Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and flexibility.However,beam hopping causes the traditional continuous...Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and flexibility.However,beam hopping causes the traditional continuous time-division multiplexing signal in the forward downlink to become a burst signal,satellite terminal receivers need to solve multiple key issues such as burst signal rapid synchronization and high-per-formance reception.Firstly,this paper analyzes the key issues of burst communication for traffic signals in beam hopping sys-tems,and then compares and studies typical carrier synchro-nization algorithms for burst signals.Secondly,combining the requirements of beam-hopping communication systems for effi-cient burst and low signal-to-noise ratio reception of downlink signals in forward links,a decoding assisted bidirectional vari-able parameter iterative carrier synchronization technique is pro-posed,which introduces the idea of iterative processing into car-rier synchronization.Aiming at the technical characteristics of communication signal carrier synchronization,a new technical approach of bidirectional variable parameter iteration is adopted,breaking through the traditional understanding that loop struc-tures cannot adapt to low signal-to-noise ratio burst demodula-tion.Finally,combining the DVB-S2X standard physical layer frame format used in high throughput satellite communication systems,the research and performance simulation are con-ducted.The results show that the new technology proposed in this paper can significantly shorten the carrier synchronization time of burst signals,achieve fast synchronization of low signal-to-noise ratio burst signals,and have the unique advantage of flexible and adjustable parameters.展开更多
This paper describes the model speed and model In/Out （I/O） efficiency of the high-resolution atmospheric general circulation model FAMIL （Finite- volume Atmospheric Model of IAP/LASG） at the National Supercompute...This paper describes the model speed and model In/Out （I/O） efficiency of the high-resolution atmospheric general circulation model FAMIL （Finite- volume Atmospheric Model of IAP/LASG） at the National Supercomputer Center in Tianjin, China, on its Tianhe-lA supercomputer platform. A series of three- model-day simulations were carried out with standard Aqua Planet Experiment （APE） designed within FAMIL to obtain the time stamp for the calculation of model speed, simulation cost, and model 1/O efficiency. The results of the simulation demonstrate that FAMIL has remarkable scalability below 3456 and 6144 cores, and the lowest simulation costs are 1536 and 3456 cores for 12.5 km and 6.25 krn resolutions, respectively. Furthermore, FAMIL has excellent I/O scalability and an efficiency of more than 80% on 6 I/Os and more than 99% on 1536 I/Os.展开更多
Hyperspectral data fusion technique is the key to hyperspectral data processing in recent years. Many fusion methods have been proposed, but little research has been done to evaluate the performances of different data...Hyperspectral data fusion technique is the key to hyperspectral data processing in recent years. Many fusion methods have been proposed, but little research has been done to evaluate the performances of different data fusion methods. In order to meet the urgent need, quantitative correlation analysis(QCA) is proposed to analyse and compare the performances of different fusion methods directly from data before and after fusion. Experiment results show that the new method is effective and the results of comparison are in agreement with the results of application.展开更多
This paper studies several performance metrics of a wireless-powered decode-and-forward(DF) relay network with imperfect channel state information(CSI). In particular, based on the time switching(TS) protocol, the ene...This paper studies several performance metrics of a wireless-powered decode-and-forward(DF) relay network with imperfect channel state information(CSI). In particular, based on the time switching(TS) protocol, the energy-constrained relay harvesting energy from a power beacon(PB), and uses that harvested energy to forward the source information to destination. The closedform expression of the outage probability is firstly derived over Rayleigh fading channels. Then, the asymptotic analysis, throughput as well as the symbol error probability(SEP) are derived based on the expression of the outage probability. Next, both transmission power of the source and the power beacon are optimized through the throughput optimization. Finally, simulations are conducted to corroborate our theoretical analysis, and to reveal the impact of the transmission power of the source and PB as well as the imperfect CSI on the system performance.展开更多
The black soldier fly(BSF),Hermetia illucens(Diptera:Stratiomyidae),is an insect commonly used for the bioconversion of various organic wastes.Not only can the BSF convert organic waste into macromolecular organic sub...The black soldier fly(BSF),Hermetia illucens(Diptera:Stratiomyidae),is an insect commonly used for the bioconversion of various organic wastes.Not only can the BSF convert organic waste into macromolecular organic substances,such as insect pro-teins,but it can also lessen the pollution associated with these waste products by reducing ammonia emissions,for example.In this study,we measured the effects of adding fruit fermentation broth(Fer)and commercial lactic acid bacteria fermentation broth(Em)to kitchen waste(KW),as deodorizing auxiliary substances,on the growth performance of black soldier fly larvae(BSFL),the intestinal flora structure of BSFL,the ammonia emis-sion from the KW substrate,and the microbial community structure of the KW substrate.We found that the addition of Fer or Em increased the body weight of BSFL after 6 d of culture,increasing the growth rate by 9.96%and 7.96%,respectively.The addition of Fer not only reduced the pH of the KW substrate but also increased the relative abundance of probiotics,such as Lactobacillus,Lysinibacillus,and Vagococcus,which inhibited the growth of ammonifiers such as Bacillus,Oligella,Paenalcaligenes,Paenibacillus,Pseu-dogracilibacillus,and Pseudomonas,resulting in the reduction of ammonia emission in the KW substrate.Moreover,the addition of Fer or Em significantly increased the rela-tive abundances of Bacteroides,Campylobacter,Dysgonomonas,Enterococcus,and Ig-natzschineria in the gut of BSFL and increased the species diversity and richness in the K W substrate.Our findings provide a novel way to improve the conversion rate of organic waste and reduce the environmental pollution caused by BSF.展开更多
With the advent of Internet services, big data and cloud computing, high-throughput computing has generated much research interest, especially on high-throughput cloud servers. However, three basic questions are still...With the advent of Internet services, big data and cloud computing, high-throughput computing has generated much research interest, especially on high-throughput cloud servers. However, three basic questions are still not satis-factorily answered： （1） What are the basic metrics （what throughput and high-throughput of what）？ （2） What are the main factors most beneficial to increasing throughput？ （3） Are there any fundamental constraints and how high can the throughput go？ This article addresses these issues by uti- lizing the fifty-year progress in Little＇s law, to reveal three fundamental relations among the seven basic quantities of throughput （2）, number of active threads （L）, waiting time （W）, system power （P）, thread energy （E）, Watts per thread to, threads per Joule 0. In addition to Little＇s law L = λW, we obtain P =λE and λ = Lto0, under reasonable assumptions. These equations help give a first order estimation of per- formance and power consumption targets for billion-thread cloud servers.展开更多
Given the ability of building information models （BIM） to serve as a multidisciplinary data repository, this study attempts to explore and exploit the sustainability value of BIM in delivering buildings that require...Given the ability of building information models （BIM） to serve as a multidisciplinary data repository, this study attempts to explore and exploit the sustainability value of BIM in delivering buildings that require less energy for operations, emit tess carbon dioxide, and provide conducive living environments for occupants. This objective was attained by a critical and extensive literature review that covers the following： （1） building energy consumption, （2） building energy performance and analysis, and （3） BIM and energy assessment. Literature cited in this paper shows that linking an energy analysis toot with a BIM model has helped project design teams to predict and create optimized energy consumption by conducting building energy performance analysis utilizing key performance indicators on average thermal transmitters, resulting heat demand, lighting power, solar heat gains, and ventilation heat losses. An in-depth analysis was conducted on a completed BIM integrated construction project utilizing the Arboleda Project in the Dominican Republic to validate the aforementioned findings. Results show that the BIM-based energy analysis helped the design team attain the world＇s first positive energy building. This study concludes that linking an energy analysis tool with a BIM model helps to expedite the energy analysis process, provide more detailed and accurate results, and deliver energy-efficient buildings. This study further recommends that the adoption of level 2 BIM and BIM integration in energy optimization analysis must be demanded by building regulatory agencies for all projects regardless of procurement method （i.e., government funded or otherwise） or size.展开更多
Compared with single rotor small axial flow fans, dual-rotor small axial flow fans is better regarding the static characteristics. But the aerodynamic noise of dual-rotor small axial flow fans is worse than that of si...Compared with single rotor small axial flow fans, dual-rotor small axial flow fans is better regarding the static characteristics. But the aerodynamic noise of dual-rotor small axial flow fans is worse than that of single rotor small axial flow fans. In order to improve aerodynamic noise of dual-rotor small axial flow fans, the pre-stage blades with different perforation numbers are designed in this research. The RANS equations and the standard k-e turbulence model as well as the FW-H noise model are used to simulate the flow field within the fan. Then, the aerodynamic performance of the fans with different perforation number is compared and analyzed. The results show that： （1） Compared to the prototype fan, the noise of fans with perforation blades is reduced. Additionally, the noise of the fans decreases with the increase of the number of perforations. （2） The vorticity value in the trailing edge of the pre-stage blades of perforated fans is reduced. It is found that the vorticity value in the trailing edge of the pre-stage blades decreases with the increase of the number of perforations. （3） Compared to the prototype fan, the total pressure rising and efficiency of the fans with perforation blades drop slightly.展开更多
基金This work was supported by the Key Research and Development Program of Shaanxi(2022ZDLGY05-08)the Application Innovation Program of CASC(China Aerospace Science and Technology Corporation)(6230107001)+2 种基金the Research Project on Civil Aerospace Technology(D040304)the Research Project of CAST(Y23-WYHXJS-07)the Research Foundation of the Key Laboratory of Spaceborne Information Intelligent Interpretation(2022-ZZKY-JJ-20-01).
文摘Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and flexibility.However,beam hopping causes the traditional continuous time-division multiplexing signal in the forward downlink to become a burst signal,satellite terminal receivers need to solve multiple key issues such as burst signal rapid synchronization and high-per-formance reception.Firstly,this paper analyzes the key issues of burst communication for traffic signals in beam hopping sys-tems,and then compares and studies typical carrier synchro-nization algorithms for burst signals.Secondly,combining the requirements of beam-hopping communication systems for effi-cient burst and low signal-to-noise ratio reception of downlink signals in forward links,a decoding assisted bidirectional vari-able parameter iterative carrier synchronization technique is pro-posed,which introduces the idea of iterative processing into car-rier synchronization.Aiming at the technical characteristics of communication signal carrier synchronization,a new technical approach of bidirectional variable parameter iteration is adopted,breaking through the traditional understanding that loop struc-tures cannot adapt to low signal-to-noise ratio burst demodula-tion.Finally,combining the DVB-S2X standard physical layer frame format used in high throughput satellite communication systems,the research and performance simulation are con-ducted.The results show that the new technology proposed in this paper can significantly shorten the carrier synchronization time of burst signals,achieve fast synchronization of low signal-to-noise ratio burst signals,and have the unique advantage of flexible and adjustable parameters.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05110303)the National Basic Research Program of China (973Program, Grant Nos. 2012CB417203 and 2010CB950404)+1 种基金the National High Technology Research and Development Program of China (863 Program, Grant No. 2010AA012305)the National Natural Science Foundation of China (Grant No. 41023002)
文摘This paper describes the model speed and model In/Out （I/O） efficiency of the high-resolution atmospheric general circulation model FAMIL （Finite- volume Atmospheric Model of IAP/LASG） at the National Supercomputer Center in Tianjin, China, on its Tianhe-lA supercomputer platform. A series of three- model-day simulations were carried out with standard Aqua Planet Experiment （APE） designed within FAMIL to obtain the time stamp for the calculation of model speed, simulation cost, and model 1/O efficiency. The results of the simulation demonstrate that FAMIL has remarkable scalability below 3456 and 6144 cores, and the lowest simulation costs are 1536 and 3456 cores for 12.5 km and 6.25 krn resolutions, respectively. Furthermore, FAMIL has excellent I/O scalability and an efficiency of more than 80% on 6 I/Os and more than 99% on 1536 I/Os.
文摘Hyperspectral data fusion technique is the key to hyperspectral data processing in recent years. Many fusion methods have been proposed, but little research has been done to evaluate the performances of different data fusion methods. In order to meet the urgent need, quantitative correlation analysis(QCA) is proposed to analyse and compare the performances of different fusion methods directly from data before and after fusion. Experiment results show that the new method is effective and the results of comparison are in agreement with the results of application.
基金support by the National Natural Science Foundation of China (nos. 61571340, 61301170)the Fundamental Research Funds for the Central Universities of China under Grant JB150109the 111 Project under Grant B08038
文摘This paper studies several performance metrics of a wireless-powered decode-and-forward(DF) relay network with imperfect channel state information(CSI). In particular, based on the time switching(TS) protocol, the energy-constrained relay harvesting energy from a power beacon(PB), and uses that harvested energy to forward the source information to destination. The closedform expression of the outage probability is firstly derived over Rayleigh fading channels. Then, the asymptotic analysis, throughput as well as the symbol error probability(SEP) are derived based on the expression of the outage probability. Next, both transmission power of the source and the power beacon are optimized through the throughput optimization. Finally, simulations are conducted to corroborate our theoretical analysis, and to reveal the impact of the transmission power of the source and PB as well as the imperfect CSI on the system performance.
基金funded by the Provincial Major Scientific and Technological Innovation Projects in Shandong Province(2019JZZY010709)the Open Project of Liaocheng Universtiy Animal Husbandry Discipline(319312101-02)+1 种基金the Fundamental Research Funds for the Central Universities(2662020SKPY002)the Key Technology R&D Program of Hubei Province(2021BBA258).
文摘The black soldier fly(BSF),Hermetia illucens(Diptera:Stratiomyidae),is an insect commonly used for the bioconversion of various organic wastes.Not only can the BSF convert organic waste into macromolecular organic substances,such as insect pro-teins,but it can also lessen the pollution associated with these waste products by reducing ammonia emissions,for example.In this study,we measured the effects of adding fruit fermentation broth(Fer)and commercial lactic acid bacteria fermentation broth(Em)to kitchen waste(KW),as deodorizing auxiliary substances,on the growth performance of black soldier fly larvae(BSFL),the intestinal flora structure of BSFL,the ammonia emis-sion from the KW substrate,and the microbial community structure of the KW substrate.We found that the addition of Fer or Em increased the body weight of BSFL after 6 d of culture,increasing the growth rate by 9.96%and 7.96%,respectively.The addition of Fer not only reduced the pH of the KW substrate but also increased the relative abundance of probiotics,such as Lactobacillus,Lysinibacillus,and Vagococcus,which inhibited the growth of ammonifiers such as Bacillus,Oligella,Paenalcaligenes,Paenibacillus,Pseu-dogracilibacillus,and Pseudomonas,resulting in the reduction of ammonia emission in the KW substrate.Moreover,the addition of Fer or Em significantly increased the rela-tive abundances of Bacteroides,Campylobacter,Dysgonomonas,Enterococcus,and Ig-natzschineria in the gut of BSFL and increased the species diversity and richness in the K W substrate.Our findings provide a novel way to improve the conversion rate of organic waste and reduce the environmental pollution caused by BSF.
文摘With the advent of Internet services, big data and cloud computing, high-throughput computing has generated much research interest, especially on high-throughput cloud servers. However, three basic questions are still not satis-factorily answered： （1） What are the basic metrics （what throughput and high-throughput of what）？ （2） What are the main factors most beneficial to increasing throughput？ （3） Are there any fundamental constraints and how high can the throughput go？ This article addresses these issues by uti- lizing the fifty-year progress in Little＇s law, to reveal three fundamental relations among the seven basic quantities of throughput （2）, number of active threads （L）, waiting time （W）, system power （P）, thread energy （E）, Watts per thread to, threads per Joule 0. In addition to Little＇s law L = λW, we obtain P =λE and λ = Lto0, under reasonable assumptions. These equations help give a first order estimation of per- formance and power consumption targets for billion-thread cloud servers.
文摘Given the ability of building information models （BIM） to serve as a multidisciplinary data repository, this study attempts to explore and exploit the sustainability value of BIM in delivering buildings that require less energy for operations, emit tess carbon dioxide, and provide conducive living environments for occupants. This objective was attained by a critical and extensive literature review that covers the following： （1） building energy consumption, （2） building energy performance and analysis, and （3） BIM and energy assessment. Literature cited in this paper shows that linking an energy analysis toot with a BIM model has helped project design teams to predict and create optimized energy consumption by conducting building energy performance analysis utilizing key performance indicators on average thermal transmitters, resulting heat demand, lighting power, solar heat gains, and ventilation heat losses. An in-depth analysis was conducted on a completed BIM integrated construction project utilizing the Arboleda Project in the Dominican Republic to validate the aforementioned findings. Results show that the BIM-based energy analysis helped the design team attain the world＇s first positive energy building. This study concludes that linking an energy analysis tool with a BIM model helps to expedite the energy analysis process, provide more detailed and accurate results, and deliver energy-efficient buildings. This study further recommends that the adoption of level 2 BIM and BIM integration in energy optimization analysis must be demanded by building regulatory agencies for all projects regardless of procurement method （i.e., government funded or otherwise） or size.
基金supported by National Natural Science Foundation of China(No.51276172)
文摘Compared with single rotor small axial flow fans, dual-rotor small axial flow fans is better regarding the static characteristics. But the aerodynamic noise of dual-rotor small axial flow fans is worse than that of single rotor small axial flow fans. In order to improve aerodynamic noise of dual-rotor small axial flow fans, the pre-stage blades with different perforation numbers are designed in this research. The RANS equations and the standard k-e turbulence model as well as the FW-H noise model are used to simulate the flow field within the fan. Then, the aerodynamic performance of the fans with different perforation number is compared and analyzed. The results show that： （1） Compared to the prototype fan, the noise of fans with perforation blades is reduced. Additionally, the noise of the fans decreases with the increase of the number of perforations. （2） The vorticity value in the trailing edge of the pre-stage blades of perforated fans is reduced. It is found that the vorticity value in the trailing edge of the pre-stage blades decreases with the increase of the number of perforations. （3） Compared to the prototype fan, the total pressure rising and efficiency of the fans with perforation blades drop slightly.
