Solving finite domain constraint hierarchies by local consistency and tree search.

by Hui Kau Cheung Henry.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 107-112).Abstracts in English and Chinese.Abstract --- p.iiAcknowledgments --- p.iiiChapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- Organizations of the Thesis --- p.2Chapter 2 --- Background --- p.4Chapter 2.1 --- Constraint Satisfaction Problems --- p.4Chapter 2.1.1 --- Local Consistency Algorithm --- p.5Chapter 2.1.2 --- Backtracking Solver --- p.8Chapter 2.1.3 --- The Branch-and-Bound Algorithm --- p.10Chapter 2.2 --- Over-constrained Problems --- p.14Chapter 2.2.1 --- Weighted Constraint Satisfaction Problems --- p.15Chapter 2.2.2 --- Possibilistic Constraint Satisfaction Problems --- p.15Chapter 2.2.3 --- Fuzzy Constraint Satisfaction Problems --- p.16Chapter 2.2.4 --- Partial Constraint Satisfaction Problems --- p.17Chapter 2.2.5 --- Semiring-Based Constraint Satisfaction Problems --- p.18Chapter 2.2.6 --- Valued Constraint Satisfaction Problems --- p.22Chapter 2.3 --- The Theory of Constraint Hierarchies --- p.23Chapter 2.4 --- Related Work --- p.26Chapter 2.4.1 --- An Incremental Hierarchical Constraint Solver --- p.28Chapter 2.4.2 --- Transforming Constraint Hierarchies into Ordinary Con- straint System --- p.29Chapter 2.4.3 --- The SCSP Framework --- p.30Chapter 2.4.4 --- The DeltaStar Algorithm --- p.32Chapter 2.4.5 --- A Plug-In Architecture of Constraint Hierarchy Solvers --- p.34Chapter 3 --- Local Consistency in Constraint Hierarchies --- p.36Chapter 3.1 --- A Reformulation of Constraint Hierarchies --- p.37Chapter 3.1.1 --- Error Indicators --- p.37Chapter 3.1.2 --- A Reformulation of Comparators --- p.38Chapter 3.1.3 --- A Reformulation of Solution Set --- p.40Chapter 3.2 --- Local Consistency in Classical CSPs --- p.41Chapter 3.3 --- Local Consistency in SCSPs --- p.42Chapter 3.4 --- Local Consistency in CHs --- p.46Chapter 3.4.1 --- The Operations of Error Indicator --- p.47Chapter 3.4.2 --- Constraint Hierarchy k-Consistency --- p.49Chapter 3.4.3 --- A Comparsion between CHAC and PAC --- p.50Chapter 3.4.4 --- The CHAC Algorithm --- p.52Chapter 3.4.5 --- Time and Space Complexities of the CHAC Algorithm --- p.53Chapter 3.4.6 --- Correctness of the CHAC Algorithm --- p.56Chapter 4 --- A Consistency-Based Finite Domain Constraint Hierarchy Solver --- p.59Chapter 4.1 --- The Branch-and-Bound CHAC Solver --- p.59Chapter 4.2 --- Correctness of the Branch-and-Bound CHAC Solver --- p.61Chapter 4.3 --- An Example Execution Trace --- p.64Chapter 4.4 --- Experiments and Results --- p.66Chapter 4.4.1 --- Experimental Setup --- p.68Chapter 4.4.2 --- The First Experiment --- p.71Chapter 4.4.3 --- The Second Experiment --- p.94Chapter 5 --- Concluding Remarks --- p.103Chapter 5.1 --- Summary and Contributions --- p.103Chapter 5.2 --- Future Work --- p.104Bibliography --- p.10

Algorithmic composition of music in real-time with soft constraints

Music has been the subject of formal approaches for a long time, ranging from Pythagoras’ elementary research on tonal systems to J. S. Bach’s elaborate formal composition techniques. Especially in the 20th century, much music was composed based on formal techniques: Algorithmic approaches for composing music were developed by composers like A. Schoenberg as well as in the scientific area. So far, a variety of mathematical techniques have been employed for composing music, e.g. probability models, artificial neural networks or constraint-based reasoning. In the recent time, interactive music systems have become popular: existing songs can be replayed with musical video games and original music can be interactively composed with easy-to-use applications running e.g. on mobile devices. However, applications which algorithmically generate music in real-time based on user interaction are mostly experimental and limited in either interactivity or musicality. There are many enjoyable applications but there are also many opportunities for improvements and novel approaches. The goal of this work is to provide a general and systematic approach for specifying and implementing interactive music systems. We introduce an algebraic framework for interactively composing music in real-time with a reasoning-technique called ‘soft constraints’: this technique allows modeling and solving a large range of problems and is suited particularly well for problems with soft and concurrent optimization goals. Our framework is based on well-known theories for music and soft constraints and allows specifying interactive music systems by declaratively defining ‘how the music should sound’ with respect to both user interaction and musical rules. Based on this core framework, we introduce an approach for interactively generating music similar to existing melodic material. With this approach, musical rules can be defined by playing notes (instead of writing code) in order to make interactively generated melodies comply with a certain musical style. We introduce an implementation of the algebraic framework in .NET and present several concrete applications: ‘The Planets’ is an application controlled by a table-based tangible interface where music can be interactively composed by arranging planet constellations. ‘Fluxus’ is an application geared towards musicians which allows training melodic material that can be used to define musical styles for applications geared towards non-musicians. Based on musical styles trained by the Fluxus sequencer, we introduce a general approach for transforming spatial movements to music and present two concrete applications: the first one is controlled by a touch display, the second one by a motion tracking system. At last, we investigate how interactive music systems can be used in the area of pervasive advertising in general and how our approach can be used to realize ‘interactive advertising jingles’.Musik ist seit langem Gegenstand formaler Untersuchungen, von Phytagoras‘ grundlegender Forschung zu tonalen Systemen bis hin zu J. S. Bachs aufwändigen formalen Kompositionstechniken. Vor allem im 20. Jahrhundert wurde vielfach Musik nach formalen Methoden komponiert: Algorithmische Ansätze zur Komposition von Musik wurden sowohl von Komponisten wie A. Schoenberg als auch im wissenschaftlichem Bereich entwickelt. Bislang wurde eine Vielzahl von mathematischen Methoden zur Komposition von Musik verwendet, z.B. statistische Modelle, künstliche neuronale Netze oder Constraint-Probleme. In der letzten Zeit sind interaktive Musiksysteme populär geworden: Bekannte Songs können mit Musikspielen nachgespielt werden, und mit einfach zu bedienenden Anwendungen kann man neue Musik interaktiv komponieren (z.B. auf mobilen Geräten). Allerdings sind die meisten Anwendungen, die basierend auf Benutzerinteraktion in Echtzeit algorithmisch Musik generieren, eher experimentell und in Interaktivität oder Musikalität limitiert. Es gibt viele unterhaltsame Anwendungen, aber ebenso viele Möglichkeiten für Verbesserungen und neue Ansätze. Das Ziel dieser Arbeit ist es, einen allgemeinen und systematischen Ansatz zur Spezifikation und Implementierung von interaktiven Musiksystemen zu entwickeln. Wir stellen ein algebraisches Framework zur interaktiven Komposition von Musik in Echtzeit vor welches auf sog. ‚Soft Constraints‘ basiert, einer Methode aus dem Bereich der künstlichen Intelligenz. Mit dieser Methode ist es möglich, eine große Anzahl von Problemen zu modellieren und zu lösen. Sie ist besonders gut geeignet für Probleme mit unklaren und widersprüchlichen Optimierungszielen. Unser Framework basiert auf gut erforschten Theorien zu Musik und Soft Constraints und ermöglicht es, interaktive Musiksysteme zu spezifizieren, indem man deklarativ angibt, ‚wie sich die Musik anhören soll‘ in Bezug auf sowohl Benutzerinteraktion als auch musikalische Regeln. Basierend auf diesem Framework stellen wir einen neuen Ansatz vor, um interaktiv Musik zu generieren, die ähnlich zu existierendem melodischen Material ist. Dieser Ansatz ermöglicht es, durch das Spielen von Noten (nicht durch das Schreiben von Programmcode) musikalische Regeln zu definieren, nach denen interaktiv generierte Melodien an einen bestimmten Musikstil angepasst werden. Wir präsentieren eine Implementierung des algebraischen Frameworks in .NET sowie mehrere konkrete Anwendungen: ‚The Planets‘ ist eine Anwendung für einen interaktiven Tisch mit der man Musik komponieren kann, indem man Planetenkonstellationen arrangiert. ‚Fluxus‘ ist eine Anwendung, die sich an Musiker richtet. Sie erlaubt es, melodisches Material zu trainieren, das wiederum als Musikstil in Anwendungen benutzt werden kann, die sich an Nicht-Musiker richten. Basierend auf diesen trainierten Musikstilen stellen wir einen generellen Ansatz vor, um räumliche Bewegungen in Musik umzusetzen und zwei konkrete Anwendungen basierend auf einem Touch-Display bzw. einem Motion-Tracking-System. Abschließend untersuchen wir, wie interaktive Musiksysteme im Bereich ‚Pervasive Advertising‘ eingesetzt werden können und wie unser Ansatz genutzt werden kann, um ‚interaktive Werbejingles‘ zu realisieren

FLACOS’08 Workshop proceedings

The 2nd Workshop on Formal Languages and Analysis of Contract-Oriented Software (FLACOS’08) is held in Malta. The aim of the workshop is to bring together researchers and practitioners working on language-based solutions to contract-oriented software development. The workshop is partially funded by the Nordunet3 project “COSoDIS” (Contract-Oriented Software Development for Internet Services) and it attracted 25 participants. The program consists of 4 regular papers and 10 invited participant presentations

Knowledge compilation for online decision-making : application to the control of autonomous systems = Compilation de connaissances pour la décision en ligne : application à la conduite de systèmes autonomes

La conduite de systèmes autonomes nécessite de prendre des décisions en fonction des observations et des objectifs courants : cela implique des tâches à effectuer en ligne, avec les moyens de calcul embarqués. Cependant, il s'agit généralement de tâches combinatoires, gourmandes en temps de calcul et en espace mémoire. Réaliser ces tâches intégralement en ligne dégrade la réactivité du système ; les réaliser intégralement hors ligne, en anticipant toutes les situations possibles, nuit à son embarquabilité. Les techniques de compilation de connaissances sont susceptibles d'apporter un compromis, en déportant au maximum l'effort de calcul avant la mise en situation du système. Ces techniques consistent à traduire un problème dans un certain langage, fournissant une forme compilée de ce problème, dont la résolution est facile et la taille aussi compacte que possible. La traduction peut être très longue, mais n'est effectuée qu'une seule fois, hors ligne. Il existe de nombreux langages-cible de compilation, notamment le langage des diagrammes de décision binaires (BDDs), qui ont été utilisés avec succès dans divers domaines (model-checking, configuration, planification). L'objectif de la thèse était d'étudier l'application de la compilation de connaissances à la conduite de systèmes autonomes. Nous nous sommes intéressés à des problèmes réels de planification, qui impliquent souvent des variables continues ou à grand domaine énuméré (temps ou mémoire par exemple). Nous avons orienté notre travail vers la recherche et l'étude de langages-cible de compilation assez expressifs pour permettre de représenter de tels problèmes.Controlling autonomous systems requires to make decisions depending on current observations and objectives. This involves some tasks that must be executed online-with the embedded computational power only. However, these tasks are generally combinatory; their computation is long and requires a lot of memory space. Entirely executing them online thus compromises the system's reactivity. But entirely executing them offline, by anticipating every possible situation, can lead to a result too large to be embedded. A tradeoff can be provided by knowledge compilation techniques, which shift as much as possible of the computational effort before the system's launching. These techniques consists in a translation of a problem into some language, obtaining a compiled form of the problem, which is both easy to solve and as compact as possible. The translation step can be very long, but it is only executed once, and offline. There are numerous target compilation languages, among which the language of binary decision diagrams (BDDs), which have been successfully used in various domains of artificial intelligence, such as model-checking, configuration, or planning. The objective of the thesis was to study how knowledge compilation could be applied to the control of autonomous systems. We focused on realistic planning problems, which often involve variables with continuous domains or large enumerated domains (such as time or memory space). We oriented our work towards the search for target compilation languages expressive enough to represent such problems

Foundations of Software Science and Computation Structures

This open access book constitutes the proceedings of the 23rd International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The 31 regular papers presented in this volume were carefully reviewed and selected from 98 submissions. The papers cover topics such as categorical models and logics; language theory, automata, and games; modal, spatial, and temporal logics; type theory and proof theory; concurrency theory and process calculi; rewriting theory; semantics of programming languages; program analysis, correctness, transformation, and verification; logics of programming; software specification and refinement; models of concurrent, reactive, stochastic, distributed, hybrid, and mobile systems; emerging models of computation; logical aspects of computational complexity; models of software security; and logical foundations of data bases.

Computer Aided Verification

This open access two-volume set LNCS 10980 and 10981 constitutes the refereed proceedings of the 30th International Conference on Computer Aided Verification, CAV 2018, held in Oxford, UK, in July 2018. The 52 full and 13 tool papers presented together with 3 invited papers and 2 tutorials were carefully reviewed and selected from 215 submissions. The papers cover a wide range of topics and techniques, from algorithmic and logical foundations of verification to practical applications in distributed, networked, cyber-physical, and autonomous systems. They are organized in topical sections on model checking, program analysis using polyhedra, synthesis, learning, runtime verification, hybrid and timed systems, tools, probabilistic systems, static analysis, theory and security, SAT, SMT and decisions procedures, concurrency, and CPS, hardware, industrial applications

Probabilistic Inference Using Partitioned Bayesian Networks:Introducing a Compositional Framework

Probability theory offers an intuitive and formally sound way to reason in situations that involve uncertainty. The automation of probabilistic reasoning has many applications such as predicting future events or prognostics, providing decision support, action planning under uncertainty, dealing with multiple uncertain measurements, making a diagnosis, and so forth. Bayesian networks in particular have been used to represent probability distributions that model the various applications of uncertainty reasoning. However, present-day automated reasoning approaches involving uncertainty struggle when models increase in size and complexity to fit real-world applications.In this thesis, we explore and extend a state-of-the-art automated reasoning method, called inference by Weighted Model Counting (WMC), when applied to increasingly complex Bayesian network models. WMC is comprised of two distinct phases: compilation and inference. The computational cost of compilation has limited the applicability of WMC. To overcome this limitation we have proposed theoretical and practical solutions that have been tested extensively in empirical studies using real-world Bayesian network models.We have proposed a weighted variant of OBDDs, called Weighted Positive Binary Decision Diagrams (WPBDD), which in turn is based on the new notion of positive Shannon decomposition. WPBDDs are particularly well suited to represent discrete probabilistic models. The conciseness of WPBDDs leads to a reduction in the cost of probabilistic inference.We have introduced Compositional Weighted Model Counting (CWMC), a language-agnostic framework for probabilistic inference that partitions a Bayesian network into subproblems. These subproblems are then compiled and subsequently composed in order to perform inference. This approach significantly reduces the cost of compilation, yet increases the cost of inference. The best results are obtained by seeking a partitioning that allows compilation to (barely) become feasible, but no more, as compilation cost can be amortized over multiple inference queries.Theoretical concepts have been implemented in a readily available open-source tool called ParaGnosis. Further implementational improvements have been found through parallelism, by exploiting independencies that are introduced by CWMC. The proposed methods combined push the boundaries of WMC, allowing this state-of-the-art method to be used on much larger models than before

Programming Languages and Systems

This open access book constitutes the proceedings of the 31st European Symposium on Programming, ESOP 2022, which was held during April 5-7, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 21 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. They deal with fundamental issues in the specification, design, analysis, and implementation of programming languages and systems

Programming Languages and Systems

This open access book constitutes the proceedings of the 30th European Symposium on Programming, ESOP 2021, which was held during March 27 until April 1, 2021, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2021. The conference was planned to take place in Luxembourg and changed to an online format due to the COVID-19 pandemic. The 24 papers included in this volume were carefully reviewed and selected from 79 submissions. They deal with fundamental issues in the specification, design, analysis, and implementation of programming languages and systems