Results 11 to 20 of about 164,546 (209)

基于长期保存标准的保存成本模型比较与分析 [PDF]

open access: yes, 2016
引入 OAIS 参考模型、ISO 16363 可信赖仓储认证标准、DCC 生命周期模型,比较分析长期保存主要 成本模型覆盖上述标准所包含活动的范围程度,并结合成本模型的自身特征,说明呈现该覆盖程度的原因。分 析表明: 成本模型与 3 个长期保存标准有较好的兼容性,长期保存成本模型研究与实践已有较大发展,然而这 些模型还不具备很好的实用性,在很多方面还有待完善和改进。
吴振新, 陈瑶
core   +1 more source

基于知识晶炼理论的产品设计过程决策服务建模 [PDF]

open access: yes, 2019
[目的/意义]旨在服务于产品设计过程中的问题解决方案决策,同时满足知识检索和重用的需求,保障产品的可持续发展。 [方法/过程]基于知识晶炼双循环模型,发现现有 IBIS 模型及其改进模型均存在问题。因此,用知识晶炼双循环模型将研讨对话模型和产品设计过程连接,构建支持产品双循环模型的 IBIS 表示。传统的研讨对话模型在模糊综合决策判断时使用了取大取小算子,由于这种算子会导致某些有用元素无效的情况,因而将取大取小算 子替换为 Einstain 算子。[结果/结论] Einstain ...
吴晓凤, 高峰
core   +1 more source

国外数字资源长期保存成熟度模型及其分析与评价 [PDF]

open access: yes, 2017
[目的/意义]介绍能力成熟度模型原理,研究和分析成熟度模型在长期保存中的应用,为国内长期 保存系统的建设和发展提供参考。[方法/过程]通过对成熟度模型的概念、原理和应用介绍,详细介绍长期保 存领域具有代表性的 3 个能力成熟度模型,从适用性、可行性和可持续性的角度分析模型的优劣势。[结果/结 论]通过对比分析给出相关模型的评述以及对成熟度模型的实践思考,总结当前数字资源长期保存成熟度模型 的发展现状及趋势,提出构建符合我国长期保存发展需求的成熟度模型的必要性和重要意义。
吴振新, 孙超
core  

Comparison of fertilizer-effect models on winter wheat response to nitrogen and phosphorus fertilizers in saline soils in the Yellow River Delta [PDF]

open access: yes, 2017
通过大田试验, 研究了黄河三角洲盐碱土地区冬小麦合适的肥料效应模型。在冬小麦生长季设置4种不同的氮磷肥用量, 根据“3414”试验设计8 种不同的肥效试验处理, 以探讨线性加平台、一元二次、平方根和二元二次4 种不同模型的拟合效果。结果显示, 4 种肥料效应模型的拟合结果经检验都达到极显著水平 (P<0.01)。在一元肥料效应模型中, 氮磷一元二次模型拟合效果最好, 最高收益分别为7 448.3 元·hm-2 和7 357.7 元·hm-2 ...
付希强   +8 more
core   +1 more source

Urbanization and Seasonality Increase Introduced Plant Consumption by the World's Southernmost Parrot 城市化与季节性增加了全球最南端鹦鹉对引入植物的取食

open access: yesIntegrative Conservation, EarlyView.
Urbanization may alter bird foraging. Austral Parakeets (Enicognathus ferrugineus) in Patagonia rely on introduced plants in urban areas, especially in winter, despite preferring natives in the wild. This seasonal reliance on introduced species highlights urbanization trade‐offs and underscores the need to manage green areas with native plants to ...
Rocío Bahía   +2 more
wiley   +1 more source

Sun Bear Ecology and Conservation: Multiscale Habitat Associations in Southeast Asia 马来熊的生态与保护:东南亚地区的多尺度生境关联研究

open access: yesIntegrative Conservation, EarlyView.
We collated detections of the sun bear from new and previously published camera trap studies across its range. We then analysed these detections at two different spatial scales to assess the habitat associations and diel activity of this species. We found that the sun bear is tolerant to moderate habitat disturbances. ABSTRACT Degraded tropical forests,
Alexander Hendry   +5 more
wiley   +1 more source

Are Galliformes of the High Himalayas Well Protected? Identifying Conservation Priority Areas Using an Assemblage‐Level Approach 高喜马拉雅地区的鸡形目鸟类是否得到了有效保护?利用群落水平方法确定优先保护区域

open access: yesIntegrative Conservation, EarlyView.
This study investigates distribution patterns of Galliforms in the Indian Himalayas, focusing on factors influencing their occurrence, regions of high diversity and endemism, and their overlap with protected areas. Our study highlights the need for assemblage‐level conservation strategies in high Himalaya which primarily relies on snow leopard‐focused ...
Manvi Sharma   +5 more
wiley   +1 more source

同步协作信息检索模型及其机制研究 [PDF]

open access: yes, 2009
通过分析当前用户协作信息检索的相关理论和系统实践,总结其中存在的一些问题,确定用户同步协作检索中要解决的三个关键问题:检索任务的分配、群组查询历史的重用和协作感知,提出一个用户同步协作信息检索模型 ...
刘兰, 徐树维, 齐惠颖
core  

Impacts of Human Development on Wildlife Use of Corridors in Botswana 人类开发对博茨瓦纳野生动物廊道利用的影响

open access: yesIntegrative Conservation, EarlyView.
This study examined the effect of landscape‐scale human impact on wildlife in Botswana. We examined how species use wildlife corridors in two different human‐dominated landscapes. We identified differences in temporal overlap between wildlife and humans across both landscapes, which is fundamental to consider in both current and future conservation ...
Tempe S. F. Adams   +3 more
wiley   +1 more source

The Application of VaR Method Based on the MS-GARCH Model in Securities Asset Management Market [PDF]

open access: yes, 2016
近几年来,我国券商资产管理业务取得了突飞猛进的发展,然而相应的风险管理学术研究较少。为了研究券商资管市场的风险管理VaR方法,本文选取股票型券商理财指数作为数据处理对象,假定模型的扰动项分别服从正态分布、t分布、广义误差分布、偏t分布、偏广义误差分布,采用单一状态GARCH族模型(GARCH模型、EGARCH模型、GJR-GARCH模型、APARCH模型)对数据进行建模。之后,文章在GARCH模型中引入马尔可夫状态转换过程,构建MS-GARCH模型 ...
何浩
core  

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