408 research outputs found
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Supercapacitors in Micro- and Mild Hybrids with Lithium Titanate Oxide Batteries: Vehicle Simulations and Laboratory Tests
The use of lithium titanate Oxide (LTO) batteries with supercapacitors in micro- and mild hybrid vehicles has been studied. The study involves vehicle simulations and laboratory tests of carbon/carbon supercapacitors and 20Ah LTO cells from EIG, Korea. Cycle testing of the LTO cells/module on a cycle to simulate their use with supercapacitors indicated that their charge acceptance was excellent even at a charging power of 2000W (500W/cell). The test data indicated that the LTO battery would be an excellent choice for micro-hybrid applications. Simulations of micro- and mild hybrid vehicle operation have been run using lead-acid and EIG LTO battery technologies in 16V and 48V system. It is clear from the results that the LTO batteries can function well in both the micro- and mild hybrids. The LTO batteries are much smaller than the lead-acid batteries and are more efficient. The LTO batteries had an efficiency of 95-97% while the lead-acid batteries had an efficiency of 85-88%. The effect on fuel economy of the higher efficiency of the LTO batteries was not significant for either the FUDS or highway driving cycle. This was true for even the accessory load of 800W
Model selection methods and their application in genome-wide association studies
Ph.DDOCTOR OF PHILOSOPH
Voltammetry in low concentration of electrolyte supported by ionic latex suspensions
Since ionic conductivity has a linear relation with the square of the number of charge,
ionic latex particles with a huge number of the charge could provide high conductance.
It is expected that addition of only a small amount of latex particles into voltammetric
solution enhances the conductance so much that voltammograms can be measured,
overcoming ohmic drop. Conductivity of latex suspensions of polystyrenepolystyrenesulfonic
acid with volume fractions less than 0.02, which were well
deionized by centrifugation, was determined by ac-impedance at two parallel wire
electrodes. Since the resistance was determined by the dependence of the in-phase
component on the electrode distance, it did not include participation of electric double
layers or adsorption of latex. The relationship between conductivity and a diffusion
coefficient stated that the conductivity of the suspension was provided mainly by
diffusion of latex particles with multiple charges rather than that of the counterion. The
suspension with [H^+] = 10^-5 M, corresponding to 8.9 x 10^5 number mm^-3, including
hydrogen gas showed a voltammetric oxidation peak of hydrogen, whereas hydrochloric
acid with [HCl] = 10^-5M showed a resistive current-potential curve
Unified Data Management and Comprehensive Performance Evaluation for Urban Spatial-Temporal Prediction [Experiment, Analysis & Benchmark]
The field of urban spatial-temporal prediction is advancing rapidly with the
development of deep learning techniques and the availability of large-scale
datasets. However, challenges persist in accessing and utilizing diverse urban
spatial-temporal datasets from different sources and stored in different
formats, as well as determining effective model structures and components with
the proliferation of deep learning models. This work addresses these challenges
and provides three significant contributions. Firstly, we introduce "atomic
files", a unified storage format designed for urban spatial-temporal big data,
and validate its effectiveness on 40 diverse datasets, simplifying data
management. Secondly, we present a comprehensive overview of technological
advances in urban spatial-temporal prediction models, guiding the development
of robust models. Thirdly, we conduct extensive experiments using diverse
models and datasets, establishing a performance leaderboard and identifying
promising research directions. Overall, this work effectively manages urban
spatial-temporal data, guides future efforts, and facilitates the development
of accurate and efficient urban spatial-temporal prediction models. It can
potentially make long-term contributions to urban spatial-temporal data
management and prediction, ultimately leading to improved urban living
standards.Comment: 14 pages, 3 figures. arXiv admin note: text overlap with
arXiv:2304.1434
Pathway-based analysis using reduced gene subsets in genome-wide association studies
<p>Abstract</p> <p>Background</p> <p>Single Nucleotide Polymorphism (SNP) analysis only captures a small proportion of associated genetic variants in Genome-Wide Association Studies (GWAS) partly due to small marginal effects. Pathway level analysis incorporating prior biological information offers another way to analyze GWAS's of complex diseases, and promises to reveal the mechanisms leading to complex diseases. Biologically defined pathways are typically comprised of numerous genes. If only a subset of genes in the pathways is associated with disease then a joint analysis including all individual genes would result in a loss of power. To address this issue, we propose a pathway-based method that allows us to test for joint effects by using a pre-selected gene subset. In the proposed approach, each gene is considered as the basic unit, which reduces the number of genetic variants considered and hence reduces the degrees of freedom in the joint analysis. The proposed approach also can be used to investigate the joint effect of several genes in a candidate gene study.</p> <p>Results</p> <p>We applied this new method to a published GWAS of psoriasis and identified 6 biologically plausible pathways, after adjustment for multiple testing. The pathways identified in our analysis overlap with those reported in previous studies. Further, using simulations across a range of gene numbers and effect sizes, we demonstrate that the proposed approach enjoys higher power than several other approaches to detect associated pathways.</p> <p>Conclusions</p> <p>The proposed method could increase the power to discover susceptibility pathways and to identify associated genes using GWAS. In our analysis of genome-wide psoriasis data, we have identified a number of relevant pathways for psoriasis.</p
Effect of Grapevine Age on the Aroma Compounds in ‘Beihong’ Wine
The main aim of this study was to determine the influence of grapevine age (3, 6 and 12 years) on the aromacompounds in ‘Beihong’ wine. Aroma compounds in wine were analyzed by solid-phase microextractiongas chromatography-mass spectrometry (SPME-GC/MS). Thirty-three (33) volatile compounds wereidentified and quantified. The majority of aroma compounds were esters (20) and the concentrationof these totaled 90.63-92.82% (w/w) of the total aroma compounds; particularly, ethyl octanoate andethyl decanoate. Through the descriptive analysis aroma profile for ‘Beihong’ wine, the highest aromacontribution was from the fruity and floral series. As the age of the grapevine increased, the concentrationsof total volatiles and total odor activity values (OAVs) of the wines significantly increased (p < 0.001). Thissuggests that grapevine age could affect berry composition, enhance the content of wine aroma compoundsand improve wine quality
Fungal associates of the tree-killing bark beetle, Ips typographus, vary in virulence, ability to degrade conifer phenolics and influence bark beetle tunneling behavior
The bark beetle Ips typographus carries numerous fungi that could be assisting the beetle in colonizing live Norway spruce (Picea abies) trees. Phenolic defenses in spruce phloem are degraded by the beetle's major tree-killing fungus Endoconidiophora polonica, but it is unknown if other beetle associates can also catabolize these compounds. We compared the ability of five fungi commonly associated with I. typographus to degrade phenolic compounds in Norway spruce phloem. Grosmannia penicillata and Grosmannia europhioides were able to degrade stilbenes and flavonoids faster than E. polonica and grow on minimal growth medium with spruce bark constituents as the only nutrients. Furthermore, beetles avoided medium amended with phenolics but marginally preferred medium colonized by fungi. Taken together our results show that different bark beetle-associated fungi have complementary roles in degrading host metabolites and thus might improve this insect's persistence in well defended host tissues.acceptedVersio
Rethinking the Evaluation for Conversational Recommendation in the Era of Large Language Models
The recent success of large language models (LLMs) has shown great potential
to develop more powerful conversational recommender systems (CRSs), which rely
on natural language conversations to satisfy user needs. In this paper, we
embark on an investigation into the utilization of ChatGPT for conversational
recommendation, revealing the inadequacy of the existing evaluation protocol.
It might over-emphasize the matching with the ground-truth items or utterances
generated by human annotators, while neglecting the interactive nature of being
a capable CRS. To overcome the limitation, we further propose an interactive
Evaluation approach based on LLMs named iEvaLM that harnesses LLM-based user
simulators. Our evaluation approach can simulate various interaction scenarios
between users and systems. Through the experiments on two publicly available
CRS datasets, we demonstrate notable improvements compared to the prevailing
evaluation protocol. Furthermore, we emphasize the evaluation of
explainability, and ChatGPT showcases persuasive explanation generation for its
recommendations. Our study contributes to a deeper comprehension of the
untapped potential of LLMs for CRSs and provides a more flexible and
easy-to-use evaluation framework for future research endeavors. The codes and
data are publicly available at https://github.com/RUCAIBox/iEvaLM-CRS.Comment: Accepted by EMNLP 202
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