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Browsing by Author "Wang, Li"

Now showing 1 - 7 of 7
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    Automated Bedform Identification-A Meta-Analysis of Current Methods and the Heterogeneity of Their Outputs
    Scheiber, Leon; Zomer, Judith; Wang, Li; Cisneros, Julia; Gutierrez, Ronald R.; Lefebvre, Alice (American Geophysical Union, 2024-03-25)
    Ongoing efforts to characterize underwater dunes have led to a considerable number of freely available tools that identify these bedforms in a (semi-)automated way. However, these tools differ with regard to their research focus and appear to produce results that are far from unequivocal. We scrutinize this assumption by comparing the results of five recently published dune identification tools in a comprehensive meta-analysis. Specifically, we analyze dune populations identified in three bathymetries under diverse flow conditions and compare the resulting dune characteristics in a quantitative manner. Besides the impact of underlying definitions, it is shown that the main heterogeneity arises from the consideration of a secondary dune scale, which has a significant influence on statistical distributions. Based on the quantitative results, we discuss the individual strengths and limitations of each algorithm, with the aim of outlining adequate fields of application. However, the concerted bedform analysis and subsequent combination of results have another benefit: the creation of a benchmarking data set which is inherently less biased by individual focus and therefore a valuable instrument for future validations. Nevertheless, it is apparent that the available tools are still very specific and that end-users would profit by their merging into a universal and modular toolbox.
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    Crawling on the World Wide Web
    Wang, Li; Fox, Edward A. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2002)
    As the World Wide Web grows rapidly, a web search engine is needed for people to search through the Web. The crawler is an important module of a web search engine. The quality of a crawler directly affects the searching quality of such web search engines. Given some seed URLs, the crawler should retrieve the web pages of those URLs, parse the HTML files, add new URLs into its buffer and go back to the first phase of this cycle. The crawler also can retrieve some other information from the HTML files as it is parsing them to get the new URLs. This paper describes the design, implementation, and some considerations of a new crawler programmed as an learning exercise and for possible use for experimental studies.
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    FPGA Dynamic Power Minimization through Placement and Routing Constraints
    Wang, Li; French, Matthew; Davoodi, Azadeh; Agarwal, Deepak (2006-08-29)
    Field-programmable gate arrays (FPGAs) are pervasive in embedded systems requiring low-power utilization. A novel power optimization methodology for reducing the dynamic power consumed by the routing of FPGA circuits by modifying the constraints applied to existing commercial tool sets is presented. The power optimization techniques influence commercial FPGA Place and Route (PAR) tools by translating power goals into standard throughput and placement-based constraints. The Low-Power Intelligent Tool Environment (LITE) is presented, which was developed to support the experimentation of power models and power optimization algorithms. The generated constraints seek to implement one of four power optimization approaches: slack minimization, clock tree paring, N-terminal net colocation, and area minimization. In an experimental study, we optimize dynamic power of circuits mapped into 0.12 μm Xilinx Virtex-II FPGAs. Results show that several optimization algorithms can be combined on a single design, and power is reduced by up to 19.4%, with an average power savings of 10.2%.
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    Genus-Wide Characterization of Bumblebee Genomes Provides Insights into Their Evolution and Variation in Ecological and Behavioral Traits
    Sun, Cheng; Huang, Jiaxing; Wang, Yun; Zhao, Xiaomeng; Su, Long; Thomas, Gregg W. C.; Zhao, Mengya; Zhang, Xingtan; Jungreis, Irwin; Kellis, Manolis; Vicario, Saverio; Sharakhov, Igor V.; Bondarenko, Semen M.; Hasselmann, Martin; Kim, Chang N.; Paten, Benedict; Penso-Dolfin, Luca; Wang, Li; Chang, Yuxiao; Gao, Qiang; Ma, Ling; Ma, Lina; Zhang, Zhang; Zhang, Hongbo; Zhang, Huahao; Ruzzante, Livio; Robertson, Hugh M.; Zhu, Yihui; Liu, Yanjie; Yang, Huipeng; Ding, Lele; Wang, Quangui; Ma, Dongna; Xu, Weilin; Liang, Cheng; Itgen, Michael W.; Mee, Lauren; Cao, Gang; Zhang, Ze; Sadd, Ben M.; Hahn, Matthew W.; Schaack, Sarah; Barribeau, Seth M.; Williams, Paul H.; Waterhouse, Robert M.; Mueller, Rachel Lockridge (Oxford University Press, 2021-02-01)
    Bumblebees are a diverse group of globally important pollinators in natural ecosystems and for agricultural food production. With both eusocial and solitary life-cycle phases, and some social parasite species, they are especially interesting models to understand social evolution, behavior, and ecology. Reports of many species in decline point to pathogen transmission, habitat loss, pesticide usage, and global climate change, as interconnected causes. These threats to bumblebee diversity make our reliance on a handful of well-studied species for agricultural pollination particularly precarious. To broadly sample bumblebee genomic and phenotypic diversity, we de novo sequenced and assembled the genomes of 17 species, representing all 15 subgenera, producing the first genus-wide quantification of genetic and genomic variation potentially underlying key ecological and behavioral traits. The species phylogeny resolves subgenera relationships, whereas incomplete lineage sorting likely drives high levels of gene tree discordance. Five chromosome-level assemblies show a stable 18-chromosome karyotype, with major rearrangements creating 25 chromosomes in social parasites. Differential transposable element activity drives changes in genome sizes, with putative domestications of repetitive sequences influencing gene coding and regulatory potential. Dynamically evolving gene families and signatures of positive selection point to genus-wide variation in processes linked to foraging, diet and metabolism, immunity and detoxification, as well as adaptations for life at high altitudes. Our study reveals how bumblebee genes and genomes have evolved across the Bombus phylogeny and identifies variations potentially linked to key ecological and behavioral traits of these important pollinators.
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    Intermittent Water Supply Management, Household Adaptation, and Drinking Water Quality: A Comparative Study in Two Chinese Provinces
    Li, Hongxing; Cohen, Alasdair; Li, Zheng; Lv, Shibo; He, Zuan; Wang, Li; Zhang, Xinyi (MDPI, 2020-05-12)
    Intermittent water supply (IWS) is a relatively common phenomenon across the world as well as in rural and peri-urban areas across China, though there has been little IWS-focused research from China published to date. IWS consumers typically adopt a range of strategies to cope with insufficient water supply, poor drinking water quality, and associated inconveniences. In this study, we collected a range of data from small-scale utilities and households in two IWS systems and two continuous water supply (CWS) systems, as well as from comparison groups, in Shandong and Hubei provinces. Data collection included water quality testing, interviews, and surveys on behavioral adaptations, coping strategies, water-related health perceptions, and other metrics of consumer satisfaction. Overall, we found that the IWS coping strategies employed in northern China (Shandong) were associated with generally safe, but inconvenient, water access, whereas adaptation strategies observed in southern China (Hubei) appeared to improve convenience, but not water quality. Compared to the CWS comparison groups, we did not observe significant differences in water- and sanitation-related behaviors in the IWS groups, suggesting interventions to increase adaptive and protective behaviors at the household level might further improve safe water access for households living with IWS. Overall, although the water supply infrastructure in these study areas appeared to be in relatively good condition, in contrast to reported data on IWS systems in other countries, we observed multiple risk factors associated with the water treatment and distribution processes in these IWS systems. Among policy recommendations, our results suggest that the implementation of Water Safety Plans in China would likely improve the management of drinking water treatment and, by extension, safe drinking water supply under conditions of IWS.
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    Recommendations for Design Parameters for Central Composite Designs with Restricted Randomization
    Wang, Li (Virginia Tech, 2006-08-15)
    In response surface methodology, the central composite design is the most popular choice for fitting a second order model. The choice of the distance for the axial runs, alpha, in a central composite design is very crucial to the performance of the design. In the literature, there are plenty of discussions and recommendations for the choice of alpha, among which a rotatable alpha and an orthogonal blocking alpha receive the greatest attention. Box and Hunter (1957) discuss and calculate the values for alpha that achieve rotatability, which is a way to stabilize prediction variance of the design. They also give the values for alpha that make the design orthogonally blocked, where the estimates of the model coefficients remain the same even when the block effects are added to the model. In the last ten years, people have begun to realize the importance of a split-plot structure in industrial experiments. Constructing response surface designs with a split-plot structure is a hot research area now. In this dissertation, Box and Hunters' choice of alpha for rotatablity and orthogonal blocking is extended to central composite designs with a split-plot structure. By assigning different values to the axial run distances of the whole plot factors and the subplot factors, we propose two-strata rotatable splitplot central composite designs and orthogonally blocked split-plot central composite designs. Since the construction of the two-strata rotatable split-plot central composite design involves an unknown variance components ratio d, we further study the robustness of the two-strata rotatability on d through simulation. Our goal is to provide practical recommendations for the value of the design parameter alpha based on the philosophy of traditional response surface methodology.
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    Wood for Application in Electrochemical Energy Storage Devices
    Shan, Xiaofei; Wu, Jing; Zhang, Xiaotao; Wang, Li; Yang, Junli; Chen, Zhangjing; Yu, Jianfang; Wang, Ximing (Elsevier, 2021-12-22)
    Nowadays, achieving powerful electrochemical energy conversion and storage devices is a major challenge of our society. Wood is a biodegradable and renewable material that naturally has a hierarchical porous structure, excellent mechanical performance, and versatile physicochemical properties. Wood-based materials and its derivatives are endowed with great potential as resources to fabricate advanced materials for energy storage, flexible electronics, and clean energy. Herein, we comprehensively overview the methodologies applied for the synthesis of various electrochemical energy storage systems and devices (e.g., supercapacitor, battery, catalytic hydrogen evolution, etc.), the strategies for tailoring the structures and conductivity, as well as their impact on electrochemical performance (energy and power density and long-term durability). Finally, an outlook of future opportunities and prospects in the synthesis and application of electrochemical energy storage is also presented.