A treat-to-target strategy in inflammatory bowel disease(IBD)involves treatment intensification in order to achieve a pre-determined endpoint.Such uniform and tight disease control has been demonstrated to improve cli...A treat-to-target strategy in inflammatory bowel disease(IBD)involves treatment intensification in order to achieve a pre-determined endpoint.Such uniform and tight disease control has been demonstrated to improve clinical outcomes compared to treatment driven by a clinician’s subjective assessment of symptoms.However,choice of treatment endpoints remains a challenge in management of IBD via a treat-to-target strategy.The treatment endpoints for ulcerative colitis(UC),recommended by the Selecting Therapeutic Targets in Inflammatory Bowel Disease(STRIDE)consensus have changed somewhat over time.The latest STRIDE-II consensus advises immediate(clinical response),intermediate(clinical remission and biochemical normalisation)and long-term treatment(endoscopic healing,absence of disability and normalisation of health-related quality of life,as well as normal growth in children)endpoints in UC.However,achieving deeper levels of remission,such as histologic normalisation or healing of the gut barrier function,may further improve outcomes among UC patients.Generally,all medical therapy should seek to improve short-and long-term mortality and morbidity.Hence treatment endpoints should be chosen based on their ability to predict for improvement in short-and long-term mortality and morbidity.Potential benefits of treatment intensification need to be weighed against the potential harms within an individual patient.In addition,changing therapy that has achieved partial response may lead to worse outcomes,with failure to recapture response on treatment reversion.Patients may also place different emphasis on certain potential benefits and harms of various treatments than clinicians,or may have strong opinions re certain therapies.Potential benefits and harms of therapies,incremental benefits of achieving deeper levels of remission,as well as uncertainties of the same,need to be discussed with individual patients,and a treatment endpoint agreed upon with the clinician.Future research should focus on quantifying the incremental benefits and risks of achieving deeper levels of remission,such that clinicians and patients can make an informed decision about appropriate treatment end-point on an individual basis.focus on quantifying the incremental benefits and risks of achieving deeper levels of remission,such that clinicians and patients can make an informed decision about appropriate treatment end-point on an individual basis.展开更多
Two commonly used methods for calculating 50% endpoint using serial dilutions are Spearman-Karber method and Reed and Muench method. To understand/apply the above formulas, moderate statistical/mathematical skills are...Two commonly used methods for calculating 50% endpoint using serial dilutions are Spearman-Karber method and Reed and Muench method. To understand/apply the above formulas, moderate statistical/mathematical skills are necessary. In this paper, a simple formula/method for calculating 50% endpoints has been proposed. The formula yields essentially similar results as those of the SpearmanKarber method. The formula has been rigorously evaluated with several samples.展开更多
A novel yet simple, rapid and robust thermometric endpoint titration (TET) method for the determination of sodium in various foodstuffs is described. Sodium reacts exothermically with aluminium in the presence of an e...A novel yet simple, rapid and robust thermometric endpoint titration (TET) method for the determination of sodium in various foodstuffs is described. Sodium reacts exothermically with aluminium in the presence of an excess of potassium and fluoride ions to form NaK2AlF6 (“elpasolite”). This reaction forms the basis of a ro- bust, reliable analytical procedure suitable for routine process control. The reaction of calcium under similar conditions (to form KCaAlF6) suggests that potentially, calcium may interfere in the determination of sodium in some foodstuffs. Results of an investigation suggest that at molar ratios [Ca]/[Na] < 0.85, an error of <1% of the measured value of sodium is incurred.展开更多
In order to deal with the non-stationary characteristics of blasting vibration signals and the end issue in the empirical mode decomposition(EMD), an improved endpoint continuation method is proposed. First, the linea...In order to deal with the non-stationary characteristics of blasting vibration signals and the end issue in the empirical mode decomposition(EMD), an improved endpoint continuation method is proposed. First, the linear continuation method of extreme points is used to determine the extremum of the signal endpoint fast. Secondly, the extreme points of transition section outside the signal ends are obtained by a mirror continuation method of extreme points, and then the envelope and continuation curve of the transition section of the signal are constructed. Lastly, the sinusoid of the stationary section outside the signal is constructed to achieve the continuation curve from the transition section to the stationary section. Based on the "singular extreme points" phenomenon of blasting vibration signal, the negative maxima and positive minimum are eliminated, then the maximum and minimum are guaranteed to appear at intervals. Thus,the number of iterations is reduced and the instability of EMD decomposition is improved. The calculation formula of amplitude, cycle and initial phase are given for the transition section and stationary section outside the signal. The endpoint processing effect of the simulated signal and the measured blasting vibration signal show that the improved endpoint continuation method can suppress the signal endpoint effect well.展开更多
In clinical trials, the primary efficacy endpoint often corresponds to a so-called "composite endpoint". Composite endpoints combine several events of interest within a single outcome variable. Thereby it is...In clinical trials, the primary efficacy endpoint often corresponds to a so-called "composite endpoint". Composite endpoints combine several events of interest within a single outcome variable. Thereby it is intended to enlarge the expected effect size and thereby increase the power of the study. However, composite endpoints also come along with serious challenges and problems. On the one hand, composite endpoints may lead to difficulties during the planning phase of a trial with respect to the sample size calculation, asthe expected clinical effect of an intervention on the composite endpoint depends on the effects on its single components and their correlations. This may lead to wrong assumptions on the sample size needed. Too optimistic assumptions on the expected effect may lead to an underpowered of the trial, whereas a too conservatively estimated effect results in an unnecessarily high sample size. On the other hand, the interpretation of composite endpoints may be difficult, as the observed effect of the composite does not necessarily reflect the effects of the single components. Therefore the demonstration of the clinical efficacy of a new intervention by exclusively evaluating the composite endpoint may be misleading. The present paper summarizes results and recommendations of the latest research addressing the above mentioned problems in the planning, analysis and interpretation of clinical trials with composite endpoints, thereby providing a practical guidance for users.展开更多
In this paper, for the delay control system:with State right endpoint restricled by conditiona maximum principle is given. And as a specificexample. this paper gives a maximumprinciple under the condition that partial...In this paper, for the delay control system:with State right endpoint restricled by conditiona maximum principle is given. And as a specificexample. this paper gives a maximumprinciple under the condition that partial states right endpoints be completely fixed.Finally , this paper gives an example to explain the application of the main result ofthis paper. All the results are suitable for the control systems with multidelay as well.展开更多
In this paper we consider operators with endpoint singularities generated by linear fractional Carleman shift in weighted Hölder spaces. Such operators play an important role in the study of algebras generate...In this paper we consider operators with endpoint singularities generated by linear fractional Carleman shift in weighted Hölder spaces. Such operators play an important role in the study of algebras generated by the operators of singular integration and multiplication by function. For the considered operators, we obtained more precise relations between norms of integral operators with local singularities in weighted Lebesgue spaces and norms in weighted Hölder spaces, making use of previously obtained general results. We prove the boundedness of operators with linear fractional singularities.展开更多
Due to ethical and logistical concerns it is common for data monitoring committees to periodically monitor accruing clinical trial data to assess the safety, and possibly efficacy, of a new experimental treatment. Whe...Due to ethical and logistical concerns it is common for data monitoring committees to periodically monitor accruing clinical trial data to assess the safety, and possibly efficacy, of a new experimental treatment. When formalized, monitoring is typically implemented using group sequential methods. In some cases regulatory agencies have required that primary trial analyses should be based solely on the judgment of an independent review committee (IRC). The IRC assessments can produce difficulties for trial monitoring given the time lag typically associated with receiving assessments from the IRC. This results in a missing data problem wherein a surrogate measure of response may provide useful information for interim decisions and future monitoring strategies. In this paper, we present statistical tools that are helpful for monitoring a group sequential clinical trial with missing IRC data. We illustrate the proposed methodology in the case of binary endpoints under various missingness mechanisms including missing completely at random assessments and when missingness depends on the IRC’s measurement.展开更多
Objective: To create a multidimensional composite outcomes endpoint for gouty arthritis treatment in order to consolidate disparate measures of comparative effectiveness. Methods: One solution is to create a multidime...Objective: To create a multidimensional composite outcomes endpoint for gouty arthritis treatment in order to consolidate disparate measures of comparative effectiveness. Methods: One solution is to create a multidimensional composite endpoint that consolidates the complexity of outcomes into a single scale, as was done in this study. The psychometrics of the multidimensional scale and subgroup differences were investigated. Results: Cronbach’s alpha for the multidimensional composite endpoint created in this study was 0.76, indicating good internal reliability. Similar results were found across age, race, and gender. Removing any single item did not increase Cronbach’s alpha beyond 0.77, indicating that none of the items were interfering with the reliability of the scale. However, a reduction in serum urate levels was not significantly correlated with the overall multidimensional endpoint scale with that variable removed, r = 0.03, p > 0.05. Conclusion: This study demonstrated the feasibility and usefulness of creating a composite multidimensional endpoint for assessing treatment outcomes among individuals with gouty arthritis.展开更多
As the Web of Data grows, the number of available SPARQL endpoints increases. SPARQL endpoints conceptually represent RPC-style, coarse-grained data access mechanisms. Nevertheless, through the potential interlinking ...As the Web of Data grows, the number of available SPARQL endpoints increases. SPARQL endpoints conceptually represent RPC-style, coarse-grained data access mechanisms. Nevertheless, through the potential interlinking of the contained entities, SPARQL endpoints should be able to over distinct advantages over plain Web APIs. To our knowledge, to date, there has been no study conducted that gauges the impact of the link on SPARQL query execution, especially in a federated set-up. In this paper, we investigate how the existence and types of typed links influences the execution characteristics of different SPARQL federation frameworks. In order to measure the query performance, we propose a combined cost model based on a statistic analysis of the query performance metrics that involves parameters such as type of link, the data catalogues and cache, number of links, and number of distinct subjects. As result, we show that number of distinct subject and number of links have significant impact on Federation over SPARQL Endpoints performance whereas type of link does not have significantly influence in federation query performance.展开更多
The present work considers the endpoint in the abstract metric space. It firstly introduces the metric space of partially ordered groups and the metric space of partially ordered modules, respectively;and defines the ...The present work considers the endpoint in the abstract metric space. It firstly introduces the metric space of partially ordered groups and the metric space of partially ordered modules, respectively;and defines the convergence of sequences and the multi-valued weak contractions, etc., on the introduced space. And then, with the methods of functional analysis and abstract algebra, it successively establishes an endpoint theorem for the metric space of partially ordered groups and an endpoint theorem for the metric space of partially ordered modules. The contributions of this article extend the theory of cone metric space constructed by Huang and Zhang (2007) and some recent results on the fixed point and endpoint theory, such as the endpoint theorem given by Amini-Harandi (2010).展开更多
Objectives To explore the optimization method of vaccine clinical trial design based on immunological surrogate endpoint to improve the quality and efficiency of vaccine clinical research and development.Methods As to...Objectives To explore the optimization method of vaccine clinical trial design based on immunological surrogate endpoint to improve the quality and efficiency of vaccine clinical research and development.Methods As to the problems in the vaccine clinical research in China,the relevant guidelines and literatures of FDA and WHO were used to analyze and summarize the methods of optimizing the design of vaccine clinical trials.Results and Conclusion The adaptive design guidelines are established to guide clinical trial design,encourage the development and application of immunological surrogate endpoints,establish qualification process for drug development tools and information disclosure procedures to improve vaccine development efficiency.展开更多
Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and th...Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and then fix any geometric errors correspondingly. However, the traditional tube inspection method is time-consuming and complex operations. Therefore, a new measurement method for a tube's endpoints based on machine vision is proposed. First, reflected light on tube's surface can be removed by using photometric linearization. Then, based on the optimization model for the tube's endpoint measurements and the principle of stereo matching, the global coordinates and the relative distance of the tube's endpoint are obtained. To confirm the feasibility, 11 tubes are processed to remove the reflected light and then the endpoint's positions of tubes are measured. The experiment results show that the measurement repeatability accuracy is 0.167 mm, and the absolute accuracy is 0.328 mm. The measurement takes less than 1 min. The proposed method based on machine vision can measure the tube's endpoints without any surface treatment or any tools and can realize on line measurement.展开更多
Numerical simulation has been carried out to investigate the major factors affecting the time of composite regeneration due to coupling cerium-based additive and microwave for diesel particulate f3ilter(DPF). Effect o...Numerical simulation has been carried out to investigate the major factors affecting the time of composite regeneration due to coupling cerium-based additive and microwave for diesel particulate f3ilter(DPF). Effect on the composite regeneration time from various factors such as mass flow rate of exhaust gas, temperature of exhaust gas, oxygen concentration of exhaust gas, microwave power and amount of cerium-based additive are investigated. And a mathematical model based on fuzzy least squares support vector machines has been developed to forecast the endpoint of the composite regeneration. The results show that the relative error of endpoint forecasting model of composite regeneration is less than 3.5%, and the oxygen concentration of exhaust gas has the biggest effect on the endpoint of composite regeneration, followed by the mass flow rate of exhaust gas, the microwave power, the temperature of exhaust gas and the amount of cerium-based additive.展开更多
The endpoint parameters are very important to the process of EAF steel-making, but their on-line measurement is difficult. The soft sensor technology is widely used for the prediction of endpoint parameters. Based on ...The endpoint parameters are very important to the process of EAF steel-making, but their on-line measurement is difficult. The soft sensor technology is widely used for the prediction of endpoint parameters. Based on the analysis of the smelting process of EAF and the advantages of support vector machines, a soft sensor model for predicting the endpoint parameters was built using multiple support vector machines (MSVM). In this model, the input space was divided by subtractive clustering and a sub-model based on LS-SVM was built in each sub-space. To decrease the correlation among the sub-models and to improve the accuracy and robustness of the model, the sub-models were combined by Principal Components Regression. The accuracy of the soft sensor model is perfectly improved. The simulation result demonstrates the practicability and efficiency of the MSVM model for the endpoint prediction of EAF.展开更多
Accurate endpoint detection is a necessary capability for speech recognition. A new energy measure method based on the empirical mode decomposition (EMD) algorithm and Teager energy operator (TEO) is proposed to locat...Accurate endpoint detection is a necessary capability for speech recognition. A new energy measure method based on the empirical mode decomposition (EMD) algorithm and Teager energy operator (TEO) is proposed to locate endpoint intervals of a speech signal embedded in noise. With the EMD, the noise signals can be decomposed into different numbers of sub-signals called intrinsic mode functions (IMFs), which is a zero-mean AM-FM component. Then TEO can be used to extract the desired feature of the modulation energy for IMF components. In order to show the effectiveness of the proposed method, examples are presented to show that the new measure is more effective than traditional measures. The present experimental results show that the measure can be used to improve the performance of endpoint detection algorithms and the accuracy of this algorithm is quite satisfactory and acceptable.展开更多
An adaptive endpoint detection algorithm based on band energy and adaptive smoothing algorithm is described.This algorithm utilizes the capability of adaptive smoothing algorithm that intensifies the discontinuity bet...An adaptive endpoint detection algorithm based on band energy and adaptive smoothing algorithm is described.This algorithm utilizes the capability of adaptive smoothing algorithm that intensifies the discontinuity between local areas. The band energy features are selected because of their usefulness in detecting high energy regions (in the incoming signal) and making the distinction between speech and noise. Heuristic "edge-focusing" is used to endpoint detection to save the time in iteration.展开更多
文摘A treat-to-target strategy in inflammatory bowel disease(IBD)involves treatment intensification in order to achieve a pre-determined endpoint.Such uniform and tight disease control has been demonstrated to improve clinical outcomes compared to treatment driven by a clinician’s subjective assessment of symptoms.However,choice of treatment endpoints remains a challenge in management of IBD via a treat-to-target strategy.The treatment endpoints for ulcerative colitis(UC),recommended by the Selecting Therapeutic Targets in Inflammatory Bowel Disease(STRIDE)consensus have changed somewhat over time.The latest STRIDE-II consensus advises immediate(clinical response),intermediate(clinical remission and biochemical normalisation)and long-term treatment(endoscopic healing,absence of disability and normalisation of health-related quality of life,as well as normal growth in children)endpoints in UC.However,achieving deeper levels of remission,such as histologic normalisation or healing of the gut barrier function,may further improve outcomes among UC patients.Generally,all medical therapy should seek to improve short-and long-term mortality and morbidity.Hence treatment endpoints should be chosen based on their ability to predict for improvement in short-and long-term mortality and morbidity.Potential benefits of treatment intensification need to be weighed against the potential harms within an individual patient.In addition,changing therapy that has achieved partial response may lead to worse outcomes,with failure to recapture response on treatment reversion.Patients may also place different emphasis on certain potential benefits and harms of various treatments than clinicians,or may have strong opinions re certain therapies.Potential benefits and harms of therapies,incremental benefits of achieving deeper levels of remission,as well as uncertainties of the same,need to be discussed with individual patients,and a treatment endpoint agreed upon with the clinician.Future research should focus on quantifying the incremental benefits and risks of achieving deeper levels of remission,such that clinicians and patients can make an informed decision about appropriate treatment end-point on an individual basis.focus on quantifying the incremental benefits and risks of achieving deeper levels of remission,such that clinicians and patients can make an informed decision about appropriate treatment end-point on an individual basis.
文摘Two commonly used methods for calculating 50% endpoint using serial dilutions are Spearman-Karber method and Reed and Muench method. To understand/apply the above formulas, moderate statistical/mathematical skills are necessary. In this paper, a simple formula/method for calculating 50% endpoints has been proposed. The formula yields essentially similar results as those of the SpearmanKarber method. The formula has been rigorously evaluated with several samples.
文摘A novel yet simple, rapid and robust thermometric endpoint titration (TET) method for the determination of sodium in various foodstuffs is described. Sodium reacts exothermically with aluminium in the presence of an excess of potassium and fluoride ions to form NaK2AlF6 (“elpasolite”). This reaction forms the basis of a ro- bust, reliable analytical procedure suitable for routine process control. The reaction of calcium under similar conditions (to form KCaAlF6) suggests that potentially, calcium may interfere in the determination of sodium in some foodstuffs. Results of an investigation suggest that at molar ratios [Ca]/[Na] < 0.85, an error of <1% of the measured value of sodium is incurred.
基金Supported by the National Natural Science Foundation of China(51374212)
文摘In order to deal with the non-stationary characteristics of blasting vibration signals and the end issue in the empirical mode decomposition(EMD), an improved endpoint continuation method is proposed. First, the linear continuation method of extreme points is used to determine the extremum of the signal endpoint fast. Secondly, the extreme points of transition section outside the signal ends are obtained by a mirror continuation method of extreme points, and then the envelope and continuation curve of the transition section of the signal are constructed. Lastly, the sinusoid of the stationary section outside the signal is constructed to achieve the continuation curve from the transition section to the stationary section. Based on the "singular extreme points" phenomenon of blasting vibration signal, the negative maxima and positive minimum are eliminated, then the maximum and minimum are guaranteed to appear at intervals. Thus,the number of iterations is reduced and the instability of EMD decomposition is improved. The calculation formula of amplitude, cycle and initial phase are given for the transition section and stationary section outside the signal. The endpoint processing effect of the simulated signal and the measured blasting vibration signal show that the improved endpoint continuation method can suppress the signal endpoint effect well.
文摘In clinical trials, the primary efficacy endpoint often corresponds to a so-called "composite endpoint". Composite endpoints combine several events of interest within a single outcome variable. Thereby it is intended to enlarge the expected effect size and thereby increase the power of the study. However, composite endpoints also come along with serious challenges and problems. On the one hand, composite endpoints may lead to difficulties during the planning phase of a trial with respect to the sample size calculation, asthe expected clinical effect of an intervention on the composite endpoint depends on the effects on its single components and their correlations. This may lead to wrong assumptions on the sample size needed. Too optimistic assumptions on the expected effect may lead to an underpowered of the trial, whereas a too conservatively estimated effect results in an unnecessarily high sample size. On the other hand, the interpretation of composite endpoints may be difficult, as the observed effect of the composite does not necessarily reflect the effects of the single components. Therefore the demonstration of the clinical efficacy of a new intervention by exclusively evaluating the composite endpoint may be misleading. The present paper summarizes results and recommendations of the latest research addressing the above mentioned problems in the planning, analysis and interpretation of clinical trials with composite endpoints, thereby providing a practical guidance for users.
文摘In this paper, for the delay control system:with State right endpoint restricled by conditiona maximum principle is given. And as a specificexample. this paper gives a maximumprinciple under the condition that partial states right endpoints be completely fixed.Finally , this paper gives an example to explain the application of the main result ofthis paper. All the results are suitable for the control systems with multidelay as well.
文摘In this paper we consider operators with endpoint singularities generated by linear fractional Carleman shift in weighted Hölder spaces. Such operators play an important role in the study of algebras generated by the operators of singular integration and multiplication by function. For the considered operators, we obtained more precise relations between norms of integral operators with local singularities in weighted Lebesgue spaces and norms in weighted Hölder spaces, making use of previously obtained general results. We prove the boundedness of operators with linear fractional singularities.
文摘Due to ethical and logistical concerns it is common for data monitoring committees to periodically monitor accruing clinical trial data to assess the safety, and possibly efficacy, of a new experimental treatment. When formalized, monitoring is typically implemented using group sequential methods. In some cases regulatory agencies have required that primary trial analyses should be based solely on the judgment of an independent review committee (IRC). The IRC assessments can produce difficulties for trial monitoring given the time lag typically associated with receiving assessments from the IRC. This results in a missing data problem wherein a surrogate measure of response may provide useful information for interim decisions and future monitoring strategies. In this paper, we present statistical tools that are helpful for monitoring a group sequential clinical trial with missing IRC data. We illustrate the proposed methodology in the case of binary endpoints under various missingness mechanisms including missing completely at random assessments and when missingness depends on the IRC’s measurement.
文摘Objective: To create a multidimensional composite outcomes endpoint for gouty arthritis treatment in order to consolidate disparate measures of comparative effectiveness. Methods: One solution is to create a multidimensional composite endpoint that consolidates the complexity of outcomes into a single scale, as was done in this study. The psychometrics of the multidimensional scale and subgroup differences were investigated. Results: Cronbach’s alpha for the multidimensional composite endpoint created in this study was 0.76, indicating good internal reliability. Similar results were found across age, race, and gender. Removing any single item did not increase Cronbach’s alpha beyond 0.77, indicating that none of the items were interfering with the reliability of the scale. However, a reduction in serum urate levels was not significantly correlated with the overall multidimensional endpoint scale with that variable removed, r = 0.03, p > 0.05. Conclusion: This study demonstrated the feasibility and usefulness of creating a composite multidimensional endpoint for assessing treatment outcomes among individuals with gouty arthritis.
文摘As the Web of Data grows, the number of available SPARQL endpoints increases. SPARQL endpoints conceptually represent RPC-style, coarse-grained data access mechanisms. Nevertheless, through the potential interlinking of the contained entities, SPARQL endpoints should be able to over distinct advantages over plain Web APIs. To our knowledge, to date, there has been no study conducted that gauges the impact of the link on SPARQL query execution, especially in a federated set-up. In this paper, we investigate how the existence and types of typed links influences the execution characteristics of different SPARQL federation frameworks. In order to measure the query performance, we propose a combined cost model based on a statistic analysis of the query performance metrics that involves parameters such as type of link, the data catalogues and cache, number of links, and number of distinct subjects. As result, we show that number of distinct subject and number of links have significant impact on Federation over SPARQL Endpoints performance whereas type of link does not have significantly influence in federation query performance.
文摘The present work considers the endpoint in the abstract metric space. It firstly introduces the metric space of partially ordered groups and the metric space of partially ordered modules, respectively;and defines the convergence of sequences and the multi-valued weak contractions, etc., on the introduced space. And then, with the methods of functional analysis and abstract algebra, it successively establishes an endpoint theorem for the metric space of partially ordered groups and an endpoint theorem for the metric space of partially ordered modules. The contributions of this article extend the theory of cone metric space constructed by Huang and Zhang (2007) and some recent results on the fixed point and endpoint theory, such as the endpoint theorem given by Amini-Harandi (2010).
文摘Objectives To explore the optimization method of vaccine clinical trial design based on immunological surrogate endpoint to improve the quality and efficiency of vaccine clinical research and development.Methods As to the problems in the vaccine clinical research in China,the relevant guidelines and literatures of FDA and WHO were used to analyze and summarize the methods of optimizing the design of vaccine clinical trials.Results and Conclusion The adaptive design guidelines are established to guide clinical trial design,encourage the development and application of immunological surrogate endpoints,establish qualification process for drug development tools and information disclosure procedures to improve vaccine development efficiency.
基金Supported by National Natural Science Foundation of China(Grant No51305031)
文摘Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and then fix any geometric errors correspondingly. However, the traditional tube inspection method is time-consuming and complex operations. Therefore, a new measurement method for a tube's endpoints based on machine vision is proposed. First, reflected light on tube's surface can be removed by using photometric linearization. Then, based on the optimization model for the tube's endpoint measurements and the principle of stereo matching, the global coordinates and the relative distance of the tube's endpoint are obtained. To confirm the feasibility, 11 tubes are processed to remove the reflected light and then the endpoint's positions of tubes are measured. The experiment results show that the measurement repeatability accuracy is 0.167 mm, and the absolute accuracy is 0.328 mm. The measurement takes less than 1 min. The proposed method based on machine vision can measure the tube's endpoints without any surface treatment or any tools and can realize on line measurement.
基金Projects(51176045,51276056)supported by the National Natural Science Foundation of ChinaProject(201208430262)supported by the National Studying Abroad Foundation Project of China
文摘Numerical simulation has been carried out to investigate the major factors affecting the time of composite regeneration due to coupling cerium-based additive and microwave for diesel particulate f3ilter(DPF). Effect on the composite regeneration time from various factors such as mass flow rate of exhaust gas, temperature of exhaust gas, oxygen concentration of exhaust gas, microwave power and amount of cerium-based additive are investigated. And a mathematical model based on fuzzy least squares support vector machines has been developed to forecast the endpoint of the composite regeneration. The results show that the relative error of endpoint forecasting model of composite regeneration is less than 3.5%, and the oxygen concentration of exhaust gas has the biggest effect on the endpoint of composite regeneration, followed by the mass flow rate of exhaust gas, the microwave power, the temperature of exhaust gas and the amount of cerium-based additive.
基金Item Sponsored by National Natural Science Foundation of China (60374003)
文摘The endpoint parameters are very important to the process of EAF steel-making, but their on-line measurement is difficult. The soft sensor technology is widely used for the prediction of endpoint parameters. Based on the analysis of the smelting process of EAF and the advantages of support vector machines, a soft sensor model for predicting the endpoint parameters was built using multiple support vector machines (MSVM). In this model, the input space was divided by subtractive clustering and a sub-model based on LS-SVM was built in each sub-space. To decrease the correlation among the sub-models and to improve the accuracy and robustness of the model, the sub-models were combined by Principal Components Regression. The accuracy of the soft sensor model is perfectly improved. The simulation result demonstrates the practicability and efficiency of the MSVM model for the endpoint prediction of EAF.
基金supported by the National Natural Science Foundation of China under Grant No. 60771033
文摘Accurate endpoint detection is a necessary capability for speech recognition. A new energy measure method based on the empirical mode decomposition (EMD) algorithm and Teager energy operator (TEO) is proposed to locate endpoint intervals of a speech signal embedded in noise. With the EMD, the noise signals can be decomposed into different numbers of sub-signals called intrinsic mode functions (IMFs), which is a zero-mean AM-FM component. Then TEO can be used to extract the desired feature of the modulation energy for IMF components. In order to show the effectiveness of the proposed method, examples are presented to show that the new measure is more effective than traditional measures. The present experimental results show that the measure can be used to improve the performance of endpoint detection algorithms and the accuracy of this algorithm is quite satisfactory and acceptable.
文摘An adaptive endpoint detection algorithm based on band energy and adaptive smoothing algorithm is described.This algorithm utilizes the capability of adaptive smoothing algorithm that intensifies the discontinuity between local areas. The band energy features are selected because of their usefulness in detecting high energy regions (in the incoming signal) and making the distinction between speech and noise. Heuristic "edge-focusing" is used to endpoint detection to save the time in iteration.
