This paper is devoted to the goodness-of-fit test for the general autoregressive models in time series. By averaging for the weighted residuals, we construct a score type test which is asymptotically standard chi-squa...This paper is devoted to the goodness-of-fit test for the general autoregressive models in time series. By averaging for the weighted residuals, we construct a score type test which is asymptotically standard chi-squared under the null and has some desirable power properties under the alternatives. Specifically, the test is sensitive to alternatives and can detect the alternatives approaching, along a direction, the null at a rate that is arbitrarily close to n-1/2. Furthermore, when the alternatives are not directional, we construct asymptotically distribution-free maximin tests for a large class of alternatives. The performance of the tests is evaluated through simulation studies.展开更多
In this article a new approach for checking the adequacy of GARCH-type models in time series was proposed. The resulted tests involve weight functions, which provide them with the flexibility in choosing scores to enh...In this article a new approach for checking the adequacy of GARCH-type models in time series was proposed. The resulted tests involve weight functions, which provide them with the flexibility in choosing scores to enhance power performance. The choice of weight functions and the power properties of the tests are studied. For a large number of alternatives, asymptotically distribution-free maximin test is constructed. The tests are asymptotically chi-squared under the null hypothesis and easy to implement. Simulation results indicate that the tests perform well.展开更多
The empirical upper percentage points of the null distribution of a Kolmogorov-Smirnov type test for checking linearity in autoregressive models are tabulated in this paper, and the good power property of the test is ...The empirical upper percentage points of the null distribution of a Kolmogorov-Smirnov type test for checking linearity in autoregressive models are tabulated in this paper, and the good power property of the test is demonstrated.展开更多
A family of integral-type goodness-of-fit tests is investigated.This family includes someexisting tests,such as the Cramér-von Mises test and Anderson-Darling test,etc.The asymptoticdistributions of the tests in ...A family of integral-type goodness-of-fit tests is investigated.This family includes someexisting tests,such as the Cramér-von Mises test and Anderson-Darling test,etc.The asymptoticdistributions of the tests in the family under the null and local alternative hypotheses are established.The almost sure convergence under a fixed underlying distribution is obtained.Furthermore,simulationsare conducted to compare the powers of the tests in the family.Simulation results show that fordifferent alternatives,the more powerful tests are different,and the parameter λ has great influence onthe tests in small sample cases.展开更多
This paper aims to develop a new robust U-type test for high dimensional regression coefficients using the estimated U-statistic of order two and refitted cross-validation error variance estimation. It is proved that ...This paper aims to develop a new robust U-type test for high dimensional regression coefficients using the estimated U-statistic of order two and refitted cross-validation error variance estimation. It is proved that the limiting null distribution of the proposed new test is normal under two kinds of ordinary models.We further study the local power of the proposed test and compare with other competitive tests for high dimensional data. The idea of refitted cross-validation approach is utilized to reduce the bias of sample variance in the estimation of the test statistic. Our theoretical results indicate that the proposed test can have even more substantial power gain than the test by Zhong and Chen(2011) when testing a hypothesis with outlying observations and heavy tailed distributions. We assess the finite-sample performance of the proposed test by examining its size and power via Monte Carlo studies. We also illustrate the application of the proposed test by an empirical analysis of a real data example.展开更多
Multiple endocrine neoplasia type 1(MEN1) is an autosomal dominant inherited tumour syndrome expressing various endocrine and non-endocrine lesions and tumours. Since the identification of the causative gene, the onco...Multiple endocrine neoplasia type 1(MEN1) is an autosomal dominant inherited tumour syndrome expressing various endocrine and non-endocrine lesions and tumours. Since the identification of the causative gene, the oncosuppressor gene MEN1, in 1997, genetic testing has revealed an important approach for the early and differential diagnosis of the disease. The finding of a MEN1 mutation in a patient has important clinical implications for relatives since it allows very early disease diagnosis and identification of carriers, even before biochemical and/or clinical manifestation, permitting their inclusion in a specific program of surveillance and subsequent praecox therapy. Currently, genetic testing for MEN1 consists principally of the sequencing of coding regions and intron-exon junctions of the MEN1 gene. However, the recent acquisition of novel high throughput technologies will allow the design of innovative, accurate, complete and rapid genetic diagnosis. These new tools are able to increase the strength of the analysis and almost completely eliminate the possibility of false negative results. This review aims to give an overview on genetic testing of MEN1 syndrome, reporting the positive aspects of performing the analysis and the future perspectives for improving the performance of the test, as well as its application in clinical practice.展开更多
Porcine cimovirus type 2 (PCV2) infection causes huge economic losses, but no serological method is available for batch detection of field samples. The aim of the study was to develop a method for large-batch detectio...Porcine cimovirus type 2 (PCV2) infection causes huge economic losses, but no serological method is available for batch detection of field samples. The aim of the study was to develop a method for large-batch detection of PCV2 infection. Colloidal gold-labeled staphylococcal protein A (SPA) was sprayed on glass fibers to prepare a conjugate pad. The recombinant ORF2 protein of PCV2 was blotted on the test line of the nitrocellulose (NC) membrane, and pig IgG was streaked on the control line of the NC membrane. Then, the immunochromatographic strip was used for detection of antibodies against PCV2. The results show that the strip test was simple and the results could be determined within 10 min with naked eyes. The test strip was highly specific for pig serum against PCV2 and no cross-reaction with pig serum against other pathogens was observed. The test strip had close similarity with ELISA. Storage at RT for 6 months did not affect the specificity and sensitivity obviously. A total of 324 clinical pig sera were detected by both ELISA and the developed test strip, and the coincidence was 98.77%. Therefore, the developed immunochromatographic strip is specific, sensitive, stable, fast and simple, and it is suitable for on-site detection of antibodies against PCV2.展开更多
Background: A secretion of plasma active GLP-1 (p-active GLP-1) after ingestion of breakfast test meal (TM) is decreased in obese European patients with type 2 diabetes mellitus (T2DM). However, there was no significa...Background: A secretion of plasma active GLP-1 (p-active GLP-1) after ingestion of breakfast test meal (TM) is decreased in obese European patients with type 2 diabetes mellitus (T2DM). However, there was no significant difference in pactive GLP-1 secretion following TM between obese Japanese patients with T2DM and controls. The findings indicate the difference may be due to different races or dietary’s customs of subjects. Aims: We examined whether pactive GLP-1 is truly affected by TM in obese Japanese patients (n = 24, group 1) and obese controls (n = 12, group 2). Methods: Glucose (PG), insulin (s-IRI), C-peptide (s-CPR) and active GLP-1 like substances (p-active GLP-1-S) levels in blood were measured 0, 30 and 60 min after TM. Obese Japanese patients with mean 9 years of diabetes had micro- and macro-vascular disturbances and were treated with diet, exercise and/or oral drugs for hyperglycemia. Results: There was no significant difference in sex, age or BMI between groups. Means HbA1c and PG were significantly higher in group 1 than in group 2. There were no significant differences in means of basal s-IRI, HOMA-R and s-CPR between groups. However, means of HOMA-β, insulinogenic index, postprandial s-IRI, s-CPR and p-active GLP-1-S or p-active GLP-1-S/PG values after TM were significantly lower in group 1 than in group 2. Conclusions: These results indicate that a response of p-active GLP-1-S after TM in obese Japanese patients with T2DM was decreased and secretion of GLP-1 relative to PG was impaired. The method of enhancing function of active GLP-1 may be useful for treatment in some of patients with diabetes mellitus.展开更多
When a statistical test of hypothesis for a population mean is performed, we are faced with the possibility of committing a Type II error by not rejecting the null hypothesis when in fact the population mean has chang...When a statistical test of hypothesis for a population mean is performed, we are faced with the possibility of committing a Type II error by not rejecting the null hypothesis when in fact the population mean has changed. We consider this issue and quantify matters in a manner that differs a bit from what is commonly done. In particular, we define the probability distribution function for Type II errors. We then explore some interesting properties that we have not seen mentioned elsewhere for this probability distribution function. Finally, we discuss several Maple procedures that can be used to perform various calculations using the distribution.展开更多
This paper proposes a simple constant-stress accel- erated life test (ALT) model from Burr type XII distribution when the data are Type-I progressively hybrid censored. The maximum likelihood estimation (MLE) of t...This paper proposes a simple constant-stress accel- erated life test (ALT) model from Burr type XII distribution when the data are Type-I progressively hybrid censored. The maximum likelihood estimation (MLE) of the parameters is obtained through the numerical method for solving the likelihood equations. Approxi- mate confidence interval (CI), based on normal approximation to the asymptotic distribution of MLE and percentile bootstrap Cl is derived. Finally, a numerical example is introduced and then a Monte Carlo simulation study is carried out to illustrate the pro- posed method.展开更多
换相失败问题(commutation failure,CF)是电网换相换流高压直流输电技术(line commutated converter high voltage directcurrent,LCC-HVDC)面临的固有难题。为了解决该问题,已有文献主要从拓扑结构、控制策略等方面着手,鲜见抵御换相...换相失败问题(commutation failure,CF)是电网换相换流高压直流输电技术(line commutated converter high voltage directcurrent,LCC-HVDC)面临的固有难题。为了解决该问题,已有文献主要从拓扑结构、控制策略等方面着手,鲜见抵御换相失败的新型换流阀研制及试验研究。该文开展基于大功率逆阻型集成门极换流晶闸管(reverse blocking integrated gate commutated thyristor,RB-IGCT)的新型换流阀试验研究及试验等效性分析。首先,阐释新型换流阀抵御换相失败的原理,并针对新型换流阀不同的工作模式,提出对新型电力电子器件的需求。然后,利用现有的型式试验合成回路平台开展适用于传统晶闸管换流阀的运行试验,并分析试验结果,得出大部分试验项目等效性较好而小熄弧角试验和关断试验等效性较差的结论。最后,针对这两项特殊试验提出新的试验方法和试验电路,可为新型换流阀的研发和应用提供一定的技术基础。展开更多
基金grant from the Research Grants Council of Hong Kong
文摘This paper is devoted to the goodness-of-fit test for the general autoregressive models in time series. By averaging for the weighted residuals, we construct a score type test which is asymptotically standard chi-squared under the null and has some desirable power properties under the alternatives. Specifically, the test is sensitive to alternatives and can detect the alternatives approaching, along a direction, the null at a rate that is arbitrarily close to n-1/2. Furthermore, when the alternatives are not directional, we construct asymptotically distribution-free maximin tests for a large class of alternatives. The performance of the tests is evaluated through simulation studies.
基金supported by a grant from the Research Grants Council of Hong Kong.Jianhong Wu was also supported by a grant from Humanities & Social Sciences in Chinese University (07JJD790154)the Youth Talent Foundation of Zhejiang GongShang University (Q09-12)
文摘In this article a new approach for checking the adequacy of GARCH-type models in time series was proposed. The resulted tests involve weight functions, which provide them with the flexibility in choosing scores to enhance power performance. The choice of weight functions and the power properties of the tests are studied. For a large number of alternatives, asymptotically distribution-free maximin test is constructed. The tests are asymptotically chi-squared under the null hypothesis and easy to implement. Simulation results indicate that the tests perform well.
基金a Grant from the Natural Sciences and Engineering Research Council of Canada. This research is supported in part by the Nation
文摘The empirical upper percentage points of the null distribution of a Kolmogorov-Smirnov type test for checking linearity in autoregressive models are tabulated in this paper, and the good power property of the test is demonstrated.
基金supported by the National Natural Science Foundation of China under Grant Nos. 10661003, 10371126the Guangxi Science Foundation under Grant No. 0832102the Doctor Foundation of Guangxi Normal University
文摘A family of integral-type goodness-of-fit tests is investigated.This family includes someexisting tests,such as the Cramér-von Mises test and Anderson-Darling test,etc.The asymptoticdistributions of the tests in the family under the null and local alternative hypotheses are established.The almost sure convergence under a fixed underlying distribution is obtained.Furthermore,simulationsare conducted to compare the powers of the tests in the family.Simulation results show that fordifferent alternatives,the more powerful tests are different,and the parameter λ has great influence onthe tests in small sample cases.
基金supported by National Natural Science Foundation of China (Grant Nos. 11071022, 11231010 and 11471223)Beijing Center for Mathematics and Information Interdisciplinary ScienceKey Project of Beijing Municipal Educational Commission (Grant No. KZ201410028030)
文摘This paper aims to develop a new robust U-type test for high dimensional regression coefficients using the estimated U-statistic of order two and refitted cross-validation error variance estimation. It is proved that the limiting null distribution of the proposed new test is normal under two kinds of ordinary models.We further study the local power of the proposed test and compare with other competitive tests for high dimensional data. The idea of refitted cross-validation approach is utilized to reduce the bias of sample variance in the estimation of the test statistic. Our theoretical results indicate that the proposed test can have even more substantial power gain than the test by Zhong and Chen(2011) when testing a hypothesis with outlying observations and heavy tailed distributions. We assess the finite-sample performance of the proposed test by examining its size and power via Monte Carlo studies. We also illustrate the application of the proposed test by an empirical analysis of a real data example.
文摘Multiple endocrine neoplasia type 1(MEN1) is an autosomal dominant inherited tumour syndrome expressing various endocrine and non-endocrine lesions and tumours. Since the identification of the causative gene, the oncosuppressor gene MEN1, in 1997, genetic testing has revealed an important approach for the early and differential diagnosis of the disease. The finding of a MEN1 mutation in a patient has important clinical implications for relatives since it allows very early disease diagnosis and identification of carriers, even before biochemical and/or clinical manifestation, permitting their inclusion in a specific program of surveillance and subsequent praecox therapy. Currently, genetic testing for MEN1 consists principally of the sequencing of coding regions and intron-exon junctions of the MEN1 gene. However, the recent acquisition of novel high throughput technologies will allow the design of innovative, accurate, complete and rapid genetic diagnosis. These new tools are able to increase the strength of the analysis and almost completely eliminate the possibility of false negative results. This review aims to give an overview on genetic testing of MEN1 syndrome, reporting the positive aspects of performing the analysis and the future perspectives for improving the performance of the test, as well as its application in clinical practice.
文摘Porcine cimovirus type 2 (PCV2) infection causes huge economic losses, but no serological method is available for batch detection of field samples. The aim of the study was to develop a method for large-batch detection of PCV2 infection. Colloidal gold-labeled staphylococcal protein A (SPA) was sprayed on glass fibers to prepare a conjugate pad. The recombinant ORF2 protein of PCV2 was blotted on the test line of the nitrocellulose (NC) membrane, and pig IgG was streaked on the control line of the NC membrane. Then, the immunochromatographic strip was used for detection of antibodies against PCV2. The results show that the strip test was simple and the results could be determined within 10 min with naked eyes. The test strip was highly specific for pig serum against PCV2 and no cross-reaction with pig serum against other pathogens was observed. The test strip had close similarity with ELISA. Storage at RT for 6 months did not affect the specificity and sensitivity obviously. A total of 324 clinical pig sera were detected by both ELISA and the developed test strip, and the coincidence was 98.77%. Therefore, the developed immunochromatographic strip is specific, sensitive, stable, fast and simple, and it is suitable for on-site detection of antibodies against PCV2.
文摘Background: A secretion of plasma active GLP-1 (p-active GLP-1) after ingestion of breakfast test meal (TM) is decreased in obese European patients with type 2 diabetes mellitus (T2DM). However, there was no significant difference in pactive GLP-1 secretion following TM between obese Japanese patients with T2DM and controls. The findings indicate the difference may be due to different races or dietary’s customs of subjects. Aims: We examined whether pactive GLP-1 is truly affected by TM in obese Japanese patients (n = 24, group 1) and obese controls (n = 12, group 2). Methods: Glucose (PG), insulin (s-IRI), C-peptide (s-CPR) and active GLP-1 like substances (p-active GLP-1-S) levels in blood were measured 0, 30 and 60 min after TM. Obese Japanese patients with mean 9 years of diabetes had micro- and macro-vascular disturbances and were treated with diet, exercise and/or oral drugs for hyperglycemia. Results: There was no significant difference in sex, age or BMI between groups. Means HbA1c and PG were significantly higher in group 1 than in group 2. There were no significant differences in means of basal s-IRI, HOMA-R and s-CPR between groups. However, means of HOMA-β, insulinogenic index, postprandial s-IRI, s-CPR and p-active GLP-1-S or p-active GLP-1-S/PG values after TM were significantly lower in group 1 than in group 2. Conclusions: These results indicate that a response of p-active GLP-1-S after TM in obese Japanese patients with T2DM was decreased and secretion of GLP-1 relative to PG was impaired. The method of enhancing function of active GLP-1 may be useful for treatment in some of patients with diabetes mellitus.
文摘When a statistical test of hypothesis for a population mean is performed, we are faced with the possibility of committing a Type II error by not rejecting the null hypothesis when in fact the population mean has changed. We consider this issue and quantify matters in a manner that differs a bit from what is commonly done. In particular, we define the probability distribution function for Type II errors. We then explore some interesting properties that we have not seen mentioned elsewhere for this probability distribution function. Finally, we discuss several Maple procedures that can be used to perform various calculations using the distribution.
基金supported by the National Natural Science Foundation of China(7117116470471057)
文摘This paper proposes a simple constant-stress accel- erated life test (ALT) model from Burr type XII distribution when the data are Type-I progressively hybrid censored. The maximum likelihood estimation (MLE) of the parameters is obtained through the numerical method for solving the likelihood equations. Approxi- mate confidence interval (CI), based on normal approximation to the asymptotic distribution of MLE and percentile bootstrap Cl is derived. Finally, a numerical example is introduced and then a Monte Carlo simulation study is carried out to illustrate the pro- posed method.