Background. Solving the class-imbalance problem of within-project software defect prediction (SDP) is an important research topic. Although some class-imbalance learning methods have been presented, ...there exists room for improvement. For cross-project SDP, we found that the class-imbalanced source usually leads to misclassification of defective instances. However, only one work has paid attention to this cross-project class-imbalance problem. Objective. We aim to provide effective solutions for both within-project and cross-project class-imbalance problems. Method. Subclass discriminant analysis (SDA), an effective feature learning method, is introduced to solve the problems. It can learn features with more powerful classification ability from original metrics. For within-project prediction, we improve SDA for achieving balanced subclasses and propose the improved SDA (ISDA) approach. For cross-project prediction, we employ the semi-supervised transfer component analysis (SSTCA) method to make the distributions of source and target data consistent, and propose the SSTCA+ISDA prediction approach. Results. Extensive experiments on four widely used datasets indicate that: 1) ISDA-based solution performs better than other state-of-the-art methods for within-project class-imbalance problem; 2) SSTCA+ISDA proposed for cross-project class-imbalance problem significantly outperforms related methods. Conclusion. Within-project and cross-project class-imbalance problems greatly affect prediction performance, and we provide a unified and effective prediction framework for both problems.
ABSTRACT
China's economic reforms over the past three decades have dramatically changed the mechanisms for allocating goods and labour in both market and non‐market spheres. This article examines the ...social and economic trends that intensify the pressure on the care economy, and on women in particular in playing their dual roles as care givers and income earners in post‐reform China. The analysis sheds light on three critical but neglected issues. How does the reform process reshape the institutional arrangements of care for children and elders? How does the changing care economy affect women's choices between paid work and unpaid care responsibilities? And what are the implications of women's work–family conflicts for the well‐being of women and their families? The authors call for a gendered approach to both social and labour market policies, with investments in support of social reproduction services so as to ease the pressures on women.
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•Copper-coated melamine foam was prepared by an electroless plating method.•The PCMs possessed good stiffness-toughness balance and high electro-to-thermal conversion efficiency ...(85.6%).•The PCMs exhibited excellent thermal-induced shape memory property.•The thermal management of electronic devices in hot and cold environments was explored.
Flexible phase change composites (PCMs) show great potential for the thermal management in confined spaces. However, some defects such as low mechanical strength, low thermal/electrical conductivity have limited their advanced applications. In this work, flexible PCMs based on copper-coated melamine foam (MF@Cu) and polyethylene glycol (PEG) were prepared. The MF@Cu foams obtained by electroless copper plating on porous MF were used to encapsulate PEG. Due to the continuous copper network, MF@Cu foams not only enhanced the mechanical loading and encapsulation capacities of PCMs, but also imparted PCMs with electro-to-thermal conversion capability. Moreover, the MF@Cu/PEG PCMs exhibited excellent thermal-induced shape memory property by combining the elasticity of foams and the phase change of PEG. This multifunctional MF@Cu/PEG PCMs were further applied for the thermal management of electronic devices. Therefore, this study provides a strategy to prepare flexible PCMs with excellent integrated performances, which is beneficial to broaden the applications of PCMs.
Multifunctional phase change materials (PCMs) are highly desirable for the thermal management of miniaturized and integrated electronic devices. However, the development of flexible PCMs possessing ...heat energy storage, shape memory, and adjustable electromagnetic interference (EMI) shielding properties under complex conditions remains a challenge. Herein, the multifunctional PCM composites were prepared by encapsulating poly(ethylene glycol) (PEG) into porous MXene/silver nanowire (AgNW) hybrid sponges by vacuum impregnation. Melamine foams (MFs) were chosen as a template to coat with MXene/AgNW (MA) to construct a continuous electrical/thermal conductive network. The MF@MA/PEG composites showed a high latent heat (141.3 J/g), high dimension retention ratio (96.8%), good electrical conductivity (75.3 S/m), and largely enhanced thermal conductivity (2.6 times of MF/PEG). Moreover, by triggering the phase change of the PEG, the sponges displayed a significant photoinduced shape memory function with a high shape fixation ratio (∼100%) and recovery ratio (∼100%). Interestingly, the EMI shielding effectiveness (SE) can be adjusted from 12.4 to 30.5 dB by a facile compression–recovery process based on shape memory properties. Furthermore, a finite element simulation was conducted to emphasize the advantage of the MF@MA/PEG composites in the thermal management of chips. Such flexible PCM composites with high latent heat storage, light-actuated shape memory, and adjustable EMI shielding functions exhibit great potential as smart thermal management materials in military and aerospace applications.
Nitrogen heterocycles have drawn considerable attention due to of their significant biological activities. The marine fungi residing in extreme environments are among the richest sources of these ...basic nitrogen-containing secondary metabolites. As one of the most well-known universal groups of filamentous fungi, marine-derived
species produce a large number of structurally unique heterocyclic alkaloids. This review attempts to provide a comprehensive summary of the structural diversity and biological activities of heterocyclic alkaloids that are produced by marine-derived
species. Herein, a total of 130 such structures that were reported from the beginning of 2014 through the end of 2018 are included, and 75 references are cited in this review, which will benefit future drug development and innovation.
When operating within the environments rich with sodium chloride, steel bars of reinforced concrete structures are often subject to corrosion caused by surrounding erosive materials, and the ...associated rust expansion force due to corrosion takes a critical role in determining the durability of relevant reinforced concrete structures. By investigating the corrosion course of steel reinforcement with theory of elasticity, a numerical rust expansion model is established for the moment of concrete surface rupture based on non-uniform sin function. Cuboid reinforced concrete specimen with squared cross sections is tested to analyze the rust expansion when concrete cracks due to corrosive forces. The utility of the established expansion model is validated by numerical simulation with Abaqus through the comparison between the associated outcomes. The impacts of steel bar diameter and concrete cover thickness on the magnitude of rust expansion force are discussed.
This analysis of the impact of internal migration on the time allocation patterns of the left-behind elderly and children in rural China, 1997–2006, contributes to the literature on changes in the ...well-being of the left-behind population. Based upon the China Health and Nutrition Survey, the multivariate analysis demonstrates that the migration of household members increases the time spent on farm work and domestic work by the left-behind elderly and children. Migration has a striking gender differentiated impact, with the increase in work time being greater for elderly women and girls than elderly men and boys.
Learning an expressive representation from multi-view data is a key step in various real-world applications. In this paper, we propose a semi-supervised multi-view deep discriminant representation ...learning (SMDDRL) approach. Unlike existing joint or alignment multi-view representation learning methods that cannot simultaneously utilize the consensus and complementary properties of multi-view data to learn inter-view shared and intra-view specific representations, SMDDRL comprehensively exploits the consensus and complementary properties as well as learns both shared and specific representations by employing the shared and specific representation learning network. Unlike existing shared and specific multi-view representation learning methods that ignore the redundancy problem in representation learning, SMDDRL incorporates the orthogonality and adversarial similarity constraints to reduce the redundancy of learned representations. Moreover, to exploit the information contained in unlabeled data, we design a semi-supervised learning framework by combining deep metric learning and density clustering. Experimental results on three typical multi-view learning tasks, i.e., webpage classification, image classification, and document classification demonstrate the effectiveness of the proposed approach.
X-linked inhibitor of apoptosis protein (XIAP) possesses a critical role in promotion of cell survival and maintenance of cellular homeostasis. In cancer, elevated XIAP expression has been associated ...with malignancy, poor prognosis, and treatment resistance. However, the underlying mechanisms of these effects remain unclear. XIAP has previously been proposed to promote tumor growth through suppression of autophagy. In this study, we examined the expression of XIAP and p62, two critical mediators of autophagy, in breast and colon cancer. We observed a negative correlation between XIAP and p62 expression in normal and cancer tissues of breast and colon, and that the ratio of XIAP and p62 expression determines the cancer phenotype. In vitro, we observed that XIAP interacted with p62 and also that XIAP depletion resulted in increased expression of p62. XIAP functioned as an ubiquitination E3 ligase towards p62 and suppressed p62 expression through ubiquitin-proteasomal degradation. Furthermore, XIAP enhanced cancer cell proliferation, viability, and colony formation in vitro via suppression of p62. In addition, we demonstrated that XIAP-enhanced tumor growth is dependent on depletion of p62 in vivo. Herein, we have therefore delineated a novel mechanism by which XIAP contributes to development and progression of breast and colon carcinoma.
•Flexible PCM composites were prepared by infiltrating 3D MXene-coated melamine scaffold with PEG.•The PCM composites possessed high phase change enthalpy (194.1 J g−1) and dimension retention ratio ...(90%).•The solar-thermal conversion efficiency was 92.7% with the incorporation of MXene network.•The PCM composites exhibited an excellent light-actuated shape memory performance.•An application of light-driven and flexible heat eye-patch was proposed.
The liquid leakage, low light absorption capability and strong rigidity severely limit large-scale applications of phase change materials (PCMs). In this work, novel PCM composites with good encapsulation property, superior solar-to-thermal conversion efficiency and shape memory function were fabricated by introducing MXene-coated melamine foam (MF@MXene) into poly(ethylene glycol) (PEG). The MF@MXene/PEG composites showed satisfactory dimension retention ratio (90%) and phase change enthalpy (194.1 Jg−1). The three-dimensional MXene network constructed along the MF skeleton imparted the PCM composites with the ability to absorb and store the solar-energy as latent heat. Sunlight irradiation measurements suggested that the solar-thermal conversion efficiency reached 92.7%. Moreover, combining the resilience of MF@MXene sponge and the phase transition of PEG, the PCM composites exhibited remarkable shape fixation and recovery effects. A flexible heat eye-patch was further developed, which could be closely attached on human eyes and provided long-time thermal comfort within a stable temperature range.
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