资源类型

期刊论文 28

年份

2022 4

2021 3

2020 2

2019 1

2018 2

2017 3

2015 5

2014 2

2012 1

2009 1

2003 1

2001 1

2000 1

展开 ︾

关键词

P 1

S-N曲线 1

X 1

X'>存在定理 1

中央加密系统 1

人工智能 1

以人为本的管理系统 1

免疫学 1

全球标准方法 1

决策判定定理 1

决策去余定理 1

决策模型 1

决策识别定理 1

判据 1

双枝模糊决策 1

四元数傅里叶变换；四元数线性正则变换；采样定理；部分和总体四元数希尔伯特变换；部分和总体广义四元数希尔伯特变换；截断误差 1

复发 1

多齿加密-解密算法 1

大数据调度 1

展开 ︾

检索范围：

排序： 展示方式：

A reversibility-gain model for integer Karhunen-Loève transform design in video coding

Xing-guo ZHU,Lu YU

《信息与电子工程前沿（英文）》 2015年 第16卷 第10期   页码 883-891 doi: 10.1631/FITEE.1500071

摘要： Karhunen-Loève transform (KLT) is the optimal transform that minimizes distortion at a given bit allocation for Gaussian source. As a KLT matrix usually contains non-integers, integer-KLT design is a classical problem. In this paper, a joint reversibility-gain (R-G) model is proposed for integer-KLT design in video coding. Specifically, the ‘reversibility’ is modeled according to distortion analysis in using forward and inverse integer transform without quantization. It not only measures how invertible a transform is, but also bounds the distortion introduced by the non-orthonormal integer transform process. The ‘gain’ means transform coding gain (TCG), which is a widely used criterion for transform design in video coding. Since KLT maximizes the TCG under some assumptions, here we define the TCG loss ratio (LR) to measure how much coding gain an integer-KLT loses when compared with the original KLT. Thus, the R-G model can be explained as follows: subject to a certain TCG LR, an integer-KLT with the best reversibility is the optimal integer transform for a given non-integer-KLT. Experimental results show that the R-G model can guide the design of integer-KLTs with good performance.

关键词： Integer transform     Karhunen-Loè     ve transform (KLT)     Integer-KLT     Transform coding     Video coding    

HTML PDF 收藏

Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling mode shapes: A semi-analytical non-intrusive approach

《结构与土木工程前沿（英文）》   页码 179-190 doi: 10.1007/s11709-022-0888-z

摘要： In this study, the mechanical properties of the composite plate were considered Gaussian random fields and their effects on the buckling load and corresponding mode shapes were studied by developing a semi-analytical non-intrusive approach. The random fields were decomposed by the Karhunen−Loève method. The strains were defined based on the assumptions of the first-order and higher-order shear-deformation theories. Stochastic equations of motion were extracted using Euler–Lagrange equations. The probabilistic response space was obtained by employing the non-intrusive polynomial chaos method. Finally, the effect of spatially varying stochastic properties on the critical load of the plate and the irregularity of buckling mode shapes and their sequences were studied for the first time. Our findings showed that different shear deformation plate theories could significantly influence the reliability of thicker plates under compressive loading. It is suggested that a linear relationship exists between the mechanical properties’ variation coefficient and critical loads’ variation coefficient. Also, in modeling the plate properties as random fields, a significant stochastic irregularity is obtained in buckling mode shapes, which is crucial in practical applications.

关键词： uncertain composite plate     stochastic assume mode method     Karhunen−Loève theorem     polynomial chaos approach     plate buckling     irregularity in buckling mode shapes    

HTML PDF 收藏

双枝模糊决策与决策识别问题

史开泉,李歧强

《中国工程科学》 2001年 第3卷 第1期   页码 71-77

摘要：

文章提出具有中性域X*(X*≠{x})X的上的双枝模糊决策的概念和决策优化分析模型、决策判定定理、决策识别定理、决策去余定理和决策因素域X上的挖洞原理。双枝模糊决策具有下列特征：决策结论的双向依赖特性，决策结论的叠加合成特性，决策结论的枝-分离特性，决策结论的枝-退化特性，决策结论的非失误特性。研究结果得到了应用。

关键词： 双枝模糊决策     决策模型     决策判定定理     决策识别定理     决策去余定理     挖洞原理    

HTML PDF 收藏

Advancements in non-starch polysaccharides research for frozen foods and microencapsulation of probiotics

Martin LO,

《化学科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 413-426 doi: 10.1007/s11705-009-0254-x

摘要： Conventionally used in the food industry as stabilizing, thickening, gelling, and suspending or dispersing agents, non-starch polysaccharides such as xanthan gum are known to improve the texture of certain frozen products. Another polysaccharide that has received significant attention in recent years is chitosan, a natural biopolymer derived from chitin. In the wake of growing interest in finding ideal encapsulating agents for probiotics, non-starch polysaccharides have been investigated. Scattered research can be found on the effect of each individual polysaccharide, but there remains a void in the literature in terms of closely comparing the characteristics of non-starch polysaccharides for these applications, especially when more than one biopolymer is employed. A good understanding of the tools capable of elucidating the underlying mechanisms involved is essential in ushering further development of their applications. Therefore, it is this review’s intention to focus on the selection criteria of non-starch polysaccharides based on their rheological properties, resistance to harsh conditions, and ability to improve sensory quality. A variety of critical tools is also carefully examined with respect to the attainable information crucial to frozen food and microencapsulation applications.

关键词： development     literature     attainable information     biopolymer     capable    

HTML PDF 收藏

Decomposition of perfluorooctanoic acid by microwave-activated persulfate: Effects of temperature, pH, and chloride ions

Yuchi LEE, Shanglien LO, Jeff KUO, Chinghong HSIEH

《环境科学与工程前沿（英文）》 2012年 第6卷 第1期   页码 17-25 doi: 10.1007/s11783-011-0371-x

摘要： Microwave-hydrothermal treatment of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water with persulfate ( ) has been found effective. However, applications of this process to effectively remediate PFOA pollution require a better understanding on free-radical scavenging reactions that also take place. The objectives of this study were to investigate the effects of pH (pH= 2.5, 6.6, 8.8, and 10.5), chloride concentrations (0.01–0.15 mol·L ), and temperature (60°C, 90°C, and 130°C) on persulfate oxidation of PFOA under microwave irradiation. Maximum PFOA degradation occurred at pH 2.5, while little or no degradation at pH 10.5. Lowering system pH resulted in an increase in PFOA degradation rate. Both high pH and chloride concentrations would result in more scavenging of sulfate free radicals and slow down PFOA degradation. When chloride concentrations were less than 0.04 mol·L at 90°C and 0.06 mol·L at 60°C, presence of chloride ions had insignificant impacts on PFOA degradation. However, beyond these concentration levels, PFOA degradation rates reduced significantly with an increase in chloride concentrations, especially under the higher temperature.

关键词： microwave     perfluorooctanoic acid     pH     persulfate     chloride ions     perfluorocarboxylic acids    

HTML PDF 收藏

Treatment, residual chlorine and season as factors affecting variability of trihalomethanes in small drinking water systems

Roberta DYCK,Geneviève COOL,Manuel RODRIGUEZ,Rehan SADIQ

《环境科学与工程前沿（英文）》 2015年 第9卷 第1期   页码 171-179 doi: 10.1007/s11783-014-0750-1

摘要： Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate seasonal variability of water quality in municipal small water systems (<3000 residents) supplied by surface waters. Residual chlorine and trihalomethanes (THM) were measured over seven years (2003–2009). Comparisons are made within each system over time, as well as between systems according to the type of their treatment technologies. THM concentrations are generally higher in the summer and autumn. The seasonal variability was generally more pronounced in systems using chlorination plus additional treatment. Chloroform, total THM (TTHM) and residual chlorine concentrations were generally lower in systems using chlorination plus additional treatment. Conversely, brominated THM concentrations were higher in systems using additional treatment. Residual chlorine was highest in the winter and lowest in the spring and summer. Seasonal variations were most pronounced for residual chlorine in systems with additional treatment. There was generally poor correlation between THM concentrations and concentrations of residual chlorine. Further study with these data will be beneficial in finding determinants and indicators for both quantity and variability of disinfection byproducts and other water quality parameters.

关键词： drinking water     residual chlorine     seasonal variability     small municipal systems     treatment technologies     trihalomethanes    

HTML PDF 收藏

Classical state feedback controller for nonlinear systems using mean value theorem: closed loop-FOC of

Abrar ALLAG,Abdelhamid BENAKCHA,Meriem ALLAG,Ismail ZEIN,Mohamed Yacine AYAD

《能源前沿（英文）》 2015年 第9卷 第4期   页码 413-425 doi: 10.1007/s11708-015-0379-1

摘要： The problem of state feedback controllers for a class of Takagi-Sugeno (T-S) Lipschitz nonlinear systems is investigated. A simple systematic and useful synthesis method is proposed based on the use of the differential mean value theorem (DMVT) and convex theory. The proposed design approach is based on the mean value theorem (MVT) to express the nonlinear error dynamics as a convex combination of known matrices with time varying coefficients as linear parameter varying (LPV) systems. Using the Lyapunov theory, stability conditions are obtained and expressed in terms of linear matrix inequalities (LMIs). The controller gains are then obtained by solving linear matrix inequalities. The effectiveness of the proposed approach for closed loop-field oriented control (CL-FOC) of permanent magnet synchronous machine (PMSM) drives is demonstrated through an illustrative simulation for the proof of these approaches. Furthermore, an extension for controller design with parameter uncertainties and perturbation performance is discussed.

关键词： Takagi-Sugeno (T-S) fuzzy systems     sector nonlinearity     nonlinear controller     linear matrix inequality (LMI) approach     differential mean value theorem (DMVT)     field oriented control (FOC)     linear parameter varying (LPV)    

HTML PDF 收藏

Robust public-private partnerships for joint railway and property development

LO, Yue HUAI

《工程管理前沿（英文）》 2017年 第4卷 第4期   页码 437-450 doi: 10.15302/J-FEM-2017068

摘要： The involvement of the private sector in the construction or operation of an infrastructure project may enhance the financial viability of projects, which facilitates the formation of public-private partnership (PPP) for project delivery. PPP exploits the strength of the private sector by shifting certain project risks from the public party to the private sector who can efficiently manage certain risks. In joint railway and housing development, the approach of bundling railway and housing development (R&HD) allows cross-subsidization between immense railway construction cost and profitable housing rental revenue. This approach also provides flexibility in incorporating PPP models by distributing railway and housing revenues and costs and their inherent risks properly to the public and private sectors. Ng and Lo (2015a) developed an evaluation framework for joint railway and property development, which evaluates PPPs based on financial and construction criteria for selecting the best suitable PPP for a particular project. This study, which is based on the framework in Ng and Lo (2015a), aims to examine the robustness of various PPP configurations. This study analyzes the effects of PPP configurations on stakeholders’ risks and returns under population or demand growth and railway construction cost uncertainties. The eventual outcome of particular PPP configurations is also examined. This study also seeks to answer the following questions: How would optimal configuration change under highly volatile population and railway construction cost? Are there PPP configurations that are robust to these uncertainties and those that are sensitive to a particular uncertainty? This understanding is critical for managing risks and facilitating the formation of appropriate PPP for R&HD.

关键词： public-private partnership     BFOOD     housing and railway development    

HTML PDF 收藏

水机材料的抗磨蚀性判据研究

王飚,王宇栋,张自华,叶献国

《中国工程科学》 2003年 第5卷 第7期   页码 58-61

摘要：

为了证实水机材料的抗磨蚀和抗空蚀性能与材料的常规宏观性能之间的相依关系，选取4种具代表性的材料（碳化钨涂层、NiCr合金涂层、硼不锈钢涂层和钛），进行空蚀和磨蚀试验，并测试了它们的硬度和抗腐蚀性。试验结果表明，材料的空蚀和磨蚀抗力与硬度和抗腐蚀性有着紧密的相依关系：高硬度是抗磨蚀性优的第一判据，较强的抗腐蚀性是第二判据；高抗腐蚀性是抗空蚀性优的第一判据，较高的硬度是第二判据。

关键词： 水机材料     磨蚀     判据    

HTML PDF 收藏

Quantifying and mapping spatial variability of Shanghai household carbon footprints

Shangguang YANG,Chunlan WANG,Kevin LO,Mark WANG,Lin LIU

《能源前沿（英文）》 2015年 第9卷 第1期   页码 115-124 doi: 10.1007/s11708-015-0348-8

摘要： Understanding the spatial variability of household carbon emissions is necessary for formulating sustainable and low-carbon energy policy. However, data on household carbon emissions is limited in China, the world’s largest greenhouse gases emitter. This study quantifies and maps household carbon emissions in Shanghai using a city-wide household survey. The findings reveal substantial spatial variability in household carbon emissions, especially in transport-related emissions. Low emission clusters are founded in Hongkou, Xuhui, Luwan, Jinshan, and Fengxian. High emission clusters are located in Jiading and Pudong. Overall, the spatial pattern of household carbon emissions in Shanghai is donut-shaped: lowest in the urban core, increasing in the surrounding suburban areas, and declining again in the urban fringe and rural regions. The household emissions are correlated with a number of housing and socioeconomic factors, including car ownership, type of dwelling, size of dwelling, age of dwelling, and income. The findings underscore the importance of a localized approach to low-carbon policy-making and implementation.

关键词： household carbon emissions     spatial variability     energy policy     Shanghai     China    

HTML PDF 收藏

Application of consistent geometric decomposition theorem to dynamic finite element of 3D composite beam

Iman FATTAHI, Hamid Reza MIRDAMADI, Hamid ABDOLLAHI

《结构与土木工程前沿（英文）》 2020年 第14卷 第3期   页码 675-689 doi: 10.1007/s11709-020-0625-4

摘要： Analyzing static and dynamic problems including composite structures has been of high significance in research efforts and industrial applications. In this article, equivalent single layer approach is utilized for dynamic finite element procedures of 3D composite beam as the building block of numerous composite structures. In this model, both displacement and strain fields are decomposed into cross-sectional and longitudinal components, called consistent geometric decomposition theorem. Then, the model is discretized using finite element procedures. Two local coordinate systems and a global one are defined to decouple mechanical degrees of freedom. Furthermore, from the viewpoint of consistent geometric decomposition theorem, the transformation and element mass matrices for those systems are introduced here for the first time. The same decomposition idea can be used for developing element stiffness matrix. Finally, comprehensive validations are conducted for the theory against experimental and numerical results in two case studies and for various conditions.

关键词： composite beam     dynamic finite element     degrees of freedom coupling     experimental validation     numerical validation    

HTML PDF 收藏

Molecular dynamics simulations of initial Pd and PdO nanocluster growth in a magnetron gas aggregation source

Pascal Brault, William Chamorro-Coral, Sotheara Chuon, Amaël Caillard, Jean-Marc Bauchire, Stève Baranton

《化学科学与工程前沿（英文）》 2019年 第13卷 第2期   页码 324-329 doi: 10.1007/s11705-019-1792-5

摘要： Molecular dynamics simulations are carried out for describing growth of Pd and PdO nanoclusters using the ReaxFF force field. The resulting nanocluster structures are successfully compared to those of nanoclusters experimentally grown in a gas aggregation source. The PdO structure is quasi-crystalline as revealed by high resolution transmission microscope analysis for experimental PdO nanoclusters. The role of the nanocluster temperature in the molecular dynamics simulated growth is highlighted.

关键词： molecular dynamics     cluster growth     plasma sputtering     nanocatalyst    

HTML PDF 收藏

Ambient air pollution and lung disease in China: health effects, study design approaches and future research

null

《医学前沿（英文）》 2015年 第9卷 第3期   页码 392-400 doi: 10.1007/s11684-015-0397-8

摘要：

Ambient air pollution in China has worsened following dramatic increases in industrialization, automobile use and energy consumption. Particularly bothersome is the increase in the PM2.5 fraction of pollutants. This fraction has been associated with increasing rates of cardio-respiratory disease in China and elsewhere. Ambient pollutant levels have been described in many of China’s cities and are comparable to previous levels in southern California. Lung cancer mortality in China has increased since the 1970s and has been higher in men and in urban areas, the exact explanation for which has not been determined. The estimation of individual risk for Chinese citizens living in areas of air pollution will require further research. Occupational cohort and case-control designs each have unique attributes that could make them helpful to use in this setting. Other important future research considerations include detailed exposure assessment and the possible use of biomarkers as a means to better understand and manage the threat posed by air pollution in China.

关键词： air pollution     PM2.5     lung disease     study design     epidemiology    

HTML PDF 收藏

生成锁P<G,X,X'>和它的中央加密系统

史开泉,陈泽雄

《中国工程科学》 2000年 第2卷 第2期   页码 41-46

摘要：

利用数据生成技术，提出生成锁P <G ,X, X´>的概念和由P <G ,X, X´>构成的中央加密系统。这些系统是：生成锁P <G ,X, X´>与单齿中央加密系统，生成锁P <G ,X, X´>与多齿中央加密系统。给出单齿加密-解密算法，多齿加密-解密算法，多齿静态加密-解密算法，多齿动态加密-解密算法，中央加密系统的结构特性。研究指出：任意两个秘密通讯的双方A和B，它们各自选择无规则分布的正整数集合XA={x1，x2，…，xn}，XB={x1，x2，…，xm}，m,n≥4，XA≠XB，利用P <G ,X, X´>完成双方之间的秘密通讯。研究结果表明，所提出的方法具有良好的应用性，安全性。

关键词： 生成锁     中央加密系统     多齿加密-解密算法     P    X     X'>存在定理     数位签章唯一性定理    

HTML PDF 收藏

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第4期   页码 344-353 doi: 10.1007/s11465-014-0320-z

摘要：

This paper is a detailed exploration of instantaneous poles for a class of two-degree-of-freedom (two-DOF) spherical mechanisms (SMs) with seven links or bars. For two-DOF SMs, the secondary instantaneous poles (the ones which cannot be found by direct inspection) must lie on the specified great circles. For many of these mechanisms, however, some of these great circles cannot be obtained by a direct application of Aronhold-Kennedy theorem. This paper presents geometrical and analytical techniques to locate these unknown great circles for three topologies of seven-bar two-DOF SMs.

关键词： spherical mechanisms     instantaneous poles     Aronhold-Kennedy theorem     great circles     pencil of meridian    

HTML PDF 收藏

标题 作者 时间 类型 操作

A reversibility-gain model for integer Karhunen-Loève transform design in video coding

Xing-guo ZHU,Lu YU

期刊论文

Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling mode shapes: A semi-analytical non-intrusive approach

期刊论文

双枝模糊决策与决策识别问题

史开泉,李歧强

期刊论文

Advancements in non-starch polysaccharides research for frozen foods and microencapsulation of probiotics

Martin LO,

期刊论文

Decomposition of perfluorooctanoic acid by microwave-activated persulfate: Effects of temperature, pH, and chloride ions

Yuchi LEE, Shanglien LO, Jeff KUO, Chinghong HSIEH

期刊论文

Treatment, residual chlorine and season as factors affecting variability of trihalomethanes in small drinking water systems

Roberta DYCK,Geneviève COOL,Manuel RODRIGUEZ,Rehan SADIQ

期刊论文

Classical state feedback controller for nonlinear systems using mean value theorem: closed loop-FOC of

Abrar ALLAG,Abdelhamid BENAKCHA,Meriem ALLAG,Ismail ZEIN,Mohamed Yacine AYAD

期刊论文

Robust public-private partnerships for joint railway and property development

LO, Yue HUAI

期刊论文

水机材料的抗磨蚀性判据研究

王飚,王宇栋,张自华,叶献国

期刊论文

Quantifying and mapping spatial variability of Shanghai household carbon footprints

Shangguang YANG,Chunlan WANG,Kevin LO,Mark WANG,Lin LIU

期刊论文

Application of consistent geometric decomposition theorem to dynamic finite element of 3D composite beam

Iman FATTAHI, Hamid Reza MIRDAMADI, Hamid ABDOLLAHI

期刊论文

Molecular dynamics simulations of initial Pd and PdO nanocluster growth in a magnetron gas aggregation source

Pascal Brault, William Chamorro-Coral, Sotheara Chuon, Amaël Caillard, Jean-Marc Bauchire, Stève Baranton

期刊论文

Ambient air pollution and lung disease in China: health effects, study design approaches and future research

null

期刊论文

生成锁P<G,X,X'>和它的中央加密系统

史开泉,陈泽雄

期刊论文

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文