Design patterns are object oriented software design practices for solving common design problems and they affect software quality. In this study, we investigate the relationship of design patterns and software defects...Design patterns are object oriented software design practices for solving common design problems and they affect software quality. In this study, we investigate the relationship of design patterns and software defects in a number of open source software projects. Design pattern instances are extracted from the source code repository of these open source software projects. Software defect metrics are extracted from the bug tracking systems of these projects. Using correlation and regression analysis on extracted data, we examine the relationship between design patterns and software defects. Our findings indicate that there is little correlation between the total number of design pattern instances and the number of defects. However, our regression analysis reveals that individual design pattern instances as a group have strong influences on the number of defects. Furthermore, we find that the number of design pattern instances is positively correlated to defect priority. Individual design pattern instances may have positive or negative impacts on defect priority.展开更多
Jinping I hydropower station is one of the most challenging projects in China due to its highest arch dam and complex geological conditions for construction.After geological investigation into the dam foundation,a few...Jinping I hydropower station is one of the most challenging projects in China due to its highest arch dam and complex geological conditions for construction.After geological investigation into the dam foundation,a few large-scale weak discontinuities are observed.The rock masses in the left dam foundation are intensively unloaded,approximately to the depth of 150–300 m.These serious geological defects lead to a geological asymmetry on the left and right banks,and thus some major diffculties of dam construction are encountered.In this paper,the influences of geological defects on the project are analyzed,followed by the concepts and methods of treatment design.Based on the analysis,the treatment methods of the weak rock masses and discontinuities are carefully determined,including the concrete cushion,concrete replacement grids,and consolidation grouting.They work together to enhance the strength and integrity of the dam foundation.Evaluations and calibrations through geo-mechanical model tests in combination with feld monitoring results in early impoundment period show that the arch dam and its foundation are roughly stable,suggesting that the treatment designs are reasonable and effective.The proposed treatment methods and concepts in the context can be helpful for similar complex rock projects.展开更多
We investigate an optical compact triplexer based on two photonic crystal waveguides and resonant cavities. For performing wavelength selection, we use three core-shell rods as the resonant cavities. The core rods are...We investigate an optical compact triplexer based on two photonic crystal waveguides and resonant cavities. For performing wavelength selection, we use three core-shell rods as the resonant cavities. The core rods are created by introducing air holes in the center of the silicon rods. By varying the radii of the air holes, three specific wavelengths 1.31, 1.49 and 1.55μm can be obtained. This structure is designed and its performance is verified by the finite-difference time-domain method, which is highly suitable for photonic integrated circuits （PICs）. The average output transmission efficiency and quality factor are more than 98.85% and 560, respectively. The mean value of the crosstalk between output channels is about -36.49 dB. The present device is extremely compact with total size 96.24μm2, which is suitable for PICs and can be utilized in the fiber-to-the-home system.展开更多
文摘Design patterns are object oriented software design practices for solving common design problems and they affect software quality. In this study, we investigate the relationship of design patterns and software defects in a number of open source software projects. Design pattern instances are extracted from the source code repository of these open source software projects. Software defect metrics are extracted from the bug tracking systems of these projects. Using correlation and regression analysis on extracted data, we examine the relationship between design patterns and software defects. Our findings indicate that there is little correlation between the total number of design pattern instances and the number of defects. However, our regression analysis reveals that individual design pattern instances as a group have strong influences on the number of defects. Furthermore, we find that the number of design pattern instances is positively correlated to defect priority. Individual design pattern instances may have positive or negative impacts on defect priority.
文摘Jinping I hydropower station is one of the most challenging projects in China due to its highest arch dam and complex geological conditions for construction.After geological investigation into the dam foundation,a few large-scale weak discontinuities are observed.The rock masses in the left dam foundation are intensively unloaded,approximately to the depth of 150–300 m.These serious geological defects lead to a geological asymmetry on the left and right banks,and thus some major diffculties of dam construction are encountered.In this paper,the influences of geological defects on the project are analyzed,followed by the concepts and methods of treatment design.Based on the analysis,the treatment methods of the weak rock masses and discontinuities are carefully determined,including the concrete cushion,concrete replacement grids,and consolidation grouting.They work together to enhance the strength and integrity of the dam foundation.Evaluations and calibrations through geo-mechanical model tests in combination with feld monitoring results in early impoundment period show that the arch dam and its foundation are roughly stable,suggesting that the treatment designs are reasonable and effective.The proposed treatment methods and concepts in the context can be helpful for similar complex rock projects.
文摘We investigate an optical compact triplexer based on two photonic crystal waveguides and resonant cavities. For performing wavelength selection, we use three core-shell rods as the resonant cavities. The core rods are created by introducing air holes in the center of the silicon rods. By varying the radii of the air holes, three specific wavelengths 1.31, 1.49 and 1.55μm can be obtained. This structure is designed and its performance is verified by the finite-difference time-domain method, which is highly suitable for photonic integrated circuits （PICs）. The average output transmission efficiency and quality factor are more than 98.85% and 560, respectively. The mean value of the crosstalk between output channels is about -36.49 dB. The present device is extremely compact with total size 96.24μm2, which is suitable for PICs and can be utilized in the fiber-to-the-home system.
