REGAL : a regularization based algorithm for reinforcement learning in weakly communicating MDPs

We provide an algorithm that achieves the optimal regret rate in an unknown weakly communicating Markov Decision Process (MDP). The algorithm proceeds in episodes where, in each episode, it picks a policy using regularization based on the span of the optimal bias vector. For an MDP with S states and A actions whose optimal bias vector has span bounded by H, we show a regret bound of ~ O(HS p AT ). We also relate the span to various diameter-like quantities associated with the MDP, demonstrating how our results improve on previous regret bounds.

Multicultural education : the understandings of preschool teachers in Singapore

For multicultural education to be effective, it must be introduced in the early years and reinforced throughout the school years. It is important for teachers of young children to be equipped with the appropriate knowledge, skills and positive attitudes to promote multiculturalism in their classrooms. This paper reports on a survey involving preschool teachers in Singapore who were participating in an in-service training course. The teachers completed a questionnaire to indicate their understandings of multicultural education and their perceptions of its importance in early childhood education. The findings indicated that the teachers endorsed the need for multicultural education in preschools and the importance of children learning tolerance and understanding of other cultures in the Singaporean context. However, while preschool teachers held positive attitudes towards multicultural education, there was limited understanding of the challenges in implementing an anti-bias teaching and curriculum approach. The implications of these findings for preschool teacher education programs in Singapore and in other countries focus on supporting teachers in developing more critical and deeper understandings of multiculturalism.

Visceral hedonic rhetoric

Emotional responses can incite and entice consumers to select a particular product from a row of similar items and thus have a considerable impact on purchase decisions. Consequently, more and more companies are challenging designers to address the emotional impact of their work and to design for emotion and consumerproduct relationships. Furthermore, the creation of emotional attachment to one’s possessions is one way of approaching a sustainable consumer-product relationship. The aim of this research is to gain a deeper understanding of the instantaneous emotional attachment that consumers form with products and its subsequent implications for product development. The foci of the study are visceral design, consumer hedonics and product rhetoric. Studied in a conglomerate they become an area of new investigation: visceral hedonic rhetoric. In this context, the term “visceral hedonic rhetoric” is defined as the properties of a product that persuasively elicit the pursuit of pleasure at an instinctual level of cognition. This study explores visceral hedonic rhetoric evident in the design of interactive products and resides within the context of emotional design research. It employs an empirical approach to understand how consumers respond hedonically on a visceral level to rhetoric in products. Specifically, it examines visceral hedonic responses given by thirty participants to the stimuli of six mobile telephones, six Mp3 players and six USB memory flash drives. The study findings demonstrate a hierarchy of visceral hedonic rhetoric evident in interactive products. This hierarchy of visceral hedonic attributes include: colour, size, shape, intrigue, material, perceived usability, portability, perceived function, novelty, analogy, brand, quality, texture and gender. However, it is the interrelationships between these visceral hedonic attributes that are the most significant findings of this research. Certain associations were revealed between product attribute combinations and consumer perception. The most predominant of these were: gender bias associated with colour selection; the creation of intrigue through a vibrant attention-grabbing colour; perceived ease of use and function; product confidence as a result of brand familiarity and perceived usability; analogous association through familiarity with similar objects and shapes; and the association of longevity with quality, novelty or recent technology. A significant outcome of the research is the distillation of visceral hedonic rhetoric design principles, and a tool to assist designers in harnessing the full potential of visceral hedonic rhetoric. This study contributes to the identification of the emerging research field of visceral hedonic rhetoric. Application of this study’s findings has the potential to provide a hedonic consumer-product relationship that is more meaningful, less disposable and more sustainable. This theory of visceral hedonic rhetoric is not only a significant contribution to design knowledge but is also generally transferable to other research domains, as later suggested in future research avenues.

A hydrogen gas sensor based on Pt/nanostructured WO3/SiC Schottky diode

Pt/nanostructured WO3/SiC Schottky diodes were fabricated and applied for hydrogen gas sensing applications. The nanostructured WO3 films were synthesized from tungsten coated SiC substrates via an acid-etching method using a 1.5 M HNO3 solution for 1 hr, 2 hrs and 3 hrs duration. Scanning electron microscopy of the developed films revealed platelet crystals with thicknesses in the order of 20-60 nm and lengths between 100-700 nm. X-ray diffraction analysis revealed that the rate of oxidation of tungsten increases as the duration of acid-etching increases. The devices were tested towards hydrogen gas balanced in air at different temperatures from 25°C to 200°C. At 200°C, voltage shifts of 0.45 V, 0.93 V and 2.37 V were recorded for devices acid-etched for 1 hr, 2 hrs and 3 hrs duration, respectively upon exposure to 1% hydrogen, under a constant forward bias current of 500 µA.

Development of the rural statistical sustainability framework tool

It is important to promote a sustainable development approach to ensure that economic, environmental and social developments are maintained in balance. Sustainable development and its implications are not just a global concern, it also affects Australia. In particular, rural Australian communities are facing various economic, environmental and social challenges. Thus, the need for sustainable development in rural regions is becoming increasingly important. To promote sustainable development, proper frameworks along with the associated tools optimised for the specific regions, need to be developed. This will ensure that the decisions made for sustainable development are evidence based, instead of subjective opinions. To address these issues, Queensland University of Technology (QUT), through an Australian Research Council (ARC) linkage grant, has initiated research into the development of a Rural Statistical Sustainability Framework (RSSF) to aid sustainable decision making in rural Queensland. This particular branch of the research developed a decision support tool that will become the integrating component of the RSSF. This tool is developed on the web-based platform to allow easy dissemination, quick maintenance and to minimise compatibility issues. The tool is developed based on MapGuide Open Source and it follows the three-tier architecture: Client tier, Web tier and the Server tier. The developed tool is interactive and behaves similar to a familiar desktop-based application. It has the capability to handle and display vector-based spatial data and can give further visual outputs using charts and tables. The data used in this tool is obtained from the QUT research team. Overall the tool implements four tasks to help in the decision-making process. These are the Locality Classification, Trend Display, Impact Assessment and Data Entry and Update. The developed tool utilises open source and freely available software and accounts for easy extensibility and long-term sustainability.

New methodologies for researching news discussion on Twitter

Twitter has become a major instrument for the rapid dissemination and subsequent debate of news stories. It has been instrumental both in drawing attention to events as they unfolded (such as the emergency landing of a plane in New York’s Hudson River in 2009) and in facilitating a sustained discussion of major stories over timeframes measured in weeks and months (including the continuing saga around Wikileaks and Julian Assange), sometimes still keeping stories alive even if mainstream media attention has moved on elsewhere. More comprehensive methodologies for research into news discussion on Twitter – beyond anecdotal or case study approaches – are only now beginning to emerge. This paper presents a large-scale quantitative approach to studying public communication in the Australian Twittersphere, developed as part of a three-year ARC Discovery project that also examines blogs and other social media spaces. The paper will both outline the innovative research tools developed for this work, and present outcomes from an application of these methodologies to recent and present news themes. Our methodology enables us to identify major themes in Twitter’s discussion of these events, trace their development and decline over time, and map the dynamics of the discussion networks formed ad hoc around specific themes (in part with the help of Twitter #hashtags: brief identifiers which mark a tweet as taking part in an established discussion). It is also able to identify links to major news stories and other online resources, and to track their dissemination across the wider Twittersphere.

An ultraviolet selective photodetector based on a nanocrystalline TiO2 photoelectrochemical cell

Solar ultraviolet (UV) radiation causes a range of skin disorders as well as affecting vision and the immune system. It also inhibits development of plants and animals. UV radiation monitoring is used routinely in some locations in order to alert the population to harmful solar radiation levels. There is ongoing research to develop UV-selective-sensors [1–3]. A personal, inexpensive and simple UV-selective-sensor would be desirable to measure UV intensity exposure. A prototype of such a detector has been developed and evaluated in our laboratory. It comprises a sealed two-electrode photoelectrochemical cell (PEC) based on nanocrystalline TiO2. This abundant semiconducting oxide, which is innocuous and very sta-ble, is the subject of intense study at present due to its application in dye sensitized solar cells (DSSC) [4]. Since TiO2 has a wide band gap (EG = 3.0 eV for rutile and EG = 3.2 eV for anatase), it is inher-ently UV-selective, so that UV filters are not required. This further reduces the cost of the proposed photodetector in comparison with conventional silicon detectors. The PEC is a semiconductor–electrolyte device that generates a photovoltage when it is illuminated and a corresponding photocur-rent if the external circuit is closed. The device does not require external bias, and the short circuit current is generally a linear function of illumination intensity. This greatly simplifies the elec-trical circuit needed when using the PEC as a photodetector. DSSC technology, which is based on a PEC containing nanocrystalline TiO2 sensitized with a ruthenium dye, holds out the promise of solar cells that are significantly cheaper than traditional silicon solar cells. The UV-sensor proposed in this paper relies on the cre-ation of electron–hole pairs in the TiO2 by UV radiation, so that it would be even cheaper than a DSSC since no sensitizer dye is needed. Although TiO2 has been reported as a suitable material for UV sensing [3], to the best of our knowledge, the PEC configuration described in the present paper is a new approach. In the present study, a novel double-layer TiO2 structure has been investigated. Fabrication is based on a simple and inexpensive technique for nanostructured TiO2 deposition using microwave-activated chemical bath deposition (MW-CBD) that has been reported recently [5]. The highly transparent TiO2 (anatase) films obtained are densely packed, and they adhere very well to the transparent oxide (TCO) substrate [6]. These compact layers have been studied as contacting layers in double-layer TiO2 structures for DSSC since improvement of electron extraction at the TiO2–TCO interface is expected [7]. Here we compare devices incorporating a single mesoporous nanocrystalline TiO2 structure with devices based on a double structure in which a MW-CBD film is situated between the TCO and the mesoporous nanocrystalline TiO2 layer. Besides improving electron extraction, this film could also help to block recombination of electrons transferred to the TCO with oxidized species in the electrolyte, as has been reported in the case of DSSC for compact TiO2 films obtained by other deposition tech-niques [8,9]. The two types of UV-selective sensors were characterized in detail. The current voltage characteristics, spectral response, inten-sity dependence of short circuit current and response times were measured and analyzed in order to evaluate the potential of sealed mesoporous TiO2-based photoelectrochemical cells (PEC) as low cost personal UV-photodetectors.

Statistics of tricoherence

Statistics of the estimates of tricoherence are obtained analytically for nonlinear harmonic random processes with known true tricoherence. Expressions are presented for the bias, variance, and probability distributions of estimates of tricoherence as functions of the true tricoherence and the number of realizations averaged in the estimates. The expressions are applicable to arbitrary higher order coherence and arbitrary degree of interaction between modes. Theoretical results are compared with those obtained from numerical simulations of nonlinear harmonic random processes. Estimation of true values of tricoherence given observed values is also discussed