23 research outputs found
Dynamic algorithm configuration by reinforcement learning
No full textThe performance of algorithms, be it in the domain of machine learning, hard combinatorial problem solving or AI in general depends on their many parameters. Tuning an algorithm manually, however, is error-prone and very time-consuming. Many, if not most, algorithms are iterative in nature. Thus, they traverse a potentially diverse solution space, which might require different parameter settings at different stages to behave optimally. Further, algorithms are often used for solving a diverse set of problem instances, which by themselves might require different parameters. Taking all of this into account is infeasible for a human designer. Automated methods have therefore been proposed to mitigate human errors and minimize manual efforts. While such meta-algorithmic methods have shown large successes, there is still a lot of untapped potentials as prior approaches typically only consider configurations that do not change during an algorithm’s run or do not adapt to the problem instance.In this dissertation, we present the first framework that is capable of dynamicallyconfiguring algorithms, in other words, capable of adapting configurations to the problem instance at hand during an algorithm’s solving process. To this end, we model the dynamic algorithm configuration (DAC) problem as a contextual Markov decision process. This enables us to learn dynamic configuration policies in a data-driven way by means of reinforcement learning.We empirically demonstrate the effectiveness of our framework on a diverse set of problem settings consisting of artificial benchmarks, evolutionary algorithms, AI planning systems, as well as deep learning. We show that DAC outperforms previous meta-algorithmic approaches. Building on these successes, we formulate the first standardized interface for dynamic configuration and an extensive benchmark to facilitate reproducibility and lower the barrier of entry for new researchers into this novel research field. Lastly, our work on DAC feeds back into the reinforcement learning paradigm. Through the lens of DAC, we identify shortcomings in current state-of-the-art approaches and demonstrate how to solve these. In particular, intending to learn general policies for DAC, our work pushes the boundaries of generalization in reinforcement learning. We demonstrate how to efficiently incorporate domain knowledge when training general agents and propose to move from a reactive way of doing reinforcement learning to a proactive way by learning when to make new decisions
Abnormal thymocyte maturation in LynΔN transgenic mice.
No full text<p><b>A)</b> Representative thymi from 2-week old control and LynΔN mice. Bare scale : 0.5 cm. <b>B)</b> Total thymocyte numbers were determined. Lines indicate the mean, and each symbol represents one individual mouse. <b>C)</b> Total thymocytes from LynΔN and control mice were analyzed by flow cytometry for CD4 and CD8 expression, as shown in this representative flow cytometry profile. <b>D)</b> Proportion and <b>E)</b> number of all thymocyte subsets of 2-week old control and LynΔN mice were quantified; Lines indicate the mean, and each symbol represents one individual mouse<b>.</b> For these experiments, n = 15 for WT and n = 17 for LynΔN mice. P value, Student <i>t</i> test for unpaired data.</p
On-chip adiabatic demagnetisation refrigeration
No full textThis thesis describes the thermal modelling and simulation of on-chip adiabatic demagnetisation refrigeration. On-chip cooling is a novel refrigeration technique which has been developed to solve the apparent poor thermalisation of electrons in microkelvin nanoelectronics. Micrometre- and nanometre-scale electronics are fundamental to the development of quantum technologies and hot electrons often degrade the performance of these devices. Microkelvin electron temperatures, will allow for the investigation of new physical phenomena and exotic electronic states of matter. Prior to this work, microkelvin electron temperatures have been produced by a combination of on-chip and off-chip refrigeration. The combination of cooling elements obfuscates the importance and necessity of off-chip cooling components. Without a complete description of on-chip cooling thermal dynamics, this combination of techniques also complicated the optimisation of on-chip refrigeration. This thesis presents a first-principles thermal model and simulation of on-chip demagnetisation refrigeration. This work finds that the thermal dynamics of a coulomb blockade thermometer with on-chip cooling are well-captured by this model. Using the simulation, this work explores the limits, constraints and optimisation of on-chip cooling. The results of this exploration outline a path towards microkelvin electrons in a 10 mK refrigerator with on-chip demagnetisation cooling
The Minnesota Daily: April 17, 1912
No full textThis issue of the Minnesota Daily has been scanned from a microfilm copy of the original. It is representative of the physical copy it was scanned from, including duplicate pages, missing pages, or illegible pages. Paper copies of this issue of the Daily may also be held by the University of Minnesota Archives, and can be viewed by appointment.The Minnesota Daily. (1912). The Minnesota Daily: April 17, 1912. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/230869
Presence, Meaning, and Literary Criticism: An Interview with Hans Ulrich Gumbrecht
No full textEm entrevista realizada em agosto deste ano, Hans Ulrich Gumbrecht discutiu seu conceito de “produção de presença” na crítica literária, explorando a influência de Heidegger e as relações entre estética e política. Professor emérito da Universidade de Stanford e com forte ligação ao Brasil, ele compartilhou ideias de sua nova obra sobre temas como epifania e imaginação, mantendo seu estilo acessível e provocador, característico de sua trajetória intelectual.In an interview conducted in August this year, Hans Ulrich Gumbrecht discussed his concept of “production of presence” in literary criticism, exploring Heidegger’s influence and the connections between aesthetics and politics. An emeritus professor at Stanford University with strong ties to Brazil, he shared ideas from his new work on themes like epiphany and imagination, maintaining his accessible and provocative style, characteristic of his intellectual trajectory
INTEGRAL observation of the high-mass X-ray transient V 0332+53 during the 2005 outburst decline
No full textThe decline of the high mass X-ray transient V 0332+53 during the Dec. 2004 to Feb. 2005 outburst is analysed from the data recorded by INTEGRAL. The flux is shown to decrease exponentially until 2005 Feb. 10, with a decay time scale of ∼30 days above 20 keV and ∼20 days at lower energies, and to decrease linearly thereafter.
The energy spectrum is well modelled throughout the decay by a power law with a folding energy of ∼7.5 keV, and with two cyclotron absorption features. The folding energy does not vary significantly over the decay, but the spectrum becomes harder with time. Most importantly, we show that the parameters describing the fundamental cyclotron line around 27 keV do vary with time: its energy and depth increase (by about 17% for the energy in ∼6 weeks), while its width decreases. These changes of the cyclotron line parameters are interpreted as resulting from a change in the extent of the cyclotron scattering region.
Two quasi-periodic oscillations are also observed at various times during the observations, one at 0.05 Hz and another one near the pulsation frequency around 0.23 Hz
Don Juan Antonio Carrillo Salcedo
No full textAntigua Casa Central de Correos y Telégrafos. Universidad de Málaga (UMA)
Disputatio Theologica De Juramento In Symbola Et Libros Symbolicos
No full textKönigsberg, Univ., Theol. Disp., 1713Quam ... Praeses Christianus Sahmius, SS. Theol. D. & P. P. Diaconus Ecclesiæ Palæopolitanæ, & Respondens Fridericus Boltz, Reg. Pruss. S. Minist. Candid. In Auditorio Theologico. Anno MDCCXIII. d. Martii.Autopsie nach Ex. der ULB Sachsen-AnhaltVorlageform des Erscheinungsvermerks: Regiomonti, Typis Reusnerianis
