排序方式: 共有93条查询结果,搜索用时 312 毫秒
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大规模MIMO系统时分双工模式中分配的物理时隙长度是固定的,不能根据不同时长的信道相干时间灵活地调整长度,二者长度的不匹配导致部分时频资源的浪费,因此系统的总体容量不能达到最优。针对此问题本文提出一种用户分层变长时隙分配方法,即根据不同终端的移动性对终端进行分层,并为不同层中的移动终端灵活地分配不同时长的物理时隙,使物理时隙长度与移动终端所对应信道的相干时长相匹配,从而减少时频资源的浪费,提高了资源利用率。同时,避免了低速移动终端过频繁的信道估计,降低了信道训练序列开销,使系统的总体数据容量得到很大的提升。实验仿真结果验证了本文所提方法的有效性。 相似文献
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张锡成 《兵团教育学院学报》2001,11(1):1-2
初步查明果子沟有野生药用植物 189种 ,隶属于 5 4科 16 0属。资源储量不足 ,名贵中药材面临灭绝的危险 ,亟应加强对野生药用植物资源的保护 相似文献
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薛洁 《兵团教育学院学报》2001,11(3):17-18
钟敬文阐明了民族的整体文化与民俗文化的关系,确定了民俗文化在整体文化中的重要地位。他指出文化认同是实施西部大开发战略的首要前提。钟敬文的文化观对保护和利用新疆民族文化资源,推动新疆经济文化建设具有指导意义。 相似文献
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针对标准LDPC码译码中洪水消息传递机制的不足,提出以串行机制进行消息传递,按照变量节点的顺序进行消息处理和传递,对每个变量节点同时接收校验消息和发送变量消息。该方法使更新的消息能够很快进入当前迭代计算,改善了LDPC迭代译码的收敛性能。通过对几种常用译码算法的仿真比较,验证了在复杂度不增加的情况下,该方法性能优于其它几种最大后验概率准则的译码方法,且算法收敛快,是一种能较好兼顾性能与实现复杂度的译码方法。 相似文献
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吴景贵 《中国人民武装警察部队学院学报》2011,(9):87-89
原生文献是一所学校成立以来,在教学、科研及各项管理工作中产生的特色文献资源。以武警学院为例,从原生文献的基本概念入手,对原生文献资源建设的意义以及如何进行原生文献资源建设等方面进行了一些探讨。 相似文献
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本文以石河子大学理学院新审批土地资源管理专业为例,根据土地科学的学科性质和土地管理实际工作对人才规格的需求,结合兵团实际,主要从人才培养目标定位、课程体系构建,师资队伍培养、实践教学体系及实践教学平台搭建等四个方面对该专业人才培养方案与体系进行了初步的探索与实践。 相似文献
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William Hutchins Seitz 《Defence and Peace Economics》2013,24(4):425-441
Using an event study approach to analyze stock market data from the United States, I investigate how regulations on conflict minerals sourced in the Democratic Republic of the Congo were perceived by investors. I find that for a subset of mining companies, stock returns were abnormally high when regulations in the US became more likely. I also find that returns were higher for communications equipment manufacturing companies when strong regulations in the DRC were announced. I argue that these responses were due to the competitive environments faced by each of these company types. These findings relate to debates surrounding the effects of the conflict mineral regulations. While some critics argue that reporting requirements were tantamount to a ban on minerals from the DRC, I find that stock returns for a subset of companies were sensitive to legislation in the DRC after legislation became law in the US, suggesting that market participants did not expect a complete trade ban on regulated mining and trading activities. 相似文献
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Kelemework Tafere Reda 《African Security Review》2013,22(3):270-278
Based on a literature review, this article examines the dynamics in pastoral systems, natural resource conservation and conflict in the drylands of East Africa. It argues that, in the context of East Africa, pastoralism and biodiversity conservation in general are distinct forms of land use that are complementary rather than competitive. The present state of natural resource degradation in the drylands is explained in terms of factors related to ecological and demographic pressures, land use conflicts and inefficient land administration policies. When the customary pastoral institutions of land administration and resource management are threatened, the problem of degradation is further exacerbated and violent conflicts occur among multiple resource users, including pastoralists, farmers and the state. The article recommends the revitalisation, empowerment and recognition of pastoral institutions in a way that ensures effective synergy between the formal and customary structures of resource governance. 相似文献
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Testing provides essential information for managing infectious disease outbreaks, such as the COVID-19 pandemic. When testing resources are scarce, an important managerial decision is who to test. This decision is compounded by the fact that potential testing subjects are heterogeneous in multiple dimensions that are important to consider, including their likelihood of being disease-positive, and how much potential harm would be averted through testing and the subsequent interventions. To increase testing coverage, pooled testing can be utilized, but this comes at a cost of increased false-negatives when the test is imperfect. Then, the decision problem is to partition the heterogeneous testing population into three mutually exclusive sets: those to be individually tested, those to be pool tested, and those not to be tested. Additionally, the subjects to be pool tested must be further partitioned into testing pools, potentially containing different numbers of subjects. The objectives include the minimization of harm (through detection and mitigation) or maximization of testing coverage. We develop data-driven optimization models and algorithms to design pooled testing strategies, and show, via a COVID-19 contact tracing case study, that the proposed testing strategies can substantially outperform the current practice used for COVID-19 contact tracing (individually testing those contacts with symptoms). Our results demonstrate the substantial benefits of optimizing the testing design, while considering the multiple dimensions of population heterogeneity and the limited testing capacity. 相似文献