Oceania
Generating Difficult SAT Instances by Preventing Triangles
Escamocher, Guillaume, O'Sullivan, Barry, Prestwich, Steven David
When creating benchmarks for SAT solvers, we need SAT instances that are easy to build but hard to solve. A recent development in the search for such methods has led to the Balanced SAT algorithm, which can create k-SAT instances with m clauses of high difficulty, for arbitrary k and m. In this paper we introduce the No-Triangle SAT algorithm, a SAT instance generator based on the cluster coefficient graph statistic. We empirically compare the two algorithms by fixing the arity and the number of variables, but varying the number of clauses. The hardest instances that we find are produced by No-Triangle SAT. Furthermore, difficult instances from No-Triangle SAT have a different number of clauses than difficult instances from Balanced SAT, potentially allowing a combination of the two methods to find hard SAT instances for a larger array of parameters.
Incorporating social practices in BDI agent systems
Cranefield, Stephen, Dignum, Frank
When agents interact with humans, either through embodied agents or because they are embedded in a robot, it would be easy if they could use fixed interaction protocols as they do with other agents. However, people do not keep fixed protocols in their day-to-day interactions and the environments are often dynamic, making it impossible to use fixed protocols. Deliberating about interactions from fundamentals is not very scalable either, because in that case all possible reactions of a user have to be considered in the plans. In this paper we argue that social practices can be used as an inspiration for designing flexible and scalable interaction mechanisms that are also robust. However, using social practices requires extending the traditional BDI deliberation cycle to monitor landmark states and perform expected actions by leveraging existing plans. We define and implement this mechanism in Jason using a periodically run meta-deliberation plan, supported by a metainterpreter, and illustrate its use in a realistic scenario.
SeizureNet: A Deep Convolutional Neural Network for Accurate Seizure Type Classification and Seizure Detection
Asif, Umar, Roy, Subhrajit, Tang, Jianbin, Harrer, Stefan
Automatic epileptic seizure analysis is important because the differentiation of neural patterns among different patients can be used to classify people with specific types of epilepsy. This could enable more efficient management of the disease. Automatic seizure type classification using clinical electroencephalograms (EEGs) is challenging due to factors such as low signal to noise ratios, signal artefacts, high variance in the seizure semiology among individual epileptic patients, and limited clinical data constraints. To overcome these challenges, in this paper, we present a deep learning based framework which uses a Convolutional Neural Network (CNN) with dense connections and learns highly robust features at different spatial and temporal resolutions of the EEG data spectrum for accurate cross-patient seizure type classification. We evaluate our framework for seizure type classification and seizure detection on the recently released TUH EEG Seizure Corpus, where our framework achieves overall weighted f 1 scores of up to 0.90 and 0.88, thereby setting new benchmarks on the dataset.
Learning Hierarchical Teaching in Cooperative Multiagent Reinforcement Learning
Kim, Dong Ki, Liu, Miao, Omidshafiei, Shayegan, Lopez-Cot, Sebastian, Riemer, Matthew, Habibi, Golnaz, Tesauro, Gerald, Mourad, Sami, Campbell, Murray, How, Jonathan P.
Heterogeneous knowledge naturally arises among different agents in cooperative multiagent reinforcement learning. As such, learning can be greatly improved if agents can effectively pass their knowledge on to other agents. Existing work has demonstrated that peer-to-peer knowledge transfer, a process referred to as action advising, improves team-wide learning. In contrast to previous frameworks that advise at the level of primitive actions, we aim to learn high-level teaching policies that decide when and what high-level action (e.g., sub-goal) to advise a teammate. We introduce a new learning to teach framework, called hierarchical multiagent teaching (HMAT). The proposed framework solves difficulties faced by prior work on multiagent teaching when operating in domains with long horizons, delayed rewards, and continuous states/actions by leveraging temporal abstraction and deep function approximation. Our empirical evaluations show that HMAT accelerates team-wide learning progress in difficult environments that are more complex than those explored in previous work. HMAT also learns teaching policies that can be transferred to different teammates/tasks and can even teach teammates with heterogeneous action spaces.
Learning to Speak and Act in a Fantasy Text Adventure Game
Urbanek, Jack, Fan, Angela, Karamcheti, Siddharth, Jain, Saachi, Humeau, Samuel, Dinan, Emily, Rocktรคschel, Tim, Kiela, Douwe, Szlam, Arthur, Weston, Jason
We introduce a large scale crowdsourced text adventure game as a research platform for studying grounded dialogue. In it, agents can perceive, emote, and act whilst conducting dialogue with other agents. Models and humans can both act as characters within the game. We describe the results of training state-of-the-art generative and retrieval models in this setting. We show that in addition to using past dialogue, these models are able to effectively use the state of the underlying world to condition their predictions. In particular, we show that grounding on the details of the local environment, including location descriptions, and the objects (and their affordances) and characters (and their previous actions) present within it allows better predictions of agent behavior and dialogue. We analyze the ingredients necessary for successful grounding in this setting, and how each of these factors relate to agents that can talk and act successfully.
GRATIS: GeneRAting TIme Series with diverse and controllable characteristics
Kang, Yanfei, Hyndman, Rob J, Li, Feng
The explosion of time series data in recent years has brought a flourish of new time series analysis methods, for forecasting, clustering, classification and other tasks. The evaluation of these new methods requires a diverse collection of time series benchmarking data to enable reliable comparisons against alternative approaches. We propose GeneRAting TIme Series with diverse and controllable characteristics, named GRATIS, with the use of mixture autoregressive (MAR) models. We generate sets of time series using MAR models and investigate the diversity and coverage of the generated time series in a time series feature space. By tuning the parameters of the MAR models, GRATIS is also able to efficiently generate new time series with controllable features. In general, as a costless surrogate to the traditional data collection approach, GRATIS can be used as an evaluation tool for tasks such as time series forecasting and classification. We illustrate the usefulness of our time series generation process through a time series forecasting application.
How do we make artificial intelligence more humane?
Too often we're told that if Australia is to compete globally in developing AI products, Australian researchers and companies must not be fettered by human rights concerns, because other countries certainly aren't. China, for example, is investing heavily in AI technology such as facial recognition to support its "social credit score" system, which involves conducting precise and determinative surveillance of its citizens. In the context of a global AI arms race, it is argued, Australia can't compete with one arm tied behind its back.
How AI and cloud technology can shape corporate communications
The costs associated with information technology products and services in Australia are expected to reach A$93 billion in 2019, while 28 per cent of spending within key enterprise IT markets globally is expected to shift to the cloud by 2022. Developments in cloud computing and Artificial Intelligence(AI) have changed what's possible in regard to software services which can be provided to organisations. Each year, solutions powered by the cloud and AI are deployed by enterprise businesses to improve the efficiency of business operations and the productivity of employees. Business communication methods are one area that has and will continue to benefit greatly from improvements in cloud technology and AI. This advance in technology is allowing businesses to seek quicker and more simple communication in an increasingly mobile world.
Don't look now: why you should be worried about machines reading your emotions
Could a program detect potential terrorists by reading their facial expressions and behavior? This was the hypothesis put to the test by the US Transportation Security Administration (TSA) in 2003, as it began testing a new surveillance program called the Screening of Passengers by Observation Techniques program, or Spot for short. While developing the program, they consulted Paul Ekman, emeritus professor of psychology at the University of California, San Francisco. Decades earlier, Ekman had developed a method to identify minute facial expressions and map them on to corresponding emotions. This method was used to train "behavior detection officers" to scan faces for signs of deception.