13,584 research outputs found
Controlled continuous --Frames in Hilbert -Modules
No full textThe frame theory is dynamic and exciting with various pure and applied
mathematics applications. In this paper, we introduce and study the concept of
Controlled Continuous --Frames in Hilbert -Modules, which is
a generalization of discrete controlled --Frames in Hilbert
-Modules. Also, we give some properties
Ant Colony Optimization for Control
No full textThe very basis of this thesis is the collective behavior of ants in colonies. Ants are an excellent example of how rather simple behavior on a local level can lead to complex behavior on a global level that is beneficial for the individuals. The key in the self-organization of ants is communication through pheromones. When an ant forages for food, it is biased to search along trails of stronger pheromone concentrations. The moment it finds food, it will walk back to the nest while depositing pheromones and thereby contributing to the reinforcement of a successful trail. Inspired by this mechanism, research within an engineering context has led to the development of the field of Ant Colony Optimization (ACO). Specifically developed for efficiently solving combinatorial optimization problems, ACO has been successfully applied to routing in road traffic and Internet networks. In this thesis, we take the principles behind ACO to the domain of control policy learning. A control policy is a mapping from states to actions and our objective is to develop methods to learn the optimal control policy for a given dynamic system by interacting with it. We call our methods Ant Colony Learning (ACL) and their power lies in the fact that there is a set of ants, from which each ant interacts with the system and influences the other ants through updating pheromone levels associated with the visited state-action pairs. In experiments involving control problems that have a discrete state space and deterministic state transitions, it turns out that ACL converges quickly to the optimal solution. We also observe that increasing the number of ants in the algorithm results in a decrease of the number of trials required for convergence to the optimal policy. An analytical study of the convergence behavior of ACL reveals that for systems with discrete and noiseless state transitions, the expected policy converges to the optimal policy in the case of using only one ant. Another major part of this thesis deals with the application of ACL to control problems with continuous state spaces. In order to capture a continuous space with a finite number of elements, we study two ways of partitioning the state space and their incorporation in the ACL framework. In crisp ACL, the state space is partitioned using bins. Each state measurement is assigned to exactly one bin, which leads to the introduction of discretization noise, rendering an originally deterministic system non-deterministic and restricting the performance of the algorithm. We find that a better way of partitioning the state space is by using fuzzy triangular membership functions. The continuous state measurement then belongs to multiple membership functions to a certain degree. With fuzzy partitioning, the continuity of the state variables is preserved and no non-determinism is introduced. We call this method fuzzy ACL. The developed generalized ACL algorithm unifies both crisp and fuzzy ACL. The behavior and performance of crisp and fuzzy ACL are further studied using simulation experiments. We study the influence of the local and global pheromone decay rates, the number of ants, and the density of the state space partitioning grid on the learning performance. Especially, the performance of crisp ACL improves for a small local pheromone decay rate, while fuzzy ACL outperforms crisp ACL over the whole line. In general, crisp ACL is much more sensitive to the choice of the pheromone decay parameters than fuzzy ACL. We find that using more ants leads to faster convergence, but that the number of ants does not need to be extremely large to obtain a satisfactory performance. With regard to the scaling of ACL, crisp ACL reveals a slow, but gradual improvement of the learning for an increasing state space partitioning density. Fuzzy ACL, on the other hand, improves more rapidly and requires fewer ants to learn a better control policy. Finally, we present a general modeling framework for swarms of moving agents. It turns out that ACL fits within this framework and as such can be unified with other swarm intelligence techniques. In the future, this could result in beneficial integration of elements from other swarm intelligence techniques into ACL, or the other way around.Delft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
Tensor product for g-fusion frame in hilbert modules
No full textIn this paper, we stady the tensor product of fusion frame in Hilbert modules and we give the frame operator for a pair of fusion bessel sequences in tensor product of Hilbert modules
Randomized placebo-controlled EPPIC trials of AST-120 in CKD
No full textReduced GFR in patients with CKD causes systemic accumulation of uremic toxins, which has been correlated with disease progression and increased morbidity. The orally administered spherical carbon adsorbent AST-120 reduces systemic toxin absorption through gastrointestinal sequestration, which may slow disease progression in these patients. The multinational, randomized, double-blind, placebocontrolled Evaluating Prevention of Progression in CKD (EPPIC)-1 and EPPIC-2 trials evaluated the effects of AST-120 on the progression of CKD when added to standard therapy. We randomly assigned 2035 adults with moderate to severe disease (serum creatinine at screening, 2.0-5.0 mg/dl for men and 1.5- 5.0mg/dl for women) to receive either placebo or AST-120 (9 g/d). The primary end point was a composite of dialysis initiation, kidney transplantation, and serum creatinine doubling. Each trial continued until accrual of 291 primary end points. The time to primary end point was similar between the AST-120 and the placebo groups in both trials (EPPIC-1: hazard ratio, 1.03; 95% confidence interval, 0.84 to 1.27; P=0.78) (EPPIC-2: hazard ratio, 0.91; 95% confidence interval, 0.74 to 1.12; P=0.37); a pooled analysis of both trials showed similar results. The estimated median time to primary end points for the placebo groups was 124 weeks for power calculations, but actual times were 189.0 and 170.3 weeks for EPPIC-1 and EPPIC-2, respectively. Thus, disease progression was more gradual than expected in the trial populations. In conclusion, the benefit of adding AST-120 to standard therapy in patients with moderate to severe CKD is not supported by these data
PSYNDEX Tests Review für AST 3/A - ALLGEMEINER SCHULLEISTUNGSTEST FÜR DIE 3. SCHULSTUFE - ÖSTERREICHISCHE VERSION
No full textThis is a PSYNDEX Tests Review of AST 3/A - ALLGEMEINER SCHULLEISTUNGSTEST FÜR DIE 3. SCHULSTUFE - ÖSTERREICHISCHE VERSION. PSYNDEX Tests Reviews are written in German and describe and evaluate psychological and educational tests used in the German-speaking countries. PSYNDEX Tests is offered by the Leibniz Institute for Psychology as open access documentation.Das ist ein PSYNDEX Tests Review zu AST 3/A - ALLGEMEINER SCHULLEISTUNGSTEST FÜR DIE 3. SCHULSTUFE - ÖSTERREICHISCHE VERSION. PSYNDEX Tests Reviews beschreiben und bewerten zentrale psychologische und pädagogische Testverfahren, die in den deutschsprachigen Ländern eingesetzt werden, nach einem standardisierten Raster. PSYNDEX Tests wird durch das Leibniz-Institut für Psychologie als Open Access Dokumentation angeboten.publishedVersio
TWO-PHOTON SPECTROSCOPY OF THE AND STATES OF
No full text Research supported by AFOSR K. Hoshiba et al. J. Phys. B 18, 1.875 (1985). T. Sakai et al., J. Phys. B. 21, 229 (1988).Author Institution: Molecular Physics Laboratory, SRI InternationalThe and states of are excited from the ground by two photons near 207 nm and detected by vuv fluorescence or by ionization by a third photon. The laser source for these measurements is an excimer-pumped dye laser operating with PBBO dye at 415 nm. This light is doubled in a crystal and focused into a cell containing a mixture of in He. The uv wavelengths were calibrated against the (3.0) band in NO, which was calibrated against in the visible. Vibrational levels were observed in the state and in the state, based on the previous electron-impact , and partially resolved rotationally (the effective excitation linewidth is ). These assignments are supported by simulations of the two-photon excitation spectra. Although the fluorescence has not yet been spectrally resolved, we believe that it arises predominantly from the triplet state even when the singlet is initially excited. In the latter case, the fluorescence is temporally delayed, and increases in intensity as the He density is increased. The two-phonon excitation scheme we have developed should be useful in investigating the kinetics of the 158 nm laser, which is believed to arise from a transition from the outer well of the state to a weakly bound state correlating to ground state atoms.$^{2}
Some remarks on the equality
No full textsummary:We show that the equality is a necessary condition for the validity of certain results about isomorphic properties in the projective tensor product of two Banach spaces under some approximation property type assumptions
-closed sets and a new separation axiom in Alexandroff spaces
No full textsummary:In this paper we introduce the concept of -closed sets and investigate some of its properties in the spaces considered by A. D. Alexandroff [1] where only countable unions of open sets are required to be open. We also introduce a new separation axiom called -axiom in the Alexandroff spaces with the help of -closed sets and investigate some of its consequences
A note on ideal C-completions and amenability
No full textFor a discrete group , we consider certain ideals of sequences with prescribed rate of convergence to zero. We show that
the equality between the full group C-algebra of and the
C-completion in the sense of Brown
and Guentner implies that is amenable
On the real rank of -algebras of nilpotent locally compact groups
No full textIf is an almost connected, nilpotent, locally compact group then the real rank of the -algebra is given by , where is the connected component of the identity element. In particular, for the continuous Heisenberg group ,
- …
