Task-Level Robot Learning

We are investigating how to program robots so that they learn from experience. Our goal is to develop principled methods of learning that can improve a robot's performance of a wide range of dynamic tasks. We have developed task-level learning that successfully improves a robot's performance of two complex tasks, ball-throwing and juggling. With task- level learning, a robot practices a task, monitors its own performance, and uses that experience to adjust its task-level commands. This learning method serves to complement other approaches, such as model calibration, for improving robot performance.

Computational Structure of Human Language

The central thesis of this report is that human language is NP-complete. That is, the process of comprehending and producing utterances is bounded above by the class NP, and below by NP-hardness. This constructive complexity thesis has two empirical consequences. The first is to predict that a linguistic theory outside NP is unnaturally powerful. The second is to predict that a linguistic theory easier than NP-hard is descriptively inadequate. To prove the lower bound, I show that the following three subproblems of language comprehension are all NP-hard: decide whether a given sound is possible sound of a given language; disambiguate a sequence of words; and compute the antecedents of pronouns. The proofs are based directly on the empirical facts of the language user's knowledge, under an appropriate idealization. Therefore, they are invariant across linguistic theories. (For this reason, no knowledge of linguistic theory is needed to understand the proofs, only knowledge of English.) To illustrate the usefulness of the upper bound, I show that two widely-accepted analyses of the language user's knowledge (of syntactic ellipsis and phonological dependencies) lead to complexity outside of NP (PSPACE-hard and Undecidable, respectively). Next, guided by the complexity proofs, I construct alternate linguisitic analyses that are strictly superior on descriptive grounds, as well as being less complex computationally (in NP). The report also presents a new framework for linguistic theorizing, that resolves important puzzles in generative linguistics, and guides the mathematical investigation of human language.

Preliminary Observations on Program Instability

This white paper reports emerging findings at the end of Phase I of the Lean Aircraft Initiative in the Policy focus group area. Specifically, it provides details about research on program instability. Its objective is to discuss high-level findings detailing: 1) the relative contribution of different factors to a program’s overall instability; 2) the cost impact of program instability on acquisition programs; and 3) some strategies recommended by program managers for overcoming and/or mitigating the negative effects of program instability on their programs. Because this report comes as this research is underway, this is not meant to be a definitive document on the subject. Rather, is it anticipated that this research may potentially produce a number of reports on program instability-related topics. The government managers of military acquisition programs rated annual budget or production rate changes, changes in requirements, and technical difficulties as the three top contributors, respectively, to program instability. When asked to partition actual variance in their program’s planned cost and schedule to each of these factors, it was found that the combined effects of unplanned budget and requirement changes accounted for 5.2% annual cost growth and 20% total program schedule slip. At a rate of approximately 5% annual cost growth from these factors, it is easy to see that even conservative estimates of the cost benefits to be gained from acquisition reforms and process improvements can quickly be eclipsed by the added cost associated with program instability. Program management practices involving the integration of stakeholders from throughout the value chain into the decision making process were rated the most effective at avoiding program instability. The use of advanced information technologies was rated the most effective at mitigating the negative impact of program instability.

The Perception of Subjective Surfaces

It is proposed that subjective contours are an artifact of the perception of natural three-dimensional surfaces. A recent theory of surface interpolation implies that "subjective surfaces" are constructed in the visual system by interpolation between three-dimensional values arising from interpretation of a variety of surface cues. We show that subjective surfaces can take any form, including singly and doubly curved surfaces, as well as the commonly discussed fronto-parallel planes. In addition, it is necessary in the context of computational vision to make explicit the discontinuities, both in depth and in surface orientation, in the surfaces constructed by interpolation. It is proposed that subjective surfaces and subjective contours are demonstrated. The role played by figure completion and enhanced brightness contrast in the determination of subjective surfaces is discussed. All considerations of surface perception apply equally to subjective surfaces.

Complexity of Human Language Comprehension

The goal of this article is to reveal the computational structure of modern principle-and-parameter (Chomskian) linguistic theories: what computational problems do these informal theories pose, and what is the underlying structure of those computations? To do this, I analyze the computational complexity of human language comprehension: what linguistic representation is assigned to a given sound? This problem is factored into smaller, interrelated (but independently statable) problems. For example, in order to understand a given sound, the listener must assign a phonetic form to the sound; determine the morphemes that compose the words in the sound; and calculate the linguistic antecedent of every pronoun in the utterance. I prove that these and other subproblems are all NP-hard, and that language comprehension is itself PSPACE-hard.

Bases documentales para programas de formación de directores escolares.

1. Situar contextualmente la figura del director. 2. Presentar y recomponer el marco teórico en que se inscribe la dirección escolar y analizar conceptos desde la perspectiva de los principales enfoques de la teoría organizacional: bases, aportaciones y dificultades. 3. Analizar el estado actual de la investigación en torno a la dirección escolar. 4. Revisar las publicaciones en castellano. 5. Revisar las publicaciones en otros idiomas. 6. Analizar aquellos aspectos que la investigación y la literatura consideran prioritarios.. Prospectiva histórica del tema en nuestro país y en los países de nuestro entorno cultural.. Se recompone y analiza el corpus teórico en el que se asienta el tema, tanto en España como en otros países. Se establece una amplia revisión de la literatura específica en torno a la figura del director. A continuación, se seleccionan cinco tópicos que se consideran puntuales dentro de su esfera de actuación: cambio y reforma escolar; dirección o animación pedagógica; desarrollo profesional del profesorado; revisión y supervisión escolar; relaciones con la comunidad circundante.. Bibliograf��a en castellano e inglés. Documentos de la base de datos ERIC. Publicaciones relacionadas con el tema y resultados de investigaciones sin publicar.. A través de un análisis comparativo, se intenta perfilar la situación práctica y real del director en España y, por comparación, en el mundo.. 1. La figura del director está sufriendo una revisión que ha de tenerse en cuenta para no anquilosar las escuelas. 2. La posición del director es clave en una serie de cuestiones cruciales para la vida educativa y profesional de la escuela. 3. La función directiva necesita tiempo y autonomía. 4. Sus funciones necesitan de una formación y readecuación constantes. 5. Para la literatura, aunque no para la legislación, se trata de una figura clave, enmarcada en contínuos dilemas, que necesita de mucha ayuda, formación y, sobre todo, redefinición de roles. 6. No puede seguir hablándose del director como término medio: cada director tiene su estilo y sus conductas, su contexto escolar y comunitario y se relaciona con unos profesionales determinados. Hay que tender a ayudar a cada uno de ellos, pero disponiendo una formación en la práctica y dotándole de los instrumentos y habilidades que necesite. 7. Es necesaria una investigación y una mayor preocupación en nuestro país por esta figura. Son muy pocos los libros y publicaciones, en general, que se ocupan de su figura y, cuando lo hacen, es un 'collage' de temas variados que enmascaran la pobreza de posicionamientos.. Se ha perseguido asentar las bases, servir de paso previo, para el desarrollo de un programa universitario serio, sistemático y moderno de formación de directores escolares. No puede caerse hoy en día en la dinámica de repetición de esquemas en una tema tan candente e importante. Hay que partir de unas bases actuales y fundamentadas en una teoría actualizada, una investigación al día y una práctica real..

Nanocrystalline Ge Flash Memories: Electrical Characterization and Trap Engineering

Conventional floating gate non-volatile memories (NVMs) present critical issues for device scalability beyond the sub-90 nm node, such as gate length and tunnel oxide thickness reduction. Nanocrystalline germanium (nc-Ge) quantum dot flash memories are fully CMOS compatible technology based on discrete isolated charge storage nodules which have the potential of pushing further the scalability of conventional NVMs. Quantum dot memories offer lower operating voltages as compared to conventional floating-gate (FG) Flash memories due to thinner tunnel dielectrics which allow higher tunneling probabilities. The isolated charge nodules suppress charge loss through lateral paths, thereby achieving a superior charge retention time. Despite the considerable amount of efforts devoted to the study of nanocrystal Flash memories, the charge storage mechanism remains obscure. Interfacial defects of the nanocrystals seem to play a role in charge storage in recent studies, although storage in the nanocrystal conduction band by quantum confinement has been reported earlier. In this work, a single transistor memory structure with threshold voltage shift, Vth, exceeding ~1.5 V corresponding to interface charge trapping in nc-Ge, operating at 0.96 MV/cm, is presented. The trapping effect is eliminated when nc-Ge is synthesized in forming gas thus excluding the possibility of quantum confinement and Coulomb blockade effects. Through discharging kinetics, the model of deep level trap charge storage is confirmed. The trap energy level is dependent on the matrix which confines the nc-Ge.

Preliminary Observations on Program Instability

This white paper reports emerging findings at the end of Phase I of the Lean Aircraft Initiative in the Policy focus group area. Specifically, it provides details about research on program instability. Its objective is to discuss high-level findings detailing: 1) the relative contribution of different factors to a program’s overall instability; 2) the cost impact of program instability on acquisition programs; and 3) some strategies recommended by program managers for overcoming and/or mitigating the negative effects of program instability on their programs. Because this report comes as this research is underway, this is not meant to be a definitive document on the subject. Rather, is it anticipated that this research may potentially produce a number of reports on program instability-related topics. The government managers of military acquisition programs rated annual budget or production rate changes, changes in requirements, and technical difficulties as the three top contributors, respectively, to program instability. When asked to partition actual variance in their program’s planned cost and schedule to each of these factors, it was found that the combined effects of unplanned budget and requirement changes accounted for 5.2% annual cost growth and 20% total program schedule slip. At a rate of approximately 5% annual cost growth from these factors, it is easy to see that even conservative estimates of the cost benefits to be gained from acquisition reforms and process improvements can quickly be eclipsed by the added cost associated with program instability. Program management practices involving the integration of stakeholders from throughout the value chain into the decision making process were rated the most effective at avoiding program instability. The use of advanced information technologies was rated the most effective at mitigating the negative impact of program instability.

Studies in stoichiometry with compositional data

Geochemical data that is derived from the whole or partial analysis of various geologic materials represent a composition of mineralogies or solute species. Minerals are composed of structured relationships between cations and anions which, through atomic and molecular forces, keep the elements bound in specific configurations. The chemical compositions of minerals have specific relationships that are governed by these molecular controls. In the case of olivine, there is a well-defined relationship between Mn-Fe-Mg with Si. Balances between the principal elements defining olivine composition and other significant constituents in the composition (Al, Ti) have been defined, resulting in a near-linear relationship between the logarithmic relative proportion of Si versus (MgMnFe) and Mg versus (MnFe), which is typically described but poorly illustrated in the simplex. The present contribution corresponds to ongoing research, which attempts to relate stoichiometry and geochemical data using compositional geometry. We describe here the approach by which stoichiometric relationships based on mineralogical constraints can be accounted for in the space of simplicial coordinates using olivines as an example. Further examples for other mineral types (plagioclases and more complex minerals such as clays) are needed. Issues that remain to be dealt with include the reduction of a bulk chemical composition of a rock comprised of several minerals from which appropriate balances can be used to describe the composition in a realistic mineralogical framework. The overall objective of our research is to answer the question: In the cases where the mineralogy is unknown, are there suitable proxies that can be substituted? Kew words: Aitchison geometry, balances, mineral composition, oxides

Avaluació de les emissions de gasos d’ efecte hivernacle a la ciutat de Girona i propostes de reeducació

En els últims 30 anys, la comunitat internacional ha anat agafant consciència dels efectes que pot tenir l’ increment de les emissions de gasos d’ efecte hivernacle (GEH). És per aquest motiu, entre d’ altres que es fan inventaris d’ emissions de GEH a nivell estatal i a gran escala. Aquest projecte té com a principal objectiu determinar i quantificar les emissions de GEH a escala local del municipi de Girona. Per tal de poder dur a terme aquest treball ha calgut buscar metodologies i softwares, que s’ han hagut d’ adaptar a la singularitat que té Girona, sobretot pel que fa al transport. Finalment es fan propostes que s’ adapten a la problemàtica del municipi

Honoris causa

El 18 de novembre de 2008 la Universitat de Girona va investir Eric J. Hobsbawm i Miquel Roca doctors honoris causa en un acte solemne que va aplegar gairebé tres-centes persones. La rectora, Anna M. Geli, va definir aquesta manifestació acadèmica com el “compromís d’acceptar, de manera crítica i constructiva, la transmissió de saber i de coneixement del llegat dels doctors Hobsbawm i Roca Junyent”. Així mateix, va manifestar que ambdós doctors “són part del segle XX” perquè “l’han viscut i l’han explicat” i han contribuït a fer “un món més habitable i a mostrar-nosen les deficiències”

Doctor honoris causa [novembre 2008]

Parlaments de la cerimònia d’investidura llegits el dia 18 de novembre de 2008 a l’Aula Magna de la Universitat de Girona

Luchas indígenas, trayectorias poscoloniales -Américas y Pacífico-

Este texto es único, puesto que se centra en las trayectorias sociales de líderes indígenas de diferentes regiones del mundo, poniendo los actores sociales en el centro del análisis. Igualmente, el libro privilegia, de una manera novedosa, el método etnográfico y da cuenta, sin embargo, de procesos estructurales (la lógica jurídica, política y económica). Así, permite hacer una crítica, a través de la presentación de materiales empíricos muy ricos, de las aproximaciones clásicas en antropología de la problemática indígena. También da cuenta de investigaciones novedosas sobre objetos y terrenos de invitación interdisciplinarios, que permite la convergencia de varias disciplinas (antropología, historia, derecho, relaciones internacionales, sociología). Este texto logra reunir autores de muchas regiones del mundo alrededor de una misma problemática, y logra una aproximación teórica y metodológica al tema. Está dirigido a la comunidad académica nacional e internacional: internacionalistas, antropólogos sociales, politólogos sociales, y, en general, estudiosos de las cuestiones indígenas y raciales.

Manejo interdisciplinario integrado de vida real contra uno multidisciplinario desintegrado para disminuir exceso de peso : Endocare-Bogotá, Colombia

Introducción: la problemática del Sistema Colombiano de Salud, no favorece que los pacientes reciban un manejo interdisciplinario integrado para disminuir su exceso de peso. Metodología: estudio retrospectivo, comparativo y de serie de casos en el período comprendido entre junio de 2006 y febrero de 2009 en el centro de investigación endocrinológica Endocare. Se seleccionaron 62 pacientes (46 mujeres y 16 varones entre 22 y 88 años): 31 pacientes en el grupo interdisciplinario integrado y 31 pacientes en el grupo multidisciplinario desintegrado. Se les realizó un manejo por endocrinología, nutrición y deportología; si recibían y cumplían con las tres valoraciones en Endocare se definían como tratamiento interdisciplinario integrado de lo contrario se definían como tratamiento multidisciplinario desintegrado. Se evaluaron los cambios de peso y de perímetro de cintura logrados por cada paciente durante doce meses. Resultados: se observó una diferencia estadísticamente significativa mediante un análisis Anova de un factor para la reducción de peso, con una media de reducción de -6% (-8 a -3.9%) del manejo integrado comparado con -3.6% (-4.5 a -2.8%) del manejo desintegrado (IC95%,F= 4.58,p= 0.036). También se observó una disminución del perímetro de cintura, con una media de reducción de -8.1% (-10.6 a -5.5%) del manejo integrado comparado con -4.6% (-5.9 a -3.3%) del manejo desintegrado (IC95%,F=4.58,p=0.036), en un seguimiento a doce meses. Se encontró correlación entre disminución de peso y disminución del perímetro de cintura (Pearson=0.455 p=0.044). Discusión: es posible que un manejo interdisciplinario integrado produzca a un año una mayor reducción de exceso de peso y cintura.