The existing spatially variant apodizations (SVAs) either cannot depress the sidelobes effectively or reduce the energy of the mainlobe.To improve this,a modified SVA (MSVA) is put forward in this paper,which expands ...The existing spatially variant apodizations (SVAs) either cannot depress the sidelobes effectively or reduce the energy of the mainlobe.To improve this,a modified SVA (MSVA) is put forward in this paper,which expands the traditional filter from 3-taps to 5-taps and sets relevant parameters according to different sampling rates to get the excellent result that satisfies constrained optimization theory.A method for synthetic aperture radar (SAR) sidelobe control based on MSVA is presented,which applies MSVA to range compression and azimuth compression to control sidelobes.This method which is available for any Nyquist sampling rate can both depress the sidelobes effectively and keep the energy of the mainlobe and the resolution of the image.The method can reduce sidelobe levels more effectively than classical amplitude weighting while maintaining the image resolution,as demonstrated by the result of the experiment.展开更多
基于断言的验证(Assertion Based Verification,ABV),是一种有价值的主流验证技术。断言特别适合于描述时序特性和因果特性。作为SystemVerilog的重要组成部分,SystemVerilogAssertion(SVA)提供了丰富的断言指令,能有效的提高验证测试...基于断言的验证(Assertion Based Verification,ABV),是一种有价值的主流验证技术。断言特别适合于描述时序特性和因果特性。作为SystemVerilog的重要组成部分,SystemVerilogAssertion(SVA)提供了丰富的断言指令,能有效的提高验证测试工作的质量和效率。文章首先介绍了断言验证语言SystemVerilogAssertion,并针对ARM公司的AMBA总线中的AHB仲裁器模块的设计,给出了一种基于断言的验证方法,采用SVA对其进行验证测试。测试仿真的结果表明,本文给出的方法的有效性和正确性。展开更多
Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudokno...Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudoknot)that have been demonstrated to be well conserved.However,it is still unclear whether each stem-loop subdomain,such as a single stem or loop,is also highly conserved.To clarify this issue in the present study,a set of 29 SVA cDNA clones were constructed by site-directed mutagenesis(SDM)on the IRES.The SDM-modified scenarios included:(1)stem-formed complementary sequences exchanging with each other;(2)loop transversion;(3)loop transition;and(4)point mutations.All cDNA clones were separately transfected into cells for rescuing viable viruses,whereas only four SVAs of interest could be recovered,and were genetically stable during 20 passages.One progeny grew significantly slower than the other three did.The dual-luciferase reporter assay showed that none of the SDM-modified IRESes significantly inhibited the IRES activity.Our previous study indicated that a single motif from any of the ten stem structures,if completely mutated,would cause the failure of virus recovery.Interestingly,our present study revealed three stem structures,whose individual complementary sequences could exchange with each other to rescue sequence-modifying SVAs.Moreover,one apical loop was demonstrated to have the ability to tolerate its own full-length transition,also having no impact on the recovery of sequence-modifying SVA.The present study suggested that not every stem-loop structure was strictly conserved in its conformation,while the full-length IRES itself was well conserved.This provides a new research direction on interaction between the IRES and many factors.展开更多
基金supported by the Knowledge Innovative Program of the Chinese Academy of Sciences (Grant No. 053Z170138)
文摘The existing spatially variant apodizations (SVAs) either cannot depress the sidelobes effectively or reduce the energy of the mainlobe.To improve this,a modified SVA (MSVA) is put forward in this paper,which expands the traditional filter from 3-taps to 5-taps and sets relevant parameters according to different sampling rates to get the excellent result that satisfies constrained optimization theory.A method for synthetic aperture radar (SAR) sidelobe control based on MSVA is presented,which applies MSVA to range compression and azimuth compression to control sidelobes.This method which is available for any Nyquist sampling rate can both depress the sidelobes effectively and keep the energy of the mainlobe and the resolution of the image.The method can reduce sidelobe levels more effectively than classical amplitude weighting while maintaining the image resolution,as demonstrated by the result of the experiment.
文摘基于断言的验证(Assertion Based Verification,ABV),是一种有价值的主流验证技术。断言特别适合于描述时序特性和因果特性。作为SystemVerilog的重要组成部分,SystemVerilogAssertion(SVA)提供了丰富的断言指令,能有效的提高验证测试工作的质量和效率。文章首先介绍了断言验证语言SystemVerilogAssertion,并针对ARM公司的AMBA总线中的AHB仲裁器模块的设计,给出了一种基于断言的验证方法,采用SVA对其进行验证测试。测试仿真的结果表明,本文给出的方法的有效性和正确性。
基金This work was supported by the National Natural Science Found ation of China(32273000)the Qingdao Demonstration Project for People-benefit from Science and Techniques,China(23-2-8-xdny-14nsh and 24-2-8-xdny-4-nsh)+1 种基金the National Program of Undergraduate Innovation and Entrepreneurship,China(202310435039)the Open Project Fund of State Key Laboratory of Microbial Technology,China(M2023-03)。
文摘Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudoknot)that have been demonstrated to be well conserved.However,it is still unclear whether each stem-loop subdomain,such as a single stem or loop,is also highly conserved.To clarify this issue in the present study,a set of 29 SVA cDNA clones were constructed by site-directed mutagenesis(SDM)on the IRES.The SDM-modified scenarios included:(1)stem-formed complementary sequences exchanging with each other;(2)loop transversion;(3)loop transition;and(4)point mutations.All cDNA clones were separately transfected into cells for rescuing viable viruses,whereas only four SVAs of interest could be recovered,and were genetically stable during 20 passages.One progeny grew significantly slower than the other three did.The dual-luciferase reporter assay showed that none of the SDM-modified IRESes significantly inhibited the IRES activity.Our previous study indicated that a single motif from any of the ten stem structures,if completely mutated,would cause the failure of virus recovery.Interestingly,our present study revealed three stem structures,whose individual complementary sequences could exchange with each other to rescue sequence-modifying SVAs.Moreover,one apical loop was demonstrated to have the ability to tolerate its own full-length transition,also having no impact on the recovery of sequence-modifying SVA.The present study suggested that not every stem-loop structure was strictly conserved in its conformation,while the full-length IRES itself was well conserved.This provides a new research direction on interaction between the IRES and many factors.
