染色质转座酶可及性测序(assay for transposase-accessible chromatin with high-throughput sequencing,ATAC-seq)诞生于2013年,具有比脱氧核糖核酸酶I超敏感位点测序(deoxyribonuclease I hypersensitive site sequencing, DNase-seq...染色质转座酶可及性测序(assay for transposase-accessible chromatin with high-throughput sequencing,ATAC-seq)诞生于2013年,具有比脱氧核糖核酸酶I超敏感位点测序(deoxyribonuclease I hypersensitive site sequencing, DNase-seq)和微球菌核酸酶敏感位点测序(micrococcal nuclease sequencing, MNase-seq)更快速、灵敏、简便的优点,是目前分析全基因组范围染色质开放区域的热点技术。通过该技术能获得染色质开放区域的相关信息,从而映射出转录因子等调控蛋白的结合区域和核小体定位等信息,对于研究表观遗传分子机制具有重要意义。本文比较了5种获取染色质开放区域技术的优缺点,重点介绍了ATAC-seq的原理和主要流程,描述了利用ATAC-seq技术研究染色质开放区域的发展概况以及ATAC-seq的相关应用,期望对真核生物全基因组水平的染色质开放区域研究、顺式调控元件鉴定以及遗传调控网络的解析等提供借鉴。展开更多
The trajectory of the compact torus(CT)within a tokamak discharge is crucial to fueling.In this study,we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tok...The trajectory of the compact torus(CT)within a tokamak discharge is crucial to fueling.In this study,we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges.This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks.For perpendicular injection along the tokamak's major radius direction from the outboard,CTs with the same injection parameters exhibited a 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered.In addition,we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks.Furthermore,this paper discusses schemes for the tangential injection of CT into tokamak discharges.The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations.Finally,the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced byΔEk=975.08 J by optimizing the injection angle for the CT injected into ITER.These results provide valuable insights for optimizing injection angles in fusion experiments.Our model closely represents actual experimental scenarios and can assist the design of CT parameters.展开更多
Federated learning(FL)is an emerging privacy-preserving distributed computing paradigm,enabling numerous clients to collaboratively train machine learning models without the necessity of transmitting clients’private ...Federated learning(FL)is an emerging privacy-preserving distributed computing paradigm,enabling numerous clients to collaboratively train machine learning models without the necessity of transmitting clients’private datasets to the central server.Unlike most existing research where the local datasets of clients are assumed to be unchanged over time throughout the whole FL process,our study addresses such scenarios in this paper where clients’datasets need to be updated periodically,and the server can incentivize clients to employ as fresh as possible datasets for local model training.Our primary objective is to design a client selection strategy to minimize the loss of the global model for FL loss within a constrained budget.To this end,we introduce the concept of“Age of Information”(AoI)to quantitatively assess the freshness of local datasets and conduct a theoretical analysis of the convergence bound in our AoI-aware FL system.Based on the convergence bound,we further formulate our problem as a restless multi-armed bandit(RMAB)problem.Next,we relax the RMAB problem and apply the Lagrangian Dual approach to decouple it into multiple subproblems.Finally,we propose a Whittle’s Index Based Client Selection(WICS)algorithm to determine the set of selected clients.In addition,comprehensive simulations substantiate that the proposed algorithm can effectively reduce training loss and enhance the learning accuracy compared with some state-of-the-art methods.展开更多
A multi-channel polarimeter-interferometer has been developed on the Keda Torus eXperiment(KTX)for the study of equilibrium dynamics and internal magnetic fluctuations.A three-wave technique based on terahertz solid-s...A multi-channel polarimeter-interferometer has been developed on the Keda Torus eXperiment(KTX)for the study of equilibrium dynamics and internal magnetic fluctuations.A three-wave technique based on terahertz solid-state sources(-650 GHz)is applied for simultaneous measurements of electron density and Faraday rotation angle.The output power of the microwave source is 2 mW.Faraday rotation effect using a rotating wave plate is tested with phase noise less than 0.8°,and the density phase noise is less than 0.9°.Measurement of Faraday rotation angle and density for discharges on KTX have demonstrated high sensitivity to internal MHD activities.展开更多
Ant Colony Optimization （AGO） has the character of positive feedback, distributed searching, and greedy searching. It is applicable to optimization grouping problems. Traditional cryptographic research is mainly bas...Ant Colony Optimization （AGO） has the character of positive feedback, distributed searching, and greedy searching. It is applicable to optimization grouping problems. Traditional cryptographic research is mainly based on pure mathematical methods which have complicated theories and algorithm. It seems that there is no relationship between cryptography and ACO. Actually, some problems in cryptography are due to optimization grouping problems that could be improved using an evolutionary algorithm. Therefore, this paper presents a new method of solving secure curve selection problems using ACO. We improved Complex Multiplication （CM） by combining Evolutionary Cryptography Theory with Weber polynomial solutions. We found that ACO makes full use of valid information generated from factorization and allocates computing resource reasonably. It greatly increases the performance of Weber polynomial solutions. Compared with traditional CM, which can only search one root once time, our new method searches all roots of the polynomial once, and the average time needed to search for one root reduces rapidly. The more roots are searched, the more ECs are obtained.展开更多
全球增暖背景下极端降水变化受到了温室气体、太阳辐射、气溶胶等自然与人为强迫因素的共同影响.本文基于“降水驱动与响应模式间比较计划”(A Precipitation Driver and Response Model Intercomparison Project,PDRMIP)提供的9个全球...全球增暖背景下极端降水变化受到了温室气体、太阳辐射、气溶胶等自然与人为强迫因素的共同影响.本文基于“降水驱动与响应模式间比较计划”(A Precipitation Driver and Response Model Intercomparison Project,PDRMIP)提供的9个全球气候模式模拟的针对5种不同因子(加倍二氧化碳、增加2%的太阳辐射、10倍黑碳、5倍硫酸盐、3倍甲烷)高强迫情景下的理想试验,利用气候变化检测和指数专家组(Expert Team on Climate Change Detection and Indices,ETCCDI)定义的4个降水指数,详细分析了不同外部强迫因子作用下全球极端降水的响应.结果表明,相比于平均降水,在5种强迫因子作用下极端降水指数均表现出更大的变化.与加倍二氧化碳相比,增加2%的太阳辐射、5倍硫酸盐气溶胶和3倍甲烷强迫下全球极端降水对温度变化的响应更加强烈,而10倍黑碳气溶胶强迫下的降水变化则表现出较强的模式间差异.在加倍二氧化碳、增加2%的太阳辐射和3倍甲烷强迫下,极端降水的变化表现相似的纬向分布特征,最强的降水响应出现在赤道地区;10倍黑碳、5倍硫酸盐气溶胶强迫下则表现出明显的南北半球差异.水汽收支诊断结果揭示了在高强迫情景下,二氧化碳、太阳辐射和甲烷强迫下热带地区更强烈的降水变化主要与热力作用有关,而动力作用可能是导致黑碳、硫酸盐气溶胶强迫下降水变化的主要原因.展开更多
文摘染色质转座酶可及性测序(assay for transposase-accessible chromatin with high-throughput sequencing,ATAC-seq)诞生于2013年,具有比脱氧核糖核酸酶I超敏感位点测序(deoxyribonuclease I hypersensitive site sequencing, DNase-seq)和微球菌核酸酶敏感位点测序(micrococcal nuclease sequencing, MNase-seq)更快速、灵敏、简便的优点,是目前分析全基因组范围染色质开放区域的热点技术。通过该技术能获得染色质开放区域的相关信息,从而映射出转录因子等调控蛋白的结合区域和核小体定位等信息,对于研究表观遗传分子机制具有重要意义。本文比较了5种获取染色质开放区域技术的优缺点,重点介绍了ATAC-seq的原理和主要流程,描述了利用ATAC-seq技术研究染色质开放区域的发展概况以及ATAC-seq的相关应用,期望对真核生物全基因组水平的染色质开放区域研究、顺式调控元件鉴定以及遗传调控网络的解析等提供借鉴。
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2022YFE03100004 and 2022YFE03060003)National Natural Science Foundation of China(Nos.12375226,12175227 and 11875255)the China Postdoctoral Science Foundation(No.2022M723066).
文摘The trajectory of the compact torus(CT)within a tokamak discharge is crucial to fueling.In this study,we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges.This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks.For perpendicular injection along the tokamak's major radius direction from the outboard,CTs with the same injection parameters exhibited a 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered.In addition,we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks.Furthermore,this paper discusses schemes for the tangential injection of CT into tokamak discharges.The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations.Finally,the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced byΔEk=975.08 J by optimizing the injection angle for the CT injected into ITER.These results provide valuable insights for optimizing injection angles in fusion experiments.Our model closely represents actual experimental scenarios and can assist the design of CT parameters.
基金supported by the National Natural Science Foundation of China under Grant No.62172386the Natural Science Foundation of Jiangsu Province of China under Grant No.BK20231212the Teaching Research Project of the Education Department of Anhui Province of China under Grant No.2021jyxm1738.
文摘Federated learning(FL)is an emerging privacy-preserving distributed computing paradigm,enabling numerous clients to collaboratively train machine learning models without the necessity of transmitting clients’private datasets to the central server.Unlike most existing research where the local datasets of clients are assumed to be unchanged over time throughout the whole FL process,our study addresses such scenarios in this paper where clients’datasets need to be updated periodically,and the server can incentivize clients to employ as fresh as possible datasets for local model training.Our primary objective is to design a client selection strategy to minimize the loss of the global model for FL loss within a constrained budget.To this end,we introduce the concept of“Age of Information”(AoI)to quantitatively assess the freshness of local datasets and conduct a theoretical analysis of the convergence bound in our AoI-aware FL system.Based on the convergence bound,we further formulate our problem as a restless multi-armed bandit(RMAB)problem.Next,we relax the RMAB problem and apply the Lagrangian Dual approach to decouple it into multiple subproblems.Finally,we propose a Whittle’s Index Based Client Selection(WICS)algorithm to determine the set of selected clients.In addition,comprehensive simulations substantiate that the proposed algorithm can effectively reduce training loss and enhance the learning accuracy compared with some state-of-the-art methods.
基金supported by National Natural Science Foundation of China(No.12175227)the Fundamental Research Funds for the Central Universities(No.USTC 20210079)the Collaborative Innovation Program of Hefei Science Center,CAS(No.2022HSC-CIP022)。
文摘A multi-channel polarimeter-interferometer has been developed on the Keda Torus eXperiment(KTX)for the study of equilibrium dynamics and internal magnetic fluctuations.A three-wave technique based on terahertz solid-state sources(-650 GHz)is applied for simultaneous measurements of electron density and Faraday rotation angle.The output power of the microwave source is 2 mW.Faraday rotation effect using a rotating wave plate is tested with phase noise less than 0.8°,and the density phase noise is less than 0.9°.Measurement of Faraday rotation angle and density for discharges on KTX have demonstrated high sensitivity to internal MHD activities.
基金supported by the National Natural Science Foundation of China (Nos.61332019, 61572304, 61272056, and 60970006)the Innovation Grant of Shanghai Municipal Education Commission (No.14ZZ089)Shanghai Key Laboratory of Specialty Fiber Optics and Optical Access Networks (No.SKLSFO2014-06)
文摘Ant Colony Optimization （AGO） has the character of positive feedback, distributed searching, and greedy searching. It is applicable to optimization grouping problems. Traditional cryptographic research is mainly based on pure mathematical methods which have complicated theories and algorithm. It seems that there is no relationship between cryptography and ACO. Actually, some problems in cryptography are due to optimization grouping problems that could be improved using an evolutionary algorithm. Therefore, this paper presents a new method of solving secure curve selection problems using ACO. We improved Complex Multiplication （CM） by combining Evolutionary Cryptography Theory with Weber polynomial solutions. We found that ACO makes full use of valid information generated from factorization and allocates computing resource reasonably. It greatly increases the performance of Weber polynomial solutions. Compared with traditional CM, which can only search one root once time, our new method searches all roots of the polynomial once, and the average time needed to search for one root reduces rapidly. The more roots are searched, the more ECs are obtained.
文摘全球增暖背景下极端降水变化受到了温室气体、太阳辐射、气溶胶等自然与人为强迫因素的共同影响.本文基于“降水驱动与响应模式间比较计划”(A Precipitation Driver and Response Model Intercomparison Project,PDRMIP)提供的9个全球气候模式模拟的针对5种不同因子(加倍二氧化碳、增加2%的太阳辐射、10倍黑碳、5倍硫酸盐、3倍甲烷)高强迫情景下的理想试验,利用气候变化检测和指数专家组(Expert Team on Climate Change Detection and Indices,ETCCDI)定义的4个降水指数,详细分析了不同外部强迫因子作用下全球极端降水的响应.结果表明,相比于平均降水,在5种强迫因子作用下极端降水指数均表现出更大的变化.与加倍二氧化碳相比,增加2%的太阳辐射、5倍硫酸盐气溶胶和3倍甲烷强迫下全球极端降水对温度变化的响应更加强烈,而10倍黑碳气溶胶强迫下的降水变化则表现出较强的模式间差异.在加倍二氧化碳、增加2%的太阳辐射和3倍甲烷强迫下,极端降水的变化表现相似的纬向分布特征,最强的降水响应出现在赤道地区;10倍黑碳、5倍硫酸盐气溶胶强迫下则表现出明显的南北半球差异.水汽收支诊断结果揭示了在高强迫情景下,二氧化碳、太阳辐射和甲烷强迫下热带地区更强烈的降水变化主要与热力作用有关,而动力作用可能是导致黑碳、硫酸盐气溶胶强迫下降水变化的主要原因.
