Kinematic calibration under the expectation maximization framework for exoskeletal inertial motion capture system

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.

Parental Educational Expectations,Academic Pressure,and Adolescent Mental Health:An Empirical Study Based on CEPS Survey Data

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.

Exact controllability of rational expectations model with multiplicative noise and input delay

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.

Exceeding Expectations

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.

Keeping Commitments,Meeting Expectations

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.

The study of a neutron spectrum unfolding method based on particle swarm optimization combined with maximum likelihood expectation maximization

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%.

Self-Frustration of Expectations in Major Depressive Disorder: The Syncytiopathy Hypothesis of Depression Revisited

This paper is a further elaboration of my model of the pathophysiology of major depressive disorder focusing on imbalances of glial-neuronal interactions in tripartite synapses and the glial network (syncytium). Basically, it is proposed that the connexin proteins building gap junctions in the glial syncytium are underexpressed or dysfunctional in major depression, called syncytiopathy. As a compensatory effect the astrocytic receptors in tripartite synapses are overexpressed. This leads to protracted synaptic information processing because of a relative lack of neurotransmitter substances for the occupancy of astrocytic receptors. Based on a new biophysical formal description of astrocytic receptors as expectation variables it can be shown that the protracted processing of sensory information frustrate the full comprehension of the expected event, since it cannot be grasped in time. Moreover, expectation frustration may stress the glial syncytium aggravating memory impairment. This cyclic process of dysbalanced synaptic information processing is characterized as self-frustration of expectations explanatory for the main cognitive dysfunctions in major depression as slowing down processing speed, deficits in attention and working memory. The main result of the study is that patients with major depression cannot fully acknowledge the existence of an intended event.

Iterative Receiver for Orthogonal Time Frequency Space with Index Modulation via Structured Prior-Based Hybrid Belief and Expectation Propagation

Orthogonal Time Frequency Space(OTFS)signaling with index modulation(IM)is a promising transmission scheme characterized by high transmission efficiency for high mobility scenarios.In this paper,we study the receiver for coded OTFS-IM system.First,we construct the corresponding factor graph,on which the structured prior incorporating activation pattern constraint and channel coding is devised.Then we develop a iterative receiver via structured prior-based hybrid belief propagation(BP)and expectation propagation(EP)algorithm,named as StrBP-EP,for the coded OTFS-IM system.To reduce the computational complexity of discrete distribution introduced by structured prior,Gaussian approximation conducted by EP is adopted.To further reduce the complexity,we derive two variations of the proposed algorithm by using some approximations.Simulation results validate the superior performance of the proposed algorithm.

Complete moment convergence for ND random variables under the sub-linear expectations

In this article,we establish a general result on complete moment convergence for arrays of rowwise negatively dependent(ND)random variables under the sub-linear expectations.As applications,we can obtain a series of results on complete moment convergence for ND random variables under the sub-linear expectations.

The Effects of Job Insecurity, Emotional Exhaustion, and Met Expectations on Hotel Employees’ Pro-Environmental Behaviors: Test of a Serial Mediation Model

There are a plethora of empirical pieces about employees’pro-environmental behaviors.However,the extant literature has either ignored or not fully examined various factors(e.g.,negative or positive non-green workplace factors)that might affect employees’pro-environmental behaviors.Realizing these voids,the present paper proposes and tests a serial mediation model that examines the interrelationships of job insecurity,emotional exhaustion,met expectations,and proactive pro-environmental behavior.We used data gathered from hotel customer-contact employees with a time lag of one week and their direct supervisors in China.After presenting support for the psychometric properties of the measures via confirmatory analysis in LISREL 8.30,the abovementioned linkages were gauged using the PROCESS plug-in for statistical package for social sciences.The findings delineated support for the hypothesized associations.Specifically,emotional exhaustion and met expectations partly mediated the effect of job insecurity on proactive pro-environmental behavior.More importantly,emotional exhaustion and met expectations serially mediated the influence of job insecurity on proactive pro-environmental behavior.These findings have important theoretical implications as well as significant implications for diminishing job insecurity,managing emotional exhaustion,increasing met expectations,and enhancing ecofriendly behaviors.

医患共同决策对患者家属诊疗期望值及满意度的影响

应用病例对照研究方法对拟行冠状动脉旁路移植术的患者进行医患共同决策干预。研究发现,经过医患共同决策干预的患者和家属,沟通后对诊疗结果的期望值明显减低,且沟通诊疗期望值低于传统方式沟通的患者和家属;在满意度测评中,干预组满意度和患者参与满意度调查的比例高于对照组,且干预组患者主导的满意度得分高于对照组和干预组家属主导的满意度得分。积极应用医患共同决策能够合理调控患者及其家属对诊疗行为的期望值,提升患者满意度,值得在国内医疗机构推广。

老年膝骨性关节炎患者治疗期望及其影响因素分析

目的探讨老年膝骨性关节炎(knee osteoarthritis,KOA)患者治疗期望及其影响因素。方法将2021年10月至2022年12月180例老年KOA患者作为研究对象,采用可信度/期望问卷(CEQ)中期望量表评估治疗期望,并评估不同人口特征间治疗期望差异;采用多元线性回归分析老年KOA患者治疗期望的影响因素。结果所有老年KOA患者治疗期望得分(16.64±3.00)分,其中年龄>75岁、KOA严重程度Kellgren-Lawrence(KL)为Ⅲ~Ⅳ级、焦虑评分<8分、疼痛灾难化评分<38分者治疗期望得分较年龄60~75岁、KOA严重程度为Ⅰ~Ⅱ级、焦虑评分≥8分及疼痛灾难化评分≥38分者高(P<0.05)。以治疗期望为因变量,年龄、焦虑、KOA严重程度、疼痛灾难化为自变量进行多元线性逐步回归,结果显示,年龄、KOA严重程度与老年KOA患者治疗期望呈正相关(β=0.048、0.992),焦虑、疼痛灾难化与老年KOA患者治疗期望呈负相关(β=-0.272、-0.068)(P<0.05)。结论老年KOA患者治疗期望与年龄、焦虑程度、KOA严重程度及疼痛灾难化有关。

Exceeding Expectations

Despite of the negative impact of the COVID-19 pandemic,China’s economic growth remained stable in 2022,which will benefit China-Africa economic cooperation this year.China’s GDP growth reached 3 percent year on year in 2022,the National Bureau of Statistics said on 16 January.

The Current Situation and Future Expectationsof China's Pilot Boatsl

Pilots need to board the ship for pilotage,but there are risks or potential dangers in the transfer of pilot.The author reviewed the history of the development of pilot boats,analyzed the potential risks or dangers of transferring pilot,proposed that pilot boat shall have the function of ensuring the safety of pilot when embarking or disembarking the ships,some suggestions on the future design and manufacture of Chinese pilot boats are also given according to the advantages and disadvantages of domestic and foreign pilot boats.

不确定性中的确定性--中国经济风险识别

为了揭示不确定性冲击下中国经济风险的确定性规律,本文基于预期经济增速分布,将不确定性与经济增长纳入“在险增长”的统一框架,以刻画经济不确定性与金融不确定性对经济风险的异质性影响。研究发现:不确定性冲击下的经济风险具有明显的确定性特征,伴随着不确定性升高,经济下行风险显著增加,经济上行风险较为稳定;当不确定性较低时,经济增速的潜在波动空间相对狭小,当不确定性较高时,经济增速具有较大的波动空间;不确定性与经济增长之间存在“双向反馈”的溢出循环机制,能够加剧不确定性的实际冲击效应;经济不确定性与金融不确定性对经济风险具有明显的异质性影响,无论是就冲击强度还是持续周期而言,经济不确定性的影响均更为显著。

城市间房价分化的影响因素研究

面对一二三线城市房价增速的分化走势,“因城施策”逐渐成为主基调,为此需要准确识别不同城市房价分化的主要因素。本文综合使用XGBoost等机器学习方法以及SHAP值解释性方法,基于2009—2019年全国70个大中城市面板数据,测算并分析一二三线城市房价分化的主要因素。结果表明:(1)预期因素在多轮房价分化期间都起到重要驱动作用;(2)货币政策本身并不是房价分化的主要因素,但可以通过影响预期导致房价分化;(3)需求因素和供给因素本身也不是房价分化的主要因素,但也可以通过影响预期导致房价分化。有鉴于此,“因城施策”的关键在于稳定公众对房价的预期:一线城市应在控制土地成本的前提下适当增加住房供给,削弱由于供不应求所带来的房价上涨预期;二三线城市需进一步完善基础设施,提高教育、医疗和环境质量,改善居民购房需求,防范人口外流带来的房价下跌预期。

生鲜电商平台消费者购菜意愿多元提升路径及适配组态研究

基于南昌市519份调查数据,运用技术接受模型3和期望确认理论模型,采用fsQCA方法对生鲜电商平台消费者购菜意愿进行组态分析,探讨消费者购菜意愿适配组态的要素构成条件及提升策略。结果表明:单一条件变量均不是生鲜电商平台消费者购菜意愿的必要条件,说明变量间可能存在替代作用;存在乐趣性与顾客认可型路径、适应性与情感导向型路径、体验感与顾客评价型路径、个性化与挑战导向型路径、影响力与便利导向型路径等5条产生高购菜意愿的路径;其中,高主观规范和高满意度作为核心条件存在于4条路径中,对生鲜电商平台消费者产生购菜意愿发挥着更普适的作用。基于此,建议整合多元路径,根据组态效应调整购菜意愿提升策略;确保产品质量,提升售后服务,重视满意度的普适性作用;建立良好口碑,发挥社交圈的积极作用,以实现平台发展的良性循环。

政策感知、组织创新氛围与人才创新绩效——人才自我创新期待的中介作用

在创新驱动发展背景下,区域创新与组织创新的最终落脚点是人才创新。以人才自我创新期待为中介变量,结合东部城市调查数据构建结构方程模型,系统考察政策感知与组织创新氛围对人才创新绩效的作用机制。研究结果表明,政策感知和组织创新氛围均对人才创新绩效具有显著正向影响;人才自我创新期待在政策感知与人才创新绩效之间、组织创新氛围与人才创新绩效之间均发挥中介作用;与政策感知相比,组织创新氛围对人才创新绩效的影响更显著。上述研究结论为解释政策感知和组织创新氛围影响人才创新绩效的内在机理提供了新思路,有助于政策制定者和组织管理者通过激发人才自我创新期待提高创新绩效。

大股东减持影响战略激进度吗?

企业通过维持适当的战略激进度以实现稳中求进,进而筑牢企业高质量发展的基石是当前理论研究和管理实践的重点议题之一。本文基于委托代理理论,以2008—2020年中国A股上市公司为样本,关注大股东减持和战略激进度二者之间的关系以及管理层代理效率在其中的调节作用。研究结果显示,大股东减持能够提高战略激进度,减持比例越大,减持后的战略激进度越高;同时,代理效率在这一过程中发挥着负向调节作用。进一步研究结果表明,绩效期望差距和高管团队稳定性在大股东减持与战略激进度的关系中起部分中介作用。异质性分析结果显示,在管理者为男性的企业、管理者学历较高的企业、两职分离的企业和衰退期企业中,大股东减持对战略激进度的提升作用更为明显。本文拓展了企业战略激进度的影响因素研究,深化了有关大股东减持经济后果的探讨,为企业所有者作出科学决策、防范战略风险提供了一定的参考。

基于期望核密度离群因子的离群点检测算法

针对基于密度的离群点检测方法在不同分布的数据集上检测精度低的问题,提出了一种基于期望核密度离群因子的离群点检测算法。首先,引入k近邻和反向k近邻扩展邻域空间(ENS)代替传统的k邻域范围,更加全面地考虑数据对象的邻域信息;其次,在传统核密度估计(KDE)方法的基础上引入多元高斯函数,在扩展邻域空间内估计数据对象的密度,同时借鉴自适应核带宽的思想,更好地适应不同数据集的数据分布;然后,给出期望距离的概念,进一步区分局部离群点和位于低密度区域的正常点;最后,定义了期望核密度离群因子刻画数据对象离群程度。在人工数据集和真实数据集上对所提算法进行实验验证,并与部分传统算法进行对比,验证了所提算法的有效性。