A Convolutional-Transformer Network for Crack Segmentation with Boundary Awareness

Cracks play a crucial role in assessing the safety and durability of manufactured buildings. However, the long and sharp topological features and complex background of cracks make the task of crack segmentation extremely challenging. In this paper, we propose a novel convolutional-transformer network based on encoder-decoder architecture to solve this challenge. Particularly, we designed a Dilated Residual Block (DRB) and a Boundary Awareness Module (BAM). The DRB pays attention to the local detail of cracks and adjusts the feature dimension for other blocks as needed. And the BAM learns the boundary features from the dilated crack label. Furthermore, the DRB is combined with a lightweight transformer that captures global information to serve as an effective encoder. Experimental results show that the proposed network performs better than state-of-the-art algorithms on two typical datasets. Datasets, code, and trained models are available for research at https://github.com/HqiTao/CT-crackseg

Efficient double-quenching of electrochemiluminescence from CdS:Eu QDs by hemin-graphene-Au nanorods ternary composite for ultrasensitive immunoassay

A novel ternary composite of hemin-graphene-Au nanorods (H-RGO-Au NRs) with high electrocatalytic activity was synthesized by a simple method. And this ternary composite was firstly used in construction of electrochemiluminescence (ECL) immunosensor due to its double-quenching effect of quantum dots (QDs). Based on the high electrocatalytic activity of ternary complexes for the reduction of H(2)O(2) which acted as the coreactant of QDs-based ECL, as a result, the ECL intensity of QDs decreased. Besides, due to the ECL resonance energy transfer (ECL-RET) strategy between the large amount of Au nanorods (Au NRs) on the ternary composite surface and the CdS:Eu QDs, the ECL intensity of QDs was further quenched. Based on the double-quenching effect, a novel ultrasensitive ECL immunoassay method for detection of carcinoembryonic antigen (CEA) which is used as a model biomarker analyte was proposed. The designed immunoassay method showed a linear range from 0.01 pg mL(−1) to 1.0 ng mL(−1) with a detection limit of 0.01 pg mL(−1). The method showing low detection limit, good stability and acceptable fabrication reproducibility, provided a new approach for ECL immunoassay sensing and significant prospect for practical application

VLBA 24 and 43 GHz observations of massive binary black hole candidate PKS 1155+251

PKS 1155+251 is a radio-loud quasar source at z=0.203. Observations using very long baseline interferometry (VLBI) at ~2, 5, 8 and 15 GHz show that the structure of the radio source is quite complicated on parsec scales and that the outer hot spots are apparently undergoing a significant contraction. Because these results cannot be fully explained based on the compact symmetric object (CSO) scenario with a radio core located between the northern and southern complexes, we made observations with the Very Long Baseline Array (VLBA) at 24 and 43 GHz to search for compact substructures and alternative interpretations. The results show that the radio core revealed in the previous VLBI observations remains compact with a flat spectrum in our sub-milli-arcsecond--resolution images; the northern lobe emission becomes faint at 24 GHz and is mostly resolving out at 43 GHz; the southern complex is more bright but has been resolved into the brightest southern-end (S1) and jet or tail alike components westwards. Explaining the southern components aligned westward with a standard CSO scenario alone remains a challenge. As for the flatter spectral index of the southern-end component S1 between 24 and 43 GHz in our observations and the significant 15 GHz VLBA flux variability of S1, an alternative scenario is that the southern complex may be powered by a secondary black hole residing at S1. But more sensitive and high-resolution VLBI monitoring is required to discriminate the CSO and the binary black hole scenarios.Comment: 7 pages, 3 figures, accepted by MNRA

An Efficient SDN load balancing scheme based on variance analysis for massive mobile users

In a traditional network, server load balancing is used to satisfy the demand for high data volumes. The technique requires large capital investment while offering poor scalability and flexibility, which difficultly supports highly dynamic workload demands from massive mobile users. To solve these problems, this paper analyses the principle of software-defined networking (SDN) and presents a new probabilistic method of load balancing based on variance analysis. The method can be used to dynamically manage traffic flows for supporting massive mobile users in SDN networks. The paper proposes a solution using the OpenFlow virtual switching technology instead of the traditional hardware switching technology. A SDN controller monitors data traffic of each port by means of variance analysis and provides a probability-based selection algorithm to redirect traffic dynamically with the OpenFlow technology. Compared with the existing load balancing methods which were designed to support traditional networks, this solution has lower cost, higher reliability, and greater scalability which satisfy the needs of mobile users.The work was supported by the National Natural Science Foundation of China (no. 61173188, no. 61572001, and no. 61502008), the Research Fund for the Doctoral Program of Higher Education (no. 20133401110004), the Educational Commission of Anhui Province, China (no. KJ2013A017), the Natural Science Foundation of Anhui Province (no. 1508085QF132), the Tender Project of the Co-Innovation Center for Information Supply & Assurance Technology of Anhui University (no. ADXXBZ2014-7), and the Doctoral Research Startup Funds Project of Anhui University

A load-balancing mechanism for distributed SDN control plane using response time.

Software-Defined Networking (SDN) has become a popular paradigm for managing large-scale networks including cloud servers and data centers because of its advantages of centralized management and programmability. The issues of scalability and reliability that a single centralized controller suffers makes distributed controller architectures emerge. One key limitation of distributed controllers is the statically configured switch-controller mapping, easily causing uneven load distribution among controllers. Previous works have proposed load-balancing methods with switch migration to address this issue. However, the higher-load controller is always directly considered as the overloaded controller that need to shift its load to other controllers, even if it has no response time delay. The pursuit of absolute load-balancing effect can also result in frequent network delays and service interruptions. Additionally, if there are several overloaded controllers, just one controller with the maximum load can be addressed within a single load-balancing operation, reducing load-balancing efficiency. To address these problems, we propose SMCLBRT, a load-balancing strategy of multiple SDN controllers based on response time, considering the changing features of real-time response times versus controller loads. By selecting the appropriate response time threshold and dealing with multiple overloading controllers simultaneously, it can well solve load-balancing problem in SDN control plane with multiple overloaded controllers. Simulation experiments exhibit the effectiveness of our scheme.N/

The effect and molecular mechanism of hypoxia on proliferation and apoptosis of CD133+ renal stem cells

Congenital hydronephrosis caused by ureteropelvic junction obstruction (UPJO) eventually leads to renal interstitial fibrosis and atrophy, after a series of pathophysiological problems. Renal repair after injury depends on renal stem cells. This study aimed to determine the expression of renal stem cell marker CD133 in children of different ages and the regulatory effect of stem cell microenvironment. Renal stem cells from children of different ages were identified and screened out by flow cytometry in the study. Children with hydronephrosis were divided into neonates, infants, preschool age, school age, and adolescents groups. A hypoxic cell model prepared with CoCl2 was developed to detect the effect of hypoxia on the proliferation and apoptosis of renal stem cells. The effect and molecular mechanism of hypoxia-inducible factor 1-alpha (HIF-1α) on the proliferation and apoptosis of renal stem cells were also explored. Both hypoxia and HIF-1α significantly promoted the proliferation of renal stem cells and inhibited cell apoptosis. HIF-1α could bind to the promoter region of proliferating cell nuclear antigen (PCNA) and PROM1 (CD133) to mediate their transcription and expression. The content of CD133+ renal stem cells was the highest in the neonatal group and it decreased with the increase of age. Taken together, this study clarified the effect of age on the content of human renal stem cells and determined the regulatory mechanism of hypoxia on renal stem cells. We expect our results to provide a research basis for the treatment and clinical application of renal stem cells