Using sign algebra for qualitative spatial reasoning about the configuration of mechanisms

This paper presents a novel approach to qualitative spatial reasoning about the spatial configuration of mechanisms that could be applied in the earlier phases of mechanism design. The basic idea in this approach is to predict all possible spatial configurations of a mechanism using sign algebra. This paper addresses spatial configuration problems of direction, position, and orientation of mechanisms. Spatial configuration matrices are introduced to describe and manipulate the spatial information of primitive mechanisms. Using these matrices, the overall spatial configurations of a complicated mechanism are constructed and then they are expressed by spatial configuration state matrices. These matrices are composed based on sign algebra and used to reason about all possible spatial solutions of a mechanism. The qualitative spatial reasoning proposed in this paper could provide useful prior information on the spatial configuration of mechanisms earlier in the conceptual design of mechanisms. The proposed approach is illustrated with a design example.     

安全空间数据库动态审计策略的研究与应用

提出了一种基于安全空间数据库管理系统的动态审计策略模型。该模型不仅能够充分表达基于时间和空间的审计策略,还可以根据约束机制对系统用户行为进行实时监控。通过引入复合属性表达式,表达细粒度的审计策略。最后在自主开发的安全空间数据库管理系统Sec_Vista中,内嵌了审计规则触发模块、约束规则触发模块和日志触发模块,实现了本审计策略。     

Learning control in spatial coordinates for the path-following of autonomous vehicles

We prove the existence of a P-type (proportional-type) space-learning control, which, on the basis of a kinematic third order nonlinear model of an autonomous nonholonomic vehicle and by a proper choice of the proportional control gain, guarantees asymptotic tracking of planar curves whose uncertain curvature is L$L$-periodic in the curvilinear abscissa. The behavior of a human driver, who repetitively learns the correct action from the past experience in the space, is mathematically reproduced. A stability analysis is presented while simulation results demonstrate the effectiveness of the presented approach.     

Modeling interregional commodity flows with incorporating network autocorrelation in spatial interaction models: An application of the US interstate commodity flows

Spatial interaction models are frequently used to predict and explain interregional commodity flows. Studies suggest that the effects of spatial structure significantly influence spatial interaction models, often resulting in model misspecification. Competing destinations and intervening opportunities have been used to mitigate this issue. Some recent studies also show that the effects of spatial structure can be successfully modeled by incorporating network autocorrelation among flow data. The purpose of this paper is to investigate the existence of network autocorrelation among commodity origin–destination flow data and its effect on model estimation in spatial interaction models. This approach is demonstrated using commodity origin–destination flow data for 111 regions of the United States from the 2002 Commodity Flow Survey. The results empirically show how network autocorrelation affects modeling interregional flows and can be successfully captured in spatial autoregressive model specifications.     

The development and application of CAD/CAM workstations in the GDR

For accomplishing low-attended manufacture, step by step, it is necessary that information handling in technological production planning, management and shop control processes is organized economically. This is especially true with respect to computer-aided product development and production planning, faster order throughput, control of production equipment and delivery of information needed for high equipment utilization with a simultaneous increase in the volume of data processed automatically. These complex requirements call for a new type of approach in information handling technology (CAD/CAM) and corresponding layouts of workstations for the designer and manufacturing engineer. Such CAD/CAM facilities should be user-friendly so that they can be adapted to the user's need and not vice versa.     

A system for the capture and synthesis of insect motion

We present an integrated system that enables the capture and synthesis of 3D motions of small scale dynamic creatures, typically insects and arachnids, in order to drive computer generated models. The system consists of a number of stages, initially, the acquisition of a multi-view calibration scene and synchronised video footage of a subject performing some action is carried out. A user guided labelling process, that can be semi-automated using tracking techniques and a 3D point generating algorithm, then enables a full metric calibration and captures the motions of specific points on the subject. The 3D motions extracted, which often come from a limited number of frames of the original footage, are then extended to generate potentially infinitely long, characteristic motion sequences for multiple similar subjects. Finally a novel path following algorithm is used to find optimal path along with coherent motion for synthetic subjects.     

空间信息技术在物联网中的作用与应用研究

物联网技术的发展需要空间信息理论与技术的支撑,而空间信息技术也必将在物联网的时代背景与机遇下推广其应用。文中分别介绍了空间信息技术与物联网的产生及其应用,在此基础之上总结归纳了空间信息技术在物联网中的作用,同时探讨了空间信息技术在物联网中的应用。     

On the Dengfeng–Chuntian similarity measure and its application to pattern recognition

Recently Dengfeng and Chuntian defined the first operational definition of a similarity measure for intuitionistic fuzzy sets and showed how it may be used in pattern recognition problems. Unfortunately the Dengfeng and Chuntian operator may give counter-intuitive results. We show how a simple modification of the Dengfeng–Chuntian operator may correct this problem. We illustrate the application of the modified similarity measure on a simple pattern recognition problem.     

关于AUTO CAD在图形图像教学领域的多元结合应用

AUTO CAD是一款交互式计算机辅助设计以及绘图的软件,在传统的教学中很多学生都认为这款软件的学习十分困难,所以很难提起学习兴趣,还有一些学生学习了后面的知识就会忘记前面的知识,这就使得教学质量与效率很难提升。为此,教师应积极主动探索有效的教学方式,激发学生的ATUO CAD软件的学习兴趣,提升教学和学习的质量。本文就探讨ATUO CAD在图形图像教学领域的多元结合应用。     

Optimizing the spatial pattern of networks for monitoring radioactive releases

This study presents a method to optimize the sampling design of environmental monitoring networks in a multi-objective setting. We optimize the permanent network of radiation monitoring stations in the Netherlands and parts of Germany as an example. The optimization method proposed combines minimization of prediction error under routine conditions with maximizing calamity detection capability in emergency cases. To calculate calamity detection capability, an atmospheric dispersion model was used to simulate potentially harmful radioactive releases. For each candidate monitoring network, we determined if the releases were detected within one, two and three hours. Four types of accidents were simulated: small and large nuclear power plant accidents, deliberate radioactive releases using explosive devices, and accidents involving the transport of radioactive materials. Spatial simulated annealing (SSA) was used to search for the optimal monitoring design. SSA was implemented by iteratively moving stations around and accepting all designs that improved a weighted sum of average spatial prediction error and calamity detection capability. Designs that worsened the multi-objective criterion were accepted with a certain probability, which decreased to zero as iterations proceeded. Results were promising and the method should prove useful for assessing the efficacy of environmental monitoring networks designed to monitor both routine and emergency conditions in other applications as well.     

Reducing the spatial distance between printed and online information sources by means of mobile technology enhances learning: Using 2D barcodes

Online information sources, such as pictures and animations on web pages are frequently used for complementing printed course material in educational contexts. The concurrent use of online and printed information sources by students, however, requires going back and forth between physically separated course material, such as a course book and a computer screen, thus leading to suboptimal learning outcomes. Compatible with the principles identified by the recent theoretical frameworks for multimedia learning, mobile technology provides learners with the opportunity to bring online and printed course material close together. Mobile phones make online information available within a small desktop space, in close proximity to printed course material. The challenges that are relevant to text input methods can be overcome by the 2D barcode technology. This study investigates the use of camera-equipped mobile phone and 2D barcode technology as an alternative to the use of computer screen for complementing printed course material. The results of the experimental investigation suggest that, by facilitating the access to online information sources by 2D barcode tags on course books, mobile phones have the potential to enhance learning.     

Exploration of architectural spaces by blind people using auditory virtual reality for the construction of spatial knowledge

Navigation within a closed environment requires analysis of a variety of acoustic cues, a task that is well developed in many visually impaired individuals, and for which sighted individuals rely almost entirely on visual information. For blind people, the act of creating cognitive maps for spaces, such as home or office buildings, can be a long process, for which the individual may repeat various paths numerous times. While this action is typically performed by the individual on-site, it is of some interest to investigate at which point this task can be performed off-site, at the individual's discretion. In short, is it possible for an individual to learn an architectural environment without being physically present? If so, such a system could prove beneficial for navigation preparation in new and unknown environments. The main goal of the present research can therefore be summarized as investigating the possibilities of assisting blind individuals in learning a spatial environment configuration through the listening of audio events and their interactions with these events within a virtual reality experience. A comparison of two types of learning through auditory exploration has been performed: in situ real displacement and active navigation in a virtual architecture. The virtual navigation rendered only acoustic information. Results for two groups of five participants showed that interactive exploration of virtual acoustic room simulations can provide sufficient information for the construction of coherent spatial mental maps, although some variations were found between the two environments tested in the experiments. Furthermore, the mental representation of the virtually navigated environments preserved topological and metric properties, as was found through actual navigation.     

试析信息技术在学校档案管理中的应用

研究信息技术在学校档案管理中的应用具有极大的现实意义.传统学校档案管理方式存在诸多不足,主要表现在工作效率低、保密性差、档案检索和维护难度较大等方面.现代化学校档案管理系统既有数据处理速度快、容量大、检索方便等优点,也具有相关法律不健全、档案易改等不足.实现学校档案管理工作的信息化要作到：提高档案管理的标准化水平,做好学校档案数据库的建设工作,加强办公自动化建设,学校档案管理工作人员要具备优良的素质.     

On the choice of spatial and categorical scale in remote sensing land cover classification

Our interest in this paper is on the choice of spatial and categorical scale, and their interaction, in creating classifications of land cover from remotely sensed measurements. We note that in discussing categorical scale, the concept of spatial scale naturally arises, and in discussing spatial scale, the issue of aggregation of measurements must be considered. Therefore, and working towards an ultimate goal of producing multiscale, multigranular characterizations of land cover, we address here successively and in a cumulative fashion the topics of (1) aggregation of measurements across multiple scales, (2) adaptive choice of spatial scale, and (3) adaptive choice of categorical scale jointly with spatial scale. We show that the use of statistical finite mixture models with groups of original pixel-scale measurements, at successive spatial scales, offers improved pixel-wise classification accuracy as compared to the commonly used technique of label aggregation. We then show how a statistical model selection strategy may be used with the finite mixture models to provide a data-adaptive choice of spatial scale, varying by location (i.e., multiscale), from which classifications at least as accurate as those of any single spatial scale may be achieved. Finally, we extend this paradigm to allow for jointly adaptive selection of spatial and categorical scale. Our emphasis throughout is on the empirical quantification of the role of the various elements above, and a comparison of their performance with standard methods, using various artificial landscapes. The methods proposed in this paper should be useful for a variety of scale-related land cover classification tasks.     

On a computationally simple form of the generalized Campbell–Baker–Hausdorff–Dynkin formula

In this paper a computationally simple form of the generalized Campbell–Baker–Hausdorff–Dynkin formula (GCBHD) is given. Simplifications arise from both combinatorial (explicit) as well as algorithmic (implicit) arguments. On generating the Ph. Hall basis in a special form, and introducing a specific structure representation of the vector field, vector fields appearing in GCBHD are automatically transformed into the reduced Ph. Hall basis. The formula can be exploited in nonholonomic motion planning what is illustrated with examples.     

Information visualization; assisting low spatial individuals with information access tasks through the use of visual mediators

This study investigated the use of visual mediators to facilitate information access by low spatial individuals. Based on theories of adaptive learning and field-dependence, two human-computer interfaces were developed which were intended to compensate for the inability of low spatial individuals to readily construct visual mental models of a menu system's structure. The two compensatory interfaces included: a 2D visual hierarchy and a linear structure. The information search performance of high and low spatial individuals was compared on the two compensatory interfaces and a third challenge match interface, which challenged individuals to construct a mental model of a hierarchical menu system in order to perform efficiently. The visual mediators were successful in accommodating low spatial individuals, as indicated by the lack of any significant performance differences being detected between the high and low spatial groups on the two compensatory interfaces. High spatial individuals outperformed low spatial individuals only when information search tasks required the use of spatial ability in mentally constructing a model of the organization and structure of embedded task information. The key factor in the accommodation process was the elimination of the need to mentally visualize the structure of embedded task information. These results indicate that visualization techniques can be successfully used to enhance the information search performance of low spatial individuals.     

A novel full‐wave CAD for the design of tapered leaky‐wave antennas in hybrid waveguide printed‐circuit technology

This work presents a novel computer‐aided design (CAD) tool for the design of tapered leaky‐wave antennas (LWAs) in hybrid waveguide printed‐circuit technology. The software package is composed of several tools, which are connected together to provide a semi‐automated step‐by‐step design procedure. The design procedure is presented and the different tools are described, together with the involved theory, leading to the design of tapered LWAs. A practical taper design is performed, and comparisons with simulations using commercial software (HFSS) are presented for validation purposes. Due to the full‐wave nature of the technique used in the analysis engine, excellent agreement is shown between the proposed 2D‐based approach, and 3D HFSS results. Also, the analysis procedure is fast, thus leading to semi‐automated designs that are not affordable with common 3D optimization techniques. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

On the computation of the Ratliff–Rush closure

Let R be a Cohen–Macaulay local ring with maximal ideal m. In this paper we present a procedure for computing the Ratliff–Rush closure of an m-primary ideal IR.     

Verification of the analysis method for extracting the spatial continuity of the vegetation distribution on a regional scale

Vegetation plays a key role in not only improving urban environments, but also conserving ecosystems. The spatial continuity of vegetation distributions can be expected to make green corridors for landscape management, wind paths against heat island phenomena. In this paper, we develop a spatial analysis method of vegetation distributions using remotely sensed data on a regional scale. The method consists of a spatial autocorrelation analysis, an overlay analysis, and a hydrological analysis with the Normalized Difference Vegetation Index (NDVI) adopted as the proxy of vegetation abundance. Application of the method leads to the extraction of the lines between the core areas and sparse areas of vegetation. The purpose of this study is to verify our method through applying a vegetation map digitized from aerial photographs. The map contained three vegetation types of land cover: grasslands, agricultural fields, and tree-covered areas. We use remotely sensed data collected at four different time periods at the regional scale, along with information on the seasonal fluctuations of the vegetation. As a result, the exclusion of seasonal land-cover changes, as in the reaping of agricultural fields, in the process of applying the proposed method produces an effect. The analysis reveals steady areas unaffected by the seasonal fluctuation of vegetation along the lines extracted by applying the proposed method.