基于InCoME的软件成本估算方法及支撑工具

软件成本估算领域经过四十余年的发展，涌现出一大批估算理论与方法，但都没有在现实环境中的软件企业中得到广泛应用，在项目早期进行软件成本估算仍旧是一件非常难的任务。由于估算模型的复杂性，缺乏相关的自动化的支撑工具及在现实软件企业中进行成本估算的应用研究是造成这一局面的一个重要原因。 本文从解决现实估算问题出发，提出了基于支撑工具的软件成本估算应用的具体框架。使用专家知识初始化模型，收集历史数据进行模型校准，并使用jack-knife交叉验证对模型进行精度分析。在建立可接受的模型后，收集待估算项目规模和成本因子数据，基于集成成本建模与估算（InCoME）方法，提供COCOMO、类比、回归等多种估算方法的支持。估算结果结合不确定性分析和风险分析，给项目计划和决策提供参考。成本估算应用框架形成一套完整和规范的流程，是一个现实可行的软件成本估算的解决方案。本文的另一贡献在于定制开发此应用框架的支撑工具，即集成成本建模与估算工具。在分析调研主流的软件成本估算工具的基础上，为配合估算应用框架，使用eclipse RCP和关系数据库，开发出层次清晰、可扩展性强、可维护性高、易升级易部署、界面友好的支撑工具。我们将基于支撑工具的软件成本估算应用框架应用于现实中的软件企业进行经验研究，经验研究结果表明，企业的软件成本估算得到了明显改善，支撑工具也被很好的接受。

InCoME软件成本估算工具

针对现行的成本估算软件存在算法支持不够、算法不公开、对建模支持不够等问题,提出了一种基于最优加权算法的集成软件成本估算方法InCoME,并且在此基础上采用Eclipse RCP框架、Java开发语言、HSQLDB关系数据库开发出了In-CoME成本估算软件。该软件不仅实现了驱动因子管理、集成模型支持、模型校准、模型精度分析等模块,而且还实现了基于不确定性的成本估算和风险分析功能,解决了国内一些企业急需成本估算软件等问题。

A data-model fusion approach for upscaling gross ecosystem productivity to the landscape scale based on remote sensing and flux footprint modelling

Chinese Academy of Sciences ; National Science Foundation of China [41071059]; National Key Technology R&D Program of China [2008BAK50B06-02]; National Basic Research Program of China [2010CB950900, 2010CB950704]; Natural Sciences and Engineering Research Council of Canada

Modeling gross primary production of alpine ecosystems in the Tibetan Plateau using MODIS images and climate data

The eddy covariance technique provides measurements of net ecosystem exchange (NEE) Of CO2 between the atmosphere and terrestrial ecosystems, which is widely used to estimate ecosystem respiration and gross primary production (GPP) at a number Of CO2 eddy flux tower sites. In this paper, canopy-level maximum light use efficiency, a key parameter in the satellite-based Vegetation Photosynthesis Model (VPM), was estimated by using the observed CO2 flux data and photosynthetically active radiation (PAR) data from eddy flux tower sites in an alpine swamp ecosystem, an alpine shrub ecosystem and an alpine meadow ecosystem in Qinghai-Tibetan Plateau, China. The VPM model uses two improved vegetation indices (Enhanced Vegetation Index (EVI), Land Surface Water Index (LSWI)) derived from the Moderate Resolution Imaging Spectral radiometer (MODIS) data and climate data at the flux tower sites, and estimated the seasonal dynamics of GPP of the three alpine grassland ecosystems in Qinghai-Tibetan Plateau. The seasonal dynamics of GPP predicted by the VPM model agreed well with estimated GPP from eddy flux towers. These results demonstrated the potential of the satellite-driven VPM model for scaling-up GPP of alpine grassland ecosystems, a key component for the study of the carbon cycle at regional and global scales. (c) 2006 Elsevier Inc. All rights reserved.

Molecular phylogeny, recent radiation and evolution of gross morphology of the rhubarb genus Rheum (Polygonaceae) inferred from chloroplast DNA trnL-F sequences

Background and Aims Rheum, a highly diversified genus with about 60 species, is mainly confined to the mountainous and desert regions of the Qinghai-Tibetan plateau and adjacent areas. This genus represents a good example of the extensive diversification of the temperate genera in the Qinghai-Tibetan plateau, in which the forces to drive diversification remain unknown. To date, the infrageneric classification of Rheum has been mainly based on morphological characters. However, it may have been subject to convergent evolution under habitat pressure, and the systematic position of some sections are unclear, especially Sect. Globulosa, which has globular inflorescences, and Sect. Nobilia, which has semi-translucent bracts. Recent palynological research has found substantial contradictions between exine patterns and the current classification of Rheum. Two specific objectives of this research were (1) to evaluate possible relationships of some ambiguous sections with a unique morphology, and (2) to examine possible occurrence of the radiative speciation with low genetic divergence across the total genus and the correlation between the extensive diversification time of Rheum and past geographical events, especially the recent large-scale uplifts of the Qinghai-Tibetan Plateau.Methods The chloroplast DNA trnL-F region of 29 individuals representing 26 species of Rheum, belonging to seven out of eight sections, was sequenced and compared. The phylogenetic relationships were further constructed based on the sequences obtained.Key Results Despite the highly diversified morphology, the genetic variation in this DNA fragment is relatively low. The molecular phylogeny is highly inconsistent with gross morphology, pollen exine patterns and traditional classifications, except for identifying all samples of Sect. Palmata, three species of Sect. Spiciformia and a few species of Sect. Rheum as corresponding monophyletic groups. The monotypic Sect. Globulosa showed a tentative position within the clade comprising five species of Sect. Rheum. All of the analyses revealed the paraphyly of R. nobile and R. alexandrae, the only two species of Sect. Nobilia circumscribed by the possession of large bracts. The crude calibration of lineages based on trnL-F sequence differentiation implied an extensive diversification of Rheum within approx. 7 million years.Conclusions Based on these results, it is suggested that the rich geological and ecological diversity caused by the recent large-scale uplifts of the Qinghai-Tibetan Plateau since the late Tertiary, coupled with the oscillating climate of the Quaternary stage, might have promoted rapid speciation in small and isolated populations, as well as allowing the fixation of unique or rare morphological characters in Rheum. Such a rapid radiation, combined with introgressive hybridization and reticulate evolution, may have caused the transfer of cpDNA haplotypes between morphologically dissimilar species, and might account for the inconsistency between morphological classification and molecular phylogeny reported here.

Seasonal patterns of gross primary production and ecosystem respiration in an alpine meadow ecosystem on the Qinghai-Tibetan Plateau

We measured the net ecosystem CO2 exchange (NEE) in an alpine meadow ecosystem (latitude 37degrees29'-45'N, longitude 101degrees12'-23'E, 3250 m above sea level) on the Qinghai-Tibetan Plateau throughout 2002 by the eddy covariance method to examine the carbon dynamics and budget on this unique plateau. Diurnal changes in gross primary production (GPP) and ecosystem respiration (R-e) showed that an afternoon increase of NEE was highly associated with an increase of R-e. Seasonal changes in GPP corresponded well to changes in the leaf area index and daily photosynthetic photon flux density. The ratio of GPP/R-e was high and reached about 2.0 during the peak growing season, which indicates that mainly autotrophic respiration controlled the carbon dynamics of the ecosystem. Seasonal changes in mean GPP and R-e showed compensatory behavior as reported for temperate and Mediterranean ecosystems, but those of GPP(max) and R-emax were poorly synchronized. The alpine ecosystem exhibited lower GPP (575 g C m(-2) y(-1)) than, but net ecosystem production (78.5 g C m(-2) y(-1)) similar to, that of subalpine forest ecosystems. The results suggest that the alpine meadow behaved as a CO2 sink during the 1-year measurement period but apparently sequestered a rather small amount of C in comparison with similar alpine ecosystems.