynamic, and ASP is not! This is a provocative way to say that ASP is not up to dealing with many complex real-world applications having a dynamic nature, let alone transitions over states, not even mentioning more fine-grained temporal structures.

ABSTRACT. In this paper, we describe the solutions and limitations of implementing the RBAC challenge problem in LogicBlox/LogiQL.

ABSTRACT. We propose a system design principle that explains how to use declarative programming (logic and functional) together with imperative programming. The advantages of declarative programming are well known; they include ease of analysis, verification, testing, optimization, maintenance, upgrading, and distributed implementation. We will not elaborate on these advantages here, but rather focus on what part of the software system should be written declaratively. Declarative programming cannot interface directly with the real world since it does not support common real-world concepts such as physical time, named state, and nondeterminism. Other programming paradigms that support these concepts must therefore be used, such as imperative programming (which contains named state). To optimize the system design, we propose that real-world concepts should only be used where they are needed, namely where the system interfaces with the real world. It follows that a software system should be built completely declaratively except where it interfaces with the real world. We motivate this principle with examples from our research and we give it a precise formal definition.

ABSTRACT. Both software engineers and business people tend to be reluctant to adopt logic-based methods. On the one hand, this may be due to unfamiliarity with ``scary'' logical syntax. To ameliorate this, we developed an API for a state-of-the-art logic system, using only standard Python syntax. On the other hand, logic-based methods might have more impact if they could be used directly by business people. The recent DMN standard that might help in this respect.

ABSTRACT. In this position paper we first describe a classic logic programming approach to the solution of (a portion) of the challenge problem involving RBAC. We use the XSB Tabled Prolog Language and system \cite{xsbmanual-07}, with ideas from Transaction Logic \cite{trans-tcs94xs}. Then we discuss issues that involve what would be required to use such an implementation in a real-world application requiring RBAC functionality. And finally we raise issues about the possible design of a general procedural application programming interface to logic (programming) systems. In analogy to ODBC (Open Data Base Connectivity), what might an OLSC (Open Logic System Connectivity) look like?

ABSTRACT. This document gives an overview of a Picat-based XCSP3 solver, named PicatSAT, submitted to the 2018 XCSP competition. The solver demonstrates the strengths of Picat, a logic-based language, in parsing, modeling, and encoding constraints into SAT.