To enhance the robustness of LDMOS ESD protection devices, the influence of a source-bulk layout structure is analyzed by theoretical analysis and numerical simulation. Novel structures with varied source-bulk layout ...To enhance the robustness of LDMOS ESD protection devices, the influence of a source-bulk layout structure is analyzed by theoretical analysis and numerical simulation. Novel structures with varied source-bulk layout structures are fabricated and compared. As demonstrated by TLP testing, the optimized structure has an 88% larger It2 than a conventional one, and its Vtl is reduced from 55.53 to 50.69 V.展开更多
This study explores the interaction between spatial configuration,natural mobility,and visual accessibility in exhibition spaces,an area that remains underexplored.By integrating visibility graph analysis(VGA),intelli...This study explores the interaction between spatial configuration,natural mobility,and visual accessibility in exhibition spaces,an area that remains underexplored.By integrating visibility graph analysis(VGA),intelligent agent simulation(IAS),topological analysis,and field observation,the research examines functional layout and accessibility across four museums.Findings indicate that corridors and pathways,second only to exhibition halls,play a crucial role in spatial mobility.Composite layouts(e.g.,circular and L-shaped designs)exhibit superior mean depth and integration,yet connectivity and mean depth demonstrate a nonlinear relationship.Elongated or complex path turns increase cognitive load,complicating navigation,while open passageways promote smoother visitor distribution.Topological analysis effectively identifies optimal nodes,key locations,and path-turn efficiency under accessibility constraints.Visitor dwell time is shaped not only by exhibit content but also by spatial location,entry sequence,and visitor density.Results support the assumption that space syntax models align with realworld visitor flow patterns,yet predictive models fail to fully capture variations in mobility across different timeframes and behavioral contexts.These insights contribute to optimizing museum design for improved visitor experience and spatial efficiency.展开更多
In the wake of the research community gaining deep understanding about control-hijacking attacks,data-oriented attacks have emerged.Among data-oriented attacks,data structure manipulation attack(DSMA)is a major catego...In the wake of the research community gaining deep understanding about control-hijacking attacks,data-oriented attacks have emerged.Among data-oriented attacks,data structure manipulation attack(DSMA)is a major category.Pioneering research was conducted and shows that DSMA is able to circumvent the most effective defenses against control-hijacking attacks-DEP,ASLR and CFI.Up to this day,only two defense techniques have demonstrated their effectiveness:Data Flow Integrity(DFI)and Data Structure Layout Randomization(DSLR).However,DFI has high performance overhead,and dynamic DSLR has two main limitations.L-1:Randomizing a large set of data structures will significantly affect the performance.L-2:To be practical,only a fixed sub-set of data structures are randomized.In the case that the data structures targeted by an attack are not covered,dynamic DSLR is essentially noneffective.To address these two limitations,we propose a novel technique,feedback-control-based adaptive DSLR and build a system named SALADSPlus.SALADSPlus seeks to optimize the trade-off between security and cost through feedback control.Using a novel feedback-control-based adaptive algorithm extended from the Upper Confidence Bound(UCB)algorithm,the defender(controller)uses the feedbacks(cost-effectiveness)from previous randomization cycles to adaptively choose the set of data structures to randomize(the next action).Different from dynamic DSLR,the set of randomized data structures are adaptively changed based on the feedbacks.To obtain the feedbacks,SALADSPlus inserts canary in each data structure at the time of compilation.We have implemented SALADSPlus based on gcc-4.5.0.Experimental results show that the runtime overheads are 1.8%,3.7%,and 5.3% when the randomization cycles are selected as 10s,5s,and 1s respectively.展开更多
Existing methods of obtaining runtime feedback for structure data-layout optimization have several drawbacks, such as large overhead and difficulty composing training sets. As a result, structure data-layout optimizat...Existing methods of obtaining runtime feedback for structure data-layout optimization have several drawbacks, such as large overhead and difficulty composing training sets. As a result, structure data-layout optimization is not widely used. To overcome these drawbacks, a performance monitoring unit （PMU） sampling method was developed with much less overhead and better portability and usability. An algorithm was developed to correct incomplete and inaccurate PMU sampling. With the corrected PMU feedback, a structure data-layout optimizer achieved a 45.1% performance improvement compared to a design without data-layout optimization, which is 97.6% of the performance improvement achieved with instrumented feedback. Calculation of the PMU feedback increased the execution time by 12.3%, compared to the overhead for the instrumented feedback of 341.5%. Tests show that the PMU feedback is efficient and effective for structure data-layout optimization.展开更多
In China,traditional village layouts are dynamic,harmoniously integrated with the natural environment,and rich in unique cultural characteristics.However,rapidly constructed villages often lack professional design,res...In China,traditional village layouts are dynamic,harmoniously integrated with the natural environment,and rich in unique cultural characteristics.However,rapidly constructed villages often lack professional design,resulting in overly simple layouts and causing the villages to lose their traditional characteristics.Artiflcial intelligence holds the potential to alleviate this speciflc challenge.This study employs CGAN to generate comprehensive village layouts based on archetypal traditional villages,while also exploring parameters and network architectures to enhance result quality.The research address on traditional villages in southwestern Hubei,reflning generative factors,introducing image-based geographic scales,and employing machine vision to address data scarcity.The key flndings of this study includes:1)The research explores a class of AI-generated evaluation metrics suitable for village layout generation.2)It conflrms that the combination of the Unet_256 generator with the LSGAN architecture yields the best results in image generation.3)It is observed that the optimal generation results are achieved when the equivalent geographic scale of the image is 150 m×150 m.The study validates that GANs can be effectively applied in the village layout,producing layout results that incorporate traditional local experiences.This provides a novel approach to village layout.展开更多
Structure Data Layout Optimization （SDLO） is a prevailing compiler optimization technique to improve cache efficiency. Structure transformation is a critical step for SDLO. Diversity of transformation methods and ex...Structure Data Layout Optimization （SDLO） is a prevailing compiler optimization technique to improve cache efficiency. Structure transformation is a critical step for SDLO. Diversity of transformation methods and existence of complex data types are major challenges for structure transformation. We have designed and implemented STrans, a well-defined system which provides controllable and comprehensive functionality on structure transformation. Compared to known systems, it has less limitation on data types for transformation. In this paper we give formal definition of the approach STrans transforms data types. We have also designed Transformation Specification Language, a mini language to configure how to transform structures, which can be either manually tuned or generated by compiler. STrans supports three kinds of transformation methods, i.e., splitting, peeling, and pool-splitting, and works well on different combinations of compound data types. STrans is the transformation system used in ASLOP and is well tested for all benchmarks for ASLOR展开更多
The Intensity Heavy Ion Superconducting Linear Accelerator as the injector of the High Intensity Heavy- Ion Accelerator Facility, which is a new project proposed in China has been designed. One of the design options i...The Intensity Heavy Ion Superconducting Linear Accelerator as the injector of the High Intensity Heavy- Ion Accelerator Facility, which is a new project proposed in China has been designed. One of the design options in the low energy part is based on Quarter Wave Resonators （QWRs）. However, because of the unsymmetrical geometry of the cavity, there are dipole fields near the beam hole, which may steer the beam vertically, thus leading to emittance growth and beam loss. The effect of the dipole mode field is analyzed, and a method to overcome the beam steering effect by placing QWRs with opposite orientation is proposed in this paper. The simulation results show that the beam steering effect is reduced effectively by this method, and the deviation of the beam centroid is decreased from 2.87 mm to 0.1 mm. The emittance growth is also smaller.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.60906038,61076082)
文摘To enhance the robustness of LDMOS ESD protection devices, the influence of a source-bulk layout structure is analyzed by theoretical analysis and numerical simulation. Novel structures with varied source-bulk layout structures are fabricated and compared. As demonstrated by TLP testing, the optimized structure has an 88% larger It2 than a conventional one, and its Vtl is reduced from 55.53 to 50.69 V.
基金funded by the 2024 Individual Academic Enhancement Project of the University Project Pool,entitled“Reproduction and Reconstruction of Historical and Cultural Spaces in the Theoretical Perspective of the Field of Memory(Grant No.24XSC14)”the R&D Program of Beijing Municipal Education Commission(Grant No.SZ202110009003).
文摘This study explores the interaction between spatial configuration,natural mobility,and visual accessibility in exhibition spaces,an area that remains underexplored.By integrating visibility graph analysis(VGA),intelligent agent simulation(IAS),topological analysis,and field observation,the research examines functional layout and accessibility across four museums.Findings indicate that corridors and pathways,second only to exhibition halls,play a crucial role in spatial mobility.Composite layouts(e.g.,circular and L-shaped designs)exhibit superior mean depth and integration,yet connectivity and mean depth demonstrate a nonlinear relationship.Elongated or complex path turns increase cognitive load,complicating navigation,while open passageways promote smoother visitor distribution.Topological analysis effectively identifies optimal nodes,key locations,and path-turn efficiency under accessibility constraints.Visitor dwell time is shaped not only by exhibit content but also by spatial location,entry sequence,and visitor density.Results support the assumption that space syntax models align with realworld visitor flow patterns,yet predictive models fail to fully capture variations in mobility across different timeframes and behavioral contexts.These insights contribute to optimizing museum design for improved visitor experience and spatial efficiency.
基金supported by ARO W911NF-13-1-0421(MURI)NSF CNS-1422594NSF CNS-1505664.
文摘In the wake of the research community gaining deep understanding about control-hijacking attacks,data-oriented attacks have emerged.Among data-oriented attacks,data structure manipulation attack(DSMA)is a major category.Pioneering research was conducted and shows that DSMA is able to circumvent the most effective defenses against control-hijacking attacks-DEP,ASLR and CFI.Up to this day,only two defense techniques have demonstrated their effectiveness:Data Flow Integrity(DFI)and Data Structure Layout Randomization(DSLR).However,DFI has high performance overhead,and dynamic DSLR has two main limitations.L-1:Randomizing a large set of data structures will significantly affect the performance.L-2:To be practical,only a fixed sub-set of data structures are randomized.In the case that the data structures targeted by an attack are not covered,dynamic DSLR is essentially noneffective.To address these two limitations,we propose a novel technique,feedback-control-based adaptive DSLR and build a system named SALADSPlus.SALADSPlus seeks to optimize the trade-off between security and cost through feedback control.Using a novel feedback-control-based adaptive algorithm extended from the Upper Confidence Bound(UCB)algorithm,the defender(controller)uses the feedbacks(cost-effectiveness)from previous randomization cycles to adaptively choose the set of data structures to randomize(the next action).Different from dynamic DSLR,the set of randomized data structures are adaptively changed based on the feedbacks.To obtain the feedbacks,SALADSPlus inserts canary in each data structure at the time of compilation.We have implemented SALADSPlus based on gcc-4.5.0.Experimental results show that the runtime overheads are 1.8%,3.7%,and 5.3% when the randomization cycles are selected as 10s,5s,and 1s respectively.
文摘Existing methods of obtaining runtime feedback for structure data-layout optimization have several drawbacks, such as large overhead and difficulty composing training sets. As a result, structure data-layout optimization is not widely used. To overcome these drawbacks, a performance monitoring unit （PMU） sampling method was developed with much less overhead and better portability and usability. An algorithm was developed to correct incomplete and inaccurate PMU sampling. With the corrected PMU feedback, a structure data-layout optimizer achieved a 45.1% performance improvement compared to a design without data-layout optimization, which is 97.6% of the performance improvement achieved with instrumented feedback. Calculation of the PMU feedback increased the execution time by 12.3%, compared to the overhead for the instrumented feedback of 341.5%. Tests show that the PMU feedback is efficient and effective for structure data-layout optimization.
基金supported by the National Natural Science Foundation of China(Grant No.51978295)。
文摘In China,traditional village layouts are dynamic,harmoniously integrated with the natural environment,and rich in unique cultural characteristics.However,rapidly constructed villages often lack professional design,resulting in overly simple layouts and causing the villages to lose their traditional characteristics.Artiflcial intelligence holds the potential to alleviate this speciflc challenge.This study employs CGAN to generate comprehensive village layouts based on archetypal traditional villages,while also exploring parameters and network architectures to enhance result quality.The research address on traditional villages in southwestern Hubei,reflning generative factors,introducing image-based geographic scales,and employing machine vision to address data scarcity.The key flndings of this study includes:1)The research explores a class of AI-generated evaluation metrics suitable for village layout generation.2)It conflrms that the combination of the Unet_256 generator with the LSGAN architecture yields the best results in image generation.3)It is observed that the optimal generation results are achieved when the equivalent geographic scale of the image is 150 m×150 m.The study validates that GANs can be effectively applied in the village layout,producing layout results that incorporate traditional local experiences.This provides a novel approach to village layout.
基金supported by the National Natural Science Foundation of China(No.61133006)the National High-Tech Research and Development(863)Program of China(No.2012AA010901)
文摘Structure Data Layout Optimization （SDLO） is a prevailing compiler optimization technique to improve cache efficiency. Structure transformation is a critical step for SDLO. Diversity of transformation methods and existence of complex data types are major challenges for structure transformation. We have designed and implemented STrans, a well-defined system which provides controllable and comprehensive functionality on structure transformation. Compared to known systems, it has less limitation on data types for transformation. In this paper we give formal definition of the approach STrans transforms data types. We have also designed Transformation Specification Language, a mini language to configure how to transform structures, which can be either manually tuned or generated by compiler. STrans supports three kinds of transformation methods, i.e., splitting, peeling, and pool-splitting, and works well on different combinations of compound data types. STrans is the transformation system used in ASLOP and is well tested for all benchmarks for ASLOR
基金Supported by National Science Foundation of China(11079001)
文摘The Intensity Heavy Ion Superconducting Linear Accelerator as the injector of the High Intensity Heavy- Ion Accelerator Facility, which is a new project proposed in China has been designed. One of the design options in the low energy part is based on Quarter Wave Resonators （QWRs）. However, because of the unsymmetrical geometry of the cavity, there are dipole fields near the beam hole, which may steer the beam vertically, thus leading to emittance growth and beam loss. The effect of the dipole mode field is analyzed, and a method to overcome the beam steering effect by placing QWRs with opposite orientation is proposed in this paper. The simulation results show that the beam steering effect is reduced effectively by this method, and the deviation of the beam centroid is decreased from 2.87 mm to 0.1 mm. The emittance growth is also smaller.
