pwc-archive/papers-with-abstracts huggingface dataset:
Global Pixel Transformers for Virtual Staining of Microscopy Images
Authors: Yi Liu, Hao Yuan, Zhengyang Wang, Shuiwang Ji
Date: 2019-07-01 00:00:00
Tasks: Virtual Staining

Visualizing the details of different cellular structures is of great importance to elucidate cellular functions. However, it is challenging to obtain high quality images of different structures directly due to complex cellular environments. Fluorescence staining is a popular technique to label different structures but has several drawbacks. In particular, label staining is time consuming and may affect cell morphology, and simultaneous labels are inherently limited. This raises the need of building computational models to learn relationships between unlabeled microscopy images and labeled fluorescence images, and to infer fluorescence labels of other microscopy images excluding the physical staining process. We propose to develop a novel deep model for virtual staining of unlabeled microscopy images. We first propose a novel network layer, known as the global pixel transformer layer, that fuses global information from inputs effectively. The proposed global pixel transformer layer can generate outputs with arbitrary dimensions, and can be employed for all the regular, down-sampling, and up-sampling operators. We then incorporate our proposed global pixel transformer layers and dense blocks to build an U-Net like network. We believe such a design can promote feature reusing between layers. In addition, we propose a multi-scale input strategy to encourage networks to capture features at different scales. We conduct evaluations across various fluorescence image prediction tasks to demonstrate the effectiveness of our approach. Both quantitative and qualitative results show that our method outperforms the state-of-the-art approach significantly. It is also shown that our proposed global pixel transformer layer is useful to improve the fluorescence image prediction results.
Multi-objective multi-generation Gaussian process optimizer for design optimization
Authors: Xiaobiao Huang, Minghao Song, Zhe Zhang
Date: 2019-06-29 00:00:00
Tasks: regression

We present a multi-objective evolutionary optimization algorithm that uses Gaussian process (GP) regression-based models to select trial solutions in a multi-generation iterative procedure. In each generation, a surrogate model is constructed for each objective function with the sample data. The models are used to evaluate solutions and to select the ones with a high potential before they are evaluated on the actual system. Since the trial solutions selected by the GP models tend to have better performance than other methods that only rely on random operations, the new algorithm has much higher efficiency in exploring the parameter space. Simulations with multiple test cases show that the new algorithm has a substantially higher convergence speed and stability than NSGA-II, MOPSO, and some other more recent algorithms.
On-chip learning in a conventional silicon MOSFET based Analog Hardware Neural Network
Authors: Nilabjo Dey, Janak Sharda, Utkarsh Saxena, Divya Kaushik, Utkarsh Singh, Debanjan Bhowmik
Date: 2019-07-01 00:00:00

On-chip learning in a crossbar array based analog hardware Neural Network (NN) has been shown to have major advantages in terms of speed and energy compared to training NN on a traditional computer. However analog hardware NN proposals and implementations thus far have mostly involved Non Volatile Memory (NVM) devices like Resistive Random Access Memory (RRAM), Phase Change Memory (PCM), spintronic devices or floating gate transistors as synapses. Fabricating systems based on RRAM, PCM or spintronic devices need in-house laboratory facilities and cannot be done through merchant foundries, unlike conventional silicon based CMOS chips. Floating gate transistors need large voltage pulses for weight update, making on-chip learning in such systems energy inefficient. This paper proposes and implements through SPICE simulations on-chip learning in analog hardware NN using only conventional silicon based MOSFETs (without any floating gate) as synapses since they are easy to fabricate. We first model the synaptic characteristic of our single transistor synapse using SPICE circuit simulator and benchmark it against experimentally obtained current-voltage characteristics of a transistor. Next we design a Fully Connected Neural Network (FCNN) crossbar array using such transistor synapses. We also design analog peripheral circuits for neuron and synaptic weight update calculation, needed for on-chip learning, again using conventional transistors. Simulating the entire system on SPICE simulator, we obtain high training and test accuracy on the standard Fisher's Iris dataset, widely used in machine learning. We also compare the speed and energy performance of our transistor based implementation of analog hardware NN with some previous implementations of NN with NVM devices and show comparable performance with respect to on-chip learning.
A Power Efficient Artificial Neuron Using Superconducting Nanowires
Authors: Emily Toomey, Ken Segall, Karl K. Berggren
Date: 2019-06-29 00:00:00

With the rising societal demand for more information-processing capacity with lower power consumption, alternative architectures inspired by the parallelism and robustness of the human brain have recently emerged as possible solutions. In particular, spiking neural networks (SNNs) offer a bio-realistic approach, relying on pulses analogous to action potentials as units of information. While software encoded networks provide flexibility and precision, they are often computationally expensive. As a result, hardware SNNs based on the spiking dynamics of a device or circuit represent an increasingly appealing direction. Here, we propose to use superconducting nanowires as a platform for the development of an artificial neuron. Building on an architecture first proposed for Josephson junctions, we rely on the intrinsic nonlinearity of two coupled nanowires to generate spiking behavior, and use electrothermal circuit simulations to demonstrate that the nanowire neuron reproduces multiple characteristics of biological neurons. Furthermore, by harnessing the nonlinearity of the superconducting nanowire's inductance, we develop a design for a variable inductive synapse capable of both excitatory and inhibitory control. We demonstrate that this synapse design supports direct fanout, a feature that has been difficult to achieve in other superconducting architectures, and that the nanowire neuron's nominal energy performance is competitive with that of current technologies.
Fully-Asynchronous Fully-Implicit Variable-Order Variable-Timestep Simulation of Neural Networks
Authors: Bruno Magalhães, Michael Hines, Thomas Sterling, Felix Schuermann
Date: 2019-07-01 00:00:00

State-of-the-art simulations of detailed neural models follow the Bulk Synchronous Parallel execution model. Execution is divided in equidistant communication intervals, equivalent to the shortest synaptic delay in the network. Neurons stepping is performed independently, with collective communication guiding synchronization and exchange of synaptic events. The interpolation step size is fixed and chosen based on some prior knowledge of the fastest possible dynamics in the system. However, simulations driven by stiff dynamics or a wide range of time scales - such as multiscale simulations of neural networks - struggle with fixed step interpolation methods, yielding excessive computation of intervals of quasi-constant activity, inaccurate interpolation of periods of high volatility solution, and being incapable of handling unknown or distinct time constants. A common alternative is the usage of adaptive stepping methods, however they have been deemed inefficient in parallel executions due to computational load imbalance at the synchronization barriers that characterize the BSP execution model. We introduce a distributed fully-asynchronous execution model that removes global synchronization, allowing for longer variable timestep interpolations. Asynchronicity is provided by active point-to-point communication notifying neurons' time advancement to synaptic connectivities. Time stepping is driven by scheduled neuron advancements based on synaptic delays across neurons, yielding an "exhaustive yet not speculative" adaptive-step execution. Execution benchmarks on 64 Cray XE6 compute nodes demonstrate a reduced number of interpolation steps, higher numerical accuracy and lower time to solution, compared to state-of-the-art methods. Efficiency is shown to be activity-dependent, with scaling of the algorithm demonstrated on a simulation of a laboratory experiment.
Application and Computation of Probabilistic Neural Plasticity
Authors: Soaad Hossain
Date: 2019-05-25 00:00:00

The discovery of neural plasticity has proved that throughout the life of a human being, the brain reorganizes itself through forming new neural connections. The formation of new neural connections are achieved through the brain's effort to adapt to new environments or to changes in the existing environment. Despite the realization of neural plasticity, there is a lack of understanding the probability of neural plasticity occurring given some event. Using ordinary differential equations, neural firing equations and spike-train statistics, we show how an additive short-term memory (STM) equation can be formulated to approach the computation of neural plasticity. We then show how the additive STM equation can be used for probabilistic inference in computable neural plasticity, and the computation of probabilistic neural plasticity. We will also provide a brief introduction to the theory of probabilistic neural plasticity and conclude with showing how it can be applied to multiple disciplines such as behavioural science, machine learning, artificial intelligence and psychiatry.
Quantum-Assisted Genetic Algorithm
Authors: James King, Masoud Mohseni, William Bernoudy, Alexandre Fréchette, Hossein Sadeghi, Sergei V. Isakov, Hartmut Neven, Mohammad H. Amin
Date: 2019-06-24 00:00:00

Genetic algorithms, which mimic evolutionary processes to solve optimization problems, can be enhanced by using powerful semi-local search algorithms as mutation operators. Here, we introduce reverse quantum annealing, a class of quantum evolutions that can be used for performing families of quasi-local or quasi-nonlocal search starting from a classical state, as novel sources of mutations. Reverse annealing enables the development of genetic algorithms that use quantum fluctuation for mutations and classical mechanisms for the crossovers -- we refer to these as Quantum-Assisted Genetic Algorithms (QAGAs). We describe a QAGA and present experimental results using a D-Wave 2000Q quantum annealing processor. On a set of spin-glass inputs, standard (forward) quantum annealing finds good solutions very quickly but struggles to find global optima. In contrast, our QAGA proves effective at finding global optima for these inputs. This successful interplay of non-local classical and quantum fluctuations could provide a promising step toward practical applications of Noisy Intermediate-Scale Quantum (NISQ) devices for heuristic discrete optimization.
Incorporating characteristics of human creativity into an evolutionary art algorithm
Authors: Steve DiPaola, Liane Gabora
Date: 2010-01-09 00:00:00

A perceived limitation of evolutionary art and design algorithms is that they rely on human intervention; the artist selects the most aesthetically pleasing variants of one generation to produce the next. This paper discusses how computer generated art and design can become more creatively human-like with respect to both process and outcome. As an example of a step in this direction, we present an algorithm that overcomes the above limitation by employing an automatic fitness function. The goal is to evolve abstract portraits of Darwin, using our 2nd generation fitness function which rewards genomes that not just produce a likeness of Darwin but exhibit certain strategies characteristic of human artists. We note that in human creativity, change is less choosing amongst randomly generated variants and more capitalizing on the associative structure of a conceptual network to hone in on a vision. We discuss how to achieve this fluidity algorithmically.
An Agent-based Simulation of the Effectiveness of Creative Leadership
Authors: Stefan Leijnen, Liane Gabora
Date: 2010-05-10 00:00:00
Tasks: Diversity

This paper investigates the effectiveness of creative versus uncreative leadership using EVOC, an agent-based model of cultural evolution. Each iteration, each agent in the artificial society invents a new action, or imitates a neighbor's action. Only the leader's actions can be imitated by all other agents, referred to as followers. Two measures of creativity were used: (1) invention-to-imitation ratio, iLeader, which measures how often an agent invents, and (2) rate of conceptual change, cLeader, which measures how creative an invention is. High iLeader increased mean fitness of ideas, but only when creativity of followers was low. High iLeader was associated with greater diversity of ideas in the early stage of idea generation only. High cLeader increased mean fitness of ideas in the early stage of idea generation; in the later stage it decreased idea fitness. Reasons for these findings and tentative implications for creative leadership in human society are discussed.
Progressive Fashion Attribute Extraction
Authors: Sandeep Singh Adhikari, Sukhneer Singh, Anoop Rajagopal, Aruna Rajan
Date: 2019-06-29 00:00:00
Tasks: All, Articles, Attribute, Attribute Extraction, Classification, General Classification, Multi-class Classification, Multi-Label Classification, MUlTI-LABEL-ClASSIFICATION

Extracting fashion attributes from images of people wearing clothing/fashion accessories is a very hard multi-class classification problem. Most often, even catalogues of fashion do not have all the fine-grained attributes tagged due to prohibitive cost of annotation. Using images of fashion articles, running multi-class attribute extraction with a single model for all kinds of attributes (neck design detailing, sleeves detailing, etc) requires classifiers that are robust to missing and ambiguously labelled data. In this work, we propose a progressive training approach for such multi-class classification, where weights learnt from an attribute are fine tuned for another attribute of the same fashion article (say, dresses). We branch networks for each attributes from a base network progressively during training. While it may have many labels, an image doesn't need to have all possible labels for fashion articles present in it. We also compare our approach to multi-label classification, and demonstrate improvements over overall classification accuracies using our approach.
Continual Learning for Robotics: Definition, Framework, Learning Strategies, Opportunities and Challenges
Authors: Timothée Lesort, Vincenzo Lomonaco, Andrei Stoian, Davide Maltoni, David Filliat, Natalia Díaz-Rodríguez
Date: 2019-06-29 00:00:00
Tasks: BIG-bench Machine Learning, Continual Learning

Continual learning (CL) is a particular machine learning paradigm where the data distribution and learning objective changes through time, or where all the training data and objective criteria are never available at once. The evolution of the learning process is modeled by a sequence of learning experiences where the goal is to be able to learn new skills all along the sequence without forgetting what has been previously learned. Continual learning also aims at the same time at optimizing the memory, the computation power and the speed during the learning process. An important challenge for machine learning is not necessarily finding solutions that work in the real world but rather finding stable algorithms that can learn in real world. Hence, the ideal approach would be tackling the real world in a embodied platform: an autonomous agent. Continual learning would then be effective in an autonomous agent or robot, which would learn autonomously through time about the external world, and incrementally develop a set of complex skills and knowledge. Robotic agents have to learn to adapt and interact with their environment using a continuous stream of observations. Some recent approaches aim at tackling continual learning for robotics, but most recent papers on continual learning only experiment approaches in simulation or with static datasets. Unfortunately, the evaluation of those algorithms does not provide insights on whether their solutions may help continual learning in the context of robotics. This paper aims at reviewing the existing state of the art of continual learning, summarizing existing benchmarks and metrics, and proposing a framework for presenting and evaluating both robotics and non robotics approaches in a way that makes transfer between both fields easier.
An Overview of the Ludii General Game System
Authors: Matthew Stephenson, Éric Piette, Dennis J. N. J. Soemers, Cameron Browne
Date: 2019-06-29 00:00:00

The Digital Ludeme Project (DLP) aims to reconstruct and analyse over 1000 traditional strategy games using modern techniques. One of the key aspects of this project is the development of Ludii, a general game system that will be able to model and play the complete range of games required by this project. Such an undertaking will create a wide range of possibilities for new AI challenges. In this paper we describe many of the features of Ludii that can be used. This includes designing and modifying games using the Ludii game description language, creating agents capable of playing these games, and several advantages the system has over prior general game software.
An Empirical Evaluation of Two General Game Systems: Ludii and RBG
Authors: Éric Piette, Matthew Stephenson, Dennis J. N. J. Soemers, Cameron Browne
Date: 2019-06-29 00:00:00
Tasks: Vocal Bursts Valence Prediction

Although General Game Playing (GGP) systems can facilitate useful research in Artificial Intelligence (AI) for game-playing, they are often computationally inefficient and somewhat specialised to a specific class of games. However, since the start of this year, two General Game Systems have emerged that provide efficient alternatives to the academic state of the art -- the Game Description Language (GDL). In order of publication, these are the Regular Boardgames language (RBG), and the Ludii system. This paper offers an experimental evaluation of Ludii. Here, we focus mainly on a comparison between the two new systems in terms of two key properties for any GGP system: simplicity/clarity (e.g. human-readability), and efficiency.
Ludii and XCSP: Playing and Solving Logic Puzzles
Authors: Cédric Piette, Éric Piette, Matthew Stephenson, Dennis J. N. J. Soemers, Cameron Browne
Date: 2019-06-29 00:00:00

Many of the famous single-player games, commonly called puzzles, can be shown to be NP-Complete. Indeed, this class of complexity contains hundreds of puzzles, since people particularly appreciate completing an intractable puzzle, such as Sudoku, but also enjoy the ability to check their solution easily once it's done. For this reason, using constraint programming is naturally suited to solve them. In this paper, we focus on logic puzzles described in the Ludii general game system and we propose using the XCSP formalism in order to solve them with any CSP solver.
Ludii as a Competition Platform
Authors: Matthew Stephenson, Éric Piette, Dennis J. N. J. Soemers, Cameron Browne
Date: 2019-06-29 00:00:00

Ludii is a general game system being developed as part of the ERC-funded Digital Ludeme Project (DLP). While its primary aim is to model, play, and analyse the full range of traditional strategy games, Ludii also has the potential to support a wide range of AI research topics and competitions. This paper describes some of the future competitions and challenges that we intend to run using the Ludii system, highlighting some of its most important aspects that can potentially lead to many algorithm improvements and new avenues of research. We compare and contrast our proposed competition motivations, goals and frameworks against those of existing general game playing competitions, addressing the strengths and weaknesses of each platform.
Multi-Armed Bandits with Fairness Constraints for Distributing Resources to Human Teammates
Authors: Houston Claure, Yifang Chen, Jignesh Modi, Malte Jung, Stefanos Nikolaidis
Date: 2019-06-30 00:00:00
Tasks: Fairness, Multi-Armed Bandits, Reinforcement Learning

How should a robot that collaborates with multiple people decide upon the distribution of resources (e.g. social attention, or parts needed for an assembly)? People are uniquely attuned to how resources are distributed. A decision to distribute more resources to one team member than another might be perceived as unfair with potentially detrimental effects for trust. We introduce a multi-armed bandit algorithm with fairness constraints, where a robot distributes resources to human teammates of different skill levels. In this problem, the robot does not know the skill level of each human teammate, but learns it by observing their performance over time. We define fairness as a constraint on the minimum rate that each human teammate is selected throughout the task. We provide theoretical guarantees on performance and perform a large-scale user study, where we adjust the level of fairness in our algorithm. Results show that fairness in resource distribution has a significant effect on users' trust in the system.
A Novel Bi-directional Interrelated Model for Joint Intent Detection and Slot Filling
Authors: Haihong E, Peiqing Niu, Zhongfu Chen, Meina Song
Date: 2019-06-30 00:00:00
Proceeding: ACL 2019 7
Tasks: Intent Detection, Sentence, slot-filling, Slot Filling, Spoken Language Understanding

A spoken language understanding (SLU) system includes two main tasks, slot filling (SF) and intent detection (ID). The joint model for the two tasks is becoming a tendency in SLU. But the bi-directional interrelated connections between the intent and slots are not established in the existing joint models. In this paper, we propose a novel bi-directional interrelated model for joint intent detection and slot filling. We introduce an SF-ID network to establish direct connections for the two tasks to help them promote each other mutually. Besides, we design an entirely new iteration mechanism inside the SF-ID network to enhance the bi-directional interrelated connections. The experimental results show that the relative improvement in the sentence-level semantic frame accuracy of our model is 3.79% and 5.42% on ATIS and Snips datasets, respectively, compared to the state-of-the-art model.
Prediction is very hard, especially about conversion. Predicting user purchases from clickstream data in fashion e-commerce
Authors: Luca Bigon, Giovanni Cassani, Ciro Greco, Lucas Lacasa, Mattia Pavoni, Andrea Polonioli, Jacopo Tagliabue
Date: 2019-06-30 00:00:00

Knowing if a user is a buyer vs window shopper solely based on clickstream data is of crucial importance for ecommerce platforms seeking to implement real-time accurate NBA (next best action) policies. However, due to the low frequency of conversion events and the noisiness of browsing data, classifying user sessions is very challenging. In this paper, we address the clickstream classification problem in the fashion industry and present three major contributions to the burgeoning field of AI in fashion: first, we collected, normalized and prepared a novel dataset of live shopping sessions from a major European e-commerce fashion website; second, we use the dataset to test in a controlled environment strong baselines and SOTA models from the literature; finally, we propose a new discriminative neural model that outperforms neural architectures recently proposed at Rakuten labs.