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1. chinaXiv:202205.00169 [pdf]

图像的视觉感知质量评价新概念 ----单幅图像视觉感知质量评价和独立图像间的视觉感知质量比较

祝锐; 刘玉红; 王体春; 谢正祥
Subjects: Biology >> Biomedical Laboratory Science

直至现在,图像质量评价都没有涉及色彩问题。图像质量评价的文献多是评价图像质量(在压缩、传输等图像处理过程中)的变差(降质)程度。平面图像是一种二维的亮度分布。亮度是图像视觉质量的核心参量,没有亮度就没有图像,也就没有论及图像质量的可能。本文提出了三个层次的图像视觉感知质量评价(VPQA)指标:单幅单参数图像质量评价(SS_IQA),单幅五参数精细图像质量评价(SF_IQA),考虑彩色保真性的增强图像质量评价(CF_IQA)。横向论,可分为单幅的图像质量评价(SIQA),多幅图像质量比较,图像增强中的质量评价等三个方面。图像视觉质量评价是智能最佳化图像增强的不可或缺的工具。

submitted time 2022-05-26 Hits31Downloads15 Comment 0

2. chinaXiv:202205.00168 [pdf]

多级属性Q矩阵的验证与估计

秦春影; 喻晓锋
Subjects: Psychology >> Psychological Measurement

多级属性是将诊断测验中传统的二值(即两种水平,通常定义为0和1)属性定义为多值 (多个水平可以为0,1,…),它不但可以描述学生对于知识属性是否掌握,而且可以描述学生在属性上的掌握程度,这样使得诊断测验能提供给被试更丰富的知识掌握详情。本文将适用于二级属性Q矩阵的统计量 (S 统计量)拓展到多级属性下的Q矩阵验证和估计,在两种常见的条件下,设计了两种估计算法:联合估计算法和在线估计算法。模拟实验结果表明:联合估计算法适用于对专家界定的初始Q矩阵进行验证,当初始Q矩阵中包含较少的错误时,通过联合估计算法有很大可能恢复正确的Q矩阵;在线估计算法适用于对“新项目”进行属性向量和项目参数的在线标定,基于一定数量的“基础项目”,在线估计算法对于新项目的估计也能达到较满意的成功率。实证数据分析则进一步展示了该方法的使用。

submitted time 2022-05-26 Hits106Downloads48 Comment 0

3. chinaXiv:202205.00167 [pdf]

一体化促进联结记忆的作用机制:熟悉性和回想加工

刘泽军; 刘伟
Subjects: Psychology >> Cognitive Psychology

当两个或两个以上项目进行一体化编码时,熟悉性也能够支持联结再认,这一观点已经得到大量研究证据的支持。然而,关于一体化如何影响联结再认和构成联结的单个项目再认仍存在分歧。通过回顾现有研究发现:(1)一体化一致性是调节一体化与联结再认关系的重要因素;(2)认知资源有限和新/旧词语义相关性是影响一体化对项目再认作用的重要因素;(3)一体化的发生机制存在 “项目假说”、“图式假说”以及“精细加工假说”三种可能的理论解释。未来研究不仅需要控制一体化一致性,还可以比较不同一体化方式的作用大小以及探索一体化效应的毕生发展规律。

submitted time 2022-05-26 Hits76Downloads38 Comment 0

4. chinaXiv:202205.00165 [pdf]

Transport mechanism of eroded sediment particles under freeze-thaw and runoff conditions

WANG Tian
Subjects: Geosciences >> Geography

Abstract: Hydraulic erosion associated with seasonal freeze-thaw cycles is one of the most predominant factors, which drives soil stripping and transportation. In this study, indoor simulated meltwater erosion experiments were used to investigate the sorting characteristics and transport mechanism of sediment particles under different freeze-thaw conditions (unfrozen, shallow-thawed, and frozen slopes) and runoff rates (1, 2, and 4 L/min). Results showed that the order of sediment particle contents was silt>sand>clay during erosion process on unfrozen, shallow-thawed, and frozen slopes. Compared with original soils, clay and silt were lost, and sand was deposited. On unfrozen and shallow-thawed slopes, the change of runoff rate had a significant impact on the enrichment of clay, silt, and sand particles. In this study, the sediment particles transported in the form of suspension/saltation were 83.58%–86.54% on unfrozen slopes, 69.24%–84.89% on shallow-thawed slopes, and 83.75%–87.44% on frozen slopes. Moreover, sediment particles smaller than 0.027 mm were preferentially transported. On shallow-thawed slope, relative contribution percentage of suspension/saltation sediment particles gradually increased with the increase in runoff rate, and an opposite trend occurred on unfrozen and frozen slopes. At the same runoff rate, freeze-thaw process had a significant impact on the relative contribution percentage of sediment particle transport via suspension/saltation and rolling during erosion process. The research results provide an improved transport mechanism under freeze-thaw condition for steep loessal slopes.

submitted time 2022-05-25 Cooperative journals:《Journal of Arid Land》 Hits76Downloads39 Comment 0

5. chinaXiv:202205.00166 [pdf]

Wind regimes and associated sand dune types in the hinterland of the Badain Jaran Desert, China

MENG Nan; WANG Nai'ang; ZHAO Liqiang; NIU Zhenmin
Subjects: Geosciences >> Geography

Abstract: Wind controls the formation and development of sand dunes. Therefore, understanding the wind regimes is necessary in sand dune research. In this study, we combined the wind data from 2017 to 2019 at four meteorological stations (Cherigele and Wuertabulage stations in the lake basins, and Yikeri and Sumujilin stations on the top of sand dunes) in the hinterland of the Badain Jaran Desert in China, with high resolution Google Earth images to analyze the correlation between the wind energy environments and dune morphology. The results of data analysis indicated that both the wind direction and sand drift intensity exhibited notable spatial and temporal variations. The highest level of wind activity was observed in spring. Northwesterly and northeasterly winds were the dominant in the Badain Jaran Desert. At the Cherigele, Wuertabulage, and Yikeri stations, the drift potential (DP) was below 200.00 vector units (VU). The wind energy environments in most areas could be classified as low-energy environments. The resultant drift direction differed at different stations and in different seasons, but the overall direction was mainly the southeast. The resultant drift potential (RDP)/DP ratio was greater than 0.30 in most parts of the study area, suggesting that the wind regimes mainly exhibited unimodal or bimodal characteristics. Differences between the thermodynamic properties and the unique landscape settings of lakes and sand dunes could alter the local circulation and intensify the complexity of the wind regimes. The wind regimes were weaker in the lake basins than on the top of sand dunes. Transverse dunes were the most dominant types of sand dunes in the study area, and the wind regimes at most stations were consistent with sand dune types. Wind was thus the main dynamic factor affecting the formation of sand dunes in the Badain Jaran Desert BJD. The results of this study are important for understanding the relationship between the wind regimes and aeolian landforms of the dune field in the deserts.

submitted time 2022-05-25 Cooperative journals:《Journal of Arid Land》 Hits64Downloads32 Comment 0

6. chinaXiv:202205.00164 [pdf]

基于纳米压痕法的富Sn相应力-应变关系的研究

刘志高; 侯斌; 刘天寒; 秦红波
Subjects: Mechanical Engineering >> Machinofacture Technique and Equipment

在电子封装领域中,所用的无铅钎料主要是二元或者三元Sn基共晶或近共晶合金,其基体相为富Sn相。为得到富Sn相的力学性能及应力-应变关系,由纳米压痕试验测试获得了富Sn相的弹性模量与硬度,并得到载荷-位移曲线。采用有限元反演分析的方法确定了富Sn相的特征应力和特征应变,并由量纲函数确定应变强化指数。将特征应力和特征应变强化指数等参数代入幂强化模型中,计算得到富Sn相的屈服强度为31.51 MPa,并最终确定富Sn相的应力-应变关系函数表达式。

submitted time 2022-05-25 Cooperative journals:《桂林电子科技大学学报》 Hits84Downloads38 Comment 0

7. chinaXiv:202201.00058 [pdf]

科研诚信外部规范视域:国家科技计划项目随机抽检的现实驱动与学理逻辑

刘胜利
Subjects: Management Science >> Science ology and Management

为从本质、源头和原理层面深化各方对“国家科技计划项目抽检”的经验认知,本研究基于科研诚信外部规范的理论视角,对其制度化实践的现实驱动和学理依据进行了系统整理和阐述,并从四个方面提出了建设性意见,以之促进形成群策群力、理性决策的制度实践氛围。论述对于“破四唯、五唯”时代科研管理实践和科学政策学理论建构,具有基础性参考意义。

submitted time 2022-05-23 Hits10017Downloads559 Comment 0

8. chinaXiv:202205.00163 [pdf]

科技革命、颠覆性技术与智慧农业

胡瑞法; 刘万嘉文
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture

本文首先阐述了科技革命的概念与满足条件,提出并分析了内生及外生农业颠覆性技术及其差异,特别是提出了跨界技术的概念并论证了其对农业科技进步的外生影响。然后分析了作为跨界技术的集大成者——智慧农业技术的特点,智慧农业对传统农业生产技术与生产方式的替代以及智慧农业与农村经济转型的关系。在此基础上讨论了中国智慧农业发展所面临的问题。最后有针对性地提出了促进颠覆性技术创新和智慧农业发展的政策建议,包括加强关键颠覆性核心技术研发、改革现有的农业高等教育体系、推动跨界技术的农业产业化研发以及在高标准农田及规模化养殖场实施智慧农业生产等。

submitted time 2022-05-23 Cooperative journals:《智慧农业(中英文)》 Hits191Downloads106 Comment 0

9. chinaXiv:202205.00104 [pdf]

基于科研产出关联的大科学装置集群规划布局分析方法研究

冯凌子; 张汝昊; 冯凯悦; 袁军鹏
Subjects: Library Science,Information Science >> Information Science

[目的] 大科学装置对促进重大科技成果产出具有重要作用,其集群化发展协同创新效应不 断引领区域产业创新发展。为了使大装置更好地发挥协同效应,需要更好地进行大装置规划布局。 [方法] 本研究从科研成果入手,提出一种通用的分析框架,可用于辅助分析大科学装置间学科层面的关联程度,作为以需求驱动规划的补充。以广东松山湖科学城为例,收集已有大装置(散裂中子源与同步辐射光源)与规划布局的大装置 Y 在国际上同类型装置的论文数据, 分析其学科层面的内在关联,用以辅助判断规划布局的装置与已有装置的匹配关联程度。 [结果] 已有装置(散裂中子源与同步辐射光源)关联度高,存在可能的互补关系,大装置 Y 与已有装置关联度则较低,如要布局建议还需要进一步专家论证。 [局限]本研究主要从装置产出成果来量化装置间联系,只可为决策者提供一种客观的数据视角和辅助参考,在大科学装置集群的规划方面,更重要的是国家整体的规划和区域对大科学装置的需求,本方法需要融合大科学装置的内在原理、运作流程以及专家知识,才可在规划布局中发挥真正的作用。 [结论] 该方法一定程度上能为大装置规划布局提供前瞻性的定量化参考,从而为大装置群的功能协调与未来发展提供预见性、全局性的优化方案。

submitted time 2022-05-22 Hits2868Downloads147 Comment 0

10. chinaXiv:202205.00143 [pdf]

水葱和香蒲叶经济性状对模拟增温和 CO2浓度倍增的响应

余洪艳; 孙梅; 冯春慧; 许俊萍; 陈弘毅; 刘振亚
Subjects: Biology >> Botany >> Applied botany

气候变化是国际社会共同关注的环境问题,植物对气候变化的响应反映了植物应对气候变化的生长和生存策略。叶经济性状与植物对资源的获取、利用和储存直接相关,并且受到温度条件和?CO2 浓度的显著影响。该文采用人工环境控制系统封顶式生长室研究广布湿地植物水葱(Scirpus validus)和香蒲(Typha orientalis)的叶经济性状对模拟增温(现行环境温度+2 ℃)和?CO2 浓度倍增(增至?850 μmol·mol-1)的响应。结果表明:(1)增温处理下,水葱净光合速率、氮含量和磷含量显著降低,但其胞间?CO2 浓度和比叶重显著增加;CO2 浓度倍增处理下,水葱胞间?CO2 浓度和净光合速率均显著降低,但比叶重显著增加。(2)增温处理下香蒲的比叶重也显著增加,而氮含量和磷含量显著降低;香蒲的光合参数、氮含量和磷含量在?CO2 浓度倍增处理下均显著降低,而比叶重显著增加。(3)除碳含量外,水葱和香蒲的其他经济性状参数包括净光合速率、气孔导度、蒸腾速率、胞间?CO2 浓度、氮含量、磷含量和比叶重均在响应增温和?CO2 浓度升高过程中均发挥重要作用。总体而言,该研究结果反映了水葱和香蒲在功能性状上对增温和?CO2 浓度升高的响应策略。两种植物的光合能力和养分含量在两种处理下均受到显著的抑制作用,而其抗逆能力升高,表明增温和?CO2浓度升高不利于水葱和香蒲的生长。

submitted time 2022-05-21 Cooperative journals:《广西植物》 Hits213Downloads125 Comment 0

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