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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
MS Excel内置了系统开发工具VBA可以方便地调用和定制主应用程序对象,用来扩展Microsoft Office应用程序功能。本文利用Excel及其函数和VBA的简单编程功能设计了学员证卡。使学员证卡实现现场采集照片、快速打印系统。 相似文献
992.
993.
电子商务蓬勃发展的大环境下,广告主具有强烈的电商广告投放意愿,显然他们并未达到电商广告的核心业务SEM (搜索引擎营销优化)的专业要求。所以广告主希望借助第三方工具来进行搜索引擎广告投放的一站式服务来满足其业务需求。基于此,本文将提供一整套的竞价词托管式服务的解决方案。以淘宝直通车这一全新的搜索竞价模式作为研究对象,从语义抽取、关键词扩展、竞价词生成、模型化出价、广告效果正向反馈监控模型几方面进行分析和统计,为直通车广告主提供最优投放策略整体解决方案。第一阶段针对商品信息进行数据挖掘,实现关键词推荐引擎。第二阶段实现投放优化模块,实施定价策略,建立的点击量与PPC(“平均点击花费”)模型,实现在预算资金的约束下对不同竞价组合进行ROI(投入产出比)最大化的投资决策。以实际效果改善直通车竞价搜索用户体验。 相似文献
994.
995.
Tungsten oxide (WO3) nanorods array prepared using chemical vapor deposition techniques was studied. The influence of oxygen gas concentration
on the nanoscale tungsten oxide structure was observed; it was responsible for the stoichiometric and morphology variation
from nanoscale particle to nanorods array. Experimental results also indicated that the deposition temperature was highly
related to the morphology; the chemical structure, however, was stable. The evolution of the crystalline structure and surface
morphology was analyzed by scanning electron microscopy, Raman spectra and X-ray diffraction approaches. The stoichiometric
variation was indicated by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. 相似文献
996.
多羟甲基酚多丙烯酸酯的合成及其耐温性能研究 总被引:5,自引:0,他引:5
本文合成了新型耐温活性预聚体多羟甲基酚多丙烯酸酯,并考察了pH值,丙烯酸量,反应时间、反应温度、催化剂用量等因素对反应产率的影响。测试了固化物的TCA和DTA及力学性能,并用红外光谱确认主产物。 相似文献
997.
A novel network model of multiple source fountain coding is developed and a novel class of generic multiple source fountain codes with unequal error protection(UEP)property is proposed.The And–Or tree analysis technique is generalized to analyze the asymptotic performance of the proposed codes and a joint optimization method employing both linear and nonlinear programs is developed to optimize the degree distributions.Furthermore,we propose three basic methods to achieve UEP property and the performance of each method is discussed.We employ these analytical results and optimization method to design and discuss several UEP codes with two and four sources for different application scenarios.Simulation results verify that the proposed codes can be applied to the networks with any number of sources and can provide strong UEP property in various ways based on the proposed three basic methods. 相似文献
998.
This paper proposes a novel relay selection strategy based on the feedback beamforming (BF) information through designed sector sweep (SSW) report frame for millimeter-wave (mmWave) wireless personal networks (WPANs). First, an SSW report frame compatible with IEEE 802.11ad standard is designed. Second, an approach collecting instantaneous channel state information (CSI) overheard during BF is devised. Third, with the aim of minimizing the outage probability and maximizing the overall network throughput capacity, the optimal relay selection issue for non-line-of-sight (NLoS) links is formulated as a bipartite graph, and Kuhn Munkres (KM) algorithm is provided to resolve it. Both theoretical analysis and simulation results show, with CSI considering NLoS conditions and selected relays according to the overall network throughput capacity maximization principle, the improvements achieved over opportunistic relay selection strategy in terms of overall network throughput capacity and outage probability with minimal modifications to IEEE 802.1lad. 相似文献
999.
Gaussian sampling is the major class of algorithms for solving the close vector problem(CVP)of lattices.In this paper we present a novel Gaussian sampling algorithm,which has the same cryptographic applications with original Gaussian sampling algorithms.Our novel Gaussian sampling algorithm has smaller deviations,meaning smaller space sizes of lattice based public-key ciphers.The shape of our novel algorithm is almost repeated implementations of original algorithm,with random repeating times.Major result is that the deviation can be reduced to 0.64~0.75 of that of original Gaussian sampling algorithm without clearly increasing the average time cost. 相似文献
1000.
Boolean functions with high nonlinearity, high resiliency and strict avalanche criterion (SAC) play an important role in the designs of conventional cryptographic systems. In this paper, a method is proposed to construct resilient Boolean functions on n variables (n even) satisfying SAC with nonlinearity 〉 2n-1 -2n/2. A large class of cryptographic Boolean functions that were not known earlier were obtained. 相似文献