Algorithm and Architecture for Path Metric Aided Bit-Flipping Decoding of Polar Codes

Polar codes attract more and more attention of researchers in recent years, since its capacity achieving property. However, their error-correction performance under successive cancellation (SC) decoding is inferior to other modern channel codes at short or moderate blocklengths. SC-Flip (SCF) decoding algorithm shows higher performance than SC decoding by identifying possibly erroneous decisions made in initial SC decoding and flipping them in the sequential decoding attempts. However, it performs not well when there are more than one erroneous decisions in a codeword. In this paper, we propose a path metric aided bit-flipping decoding algorithm to identify and correct more errors efficiently. In this algorithm, the bit-flipping list is generated based on both log likelihood ratio (LLR) based path metric and bit-flipping metric. The path metric is used to verify the effectiveness of bit-flipping. In order to reduce the decoding latency and computational complexity, its corresponding pipeline architecture is designed. By applying these decoding algorithms and pipeline architecture, an improvement on error-correction performance can be got up to 0.25dB compared with SCF decoding at the frame error rate of $10^{-4}$, with low average decoding latency.Comment: 6 pages, 6 figures, IEEE Wireless Communications and Networking Conference (2019 WCNC

The new and the familiar in digital business discourse

This edited volume consists of the editor's introduction and 12 individual chapters. The chapters are grouped into three parts: new technologies and new modes of communication which are discussed in Chapters 1 to 4; new conventions associated with the new modes of communication discussed in Chapters 5 to 8; and theoretical and methodological approaches to digital business discourse in Chapters 9 to 12. The content of the chapters will be reviewed next and followed by comments on the book and some concepts in it

Australian universities engaging international students during the COVID-19 pandemic: A study of multimodal public communications with students.

Amidst the ongoing COVID-19 pandemic, university public communication channels have become unprecedentedly crucial in higher education settings. It is useful to consider how they have been used by universities as platforms for engaging international students. We collected data from three Australian universities: The University of Sydney, Curtin University and the University of New England. This data included COVID-19 information webpages, international student webpages, news/events webpages, and/or vice chancellor's video and text messages. Through an analysis of the data in terms of communicative acts and dimensions of engagement, we were able to identify the different constructions of roles and responsibilities at the three universities when engaging international students during the pandemic. These findings were interpreted in relation to the roles of universities in engaging with international students, and the value of a multimodal approach to researching engagement

Thickness dependence of superconductivity and superconductor-insulator transition in ultrathin FeSe films on SrTiO3(001) substrate

Interface-enhanced high-temperature superconductivity in one unit-cell (UC) FeSe film on SrTiO3(001) (STO) substrate has recently attracted much attention in condensed matter physics and material science. Here, by ex situ transport measurements, we report on the superconductivity in FeSe ultra-thin films with different thickness on STO substrate. We find that the onset superconducting transition temperature (Tc) decreases with increasing film thickness of FeSe, which is opposite to the behavior usually observed in traditional superconductor films. By systematic post-annealing of 5 UC FeSe films, we observe an insulator to superconductor transition, which is accompanied with a sign change of the dominated charge carriers from holes to electrons at low temperatures according to the corresponding Hall measurement

Representation of international students on Australian university websites: A critical multimodal discourse analysis

University websites play a pivotal role in the recruitment of international students for Australian universities, in particular at a time of fierce global competition. These websites make an interesting specialised genre for discourse analysis. This article conceptualises university websites as multimodal texts employing language and other semiotic resources such as images to represent international students in the context of shifting conceptualisations of international student education. Based on a qualitative inquiry into the webpages for international students on the official websites of three Australian universities, the article shows how the universities categorise international students and represent them in perceived activities and interpersonal relations through language and other modalities. The discursive representation of international students by the three Australian universities is discussed in relation to conceptual shifts in international student education, diversity management and multimodal discourse analysis. The article concludes with implications for international student representation and university webpage desUniversity websites play a pivotal role in the recruitment of international students for Australian universities, in particular at a time of fierce global competition. These websites make an interesting specialised genre for discourse analysis. This article conceptualises university websites as multimodal texts employing language and other semiotic resources such as images to represent international students in the context of shifting conceptualisations of international student education. Based on a qualitative inquiry into the webpages for international students on the official websites of three Australian universities, the article shows how the universities categorise international students and represent them in perceived activities and interpersonal relations through language and other modalities. The discursive representation of international students by the three Australian universities is discussed in relation to conceptual shifts in international student education, diversity management and multimodal discourse analysis. The article concludes with implications for international student representation and university webpage design

Electron interaction-driven insulating ground state in Bi2Se3 topological insulators in the two dimensional limit

We report a transport study of ultrathin Bi2Se3 topological insulators with thickness from one quintuple layer to six quintuple layers grown by molecular beam epitaxy. At low temperatures, the film resistance increases logarithmically with decreasing temperature, revealing an insulating ground state. The sharp increase of resistance with magnetic field, however, indicates the existence of weak antilocalization, which should reduce the resistance as temperature decreases. We show that these apparently contradictory behaviors can be understood by considering the electron interaction effect, which plays a crucial role in determining the electronic ground state of topological insulators in the two dimensional limit.Comment: 4 figure

Simultaneous electrical-field-effect modulation of both top and bottom Dirac surface states of epitaxial thin films of three-dimensional topological insulators

It is crucial for the studies of the transport properties and quantum effects related to Dirac surface states of three-dimensional topological insulators (3D TIs) to be able to simultaneously tune the chemical potentials of both top and bottom surfaces of a 3D TI thin film. We have realized this in molecular beam epitaxy-grown thin films of 3D TIs, as well as magnetic 3D TIs, by fabricating dual-gate structures on them. The films could be tuned between n-type and p-type by each gate alone. Combined application of two gates can reduce the carrier density of a TI film to a much lower level than with only one of them and enhance the film resistance by 10000 %, implying that Fermi level is tuned very close to the Dirac points of both top and bottom surface states without crossing any bulk band. The result promises applications of 3D TIs in field effect devices.Comment: 19 pages, 4 figures, accepted by Nano Letters, forthcomin