This paper describes a method of calculating the Schur complement of a sparse positive definite matrix A. The main idea of this approach is to represent matrix A in the form of an elimination tree using a reordering a...This paper describes a method of calculating the Schur complement of a sparse positive definite matrix A. The main idea of this approach is to represent matrix A in the form of an elimination tree using a reordering algorithm like METIS and putting columns/rows for which the Schur complement is needed into the top node of the elimination tree. Any problem with a degenerate part of the initial matrix can be resolved with the help of iterative refinement. The proposed approach is close to the “multifrontal” one which was implemented by Ian Duff and others in 1980s. Schur complement computations described in this paper are available in Intel®Math Kernel Library (Intel®MKL). In this paper we present the algorithm for Schur complement computations, experiments that demonstrate a negligible increase in the number of elements in the factored matrix, and comparison with existing alternatives.展开更多
The paper describes an efficient direct method to solve an equation Ax = b, where A is a sparse matrix, on the Intel®Xeon PhiTM coprocessor. The main challenge for such a system is how to engage all available ...The paper describes an efficient direct method to solve an equation Ax = b, where A is a sparse matrix, on the Intel®Xeon PhiTM coprocessor. The main challenge for such a system is how to engage all available threads (about 240) and how to reduce OpenMP* synchronization overhead, which is very expensive for hundreds of threads. The method consists of decomposing A into a product of lower-triangular, diagonal, and upper triangular matrices followed by solves of the resulting three subsystems. The main idea is based on the hybrid parallel algorithm used in the Intel®Math Kernel Library Parallel Direct Sparse Solver for Clusters [1]. Our implementation exploits a static scheduling algorithm during the factorization step to reduce OpenMP synchronization overhead. To effectively engage all available threads, a three-level approach of parallelization is used. Furthermore, we demonstrate that our implementation can perform up to 100 times better on factorization step and up to 65 times better in terms of overall performance on the 240 threads of the Intel®Xeon PhiTM coprocessor.展开更多
With the increasing importance of cloud services worldwide, the cloud infrastructure and platform management has become critical for cloud service providers. In this paper, a novel architecture of intelligent server m...With the increasing importance of cloud services worldwide, the cloud infrastructure and platform management has become critical for cloud service providers. In this paper, a novel architecture of intelligent server management framework is proposed. In this framework, the communication layer is based on the Extensible Messaging and Presence Protocol (XMPP), which was developed for instant messaging and has been proven to be highly mature and suitable for mobile and large scalable deployment due to its extensibility and efficiency. The proposed architecture can simplify server management and increase flexibility and scalability when managing hundreds of thousands of servers in the cloud era.展开更多
Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face chal...Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.展开更多
Mobile Edge Computing(MEC) is an emerging technology in 5G era which enables the provision of the cloud and IT services within the close proximity of mobile subscribers.It allows the availability of the cloud servers ...Mobile Edge Computing(MEC) is an emerging technology in 5G era which enables the provision of the cloud and IT services within the close proximity of mobile subscribers.It allows the availability of the cloud servers inside or adjacent to the base station.The endto-end latency perceived by the mobile user is therefore reduced with the MEC platform.The context-aware services are able to be served by the application developers by leveraging the real time radio access network information from MEC.The MEC additionally enables the compute intensive applications execution in the resource constraint devices with the collaborative computing involving the cloud servers.This paper presents the architectural description of the MEC platform as well as the key functionalities enabling the above features.The relevant state-of-the-art research efforts are then surveyed.The paper finally discusses and identifies the open research challenges of MEC.展开更多
The effects of Bi addition on the growth of intermetallic compound (IMC) formation in Sn-3.8Ag-0.7Cu solder joints were investigated. The test samples were prepared by conventional surface mounting technology. To inve...The effects of Bi addition on the growth of intermetallic compound (IMC) formation in Sn-3.8Ag-0.7Cu solder joints were investigated. The test samples were prepared by conventional surface mounting technology. To investigate the element diffusion and the growth kinetics of intermetallics formation in solder joint, isothermal aging test was performed at temperatures of 100, 150, and 190℃, respectively. The optical microscope (OM) and scanning electron microscope (SEM) were used to observe microstructure evolution of solder joint and to estimate the thickness and the grain size of the intermetallic layers. The IMC phases were identified by energy dispersive X-ray (EDX) and X-ray diffractometer (XRD). The results clearly show that adding about 1.0% Bi in Sn-Ag-Cu solder alloy system can refine the grain size of the IMC and inhibit the excessive IMC growth in solder joints, and therefore improve the reliability of the Pb-free solder joints. Through observation of the microstructural evolution of the solder joints, the mechanism of inhibition of IMC growth due to Bi addition was proposed.展开更多
Background: Musculoskeletal disorders(MSDs) represent a significant global health burden. While physical activity(PA) and physical fitness are both thought to reduce MSD risk, their independent and joint associations ...Background: Musculoskeletal disorders(MSDs) represent a significant global health burden. While physical activity(PA) and physical fitness are both thought to reduce MSD risk, their independent and joint associations with MSD incidence have not been fully explored. This study investigated the independent and combined effects of PA, cardiorespiratory fitness(CRF), grip strength(GS), and GS asymmetry on MSD incidence in a large prospective cohort.Methods: We analyzed data from the UK Biobank cohort(2006-2023), including 406,080 participants aged 37-73 years(age = 55.7 ± 8.2 years,mean ± SD;53.0% female) who were free of MSD at baseline and during the first 2 years of follow-up. PA, derived from self-reported data and expressed in total metabolic equivalent hours per week(MET-h/week);CRF(watts(W)/kilogram(kg)), measured using a cycling exercise test;and GS(kg), measured by hydraulic hand dynamometer, were included as exposures. GS asymmetry was defined by the left-to-right hand strength ratio. MSD incidence was determined via hospital records. Time-to-event associations were analyzed using Cox proportional hazards regression models with restricted cubic splines to account for non-linear relationships. The analysis was conducted in April 2024.Results: Over a median follow-up of 14.7 years, a total of 73,002 incident cases of MSDs were recorded(rheumatoid arthritis: 2923;osteoarthritis:54,955;degenerative spinal diseases: 15,124). Lower self-reported PA(<4.8 MET-h/week) was associated with increased MSD risk(hazard ratio(HR) = 1.0710, 95% confidence interval(95%CI): 1.0623-1.0797). Low CRF(<1.22 W/kg;HR = 1.0941, 95%CI: 1.0596-1.1298), low GS(<27.80 kg;HR = 1.1133, 95%CI: 1.0990-1.1277), and GS asymmetry(HR = 1.1042, 95%CI: 1.0814-1.1274) were also significantly associated with increased MSD risk. Good CRF and GS, and lower GS asymmetry mitigated the higher MSD risk associated with low PA levels.Conclusion: Low levels of PA, CRF, GS, and GS asymmetry were associated with a higher risk of incident MSD. Meanwhile, improvements in CRF, GS, and GS balance could help offset the risk of MSD incidence in populations with insufficient PA.展开更多
We synthesized NiO-loaded TiO2porous p-n junctions by electrophoretic enhanced micro arc oxidation（EEMAO） technique which is a relatively simple and new method for producing composite coatings.Phase structure,chemic...We synthesized NiO-loaded TiO2porous p-n junctions by electrophoretic enhanced micro arc oxidation（EEMAO） technique which is a relatively simple and new method for producing composite coatings.Phase structure,chemical composition,and surface morphology of the NiO—TiO2coatings were investigated by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,and scanning electron microscopy（SEM） techniques,respectively.Photocatalytic efficiency of the samples was studied through measuring the decomposition rate of 4-chlorophenol under UV irradiation.Results showed that the coatings mainly consisted of anatase,rutile,and nickel oxide phases.It was observed that a finer surface morphology,i.e.smaller pores,was obtained at lower voltages.Besides,the amount of nickel oxide loaded to the TiO2host increased with the voltage.The NiO-TiO2composite coatings showed a higher photoactivity than pure TiO2coatings revealing the effective role of NiO in decreasing the recombination rate of photogenerated electrons and holes.The maximum photocatalytic reaction rate constants for TiO2and NiO—TiO2samples were obtained as 0.0064 and 0.0131 min-1,respectively.We also found that there was an optimum concentration of NiO where a maximum photocatalytic activity was achieved.A correlation between growth variables,structure,and photocatalytic efficiency was established.展开更多
To handle the effects of single event upsets（SEU）,which are common to computers in space radiation environment,a new fault-tolerant system with dual-module redundancy is proposed using dynamic reconfigurable techniq...To handle the effects of single event upsets（SEU）,which are common to computers in space radiation environment,a new fault-tolerant system with dual-module redundancy is proposed using dynamic reconfigurable technique of field programmable gate array（FPGA）. This system contains detection and backup alternative functions,that is,the self-detection and self-healing functions can be completed,and consequently a system design with low hardware redundancy and high resource utilization can be achieved successfully. So it can not only detect fault but also repair the fault effectively after failure. Hence,this method is especially practical to the dynamically reconfigurable computers based on FPGAs. Design methodology has been verified by Virtex-4 FPGA on Xilinx Ml403 development platform.展开更多
文摘This paper describes a method of calculating the Schur complement of a sparse positive definite matrix A. The main idea of this approach is to represent matrix A in the form of an elimination tree using a reordering algorithm like METIS and putting columns/rows for which the Schur complement is needed into the top node of the elimination tree. Any problem with a degenerate part of the initial matrix can be resolved with the help of iterative refinement. The proposed approach is close to the “multifrontal” one which was implemented by Ian Duff and others in 1980s. Schur complement computations described in this paper are available in Intel®Math Kernel Library (Intel®MKL). In this paper we present the algorithm for Schur complement computations, experiments that demonstrate a negligible increase in the number of elements in the factored matrix, and comparison with existing alternatives.
文摘The paper describes an efficient direct method to solve an equation Ax = b, where A is a sparse matrix, on the Intel®Xeon PhiTM coprocessor. The main challenge for such a system is how to engage all available threads (about 240) and how to reduce OpenMP* synchronization overhead, which is very expensive for hundreds of threads. The method consists of decomposing A into a product of lower-triangular, diagonal, and upper triangular matrices followed by solves of the resulting three subsystems. The main idea is based on the hybrid parallel algorithm used in the Intel®Math Kernel Library Parallel Direct Sparse Solver for Clusters [1]. Our implementation exploits a static scheduling algorithm during the factorization step to reduce OpenMP synchronization overhead. To effectively engage all available threads, a three-level approach of parallelization is used. Furthermore, we demonstrate that our implementation can perform up to 100 times better on factorization step and up to 65 times better in terms of overall performance on the 240 threads of the Intel®Xeon PhiTM coprocessor.
文摘With the increasing importance of cloud services worldwide, the cloud infrastructure and platform management has become critical for cloud service providers. In this paper, a novel architecture of intelligent server management framework is proposed. In this framework, the communication layer is based on the Extensible Messaging and Presence Protocol (XMPP), which was developed for instant messaging and has been proven to be highly mature and suitable for mobile and large scalable deployment due to its extensibility and efficiency. The proposed architecture can simplify server management and increase flexibility and scalability when managing hundreds of thousands of servers in the cloud era.
基金financial supports from National Key Research and Development Program of China(2023YFB3209500)National Natural Science Foundation of China(NSFC)(12274052 and 62171076)+1 种基金Fundamental Research Funds for the Central Universities(DUT24ZD203)Bolian Research Funds of Dalian Maritime University and Fundamental Research Funds for the Central Universities(3132024605).
文摘Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.
文摘Mobile Edge Computing(MEC) is an emerging technology in 5G era which enables the provision of the cloud and IT services within the close proximity of mobile subscribers.It allows the availability of the cloud servers inside or adjacent to the base station.The endto-end latency perceived by the mobile user is therefore reduced with the MEC platform.The context-aware services are able to be served by the application developers by leveraging the real time radio access network information from MEC.The MEC additionally enables the compute intensive applications execution in the resource constraint devices with the collaborative computing involving the cloud servers.This paper presents the architectural description of the MEC platform as well as the key functionalities enabling the above features.The relevant state-of-the-art research efforts are then surveyed.The paper finally discusses and identifies the open research challenges of MEC.
文摘The effects of Bi addition on the growth of intermetallic compound (IMC) formation in Sn-3.8Ag-0.7Cu solder joints were investigated. The test samples were prepared by conventional surface mounting technology. To investigate the element diffusion and the growth kinetics of intermetallics formation in solder joint, isothermal aging test was performed at temperatures of 100, 150, and 190℃, respectively. The optical microscope (OM) and scanning electron microscope (SEM) were used to observe microstructure evolution of solder joint and to estimate the thickness and the grain size of the intermetallic layers. The IMC phases were identified by energy dispersive X-ray (EDX) and X-ray diffractometer (XRD). The results clearly show that adding about 1.0% Bi in Sn-Ag-Cu solder alloy system can refine the grain size of the IMC and inhibit the excessive IMC growth in solder joints, and therefore improve the reliability of the Pb-free solder joints. Through observation of the microstructural evolution of the solder joints, the mechanism of inhibition of IMC growth due to Bi addition was proposed.
基金supported by research grants from the National Natural Science Foundation of China(No.82001726,82301768)the National Key Research and Development programme of China(No.2024YFC3405800)+3 种基金Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences(No.2019-I2M-5-066)Scientific Research Foundation provided by Pudong Hospital affiliated to Fudan University(No.YJYJRC202202)The Talents Training Program of Pudong Hospital affiliated to Fudan University(No.YQ202201)the Shanghai Municipal Science and Technology Major Project(No.2023SHZDZX02)。
文摘Background: Musculoskeletal disorders(MSDs) represent a significant global health burden. While physical activity(PA) and physical fitness are both thought to reduce MSD risk, their independent and joint associations with MSD incidence have not been fully explored. This study investigated the independent and combined effects of PA, cardiorespiratory fitness(CRF), grip strength(GS), and GS asymmetry on MSD incidence in a large prospective cohort.Methods: We analyzed data from the UK Biobank cohort(2006-2023), including 406,080 participants aged 37-73 years(age = 55.7 ± 8.2 years,mean ± SD;53.0% female) who were free of MSD at baseline and during the first 2 years of follow-up. PA, derived from self-reported data and expressed in total metabolic equivalent hours per week(MET-h/week);CRF(watts(W)/kilogram(kg)), measured using a cycling exercise test;and GS(kg), measured by hydraulic hand dynamometer, were included as exposures. GS asymmetry was defined by the left-to-right hand strength ratio. MSD incidence was determined via hospital records. Time-to-event associations were analyzed using Cox proportional hazards regression models with restricted cubic splines to account for non-linear relationships. The analysis was conducted in April 2024.Results: Over a median follow-up of 14.7 years, a total of 73,002 incident cases of MSDs were recorded(rheumatoid arthritis: 2923;osteoarthritis:54,955;degenerative spinal diseases: 15,124). Lower self-reported PA(<4.8 MET-h/week) was associated with increased MSD risk(hazard ratio(HR) = 1.0710, 95% confidence interval(95%CI): 1.0623-1.0797). Low CRF(<1.22 W/kg;HR = 1.0941, 95%CI: 1.0596-1.1298), low GS(<27.80 kg;HR = 1.1133, 95%CI: 1.0990-1.1277), and GS asymmetry(HR = 1.1042, 95%CI: 1.0814-1.1274) were also significantly associated with increased MSD risk. Good CRF and GS, and lower GS asymmetry mitigated the higher MSD risk associated with low PA levels.Conclusion: Low levels of PA, CRF, GS, and GS asymmetry were associated with a higher risk of incident MSD. Meanwhile, improvements in CRF, GS, and GS balance could help offset the risk of MSD incidence in populations with insufficient PA.
文摘We synthesized NiO-loaded TiO2porous p-n junctions by electrophoretic enhanced micro arc oxidation（EEMAO） technique which is a relatively simple and new method for producing composite coatings.Phase structure,chemical composition,and surface morphology of the NiO—TiO2coatings were investigated by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,and scanning electron microscopy（SEM） techniques,respectively.Photocatalytic efficiency of the samples was studied through measuring the decomposition rate of 4-chlorophenol under UV irradiation.Results showed that the coatings mainly consisted of anatase,rutile,and nickel oxide phases.It was observed that a finer surface morphology,i.e.smaller pores,was obtained at lower voltages.Besides,the amount of nickel oxide loaded to the TiO2host increased with the voltage.The NiO-TiO2composite coatings showed a higher photoactivity than pure TiO2coatings revealing the effective role of NiO in decreasing the recombination rate of photogenerated electrons and holes.The maximum photocatalytic reaction rate constants for TiO2and NiO—TiO2samples were obtained as 0.0064 and 0.0131 min-1,respectively.We also found that there was an optimum concentration of NiO where a maximum photocatalytic activity was achieved.A correlation between growth variables,structure,and photocatalytic efficiency was established.
基金supported by the National Natural Science Foundation of China under Grant No. 60971036the National High Technology Research and Development Program of China under Grant No. 2008AA01Z104+1 种基金the Fundamental Research Funds for the Central Universities under Grant No. ZYGX2009Z004the New Century Excellent Talents in University under Grant No. NCET-08-0087
文摘To handle the effects of single event upsets（SEU）,which are common to computers in space radiation environment,a new fault-tolerant system with dual-module redundancy is proposed using dynamic reconfigurable technique of field programmable gate array（FPGA）. This system contains detection and backup alternative functions,that is,the self-detection and self-healing functions can be completed,and consequently a system design with low hardware redundancy and high resource utilization can be achieved successfully. So it can not only detect fault but also repair the fault effectively after failure. Hence,this method is especially practical to the dynamically reconfigurable computers based on FPGAs. Design methodology has been verified by Virtex-4 FPGA on Xilinx Ml403 development platform.
