主题图相关问题探讨

如SGML/XML描述数据结构一样,主题图(Topic Map)描述了语义链接网络结构。运用SGML／XML置标对原始数据进行加工创建信息,运用主题图对信息集合进行加工创建知识结构。本文对主题图基本内容、主题图模板与主题图的自动生成做了简要的介绍。     

网络处理器的程序设计方法

在网络节点处理串行数据流时，通常将数据流处理功能构造为单向或双向的内部高速输入输出系统，分析其特征可知：它们的数据包处理流程和程序设计方法基本相同，但网络处理器的速度和带宽不相同。本文以IPv6典型的数据包处理流程为例，重点探讨IXP2XXX网络处理器的数据结构和操作过程、微引擎缟程模型和程序设计方法。     

Correspondence of document file structures to discipline structures

Online data bases might be more valuable to users if their structures more closely matched those of the disciplines represented by the data bases. To explore this concept, a structure for the field of tropical medicine was derived from the interrelationships of signs and symptoms of 37 tropical diseases. A similar structure was derived for the interrelationships of sign and symptom index terms applied to articles on these topical diseases in the MEDLINE data base. The poor correlation of the two structures led to the suggestion that rigorous indexing of articles with sign and symptom index terms or check tags would enhance the usefulness of the data base. Similar studies could be envisioned for other disciplines and data bases.     

A novel technique for optimal placement of piezoelectric actuators on smart structures

The problem of positioning of actuators and sensors on smart materials has been a point of interest in recent years. This is due to the fact that in many practical applications there are limitations in space, weight, etc. of the smart structures, which make the problem of positioning more complex. In addition, it is required that the actuators/sensors have the best possible performance. The development of smart structures technology in recent years has provided numerous opportunities for vibration control applications. The use of piezoelectric ceramics or polymers has shown great promise in the development of this technology. The employment of piezoelectric material as actuators in vibration control is beneficial because these actuators only excite the elastic modes of the structures without exciting the rigid-body modes. This is important since very often only elastic motions of the structures are needed to be controlled. The purpose of this paper is to introduce a novel approach developed for optimizing the location of piezoelectric actuators for vibration suppression of flexible structures. A flexible fin with bonded piezoelectric actuators is considered in this study. The frequency response function (FRF) of the system is then recorded and maximization of the FRF peaks is considered as the objective function of the optimization algorithm to find the optimal placement of the piezoelectric actuators on the smart fin. Three multi-layer perceptron neural networks are employed to perform surface fitting to the discrete data generated by the finite element method (FEM). Invasive weed optimization (IWO), a novel numerical stochastic optimization algorithm, is then employed to maximize the weighted summation of FRF peaks. Results indicate an accurate surface fitting for the FRF peak data and an optimal placement of the piezoelectric actuators for vibration suppression is achieved.     

福清市土地开发与管理决策支持系统设计及应用

以福清市土地开发与管理决策支持系统为例,提出了基于数据分析和功能分解的综合应用“3S”空间信息技术的土地管理决策信息系统设计范式和途径。建立了系统的实体－关系的数据分析模型和相应的数据流和数据库逻辑和物理结构,并利用设计的系统实现了福清市上迳乡土地变化动态J土地开发管理;地理信息系统;决策支     

基于时间序列Sentinel-1A数据的玉米种植面积监测研究

玉米作为中国三大作物之一,监测其种植面积对及时了解其种植时空分布、保障粮食安全具有重要作用。本文以河北省涿州市为研究区,利用2016年多时相Sentine-1A SAR （Synthetic Aperture Radar, 合成孔径雷达）影像,对玉米种植区域进行提取。在对研究区地物散射特性分析的基础上,分析了微波后向散射特性随不同生育期玉米植株结构发育的变化情况,选择合适时相和极化组合的后向散射系数,运用支持向量机（Support Vector Machine,SVM）算法提取了玉米种植范围和面积信息,并对不同后向散射系数（标准后向散射系数（Sigma-naught,σ₀）和归一化后向散射系数（Gamma-naught,γ₀））用于研究区作物种植区提取的结果进行了比较。结果表明,采用时间序列（4月19日,5月30日,6月11日,7月17日）雷达图像得到的监督分类结果具有较高的分类精度和kappa系数,总体精度达92.96％,Kappa系数为0.91。因此,采用4—7月（春玉米播种至吐丝时期、夏玉米播种至拔节时期）的时间序列SAR数据能有效获取不同种植模式下的玉米信息,而增加8、9月的数据对玉米识别精度的影响不大。总体来说,采用多时相双极化的σ₀数据与相同时相组合的γ₀数据对玉米种植范围提取基本相同,但使用γ₀数据的林地识别精度比σ₀数据提高了3％。研究结果可为多极化SAR数据的玉米识别和面积监测提供参考案例。     

Microstructured multi-well plate for three-dimensional packed cell seeding and hepatocyte cell culture

In this article, we present a microstructured multi-well plate for enabling three-dimensional (3D) high density seeding and culture of cells through the use of a standard laboratory centrifuge to promote and maintain 3D tissue-like cellular morphology and cell-specific functionality in vitro without the addition of animal derived or synthetic matrices or coagulants. Each well has microfeatures on the bottom that are comprised of a series of ditches/open microchannels. The dimensions of the microchannels promote and maintain 3D tissue-like cellular morphology and cell-specific functionality in vitro. After cell seeding with a standard pipette, the microstructured multi-well plates were centrifuged to tightly pack cells inside the ditches in order to enhance cell-cell interactions and induce formation of 3D cellular structures during cell culture. Cell-cell interactions were optimized based on cell packing by considering dimensions of the ditches/open microchannels, orientation of the microstructured multi-well plate during centrifugation, cell seeding density, and the centrifugal force and time. With the optimized cell packing conditions, we demonstrated that after 7 days of cell culture, primary human hepatocytes adhered tightly together to form cord-like structures that resembled 3D tissue-like cellular architecture. Importantly, cell membrane polarity was restored without the addition of animal derived or synthetic matrices or coagulants.     

产业领域专利合作状态与演化分析——以人工智能领域为例

【Purpose/significance】From the perspective of patent cooperation status and evolution, this paper reveals the re⁃ lationship structures and changes between the main body of technology in the industry and the country or region to which it belongs.【Method/process】The research framework is constructed with social network analysis. This paper takes the field of artificial intelligence industry as an example, using the Derwent patent database as the data source to extract data infor⁃ mation about patentees from the obtained patent data. Combined with the technology life cycle in the field of artificial intel⁃ ligence, this paper finally analyzes the stage evolution characteristics of the overall structure and node characteristics of the patent cooperation network at the institutional and national levels from two dimensions of time and space.【Result/conclu⁃ sion】It is found that the scale of the artificial intelligence patent cooperation network has shown explosive growth, the net⁃ work has evolved in a more connected direction. The patent cooperation network between countries has a small-world ef⁃ fect, the cooperation and exchanges in the industry are more frequent, and the cooperation relationship is getting closer; the United States is in a leading position in the cooperation network of the artificial intelligence, China and Japan are playing important roles.     

TaxoFolk: a hybrid taxonomy–folksonomy classification for enhanced knowledge navigation

Taxonomy is widely used in many of the website and directory navigation schemes for content/knowledge retrieval. However, information or content navigation support through taxonomy is often constrained due to its inability to take into account the full nomenclature and cultural nuances of knowledge seekers. The emergence and increasing adoption of collaborative tagging (social bookmarking) tools have provided lightweight and informal conceptual structures called folksonomies for knowledge retrieval. As for folksonomies, they reflect the vocabulary of the users. Hence, integrating folksonomies into a taxonomy combines the best of the two schemes as the resultant structure enhances taxonomy navigation with personsalisation for knowledge search and retrieval. This paper presents TaxoFolk, an algorithm for deriving hybrid taxonomy-folksonomy classification for enhanced knowledge navigation. The algorithm integrates folksonomy with a taxonomy through several unsupervised data mining techniques with augmented heuristics.     

Near-duplicate video detection featuring coupled temporal and perceptual visual structures and logical inference based matching

We propose in this paper an architecture for near-duplicate video detection based on: (i) index and query signature based structures integrating temporal and perceptual visual features and (ii) a matching framework computing the logical inference between index and query documents. As far as indexing is concerned, instead of concatenating low-level visual features in high-dimensional spaces which results in curse of dimensionality and redundancy issues, we adopt a perceptual symbolic representation based on color and texture concepts. For matching, we propose to instantiate a retrieval model based on logical inference through the coupling of an N-gram sliding window process and theoretically-sound lattice-based structures. The techniques we cover are robust and insensitive to general video editing and/or degradation, making it ideal for re-broadcasted video search. Experiments are carried out on large quantities of video data collected from the TRECVID 02, 03 and 04 collections and real-world video broadcasts recorded from two German TV stations. An empirical comparison over two state-of-the-art dynamic programming techniques is encouraging and demonstrates the advantage and feasibility of our method.     

Browsing mixed structured and unstructured data

Both structured and unstructured data, as well as structured data representing several different types of tuples, may be integrated into a single list for browsing or retrieval. Data may be arranged in the Gray code order of the features and metadata, producing optimal ordering for browsing. We provide several metrics for evaluating the performance of systems supporting browsing, given some constraints. Metadata and indexing terms are used for sorting keys and attributes for structured data, as well as for semi-structured or unstructured documents, images, media, etc. Economic and information theoretic models are suggested that enable the ordering to adapt to user preferences. Different relational structures and unstructured data may be integrated into a single, optimal ordering for browsing or for displaying tables in digital libraries, database management systems, or information retrieval systems. Adaptive displays of data are discussed.     

基于专利数据挖掘的情报分析研究——以能源桩领域为例

作为一种新型的建筑桩基和地源热泵的结合形式,建筑能源桩在可再生能源利用中日益受到重视.本文基于专利数据挖掘,从申请趋势、申请人国别、申请类别、审查结论、重要申请人等方面分析了建筑能源桩结构相关的专利申请,指出了相关技术由早期的桩基结构和材料、换热管的连接和排布、桩和管的连接逐渐向结构多样化、工艺精细化、桩管集成化发展,...     

快速独立分量变换与去噪初探

独立分量分析 (ICA)通过对非高斯分布数据进行有效表示 ,获得在统计学上独立的各个分量。这种表示可以获取数据的基本结构 ,包括特征提取和信号分离。简述ICA基本理论和快速算法 ,对照主分量分析 (PCA)的Karhunen Loeve(K L)变换 ,提出独立分量变换 (ICT)概念。在分析地震信号特点的基础上 ,对模拟和实际含噪地震道进行独立分量变换、信噪分离和去噪处理初步探索 ,重建获得令人满意的去噪结果。研究表明 ,ICA在勘探地震信号处理中具有应用前景     

突发事件演化的耗散结构判断模型研究

运用熵和耗散结构对突发事件演化进行分析,明确突发事件演化过程符合耗散结构非线性及动态变化的特性,据此对经典布鲁塞尔器(Brusselator)模型进行转义处理,建立突发事件演化的耗散结构判断模型。依据模型构建正负熵指标体系,判断事件演化的受控性是否满足耗散结构的有序平衡状态。最后依据事故资料,对2013年某输油管道泄漏事故进行分析,分析结果与实际事故的发展过程具有良好的吻合性,可为突发事件的应急决策提供有益的借鉴。     

Design and implementation of a rectangular frequency invariant beamformer with a full azimuth angle coverage

A novel design of the frequency invariant beamformer based on a rectangular array is proposed with two unique features: there are no taped delay-lines (TDLs) or any other temporal processing involved and the resultant beamformer has a full 360° azimuth angle coverage. This leads to a wideband beamformer with complex-valued coefficients and its implementation is not as straightforward as the traditional ones. Depending on whether the input signal is complex-valued or real-valued, special arrangements and structures are required for its effective implementation. Several design examples are provided with a satisfactory frequency invariant property. Two sets of implementation results are given based on both simulations and data collected by a planar microphone array system.     

Learning a subspace for clustering via pattern shrinking

Clustering is a basic technique in information processing. Traditional clustering methods, however, are not suitable for high dimensional data. Thus, learning a subspace for clustering has emerged as an important research direction. Nevertheless, the meaningful data are often lying on a low dimensional manifold while existing subspace learning approaches cannot fully capture the nonlinear structures of hidden manifold. In this paper, we propose a novel subspace learning method that not only characterizes the linear and nonlinear structures of data, but also reflects the requirements of following clustering. Compared with other related approaches, the proposed method can derive a subspace that is more suitable for high dimensional data clustering. Promising experimental results on different kinds of data sets demonstrate the effectiveness of the proposed approach.     

复杂晶体的化学键和非线性光学效应

系统地提出了复杂晶体化学键的介电理论方法 ,计算了一些非线性晶体的二阶极化系数dij.计算结果和实验值符合很好 ,同时表明这种方法不仅可应用于复杂晶体 ,还提供了材料设计的某些依据 .     

三维裂隙网络渗流路径识别算法及其优化

裂隙化岩体广泛存在于地表浅层,为主要的地下水渗透介质之一,而裂隙网络构成地下水及溶质在裂隙化岩体中运移的主要甚至唯一导水通道.根据图论知识将裂隙网络概化为非连通图,采用图这种数据结构表示三维裂隙网络数据.编写了计算机程序识别裂隙化岩体中沿水力梯度方向的渗流路径,剔除对渗流无贡献的裂隙,可明显缩短裂隙网络地下水渗流与溶质运移数值模拟计算时间,使大尺度裂隙网络渗流与溶质运移模拟研究与工程应用的可行性显著提高.     

High-performance microfluidic rectifier based on sudden expansion channel with embedded block structure

A high-performance microfluidic rectifier incorporating a microchannel and a sudden expansion channel is proposed. In the proposed device, a block structure embedded within the expansion channel is used to induce two vortex structures at the end of the microchannel under reverse flow conditions. The vortices reduce the hydraulic diameter of the microchannel and, therefore, increase the flow resistance. The rectification performance of the proposed device is evaluated by both experimentally and numerically. The experimental and numerical values of the rectification performance index (i.e., the diodicity, Di) are found to be 1.54 and 1.76, respectively. Significantly, flow rectification is achieved without the need for moving parts. Thus, the proposed device is ideally suited to the high pressure environment characteristic of most micro-electro-mechanical-systems (MEMS)-based devices. Moreover, the rectification performance of the proposed device is superior to that of existing valveless rectifiers based on Tesla valves, simple nozzle/diffuser structures, or cascaded nozzle/diffuser structures.     

Necessary and Sufficient Conditions for Cerenkov Radiation

It is shown that in the case of charged beams of finite dimensions and/or finite electromagnetic wave-guiding structures, the condition v&c/n is a necessary but not a sufficient condition for generation of Cerenkov radiation. Depending upon the modulation, size and geometry of the beams, and dimensions of the wave-guiding structures, selected lines can be eliminated from the radiation spectrum. Since the lines in the spectrum are size and geometry dependent it is suggested that the analysis of the Cerenkov radiation spectrum may be utilized in the determination of sizes and shapes of charged particles.