Self-Supervised Vision-Based Detection of the Active Speaker as Support for Socially-Aware Language Acquisition

This paper presents a self-supervised method for visual detection of the active speaker in a multi-person spoken interaction scenario. Active speaker detection is a fundamental prerequisite for any artificial cognitive system attempting to acquire language in social settings. The proposed method is intended to complement the acoustic detection of the active speaker, thus improving the system robustness in noisy conditions. The method can detect an arbitrary number of possibly overlapping active speakers based exclusively on visual information about their face. Furthermore, the method does not rely on external annotations, thus complying with cognitive development. Instead, the method uses information from the auditory modality to support learning in the visual domain. This paper reports an extensive evaluation of the proposed method using a large multi-person face-to-face interaction dataset. The results show good performance in a speaker dependent setting. However, in a speaker independent setting the proposed method yields a significantly lower performance. We believe that the proposed method represents an essential component of any artificial cognitive system or robotic platform engaging in social interactions.Comment: 10 pages, IEEE Transactions on Cognitive and Developmental System

Outcome of preoperative radiotherapy in the treatment of cervical cancer with focus on protein expression and dosimetry

Treatment with preoperative intracavitary radiotherapy (ICRT) is used in cervical cancer with the intention to reduce the tumour burden and sterilize microscopic disease in the paracervical tissues. Preoperative ICRT is, however, a controversial treatment regime since it is unclear if addition of ICRT to surgery improves treatment outcome compared to surgery alone. This question constitutes the basis of this thesis. In relation to this issue we have studied clinical, dosimetric and molecular key factors with focus on DNA damage repair signalling molecules of possible importance for radiotherapy sensitivity. One possible way to investigate the potential benefit of preoperative ICRT is to analyze whether complete tumour remission in the surgical specimen after preoperative ICRT is correlated to treatment outcome or not. In paper I we analyzed treatment results after preoperative ICRT in patients with cervical cancer stage IB-IIA. We found a strong correlation between pathologic complete remission (pCR) and survival with a 5-year survival of 95% in patients with pCR compared to 46% in patients with residual tumour (non-pCR) (p<0.0001). These results indicate that the use of preoperative ICRT may contribute to treatment outcome compared to surgery alone. DNA double strand breaks (DNA DSBs) and their repair has in tumour cell lines been linked to radiosensitivity. In paper II we therefore analyzed the expression of proteins related to the DNA-PK repair pathway; DNA-PKcs, Ku70, Ku86, p53, p21 and Mdm-2 in pre-treatment tumour tissue with the aim to find predictive markers for radiotherapy response. Our hypothesis was that high DNA repair capacity in the primary tumour, reflected by a high frequency of cells positive for DNA-PK proteins, would correlate with non-pCR cases. However, we did not find that any of the analyzed proteins were predictive for radiotherapy response. Our hypothesis in paper III was that residual tumours that survived radiotherapy would display a higher frequency of DNA-PK positive cells reflecting a higher capacity to DNA DSB repair compared to their corresponding primary tumours. The expression of DNA-PKcs, Ku70, Ku86, p53, p21 and Mdm-2 proteins was compared in pre- and post-treatment tumour tissue. We found that residual tumours showed an increased frequency of tumour cells positive for DNA-PK complex proteins compared to the frequency in the primary tumour. This result may be interpreted as that radiation causes a selection pressure allowing tumour cells with high DNA-PK expression to survive RT. Biological effective dose (BED) can be used to predict the influence on outcome of different treatment schedules for individual patients. In paper IV we evaluated BED with respect to survival, local control and late toxicity in patients treated either with radiotherapy and surgery or with radiotherapy alone. We found a correlation between BED and treatment outcome for patients treated with radiotherapy alone but not for patients treated with radiotherapy and surgery. No correlations were found between BED and late toxicity from bladder and rectum. In conclusion this thesis illustrates that treatment with preoperative intracavitary radiotherapy may be beneficial for patients with cervical cancer stage IB-IIA. We found that the expression of the DNA-PK complex proteins in primary tumour cannot predict RT response. We did, however, find that the frequency of the DNA-PK complex proteins is higher in residual tumour after ICRT than in corresponding primary tumour. BED cannot be used as a predictive factor for the outcome in patients treated with pre-and postoperative radiotherapy or for the late side effects but does correlate with local control of the tumour and survival in patients treated with RT alone

General equation for Zeno-like effects in spontaneous exponential decay

It was shown that different mechanisms of perturbation of spontaneous decay constant: inelastic interaction of emitted particles with particle detector, decay onto an unstable level, Rabi transition from the final state of decay (electromagnetic field domination) and some others are really the special kinds of one general effect - perturbation of decay constant by dissipation of the final state of decay. Such phenomena are considered to be Zeno-like effects and general formula for perturbed decay constant is deduced.Comment: LaTeX 2.09 file, 11 pages, no figures. Accepted in Physics Letters

Reverse Engineering Psychologically Valid Facial Expressions of Emotion into Social Robots

Social robots are now part of human society, destined for schools, hospitals, and homes to perform a variety of tasks. To engage their human users, social robots must be equipped with the essential social skill of facial expression communication. Yet, even state-of-the-art social robots are limited in this ability because they often rely on a restricted set of facial expressions derived from theory with well-known limitations such as lacking naturalistic dynamics. With no agreed methodology to objectively engineer a broader variance of more psychologically impactful facial expressions into the social robots' repertoire, human-robot interactions remain restricted. Here, we address this generic challenge with new methodologies that can reverse-engineer dynamic facial expressions into a social robot head. Our data-driven, user-centered approach, which combines human perception with psychophysical methods, produced highly recognizable and human-like dynamic facial expressions of the six classic emotions that generally outperformed state-of-art social robot facial expressions. Our data demonstrates the feasibility of our method applied to social robotics and highlights the benefits of using a data-driven approach that puts human users as central to deriving facial expressions for social robots. We also discuss future work to reverse-engineer a wider range of socially relevant facial expressions including conversational messages (e.g., interest, confusion) and personality traits (e.g., trustworthiness, attractiveness). Together, our results highlight the key role that psychology must continue to play in the design of social robots

Purification through Zeno-like Measurements

A series of frequent measurements on a quantum system (Zeno-like measurements) is shown to result in the ``purification'' of another quantum system in interaction with the former. Even though the measurements are performed on the former system, their effect drives the latter into a pure state, irrespectively of its initial (mixed) state, provided certain conditions are satisfied.Comment: REVTeX4, 4 pages, 1 figure; to be published in Phys. Rev. Lett. (2003

User Evaluation of the SYNFACE Talking Head Telephone

Abstract. The talking-head telephone, Synface, is a lip-reading support for people with hearing-impairment. It has been tested by 49 users with varying degrees of hearing-impaired in UK and Sweden in lab and home environments. Synface was found to give support to the users, especially in perceiving numbers and addresses and an enjoyable way to communicate. A majority deemed Synface to be a useful product.

Stability and instability in parametric resonance and quantum Zeno effect

A quantum mechanical version of a classical inverted pendulum is analyzed. The stabilization of the classical motion is reflected in the bounded evolution of the quantum mechanical operators in the Heisenberg picture. Interesting links with the quantum Zeno effect are discussed.Comment: 6 pages, 3 figure

The decay law can have an irregular character

Within a well-known decay model describing a particle confined initially within a spherical $\delta$ potential shell, we consider the situation when the undecayed state has an unusual energy distribution decaying slowly as $k\to\infty$; the simplest example corresponds to a wave function constant within the shell. We show that the non-decay probability as a function of time behaves then in a highly irregular, most likely fractal way.Comment: 4 pages, 3 eps figure

Sufficient conditions for the anti-Zeno effect

The ideal anti-Zeno effect means that a perpetual observation leads to an immediate disappearance of the unstable system. We present a straightforward way to derive sufficient conditions under which such a situation occurs expressed in terms of the decaying states and spectral properties of the Hamiltonian. They show, in particular, that the gap between Zeno and anti-Zeno effects is in fact very narrow.Comment: LatEx2e, 9 pages; a revised text, to appear in J. Phys. A: Math. Ge

Valoração ecológica aplicada a áreas de preservação permanente.

Este trabalho aplica os conceitos da Avaliação Emergética e da Avaliação Funcional dos Ecossistemas para estimar os valores associados à manutenção de Áreas de Preservação Permanente diante de uma perspectiva ecológica; as áreas de estudo estão conservadas em pequenas propriedades rurais no interior do Estado de São Paulo, Brasil. Foram valorados seis Serviços Ambientais: (1) o Serviço de fornecimento de água e nutrientes para os riachos; (2) o Serviço de recarga de aqüíferos; (3) o Serviço de regulação do clima; (4) o Serviço de fornecimento de alimento para a fauna e flora silvestre dos ecossistemas vizinhos; (5) o Serviço de polinização, controle biológico, aumento da fertilidade e da produtividade do sistema; (6) o Serviço fixação de carbono e regulação da composição química da atmosfera. Os valores totais dos serviços anuais, para os fragmentos de 7, 25, 75 e 200 anos respectivamente, somam R$3.376,13, R$ 3.534,86, R$4.015,95 e R$ 4.712,06. As Áreas de Preservação Permanente são importantes para sustentabilidade de processos produtivos que usufruem, diretamente, dos diferentes Serviços Ambientais prestados por estas áreas e para a manutenção do bem estar das populações humanas