Goal-oriented Dialogue Policy Learning from Failures

Reinforcement learning methods have been used for learning dialogue policies. However, learning an effective dialogue policy frequently requires prohibitively many conversations. This is partly because of the sparse rewards in dialogues, and the very few successful dialogues in early learning phase. Hindsight experience replay (HER) enables learning from failures, but the vanilla HER is inapplicable to dialogue learning due to the implicit goals. In this work, we develop two complex HER methods providing different trade-offs between complexity and performance, and, for the first time, enabled HER-based dialogue policy learning. Experiments using a realistic user simulator show that our HER methods perform better than existing experience replay methods (as applied to deep Q-networks) in learning rate

Antioxidants and dehydrin metabolism associated with osmopriming-enhanced stress tolerance of germinating spinach (Spinacia oleracea L. cv. Bloomsdale) seeds

Osmopriming is a pre-soaking treatment that improves seed germination performance as well as stress tolerance. In this study, we use spinach (Spinacia oleracea cv. Bloomsdale) as the model to study cellular mechanisms contributing to the improved stress tolerance during post-priming germination. We first determined an optimal osmopriming protocol for `Bloomsdale\u27 spinach, i.e. priming seeds with -0.6 MPa PEG 8000 at 15 yC for 8 d. This protocol also improved germinating seeds\u27 tolerance to temperature (sub- and supra-temperature) and desiccation stress. To explore the biochemistry contributing to the priming-induced stress tolerance, we examined two extensively studied stress-responsive components: antioxidant system and dehydrins. An update of `antioxidant system\u27 was found during osmopriming and early germination stage, as manifested in the repression of antioxidants involved in seed protection during dry storage, and enhancement of those related to seed germinability. Possibly, this system update was resulted from the transition of seeds from dry to imbibing / germinating state. Osmopriming might provide a `head-start\u27 for this transition, and thus resulted in a more robust antioxidant system in primed seeds and increased their germination potential. Consequently, primed seeds exhibited improve tolerance to chilling and desiccation stress. Our study of dehydrin accumulation, on the other hand, suggests an alternative strategy for osmopriming to improve stress tolerance in germinating seeds. Several dehydrins (30, 26, and 19-kD dehydrins, and CAP85) transiently accumulated during osmopriming at both protein and transcript levels. These dehydrins also re-accumulated in primed seeds in response to chilling and desiccation stress, and thus may be associated with the improved stress tolerance. It is possible that osmopriming imposed mild osmotic stress in seeds and induced accumulation of stress responses (dehydrins) to confer cross-tolerance that rendered primed seeds more tolerant to subsequent stress exposures. We assumed that osmopriming might use the above-described two strategies (i.e. increasing seed germination potential and inducing cross-tolerance in seeds) that act together to enhance seed stress tolerance during post-priming germination

Toddler Play Preferences and the Teacher’s Role in the Outdoor Play Environment

Direct experience with nature is a primary component of environmental education and especially beneficial for young children. The present study examined the outdoor play preferences of toddlers and investigated the role teachers play in the outdoor space. Toddlers’ outdoor play was video recorded by GoPro cameras and coded for preferred play locations and initiator of the play. Results showed that the three most preferred spaces for toddlers in the outdoor classroom were the sandbox, swing area, and play structures; least frequently visited were open areas close to the classrooms, the garden, and the tree area. In addition, toddlers initiated play 71% of the time whereas teachers initiated approximately 11% of the time and mostly in the swing area. Findings indicate that teachers may play a role in where toddlers prefer to play. Implications for teacher preparation regarding environmental education are discussed

Learning and Reasoning for Robot Dialog and Navigation Tasks

You are viewing an article from the Proceedings of the 21st Annual Meeting of the Special Interest Group on Discourse and Dialogue that was in the Good Systems Network Digest in 2020.Office of the VP for Researc

New Impossible Differential Attacks of Reduced-Round Camellia-192 and Camellia-256

Camellia is a block cipher selected as a standard by ISO/IEC, which has been analyzed by a number of cryptanalysts. In this paper, we propose several 6-round impossible differential paths of Camellia with the $FL/FL^{-1}$ layer in the middle of them. With the impossible differential and a well-organized precomputational table, impossible differential attacks on 10-round Camellia-192 and 11-round Camellia-256 are given, and the time complexity are $2^{175}$ and $2^{206.8}$ respectively. An impossible differential attack on 15-round Camellia-256 without $FL/FL^{-1}$ layers and whitening is also be given, which needs about $2^{236.1}$ encryptions. To the best of our knowledge, these are the best cryptanalytic results of Camellia-192/-256 with $FL/FL^{-1}$ layers and Camellia-256 without $FL/FL^{-1}$ layers to date

Near-Collision Attack on the Step-Reduced Compression Function of Skein-256

The Hash function Skein is one of the 5 finalists of NIST SHA-3 competition. It is designed based on the threefish block cipher and it only uses three primitive operations: modular addition, rotation and bitwise XOR (ARX). In this paper, we combine two short differential paths to a long differential path using the modular differential technique. And we present the semi-free start near-collision attack up to the 32-step Skein-256 with the Hamming difference 51. The complexity of our attack is about $2^{105}$

Practical-time Attack on the Full MMB Block Cipher

Modular Multiplication based Block Cipher (MMB) is a block cipher designed by Daemen \emph{et al.} as an alternative to the IDEA block cipher. In this paper, we give a practical-time attack on the full MMB with adaptive chosen plaintexts and ciphertexts. By the constructive sandwich distinguisher for 5 of the 6 rounds of MMB with amazingly high probability 1, we give the key recovery attack on the full MMB with data complexity $2^{40}$ and time complexity $2^{13.4}$ MMB encryptions. Then a rectangle-like sandwich attack on the full MMB is presented, with $2^{66.5}$ chosen plaintexts, $2^{64}$ MMB encryptions and $2^{70.5}$ memory bytes. By the way, we show an improved differential attack on the full MMB with data complexity of $2^{96}$ chosen plaintexts and ciphertexts, time complexity $2^{64}$ encryptions and $2^{66}$ bytes of memory