395 research outputs found
Archive and Market Dynamics: (History of) Library, (Digital) Humanities, and âCultural Memory Institutionsâ
This work introduces the idea of memory practices in consumption processes and in market system dynamics through the role of archives and digital practice of archiving. From a historical institutionalism perspective, listed in digital humanities in terms of media archaeology, the historical evolution of the library allows to introduce the notion of archive as: (i) category of objects, standards, classification systems and cataloguing mechanisms (from Science and Technology Studies); (ii) and cultural artefact (aÌ la Foucault). From mnemonic devices (digital archive) mnemonic practices emerge (digital archiving practices) whose collective memories help âto generateâ and âtake shape fromâ markets as mnemonic communities (cultural memory institutions). The work suggests a research agenda on market system dynamics based on different ways of conceiving the mnemonic dimension of social phenomena
CLiFF Notes: Research In Natural Language Processing at the University of Pennsylvania
CLIFF is the Computational Linguists\u27 Feedback Forum. We are a group of students and faculty who gather once a week to hear a presentation and discuss work currently in progress. The \u27feedback\u27 in the group\u27s name is important: we are interested in sharing ideas, in discussing ongoing research, and in bringing together work done by the students and faculty in Computer Science and other departments.
However, there are only so many presentations which we can have in a year. We felt that it would be beneficial to have a report which would have, in one place, short descriptions of the work in Natural Language Processing at the University of Pennsylvania. This report then, is a collection of abstracts from both faculty and graduate students, in Computer Science, Psychology and Linguistics. We want to stress the close ties between these groups, as one of the things that we pride ourselves on here at Penn is the communication among different departments and the inter-departmental work.
Rather than try to summarize the varied work currently underway at Penn, we suggest reading the abstracts to see how the students and faculty themselves describe their work. The report illustrates the diversity of interests among the researchers here, as well as explaining the areas of common interest. In addition, since it was our intent to put together a document that would be useful both inside and outside of the university, we hope that this report will explain to everyone some of what we are about
GPU Computing for Cognitive Robotics
This thesis presents the first investigation of the impact of GPU
computing on cognitive robotics by providing a series of novel experiments in
the area of action and language acquisition in humanoid robots and computer
vision. Cognitive robotics is concerned with endowing robots with high-level
cognitive capabilities to enable the achievement of complex goals in complex
environments. Reaching the ultimate goal of developing cognitive robots will
require tremendous amounts of computational power, which was until
recently provided mostly by standard CPU processors. CPU cores are
optimised for serial code execution at the expense of parallel execution, which
renders them relatively inefficient when it comes to high-performance
computing applications. The ever-increasing market demand for
high-performance, real-time 3D graphics has evolved the GPU into a highly
parallel, multithreaded, many-core processor extraordinary computational
power and very high memory bandwidth. These vast computational resources
of modern GPUs can now be used by the most of the cognitive robotics models
as they tend to be inherently parallel. Various interesting and insightful
cognitive models were developed and addressed important scientific questions
concerning action-language acquisition and computer vision. While they have
provided us with important scientific insights, their complexity and
application has not improved much over the last years. The experimental
tasks as well as the scale of these models are often minimised to avoid
excessive training times that grow exponentially with the number of neurons
and the training data. This impedes further progress and development of
complex neurocontrollers that would be able to take the cognitive robotics
research a step closer to reaching the ultimate goal of creating intelligent
machines. This thesis presents several cases where the application of the GPU
computing on cognitive robotics algorithms resulted in the development of
large-scale neurocontrollers of previously unseen complexity enabling the
conducting of the novel experiments described herein.European Commission Seventh Framework
Programm
Improving Usability in Procedural Modeling
This work presents new approaches and algorithms for procedural modeling geared towards user convenience and improving usability, in order to increase artistsâ productivity. Procedural models create geometry for 3D models from sets of rules. Existing approaches that allow to model trees, buildings, and terrain are reviewed and possible improvements are discussed. A new visual programming language for procedural modeling is discussed, where the user connects operators to visual programs called model graphs. These operators create geometry with textures, assign or evaluate variables or control the sequence of operations. When the user moves control points using the mouse in 3D space, the model graph is executed to change the geometry interactively. Thus, model graphs combine the creativity of freehand modeling with the power of programmed modeling while displaying the program structure more clearly than textbased approaches. Usability is increased as a result of these advantages. Also, an interactive editor for botanical trees is demonstrated. In contrast to previous tree modeling systems, we propose linking rules, parameters and geometry to semantic entities. This has the advantage that problems of associating parameters and instances are completely avoided. When an entity is clicked in the viewport, its parameters are displayed immediately, changes are applied to selected entities, and viewport editing operations are reflected in the parameter set. Furthermore, we store the entities in a hierarchical data structure and allow the user to activate recursive traversal via selection options for all editing operations. The user may choose to apply viewport or parameter changes to a single entity or many entities at once, and only the geometry for the affected entities needs to be updated. The proposed user interface simplifies the modeling process and increases productivity. Interactive editing approaches for 3D models often allow more precise control over a model than a global set of parameters that is used to generate a shape. However, usually scripted procedural modeling generates shapes directly from a fixed set of parameters, and interactive editing mostly uses a fixed set of tools. We propose to use scripts not only to generate models, but also for manipulating the models. A base script would set up the state of an object, and tool scripts would modify that state. The base script and the tool scripts generate geometry when necessary. Together, such a collection of scripts forms a template, and templates can be created for various types of objects. We examine how templates simplify the procedural modeling workflow by allowing for editing operations that are context-sensitive, flexible and powerful at the same time. Many algorithms have been published that produce geometry for fictional landscapes. There are algorithms which produce terrain with minimal setup time, allowing to adapt the level of detail as the user zooms into the landscape. However, these approaches lack plausible river networks, and algorithms that create eroded terrain with river networks require a user to supervise creation and minutes or hours of computation. In contrast to that, this work demonstrates an algorithm that creates terrain with plausible river networks and adaptive level of detail with no more than a few seconds of preprocessing. While the system can be configured using parameters, this text focuses on the algorithm that produces the rivers. However, integrating more tools for user-controlled editing of terrain would be possible.Verbesserung der Usability bei prozeduraler Modellierung Ziel der vorliegenden Arbeit ist es, prozedurale Modellierung durch neue neue AnsĂ€tze und Algorithmen einfacher, bequemer und anwendungsfreundlicher zu machen, und damit die ProduktivitĂ€t der KĂŒnstler zu erhöhen. Diese Anforderungen werden hĂ€ufig unter dem Stichwort Usability zusammengefasst. Prozedurale Modelle spezifizieren 3D-Modelle ĂŒber Regeln. Existierende AnsĂ€tze fĂŒr BĂ€ume, GebĂ€ude und Terrain werden untersucht und es werden mögliche Verbesserungen diskutiert. Eine neue visuelle Programmiersprache fĂŒr prozedurale Modelle wird vorgestellt, bei der Operatoren zu Modellgraphen verschaltet werden. Die Operatoren erzeugen texturierte Geometrie, weisen Variablen zu und werten sie aus, oder sie steuern den Ablauf der Operationen. Wenn der Benutzer Kontrollpunkte im Viewport mit der Maus verschiebt, wird der Modellgraph ausgefĂŒhrt, um interaktiv neue Geometrie fĂŒr das Modell zu erzeugen. Modellgraphen kombinieren die kreativen Möglichkeiten des freihĂ€ndigen Editierens mit der MĂ€chtigkeit der prozeduralen Modellierung. DarĂŒber hinaus sind Modellgraphen eine visuelle Programmiersprache und stellen die Struktur der Algorithmen deutlicher dar als textbasierte Programmiersprachen. Als Resultat dieser Verbesserungen erhöht sich die Usability. Ein interaktiver Editor fĂŒr botanische BĂ€ume wird ebenfalls vorgestellt. Im Gegensatz zu frĂŒheren AnsĂ€tzen schlagen wir vor, Regeln, Parameter und Geometrie zu semantischen EntitĂ€ten zu verschmelzen. Auf diese Weise werden Zuordnungsprobleme zwischen Parametern und deren Instanzen komplett vermieden. Wenn im Viewport eine Instanz angeklickt wird, werden sofort ihre Parameter angezeigt, alle Ănderungen wirken sich direkt auf die betroffenen Instanzen aus, und Ănderungen im Viewport werden sofort in den Parametern reflektiert. DarĂŒber hinaus werden die EntitĂ€ten in einer hierarchischen Datenstruktur gespeichert und alle Ănderungen können rekursiv auf der Hierarchie ausgefĂŒhrt werden. Dem Benutzer werden Selektionsoptionen zur VerfĂŒgung gestellt, ĂŒber die er Ănderungen an den Parametern oder Ănderungen im Viewport an einzelnen oder vielen Instanzen gleichzeitig vornehmen kann. AnschlieĂend muss das System nur die Geometrie der betroffenen Instanzen aktualisieren. Auch hier ist das Ziel, das User Interface möglichst an den BedĂŒrfnissen des Benutzers auszurichten, um Vereinfachungen und eine Erhöhung der ProduktivitĂ€t zu erreichen. Interaktive EditieransĂ€tze fĂŒr 3D-Modelle erlauben hĂ€ufig eine prĂ€zisere Kontrolle ĂŒber ein Modell als ein globaler Parametersatz, der fĂŒr die Erzeugung des Modells genutzt wird. Trotzdem erzeugen prozedurale Modellierskripte ihre Modelle meist direkt aus einem festen Parametersatz, wĂ€hrend interaktive Tools meist mit hartkodierten Operationen arbeiten. Wir schlagen vor, Skripte nicht nur zur Erzeugung der Modelle zu verwenden, sondern auch um die erzeugten Modelle zu editieren. Ein Basisskript soll die Statusinformationen eines Objekts anlegen, wĂ€hrend weitere Skripte diesen Status verĂ€ndern und passende Geometrie erzeugen. Diese Skripte bilden dann ein Template zum Erzeugen einer Klasse von Objekten. Verschiedene Objekttypen können jeweils ihr eigenes Template haben. Wir zeigen, wie Templates den Workflow mit prozeduralen Modellen vereinfachen können, indem Operationen geschaffen werden, die gleichzeitig kontext-sensitiv, mĂ€chtig und flexibel sind. Es existiert eine Reihe von Verfahren, um Geometrie fĂŒr synthetische Landschaften zu erzeugen. Ein Teil der Algorithmen erzeugt Geometrie mit minimaler Vorberechnung und erlaubt es, den Detailgrad der Landschaft interaktiv an die Perspektive anzupassen. Leider fehlen den so erzeugten Landschaften plausible Flussnetze. Algorithmen, die erodiertes Terrain mit Flussnetzen erzeugen, mĂŒssen aufwendig vom Benutzer ĂŒberwacht werden und brauchen Minuten oder Stunden Rechenzeit. Im Gegensatz dazu stellen wir einen Algorithmus vor, der plausible Flussnetze erzeugt, wĂ€hrend sich der Betrachter interaktiv durch die Szene bewegt. Das System kann ĂŒber Parameter gesteuert werden, aber der Fokus liegt auf dem Algorithmus zur Erzeugung der FlĂŒsse. Dennoch wĂ€re es möglich, Tools zum benutzergesteuerten Editieren von Terrain zu integrieren
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The application of software visualization technology to evolutionary computation: a case study in Genetic Algorithms
Evolutionary computation is an area within the field of artificial intelligence that is founded upon the principles of biological evolution. Evolution can be defined as the process of gradual development. Evolutionary algorithms are typically applied as a generic problem solving method, searching a problem space in order to locate good solutions. These solutions are found through an iterative evolutionary search that progresses by means of gradual developments.
In the majority of cases of evolutionary computation the user is not aware of their algorithm's search behaviour. This causes two problems. First, the user has no way of assuring the quality of any solutions found other than to compare the solutions found by the algorithm with any available benchmark solutions or to re-run the algorithm and check if the results can be repeated or improved upon. Second, because the user is unaware of the algorithm's behaviour they have no way of identifying the contribution of the different components of the algorithm and therefore, no direct way of analyzing the algorithm's design and assigning credit to good algorithm components, or locating and improving ineffective algorithm components.
The artificial intelligence and engineering communities have been slow to accept evolutionary computation as a robust problem-solving method because, unlike cased-based systems, rule-based systems or belief networks, they are unable to follow the algorithm's reasoning when locating a set of solutions in the problem space. During an evolutionary algorithm's execution the user may be able to see the results of the search but the search process itself like is a "black box" to the user. It is the search behaviour of evolutionary algorithms that needs to be understood by the user, in order for evolutionary computation to become more accepted within these communities.
The aim of software visualization is to help people understand and use computer software. Software visualization technology has been applied successfully to illustrate a variety of heuristic search algorithms, programming languages and data structures. This thesis adopts software visualization as an approach for illustrating the search behaviour of evolutionary algorithms.
Genetic Algorithms ("GAs") are used here as a specific case study to illustrate how software visualization may be applied to evolutionary computation. A set of visualization requirements are derived from the findings of a GA user study. A number of search space visualization techniques are examined for illustrating the search behaviour of a GA. "Henson," an extendable framework for developing visualization tools for genetic algorithms is presented. Finally, the application of the Henson framework is illustrated by the development of "Gonzo," a visualization tool designed to enable GA users to explore their algorithm's search behaviour.
The contributions made in this thesis extend into the areas of software visualization, evolutionary computation and the psychology of programming. The GA user study presented here is the first and only known study of the working practices of GA users. The search space visualization techniques proposed here have never been applied in this domain before, and the resulting interactive visualizations provide the GA user with a previously unavailable insight into their algorithm's operation
Petri net modelling of a communications protocol
The Petri net is a formal modelling tool applicable to
distributed systems and communication protocols. Two
methods of analysis are applied to formal models of the
"Alternating Bit Protocol".
(i) A timed Petri net model is simulated
to measure protocol performance.
(ii) A modular numeric Petri net model is validated
by reachability analysis.
The simulation and validation tools are programmed in
(i) "C" language and (ii) Prolog. A specification language
"Needle" is developed. It describes the model system as a
hierarchy of modular state transition networks. The model is
searched for all possible event sequences, and the result
displayed as a reachability tree. The specification language
is capable of describing models which execute backwards in
simulation time. The modular numeric Petri net is the basis
of a powerful computer architecture, capable of parsing its
own specification language to build complex models.
Attention is drawn to the similarities between Petri net
theory and quantum mechanics
CLiFF Notes: Research in the Language Information and Computation Laboratory of The University of Pennsylvania
This report takes its name from the Computational Linguistics Feedback Forum (CLIFF), an informal discussion group for students and faculty. However the scope of the research covered in this report is broader than the title might suggest; this is the yearly report of the LINC Lab, the Language, Information and Computation Laboratory of the University of Pennsylvania. It may at first be hard to see the threads that bind together the work presented here, work by faculty, graduate students and postdocs in the Computer Science, Psychology, and Linguistics Departments, and the Institute for Research in Cognitive Science. It includes prototypical Natural Language fields such as: Combinatorial Categorial Grammars, Tree Adjoining Grammars, syntactic parsing and the syntax-semantics interface; but it extends to statistical methods, plan inference, instruction understanding, intonation, causal reasoning, free word order languages, geometric reasoning, medical informatics, connectionism, and language acquisition. With 48 individual contributors and six projects represented, this is the largest LINC Lab collection to date, and the most diverse
Beyond the lens : communicating context through sensing, video, and visualization
Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 101-103).Responding to rapid growth in sensor network deployments that outpaces research efforts to understand or relate the new data streams, this thesis presents a collection of interfaces to sensor network data that encourage open-ended browsing while emphasizing saliency of representation. These interfaces interpret, visualize, and communicate context from sensors, through control panels and virtual environments that synthesize multimodal sensor data into interactive visualizations. This work extends previous efforts in cross-reality to incorporate augmented video as well as complex interactive animations, making use of sensor fusion to saliently represent contextual information to users in a variety of application domains, from building information management to real-time risk assessment to personal privacy. Three applications were developed as part of this work and are discussed here: DoppelLab, an immersive, cross-reality browsing environment for sensor network data; Flurry, an installation that composites video from multiple sources throughout a building in real time, to create an interactive and incorporative view of activity; and Tracking Risk with Ubiquitous Smart Sensing (TRUSS), an ongoing research effort aimed at applying real-time sensing, sensor fusion, and interactive visual analytic interfaces to construction site safety and decision support. Another project in active development, called the Disappearing Act, allows users to remove themselves from a set of live video streams using wearable sensor tags. Though these examples may seem disconnected, they share underlying technologies and research developments, as well as a common set of design principles, which are elucidated in this thesis. Building on developments in sensor networks, computer vision, and graphics, this work aims to create interfaces and visualizations that fuse perspectives, broaden contextual understanding, and encourage exploration of real-time sensor network data.by Gershon Dublon.S.M
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