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A search for double-peaked narrow emission line galaxies and AGNs in the LAMOST DR1 认领 引用 被引量：6
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作者 Zhi-Xin Shi A-Li Luo +15 位作者 Georges Comte Xiao-Yan Chen Peng Wei Yong-Heng Zhao Fu-Chao Wu Yan-Xia Zhang Shi-Yin Shen Ming Yang Hong Wu Xue-Bing Wu Hao-Tong Zhang Ya-Juan Lei Jian-Nan Zhang Ting-Gui Wang Ge Jin Yong Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第10期1234-1250,共17页
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope （LAMOST） has released more than two million spectra, which provide the opportunity to search for double-peaked narrow emission line （NEL） galaxies and ... The Large Sky Area Multi-Object Fiber Spectroscopic Telescope （LAMOST） has released more than two million spectra, which provide the opportunity to search for double-peaked narrow emission line （NEL） galaxies and active galactic nuclei （AGNs）. The double-peaked narrow-line profiles can be well modeled by two velocity components, respectively blueshifted and redshifted with respect to the sys- temic recession velocity. This paper presents 20 double-peaked NEL galaxies and AGNs found from LAMOST DR1 using a search method based on a multi-Gaussian fit of the narrow emission lines. Among them, ten have already been published by other authors, either listed as genuine double-peaked NEL objects or as asymmetric NEL objects, and the remaining ten are original discoveries. We discuss some pos- sible origins for the double-peaked narrow-line features, such as interaction between jet and narrow line regions, interaction with companion galaxies, and black hole bina- ries. Spatially resolved optical imaging and/or follow-up observations in other spectral bands are needed to further discuss the physical mechanisms at work. 展开更多
关键词 galaxies emission lines -- quasars emission lines -- methods dataanalysis
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Big data assessment on the operating characteristics of on-line taxis and thoughts on relevant policies 认领 引用 被引量：2
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作者 Sun Chao Chen Xiaohong +1 位作者 Zhang H.Michael Chen Shu 《Journal of Southeast University(English Edition)》 EI CAS 2018年第3期394-401,共8页
A double-dimensional big data assessment method on the characteristics of on-line taxi traffic operation is proposed to provide a scientific basis for carrying out the taxi industry reform and standardizing the on-lin... A double-dimensional big data assessment method on the characteristics of on-line taxi traffic operation is proposed to provide a scientific basis for carrying out the taxi industry reform and standardizing the on-line taxi hailing management work. Taking Shenzhen as an example, multi- source data such as on-line taxi license plate data, plate identification data and taxi （including on-line taxis） operation data are combined with the results of the stated preference （SP） survey on taxi operating characteristics to assess the overall operation characteristics of on-line taxis. The results show that the current on-line taxis in Shenzhen can be divided into three categories, that is, full-time on-line taxis, non- active on-line taxis and part-time on-line taxis, accounting for 4%, 55%, and 41%, respectively, of the total quantity. In terms of the characteristics of space-time operations, full-time on-line taxis have similar operating characteristics as those of traditional taxis; the operation of non-active on-line taxis and part-time on-line taxis coincides with commuting requirements during morning and evening peak hours. However, part-time on-line taxis operate for a much longer time period at night. Due to the convenient hailing and favorable price, on-line taxis have a significant impact on trip modes of citizens; and the substitution eflbct of on-line taxis on traditional buses and cruising taxis is obvious. It is beneficial for helping the government departments to objectively understand the development law of the on-line taxi industry and providing decision reference for the formulation of relevant management policies during the critical development stage of on-line taxi industry. 展开更多
关键词 on-line taxi trip characteristics license plateidentification stated preference （ SP ） survey big dataanalysis policy assessment
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Evolution of isolated G-band bright points: size, intensity and velocity 认领 引用 被引量：3
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作者 Yun-Fei Yang Jia-Ben Lin +3 位作者 Song Feng Kai-Fan Ji Hui Deng Feng Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第6期741-752,共12页
We study the evolution pattern of isolated G-band bright points （GBPs） in terms of their size, intensity and velocity. Using a high resolution image sequence taken with the Hinode/Solar Optical Telescope （SOT）, we... We study the evolution pattern of isolated G-band bright points （GBPs） in terms of their size, intensity and velocity. Using a high resolution image sequence taken with the Hinode/Solar Optical Telescope （SOT）, we detect GBPs in each image by the Laplacian and Morphological Dilation algorithm, and track their evolutions by a 26-adjacent method in a three-dimensional space-time cube. For quantifying the evolution, we propose a quantification method based on lifetime normalization which aligns the different lifetimes to common stages. The quantification results show that, on average, the diameter of isolated GBPs changes from 166 to 173 km, then down to 165 km; the maximum intensity contrast changes from 1.012 to 1.027, then down to 1.011; however, the velocity changes from 1.709 to 1.593 km s-1, then up to 1.703 km s-i. The results indicate that the evolution follows a pattern such that the GBP is small, faint and fast-moving at the birth stage, becomes big, bright and slow-moving at the middle stage, then gets small, faint and fast-moving at the decay stage until disappearance. Although the differences are very small, a two-sample t-test is used to demonstrate there are significant differences in means between the distri- butions of the different stages. Furthermore, we quantify the relationship between the lifetimes of GBPs and their properties. It is found that there are positive correlations between the lifetimes and their sizes and intensities with correlation coefficients of 0.83 and 0.65, respectively; however, there is a negative correlation between the life- times and velocities with a correlation coefficient of-0.49. In summary, the longer the GBP persists, the bigger, brighter and slower it will be. 展开更多
关键词 techniques： image processing -- Sun： photosphere -- methods： dataanalysis -- methods： statistical
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Characterizing motion types of G-band bright points in the quiet Sun 认领 引用 被引量：3
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作者 Yun-Fei Yang Hui-Xue Qu +4 位作者 Kai-Fan Ji Song Feng Hui Deng Jia-Ben Lin Feng Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第4期569-582,共14页
We study the motion of G-band bright points （GBPs） in the quiet Sun to obtain the characteristics of different motion types. A high resolution image sequence taken with the Hinode/Solar Optical Telescope （SOT） is ... We study the motion of G-band bright points （GBPs） in the quiet Sun to obtain the characteristics of different motion types. A high resolution image sequence taken with the Hinode/Solar Optical Telescope （SOT） is used, and GBPs are automat- ically tracked by segmenting 3D evolutional structures in a space-time cube. After putting the GBPs that do not move during their lifetimes aside, the non-stationary GBPs are categorized into three types based on an index of their motion type. Most GBPs that move in straight or nearly straight lines are categorized as a straight mo- tion type, a few moving in rotary paths into rotary motion, and the others fall into a motion type we called erratic. The mean horizontal velocities are 2.18±0.08 km s-1, 1.63±0.09km s^-1 and 1.33±0.07 km s^-1 for straight, erratic and rotary motion types, respectively. We find that a GBP drifts at a higher and constant velocity during its whole life if it moves in a straight line. However, it has a lower and variational velocity if it moves on a rotary path. The diffusive process is ballistic-, super- and sub-diffusion for straight, erratic and rotary motion types, respectively. The corresponding diffusion index （γ） and coefficients （K） are 2.13±0.09 and 850±37km^2 s^-1, 1.82±0.07 and 331 ±24 km^2 s^-1, and 0.73±0.19 and 13±9 km^2 s^-1. In terms of direction of motion, it is homogeneous and isotropic, and usually persists between neighboring frames, no matter what motion type a GBP is classified as. 展开更多
关键词 techniques： image processing -- Sun： photosphere -- methods： dataanalysis -- methods： statistical
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Estimating Photometric Redshifts with Artificial Neural Networks and Multi-Parameters 认领 引用
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作者 Li-Li Li Yan-Xia Zhang +1 位作者 Yong-Heng Zhao Da-Wei Yang 《Chinese Journal of Astronomy and Astrophysics》 2007年第3期448-456,共9页
We calculate photometric redshifts from the Sloan Digital Sky Survey Data Release 2 （SDSS DR2） Galaxy Sample using artificial neural networks （ANNs）. Different input sets based on various parameters （e.g. magnitu... We calculate photometric redshifts from the Sloan Digital Sky Survey Data Release 2 （SDSS DR2） Galaxy Sample using artificial neural networks （ANNs）. Different input sets based on various parameters （e.g. magnitude, color index, flux information） are explored. Mainly, parameters from broadband photometry are utilized and their performances in redshift prediction are compared. While any parameter may be easily incorporated in the input, our results indicate that using the dereddened magnitudes often produces more accurate photometric redshifts than using the Petrosian magnitudes or model magnitudes as input, but the model magnitudes are superior to the Petrosian magnitudes. Also, better performance resuits when more effective parameters are used in the training set. The method is tested on a sample of 79 346 galaxies from the SDSS DR2. When using 19 parameters based on the dereddened magnitudes, the rms error in redshift estimation is σz = 0.020184. The ANN is highly competitive tool compared to the traditional template-fitting methods when a large and representative training set is available. 展开更多
关键词 galaxies fundamental parameters - techniques photometric - method dataanalysis
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Improving accuracy of age estimates for insect evidence—calibration of physiological age at emergence (k) using insect size but without “k versus size” model 认领 引用 被引量：1
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作者 Jędrzej Wydra Łukasz Smaga Szymon Matuszewski 《Forensic Sciences Research》 CSCD 2024年第1期46-51,共6页
Postmortem interval may be estimated based on the age of insect evidence collected on a death scene. Reference data that are used in such estimation frequently comprise thermal summation constant (i.e. k), which is eq... Postmortem interval may be estimated based on the age of insect evidence collected on a death scene. Reference data that are used in such estimation frequently comprise thermal summation constant (i.e. k), which is equal to the insect age upon completion of immature development expressed in accumulated degree-days or degree-hours (ADD or ADH). Essentially, k is a central point of an insect group and it may poorly represent insect evidence that is near the limits of variation for the group. Accordingly, it was postulated to calibrate k for particular insect evidence and insect size and sex were found to be useful for this purpose in some of the species. However, the calibration is only possible by using the model that correlates k with insect size. Since very few such models were published, this lack of data limits the calibration of k in forensic casework. In this article, we develop a formula that is useful for the calibration of k without the use of “k versus size” model (and related datasets). The formula uses k from the general thermal summation model for a species (with its standard error), size range for the species (retrieved from entomology literature), and size measurements for particular insect evidence. The calibration of k with the formula was validated using the Creophilus maxillosus (Coleoptera: Staphylinidae) and Necrodes littoralis (Coleoptera: Silphidae) datasets. It was particularly useful while analyzing unusually small and large insects, in case of which the formula reduced the inaccuracy of k from the general model on average by ~25 ADD in C. maxillosus and ~40 ADD in N. littoralis. We discuss the limitations and prospects of the calibration protocol that employs the formula. 展开更多
关键词 forensicentomology postmorteminterval insectage accuracy dataanalysis
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The Relationship Between Financial Reporting Standards (FRS) 139 and Audit Pricing: The Case of Malaysia 认领 引用
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作者 Najihah Marha Yaacob 《Journal of Modern Accounting and Auditing》 2013年第5期641-649,共9页
This study provides some insights for auditors to gauge the complexity of the financial statements verification process to comply with the ambiguous standard, namely, Financial Reporting Standards （FRS） 139 in Malay... This study provides some insights for auditors to gauge the complexity of the financial statements verification process to comply with the ambiguous standard, namely, Financial Reporting Standards （FRS） 139 in Malaysia. Hence, the purpose of this study is to examine the relationship between the adoption of FRS 139 and the audit fees charged to clients. The final sample consists of 1,050 finn-year observations covering the period from 2006 to 2008 from the non-financial companies listed on the Bursa Malaysia. In this study, the static panel data analysis is used to provide richer interpretation and a powerful understanding of the effect of standard adoption on audit pricing. The regression results from the random effects Generalized Least Squares （GLS） suggest that FRS 139 adoption has not significantly increased audit fees. The small number of observations for FRS 139 voluntary adoption is suspected to be the main limitation factor contributing to the insignificant result of the hypothesis. It is suggested that the limitation of small observations of FRS 139 voluntary adopters might be encountered during the period of mandatory adoption. Therefore, future research might investigate the impact of mandatory FRS 139 adoption. 展开更多
关键词 audit fees Financial Reporting Standards （FRS） 139 Malaysia financial instruments panel dataanalysis
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AI for mechanics 认领 引用
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作者 Minqiang Jiang Shizhao Wang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CSCD 2026年第1期1-2,共2页
"Artificial intelligence (AI) for Science"is,at an unprecedented speed and scale,shaping the paradigm of scientific research,accelerating innovation in technology and industry.Research on modern or contempor... "Artificial intelligence (AI) for Science"is,at an unprecedented speed and scale,shaping the paradigm of scientific research,accelerating innovation in technology and industry.Research on modern or contemporary mechanics,rooted in Galileo's"experiments-mathematics"paradigm,has embraced AI in recent years.Machine learning (ML) of data becomes crucial in the face of complex mechanical problems ranging from turbulence of fluids,failure of solids,to multiscale structural optimization. 展开更多
关键词 innovation scientificresearch dataanalysis machinelearning mechanics artificialintelligence artificial intelligence multiscale structural optimization
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Artificial Intelligence and Machine Learning for Environmental Health Study 认领 引用 被引量：1
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作者 Miao Yu Mingliang Fang +2 位作者 Zhenyu Tian Bin Wang Douglas Walker 《Environment & Health》 CAS CSCD 2025年第10期1115-1116,共2页
The complex relationship between environmental exposure and human health constitutes a major global challenge requiring innovative solutions.Artificial Intelligence(AI)and Machine Learning(ML)show exceptional strength... The complex relationship between environmental exposure and human health constitutes a major global challenge requiring innovative solutions.Artificial Intelligence(AI)and Machine Learning(ML)show exceptional strength for data analysis and pattern recognition.Applying these technologies to environmental health provides new insights to improve and advance environmental exposure assessment,health risk assessment,and related policy development.It is with great pleasure that we present this Special Issue of Environment&Health on Machine Learning and Artificial Intelligence for Environmental Health.This collection of research highlights the latest advancements and broad potential of ML and AI to empower our response to pressing and future environmental health issues. 展开更多
关键词 pattern recognitionapplying environmentalhealth data analysis patternrecognition machine learning ml show dataanalysis machinelearning environmental health
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