3,021 research outputs found
Belief Tree Search for Active Object Recognition
Active Object Recognition (AOR) has been approached as an unsupervised
learning problem, in which optimal trajectories for object inspection are not
known and are to be discovered by reducing label uncertainty measures or
training with reinforcement learning. Such approaches have no guarantees of the
quality of their solution. In this paper, we treat AOR as a Partially
Observable Markov Decision Process (POMDP) and find near-optimal policies on
training data using Belief Tree Search (BTS) on the corresponding belief Markov
Decision Process (MDP). AOR then reduces to the problem of knowledge transfer
from near-optimal policies on training set to the test set. We train a Long
Short Term Memory (LSTM) network to predict the best next action on the
training set rollouts. We sho that the proposed AOR method generalizes well to
novel views of familiar objects and also to novel objects. We compare this
supervised scheme against guided policy search, and find that the LSTM network
reaches higher recognition accuracy compared to the guided policy method. We
further look into optimizing the observation function to increase the total
collected reward of optimal policy. In AOR, the observation function is known
only approximately. We propose a gradient-based method update to this
approximate observation function to increase the total reward of any policy. We
show that by optimizing the observation function and retraining the supervised
LSTM network, the AOR performance on the test set improves significantly.Comment: IROS 201
Against Hayek
Presents a critical analysis of Hayek in the light of modern computability and economic computability theory.Hayek, Computability, Socialism
Investigation to define the propagation characteristics of a finite amplitude acoustic pressure wave Final report
Aerodynamic noise generation by finite amplitude pressure wave propagation through entropy producing region
Investigation to define the propagation characteristics of a finite amplitude acoustic pressure wave
A theoretical analysis of the propagation characteristics of a finite amplitude pressure wave is presented. The analysis attempts to study the contribution of entropy-producing regions to the mechanism of aerodynamic noise generation. It results in a nonlinear convective wave equation in terms of entropy and a thermodynamic 'J' function. A direct analogy between the derived governing equation and those used in classical literature is obtained. An idealization of the processes considered permits the uncoupling of the equations of motion with a consequent construction of an acoustic analogy treating shock wave emission of finite amplitude acoustic waves. An engineering approach is reflected in the concept of an extended plug nozzle whose function is to facilitate aerodynamic noise attenuation by modifying the entropy-producing regions
EMPATH: A Neural Network that Categorizes Facial Expressions
There are two competing theories of facial expression recognition. Some researchers have suggested that it is an example of "categorical perception." In this view, expression categories are considered to be discrete entities with sharp boundaries, and discrimination of nearby pairs of expressive faces is enhanced near those boundaries. Other researchers, however, suggest that facial expression perception is more graded and that facial expressions are best thought of as points in a continuous, low-dimensional space, where, for instance, "surprise" expressions lie between "happiness" and "fear" expressions due to their perceptual similarity. In this article, we show that a simple yet biologically plausible neural network model, trained to classify facial expressions into six basic emotions, predicts data used to support both of these theories. Without any parameter tuning, the model matches a variety of psychological data on categorization, similarity, reaction times, discrimination, and recognition difficulty, both qualitatively and quantitatively. We thus explain many of the seemingly complex psychological phenomena related to facial expression perception as natural consequences of the tasks' implementations in the brain
Skeleton Key: Image Captioning by Skeleton-Attribute Decomposition
Recently, there has been a lot of interest in automatically generating
descriptions for an image. Most existing language-model based approaches for
this task learn to generate an image description word by word in its original
word order. However, for humans, it is more natural to locate the objects and
their relationships first, and then elaborate on each object, describing
notable attributes. We present a coarse-to-fine method that decomposes the
original image description into a skeleton sentence and its attributes, and
generates the skeleton sentence and attribute phrases separately. By this
decomposition, our method can generate more accurate and novel descriptions
than the previous state-of-the-art. Experimental results on the MS-COCO and a
larger scale Stock3M datasets show that our algorithm yields consistent
improvements across different evaluation metrics, especially on the SPICE
metric, which has much higher correlation with human ratings than the
conventional metrics. Furthermore, our algorithm can generate descriptions with
varied length, benefiting from the separate control of the skeleton and
attributes. This enables image description generation that better accommodates
user preferences.Comment: Accepted by CVPR 201
- …