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
Background: Maxillofacial war injuries usually cause severe facial organ defects and deformities, handicapping the patient's daily activities, even result in a tendency to commit suicide. The application of maxill...Background: Maxillofacial war injuries usually cause severe facial organ defects and deformities, handicapping the patient's daily activities, even result in a tendency to commit suicide. The application of maxillofacial prosthesis is an alternative to surgery in functional–aesthetic facial reconstruction. Computer aided design and computer aided manufacturing has opened up a new approach to the fabrication of maxillofacial prosthesis. An intelligentized rapid simulative design and manufacture system for prosthesis was developed to facilitate the prosthesis fabrication procedure.Methods: Maxillofacial prosthesis rapid simulation design and rapid fabrication system consists of three components: digital impression, intelligentized prosthesis designing, and rapid manufacturing. The patients' maxillofacial digital impressions were taken with Structured-light 3D scanner; and then the 3D model of prostheses and their negative molds could be designed in specific software; finally, with the resin molds fabricated by rapid prototyping machine, the prostheses could be produced directly and quickly.Results: Fifteen patients of maxillofacial defect caused by traumatic injuries received prosthesis rehabilitation provided by the established system. The contour of the prostheses coordinated properly with the appearance of the patients, and the uniform-thickness border sealed well to adjacent tissues. All the patients were satisfied with their prostheses.Conclusions: The rapid simulative rehabilitation system of maxillofacial defects has been approaching completion. It could provide advanced technological reservation for the Army in the issue of maxillofacial defect rehabilitation.展开更多
Software defect prevention is an important way to reduce the defect introduction rate.As the primary cause of software defects,human error can be the key to understanding and preventing software defects.This paper pro...Software defect prevention is an important way to reduce the defect introduction rate.As the primary cause of software defects,human error can be the key to understanding and preventing software defects.This paper proposes a defect prevention approach based on human error mechanisms：DPe HE.The approach includes both knowledge and regulation training in human error prevention.Knowledge training provides programmers with explicit knowledge on why programmers commit errors,what kinds of errors tend to be committed under different circumstances,and how these errors can be prevented.Regulation training further helps programmers to promote the awareness and ability to prevent human errors through practice.The practice is facilitated by a problem solving checklist and a root cause identification checklist.This paper provides a systematic framework that integrates knowledge across disciplines,e.g.,cognitive science,software psychology and software engineering to defend against human errors in software development.Furthermore,we applied this approach in an international company at CMM Level 5 and a software development institution at CMM Level 1 in the Chinese Aviation Industry.The application cases show that the approach is feasible and effective in promoting developers＇ ability to prevent software defects,independent of process maturity levels.展开更多
Although defect engineering opens up new opportunities in the field of gas sensors,the introduction of defects to enhance the gas sensing properties of metal oxide semiconductors(MOSs)has long been neglected.In this r...Although defect engineering opens up new opportunities in the field of gas sensors,the introduction of defects to enhance the gas sensing properties of metal oxide semiconductors(MOSs)has long been neglected.In this review,defect engineering strategies have been systematically introduced,with a focus on employing them for improved gas sensing performances.To keep the subject focused,we take SnO_(2) nanomaterials as an example.Various synthesis methods for defective SnO_(2),including ion/electron/ray/laser-beam irradiation,plasma treatment,heating protocol,chemical reduction,tailoring specially exposed crystal facets and atoms doping,are emphasized.Different roles of defects on the gas sensing process of SnO_(2) are discussed.Finally,critical issues and future directions of defect engineering are presented.This paper provides a platform for better understanding the relationships between synthesis,defect types and gas sensing performances of MOSs.It is also expected to unpack an important research direction for controlled synthesis of defective nanomaterials with other applications,including advanced energy conversion and storage.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.
基金funded by National Natural Science Foundation of China (81271188)supported by National Key Technology R&D Program of China (2012BAI07B02)
文摘Background: Maxillofacial war injuries usually cause severe facial organ defects and deformities, handicapping the patient's daily activities, even result in a tendency to commit suicide. The application of maxillofacial prosthesis is an alternative to surgery in functional–aesthetic facial reconstruction. Computer aided design and computer aided manufacturing has opened up a new approach to the fabrication of maxillofacial prosthesis. An intelligentized rapid simulative design and manufacture system for prosthesis was developed to facilitate the prosthesis fabrication procedure.Methods: Maxillofacial prosthesis rapid simulation design and rapid fabrication system consists of three components: digital impression, intelligentized prosthesis designing, and rapid manufacturing. The patients' maxillofacial digital impressions were taken with Structured-light 3D scanner; and then the 3D model of prostheses and their negative molds could be designed in specific software; finally, with the resin molds fabricated by rapid prototyping machine, the prostheses could be produced directly and quickly.Results: Fifteen patients of maxillofacial defect caused by traumatic injuries received prosthesis rehabilitation provided by the established system. The contour of the prostheses coordinated properly with the appearance of the patients, and the uniform-thickness border sealed well to adjacent tissues. All the patients were satisfied with their prostheses.Conclusions: The rapid simulative rehabilitation system of maxillofacial defects has been approaching completion. It could provide advanced technological reservation for the Army in the issue of maxillofacial defect rehabilitation.
文摘Software defect prevention is an important way to reduce the defect introduction rate.As the primary cause of software defects,human error can be the key to understanding and preventing software defects.This paper proposes a defect prevention approach based on human error mechanisms：DPe HE.The approach includes both knowledge and regulation training in human error prevention.Knowledge training provides programmers with explicit knowledge on why programmers commit errors,what kinds of errors tend to be committed under different circumstances,and how these errors can be prevented.Regulation training further helps programmers to promote the awareness and ability to prevent human errors through practice.The practice is facilitated by a problem solving checklist and a root cause identification checklist.This paper provides a systematic framework that integrates knowledge across disciplines,e.g.,cognitive science,software psychology and software engineering to defend against human errors in software development.Furthermore,we applied this approach in an international company at CMM Level 5 and a software development institution at CMM Level 1 in the Chinese Aviation Industry.The application cases show that the approach is feasible and effective in promoting developers＇ ability to prevent software defects,independent of process maturity levels.
基金supported by the National Natural Science Foundation of China(No.51872173)the Taishan Scholars Program of Shandong Province,China(No.tsqn201812068)+3 种基金the Opening Fund of State Key Laboratory of Heavy Oil Processing,China(No.SKLOP202002006)the Higher School Youth Innovation Team of Shandong Province,China(No.2019KJA013)the Science and Technology Special Project of Qingdao City,Shandong Province,China(No.20-3-4-3-nsh)financial support provided by the Natural Science Foundation of Shandong Province,China(No.ZR2021QE092).
文摘Although defect engineering opens up new opportunities in the field of gas sensors,the introduction of defects to enhance the gas sensing properties of metal oxide semiconductors(MOSs)has long been neglected.In this review,defect engineering strategies have been systematically introduced,with a focus on employing them for improved gas sensing performances.To keep the subject focused,we take SnO_(2) nanomaterials as an example.Various synthesis methods for defective SnO_(2),including ion/electron/ray/laser-beam irradiation,plasma treatment,heating protocol,chemical reduction,tailoring specially exposed crystal facets and atoms doping,are emphasized.Different roles of defects on the gas sensing process of SnO_(2) are discussed.Finally,critical issues and future directions of defect engineering are presented.This paper provides a platform for better understanding the relationships between synthesis,defect types and gas sensing performances of MOSs.It is also expected to unpack an important research direction for controlled synthesis of defective nanomaterials with other applications,including advanced energy conversion and storage.
