Towards a proof of the decidability of the momentary stagnation of the growth function of D0L systems

This is the published version of a work that was accepted for publication in Theoretical Computer Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Theoretical Computer Science, 341, 1–3, (2005) DOI: 10.1016/j.tcs.2005.05.002This paper proves the decidability of several problems in the theory of HD 0L, D0L and PD 0L systems, some of which that have been proved before but are now proved in a different way. First, the paper tackles the decidability of the nilpotency of HD 0L systems and the infinitude of PD 0L languages. Then, we prove the decidability of the problem of momentary stagnation of the growth function of PD 0L systems. Finally, we suggest a way to solve the decidability of the momentary stagnation of the growth function of D0L systems, proving the decidability of the infinitude of HD 0L as a trivial consequence.This paper has been partially sponsored by the UPV/EHU project number 9/upv 00003.230-13707/2001. This paper has been partially sponsored by the Spanish Ministry of Science and Technology (MCYT) project number TIC2002-01948

The generating function of the number of subpatterns of a DOL sequence

AbstractThe generating function of the number of subpatterns of a DOL sequence is shown to be rational. The computation of the generating function is based on a recursion formula which expresses this function by the generating functions of subpatterns of smaller length and by the Magnus transform of the homomorphism

Proseduraalisen tietomallintamisen käyttöönotto kaupunkisuunnittelussa

This thesis examines procedural modeling as a tool for urban plan creation. Procedural modeling historically has been used for 3D visualization of natural features, but with the release of the soft-ware CityEngine in 2008 the technology can easily be adopted also in problem domains dealing with urban environments. The study begins with a requirement analysis conducted to explore the needs urban planning imposes on the technology, based on which a functional procedural modeling production system is built using the CityEngine platform and its Computer Generated Architecture (CGA) scripting language. A solution is presented to the problem of control in procedural generation methods by introducing the concept of a selectable “Level of Control” and how its implementation in the produced system enables the planner to flexibly assume the necessary amount of control over the generated model. The finished product is then compared against the presented requirements of accuracy, efficiency, ease of use, high visual qualities, and advanced analytical capabilities. The efficiency of the system measured as the ratio between user interactions (mouse clicks and keystrokes) and modeling output in the setting of the assessment is found out to be two to three times greater than the efficiency of a more established manual modeling software. The technology as demonstrated through the produced system is concluded to be especially suitable for preliminary land use studies estimating the building potentials of extensive land areas. Directions for future research with potential to expand the applicability of the technology are discussed.Tässä diplomityössä tutkitaan proseduraalista mallintamista kaupunkisuunnittelun työvälineenä. Proseduraalista mallintamista on historiallisesti käytetty luonnonmuotojen 3D-visualisoimiseen, mutta vuonna 2008 julkaistu CityEngine-ohjelma mahdollistaa teknologian helpon käyttöönoton myös rakennettua ympäristöä koskevissa aihepiireissä. Tutkielma alkaa analyysillä kaupunkisuunnittelun teknologiaan kohdistamista vaatimuksista, joiden perusteella rakennetaan CityEngineen ja sen Computer Generated Architecture (CGA) ohjel-mointikieleen perustuva proseduraalinen mallinnusjärjestelmä. Ratkaisuna proseduraaliseen mallintamiseen liittyvään kontrollin problematiikkaan esitellään käsite valittavasta ”kontrollitasosta”, ja kuinka sen implementaatio toteutetussa järjestelmässä mahdollistaa suunnittelijan ottaa joustavasti tarpeellisen määrän kontrollia generoitavan mallin suhteen. Valmista tuotetta verrataan esitettyihin tarkkuuden, tehokkuuden, käytön helppouden, korkealaatuisen visuaalisuuden, sekä kehittyneen analytiikan vaatimuksiin. Järjestelmän tehokkuus mitattuna käyttäjäinteraktioiden (hiiren klikkaukset ja näppäimistön painallukset) ja tuotetun mallin suhteena mittauksen asetelmassa on kahdesta kolmeen kertaa suurempi kuin vakiintuneemman manuaalisen mallinnusohjelman tehokkuus. Proseduraalisen mallintamisen, sellaisena kuin se tuotetussa järjestelmässä on implementoitu, todetaan olevan erityisen sopiva alustavien rakentamisen määrää laajoille alueille haarukoivien maankäyttötarkastelujen tuottamiseen. Työn lopuksi käsitellään teknologian käyttöaluetta laajentavia tutkimussuuntia

Entwurf und Implementation einer auf Graph-Grammatiken beruhenden Sprache zur Funktions-Struktur-Modellierung von Pflanzen

Increasing biological knowledge requires more and more elaborate methods to translate the knowledge into executable model descriptions, and increasing computational power allows to actually execute these descriptions. Such a simulation helps to validate, extend and question the knowledge. For plant modelling, the well-established formal description language of Lindenmayer systems reaches its limits as a method to concisely represent current knowledge and to conveniently assist in current research. On one hand, it is well-suited to represent structural and geometric aspects of plant models - of which units is a plant composed, how are these connected, what is their location in 3D space -, but on the other hand, its usage to describe functional aspects - what internal processes take place in the plant structure, how does this interact with the structure - is not as convenient as desirable. This can be traced back to the underlying representation of structure as a linear chain of units, while the intrinsic nature of the structure is a tree or even a graph. Therefore, we propose to use graphs and graph grammars as a basis for plant modelling which combines structural and functional aspects. In the first part of this thesis, we develop the necessary theoretical framework. Starting with a presentation of the state of the art concerning Lindenmayer systems and graph grammars, we develop the formalism of relational growth grammars as a variant of graph grammars. We show that this formalism has a natural embedding of Lindenmayer systems which keeps all relevant properties, but represents branched structures directly as axial trees and not as linear chains with indirect encoding of branches. In the second part, we develop the main practical result, the XL programming language as an extension of the Java programming language by very general rule-based features. Short examples illustrate the application of the new language features. We describe the built-in pattern matching algorithm of the implemented run-time system for the XL programming language, and we sketch a possible implementation of an XL compiler. The third part is an application of relational growth grammars and the XL programming language. We show how the general XL interfaces can be customized for relational growth grammars. On top of this customization, several examples from a variety of disciplines demonstrate the usefulness of the developed formalism and language to describe plant growth, especially functional-structural plant models, but also artificial life, architecture or interactive games. Some examples operate on custom graphs like XML DOM trees or scene graphs of commercial 3D modellers, while the majority uses the 3D modelling platform GroIMP, a software developed in conjunction with this thesis. The appendix gives an overview of the GroIMP software. The practical usage of its plug-in for relational growth grammars is also illustrated.Das zunehmende Wissen über biologische Prozesse verlangt nach geeigneten Methoden, es in ausführbare Modelle zu übersetzen, und die zunehmende Rechenleistung der Computer ermöglicht es, diese Modelle auch tatsächlich auszuführen. Solche Simulationen dienen zur Validierung, Erweiterung und Hinterfragung des Wissens. Speziell für die Pflanzenmodellierung wurden Lindenmayer-Systeme mit Erfolg eingesetzt, jedoch stoßen diese bei aktuellen Modellierungsproblemen und Forschungsvorhaben an ihre Grenzen. Zwar sind sie gut geeignet, Pflanzenstruktur und Geometrie abzubilden - aus welchen Einheiten setzt sich eine Pflanze zusammen, wie sind diese verbunden, wie ist ihre räumliche Lage -, aber die lineare Datenstruktur erschwert die Integration von Funktionsmodellen, welche Prozesse innerhalb der verzweigten Struktur und des beanspruchten Raumes beschreiben. Daher wird in dieser Arbeit vorgeschlagen, anstelle der linearen Stuktur Graphen und Graph-Grammatiken als Grundlage für die kombinierte Funktions-Struktur-Modellierung von Pflanzen zu verwenden. Im ersten Teil der Dissertation wird der theoretische Unterbau entwickelt. Nach einer Vorstellung des aktuellen Wissensstandes auf dem Gebiet der Lindenmayer-Systeme und Graph-Grammatiken werden relationale Wachstumsgrammatiken eingeführt, die auf bekannten Mechanismen für parallele Graph-Grammatiken aufbauen und Lindenmayer-Systeme als Spezialfall enthalten, dabei jedoch verzweigte Strukturen direkt als axiale Bäume darstellen. Zur praktischen Anwendung wird im zweiten Teil die Programmiersprache XL entwickelt, die Java um allgemein gehaltene Sprachkonstrukte für Graph-Grammatiken erweitert. Kurze Beispiele zeigen die Anwendung der neuen Sprachmerkmale. Der Algorithmus zur Mustersuche wird erläutert, und die Implementation des XL-Compilers wird vorgestellt. Im dritten Teil werden mögliche Anwendungen relationaler Wachstumsgrammatiken aufgezeigt. Dazu werden zunächst die allgemeinen XL-Schnittstellen für relationale Wachstumsgrammatiken konkretisiert, um dieses System dann für Modelle aus verschiedenen Bereichen zu nutzen, darunter Funktions-Struktur-Modelle von Pflanzen, Künstliches Leben, Architektur und interaktive Spiele. Einige Beispiele nutzen spezifische Graphen wie XML-DOM-Bäume oder Szenengraphen kommerzieller 3D-Modellierprogramme, aber der überwiegende Teil baut auf der 3D-Plattform GroIMP auf, die zusammen mit dieser Dissertation entwickelt wurde. Im Anhang wird die Software GroIMP kurz vorgestellt und ihre praktische Anwendung für relationale Wachstumsgrammatiken erläutert

Ecologically sustainable forest management in Victoria : existing regulation and future directions

The Sustainable Forests (Timber) Act 2004 (Vic) was designed as a framework for ecologically sustainable forest management (ESFM) of Victorian public forestry. It includes the principles of ecologically sustainable development (ESD). These principles are included in a range of natural resource management and conservation Acts around Australia. A separate regulatory framework applied to private forest management is also designed to support sustainable forest management. This study examines both the public and private sector forestry management in Victoria to appreciate the extent to which the existing framework for ESFM addresses the ESD principles. A critical realist research paradigm is adopted via regulatory theory, using four filtering mechanisms to assess the effectiveness of the current framework, including measuring and monitoring, compliance, ESD balance and governance standards. The thesis reports on two studies, that being public and private forestry. Within the two Victorian studies, an organisational perspective is also provided by way of analysis of the strategies and roles of VicForests (public) and Hancock Victorian Plantation Pty Ltd (HVP - the largest private forestry entity in Victoria.) Referring to regulatory theory and empirical evidence, an adapted regulatory mode using a precautionary risk management structure is proposed. This approach required application of sustainability criteria and indicators currently used to meet reporting obligations. The adapted regulation that resulted uses trigger points for an adaptive management response regulatory model. This model identifies the responsible parties for determining sustainability objectives and applying principles of ecologically sustainable development, data collection processes and review of data against criteria in order to activate the trigger and the resultant adaptive response. The end result is to evaluate data in order to determine when and how to activate a trigger for an adaptive response which is proportionate to the level of risk. The adapted model emphasises accountability and transparency, utilising bespoke sustainability criteria and indicators to inform each stage of the regulatory process. This model demonstrates the importance of using criteria and indicators in natural resource regulation, and that simply inserting sustainability principles and objectives into regulation is not sufficient to achieve worthwhile sustainability outcomes. This thesis concludes by evaluating this alternative model for implications to practice, policy and future research and its potential use in other resource sectors. Implications are drawn that this adapted framework could be a transferable template for other forestry jurisdictions and (with modifications) other natural resource sectorsDoctor of Philosoph

On Musical Self-Similarity : Intersemiosis as Synecdoche and Analogy

Self-similarity, a concept borrowed from mathematics, is gradually becoming a keyword in musicology. Although a polysemic term, self-similarity often refers to the multi-scalar feature repetition in a set of relationships, and it is commonly valued as an indication for musical ‘coherence’ and ‘consistency’. In this study, Gabriel Pareyon presents a theory of musical meaning formation in the context of intersemiosis, that is, the translation of meaning from one cognitive domain to another cognitive domain (e.g. from mathematics to music, or to speech or graphic forms). From this perspective, the degree of coherence of a musical system relies on a synecdochic intersemiosis: a system of related signs within other comparable and correlated systems. The author analyzes the modalities of such correlations, exploring their general and particular traits, and their operational bounds. Accordingly, the notion of analogy is used as a rich concept through its two definitions quoted by the Classical literature—proportion and paradigm, enormously valuable in establishing measurement, likeness and affinity criteria. At the same time, original arguments by Benoît B. Mandelbrot (1924–2010) are revised, alongside a systematic critique of the literature on the subject. In fact, connecting Charles S. Peirce’s ‘synechism’ with Mandelbrot’s ‘fractality’ is one of the main developments of the present study

Non-Standard Sound Synthesis with Dynamic Models

Full version unavailable due to 3rd party copyright restrictions.This Thesis proposes three main objectives: (i) to provide the concept of a new generalized non-standard synthesis model that would provide the framework for incorporating other non-standard synthesis approaches; (ii) to explore dynamic sound modeling through the application of new non-standard synthesis techniques and procedures; and (iii) to experiment with dynamic sound synthesis for the creation of novel sound objects. In order to achieve these objectives, this Thesis introduces a new paradigm for non-standard synthesis that is based in the algorithmic assemblage of minute wave segments to form sound waveforms. This paradigm is called Extended Waveform Segment Synthesis (EWSS) and incorporates a hierarchy of algorithmic models for the generation of microsound structures. The concepts of EWSS are illustrated with the development and presentation of a novel non-standard synthesis system, the Dynamic Waveform Segment Synthesis (DWSS). DWSS features and combines a variety of algorithmic models for direct synthesis generation: list generation and permutation, tendency masks, trigonometric functions, stochastic functions, chaotic functions and grammars. The core mechanism of DWSS is based in an extended application of Cellular Automata. The potential of the synthetic capabilities of DWSS is explored in a series of Case Studies where a number of sound object were generated revealing (i) the capabilities of the system to generate sound morphologies belonging to other non-standard synthesis approaches and, (ii) the capabilities of the system of generating novel sound objects with dynamic morphologies. The introduction of EWSS and DWSS is preceded by an extensive and critical overview on the concepts of microsound synthesis, algorithmic composition, the two cultures of computer music, the heretical approach in composition, non- standard synthesis and sonic emergence along with the thorough examination of algorithmic models and their application in sound synthesis and electroacoustic composition. This Thesis also proposes (i) a new definition for “algorithmic composition”, (ii) the term “totalistic algorithmic composition”, and (iii) four discrete aspects of non-standard synthesis