As one of the most promising paradigms of integrated circuit design,the approximate circuit has aroused widespread concern in the scientific community.It takes advantage of the inherent error tolerance of some applica...As one of the most promising paradigms of integrated circuit design,the approximate circuit has aroused widespread concern in the scientific community.It takes advantage of the inherent error tolerance of some applications and relaxes the accuracy for reductions in area and power consumption.This paper aims to provide a comprehensive survey of reliability issues related to approximate circuits,which covers three concerns:error characteristic analysis,reliability and test,and reliable design involving approximate circuits.The error characteristic analysis is used to compare the outputs of the approximate circuit with those of its precise counterpart,which can help to find the most appropriate approximate design for a specific application in the large design space.With the approximate design getting close to physical realization,manufacturing defects and operational faults are inevitable;therefore,the reliability prediction and vulnerability test become increasingly important.However,the research on approximate circuit reliability and test is insufficient and needs more attention.Furtherly,although there is some existing work combining the approximate design with fault tolerant techniques,the reliability-enhancement approaches for approximate circuits are lacking.展开更多
As an emerging computing technology,approximate computing enables computing systems to utilize hardware resources efficiently.Recently,approximate arithmetic units have received extensive attention and have been emplo...As an emerging computing technology,approximate computing enables computing systems to utilize hardware resources efficiently.Recently,approximate arithmetic units have received extensive attention and have been employed as hardware modules to build approximate circuit systems,such as approximate accelerators.In order to make the approximate circuit system meet the application requirements,it is imperative to quickly estimate the error quality caused by the approximate unit,especially in the high-level synthesis of the approximate circuit.However,there are few studies in the literature on how to efficiently evaluate the errors in the approximate circuit system.Hence,this paper focuses on error evaluation techniques for circuit systems consisting of approximate adders and approximate multipliers,which are the key hardware components in fault-tolerant applications.In this paper,the characteristics of probability mass function(PMF)based estimation are analyzed initially,and then an optimization technique for PMF-based estimation is proposed with consideration of these features.Finally,experiments prove that the optimization technology can reduce the time required for PMF-based estimation and improve the estimation quality.展开更多
In this paper,an in-band and out-of-band microwave wireless power-transmission characteristic analysis of a slot ring radome based on an approximate analytical method is proposed.The main contribution of this paper is...In this paper,an in-band and out-of-band microwave wireless power-transmission characteristic analysis of a slot ring radome based on an approximate analytical method is proposed.The main contribution of this paper is that,in the approximate analysis of the ring radome,a unified expression of the incident field on the radome surface is derived with E-plane and H-plane scanning,and the ring is approximated as 30 segments of straight strips.Solving the corresponding 60×60 linear equations yields the electric current distribution along the ring strip.The magnetic current along the complementary slot ring is obtained by duality.Thanks to the fully analytical format of the current distribution,the microwave wireless power-transmission characteristics are efficiently calculated using Munk’s scheme.An example of a slot ring biplanar symmetric hybrid radome is used to verify the accuracy and efficiency of the proposed scheme.The central processing unit(CPU)time is about 690 s using Ansys HFSS software versus 2.82 s for the proposed method.展开更多
In recent years,Approximate Computing Circuits(ACCs)have been widely used in applications with intrinsic tolerance to errors.With the increased availability of approximate computing circuit approaches,reliability anal...In recent years,Approximate Computing Circuits(ACCs)have been widely used in applications with intrinsic tolerance to errors.With the increased availability of approximate computing circuit approaches,reliability analysis methods for assessing their fault vulnerability have become highly necessary.In this study,two accurate reliability evaluation methods for approximate computing circuits are proposed.The reliability of approximate computing circuits is calculated on the basis of the iterative Probabilistic Transfer Matrix(PTM)model.During the calculation,the correlation coefficients are derived and combined to deal with the correlation problem caused by fanout reconvergence.The accuracy and scalability of the two methods are verified using three sets of approximate computing circuit instances and more circuits in Evo Approx8 b,which is an approximate computing circuit open source library.Experimental results show that relative to the Monte Carlo simulation,the two methods achieve average error rates of 0.46%and 1.29%and time overheads of 0.002%and 0.1%.Different from the existing approaches to reliability estimation for approximate computing circuits based on the original PTM model,the proposed methods reduce the space overheads by nearly 50%and achieve time overheads of 1.78%and 2.19%.展开更多
The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time consta...The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time constants and simplifying the transfer functions for reg lines are alsopresented.展开更多
An equivalent circuit representation is presented for a set of coupled transmission lines. An ap- proximation of the hyperbolic secant function allows a simple derivation of a staged model that accounts for the comple...An equivalent circuit representation is presented for a set of coupled transmission lines. An ap- proximation of the hyperbolic secant function allows a simple derivation of a staged model that accounts for the complex frequency dependent parameters. The model converts the T-ladder network into a i-r-network with controlled sources. The equivalent circuit based approach presented here is not only intriguing but also enhances the computed accuracy and efficiency. Numerical simulations verify the accuracy of this approach for both time and frequency domain responses.展开更多
基金supported by the Natural Science Foundation of Shanghai under Grant No.20ZR1455900the State Key Laboratory of Computer Architecture(Institute of Computing Technology,Chinese Academy of Sciences)under Grant No.CARCHA202005.
文摘As one of the most promising paradigms of integrated circuit design,the approximate circuit has aroused widespread concern in the scientific community.It takes advantage of the inherent error tolerance of some applications and relaxes the accuracy for reductions in area and power consumption.This paper aims to provide a comprehensive survey of reliability issues related to approximate circuits,which covers three concerns:error characteristic analysis,reliability and test,and reliable design involving approximate circuits.The error characteristic analysis is used to compare the outputs of the approximate circuit with those of its precise counterpart,which can help to find the most appropriate approximate design for a specific application in the large design space.With the approximate design getting close to physical realization,manufacturing defects and operational faults are inevitable;therefore,the reliability prediction and vulnerability test become increasingly important.However,the research on approximate circuit reliability and test is insufficient and needs more attention.Furtherly,although there is some existing work combining the approximate design with fault tolerant techniques,the reliability-enhancement approaches for approximate circuits are lacking.
基金supported by the National Natural Science Foundation of China under Grant No.62022041the Fundamental Research Funds for the Central Universities of China under Grant No.NP2022103.
文摘As an emerging computing technology,approximate computing enables computing systems to utilize hardware resources efficiently.Recently,approximate arithmetic units have received extensive attention and have been employed as hardware modules to build approximate circuit systems,such as approximate accelerators.In order to make the approximate circuit system meet the application requirements,it is imperative to quickly estimate the error quality caused by the approximate unit,especially in the high-level synthesis of the approximate circuit.However,there are few studies in the literature on how to efficiently evaluate the errors in the approximate circuit system.Hence,this paper focuses on error evaluation techniques for circuit systems consisting of approximate adders and approximate multipliers,which are the key hardware components in fault-tolerant applications.In this paper,the characteristics of probability mass function(PMF)based estimation are analyzed initially,and then an optimization technique for PMF-based estimation is proposed with consideration of these features.Finally,experiments prove that the optimization technology can reduce the time required for PMF-based estimation and improve the estimation quality.
基金supported in part by the National Key Research and Development Program(2021YFF1500100)Key Basic Research of Basic Strengthening Program of the Science and Technology Commission(2020-JCJQ-ZD-068)。
文摘In this paper,an in-band and out-of-band microwave wireless power-transmission characteristic analysis of a slot ring radome based on an approximate analytical method is proposed.The main contribution of this paper is that,in the approximate analysis of the ring radome,a unified expression of the incident field on the radome surface is derived with E-plane and H-plane scanning,and the ring is approximated as 30 segments of straight strips.Solving the corresponding 60×60 linear equations yields the electric current distribution along the ring strip.The magnetic current along the complementary slot ring is obtained by duality.Thanks to the fully analytical format of the current distribution,the microwave wireless power-transmission characteristics are efficiently calculated using Munk’s scheme.An example of a slot ring biplanar symmetric hybrid radome is used to verify the accuracy and efficiency of the proposed scheme.The central processing unit(CPU)time is about 690 s using Ansys HFSS software versus 2.82 s for the proposed method.
基金supported by the National Natural Science Foundation of China(Nos.61432017 and 61772327)the Natural Science Foundation of Shanghai(Nos.20ZR1455900 and 20ZR1421600)+1 种基金the Qi'anxin National Engineering Laboratory for Big Data Collaborative Security Technology Open Project(No.QAX-201803)State Key Laboratory of Computer Architecture,Institute of Computing Technology,Chinese Academy of Sciences(No.CARCHA202005)。
文摘In recent years,Approximate Computing Circuits(ACCs)have been widely used in applications with intrinsic tolerance to errors.With the increased availability of approximate computing circuit approaches,reliability analysis methods for assessing their fault vulnerability have become highly necessary.In this study,two accurate reliability evaluation methods for approximate computing circuits are proposed.The reliability of approximate computing circuits is calculated on the basis of the iterative Probabilistic Transfer Matrix(PTM)model.During the calculation,the correlation coefficients are derived and combined to deal with the correlation problem caused by fanout reconvergence.The accuracy and scalability of the two methods are verified using three sets of approximate computing circuit instances and more circuits in Evo Approx8 b,which is an approximate computing circuit open source library.Experimental results show that relative to the Monte Carlo simulation,the two methods achieve average error rates of 0.46%and 1.29%and time overheads of 0.002%and 0.1%.Different from the existing approaches to reliability estimation for approximate computing circuits based on the original PTM model,the proposed methods reduce the space overheads by nearly 50%and achieve time overheads of 1.78%and 2.19%.
文摘The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time constants and simplifying the transfer functions for reg lines are alsopresented.
基金Supported by the National Key Basic Research and Development (973) Program of China (No. 2010CB327404)
文摘An equivalent circuit representation is presented for a set of coupled transmission lines. An ap- proximation of the hyperbolic secant function allows a simple derivation of a staged model that accounts for the complex frequency dependent parameters. The model converts the T-ladder network into a i-r-network with controlled sources. The equivalent circuit based approach presented here is not only intriguing but also enhances the computed accuracy and efficiency. Numerical simulations verify the accuracy of this approach for both time and frequency domain responses.
