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51.
Evolutionary rule-based systems for imbalanced data sets 总被引:2,自引:1,他引:1
Albert Orriols-Puig Ester Bernadó-Mansilla 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(3):213-225
This paper investigates the capabilities of evolutionary on-line rule-based systems, also called learning classifier systems
(LCSs), for extracting knowledge from imbalanced data. While some learners may suffer from class imbalances and instances
sparsely distributed around the feature space, we show that LCSs are flexible methods that can be adapted to detect such cases
and find suitable models. Results on artificial data sets specifically designed for testing the capabilities of LCSs in imbalanced
data show that LCSs are able to extract knowledge from highly imbalanced domains. When LCSs are used with real-world problems,
they demonstrate to be one of the most robust methods compared with instance-based learners, decision trees, and support vector
machines. Moreover, all the learners benefit from re-sampling techniques. Although there is not a re-sampling technique that
performs best in all data sets and for all learners, those based in over-sampling seem to perform better on average. The paper
adapts and analyzes LCSs for challenging imbalanced data sets and establishes the bases for further studying the combination
of re-sampling technique and learner best suited to a specific kind of problem. 相似文献
52.
53.
The partial replacement of sodium chloride by other chloride salts has been proposed as a possible strategy to reduce the sodium content of cured meat products. 相似文献
54.
The objective of this work was to determine the effects of extrusion cooking on the stability of ochratoxin A (OTA) in an artificially contaminated hulled barley meal (0.73-mm grain diameter) using a single screw extruder. The extrusion cooking parameters were temperature (140, 160, and 180 degrees C), initial moisture content of barley meal (24, 27 and 30%), and residence time (30, 40, 50, 60, and 70 s). Both unextruded and extruded samples were analyzed for OTA by high-performance liquid chromatography. Extrusion cooking variables significantly affected the stability of OTA (P < 0.05). Greater OTA reductions were achieved at higher residence time (70 s), medium temperature level (160 degrees C), and either high (30%) or low moisture (24%) content of samples. The amount of OTA destroyed during the extrusion process ranged from 17 to 86% depending on the studied parameters. The decrease in the amount of OTA after extrusion cooking followed first-order kinetics, showing that the fastest treatment in OTA reduction was that at 140 degrees C and 24% of moisture content. 相似文献
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57.
The Shortening of MWNT‐SPION Hybrids by Steam Treatment Improves Their Magnetic Resonance Imaging Properties In Vitro and In Vivo
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Laura Cabana Maxime Bourgognon Julie T.‐W. Wang Andrea Protti Rebecca Klippstein Rafael T. M. de Rosales Ajay M. Shah Josep Fontcuberta Ester Tobías‐Rossell Jane K. Sosabowski Khuloud T. Al‐Jamal Gerard Tobias 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(21):2893-2905
Carbon nanotubes (CNTs) have been advocated as promising nanocarriers in the biomedical field. Their high surface area and needle‐like shape make these systems especially attractive for diagnostic and therapeutic applications. Biocompatibility, cell internalization, biodistribution, and pharmacokinetic profile have all been reported to be length dependent. In this study, further insights are gotten on the role that the length of CNTs plays when developing novel contrast agents for magnetic resonance imaging (MRI). Two samples of CNTs with different length distribution have been decorated with radio‐labeled iron oxide nanoparticles. Despite characterization of the prepared hybrids reveals a similar degree of loading and size of the nanoparticles for both samples, the use of short CNTs is found to enhance the MRI properties of the developed contrast agents both in vitro and in vivo compared to their long counterparts. 相似文献
58.
In this paper we describe a comparison of two analytical methods for educational computer games for young children. The methods
compared in the study are the Structured Expert Evaluation Method (SEEM) and the Combined Heuristic Evaluation (HE) (based
on a combination of Nielsen’s HE and the fun-related concepts from Malone and Lepper) with both usability and fun heuristics
for children’s computer games. To verify SEEM’s relative quality, a study was set up in which adult evaluators predicted problems
in computer games. Outcomes based on thoroughness (whether the analytical method finds all problems), validity (whether the
analytical method uncovers problems that are likely to be true) and appropriateness (whether the method is applied correctly)
are compared. The results show that both the thoroughness and validity of SEEM are higher than the thoroughness and validity
of the Combined HE. The appropriateness scores indicate that SEEM gives evaluators more guidance when predicting problems
than the Combined HE does.
相似文献
Wolmet BarendregtEmail: |
59.
Mario Prats Ester Martínez Pedro J. Sanz Angel P. del Pobil 《Intelligent Service Robotics》2008,1(4):321-335
This paper describes the UJI librarian robot, a mobile manipulator that is able to autonomously locate a book in an ordinary
library, and grasp it from a bookshelf, by using eye-in-hand stereo vision and force sensing. The robot is only provided with
the book code, a library map and some knowledge about its logical structure and takes advantage of the spatio-temporal constraints
and regularities of the environment by applying disparate techniques such as stereo vision, visual tracking, probabilistic
matching, motion estimation, multisensor-based grasping, visual servoing and hybrid control, in such a way that it exhibits
a robust and dependable performance. The system has been tested, and experimental results show how it is able to robustly
locate and grasp a book in a reasonable time without human intervention. 相似文献
60.
Irene Rodríguez Ester Saavedra Henoc del Rosario Juan Perdomo Jos Quintana Filippo Prencipe Paola Oliva Romeo Romagnoli Francisco Estvez 《International journal of molecular sciences》2021,22(24)
The World Health Organization reported that approximately 324,000 new cases of melanoma skin cancer were diagnosed worldwide in 2020. The incidence of melanoma has been increasing over the past decades. Targeting apoptotic pathways is a potential therapeutic strategy in the transition to preclinical models and clinical trials. Some naturally occurring products and synthetic derivatives are apoptosis inducers and may represent a realistic option in the fight against the disease. Thus, chalcones have received considerable attention due to their potential cytotoxicity against cancer cells. We have previously reported a chalcone containing an indole and a pyridine heterocyclic rings and an α-bromoacryloylamido radical which displays potent antiproliferative activity against several tumor cell lines. In this study, we report that this chalcone is a potent apoptotic inducer for human melanoma cell lines SK-MEL-1 and MEL-HO. Cell death was associated with mitochondrial cytochrome c release and poly(ADP-ribose) polymerase cleavage and was prevented by a non-specific caspase inhibitor. Using SK-MEL-1 as a model, we found that the mechanism of cell death involves (i) the generation of reactive oxygen species, (ii) activation of the extrinsic and intrinsic apoptotic and mitogen-activated protein kinase pathways, (iii) upregulation of TRAIL, DR4 and DR5, (iv) downregulation of p21Cip1/WAF1 and, inhibition of the NF-κB pathway. 相似文献