Linear Optimal Estimation for Discrete-time and Continuous-time Systems with Multiple Measurement Delays

Na-Na Jin,Shuai Liu,Huan-Shui Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.3

In this paper, we investigate the linear optimal estimation problems of discrete-time and continuous-time systems with multiple state delays in measurements. For discrete-time systems, we obtain the linear optimal estimation of state by direct calculation of optimal gain in terms of the solution to a retarded Riccati-like difference equation instead of a group of Riccati difference equations. For continuous-time systems, we also obtain the analytical expression of linear optimal estimation without resorting to Riccati partial differential equations. All the Riccati equations are of the same dimension as the system to be estimated and the computational cost is much saved. Infinite horizon case is also studied by stability analysis. Kalman filter can be recovered from our result when delays disappear. A numerical example is provided to demonstrate the results.

Multi-switching adaptive synchronization of two fractional-order chaotic systems with different structure and different order

Shuai Song,Xiao-Na Song,Nimisha Pathak,Ines Tejado Balsera 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.4

In this work, we combine the active and adaptive control theories, and propose a novel synchronizationscheme for a class of fractional-order chaotic systems with different structure and different order. Based on the newversion of fractional-order Lyapunov stability theory, we design the adaptive controllers and updating laws of differentswitching. We use the fractional-order Lorenz chaotic system and the fractional-order Chen chaotic system asexamples to analyze the multi-switching synchronization process for fractional-order chaotic systems with differentstructures and different orders. Finally, numerical simulations are also given to illustrate the effectiveness and validationof the proposed method, and the model uncertainties and external disturbances are added to the consideredsystems to verify the robustness of the proposed controllers.

Effect of Laser Power on Tensile Performance of TA15 Laser-Welded Lock Bottom Joint

Na Qi,Xiaohong Zhan,Shuai Chen,Dan Chen,Shi He 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

Taking TA15 titanium alloy as the research object, laser welding experiments of are performed on the lock-bottom joints,and the microstructure and tensile performance of the joints are analyzed. The laser welding speed is constant and the laserpower is 1000 w, 1300 kw, 1600 kw respectively. The bottom weld width and the width of high temperature heat-affectedzone (HT-HAZ) increase significantly as laser power increase. The microstructure of the heat-affected zone (HAZ) is relativelycomplicated, mainly composed of secondary α, acicular α structure and β. The microstructure at the weld metal iscomprised of the martensite α′ and acicular α. The tensile strength, fracture morphology and chemical composition of thewelded joint are studied by tensile test, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS)analysis techniques. The results show that all the specimens fractured near the heat-affected zone, and the fracture is a ductilefracture in the shape of a dimple. The tensile strength of welded joint decreases with the increase of laser power. Whenthe laser power is 1.0 kw, 1.3 kw and 1.6 kw, the tensile strength is 723 MPa, 705 MPa and 695 MPa respectively, which is64.55%, 62.95% and 62.05% of the base material strength. EDS results show that Mo and V elements are the strengtheningelements, while the burning loss of Mo and V reduce the strength of the joint.

Assessing Abdominal Aortic Aneurysm Progression by Using Perivascular Adipose Tissue Attenuation on Computed Tomography Angiography

Zhang Shuai,Gu Hui,Chang Na,Li Sha,Xu Tianqi,Liu Menghan,Wang Ximing 대한영상의학회 2023 Korean Journal of Radiology Vol.24 No.10

Objective: Recent studies have highlighted the active and potential role of perivascular adipose tissue (PVAT) in atherosclerosis and aneurysm progression, respectively. This study explored the link between PVAT attenuation and abdominal aortic aneurysm (AAA) progression using computed tomography angiography (CTA). Materials and Methods: This multicenter retrospective study analyzed patients with AAA who underwent CTA at baseline and follow-up between March 2015 and July 2022. The following parameters were obtained: maximum diameter and total volume of the AAA, presence or absence of intraluminal thrombus (ILT), maximum diameter and volume of the ILT, and PVAT attenuation of the aortic aneurysm at baseline CTA. PVAT attenuation was divided into high (> -73.4 Hounsfield units [HU]) and low (≤ -73.4 HU). Patients who had or did not have AAA progression during the follow-up, defined as an increase in the aneurysm volume > 10 mL from baseline, were identified. Kaplan–Meier and multivariable Cox regression analyses were used to investigate the association between PVAT attenuation and AAA progression. Results: Our study included 167 participants (148 males; median age: 70.0 years; interquartile range: 63.0–76.0 years), of which 145 (86.8%) were diagnosed with AAA accompanied by ILT. Over a median period of 11.3 months (range: 6.0–85.0 months), AAA progression was observed in 67 patients (40.1%). Multivariable Cox regression analysis indicated that high baseline PVAT attenuation (adjusted hazard ratio [aHR] = 2.23; 95% confidence interval [CI], 1.16–4.32; P = 0.017) was independently associated with AAA progression. This association was demonstrated within the patients of AAA with ILT subcohort, where a high baseline PVAT attenuation (aHR = 2.23; 95% CI, 1.08–4.60; P = 0.030) was consistently independently associated with AAA progression. Conclusion: Elevated PVAT attenuation is independently associated with AAA progression, including patients of AAA with ILT, suggesting the potential of PVAT attenuation as a predictive imaging marker for AAA expansion.

Optimization of Grey Neural Network Model Based on Mind Evolutionary Algorithm

Zhang, Yong-Li(장영예),Na, Sang-Gyun(나상균),Wang, Bao-Shuai(왕바오슈아이) 한국산업경제학회 2017 산업경제연구 Vol.30 No.4

회색신경망모형은 제품의 주문 수량을 예측할 때 소 표본과 정보부족 등의 문제를 해결하는데 유용하게 사용할 수 있지만, 예측 시 무작위로 파라미터를 초기화하면 예측정확도가 낮아지는 단점이 있다. 따라서 본 연구에서는 전통적인 회색신경망모형의 단점을 보완하기 위해서 MEA(Mind Evolution Algorithm)를 적용한 최적화된 회색 신경망모형을 제시하였다. 본 연구 결과는 다음과 같다. 제품의 주문수량을 예측하기 위해서 MEA(Mind Evolution Algorithm)를 이용한 최적화된 회색신경망모형, PSO(Particle Swarm Optimization)를 이용한 최적화된 회색신경망모형, GA(Genetic Algorithm)을 이용한 최적화된 회색신경망모형, BP(Back Propagation)을 이용한 회색신경망모형에 대해 비교분석을 하였다. 분석결과를 보면, MEA(Mind Evolution Algorithm)를 이용한 최적화된 회색신경망모형의 예측 총오차 4457.6000, 평균루트오차 920.7372, 평균오차백분율 4.04%, 운영시간은 1.1509초로 분석되었다. 선행연구에서 제시한 가장 우수한 PSO(Particle Swarm Optimization)를 이용한 최적화된 회색 신경망모형 보다, MEA(Mind Evolution Algorithm)를 이용한 최적화된 회색신경망모형의 예측 총 오차가 16.12%, 평균루트오차 12.39%, 평균오차백분율 16.87%가 감소되어, 결과적으로 운영시간이 감소되면서 계산속도가 21.61%가 증가 되었다. 따라서 다른 지능알고리즘과 비교하면, MEA(Mind Evolution Algorithm)를 이용한 최적화된 회색신경망모형은 최고의 예측 정확도와 계산속도가 높다는 장점을 보유하고 있다. 따라서 기업에서 제품의 주문 수량을 예측할 때 소 표본과 정보부족 등의 문제가 발생할 경우, 최적화된 회색신경망모형을 이용하는 것이 필요하다. For the problem of randomized parameters and large error, the grey neural network model optimized by mind evolutionary algorithm(MEA-GNNM) was presented. The experiment results showed that the total error, root mean square error, mean percentage error, and running time of MEA-GNNM were 4457.6000, 920.7372, 4.04% and 1.1509 seconds; Compared with GA-GNNM, the total error, root mean square error and mean percentage error of MEA-GNNM had decreased by 16.12%, 12.39% and 16.87%, and the calculation speed increased by 21.61%. Compared with PSO-GNNM, the total error, root mean square error and mean percentage error of MEA-GNNM had decreased by 9.13%, 11.33% and 12.17%, but running time increased by 104.50%. The paper presents a new approach to optimize the parameters of grey neural network model, and also provides a new method having higher prediction accuracy for the time series prediction.

Curcumin derivative HBC induces autophagy through activating AMPK signal in A549 cancer cells

Guang-Zhou Zhou,Gang-Chun Sun,Shuai-Na Zhang 대한독성 유전단백체 학회 2015 Molecular & cellular toxicology Vol.11 No.1

Curcumin exhibits growth-suppressive activity against a variety of cancer cells, but low bioavailability restricts its application in chemotherapeutic trials. A synthetic curcumin derivative hydrazinobenzoylcurcumin (HBC) had been indicated that it could inhibit cell growth in A549 lung cancer cells via cell autophagy in our previous report. The present research aims to investigate the effect of HBC on the AMP-activated protein kinase (AMPK) signaling and whether AMPK signaling is involved in HBC-induced autophagy in A549 cells. The autophagy inhibitor 3-MA was used to block the inhibitory effect of HBC on the growth of A549 cells by acridine orange assay. The phosphorylations of AMPK and its downstream factor Acetyl CoA Carboxylase (ACC) were characterized in HBCtreated A549 cells with western blot analysis. Moreover, pharmacological inhibition of the AMPK signaling pathway by Compound C impairs the autophagyinducing effect of HBC. Our data indicates that HBC could activate the AMPK signal and induce AMPKmediated autophagy, which plays an important role in the inhibiting effect of HBC in A549 cells.

영유아의 세치제 사용에 영향을 미치는 요인

최민지 ( Min-ji Choi ),박지영 ( Ji-young Park ),임미영 ( Mi-young Lim ),솨이지엔페이 ( Jianfei Shuai ),허정 ( Jung Heo ),정다영 ( Da-young Jung ),류현수 ( Hyeon-su Ryu ),오나래 ( Na-rae Oh ),김순신 ( Sun-shin Kim ),양원호 ( Won-ho Y 한국치위생학회(구 한국치위생교육학회) 2017 한국치위생학회지 Vol.17 No.1

Objectives: This study was conducted to suggest the necessity of education about toothpaste usage to infants, preschoolers, and their parents. Also, another purpose is to provide basic data that is necessary for oral health education about accurate cognition and usage of toothpaste. Methods: From October to December 2015, we conducted a survey on parents of 0~4 years old infants and preschoolers about toothpaste usage based on the data of a questionnaire with a total of 505 subjects. The survey questions were composed of general characteristics of infants, preschoolers and their parents, and toothpaste usage. Results: Usage frequency of toothpaste for infants and preschoolers increased with age (p<0.001), and infants and preschoolers in homes with monthly income under 4 million won showed high frequency of toothpaste usage (p<0.001). Toothpaste mouth rinsing of infants and preschoolers increased with age (p<0.001), while on the other hand, toothpaste swallowing decreased (p<0.001). Conclusions: In this study, it was shown that the factors that effect toothpaste usage in infants and preschoolers were age and average monthly income of the family. This suggests the necessity of oral health education to parents about usage of toothpaste in infants and preschoolers.