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Luís F. P. Silva,Valter J. S. Leite,Eugênio B. Castelan,Gang Feng 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.3
We propose convex conditions for stabilization of nonlinear discrete-time systems with time-varying delay in states through a fuzzy Takagi-Sugeno (T-S) modeling. These conditions are developed from a fuzzy Lyapunov-Krasovskii function and they are formulated in terms of linear matrix inequalities (LMIs). The results can be applied to a class of nonlinear systems that can be exactly represented by T-S fuzzy models inside a specific region called the region of validity. As a consequence, we need to provide an estimate of the set of safe initial conditions called the region of attraction such that the closed-loop trajectories starting in this set are assured to remain in the region of validity and to converge asymptotically to the origin. The estimate of the region of attraction is done with the aid of two sets: one dealing with the current state, and the other concerning the delayed states. Then, we can obtain the feedback fuzzy control law depending on the current state, xk, and the maximum delayed state vector, xk-d. It is shown that such a control law can locally stabilize the nonlinear discrete-time system at the origin. We also develop convex optimization procedures for the computation of the fuzzy control gains that maximize the estimates of the region of attraction. We present two examples to demonstrate the efficiency of the developed approach and to compare it with other approaches in the literature.
HYERS-ULAM STABILITY OF DERIVATIONS IN FUZZY BANACH SPACE: REVISITED
Gang Lu,Yuanfeng Jin,Gang Wu,Sungsik Yun 한국수학교육학회 2018 純粹 및 應用數學 Vol.25 No.2
Lu et al. [27] dened derivations on fuzzy Banach spaces and fuzzy Lie Banach spaces and proved the Hyers-Ulam stability of derivations on fuzzy Banach spaces and fuzzy Lie Banach spaces. It is easy to show that the denitions of derivations on fuzzy Banach spaces and fuzzy Lie Banach spaces are wrong and so the results of [27] are wrong. Moreover, there are a lot of seroius problems in the statements and the proofs of the results in Sections 2 and 3. In this paper, we correct the denitions of biderivations on fuzzy Banach algebras and fuzzy Lie Banach algebras and the statements of the results in [27], and prove the corrected theorems.
Direct Observation of Radiative Flux in the Southern Yellow Sea
Lu, Lian-Gang,Yu, Fei,Diao, Xinyuan,Guo, Jingsong,Wang, Huiwu,Wei, Chuanjie The Korean Society of Oceanography 2008 Ocean science journal Vol.43 No.2
Direct measurements of four radiative components at air-sea boundary layer were conducted in the southern Yellow Sea during three cruises (seasons) in 2007. Simultaneous observations of meteorological (cloud cover, air temperature and humidity) and oceanographic (sea surface temperature) parameters were carried out. Observational results of radiative fluxes and meteorological and oceanographic parameters are presented. Mean diurnal cycles of four radiative components, net radiation, and sea surface albedo are calculated to achieve averages in different seasons. Net radiative fluxes in three seasons (winter, spring, autumn) are 8, 146, $60\;W/m^2$, respectively. Comparisons between the observed radiative fluxes and those estimated with formulas are taken.
Effect of nano-composite materials on repair of ligament injury in sports detoxification
Lu, Chunxia,Lu, Gang,Dong, Weixin,Liu, Xia Techno-Press 2022 Advances in nano research Vol.13 No.3
Extraordinary properties of nanocomposites make them a primary replacement for many conventional materials. Anterior cruciate ligament (ACL) reconstruction, which is a frequent surgery in sport activities, is one of the fields in which nanocomposites could be utilized. In the present study, the mechanical properties of different porous scaffolds made from graphene nano-composites are presented ad load bearing capacity of these materials is calculated using finite element method. The numerical results are further compared with experimental published data. In addition, several geometrical and material parameters are analyzed to find the best configuration of nanocomposite scaffolds in reconstruction of ACL. Moreover, coating of detoxification chemicals are extremely easier on the nano-structured materials than conventional one. Detoxification potential of nano-composites in the injured body are also discussed in detail. The results indicated that nano-composite could be successfully used in place of auto- and allografts and also instead of conventional metallic screws in reconstruction of ACL.
Gang Lu,Changgeng Shuai,Yinsong Liu,Xue Yang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1
Synergistic effects have been extensively investigated in the modification of polymer materials. To gain complete insights into the effect of two-component synergy on the tribology performance of thermoplastic polyurethane (TPU), this study selected single-wall carbon nanotubes (SWNTs) and MoS 2 as the solid additives to prepare several composite materials. Subsequently, the tribology property of the composites was analyzed. It was reported that the agglomeration phenomenon could be improved by regulating the ratio of SWNTs and MoS 2 . In addition, SWNTs could effectively improve the friction and wear properties exhibited by the composites and promote the mechanical properties exhibited by the composites. Moreover, the positive effect on tribological properties was increasingly significantly as the contact load increased.
A numerical study on the damage of projectile impact on concrete targets
Gang Lu,Xibing Li,Kejin Wang 사단법인 한국계산역학회 2012 Computers and Concrete, An International Journal Vol.9 No.1
This paper presents the numerical simulation of the rigid 12.6 mm diameter kinetic energy ogive-nosed projectile impact on plain and fiber reinforced concrete (FRC) targets with compressive strengths from 45 to 235 MPa, using a three-dimensional finite element code LS-DYNA. A combined dynamic constitutive model, describing the compressive and tensile damage of concrete, is implemented. A modified Johnson_Holmquist_Cook (MJHC) constitutive relationship and damage model are incorporated to simulate the concrete behavior under compression. A tensile damage model is added to the MJHC model to analyze the dynamic fracture behavior of concrete in tension, due to blast loading. As a consequence, the impact damage in targets made of plain and fiber reinforced concrete with same matrix material under same impact velocities (650 m/s) are obtained. Moreover, the damage distribution of concrete after penetration is procured to compare with the experimental results. Numerical simulations provide a reasonable prediction on concrete damage in both compression and tension.
Vertical Migration of Sound Scatterers in the Southern Yellow Sea in Summer
Lu, Lian-Gang,Liu, Jianjun,Yu, Fei,Wu, Wei,Yang, Xiaodong The Korean Society of Oceanography 2007 Ocean science journal Vol.42 No.1
Acoustic volume backscattering strength data were collected and Conductivity Temperature Depth (CTD) measurements were conducted in the southern Yellow Sea in summer 2005 and 2006. The high temporal and vertical resolution acoustic data measured with a 307 kHz Acoustic Doppler Current Profiler (ADCP) and a 250 kHz acoustic Doppler profile (ADP) had dominant diel variation, which resulted from vertical migration of sound scatterers. Some scatterers congregating in the bottom layer in the daytime migrated upward at dusk, and migrated downward into the bottom layer at dawn. The migration speeds were estimated. More than 33 days data show that the diel migration varies with time. The feature of migration measured with ADCP and ADP is consistent to some extent with what is described in the study on vertical migration of zooplankton in the southern Yellow Sea with conventional net samples.
Xin-gang Lu,Yan-ping Ma,Xing-hua Liu 한국원예학회 2012 Horticulture, Environment, and Biotechnology Vol.53 No.5
Fuji’ apple fruit harvested 10 days before normal harvest (H1) and at normal harvest (H2) were untreated or treated with 1 ㎕·L-1 1-methylcyclopropene (1-MCP) and stored at 0 for up to 30 weeks. Fruits from H1 were firmer and had higher titratable acidity (TA) but lower soluble solids concentrations than those from H2. 1-MCP treatment delayed loss of firmness and TA in fruit from both harvests during storage. Superficial scald incidence was decreased by 1-MCP treatment, but flesh browning was unaffected. H2 fruit had higher total phenolics, flavonoid, and glutathione content as well as total antioxidant activity than H1 fruit at harvest and throughout storage. 1-MCP treated fruit tended to have higher levels of these constituents than untreated fruit in peel, but not in flesh tissues. These results suggest that fruit harvested at the mature stage have better integral quality with 1-MCP treatment.