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71.
Chia-Hung Lin Jen-Shin Hong Martin Doerr 《International Journal on Digital Libraries》2008,8(2):115-132
Most information retrieval research focuses collecting documents that match the same set of concepts. This study considers
a more advanced problem, namely how to discover knowledge not contained in a single source from combined historical facts.
By using a well-designed core ontology in the cultural domain (CIDOC CRM, ISO21127), this study discusses the requirement
for a robust inference platform for real-life knowledge discovery and integration over distributed sources. The methodology
and design are justified in detail through functional requirements for an inference service with the capability of inferring
new knowledge from combinations of facts distributed over different sources. A number of critical issues for developing such
a robust inference platform are identified, namely (1) systematic accumulation of common concepts and inference rules; (2)
extending the ontology with metaclasses; (3) accumulation of factual and categorical knowledge; (4) incorporation of fuzzy
inference into the inference engine, and (5) improvement of performance and scalability in the inference engine. 相似文献
72.
We revisit the classic problem of spreading a piece of information in a group of \(n\) fully connected processors. By suitably adding a small dose of randomness to the protocol of Gasieniec and Pelc (Parallel Comput 22:903–912, 1996), we derive for the first time protocols that (i) use a linear number of messages, (ii) are correct even when an arbitrary number of adversarially chosen processors does not participate in the process, and (iii) with high probability have the asymptotically optimal runtime of \(O(\log n)\) when at least an arbitrarily small constant fraction of the processors are working. In addition, our protocols do not require that the system is synchronized nor that all processors are simultaneously woken up at time zero, they are fully based on push-operations, and they do not need an a priori estimate on the number of failed nodes. Our protocols thus overcome the typical disadvantages of the two known approaches, algorithms based on random gossip (typically needing a large number of messages due to their unorganized nature) and algorithms based on fair workload splitting (which are either not time-efficient or require intricate preprocessing steps plus synchronization). 相似文献
73.
Randomized search heuristics such as evolutionary algorithms, simulated annealing, and ant colony optimization are a broadly used class of general-purpose algorithms. Analyzing them via classical methods of theoretical computer science is a growing field. While several strong runtime analysis results have appeared in the last 20 years, a powerful complexity theory for such algorithms is yet to be developed. We enrich the existing notions of black-box complexity by the additional restriction that not the actual objective values, but only the relative quality of the previously evaluated solutions may be taken into account by the black-box algorithm. Many randomized search heuristics belong to this class of algorithms. We show that the new ranking-based model can give more realistic complexity estimates. The class of all binary-value functions has a black-box complexity of O(logn) in the previous black-box models, but has a ranking-based complexity of Θ(n). On the other hand, for the class of all OneMax functions, we present a ranking-based black-box algorithm that has a runtime of Θ(n/logn), which shows that the OneMax problem does not become harder with the additional ranking-basedness restriction. 相似文献
74.
I. S. Tereshina N. V. Kudrevatykh L. A. Ivanov G. A. Politova E. A. Tereshina D. Gorbunov M. Doerr K. Rogacki 《Journal of Materials Engineering and Performance》2017,26(10):4676-4680
A study is made of the effects of various factors such as time (7 years), temperature, high magnetic field up to 580 kOe and heat treatment (HT) on the morphological structure and magnetic hysteresis properties of a high-coercive nanocrystalline (Nd0.55Ho0.45)2.7(Fe0.8Co0.2)14B1.2 alloy with a low temperature coefficient of remanence. We find a rather weak time effect on (Nd0.55Ho0.45)2.7(Fe0.8Co0.2)14B1.2. After 7 years, the loss in the maximum magnetic energy product (BH)max is no more than 5%. Annealing of the sample at 250 °C for 30 min decreases the amount of amorphous phase from 7.2 to 1.7%, while the grains’ size of the 2-14-1 phase increases from 83 to 109 nm. For the HT alloy, a magnetization jump is observed at H ~500 kOe. It can be attributed to the first-order magnetization process or a spin-flip magnetic transition. Rectangularity of the hysteresis loop degrades after annealing. In case of the short-time heat treatment, losses in (BH)max are ~10%. 相似文献
75.
Sinsky J.H. Adamiecki A. Buhl L. Raybon G. Winzer P. Wohlgemuth O. Duelk M. Doerr C.R. Umbach A. Bach H.-G. Schmidt D. 《Lightwave Technology, Journal of》2008,26(1):114-120
A novel 107-Gbit/s optoelectronic receiver has been designed using hybrid integration of a photodiode and electronic demultiplexer. Using an ETDM transmitter, we achieve the lowest reported required OSNR for 107-Gbit/s CSRZ-OOK, 21 dB for 10-3 BER and a 231-1pattern length. Design methodology and performance data are presented. 相似文献
76.
Observation of WDM crosstalk in passive semiconductor waveguides 总被引:1,自引:0,他引:1
van Thourhout D. Doerr C.R. Joyner C.H. Pleumeekers J.L. 《Photonics Technology Letters, IEEE》2001,13(5):457-459
We show that passive InP-InGaAsP waveguides exhibit high nonlinear loss due to the highly energetic carriers generated by two-photon absorption. We have further demonstrated, for the first time, that due to this effect, severe crosstalk occurs between wavelength channels when they are transmitted through a semiconductor waveguide operated in the transparency region, at power levels used in typical wavelength-division-multiplexed (WDM) systems. Some solutions are proposed 相似文献
77.
Sandoval Kate; McDaniel Kathrine M.; Murawski Nathen J.; Doerr Celeste E.; Calton Jeffrey L. 《Canadian Metallurgical Quarterly》2008,122(6):1226
Head direction (HD) cells have been speculated to be part of a network mediating navigational behavior. Previous work has shown that combined administration of serotonergic and muscarinic antagonists eliminates hippocampal theta activity and produces navigational deficits more severe than blockade of either neurotransmitter system alone. The authors sought to assess this effect on the directional characteristics of HD cells. HD cells were recorded from the anterior dorsal thalamus of Long-Evans rats before and after administration of the serotonergic antagonist methiothepin, the muscarinic antagonist scopolamine, both drugs, or saline. Combined drug administration produced HD cells with preferred directions that drifted within recording sessions. In addition, cells showed shifts in the preferred directions at the start of a session relative to the position of the major landmarks, suggesting that combined drug administration led to deficits in landmark control of the HD system. Single drug exposures to methiothepin or scopolamine did not noticeably affect the directional characteristics of HD cells. This finding that navigation-impairing drugs can disrupt the HD signal provides further evidence that this network plays an important role in navigational behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
78.
Doerr C.R. Kim H.K. Stulz L.W. Cappuzzo M. Gomez L. Paunescu A. Laskowski E. Boivin L. Shunk S. 《Photonics Technology Letters, IEEE》2001,13(7):690-692
This letter presents an integrated multi/demultiplexer that can dynamically and independently control the curvature, tilt, and attenuation of its passband shapes, in order to reduce the signal distortion caused by other filters in the network. 40 Gb/s performance is demonstrated 相似文献
79.
Catherine J. Andersen Lydia Dupree Kristina Murray Nicholas Ragonesi Kaley McMullen Layra Cintrón-Rivera Adam Doerr 《Lipids》2020,55(6):615-626
Cellular lipid metabolism, lipoprotein interactions, and liver X receptor (LXR) activation have been implicated in the pathophysiology and treatment of cancer, although findings vary across cancer models and by lipoprotein profiles. In this study, we investigated the effects of human-derived low-density lipoproteins (LDL), high-density lipoproteins (HDL), and HDL-associated proteins apolipoprotein A1 (apoA1) and serum amyloid A (SAA) on markers of viability, cholesterol flux, and differentiation in K562 cells—a bone marrow-derived, stem-like erythroleukemia cell model of chronic myelogenous leukemia (CML). We further evaluated whether lipoprotein-mediated effects were altered by concomitant LXR activation. We observed that LDL promoted higher K562 cell viability in a dose- and time-dependent manner and increased cellular cholesterol concentrations, while LXR activation by the agonist TO901317 ablated these effects. LXR activation in the presence of HDL, apoA1 and SAA-rich HDL suppressed K562 cell viability, while robustly inducing mRNA expression of ATP-binding cassette transporter A1 (ABCA1). HDL and its associated proteins additionally suppressed mRNA expression of anti-apoptotic B-cell lymphoma-extra large (BCL-xL), and the erythroid lineage marker 5′-aminolevulinate synthase 2 (ALAS2), while SAA-rich HDL induced mRNA expression of the megakaryocytic lineage marker integrin subunit alpha 2b (ITGA2B). Together, these findings suggest that lipoproteins and LXR may impact the viability and characteristics of CML cells. 相似文献
80.
C.R. Doerr M. Cappuzzo E. Chen A. Wong-Foy L. Gomez A. Griffin L. Buhl 《Photonics Technology Letters, IEEE》2005,17(6):1211-1213
We present a planar lightwave circuit curved 2/spl times/2 coupler. Its splitting ratio has a low sensitivity to wavelength, polarization, and fabrication yet is low-loss and compact. We present simple formulae for its design. We demonstrate a 50/50 version in silica-on-silicon waveguides. We discuss the tradeoff between amplitude accuracy and phase accuracy in such densensitized couplers. 相似文献