OCL约束验证与实现的方法

为了能在运行时验证OCL约束,提出了约束验证框架.针对OCL-Java代码(即OCL约束对应的可执行Java代码)插入的简单方案和封装方法存在的不足,给出了改进的代码插入方案,其中应用异常处理技术从而能够捕获冲突的约束.为了使OCL-Java代码根据设计的代码模式插入到Java程序中,对Java解析器作了修改.最后,实验结果表明了该方法的可行性.     

Pseudo software: A mediating instrument for modeling software requirements

A new synthesis of software requirements models called pseudo software is proposed with the aim to cut requirements-related errors. Pseudo software achieves this aim by serving as a mediating instrument to empower stakeholders to participate in requirements elicitation and validation through model construction and manipulation, and to provide guidance to the development team to correctly interpret the requirements in the downstream development activities. Pseudo software obtains its traits as a mediating instrument through the choice of requirements information bits and the use of multimodal representations with tool support to integrate the requirements. Using historical data of fifty projects in the enterprise computing domain, pseudo software is shown to effectively cut the requirements-related errors committed by both the customer and the development team.     

基于龙芯IP核SoC芯片的FPGA验证技术研究

阐述了片上系统(SoC)设计的发展情况和现场可编程门阵列(FPGA)的独特优势,为基于龙芯I号处理器IP核的SoC设计了FPGA验证平台,并介绍了怎样利用该平台进行软硬件协同设计、SoC系统移植、IP核验证和运行实时操作系统。     

基于Agent的网络新闻信息管理系统功能分析

该文从网络新闻信息管理现状出发,结合Agent技术的特性,通过对基于Agent的信息管理系统设计理念的分析,总结并归纳了基于使用者角度的Agent网络新闻信息管理系统三大功能需求;随之,就系统的四个功能模块进行了详细阐述,最后进行系统的兼容性分析。     

Innovative product design based on customer requirement weight calculation model

In the processes of product innovation and design, it is important for the designers to find and capture customer's focus through customer requirement weight calculation and ranking. Based on the fuzzy set theory and Euclidean space distance, this paper puts forward a method for customer requirement weight calculation called Euclidean space distances weighting ranking method. This method is used in the fuzzy analytic hierarchy process that satisfies the additive consistent fuzzy matrix. A model for the weight calculation steps is constructed; meanwhile, a product innovation design module on the basis of the customer requirement weight calculation model is developed. Finally, combined with the instance of titanium sponge production, the customer requirement weight calculation model is validated. By the innovation design module, the structure of the titanium sponge reactor has been improved and made innovative.     

北京数字信息设施使用者需求分析

在数字北京信息设施研究中,将"人种志"的研究方法引入设计中,通过对用户的行为观察和访谈,对人群进行分类,找到用户需求,从而有效地提出针对设计的问题。本文主要对数字北京信息设施使用者的需求进行调研,分析,分类,以及划分层次,从而帮助设计师从使用者的角度去思考设计,不仅可以从纷杂的现象中发现问题,也可以有层次,有步骤地解决问题。     

用于成品率分析芯片的LVS方法

研究成品率分析芯片的特点和设计流程,提出适用的LVS方法。该方法结合传统的LVS及形式验证,能够解决成品率分析芯片中违反设计规则、版图和电路图不匹配等特殊结构的验证问题。将该方法与传统验证流程相融合,用于成品率分析芯片的设计和验证。实验结果证明,成品率分析芯片验证流程具有正确性和稳定性。     

Impact of orthorectification and spatial sampling on maximum NDVI composite data in mountain regions

Topography and accuracy of image geometric registration significantly affect the quality of satellite data, since pixels are displaced depending on surface elevation and viewing geometry. This effect should be corrected for through the process of accurate image navigation and orthorectification in order to meet the geolocation accuracy for systematic observations specified by the Global Climate Observing System (GCOS) requirements for satellite climate data records. We investigated the impact of orthorectification on the accuracy of maximum Normalized Difference Vegetation Index (NDVI) composite data for a mountain region in north-western Canada at various spatial resolutions (1 km, 4 km, 5 km, and 8 km). Data from AVHRR on board NOAA-11 (1989 and 1990) and NOAA-16 (2001, 2002, and 2003) processed using a system called CAPS (Canadian AVHRR Processing System) for the month of August were considered. Results demonstrate the significant impact of orthorectification on the quality of composite NDVI data in mountainous terrain. Differences between orthorectified and non-orthorectified NDVI composites (ΔNDVI) adopted both large positive and negative values, with the 1% and 99% percentiles of ΔNDVI at 1 km resolution spanning values between − 0.16 < ΔNDVI < 0.09. Differences were generally reduced to smaller numbers for coarser resolution data, but systematic positive biases for non-orthorectified composites were obtained at all spatial resolutions, ranging from 0.02 (1 km) to 0.004 (8 km). Analyzing the power spectra of maximum NDVI composites at 1 km resolution, large differences between orthorectified and non-orthorectified AVHRR data were identified at spatial scales between 4 km and 10 km. Validation of NOAA-16 AVHRR NDVI with MODIS NDVI composites revealed higher correlation coefficients (by up to 0.1) for orthorectified composites relative to the non-orthorectified case. Uncertainties due to the AVHRR Global Area Coverage (GAC) sampling scheme introduce an average positive bias of 0.02 ± 0.03 at maximum NDVI composite level that translates into an average relative bias of 10.6% ± 19.1 for sparsely vegetated mountain regions. This can at least partially explain the systematic average positive biases we observed relative to our results in AVHRR GAC-based composites from the Global Inventory Modeling and Mapping Studies (GIMMS) and Polar Pathfinder (PPF) datasets (0.19 and 0.05, respectively). With regard to the generation of AVHRR long-term climate data records, results suggest that orthorectification should be an integral part of AVHRR pre-processing, since neglecting the terrain displacement effect may lead to important biases and additional noise in time series at various spatial scales.     

Managing requirements specifications for product lines - An approach and industry case study

Software product line development has emerged as a leading approach for software reuse. This paper describes an approach to manage natural-language requirements specifications in a software product line context. Variability in such product line specifications is modeled and managed using a feature model. The proposed approach has been introduced in the Swedish defense industry. We present a multiple-case study covering two different product lines with in total eight product instances. These were compared to experiences from previous projects in the organization employing clone-and-own reuse. We conclude that the proposed product line approach performs better than clone-and-own reuse of requirements specifications in this particular industrial context.     

A comparison of tools for teaching formal software verification

We compare four tools regarding their suitability for teaching formal software verification, namely the Frege Program Prover, the Key system, Perfect Developer, and the Prototype Verification System (PVS). We evaluate them on a suite of small programs, which are typical of courses dealing with Hoare-style verification, weakest preconditions, or dynamic logic. Finally we report our experiences with using Perfect Developer in class.