The Poisson point process(PPP) has been widely used in wireless network modeling and performance analysis due to the independence between its nodes. Therefore, it may not be a suitable model for many of the exclusive ...The Poisson point process(PPP) has been widely used in wireless network modeling and performance analysis due to the independence between its nodes. Therefore, it may not be a suitable model for many of the exclusive networks between the nodes. This paper analyzes the energy efficiency(EE) and optimizes the two-tier heterogeneous cellular networks(Het Nets). Considering the mutual exclusion between macro base stations(MBSs) distribution, the deployment of MBSs is modeled by the Matérn hard-core point process(MHCPP), and the deployment of pico base stations(PBSs) is modeled by the PPP. We adopt a simple approximation method to study the signal to interference ratio(SIR) distribution in two-tier MHCPP-PPP networks and then derive the coverage probabilities, the average data rates and the energy efficiency of Het Nets. Finally, an optimization algorithm is proposed to improve the EE of Het Nets by controlling the transmit power of PBSs. The simulation results show that the EE of a system can be effectively improved by selecting the appropriate transmit power for the PBSs. In addition, two-tier MHCPP-PPP Het Nets have higher energy efficiency than two-tier PPP-PPP Het Nets.展开更多
Sensing coverage is a fundamental design issue in wireless sensor networks(WSNs),while sensor scheduling ensures coverage degree to the monitored event and extends the network lifetime.In this paper,we address k-cover...Sensing coverage is a fundamental design issue in wireless sensor networks(WSNs),while sensor scheduling ensures coverage degree to the monitored event and extends the network lifetime.In this paper,we address k-coverage scheduling problem in dense WSNs,we maintain a connected k-coverage energy efficiently through a novel Hard-Core based Coordinated Scheduling(HCCS),in which hardcore is a thinning process in stochastic geometry that inhibits more than one active sensor covering any area redundantly in a minimum distance. As compared with existing coordinated scheduling,HCCS allows coordination between sensors with little communication overhead.Moreover,due to the traditional sensing models in k-coverage analysis is unsuitable to describe the characteristic of transmit channel in dense WSNs,we propose a novel sensing model integrating Rayleigh Fading and Distribution of Active sensors(RFDA),and derive the coverage measure and k-coverage probability for the monitored event under RFDA. In addition,we analyze the influence factors,i.e. the transmit condition and monitoring degree to the k-coverage probability. Finally,through Monte Carlo simulations,it is shown that the k-coverage probability of HCCS outperforms that of its random scheduling counterpart.展开更多
We investigate the energy spectrum of ground state and quasi-particle excitation spectrum of hard-core bosons, which behave very much like spinless noninteracting ferrnions, in optical lattices by means of the perturb...We investigate the energy spectrum of ground state and quasi-particle excitation spectrum of hard-core bosons, which behave very much like spinless noninteracting ferrnions, in optical lattices by means of the perturbation expansion and Bogoliubov approach. The results show that the energy spectrum has a single band structure, and the energy is lower near zero momentum; the excitation spectrum gives corresponding energy gap, and the system is in Mort-insulating state at Tonks limit. The analytic result of energy spectrum is in good agreement with that calculated in terms of Green＇s function at strong correlation limit.展开更多
In this work,we theoretically study hard-core bosons on a two-dimensional square optical superlattice at T = 0.First of all,we present the mean field phase diagram of this model in terms of the chemical potential μ a...In this work,we theoretically study hard-core bosons on a two-dimensional square optical superlattice at T = 0.First of all,we present the mean field phase diagram of this model in terms of the chemical potential μ and the alternating potential strength △.Besides a superfluid(SF) phase at △ = 0 and a charge density wave(CDW)phase in the large △ at half filling,we demonstrate that a supersolid(SS) phase emerges in the moderate △.Then,we focus on the μ = 0,e.g.,half filling case,using large-S semi-classical spin-wave approximation to study the SS to CDW quantum phase transition.In particular,we calculate the ground-state energy and the superfluid density at the level of1/S correction.We then compare the spin-wave results with the large scale quantum Monte Carlo(QMC) simulations using the cluster stochastic series expansion(CSSE) algorithm,and find that while the spin wave method is intuitive with clear physical pictures,the quantum critical point is quite different from that of numerical results which is believed to be accurate.We suggest that as simple as it is,this model still exhibits strong quantum fluctuations near the quantum critical point beyond the power of semiclassical spin-wave approach.展开更多
A team of researchers from the University of Science and Technology of China(USTC)of the Chinese Academy of Sciences(CAS)and its partners have made significant advancements in random quantum circuit sampling with Zuch...A team of researchers from the University of Science and Technology of China(USTC)of the Chinese Academy of Sciences(CAS)and its partners have made significant advancements in random quantum circuit sampling with Zuchongzhi-3,a superconducting quantum computing prototype featuring 105 qubits and 182 couplers.展开更多
目前,多核实时系统中同步任务的节能调度研究主要针对的是同构多核处理器平台,而异构多核处理器架构能够更有效地发挥系统性能。将现有的研究直接应用于异构多核系统,在保证可调度性的情况下会导致能耗变高。对此,通过使用动态电压与频...目前,多核实时系统中同步任务的节能调度研究主要针对的是同构多核处理器平台,而异构多核处理器架构能够更有效地发挥系统性能。将现有的研究直接应用于异构多核系统,在保证可调度性的情况下会导致能耗变高。对此,通过使用动态电压与频率调节(Dynamic Voltage Frequency Scaling,DVFS)技术,研究异构多核实时系统中基于任务同步的节能调度问题,提出同步感知的最大能耗节省优先算法(Synchronization Aware-Largest Energy Saved First,SA-LESF)。该算法针对所有任务的速度配置进行迭代优化,直至所有任务均达到其最大限度节能的速度配置。此外,进一步提出基于动态松弛时间回收的同步感知最大能耗节省优先算法(Synchronization Aware-Largest Energy Saved First with Dynamic Reclamation,SA-LESF-DR)。该算法在保证实时任务可调度的同时,实施相应的回收策略,进一步降低系统能耗。实验结果表明,SA-LESF与SA-LESF-DR算法在能耗表现上具有优势,在相同任务集下,相比其他算法可节省高达30%的能耗。展开更多
This paper presents a smart compensation system based on MCA7707 (a kind of signal processor). The li near errors and high order errors of a sensor (especially piezoresistive sensor) can be corrected by using this s...This paper presents a smart compensation system based on MCA7707 (a kind of signal processor). The li near errors and high order errors of a sensor (especially piezoresistive sensor) can be corrected by using this system. It can optimize the process of piezoresi stive sensor calibration and compensation, then, a total error factor within 0.2 % of the sensor′s repeatability errors is obtained. Data are recorded and coeff icients are determined automatically by this system, thus, the sensor compensati on is simplified greatly. For operating easily, a wizard compensation program is designed to correct every error and to get the optimum compensation.展开更多
As an important branch of information security algorithms,the efficient and flexible implementation of stream ciphers is vital.Existing implementation methods,such as FPGA,GPP and ASIC,provide a good support,but they ...As an important branch of information security algorithms,the efficient and flexible implementation of stream ciphers is vital.Existing implementation methods,such as FPGA,GPP and ASIC,provide a good support,but they could not achieve a better tradeoff between high speed processing and high flexibility.ASIC has fast processing speed,but its flexibility is poor,GPP has high flexibility,but the processing speed is slow,FPGA has high flexibility and processing speed,but the resource utilization is very low.This paper studies a stream cryptographic processor which can efficiently and flexibly implement a variety of stream cipher algorithms.By analyzing the structure model,processing characteristics and storage characteristics of stream ciphers,a reconfigurable stream cryptographic processor with special instructions based on VLIW is presented,which has separate/cluster storage structure and is oriented to stream cipher operations.The proposed instruction structure can effectively support stream cipher processing with multiple data bit widths,parallelism among stream cipher processing with different data bit widths,and parallelism among branch control and stream cipher processing with high instruction level parallelism;the designed separate/clustered special bit registers and general register heaps,key register heaps can satisfy cryptographic requirements.So the proposed processor not only flexibly accomplishes the combination of multiple basic stream cipher operations to finish stream cipher algorithms.It has been implemented with 0.18μm CMOS technology,the test results show that the frequency can reach 200 MHz,and power consumption is 310 mw.Ten kinds of stream ciphers were realized in the processor.The key stream generation throughput of Grain-80,W7,MICKEY,ACHTERBAHN and Shrink algorithm is 100 Mbps,66.67 Mbps,66.67 Mbps,50 Mbps and 800 Mbps,respectively.The test result shows that the processor presented can achieve good tradeoff between high performance and flexibility of stream ciphers.展开更多
Objective:To review developments in sound processors over the past 30 years that have resulted in significant improvements in outcomes for Nucleus~ recipients.
A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated o...A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated on the mole fraction of products,methanol conversion,hydrogen yield and the amount of carbon monoxide under various operating conditions.Subsequently,0.5 wt% Ru/Al2O3 as methanation catalyst was prepared by impregnation method and coupled with MSR step to evaluate the capability of methanol processor for CO reduction.Based on the experimental results,the optimum conditions were obtained as feed flow rate of 5mL/h and temperature of 250℃,leading to a low CO selectivity and high H2 yield.The designed reformer with catalyst coated layer was compared with the conventional packed bed reformer at the same operating conditions.The constructed fuel processor had a good performance and excellent capability for on-board hydrogen production.展开更多
Due to the fact that the register files seriously affect the performance and area of coarse-grained reconfigurable cryptographic processors, an efficient structure of the distributed cross-domain register file is prop...Due to the fact that the register files seriously affect the performance and area of coarse-grained reconfigurable cryptographic processors, an efficient structure of the distributed cross-domain register file is proposed to realize a cryptographic processor with a high performance and a lowarea cost. In order to meet the demands of high performance and high flexibility at a lowarea cost, a union structure with the multi-ports access structure, i, e., a distributed crossdomain register file, is designed by analyzing the algorithm features of different ciphers. Considering different algorithm requirements of the global register files and local register files,the circuit design is realized by adopting different design parameters under TSMC( Taiwan Semiconductor Manufacturing Company) 40 nm CMOS( complementary metal oxide semiconductor) technology and compared with other similar works. The experimental results showthat the proposed distributed cross-domain register structure can effectively improve the performance of the unit area, of which the total performance of block per cycle is improved by17. 79% and performance of block per cycle per area is improved by 117%.展开更多
基金partly supported by the National Natural Science Foundation of China(Grant No.61871241,No.61701221)the Natural Science Foundation of Jiangsu Province(No.BK20160781)+1 种基金Nantong Science and Technology Project(No.JC2018127,No.JC2019117)the Research Innovation Project for College Graduates of Jiangsu Province(No.KYLX16_0662)。
文摘The Poisson point process(PPP) has been widely used in wireless network modeling and performance analysis due to the independence between its nodes. Therefore, it may not be a suitable model for many of the exclusive networks between the nodes. This paper analyzes the energy efficiency(EE) and optimizes the two-tier heterogeneous cellular networks(Het Nets). Considering the mutual exclusion between macro base stations(MBSs) distribution, the deployment of MBSs is modeled by the Matérn hard-core point process(MHCPP), and the deployment of pico base stations(PBSs) is modeled by the PPP. We adopt a simple approximation method to study the signal to interference ratio(SIR) distribution in two-tier MHCPP-PPP networks and then derive the coverage probabilities, the average data rates and the energy efficiency of Het Nets. Finally, an optimization algorithm is proposed to improve the EE of Het Nets by controlling the transmit power of PBSs. The simulation results show that the EE of a system can be effectively improved by selecting the appropriate transmit power for the PBSs. In addition, two-tier MHCPP-PPP Het Nets have higher energy efficiency than two-tier PPP-PPP Het Nets.
基金supported by the National Science Foundation of China under Grant 61271186
文摘Sensing coverage is a fundamental design issue in wireless sensor networks(WSNs),while sensor scheduling ensures coverage degree to the monitored event and extends the network lifetime.In this paper,we address k-coverage scheduling problem in dense WSNs,we maintain a connected k-coverage energy efficiently through a novel Hard-Core based Coordinated Scheduling(HCCS),in which hardcore is a thinning process in stochastic geometry that inhibits more than one active sensor covering any area redundantly in a minimum distance. As compared with existing coordinated scheduling,HCCS allows coordination between sensors with little communication overhead.Moreover,due to the traditional sensing models in k-coverage analysis is unsuitable to describe the characteristic of transmit channel in dense WSNs,we propose a novel sensing model integrating Rayleigh Fading and Distribution of Active sensors(RFDA),and derive the coverage measure and k-coverage probability for the monitored event under RFDA. In addition,we analyze the influence factors,i.e. the transmit condition and monitoring degree to the k-coverage probability. Finally,through Monte Carlo simulations,it is shown that the k-coverage probability of HCCS outperforms that of its random scheduling counterpart.
文摘We investigate the energy spectrum of ground state and quasi-particle excitation spectrum of hard-core bosons, which behave very much like spinless noninteracting ferrnions, in optical lattices by means of the perturbation expansion and Bogoliubov approach. The results show that the energy spectrum has a single band structure, and the energy is lower near zero momentum; the excitation spectrum gives corresponding energy gap, and the system is in Mort-insulating state at Tonks limit. The analytic result of energy spectrum is in good agreement with that calculated in terms of Green＇s function at strong correlation limit.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10904096,10604024,11474025the Natural Science Foundation of Beijing under Grant No.1092009
文摘In this work,we theoretically study hard-core bosons on a two-dimensional square optical superlattice at T = 0.First of all,we present the mean field phase diagram of this model in terms of the chemical potential μ and the alternating potential strength △.Besides a superfluid(SF) phase at △ = 0 and a charge density wave(CDW)phase in the large △ at half filling,we demonstrate that a supersolid(SS) phase emerges in the moderate △.Then,we focus on the μ = 0,e.g.,half filling case,using large-S semi-classical spin-wave approximation to study the SS to CDW quantum phase transition.In particular,we calculate the ground-state energy and the superfluid density at the level of1/S correction.We then compare the spin-wave results with the large scale quantum Monte Carlo(QMC) simulations using the cluster stochastic series expansion(CSSE) algorithm,and find that while the spin wave method is intuitive with clear physical pictures,the quantum critical point is quite different from that of numerical results which is believed to be accurate.We suggest that as simple as it is,this model still exhibits strong quantum fluctuations near the quantum critical point beyond the power of semiclassical spin-wave approach.
文摘A team of researchers from the University of Science and Technology of China(USTC)of the Chinese Academy of Sciences(CAS)and its partners have made significant advancements in random quantum circuit sampling with Zuchongzhi-3,a superconducting quantum computing prototype featuring 105 qubits and 182 couplers.
文摘目前,多核实时系统中同步任务的节能调度研究主要针对的是同构多核处理器平台,而异构多核处理器架构能够更有效地发挥系统性能。将现有的研究直接应用于异构多核系统,在保证可调度性的情况下会导致能耗变高。对此,通过使用动态电压与频率调节(Dynamic Voltage Frequency Scaling,DVFS)技术,研究异构多核实时系统中基于任务同步的节能调度问题,提出同步感知的最大能耗节省优先算法(Synchronization Aware-Largest Energy Saved First,SA-LESF)。该算法针对所有任务的速度配置进行迭代优化,直至所有任务均达到其最大限度节能的速度配置。此外,进一步提出基于动态松弛时间回收的同步感知最大能耗节省优先算法(Synchronization Aware-Largest Energy Saved First with Dynamic Reclamation,SA-LESF-DR)。该算法在保证实时任务可调度的同时,实施相应的回收策略,进一步降低系统能耗。实验结果表明,SA-LESF与SA-LESF-DR算法在能耗表现上具有优势,在相同任务集下,相比其他算法可节省高达30%的能耗。
文摘This paper presents a smart compensation system based on MCA7707 (a kind of signal processor). The li near errors and high order errors of a sensor (especially piezoresistive sensor) can be corrected by using this system. It can optimize the process of piezoresi stive sensor calibration and compensation, then, a total error factor within 0.2 % of the sensor′s repeatability errors is obtained. Data are recorded and coeff icients are determined automatically by this system, thus, the sensor compensati on is simplified greatly. For operating easily, a wizard compensation program is designed to correct every error and to get the optimum compensation.
基金supported by National Natural Science Foundation of China with granted No.61404175
文摘As an important branch of information security algorithms,the efficient and flexible implementation of stream ciphers is vital.Existing implementation methods,such as FPGA,GPP and ASIC,provide a good support,but they could not achieve a better tradeoff between high speed processing and high flexibility.ASIC has fast processing speed,but its flexibility is poor,GPP has high flexibility,but the processing speed is slow,FPGA has high flexibility and processing speed,but the resource utilization is very low.This paper studies a stream cryptographic processor which can efficiently and flexibly implement a variety of stream cipher algorithms.By analyzing the structure model,processing characteristics and storage characteristics of stream ciphers,a reconfigurable stream cryptographic processor with special instructions based on VLIW is presented,which has separate/cluster storage structure and is oriented to stream cipher operations.The proposed instruction structure can effectively support stream cipher processing with multiple data bit widths,parallelism among stream cipher processing with different data bit widths,and parallelism among branch control and stream cipher processing with high instruction level parallelism;the designed separate/clustered special bit registers and general register heaps,key register heaps can satisfy cryptographic requirements.So the proposed processor not only flexibly accomplishes the combination of multiple basic stream cipher operations to finish stream cipher algorithms.It has been implemented with 0.18μm CMOS technology,the test results show that the frequency can reach 200 MHz,and power consumption is 310 mw.Ten kinds of stream ciphers were realized in the processor.The key stream generation throughput of Grain-80,W7,MICKEY,ACHTERBAHN and Shrink algorithm is 100 Mbps,66.67 Mbps,66.67 Mbps,50 Mbps and 800 Mbps,respectively.The test result shows that the processor presented can achieve good tradeoff between high performance and flexibility of stream ciphers.
基金funded by Cochlear Limited,the manufacturer of Nucleus implant systems
文摘Objective:To review developments in sound processors over the past 30 years that have resulted in significant improvements in outcomes for Nucleus~ recipients.
基金supported by the Iran National Science Foundation (INSF)
文摘A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated on the mole fraction of products,methanol conversion,hydrogen yield and the amount of carbon monoxide under various operating conditions.Subsequently,0.5 wt% Ru/Al2O3 as methanation catalyst was prepared by impregnation method and coupled with MSR step to evaluate the capability of methanol processor for CO reduction.Based on the experimental results,the optimum conditions were obtained as feed flow rate of 5mL/h and temperature of 250℃,leading to a low CO selectivity and high H2 yield.The designed reformer with catalyst coated layer was compared with the conventional packed bed reformer at the same operating conditions.The constructed fuel processor had a good performance and excellent capability for on-board hydrogen production.
基金The National Natural Science Foundation of China(No.61176024)
文摘Due to the fact that the register files seriously affect the performance and area of coarse-grained reconfigurable cryptographic processors, an efficient structure of the distributed cross-domain register file is proposed to realize a cryptographic processor with a high performance and a lowarea cost. In order to meet the demands of high performance and high flexibility at a lowarea cost, a union structure with the multi-ports access structure, i, e., a distributed crossdomain register file, is designed by analyzing the algorithm features of different ciphers. Considering different algorithm requirements of the global register files and local register files,the circuit design is realized by adopting different design parameters under TSMC( Taiwan Semiconductor Manufacturing Company) 40 nm CMOS( complementary metal oxide semiconductor) technology and compared with other similar works. The experimental results showthat the proposed distributed cross-domain register structure can effectively improve the performance of the unit area, of which the total performance of block per cycle is improved by17. 79% and performance of block per cycle per area is improved by 117%.
