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21.
针对人类用自然语言与机器交互所面临的巨大鸿沟,提出了一种基于类自然语言的语义对象行为语言。SOBL是一种宣称式的陈述语言,用于开发数据库驱动的应用,支持复杂的用户交互,主要由一个Semantic Objects^TM的对象关系开发框架所支持。该语言扩展结构化自然语言,携带语义信息,能够面向非程序员使用,降低了软件的开发难度。最后通过一个具体的实例验证了该语言的有效性。  相似文献   
22.
With the advancement of MEMS technologies, sensor networks have opened up broad application prospects. An important issue in wireless sensor networks is object detection and tracking, which typically involves two basic components, collaborative data processing and object location reporting. The former aims to have sensors collaborating in determining a concise digest of object location information, while the latter aims to transport a concise digest to sink in a timely manner. This issue has been intensively studied in individual objects, such as intruders. However, the characteristic of continuous objects has posed new challenges to this issue. Continuous objects can diffuse, increase in size, or split into multiple continuous objects, such as a noxious gas. In this paper, a scalable, topology-control-based approach for continuous object detection and tracking is proposed. Extensive simulations are conducted, which show a significant improvement over existing solutions.  相似文献   
23.
现在很多部门都需要通过规则处理海量情报数据,规则的数量一旦达到海量级规模,对规则的处理技术的要求将会变得越来越高,海量规则的优化将是一个十分重要的问题.文中展示了一种海量规则的优化方法.若两个规则网最后的计算结果是一样的,则可以认为这两个规则网是等价的.基于该等价规则模块的变换可以将代价小的规则模块替换掉代价大的规则模块,从而以后可以选择一种代价最小的规则模块.本文提出规则网模块等价替换的5种优化方法,并对其做了相应的证明.通过优化,可以使得海量规则网处于计算代价尽量最小状态,以此减少处理机的计算工作量.分析表明,通过等价规则替换,可以大大提高规则处理效率.  相似文献   
24.
A handwritten Chinese character recognition method based on primitive and compound fuzzy features using the SEART neural network model is proposed. The primitive features are extracted in local and global view. Since handwritten Chinese characters vary a great deal, the fuzzy concept is used to extract the compound features in structural view. We combine the two categories of features and use a fast classifier, called the Supervised Extended ART (SEART) neural network model, to recognize handwritten Chinese characters. The SEART classifier has excellent performance, is fast, and has good generalization and exception handling abilities in complex problems. Using the fuzzy set theory in feature extraction and the neural network model as a classifier is helpful for reducing distortions, noise and variations. In spite of the poor thinning, a 90.24% recognition rate on average for the 605 test character categories was obtained. The database used is CCL/HCCR3 (provided by CCL, ITRI, Taiwan). The experiment not only confirms the feasibility of the proposed system, but also suggests that applying the fuzzy set theory and neural networks to recognition of handwritten Chinese characters is an efficient and promising approach.  相似文献   
25.
In this work, we have demonstrated that amorphous ZnO nanobranches (a-ZnO NBs) could spontaneously react from the crystalline ZnO NWs (c-ZnO NWs) at specific humid environment. The spontaneous reaction mechanism and result can be analyzed by humidity controlling and optical microscope (OM)/scanning electron microscope (SEM)/Kelvin probe force microscopy (KPFM)/transmission electron microscopy (TEM) system. We can make the c-ZnO NWs spontaneous reaction happen at different humid environments and suppress the a-ZnO NBs spontaneous reaction by oxygen/hydrogen plasma surface passivation. The hydrogen plasma surface treatment also can improve the UV sensing sensitivity more than twofold. This work provides the mechanism and methods of the a-ZnO NBs spontaneous growth and offers the passivation treatment for strengthening and enhancing ZnO-based nanodevice application in humid environment and UV light detection, respectively.  相似文献   
26.
The effect of non-uniform temperature on the sorption-enhanced steam methane reforming (SE-SMR) in a tubular fixed-bed reactor with a constant wall temperature of 600 °C is investigated numerically by an experimentally verified unsteady two-dimensional model. The reactor uses Ni/Al2O3 as the reforming catalyst and CaO as the sorbent. The reaction of SMR is enhanced by removing the CO2 through the reaction of CaO + CO2 → CaCO3 based on the Le Chatelier's principle. A non-uniform temperature distribution instead of a uniform temperature in the reactor appears due to the rapid endothermic reaction of SMR followed by an exothermic reaction of CO2 sorption. For a small weight hourly space velocity (WHSV) of 0.67 h?1 before the CO2 breakthrough, both a low and a high temperature regions exist simultaneously in the catalyst/sorbent bed, and their sizes are enlarged and the temperature distribution is more non-uniform for a larger tube diameter (D). Both the CH4 conversion and the H2 molar fraction are slightly increased with the increase of D. Based on the parameters adopted in this work, the CH4 conversion, the H2 and CO molar fractions at D = 60 mm are 84.6%, 94.4%, and 0.63%, respectively. After CO2 breakthrough, the reaction of SMR dominates, and the reactor performance is remarkably reduced due to low reactor temperature.For a higher value of WHSV (4.03 h?1) before CO2 breakthrough, both the reaction times for SMR and CO2 sorption become much shorter. The size of low temperature region becomes larger, and the high temperature region inside the catalyst/sorbent bed doesn't exist for D ≥ 30 mm. The maximum temperature difference inside the catalyst/sorbent bed is greater than 67 °C. Both the CH4 conversion and H2 molar fraction are slightly decreased with the increase of D. However, this phenomenon is qualitatively opposite to that for small WHSV of 0.67 h?1. The CH4 conversion and H2 molar fraction at D = 60 mm are 52.6% and 78.7%, respectively, which are much lower than those for WHSV = 0.67 h?1.  相似文献   
27.
This study investigates the influence of blood vessels on temperature distribution during high-intensity focused ultrasound (HIFU) ablation of liver tumors. A three-dimensional acoustics-thermal-fluid coupling model is simulated to compute the temperature field in the hepatic cancerous region. The model is based on the linear Westervelt and bioheat equations as well as the non-linear Navier–Stokes equations for the liver parenchyma and blood vessels. The effect of acoustic streaming is also taken into account in the present HIFU simulation study. We found from this three-dimensional coupling study that in large blood vessel both the convective cooling and acoustic streaming can significantly change the temperature field and thermal lesion near blood vessels.  相似文献   
28.
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   
29.
The aim of this study was to analyse the composition of okra (Abelmoschus esculentus L.) extract and investigate the effect of A. esculentus L. polysaccharides (AE-PS) on the maturation and function of dendritic cells (DCs) derived from rat bone marrow hematopoietic cells (BMHCs) in vitro. BMHC-derived immature DCs (BMHC-imDCs) were extracted from rats and treated with AE-PS. The hydrolysed okra extract contained 0.6% β-1, 3-d-glucan. AE-PS induced the presence of polymorphic nuclei and elongated protrusion in the BHMC-imDCs, indicating DC activation. Treatment with100 μg/mL of AE-PS increased the MHC class II and CD80/86 expression levels by 41% and 42%, respectively. Treated cells had reduced endocytosis activity. The secretion of IL-12 and IFN-γ increased significantly by 120% and 75%, respectively, when treated with 100 μg/mL of AE-PS. Moreover, IL-10 production was reduced by 66%. In conclusion, AE-PS exhibits stimulatory effects on rat dendritic cells and promotes the secretion of TH1 cytokines.  相似文献   
30.
A sputtering technique was adopted to synthesize Sn-Cu thin film electrodes. Island Sn particles were obtained on the copper foil. Cu6Sn5 was spontaneously generated at the interface between Sn and Cu foil. To further improve the cycling stability, Cu source was introduced to increase the formation of Cu6Sn5 and to serve as a buffer during cycling. Moreover, the phase and elemental ratio of Sn and Cu varied in the synthesized electrode by alternately adjusting sputtering time for Sn and Cu. The cell synthesized by sputtering Sn for 5 min and Cu for 9 s alternately exhibited the best cycling stability. The 1st charge capacity of cell was 635 mA hg−1, and the 1st efficiency was even higher than 97%. The capacity remained higher than 500 mA hg−1 after 15 cycles. The phase transformation of cell was investigated through voltage profile, CV curve and in situ XRD analysis. The in situ XRD analysis confirmed that Cu6Sn5 could react with lithium directly without the presence of Li2CuSn during cycling. The reaction mechanism of Cu6Sn5 with lithium during cycling was demonstrated to be an alloying process, and the structure of Cu6Sn5 was thus a low-temperature monoclinic phase.  相似文献   
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