Instead of establishing mathematical hydraulic system models from physical laws usually done with the problems of complex modelling processes, low reliability and practicality caused by large uncertainties, a novel mo...Instead of establishing mathematical hydraulic system models from physical laws usually done with the problems of complex modelling processes, low reliability and practicality caused by large uncertainties, a novel modelling method for a highly nonlinear system of a hydraulic excavator is presented. Based on the data collected in the excavator＇s arms driving experiments, a data-based excavator dynamic model using Simplified Refined Instrumental Variable （SRIV） identification and estimation algorithms is established. The validity of the proposed data-based model is indirectly demonstrated by the performance of computer simulation and the.real machine motion control exoeriments.展开更多
Economic modeling that yields practical value must cater for effects caused by exogenous variables. AutoRegressive eXogenous approach (ARX) has been widely used in regional economic studies. Instrumental Variable Meth...Economic modeling that yields practical value must cater for effects caused by exogenous variables. AutoRegressive eXogenous approach (ARX) has been widely used in regional economic studies. Instrumental Variable Method is regarded as a preferential method to parametric estimation in ARX modeling. However, traditional instrumental variable methods can only handle single variable which has limited its capability. This paper presents an extended instrumental variable method (EIVM) which is based on multiple variables. This provides the capability of taking into account of exogenous variables and reflects better the economic activities. A case study is conducted, which illustrates the application of the EIVM in modeling Northeastern economy in China.展开更多
Early discharge policy, common in the developed countries, refers to the reduction of hospital length of stay as a way of reducing the cost of care. The effect of the policy on quality of care has received a lot of at...Early discharge policy, common in the developed countries, refers to the reduction of hospital length of stay as a way of reducing the cost of care. The effect of the policy on quality of care has received a lot of attention in the literature. Some of the earlier papers have ignored the endogeneity of length of stay in the readmission equation, an approach that could lead to inconsistent estimation. This study develops a statistical technique for the consistent estimation of the effect of the early discharge policy. An instrument that can be used extensively across different diagnostic groups is provided, hence solving the difficult problem of finding an instrument for length of stay. The exogeneity test in Gorgger (1990), the test for weak instruments in Staiger and Stock (1997) as well as the Hensen (1982) for over identification confirmed respectively that length of stay is endogenous the instrument is strong and the valid.展开更多
We reviewed the study by He et al,which investigates the genetic correlation between ulcerative colitis(UC)and anxiety using bidirectional Mendelian rando-mization.This study reveals a genetic link between UC and anxi...We reviewed the study by He et al,which investigates the genetic correlation between ulcerative colitis(UC)and anxiety using bidirectional Mendelian rando-mization.This study reveals a genetic link between UC and anxiety,diverging from prior research associating higher anxiety with Crohn’s disease.While the study's use of large-scale genome-wide association studies data is commendable,it faces limitations such as single nucleotide polymorphism selection biases,lack of multiple testing corrections,and a reliance on European populations.Future research should address these limitations,incorporate diverse populations,and explore psychotherapeutic interventions to improve UC management and patient outcomes.展开更多
Input variables selection(IVS) is proved to be pivotal in nonlinear dynamic system modeling. In order to optimize the model of the nonlinear dynamic system, a fuzzy modeling method for determining the premise structur...Input variables selection(IVS) is proved to be pivotal in nonlinear dynamic system modeling. In order to optimize the model of the nonlinear dynamic system, a fuzzy modeling method for determining the premise structure by selecting important inputs of the system is studied. Firstly, a simplified two stage fuzzy curves method is proposed, which is employed to sort all possible inputs by their relevance with outputs, select the important input variables of the system and identify the structure.Secondly, in order to reduce the complexity of the model, the standard fuzzy c-means clustering algorithm and the recursive least squares algorithm are used to identify the premise parameters and conclusion parameters, respectively. Then, the effectiveness of IVS is verified by two well-known issues. Finally, the proposed identification method is applied to a realistic variable load pneumatic system. The simulation experiments indi cate that the IVS method in this paper has a positive influence on the approximation performance of the Takagi-Sugeno(T-S) fuzzy modeling.展开更多
Background: There is an increased interest in developing better and more accurate methods to recognize and manage mental health problems in primary care settings. Abbreviated screening instruments for mental distress ...Background: There is an increased interest in developing better and more accurate methods to recognize and manage mental health problems in primary care settings. Abbreviated screening instruments for mental distress are useful tools for research and clinical practice. The present study seeks to investigate whether only a few questionnaire items from the Self-Reporting- Questionnaire-10 (SRQ-10) can be a robust method in the screening for Mental Distress in Primary Health care. Methods: We compared the screening accuracy of a short, five-item (SRQ-5) version of the SRQ-10 with that of the SRQ-20, General Health Questionnaire 12 (GHQ-12) using the DSM-IV axis as a gold standard and analyzed its performance in different diagnostic entities. We also assessed the correlation, sensitivity and specificity between the 4 instruments. All the instruments were administered to 400 primary health care attendees. Results: The estimated prevalence of mental distress was 13.6% in the study sample (Depression 11%, anxiety disorders 1.8%). The SRQ-5 was highly correlated to SRQ-10 (0.923, p < 0.001), SRQ-20 (0.764, p < 0.001) and only moderately correlated to GHQ-12 (0.417, p < 0.001). The SRQ-5 had high properties for identifying mental distress. The AUC for overall mental distress was 0.925 while that for depression and anxiety were 0.915 and 0.849 respectively. Conclusion: This validation showed that in moving from SRQ with 10 or 20 items to one with merely 5 items, we do not seem to lose the screening prowess of the instrument. The SRQ-5 represents a simplified and less time-consuming screening instrument with strong performance characteristics. We therefore recommend it for inclusion into existing patient assessment protocols, thus enhancing case finding at primary health care level.展开更多
文摘Instead of establishing mathematical hydraulic system models from physical laws usually done with the problems of complex modelling processes, low reliability and practicality caused by large uncertainties, a novel modelling method for a highly nonlinear system of a hydraulic excavator is presented. Based on the data collected in the excavator＇s arms driving experiments, a data-based excavator dynamic model using Simplified Refined Instrumental Variable （SRIV） identification and estimation algorithms is established. The validity of the proposed data-based model is indirectly demonstrated by the performance of computer simulation and the.real machine motion control exoeriments.
文摘Economic modeling that yields practical value must cater for effects caused by exogenous variables. AutoRegressive eXogenous approach (ARX) has been widely used in regional economic studies. Instrumental Variable Method is regarded as a preferential method to parametric estimation in ARX modeling. However, traditional instrumental variable methods can only handle single variable which has limited its capability. This paper presents an extended instrumental variable method (EIVM) which is based on multiple variables. This provides the capability of taking into account of exogenous variables and reflects better the economic activities. A case study is conducted, which illustrates the application of the EIVM in modeling Northeastern economy in China.
文摘Early discharge policy, common in the developed countries, refers to the reduction of hospital length of stay as a way of reducing the cost of care. The effect of the policy on quality of care has received a lot of attention in the literature. Some of the earlier papers have ignored the endogeneity of length of stay in the readmission equation, an approach that could lead to inconsistent estimation. This study develops a statistical technique for the consistent estimation of the effect of the early discharge policy. An instrument that can be used extensively across different diagnostic groups is provided, hence solving the difficult problem of finding an instrument for length of stay. The exogeneity test in Gorgger (1990), the test for weak instruments in Staiger and Stock (1997) as well as the Hensen (1982) for over identification confirmed respectively that length of stay is endogenous the instrument is strong and the valid.
基金Supported by Guangxi Training Program for Medical High-level Academic LeadersBose Talent Highland+3 种基金Building Projects of Guangxi Bagui Scholars,No.Guirencaiban[2024]-39Building Projects from the Key Laboratory of Molecular Pathology(Hepatobiliary Diseases)of Guangxi,the Key Laboratory of Tumor Molecular Pathology of Guangxi Colleges&UniversitiesClinical Key Specialty Building Project(For Pathology)of Guangxiand Nanshan District Health System Science and Technology Major Project,No.NSZD2024045.
文摘We reviewed the study by He et al,which investigates the genetic correlation between ulcerative colitis(UC)and anxiety using bidirectional Mendelian rando-mization.This study reveals a genetic link between UC and anxiety,diverging from prior research associating higher anxiety with Crohn’s disease.While the study's use of large-scale genome-wide association studies data is commendable,it faces limitations such as single nucleotide polymorphism selection biases,lack of multiple testing corrections,and a reliance on European populations.Future research should address these limitations,incorporate diverse populations,and explore psychotherapeutic interventions to improve UC management and patient outcomes.
基金This work was supported by the Natural Science Foundation of Hebei Province(F2019203505).
文摘Input variables selection(IVS) is proved to be pivotal in nonlinear dynamic system modeling. In order to optimize the model of the nonlinear dynamic system, a fuzzy modeling method for determining the premise structure by selecting important inputs of the system is studied. Firstly, a simplified two stage fuzzy curves method is proposed, which is employed to sort all possible inputs by their relevance with outputs, select the important input variables of the system and identify the structure.Secondly, in order to reduce the complexity of the model, the standard fuzzy c-means clustering algorithm and the recursive least squares algorithm are used to identify the premise parameters and conclusion parameters, respectively. Then, the effectiveness of IVS is verified by two well-known issues. Finally, the proposed identification method is applied to a realistic variable load pneumatic system. The simulation experiments indi cate that the IVS method in this paper has a positive influence on the approximation performance of the Takagi-Sugeno(T-S) fuzzy modeling.
文摘Background: There is an increased interest in developing better and more accurate methods to recognize and manage mental health problems in primary care settings. Abbreviated screening instruments for mental distress are useful tools for research and clinical practice. The present study seeks to investigate whether only a few questionnaire items from the Self-Reporting- Questionnaire-10 (SRQ-10) can be a robust method in the screening for Mental Distress in Primary Health care. Methods: We compared the screening accuracy of a short, five-item (SRQ-5) version of the SRQ-10 with that of the SRQ-20, General Health Questionnaire 12 (GHQ-12) using the DSM-IV axis as a gold standard and analyzed its performance in different diagnostic entities. We also assessed the correlation, sensitivity and specificity between the 4 instruments. All the instruments were administered to 400 primary health care attendees. Results: The estimated prevalence of mental distress was 13.6% in the study sample (Depression 11%, anxiety disorders 1.8%). The SRQ-5 was highly correlated to SRQ-10 (0.923, p < 0.001), SRQ-20 (0.764, p < 0.001) and only moderately correlated to GHQ-12 (0.417, p < 0.001). The SRQ-5 had high properties for identifying mental distress. The AUC for overall mental distress was 0.925 while that for depression and anxiety were 0.915 and 0.849 respectively. Conclusion: This validation showed that in moving from SRQ with 10 or 20 items to one with merely 5 items, we do not seem to lose the screening prowess of the instrument. The SRQ-5 represents a simplified and less time-consuming screening instrument with strong performance characteristics. We therefore recommend it for inclusion into existing patient assessment protocols, thus enhancing case finding at primary health care level.
