Incremental Learning Method for Data with Delayed Labels

Most research on machine learning tasks relies on the availability of true labels immediately after making a prediction. However, in many cases, the ground truth labels become available with a non-negligible delay. In general, delayed labels create two problems. First, labelled data is insufficient because the label for each data chunk will be obtained multiple times. Second, there remains a problem of concept drift due to the long period of data. In this work, we propose a novel incremental ensemble learning when delayed labels occur. First, we build a sliding time window to preserve the historical data. Then we train an adaptive classifier by labelled data in the sliding time window. It is worth noting that we improve the TrAdaBoost to expand the data of the latest moment when building an adaptive classifier. It can correctly distinguish the wrong types of source domain sample classification. Finally, we integrate the various classifiers to make predictions. We apply our algorithms to synthetic and real credit scoring datasets. The experiment results indicate our algorithms have superiority in delayed labelling setting

Robust Small Target Co-Detection from Airborne Infrared Image Sequences

In this paper, a novel infrared target co-detection model combining the self-correlation features of backgrounds and the commonality features of targets in the spatio-temporal domain is proposed to detect small targets in a sequence of infrared images with complex backgrounds. Firstly, a dense target extraction model based on nonlinear weights is proposed, which can better suppress background of images and enhance small targets than weights of singular values. Secondly, a sparse target extraction model based on entry-wise weighted robust principal component analysis is proposed. The entry-wise weight adaptively incorporates structural prior in terms of local weighted entropy, thus, it can extract real targets accurately and suppress background clutters efficiently. Finally, the commonality of targets in the spatio-temporal domain are used to construct target refinement model for false alarms suppression and target confirmation. Since real targets could appear in both of the dense and sparse reconstruction maps of a single frame, and form trajectories after tracklet association of consecutive frames, the location correlation of the dense and sparse reconstruction maps for a single frame and tracklet association of the location correlation maps for successive frames have strong ability to discriminate between small targets and background clutters. Experimental results demonstrate that the proposed small target co-detection method can not only suppress background clutters effectively, but also detect targets accurately even if with target-like interference

Beyond-Birthday-Bound Security for 4-round Linear Substitution-Permutation Networks

Recent works of Cogliati et al. (CRYPTO 2018) have initiated provable treatments of Substitution-Permutation Networks (SPNs), one of the most popular approach to construct modern blockciphers. Such theoretical SPN models may employ non-linear diffusion layers, which enables beyond-birthday-bound provable security. Though, for the model of real world blockciphers, i.e., SPN models with linear diffusion layers, existing provable results are capped at birthday security up to 2n/2 adversarial queries, where n is the size of the idealized S-boxes.In this paper, we overcome this birthday barrier and prove that a 4-round SPN with linear diffusion layers and independent round keys is secure up to 22n/3 queries. For this, we identify conditions on the linear layers that are sufficient for such security, which, unsurprisingly, turns out to be slightly stronger than Cogliati et al.’s conditions for birthday security. These provides additional theoretic supports for real world SPN blockciphers

Ind. Eng. Chem. Res.

Petroleum residue cracking combined coke gasification (RCCG) process was proposed to regenerate the catalyst via coke-steam gasification for syngas production, thus to solve the problem of excessive heat generated via coke combustion in the industrial fluid catalytic cracking (FCC) process. A commercial FCC catalyst and a bifunctional (BF) catalyst were used as the candidates for the RCCG process, and the BF catalyst was specially designed with both catalytic effects of oil cracking and coke gasification. The regeneration characteristics and kinetics of FCC and BF catalysts were studied using a micro fluidized bed. The results showed that high-quality syngas was produced when regenerating the catalysts via steam gasification and the sum of H-2 and CO in the produced gas was over 80 vol % under electrically heated condition.The gasification rate first increased with increasing carbon conversion and then slowly decreased. In comparison with FCC catalyst, the regeneration time of BF catalyst was shortened by more than 30% via addition of alkaline metal oxides and adjustment of its pore size. Homogenous model (HM) and shrinking core model (SCM) were used to calculate the regeneration kinetic parameters of coked catalysts. It was found that the activation energies from these two models were close to each other, while HM had a better fitting relevance for the data than SCM. The activation energy of BF catalyst regeneration was about 115 kJ.mol(-1), lower than that of FCC catalyst (150 kJ.mol(-1)), demonstrating that BF catalyst was easier to regenerate via coke gasification and also justified its bifunctional characteristics. The activation energy of coke gasification on BF catalyst could be further decreased to 45 kJ.mol(-1) when introducing 3% oxygen as the gasification reagent.Petroleum residue cracking combined coke gasification (RCCG) process was proposed to regenerate the catalyst via coke-steam gasification for syngas production, thus to solve the problem of excessive heat generated via coke combustion in the industrial fluid catalytic cracking (FCC) process. A commercial FCC catalyst and a bifunctional (BF) catalyst were used as the candidates for the RCCG process, and the BF catalyst was specially designed with both catalytic effects of oil cracking and coke gasification. The regeneration characteristics and kinetics of FCC and BF catalysts were studied using a micro fluidized bed. The results showed that high-quality syngas was produced when regenerating the catalysts via steam gasification and the sum of H-2 and CO in the produced gas was over 80 vol % under electrically heated condition.The gasification rate first increased with increasing carbon conversion and then slowly decreased. In comparison with FCC catalyst, the regeneration time of BF catalyst was shortened by more than 30% via addition of alkaline metal oxides and adjustment of its pore size. Homogenous model (HM) and shrinking core model (SCM) were used to calculate the regeneration kinetic parameters of coked catalysts. It was found that the activation energies from these two models were close to each other, while HM had a better fitting relevance for the data than SCM. The activation energy of BF catalyst regeneration was about 115 kJ.mol(-1), lower than that of FCC catalyst (150 kJ.mol(-1)), demonstrating that BF catalyst was easier to regenerate via coke gasification and also justified its bifunctional characteristics. The activation energy of coke gasification on BF catalyst could be further decreased to 45 kJ.mol(-1) when introducing 3% oxygen as the gasification reagent

Reactivity and kinetics for steam gasification of petroleum coke blended with black liquor in a micro fluidized bed

Steam gasification of petroleum coke catalyzed by black liquor (BL) was conducted in a micro fluidized bed to investigate the reaction characteristics and kinetics, including the effects of temperature, particle size, BL loading amount and oxygen content in steam on product gas composition and reaction rate. The completion time of petroleum coke steam gasification at 900 degrees C decreased from 120 min for pure coke to about 40 min for the coke blended with 10 wt.% BL The corresponding hydrogen fraction in the produced syngas increased by 9 vol.%. The gasification reaction was further enhanced by introducing a small amount of oxygen into the steam. The shrinking core model (SCM) and homogenous model (HM) were used to calculate the kinetics of petroleum coke gasification, finding that SCM enabled the better correlation with experimental data than HM did. Using SCM the activation energy was 77 kJ.mol(-1) for coke gasification with 10 wt.% BL as catalyst, which was much lower than 120 kJ.mol(-1) for the case without BL blended. The activation energy was further reduced to about 63 kJ-mol(-1) by adding 5% oxygen into the steam, showing a synergistic effects of BL and O-2 on petroleum coke gasification. The study also justified the feasibility of syngas production from petroleum coke via fluidized bed gasification. (C) 2015 Elsevier Ltd. All rights reserved

Identification of a Novel Variant of PDGFC Associated with Nonsyndromic Cleft Lip and Palate in a Chinese Family

Nonsyndromic cleft lip with or without cleft palate (NSCL/P) accounts for 70% of the total number of patients with cleft lip with or without cleft palate (CL/P) and is the most common type of congenital deformity of the craniomaxillofacial region. In this study, whole exome sequencing (WES) and Sanger sequencing were performed on affected members of a Han Chinese family, and a missense variant in the platelet-derived growth factor C (PDGFC) gene (NM_016205: c.G93T: p.Q31H) was identified to be associated with NSCL/P. Bioinformatic studies demonstrated that the amino acid corresponding to this variation is highly conserved in many mammals and leads to a glutamine-to-histidine substitution in an evolutionarily conserved DNA-binding domain. It was found that the expression of PDGFC was significantly decreased in the dental pulp stem cells (DPSCs) of NSCL/P cases, compared to the controls, and that the variant (NM_016205: c.G93T) reduced the expression of PDGFC. In addition, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that Pdgfc deficiency disrupted NSCL/P-related signaling pathways such as the MAPK signaling pathway and cell adhesion molecules. In conclusion, our study identified a missense variant (NM_016205: c.G93T) in exon 1 of PDGFC potentially associated with susceptibility to NSCL/P