Comparative Study of Discretization Zero Dynamics Behaviors in Two Multirate Cases

Cheng Zeng,Shan Liang 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.4

It is well known that the existence of unstable zero dynamics is recognized as a major barrier in many control systems. When the usual digital control with zero-order hold (ZOH) or fractionalorder hold (FROH) input is used, unstable zero dynamics inevitably appear in the discrete-time model even though the continuous-time system with relative degree more than two is of minimum phase. This paper investigates the zero dynamics, as the sampling period tends to zero, of sampled-data models composed of a generalized sample hold function (GSHF), a continuous-time nonlinear plant and a sampler in cascade. More precisely, we show how an approximate sampled-data model can be obtained for nonlinear systems with two special GSHF cases such that sampled zero dynamics of the resulting model can be arbitrarily placed. Further, two GSHFs with appropriate parameters provide nonlinear zero dynamics as stable as possible, or with improved stability properties even when unstable, for a given continuous-time plant. It is also shown that the intersample behavior arising from the multirate input can be localised by appropriately selecting the design parameters based on the stability condition of the zero dynamics. The results presented here generalize well-known ideas from the linear to nonlinear cases.

Improving the Stability Behavior of Limiting Zeros for Multivariable Systems Based on Multirate Sampling

Cheng Zeng,Shan Liang,Shuwen Xiang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

It is well-known that existence of unstable sampling zeros is recognized as a major barrier in many control problems, and stability of sampling zeros, in general, depends on the type of hold circuit used to generate the continuous-time system input. This paper is concerned with stability of limiting zeros, as the sampling period tends to zero, of multivariable sampled-data models composed of a generalized sample hold function (GSHF), a continuous-time plant with the relative degrees being two and three, and a sampler in cascade. In particular, the main focus of the paper is how to preserve the stability of limiting zeros when at least one of the relative degrees of a multivariable system is more than two. In this case, the asymptotic properties of the limiting zeros on the basis of normal form representation of continuous-time systems are analyzed and approximate expressions for their stability are discussed as power series expansions with respect to a sufficiently small sampling period. More importantly, unstable sampling zeros of the sampled-data models mentioned above can be avoided successfully through the contribution of this paper, whereas a zero-order hold (ZOH) or a fractional-order hold (FROH) fails to do so. It is a further extension of previous results for single-input single-output cases to multivariable systems.

FASHION BLOGS: EFFECTS OF BLOGGING MOTIVATION AND SOCIAL CAPITALON ATTITUDE AND BLOG ENGAGEMENT

Xin Zeng,Jiyoung Kim,Kiseol Yang,Hwa-Ping Cheng 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

While it was found that consumers’ experience on purchase intention is significantly affected by greater involvement in blogging (Hsu & Tsou, 2011), not many fashion companies use blogs to improve online consumption and relationship with their employee or customer (Fieseler & Fleck, 2013). Further, despite the growing significance of blog communication, there is a lack of understanding for the impact of accumulation of social capital in the blogosphere on the consumers’ attitude and engagement in previous research. This study is designed to address this gap, and particularly the role of three dimensions of social capital (i.e., structural, relational, and cognitive) in understanding blog user’s attitude and engagement. The purpose of this study is to investigate 1) the effect of blog user’s motivation (i.e., perceived usefulness, perceived ease of use, reputation, altruism, enjoyment, community identification) on their level of social capital within the blog 2) the influence of structural social capital and cognitive social on user’s relational social capital and 3) the impact of relational social capital on blog user’s attitude and engagement. Data was collected through a marketing research firm utilizing online survey method. With 530 usable data, the results of this study indicated enjoyment have positive significant effect on structural social capital while community identification have negative significant effect on structural social capital. For the effect of blogging motivation on cognitive social capital, the result showed positive significant effect of perceived usefulness, altruism and community identification on cognitive social capital Further, structural social capital does not have relationship with relational social capital while cognitive social capital has significant effect on relational social capital. The results also indicated that the relational social capital has influence on blogging attitude, which in turn has strong positive relationship with blogging engagement. The findings of this study contribute some useful knowledge about fashion blog and the relationships of the three social capital dimensions to the literature. Also, this study not only provides theoretical insight into understanding the influence of fashion blog user’s motivation on blogging behavior and satisfaction of needs of belong, it also exposes the influence of relationships building in blog community on user’s blogging attitude and engagement. Previous studies focused more on social influence on knowledge sharing motivation, and most of the researchers paid attention to the interaction of cognitive social capital and relational capital. This study employs the knowledge sharing motivation findings of previous studies, and it uses the effective motivation factors to test if they have the same impacts on people’s blogging behavior.

Processing, digestion property and structure characterization of slowly digestible gorgon nut starch

Jia-cheng Zeng,Pin-Jian Xiao,Li-Juan Ling,Li Zhang,Dao-Bang Tang,Qing-Feng Zhang,Jiguang Chen,Jing-En Li,Zhongping Yin 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.1

Slowly digestible gorgon nut starch (GN-SDS) was prepared by heating–cooling treatment (HCT), meanwhile its morphological and structural features were characterized in detail by SEM, DSC, XRD and IR detection. The optimized parameters of GN-SDS processing were as following: starch milk (20%) was heated at 100 °C for 20 min, and then cooled under 4 °C for 24 h. Under the optimized parameters, the SDS content increased from 20.49 to 61.74%. GN-SDS showed typical SDS characteristics in in vivo digestion with a low postprandial blood glucose. SEM images suggested that GN-S particles changed from uniform regular polyhedron with smooth surface to irregular gravel-like particles with coarse surface and obvious layered structure inside after HCT. The results of SEM, DSC, XRD and IR determination indicated that HCT changed the granule morphology, interior structure, gelatinization temperature and crystal type (A to B-type) of GN-S, and therefore made it hard to be digested accordingly.

Effects of lycopene on number and function of human peripheral blood endothelial progenitor cells cultivated with high glucose

Yao-Chi Zeng,Gui-Ping Mu,Shu-Fen Huang,Xue-Hui Zeng,Hong Cheng,Zhong-Xin Li 한국영양학회 2014 Nutrition Research and Practice Vol.8 No.4

BACKGROUND/OBJECTIVES: The objectives of this study were to investigate the effects of lycopene on the migration, adhesion, tube formation capacity, and p38 mitogen-activated protein kinase (p38 MAPK) activity of endothelial progenitor cells (EPCs) cultivated with high glucose (HG) and as well as explore the mechanism behind the protective effects of lycopene on peripheral blood EPCs. MATERIALS/METHODS: Mononuclear cells were isolated from human peripheral blood by Ficoll density gradient centrifugation. EPCs were identified after induction of cellular differentiation. Third generation EPCs were incubated with HG (33 mmol/L) or 10, 30, and 50 μg/mL of lycopene plus HG. MTT assay and flow cytometry were performed to assess proliferation and apoptosis of EPCs. EPC migration was assessed by MTT assay with a modified boyden chamber. Adhesion assay was performed by replating EPCs on fibronectin-coated dishes, after which adherent cells were counted. In vitro vasculogenesis activity was assayed by Madrigal network formation assay. Western blotting was performed to analyze protein expression of both phosphorylated and non-phosphorylated p38 MAPK. RESULTS: The proliferation, migration, adhesion, and in vitro vasculogenesis capacity of EPCs treated with 10, 30, and 50 μg/mL of lycopene plus HG were all significantly higher comapred to the HG group (P < 0.05). Rates of apoptosis were also significantly lower than that of the HG group. Moreover, lycopene blocked phosphorylation of p38 MAPK in EPCs (P < 0.05). To confirm the causal relationship between MAPK inhibition and the protective effects of lycopene against HG-induced cellular injury, we treated cells with SB203580, a phosphorylation inhibitor. The inhibitor significantly inhibited HG-induced EPC injury. CONCLUSIONS: Lycopene promotes proliferation, migration, adhesion, and in vitro vasculogenesis capacity as well as reduces apoptosis of EPCs. Further, the underlying molecular mechanism of the protective effects of lycopene against HG-induced EPC injury may involve the p38 MAPK signal transduction pathway. Specifically, lycopene was shown to inhibit HG-induced EPC injury by inhibiting p38 MAPKs.

Subspace Identification for Fractional Order Hammerstein Systems Based on Instrumental Variables

Zeng Liao,Zhuting Zhu,Shu Liang,Cheng Peng,Yong Wang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.5

This paper focuses on time-domain identification issues of multi-input multi-output (MIMO) fractional order Hammerstein systems which are the extension of traditional Hammerstein type models by allowing linear part to be fractional order systems. The principal component analysis (PCA) method in subspace family is extended to identify coefficient matrixes of fractional order systems. Singular value decomposition (SVD) is utilized to estimate the unknown parameters of nonlinear part of system directly. A proper instrumental variable is chosen to eliminate the bias of identification results. Numerical simulation validates the proposed method.

A double integral characterization of a Bergman type space and its M\"obius invariant subspace

Cheng Yuan,Hong-Gang Zeng 대한수학회 2019 대한수학회보 Vol.56 No.6

This paper shows that if $1<p<\infty$, $\alpha\ge-n-2$, $\alpha>-1-\frac{p}{2} $ and $f$ is holomorphic on the unit ball $\bbn$, then $$\ibn |Rf(z)|^p(1-|z|^2)^{p+\alpha} \rd v_\alpha(z)<\infty$$ if and only if $$\ibn\ibn\frac{|f(z)-f(w)|^p}{|1-\langle z,w\rangle|^{n+1+s+t-\alpha}} (1-|w|^2)^s(1-|z|^2)^t \rd v(z)\rd v(w)<\infty,$$ where $s,t>-1$ with $\min(s,t)>\alpha $.

Investigation of flow-regime characteristics in a sloshing pool with mixed-size solid particles

Cheng, Songbai,Jin, Wenhui,Qin, Yitong,Zeng, Xiangchu,Wen, Junlang Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.5

To ascertain the characteristics of pool sloshing behavior that might be encountered during a core disruptive accident of sodium-cooled fast reactors, in our earlier work several series of experiments were conducted under various scenarios including the condition with mono-sized solid particles. It is found that under the particle-bed condition, three typical flow regimes (namely the bubble-impulsion dominant regime, the transitional regime and the bed-inertia dominant regime) could be identified and a flow-regime model (base model) has been even successfully established to estimate the regime transition. In this study, aimed to further understand this behavior at more realistic particle-bed conditions, a series of simulated experiments is newly carried out using mixed-size particles. Through analyses, it is verified that for present scenario, by applying the area mean diameter, our previously-developed base model can provide the most appropriate predictive results among the various effective diameters. To predict the regime transition with a form of extension scheme, a correction factor which is based on the volume-mean diameter and the degree of convergence in particle-size distribution is suggested and validated. The conducted analyses in this work also indicate that under certain conditions, the potential separation between different particle components might exist during the sloshing process.

Visualization of Peripheral Pulmonary Artery Red Thrombi Utilizing Optical Coherence Tomography

Cheng Hong,Wei Wang,Nan-shan Zhong,Guang-qiao Zeng,Nuo-fu Zhang 대한영상의학회 2013 Korean Journal of Radiology Vol.14 No.5

Optical coherence tomography (OCT) is a new imaging technique capable of obtaining high-resolution intravascular images and has been used in interventional cardiology. However, an application of OCT in pulmonary arteries had seldom been documented. In this case, OCT imaging is performed in peripheral pulmonary arteries and shows mural red thrombi. Subsequently, the red thrombi are aspirated and confirmed by a histological examination. These findings suggest that OCT may be a useful tool to depict peripheral pulmonary artery thrombi.

Single-Phase Virtual Synchronous Generator for Distributed Energy Resources Integration

Zeng, Zheng,Cheng, Chong,Tang, Shengqing,Yang, Huan,Zhao, Rongxiang Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.3

Virtual synchronous generator (VSG) in single-phase to interface distributed renewable energy resources is investigated in this paper. Mathematical models and numerical analysis are utilized to illustrate the features of the VSG. Enhanced control strategy is presented to ensure the performance of the VSG. Besides, a second order generalized integer (SOGI) is employed to calculate the instantaneous output power of the VSG in virtual ${\alpha}{\beta}$ frame. By the means of a phase-locked loop based scheme, the VSG can seamlessly transform between islanded and grid-tied modes, which can meet the requirements of micro-grid. At last, the validation and the proposed approach are verified by the simulated results using PSCAD/EMTDC.