THE INFLUENCE OF DEPOSITION AND PROCESSING CONDITIONS ON THE PROPERTIES OF EVAPORATED CdTe/ CdS LAYERS AND SOLAR CELLS

The influence of the deposition and CdCl₂ doping conditions on the properties of CdTe layers and on the performance of CdTe/CdS/ITO/glass solar cells is reported. Relatively high deposition temperatures (300-350°C) were found to enhance the reproducibility of the optical quality of the CdTe. Oxidation of CdTe layers during air annealing was observed and monitored by XRD. Conventional wet dip and CdCl₂ vapour doping of CdTe are compared. Methods for reducing the incidence of pinholes in the CdTe are described, the junction uniformity having been monitored by EBIC. The best solar cell made in this work had an efficiency of 9.87%. (V _oc = 0.696V, J _sc = 24.1 mA/cm², FF = 59%).     

Towards estimating computer users＇ mood from interaction behaviour with keyboard and mouse

The purpose of this exploratory research was to study the relationship between the mood of computer users and their use of keyboard and mouse to examine the possibility of creating a generic or individualized mood measure. To examine this, a field study （n = 26） and a controlled study （n = 16） were conducted. In the field study, interaction data and self-reported mood measurements were collected during normal PC use over several days. In the controlled study, participants worked on a programming task while listening to high or low arousing background music. Besides subjective mood measurement, galvanic skin response （GSR） data was also collected. Results found no generic relationship between the interaction data and the mood data. However, the re- suits of the studies found significant average correlations be- tween mood measurement and personalized regression models based on keyboard and mouse interaction data. Together the results suggest that individualized mood prediction is pos- sible from interaction behaviour with keyboard and mouse.     

Designing interfaces for explicit preference elicitation: a user-centered investigation of preference representation and elicitation process

Two problems may arise when an intelligent (recommender) system elicits users?? preferences. First, there may be a mismatch between the quantitative preference representations in most preference models and the users?? mental preference models. Giving exact numbers, e.g., such as ??I like 30?days of vacation 2.5?times better than 28?days?? is difficult for people. Second, the elicitation process can greatly influence the acquired model (e.g., people may prefer different options based on whether a choice is represented as a loss or gain). We explored these issues in three studies. In the first experiment we presented users with different preference elicitation methods and found that cognitively less demanding methods were perceived low in effort and high in liking. However, for methods enabling users to be more expressive, the perceived effort was not an indicator of how much the methods were liked. We thus hypothesized that users are willing to spend more effort if the feedback mechanism enables them to be more expressive. We examined this hypothesis in two follow-up studies. In the second experiment, we explored the trade-off between giving detailed preference feedback and effort. We found that familiarity with and opinion about an item are important factors mediating this trade-off. Additionally, affective feedback was preferred over a finer grained one-dimensional rating scale for giving additional detail. In the third study, we explored the influence of the interface on the elicitation process in a participatory set-up. People considered it helpful to be able to explore the link between their interests, preferences and the desirability of outcomes. We also confirmed that people do not want to spend additional effort in cases where it seemed unnecessary. Based on the findings, we propose four design guidelines to foster interface design of preference elicitation from a user view.     

The relationship between individual characteristics and experienced presence

People experience different levels of presence (e.g.  and ), and different levels of cybersickness (Sharples, Cobb, Moody, & Wilson, 2008) even though they are immersed in the same virtual environment setting. In the current study, we raised the question how differences in individual characteristics might relate to differences in sensed presence for a virtual environment related to public speaking. The individual characteristics included in the experiment were related to visual abilities, personality traits, cognitive styles, and demographic factors. We recruited 88 participants, who were first immersed in a non-stereoscopic neutral environment, and then in a public speaking world: once with stereoscopic rendering and once without stereoscopic rendering, in a counter-balanced order. The results showed that immersive tendency and monocular visual ability were significantly correlated with presence and these correlations were consistent among the three virtual environments. Immersive tendencies and its subscale “involvement” were also found to be significantly correlated with cybersickness in all three worlds. Screening people on these variables may help to recognize the users who are more likely to benefit from virtual reality applications and may help to reduce the number of dropouts during virtual reality exposure therapy.     

Distributed collaborative situation-map making for disaster response

A situation map that shows the overview of a disaster situation serves as a valuable tool for disaster response teams. It helps them to orientate their location and to make disaster response decisions. It is, however, a complicated task to rapidly generate a complete and comprehensive situation map of a disaster area, particularly due to the centralized organization of disaster management and the limited emergency services. In this study, we propose to let the affected population be utilized as an additional resource that can actively help to make such a situation map.The aim of this study was to investigate the possibility of constructing a shared situation map using a collaborative distributed mechanism. By examining earlier research, a detailed list of potential problems is identified in the collaborative map-making process. These problems were then addressed in an experiment which evaluated a number of proposed solutions. The results showed that more collaboration channels led to a situation map of better quality, and that including confidence information for objects and events in the map helped the discussion process during the map-making.     

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.     

Compositional Operational Semantics of a UML-Kernel-Model Language

We define a compositional operational semantics for state machines and their composition in UML. Each state machine describes the behavior of an object of a class. If a class of a newly generated object is active, a new activity group, which is a singly-threaded collection of objects, is generated. Communication of state machines between activity groups differs from the one inside an activity group. We introduce (i) two parallel combinators reflecting this difference, which return a SOS given that their arguments are SOS, (ii) an SOS for each state machine regarded in isolation.     

Making mundane pleasures visible: mediating daily likings with lightweight technology

This article discusses the sharing of daily pleasures with lightweight technology. Two mobile applications called PosiPost Me (Mobile internet edition) and PosiPost Be (Bluetooth edition) were developed to understand the potential of remote and proximity-based sharing of positive messages. These implementations are compared through an empirical study of 15 participants in England and The Netherlands who used both applications for a week each. Drawing from interviews and a corpus of 379 shared messages, the study presents an exploration of the types of pleasures people expressed in everyday use. The study addresses the influence of the two applications on the nature of the messages shared. It further points to the importance of the mundaneness of the postings and discusses the role lightweight mobile technology can play in making mundane pleasures visible.