Background: Components of height have been found to be positively associated with blood pressure (BP) both in developed and developing nations. However, amongst Cameroon secondary school adolescents, the relationship ...Background: Components of height have been found to be positively associated with blood pressure (BP) both in developed and developing nations. However, amongst Cameroon secondary school adolescents, the relationship between heights, SH and SH/H with BP has rarely been studied. The purpose of this study was to determine the proportion of secondary school adolescents with elevated BP and high BP and to evaluate the relationship between the different components of linear growth with BP. Methods: An institution-based cross-sectional study involving 602 adolescents (399 girls and 203 boys, mean age 14.9 ± 2.3 years) attending some public and private secondary schools in the Bamenda municipality of the North West Region of Cameroon. Anthropometric and BP measurements were carried out following standard procedures. Pearson correlation and linear regression were used to determine the relationship between the various components of height (height, SH, SH/H) with BP amongst the children. Results: The overall prevalence of elevated BP and hypertension amongst the study participants was 21.9% and 15.6% respectively (with 8.3% and 7.3% of the hypertensive children in Stage I and Stage II respectively). However, there were no significant gender differences in the prevalence of elevated BP and high BP (p = 0.497). Girls had a significantly (p Conclusion: This study has demonstrated that height was positively associated with SBP amongst children and adolescents. Thus, height can be used in predicting adolescents with a high risk of developing high BP in our setting.展开更多
The problem of stability for singular systems with two additive time-varying delay components is investigated. By constructing a simple type of Lyapunov-Krasovskii functional and utilizing free matrix variables in app...The problem of stability for singular systems with two additive time-varying delay components is investigated. By constructing a simple type of Lyapunov-Krasovskii functional and utilizing free matrix variables in approximating certain integral quadratic terms, a delay-dependent stability criterion is established for the considered systems to be regular, impulse free, and stable in terms of linear matrix inequalities （LMIs）. Based on this criterion, some new stability conditions for singular systems with a single delay in a range and regular systems with two additive time-varying delay components are proposed. These developed results have advantages over some previous ones in that they have fewer matrix variables yet less conservatism. Finally, two numerical examples are employed to illustrate the effectiveness of the obtained theoretical results.展开更多
Background: Although abduction of the acetabular component is considered to predict factors for polyethylene wear attributable to osteolysis, other radiographic factors have yet to be elucidated. The purpose of the pr...Background: Although abduction of the acetabular component is considered to predict factors for polyethylene wear attributable to osteolysis, other radiographic factors have yet to be elucidated. The purpose of the present study was to evaluate whether anteversion or change in implantation angle of the acetabular component influences polyethylene linear wear by using standing and supine radiographs of the hip joint. Methods: Standing and supine plain anteroposterior radiographs of 62 hip joints in which cementless total hip arthroplasty was performed were examined for polyethylene linear wear rate (mm/year), pelvic inclination, and radiological inclination and anatomic anteversion of the acetabular component. Results: All correlation coefficients of measurements of polyethylene linear wear, pelvic inclination angle, anatomical anteversion angle and radiological inclination angle were calculated highly. And by the three-dimensional numerical analysis, anatomic anteversion of the acetabular component had at least some effect on the degree of polyethylene wear. Conclusion: This study suggests that increased anteversion of the acetabular component reduces polyethylene linear wear in metal-on-polyethylene total hiparthroplasty.展开更多
As the market competition of steel mills is severe,deoxidization alloying is an important link in the metallurgical process.To solve this problem,principal component regression analysis is adopted to reduce the dimens...As the market competition of steel mills is severe,deoxidization alloying is an important link in the metallurgical process.To solve this problem,principal component regression analysis is adopted to reduce the dimension of influencing factors,and a reasonable and reliable prediction model of element yield is established.Based on the constraint conditions such as target cost function constraint,yield constraint and non-negative constraint,linear programming is adopted to design the lowest cost batting scheme that meets the national standards and production requirements.The research results provide a reliable optimization model for the deoxidization and alloying process of steel mills,which is of positive significance for improving the market competitiveness of steel mills,reducing waste discharge and protecting the environment.展开更多
An improved measurement method of circularly-polarized (CP) antennas based on linear-component amplitudes is proposed in this paper. By utilizing two sets of orthogonal linear polarization (LP) amplitudes, measurement...An improved measurement method of circularly-polarized (CP) antennas based on linear-component amplitudes is proposed in this paper. By utilizing two sets of orthogonal linear polarization (LP) amplitudes, measurement on axial ratio (AR) of CP antennas can be realized without phase information. However, the rotation sense of the co-polarization cannot be determined due to the absence of the phase information. Above problem is discussed here for the first time, and a solution is presented to determine the rotation sense of the co-polarization by using common auxiliary CP antennas. In addition, there will be some particular cases with large errors in actual measurement. Here a corresponding solution method is given. Finally, co-polarization and cross-polarization patterns can be further obtained from AR results. To verify this improved method, a self-developed CP microstrip array was measured. The measured results are in agreement with the simulated results, which prove this method is correct, effective and practical.展开更多
How to extract optimal composite attributes from a variety of conventional seismic attributes to detect reservoir features is a reservoir predication key,which is usually solved by reducing dimensionality.Principle co...How to extract optimal composite attributes from a variety of conventional seismic attributes to detect reservoir features is a reservoir predication key,which is usually solved by reducing dimensionality.Principle component analysis（PCA） is the most widely-used linear dimensionality reduction method at present.However,the relationships between seismic attributes and reservoir features are non-linear,so seismic attribute dimensionality reduction based on linear transforms can＇t solve non-linear problems well,reducing reservoir prediction precision.As a new non-linear learning method,manifold learning supplies a new method for seismic attribute analysis.It can discover the intrinsic features and rules hidden in the data by computing low-dimensional,neighborhood-preserving embeddings of high-dimensional inputs.In this paper,we try to extract seismic attributes using locally linear embedding（LLE）,realizing inter-horizon attributes dimensionality reduction of 3D seismic data first and discuss the optimization of its key parameters.Combining model analysis and case studies,we compare the dimensionality reduction and clustering effects of LLE and PCA,both of which indicate that LLE can retain the intrinsic structure of the inputs.The composite attributes and clustering results based on LLE better characterize the distribution of sedimentary facies,reservoir,and even reservoir fluids.展开更多
目的:建立一测多评法(QAMS)同时测定蒙古族成药每粒清热八味胶囊中胆红素、羟基红花黄色素A、芦丁、胡黄连苷Ⅱ、胡黄连苷Ⅰ、肉桂酸、槲皮素、紫堇灵、山柰素的质量。方法:采用高效液相色谱法,安捷伦Zorbax Eclipse Plus C18色谱柱(250...目的:建立一测多评法(QAMS)同时测定蒙古族成药每粒清热八味胶囊中胆红素、羟基红花黄色素A、芦丁、胡黄连苷Ⅱ、胡黄连苷Ⅰ、肉桂酸、槲皮素、紫堇灵、山柰素的质量。方法:采用高效液相色谱法,安捷伦Zorbax Eclipse Plus C18色谱柱(250 mm×4.6 mm,5μm),以乙腈-0.4%磷酸水溶液为流动相,梯度洗脱,流速为1.0 m L·min^(–1),检测波长分别为275、370、403 nm,柱温为35℃。以羟基红花黄色素A和胡黄连苷Ⅰ为双标化合物,使用双标线性校正法(LCTRC)预测tR。以胡黄连苷Ⅰ为内参物,建立与其他8个成分的相对校正因子,并计算每粒中9个待测成分的质量,实现一测多评。同时与外标法进行比较,验证QAMS的准确性和可行性。结果:9个成分在各自质量浓度范围内的线性关系良好(r≥0.9990),平均加样回收率为93.0%~99.8%,RSD为0.23%~1.53%;建立的QAMS可用于测定每粒清热八味胶囊中9个指标成分的质量,并对6批清热八味胶囊进行测定,其计算值与测定值的差异无统计学意义。结论:QAMS测定清热八味胶囊中9个成分准确且可行,可用于清热八味胶囊的质量控制。展开更多
In principal component analysis （PCA） algorithms for face recognition, to reduce the influence of the eigenvectors which relate to the changes of the illumination on abstract features, a modified PCA （MPCA） algori...In principal component analysis （PCA） algorithms for face recognition, to reduce the influence of the eigenvectors which relate to the changes of the illumination on abstract features, a modified PCA （MPCA） algorithm is proposed. The method is based on the idea of reducing the influence of the eigenvectors associated with the large eigenvalues by normalizing the feature vector element by its corresponding standard deviation. The Yale face database and Yale face database B are used to verify the method. The simulation results show that, for front face and even under the condition of limited variation in the facial poses, the proposed method results in better performance than the conventional PCA and linear discriminant analysis （LDA） approaches, and the computational cost remains the same as that of the PCA, and much less than that of the LDA.展开更多
文摘Background: Components of height have been found to be positively associated with blood pressure (BP) both in developed and developing nations. However, amongst Cameroon secondary school adolescents, the relationship between heights, SH and SH/H with BP has rarely been studied. The purpose of this study was to determine the proportion of secondary school adolescents with elevated BP and high BP and to evaluate the relationship between the different components of linear growth with BP. Methods: An institution-based cross-sectional study involving 602 adolescents (399 girls and 203 boys, mean age 14.9 ± 2.3 years) attending some public and private secondary schools in the Bamenda municipality of the North West Region of Cameroon. Anthropometric and BP measurements were carried out following standard procedures. Pearson correlation and linear regression were used to determine the relationship between the various components of height (height, SH, SH/H) with BP amongst the children. Results: The overall prevalence of elevated BP and hypertension amongst the study participants was 21.9% and 15.6% respectively (with 8.3% and 7.3% of the hypertensive children in Stage I and Stage II respectively). However, there were no significant gender differences in the prevalence of elevated BP and high BP (p = 0.497). Girls had a significantly (p Conclusion: This study has demonstrated that height was positively associated with SBP amongst children and adolescents. Thus, height can be used in predicting adolescents with a high risk of developing high BP in our setting.
基金supported by National Natural Science Foundation of China(No.11071193)Research Foundation of Education Bureau of Shan xi Province(No.11JK0509)Research Foundation of Baoji University of Arts and Sciences(No.ZK11044)
文摘The problem of stability for singular systems with two additive time-varying delay components is investigated. By constructing a simple type of Lyapunov-Krasovskii functional and utilizing free matrix variables in approximating certain integral quadratic terms, a delay-dependent stability criterion is established for the considered systems to be regular, impulse free, and stable in terms of linear matrix inequalities （LMIs）. Based on this criterion, some new stability conditions for singular systems with a single delay in a range and regular systems with two additive time-varying delay components are proposed. These developed results have advantages over some previous ones in that they have fewer matrix variables yet less conservatism. Finally, two numerical examples are employed to illustrate the effectiveness of the obtained theoretical results.
文摘Background: Although abduction of the acetabular component is considered to predict factors for polyethylene wear attributable to osteolysis, other radiographic factors have yet to be elucidated. The purpose of the present study was to evaluate whether anteversion or change in implantation angle of the acetabular component influences polyethylene linear wear by using standing and supine radiographs of the hip joint. Methods: Standing and supine plain anteroposterior radiographs of 62 hip joints in which cementless total hip arthroplasty was performed were examined for polyethylene linear wear rate (mm/year), pelvic inclination, and radiological inclination and anatomic anteversion of the acetabular component. Results: All correlation coefficients of measurements of polyethylene linear wear, pelvic inclination angle, anatomical anteversion angle and radiological inclination angle were calculated highly. And by the three-dimensional numerical analysis, anatomic anteversion of the acetabular component had at least some effect on the degree of polyethylene wear. Conclusion: This study suggests that increased anteversion of the acetabular component reduces polyethylene linear wear in metal-on-polyethylene total hiparthroplasty.
文摘As the market competition of steel mills is severe,deoxidization alloying is an important link in the metallurgical process.To solve this problem,principal component regression analysis is adopted to reduce the dimension of influencing factors,and a reasonable and reliable prediction model of element yield is established.Based on the constraint conditions such as target cost function constraint,yield constraint and non-negative constraint,linear programming is adopted to design the lowest cost batting scheme that meets the national standards and production requirements.The research results provide a reliable optimization model for the deoxidization and alloying process of steel mills,which is of positive significance for improving the market competitiveness of steel mills,reducing waste discharge and protecting the environment.
文摘An improved measurement method of circularly-polarized (CP) antennas based on linear-component amplitudes is proposed in this paper. By utilizing two sets of orthogonal linear polarization (LP) amplitudes, measurement on axial ratio (AR) of CP antennas can be realized without phase information. However, the rotation sense of the co-polarization cannot be determined due to the absence of the phase information. Above problem is discussed here for the first time, and a solution is presented to determine the rotation sense of the co-polarization by using common auxiliary CP antennas. In addition, there will be some particular cases with large errors in actual measurement. Here a corresponding solution method is given. Finally, co-polarization and cross-polarization patterns can be further obtained from AR results. To verify this improved method, a self-developed CP microstrip array was measured. The measured results are in agreement with the simulated results, which prove this method is correct, effective and practical.
基金National Key Science & Technology Special Projects(Grant No.2008ZX05000-004)CNPC Projects(Grant No.2008E-0610-10).
文摘How to extract optimal composite attributes from a variety of conventional seismic attributes to detect reservoir features is a reservoir predication key,which is usually solved by reducing dimensionality.Principle component analysis（PCA） is the most widely-used linear dimensionality reduction method at present.However,the relationships between seismic attributes and reservoir features are non-linear,so seismic attribute dimensionality reduction based on linear transforms can＇t solve non-linear problems well,reducing reservoir prediction precision.As a new non-linear learning method,manifold learning supplies a new method for seismic attribute analysis.It can discover the intrinsic features and rules hidden in the data by computing low-dimensional,neighborhood-preserving embeddings of high-dimensional inputs.In this paper,we try to extract seismic attributes using locally linear embedding（LLE）,realizing inter-horizon attributes dimensionality reduction of 3D seismic data first and discuss the optimization of its key parameters.Combining model analysis and case studies,we compare the dimensionality reduction and clustering effects of LLE and PCA,both of which indicate that LLE can retain the intrinsic structure of the inputs.The composite attributes and clustering results based on LLE better characterize the distribution of sedimentary facies,reservoir,and even reservoir fluids.
文摘目的:建立一测多评法(QAMS)同时测定蒙古族成药每粒清热八味胶囊中胆红素、羟基红花黄色素A、芦丁、胡黄连苷Ⅱ、胡黄连苷Ⅰ、肉桂酸、槲皮素、紫堇灵、山柰素的质量。方法:采用高效液相色谱法,安捷伦Zorbax Eclipse Plus C18色谱柱(250 mm×4.6 mm,5μm),以乙腈-0.4%磷酸水溶液为流动相,梯度洗脱,流速为1.0 m L·min^(–1),检测波长分别为275、370、403 nm,柱温为35℃。以羟基红花黄色素A和胡黄连苷Ⅰ为双标化合物,使用双标线性校正法(LCTRC)预测tR。以胡黄连苷Ⅰ为内参物,建立与其他8个成分的相对校正因子,并计算每粒中9个待测成分的质量,实现一测多评。同时与外标法进行比较,验证QAMS的准确性和可行性。结果:9个成分在各自质量浓度范围内的线性关系良好(r≥0.9990),平均加样回收率为93.0%~99.8%,RSD为0.23%~1.53%;建立的QAMS可用于测定每粒清热八味胶囊中9个指标成分的质量,并对6批清热八味胶囊进行测定,其计算值与测定值的差异无统计学意义。结论:QAMS测定清热八味胶囊中9个成分准确且可行,可用于清热八味胶囊的质量控制。
文摘In principal component analysis （PCA） algorithms for face recognition, to reduce the influence of the eigenvectors which relate to the changes of the illumination on abstract features, a modified PCA （MPCA） algorithm is proposed. The method is based on the idea of reducing the influence of the eigenvectors associated with the large eigenvalues by normalizing the feature vector element by its corresponding standard deviation. The Yale face database and Yale face database B are used to verify the method. The simulation results show that, for front face and even under the condition of limited variation in the facial poses, the proposed method results in better performance than the conventional PCA and linear discriminant analysis （LDA） approaches, and the computational cost remains the same as that of the PCA, and much less than that of the LDA.
