How Fast Can We Play Tetris Greedily With Rectangular Pieces?

Consider a variant of Tetris played on a board of width $w$ and infinite height, where the pieces are axis-aligned rectangles of arbitrary integer dimensions, the pieces can only be moved before letting them drop, and a row does not disappear once it is full. Suppose we want to follow a greedy strategy: let each rectangle fall where it will end up the lowest given the current state of the board. To do so, we want a data structure which can always suggest a greedy move. In other words, we want a data structure which maintains a set of $O(n)$ rectangles, supports queries which return where to drop the rectangle, and updates which insert a rectangle dropped at a certain position and return the height of the highest point in the updated set of rectangles. We show via a reduction to the Multiphase problem [P\u{a}tra\c{s}cu, 2010] that on a board of width $w=\Theta(n)$, if the OMv conjecture [Henzinger et al., 2015] is true, then both operations cannot be supported in time $O(n^{1/2-\epsilon})$ simultaneously. The reduction also implies polynomial bounds from the 3-SUM conjecture and the APSP conjecture. On the other hand, we show that there is a data structure supporting both operations in $O(n^{1/2}\log^{3/2}n)$ time on boards of width $n^{O(1)}$, matching the lower bound up to a $n^{o(1)}$ factor.Comment: Correction of typos and other minor correction

Directed Emergent Drama

A fully interactive drama, where the player interacts with intelligent Non- Player Characters (NPCs), can revolutionise entertainment, gaming, education, and therapy. Creating such a genuinely interactive drama that is entertaining and gives players a sense of coherency as active participants in the unfolding drama has seen a substantial research effort. Authors have the power to shape dramatised stories for theatre or television at will. Conversely, the authors' ability to shape interactive drama is limited because the drama emerges from players' and NPCs actions during game-play, which significantly limits authoring control. A coherent drama has a recognisable dramatic structure. One philosophy is to use planning algorithms and narrative structures to reduce required authoring. However, planning algorithms are intractable for the large state-spaces intrinsic to interactive dramas, and they have not reduced the authoring problem sufficiently. A more straightforward and computationally feasible method is emergent interactive drama from players' and NPCs' actions. The main difficulty with this approach is maintaining a drama structure and theme, such as a mystery theme or a training scenario, that the player experiences while interacting with the game world. Therefore, it is necessary to impose some form of structure to guide or direct the unfolding drama. The solution introduced in this thesis is to distribute the computation among autonomous actors that are guided by goals and drama structures which a centralised autonomous director agent distributes among the actors, which comprises the following four main elements: a) autonomous rational actor agents that know they are acting and can negotiate dialogues between them to remain realistic while simultaneously progressing the drama, without the player knowing, b) Bayesian network to model the actors reasoning, including beliefs about other actors' mental states c) an autonomous director agent uses "schemas", conceptual structures based on motifs, to guide the actors

‘IMPLICIT CREATION’ – NON-PROGRAMMER CONCEPTUAL MODELS FOR AUTHORING IN INTERACTIVE DIGITAL STORYTELLING

Interactive Digital Storytelling (IDS) constitutes a research field that emerged from several areas of art, creation and computer science. It inquires technologies and possible artefacts that allow ‘highly-interactive’ experiences of digital worlds with compelling stories. However, the situation for story creators approaching ‘highly-interactive’ storytelling is complex. There is a gap between the available technology, which requires programming and prior knowledge in Artificial Intelligence, and established models of storytelling, which are too linear to have the potential to be highly interactive. This thesis reports on research that lays the ground for bridging this gap, leading to novel creation philosophies in future work. A design research process has been pursued, which centred on the suggestion of conceptual models, explaining a) process structures of interdisciplinary development, b) interactive story structures including the user of the interactive story system, and c) the positioning of human authors within semi-automated creative processes. By means of ‘implicit creation’, storytelling and modelling of simulated worlds are reconciled. The conceptual models are informed by exhaustive literature review in established neighbouring disciplines. These are a) creative principles in different storytelling domains, such as screenwriting, video game writing, role playing and improvisational theatre, b) narratological studies of story grammars and structures, and c) principles of designing interactive systems, in the areas of basic HCI design and models, discourse analysis in conversational systems, as well as game- and simulation design. In a case study of artefact building, the initial models have been put into practice, evaluated and extended. These artefacts are a) a conceived authoring tool (‘Scenejo’) for the creation of digital conversational stories, and b) the development of a serious game (‘The Killer Phrase Game’) as an application development. The study demonstrates how starting out from linear storytelling, iterative steps of ‘implicit creation’ can lead to more variability and interactivity in the designed interactive story. In the concrete case, the steps included abstraction of dialogues into conditional actions, and creating a dynamic world model of the conversation. This process and artefact can be used as a model illustrating non-programmer approaches to ‘implicit creation’ in a learning process. Research demonstrates that the field of Interactive Digital Storytelling still has to be further advanced until general creative principles can be fully established, which is a long-term endeavour, dependent upon environmental factors. It also requires further technological developments. The gap is not yet closed, but it can be better explained. The research results build groundwork for education of prospective authors. Concluding the thesis, IDS-specific creative principles have been proposed for evaluation in future work

First steps in the study of cyber-psycho-cognitive operations

Dissertação (mestrado)—Universidade de Brasília, Instituto de Relações Internacionais, Programa de Pós-Graduação em Relações Internacionais, 2019.O presente trabalho é uma análise dos mecanismos informáticos e tecno-comunicacionais envolvidos na articulação de mundos da vida orientados estrategicamente para estimular, prever ou minar o desenvolvimento das condições psico-cognitivas adequadas para a construção e sustento da legitimidade racional de uma autoridade ou ação política. A aplicação de instrumentos “arqueológicos” Foucauldianos ao estudo das narrativas políticas que engendraram e surgiram de “Russiagate” permitiu situar a teoria num contexto histórico e validar a premissa da convergência e incorporação de tendências de agendamento comuns e de práticas típicas de operações psicológicas tradicionais. Contudo, os efeitos tanto da disponibilidade comercial das TICs com capacidade de “deep learning”, quanto da estruturação baseada em conhecimento permitida pela ubiquidade e centralidade econômica dessas tecnologias, tornam o conjunto de mecanismos analisados num fenômeno que merece uma conceptualização e marco investigativo únicos. A obra é uma contribuição a esse empreendimento.This is an analysis of the ICT-based mechanisms involved in the articulation of lifeworlds that are strategically oriented to foster, prevent or undermine the development of psycho-cognitive conditions adequate for the construction or sustainability of an authority’s or a political action’s rational legitimacy. While grounding theory to a historical context, the application of Foucauldian “archeological” instruments to the study of the political narratives giving birth and springing from “Russiagate” also served to validate the premised convergence and incorporation of common agenda-setting trends and practices typical of traditional psychological operations. However, the effects of both the commercial availability of deep-learning ICTs and the cognition-based structuration afforded by their ubiquity and economic centrality set this “dispositif” apart, thereby deserving a unique conceptualization and research framework. This study is a contribution to such endeavor

Air Force Institute of Technology Research Report 2018

This Research Report presents the FY18 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial resources are available and/or provided by a sponsor. In addition, AFIT provides research collaboration and technology transfer benefits to the public through Cooperative Research and Development Agreements (CRADAs). Interested individuals may discuss ideas for new research collaborations, potential CRADAs, or research proposals with individual faculty using the contact information in this document

Structured Approaches for Exploring Interpersonal Relationships in Natural Language Text

Human relationships have long been studied by scientists from domains like sociology, psychology, literature, etc. for understanding people's desires, goals, actions and expected behaviors. In this dissertation we study inter-personal relationships as expressed in natural language text. Modeling inter-personal relationships from text finds application in general natural language understanding, as well as real-world domains such as social networks, discussion forums, intelligent virtual agents, etc. We propose that the study of relationships should incorporate not only linguistic cues in text, but also the contexts in which these cues appear. Our investigations, backed by empirical evaluation, support this thesis, and demonstrate that the task benefits from using structured models that incorporate both types of information. We present such structured models to address the task of modeling the nature of relationships between any two given characters from a narrative. To begin with, we assume that relationships are of two types: cooperative and non-cooperative. We first describe an approach to jointly infer relationships between all characters in the narrative, and demonstrate how the task of characterizing the relationship between two characters can benefit from including information about their relationships with other characters in the narrative. We next formulate the relationship-modeling problem as a sequence prediction task to acknowledge the evolving nature of human relationships, and demonstrate the need to model the history of a relationship in predicting its evolution. Thereafter, we present a data-driven method to automatically discover various types of relationships such as familial, romantic, hostile, etc. Like before, we address the task of modeling evolving relationships but don't restrict ourselves to two types of relationships. We also demonstrate the need to incorporate not only local historical but also global context while solving this problem. Lastly, we demonstrate a practical application of modeling inter-personal relationships in the domain of online educational discussion forums. Such forums offer opportunities for its users to interact and form deeper relationships. With this view, we address the task of identifying initiation of such deeper relationships between a student and the instructor. Specifically, we analyze contents of the forums to automatically suggest threads to the instructors that require their intervention. By highlighting scenarios that need direct instructor-student interactions, we alleviate the need for the instructor to manually peruse all threads of the forum and also assist students who have limited avenues for communicating with instructors. We do this by incorporating the discourse structure of the thread through latent variables that abstractly represent contents of individual posts and model the flow of information in the thread. Such latent structured models that incorporate the linguistic cues without losing their context can be helpful in other related natural language understanding tasks as well. We demonstrate this by using the model for a very different task: identifying if a stated desire has been fulfilled by the end of a story

Menetelmiä ja malleja kielelliseen ja musiikilliseen laskennalliseen luovuuteen

Computational creativity is an area of artificial intelligence that develops algorithms and simulations of creative phenomena, as well as tools for performing creative tasks. In this thesis, we present various computational methods and models of linguistic and musical creativity. The emphasis is on developing methods that are maximally unsupervised, i.e. methods that require a minimal amount of hand-crafted linguistic, world, or domain knowledge. This thesis consists of an introductory part and five original research articles. The introductory part outlines computational creativity as a research field and discusses some of the philosophical foundations underlying the current work. The research articles present specific methods and algorithms for automatic composition of poetry and songs. The first article proposes a corpus-based poetry generation method that relies on statistical language modelling and morphological analysis and synthesis. In the second article, we expand that basic model with constraint programming techniques to handle more aspects of the poetic structure and style. The third article presents a method for mining document-specific word associations and proposes using them in poetry generation to produce poems based, for instance, on a specific news story. The fourth article presents a song composition system that utilises constraint programming to produce songs with matching lyrics and music in a transformational way, i.e. it is able to modify its own search space and preferences. Transformationality of the system is achieved with a metalevel component that can modify the system's internal constraints leading into new conceptual spaces. Finally, the fifth article discusses possibilities of combining personal biosignal measurements, especially electroencephalography, with techniques of computational creativity and presents an art installation called Brain Poetry based on these ideas. The current work relies heavily on the use of unsupervised data mining techniques to automatically build models of specific creative domains such as poetry. The proposed methods and models are flexible and they are to a large extent independent of language and style. Thus, they provide a general framework for computational or synthetic creativity in linguistic and musical domains that can be easily expanded in many ways. Applications of this work include pedagogical tools, computer games, and artistic results.Laskennallinen luovuus on tekoälytutkimuksen osa-alue, joka kehittää algoritmeja ja simulaatioita luovista ilmiöistä sekä työkaluja luovien tehtävien suorittamiseen. Tässä väitöskirjassa esitetään uusia laskennallisia menetelmiä kielellisen ja musiikillisen luovuuden alueella. Väitöskirjatutkimuksen pääpaino on ollut mahdollisimman ohjaamattomien menetelmien kehittämisessä. Toisin sanoen näiden menetelmien tulisi vaatia minimaalinen määrä käsin syötettyä tietoa kielestä, maailmasta tai tietystä erityisalasta. Väitöskirja koostuu johdanto-osasta sekä viidestä alkuperäisestä tutkimusartikkelista. Johdanto-osa esittelee laskennallisen luovuuden tutkimusalana ja käsittelee tärkeimpiä työn taustalla olevia filosofisia kysymyksiä. Tutkimusartikkelit esittelevät spesifejä menetelmiä ja algoritmeja runojen ja laulujen automaattiseen tuottamiseen. Nämä menetelmät perustuvat kielen tilastolliseen mallintamiseen, morfologiseen analyysiin ja synteesiin sekä rajoitelaskentaan. Lisäksi esitetään, kuinka rajoitelaskentaa voidaan hyödyntää laskennallisesti luovan järjestelmän transformationaalisuuden saavuttamiseen. Tällöin järjestelmä kykenee muokkaamaan omaa hakuavaruuttaan ja tavoitteitaan sisäisiä rajoitteitaan muuntelemalla. Viimeisessä artikkelissa käsitellään biosignaalimittausten yhdistämistä laskennallisen luovuuden menetelmiin ja esitellään taideinstallaatio, joka perustuu näihin ajatuksiin. Tehdyssä tutkimuksessa on hyödynnetty erityisesti ohjaamattomia tiedonlouhintamenetelmiä mallien rakentamiseksi luovuutta vaativina pidetyistä alueista, kuten runoudesta. Esitetyt menetelmät ja mallit ovat joustavia ja pitkälti riippumattomia tietystä kielestä tai tyylilajista. Siten ne tarjoavat yleisluontoisen ja helposti laajennettavissa olevan viitekehyksen laskennalliselle kielelliselle ja musiikilliselle luovuudelle. Työn sovelluksiin lukeutuvat muun muassa pedagogiset työkalut, tietokonepelit ja taiteelliset tulokset