14 research outputs found

    Profile transformation in mobile technology based educational systems : a thesis presented in partial fulfillment of the requirements for the degree of Master of Information Science in Information Systems at Massey University, Palmerston North, New Zealand

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    In order to meet the learning needs from various types of students, computer aided education systems try to include new methods to provide personalized education to every student. From the early 1970s, a lot of adaptive educational systems have been created to provide training on a variety of subjects. Combined with the Internet, the adaptive educational systems have become web-based and even more popular. Recently, the development of mobile technology has made the web-based adaptive educational systems accessible through mobile phones. It is necessary that the students can also receive adaptive educational contents on mobile phones. This research project investigated the possible student's preference differences between Personal Computer (PC) and mobile phone, and then proposed a student profile transformation framework to address such differences. This research project conducted two surveys on the student profile transformation between PC and mobile phone. A demo web-based educational system that could be accessed from both PC and mobile phone was also developed for participants of the surveys to give more real and precise responses. Based on Felder-Silverman Learning Style Theory (Felder, 1993; Felder & Silverman, 1988) and the results of the surveys, this thesis proposes a student profile template and a student profile transformation framework, which both fully considered the influences of device capabilities and locations on students' preferences on mobile phones. Furthermore, the proposed framework integrates a solution for unsupported preferences and preference conflicts. By implementing the proposed template and framework, the students' preference changes between PC and mobile phone are automatically updated according to various device capabilities and locations, and then the students can receive adaptive educational contents that meet their updated preferences

    Integrating Low-Cost Earth-Abundant Co-Catalysts with Encapsulated Perovskite Solar Cells for Efficient and Stable Overall Solar Water Splitting

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    Metal halide perovskite solar cells have an appropriate bandgap (1.5–1.6 eV), and thus output voltage (>1 V), to directly drive solar water splitting. Despite significant progress, their moisture sensitivity still hampers their application for integrated monolithic devices. Furthermore, the prevalence of the use of noble metals as co-catalysts for existing perovskite-based devices undermines their use for low-cost H2 production. Here, a monolithic architecture for stable perovskite-based devices with earth-abundant co-catalysts is reported, demonstrating an unassisted overall solar-to-hydrogen efficiency of 8.54%. The device layout consists of two monolithically encapsulated perovskite (FA0.80MA0.15Cs0.05PbI2.55Br0.45) solar cells with low-cost earth-abundant CoP and FeNi(OH)x co-catalysts as the photocathode and photoanode, respectively. The CoP-based photocathode demonstrates more than 17 h of continuous operation, with a photocurrent density of 12.4 mA cm−2 at 0 V and an onset potential as positive as ≈1 V versus reversible hydrogen electrode (RHE). The FeNi(OH)x-based photoanode achieves a photocurrent of 11 mA cm−2 at 1.23 V versus RHE for more than 13 h continuous operation. These excellent stability and performance demonstrate the potential for monolithic integration of perovskite solar cells and low-cost earth-abundant co-catalysts for efficient direct solar H2 production.</p

    Water-Free, Conductive Hole Transport Layer for Reproducible Perovskite–Perovskite Tandems with Record Fill Factor

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    State-of-the-art perovskite–perovskite tandem solar cells incorporate a water-based poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) hole transport layer in its low bandgap subcell. However, there is a limitation regarding its use due to the moisture sensitivity of perovskites and the insulating property of PSS. Here, we overcome the limitation by using a water-free and PSS-free PEDOT-based hole transport layer for low bandgap single-junction perovskite solar cells and in perovskite–perovskite tandems. The champion tandem cell produces an efficiency of 21.5% and a fill factor of 85.8%, the highest for any perovskite-based double-junction tandems. Results of photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and conductive atomic force microscopy reveal evidence of enhanced conductivity of water-free and PSS-free PEDOT compared to its conventional counterpart. The use of water-free and PSS-free PEDOT also eliminates decomposition of high bandgap subcell with its interfacing layer stack in a tandem that otherwise occurs with conventional PEDOT:PSS. This leads to enhanced reproducibility of perovskite–perovskite tandems

    A programmable qudit-based quantum processor

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    Controlling and programming quantum devices to process quantum information by the unit of quantum dit, i.e., qudit, provides the possibilities for noise-resilient quantum communications, delicate quantum molecular simulations, and efficient quantum computations, showing great potential to enhance the capabilities of qubit-based quantum technologies. Here, we report a programmable qudit-based quantum processor in silicon-photonic integrated circuits and demonstrate its enhancement of quantum computational parallelism. The processor monolithically integrates all the key functionalities and capabilities of initialisation, manipulation, and measurement of the two quantum quart (ququart) states and multi-value quantum-controlled logic gates with high-level fidelities. By reprogramming the configuration of the processor, we implemented the most basic quantum Fourier transform algorithms, all in quaternary, to benchmark the enhancement of quantum parallelism using qudits, which include generalised Deutsch-Jozsa and Bernstein-Vazirani algorithms, quaternary phase estimation and fast factorization algorithms. The monolithic integration and high programmability have allowed the implementations of more than one million high-fidelity preparations, operations and projections of qudit states in the processor. Our work shows an integrated photonic quantum technology for qudit-based quantum computing with enhanced capacity, accuracy, and efficiency, which could lead to the acceleration of building a large-scale quantum computer
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