As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stor...As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stored energy on localized corrosion evolution in 2A97 Al-Cu-Li alloy,cold working and artificial aging were carried out to produce 2A97 Al-Cu-Li alloys under different thermomechanical conditions.Quasi-in-situ analysis,traditional immersion test and electrochemical measurement were then conducted to examine the corrosion behavior of 2A97 alloys.It is revealed that precipitate significantly affects Cu enrichment at corrosion fronts,which determines corrosion susceptibility of alloys,whereas grain-stored energy distribution is closely associated with localized corrosion propagation.It is also indicated that quasi-in-situ analysis exhibits a consistent corrosion evolution with traditional immersion tests,which is regarded as a proper method to explore localized corrosion mechanisms by providing local microstructural information with enhanced time and spatial resolutions.展开更多
This paper reviewed two types of network storage technique: NAS and SAN. After comparing and analyzing, it concluded that the ultimate realization of network storage will be in the eventual convergence of NAS and SAN ...This paper reviewed two types of network storage technique: NAS and SAN. After comparing and analyzing, it concluded that the ultimate realization of network storage will be in the eventual convergence of NAS and SAN architectures. Currently, all the integration methods are based on the architecture level. This paper presented a device level integration scheme based on IXP1200 network processor. The device can be used as an NAS file server or an SAN’s storage node. Furthermore, it can be used as a bridge to connect NAS and SAN, and then be shared by their clients.展开更多
The experimental large fluctuation in odd-even differences in moments ofinertia of deformed actinide nuclei is investigated using the particle-number conserving (PNC)method for treating the cranked shell model with mo...The experimental large fluctuation in odd-even differences in moments ofinertia of deformed actinide nuclei is investigated using the particle-number conserving (PNC)method for treating the cranked shell model with monopole and quadrupole pairing interactions. PNCcalculations show that the large odd-even difference in moments of inertia mainly comes from theinterference contributions j(μv) from particles in high j intruder orbitals μ and v quite near theFermi surface, which have no counterpart in the BCS formalism. The effective monopole andquadrupole pairing interaction strengths are determined to fit the experimental odd-even differencesin binding energies and bandhead moments of inertia. The experimental results for the variation ofmoments of inertia with rotational frequency ω are reproduced well by the PNC calculation. Thenearly identical experimental moments of inertia between ~(236)U(gsb) and ~(238)U(gsb) at lowfrequencies hω ≤ 0.20 MeV are also reproduced quite well.展开更多
Investigations were conducted to establish effects of fermentation and drying on the fermentation index (FI) and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design...Investigations were conducted to establish effects of fermentation and drying on the fermentation index (FI) and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design with the principal factors being pod storage (0, 3, 7 and 10 d) and fermentation time (0, 3 and 6 d) to study the changes occurring during the fermentation process. The study also used a 4 x 3 full factorial design with pod storage (0, 3, 7 and 10 d) and drying time (0, 3 and 7 d) being the principal factors investigated to study the changes occurring during the drying process. FI and cut test of the beans were studied during fermentation as well as the drying process. FI of the beans increased significantly with pod storage and fermentation but decreased slightly during drying. FI of the unfermented beans increased slightly from 0.674 for the unstored pods to 0.763 after 10 days of pod storage. The FI of the fermented beans (six days fermentation) also increased from 1.390 for the unstored pods to 1.424 for pods stored for 10 days. It decreased from 1.389 at the start of drying for the unstored pods to 1.105 for pods stored for 10 days at the end of drying (seven days). FI of all the beans were however, above 1.0 at the end of fermentation and drying for all pod storage treatments. Cut test revealed that storage of pods for 3, 7 and 10 days increased the percentage of brown beans by 66%, 94% and 72%, respectively, by the sixth day of fermentation. Percentage of brown beans decreased to 61%, 76% and 63%, respectively, for pods stored for 3, 7 and 10 d at the end of drying (seven days). Cocoa pods can be stored for up to 10 days, fermented for six days and dried for seven days with the necessary formation of brown pigments characteristics of well fermented and dried cocoa beans.展开更多
A rod-like NiCo2O4 modified glassy carbon electrode was fabricated and used for non-enzymatic glucose sensing. The NiCo2O4 was prepared by a facile hydrothermal reaction and subsequently treated in a commercial microw...A rod-like NiCo2O4 modified glassy carbon electrode was fabricated and used for non-enzymatic glucose sensing. The NiCo2O4 was prepared by a facile hydrothermal reaction and subsequently treated in a commercial microwave oven to eliminate the residual water introduced during the hydrothermal procedure. Structural analysis showed that there was no significant structural alteration before and after microwave treatment. The elimination of water residuals was confirmed by the stoichiometric ratio change by using element analysis. The microwave treated NiCo2O4 (M-NiCo2O4) showed excellent performance as a glucose sensor (sensitivity 431.29 μA·mmol/L-1·cm-2). The sensing performance decreases dramatically by soaking the M-NiCo2O4 in water. This result indicates that the introduction of residual water during hydrothermal process strongly affects the electrochemical performance and microwave pre-treatment is crucial for better sensory performance.展开更多
Harvested fruits of mango (Mangifera indica) suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigat...Harvested fruits of mango (Mangifera indica) suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ (hot) or at room temperature and then either stored under ambient conditions (27-29 ℃) or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid (%TA) of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures (11-12 ℃) had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures (11-12 ℃) in order to slow down the rate of ripening and to reduce anthracnose infection.展开更多
Physico-chemical composition of sweet orange (Citrus sinensis L.) cv. blood red was determined in relation to different storage conditions and micronutrients application at department of horticulture, Agricultural U...Physico-chemical composition of sweet orange (Citrus sinensis L.) cv. blood red was determined in relation to different storage conditions and micronutrients application at department of horticulture, Agricultural University Peshawar, Pakistan during 2006-2007 and 2007-2008. The post-harvest quality of sweet orange was evaluated for 60 days storage with 20 days intervals. Fruit were harvested after the foliar application of zinc and boron in two consecutive seasons. The harvested fruits were stored at an ambient temperature (ATS) of 25 + 2 ℃ and at low temperature storage (LTS) of 15 ± 2 ℃ with 60%-70% relative humidity (RH) for 60 days. Sweet oranges stored at LTS maintained better fruit quality than ATS. The foliar application of zinc and boron significantly enhanced fruit juice content, total soluble solids (TSS), ascorbic acid (AA) and non-reducing sugar (NRS) of fruit. However, fruit juice content, TSS and AA were observed significantly higher, when the fruit was treated with high zinc (1%) and low boron (0.02%). The percent of weight loss, disease incidence, TSS and reducing sugar (RS) increased with increasing the storage durations. A reduction was noted in fruit juice, AA and NRS with increasing the storage durations.展开更多
The clustering of trajectories over huge volumes of streaming data has been rec- ognized as critical for many modem applica- tions. In this work, we propose a continuous clustering of trajectories of moving objects ov...The clustering of trajectories over huge volumes of streaming data has been rec- ognized as critical for many modem applica- tions. In this work, we propose a continuous clustering of trajectories of moving objects over high speed data streams, which updates online trajectory clusters on basis of incremental line- segment clustering. The proposed clustering algorithm obtains trajectory clusters efficiently and stores all closed trajectory clusters in a bi- tree index with efficient search capability. Next, we present two query processing methods by utilising three proposed pruning strategies to fast handle two continuous spatio-temporal queries, threshold-based trajectory clustering queries and threshold-based trajectory outlier detections. Finally, the comprehensive experi- mental studies demonstrate that our algorithm achieves excellent effectiveness and high effi- ciency for continuous clustering on both syn- thetic and real streaming data, and the propo- sed query processing methods utilise average 90% less time than the naive query methods.展开更多
Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic pro...Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic processing unit).Aiming at this problem,a fast weighting method for PIC simulation on GPU-accelerated systems was proposed to avoid the atomic memory operations during the weighting process.The method was implemented by taking advantage of GPU's thread synchronization mechanism and dividing the problem space properly.Moreover,software managed shared memory on the GPU was employed to buffer the intermediate data.The experimental results show that the method achieves speedups up to 3.5 times compared to previous works,and runs 20.08 times faster on one NVIDIA Tesla M2090 GPU compared to a single core of Intel Xeon X5670 CPU.展开更多
There is a growing awareness among industry players of reaping the benefits of mobile-cloud convergence by extending today's unmodified cloud to a decentralized two-level cloud-cloudlet architecture based on emerg...There is a growing awareness among industry players of reaping the benefits of mobile-cloud convergence by extending today's unmodified cloud to a decentralized two-level cloud-cloudlet architecture based on emerging mobile-edge computing(MEC) capabilities. In light of future 5G mobile networks moving toward decentralization based on cloudlets, intelligent base stations, and MEC, the inherent distributed processing and storage capabilities of radio-and-fiber(R&F) networks may be exploited for new applications, e.g., cognitive assistance, augmented reality, or cloud robotics. In this paper, we first revisit fiber-wireless(Fi Wi) networks in the context of conventional clouds and emerging cloudlets, thereby highlighting the limitations of conventional radio-overfiber(Ro F) networks such as China Mobile's centralized cloud radio access network(C-RAN) to meet the aforementioned trends. Furthermore, we pay close attention to the specific design challenges of data center networks and revisit our switchless arrayedwaveguide grating(AWG) based network with efficient support of east-west flows and enhanced scalability.展开更多
Virtual memory management is always a very essential issue of the modern microprocessor design. A memory management unit (MMU) is designed to implement a virtual machine for user programs, and provides a management me...Virtual memory management is always a very essential issue of the modern microprocessor design. A memory management unit (MMU) is designed to implement a virtual machine for user programs, and provides a management mechanism between the operating system and user programs. This paper analyzes the tradeoffs considered in the MMU design of Unity 11 CPU of Peking University, and introduces in detail the solution of pure hardware table walking with two level page table organization. The implementation takes care of required operations and high performances needed by modern operating systems and low costs needed by embedded systems. This solution has been silicon proven, and successfully porting the Linux 2.4.17 kernel, the XWindow system, GNOME and most application software onto the Unity platform.展开更多
Different tests were carried out to assess the efficiency of replacing plant protection products used at the main application points in citrus fruit packinghouses with natural treatments. The efficiency of an aqueous ...Different tests were carried out to assess the efficiency of replacing plant protection products used at the main application points in citrus fruit packinghouses with natural treatments. The efficiency of an aqueous treatment containing potassium sorbate was found to significantly reduce decaying in Marisol mandarins previously inoculated with Penicillium digitatum and Penicillium italicum. The same food preservative was used in conjunction with a fruit detergent and was applied on Washington Navel oranges and the reduction in the appearance of decaying was similar to that obtained using Guazatine. Finally, two different essential oils were tested. One was combined with a coating and the KS, whilst the other was applied as a fumigant. In the case of wax treatments, it was found that the combination of essential oil or KS with Imazalil at half the dose (0.1%) was equivalent to treatment with a higher dose of Imazalil (0.2%) thus making it possible to reduce the dose of plant protection products used without reducing decay control effectiveness. The treatment with a fumigant with essential oil has a level of efficiency similar to Imazalil against PI. These treatments can be considered a viable alternative to the use of plant protection products.展开更多
Most image interpolation algorithms currently used suffer visually to some extent the effects of blurred edges and jagged artifacts in the image. This letter presents an adaptive feature preserving bidirectional flow ...Most image interpolation algorithms currently used suffer visually to some extent the effects of blurred edges and jagged artifacts in the image. This letter presents an adaptive feature preserving bidirectional flow process, where an inverse diffusion is performed to enhance edges along the normal directions to the iso-phote lines (edges), while a normal diffusion is done to remove artifacts ('jaggies') along the tangent directions. In order to preserve image features such as edges, angles and textures, the nonlinear diffusion coefficients are locally adjusted according to the first order and the second order directional derivatives of the image. Experimental results on the Lena image demonstrate that our interpolation algorithm substantially improves the subjective quality of the interpolated images over conventional interpolations.展开更多
Helper-thread of a task can hide the memory access time of irregular data on the chip muhi-core processor (CMP). For constructing a compiler that effectively supports the helper-thread of a task in the multi-core sc...Helper-thread of a task can hide the memory access time of irregular data on the chip muhi-core processor (CMP). For constructing a compiler that effectively supports the helper-thread of a task in the multi-core scenario based on the last level shared cache, this paper studies its performance stable condi- tions. Unfortunately, there is no existing model that allows extensive investigation of the impact of stable conditions, we present the base of pre-computation that is formalized by our degraded task-pair 〈 T, T' 〉 with the helper-thread, and its stable conditions are analyzed. Finally, a novel performance model and a constructing method of pre-computation based on our positive degraded task-pair are proposed. The efficient results are shown by our experiments. If we further exploit memory level parallelism (MLP) for our task-pair, the task-pair 〈 T, T' 〉 can reach better performance.展开更多
In this paper, a study related to the expected performance behaviour of present 3-level cache system for multi-core systems is presented. For this a queuing model for present 3-level cache system for multi-core proces...In this paper, a study related to the expected performance behaviour of present 3-level cache system for multi-core systems is presented. For this a queuing model for present 3-level cache system for multi-core processors is developed and its possible performance has been analyzed with the increase in number of cores. Various important performance parameters like access time and utilization of individual cache at different level and overall average access time of the cache system is determined. Results for up to 1024 cores have been reported in this paper.展开更多
In South Africa, the nuclear forensics approach and its functions hosted and managed by Necsa, in support of any nuclear security investigations, start from the incident scene when the nuclear or radioactive material ...In South Africa, the nuclear forensics approach and its functions hosted and managed by Necsa, in support of any nuclear security investigations, start from the incident scene when the nuclear or radioactive material (that is out of regulatory control) is being handled and handed over to Necsa Emergency Control Centre by the South African law enforcement agencies in the presence of NOMS Department official. The main objective of this approach is to increase the credibility status of the chain of custody on the handling of the material during incident (crime) scene management process (for both nuclear forensics and traditional forensic evidence collection) and its transportation from the scene to the suitable storage facility at Necsa. Aspects to be looked into during the response process include interactions between law enforcement agencies, Necsa relevant departments and the National Nuclear Regulator of South Africa. This paper focuses on the entire whole response process and associated prior arrangements, in order to show and provide a set of requirements attached to the material, the scope of critical relevant technical and law enforcement information that to be acquired by all parties involving and participating in the nuclear/radiological incident or event response process before the material is authorized for storage at a suitably qualified Necsa's nuclear forensics, which is dedicated storage facility on Pelindaba site.展开更多
基金supports from the National Natural Science Foundation of China(Nos.52371065,52001128)the Hubei Provincial Natural Science Foundation of China(No.2023AFB637)。
文摘As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stored energy on localized corrosion evolution in 2A97 Al-Cu-Li alloy,cold working and artificial aging were carried out to produce 2A97 Al-Cu-Li alloys under different thermomechanical conditions.Quasi-in-situ analysis,traditional immersion test and electrochemical measurement were then conducted to examine the corrosion behavior of 2A97 alloys.It is revealed that precipitate significantly affects Cu enrichment at corrosion fronts,which determines corrosion susceptibility of alloys,whereas grain-stored energy distribution is closely associated with localized corrosion propagation.It is also indicated that quasi-in-situ analysis exhibits a consistent corrosion evolution with traditional immersion tests,which is regarded as a proper method to explore localized corrosion mechanisms by providing local microstructural information with enhanced time and spatial resolutions.
文摘This paper reviewed two types of network storage technique: NAS and SAN. After comparing and analyzing, it concluded that the ultimate realization of network storage will be in the eventual convergence of NAS and SAN architectures. Currently, all the integration methods are based on the architecture level. This paper presented a device level integration scheme based on IXP1200 network processor. The device can be used as an NAS file server or an SAN’s storage node. Furthermore, it can be used as a bridge to connect NAS and SAN, and then be shared by their clients.
文摘The experimental large fluctuation in odd-even differences in moments ofinertia of deformed actinide nuclei is investigated using the particle-number conserving (PNC)method for treating the cranked shell model with monopole and quadrupole pairing interactions. PNCcalculations show that the large odd-even difference in moments of inertia mainly comes from theinterference contributions j(μv) from particles in high j intruder orbitals μ and v quite near theFermi surface, which have no counterpart in the BCS formalism. The effective monopole andquadrupole pairing interaction strengths are determined to fit the experimental odd-even differencesin binding energies and bandhead moments of inertia. The experimental results for the variation ofmoments of inertia with rotational frequency ω are reproduced well by the PNC calculation. Thenearly identical experimental moments of inertia between ~(236)U(gsb) and ~(238)U(gsb) at lowfrequencies hω ≤ 0.20 MeV are also reproduced quite well.
文摘Investigations were conducted to establish effects of fermentation and drying on the fermentation index (FI) and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design with the principal factors being pod storage (0, 3, 7 and 10 d) and fermentation time (0, 3 and 6 d) to study the changes occurring during the fermentation process. The study also used a 4 x 3 full factorial design with pod storage (0, 3, 7 and 10 d) and drying time (0, 3 and 7 d) being the principal factors investigated to study the changes occurring during the drying process. FI and cut test of the beans were studied during fermentation as well as the drying process. FI of the beans increased significantly with pod storage and fermentation but decreased slightly during drying. FI of the unfermented beans increased slightly from 0.674 for the unstored pods to 0.763 after 10 days of pod storage. The FI of the fermented beans (six days fermentation) also increased from 1.390 for the unstored pods to 1.424 for pods stored for 10 days. It decreased from 1.389 at the start of drying for the unstored pods to 1.105 for pods stored for 10 days at the end of drying (seven days). FI of all the beans were however, above 1.0 at the end of fermentation and drying for all pod storage treatments. Cut test revealed that storage of pods for 3, 7 and 10 days increased the percentage of brown beans by 66%, 94% and 72%, respectively, by the sixth day of fermentation. Percentage of brown beans decreased to 61%, 76% and 63%, respectively, for pods stored for 3, 7 and 10 d at the end of drying (seven days). Cocoa pods can be stored for up to 10 days, fermented for six days and dried for seven days with the necessary formation of brown pigments characteristics of well fermented and dried cocoa beans.
基金supported by the Shandong Provincial Natural Science Foundation,China(No.ZR2017QB015)the National Natural Science Foundation of China(No.21773309)China University of Petroleum Student’s Platform for Innovation and Entrepreneurship Training Program(No.20161449)
文摘A rod-like NiCo2O4 modified glassy carbon electrode was fabricated and used for non-enzymatic glucose sensing. The NiCo2O4 was prepared by a facile hydrothermal reaction and subsequently treated in a commercial microwave oven to eliminate the residual water introduced during the hydrothermal procedure. Structural analysis showed that there was no significant structural alteration before and after microwave treatment. The elimination of water residuals was confirmed by the stoichiometric ratio change by using element analysis. The microwave treated NiCo2O4 (M-NiCo2O4) showed excellent performance as a glucose sensor (sensitivity 431.29 μA·mmol/L-1·cm-2). The sensing performance decreases dramatically by soaking the M-NiCo2O4 in water. This result indicates that the introduction of residual water during hydrothermal process strongly affects the electrochemical performance and microwave pre-treatment is crucial for better sensory performance.
文摘Harvested fruits of mango (Mangifera indica) suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ (hot) or at room temperature and then either stored under ambient conditions (27-29 ℃) or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid (%TA) of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures (11-12 ℃) had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures (11-12 ℃) in order to slow down the rate of ripening and to reduce anthracnose infection.
文摘Physico-chemical composition of sweet orange (Citrus sinensis L.) cv. blood red was determined in relation to different storage conditions and micronutrients application at department of horticulture, Agricultural University Peshawar, Pakistan during 2006-2007 and 2007-2008. The post-harvest quality of sweet orange was evaluated for 60 days storage with 20 days intervals. Fruit were harvested after the foliar application of zinc and boron in two consecutive seasons. The harvested fruits were stored at an ambient temperature (ATS) of 25 + 2 ℃ and at low temperature storage (LTS) of 15 ± 2 ℃ with 60%-70% relative humidity (RH) for 60 days. Sweet oranges stored at LTS maintained better fruit quality than ATS. The foliar application of zinc and boron significantly enhanced fruit juice content, total soluble solids (TSS), ascorbic acid (AA) and non-reducing sugar (NRS) of fruit. However, fruit juice content, TSS and AA were observed significantly higher, when the fruit was treated with high zinc (1%) and low boron (0.02%). The percent of weight loss, disease incidence, TSS and reducing sugar (RS) increased with increasing the storage durations. A reduction was noted in fruit juice, AA and NRS with increasing the storage durations.
基金supported by the National Natural Science Foundation of China under Grants No.61172049,No.61003251the National High Technology Research and Development Program of China(863 Program)under Grant No.2011AA040101the Doctoral Fund of Ministry of Education of Chinaunder Grant No.20100006110015
文摘The clustering of trajectories over huge volumes of streaming data has been rec- ognized as critical for many modem applica- tions. In this work, we propose a continuous clustering of trajectories of moving objects over high speed data streams, which updates online trajectory clusters on basis of incremental line- segment clustering. The proposed clustering algorithm obtains trajectory clusters efficiently and stores all closed trajectory clusters in a bi- tree index with efficient search capability. Next, we present two query processing methods by utilising three proposed pruning strategies to fast handle two continuous spatio-temporal queries, threshold-based trajectory clustering queries and threshold-based trajectory outlier detections. Finally, the comprehensive experi- mental studies demonstrate that our algorithm achieves excellent effectiveness and high effi- ciency for continuous clustering on both syn- thetic and real streaming data, and the propo- sed query processing methods utilise average 90% less time than the naive query methods.
基金Projects(61170049,60903044)supported by National Natural Science Foundation of ChinaProject(2012AA010903)supported by National High Technology Research and Development Program of China
文摘Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic processing unit).Aiming at this problem,a fast weighting method for PIC simulation on GPU-accelerated systems was proposed to avoid the atomic memory operations during the weighting process.The method was implemented by taking advantage of GPU's thread synchronization mechanism and dividing the problem space properly.Moreover,software managed shared memory on the GPU was employed to buffer the intermediate data.The experimental results show that the method achieves speedups up to 3.5 times compared to previous works,and runs 20.08 times faster on one NVIDIA Tesla M2090 GPU compared to a single core of Intel Xeon X5670 CPU.
文摘There is a growing awareness among industry players of reaping the benefits of mobile-cloud convergence by extending today's unmodified cloud to a decentralized two-level cloud-cloudlet architecture based on emerging mobile-edge computing(MEC) capabilities. In light of future 5G mobile networks moving toward decentralization based on cloudlets, intelligent base stations, and MEC, the inherent distributed processing and storage capabilities of radio-and-fiber(R&F) networks may be exploited for new applications, e.g., cognitive assistance, augmented reality, or cloud robotics. In this paper, we first revisit fiber-wireless(Fi Wi) networks in the context of conventional clouds and emerging cloudlets, thereby highlighting the limitations of conventional radio-overfiber(Ro F) networks such as China Mobile's centralized cloud radio access network(C-RAN) to meet the aforementioned trends. Furthermore, we pay close attention to the specific design challenges of data center networks and revisit our switchless arrayedwaveguide grating(AWG) based network with efficient support of east-west flows and enhanced scalability.
文摘Virtual memory management is always a very essential issue of the modern microprocessor design. A memory management unit (MMU) is designed to implement a virtual machine for user programs, and provides a management mechanism between the operating system and user programs. This paper analyzes the tradeoffs considered in the MMU design of Unity 11 CPU of Peking University, and introduces in detail the solution of pure hardware table walking with two level page table organization. The implementation takes care of required operations and high performances needed by modern operating systems and low costs needed by embedded systems. This solution has been silicon proven, and successfully porting the Linux 2.4.17 kernel, the XWindow system, GNOME and most application software onto the Unity platform.
文摘Different tests were carried out to assess the efficiency of replacing plant protection products used at the main application points in citrus fruit packinghouses with natural treatments. The efficiency of an aqueous treatment containing potassium sorbate was found to significantly reduce decaying in Marisol mandarins previously inoculated with Penicillium digitatum and Penicillium italicum. The same food preservative was used in conjunction with a fruit detergent and was applied on Washington Navel oranges and the reduction in the appearance of decaying was similar to that obtained using Guazatine. Finally, two different essential oils were tested. One was combined with a coating and the KS, whilst the other was applied as a fumigant. In the case of wax treatments, it was found that the combination of essential oil or KS with Imazalil at half the dose (0.1%) was equivalent to treatment with a higher dose of Imazalil (0.2%) thus making it possible to reduce the dose of plant protection products used without reducing decay control effectiveness. The treatment with a fumigant with essential oil has a level of efficiency similar to Imazalil against PI. These treatments can be considered a viable alternative to the use of plant protection products.
基金Supported by the National Natural Science Foundation of China(No.60472033)the Key Laboratory Project of Information Science & Engineering of Railway of National Ministry of Railways, China (No.tdxx0510)the Technological Innovation Fund of Excellent Doctorial Candidate of Beijing Jiaotong University,China(No.48007)
文摘Most image interpolation algorithms currently used suffer visually to some extent the effects of blurred edges and jagged artifacts in the image. This letter presents an adaptive feature preserving bidirectional flow process, where an inverse diffusion is performed to enhance edges along the normal directions to the iso-phote lines (edges), while a normal diffusion is done to remove artifacts ('jaggies') along the tangent directions. In order to preserve image features such as edges, angles and textures, the nonlinear diffusion coefficients are locally adjusted according to the first order and the second order directional derivatives of the image. Experimental results on the Lena image demonstrate that our interpolation algorithm substantially improves the subjective quality of the interpolated images over conventional interpolations.
文摘Helper-thread of a task can hide the memory access time of irregular data on the chip muhi-core processor (CMP). For constructing a compiler that effectively supports the helper-thread of a task in the multi-core scenario based on the last level shared cache, this paper studies its performance stable condi- tions. Unfortunately, there is no existing model that allows extensive investigation of the impact of stable conditions, we present the base of pre-computation that is formalized by our degraded task-pair 〈 T, T' 〉 with the helper-thread, and its stable conditions are analyzed. Finally, a novel performance model and a constructing method of pre-computation based on our positive degraded task-pair are proposed. The efficient results are shown by our experiments. If we further exploit memory level parallelism (MLP) for our task-pair, the task-pair 〈 T, T' 〉 can reach better performance.
文摘In this paper, a study related to the expected performance behaviour of present 3-level cache system for multi-core systems is presented. For this a queuing model for present 3-level cache system for multi-core processors is developed and its possible performance has been analyzed with the increase in number of cores. Various important performance parameters like access time and utilization of individual cache at different level and overall average access time of the cache system is determined. Results for up to 1024 cores have been reported in this paper.
文摘In South Africa, the nuclear forensics approach and its functions hosted and managed by Necsa, in support of any nuclear security investigations, start from the incident scene when the nuclear or radioactive material (that is out of regulatory control) is being handled and handed over to Necsa Emergency Control Centre by the South African law enforcement agencies in the presence of NOMS Department official. The main objective of this approach is to increase the credibility status of the chain of custody on the handling of the material during incident (crime) scene management process (for both nuclear forensics and traditional forensic evidence collection) and its transportation from the scene to the suitable storage facility at Necsa. Aspects to be looked into during the response process include interactions between law enforcement agencies, Necsa relevant departments and the National Nuclear Regulator of South Africa. This paper focuses on the entire whole response process and associated prior arrangements, in order to show and provide a set of requirements attached to the material, the scope of critical relevant technical and law enforcement information that to be acquired by all parties involving and participating in the nuclear/radiological incident or event response process before the material is authorized for storage at a suitably qualified Necsa's nuclear forensics, which is dedicated storage facility on Pelindaba site.