V2X Content Distribution Based on Batched Network Coding with Distributed Scheduling

Content distribution is an application in intelligent transportation system to assist vehicles in acquiring information such as digital maps and entertainment materials. In this paper, we consider content distribution from a single roadside infrastructure unit to a group of vehicles passing by it. To combat the short connection time and the lossy channel quality, the downloaded contents need to be further shared among vehicles after the initial broadcasting phase. To this end, we propose a joint infrastructure-to-vehicle (I2V) and vehicle-to-vehicle (V2V) communication scheme based on batched sparse (BATS) coding to minimize the traffic overhead and reduce the total transmission delay. In the I2V phase, the roadside unit (RSU) encodes the original large-size file into a number of batches in a rateless manner, each containing a fixed number of coded packets, and sequentially broadcasts them during the I2V connection time. In the V2V phase, vehicles perform the network coded cooperative sharing by re-encoding the received packets. We propose a utility-based distributed algorithm to efficiently schedule the V2V cooperative transmissions, hence reducing the transmission delay. A closed-form expression for the expected rank distribution of the proposed content distribution scheme is derived, which is used to design the optimal BATS code. The performance of the proposed content distribution scheme is evaluated by extensive simulations that consider multi-lane road and realistic vehicular traffic settings, and shown to significantly outperform the existing content distribution protocols.Comment: 12 pages and 9 figure

Electrical Tunable Spintronic Neuron with Trainable Activation Function

Spintronic devices have been widely studied for the hardware realization of artificial neurons. The stochastic switching of magnetic tunnel junction driven by the spin torque is commonly used to produce the sigmoid activation function. However, the shape of the activation function in previous studies is fixed during the training of neural network. This restricts the updating of weights and results in a limited performance. In this work, we exploit the physics behind the spin torque induced magnetization switching to enable the dynamic change of the activation function during the training process. Specifically, the pulse width and magnetic anisotropy can be electrically controlled to change the slope of activation function, which enables a faster or slower change of output required by the backpropagation algorithm. This is also similar to the idea of batch normalization that is widely used in the machine learning. Thus, this work demonstrates that the algorithms are no longer limited to the software implementation. They can in fact be realized by the spintronic hardware using a single device. Finally, we show that the accuracy of hand-written digit recognition can be improved from 88% to 91.3% by using these trainable spintronic neurons without introducing additional energy consumption. Our proposals can stimulate the hardware realization of spintronic neural networks.Comment: 26 pages, 9 figure

Impact of lifestyle and psychological resilience on survival among the oldest-old in China: a cohort study

IntroductionHealthy lifestyles and psychological resilience are important factors influencing the life expectancy of the oldest-old (≥80 years). Stratified by urban and rural groups, this study used a 10-year cohort to examine the mechanism of lifestyle and psychological resilience on the survival of the oldest-old in China.MethodsThis study used the China Longitudinal Healthy Longevity Survey datasets spanning from 2008 to 2018, and 9,250 eligible participants were included. The primary outcome variable was all-cause mortality, and independent variables included healthy lifestyle index and psychological resilience. Six covariates were included in the survival analysis and moderation-mediation model, such as gender and annual household income.ResultsThis study found that the oldest-old with five healthy lifestyles had the longest survival time, averaging 59.40 months for urban individuals and 50.08 months for rural individuals. As the lifestyle index increased, the survival rate significantly increased. The Cox regression showed that for the urban oldest-old, the lifestyle index served as a protective factor for survival outcomes. However, this effect lost statistical significance among rural oldest-old individuals. For urban oldest-old individuals, psychological resilience significantly mediated and moderated the effect of the lifestyle index on survival status, but the moderating effect was not statistically significant for the rural ones.DiscussionOverall, healthy lifestyles and psychological resilience can be effective in enhancing the survival of the oldest-old, and there are differences between urban and rural population, so different interventions should be adopted for urban and rural areas to achieve longer life in China

Parity Splitting and Polarized-Illumination Selection of Plasmonic Higher-Order Topological States

Topological states, originated from interactions between internal degree of freedoms (like spin and orbital) in each site and crystalline symmetries, offer a new paradigm to manipulate electrons and classical waves. The accessibility of spin degree of freedom has motivated much attention on spin-related topological physics. However, intriguing topological physics related to atomic-orbital parity, another binary degree of freedom, have not been exploited since accessing approaches on atomic orbitals are not well developed. Here, we theoretically discover spectral splitting of atomic-orbital-parity-dependent second-order topological states on a designer-plasmonic Kagome metasurface, and experimentally demonstrate it by exploiting the easy controllability of metaatoms. Unlike previous demonstrations on Hermitian higher-order topological insulators, radiative non-Hermicity of the metasurface enables far-field access into metaatomic-orbital-parity-dependent topological states with polarized illuminations. The atomic-orbital parity degree of freedom may generate more intriguing topological physics by interacting with different crystalline symmetries, and promise applications in polarization-multiplexing topological lasing and quantum emitters.Comment: 19 pages, 4 figure

Integrated Genomic Analysis of the Ubiquitin Pathway across Cancer Types

Protein ubiquitination is a dynamic and reversibleprocess of adding single ubiquitin molecules orvarious ubiquitin chains to target proteins. Here,using multidimensional omic data of 9,125 tumorsamples across 33 cancer types from The CancerGenome Atlas, we perform comprehensive molecu-lar characterization of 929 ubiquitin-related genesand 95 deubiquitinase genes. Among them, we sys-tematically identify top somatic driver candidates,including mutatedFBXW7with cancer-type-specificpatterns and amplifiedMDM2showing a mutuallyexclusive pattern withBRAFmutations. Ubiquitinpathway genes tend to be upregulated in cancermediated by diverse mechanisms. By integratingpan-cancer multiomic data, we identify a group oftumor samples that exhibit worse prognosis. Thesesamples are consistently associated with the upre-gulation of cell-cycle and DNA repair pathways, char-acterized by mutatedTP53,MYC/TERTamplifica-tion, andAPC/PTENdeletion. Our analysishighlights the importance of the ubiquitin pathwayin cancer development and lays a foundation fordeveloping relevant therapeutic strategies

Molecular characterization and clinical relevance of metabolic expression subtypes in human cancers.

Metabolic reprogramming provides critical information for clinical oncology. Using molecular data of 9,125 patient samples from The Cancer Genome Atlas, we identified tumor subtypes in 33 cancer types based on mRNA expression patterns of seven major metabolic processes and assessed their clinical relevance. Our metabolic expression subtypes correlated extensively with clinical outcome: subtypes with upregulated carbohydrate, nucleotide, and vitamin/cofactor metabolism most consistently correlated with worse prognosis, whereas subtypes with upregulated lipid metabolism showed the opposite. Metabolic subtypes correlated with diverse somatic drivers but exhibited effects convergent on cancer hallmark pathways and were modulated by highly recurrent master regulators across cancer types. As a proof-of-concept example, we demonstrated that knockdown of SNAI1 or RUNX1—master regulators of carbohydrate metabolic subtypes-modulates metabolic activity and drug sensitivity. Our study provides a system-level view of metabolic heterogeneity within and across cancer types and identifies pathway cross-talk, suggesting related prognostic, therapeutic, and predictive utility

Efficient data dissemination protocols for V2X communication networks

With the rapid development of intelligent transportation system (ITS) technology and applications, the real-time wireless connectivity of moving vehicles has attracted increasing attention in the academia and industries. Relying on vehicle-to-everything (V2X) communication, vehicles are enabled to communicate with vehicles directly, as well as with roadside infrastructures. V2X communication is able to support a variety of applications to address road safety concern and support commercial or regulatory ITS services. Confronted by dynamic vehicular environment and stringent latency requirements, the design of efficient V2X communication protocols are of great relevance. In this thesis, we aim to design efficient data dissemination schemes for a number of realistic V2X use-cases. To this end, we utilize techniques such as network coding and Markov chain modeling, and focus on media access control (MAC) layer enhancement and scheduling optimization. Firstly, the impact of the contention-window size of the IEEE 802.11p standard for periodic broadcast of short messages using dedicated short-range communication (DSRC) among vehicles is investigated. We apply Markov chain to model the periodic broadcasting behavior (such as broadcasting basic safety message) of the vehicles under the IEEE 802.11p MAC layer standard for both saturated and unsaturated network conditions. We attain enhancements by analytically optimizing the window size for maximizing the communication throughput, which are then verified by computer simulations. Secondly, a reliable basic safety message (BSM) dissemination scheme is proposed for the non-line-of-sight (NLOS) road intersection scenario. The periodic BSM exchanges by all vehicles are particularly crucial for preventing car collisions at road intersections without traffic signals. Large concrete buildings and obstacles may create a NLOS condition, leading to severe signal blockage. In order to address this problem and meet the timeliness requirement of BSM dissemination, we exploit random linear network coding and introduce controlled repetitive transmission patterns. Two promising network-coded relaying schemes are proposed to improve the reliability and scalability of the system. Thirdly, an efficient V2X content distribution scheme based on batched sparse (BATS) code (a two-layer network code) with distributed scheduling is studied, in which digital maps or entertainment content are distributed from a roadside unit (RSU) to a group of vehicles passing by. To improve the transmission reliability in the lossy vehicular communication environment and possibly disconnected RSU cells, the original file is encoded with a BATS code for broadcast by a RSU, then a cooperative vehicle-to-vehicle (V2V) data sharing phase follows to repair the packets lost in the first I2V phase. To reduce the total content-distribution delay, a utility-based distributed algorithm is proposed to efficiently schedule the cooperative V2V data sharing phase. The proposed content distribution scheme is evaluated by extensive computer simulations, considering multi-lane road and realistic vehicular traffic settings, and shown to significantly reduce the transmission delay and communication overhead compared with known protocols such as CodeOn and CodeTorrent. Finally, the problem of optimal scheduling for multi-hop V2V video streaming with network coding (applied to mitigate the well-known curse of exponential multi-hop throughput drop) in a Cellular-V2X setting is studied. The proposed network-coded scheduling algorithm considers not just the direct V2V communication link, but also the RF overhearing link, in the multi-hop V2V network. To further improve the system performance, channel reuse is applied for long multi-hop networks. Simulation results show that the proposed network-coded scheduling scheme achieves substantial end-to-end throughput (achievable normalized generation rate) gain over conventional packet erasure correction coding schemes.Doctor of Philosoph

Essays on sustainable finance across asset classes : empirical evidence from China and US

This thesis contributes to the growing body of literature on sustainable finance by investigating the financial implications of environmental, social, and governance (ESG) risks and opportunities from the perspective of investors and companies. Utilising novel data from the United States (US) and China, I empirically examine how ESG factors are priced in different financial assets, including options, equities, and bonds, throughout the four main chapters. The first main chapter investigates the upside potential and downside risk of responsible investing that incorporate ESG factors into the investment process and decision-making. By using the option market measures of 46 US financial services companies, I find that financial services companies with highly-rated responsible processes are associated with higher upside potential and lower downside risk; however, I do not observe the same effect for investors who are simply Principles for Responsible Investment (PRI) members. The second chapter examines the return on investment (ROI) in human resource management (HRM) practices using an economics-based approach. In particular, I attempt to answer whether a firm's investment in HRM activities reduces the cost of bond issuance. Using a sample of 172 Chinese nonfinancial companies, I find that firms with superior employee relations management are associated with approximately 18.79 basis points lower bond issuance spreads, equivalent to an annual saving of RMB 15.25 million (or USD 2.39 million). Furthermore, the estimated ROI in HRM through the channel of financing cost savings is about 1.24% per annum. Next, I empirically investigate the relationship between corporate environmental performance (CEP) and stock market performance, particularly through the mechanisms of consumer and employee preferences. By using a sample of 629 Chinese nonfinancial companies, I find that firms with superior carbon risk management are associated with higher risk-adjusted returns when there is high consumer demand (i.e., in consumer goods sectors), but an insignificant effect is observed when consumer demand is low (i.e., in non-consumer sectors). Furthermore, I find that employee demand also mediates the corporate environmental and financial performance relationship. The findings suggest that for sectors in which the customer's preference does not play a denominate role in affecting returns (i.e., non-consumer firms), the employee's power is essential in influencing the level of expected returns. The mediating effect of employee preference is particularly significant for firms with more human capital. Finally, the fourth empirical chapter evaluates the financial performance of impact investors who invest with dual objectives in China. I specifically examine whether environmental impact investing adds value to financial institutions by drawing new inferences from their performance in stock returns. The results indicate that financial companies that proactively incorporate environmental impacts in their due diligence and financing decision-making show higher stock returns than firms that poorly manage their indirect environmental impacts. In other words, institutional investors that pursue impact financing show better stock return performance than those that do not