分类： 计算机科学 >> 计算机科学的集成理论 提交时间： 2024-12-03
摘要： Traditional recommendation systems focus on max#2;imizing user satisfaction by suggesting their favorite items. Thisuser-centric approach may lead to unfair exposure distributionamong the providers. On the contrary, a provider-centric designmight become unfair to the users. Therefore, this paper pro#2;poses a re-ranking model FairSort1to find a trade-off solutionamong user-side fairness, provider-side fairness, and personalizedrecommendations utility. Previous works habitually treat thisissue as a knapsack problem, incorporating both-side fairnessas constraints.In this paper, we adopt a novel perspective, treating eachrecommendation list as a runway rather than a knapsack. Inthis perspective, each item on the runway gains a velocity andruns within a specific time, achieving re-ranking for both-sidefairness. Meanwhile, we ensure the Minimum Utility Guaranteefor personalized recommendations by designing a Binary Searchapproach. This can provide more reliable recommendations com#2;pared to the conventional greedy strategy based on the knapsackproblem. We further broaden the applicability of FairSort,designing two versions for online and offline recommendationscenarios. Theoretical analysis and extensive experiments on real#2;world datasets indicate that FairSort can ensure more reliablepersonalized recommendations while considering fairness forboth the provider and user.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 分类： 计算机科学 >> 计算机科学的集成理论 提交时间： 2017-03-15
摘要： As the next stage of Artificial Intelligence, Brain-like Intelligent Computing will be considered as a fundamental role in the forthcoming China Brain Project. Researchers have tried to use the brain frame structure and the brain functions, aiming at developing a new generation of information theory and computational methods (such as a new generation of artificial intelligence systems). Different from the traditional information processing based on the classical physics and logics, the human brain should rely on a deeper level physics (such as quantum mechanics) to process information, generate awareness and consciousness. The project will try to exploit quantum information theory in the human cognition related information interaction and processing models. The overall research goal is: in typical information interaction scenarios (such as exploratory information access and natural language understanding), modeling the non-classical (quantum or quantum-like) experimental phenomenon, developing quantum models of cognitive behavior, and establishing a new framework of brain-like information interaction model, with the application in typical tasks for information interaction scenarios.
分类： 地球科学 >> 地球科学其他学科 提交时间： 2024-11-19 合作期刊: 《干旱区科学》
摘要： The Grain for Green project has had a substantial influence on water conservation in the Huangshui River Basin, China through afforestation and grassland restoration over the past two decades. However, a comprehensive understanding of the spatiotemporal evolution of water conservation function and its driving factors remains incomplete in this basin. In this study, we utilized the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model to examine the spatiotemporal evolution of water conservation function in the Huangshui River Basin from 2000 to 2020. Additionally, we employed the random forest model, Pearson correlation analysis, and geographical detector (Geodetector) techniques to investigate the primary factors and factor interactions affecting the spatial differentiation of water conservation function. The findings revealed several key points. First, the high-latitude northern region of the study area experienced a significant increase in water conservation over the 21-a period. Second, the Grain for Green project has played a substantial role in improving water conservation function. Third, precipitation, plant available water content (PAWC), grassland, gross domestic product (GDP), and forest land were primary factors influencing the water conservation function. Finally, the spatial differentiation of water conservation function was determined by the interactions among geographical conditions, climatic factors, vegetation biophysical factors, and socio-economic factors. The findings have significant implications for advancing ecological protection and restoration initiatives, enhancing regional water supply capabilities, and safeguarding ecosystem health and stability in the Huangshui River Basin.
分类： 物理学 >> 核物理学 提交时间： 2023-06-26
摘要： The possible exotic nuclear properties in the neutron-rich Ca, Ni, Zr, and Sn isotopes are examined with the continuum Skyrme HartreeFockBogoliubov theory in the framework of the Green's function method. The pairing correlation, the couplings with the continuum, and the blocking effects for the unpaired nucleon in odd-A nuclei are properly treated. The Skyrme interaction SLy4 is adopted for the ph channel and the density-dependent interaction is adopted for the pp channel, which well reproduce the experimental two- neutron separation energies S2n and one-neutron separation energies Sn. It is found that the criterion Sn > 0 predicts a neutron drip line with neutron numbers far smaller than those for S2n > 0. Owing to the unpaired odd neutron, the neutron pairing energies Epair in odd-A nuclei are far lower than those in the neighboring even-even nuclei. By investigating the single-particle structures, the possible halo structures in the neutron#2; rich Ca, Ni, and Sn isotopes are predicted, where sharp increases in the root-mean-square (rms) radii with signifificant deviations from the traditional r A 1/3 rule and diffuse spatial density distributions are observed. Analyzing the contributions of various partial waves to the total neutron density lj (r)/(r) reveals that the orbitals located around the Fermi surfaceparticularly those with small angular momentasignifificantly affect the extended nuclear density and large rms radii. The number of neutrons N (N0) occupying above the Fermi surface n (continuum threshold) is discussed, whose evolution as a function of the mass number A in each isotope is consistent with that of the pairing energy, supporting the key role of the pairing correlation in halo phenomena.
分类： 天文学 >> 天文仪器与技术 提交时间： 2016-04-27
摘要： AstroCloud is a cyber-Infrastructure for Astronomy Research initiated by Chinese Virtual Observatory (China-VO) under funding support from NDRC (Na- tional Development and Reform commission) and CAS (Chinese Academy of Sci- ences). Tasks such as proposal submission, proposal peer-review, data archiving, data quality control, data release and open access, Cloud based data processing and analyz- ing, will be all supported on the platform. It will act as a full lifecycle management system for astronomical data and telescopes. Achievements from international Virtual Observatories and Cloud Computing are adopted heavily. In this paper, backgrounds of the project, key features of the system, and latest progresses are introduced.
分类： 心理学 >> 心理学其他学科 提交时间： 2023-01-02 合作期刊: 《Sports & Social Psychology》
摘要： To investigate the effects of the 6-weeks progressive core stability training on dynamic balance and agility in male college students specialized in badminton. 65 college students majoring in physical education are randomly divided into an experimental group (for the 6-week progressive core stability training) and a control group (for the 6-week regular physical training). The duration, frequency and intensity of physical training are the same in both groups. The results indicates that after the intervention: (1) The results and overall scores of the 8 directions of SEBT in the experimental group are better than those before the intervention, but there are no differences in the all SEBT results in all directions on the left and right parts. (2) The test results and overall scores of the left leg supported under the experimental group were better than those of the control group in all directions except the results in the anterior and external directions, and the results in the external and anterior directions under the right leg support. (3) Only the reach distance of SEBT under left and right leg support in the control group significantly increases in the external direction compared with that before the intervention. (4) No significant change in agility was observed in both groups. Conclusions: Progressive core stability training can significantly improve the dynamic balance of male college students specialized in badminton among those majoring in physical education, promote the balanced development in dynamic equilibrium on the left and right parts, but it cannot significantly improve their agility.
分类： 天文学 >> 天文学 提交时间： 2016-11-15
摘要： With the development of network and the World Wide Web (WWW), the Internet has been growing and changing dramatically. More and more on-line database systems and different kinds of services are available for astronomy research. How to help users find their way through the jungle of information services becomes an important challenge. Although astronomers have been aware of the importance of interoperability and introduced the concept of Virtual Observatory as a uniform environment for future astronomical on-line resources and services, transparent access to heterogeneous on-line information is still difficult.
分类： 物理学 >> 核物理学 提交时间： 2016-09-13
摘要： Investigating the CKM matrix in different parametrization schemes, it is noticed that those schemes can be divided into a few groups where the sine values of the CP phase for each group are approximately equal. Using those relations, several approximate equalities among the elements of CKM matrix are established. Assuming them to be exact, there are infinite numbers of solutions and by choosing special values for the free parameters in those solutions, several textures presented in literature are obtained. The case can also be generalized to the PMNS matrix for the lepton sector. In parallel, several mixing textures are also derived by using presumed symmetries, amazingly, some of their forms are the same as what we obtained, but not all. It hints existence of a hidden symmetry which is broken in the practical world. The nature makes its own selection on the underlying symmetry and the way to break it, while we just guess what it is.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-08
Dong, SJ [Dong, Sujuan][ 1,2 ]
Wan, YY [Wan, Yangyang][ 1,2 ]
Wang, YL [Wang, Yaling][ 1,2 ]
Yang, Y [Yang, Yin][ 1,2 ]
Wang, YH [Wang, Yahui][ 1,2 ]
Zhang, XY [Zhang, Xinyu][ 1,2 ]
Cao, HQ [Cao, Huanqi][ 1,2 ]
Qin, WJ [Qin, Wenjing][ 1,2 ]
Yang, LY [Yang, Liying][ 1,2 ]
Yao, C [Yao, Cong][ 3 ]
摘要： We report a doping method to enhance the performance of solution processed planar heterojunction perovskite solar cells. By doping a small percentage (3 wt%) of polyethylenimine (PEI) as additive into the PCBM electron transport layer of an inverted perovskite solar cell, which led to significant enhancements of power conversion efficiency from (5.9 ` 0.2) % to (10.4 ` 0.2) %. The AFM images show that the PEI doped PCBM layer can help to form a high quality, homogeneous and compact electron transporting layer on the rough CH3NH3PbI3 layer, which results in enhanced hole blocking ability and reduced leakage current at the interfaces between the CH3NH3PbI3, PCBM films and the top Al electrode. Organic field-effect transistors (OFETs) measurements reveal that the addition of 1–3 wt% PEI into PCBM layer can improve device performance without any negative effect on the electron transport property of PCBM. Steady-state PL analysis shows that the electron-rich PEI may also act as an effective interfacial modifier to passivate the trap states at the perovskite surface or crystal boundaries and to avoid the undesired charge recombination often observed in perovskite solar cells. PEI will also improve performance as a cathode interfacial modifier because the PCE of the device with PEI deposited between PCBM and Al is superior to the device without PEI. This work demonstrated that amine- containing polymer materials can be used as an efficient dual functional additive in perovskite solar cells. This study provides an efficient way of developing highly efficient CH3NH3PbI3-based perovskite solar cells.
分类： 地球科学 >> 地理学 提交时间： 2023-02-15 合作期刊: 《干旱区科学》
摘要： Investigating the effect of geocells on the erosion and deposition distribution of ephemeral gullies in the black soil area of Northeast China can provide a scientific basis for the allocation of soil and water conservation measures in ephemeral gullies. In this study, an artificial simulated confluence test and stereoscopic photogrammetry were used to analyze the distribution characteristics of erosion and deposition in ephemeral gullies protected by geocells and the effect of different confluence flows on the erosion process of ephemeral gullies. Results showed that when the confluence flow was larger, the effect of geocell was more evident, and the protection against ephemeral gully erosion was stronger. When the confluence flow rates were 0.6, 1.8, 2.4, and 3.0 m3/h, ephemeral gully erosion decreased by 37.84%, 26.09%, 21.40%, and 35.45%. When the confluence flow rates were 2.4 and 3.0 m3/h, the average sediment yield rate of the ephemeral gully was close to 2.14 kg/(m2min), and the protective effect of ephemeral gully erosion was enhanced. When the flow rate was higher, the surface fracture of the ephemeral gully was more serious. With an increase in confluence flow rate, the ratio of erosion to deposition increased gradually, the erosion area of ephemeral gullies was expanded, and erosion depth changed minimally. In conclusion, geocell measures changed erosion patterns by altering the rill erosion/deposition ratio, converting erosion from rill erosion to sheet erosion.
分类： 生物学 >> 生态学 提交时间： 2022-06-20 合作期刊: 《干旱区科学》
摘要： Abstract: A knowledge of the tree-ring stable nitrogen isotope ratio (15N) can deepen our understanding of forest ecosystem dynamics by indicating the long-term availability, cycling and sources of nitrogen (N). However, the radial mobility of N blurs the interannual variations in the long-term N records. Previous studies of the chemical extraction of tree rings before analysis had produced inconsistent results and it is still unclear whether it is necessary to pre-treat wood samples from specific tree species to remove soluble N compounds before determining the 15N values. We compared the effects of pre-treatment with organic solvents and hot ultrapure water on the N concentration and 15N of tree rings from endemic Qinghai spruce (Picea crassifolia) growing in the interior of the central Qilian Mountains, China, during the last 60 a. We assessed the effects of different preparation protocols on the removal of the labile N compounds and investigated the need to pre-treat wood samples before determining the 15N values of tree rings. Increasing trends of the tree-ring N concentration were consistently observed in both the extracted and unextracted wood samples. The total N removed by extraction with organic solvents was about 17.60%, with a significantly higher amount in the sapwood section (P<0.01). The 15N values of tree rings decreased consistently from 1960 to 2019 in both the extracted and unextracted wood samples. Extraction with organic solvents increased the 15N values markedly by about 5.2 and reduced the variations in the 15N series. However, extraction with hot ultrapure water had little effect, with only a slight decrease in the 15N values of about 0.5. Our results showed that the radial pattern in the inter-ring movement of N in Qinghai spruce was not minimized by extraction with either organic solvents or hot ultrapure water. It is unnecessary to conduct hot ultrapure water extraction for the wood samples from Qinghai spruce because of its negligible effect on the removal of the labile N. The 15N variation trend of tree rings in the unextracted wood samples was not influenced by the heartwoodsapwood transition zone. We suggest that the 15N values of the unextracted wood samples of the climate-sensitive Qinghai spruce could be used to explore the ecophysiological dynamics while focusing on the long-term variations.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-11-10
分类： 天文学 >> 天文学 提交时间： 2016-11-16
Chenzhou Cui
Ce Yu
Jian Xiao
Boliang He
Changhua Li
Dongwei Fan
Chuanjun Wang
Zhi Hong
Shanshan Li
Linying Mi
Wanghui Wan1
Zihuang Cao
Jiawei Wang
Shucheng Yin
Yufeng Fan
Jianguo Wang
Sisi Yang
Yin Ling
Hailong Zhang
Junyi Chen
摘要： As the cyber-infrastructure for Astronomical research from Chinese Virtual Observatory (China-VO) project, AstroCloud has been archived solid progresses during the last one year. Proposal management system and data access system are redesigned. Several new sub-systems are developed, including China-VO PaperData, AstroCloud Statics and Public channel. More data sets and application environments are integrated into the platform. LAMOST DR1, the largest astronomical spectrum archive was released to the public using the platform. The latest progresses will be introduced.
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