2,009 research outputs found
Understanding changes in teacher beliefs and identity formation: A case study of three novice teachers in Hong Kong
Novice teachers often undergo an identity shift from learner to teacher. Along this process, their instructional beliefs change considerably which in turn affect their teacher identity formation. Drawing on
data collected mainly through interviews with three novice English teachers formore than one year, the present study examines their firstyear teaching experience in Hong Kong secondary schools, focusing
on changes of their English teaching beliefs and the impact of these changes on their identity construction. Findings reveal that while the teachersâ initial teaching beliefs were largely shaped in their prior school learning and learning-to-teach experience, these beliefs changed and were reshaped a great deal when encountering various contextual realities, and these changes further influenced their views on their teacher identity establishment, unfortunately in a more negative
than positive direction. The study sheds light on the importance of institutional support in affording opportunities for novice teachersâ workplace learning and professional development
Tuning the optoelectronic properties of emerging solar absorbers through cation disorder engineering
Chalcogenide solar absorbers, such as AgBiS2 and kesterites, have gained a resurgence of interest recently, owing to their high stability compared to metalâhalide compounds, as well as their rising efficiencies in photovoltaic devices. Although their optical and electronic properties are conventionally tuned through the composition and structure, cation disorder has increased in prominence as another important parameter that influences these properties. In this minireview, we define cation disorder as the occupation of a cation crystallographic site with different species, and the homogeneity of this cation disorder as how regular the alternation of species in this site is. We show that cation disorder is not necessarily detrimental, and can lead to increases in absorption coefficient and reductions in bandgap, enabling the development of ultrathin solar absorbers for lightweight photovoltaics. Focusing on kesterites and ABZ2 materials (where A = monovalent cation, B = divalent cation, and Z is a chalcogenide anion), we discuss how the degree and homogeneity of cation disorder influences the optical properties, charge-carrier transport and photovoltaic performance of these materials, as well as how cation disorder could be tuned and quantified. We finish with our perspectives on the important questions moving forward in making use of cation disorder engineering as a route to achieve more efficient solar absorbers
k-Same-Siamese-GAN: k-Same Algorithm with Generative Adversarial Network for Facial Image De-identification with Hyperparameter Tuning and Mixed Precision Training
For a data holder, such as a hospital or a government entity, who has a
privately held collection of personal data, in which the revealing and/or
processing of the personal identifiable data is restricted and prohibited by
law. Then, "how can we ensure the data holder does conceal the identity of each
individual in the imagery of personal data while still preserving certain
useful aspects of the data after de-identification?" becomes a challenge issue.
In this work, we propose an approach towards high-resolution facial image
de-identification, called k-Same-Siamese-GAN, which leverages the
k-Same-Anonymity mechanism, the Generative Adversarial Network, and the
hyperparameter tuning methods. Moreover, to speed up model training and reduce
memory consumption, the mixed precision training technique is also applied to
make kSS-GAN provide guarantees regarding privacy protection on close-form
identities and be trained much more efficiently as well. Finally, to validate
its applicability, the proposed work has been applied to actual datasets - RafD
and CelebA for performance testing. Besides protecting privacy of
high-resolution facial images, the proposed system is also justified for its
ability in automating parameter tuning and breaking through the limitation of
the number of adjustable parameters
Give me a hint: An ID-free small data transmission protocol for dense IoT devices
IoT (Internet of Things) has attracted a lot of attention recently. IoT devices need to report their data or status to base stations at various frequencies. The IoT communications observed by a base station normally exhibit the following characteristics: (1) massively connected, (2) lightly loaded per packet, and (3) periodical or at least mostly predictable. The current design principals of communication networks, when applied to IoT scenarios, however, do not fit well to these requirements. For example, an IPv6 address is 128 bits, which is much longer than a 16-bit temperature report. Also, contending to send a small packet is not cost-effective. In this work, we propose a novel framework, which is slot-based, schedule-oriented, and identity-free for uploading IoT devices' data. We show that it fits very well for IoT applications. The main idea is to bundle time slots with certain hashing functions of device IDs, thus significantly reducing transmission overheads, including device IDs and contention overheads. The framework is applicable from small-scale body-area (wearable) networks to large-scale massively connected IoT networks. Our simulation results verify that this framework is very effective for IoT small data uploading
r-Hint: A message-efficient random access response for mMTC in 5G networks
Massive Machine Type Communication (mMTC) has attracted increasing attention due to the explosive growth of IoT devices. Random Access (RA) for a large number of mMTC devices is especially difficult since the high signaling overhead between User Equipments (UEs) and an eNB may overwhelm the available spectrum resources. To address this issue, we propose ârespond by hintâ (r-Hint), an ID-free handshaking protocol for contention-based RA in mMTC. The core idea of r-Hint is to avoid sequentially notifying contending UEs of their IDs by broadcasting a hint in the RA Response (RAR). To do so, we exploit the concept of prime factorization and hashing to encode the hint such that UEs can extract their required information accordingly. Our simulation results show that r-Hint reduces the RAR message size by 20%â40%. Such reduction can be translated to around 50% improvement of spectrum efficiency in LTE-M
Multi-Metric AutoRec for High Dimensional and Sparse User Behavior Data Prediction
User behavior data produced during interaction with massive items in the
significant data era are generally heterogeneous and sparse, leaving the
recommender system (RS) a large diversity of underlying patterns to excavate.
Deep neural network-based models have reached the state-of-the-art benchmark of
the RS owing to their fitting capabilities. However, prior works mainly focus
on designing an intricate architecture with fixed loss function and regulation.
These single-metric models provide limited performance when facing
heterogeneous and sparse user behavior data. Motivated by this finding, we
propose a multi-metric AutoRec (MMA) based on the representative AutoRec. The
idea of the proposed MMA is mainly two-fold: 1) apply different -norm on
loss function and regularization to form different variant models in different
metric spaces, and 2) aggregate these variant models. Thus, the proposed MMA
enjoys the multi-metric orientation from a set of dispersed metric spaces,
achieving a comprehensive representation of user data. Theoretical studies
proved that the proposed MMA could attain performance improvement. The
extensive experiment on five real-world datasets proves that MMA can outperform
seven other state-of-the-art models in predicting unobserved user behavior
data.Comment: 6 pages, 4 Table
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