We obtain the boundedness on Fp^α,q（R^n）for the Poisson summation and Gauss summation. Their maximal operators are proved to be bounded from Fp^α,q（R^n）to L∞（R^n）For the maximal operator of the Bochner-Riesz ...We obtain the boundedness on Fp^α,q（R^n）for the Poisson summation and Gauss summation. Their maximal operators are proved to be bounded from Fp^α,q（R^n）to L∞（R^n）For the maximal operator of the Bochner-Riesz summation, we prove that it is bounded from Fp^α,q（R^n）to L n-pα/pn,（0〈p≤ 1）∞（R^n）.展开更多
Long-period free oscillations provide robust information for the spatio-temporal characteristics of large earthquakes.In this study,we employ a normal-mode summation algorithm to generate threecomponent seismograms wi...Long-period free oscillations provide robust information for the spatio-temporal characteristics of large earthquakes.In this study,we employ a normal-mode summation algorithm to generate threecomponent seismograms within an aspherical,anelastic,and rotating Earth model,focusing on the excitation of seismic normal modes by the 2011 Tohoku megathrust earthquake.Specifically,we analyze the effects of seismic source parameters,including fault geometry,focal depth,and rupture duration.By comparing synthetic free oscillation spectra with observed data,we validate several source mechanisms and emphasize the need for horizontal observations to improve seismic mechanism inversions.Our quantitative analyses reveal that among fault geometry parameters,dip and slip angles have a more pronounced impact on excitation amplitudes than fault strikes.Certain fault configurations enhance the detectability of specific modes,underscoring the relationship between fault geometry and mode excitation.Normal modes also exhibit varying sensitivity to focal depth,with significant excitation amplitude changes at discontinuity boundaries.Additionally,we demonstrate that while rupture duration can be inferred by minimizing differences between observed and synthetic spectra,more extensive records and modes should be included.展开更多
This note concerns the rapid uniform convergence of Cesàro weighted Birkhoff averages via irrational rotations on tori under certain conditions,involving arbitrary polynomial and exponential convergence rates.We ...This note concerns the rapid uniform convergence of Cesàro weighted Birkhoff averages via irrational rotations on tori under certain conditions,involving arbitrary polynomial and exponential convergence rates.We discuss both finite dimensional and infinite dimensional cases,and give Diophantine rotations as examples.These provide the universality of rapid convergence for Cesàro weighted type,which is quite different from Lp(p>1)convergence for the unweighted one.We also show a certain optimality about our convergence rate.Besides,we introduce a multimodal weighted approach to adapt to the data sparsity,which still preserves exponential convergence.展开更多
BACKGROUND Bile leakage is a common complication following laparoscopic common bile duct exploration(LCBDE)with primary duct closure(PDC).Identifying and analyzing the risk factors associated with bile leakage is cruc...BACKGROUND Bile leakage is a common complication following laparoscopic common bile duct exploration(LCBDE)with primary duct closure(PDC).Identifying and analyzing the risk factors associated with bile leakage is crucial for improving surgical outcomes.AIM To explore the value analysis of common risk factors for bile leakage after LCBDE and PDC,with a focus on strict adherence to indications.METHODS Clinical data of 106 cases undergoing LCBDE+PDC in the Hepatobiliary and Pancreatic Surgery Department(Division 1)of Chuzhou First People’s Hospital from April 2019 to March 2024 were collected.Retrospective and multiple factor regression analysis were conducted on common risk factors for bile leakage.The change in surgical time was analyzed using the cumulative summation(CUSUM)method,and the minimum number of cases required to complete the learning curve for PDC was obtained based on the proposed fitting curve by identifying the CUSUM maximum value.RESULTS Multifactor logistic regression analysis showed that fibrinous inflammation and direct bilirubin/indirect bilirubin were significant independent high-risk factors for postoperative bile leakage(P<0.05).The time to drain removal and length of hospital stay in cases without bile leakage were significantly shorter than in cases with bile leakage(P<0.05),with statistical significance.The CUSUM method indicated that a minimum of 51 cases were required for the surgeon to complete the learning curve(P=0.023).CONCLUSION With a good assessment of duodenal papilla sphincter function,unobstructed bile-pancreatic duct convergence,exact stone clearance,and sufficient surgical experience to complete the learning curve,PDC remains the preferred method for bile duct closure and is worthy of clinical promotion.展开更多
The geological conditions for coal mining in China are complex,with various structural issues such as faults and collapsed columns seriously compromising the safety of coal mine production.In-seam wave exploration is ...The geological conditions for coal mining in China are complex,with various structural issues such as faults and collapsed columns seriously compromising the safety of coal mine production.In-seam wave exploration is an effective technique for acquiring detailed information on geological structures in coal seam working faces.However,the existing reflected in-seam wave imaging technique can no longer meet the exploration precision requirements,making it imperative to develop a new reflected in-seam wave imaging technique.This study applies the Gaussian beam summation(GBS)migration method to imaging coal seams'reflected in-seam wave data.Firstly,with regard to the characteristics of the reflected in-seam wave data,methods such as wavefield removal and enveloped superposition are employed for the corresponding wavefield separation,wave train compression and other processing of reflected in-seam waves.Thereafter,imaging is performed using the GBS migration technique.The feasibility and effectiveness of the proposed method for reflected in-seam wave imaging are validated by conducting GBS migration tests on 3D coal-seam fault models with different dip angles and throws.By applying the method to reflected in-seam wave data for an actual coal seam working face,accurate imaging of a fault structure is obtained,thereby validating its practicality.展开更多
To investigate the distribution and velocity attributes of gas hydrates in the northern continental slope of South China Sea, Guangzhou Marine Geological Survey conducted four-component （4C） ocean-bottom seismometer...To investigate the distribution and velocity attributes of gas hydrates in the northern continental slope of South China Sea, Guangzhou Marine Geological Survey conducted four-component （4C） ocean-bottom seismometer （OBS） surveys. A case study is presented to show the results of acquiring and processing OBS data for detecting gas hydrates. Key processing steps such as repositioning, reorientation, PZ summation, and mirror imaging are discussed. Repositioning and reorientation find the correct location and direction of nodes. PZ summation matches P- and Z-components and sums them to separate upgoing and downgoing waves. Upgoing waves are used in conventional imaging, whereas downgoing waves are used in mirror imaging. Mirror imaging uses the energy of the receiver ghost reflection to improve the illumination of shallow structures, where gas hydrates and the associated bottom-simulating reflections （BSRs） are located. We developed a new method of velocity analysis using mirror imaging. The proposed method is based on velocity scanning and iterative prestack time migration. The final imaging results are promising. When combined with the derived velocity field, we can characterize the BSR and shallow structures; hence, we conclude that using 4C OBS can reveal the distribution and velocity attributes of gas hydrates.展开更多
The effect of strong reflection interfaces, such as free surface, seabed, is strong; thus, the coupling of multiples and waves reduces the quality of ocean-bottom cable seismic data. Using the different polarity respo...The effect of strong reflection interfaces, such as free surface, seabed, is strong; thus, the coupling of multiples and waves reduces the quality of ocean-bottom cable seismic data. Using the different polarity response of hydrophones and geophones to downgoing wave fields, dual-sensor summation can eliminate receiver-side multiples, enhance primaries, and improve the resolution of seismic data. We present a dual-sensor summation method based on the equipoise pseudo-multichannel adaptive matching filter. Compared with traditional methods, the proposed method is totally data driven and does not depend on the reflection coefficient; moreover, good results are obtained using synthetic and real data.展开更多
We propose a system for remote measurement of low-energy radiation, which is implemented using an ARM board and a Zig Bee module. The ARM STM32 F103 board employs a horizontal and vertical moving CMOS camera for front...We propose a system for remote measurement of low-energy radiation, which is implemented using an ARM board and a Zig Bee module. The ARM STM32 F103 board employs a horizontal and vertical moving CMOS camera for front-end data acquisition. The camera can detect radiation over different coordinates given by latitude and longitude in a determined area. For image processing, we used the subtraction–summation algorithm based on gradient multiplication and edge detection. Compared to algorithms such as the max grayscale value, subtraction–summation, and whole summation, the improved subtraction–summation algorithm filters noise and removes the background grayscale value of the whole image to attain higher accuracy, stronger anti-interference ability, and better consistency to determine the radiation dose. We dedicated one port of the transmission module to send data through the STM32 F103 board, whereas another port is connected to the Zig Bee module for data reception. By employing this architecture, we achieved low power consumption and fast response in the remote data transmission.Overall, the proposed system performs the remote measurement of low-energy radiation with stability andreliability, which is required for critical scenarios such as the remote detection of nuclear radiation.展开更多
This paper investigates the problem of real-time estimation for one kind of linear time invariant systems which subject to limited communication capacity. The communication limitations include signal transmission dela...This paper investigates the problem of real-time estimation for one kind of linear time invariant systems which subject to limited communication capacity. The communication limitations include signal transmission delay, the out-of-sequence measurements and data packet dropout, which appear typically in a network environment. The kernel of filter design is equally to formularize the traditional Kalman filter as one linear weighted summation which is composed of the initial state estimate and all sequential sampled measurements. For it can adapt aforementioned information limitations, the linear weighted summation is then decomposed into two stages. One is a predict-estimator composed by all reached measurements, another is one compensator constructed by those time-delayed data. In the network environment, there are obvious differences between the new hybrid filter and those existing delayed Kalman filters. For example, the novel filter can be optimal in the sense of linear minimum mean square error as soon as all measurements available and has the lowest running time than these existing delayed filters. One simulation, including two cases, is utilized to illustrate the design procedures proposed in this paper.展开更多
Here introduced and studied are two formulaic classes consisting of various combinatorial algebraic identities and series summation formulas. The basic ideas include utilizing properly the △-operator and Stirling num...Here introduced and studied are two formulaic classes consisting of various combinatorial algebraic identities and series summation formulas. The basic ideas include utilizing properly the △-operator and Stirling numbers for some series transformations. A variety of classic formulas and remarkable identities are shown to be the members of the classes.展开更多
Instrumental and environmental disturbances do affect FG5 absolute gravimeter observations and the estimated gravity values, sometimes to the degree that entire measurement campaigns are discarded. We propose a method...Instrumental and environmental disturbances do affect FG5 absolute gravimeter observations and the estimated gravity values, sometimes to the degree that entire measurement campaigns are discarded. We propose a method which moves towards the re-assessment of previously discarded observations. Once an estimate of the frequency and amplitude of a disturbance in a FG5 data set exists, the proposed method can estimate its impact on the estimated gravity value. This is performed through a Gaussian Bell Summation approach of the functional relationship between disturbance frequency and standard deviation of gravity. The filtering of the identified disturbance is realized through a modification of the functional model of the equation of motion in the least squares adjustment of FG5 observations. The results reveal that the Gaussian Bell Summation approximates the frequency—gravity impact relationship sufficiently well with negligible uncertainties, while the accuracy of the detected disturbance frequency defines a limiting factor for the gravity impact estimation. A realistic disturbance of 15 Hz with an amplitude of 1.5 nm had an impact of ≈48 [μGal] on the gravity estimate. The proposed filter approach reduced the impact to ≈12 [μGal], with the remaining effect being almost entirely associated to the uncertainty in disturbance frequency detection.展开更多
In this paper, a novel image encryption algorithm is presented based on self-cited pixel summation. With the classical mechanism of permutation plus diffusion, a pixel summation of the plain image is employed to make ...In this paper, a novel image encryption algorithm is presented based on self-cited pixel summation. With the classical mechanism of permutation plus diffusion, a pixel summation of the plain image is employed to make a gravity influence on the pixel positions in the permutation stage. Then, for each pixel in every step of the diffusion stage, the pixel summation calculated from the permuted image is updated. The values from a chaotic sequence generated by an intertwining logistic map are selected by this summation. Consequently, the keystreams generated in both stages are dependent on both the plain image and the permuted image. Because of the sensitivity of the chaotic map to its initial conditions and the plain-imagedependent keystreams, any tiny change in the secret key or the plain image would lead to a significantly different cipher image. As a result, the proposed encryption algorithm is immune to the known plaintext attack（KPA） and the chosen plaintext attack（CPA）. Moreover, experimental simulations and security analyses show that the proposed permutationdiffusion encryption scheme can achieve a satisfactory level of security.展开更多
Ewald summation method, based on Non-Uniform FFTs (ENUF) to compute the electrostatic interactions and forces, is implemented in two different particle simulation schemes to model molecular and soft matter, in classic...Ewald summation method, based on Non-Uniform FFTs (ENUF) to compute the electrostatic interactions and forces, is implemented in two different particle simulation schemes to model molecular and soft matter, in classical all-atom Molecular Dynamics and in Dissipative Particle Dynamics for coarse-grained particles. The method combines the traditional Ewald method with a non-uniform fast Fourier transform library (NFFT), making it highly efficient. It scales linearly with the number of particles as , while being both robust and accurate. It conserves both energy and the momentum to float point accuracy. As demonstrated here, it is straight- forward to implement the method in existing computer simulation codes to treat the electrostatic interactions either between point-charges or charge distributions. It should be an attractive alternative to mesh-based Ewald methods.展开更多
This paper provides a pair of summation formulas for a kind of combinatorial series involvingak＋b m as a factor of the summand. The construction of formulas is based on a certain series transformation formula [2, 7, ...This paper provides a pair of summation formulas for a kind of combinatorial series involvingak＋b m as a factor of the summand. The construction of formulas is based on a certain series transformation formula [2, 7, 9] and by making use of the C-numbers [3]. Various consequences and examples including several remarkable classic identities are presented to illustrate some applications of the formulas obtained.展开更多
A stationary loudness model has been built up on the basis of the former ISO 226: 1987 concerning equal-loudness-level contours. The loudness and loudness level expressions derived in the study include the same parame...A stationary loudness model has been built up on the basis of the former ISO 226: 1987 concerning equal-loudness-level contours. The loudness and loudness level expressions derived in the study include the same parameters as used when determining the equal-loudness-level contours of the former ISO standard. However, as an additional main idea, a loudness summation rule has been proposed in the study. Moreover, the loudness expressions have been normalised to give the same values for people who have a similar sense of hearing. It has also been found that the loudness expressions include basically two different weightings. The first weighting is a conservative frequency weighting in the domain of sound pressure level, and the second weighting consists of coefficients applied to the weighted sound pressure levels. The latter have the greatest effect on the very low-frequency range. Finally, the paper includes a new way to use the A-weighting which takes into account the compressed character of the equal-loudness-level contours at the low frequency range. This method remarkably transforms the character of the A-weighting as a measure for low-frequency environmental noise.展开更多
Low cycle fatigue life consumption analysis was carried out in this work. Fatigue cycles accumulation method suitable even if engine is not often shut down was applied together with the modified universal sloped metho...Low cycle fatigue life consumption analysis was carried out in this work. Fatigue cycles accumulation method suitable even if engine is not often shut down was applied together with the modified universal sloped method for estimating fatigue cycles to failure. Damage summation rule was applied to estimate the fatigue damage accumulated over a given period of engine operation. The concept of fatigue factor which indicates how well engine is operated was introduced to make engine life tracking feasible. The developed fatigue life tracking method was incorporated in PYTHIA, Cranfield University in-house software and applied to 8 months of engine operation. The results obtained are similar to those of real engine operation. At a set power level, fatigue life decreases with increase in ambient temperature with the magnitude of decrease greater at higher power levels. The fatigue life tracking methodology developed could serve as a useful tool to engine operators.展开更多
The Euler–Maclaurin summation formula is generalized to a modified form by expanding the periodic Bernoulli polynomials as its Fourier series and taking cuts,which includes both the Euler–Maclaurin summation formula...The Euler–Maclaurin summation formula is generalized to a modified form by expanding the periodic Bernoulli polynomials as its Fourier series and taking cuts,which includes both the Euler–Maclaurin summation formula and the Poisson summation formula as special cases.By making use of the modified formula,a possible numerical summation method is obtained and the remainder can be controlled.The modified formula is also generalized from one dimension to two dimensions.Approximate expressions of partition functions of a classical particle in square well in 1D and 2D and that of a quantum rotator are obtained with error estimation.展开更多
The purpose of this study is to acquire some conditions that reveal existence and stability for solutions to a class of difference equations with non-integer orderμ∈(1,2].The required conditions are obtained by appl...The purpose of this study is to acquire some conditions that reveal existence and stability for solutions to a class of difference equations with non-integer orderμ∈(1,2].The required conditions are obtained by applying the technique of contraction principle for uniqueness and Schauder’s fixed point theorem for existence.Also,we establish some conditions under which the solution of the considered class of difference equations is generalized Ulam-Hyers-Rassias stable.Example for the illustration of results is given.展开更多
The classical countable summation type Hahn-Schur theorem is a famous result in summation theory and measure theory. An interesting problem is whether the theorem can be generalized to non-countable summation case? In...The classical countable summation type Hahn-Schur theorem is a famous result in summation theory and measure theory. An interesting problem is whether the theorem can be generalized to non-countable summation case? In this paper, we show that the answer is true.展开更多
基金Supported by the Zhejiang Postdoctoral Science Foundation of China(BSH1302046)the National Natural Science Foundation of China(11271330)the Zhejiang Natural Science Foundation of China(Y604563)
文摘We obtain the boundedness on Fp^α,q（R^n）for the Poisson summation and Gauss summation. Their maximal operators are proved to be bounded from Fp^α,q（R^n）to L∞（R^n）For the maximal operator of the Bochner-Riesz summation, we prove that it is bounded from Fp^α,q（R^n）to L n-pα/pn,（0〈p≤ 1）∞（R^n）.
基金supported by the National Natural ScienceFoundation of China(42204003,42274011,42388102,42192533,42192531)the Natural Science Foundation of Wuhan(2024040701010027)+1 种基金the Open Fund Supported by the State KeyLaboratory of Precision Geodesy,Innovation Academy for PrecisionMeasurement Science and Technology,Chinese Academy of Sci-ences(SKLGED2024-1-1)the Open Fund Supported by KeyLaboratory of Polar Environment Monitoring and Public Gover-nance(Wuhan University),Ministry of Education(202401)。
文摘Long-period free oscillations provide robust information for the spatio-temporal characteristics of large earthquakes.In this study,we employ a normal-mode summation algorithm to generate threecomponent seismograms within an aspherical,anelastic,and rotating Earth model,focusing on the excitation of seismic normal modes by the 2011 Tohoku megathrust earthquake.Specifically,we analyze the effects of seismic source parameters,including fault geometry,focal depth,and rupture duration.By comparing synthetic free oscillation spectra with observed data,we validate several source mechanisms and emphasize the need for horizontal observations to improve seismic mechanism inversions.Our quantitative analyses reveal that among fault geometry parameters,dip and slip angles have a more pronounced impact on excitation amplitudes than fault strikes.Certain fault configurations enhance the detectability of specific modes,underscoring the relationship between fault geometry and mode excitation.Normal modes also exhibit varying sensitivity to focal depth,with significant excitation amplitude changes at discontinuity boundaries.Additionally,we demonstrate that while rupture duration can be inferred by minimizing differences between observed and synthetic spectra,more extensive records and modes should be included.
基金Supported by National Natural Science Foundation of China(Grant Nos.12071175,12471183 and 12531009)。
文摘This note concerns the rapid uniform convergence of Cesàro weighted Birkhoff averages via irrational rotations on tori under certain conditions,involving arbitrary polynomial and exponential convergence rates.We discuss both finite dimensional and infinite dimensional cases,and give Diophantine rotations as examples.These provide the universality of rapid convergence for Cesàro weighted type,which is quite different from Lp(p>1)convergence for the unweighted one.We also show a certain optimality about our convergence rate.Besides,we introduce a multimodal weighted approach to adapt to the data sparsity,which still preserves exponential convergence.
基金Supported by the Wannan Medical College Teaching Hospital Special Application for Scientific Research,No.WK2023JXYY036the Anhui Provincial Translational Clinical Medical Research Special Application,No.202204295107020062.
文摘BACKGROUND Bile leakage is a common complication following laparoscopic common bile duct exploration(LCBDE)with primary duct closure(PDC).Identifying and analyzing the risk factors associated with bile leakage is crucial for improving surgical outcomes.AIM To explore the value analysis of common risk factors for bile leakage after LCBDE and PDC,with a focus on strict adherence to indications.METHODS Clinical data of 106 cases undergoing LCBDE+PDC in the Hepatobiliary and Pancreatic Surgery Department(Division 1)of Chuzhou First People’s Hospital from April 2019 to March 2024 were collected.Retrospective and multiple factor regression analysis were conducted on common risk factors for bile leakage.The change in surgical time was analyzed using the cumulative summation(CUSUM)method,and the minimum number of cases required to complete the learning curve for PDC was obtained based on the proposed fitting curve by identifying the CUSUM maximum value.RESULTS Multifactor logistic regression analysis showed that fibrinous inflammation and direct bilirubin/indirect bilirubin were significant independent high-risk factors for postoperative bile leakage(P<0.05).The time to drain removal and length of hospital stay in cases without bile leakage were significantly shorter than in cases with bile leakage(P<0.05),with statistical significance.The CUSUM method indicated that a minimum of 51 cases were required for the surgeon to complete the learning curve(P=0.023).CONCLUSION With a good assessment of duodenal papilla sphincter function,unobstructed bile-pancreatic duct convergence,exact stone clearance,and sufficient surgical experience to complete the learning curve,PDC remains the preferred method for bile duct closure and is worthy of clinical promotion.
基金supported by the National Natural Science Foundation of China(Grant No.42174157)the CAGS Research Fund(Grant No.JKY202216)the Chinese Geological Survey Project(Grant Nos.DD20230008,DD20233002).
文摘The geological conditions for coal mining in China are complex,with various structural issues such as faults and collapsed columns seriously compromising the safety of coal mine production.In-seam wave exploration is an effective technique for acquiring detailed information on geological structures in coal seam working faces.However,the existing reflected in-seam wave imaging technique can no longer meet the exploration precision requirements,making it imperative to develop a new reflected in-seam wave imaging technique.This study applies the Gaussian beam summation(GBS)migration method to imaging coal seams'reflected in-seam wave data.Firstly,with regard to the characteristics of the reflected in-seam wave data,methods such as wavefield removal and enveloped superposition are employed for the corresponding wavefield separation,wave train compression and other processing of reflected in-seam waves.Thereafter,imaging is performed using the GBS migration technique.The feasibility and effectiveness of the proposed method for reflected in-seam wave imaging are validated by conducting GBS migration tests on 3D coal-seam fault models with different dip angles and throws.By applying the method to reflected in-seam wave data for an actual coal seam working face,accurate imaging of a fault structure is obtained,thereby validating its practicality.
基金supported by the National Hi-tech Research and Development Program of China(863 Program)(Grant No.2013AA092501)the China Geological Survey Projects(Grant Nos.GZH201100303 and GZH201100305)
文摘To investigate the distribution and velocity attributes of gas hydrates in the northern continental slope of South China Sea, Guangzhou Marine Geological Survey conducted four-component （4C） ocean-bottom seismometer （OBS） surveys. A case study is presented to show the results of acquiring and processing OBS data for detecting gas hydrates. Key processing steps such as repositioning, reorientation, PZ summation, and mirror imaging are discussed. Repositioning and reorientation find the correct location and direction of nodes. PZ summation matches P- and Z-components and sums them to separate upgoing and downgoing waves. Upgoing waves are used in conventional imaging, whereas downgoing waves are used in mirror imaging. Mirror imaging uses the energy of the receiver ghost reflection to improve the illumination of shallow structures, where gas hydrates and the associated bottom-simulating reflections （BSRs） are located. We developed a new method of velocity analysis using mirror imaging. The proposed method is based on velocity scanning and iterative prestack time migration. The final imaging results are promising. When combined with the derived velocity field, we can characterize the BSR and shallow structures; hence, we conclude that using 4C OBS can reveal the distribution and velocity attributes of gas hydrates.
基金supported jointly by the National Science Foundation Project(Grant No.41176077 and 41230318)
文摘The effect of strong reflection interfaces, such as free surface, seabed, is strong; thus, the coupling of multiples and waves reduces the quality of ocean-bottom cable seismic data. Using the different polarity response of hydrophones and geophones to downgoing wave fields, dual-sensor summation can eliminate receiver-side multiples, enhance primaries, and improve the resolution of seismic data. We present a dual-sensor summation method based on the equipoise pseudo-multichannel adaptive matching filter. Compared with traditional methods, the proposed method is totally data driven and does not depend on the reflection coefficient; moreover, good results are obtained using synthetic and real data.
基金supported by the Plan for Scientific Innovation Talent of Henan Province(No.154100510007)the Program for Creative Export Mental Project of National Undergraduate Students(No.CEPNU 5101022000004)
文摘We propose a system for remote measurement of low-energy radiation, which is implemented using an ARM board and a Zig Bee module. The ARM STM32 F103 board employs a horizontal and vertical moving CMOS camera for front-end data acquisition. The camera can detect radiation over different coordinates given by latitude and longitude in a determined area. For image processing, we used the subtraction–summation algorithm based on gradient multiplication and edge detection. Compared to algorithms such as the max grayscale value, subtraction–summation, and whole summation, the improved subtraction–summation algorithm filters noise and removes the background grayscale value of the whole image to attain higher accuracy, stronger anti-interference ability, and better consistency to determine the radiation dose. We dedicated one port of the transmission module to send data through the STM32 F103 board, whereas another port is connected to the Zig Bee module for data reception. By employing this architecture, we achieved low power consumption and fast response in the remote data transmission.Overall, the proposed system performs the remote measurement of low-energy radiation with stability andreliability, which is required for critical scenarios such as the remote detection of nuclear radiation.
基金Supported by the National Natural Science Foundation of China (No.60804064,60772006)
文摘This paper investigates the problem of real-time estimation for one kind of linear time invariant systems which subject to limited communication capacity. The communication limitations include signal transmission delay, the out-of-sequence measurements and data packet dropout, which appear typically in a network environment. The kernel of filter design is equally to formularize the traditional Kalman filter as one linear weighted summation which is composed of the initial state estimate and all sequential sampled measurements. For it can adapt aforementioned information limitations, the linear weighted summation is then decomposed into two stages. One is a predict-estimator composed by all reached measurements, another is one compensator constructed by those time-delayed data. In the network environment, there are obvious differences between the new hybrid filter and those existing delayed Kalman filters. For example, the novel filter can be optimal in the sense of linear minimum mean square error as soon as all measurements available and has the lowest running time than these existing delayed filters. One simulation, including two cases, is utilized to illustrate the design procedures proposed in this paper.
文摘Here introduced and studied are two formulaic classes consisting of various combinatorial algebraic identities and series summation formulas. The basic ideas include utilizing properly the △-operator and Stirling numbers for some series transformations. A variety of classic formulas and remarkable identities are shown to be the members of the classes.
文摘Instrumental and environmental disturbances do affect FG5 absolute gravimeter observations and the estimated gravity values, sometimes to the degree that entire measurement campaigns are discarded. We propose a method which moves towards the re-assessment of previously discarded observations. Once an estimate of the frequency and amplitude of a disturbance in a FG5 data set exists, the proposed method can estimate its impact on the estimated gravity value. This is performed through a Gaussian Bell Summation approach of the functional relationship between disturbance frequency and standard deviation of gravity. The filtering of the identified disturbance is realized through a modification of the functional model of the equation of motion in the least squares adjustment of FG5 observations. The results reveal that the Gaussian Bell Summation approximates the frequency—gravity impact relationship sufficiently well with negligible uncertainties, while the accuracy of the detected disturbance frequency defines a limiting factor for the gravity impact estimation. A realistic disturbance of 15 Hz with an amplitude of 1.5 nm had an impact of ≈48 [μGal] on the gravity estimate. The proposed filter approach reduced the impact to ≈12 [μGal], with the remaining effect being almost entirely associated to the uncertainty in disturbance frequency detection.
基金supported by the National Natural Science Foundation of China(Grant Nos.61602124,61273021,11526057,and 11301091)the Natural Science Foundation of Guangdong Province,China(Grant Nos.2016A030310333,2015A030313614,and 2015A030313620)+3 种基金the Science & Technology Planning Projects of Zhanjiang City,China(Grant Nos.2015B01098 and 2015B01051)the Project Foundation of Chongqing Municipal Education Committee of China(Grant No.KJ1500501)the Program for Scientific Research Start-up Funds of Guangdong Ocean University of Chinathe Special Funding Program for Excellent Young Scholars of Guangdong Ocean University of China
文摘In this paper, a novel image encryption algorithm is presented based on self-cited pixel summation. With the classical mechanism of permutation plus diffusion, a pixel summation of the plain image is employed to make a gravity influence on the pixel positions in the permutation stage. Then, for each pixel in every step of the diffusion stage, the pixel summation calculated from the permuted image is updated. The values from a chaotic sequence generated by an intertwining logistic map are selected by this summation. Consequently, the keystreams generated in both stages are dependent on both the plain image and the permuted image. Because of the sensitivity of the chaotic map to its initial conditions and the plain-imagedependent keystreams, any tiny change in the secret key or the plain image would lead to a significantly different cipher image. As a result, the proposed encryption algorithm is immune to the known plaintext attack（KPA） and the chosen plaintext attack（CPA）. Moreover, experimental simulations and security analyses show that the proposed permutationdiffusion encryption scheme can achieve a satisfactory level of security.
文摘Ewald summation method, based on Non-Uniform FFTs (ENUF) to compute the electrostatic interactions and forces, is implemented in two different particle simulation schemes to model molecular and soft matter, in classical all-atom Molecular Dynamics and in Dissipative Particle Dynamics for coarse-grained particles. The method combines the traditional Ewald method with a non-uniform fast Fourier transform library (NFFT), making it highly efficient. It scales linearly with the number of particles as , while being both robust and accurate. It conserves both energy and the momentum to float point accuracy. As demonstrated here, it is straight- forward to implement the method in existing computer simulation codes to treat the electrostatic interactions either between point-charges or charge distributions. It should be an attractive alternative to mesh-based Ewald methods.
基金Supported by the National Natural Science Foundation of China (Grant No.11071183)
文摘This paper provides a pair of summation formulas for a kind of combinatorial series involvingak＋b m as a factor of the summand. The construction of formulas is based on a certain series transformation formula [2, 7, 9] and by making use of the C-numbers [3]. Various consequences and examples including several remarkable classic identities are presented to illustrate some applications of the formulas obtained.
文摘A stationary loudness model has been built up on the basis of the former ISO 226: 1987 concerning equal-loudness-level contours. The loudness and loudness level expressions derived in the study include the same parameters as used when determining the equal-loudness-level contours of the former ISO standard. However, as an additional main idea, a loudness summation rule has been proposed in the study. Moreover, the loudness expressions have been normalised to give the same values for people who have a similar sense of hearing. It has also been found that the loudness expressions include basically two different weightings. The first weighting is a conservative frequency weighting in the domain of sound pressure level, and the second weighting consists of coefficients applied to the weighted sound pressure levels. The latter have the greatest effect on the very low-frequency range. Finally, the paper includes a new way to use the A-weighting which takes into account the compressed character of the equal-loudness-level contours at the low frequency range. This method remarkably transforms the character of the A-weighting as a measure for low-frequency environmental noise.
文摘Low cycle fatigue life consumption analysis was carried out in this work. Fatigue cycles accumulation method suitable even if engine is not often shut down was applied together with the modified universal sloped method for estimating fatigue cycles to failure. Damage summation rule was applied to estimate the fatigue damage accumulated over a given period of engine operation. The concept of fatigue factor which indicates how well engine is operated was introduced to make engine life tracking feasible. The developed fatigue life tracking method was incorporated in PYTHIA, Cranfield University in-house software and applied to 8 months of engine operation. The results obtained are similar to those of real engine operation. At a set power level, fatigue life decreases with increase in ambient temperature with the magnitude of decrease greater at higher power levels. The fatigue life tracking methodology developed could serve as a useful tool to engine operators.
基金supported by the‘Qinggu project’in Tianjin University under the Grant No.1701the NSFC under the Grant No.s 11547043,11705125。
文摘The Euler–Maclaurin summation formula is generalized to a modified form by expanding the periodic Bernoulli polynomials as its Fourier series and taking cuts,which includes both the Euler–Maclaurin summation formula and the Poisson summation formula as special cases.By making use of the modified formula,a possible numerical summation method is obtained and the remainder can be controlled.The modified formula is also generalized from one dimension to two dimensions.Approximate expressions of partition functions of a classical particle in square well in 1D and 2D and that of a quantum rotator are obtained with error estimation.
文摘The purpose of this study is to acquire some conditions that reveal existence and stability for solutions to a class of difference equations with non-integer orderμ∈(1,2].The required conditions are obtained by applying the technique of contraction principle for uniqueness and Schauder’s fixed point theorem for existence.Also,we establish some conditions under which the solution of the considered class of difference equations is generalized Ulam-Hyers-Rassias stable.Example for the illustration of results is given.
基金Supported by Research Fund of Kumoh National Institute of Technology(M1100)
文摘The classical countable summation type Hahn-Schur theorem is a famous result in summation theory and measure theory. An interesting problem is whether the theorem can be generalized to non-countable summation case? In this paper, we show that the answer is true.
