Simultaneous Graphic Generalization of Vector Data Sets

Manual cartographic generalization is a simultaneous process. However, most automatic approaches so far have been sequential; generalization operators are applied one at a time in a certain order. This has been the case both for model generalization (generalization of the conceptual model) and graphic generalization. Our research seeks to demonstrate that the graphic part of cartographic generalization can be formulated as an optimization problem and accordingly be solved in a single step. This paper deals with several issues regarding this optimization approach. Firstly, a set of appropriate analytical constraints for the generalization process is given, as well as rules for when to apply these constraints. In our approach, we are limited to formulating these constraints on point locations. Secondly, least-squares adjustment is proposed to find the optimal solution according to the constraints. Finally, the conjugate-gradients method is recommended for solving the normal equations. A prototype system for simultaneous graphic generalization has been implemented in C++, which communicates with a commercial map production system. Results from three tests of the prototype system are included in the paper.     

A model-based approach for multiple QoS in scheduling: from models to implementation

Meeting multiple Quality of Service (QoS) requirements is an important factor in the success of complex software systems. This paper presents an automated, model-based scheduler synthesis approach for scheduling application software tasks to meet multiple QoS requirements. As a first step, it shows how designers can meet deadlock-freedom and timeliness requirements, in a manner that (i) does not over-provision resources, (ii) does not require architectural changes to the system, and that (iii) leaves enough degrees of freedom to pursue further properties. A major benefit of our synthesis methodology is that it increases traceability, by linking each scheduling constraint with a specific pair of QoS property and underlying platform execution model, so as to facilitate the validation of the scheduling constraints and the understanding of the overall system behaviour, required to meet further QoS properties.     

GIS环境下制图自动综合

借助GIS的可视化以及GIS的空间分析工具,制图自动综合的研究进入了一个新阶段;一方面,GIS扩大了制图自动综合的内涵,另一方面,制图自动综合推动了GIS的发展;丰富了GIS的研究内容。实际上,制图自动综合应该是GSI系统的重要组成部分或应具有的重要功能。制图自动综合的研究手段和研究方法越来越丰富并取得了很大进展;在总结前人研究的基础上提出了GIS分层支持下的面向地理特征的自动综合,实验表明这种方法是可行的,但仍然存在诸多问题,这种方法的完善必须走基于知识综合的道路。     

SMArDT modeling for automotive software testing

Efficient testing is a crucial prerequisite to engineer reliable automotive software successfully. However, manually deriving test cases from ambiguous textual requirements is costly and error-prone. Model-based software engineering captures requirements in structured, comprehensible, and formal models, which enables early consistency checking and verification. Moreover, these models serve as an indispensable basis for automated test case derivation. To facilitate automated test case derivation for automotive software engineering, we conducted a survey with testing experts of the BMW Group and conceived a method to extend the BMW Group's specification method for requirements, design, and test methodology by model-based test case derivation. Our method is realized for a variant of systems modeling language activity diagrams tailored toward testing automotive software and a model transformation to derive executable test cases. Hereby, we can address many of the surveyed practitioners' challenges and ultimately facilitate quality assurance for automotive software.     

基于C—Tree的无级比例尺GIS多边形综合技术

无级比例尺GIS是数字地球和Web GIS的核心技术之一,但随着GIS的广泛应用和深入发展,现有的GIS技术已经不能满足信息社会的需要,其中一个需要解决的重要问题就是GIS的空间数据量如何随着比例尺的变化自动增减。针对无级比例尺GIS多边形综合中的选取与合并技术,在对选取的数量规律和质量原则以及合并的原则进行充分论述的基础上,提出了一种多边形图层数据组织策略C-Tree,并给出了基于C-Tree的多边形综合算法。对于给定的大给与大比例尺地图多边形图层数据,该算法可以高效率地完成多边形选取与合并的综合操作,输出小比例尺地图图层数据。该算法现已成功应用于时空一体化智能城建信息系统,并获得了满意的结果。     

A two‐step methodology to reduce requirement defects

Defects are introduced into a software product during every phase of software development. A major source of defects that is often overlooked is requirements generation. Requirement errors discovered in later phases of the software development process are the most costly to correct because all phases of software development are usually impacted. Requirement defects can be categorized into two main types: 1) specification generation errors; and 2) unwanted/unnecessary/incorrect user functionality. This experience report presents the results of incorporating a two‐step methodology which combines Operational Demonstrations of the user interface and Requirement Inspections on software requirement specifications. The two‐step methodology addresses and corrects both types of requirement defects. Results from this experience support the premise that cost reduction and quality improvement can be obtained using a combined Operational Demonstration and Requirement Inspection development methodology for software requirements.     

采用案例归纳推理进行道路网智能选取

自动制图综合集技术、艺术与制图人员经验于一体,长期以来其自动化、智能化研究进展缓慢。基于机器学习的智能化自动综合也成为了制图综合发展过程中必须解决而仍未得到很好解决的核心难题之一。本文提出基于案例归纳学习的道路网智能选取方法。该方法以制图专家道路网选取案例库为学习对象,以决策树算法为推理机,从专家案例库中自动归纳、推理来获取决策树,并转化为满足计算机自动执行的规则集,据此来进行道路网自动选取。从而解决了把难以形式化表达的制图专家经验自动转化为满足计算机自动综合要求的规则,并据此进行智能化自动综合这一难题。最后,采用实例对本方法进行了验证,实验结果表明,该方法能够从专家案例库中自动获取核心规则,并进行自动综合,综合结果能够有效地反映制图专家的制图综合经验,同时具有普适性,从而为智能化自动制图综合发展探索了新的途径。     

涉众为中心的敏捷需求建模

提出一种将涉众为中心和敏捷方法有机结合的敏捷需求建模方法。所有软件系统需求获取以涉众为中心,基于涉众扩展特征建立涉众Power/Interest分布图来确定涉众优先级,并用优先级处理不同涉众之间的需求冲突,根据涉众为中心的敏捷需求方法,提出敏捷需求实践方法,融合敏捷方法的短周期、演化、增量、迭代、重构、反馈机制,使软件系统需求建模过程更加完备、精确、高效、快捷,用双变迁Petri网DTPN为该方法建立形式化敏捷需求模型,为软件系统需求建模提出了一种新的方法。     

Automated test generation and evaluation for real-time expert systems

This paper describes a method for automated test generation and evaluation for real-time expert systems. This method supports dynamic testing, where test inputs are generated randomly within the constraints specified by a Test Specification Language. This allows the discovery of “unintended functionalities,” which may not be possible either through static testing or expert-supplied test cases. Automated test generation also allows rapid regeneration of test suites as the system evolves through various prototypes and versions. the Test Specification Language provides constructs for dealing with real-time constraints. Sample specifications and results implemented within the Activation Framework software development tool are also described. © 1994 John Wiley & Sons, Inc.     

Accessible design and testing in the application development process: considerations for an integrated approach

Accessible design principles should permeate virtually all phases of the application development cycle, using existing “best practices of software engineering” for accessibility purposes. This paper proposes a methodology for accessible design and testing that includes proven tools of software engineering, namely use cases and scenarios, to capture functional requirements. Guidelines developed through user testing and heuristics are made real using personas to exemplify accessibility requirements, reflecting a diversity of user capabilities and use contexts. For implementation and testing, test cases containing accessibility checkpoints are generated, based on the guidelines. Complementary to this methodology, expert reviews and user testing should be conducted for evaluation of the developed products and further refinement of the development process.     

图层约束下的点状自然灾害风险地图综合

点状自然灾害现象如地震、滑坡等,由于其特殊性,灾害风险与其周边的地理环境有着复杂的联系和相互作用,孕灾环境对灾情具有放大或缩小的效应,在制图综合过程中,不能只考虑单个灾害点个体,而因将与之相关的各因素综合考虑,从而判定其风险范围。基于此,在地理学与地图学的基础上,从灾害系统的角度考虑,探讨基于图层约束(LC)和模糊推理系统(FIS)相结合的点状现象自动综合的适用性问题,重点阐述基于图层约束理论和FIS算法相结合的滑坡灾害自动综合技术,并以滑坡灾害为例,构建了基于滑坡灾害程度区划、地形坡度、地貌区划、地震长期烈度区划、年暴雨日数、年均降水量等为约束图层的自动综合应用;通过多尺度综合分析结果表明,中国存在三大重点滑坡区:即青藏高原东部斜坡带、黄土高原滑坡区和太行山东麓、巫山、武陵山脉一线滑坡带。本研究为多尺度、多图层约束下的自然灾害风险地图自动综合提供了一种有效途径,同时对不同区域尺度下的灾害风险管理提供了更高效、更准确的决策支持和技术支撑。     

一个支持软件需求测试任务分析方法的工具

需求定义模型测试的任务分析方法，把需求情形实例当作需求模型的测试用例，用任务活动序列描述情形，并提供给任务分析专家和用户进行对照分析。情形实例的活动序列描述以文字的形式描述系统行为的细节，表达清晰，较需求模型更容易被用户所理解。文章介绍支持该方法的一个需求模型测试自动化工具ＳＲＤＭＴｅｓｔ．     

Black box scatter search for general classes of binary optimization problems

The purpose of this paper is to apply the scatter search methodology to general classes of binary problems. We focus on optimization problems for which the solutions are represented as binary vectors and that may or may not include constraints. Binary problems arise in a variety of settings, including engineering design and statistical mechanics (e.g., the spin glass problem). A distinction is made between two sets of general constraint types that are handled directly by the solver and other constraints that are addressed via penalty functions. In both cases, however, the heuristic treats the objective function evaluation as a black box. We perform computational experiments with four well-known binary optimization problems to study the efficiency (speed) and effectiveness (solution quality) of the proposed method. Comparisons are made against both commercial software and specialized procedures on a set of 376 instances. We chose commercial software that is similar in nature to the proposed procedure, namely, it treats the objective function as a black box and the search is based on evolutionary optimization techniques.     

基于任务的舰船装备软件测试技术研究

针对基于任务的舰船装备软件进行测试时,缺乏任务需求的系统化分析与描述手段、难以从任务执行层面有效生成测试用例、不支持跨平台测试的自动化执行等问题,对舰船装备软件任务分析与建模、基于任务模型的舰船装备软件测试用例生成及舰船装备软件测试自动化执行等三方面关键技术进行了研究,研制了配套的软件测试工具,形成了一整套基于任务的舰船装备软件测试技术,以满足基于任务的舰船装备软件测试的需要。在此基础上,开展了基于任务的舰船装备软件测试技术实例应用,验证了该技术的工程适用性和配套工具的有效性,并形成了典型应用实例,为该技术的推广提供支撑。     

Constrained tGAP for generalization between scales: The case of Dutch topographic data

This article presents the results of integrating large- and medium-scale data into a unified data structure. This structure can be used as a single non-redundant representation for the input data, which can be queried at any arbitrary scale between the source scales. The solution is based on the constrained topological Generalized Area Partition (tGAP), which stores the results of a generalization process applied to the large-scale dataset, and is controlled by the objects of the medium-scale dataset, which act as constraints on the large-scale objects. The result contains the accurate geometry of the large-scale objects enriched with the generalization knowledge of the medium-scale data, stored as references in the constraint tGAP structure. The advantage of this constrained approach over the original tGAP is the higher quality of the aggregated maps. The idea was implemented with real topographic datasets from The Netherlands for the large- (1:1000) and medium-scale (1:10,000) data. The approach is expected to be equally valid for any categorical map and for other scales as well.     

Traffic-aware stress testing of distributed real-time systems based on UML models using genetic algorithms

This paper presents a model-driven, stress test methodology aimed at increasing chances of discovering faults related to network traffic in distributed real-time systems (DRTS). The technique uses the UML 2.0 model of the distributed system under test, augmented with timing information, and is based on an analysis of the control flow in sequence diagrams. It yields stress test requirements that are made of specific control flow paths along with time values indicating when to trigger them. The technique considers different types of arrival patterns (e.g., periodic) for real-time events (common to DRTSs), and generates test requirements which comply with such timing constraints. Though different variants of our stress testing technique already exist (that stress different aspects of a distributed system), they share a large amount of common concepts and we therefore focus here on one variant that is designed to stress test the system at a time instant when data traffic on a network is maximal. Our technique uses genetic algorithms to find test requirements which lead to maximum possible traffic-aware stress in a system under test. Using a real-world DRTS specification, we design and implement a prototype DRTS and describe, for that particular system, how the stress test cases are derived and executed using our methodology. The stress test results indicate that the technique is significantly more effective at detecting network traffic-related faults when compared to test cases based on an operational profile.     

基于状态转移图的箭载软件时序控制测试用例生成方法

为提升箭载嵌入式软件测试的效率和质量,本文专门针对箭载软件时序控制这一测试需求,提出了一种基于状态转移图的测试用例自动生成算法设计方法。具体分析步骤为首先分析时序控制特性,其次选取状态转移图来表征,自定义所需图元属性以及图元关系、触发条件全面性与一致性的约束条件从而保证模型合理性；再次采用基路径覆盖、转移对覆盖、条件元覆盖三种覆盖准则相结合方式实现测试用例的自动生成；最后以某箭上软件全飞行周期时序控制为基础,多次结果表明该方法生成的软件测试用例可完全覆盖时序控制功能和性能需求,验证了方法的有效性和稳定性,可为箭载软件自动化测试工程化实践提供一定的借鉴。     

On eliciting requirements from end-users in the ICT4D domain

Currently, there is much interest in harnessing the potential of new and affordable Information and Communication Technologies (ICT) such as mobile phones, to assist in reducing disparities in socioeconomic conditions throughout the world. Such efforts have come to be known as ICT for Development or ICT4D. Although this field of research holds much promise, few projects have managed to achieve long-term sustained success. Among the many reasons for this, from a software engineering perspective, in many cases, it can be attributed to inadequacies in gathering and defining software requirements. Incomplete software requirements and the consequent failures in creating sustainable systems arise because of inadequate consideration of the high-level social development goals, neglect of environmental constraints and/or a lack of adequate input from end-users regarding their specific needs and socio-cultural context. We propose enhancements to the requirements elicitation methodology specifically adapted to address these shortcomings. Our approach incorporates the novel technique of Structured Digital Storytelling to elicit input from end-users who have limited literacy and applies a conceptual model derived from Communications Theory to analyse the constraints that arise from their socio-cultural context. The needs, goals and constraints thus identified are integrated using a goal-based analysis to produce a more informed understanding of the potential areas of technology intervention and the needed software requirements. We illustrate our approach and validate its effectiveness with a field study.     

基于ABTM的城市建筑物合并算法

大比例尺城市建筑物合并算法的研究一直是制图综合的重点。为此,分析了目前面状建筑物合并算法存在的不足,提出了把Agent技术与TIN技术、聚类技术相结合的算法(ABTM),以提高城市建筑物合并的速度、智能化和自动化水平。首先对地图数据进行聚类分析,以对地图数据进行分区域处理;然后把约束Delaunay三角剖分技术运用到本算法中来,提出了一种对Delaunay三角形分类的方法,结合Agent技术,定义了一种以Delaunay三角形为基础的Agent层次概念,并对不同层次的Agent定义了具有生命周期的数据结构。依据Agent的层次结构、TIN图形计算模型和制图综合约束条件,提出了一种基于Agent和TIN技术的建筑物自动合并新算法。最后给出了综合实例,并对结果进行了量化分析。分析结果表明,本算法具有比其他类似算法更高的整体性能。     

A methodology for designing toolkits for specification level verification of interval-constrained information systems requirements

In developing automated tools for verification for an Information systems (IS), there exists a need for a methodology for the development of information requirements maintenance toolkits which will maintain IS with unconstrained and constrained requirements. In this paper, we present a methodology for building generalized designs of IS maintenance toolkits that maintain the requirements specification of IS. Our methodology will decrease the effort in building and increase the structural quality of IS maintenance toolkits that are used for verification of an IS in areas such as command, control, communication, computer, intelligence, surveillance, and reconnaissance (C⁴ISR) organizations. The methodology represents a reuse-oriented Unified Modeling Process (UMP) and consists of a method for developing an enterprise model, a method for developing use cases of the toolkit services, a method for developing logic designs and a method for developing the component view of the software.