The modified suction caisson(MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson(RSC)...The modified suction caisson(MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson(RSC). The MSC can provide larger lateral bearing capacity and limit the deflection compared with the RSC. Therefore, the MSC can be much more appropriate to use as an offshore wind turbine foundation. Model tests on the MSC in saturated sand subjected to monotonic lateral loading were carried out to investigate the effects of external structure sizes on the sand surface deformation and the earth pressure distribution along the embedded depth. Test results show that the deformation range of the sand surface increases with the increasing width and length of the external structure. The magnitude of sand upheaval around the MSC is smaller than that of the RSC and the sand upheaval value around the MSC in the loading direction decreases with the increasing external structure dimensions. The net earth pressure in the loading direction acting on the internal compartment of the MSC is smaller than that of the RSC at the same embedded depth. The maximum net earth pressure acting on the external structure outer wall in the loading direction is larger than that of the internal compartment, indicating that a considerable amount of the lateral load and moment is resisted by the external skirt structure.展开更多
通过在U-tree中添加时间戳和速度矢量等时空因素,提出一种基于U-tree的高效率当前及未来不确定位置信息检索的索引结构TPU-tree,可以支持多维空间中不确定移动对象的索引,并提出了一种改进的基于p-bound的MP_BBRQ(modifiedp-bound based...通过在U-tree中添加时间戳和速度矢量等时空因素,提出一种基于U-tree的高效率当前及未来不确定位置信息检索的索引结构TPU-tree,可以支持多维空间中不确定移动对象的索引,并提出了一种改进的基于p-bound的MP_BBRQ(modifiedp-bound based range query)域查询处理算法,能够引入搜索区域进行预裁剪以减少查询精炼阶段所需代价偏高的积分计算.实验仿真表明,采用MP_BBRQ算法的TPU-tree概率查询性能极大地优于传统的TPR-tree索引,且更新性能与传统索引大致相当,具有良好的实用价值.展开更多
在立方球体坐标系下推导出浅水波方程的形式,使用M DQ方法和4阶R ung-K u tta方法求解该方程,计算了余弦钟绕球平流算例的三种情况,并且给出了该算例在立方球体坐标系下6个区间的速度矢量的表达式.为了解决由于边界插值所引起的数值不...在立方球体坐标系下推导出浅水波方程的形式,使用M DQ方法和4阶R ung-K u tta方法求解该方程,计算了余弦钟绕球平流算例的三种情况,并且给出了该算例在立方球体坐标系下6个区间的速度矢量的表达式.为了解决由于边界插值所引起的数值不稳定性,引入了4阶的人工粘性项(-4).通过对测试方案的求解和分析,可以看出该方法的优点:①完全显式格式;②时间上的4阶精度;③仅仅通过改变一个参数就可以获得空间的高阶精度;④该数值方案有较强的适用性.展开更多
Chemical compounds are modeled as graphs.The atoms of molecules represent the graph vertices while chemical bonds between the atoms express the edges.The topological indices representing the molecular graph correspond...Chemical compounds are modeled as graphs.The atoms of molecules represent the graph vertices while chemical bonds between the atoms express the edges.The topological indices representing the molecular graph corresponds to the different chemical properties of compounds.Let a,b be are two positive integers,andΓ(Z_(a)×Z_(b))be the zero-divisor graph of the commutative ring Z_(a)×Z_(b).In this article some direct questions have been answered that can be utilized latterly in different applications.This study starts with simple computations,leading to a quite complex ring theoretic problems to prove certain properties.The theory of finite commutative rings is useful due to its different applications in the fields of advanced mechanics,communication theory,cryptography,combinatorics,algorithms analysis,and engineering.In this paper we determine the distance-based topological polynomials and indices of the zero-divisor graph of the commutative ring Z_(p^(2))×Z_(q)(for p,q as prime numbers)with the help of graphical structure analysis.The study outcomes help in understanding the fundamental relation between ring-theoretic and graph-theoretic properties of a zero-divisor graphΓ(G).展开更多
Many physicists believe dark matter accounts for flat velocity curves in spiral galaxies and find further evidence for dark matter in observations of the colliding “bullet cluster” galaxies 1E0657-56. Others claim a...Many physicists believe dark matter accounts for flat velocity curves in spiral galaxies and find further evidence for dark matter in observations of the colliding “bullet cluster” galaxies 1E0657-56. Others claim a modified law of gravity called MOND (MOdified Newtonian Dynamics) explains galactic velocity curves better than dark matter. Merritt recently argued for MOND (arXiv:1703.02389) by claiming dark matter models cannot account for the MOND acceleration threshold a0≈1.2x10-8cm/sec2 and the (Vobserved/VNewtonian) relation. However, this note shows that the HLSS model involving dark matter accounts for both the MOND acceleration and the (Vobserved/VNewtonian) relation. After this paper was accepted for publication, I learned that Man Ho Chan previously reached the same conclusion (arXiv:1310.6801) using a dark matter based analysis independent of the holographic approach used in this paper.展开更多
Objective:Our aim was to prospectively compare the Accuracy of Acute Physiology and Chronic Health Evaluation(APACHE)II,Bedside Index of Severity in Acute Pancreatitis(BISAP),Ranson’s score and modified Computed Tomo...Objective:Our aim was to prospectively compare the Accuracy of Acute Physiology and Chronic Health Evaluation(APACHE)II,Bedside Index of Severity in Acute Pancreatitis(BISAP),Ranson’s score and modified Computed Tomography Severity Index(CTSI)in predicting the severity of acute pancreatitis based on Atlanta 2012 definitions in a tertiary care hospital in northern India.Methods:Fifty patients with acute pancreatitis admitted to our hospital during the period of March 2015 to September 2016 were included in the study.APACHE II,BISAP and Ranson’s score were calculated for all the cases.Modified CTSI was also determined based on a pancreatic protocol contrast enhanced computerized tomography(CT).Optimal cut-offs for these scoring systems and the area under the curve(AUC)were evaluated based on the receiver operating characteristics(ROC)curve and these scoring systems were compared prospectively.Results:Of the 50 cases,14 were graded as severe acute pancreatitis.Pancreatic necrosis was present in 15 patients,while 14 developed persistent organ failure and 14 needed intensive care unit(ICU)admission.The AUC for modified CTSI was consistently the highest for predicting severe acute pancreatitis(0.919),pancreatic necrosis(0.993),organ failure(0.893)and ICU admission(0.993).APACHE II was the second most accurate in predicting severe acute pancreatitis(AUC 0.834)and organ failure(0.831).APACHE II had a high sensitivity for predicting pancreatic necrosis(93.33%),organ failure(92.86%)and ICU admission(92.31%),and also had a high negative predictive value for predicting pancreatic necrosis(96.15%),organ failure(96.15%)and ICU admission(95.83%).Conclusion:APACHE II is a useful prognostic scoring system for predicting the severity of acute pancreatitis and can be a crucial aid in determining the group of patients that have a high chance of need for tertiary care during the course of their illness and therefore need early resuscitation and prompt referral,especially in resource-limited developing countries.展开更多
音频分类是音频信号处理中一项重要的预处理工作。该文描述了一种基于能量的分类方法,将音频信号分为语音和音乐2种类型。分类的过程分为3个阶段,首先计算优化低能量率MLER(modified low energy ratio)作为特征,然后利用初级分类器得到...音频分类是音频信号处理中一项重要的预处理工作。该文描述了一种基于能量的分类方法,将音频信号分为语音和音乐2种类型。分类的过程分为3个阶段,首先计算优化低能量率MLER(modified low energy ratio)作为特征,然后利用初级分类器得到初步分类的结果,最后利用音频类别的前后相关性,使用上下文分类器修正初始分类得到最终分类的结果。该文重点对MLER中参数的合理选取范围进行了讨论,并对传统的初始分类器作了改进,用非参数分类器和参数分类器代替原有的Bayes硬判决的方法,避免了由于门限选择不当所带来的分类错误。实验表明,使用参数分类器时,对纯语音和纯音乐分类效果很好,正确率达99%以上。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51639002 and 51379118)the SDUST Research Fund(Grant No.2015KYTD104)
文摘The modified suction caisson(MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson(RSC). The MSC can provide larger lateral bearing capacity and limit the deflection compared with the RSC. Therefore, the MSC can be much more appropriate to use as an offshore wind turbine foundation. Model tests on the MSC in saturated sand subjected to monotonic lateral loading were carried out to investigate the effects of external structure sizes on the sand surface deformation and the earth pressure distribution along the embedded depth. Test results show that the deformation range of the sand surface increases with the increasing width and length of the external structure. The magnitude of sand upheaval around the MSC is smaller than that of the RSC and the sand upheaval value around the MSC in the loading direction decreases with the increasing external structure dimensions. The net earth pressure in the loading direction acting on the internal compartment of the MSC is smaller than that of the RSC at the same embedded depth. The maximum net earth pressure acting on the external structure outer wall in the loading direction is larger than that of the internal compartment, indicating that a considerable amount of the lateral load and moment is resisted by the external skirt structure.
文摘通过在U-tree中添加时间戳和速度矢量等时空因素,提出一种基于U-tree的高效率当前及未来不确定位置信息检索的索引结构TPU-tree,可以支持多维空间中不确定移动对象的索引,并提出了一种改进的基于p-bound的MP_BBRQ(modifiedp-bound based range query)域查询处理算法,能够引入搜索区域进行预裁剪以减少查询精炼阶段所需代价偏高的积分计算.实验仿真表明,采用MP_BBRQ算法的TPU-tree概率查询性能极大地优于传统的TPR-tree索引,且更新性能与传统索引大致相当,具有良好的实用价值.
文摘在立方球体坐标系下推导出浅水波方程的形式,使用M DQ方法和4阶R ung-K u tta方法求解该方程,计算了余弦钟绕球平流算例的三种情况,并且给出了该算例在立方球体坐标系下6个区间的速度矢量的表达式.为了解决由于边界插值所引起的数值不稳定性,引入了4阶的人工粘性项(-4).通过对测试方案的求解和分析,可以看出该方法的优点:①完全显式格式;②时间上的4阶精度;③仅仅通过改变一个参数就可以获得空间的高阶精度;④该数值方案有较强的适用性.
文摘Chemical compounds are modeled as graphs.The atoms of molecules represent the graph vertices while chemical bonds between the atoms express the edges.The topological indices representing the molecular graph corresponds to the different chemical properties of compounds.Let a,b be are two positive integers,andΓ(Z_(a)×Z_(b))be the zero-divisor graph of the commutative ring Z_(a)×Z_(b).In this article some direct questions have been answered that can be utilized latterly in different applications.This study starts with simple computations,leading to a quite complex ring theoretic problems to prove certain properties.The theory of finite commutative rings is useful due to its different applications in the fields of advanced mechanics,communication theory,cryptography,combinatorics,algorithms analysis,and engineering.In this paper we determine the distance-based topological polynomials and indices of the zero-divisor graph of the commutative ring Z_(p^(2))×Z_(q)(for p,q as prime numbers)with the help of graphical structure analysis.The study outcomes help in understanding the fundamental relation between ring-theoretic and graph-theoretic properties of a zero-divisor graphΓ(G).
文摘Many physicists believe dark matter accounts for flat velocity curves in spiral galaxies and find further evidence for dark matter in observations of the colliding “bullet cluster” galaxies 1E0657-56. Others claim a modified law of gravity called MOND (MOdified Newtonian Dynamics) explains galactic velocity curves better than dark matter. Merritt recently argued for MOND (arXiv:1703.02389) by claiming dark matter models cannot account for the MOND acceleration threshold a0≈1.2x10-8cm/sec2 and the (Vobserved/VNewtonian) relation. However, this note shows that the HLSS model involving dark matter accounts for both the MOND acceleration and the (Vobserved/VNewtonian) relation. After this paper was accepted for publication, I learned that Man Ho Chan previously reached the same conclusion (arXiv:1310.6801) using a dark matter based analysis independent of the holographic approach used in this paper.
文摘Objective:Our aim was to prospectively compare the Accuracy of Acute Physiology and Chronic Health Evaluation(APACHE)II,Bedside Index of Severity in Acute Pancreatitis(BISAP),Ranson’s score and modified Computed Tomography Severity Index(CTSI)in predicting the severity of acute pancreatitis based on Atlanta 2012 definitions in a tertiary care hospital in northern India.Methods:Fifty patients with acute pancreatitis admitted to our hospital during the period of March 2015 to September 2016 were included in the study.APACHE II,BISAP and Ranson’s score were calculated for all the cases.Modified CTSI was also determined based on a pancreatic protocol contrast enhanced computerized tomography(CT).Optimal cut-offs for these scoring systems and the area under the curve(AUC)were evaluated based on the receiver operating characteristics(ROC)curve and these scoring systems were compared prospectively.Results:Of the 50 cases,14 were graded as severe acute pancreatitis.Pancreatic necrosis was present in 15 patients,while 14 developed persistent organ failure and 14 needed intensive care unit(ICU)admission.The AUC for modified CTSI was consistently the highest for predicting severe acute pancreatitis(0.919),pancreatic necrosis(0.993),organ failure(0.893)and ICU admission(0.993).APACHE II was the second most accurate in predicting severe acute pancreatitis(AUC 0.834)and organ failure(0.831).APACHE II had a high sensitivity for predicting pancreatic necrosis(93.33%),organ failure(92.86%)and ICU admission(92.31%),and also had a high negative predictive value for predicting pancreatic necrosis(96.15%),organ failure(96.15%)and ICU admission(95.83%).Conclusion:APACHE II is a useful prognostic scoring system for predicting the severity of acute pancreatitis and can be a crucial aid in determining the group of patients that have a high chance of need for tertiary care during the course of their illness and therefore need early resuscitation and prompt referral,especially in resource-limited developing countries.
文摘音频分类是音频信号处理中一项重要的预处理工作。该文描述了一种基于能量的分类方法,将音频信号分为语音和音乐2种类型。分类的过程分为3个阶段,首先计算优化低能量率MLER(modified low energy ratio)作为特征,然后利用初级分类器得到初步分类的结果,最后利用音频类别的前后相关性,使用上下文分类器修正初始分类得到最终分类的结果。该文重点对MLER中参数的合理选取范围进行了讨论,并对传统的初始分类器作了改进,用非参数分类器和参数分类器代替原有的Bayes硬判决的方法,避免了由于门限选择不当所带来的分类错误。实验表明,使用参数分类器时,对纯语音和纯音乐分类效果很好,正确率达99%以上。
