This paper empirically investigates the relationships between 15 design metrics and maintainability of 148 Java open source software. The results show that size and complexity metrics are strongly related to the maint...This paper empirically investigates the relationships between 15 design metrics and maintainability of 148 Java open source software. The results show that size and complexity metrics are strongly related to the maintainability of open source software. However, cohesion and coupling, as currently captured by existing metrics, do not seem to have a significant impact on maintainability. When used together, these metrics can predict system maintainability fairly accurately （mean MREs below 30%）.展开更多
Maintainability prediction is one kind of primary maintainability action. Design deficiency would be found through predicting maintainability parameters under certain conditions. Now a maintainability prediction metho...Maintainability prediction is one kind of primary maintainability action. Design deficiency would be found through predicting maintainability parameters under certain conditions. Now a maintainability prediction method that mainly considers maintenance time or maintenance man hour is a kind of prediction method with a single index. With increasing product complexity and people's environmental consciousness, more attention is paid to environment impacts and maintenance cost or resource consumption in the maintenance process. It is necessary for a maintainability prediction method that can predict maintenance cost and maintenance environmental impacts. A new maintainability prediction method is presented in this paper based on analyzing existing maintainability prediction methods. The method is MABTCE(maintenance activity based timing/costing/environment impact assessment) and can predict maintenance time, maintenance costing and maintenance environmental impacts and then improve maintainability design with prediction results.展开更多
To aim at higher coding efficiency for multiview video coding, the multiview video with a modified high efficiency video coding（MV-HEVC）codec is proposed to encode the dependent views.However, the computational comp...To aim at higher coding efficiency for multiview video coding, the multiview video with a modified high efficiency video coding（MV-HEVC）codec is proposed to encode the dependent views.However, the computational complexity of MV-HEVC encoder is also increased significantly since MV-HEVC inherits all computational complexity of HEVC. This paper presents an efficient algorithm for reducing the high computational complexity of MV-HEVC by fast deciding the coding unit during the encoding process. In our proposal, the depth information of the largest coding units（LCUs） from independent view and neighboring LCUs is analyzed first. Afterwards, the analyzed results are used to early determine the depth for dependent view and thus achieve computational complexity reduction. Furthermore, a prediction unit（PU） decision strategy is also proposed to maintain the video quality. Experimental results demonstrate that our algorithm can achieve 57% time saving on average,while maintaining good video quality and bit-rate performance compared with HTM8.0.展开更多
复杂装备系统结构复杂,运行模式多,导致传统的维修性预计模型无法准确计算出平均修复时间(meantime to repair,MTTR).在分析复杂装备系统维修特点的基础上,提出考虑设备拆卸顺序和系统故障模式的维修性预计模型,并应用CPN建立多层次的...复杂装备系统结构复杂,运行模式多,导致传统的维修性预计模型无法准确计算出平均修复时间(meantime to repair,MTTR).在分析复杂装备系统维修特点的基础上,提出考虑设备拆卸顺序和系统故障模式的维修性预计模型,并应用CPN建立多层次的仿真模型,通过仿真运行获得MTTR.CPN模型中定义了模型变量,通过将计算MTTR的输入参数化,能够保证CPN模型具备广泛的适应性.案例仿真表明所提出的方法具有可行性.展开更多
基金Supported by the National Natural Science Foundation of China (60425206, 60633010)the High Technology Research Project of Jiangsu Province (BG2005032)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060286020)
文摘This paper empirically investigates the relationships between 15 design metrics and maintainability of 148 Java open source software. The results show that size and complexity metrics are strongly related to the maintainability of open source software. However, cohesion and coupling, as currently captured by existing metrics, do not seem to have a significant impact on maintainability. When used together, these metrics can predict system maintainability fairly accurately （mean MREs below 30%）.
文摘Maintainability prediction is one kind of primary maintainability action. Design deficiency would be found through predicting maintainability parameters under certain conditions. Now a maintainability prediction method that mainly considers maintenance time or maintenance man hour is a kind of prediction method with a single index. With increasing product complexity and people's environmental consciousness, more attention is paid to environment impacts and maintenance cost or resource consumption in the maintenance process. It is necessary for a maintainability prediction method that can predict maintenance cost and maintenance environmental impacts. A new maintainability prediction method is presented in this paper based on analyzing existing maintainability prediction methods. The method is MABTCE(maintenance activity based timing/costing/environment impact assessment) and can predict maintenance time, maintenance costing and maintenance environmental impacts and then improve maintainability design with prediction results.
基金supported by NSC under Grant No.NSC 100-2628-E-259-002-MY3
文摘To aim at higher coding efficiency for multiview video coding, the multiview video with a modified high efficiency video coding（MV-HEVC）codec is proposed to encode the dependent views.However, the computational complexity of MV-HEVC encoder is also increased significantly since MV-HEVC inherits all computational complexity of HEVC. This paper presents an efficient algorithm for reducing the high computational complexity of MV-HEVC by fast deciding the coding unit during the encoding process. In our proposal, the depth information of the largest coding units（LCUs） from independent view and neighboring LCUs is analyzed first. Afterwards, the analyzed results are used to early determine the depth for dependent view and thus achieve computational complexity reduction. Furthermore, a prediction unit（PU） decision strategy is also proposed to maintain the video quality. Experimental results demonstrate that our algorithm can achieve 57% time saving on average,while maintaining good video quality and bit-rate performance compared with HTM8.0.
文摘复杂装备系统结构复杂,运行模式多,导致传统的维修性预计模型无法准确计算出平均修复时间(meantime to repair,MTTR).在分析复杂装备系统维修特点的基础上,提出考虑设备拆卸顺序和系统故障模式的维修性预计模型,并应用CPN建立多层次的仿真模型,通过仿真运行获得MTTR.CPN模型中定义了模型变量,通过将计算MTTR的输入参数化,能够保证CPN模型具备广泛的适应性.案例仿真表明所提出的方法具有可行性.
