基于非度量多维标度的无线传感器网络节点定位算法

把统计学中的多维标度技术应用到无线传感器网络节点定位是一种新的思路.提出了NMDSRSSI(nonmetric multidimensional scaling and received signal strength indication)定位算法,它利用非度量多维标度技术直接根据无线信号强度值来进行节点的定位,省去了以往利用无线信号强度的定位算法中先把强度转换为距离再进行定位所带来的计算误差和计算量.无线信号强度受实际环境影响存在反射、多径传播等问题,理论和实验分析表明算法对此具有较好的适应性.仿真与真实传感器节点的实验结果显示算法取得了较好的定位效果.     

Learnable tabu search guided by estimation of distribution for maximum diversity problems

This paper presents a learnable tabu search (TS) guided by estimation of distribution algorithm (EDA), called LTS-EDA, for maximum diversity problem. The LTS-EDA introduces knowledge model and can extract knowledge during the search process of TS, and thus it adopts dual or cooperative evolution/search structure, consisting of probabilistic model space in clustered EDA and solution space searched by TS. The clustered EDA, as a learnable constructive method, is used to create a new starting solution, and the simple TS, as an improvement method, attempts to improve the solution created by the clustered EDA in the LTS-EDA. A distinguishing feature of the LTS-EDA is the usage of the clustered EDA with effective linkage learning to guide TS. In the clustered EDA, different clusters (models) focus on different substructures, and the combination of information from different clusters (models) effectively combines substructures. The LTS-EDA is tested on 50 large size benchmark problems with the size ranging from 2,000 to 5,000. Simulation results show that the LTS-EDA is better than the advanced algorithms proposed recently.     

An efficient two-staged approach for generating block layouts

Multidimensional scaling (MDS) is a useful mathematical tool that enables the analysis of data in areas where organized concepts and underlying dimensions are not well developed. In this paper, MDS algorithms are used as a dimension reduction tool which arranges facilities in a two-dimensional space while preserving the adjacency relationship between facilities. The output of MDS is a scatter diagram and is in turn used as the input or location references for developing into the final block layout. The bay structures of layout are considered where the given floor space is first partitioned horizontally or vertically into bays, which are subsequently partitioned into the blocks. Rotating the scatter diagram about the origin results in different layouts in the bay structure. A simulated annealing approach is adopted to rotate the scatter diagram so that the total cost of traveling between facilities and shape violation in the final layout is minimized.Scope and purposeThis paper discusses the application of multidimensional scaling (MDS) and simulated annealing (SA) to efficiently design facility layout. MDS is a powerful mathematical tool widely used in psychometry as well as in marketing research. By using MDS to generate a reference scatter diagram, a layout can subsequently be developed. The SA algorithm is then applied to rotate the scatter diagram from MDS so that a layout with the total cost of traveling between facilities being minimized can be obtained.     

Texture mapping using surface flattening via multidimensionalscaling

Presents a novel technique for texture mapping on arbitrary surfaces with minimal distortion by preserving the local and global structure of the texture. The recent introduction of the fast marching method on triangulated surfaces has made it possible to compute a geodesic distance map from a given surface point in O(n lg n) operations, where n is the number of triangles that represent the surface. We use this method to design a surface flattening approach based on multi-dimensional scaling (MDS). MDS is a family of methods that map a set of points into a finite-dimensional flat (Euclidean) domain, where the only data given is the corresponding distance between every pair of points. The MDS mapping yields minimal changes of the distances between the corresponding points. We then solve an "inverse" problem and map a flat texture patch onto a curved surface while preserving the structure of the texture     

Computer simulation of holography for seismic purposes

A method based on the mathematical simulation of holography for getting a special processing of seismic data is discussed. The software system which makes possible the method produces a function that is usable for characterizing the image of the inhomogeneous structure of an underground area or making an ordinary seismic time section corrected according to the seismic velocity, which changes point by point.The method was tried using simulated and measured data and the preliminary experiences seem to indicate that combining software and computer technique with holographic and seismic principles may be successfully used to produce the image of an underground area “explored” by seismic waves or correct the seismic time section belonging to the examined underground part.     

A visual analytics framework for spatio-temporal analysis and modelling

To support analysis and modelling of large amounts of spatio-temporal data having the form of spatially referenced time series (TS) of numeric values, we combine interactive visual techniques with computational methods from machine learning and statistics. Clustering methods and interactive techniques are used to group TS by similarity. Statistical methods for TS modelling are then applied to representative TS derived from the groups of similar TS. The framework includes interactive visual interfaces to a library of modelling methods supporting the selection of a suitable method, adjustment of model parameters, and evaluation of the models obtained. The models can be externally stored, communicated, and used for prediction and in further computational analyses. From the visual analytics perspective, the framework suggests a way to externalize spatio-temporal patterns emerging in the mind of the analyst as a result of interactive visual analysis: the patterns are represented in the form of computer-processable and reusable models. From the statistical analysis perspective, the framework demonstrates how TS analysis and modelling can be supported by interactive visual interfaces, particularly, in a case of numerous TS that are hard to analyse individually. From the application perspective, the framework suggests a way to analyse large numbers of spatial TS with the use of well-established statistical methods for TS analysis.     

Toward a rigorous interpretation of ESML-extended systems modelinglanguage

A graphics-based language known as ESML (extended systems modeling language), which is an extension of the data flow diagram notation for representing control logic in models of real-time systems, is analyzed and summarized to provide a rigorous interpretation of ESML symbols and their combinations. Based on elementary and compact (high-level) Petri nets (PNs), to which a succinct introduction is given, formal foundations for ESML, and in particular for its transformation schema (TS) notation, are proposed. Translation principles as well as examples of usual transformation and flow patterns are presented both in TS and PN notation. The resulting PN models are rigorous and accurate models of the dynamics of real-time systems with signals, prompts, and data flows of various kinds. Due to their formally defined token game they can be executed and used to study indeterminism and concurrency of events     

一种抗DPA攻击的双轨信号平行布线方法

双轨预充电逻辑是一种有效的差分功耗分析(DPA)攻击防护技术,其需要解决的关键问题在于必须保证互补的双轨信号线具有对称的电容负载.本文提出了一种双轨信号布线方法,能够基于商用的布局布线EDA工具实现双轨信号的平行布线,从而实现电容负载对称的目的.本方法首先利用EDA工具在奇数个布线轨道中对单轨网表进行布线,然后将信号线...     

基于MFC开发的振动信号监测与分析软件

利用微震测量技术、数据采集技术与信号处理技术可以建立一套监测各种振动信号的系统,广泛应用于各种振动事件的监测与报警。该文介绍了该系统的软件的设计思路与实现的效果。采用VC++,基于MFC类库开发了一套振动信号监测与分析软件,实现数据实时采集、信号分析处理、振动事件判别报警、数据存储回放等功能。     

地震灾害潜在损失评价模型分析与研究——以唐山地震为例

地震灾害潜在损失评价模型的研究是综合应用遥感和地理信息系统技术,估算潜在地震灾区可能的最大损失量,以及潜在震区直接和间接的最大经济损失,为震区灾后的重建提供辅助决策支持信息。     

Fuzzy multidimensional scaling

Multidimensional scaling (MDS) is a data analysis technique for representing measurements of (dis)similarity among pairs of objects as distances between points in a low-dimensional space. MDS methods differ mainly according to the distance model used to scale the proximities. The most usual model is the Euclidean one, although a spherical model is often preferred to represent correlation measurements. These two distance models are extended to the case where dissimilarities are expressed as intervals or fuzzy numbers. Each object is then no longer represented by a point but by a crisp or a fuzzy region in the chosen space. To determine these regions, two algorithms are proposed and illustrated using typical data sets. Experiments demonstrate the ability of the methods to represent both the structure and the vagueness of dissimilarity measurements.     

基于重叠变换的地震数据压缩去噪

近来有研究表明重叠正交变换(LOT)对压缩地震信号非常有效。与LOT相比,多分辨重叠双正交变换(HLBT)对信号频谱的非均匀划分,可以更加有效地将能量集中在有限的变换域子带(TransformBins)上。论文利用HLBT,针对地震数据中信号和噪声的特点,融合信号去噪和数据压缩,实现地震信号的高保真压缩。试验结果表明,对于高倍率的压缩,其效果要优于目前的小波压缩算法。     

基于WWW检索EDA资源信息的方法与技术

EDA（电子设计自动化）技术是当今电子技术发展的前沿之一,它将电子系统软件设计与硬件设计融为一体,为电子产品开发,电子系统设计,电子系统工程提供了全新的手段,阐述了在WWW上如何利用搜索引擎技术及工具进行EDA资源的搜集,整理工作,介绍了方法与技术可有效地提高EDA教学水平,具有很强的实践性。     

周期信号加时窗后的频谱分析与仿真研究

研究工作中用EDA工具对周期性信号作频谱分析问题时,由此得到的频谱分析与周期性信号频谱的理论分析存在着一定的偏差.理论的信号幅度谱具有谐波性,是离散的谱线,而仿真环境下的谱线在频率点有畸变.通过信号谱分析的理论,结合EDA仿真工具分析的特点,将两种频谱分析的偏差来源归结于周期信号的时域加窗效应.分析r频谱产生偏差的原因,并对理论分析谱和仿真分析谱的特点给予归纳.最后的仿真分析也证实了给出的分析结果.     

Exploring,confirming, and randomization tests

In the context of randomization tests, this paper discusses the roles of exploratory data analysis (EDA) and confirmatory data analysis (CDA) in geoscience research. It shows: (1) how the classical methods of statistical inference can be used in EDA with nonrandom samples of data, and (2) how much of the knowledge in the geosciences is derived from EDA. The paper gives a FORTRAN IV computer program, CLASSTEST, that performs a randomization test for a multivariate analysis of variance (MANOVA) design. CLASSTEST will be useful in goescience research apart from its use in illustrating EDA and CDA.     

基于盲源分离的ICA去噪技术在裂缝预测中的应用

地震记录中不可避免地包含随机干扰信号,直接利用原始的地震资料开展裂缝发育带预测,对裂缝预测中采用的边缘检测算法影响很大,降低了预测结果的准确性。因此,有必要对地震资料进行去除噪声的处理,提高原始地震资料的品质。本文基于盲源分离的独立分量分析方法(Independent component analysis,ICA)去噪技术,将地震资料分解为不同级次的背景与储层目标反射响应,实现有效信号与随机噪声的区分,去噪效果优于常规去噪算法的效果,保证了去噪后有效信息基本不受损失,处理后地震资料横向波形特征的稳定性得到了较好改善。实际工区应用效果表明,利用去噪处理后的地震资料开展边缘检测裂缝预测,裂缝发育区分布规律与区域断裂发育特征具有较好的一致性,且与钻井揭示的裂缝发育特征吻合性较好,从而提高了火成岩裂缝发育区预测的可靠性。     

Segmentation of a seismic section using image processing and artificial intelligence techniques

Methods for segmenting stacked seismic data into zones of common signal character based on texture analysis are described. Their performance is demonstrated on a line of seismic data from the Gulf of Mexico that had been manually segmented. Two segmentation methods are described. The first is a template matching scheme that matches previously selected data templates with a block of pixels. The second uses statistics determined by examining the run-length of seismic reflection events. The run-length method is extended, through a decision process called the RESOLVER, to incorporate heuristic rules to influence the segmentation. A comparison is made between the automatic segmentations of the section and a manual interpretation.     

提高光栅数字地震检波器精度的方法研究

在地震勘探系统中,随着数据记录系统动态范围的突破,地震检波器的动态范围已不能满足系统的要求,提高检波器的精度和动态范围变成地震勘探技术研究的关键.光栅数字地震检波器的研制成功,提高了检波器的精度和动态范围.通过对光栅传感器机理的深入分析,采用5细分专用芯片为核心的细分电路,成功实现了光栅脉冲信号的20倍细分技术.在采用100线计量光栅的情况下,使检波器分辨率达到0.000 5 mm,动态范围达到75dB.并采用PIC单片机系统完成了振动信号的再现.该方法将有助于光栅数字地震检波器的性能完善,为实现高精度地震勘探技术奠定基础.     

Are use case and class diagrams complementary in requirements analysis? An experimental study on use case and class diagrams in UML

Despite the status of united modeling language (UML) as the de facto standard for object oriented modeling, it has received controversial reviews. The most controversial diagram in UML is the use case diagram. Some practitioners claim that use case diagrams are not valuable in requirements analysis and some have even argued that use case diagrams should not be part of UML. This research examined the values of use case diagram in interpreting requirements when use case diagrams are used in conjunction with class diagrams. In other words, the study investigated the possible synergetic values and relationships between the use case and class diagrams in the context of requirements analysis. This study used theories from cognitive psychology as its theoretical and conceptual foundation. The data collection utilized the verbal protocol technique in which subjects were asked to think aloud as they interpreted the use case and class diagrams. The results show that the use case diagrams were more completely interpreted than the class diagrams. The presence or absence of one diagram when interpreting another diagram had no effect on the outcome of the interpretation. From the results, we argue that the use case diagrams and class diagrams depict different aspects of the problem domain, they have very little overlap in the information captured, and both are necessary in requirements analysis.     

Zero-order TS fuzzy model to predict hydro turbine speed in closed loop operation

This paper addresses the development of new hydro plant model using a zero-order Takagi–Sugeno (TS) fuzzy approach. The control signal and turbine speed are identified as input–output variable of the plant. The said model is determined with two fuzzy sets using data generated from widely accepted second-order H-infinity and Padé transfer function (TF) plant model operating in closed loop through digital PID control.The parameters in fuzzy inference system are adaptively tuned using gradient-descent optimization technique. The performance of identified zero-order TS fuzzy model is demonstrated accurately and thus suitable for turbine speed dynamics study.