Advances in solution of classical generalized eigenvalue problem

Chen, P.,Sun, S.L.,Zhao, Q.C.,Gong, Y.C.,Chen, Y.Q.,Yuan, M.W. Techno-Press 2008 Interaction and multiscale mechanics Vol.1 No.2

Owing to the growing size of the eigenvalue problem and the growing number of eigenvalues desired, solution methods of iterative nature are becoming more popular than ever, which however suffer from low efficiency and lack of proper convergence criteria. In this paper, three efficient iterative eigenvalue algorithms are considered, i.e., subspace iteration method, iterative Ritz vector method and iterative Lanczos method based on the cell sparse fast solver and loop-unrolling. They are examined under the mode error criterion, i.e., the ratio of the out-of-balance nodal forces and the maximum elastic nodal point forces. Averagely speaking, the iterative Ritz vector method is the most efficient one among the three. Based on the mode error convergence criteria, the eigenvalue solvers are shown to be more stable than those based on eigenvalues only. Compared with ANSYS's subspace iteration and block Lanczos approaches, the subspace iteration presented here appears to be more efficient, while the Lanczos approach has roughly equal efficiency. The methods proposed are robust and efficient. Large size tests show that the improvement in terms of CPU time and storage is tremendous. Also reported is an aggressive shifting technique for the subspace iteration method, based on the mode error convergence criteria. A backward technique is introduced when the shift is not located in the right region. The efficiency of such a technique was demonstrated in the numerical tests.

BMB Reports : Heat shock protein 90β inhibits apoptosis of intestinal epithelial cells induced by hypoxia through stabilizing phosphorylated Akt

( Shuai Zhang ),( Yong Sun ),( Zhi Qiang Yuan ),( Ying Li ),( Xiao Lu Li ),( Zhen Yu Gong ),( Yi Zhi Peng ) 생화학분자생물학회(구 한국생화학분자생물학회) 2013 BMB Reports Vol.46 No.1

Intestinal epithelial cell (IEC) apoptosis induced by hypoxia compromise intestinal epithelium barrier function. Both Akt and Hsp90 have cytoprotective function. However, the specific role of Akt and Hsp90β in IEC apoptosis induced by hypoxia has not been explored. We confirmed that hypoxia-induced apoptosis was reduced by Hsp90β overexpression but enhanced by decreasing Hsp90β expression. Hsp90β overexpression enhanced BAD phosphorylation and thus reduced mitochondrial release of cytochrome C. Reducing Hsp90β expression had opposite effects. The protective effect of Hsp90β against apoptosis was negated by LY294002, an Akt inhibitor. Further study showed that Akt phosphorylation was enhanced by Hsp90β, which was not due to the activation of upstream PI3K and PDK1 but because of stabilization of pAkt via direct interaction between Hsp90β and pAkt. These results demonstrate that Hsp90β may play a significant role in protecting IECs from hypoxia-induced apoptosis via stabilizing pAkt to phosphorylate BAD and reduce cytochrome C release. [BMB Reports 2013; 46(1): 47-52]

New criteria on finite-time stability of nonautonomous systems with delay and disturbance

Ya-Nan Li,Yuan-Gong Sun 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10

This paper is concerned with the problem of finite-time stability for nonautonomous systems subject to timevarying delay and disturbance. Based on the piecewise estimate of the time-varying system matrices, we establish a new explicit criterion in terms of multiple linear matrix inequalities guaranteeing that the state trajectory does not exceed a certain threshold over a pre-specified finite-time interval. The main result of this paper generalizes and improves some existing results in the literature, and can also be extended to the more general nonlinear case. Finally, a numerical example is worked out to illustrate the effectiveness of the proposed method.

Stability analysis of uncertain switched systems via delay partitioning

Wen-xiu Zhao,Yuan-Gong Sun 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10

In this paper, by using the delay partitioning approach, new stability criteria in terms of linear matrix inequalities are established for uncertain switched linear system with delay. It is shown that the given method allows less conservative upper bound of delay as the number of delay partitioning increases. Numerical examples are also given to illustrate the main results.

H<SUB>∞</SUB> Consensus for Heterogeneous Multi-agent Systems with Time-delay

Bei-Bei Wang,Yuan-Gong Sun 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10

In this paper, we consider the consensus and H∞ consensus problems of heterogeneous multi-agent systems composed of first-order and second-order integrator agents in directed networks with time-delay. Based on the graph theory and the reduced-order transformation, we first rewrite the heterogeneous multi-agent systems into the corresponding reduced-order systems. Then, we study the consensus of the heterogeneous multi-agent system with time-delay by using the linear matrix inequality method. As a result, sufficient conditions for consensus and H∞ consensus of heterogeneous multi-agent systems in terms of linear matrix inequalities are established. Finally, simulation results are provided to demonstrate the effectiveness of the main theoretical results.

Stability Analysis for Time-Varying Positive Linear Systems with Delays

Min-Min Zhao,Yuan-Gong Sun 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

This paper is focused on stability analysis for a class of time-varying positive linear systems with delays. Two kind of time-varying delays are taken into consideration. One is the time-varying state delay that can be unbounded. The other is the bounded distributed delay. By using a new method, a state-delay-independent and distribute-delay-dependent criterion for asymptotic stability of the system is established.

Effects of Allogeneic Blood Transfusion in Patients with Stage II Colon Cancer

Meng, Jin,Lu, Xiao-Bo,Tang, Yuan-Xin,Sun, Gong-Ping,Li, Xin,Yan, Yi-Fei,Liang, Gao-Feng,Ma, Si-Ping,Li, Xiao-Xia Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.1

The aim of the present study was to determine whether allogeneic red blood cell transfusions showed a deleterious effect and what might be preoperative risk factors for blood transfusion in patients with TNM stage II colon cancer. Total 470 patients who fulfilled inclusion criteria were selected for a further 10-year follow-up study. We found that there were statistical significance between non-transfused and transfused group in mortality (P=0.018), local recurrence (P=0.000) and distant metastasis (P=0.040). Local recurrence and distant metastasis between 1 to 3 units and more than 3 units group did not show any significant differences. There was no difference in survival rate between non-transfused and 1 to 3 units group (log rank=0.031, P=0.860). The difference between different blood transfusion volume in transfused patients was found (78.77% vs 63.83%, P=0.006). Meanwhile, the significant difference of survival rate was existed between non-transfused group and more than 3 units group (84.83% vs 63.83%, P=0.002 ). Univariate analysis showed the following 3 variables to be associated with an increased risk of allogeneic blood transfusions: preoperative CEA level (P<0.05), location of tumor (P<0.01) and diameter of tumor (P<0.01). Multivariate analysis revealed that location of tumor and diameter of tumor are two independent factors for requirement of perioperative transfusions. Therefore, allogeneic transfusion increase the postoperative tumor mortality, local recurrence and distant metastasis in patients with stage II colon cancer. The postoperative tumor mortality, local recurrence and distant metastasis were not associated with the blood transfusion volume. The blood transfusion volume was associated with the survival rate. Location of tumor and diameter of tumor were the independent preoperative risk factors for blood transfusion.

Characterization of clutch traits and egg production in six chicken breeds

Shi Lei,Li Yunlei,Isa Adam Mani,Ma Hui,Yuan Jingwei,Wang Panlin,Ge Pingzhuang,Gong Yanzhang,Chen Jilan,Sun Yanyan 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.6

Objective: The better understanding of laying pattern of birds is crucial for developing breed-specific proper breeding scheme and management. Methods: Daily egg production until 50 wk of age of six chicken breeds including one layer (White Leghorn, WL), three dual-purpose (Rhode Island Red, RIR; Columbian Plymouth Rock, CR; and Barred Plymouth Rock, BR), one synthetic dwarf (DY), and one indigenous (Beijing-You Chicken, BYC) were used to characterize their clutch traits and egg production. The age at first egg, egg number, average and maximum clutch length, pause length, and number of clutches and pauses were calculated accordingly. Results: The egg number and average clutch length in WL, RIR, CR, and BR were higher than those in DY and BYC (p<0.01). The numbers of clutches and pauses, and pause length in WL, RIR, CR, and BR were lower than those in DY and BYC (p<0.01). The coefficient variations of clutch length in WL, RIR, CR, and BR (57.66%, 66.49%, 64.22%, and 55.35%, respectively) were higher than DY (41.84%) and BYC (36.29%), while the coefficient variations of egg number in WL, RIR, CR, and BR (9.10%, 9.97%, 10.82%, and 9.92%) were lower than DY (15.84%) and BYC (16.85%). The clutch length was positively correlated with egg number (r = 0.51 to 0.66; p<0.01), but not correlated with age at first egg in all breeds. Conclusion: The six breeds showed significant different clutch and egg production traits. Due to the selection history, the high and median productive layer breeds had higher clutch length than those of the less productive indigenous BYC. The clutch length is a proper selection criterion for further progress in egg production. The age at first egg, which is independent of clutch traits, is especially encouraged to be improved by selection in the BYC breed.