| 1. |
- Lawoko, Martin, et al.
(author)
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Changes in the lignincarbohydrate complex in softwood kraft pulp during kraft and oxygen delignification
- 2004
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In: Holzforschung. - 0018-3830 .- 1437-434X. ; 58:6, s. 603-610
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Journal article (peer-reviewed)abstract
- Three kraft pulps in the kappa number range between 50 and 20 and the same pulps oxygendelignified to similar lignin contents (kappa approximately 6) were analyzed for lignincarbohydrate complexes (LCC) by a method based on selective enzymatic hydrolysis of the cellulose, and quantitative fractionation of the LCC. Between 85 and 90% of residual lignin in the unbleached kraft pulp and all residual lignin in the oxygendelignified pulps were isolated as LCC. Three types of complexes were found; viz., xylanlignin, glucomannanligninxylan and glucanlignin complexes. After pulping to a high kappa number, most of the residual lignin was linked to xylan. Different delignification rates were observed so that most of the residual lignin was linked to glucomannan when the pulping was extended to a low kappa number. With increasing degree of oxygen delignification, a similar trend in the delignification rates of LCC was observed so that the residual lignin was increasingly linked to glucomannan. Complex LCC network structures seemed to be degraded into simpler structures during delignification. The differences in delignification rates are discussed with reference to the solubility properties and structural differences of LCC, and to morphological aspects of the pulp.
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| 2. |
- Antonio Ribeiro, Luiz, et al.
(author)
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Polaron stability in molecular semiconductors: theoretical insight into the impact of the temperature, electric field and the system dimensionality
- 2015
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In: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 17:14, s. 8973-8982
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Journal article (peer-reviewed)abstract
- A semi-empirical Holstein-Peierls model is used to study the temperature effects on the polaron stability in organic semiconductors at a molecular scale. The approach takes into account both intra- and intermolecular electron-lattice interactions and is aimed at describing charge transport in the system. Particularly, we present a systematic numerical investigation to characterize the influence of both temperature and electric field on the stability as well as mobility of the polaron. It is found that the parameter space for which the polaron is dynamically stable is quite limited and the variations in some of these parameters strongly depend on the temperature. The electric field can play a role in further localizing the charge causing a compression of the lattice distortions associated with the polaron, increasing thereby its stability, up to a field strength of approximately 2.0 mV angstrom(-1). Considering field strengths higher than this critical value, the polaron is annihilated spreading charge through the lattice. Furthermore, we have studied the polaron mobility as a function of the anisotropy of the system, going from a one-dimensional system via a highly anisotropic two-dimensional system to a uniform two-dimensional system. There is a clearly observed mobility edge for the polaron; it exhibits a high mobility in the one-dimensional system but as the coupling in the second dimension is turned on the polaron slows down and becomes immobile in the uniform system. The results provided by this transport mechanism are in good agreement with experimental observations and may provide guidance to improve the charge transport in organic optoelectronic devices.
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| 3. |
- Ding, Xinghao, et al.
(author)
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High-resolution source localization exploiting the sparsity of the beamforming map
- 2022
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In: Signal Processing. - : Elsevier BV. - 0165-1684. ; 192
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Journal article (peer-reviewed)abstract
- Beamforming technology plays a significant role in source localization and quantification. As traditional delay-and-sum beamformers generally yield low spatial resolution, as well as suffer from the occurrence of spurious sources, different forms of deconvolution methods have been proposed in the literature. In this work, we propose two approaches based on a sparse reconstruction framework combined with the use of the Fourier-based efficient implementation techniques. Numerical simulations and experimental data analysis show the effectiveness and advantages of the proposed methods.
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| 4. |
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| 5. |
- Osman, M.H., et al.
(author)
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An analysis of machine learning algorithms for condensing reverse engineered class diagrams
- 2013
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In: IEEE International Conference on Software Maintenance, ICSM. - : IEEE. - 1063-6773.
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Conference paper (peer-reviewed)abstract
- There is a range of techniques available to reverse engineer software designs from source code. However, these approaches generate highly detailed representations. The condensing of reverse engineered representations into more high-level design information would enhance the understandability of reverse engineered diagrams. This paper describes an automated approach for condensing reverse engineered diagrams into diagrams that look as if they are constructed as forward designed UML models. To this end, we propose a machine learning approach. The training set of this approach consists of a set of forward designed UML class diagrams and reverse engineered class diagrams (for the same system). Based on this training set, the method 'learns' to select the key classes for inclusion in the class diagrams. In this paper, we study a set of nine classification algorithms from the machine learning community and evaluate which algorithms perform best for predicting the key classes in a class diagram. © 2013 IEEE.
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| 6. |
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| 7. |
- Antonioli, Roberto Pinto, et al.
(author)
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Decentralized User Scheduling for Rate-Constrained Sum-Utility Maximization in the MIMO IBC
- 2020
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In: IEEE Transactions on Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 0090-6778 .- 1558-0857. ; 68:10, s. 6215-6229
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Journal article (peer-reviewed)abstract
- While the problems of sum-rate maximization and sum-power minimization subject to quality of service (QoS) constraints in the multiple input multiple output interference broadcast channel (MIMO IBC) have been widely studied, most of the proposed solutions have neglected the user scheduling aspect assuming that a feasible set of users has been previously selected. However, ensuring QoS for each user in the MIMO IBC involves the joint optimization of transmit/receive beamforming vectors, transmit powers, and user scheduling variables. To address the full problem, we propose a novel formulation of a rate-constrained sum-utility maximization problem which allows to either deactivate users or minimize the QoS degradation for some scheduled users in infeasible scenarios. Remarkably, this is achieved avoiding the complexity of traditional combinatorial formulations, but rather by introducing a novel expression of the QoS constraints that allows to solve the problem in a continuous domain. We propose centralized and decentralized solutions, where the decentralized solutions focus on practical design and low signaling overhead. The proposed solutions are then compared with benchmarking algorithms, where we show the effectiveness of the joint scheduling and transceiver design as well as the flexibility of the proposed solution performing advantageously in several MIMO IBC scenarios.
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| 9. |
- Gatz, Sebastian
(author)
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Xeno_Monads of Control Architectures
- 2024
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In: Book of Abstracts. ; , s. 11-11
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Conference paper (peer-reviewed)abstract
- The “xeno” – “the other” – is a prefix found in such hyphenated bridge words such as xeno-poetics, xeno-politics, xeno-feminism, or xeno-architecture. Xeno is the other, the not-self. But who or wha tis this not-self and where is it? In contemporary architectural discourse we find an increasing interest in more-than-human justice, speculation, or realization: ontological or critical posthumanisms and new materialisms explore nonhuman agency and transhumanist or cybernetic posthumanists celebrate the (always coming) fusion of the technological other with the self in order to overcome nature’s imposed (mortal) limits. There seems to be two types of nonhumans, related to the different – and often opposing – understandings of posthumanism: the man-made nonhuman and the non-man-made nonhuman. The xeno seems to mingle with ideologies of the former. A monad – as found in different monadologies, such as Leibnitz’s or the theosophical – is the smallest part of a metaphysical entity. It is the invisible sibling of the, almost outdated and refuted, physical atom. The monad seems to be exclusively found in life, in the non-man-made. In my presentation I would like to speculate on the xeno_monad, a conceptual overlap of the man-made and non-man-made entity and where it is physically and metaphysically situated in architecture. Physically, we might find such speculative entity in either the weathering processes of ruination and decay (non-man-made) or in the digital infrastructures which make up an increasing part of our architectural matters (man-made). Metaphysically, we find it in human perception (does the nonhuman even exist without human perception?): it is found in the fear of losing control over(architectural) matters and (information) flows; it is found in the desire to project human shortcomings onto the other, the outside rather than the inside; and it is found in the spiritual, sometimes perversely mixed with the transhuman, desire to overcome human limitations.
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