Detecting emotional state of a child in a conversational computer game

The automatic recognition of user’s communicative style within a spoken dialog system framework, including the affective aspects, has received increased attention in the past few years. For dialog systems, it is important to know not only what was said but also how something was communicated, so that the system can engage the user in a richer and more natural interaction. This paper addresses the problem of automatically detecting “frustration”, “politeness”, and “neutral” attitudes from a child’s speech communication cues, elicited in spontaneous dialog interactions with computer characters. Several information sources such as acoustic, lexical, and contextual features, as well as, their combinations are used for this purpose. The study is based on a Wizard-of-Oz dialog corpus of 103 children, 7–14 years of age, playing a voice activated computer game. Three-way classification experiments, as well as, pairwise classification between polite vs. others and frustrated vs. others were performed. Experimental results show that lexical information has more discriminative power than acoustic and contextual cues for detection of politeness, whereas context and acoustic features perform best for frustration detection. Furthermore, the fusion of acoustic, lexical and contextual information provided significantly better classification results. Results also showed that classification performance varies with age and gender. Specifically, for the “politeness” detection task, higher classification accuracy was achieved for females and 10–11 years-olds, compared to males and other age groups, respectively.     

Controlled invariance of ellipsoids: linear vs. nonlinear feedback

Several equivalent conditions or statements for set invariance were obtained for systems with one saturating actuator in a recent paper. In particular, it was shown that the existence of a nonlinear feedback that makes an ellipsoid invariant is equivalent to the existence of a feedback linear inside the ellipsoid that makes it invariant. In this paper, we will show that this equivalence property holds conditionally for systems with multiple saturating actuators. We will provide a criterion to check if the largest ellipsoid made invariant by nonlinear feedback can also be made invariant by a feedback linear inside the ellipsoid. Numerical examples reveal that this criterion is usually satisfied. The equivalence of other set invariance conditions will also be investigated.     

The effects of speech–gesture cooperation in animated agents’ behavior in multimedia presentations

Until now, research on arrangement of verbal and non-verbal information in multimedia presentations has not considered multimodal behavior of animated agents. In this paper, we will present an experiment exploring the effects of different types of speech–gesture cooperation in agents’ behavior: redundancy (gestures duplicate pieces of information conveyed by speech), complementarity (distribution of information across speech and gestures) and a control condition in which gesture does not convey semantic information. Using a Latin-square design, these strategies were attributed to agents of different appearances to present different objects. Fifty-four male and 54 female users attended three short presentations performed by the agents, recalled the content of presentations and evaluated both the presentations and the agents. Although speech–gesture cooperation was not consciously perceived, it proved to influence users’ recall performance and subjective evaluations: redundancy increased verbal information recall, ratings of the quality of explanation, and expressiveness of agents. Redundancy also resulted in higher likeability scores for the agents and a more positive perception of their personality. Users’ gender had no influence on this set of results.     

The TRAINS project: a case study in building a conversational planning agent

Abstract

The TRAINS project is an effort to build a conversationally proficient planning assistant. A key part of the project is the construction of the TRAINS system, which provides the research platform for a wide range of issues in natural language understanding, mixed-initiative planning systems, and representing and reasoning about time, actions and events. Four years have now passed since the beginning of the project. Each year a demonstration system has been produced that focused on a dialogue that illustrates particular aspects of the research. The commitment to building complete integrated systems is a significant overhead on the research, but it is considered essential to guarantee that the results constitute real progress in the field. This paper describes the goals of the project, and the experience with the effort so far.     

Linguistically-tailored video feedback increases total and positive emotional expression in a structured writing task

A strength of computer-based interventions is the capacity to tailor to individual differences, but most studies have tailored to self-report, rather than linguistic, data. The purpose of the present study was to develop and evaluate the effects of linguistically-tailored feedback on an Internet-based expressive writing intervention. Two hundred eighty-one participants were asked to engage in 3 days of expressive writing and were randomly assigned to one of 3 feedback conditions: control (no feedback), simple (feedback about levels of emotional expression), and directive (simple feedback + suggestions for emotional processing). A Perl-based implementation of Linguistic Inquiry and Word Count (LIWC) was developed in order to provide dynamic feedback to participants based on levels of emotional expression identified in their writing. This implementation provided near-perfect correlations with standard LIWC output, r’s = .98-1.00. Positive and total, but not negative, emotional expression increased over time for those who received simple or directive feedback. These findings suggest that linguistically-tailored feedback has the potential to alter patterns of engagement in computer-based interventions. However, additional research is needed to identify the most effective types of feedback in order to enhance immediate effects on writing and longitudinal effects on relevant outcomes.     

The effects of simulating human conversational style in a computer-based interview

A computer interview involves a program asking questions of the user, who responds by providing answers directly to the computer. Using a computer interview has been shown to be an effective method of eliciting information, and particularly personal information which many people find difficult to discuss face to face. While the simulation of some of the characteristics of human–human communication seems to enhance the dialogue, it appears to be the absence of others, such as being non-judgmental, unshockable, completely consistent, and unendingly patient, that gives computer interviewing its particular effectiveness.

The work reported in this paper investigated the effect of simulating in a computer interview two techniques which good human interviewers use: empathy and grouping questions. Thirty nine interviewees answered 40 questions on a computer, in combinations of human-like or computer-like question styles, and presented in either a logical or a random order.

They found the use of the human interviewer technique in the wording of questions made the computer interviews more interesting and enjoyable, than when blunt, direct questioning was used, and they answered honestly more often to the human-like style.

This investigation has shown that a computer interview can be made more effective by simulating the human interviewer technique of empathising with interviewees and softening those questions which are of a sensitive nature. It seems therefore that it is the combination of the right non-human characteristics with the right human characteristics that can produce a successful computer interview. The question for further research is which are the right characteristics in each case, given the purpose of the interview.     

Designing motivational agents: The role of praise, social comparison, and embodiment in computer feedback

The present study draws on theories of attribution, social comparison, and social facilitation to investigate how computers might use principles of motivation and persuasion to provide user feedback. In an online experiment, 192 participants performed a speed-reading task. The independent variables included whether or not the verbal feedback from the computer involved praise, whether the objective feedback showed that the participants were performing better or worse from their peers, and whether or not the feedback was presented by an on-screen agent. The main dependent variables included a subjective measure of participants’ intrinsic motivation and an objective measure of their task persistence. Results showed that providing participants with praise or comparative information on others’ performance improved intrinsic motivation. When praised, participants whose performances were comparatively low persisted in the task longer than those whose performances were comparatively high did. Additionally, the mere presence of an embodied agent on the screen increased participants’ motivation. Together, these results indicate that praise and social comparison can serve as effective forms of motivational feedback and that humanlike embodiment further improves user motivation.     

Forwarders vs. centralized server: an evaluation of two approaches for locating mobile agents

This paper evaluates and compares the performance of two approaches for locating an agent in a mobile agent environment. The first approach dynamically creates a chain of forwarders to locate a moving agent, whereas the second one relies on a centralized server to perform this task. Based on a Markov chain analysis, we compute the performance of each scheme (time to reach an agent, number of forwarders) and compare them first with simulations and second with experimental results obtained by using ProActive, a Java library. Depending on the system parameters we identify the best scheme and observe that over a LAN the server yields the best performance, whereas the forwarders yield the best performance over a MAN.     

CBR for the management and reuse of image-processing expertise: a conversational system

The development of an image-processing (IP) application is a complex activity, which can be greatly alleviated by user-friendly graphical programming environments. The major objective of the work described in this paper is to help IP experts reuse parts of their applications. A first step towards knowledge reuse has been to propose a suitable representation of the strategies of IP experts by means of IP plans (trees of tasks, methods and tools). This paper describes the CBR module of an interactive system for the development of IP plans. After a brief presentation of the overall architecture of the system and its other modules, the authors explain the distinction between an IP case and an IP plan, and give the selection criteria and functions that are used for similarity calculation. The core of the CBR module is a search/adaptation algorithm, whose main steps are detailed: retrieval of suitable cases, recursive adaptation of the selected one and memorization of new cases. The system’s implementation is presently completed; its functioning is described in a session showing the kind of assistance provided by the CBR module during the development of a new IP application.     

Signal recognition: Both components of the short time Fourier transform vs. power spectral density

A new feature representation approach was generalised and used for Gaussian recognition. The generalised approach consists of simultaneously using two new recognition features — real and imaginary Fourier components —taking into account the covariance between features. Generalisation of the approach improves recognition effectiveness. An advanced time-frequency technique, the short time Fourier transform, was considered. Covariance and the correlation coefficient between the proposed features were obtained for the first time for arbitrary stationary signals. The recognition effectiveness between the generalised approach and power spectral density was compared. It was shown that power spectral density is not an optimal feature, and represents only a particular case of the generalised approach. The use of power spectral density is optimal if simultaneously the correlation coefficient between Fourier components is equal to zero, and the standard deviations of components are equal. Use of the generalised approach provides an increase in effectiveness in comparison with power spectral density.     

Narrowing power vs efficiency in synchronous set agreement: Relationship, algorithms and lower bound

The k-set agreement problem is a generalization of the uniform consensus problem: each process proposes a value, and each non-faulty process has to decide a value such that a decided value is a proposed value, and at most k different values are decided. It has been shown that any algorithm that solves the k-set agreement problem in synchronous systems that can suffer up to t crash failures requires rounds in the worst case. It has also been shown that it is possible to design early deciding algorithms where no process decides and halts after rounds, where f is the number of actual crashes in a run (0≤f≤t).This paper explores a new direction to solve the k-set agreement problem in a synchronous system. It considers that the system is enriched with base objects (denoted has [m,?]_SA objects) that allow solving the ?-set agreement problem in a set of m processes (m<n). The paper makes several contributions. It first proposes a synchronous k-set agreement algorithm that benefits from such underlying base objects. This algorithm requires rounds, more precisely, rounds, where . The paper then shows that this bound, that involves all the parameters that characterize both the problem (k) and its environment (t, m and ?), is a lower bound. The proof of this lower bound sheds additional light on the deep connection between synchronous efficiency and asynchronous computability. Finally, the paper extends its investigation to the early deciding case. It presents a k-set agreement algorithm that directs the processes to decide and stop by round . These bounds generalize the bounds previously established for solving the k-set agreement problem in pure synchronous systems.     

HT-7低杂波电源反馈控制系统的设计与实现

介绍了在HT-7托卡马克装置中低混杂波电流驱动(LHCD)的高压源反馈控制系统.该系统通过PLC与PC并行处理的方式,对等离子体参数进行反馈控制,很好地实现了延长等离子体电流持续时间的目的,同时又有效地保证了高压源与LHCD系统的运行安全.本文给出了反馈控制系统的控制方法、软硬件的实现以及运行情况.     

HT-7低杂波电源反馈控制系统的设计与实现

介绍了在HT-7托卡马克装置中低混杂波电流驱动(LHCD)的高压源反馈控制系统。该系统通过PLC与PC并行处理的方式,对等离子体参数进行反馈控制,很好地实现了延长等离子体电流持续时间的目的,同时又有效地保证了高压源与LHCD系统的运行安全。本文给出了反馈控制系统的控制方法、软硬件的实现以及运行情况。     

MPPT算法与输入输出反馈线性化控制技术在光伏发电系统中的应用

针对目前光伏发电系统采用的固定电压法、增量电导法等最大功率点跟踪控制技术跟踪速度慢、精度不佳的问题,提出采用变步长电导增量法进行最大功率点跟踪控制;为了控制光伏系统中电网电流和直流母线电压,采用输入输出反馈线性化控制技术,使得系统的功率因数和直流母线电压可用相同的算法进行控制。在Matlab/Simulink环境下对基于变步长电导增量法算法与输入输出反馈线性化控制技术的光伏发电系统进行了建模仿真,结果表明,采用反馈线性化技术控制逆变器后,日照强度和温度变化不会对电网功率因数产生影响;变步长电导增量法提高了光伏发电系统的动态和稳态性能,且降低了电网电流的总谐波失真率。     

The design and testing of a force feedback dental simulator

The Iowa Dental Surgical Simulator is a haptic simulator to train dental students in the haptic skills of dentistry. The initial design emphasizes the detection of carious lesions. This work describes the software and implementation of the prototype system, the design tradeoffs' and the technical issues associated with haptic and graphics subsystems. The work also describes the current system performance, including a formal evaluation by practicing dentists and performance measures. A discussion of the limitations of the current system is followed by an analysis of opportunities to improve the quality of the simulator. The results should be of interest to designers of medical haptic simulation systems and other simulation designers.     

The puzzle of experience vs. memory: Peak-end theory and strategic gamification design in M-commerce

As businesses increasingly use gamified mobile marketing campaign (GMMC) systems to engage mobile shoppers, gamification in m-commerce systems warrants more attention in both IS research and design practices. Inspired by peak-end theory, this study focused on the puzzling differences between user experience vs. memory and empirically examined the impact of different experience orders of cognitive load on user perceptions and behavioral intentions. Overall, the outcomes of this research suggest that appropriate applications of the peak-end effect, moderated via users’ regulatory focus styles, can alleviate the negative mental utility imagery of users, reducing their perceived uncertainties and opt-out intentions from the GMMC. Important implications for research and practice are then discussed.     

Human perception of a conversational virtual human: an empirical study on the effect of emotion and culture

Virtual reality applications with virtual humans, such as virtual reality exposure therapy, health coaches and negotiation simulators, are developed for different contexts and usually for users from different countries. The emphasis on a virtual human’s emotional expression depends on the application; some virtual reality applications need an emotional expression of the virtual human during the speaking phase, some during the listening phase and some during both speaking and listening phases. Although studies have investigated how humans perceive a virtual human’s emotion during each phase separately, few studies carried out a parallel comparison between the two phases. This study aims to fill this gap, and on top of that, includes an investigation of the cultural interpretation of the virtual human’s emotion, especially with respect to the emotion’s valence. The experiment was conducted with both Chinese and non-Chinese participants. These participants were asked to rate the valence of seven different emotional expressions (ranging from negative to neutral to positive during speaking and listening) of a Chinese virtual lady. The results showed that there was a high correlation in valence rating between both groups of participants, which indicated that the valence of the emotional expressions was as easily recognized by people from a different cultural background as the virtual human. In addition, participants tended to perceive the virtual human’s expressed valence as more intense in the speaking phase than in the listening phase. The additional vocal emotional expression in the speaking phase is put forward as a likely cause for this phenomenon.     

The analysis of embodied communicative feedback in multimodal corpora: a prerequisite for behavior simulation

Communicative feedback refers to unobtrusive (usually short) vocal or bodily expressions whereby a recipient of information can inform a contributor of information about whether he/she is able and willing to communicate, perceive the information, and understand the information. This paper provides a theory for embodied communicative feedback, describing the different dimensions and features involved. It also provides a corpus analysis part, describing a first data coding and analysis method geared to find the features postulated by the theory. The corpus analysis part describes different methods and statistical procedures and discusses their applicability and the possible insights gained with these methods.