Wisent: Robust Downstream Communication and Storage for Computational RFIDs

Computational RFID (CRFID) devices are emerging platforms that can enable perennial computation and sensing by eliminating the need for batteries. Although much research has been devoted to improving upstream (CRFID to RFID reader) communication rates, the opposite direction has so far been neglected, presumably due to the difficulty of guaranteeing fast and error-free transfer amidst frequent power interruptions of CRFID. With growing interest in the market where CRFIDs are forever-embedded in many structures, it is necessary for this void to be filled. Therefore, we propose Wisent-a robust downstream communication protocol for CRFIDs that operates on top of the legacy UHF RFID communication protocol: EPC C1G2. The novelty of Wisent is its ability to adaptively change the frame length sent by the reader, based on the length throttling mechanism, to minimize the transfer times at varying channel conditions. We present an implementation of Wisent for the WISP 5 and an off-the-shelf RFID reader. Our experiments show that Wisent allows transfer up to 16 times faster than a baseline, non-adaptive shortest frame case, i.e. single word length, at sub-meter distance. As a case study, we show how Wisent enables wireless CRFID reprogramming, demonstrating the world's first wirelessly reprogrammable (software defined) CRFID.Comment: Accepted for Publication to IEEE INFOCOM 201

Learning Patterns of Engineering Students in a Singapore Tertiary Education Context and the Implications for Continuing Education in the Field of Engineering

In 1997, Singapore implemented radical changes to its education curricula to foster deep, self-directed learning which were thought to be important for lifelong learning. The aim of this study was to establish if there was any evidence that Singapore tertiary students, having been through the revised curricula, had indeed developed desirable learning patterns for continuing education. The samples comprised polytechnic Engineering undergraduates from the Year 1 (N=638), Year 2 (N=616) and Year 3 (N=705) cohorts. The study also included a control sample of working adults (Professionals) (N=140) who had returned for continuing education. A mixed methods design was executed with a cross-sectional study using the 100-item English version of Vermunt's Inventory of Learning Styles, together with semi-structured group interviews. A flexible learning pattern was reported to be common among undergraduates. Besides that, a prove-yourself directed pattern was reported by first and third year students, while a passive-idealistic pattern was indicated by second year students. The other two patterns reported in each group were variations of the reproduction and undirected patterns. The meaning directed and application directed learning patterns were not clearly distinguishable among the undergraduates. Sub-scale scores related to deep processing and self regulation strategies were not significantly higher in the second and third years, while scores for stepwise (surface) processing and external regulation were not lower. There seemed to be insufficient evidence to indicate that the changes in the curricula by the Singapore Ministry of Education and the polytechnic were effective in fostering the desired learning patterns. Among the Professionals, the meaning and application directed learning patterns were more clearly distinguishable. Subscale scores related to the use of knowledge and vocation were significantly higher than for the undergraduates. Working adults appear to have a stronger conception that learning was for the useful application of knowledge, and were clearer in their motives to enhance their vocation through their studies compared with the undergraduates. This suggested that learning patterns could be modified if learning conceptions and motives could be changed. This study has extended the understanding of learning pattern development particularly in a Singapore context, and generally in the wider Asian context. Cultural and educational contexts appear to play a role in influencing students’ learning conceptions and motives which, in turn, shape their learning patterns. Interventions that superficially manipulate the learning environment have limited effect in changing learning patterns. To bring about desired changes, all four domains of a learner – learning conceptions, motives, regulation and processing strategies, need to be addressed. This remains a challenge for institutions of higher learning and has implications for educational policy, curricula design and delivery, instructional approaches, assessments and other factors that impact the learner and the learning environment

Structural insights into HIV-1 capsid assembly, maturation and stability by cryo-electron tomography

Human immunodeficiency virus type 1 (HIV-1) is an enveloped lentivirus from the family Retroviridae which infects CD4+ T-lymphocytes in a human host, leading to Acquired Immunodeficiency Syndrome (AIDS) if untreated. A subset of retroviruses, most notably lentiviruses such as HIV-1, are unique in their ability to infect non-dividing cells. To do this, the reverse transcribed viral genome must be trafficked across an intact nuclear membrane and integrated into the host cell genome. The viral capsid plays a central role in this process. The first stage of capsid assembly is polymerisation of the viral polyprotein Gag via its CA (capsid) domain into a hexagonal immature lattice, forming a truncated sphere. The viral protease cleaves Gag and frees the CA domain, which rearranges to form a conical capsid around the viral genome, built from CA hexamers and pentamers. Despite advances in recent years, many open questions remain about immature Gag lattice assembly, maturation and modulation of capsid stability by host factors upon infection. One key question that has persisted in the field is how the remarkable structural transition between the immature Gag lattice and the mature CA lattice is achieved, which involves breaking almost all of the interactions stabilising the immature lattice. To address this, I applied cryo-electron tomography (cryo-ET) and subtomogram averaging to obtain high resolution structures of immature and mature CA in a panel of HIV-1 constructs containing different combinations of proteolytic cleavage sites inactivated by mutation. Unexpectedly, proteolytic processing directly on either side of CA was sufficient for mature lattice formation at low frequencies. I also show that a beta-hairpin domain at the CA N-terminus, previously proposed to be a structural switch, is dispensable for maturation. Instead, destabilisation of a six-helix bundle between the CA C-terminus and the adjacent SP1 peptide is the main structural determinant of maturation. Viral maturation is tightly linked to immature Gag lattice assembly, but many details such as the basic unit of lattice assembly remain unclear. The immature lattice is maintained by inter- and intra-hexamer interactions but is not a complete sphere, and the structure of Gag at discontinuous lattice edges is unknown. I implemented a new workflow to obtain Gag lattice structures by subtomogram classification of a cryo-ET data set of intact HIV-1 virions. These structures show that Gag forms novel, incomplete hexamers at lattice edges and that the CA-SP1 region forms ordered helical bun- dles in partial hexamers. Molecular dynamics simulations suggest that these partial bundles exhibit increased an tendency to unfold, suggesting a role of partial hexamer structures in initiation of maturation. Capsid stability after cell entry is important to prevent degradation of the viral RNA genome, and is modulated by small molecules such as inositol hexakisphosphate (IP6) and host proteins, including cleavage and polyadenylation specific factor 6 (CPSF6) and nucleoporin 153 (Nup153). A combination of CA pentamers and hexamers that flex to adopt different curvatures provides many different potential interfaces for cofactor binding. I developed a workflow to routinely obtain near-atomic resolution structures of CA hexamers and pentamers, by subtomogram averaging of conical, IP6-stabilised in vitro CA assemblies. These were used to investigate CPSF6 and Nup153 binding to pentamers and the effect of lattice curvature on the common binding pocket for these factors. The structures obtained show that CPSF6 and Nup153 do not bind to pentamers at the concentrations used, and that lattice flexibility can modulate Nup153 binding to hexamers

Does competition only impact on insolvency risk? New evidence from the Chinese banking industry

Purpose- This paper investigates the impact of competition on credit risk, liquidity risk, capital risk and insolvency risk in the Chinese banking industry during the period 2003-2013. Design/methodology/approach- This study uses a Generalized Method of Moments (GMM) system estimator to examine the impact of competition on risk. In particular, translog specifications are used to measure the competition and insolvency risk. Findings- The results show that greater competition within each bank ownership type (state-owned commercial banks, joint-stock commercial banks and city commercial banks) leads to higher credit risk, higher liquidity risk, higher capital risk, but lower insolvency risk. Originality- This paper is the first piece of research testing the impact of competition on different types of risk in banking industry and it further contributes to the empirical literature by using a more accurate competition indicator (efficiency-adjusted Lerner index) and a more precise insolvency risk indicator (stability inefficiency)

Profitability of Commercial Banks revisited: New Evidence from oil and non-oil exporting countries in the MENA region

This paper investigates the determinants of commercial bank profitability in oil and non-oil countries of the Middle East and North Africa (MENA) region using data from 11 countries over the period 2004–2014. Since banks are under no obligation to fill reports to Bankscope database, irregular reporting banks are omitted from the sample and the model is re-estimated using only regular reporting banks, and a comparative analysis between total banks' sample and regular reporting banks' sample is provided. Using the two-step system GMM and fixed effects models, the results indicate that credit risk is negative and highly significant when irregular reporting banks are omitted from the sample particularly in non-oil countries unlike the oil countries case, which indicates that adding irregular reporting banks to the sample could lead to bias in some estimated coefficients if they constitute a considerable percentage of the total banks' sample. Diversification is a key determinant for profitability in oil countries. No enough evidence to support the impact of financial inclusion and financial openness on bank profitability. In addition, the global financial crisis has significantly affected bank profitability in oil countries. Several policy implications are provided to the bank management to follow based on each country group

The impacts of risk-taking behaviour and competition on technical efficiency: evidence from the Chinese banking industry

This paper tests the impact of risk and competition on efficiency in the Chinese banking industry over the period 2003-2013. Comprehensive types of risk-taking behaviour are considered including credit risk, liquidity risk, capital risk, and insolvency risk. Competition is measured by the Lerner index. The results are cross-checked using an alternative econometric technique as well as an alternative competition indicator. The findings show that the technical and pure technical efficiencies of Chinese commercial banks are significantly and negatively affected by liquidity risk. They further show that greater competition precedes declines in technical and pure technical efficiencies of Chinese commercial banks. The results suggest that Chinese bank efficiency is significantly affected by bank diversification, banking sector development, stock market development, inflation and GDP growth rate. The findings also indicate that, compared to state-owned commercial banks, joint-stock commercial banks and city commercial banks have lower technical and pure technical efficiencies