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21.
Burkhard H. Freyer P. Stephan Heyns Nico J. Theron 《Journal of Intelligent Manufacturing》2014,25(3):473-487
Signal processing using orthogonal cutting force components for tool condition monitoring has established itself in literature. In the application of single axis strain sensors however a linear combination of cutting force components has to be processed in order to monitor tool wear. This situation may arise when a single axis piezoelectric actuator is simultaneously used as an actuator and a sensor, e.g. its vibration control feedback signal exploited for monitoring purposes. The current paper therefore compares processing of a linear combination of cutting force components to the reference case of processing orthogonal components. Reconstruction of the dynamic force acting at the tool tip from signals obtained during measurements using a strain gauge instrumented tool holder in a turning process is described. An application of this dynamic force signal was simulated on a filter-model of that tool holder that would carry a self-sensing actuator. For comparison of the orthogonal and unidirectional force component tool wear monitoring strategies the same time-delay neural network structure has been applied. Wear-sensitive features are determined by wavelet packet analysis to provide information for tool wear estimation. The probability of a difference less than 5 percentage points between the flank wear estimation errors of above mentioned two processing strategies is at least 95 %. This suggests the viability of simultaneous monitoring and control by using a self-sensing actuator. 相似文献
22.
John Case Sanjay Jain Yuh Shin Ong Pavel Semukhin Frank Stephan 《Journal of Computer and System Sciences》2014
Automatic classes are classes of languages for which a finite automaton can decide whether a given element is in a set given by its index. The present work studies the learnability of automatic families by automatic learners which, in each round, output a hypothesis and update a long-term memory, depending on the input datum, via an automatic function. Many variants of automatic learners are investigated: where the long-term memory is restricted to be the current hypothesis whenever this exists, cannot be of length larger than the length of the longest datum seen, or has to consist of a constant number of examples seen so far. Learnability is also studied with respect to queries which reveal information about past data or past computation history; the number of queries per round is bounded by a constant. 相似文献
23.
Martin Atzmueller Martin Becker Mark Kibanov Christoph Scholz Stephan Doerfel Andreas Hotho 《New Review of Hypermedia and Multimedia》2014,20(1):53-77
The combination of ubiquitous and social computing is an emerging research area which integrates different but complementary methods, techniques, and tools. In this paper, we focus on the Ubicon platform, its applications, and a large spectrum of analysis results. Ubicon provides an extensible framework for building and hosting applications targeting both ubiquitous and social environments. We summarize the architecture and exemplify its implementation using four real-world applications built on top of Ubicon. In addition, we discuss several scientific experiments in the context of these applications in order to give a better picture of the potential of the framework, and discuss analysis results using several real-world data sets collected utilizing Ubicon. 相似文献
24.
Hagen V Frings S Wiesner B Helm S Kaupp UB Bendig J 《Chembiochem : a European journal of chemical biology》2003,4(5):434-442
[7-(Dimethylamino)coumarin-4-yl]methyl (DMACM) and [7-(diethylamino)coumarin-4-yl]methyl (DEACM) esters of 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) and 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) are described as novel caged compounds for 8-bromo-substituted cyclic nucleotides. Synthesis is accomplished by treatment of the free acids of the cyclic nucleotides with the corresponding 7(dialkylamino)-substituted 4(diazomethyl)coumarins. Irradiation of the DMACM- and DEACM-caged cyclic nucleotides with UV light stimulates the release of the cyclic nucleotides within roughly a nanosecond. The new caged compounds are resistant to hydrolysis in aqueous buffers and exhibit long-wavelength absorption properties with maxima at 400 nm, high extinction coefficients, and high quantum yields (0.15-0.31). Their favorable properties render these compounds the most efficient and rapid phototriggers of 8-bromo-substituted cyclic nucleotides known. The usefulness of the compounds for physiological studies under nondamaging light conditions was examined in HEK293 cells expressing the alpha subunit of the cyclic-nucleotide-gated (CNG) channel of cone photoreceptors (CNGA3) and of olfactory neurons (CNGA2) by using confocal laser scanning microscopy and the patch clamp technique. 相似文献
25.
26.
The correctness of model transformations is a crucial element for model-driven engineering of high-quality software. A prerequisite to verify model transformations at the level of the model transformation specification is that an unambiguous formal semantics exists and that the implementation of the model transformation language adheres to this semantics. However, for existing relational model transformation approaches, it is usually not really clear under which constraints particular implementations really conform to the formal semantics. In this paper, we will bridge this gap for the formal semantics of triple graph grammars (TGG) and an existing efficient implementation. While the formal semantics assumes backtracking and ignores non-determinism, practical implementations do not support backtracking, require rule sets that ensure determinism, and include further optimizations. Therefore, we capture how the considered TGG implementation realizes the transformation by means of operational rules, define required criteria, and show conformance to the formal semantics if these criteria are fulfilled. We further outline how static and runtime checks can be employed to guarantee these criteria. 相似文献
27.
In the current study, the development of the silicate structure of synthetic calcium silicate hydrates with different calcium contents was followed by in-situ infrared (IR) spectroscopy and correlated to the in-situ phase development evaluated by X-ray diffraction (XRD). A baseline correction method initially developed for X-ray diffractograms was successfully adapted for the complex background of the fingerprint region in in-situ IR, which significantly contributed to signal quality and reproducibility. The development of separate silicate infrared bands could be monitored over 24 h of reaction. These bands could be assigned to oligomeric and dimeric species based on their time and stoichiometry-dependent development. It was clearly shown that the main peak of the dimeric silicate species was overlooked in the literature. The correlation of time-dependent events to in-situ XRD revealed that changes in the unit cell of calcium silicate hydrate are related to silicate polymerization. The results were compared to 29Si-MAS-NMR, which highlighted the benefits of in-situ IR spectroscopy. 相似文献
28.
Nirvana Delgado Otalvaro Pembe Gül Bilir Karla Herrera Delgado Stephan Pitter Jörg Sauer 《化学,工程师,技术》2021,93(5):754-761
Artificial neural networks (ANNs) are designed and implemented to model the direct synthesis of dimethyl ether (DME) from syngas over a commercial catalyst system. The predictive power of the ANNs is assessed by comparison with the predictions of a lumped model parameterized to fit the same data used for ANN training. The ANN training converges much faster than the parameter estimation of the lumped model, and the predictions show a higher degree of accuracy under all conditions. Furthermore, the simulations show that the ANN predictions are also accurate even at some conditions beyond the validity range. 相似文献
29.
Eduardo Fischer Kerche Vinícius Demétrio da Silva Gabriela da Silveira Jankee Henri Stephan Schrekker Rafael de Avila Delucis Siva Irulappasamy Sandro Campos Amico 《应用聚合物科学杂志》2021,138(21):50492
This article reports an aramid pulp (AP) treated with two ionic liquids (IL), namely 1-n-butyl-3-methylimidazolium chloride (C4.Cl) and 1-carboxymethyl-3-methylimidazolium chloride (HO2C), and its use as a filler in reinforced rigid polyurethane foams (RPUF). The RPUF were incorporated with the treated AP at three weight fractions (c.a. 0.1, 0.5, and 1.0 wt%) and were produced by the free rising method. The results showed that the studied IL promoted a better interaction between the AP and the RPUF system, which increased the overall reactivity, imparting a higher cell anisotropy. This also yielded a positive effect in mechanical properties and thermal stability of the RPUF. Compared to the neat RPUF, outstanding increases of approximately 50 and 20% were achieved in compressive modulus and strength, respectively. In all, the use of IL promoted increased compatibility between matrix and reinforcement, especially that HO2C IL. 相似文献
30.
Tröger Armin Svensson Glenn P. Galbrecht Hans-Martin Twele Robert Patt Joseph M. Bartram Stefan Zarbin Paulo H. G. Segraves Kari A. Althoff David M. von Reuss Stephan Raguso Robert A. Francke Wittko 《Journal of chemical ecology》2021,47(12):1025-1041
Journal of Chemical Ecology - The obligate pollination mutualism between Yucca and yucca moths is a classical example of coevolution. Oviposition and active pollination by female yucca moths occur... 相似文献