Adaptive multimodal fusion based similarity measures in music information retrieval

Ph.DDOCTOR OF PHILOSOPH

Causes and Consequences of the Evolution of Mutation Rate

As the ultimate source of all genetic variation, mutation is required for evolution. The mutation rate measures the rate at which mutations occur over time. How the mutation rate evolves and how it interacts with other evolutionary processes are still far from clearly understood. In this thesis, I employ individual-based simulations and aim to understand how the evolution of mutation rate interacts with other evolutionary forces such as mutation biases, selection for evolvability, genetic drift and the evolution of recombination rate. In Chapter 3, I studied the role of mutation bias (bias towards high mutation rate) in the evolution of mutation rate, which has been long ignored in the literature. I found that the effect of mutation bias on the evolution of mutation rate is significant when compared to that of other broadly promoted evolutionary forces such as natural selection, mutator hitchhiking, and genetic drift. Even in sexual populations, I found that mutation bias can still operate and drive the evolution of mutation rate. In Chapter 4, when the mutation rate (U) and recombination rate (R) are not allowed to evolve, I found that there exists an optimal mutation rate (Uopt), at which a population can achieve their maximal evolvability (E). Popula- tions displayed negative evolvability if U was above a critical value (Ucrit). Asexual and sexual populations showed similar relationships between E and U. Moreover, increasing R also increased E, Uopt, and Ucrit. In Chapter 5, I found that selection for evolvability cannot optimize U when it is allowed to evolve because U increased without bound — a phenomenon known as mutation rate catastrophe. In addition, the effect of mutation bias is much stronger than the selection for evolvability in sexual populations, indicating the selection for evolvability is not the only force that can affect the evolution of U and is a weak selection. However, U cannot be opti- mized when both forces are operating. Lastly, I found that selection can optimize the recombination rate for high evolvability. High R can prevent populations from experiencing the mutation rate catastrophe, although populations do not always evolve high R.Biology and Biochemistry, Department o

Evolving corporate social responsibility in China

With a unique cultural background and fast economic development, China’s adoption of corporate social responsibility (CSR) has become the center of discussion worldwide, and its successful implementation will have great significance for global sustainability. This paper aims to explore how CSR has given way to economic growth in China since the start of economic transition and its cultural, historical and political background, and how this has affected or been affected by the economic performance of firms. Thus, the recent calls for China to adopt CSR in its industries follow a period where the country arguably had one of the strongest implementations of CSR approaches in the world. This transition is considered in the context of a case study of a Chinese state-owned enterprise (SOE) and a group of small private firms in the same industrial sector in Zhengzhou City, Henan Province over a time span of eight years. While the CSR of the SOE has been steadily decreasing along with the change of ownership structure, its economic performance did not improve as expected. On the other hand, with a steady improvement in economic performance, the small private firms are showing a great reluctance to engage in CSR. The results indicate that implementation of CSR in China needs both the manager’s ethical awareness and the change of institutional framework. The results also raise the question as to whether CSR is a universal concept with a desired means of implementation across the developed and developing world

Efficiency Analysis of Scientific and Technological Innovation in Grain Production Based on Improved Grey Incidence Analysis

open access articleAnalyzing and evaluating the efficiency of scientific and technological innovation in grain production is conducive to the rational allocation of resources, promoting the development of scientific and technological innovation in grain production and providing guarantee for grain security. By refining the elements of grain production and scientific and technological innovation, an evaluation system of scientific and technological innovation in grain production is constructed. Firstly, combining linear programming together with the traditional grey synthetic incidence analysis model, a incidence analysis of the scientific and technological innovation indicators of grain production is carried out, and the key and secondary indexes affecting grain outputs are screened by an improved grey incidence analysis model. Secondly, based on DEA-Malmquist index model and taking the grain production process as the research object, the scientific and technological achievement transformation indicators are divided into pre-production, in-production and post-production indicators. The key indicators and secondary indicators of scientific and technological innovation of grain production in various cities of Henan Province from 2010 to 2019 are used to analyze the efficiency of scientific and technological innovation in each stage of grain production. The results show that: (1) The type of basic ability of scientific and technological innovation indicators and the transformation ability of scientific and technological innovation achievements are the major indicators influencing grain outputs, and the investment of basic resources of scientific and technological innovation and the transformation of scientific and technological innovation achievements are the most important to improve grain outputs. (2) In addition, the study reveals that the secondary indicators of the technological innovation efficiency of grain production based on the DEA-Malmquist index model are more efficient than the key indicators in the pre-production, in-production and post-production stages. And there are gaps in the scientific and technological innovation performance of grain production among cities in Henan Province, and the index of technological progress is the leading factor for the gap

Observation of acoustic spatiotemporal vortices

Vortices in fluids and gases have piqued the interest of human for centuries. Development of classical-wave physics and quantum mechanics highlighted wave vortices characterized by phase singularities and topological charges. In particular, vortex beams have found numerous applications in modern optics and other areas. Recently, optical spatiotemporal vortex states exhibiting the phase singularity both in space and time have been reported. Here, we report the first generation of acoustic spatiotemporal vortex pulses. We utilize an acoustic meta-grating with mirror-symmetry breaking as the spatiotemporal vortex generator. In the momentum-frequency domain, we unravel that the transmission spectrum functions exhibit a topological phase transition where the vortices with opposite topological charges are created or annihilated in pairs. Furthermore, with the topological textures of the nodal lines, these vortices are robust and exploited to generate spatiotemporal vortex pulse against structural perturbations and disorder. Our work paves the way for studies and applications of spatiotemporal structured waves in acoustics and other wave systems.Comment: 12 pages, 4 figure

Compositemap: A Novel Framework for Music Similarity Measure

10.1145/1571941.1572011Proceedings - 32nd Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 2009403-41

Computational and experimental demonstrations of one-pot tandem catalysis for electrochemical carbon dioxide reduction to methane

Electroreduction of carbon dioxide to hydrocarbons and oxygenates on copper involves reduction to a carbon monoxide adsorbate followed by further transformation to hydrocarbons and oxygenates. Simultaneous improvement of these processes over a single reactive site is challenging due to the linear scaling relationship of the binding strength of key intermediates. Herein, we report improved electroreduction of carbon dioxide by exploiting a one-pot tandem catalysis mechanism based on computational and electrochemical investigations. By constructing a well-defined copper-modified silver surface, adsorbed carbon monoxide generated on the silver sites is proposed to migrate to surface copper sites for the subsequent reduction to methane, which is consistent with insights gained from operando attenuated total reflectance surface enhanced infrared absorption spectroscopic investigations. Our results provide a promising approach for designing carbon dioxide electroreduction catalysts to enable one-pot reduction of products beyond carbon monoxide and formate

Query-document-dependent fusion: A case study of multimodal music retrieval

National Research Foundation (NRF) Singapore under International Research Centre @ Singapore Funding Initiativ

Oxygen induced promotion of electrochemical reduction of CO₂ via co-electrolysis

Harnessing renewable electricity to drive the electrochemical reduction of CO₂ is being intensely studied for sustainable fuel production and as a means for energy storage. Copper is the only monometallic electrocatalyst capable of converting CO₂ to value-added products, e.g., hydrocarbons and oxygenates, but suffers from poor selectivity and mediocre activity. Multiple oxidative treatments have shown improvements in the performance of copper catalysts. However, the fundamental underpinning for such enhancement remains controversial. Here, we combine reactivity, in-situ surface-enhanced Raman spectroscopy, and computational investigations to demonstrate that the presence of surface hydroxyl species by co-electrolysis of CO₂ with low concentrations of O₂ can dramatically enhance the activity of copper catalyzed CO2 electroreduction. Our results indicate that co-electrolysis of CO₂ with an oxidant is a promising strategy to introduce catalytically active species in electrocatalysis

Oxygen induced promotion of electrochemical reduction of CO₂ via co-electrolysis

Harnessing renewable electricity to drive the electrochemical reduction of CO₂ is being intensely studied for sustainable fuel production and as a means for energy storage. Copper is the only monometallic electrocatalyst capable of converting CO₂ to value-added products, e.g., hydrocarbons and oxygenates, but suffers from poor selectivity and mediocre activity. Multiple oxidative treatments have shown improvements in the performance of copper catalysts. However, the fundamental underpinning for such enhancement remains controversial. Here, we combine reactivity, in-situ surface-enhanced Raman spectroscopy, and computational investigations to demonstrate that the presence of surface hydroxyl species by co-electrolysis of CO₂ with low concentrations of O₂ can dramatically enhance the activity of copper catalyzed CO2 electroreduction. Our results indicate that co-electrolysis of CO₂ with an oxidant is a promising strategy to introduce catalytically active species in electrocatalysis