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991.
改进工作集选择策略的序贯最小优化算法 总被引:3,自引:0,他引:3
针对标准序贯最小优化(sequential minimal optimization, SMO)算法采用可行方向工作集选择策略所带来的缓存命中率低下问题,给出了SMO类型算法每次迭代所带来的目标函数下降量的二阶表达式,并据此提出了一种改进的工作集选择策略.新策略综合考虑算法收敛所需的迭代次数及缓存效率,从总体上减少了核函数计算次数,因此极大提高了训练效率,并且,它在理论上具有严格的收敛保障.实验结果表明,核函数越复杂,样本维度越高,缓存容量相对训练样本的规模越小,改进工作集选择策略的SMO算法相较于标准SMO算法的性能提高就越显著. 相似文献
992.
一种面向多核系统的并行计算任务分配方法 总被引:2,自引:0,他引:2
随着多核处理器的普及,目前的大规模并行处理系统普遍采用多核处理器,这对于资源管理和调度提出了更高的要求.提出了基于共享Cache资源划分的方法,建立了面向多核处理器支持Cache资源分配的进程调度模型,设计并实现了并行任务到多核处理器的映射算法,更好地解决了大规模资源管理系统中面向多核处理器的任务分配问题,降低了使用共享Cache的多个进程运行时的相互干扰,提升了应用程序性能. 相似文献
993.
994.
针对离散时间非线性系统, 提出事件触发传输机制下网络化T-S 模糊控制器设计方法. 在事件发生器中引入前提变量偏差触发条件, 从而取消模糊控制器与被控对象的前提变量之间的同步要求. 通过引入一组基于模糊前提变量特性的松弛等式/不等式, 对于无传输时滞和定常传输时滞两种情况, 分别提出具有较小保守性的控制器/事件发生器联合设计算法. 最后, 通过数值算例表明所提出方法的可行性和有效性.
相似文献995.
Visualizing Waypoints‐Constrained Origin‐Destination Patterns for Massive Transportation Data 下载免费PDF全文
Origin‐destination (OD) pattern is a highly useful means for transportation research since it summarizes urban dynamics and human mobility. However, existing visual analytics are insufficient for certain OD analytical tasks needed in transport research. For example, transport researchers are interested in path‐related movements across congested roads, besides global patterns over the entire domain. Driven by this need, we propose waypoints‐constrained OD visual analytics, a new approach for exploring path‐related OD patterns in an urban transportation network. First, we use hashing‐based query to support interactive filtering of trajectories through user‐specified waypoints. Second, we elaborate a set of design principles and rules, and derive a novel unified visual representation called the waypoints‐constrained OD view by carefully considering the OD flow presentation, the temporal variation, spatial layout and user interaction. Finally, we demonstrate the effectiveness of our interface with two case studies and expert interviews with five transportation experts. 相似文献
996.
Democratizing Journalism – How User‐Generated Content and User Communities Affect Publishers’ Business Models 下载免费PDF全文
Publishers, today, are struggling with their business model: Their efforts to convert traditional content into digital products seem to be insufficient as recipients expect more than simply the mere digitalization of content. Dissatisfied with solely being informed by selected journalists, modern recipients are often interested in acquiring information from various sources, in discussing with others, or even in contributing with their own content. Hence, recipients seem to evolve from being simply readers to contributors themselves. With regard to the established term ‘user‐generated content’, we refer to those co‐creating recipients as users. To underline these assumptions, the present study explores (1) users’ expectations of sources of content and (2) their willingness to provide their own content. Our findings show that both user‐generated content and professional journalists’ content is of value to users. Second, we show that users are mainly driven to contribute by their own expertise, welfare of others, and personal acceptance in the community. With this study, we consider mainly the changed user behaviour in order to derive implications of user involvement for future business models of publishers, in particular on the customer value proposition as well as key resources and key processes. 相似文献
997.
998.
Compact microstrip‐via‐fed wideband circularly polarized antenna with monofilar spiral stub for C‐band applications 下载免费PDF全文
A wideband circularly polarized printed antenna is proposed and fabricated, which employs monofilar spiral stubs and a slit in the asymmetrical ground plane which is fed by an asymmetrical microstrip feedline using a via. The CP operation is realized by embedding an inverted‐L shaped strip and a modified ground plane and can be markedly improved by loading monofilar spiral stubs connected to the asymmetric feedline by means of a via. A parametric study of the key parameters is made and the mechanism for circular polarization is described. After optimization, the impedance bandwidth is approximately 3.6 GHz (4.4‐8 GHz) and the 3 dB axial ratio bandwidth is approximately 3.3 GHz (4.7‐8 GHz), which represent fractional bandwidths of approximately 58.1% and 52%, respectively. Therefore, the proposed antenna is suitable for circular polarization applications in C (4‐8 GHz) band. Compared with other recent works, the simpler structure, wider axial ratio, impedance bandwidths, and more compact size are the key features of the proposed antenna. 相似文献
999.
Hu Changhui Lu Xiaobo Ye Mengjun Zeng Weili Du Yijun 《Multimedia Tools and Applications》2017,76(24):26523-26550
Multimedia Tools and Applications - The extended sparse representation classifier (ESRC) is one of the state-of-the-art solutions for single sample face recognition, but it performs... 相似文献
1000.
Multimedia Tools and Applications - Sparse representation based classification (SRC) and collaborative representation based classification (CRC) are two well-known methods in representation-based... 相似文献