612 research outputs found
Efficient Generation of Model Bulk Heterojunction Morphologies for Organic Photovoltaic Device Modeling
Kinetic Monte Carlo (KMC) simulations have been previously used to model and
understand a wide range of behaviors in bulk heterojunction (BHJ) organic
photovoltaic devices, from fundamental mechanisms to full device performance.
One particularly unique and valuable aspect of this type of modeling technique
is the ability to explicitly implement models for the bicontinuous
nanostructured morphology present in these devices. For this purpose, an
Ising-based method for creating model BHJ morphologies has become prevalent.
However, this technique can be computationally expensive, and a detailed
characterization of this method has not yet been published. Here, we perform a
thorough characterization of this method and describe how to efficiently
generate controlled model BHJ morphologies. We show how the interaction energy
affects the tortuosity of the interconnected domains and the resulting charge
transport behavior in KMC simulations. We also demonstrate how to dramatically
reduce calculation time by several orders of magnitude without detrimentally
affecting the resulting morphologies. In the end, we propose standard
conditions for generating model morphologies and introduce a new open-source
software tool. These developments to the Ising method provide a strong
foundation for future simulation and modeling of BHJ organic photovoltaic
devices that will lead to a more detailed understanding of the important link
between morphological features and device performance.Comment: Main article: 9 pages, 6 figures, Supplementary Information: 6 pages,
6 figure
Normal Numbers and the Borel Hierarchy
We show that the set of absolutely normal numbers is -complete in the Borel hierarchy of subsets of real numbers. Similarly,
the set of absolutely normal numbers is -complete in the effective
Borel hierarchy
A computable absolutely normal Liouville number
We give an algorithm that computes an absolutely normal Liouville number.Fil: Becher, Veronica Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Heiber, Pablo Ariel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Slaman, Theodore A.. University of California at Berkeley; Estados Unido
U.S.-Korea economic relations
노트 : A publication of the Korea Economic Institute and the Korea Institute for International Economic Polic
Normal numbers and finite automata
We give an elementary and direct proof of the following theorem: A real number is normal to a given integer base if, and only if, its expansion in that base is incompressible by lossless finite-state compressors (these are finite automata augmented with an output transition function such that the automata input–output behaviour is injective; they are also known as injective finite-state transducers). As a corollary we obtain V.N. Agafonov’s theorem on the preservation of normality on subsequences selected by finite automata.Fil: Becher, Veronica Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Heiber, Pablo Ariel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
A linearly computable measure of string complexity
AbstractWe present a measure of string complexity, called I-complexity, computable in linear time and space. It counts the number of different substrings in a given string. The least complex strings are the runs of a single symbol, the most complex are the de Bruijn strings. Although the I-complexity of a string is not the length of any minimal description of the string, it satisfies many basic properties of classical description complexity. In particular, the number of strings with I-complexity up to a given value is bounded, and most strings of each length have high I-complexity
- …