Adversarial Sampling and Training for Semi-Supervised Information Retrieval

Ad-hoc retrieval models with implicit feedback often have problems, e.g., the imbalanced classes in the data set. Too few clicked documents may hurt generalization ability of the models, whereas too many non-clicked documents may harm effectiveness of the models and efficiency of training. In addition, recent neural network-based models are vulnerable to adversarial examples due to the linear nature in them. To solve the problems at the same time, we propose an adversarial sampling and training framework to learn ad-hoc retrieval models with implicit feedback. Our key idea is (i) to augment clicked examples by adversarial training for better generalization and (ii) to obtain very informational non-clicked examples by adversarial sampling and training. Experiments are performed on benchmark data sets for common ad-hoc retrieval tasks such as Web search, item recommendation, and question answering. Experimental results indicate that the proposed approaches significantly outperform strong baselines especially for high-ranked documents, and they outperform IRGAN in NDCG@5 using only 5% of labeled data for the Web search task.Comment: Published in WWW 201

Superconformal Chern-Simons theories and the squashed seven sphere

We show that there are two supersymmetric completions of the three-dimensional Chern-Simons theory of level k with gauge group U(N) × U(N) coupled to four sets of massless scalars and spinors in the bi-fundamental representation, if we require Sp(2) ⊂ SU(4) global symmetry with the matter fields in the fundamental representation of SU(4). One is the Script N = 6 superconformal theory recently studied in hep-th/0806.1218 and another is a new theory with Script N = 1 superconformal symmetry. We conjecture that the Script N = 1 theory is dual to M theory on AdS4 × squashed S^7/Bbb Zk

Ligand induced cleavage and nuclear localization of the rice XA21 immune receptor

The rice XA21 receptor confers immunity to the Gram-negative bacterial pathogen, _Xanthomonas oryzae_ pv. _oryzae_ (_Xoo_) upon recognition of the conserved microbial signature AxY^S^22. Here, we demonstrate that the intracellular kinase domain of XA21 translocates to the nucleus upon AxY^S^22-mediated perception and that this translocation event is required for XA21-mediated immunity

Clockwork seesaw mechanisms

We propose new mechanisms for small neutrino masses based on clockwork mechanism. The Standard Model neutrinos and lepton number violating operators communicate through the zero mode of clockwork gears, one of the two couplings of the zero mode is exponentially suppressed by clockwork mechanism. Including all known examples for the clockwork realization of the neutrino masses, different types of models are realized depending on the profile and chirality of the zero mode fermion. Each type of realization would have phenomenologically distinctive features with the accompanying heavy neutrinos.Comment: 6 pages, 4 figures, minor revision (discussion and notation improved), matches version accepted in PL