基于GIS三维地形的数字高程模型建模实例

简述了数字高程模型的概念,包括数字高程模型的三维地形表面建模原理、方法及技术,并给出使用VC++生成和读取DEM数据的实例。     

基于数字地面模型的公路实时三维动画

研究了一种用数字地面模型和公路设计数据实现实时三维动画的方法。首先利用Delauany三角化方法构造数字地面模型，然后将公路设计数据与数字地面模型进行叠加。为解决叠加过程中的相容性问题，提出了先将地界约束边界线插入Delauany三角形网格，然后重新三角化的方法。为加快渲染速度，提出了多分辨率显示和网格数据结构相结合的加速措施。文中的方法在实践中得到了验证。     

一种基于四叉树结构的动态多分辨率地形模型

结合油田可视化项目,文章根据三维地形可视化中利用四叉树存储DEM数据的方法,提出了一种与视点相关的动态多分辨率地理模型的构造算法,主要讨论了该模型的多分辨率地形表示机制以及动态地形简化方法和评价函数等问题,试验结果表明,文中的算法达到了预期目的,能应用于地形场景的三维可视化和漫游。     

Parallel Processing for Terrain Analysis in GIS: Visibility as a Case Study

The application of parallel processing to computationally intensive GIS problems has been advocated and illustrated by many researchers over the last twenty years. Despite this, GIS users have been slow to capitalize on the potential which the technology offers. Whilst todays processors are adequate for the majority of GIS uses, some applications are too processor-intensive to be deemed viable for serial machines. This is particularly true of many digital terrain modelling applications, which has been the primary focus of parallel processing in GIS to date.This paper considers the problem of parallelizing line-of-sight (LOS) calculations in determining the visibility indices of entities such as elevation vertices in a digital terrain model (DTM). This is a requirement of site selection for a particular development, especially if visibility, or more specifically, visual intrusion is likely to be a key factor in gaining planning approval. To demonstrate the simplicity and applicability of parallelizing such GIS problems, this paper presents some parallel approaches in an efficient data organization, framework using a Transputer network. Speed-up performance can be increased by a factor of twelve using a simple network of twenty Transputers. As vast quantities of spatial data become available, particularly DTMs at larger scales and denser resolution, the demands for parallel processing will inevitably increase. It is hoped that the continued experiences of todays researchers at applying parallel processing to well-defined problems will benefit the GIS users of tomorrow.     

夷平面数字地形模型的生成、显示与分析初探——以美武高原为例

以甘南美武高原太子山地区典型夷平面为例,利用遥感与计算机技术,对夷平面三维数字地形模型的生成、显示与定量分析方法进行了探索,为夷平面显示的直观性、准确性和定量化研究提供一种新的途径。并利用这一方法,对美武高原典型残余夷平面的分级、坡度、坡度变化率、相对高差等反映地貌形态的数量特征进行了计算、统计与分析,第一次提出了该地区残余夷平面的准确数值特征,为进一步深入研究打下了坚实的基础。     

夷平面数字地形模型的生成、显示与分析初探-以美武高原为例

以甘南美武高原太子山地区典型夷平面为例，利用遥感与计算机技术，对夷平面三维数字地形模型的生成、显示与定量分析方法进行了探索，为夷平面显示的直观性、准确性和定量化研究提供一种新的途径。并利用这一方法，对美武高原典型残余夷平面的分级、坡度、坡度变化率、相对高差等反映地貌形态的数量特征进行了计算、统计与分析，第一次提出了该地区残余夷平面的准确数值特征，为进一步深入研究打下了坚实的基础。     

我国主要牧区雪灾遥感监测与评价系统中的数字地形分析及其信息传输

介绍了我国主要收区雪灾遥感监浏中的数字地形信息的计算、存储、格式转换和传输技术。数字地形信息在整个雪灾遥感监浏评价系统中是一种较重要的地理信么，它主要用来对空间信息进行定位控制，并为空间分析操作和应用模型分析提供能反映地理分布特征的信息。对数字地形信息的计算模型、特点及存贮结构进行了较为详细的介绍。数字地形信息是一种栅格数据，而作为雪灾遥感监测评价来统的PC ARC/lNFO空间操作是一种比较完备的地理信息来统，在数据格式上有其自己的特点，数字地形信息只有经过一定的格式转换和数据传输，才能在PC ARC/INFO中进行各类空间操作，达到整个来统设计的目的。如何将数字地形信息转换成PC ARC/INFO能接收的栅格数据结构文件是整个雪灾遥感监浏评价来统中的一个重要外部数据格式转换接口，对该部分内容也进行了详细的介绍。     

设计特征模型到分析特征模型的自动转换方法

针对有限元分析建模的需求,提出一种将工程零件的设计特征模型自动转换为相应的分析特征模型的方法.首先将设计特征模型分解为所有正特征剩余体的集合,然后从各正特征剩余体中分解出一组扫成体和非扫成体,再采用基于二维轮廓的方法从各扫成体中确定出候选分析特征区域,最后通过合成候选分析特征区域得到真正的分析特征区域,并在此基础上生成分析特征和分析特征模型.实验结果表明该方法是有效的.     

高职院校组织管理模式影响数字校园建设策略分析

本文在比较分析不同时期我国高职院校组织管理模式的基础上,结合智慧校园、云计算平台等校园信息化建设的理论,深入分析了其对高职院校数字校园建设的影响,提出我国未来高职院校数字校园建设的策略是：依托统一的云平台,结合院校的管理现状,建设行政管理、学术管理、后勤管理三大业务系统平台。     

Six Ways from Sunday: Approaches to Indexing Digital Text Images

In 1994, the Andrew W. Mellon Foundation funded a joint project undertaken by the Center for Research Libraries (CRL) and the Latin American Microfilm Project (LAMP) to scan and index over three-hundred thousand pages of microfilmed Brazilian Government Documents for the Internet. Due to the collection size, format, language and poor physical condition of the text, entering this overwhelmingly textual collection as full-text was prohibitively expensive. Instead the documents were scanned as images, thereby maintaining the intellectual content of the collection, but losing the dynamic searching capabilities inherent in full-text databases. A combination of indexing approaches was used to provide access to these documents. Indexing (table-of-contents, pagination and subject indexes) found in the documents were recreated to give users access to the documents. A controlled vocabulary was established to index a portion of the database. The factors of costs, user feedback and available technologies all influenced the choices of the five indexes ultimately utilized. This paper will describe and comment on the strengths and weaknesses of the various indexing approaches taken to access the images within this database.     

数字表面模型(DSM)参数指示林窗特征的有效性研究

林窗的空间格局不仅对林下物种多样性有重要作用,而且也是量化不同林型结构特征的重要指标.近年来,灵活便捷的小型无人机航拍技术的快速发展为获取高分辨率的森林冠层三维结构信息提供了可低成本获取的途径.利用航拍影像提取林窗斑块来计算景观指数是描述林窗格局有效的传统方法,但提取细小林窗往往难度大,尤其是在需要处理大量航拍数据时会...     

从四个类比看如何建立高质量、易维护的用例(Use Case)模型

用例模型在软件开发中占有重要的地位。类和用例都属于类元范畴,具有可比性。该文通过4个类比,由一般较熟悉的,应用于低粒度类设计中的技术、方法和原则过渡到应用于高粒度用例建模的技术、方法和原则,并进一步结合它们给出了用例建模过程的一般步骤。     

Model Selection in an Information Economy: Choosing What to Learn

As online markets for the exchange of goods and services become more common, the study of markets composed, at least in part, of autonomous agents has taken on increasing importance. In contrast to traditional complete–information economic scenarios, agents that are operating in an electronic marketplace often do so under considerable uncertainty. In order to reduce their uncertainty, these agents must learn about the world around them. When an agent producer is engaged in a learning task in which data collection is costly, such as learning the preferences of a consumer population, it is faced with a classic decision problem: when to explore and when to exploit. If the agent has a limited number of chances to experiment, it must explicitly consider the cost of learning (in terms of foregone profit) against the value of the information acquired. Information goods add an additional dimension to this problem; due to their flexibility, they can be bundled and priced according to a number of different price schedules. An optimizing producer should consider the profit each price schedule can extract, as well as the difficulty of learning of this schedule. In this paper, we demonstrate the tradeoff between complexity and profitability for a number of common price schedules. We begin with a one–shot decision as to which schedule to learn. Schedules with moderate complexity are preferred in the short and medium term, as they are learned quickly, yet extract a significant fraction of the available profit. We then turn to the repeated version of this one–shot decision and show that moderate complexity schedules, in particular two–part tariff, perform well when the producer must adapt to nonstationarity in the consumer population. When a producer can dynamically change schedules as it learns, it can use an explicit decision–theoretic formulation to greedily select the schedule which appears to yield the greatest profit in the next period. By explicitly considering both the learnability and the profit extracted by different price schedules, a producer can extract more profit as it learns than if it naively chose models that are accurate once learned.     

Integrating Refined Kano Model,Quality Function Deployment,and Grey Relational Analysis to Improve Service Quality of Nursing Homes

Because of the aging trend in Taiwan, long‐term care plays an important role in the medical system. Finding ways to ensure medical and service quality in long‐term care facilities requires immediate attention. This study discusses service quality in nursing homes and the factors that affect service quality in Taiwan in a way that benefits the management of these organizations. Using a refined Kano model analysis, 12 high value‐added qualities, 4 low value‐added qualities, 1 critical quality, 6 required qualities, 1 potential quality, and 2 care‐free qualities were found. Furthermore, using a combination of quality function deployment and Grey relational analysis (GRA), it was found that medical service standards of the nursing homes require improvement. Items such as “educational training,'' “professional capability,” “degree of understanding patients,” “communication skills,” and “crisis management ability” were provided by an equal‐weight GRA. The improvement sequence was “educational training,” “professional capability,” “communication skills,” “understanding of patients,” and “crisis management ability” in an equal‐weight quantified GRA. The research results can provide nursing homes with an improvement sequence for service design and operational management. © 2012 Wiley Periodicals, Inc.     

Going Beyond Telecenters to Foster the Digital Inclusion of Older People in Brazil: Lessons Learned from a Rapid Ethnographical Study

Telecenters take on a prominent role within the current information and communications technology (ICT) ecosystem in Brazil. They are seen by a great many as a key means to foster the digital inclusion of the older population in the country. This paper draws upon a rapid ethnographic study conducted with 78 older people in a center that teaches computer classes to seniors in Brazil. The results show that providing older people with technological infrastructures is not enough to strengthen their digital inclusion if their basic and non-instrumental needs are not taken into consideration in defining educational activities to be carried out in public centers. Participants’ basic needs when it comes to interacting with ICT, such as coping with accessibility issues, were dynamic, whilst non-instrumental needs, fulfilled by using these technologies, such as interacting with relevant others, remained fairly constant throughout the study. Drawing on the results of the study, strategies for fostering the digital inclusion and well-being of older people in Brazil that go beyond telecenters are suggested.     

The Decoupling of Value Creation from Revenue: A Strategic Analysis of the Markets for Pure Information Goods

Information and telecommunications technologies have profoundly altered the distribution channels available for a wide range of goods and services. In this paper we analyze a particular class of products, information goods and develop a first framework for predicting which information goods are most likely to see their production, distribution, and consumption patterns altered by the net, which are likely to see shifts in power and profitability, and which are likely to remain unchanged for the foreseeable future. We focus on music and news as a selected couple of very different information goods industries that follow two very different trajectories. Our results suggest that the power structure in news distribution is unlikely to be transformed rapidly. In contrast, the power structure in music is transforming rapidly. Star acts no longer need their record labels to certify their music to their fans, and digital production and distribution have reduced or eliminated the value of other assets owned by the record companies. The framework we use to analyze these two industries can readily be applied to a range of others ... from the production of television soap opera series to the publication of academic journals in polymer chemistry.     

How to Verify a Safe Real-Time System: The Application of Model Checking and Timed Automata to the Production Cell Case Study*

The formal verification of a real-time system requires either a proof theoretic or model theoretic approach. Both being applicable to a model of the proposed behavior of the concurrent real-time system. This paper evaluates the use model checking and timed automata by their application to an adaptation of the Production Cell case study. The Uppaal tool is used in this evaluation. The modeling aspects were found to be straightforward, but to accomplish the necessary model checking required some knowledge of the underlying process. Nevertheless, the conclusion of the study is that these techniques are generally applicable and be can be undertaken in an engineering context without detailed domain knowledge of the model checking technique.     

Semi-automatic classification of tree species in different forest ecosystems by spectral and geometric variables derived from Airborne Digital Sensor (ADS40) and RC30 data

This study presents an approach for semi-automated classification of tree species in different types of forests using first and second generation ADS40 and RC30 images from two study areas located in the Swiss Alps. In a first step, high-resolution canopy height models (CHMs) were generated from the ADS40 stereo-images. In a second step, multi-resolution image segmentation was applied. Based on image segments seven different tree species for study area 1 and four for study area 2 were classified by multinomial regression models using the geometric and spectral variables derived from the ADS40 and RC30 images. To deal with the large number of explanatory variables and to find redundant variables, model diagnostics and step-wise variable selection were evaluated. Classifications were ten-fold cross-validated for 517 trees that had been visited in field surveys and detected in the ADS40 images. The overall accuracies vary between 0.76 and 0.83 and Cohen's kappa values were between 0.70 and 0.73. Lower accuracies (kappa < 0.5) were obtained for small samples of species such as non-dominant tree species or less vital trees with similar spectral properties. The usage of NIR bands as explanatory variables from RC30 or from the second generation of ADS40 was found to substantially improve the classification results of the dominant tree species. The present study shows the potential and limits of classifying the most frequent tree species in different types of forests, and discusses possible applications in the Swiss National Forest Inventory.     

基于遥感数据SOFM 网络分类结果的城市增长潜力模型研究——以北京1994～2003年城市扩展为例

在长时间序列多光谱遥感数据和高精度自组织神经网络分类方法的支持下, 对北京地区1994～ 2003 年城市化的基本过程进行了分析和研究, 5 种地物分类结果表明: 北京近10 年来城市扩展基本是以老城为中心围绕环线不断向外围扩展, 呈现一个中心多个环线的发展趋势。在此基础上建立了潜力模型, 计算潜力指数和生成潜力指数图, 潜力指数图呈现从四环以内向外围环线不断递增的趋势, 说明北京市发展主要是农业用地发展为城市用地类型, 这与北京北部2000 年～ 2003年航空照片反映的变化规律一致, 同时还介绍了利用潜力指数对2003 年～ 2012 年城市增长潜力的预测分析。     

Corrigendum to the paper ‘Linear Time Varying Model Predictive Control and its Application to Active Steering Systems: Stability Analysis and Experimental Validation’ (International Journal of Robust and Nonlinear Control 2008; 18(8):862–875)

This note is a corrigendum of the paper ‘Linear Time Varying Model Predictive Control and its Application to Active Steering Systems: Stability Analysis and Experimental Validation’, published on the volume 18, issue 8, pages 862–875 of the International Journal of Robust and Nonlinear Control in 2008. Next we point out a technical error in the proof of Lemma 2 of the paper, and provide the corrected version of the lemma. Copyright © 2011 John Wiley & Sons, Ltd.