| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Kristanl, Matej, et al.
(författare)
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The Seventh Visual Object Tracking VOT2019 Challenge Results
- 2019
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Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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| 3. |
- Li, Wenxiong, et al.
(författare)
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Can the Helium-detonation Model Explain the Observed Diversity of Type Ia Supernovae?
- 2021
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 906:2
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Tidskriftsartikel (refereegranskat)abstract
- We study a sample of 16 Type Ia supernovae (SNe Ia) having both spectroscopic and photometric observations within 2-3 days after the first light. The early B - V colors of such a sample tend to show a continuous distribution. For objects with normal ejecta velocity (NV), the C ii lambda 6580 feature is always visible in the early spectra, while it is absent or very weak in the high-velocity (HV) counterpart. Moreover, the velocities of the detached high-velocity features (HVFs) of the Ca II near-IR triplet (CaIR3) above the photosphere are found to be much higher in HV objects than in NV objects, with typical values exceeding 30,000 km s(-1) at 2-3 days. We further analyze the relation between the velocity shift of late-time [Fe II] lines (v([Fe II])) and host galaxy mass. We find that all HV objects have redshifted v([Fe II]), while NV objects have both blue- and redshifted v([Fe II]). It is interesting to point out that the objects with redshifted v([Fe II]) are all located in massive galaxies, implying that HV and a portion of NV objects may have similar progenitor metallicities and explosion mechanisms. We propose that, with a geometric/projected effect, the He-detonation model may account for the similarity in birthplace environment and the differences seen in some SNe Ia, including B - V colors, C II features, CaIR3 HVFs at early times, and v([Fe II]) in the nebular phase. Nevertheless, some features predicted by He-detonation simulation, such as the rapidly decreasing light curve, deviate from the observations, and some NV objects with blueshifted nebular v([Fe II]) may involve other explosion mechanisms.
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| 4. |
- Baek, Iljoo, et al.
(författare)
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FT-DeepNets: Fault-Tolerant Convolutional Neural Networks with Kernel-based Duplication
- 2022
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Ingår i: 2022 IEEE WINTER CONFERENCE ON APPLICATIONS OF COMPUTER VISION (WACV 2022). - : IEEE COMPUTER SOC. - 9781665409155 - 9781665409162 ; , s. 1878-1887
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Konferensbidrag (refereegranskat)abstract
- Deep neural network (deepnet) applications play a crucial role in safety-critical systems such as autonomous vehicles (AVs). An AV must drive safely towards its destination, avoiding obstacles, and respond quickly when the vehicle must stop. Any transient errors in software calculations or hardware memory in these deepnet applications can potentially lead to dramatically incorrect results. Therefore, assessing and mitigating any transient errors and providing robust results are important for safety-critical systems. Previous research on this subject focused on detecting errors and then recovering from the errors by re-running the network. Other approaches were based on the extent of full network duplication such as the ensemble learning-based approach to boost system fault-tolerance by leveraging each models advantages. However, it is hard to detect errors in a deep neural network, and the computational overhead of full redundancy can be substantial. We first study the impact of the error types and locations in deepnets. We next focus on selecting which part should be duplicated using multiple ranking methods to measure the order of importance among neurons. We find that the duplication overhead for computation and memory is a tradeoff between algorithmic performance and robustness. To achieve higher robustness with less system overhead, we present two error protection mechanisms that only duplicate parts of the network from critical neurons. Finally, we substantiate the practical feasibility of our approach and evaluate the improvement in the accuracy of a deepnet in the presence of errors. We demonstrate these results using a case study with real-world applications on an Nvidia GeForce RTX 2070Ti GPU and an Nvidia Xavier embedded platform used by automotive OEMs.
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| 5. |
- Chen, Yu, 1990, et al.
(författare)
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Genome-scale modeling for Bacillus coagulans to understand the metabolic characteristics
- 2020
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 117:11, s. 3545-3558
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Tidskriftsartikel (refereegranskat)abstract
- Lactic acid is widely used in many industries, especially in the production of poly-lactic acid. Bacillus coagulans is a promising lactic acid producer in industrial fermentation due to its thermophilic property. In this study, we developed the first genome-scale metabolic model (GEM) of B. coagulans iBag597, together with an enzyme-constrained model ec-iBag597. We measured strain-specific biomass composition and integrated the data into a biomass equation. Then, we validated iBag597 against experimental data generated in this study, including amino acid requirements and carbon source utilization, showing that simulations were generally consistent with the experimental results. Subsequently, we carried out chemostats to investigate the effects of specific growth rate and culture pH on metabolism of B. coagulans. Meanwhile, we used iBag597 to estimate the intracellular metabolic fluxes for those conditions. The results showed that B. coagulans was capable of generating ATP via multiple pathways, and switched among them in response to various conditions. With ec-iBag597, we estimated the protein cost and protein efficiency for each ATP-producing pathway to investigate the switches. Our models pave the way for systems biology of B. coagulans, and our findings suggest that maintaining a proper growth rate and selecting an optimal pH are beneficial for lactate fermentation.
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| 6. |
- Chen, Zhihao, et al.
(författare)
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Effect of Lifestyle on the Adoption of Mobile Services
- 2012
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Ingår i: The eleventh Wuhan international conference on e-business. - : Alfred University. - 9780980051056 ; , s. 390-397
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Konferensbidrag (refereegranskat)abstract
- Although mobile services have gained huge potential market in recent years, the adoption of mobile services has been far slower than expected. Many scholars put forward mobile services adoption models to explore the causes of low adoption of mobile services. But few researchers have explained why different types of services differ in terms of popularity from the view of lifestyle. The authors attempt to explain the adoption of various mobile services in the view of lifestyle through descriptive analysis and ANOVE analysis in China. And the conclusions are as follows: 1) the adoption of different types of mobile services varies with different groups of users, because 2) different groups of users often have their own lifestyles (e.g., new life consciousness, arbitrary consciousness, financial consciousness, etc.), 3) which can significantly affect their intention to adopt various mobile services.
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| 7. |
- Fiore, Achille, et al.
(författare)
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Detailed spectrophotometric analysis of the superluminous and fast evolving SN 2019neq
- 2024
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Ingår i: Monthly notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 527:3, s. 6473-6494
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Tidskriftsartikel (refereegranskat)abstract
- SN 2019neq was a very fast evolving superluminous supernova. At a redshift z = 0.1059, its peak absolute magnitude was −21.5 ± 0.2 mag in g band. In this work, we present data and analysis from an extensive spectrophotometric follow-up campaign using multiple observational facilities. Thanks to a nebular spectrum of SN 2019neq, we investigated some of the properties of the host galaxy at the location of SN 2019neq and found that its metallicity and specific star formation rate are in a good agreement with those usually measured for SLSNe-I hosts. We then discuss the plausibility of the magnetar and the circumstellar interaction scenarios to explain the observed light curves, and interpret a nebular spectrum of SN 2019neq using published SUMO radiative-transfer models. The results of our analysis suggest that the spin-down radiation of a millisecond magnetar with a magnetic field B ≃ 6×1014 G could boost the luminosity of SN 2019neq.
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| 8. |
- Gao, Hongkai, et al.
(författare)
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Stepwise modeling and the importance of internal variables validation to test model realism in a data scarce glacier basin
- 2020
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 591
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Tidskriftsartikel (refereegranskat)abstract
- Model realism is of vital importance in science of hydrology, in terms of realistic representation of hydrological processes and reliability of future prediction. Here, we employed a stepwise modeling approach that leverages flexible model structures and multi-source observations for robust streamflow simulation and internal variables validation with improved model realism. This framework is demonstrated in Yigong Zangbu River (YZR) basin, a data scarce glacier basin in the upper Brahmaputra River. We designed six experiments (Exp1–6) to use modeling as a tool to understand hydrological processes in this remote cold basin with extremely high altitude. In Exp1, we started with a distributed rainfall-runoff model (FLEXD) - representing the case that snow and glacier processes were ignored. Then, we stepwisely added snow and glacier processes into FLEXD, denoted as FLEXD-S (Exp2) and FLEXD-SG (Exp3), respectively, and such improvement of model structure led to significantly improved streamflow estimates. To explore the impact of different precipitation forcing on model performance, FLEXD-SG was driven by Theissen average (Exp3) and three individual stations’ precipitation (Exp4–6). The model realism was tested by observed hydrograph, snow cover area (SCA) and glacier mass balance (GMB). Results showed that a robust and realistic hydrological modeling system was achieved in Exp6. In this modeling study, we learned that: 1) stepwise modeling is effective in investigating catchment behavior, and snow and glacier melting are the dominant hydrological processes in the YZR basin; 2) internal variables validation is beneficial to test model realism in data scarce basin; 3) the FLEXD-SG model calibrated by only one year hydrograph is sufficient to reproduce snow and glacier variations; 4) precipitation of a single station as forcing data could outperform Theissen average; 5) based on the well tested model configuration in Exp6, we analyzed simulated results, and reconstructed the long term hydrography (1961–2013), to support the potential competence for decision making on water resources management in practice. The proposed framework may significantly improve our skills in hydrological modeling over data-poor regions.
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| 9. |
- Gao, Shang, 1982-, et al.
(författare)
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An exploratory study on lifestyles and the adoption of mobile services in China
- 2012
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Ingår i: Proceedings of the 10th International Conference on Advances in Mobile Computing & Multimedia. - New York : Association for Computing Machinery (ACM). - 9781450313070 ; , s. 249-252
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Konferensbidrag (refereegranskat)abstract
- This study examines the relationship between the lifestyles of Chinese consumers and the adoption of mobile services. Based on a sample from 313 respondents from the biggest city in central China, the results show that consumers with different lifestyles have different preferences over a number of identified mobile services. It is found that there are some lifestyle factors, such as the investment consciousness and the financial contentment consciousness, having significant negative impact on the adoption of office/learning tools on mobile devices. Furthermore, Chinese consumers are clustered into four lifestyle segments by two dimensions: the quality-awareness fashionable dimension and the economical dimension. The findings demonstrate that the quality-awareness fashionable dimension has stronger impact than the economical dimension toward the adoption of all the five types of mobile services. © 2012 ACM.
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| 10. |
- Gao, Shang, 1982-, et al.
(författare)
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Lifestyles and mobile services adoption in China
- 2014
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Ingår i: International Journal of E-Business Research. - : IGI Global. - 1548-1131 .- 1548-114X. ; 10:3, s. 36-53
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Tidskriftsartikel (refereegranskat)abstract
- Along with the popularity of mobile devices and advances in wireless technology, mobile services have become more and more prevalent. To the best of knowledge, despite the potential importance of lifestyle, little research has been performed on the effect of various lifestyle factors on mobileservices diffusion, particularly in the Chinese context. This study examines the relationship between the lifestyles of Chinese consumers and the adoption of mobile services. Based on a sample of 313 respondents from the biggest city in central China, one can show that consumers with different lifestyles have different preferences related to a number of the identified mobile services. Furthermore, Chinese consumers are clustered into four lifestyle segments by two dimensions: the quality-awareness fashionable dimension and the economical dimension. The findings demonstrate that the quality-awareness fashionable dimension has stronger impact than the economical dimension toward the adoption of all the five types of mobile services.
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