Background:This study aimed to investigate the relationship between parental educational expectations and adolescent mental health problems,with academic pressure as a moderating variable.Methods:This study was based ...Background:This study aimed to investigate the relationship between parental educational expectations and adolescent mental health problems,with academic pressure as a moderating variable.Methods:This study was based on the baseline data of the China Education Panel Survey,which was collected within one school year during 2013–2014.It included 19,958 samples from seventh and ninth graders,who ranged from 11 to 18 years old.After removing missing values and conducting relevant data processing,the effective sample size for analysis was 16344.The OLS(Ordinary Least Squares)multiple linear regression analysis was used to examine the relationship between parental educational expectations,academic pressure,and adolescents’mental health problems.In addition,we established an interaction term between parents’educational expectations and academic pressure to investigate the moderating effect of academic stress.Results:The study found that adolescents whose parents had high educational expectations reported less mental health problems.(β=−0.195;p<0.001).Additionally,adolescents who had high academic pressure reported more mental health problems.(β=0.649;p<0.001).Furthermore,the study found that academic pressure had a significant moderating effect on the relationship between parental educational expectations and adolescents’mental health problems(β=0.082;p<0.001).Conclusion:Parental educational expectations had a close relationship with adolescents’mental health problems,and academic pressure moderated this relationship.For those adolescents with high levels of academic pressure,the association between high parental educational expectations and mental health problems became stronger.On the contrary,for those adolescents with low levels of academic pressure,the association between high parental educational expectations and mental health problems became weaker.These findings shed new light on how parental educational expectations affected adolescent mental health problems and had significant implications for their healthy development.展开更多
This study presents a kinematic calibration method for exoskeletal inertial motion capture (EI-MoCap) system with considering the random colored noise such as gyroscopic drift.In this method, the geometric parameters ...This study presents a kinematic calibration method for exoskeletal inertial motion capture (EI-MoCap) system with considering the random colored noise such as gyroscopic drift.In this method, the geometric parameters are calibrated by the traditional calibration method at first. Then, in order to calibrate the parameters affected by the random colored noise, the expectation maximization (EM) algorithm is introduced. Through the use of geometric parameters calibrated by the traditional calibration method, the iterations under the EM framework are decreased and the efficiency of the proposed method on embedded system is improved. The performance of the proposed kinematic calibration method is compared to the traditional calibration method. Furthermore, the feasibility of the proposed method is verified on the EI-MoCap system. The simulation and experiment demonstrate that the motion capture precision is significantly improved by 16.79%and 7.16%respectively in comparison to the traditional calibration method.展开更多
This paper considers the rational expectations model with multiplicative noise and input delay,where the system dynamics rely on the conditional expectations of future states.The main contribution is to obtain a suffi...This paper considers the rational expectations model with multiplicative noise and input delay,where the system dynamics rely on the conditional expectations of future states.The main contribution is to obtain a sufficient condition for the exact controllability of the rational expectations model.In particular,we derive a sufficient Gramian matrix condition and a rank condition for the delay-free case.The key is the solvability of the backward stochastic difference equations with input delay which is derived from the forward and backward stochastic system.展开更多
The Chinese economy continued to rebound and made solid progress in 2023,despite the complex international situation and numerous risks and challenges.The accelerated economic structural transformation and upgrade,cou...The Chinese economy continued to rebound and made solid progress in 2023,despite the complex international situation and numerous risks and challenges.The accelerated economic structural transformation and upgrade,coupled with increasing economic resilience,has resulted in various highlights.展开更多
How well is FOCAC meeting Africa’s aspirations for development?The idea of establishing the Forum on China-Africa Cooperation(FOCAC)in 2000 initially came from African countries,eager to coordinate and manage their r...How well is FOCAC meeting Africa’s aspirations for development?The idea of establishing the Forum on China-Africa Cooperation(FOCAC)in 2000 initially came from African countries,eager to coordinate and manage their relationship with China.展开更多
In this study, we aim to understand the characteristics of online group-buying consumers and to investigate salient factors which influence the continuance intention of online group-buying platforms (OGBP) to bridge...In this study, we aim to understand the characteristics of online group-buying consumers and to investigate salient factors which influence the continuance intention of online group-buying platforms (OGBP) to bridge this knowledge gap. An expectation-confirmation model of information systems (IS) continuance is adapted to construct a research model in online group-buying contexts. A total of 289 complete and valid responses were collected. Our findings contribute to academics and practitioners in two ways: Firstly, our respondents show that they are young (93% of the respondents' ages range between 19 and 28 years old), female (88% of the respondents), and thrifty (82% of the respondents' transaction amounts are below US$16). Secondly, based on our results, price performance expectations have a direct impact on confirmation. In addition, in contrast to the IS continuance model (Bhattacherjee, 2001), the effect of perceived usefulness on satisfaction is not supported. Thus, in online group-buying settings, confirmation is the key antecedent of satisfaction. Satisfaction and perceived usefulness are significantly associated with OGBP continuance intention. Consequently, in addition to offering a wide assortment of merchandise and a convenient online shopping experience to enhance customers' perceived usefulness of OGBP, OGBP managers should aim low-price marketing strategies at this female, young, thrifty and price-sensitive segment to transcend consumers' price expectations and attract consumers' continued intention to visit OGBP.展开更多
Over the past two years, China's olive Planting area was a bumper harvest year , extra virgin olive oil production has increased at rate of 30% an annual, the government, enterprises and farmers had should be present...Over the past two years, China's olive Planting area was a bumper harvest year , extra virgin olive oil production has increased at rate of 30% an annual, the government, enterprises and farmers had should be presented to the satisfaction of all the situation. However, a large number of farmer has listed to be bought of their fresh fruit , it was presented of 'queuing for salphenomenon, fruit can not be bought and pressed in time, farmer's enthusiasm was hurt and olive oil quality was reduced. In this regard, we had a comprehensive investigation and analysis of the current problems, combined with foreign research results, to researched the domestic and foreign olive oil market, has found our country disadvantages of in oil olive industry development and the existence question, and has carried on the forecast to our country oil olive industry development. Indicated that there is a lot of demand for olive oil consumer In China, and vigorously support at all levels of government, key factors restricting the healthy development of the industry had being resolved, speeding up the development of policies, technologies, talents,markets. The development prospect of olive industry is very broad.展开更多
The "expectations gap" signifies the differences between what the public expects from an audit and what the auditing profession prefers the audit objectives to be.Although the gap exists,it seems that the pr...The "expectations gap" signifies the differences between what the public expects from an audit and what the auditing profession prefers the audit objectives to be.Although the gap exists,it seems that the professions trust that it could be eliminated.In this paper,further evidence was provided to deny the above point by exploring the inevitability nature and the structure of the audit expectation gap.In addition,the author concludes that expectations gap cannot be eliminated;instead,the only thing can be done is to narrow down the gap.展开更多
We give a definition of relative entropy with respect to a sublinear expectation and establish large deviation principle for the empirical measures for independent random variables under the sublinear expectation.
Efficient massive MIMO detection for practical deployment, which is with spatially correlated channel and high-order modulation, is a challenging topic for the fifth generation mobile communication(5 G). In this paper...Efficient massive MIMO detection for practical deployment, which is with spatially correlated channel and high-order modulation, is a challenging topic for the fifth generation mobile communication(5 G). In this paper, we propose a lattice reduction aided expectation propagation(LRA-EP) algorithm for massive MIMO detection. LRA-EP applies expectation propagation in lattice reduced MIMO system to approach the distribution of lattice reduced constellation point by iterative refinement on its parameters(mean and covariance). The parameter refinement is based on the lattice reduced, well-conditioned MIMO channel. Numerical result shows that LRA-EP outperforms classic EP based MIMO detection(EPD) with 5~7 dB in terms of required signalto-noise ratio(SNR) for 1% packet error rate in spatially correlated channel for 256-QAM. We also show that LRA-EP has lower computation complexity than EPD.展开更多
Limit theorems for non-additive probabilities or non-linear expectations are challenging issues which have attracted a lot of interest recently.The purpose of this paper is to study the strong law of large numbers and...Limit theorems for non-additive probabilities or non-linear expectations are challenging issues which have attracted a lot of interest recently.The purpose of this paper is to study the strong law of large numbers and the law of the iterated logarithm for a sequence of random variables in a sub-linear expectation space under a concept of extended independence which is much weaker and easier to verify than the independence proposed by Peng[20].We introduce a concept of extended negative dependence which is an extension of the kind of weak independence and the extended negative independence relative to classical probability that has appeared in the recent literature.Powerful tools such as moment inequality and Kolmogorov’s exponential inequality are established for these kinds of extended negatively independent random variables,and these tools improve a lot upon those of Chen,Chen and Ng[1].The strong law of large numbers and the law of iterated logarithm are also obtained by applying these inequalities.展开更多
This paper has two aims. The first one is to investigate the existence of chaotic structures in the oil prices, expectations of investors and stock returns by combining the Lyapunov exponent and Kolmogorov entropy, an...This paper has two aims. The first one is to investigate the existence of chaotic structures in the oil prices, expectations of investors and stock returns by combining the Lyapunov exponent and Kolmogorov entropy, and the second one is to analyze the dependence behavior of oil prices, expectations of investors and stock returns from January 02, 1990, to June06, 2017. Lyapunov exponents and Kolmogorov entropy determined that the oil price and the stock return series exhibited chaotic behavior. TAR-TR-GARCH and TAR-TR-TGARCH copula methods were applied to study the co-movement among the selected variables. The results showed significant evidence of nonlinear tail dependence between the volatility of the oil prices, the expectations of investors and the stock returns. Further, upper and lower tail dependence and comovement between the analyzed series could not be rejected. Moreover, the TAR-TR-GARCH and TAR-TR-TGARCH copula methods revealed that the volatility of oil price had crucial effects on the stock returns and on the expectations of investors in the long run.展开更多
The concept of double conditional expectation is introduced. A series of properties for the double conditional expectation are obtained several convergence theorems and Jensen inequality are proved. Finally we discuss...The concept of double conditional expectation is introduced. A series of properties for the double conditional expectation are obtained several convergence theorems and Jensen inequality are proved. Finally we discuss the special cases and application for double conditional expectation. Key words double conditional expectation - covergence theorem - Jensen inequality - branching chain in random environment CLC number O 211.6 Foundation item: Supported by the National Science Foundation of China (10371092) and the Foundation of Wuhan UniversityBiography: HU Di-he (1935-), male, Professor, research direction: stochastic processes and random fractals.展开更多
The character and an algorithm about DRVIP( discrete random variable with interval probability) and the secured kind DRVFP (discrete random variable with crisp event-fuzzy probability) are researched. Using the fu...The character and an algorithm about DRVIP( discrete random variable with interval probability) and the secured kind DRVFP (discrete random variable with crisp event-fuzzy probability) are researched. Using the fuzzy resolution theorem, the solving mathematical expectation of a DRVFP can be translated into solving mathematical expectation of a series of RVIP. It is obvious that solving mathematical expectation of a DRVIP is a typical linear programming problem. A very functional calculating formula for solving mathematical expectation of DRVIP was obtained by using the Dantzig's simplex method. The example indicates that the result obtained by using the functional calculating formula fits together completely with the result obtained by using the linear programming method, but the process using the formula deduced is simpler.展开更多
Energy spectra of neutrons are important for identification of unknown neutron sources and for determination of the equivalent dose. Although standard energy spectra of neutrons are available in some situations, e.g.,...Energy spectra of neutrons are important for identification of unknown neutron sources and for determination of the equivalent dose. Although standard energy spectra of neutrons are available in some situations, e.g., for some radiotherapy treatment machines, they are unknown in other cases, e.g., for photoneutrons created in radiotherapy rooms and neutrons generated in nuclear reactors. In situations where neutron energy spectra need to be determined, unfolding the required neutron energy spectra using the Bonner sphere spectrometer (BSS) and nested neutron spectrometer (NNS) has been found promising. However, without any prior knowledge on the spectra, the unfolding process has remained a tedious task. In this work, a standalone numerical tool named ‘‘NRUunfold’’ was developed which could satisfactorily unfold neutron spectra for BSS or NNS, or any other systems using similar detection methodology. A generic and versatile algorithm based on maximum-likelihood expectation– maximization method was developed and benchmarked against the widely used STAY’SL algorithm which was based on the least squares method. The present method could output decent results in the absence of precisely calculated initial guess, although it was also remarked that employment of exceptionally bizarre initial spectra could lead to some unreasonable output spectra. The neutron count rates computed using the manufacturer’s response functions were used for sensitivity studies. The present NRUunfold code could be useful for neutron energy spectrum unfolding for BSS or NNS applications in the absence of a precisely calculated initial guess.展开更多
AIM To investigate whether minority ethnicity and the duration of education influence preoperative disability and expectations in patients undergoing total knee arthroplasty.METHODS We prospectively included 829 patie...AIM To investigate whether minority ethnicity and the duration of education influence preoperative disability and expectations in patients undergoing total knee arthroplasty.METHODS We prospectively included 829 patients undergoing primary unilateral total knee arthroplasty(TKA) from April 2013 to December 2014 at a single centre. Patients filled in pre-operative questionnaires with information regarding place of birth, duration of education, expectations for outcome of surgery and baseline characteristics. Patients were stratified based on ethnicity. Majority ethnicity was defined as born inthe study country and minority ethnicity was defined as born in any other country. Similarly, patients were stratified based on duration of education in groups defined as < 9 years, 9-12 years and > 12 years, respectively.RESULTS We found that 92.2% of patients were of majority ethnicity. We found that 24.5%, 44.8% and 30.8% of patients had an education of < 9 years, 9-12 years and > 12 years, respectively. The mean preoperative(preOP) oxford knee score(OKS) in the total population was 23.6. Patients of minority ethnicity had lower mean pre-OP OKS(18.6 vs 23.9, P < 0.001), higher pain levels(VAS 73.0 vs 58.7, P < 0.001), expected higher levels of post-OP pain(VAS 14.1 vs 6.1, P = 0.02) and of overall symptoms(VAS 16.6 vs 6.4, P = 0.006). Patients with > 12 years education had lower mean pre-OP OKS(21.5 vs 23.8 and 24.6, P < 0.001) and higher pre-OP VAS pain(65.4 vs 59.2 and 56.4, P < 0.001) compared to groups with shorter education. One year post-operative(post-OP) patients of minority ethnicity had lower mean OKS, higher pain and lower QoL. One year post-OP patients with > 12 years education reported higher pain compared to patients with shorter educations. However, the response-rate was low(44.6%), and therefore post-OP results were not considered to be significant.CONCLUSION Minority ethnicity and the duration of education influ-ence preoperative disability and expectation in patients undergoing TKA. This should be taken into account when patients are advised pre-operatively.展开更多
After reviewing the phylogeny of manufacturing activities and manufacturing science and summarizing the application actuality of digital manufacturing (DM) technologies in manufacturing, the theory supporting system o...After reviewing the phylogeny of manufacturing activities and manufacturing science and summarizing the application actuality of digital manufacturing (DM) technologies in manufacturing, the theory supporting system of digital manufacturing science (DMS) were deeply researched, including calculation manufacturing science and manufacturing informatics, bionics mechanics, manufacturing intelligent science and technical management science and so on. Then the connation of digital manufacturing technologies were dissertated, includes the digital technology set of product life-cycle, the digital manufacturing resources technology set, the manufacturing information technology set and technology characterizations of digital products. The developing directions of DMS in future were put forward at last.展开更多
The neutron spectrum unfolding by Bonner sphere spectrometer(BSS) is considered a complex multidimensional model,which requires complex mathematical methods to solve the first kind of Fredholm integral equation. In or...The neutron spectrum unfolding by Bonner sphere spectrometer(BSS) is considered a complex multidimensional model,which requires complex mathematical methods to solve the first kind of Fredholm integral equation. In order to solve the problem of the maximum likelihood expectation maximization(MLEM) algorithm which is easy to suffer the pitfalls of local optima and the particle swarm optimization(PSO) algorithm which is easy to get unreasonable flight direction and step length of particles, which leads to the invalid iteration and affect efficiency and accuracy, an improved PSO-MLEM algorithm, combined of PSO and MLEM algorithm, is proposed for neutron spectrum unfolding. The dynamic acceleration factor is used to balance the ability of global and local search, and improves the convergence speed and accuracy of the algorithm. Firstly, the Monte Carlo method was used to simulated the BSS to obtain the response function and count rates of BSS. In the simulation of count rate, four reference spectra from the IAEA Technical Report Series No. 403 were used as input parameters of the Monte Carlo method. The PSO-MLEM algorithm was used to unfold the neutron spectrum of the simulated data and was verified by the difference of the unfolded spectrum to the reference spectrum. Finally, the 252Cf neutron source was measured by BSS, and the PSO-MLEM algorithm was used to unfold the experimental neutron spectrum.Compared with maximum entropy deconvolution(MAXED), PSO and MLEM algorithm, the PSO-MLEM algorithm has fewer parameters and automatically adjusts the dynamic acceleration factor to solve the problem of local optima. The convergence speed of the PSO-MLEM algorithm is 1.4 times and 3.1 times that of the MLEM and PSO algorithms. Compared with PSO, MLEM and MAXED, the correlation coefficients of PSO-MLEM algorithm are increased by 33.1%, 33.5% and 1.9%, and the relative mean errors are decreased by 98.2%, 97.8% and 67.4%.展开更多
This research aims to test the housing price dynamics when considering heterogeneous boundedly rational expectations such as naive expectation, adaptive expectation and biased belief. The housing market is investigate...This research aims to test the housing price dynamics when considering heterogeneous boundedly rational expectations such as naive expectation, adaptive expectation and biased belief. The housing market is investigated as an evolutionary system with heterogeneous and competing expectations. The results show that the dynamics of the expected housing price varies substantially when heterogeneous expectations are considered together with some other endogenous factors. Simulation results explain some stylized phenomena such as equilibrium or oscillation, convergence or divergence, and over-shooting or under-shooting. Furthermore, the results suggest that variation of the proportion of groups of agents is basically dependent on the selected strategies. It also indicates that control policies should be chosen carefully in consistence with a unique real estate market during a unique period since certain parameter portfolio may increase or suppress oscillation.展开更多
基金the National Planning Office of Philosophy and Social Science,China (Grant Numbers 18ZDA133 & 23BSH105)ChinaAssociation of Higher Education (Grant Number 23LH0418).
文摘Background:This study aimed to investigate the relationship between parental educational expectations and adolescent mental health problems,with academic pressure as a moderating variable.Methods:This study was based on the baseline data of the China Education Panel Survey,which was collected within one school year during 2013–2014.It included 19,958 samples from seventh and ninth graders,who ranged from 11 to 18 years old.After removing missing values and conducting relevant data processing,the effective sample size for analysis was 16344.The OLS(Ordinary Least Squares)multiple linear regression analysis was used to examine the relationship between parental educational expectations,academic pressure,and adolescents’mental health problems.In addition,we established an interaction term between parents’educational expectations and academic pressure to investigate the moderating effect of academic stress.Results:The study found that adolescents whose parents had high educational expectations reported less mental health problems.(β=−0.195;p<0.001).Additionally,adolescents who had high academic pressure reported more mental health problems.(β=0.649;p<0.001).Furthermore,the study found that academic pressure had a significant moderating effect on the relationship between parental educational expectations and adolescents’mental health problems(β=0.082;p<0.001).Conclusion:Parental educational expectations had a close relationship with adolescents’mental health problems,and academic pressure moderated this relationship.For those adolescents with high levels of academic pressure,the association between high parental educational expectations and mental health problems became stronger.On the contrary,for those adolescents with low levels of academic pressure,the association between high parental educational expectations and mental health problems became weaker.These findings shed new light on how parental educational expectations affected adolescent mental health problems and had significant implications for their healthy development.
基金supported by the National Natural Science Foundation of China (61503392)。
文摘This study presents a kinematic calibration method for exoskeletal inertial motion capture (EI-MoCap) system with considering the random colored noise such as gyroscopic drift.In this method, the geometric parameters are calibrated by the traditional calibration method at first. Then, in order to calibrate the parameters affected by the random colored noise, the expectation maximization (EM) algorithm is introduced. Through the use of geometric parameters calibrated by the traditional calibration method, the iterations under the EM framework are decreased and the efficiency of the proposed method on embedded system is improved. The performance of the proposed kinematic calibration method is compared to the traditional calibration method. Furthermore, the feasibility of the proposed method is verified on the EI-MoCap system. The simulation and experiment demonstrate that the motion capture precision is significantly improved by 16.79%and 7.16%respectively in comparison to the traditional calibration method.
基金supported by the National Natural Science Foundation of China under Grants 61821004,62250056,62350710214,U23A20325,62350055the Natural Science Foundation of Shandong Province,China(ZR2021ZD14,ZR2021JQ24)+2 种基金High-level Talent Team Project of Qingdao West Coast New Area,China(RCTD-JC-2019-05)Key Research and Development Program of Shandong Province,China(2020CXGC01208)Science and Technology Project of Qingdao West Coast New Area,China(2019-32,2020-20,2020-1-4).
文摘This paper considers the rational expectations model with multiplicative noise and input delay,where the system dynamics rely on the conditional expectations of future states.The main contribution is to obtain a sufficient condition for the exact controllability of the rational expectations model.In particular,we derive a sufficient Gramian matrix condition and a rank condition for the delay-free case.The key is the solvability of the backward stochastic difference equations with input delay which is derived from the forward and backward stochastic system.
文摘The Chinese economy continued to rebound and made solid progress in 2023,despite the complex international situation and numerous risks and challenges.The accelerated economic structural transformation and upgrade,coupled with increasing economic resilience,has resulted in various highlights.
文摘How well is FOCAC meeting Africa’s aspirations for development?The idea of establishing the Forum on China-Africa Cooperation(FOCAC)in 2000 initially came from African countries,eager to coordinate and manage their relationship with China.
文摘In this study, we aim to understand the characteristics of online group-buying consumers and to investigate salient factors which influence the continuance intention of online group-buying platforms (OGBP) to bridge this knowledge gap. An expectation-confirmation model of information systems (IS) continuance is adapted to construct a research model in online group-buying contexts. A total of 289 complete and valid responses were collected. Our findings contribute to academics and practitioners in two ways: Firstly, our respondents show that they are young (93% of the respondents' ages range between 19 and 28 years old), female (88% of the respondents), and thrifty (82% of the respondents' transaction amounts are below US$16). Secondly, based on our results, price performance expectations have a direct impact on confirmation. In addition, in contrast to the IS continuance model (Bhattacherjee, 2001), the effect of perceived usefulness on satisfaction is not supported. Thus, in online group-buying settings, confirmation is the key antecedent of satisfaction. Satisfaction and perceived usefulness are significantly associated with OGBP continuance intention. Consequently, in addition to offering a wide assortment of merchandise and a convenient online shopping experience to enhance customers' perceived usefulness of OGBP, OGBP managers should aim low-price marketing strategies at this female, young, thrifty and price-sensitive segment to transcend consumers' price expectations and attract consumers' continued intention to visit OGBP.
基金Supported by Visiting Scholar Program of Light of the West by the Organization Department of the Central Committee(2016)Fundamental Research Funds for Central Public Welfare Research Institutes(2016K0273)~~
文摘Over the past two years, China's olive Planting area was a bumper harvest year , extra virgin olive oil production has increased at rate of 30% an annual, the government, enterprises and farmers had should be presented to the satisfaction of all the situation. However, a large number of farmer has listed to be bought of their fresh fruit , it was presented of 'queuing for salphenomenon, fruit can not be bought and pressed in time, farmer's enthusiasm was hurt and olive oil quality was reduced. In this regard, we had a comprehensive investigation and analysis of the current problems, combined with foreign research results, to researched the domestic and foreign olive oil market, has found our country disadvantages of in oil olive industry development and the existence question, and has carried on the forecast to our country oil olive industry development. Indicated that there is a lot of demand for olive oil consumer In China, and vigorously support at all levels of government, key factors restricting the healthy development of the industry had being resolved, speeding up the development of policies, technologies, talents,markets. The development prospect of olive industry is very broad.
文摘The "expectations gap" signifies the differences between what the public expects from an audit and what the auditing profession prefers the audit objectives to be.Although the gap exists,it seems that the professions trust that it could be eliminated.In this paper,further evidence was provided to deny the above point by exploring the inevitability nature and the structure of the audit expectation gap.In addition,the author concludes that expectations gap cannot be eliminated;instead,the only thing can be done is to narrow down the gap.
基金supported by the National Natural Science Foundation of China(11171262)the Specialized Research Fund for the Doctoral Program of Higher Education (200804860048)
文摘We give a definition of relative entropy with respect to a sublinear expectation and establish large deviation principle for the empirical measures for independent random variables under the sublinear expectation.
文摘Efficient massive MIMO detection for practical deployment, which is with spatially correlated channel and high-order modulation, is a challenging topic for the fifth generation mobile communication(5 G). In this paper, we propose a lattice reduction aided expectation propagation(LRA-EP) algorithm for massive MIMO detection. LRA-EP applies expectation propagation in lattice reduced MIMO system to approach the distribution of lattice reduced constellation point by iterative refinement on its parameters(mean and covariance). The parameter refinement is based on the lattice reduced, well-conditioned MIMO channel. Numerical result shows that LRA-EP outperforms classic EP based MIMO detection(EPD) with 5~7 dB in terms of required signalto-noise ratio(SNR) for 1% packet error rate in spatially correlated channel for 256-QAM. We also show that LRA-EP has lower computation complexity than EPD.
基金Research supported by grants from the NSF of China(1173101212031005)+2 种基金Ten Thousands Talents Plan of Zhejiang Province(2018R52042)NSF of Zhejiang Province(LZ21A010002)the Fundamental Research Funds for the Central Universities。
文摘Limit theorems for non-additive probabilities or non-linear expectations are challenging issues which have attracted a lot of interest recently.The purpose of this paper is to study the strong law of large numbers and the law of the iterated logarithm for a sequence of random variables in a sub-linear expectation space under a concept of extended independence which is much weaker and easier to verify than the independence proposed by Peng[20].We introduce a concept of extended negative dependence which is an extension of the kind of weak independence and the extended negative independence relative to classical probability that has appeared in the recent literature.Powerful tools such as moment inequality and Kolmogorov’s exponential inequality are established for these kinds of extended negatively independent random variables,and these tools improve a lot upon those of Chen,Chen and Ng[1].The strong law of large numbers and the law of iterated logarithm are also obtained by applying these inequalities.
文摘This paper has two aims. The first one is to investigate the existence of chaotic structures in the oil prices, expectations of investors and stock returns by combining the Lyapunov exponent and Kolmogorov entropy, and the second one is to analyze the dependence behavior of oil prices, expectations of investors and stock returns from January 02, 1990, to June06, 2017. Lyapunov exponents and Kolmogorov entropy determined that the oil price and the stock return series exhibited chaotic behavior. TAR-TR-GARCH and TAR-TR-TGARCH copula methods were applied to study the co-movement among the selected variables. The results showed significant evidence of nonlinear tail dependence between the volatility of the oil prices, the expectations of investors and the stock returns. Further, upper and lower tail dependence and comovement between the analyzed series could not be rejected. Moreover, the TAR-TR-GARCH and TAR-TR-TGARCH copula methods revealed that the volatility of oil price had crucial effects on the stock returns and on the expectations of investors in the long run.
文摘The concept of double conditional expectation is introduced. A series of properties for the double conditional expectation are obtained several convergence theorems and Jensen inequality are proved. Finally we discuss the special cases and application for double conditional expectation. Key words double conditional expectation - covergence theorem - Jensen inequality - branching chain in random environment CLC number O 211.6 Foundation item: Supported by the National Science Foundation of China (10371092) and the Foundation of Wuhan UniversityBiography: HU Di-he (1935-), male, Professor, research direction: stochastic processes and random fractals.
文摘The character and an algorithm about DRVIP( discrete random variable with interval probability) and the secured kind DRVFP (discrete random variable with crisp event-fuzzy probability) are researched. Using the fuzzy resolution theorem, the solving mathematical expectation of a DRVFP can be translated into solving mathematical expectation of a series of RVIP. It is obvious that solving mathematical expectation of a DRVIP is a typical linear programming problem. A very functional calculating formula for solving mathematical expectation of DRVIP was obtained by using the Dantzig's simplex method. The example indicates that the result obtained by using the functional calculating formula fits together completely with the result obtained by using the linear programming method, but the process using the formula deduced is simpler.
基金support from the Neutron computer cluster from the Department of Physics, City University of Hong Kong
文摘Energy spectra of neutrons are important for identification of unknown neutron sources and for determination of the equivalent dose. Although standard energy spectra of neutrons are available in some situations, e.g., for some radiotherapy treatment machines, they are unknown in other cases, e.g., for photoneutrons created in radiotherapy rooms and neutrons generated in nuclear reactors. In situations where neutron energy spectra need to be determined, unfolding the required neutron energy spectra using the Bonner sphere spectrometer (BSS) and nested neutron spectrometer (NNS) has been found promising. However, without any prior knowledge on the spectra, the unfolding process has remained a tedious task. In this work, a standalone numerical tool named ‘‘NRUunfold’’ was developed which could satisfactorily unfold neutron spectra for BSS or NNS, or any other systems using similar detection methodology. A generic and versatile algorithm based on maximum-likelihood expectation– maximization method was developed and benchmarked against the widely used STAY’SL algorithm which was based on the least squares method. The present method could output decent results in the absence of precisely calculated initial guess, although it was also remarked that employment of exceptionally bizarre initial spectra could lead to some unreasonable output spectra. The neutron count rates computed using the manufacturer’s response functions were used for sensitivity studies. The present NRUunfold code could be useful for neutron energy spectrum unfolding for BSS or NNS applications in the absence of a precisely calculated initial guess.
基金Supported by the Danish Rheumatism Association,No.R111-A2587
文摘AIM To investigate whether minority ethnicity and the duration of education influence preoperative disability and expectations in patients undergoing total knee arthroplasty.METHODS We prospectively included 829 patients undergoing primary unilateral total knee arthroplasty(TKA) from April 2013 to December 2014 at a single centre. Patients filled in pre-operative questionnaires with information regarding place of birth, duration of education, expectations for outcome of surgery and baseline characteristics. Patients were stratified based on ethnicity. Majority ethnicity was defined as born inthe study country and minority ethnicity was defined as born in any other country. Similarly, patients were stratified based on duration of education in groups defined as < 9 years, 9-12 years and > 12 years, respectively.RESULTS We found that 92.2% of patients were of majority ethnicity. We found that 24.5%, 44.8% and 30.8% of patients had an education of < 9 years, 9-12 years and > 12 years, respectively. The mean preoperative(preOP) oxford knee score(OKS) in the total population was 23.6. Patients of minority ethnicity had lower mean pre-OP OKS(18.6 vs 23.9, P < 0.001), higher pain levels(VAS 73.0 vs 58.7, P < 0.001), expected higher levels of post-OP pain(VAS 14.1 vs 6.1, P = 0.02) and of overall symptoms(VAS 16.6 vs 6.4, P = 0.006). Patients with > 12 years education had lower mean pre-OP OKS(21.5 vs 23.8 and 24.6, P < 0.001) and higher pre-OP VAS pain(65.4 vs 59.2 and 56.4, P < 0.001) compared to groups with shorter education. One year post-operative(post-OP) patients of minority ethnicity had lower mean OKS, higher pain and lower QoL. One year post-OP patients with > 12 years education reported higher pain compared to patients with shorter educations. However, the response-rate was low(44.6%), and therefore post-OP results were not considered to be significant.CONCLUSION Minority ethnicity and the duration of education influ-ence preoperative disability and expectation in patients undergoing TKA. This should be taken into account when patients are advised pre-operatively.
文摘After reviewing the phylogeny of manufacturing activities and manufacturing science and summarizing the application actuality of digital manufacturing (DM) technologies in manufacturing, the theory supporting system of digital manufacturing science (DMS) were deeply researched, including calculation manufacturing science and manufacturing informatics, bionics mechanics, manufacturing intelligent science and technical management science and so on. Then the connation of digital manufacturing technologies were dissertated, includes the digital technology set of product life-cycle, the digital manufacturing resources technology set, the manufacturing information technology set and technology characterizations of digital products. The developing directions of DMS in future were put forward at last.
基金supported by the National Natural science Foundation of China (No. 42127807)the Sichuan Science and Technology Program (No. 2020YJ0334)the Sichuan Science and Technology Breeding Program (No. 2022041)。
文摘The neutron spectrum unfolding by Bonner sphere spectrometer(BSS) is considered a complex multidimensional model,which requires complex mathematical methods to solve the first kind of Fredholm integral equation. In order to solve the problem of the maximum likelihood expectation maximization(MLEM) algorithm which is easy to suffer the pitfalls of local optima and the particle swarm optimization(PSO) algorithm which is easy to get unreasonable flight direction and step length of particles, which leads to the invalid iteration and affect efficiency and accuracy, an improved PSO-MLEM algorithm, combined of PSO and MLEM algorithm, is proposed for neutron spectrum unfolding. The dynamic acceleration factor is used to balance the ability of global and local search, and improves the convergence speed and accuracy of the algorithm. Firstly, the Monte Carlo method was used to simulated the BSS to obtain the response function and count rates of BSS. In the simulation of count rate, four reference spectra from the IAEA Technical Report Series No. 403 were used as input parameters of the Monte Carlo method. The PSO-MLEM algorithm was used to unfold the neutron spectrum of the simulated data and was verified by the difference of the unfolded spectrum to the reference spectrum. Finally, the 252Cf neutron source was measured by BSS, and the PSO-MLEM algorithm was used to unfold the experimental neutron spectrum.Compared with maximum entropy deconvolution(MAXED), PSO and MLEM algorithm, the PSO-MLEM algorithm has fewer parameters and automatically adjusts the dynamic acceleration factor to solve the problem of local optima. The convergence speed of the PSO-MLEM algorithm is 1.4 times and 3.1 times that of the MLEM and PSO algorithms. Compared with PSO, MLEM and MAXED, the correlation coefficients of PSO-MLEM algorithm are increased by 33.1%, 33.5% and 1.9%, and the relative mean errors are decreased by 98.2%, 97.8% and 67.4%.
文摘This research aims to test the housing price dynamics when considering heterogeneous boundedly rational expectations such as naive expectation, adaptive expectation and biased belief. The housing market is investigated as an evolutionary system with heterogeneous and competing expectations. The results show that the dynamics of the expected housing price varies substantially when heterogeneous expectations are considered together with some other endogenous factors. Simulation results explain some stylized phenomena such as equilibrium or oscillation, convergence or divergence, and over-shooting or under-shooting. Furthermore, the results suggest that variation of the proportion of groups of agents is basically dependent on the selected strategies. It also indicates that control policies should be chosen carefully in consistence with a unique real estate market during a unique period since certain parameter portfolio may increase or suppress oscillation.