从《宣德十年月五星凌犯》看回回历法在明朝的使用

《宣德十年月五星凌犯》是15世纪40年代从中国明朝传入朝鲜李朝的一份重要的天文学文件,详细列出了明宣德十年全年月亮和五大行星之间以及它们对恒星的凌犯现象。经验算,这些结果都是用明初编订的《回回历法》中所给出的算法计算的,目的显然是为中国的凌犯星占服务的,与朱元璋下令翻译回回天文星占著作的初衷一致。新发现的其他史料也表明,明朝政府除了把回回历法用于日月食的预报外,每年还用它计算回回民用历书、天文年历以及月亮和五星的凌犯;而且,对月亮和五星凌犯的计算结果及其星占也确实被朱元璋用于自己的政治活动之中

西方应用人类学百年发展回顾

本文叙述了西方应用人类学的形成时期、发展初期、扩展时期和决策时期4个阶段,回顾了西方应用人类学从19世纪末至今百余年的发展历程。文章认为,西方应用人类学的百年发展,经历了从为殖民统治效力到为民族国家服务的转变,其内容也从较单纯的应用实践,发展到包括基础研究和应用研究在内的综合性研究;我国在人类学学科建设中,应该借鉴西方应用人类学发展的经验教训,开展本土化的应用人类学研究

Decentralized slot synchronization method for Ad Hoc networks

介绍一种用邻居节点的时隙偏差值来计算时隙调整量,从而修正节点的本地参考时隙基准的时隙互同步算法,给出了在信号传播时延情况下时隙偏差的计算方法,证明互同步算法的收敛性,最后给出不同场景下的仿真结果,并对其性能进行分析。该算法由每个节点并行协同计算,实验证明收敛速度快,平均每个节点的计算量小,非常适合于移动自组网的终端终节点运行。A time slot co-synchronization algorithm for modifying the local time slot reference is proposed,the algorithm is using the time slot deviations of neighbor nodes to calculate the slot adjustment.Then a slot deviation computing method under the condition of signal propagation delay is presented and the convergence of this algorithm is proved.Finally,the simulation results of the algorithm for different scenarios are given.Experiments show that this algorithm has fast convergence rate and less computation burden due to the parallel co-computed by each node.Hence,it is very suitable to run on Ad Hoc terminal nodes.国家自然科学基金(61001072);高等学校博士学科点专项科研基金(20100121120020);福建省科技重大专项(2009HZ0003-1);福建省自然科学基金(2010J01347)资助课

Complex ICA based adaptive feedback interference cancelling algorithm for wireless repeaters

为了利用自适应滤波器抵消转发与接收天线间的反馈干扰,根据卷积型混合与独立分量分析ICA解混的原理,将反馈干扰抵消问题纳入了ICA方法的框架中。针对亚高斯复值信号的特点,依据极小化互信息的准则,提出了一种基于复数ICA的自适应算法,简要分析了算法收敛的平衡点并据此给出了新的干扰抵消器的结构。计算机仿真结果表明,相比于lMS算法,所提的算法在反馈信道辨识误差以及输出信号的误差矢量幅度方面有明显的改善。Feedback interference cancelling by using adaptive filters is one of the core technologies of wireless repeaters.The problem was summed up into the framework of ICA in terms of the ICA demixing principle of convolutive mixtures.Aiming at complex signals' subgaussian feature,an adaptive algorithm based on complex ICA was proposed according to minimization of mutual information criterion.The convergence equilibrium point of the proposed algorithm was briefly analyzed and a new structure of interference canceller presented accordingly.Computer simulation demonstrated that the proposed algorithm had obvious performance improvement over conventional LMS in the identification error of feedback path and of the error vector magnitude the output signals'.国家863计划资助项目(2007AA01Z267);福建省重大专项基金资助项目(2009HZ0003-1);福建省教育厅科技项目(JA10251

Fuzzy roughness and rough entropy of covering based generalized rough intuitionistic fuzzy set model

在覆盖粗糙直觉模糊集模型的基础上,将粗糙度和粗糙熵的概念引入到该模型中,研究直觉模糊集的不确定程度,讨论了该度量的相关性质,并通过两个例子证明了直觉模糊集的模糊粗糙度和粗糙熵随着该模型覆盖变细而单调减少。On the basis of the covering rough intuitionistisc fuzzy set model,this paper introduces the notions of roughness and rough entropy,by which the uncertainty measure of intuitionistisc fuzzy set is investigated and their properties are discussed.It is proved that the fuzzy roughness and rough entropy of intuitionistisc fuzzy sets are monotonously decreasing with the subdivision of covering sets by examples.国家自然科学基金资助项目(61379021;11301367;11061004); 福建省自然科学基金资助项目(2013J01029); 闽南师范大学研究生科研立项资助(YJS201409

Modified energy-saving hierarchical data aggregation mechanism for wireless sensor network

考虑WSn中节点的能耗分布情况,提出了一种改进的多级汇聚协议。首先建立分析模型评估了在WSn中采用多级汇聚机制时的能耗情况,证明在SInk附近的汇聚节点的能量增加很快,从而会耗尽能量,缩短整个网络的生存期。然后提出了一个改进的多级汇聚协议,通过改变通过减少离SInk附近的汇聚节点选择概率,可以均衡网络性能。仿真结果证明,该方法可以有效地降低能量,从而延长网络生存期。Considering the distributions of node’s energy consumptions in Wireless Sensor Networks(WSN),a modified hierarchical data aggregation protocol is proposed.Firstly,this paper sets up a simple model to analytically evaluate the energy consumption in WSN by using aggregation mechanism.This paper also shows that energy consumption of an aggregation node increases so rapidly in the neighborhood of the sink node that these nodes will die and shorten the lifetime of the whole network.Secondly,a modified hierarchical data aggregation strategy in order to achieve balanced energy depletion by reduce the cluster head selection probability near the sink is proposed.Simulation results show that,this method can reduce the energy consumption efficiently for sensor networks.So,it can prolong the lifetime of the whole networks.福建省自然科学基金No.A0710021;集美大学优秀青年骨干教师基金资助(No.2008B002)---

Slot synchronization method based on TDMA mobile Adhoc networks

中文摘要: 在 TDMA 体制下的移动网状自组织网络中 ,为了解决网络时隙同步问题 ,提出了一种不依赖 GPS授时的网络时隙互同步算法。各节点通过计算相邻节点的时隙偏差 ,通过加权计算并调整本节点的时隙位置 ,使网内各节点的时隙起始都调整到同一位置上 ,达到时隙的互同步。通过仿真和实验 ,分析并验证了移动自组织网络时隙互同步的收敛性能和抗干扰性能。　　Abstract : In order to resolve the problems of slot synchronization in TDMA mobile ad hoc networks , a method of slot co2synchronization is proposed for mobile ad hoc networks without GPS. The realization of algo2 rithm is presented. Each node measures the off set s of slot starting time with respect to other nodes , calculates the weighted average value and adjust s it s own slot starting time. Finally every node has the same slot starting time and the slot synchronization of ad hoc networks is achieved. Simulation and experiment result s show the convergence and robustness of the proposed algorithm.基金项目:国防技术重点实验室基金(5148303010ZS9318) ;福建省重点科技计划项目(2005H041)资助课

Study on landscape pattern changes in islands under stress of rapid urbanization

以厦门岛为例,通过一般景观格局分析指标和特殊景观格局分析指标,研究城市化进程中海岛生态景观格局的变化以及人工景观对自然景观的胁迫作用。结果显示:从1987年至2004年,人工景观对自然景观的胁迫作用迅速增加;厦门岛建成区占海岛面积的比例迅速增长,而斑块数量明显减少;厦门岛景观多样性迅速下降,同时破碎度指数和优势度迅速提高;受到海岸带开发活动影响,海岛岸线趋向平滑,海岛形状逐步趋向圆形;厦门岛人工景观对自然景观的胁迫程度逐步升高,城市化侵蚀指数也快速提高。Several common and special landscape indices were used to analyze the landscape pattern changes of Xiamen islands and the stress of artificial landscape to the natural landscapes during urbanization process.The results showed that the landscape pattern of Xiamen islands was altered observably and the stress of the artificial landscape to natural landscape were increased rapidly.The ratio of urban land area to the total islands area was increased and the number of the patches was decreased.The landscape diversity was decreased,meanwhile the landscape fragmentation and dominance were increased respectively.Because of the coastal reclamation,the island's coastal line tended to be simple and smooth,and the shape closed to a circle.The stress of the urban land to natural landscapes was aggravated with the urbanization invasion index increase.国家自然科学基金资助项目(40701059);中国科学院知识创新工程重要方向项目(KZCX2-YW-422-1);青年人才领域前沿项目(07l4081d10

Statistical study of trace elemental concentrations in major types oforganisms from typical Chinese coastal waters

研究了微量元素Fe、Mn、Zn、Cu、Sr、Ba在我国典型海域主要生物类别中的概率分布特征,并与常量元素Ca、Mg进行了比较。结果表明,微量元素的概率分布曲线具正偏态性质,概率分布类型大多为对数正态分布或近似对数正态分布,表明对某一特定微量元素,大多数生物体中的含量都比较低,只有个别生物有不成比例的高含量。常量元素Ca与微量元素相似,表现为对数正态分布,而Mg却具正态分布特征。本文给出了我国典型海域生物体中元素含量的总体分布特征。The probability distribution of the trace elements Fe, Mn, Zn, Cu, Sr and Ba in the marine organisms collected from the typical Chinese coastal water swere studied and compared with those of major elements Ca and Mg. All the distributions for the trace elements in macrophytes, benthic molluscs, crustaceans, cephalopods and different tissues in the fish (muscle, liver and bone) were nearly found to show the positive skewness, and a relatively large number of the marine organisms with low concentrations for the element and only a few organisms with disproportionately high concentrations. Their distribution types were generally logarithmic normal distribution or nearly logarithmic normal distribution. Distribution of Ca was similar to the trace elements, while Mg the normal distribution. Average concentrations of the major elements in the organisms were calculated based on their probability distributions.教育部博士学科重点项目(96038412

Performance Analysis Model for IEEE 802.11 Distributed Coordination Function Protocol

提出了一种改进的二维MArkOV链模型用于分析IEEE 802.11 dCf协议.该模型不仅考虑实际应用中饱和业务量和非饱和业务量的情况,而且考虑dCf协议的退避计时器的冻结状态和有限的重传次数.通过对该MArkOV链模型稳定状态的求解并结合M/M/1/k排队模型,导出了dCf系统性能的理论模型.仿真结果表明,该理论模型能够精确地预测广义IEEE 802.11 dCf协议的系统性能.This paper proposes an improved two-dimensional Markov chain model for the performance analysis of the IEEE 802.11 DCF protocol.The model is applicable to both saturated and unsaturated traffic conditions.Moreover,it extends the existing models to take into account previously-ignored MAC layer factors such as backoff freezing and limited times of retry.In addition,by deriving the stationary state of the Markov model and considering an M/M/l/K queuing model,we further derive a theoretical model for evaluating performance of the general IEEE 802.11 DCF protocols.Accuracy of the proposed theoretical model is validated with simulation results.福建省科技重大专项基金(No.2007HZ0003); 福建省自然科学基金(No.2010J01347)资