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51.
52.
优选状态数的MCMC算法在风电功率序列生成中的应用 总被引:1,自引:0,他引:1
传统马尔科夫链蒙特卡洛(MCMC)法的状态数选择常依赖于人工经验,应用于风电功率序列建模时难以较好地同时模拟原始风电功率序列的概率分布特性和自相关特性。针对该问题,提出一种优选状态数的MCMC(OSN-MC)算法。首先给出MCMC方法状态数的选取范围,其次在该范围内以生成序列与原始序列的自相关函数的误差平方和最小为原则确定优选状态数,然后利用各状态对应功率范围内的累积分布函数抽样生成随机风电功率,提高优选状态数下生成风电功率序列对于原始序列分布特性的模拟精度。应用OSN-MC法和MCMC法对中国、美国和欧洲的12个风电场生成风电功率序列,并与原始实测序列进行特性比较,结果表明:OSN-MC法生成的风电功率序列对原始序列的分布特性和自相关特性的模拟效果均优于MCMC法所生成的风电功率序列。 相似文献
53.
针对无线传感器网络网关通信方式单一、灵活性差的问题,设计并实现了一种自适应WSN监控系统网关,网关能够根据工作环境选择以太网、WiFi、GPRS通信方式中的一种来转发无线传感器网络的数据;基于STM32F107微处理器完成了网关的硬件开发和软件设计,实现了数据汇集、通信方式的选择、远程通信等功能;基于VC++完成了监控中心软件的开发,实现了数据接收、图形化显示、存储、查询等功能;搭建校园温湿度监控系统对网关性能进行测试,测试结果表明,该网关有扩展灵活、可靠性高、使用方便等特点。 相似文献
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Mao-Yuan Pai Hui-Chuan Chu Su-Chen Wang Yuh-Min Chen 《Expert systems with applications》2013,40(6):1993-2006
Since eWOM provides a rich source of objective information about products or services, it has become one of the major ways in which consumers collect information about items they are interested in buying. However, the problem of eWOM overload makes it difficult to effectively collect this information, and may have adverse effects on their actual purchase behavior. eWOM content is characterized by unstructured text formats, oversimplified expressions, and newly coined phrases (textspeak), and these all contribute to the challenges that arise when analyzing eWOM. This study thus proposes an eWOM analysis method for analyzing eWOM, which may lead to a more effective method for analyzing eWOM content, extracting both positive and negative appraisals, and help consumers in their decision making. At the same time, the method proposed in this study can also be utilized as a tool to assist companies in better understanding product or service appraisals, thus translating these opinions into business intelligence and as the basis for product/service improvements. 相似文献
56.
Abstract Recently, Gao and Tu presented an efficient algorithm for robust low bit‐rate video transmission by using a partial backward decodable bit stream (PBDBS) approach. In this paper, we first present a multiple‐PBDBS (MPBDBS) approach to improve on the previous PBDBS approach. Next a mathematical theory is provided to minimize the error propagation length in each group of blocks (GOB). Further, a novel MPBDBS‐based algorithm is presented for robust video transmission. Experimental results demonstrate that our proposed MPBDBS‐based algorithm has better image quality when compared to the previous PBDBS‐based algorithm, but has some bit‐rate and execution‐time degradation. In our experiments, both single and two‐bit error models are investigated. 相似文献
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Ashish Nadar Atindra Mohan Banerjee M.R. Pai R.V. Pai Sher Singh Meena R. Tewari A.K. Tripathi 《International Journal of Hydrogen Energy》2018,43(1):37-52
Supported iron oxides have been established as an important class of catalyst for high temperature sulfuric acid decomposition. With an objective to elucidate the role of support in modifying the overall catalytic properties of dispersed iron oxide catalysts, a series of supported iron oxide based catalysts, Fe2O3 (15 wt%)/MO2 (M = Zr, Ce, Ti and Si), synthesized by adsorption-equilibrium method, is investigated for sulfuric acid decomposition reaction. The structure of dispersed iron oxide phases largely depended on the nature of the support oxide as revealed by the XRD and Mössbauer studies. α-Fe2O3 is found to be present as a major phase on ZrO2 and CeO2 support while ε-Fe2O3 was the major phase on silica supported iron oxide. On the other hand, presence of mixed oxide Fe2TiO5 was revealed over TiO2 support. Strong dispersed metal oxide-support interactions inhibited the total reduction of the dispersed phase on SiO2 and TiO2 as compared to complete reduction of dispersed iron oxide on CeO2 and ZrO2 supports during temperature programmed reduction upto 1000 °C. The order of catalytic activity at a temperature of ~750 °C is observed as Fe2O3/SiO2 > Fe2TiO5/TiO2 > Fe2O3/ZrO2 > Fe2O3/CeO2, while at higher temperatures of ~900 °C the SO2 yield is found to be comparable for all catalysts. A relationship between the rate of sulfate decomposition and catalytic activity is established through detailed TG-DTA investigations of sulfated catalyst and support. Considerable influence of the support oxide on the composition, structure, redox properties, morphology and catalytic activities of the active iron oxide dispersed phase has been observed. Thus, the support oxides operate as a critical component in the complex supported metal oxide catalysts and these findings might influence the design and development of future high temperature sulfuric acid decomposition catalysts. 相似文献
59.
Pei-Yan Pai 《Expert systems with applications》2012,39(1):154-161
In this paper, a nucleus and cytoplast contour detector (NCC detector) is presented to automatically detect the cytoplast and nucleus contours of a cell in a cervical smear image. The NCC detector uses the adaptable threshold decision (ATD) method to separate the cell from the cervical smear image, and then uses the maximal gray-level-gradient-difference (MGLGD) method, proposed in this paper, to extract the nucleus from the cell. The experimental results show that the NCC detector is superior to two existing methods, the gradient vector flow-active contour model (GVF-ACM) and the edge enhancement nucleus and cytoplast contour (ENNCC) detector, in segmenting the cytoplast and nucleus of a cell. 相似文献
60.
Yan-Hom Li Ching-Yao Chen Shih-Tsung Sheu Jay-Min Pai 《Microfluidics and nanofluidics》2012,13(4):579-588
The dynamics of microchains containing superparamagnetic particles in an oscillating field are studied experimentally. The chains are first formed by a static directional field, and then manipulated by an additional dynamical perpendicular field. The present methodology represents a simple reversible chaining process, whose particles can be re-dispersed after removal of the field. The motion of superparamagnetic chains is dominated by magnetic torque and induced hydrodynamic drag. The effects of key parameters, such as field strengths and the lengths of particle chains, are thoroughly analyzed. Distinct behaviors, from rigid body oscillations and bending distortions to rupture failures, are observed by increasing the amplitudes of oscillating fields or chains’ lengths. Because of lower induced drag, a shorter chain follows the field trajectory closely and oscillates more synchronically with the external field. On the other hand, the influences of field strengths are not consistent. Even the overall oscillating phase trajectory in a stronger external field deviates less significantly from the corresponding field trajectory, a stronger dynamical component of the external field results in larger phase angle lags at certain points. The experimental results confirm the criterion of ruptures can be effectively determined by the value of (N*Mn 1/2), where Mn is the Mason number defined as the ratio of induced drag to dipolar attraction, and N represents the number of particles contained in a chain. 相似文献