针对低信噪比条件下,谱减法和频谱法构建最小均方(Least Mean Square,LMS)自适应滤波器期望响应误差大的问题,在分析LMS自适应滤波原理的基础上,提出用自相关法构建LMS自适应滤波器期望响应。首先,根据噪声在不同时刻互不相关的特点,对...针对低信噪比条件下,谱减法和频谱法构建最小均方(Least Mean Square,LMS)自适应滤波器期望响应误差大的问题,在分析LMS自适应滤波原理的基础上,提出用自相关法构建LMS自适应滤波器期望响应。首先,根据噪声在不同时刻互不相关的特点,对输入信号进行采样延迟;然后,为了从低信噪比环境中检测出周期信号,对延迟后信号求自相关;最后,将自相关信号作为期望响应。通过仿真分析对方法进行了验证,可以在低信噪比下准确构建期望响应进行LMS自适应滤波。展开更多
To reduce the fuel consumption and emissions and also enhance the molten aluminum quality, a mathematical model with user-developed melting model and burning capacity model, were established according to the features ...To reduce the fuel consumption and emissions and also enhance the molten aluminum quality, a mathematical model with user-developed melting model and burning capacity model, were established according to the features of melting process of regenerative aluminum melting furnaces. Based on validating results by heat balance test for an aluminum melting furnace, CFD （computational fluid dynamics） technique, in association with statistical experimental design were used to optimize the melting process of the aluminum melting furnace. Four important factors influencing the melting time, such as horizontal angle between burners, height-to-radius ratio, natural gas mass flow and air preheated temperature, were identified by PLACKETT-BURMAN design. A steepest descent method was undertaken to determine the optimal regions of these factors. Response surface methodology with BOX-BEHNKEN design was adopted to further investigate the mutual interactions between these variables on RSD （relative standard deviation） of aluminum temperature, RSD of furnace temperature and melting time. Multiple-response optimization by desirability function approach was used to determine the optimum melting process parameters. The results indicate that the interaction between the height-to-radius ratio and horizontal angle between burners affects the response variables significantly. The predicted results show that the minimum RSD of aluminum temperature （12.13%）, RSD of furnace temperature （18.50%） and melting time （3.9 h） could be obtained under the optimum conditions of horizontal angle between burners as 64°, height-to-radius ratio as 0.3, natural gas mass flow as 599 m3/h, and air preheated temperature as 639 ℃. These predicted values were further verified by validation experiments. The excellent correlation between the predicted and experimental values confirms the validity and practicability of this statistical optimum strategy.展开更多
The purpose of this study was to detect social desirable response bias on Chinese nurses’ attitudes and beliefs toward sexuality care of cancer patients. A cross-sectional self-reported questionnaire based survey was...The purpose of this study was to detect social desirable response bias on Chinese nurses’ attitudes and beliefs toward sexuality care of cancer patients. A cross-sectional self-reported questionnaire based survey was used. Measures included a 12-item Inventory of Sexuality Attitude and Belief Survey (SABS) and a 10-item Marlowe-Crowne Social Desirability Scale. Total social desirability scores were significantly correlated with four individual items of the SABS, and significantly predicted the total SABS scores (β=﹣0.155, p= 0.028). Before controlling social desirability variable, nurses’ age, marital status, years of working experience, and working units were significantly correlated with total SABS scores. After controlling social desirability variable, only nurses’ age and working units were statistically significant predictors of SABS. Social desirable response bias had impacts on Chinese nurses’ attitudes and beliefs toward sexuality care of cancer patients. Study findings demonstrated that social desirable response bias would potentially jeopardize human sexuality assessment and counseling in nursing practice. Controlling social desirable response should consider using a social desirability scale to detect and control potential social desirability bias during data analysis.展开更多
优化了虾壳中甲壳素提取工艺及其对糖尿病小鼠的影响。首先采用期望函数和响应面法优化了EDTA提取虾壳脱钙脱蛋白质工艺,并通过四氧嘧啶建立糖尿病小鼠模型,分别考察甲壳素、二甲双胍和二者联合给药1个月后,糖尿病小鼠的体重、血糖等指...优化了虾壳中甲壳素提取工艺及其对糖尿病小鼠的影响。首先采用期望函数和响应面法优化了EDTA提取虾壳脱钙脱蛋白质工艺,并通过四氧嘧啶建立糖尿病小鼠模型,分别考察甲壳素、二甲双胍和二者联合给药1个月后,糖尿病小鼠的体重、血糖等指标的变化。最终确定最佳提取工艺为:EDTA脱钙条件p H 11,EDTA浓度11%,反应时间2 h,料液比1∶14(g/m L),之后过滤,烘干,双氧水脱色,烘干,既得甲壳素提取物。验证试验与预测值相对误差为2.8%,较优化前提高了20.3%。降血糖结果显示,与模型组,或是甲壳素和二甲双胍单独给药组相比,二者联合给药能够缓解小鼠体重下降(P<0.05),显著降低糖尿病小鼠的血清总胆固醇、甘油三酯、血糖、糖化血红蛋白含量(P<0.01,P<0.01,P<0.01,P<0.01),增加胰岛素表达(P<0.05)。也能缓解对胰腺组织的损伤(P<0.05)。甲壳素能够增强二甲双胍的抗糖尿病功效,在临床上应用有重要的意义。展开更多
文摘针对低信噪比条件下,谱减法和频谱法构建最小均方(Least Mean Square,LMS)自适应滤波器期望响应误差大的问题,在分析LMS自适应滤波原理的基础上,提出用自相关法构建LMS自适应滤波器期望响应。首先,根据噪声在不同时刻互不相关的特点,对输入信号进行采样延迟;然后,为了从低信噪比环境中检测出周期信号,对延迟后信号求自相关;最后,将自相关信号作为期望响应。通过仿真分析对方法进行了验证,可以在低信噪比下准确构建期望响应进行LMS自适应滤波。
基金Project(2009BSXT022) supported by the Dissertation Innovation Foundation of Central South University, ChinaProject(07JJ4016) supported by Natural Science Foundation of Hunan Province, ChinaProject(U0937604) supported by National Natural Science Foundation of China
文摘To reduce the fuel consumption and emissions and also enhance the molten aluminum quality, a mathematical model with user-developed melting model and burning capacity model, were established according to the features of melting process of regenerative aluminum melting furnaces. Based on validating results by heat balance test for an aluminum melting furnace, CFD （computational fluid dynamics） technique, in association with statistical experimental design were used to optimize the melting process of the aluminum melting furnace. Four important factors influencing the melting time, such as horizontal angle between burners, height-to-radius ratio, natural gas mass flow and air preheated temperature, were identified by PLACKETT-BURMAN design. A steepest descent method was undertaken to determine the optimal regions of these factors. Response surface methodology with BOX-BEHNKEN design was adopted to further investigate the mutual interactions between these variables on RSD （relative standard deviation） of aluminum temperature, RSD of furnace temperature and melting time. Multiple-response optimization by desirability function approach was used to determine the optimum melting process parameters. The results indicate that the interaction between the height-to-radius ratio and horizontal angle between burners affects the response variables significantly. The predicted results show that the minimum RSD of aluminum temperature （12.13%）, RSD of furnace temperature （18.50%） and melting time （3.9 h） could be obtained under the optimum conditions of horizontal angle between burners as 64°, height-to-radius ratio as 0.3, natural gas mass flow as 599 m3/h, and air preheated temperature as 639 ℃. These predicted values were further verified by validation experiments. The excellent correlation between the predicted and experimental values confirms the validity and practicability of this statistical optimum strategy.
文摘The purpose of this study was to detect social desirable response bias on Chinese nurses’ attitudes and beliefs toward sexuality care of cancer patients. A cross-sectional self-reported questionnaire based survey was used. Measures included a 12-item Inventory of Sexuality Attitude and Belief Survey (SABS) and a 10-item Marlowe-Crowne Social Desirability Scale. Total social desirability scores were significantly correlated with four individual items of the SABS, and significantly predicted the total SABS scores (β=﹣0.155, p= 0.028). Before controlling social desirability variable, nurses’ age, marital status, years of working experience, and working units were significantly correlated with total SABS scores. After controlling social desirability variable, only nurses’ age and working units were statistically significant predictors of SABS. Social desirable response bias had impacts on Chinese nurses’ attitudes and beliefs toward sexuality care of cancer patients. Study findings demonstrated that social desirable response bias would potentially jeopardize human sexuality assessment and counseling in nursing practice. Controlling social desirable response should consider using a social desirability scale to detect and control potential social desirability bias during data analysis.
文摘优化了虾壳中甲壳素提取工艺及其对糖尿病小鼠的影响。首先采用期望函数和响应面法优化了EDTA提取虾壳脱钙脱蛋白质工艺,并通过四氧嘧啶建立糖尿病小鼠模型,分别考察甲壳素、二甲双胍和二者联合给药1个月后,糖尿病小鼠的体重、血糖等指标的变化。最终确定最佳提取工艺为:EDTA脱钙条件p H 11,EDTA浓度11%,反应时间2 h,料液比1∶14(g/m L),之后过滤,烘干,双氧水脱色,烘干,既得甲壳素提取物。验证试验与预测值相对误差为2.8%,较优化前提高了20.3%。降血糖结果显示,与模型组,或是甲壳素和二甲双胍单独给药组相比,二者联合给药能够缓解小鼠体重下降(P<0.05),显著降低糖尿病小鼠的血清总胆固醇、甘油三酯、血糖、糖化血红蛋白含量(P<0.01,P<0.01,P<0.01,P<0.01),增加胰岛素表达(P<0.05)。也能缓解对胰腺组织的损伤(P<0.05)。甲壳素能够增强二甲双胍的抗糖尿病功效,在临床上应用有重要的意义。
