Nigel Crook

Nigel Crook
Oxford Brookes University · Department of Computing and Communication Technologies (CCT)

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43
Publications
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957
Citations

Publications

Publications (43)
Conference Paper
Full-text available
AI and robot ethics have recently gained a lot of attention because adaptive machines are increasingly involved in ethically sensitive scenarios and cause incidents of public outcry. Much of the debate has been focused on achieving highest moral standards in handling ethical dilemmas on which not even humans can agree, which indicates that the wron...
Conference Paper
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This paper presents a study of the movements of a humanoid head-and-neck robot called Eddie. Eddie has a musculo-skeletal structure similar to that found in human necks enabling it to perform head movements that are comparable with human head movements. This study compares the move- ments of Eddie with those of a more conventional robotic neck stru...
Chapter
This paper considers the impact that robot collaboration strategies have on their human collaborators. In particular, we are interested in how robot leader/follower strategies affect perceived safety and perceived intelligence, which, we argue, are essential for establishing trust and enabling true collaboration between human and robot. We propose...
Conference Paper
Full-text available
Future personal robots might possess the capability to autonomously generate novel goals that exceed their initial programming as well as their past experience. We discuss the ethical challenges involved in such a scenario, ranging from the construction of ethics into such machines to the standard of ethics we could actually demand from such machin...
Conference Paper
Full-text available
This paper explores the effect of upper body pose mirroring in human-robot interaction. A group participants is used to evaluate how imitation by a robot affect people's perception of their conversation with it. A set of twelve questions about the participants' university experience serves a backbone for the dialogue structure. In our experimental...
Conference Paper
Full-text available
This paper considers the impact that robot collaboration strategies have on their human collaborators. In particular, we are interested in how robot leader/follower strategies affect perceived safety and perceived intelligence, which, we argue, are essential for establishing trust and enabling true collaboration between human and robot. We propose...
Conference Paper
Full-text available
The behavioural diversity of chaotic oscillator can be controlled into periodic dynamics and used to model locomotion using central pattern generators. This paper shows how controlled chaotic oscil-lators may improve the adaptation of the robot locomotion behaviour to terrain uncertainties when compared to nonlinear harmonic oscilla-tors. This is q...
Article
Full-text available
Humans describe images in terms of nouns and adjectives while algorithms operate on images represented as sets of pixels. Bridging this gap between how humans would like to access images versus their typical representation is the goal of image parsing, which involves assigning object and attribute labels to pixel. In this paper we propose treating...
Article
Full-text available
Chaos provides many interesting properties that can be used to achieve computational tasks. Such properties are sensitivity to initial conditions, space filling, control and synchronization. Chaotic neural models have been devised to exploit such properties. In this paper, a chaotic spiking neuron model is investigated experimentally. This investig...
Conference Paper
Full-text available
Detecting visually salient regions in images is one of the fundamental problems in computer vision. We propose a novel method to decompose an image into large scale perceptually homogeneous elements for efficient salient region detection, using a soft image abstraction representation. By considering both appearance similarity and spatial distributi...
Conference Paper
Full-text available
We propose a generic method for obtaining nonparametric image warps from noisy point correspondences. Our formulation integrates a huber function into a motion coherence framework. This makes our fitting function especially robust to piecewise correspondence noise (where an image section is consistently mismatched). By utilizing over parameterized...
Article
Full-text available
Humans describe images in terms of nouns and adjectives while algorithms operate on images represented as sets of pixels. Bridging this gap between how we would like to access images versus their typical representation is the goal of image parsing. In this paper we propose treating nouns as object labels and adjectives as visual attributes. This al...
Conference Paper
The emergence of affordable depth cameras has enabled significant advances in human segmentation and pose estimation in recent years. While it leads to impressive results in many tasks, the use of infra-red cameras have their drawbacks, in particular the fact that they don’t work in direct sunlight. One alternative is to use a stereo pair of camera...
Conference Paper
Full-text available
Linear SVMs are efficient in both training and testing, however the data in real applications is rarely linearly sep-arable. Non-linear kernel SVMs are too computationally intensive for applications with large-scale data sets. Re-cently, locally linear classifiers have gained popularity due to their efficiency whilst remaining competitive with kern...
Article
Full-text available
We present an Embodied Conversational Agent (ECA) that incorporates a context-sensitive mechanism for handling user barge-in. The affective ECA engages the user in social conversation, and is fully implemented. We will use actual examples of system behaviour to illustrate. The ECA is designed to recognise and be empathetic to the emotional state of...
Conference Paper
Full-text available
Semantic image segmentation is a problem of simultaneous segmentation and recognition of an input image into regions and their associated categorical labels, such as person, car or cow. A popular way to achieve this goal is to assign a label to every pixel in the input image and impose simple structural constraints on the output label space. Effici...
Article
Full-text available
The tasks of stereo matching, segmentation, and human pose estimation have been popular in computer vision in recent years, but attempts to combine the three tasks have so far resulted in compromises: either using infra-red cameras, or a greatly simplified body model. We propose a framework for estimating a detailed human skeleton in 3D from a ster...
Conference Paper
Full-text available
The development of Embodied Conversational Agents (ECA) as Companions brings several challenges for both affective and conversational dialogue. These include challenges in generating appropriate affective responses, selecting the overall shape of the dialogue, providing prompt system response times and handling interruptions. We present an implemen...
Conference Paper
Full-text available
Embodied Conversational Agents (ECA) are poised to constitute a specific category within persuasive systems, in particular through their ability to support affective dialogue. One possible approach consists in using ECA as virtual coaches or personal assistants and to make persuasion part of a dialogue game implementing specific argumentation or ne...
Conference Paper
Full-text available
This paper presents a dialogue system in the form of an ECA that acts as a sociable and emotionally intelligent companion for the user. The system dialogue is not task-driven but is social conversation in which the user talks about his/her day at the office. During conversations the system monitors the emotional state of the user and uses that info...
Conference Paper
Full-text available
Much interest has recently been given to making dialogue systems more natural by implementing more flexible software solutions, such as parallel and incremental processing. In the How-Was-Your-Day prototype, parallel processing paths provide complementary information and the parallel processing loops enable the system to respond to user activity in...
Article
Full-text available
We present a mechanism for handling "barge-in" interrup-tions from a user who is engaged in a 'social' conversation with an Embodied Conversational Agent (ECA). The ECA is designed to recognise and be empathetic to the emotional state of the user. Occasionally, the ECA will attempt to positively influence the user's emotional state through the conv...
Conference Paper
Full-text available
In recent years Dialogue Acts have be- come a popular means of modelling the communicative intentions of human and machine utterances in many modern di- alogue systems. Many of these systems rely heavily on the availability of dialogue corpora that have been annotated with Di- alogue Act labels. The manual annota- tion of dialogue corpora is both t...
Article
Evidence has been found for the presence of chaotic dynamics at all levels of the mammalian brain. This has led to some searching questions about the potential role that nonlinear dynamics may have in neural information processing. We propose that chaos equips the brain with the equivalent of a kernel trick for solving hard nonlinear problems. The...
Article
A novel transient computation device is presented which performs computations on time-varying input signals. The inputs perturb the device causing transients in its internal dynamics. These transients are characteristic of the inputs and are reflected in the device's output. Previous approaches to transient computation have used large reservoirs of...
Article
This research investigates the potential utility of chaotic dynamics in neural information processing. A novel chaotic spiking neural network model is presented which is composed of non-linear dynamic state (NDS) neurons. The activity of each NDS neuron is driven by a set of non-linear equations coupled with a threshold based spike output mechanism...
Conference Paper
Full-text available
A novel approach to human motion recognition is proposed that is based on a variation of the Nonlinear Transient Computation Ma- chine (NTCM). The motion data used to train the NTCM comes from point-light display video sequences of a human walking. The NTCM is trained to distinguish between sequences of video frames that depict co- ordinated walkin...
Conference Paper
Full-text available
This paper proposes a novel nonlinear transient computation device described as the LTCM that uses the chaotic attractor provided by the Lorenz system of equations to perform pattern recognition. Previous work on nonlinear transient computation has demonstrated that such de- vices can process time varying input signals. This paper investigates the...
Conference Paper
Full-text available
A novel nonlinear transient computation device is presented which is designed to perform computations on multiple spike-train input signals. The input signals perturb the internal dynamic state of the device in a way that is characteristic of the input signal presented in each case. These characteristics are reflected in the output spike train of t...
Conference Paper
Full-text available
This tutorial reports on the use of nonlinear dynamics in several different models of neural systems. We discuss a number of dis- tinct approaches to neural information processing based on nonlinear dy- namics. The models we consider combine controlled chaotic models with phenomenological models of spiking mechanisms as well as using weakly chaotic...
Conference Paper
Full-text available
Article
Chaos offers several advantages to the Engineer over other non-chaotic dynamics. One is that chaotic systems are often significantly easier to control than other linear or non-linear systems, requiring only small, appropriately timed perturbations to constrain them within specific unstable periodic orbits (UPOs). Another is that chaotic attractors...
Article
Chaos offers several advantages to the Engineer over other non-chaotic dynamics. One is that chaotic systems are often significantly easier to control than other linear or non-linear systems, requiring only small, appropriately timed perturbations to constrain them within specific Unstable Periodic Orbits (UPOs). Another is that chaotic attractors...
Article
The complex dynamics that emerge from systems governed by deterministic chaos offer significant advantages to the neuromorphic engineer. Included in these is the potential for a very large memory store and the ease with which chaotic systems can be controlled. By definition, a chaotic system is a periodic. However, during the course of its trajecto...
Conference Paper
Full-text available
The non-linear dynamics of a chaotic attractor offer a number of useful features to the developer of neuromorphic systems. Included in these is the ability for efficient memory storage and recall. A chaotic attractor has a potentially infinite number of unstable periodic orbits (UPO) embedded within it. These orbits can be stabilised with the appli...
Conference Paper
Full-text available
The basic premise of this research is that deterministic chaos is a powerful mechanism for the storage and retrieval of information in the dynamics of artificial neural networks. Substantial evidence has been found in biological studies for the presence of chaos in the dynamics of natural neuronal systems [1-3]. Many have suggested that this chaos...
Article
Whilst rules extracted from neural networks assist the explanation process, in isolation they do not illustrate the relative importance of each input parameter nor how sensitive the network's output is to these parameters. In this paper we discuss three related measures of input parameter influence which can be used to support explanation facilitie...

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