In the verification of wire electrical discharge machining （EDM）, the motion and the performance of the wire-EDM system are analyzed. The maximum inclining angle of the wire is calculated. The relevant judgment meth...In the verification of wire electrical discharge machining （EDM）, the motion and the performance of the wire-EDM system are analyzed. The maximum inclining angle of the wire is calculated. The relevant judgment methods are used for the collision between the wire, the fixture, and the machining table. In the wire-EDM simulation, the generated solid model can he used to investigate programming results and to check the machining accuracy. The generation algorithm for the solid model in the simulation is solved based on Boolean operations. The wire swept volume for each cutting step is united to form the entire wire swept volume. Through Boolean subtraction between the stock model and the entire wire swept volume, the solid model in the wire-EDM simulation is generated. The method is also suitable for the wire path intersection occurred in cutting cone-shaped models. Finally, experiments are given to prove the method.展开更多
AIM： To investigate preoperative factors associated with poor shore-term outcome after resection for multi- nodular hepatocellular carcinoma （HCC） and to assess the contraindication of patients for surgery, METHODS...AIM： To investigate preoperative factors associated with poor shore-term outcome after resection for multi- nodular hepatocellular carcinoma （HCC） and to assess the contraindication of patients for surgery, METHODS： We retrospectively analyzed 162 multi- nodular HCC patients with Child-Pugh A liver function who underwent surgical resection. The prognostic significance of preoperative factors was investigated by univariate analysis using the log-rank test and by multivariate analysis using the Cox proportional hazards model. Each independent risk factor was then assigned points to construct a scoring model to evaluate the in- dication for surgical intervention. A receiver operating characteristics （ROC） curve was constructed to assess the predictive ability of this system.RESULTS： The median overall survival was 38.3 mo （range： 3-80 too）, while the median disease-free sur- vival was 18.6 mo （range： 1-79 too）. The 1-year mor- tality was 14%. Independent prognostic risk factors of 1-year death included prealburnin 〈 170 rng/L [hazard ratio （HR）： 5.531, P 〈 0.001], alkaline phosphatase 〉 129 U/L （HR： 3.252, P = 0.005）, α fetoprotein 〉 20 μg/L （HR： 7.477, P = 0.011）, total tumor size 〉 8 cm （HR： 10.543; P 〈 0.001）, platelet count 〈 100×109/L （HR： 9.937, P 〈 0.001）, and y-glutamyl transpeptidase 〉 64 U/L （HR： 3.791, P 〈 0.001）. The scoring model had a strong ability to predict 1-year survival （area under ROC： 0.925, P 〈 0.001）. Patients with a score ≥5 had significantly poorer short-term outcome than those with a score 〈 5 （1-year mortality： 62% vs 5%, P 〈 0.001; 1-year recurrence rate： 86% vs 33%, P 〈 0.001）. Patients with score ≥5 had greater possibility of microvascular invasion （P 〈 0.001）, poor tumor dif- ferentiation （P = 0.003）, liver cirrhosis with small nod- ules （P 〈 0.001）, and intraoperative blood transfusion （P = 0.010）. CONCLUSION： A composite preoperative scoring model can be used as an indication of prognosis of HCC patients after surgical resection. Resection should be considered with caution in patients with a score ≥5, which indicates a contraindication for surgery.展开更多
Previous studies have shown that children learn from educational television; however, these studies have not explored how closely the educational content of the program is integrated to the narrative. The following st...Previous studies have shown that children learn from educational television; however, these studies have not explored how closely the educational content of the program is integrated to the narrative. The following study uses a systematic content analysis of 100 top-rated U.S. children＇s television programs to explore the tangential relationship （i.e., distance） of narrative and educational content through the lens of the capacity model--which is built upon three basic components： narrative content, educational content, and the distance between them. Programs were analyzed for distance by examining lesson clarity and integration, show type, target audience age, and station type. One-way ANOVAs indicates significant differences between the means of these variables. Programs targeting younger children presented educational content that was closely integrated into the plotline of the program and helped further the story. However, as the target audience aged, the educational content became more tangential to the narrative content and was less tied to the plotline of the program.展开更多
In cutting tool temperature experiment, a large number of related data could be available. In order to define the relationship among the experiment data, the nonlinear regressive curve of cutting tool temperature must...In cutting tool temperature experiment, a large number of related data could be available. In order to define the relationship among the experiment data, the nonlinear regressive curve of cutting tool temperature must be constructed based on the data. This paper proposes the Particle Swarm Optimization (PSO) algorithm for estimating the parameters such a curve. The PSO algorithm is an evolutional method based on a very simple concept. Comparison of PSO results with those of GA and LS methods showed that the PSO algorithm is more effective for estimating the parameters of the above curve.展开更多
The identification of Wiener systems has been an active research topic for years. A Wiener system is a series connection of a linear dynamic system followed by a static nonlinearity. The difficulty in obtaining a repr...The identification of Wiener systems has been an active research topic for years. A Wiener system is a series connection of a linear dynamic system followed by a static nonlinearity. The difficulty in obtaining a representation of the Wiener model is the need to estimate the nonlinear function from the input and output data, without the intermediate signal availability. This paper presents a methodology for the nonlinear system identification of a Wiener type model, using methods for subspaces and polynomials of Chebyshev. The subspace methods used are MOESP （multivariable output-error state space） and N4SID （numerical algorithms for subspace state space system identification）. A simulated example is presented to compare the performance of these algorithms.展开更多
In this paper, firstly, a basic nonlinear magnetic network model considering iron saturations is proposed for a three-phase 12-stator-slot/10-rotor-pole flux-switching permanent magnet(FSPM) machine. This model is bui...In this paper, firstly, a basic nonlinear magnetic network model considering iron saturations is proposed for a three-phase 12-stator-slot/10-rotor-pole flux-switching permanent magnet(FSPM) machine. This model is built under cylindrical coordinates and enables the open-circuit air-gap flux-density distributions, phase permanent magnet(PM) flux-linkage, and electromotive-force(EMF) to be predicted with acceptable accuracy. However, large discrepancies are found in the predictions of armature inductances. Then, the basic model is modified by taking into account the localized saturation effect. As a result, the electromagnetic performance can be predicted more accurately, especially for the air-gap flux-density distributions. Furthermore, two improved models are proposed by adding bypass-bridge branches in stator network, to enhance the calculating accuracy of both saturated and unsaturated armature inductances. Finally, the predicted results from the four magnetic network models are validated by both 2D finite element analysis(FEA) and experimental measurements on a machine prototype. Overall, comparisons indicate that the model with bypass-bridge branches between stator teeth and back irons exhibits best performances.展开更多
文摘In the verification of wire electrical discharge machining （EDM）, the motion and the performance of the wire-EDM system are analyzed. The maximum inclining angle of the wire is calculated. The relevant judgment methods are used for the collision between the wire, the fixture, and the machining table. In the wire-EDM simulation, the generated solid model can he used to investigate programming results and to check the machining accuracy. The generation algorithm for the solid model in the simulation is solved based on Boolean operations. The wire swept volume for each cutting step is united to form the entire wire swept volume. Through Boolean subtraction between the stock model and the entire wire swept volume, the solid model in the wire-EDM simulation is generated. The method is also suitable for the wire path intersection occurred in cutting cone-shaped models. Finally, experiments are given to prove the method.
文摘AIM： To investigate preoperative factors associated with poor shore-term outcome after resection for multi- nodular hepatocellular carcinoma （HCC） and to assess the contraindication of patients for surgery, METHODS： We retrospectively analyzed 162 multi- nodular HCC patients with Child-Pugh A liver function who underwent surgical resection. The prognostic significance of preoperative factors was investigated by univariate analysis using the log-rank test and by multivariate analysis using the Cox proportional hazards model. Each independent risk factor was then assigned points to construct a scoring model to evaluate the in- dication for surgical intervention. A receiver operating characteristics （ROC） curve was constructed to assess the predictive ability of this system.RESULTS： The median overall survival was 38.3 mo （range： 3-80 too）, while the median disease-free sur- vival was 18.6 mo （range： 1-79 too）. The 1-year mor- tality was 14%. Independent prognostic risk factors of 1-year death included prealburnin 〈 170 rng/L [hazard ratio （HR）： 5.531, P 〈 0.001], alkaline phosphatase 〉 129 U/L （HR： 3.252, P = 0.005）, α fetoprotein 〉 20 μg/L （HR： 7.477, P = 0.011）, total tumor size 〉 8 cm （HR： 10.543; P 〈 0.001）, platelet count 〈 100×109/L （HR： 9.937, P 〈 0.001）, and y-glutamyl transpeptidase 〉 64 U/L （HR： 3.791, P 〈 0.001）. The scoring model had a strong ability to predict 1-year survival （area under ROC： 0.925, P 〈 0.001）. Patients with a score ≥5 had significantly poorer short-term outcome than those with a score 〈 5 （1-year mortality： 62% vs 5%, P 〈 0.001; 1-year recurrence rate： 86% vs 33%, P 〈 0.001）. Patients with score ≥5 had greater possibility of microvascular invasion （P 〈 0.001）, poor tumor dif- ferentiation （P = 0.003）, liver cirrhosis with small nod- ules （P 〈 0.001）, and intraoperative blood transfusion （P = 0.010）. CONCLUSION： A composite preoperative scoring model can be used as an indication of prognosis of HCC patients after surgical resection. Resection should be considered with caution in patients with a score ≥5, which indicates a contraindication for surgery.
文摘Previous studies have shown that children learn from educational television; however, these studies have not explored how closely the educational content of the program is integrated to the narrative. The following study uses a systematic content analysis of 100 top-rated U.S. children＇s television programs to explore the tangential relationship （i.e., distance） of narrative and educational content through the lens of the capacity model--which is built upon three basic components： narrative content, educational content, and the distance between them. Programs were analyzed for distance by examining lesson clarity and integration, show type, target audience age, and station type. One-way ANOVAs indicates significant differences between the means of these variables. Programs targeting younger children presented educational content that was closely integrated into the plotline of the program and helped further the story. However, as the target audience aged, the educational content became more tangential to the narrative content and was less tied to the plotline of the program.
文摘In cutting tool temperature experiment, a large number of related data could be available. In order to define the relationship among the experiment data, the nonlinear regressive curve of cutting tool temperature must be constructed based on the data. This paper proposes the Particle Swarm Optimization (PSO) algorithm for estimating the parameters such a curve. The PSO algorithm is an evolutional method based on a very simple concept. Comparison of PSO results with those of GA and LS methods showed that the PSO algorithm is more effective for estimating the parameters of the above curve.
文摘The identification of Wiener systems has been an active research topic for years. A Wiener system is a series connection of a linear dynamic system followed by a static nonlinearity. The difficulty in obtaining a representation of the Wiener model is the need to estimate the nonlinear function from the input and output data, without the intermediate signal availability. This paper presents a methodology for the nonlinear system identification of a Wiener type model, using methods for subspaces and polynomials of Chebyshev. The subspace methods used are MOESP （multivariable output-error state space） and N4SID （numerical algorithms for subspace state space system identification）. A simulated example is presented to compare the performance of these algorithms.
基金supported by the National Basic Research Program of China(“973”Project)(Grant No.2013CB035603)the National Natural Science Foundation of China(Grant Nos.51177013&51322705)+3 种基金Qing Lan Project of Jiangsu ProvinceSix Talents Climax Project of Jiangsu Province(Grant No.2011-ZBZZ-036)Technology R&D Program of Jiangsu Province(Grant Nos.BE2012100&BY2012195)“333 Talents Project”of Jiangsu Province
文摘In this paper, firstly, a basic nonlinear magnetic network model considering iron saturations is proposed for a three-phase 12-stator-slot/10-rotor-pole flux-switching permanent magnet(FSPM) machine. This model is built under cylindrical coordinates and enables the open-circuit air-gap flux-density distributions, phase permanent magnet(PM) flux-linkage, and electromotive-force(EMF) to be predicted with acceptable accuracy. However, large discrepancies are found in the predictions of armature inductances. Then, the basic model is modified by taking into account the localized saturation effect. As a result, the electromagnetic performance can be predicted more accurately, especially for the air-gap flux-density distributions. Furthermore, two improved models are proposed by adding bypass-bridge branches in stator network, to enhance the calculating accuracy of both saturated and unsaturated armature inductances. Finally, the predicted results from the four magnetic network models are validated by both 2D finite element analysis(FEA) and experimental measurements on a machine prototype. Overall, comparisons indicate that the model with bypass-bridge branches between stator teeth and back irons exhibits best performances.
