期刊文献+
共找到133篇文章
< 1 2 7 >
每页显示 20 50 100
Formation mechanism of fault accommodation zones under combined stress in graben basin:Implications from geomechanical modeling
1
作者 Qi-Qiang Ren Jin-Liang Gao +3 位作者 Rong-Tao Jiang Jin Wang Meng-Ping Li Jian-Wei Feng 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期54-76,共23页
A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,in... A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation areas.This study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical modeling.Using three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation zones.Combined with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben basin.Integrating the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were summarized.Influenced by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale faults.During the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly developed.The junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation zones.During the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were furtherly inherited and developed.This stage was the molded and formative period of the FAZ,the low-order faults,and the depression in the DXFZ. 展开更多
关键词 Fault accommodation zone Graben basin Fault activity Tectonic physical simulation experiment Finite element numerical simulation Dongxin fault zone
下载PDF
Smartphone use patterns and the impact on accommodation and convergence system of the eyes among Malaysian teenagers
2
作者 Thilageswary Chellapan Norlaila Mat Daud Sumithira Narayanasamy 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第11期2093-2099,共7页
AIM:To determine the smartphone use patterns and effects of smartphone use on accommodation and convergence system of the eyes among Malaysian teenagers.METHODS:A total of 62 participants aged between 13 and 17y were ... AIM:To determine the smartphone use patterns and effects of smartphone use on accommodation and convergence system of the eyes among Malaysian teenagers.METHODS:A total of 62 participants aged between 13 and 17y were involved.A self-administered questionnaires containing 12 items was used to evaluate the smartphone usage patterns.This was followed by an eye examination,involving a battery of accommodation and convergence assessments before and after the smartphone use.The data analysis comprised descriptive statistics,paired t-test,and correlation coefficients.RESULTS:The use of smartphones is at a high level and at an optimal distance daily,with more than 6h a day watching video films,games,and completing school projects.Majority of the participants not reported eye strain factors and eye prescription changes with the use of digital devices.The use of a smartphone continuously for 30min was found to significantly decrease amplitude of accommodation,accommodative facility,and positive relative accommodation(P<0.001).Meanwhile,the lag of accommodation parameters and negative relative accommodation increased with the use of smartphones significantly(P<0.001).The near point of convergence(NPC)and distance and near negative fusional vergence decreased significantly(P<0.001).The NPC parameter was found to have a weak negative association with the frequency of smartphone use(R=-0.276,P<0.05).CONCLUSION:Frequent and continuous use of smartphones have increased visual stress and resulted in weakness of accommodation and vergence functions.Therefore,frequent break is mandatory when using a smartphone and appropriate visual hygiene,the 20-20-20 rule(every 20min,view something 20 feet away for 20s)are required during smartphone use to maintain visual function. 展开更多
关键词 smartphone use patterns accommodation and convergence visual function visual stress
下载PDF
Principle for the Installation of Accommodation for Sick guards in Public Health Establishments in Brazzaville in the Republic of Congo
3
作者 Alain Symphorien Ndongo Destin Gemetone Etou Christian Tathy 《Journal of Environmental Science and Engineering(B)》 CAS 2024年第2期70-79,共10页
The results of scientific studies of human social facts in the field of health show that the management of a patient should involve the patient’s entourage,whatever the status or size of the health establishment.In h... The results of scientific studies of human social facts in the field of health show that the management of a patient should involve the patient’s entourage,whatever the status or size of the health establishment.In healthcare establishments in the Congo,the following are recognised as being responsible for medical care:specialist doctors,doctors,midwives,nurses and care assistants.The patient’s family and close friends are responsible for looking after the patient and financing care.The hospital infrastructure does not provide any space for the patient warden who accompany the patient during reception and hospitalisation.This makes Congolese hospitals inefficient for patient care.How can we integrate the function of the Sick guard and the assistance of the family,in order to reduce the mortality rate and repair the harm caused to patients requiring the presence of relatives during their stay in hospital,which is considered to be a dangerous place?This article examines the functional principles for configuring the space that patient warden would occupy in the patient care system.On the basis of a documentary analysis of sociological and architectural studies of existing facilities,this article proposes a typical accommodation model with the spaces needed to ensure the well-being and effectiveness of the patient warden with the patient.These are rooms with minimum space for 2 to 4 individual beds,equipped with toilets and showers.The accommodation has a dining area,kitchen and laundry facilities.In the future,this accommodation will become part of the hospital estate and may be occupied by orderlies and patient warden recruited by the hospital administration. 展开更多
关键词 Sick guard patient public health establishment accommodation Republic of Congo
下载PDF
SAGeLogE: A Decision Support System for Students’ Accommodation Management
4
作者 Rôlin Gabriel Rasoanaivo Pascale Zaraté 《Journal of Computer and Communications》 2024年第3期107-145,共39页
SAGeLogE is the acronym of “Système d’Aide à la Gestion de Logements étudiants” which means student accommodation management support system. It’s a multi-criteria decision support system designed to... SAGeLogE is the acronym of “Système d’Aide à la Gestion de Logements étudiants” which means student accommodation management support system. It’s a multi-criteria decision support system designed to manage accommodation allocation for university students. Within SAGeLogE we developed the “Minimum of Ranks” (MIRA) aggregation method. MIRA method involves the application of multi-criteria decision-making methods (MCDM) to initially obtain different ranking. Thus, we chose the Weighted Sum Method (WSM), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Combined Compromise Solution (CoCoSo) methods to be implemented in SAGeLogE. To prioritize the weights of criteria, the Anality Hierarchy Process (AHP) method was used. The interest of using the MIRA method was to obtain a compromised ranking coming from these three multi-criteria decision-making methods (WSM, TOPSIS, CoCoSo). So, we know that the accommodation to be allocated to students is always lower than the number of accommodation requests received by the organization. Thus, SAGeLogE proposed a technique that makes it easier to select students ranked by the multi-criteria decision-making and MIRA methods according to a method of calculation of quota of available accommodations within university residences. Finally, university accommodation managers had a wide choice of student ranking according to the methods implemented in SAGeLogE. The SAGeLogE experiment was carried out on the site of Toamasina University in Madagascar for an academic year with 2026 student accommodation applications received. The experimentation showed the ability of SAGeLogE to achieve the result. 展开更多
关键词 MIRA Method MCDM accommodation Quota SAGeLogE
下载PDF
Coordinated planning for flexible interconnection and energy storage system in low-voltage distribution networks to improve the accommodation capacity of photovoltaic 被引量:2
5
作者 Jiaguo Li Lu Zhang +1 位作者 Bo Zhang Wei Tang 《Global Energy Interconnection》 EI CSCD 2023年第6期700-713,共14页
The increasing proportion of distributed photovoltaics(DPVs)and electric vehicle charging stations in low-voltage distribution networks(LVDNs)has resulted in challenges such as distribution transformer overloads and v... The increasing proportion of distributed photovoltaics(DPVs)and electric vehicle charging stations in low-voltage distribution networks(LVDNs)has resulted in challenges such as distribution transformer overloads and voltage violations.To address these problems,we propose a coordinated planning method for flexible interconnections and energy storage systems(ESSs)to improve the accommodation capacity of DPVs.First,the power-transfer characteristics of flexible interconnection and ESSs are analyzed.The equipment costs of the voltage source converters(VSCs)and ESSs are also analyzed comprehensively,considering the differences in installation and maintenance costs for different installation locations.Second,a bilevel programming model is established to minimize the annual comprehensive cost and yearly total PV curtailment capacity.Within this framework,the upper-level model optimizes the installation locations and capacities of the VSCs and ESSs,whereas the lower-level model optimizes the operating power of the VSCs and ESSs.The proposed model is solved using a non-dominated sorting genetic algorithm with an elite strategy(NSGA-II).The effectiveness of the proposed planning method is validated through an actual LVDN scenario,which demonstrates its advantages in enhancing PV accommodation capacity.In addition,the economic benefits of various planning schemes with different flexible interconnection topologies and different PV grid-connected forms are quantitatively analyzed,demonstrating the adaptability of the proposed coordinated planning method. 展开更多
关键词 Low-voltage distribution network Photovoltaic accommodation Flexible interconnection Energy storage system Bilevel programming
下载PDF
Scheimpflug Imaging of the Anterior Eye Segment during Standardized Accommodation Stimulation in Patients with Emmetropia, Myopia and Hypermetropia
6
作者 Olga I. Rozanova 《Open Journal of Ophthalmology》 2023年第1期73-82,共10页
Understanding of the biomechanics of the accommodative apparatus in the eyes with different refraction is important for solving the problems of theoretical and practical ophthalmology. Purpose: To determine the change... Understanding of the biomechanics of the accommodative apparatus in the eyes with different refraction is important for solving the problems of theoretical and practical ophthalmology. Purpose: To determine the changes of anterior eye segment dimensions during accommodation response in normal eyes and in patients with myopia, hypermetropia. Methods and Material: 116 eyes (56 patients aged from 18 to 30 years, refraction from -2.0 to + 2.0 D) were examined. All the patients underwent a full ophthalmological examination. The ocular anterior segment was imaged using a rotational Scheimpflug camera Pentacam HR (Oculus, Wetzlar, Germany) under non- and 3.0 D of accommodative demands. The statistical data were represented as the mean value ± standard deviation (M ± SD). The Shapiro-Wilk test was used to assess the normality distribution. Wilcoxon test was used for comparison. Results: Results showed an increase in the optical density of the crystalline lens, a pupil diameter decrease and changing of the iris profile during accommodation in all patients. An increase in the total corneal aberrations and decrease in the corneal spherical aberration were revealed only in emmetropic eyes. Conclusions: The accommodative response is a multicomponent process. Scheimpflug visualization revealed the differences in the accommodative response in normal and ametropic eyes. 展开更多
关键词 Eye accommodation Scheimpflug Imaging Pupil Response
下载PDF
A Brief Analysis of the New Translation-comparison Model——from the View of Assimilation and Accommodation
7
作者 佘阿莉 《教师》 2017年第35期48-49,共2页
关键词 NEW translation-comparison model ASSIMILATION accommodation
下载PDF
The Application of Communication Accommodation Theory to Identity Construction:A Case Study of My Fair Lady
8
作者 罗敏 《海外英语》 2012年第17期182-184,共3页
My Fair Lady is a movie about how a lower class flower girl turns to an upper class lady by simply changing her language at the help of a linguist.It demonstrates the importance of communication accommodation,especial... My Fair Lady is a movie about how a lower class flower girl turns to an upper class lady by simply changing her language at the help of a linguist.It demonstrates the importance of communication accommodation,especially convergent accommodation,in using language as code and behavior to construct identity in the target community. 展开更多
关键词 SOCIOLINGUISTICS Communication accommodation Theor
下载PDF
Gastric accommodation assessed by ultrasonography 被引量:12
9
作者 Odd Helge Gilja Johan Lunding +1 位作者 Trygve Hausken Hans Gregersen 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第18期2825-2829,共5页
Gastric accommodation is important for the understanding of the pathophysiology in functional dyspepsia and is also relevant for symptom generation in other disorders. The term gastric accommodation has at least three... Gastric accommodation is important for the understanding of the pathophysiology in functional dyspepsia and is also relevant for symptom generation in other disorders. The term gastric accommodation has at least three different meanings: The accommodation process, the accommodation reflex, and the accommodation response. The gastric accommodation process is a complex phenomenon that describes how the size of the gastric compartment changes in response to a meal. The electronic barostat is considered the gold standard in assessing gastric accommodation. Imaging methods, including MRI, SPECT, and ultrasonography may also be used, particularly in patients who are stress-responsive, e.g. functional dyspepsia patients, as a non-invasive and less stress-inducing method is favourable. Ultrasonography satisfies these criteria as it does not by itself distort the physiological response in stress-responsive individuals. 展开更多
关键词 ULTRASONOGRAPHY Gastric accommodation STOMACH BAROSTAT Gastric relaxation 3D ultrasound
下载PDF
Sonographic evaluation of proximal gastric accommodation in patients with functional dyspepsia 被引量:9
10
作者 Xiu-Ping Fan Lin Wang +3 位作者 Qiang Zhu Teng Ma Chun-Xia Xia Ya-Jing Zhou 《World Journal of Gastroenterology》 SCIE CAS 2013年第29期4774-4780,共7页
AIM: To assess the value of ultrasonography (US) in evaluation of proximal gastric accommodation disorder in patients with functional dyspepsia (FD). METHODS: Between April 2011 and March 2012, 45 patients with FD and... AIM: To assess the value of ultrasonography (US) in evaluation of proximal gastric accommodation disorder in patients with functional dyspepsia (FD). METHODS: Between April 2011 and March 2012, 45 patients with FD and 27 healthy volunteers were enrolled in this study. Two-dimensional ultrasound (2DUS) and 3-dimensional ultrasound (3DUS) were performed sequentially to measure proximal gastric area (PGA), maximal proximal gastric diameter (MPGD), and proximal gastric volume (PGV). These values were measured separately in the two groups every other 5 min for a duration of 25 min after the beginning of ingestion of a test meal. Air pocket grading was done separately for images of 2DUS and blocks of 3DUS obtained at five scanning time points. RESULTS: Both PGA and PGV of patients were significantly smaller than healthy controls (P = 0.000 and 0.002, respectively). Comparing the two parameters between the groups at each time point, the differences were also statistically significant (P = 0.000-0.013), except at 10 min for the PGV (P = 0.077). However, no overall difference was found between the groups in the MPGD measurements (P = 0.114), though it was statistically significant at a 20-minute examination point (P = 0.026). A total of 360 sets or blocks of images were obtained for both 2DUS and 3DUS. For the images analyzed by 2DUS, none were excluded because of gastric gas, and 50 (13.9%) and 310 (86.1%) sets were determined as air pockets grades 1 and 2, respectively. For the images analyzed by 3DUS, 23 (6.4%) blocks were excluded from the measurement due to presence of a large fundus air pocket (grade 3); fifty (13.9%) and 287 (79.7%) blocks were also graded as 1 and 2, respectively. CONCLUSION: Measurement of both PGA and PGV by 2DUS and 3DUS could be useful for assessment of the proximal gastric accommodation. 展开更多
关键词 Functional DYSPEPSIA GASTRIC accommodation ULTRASONOGRAPHY Diagnosis 2-dimensional ULTRASOUND 3-dimensional ULTRASOUND
下载PDF
Accommodation function comparison following use of contact lens for orthokeratology and spectacle use in myopic children: a prospective controlled trial 被引量:14
11
作者 Yang Yang Li Wang +1 位作者 Peng Li Jun Li 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2018年第7期1234-1238,共5页
AIM: To study effects of orthokeratology(Ortho-k) on accommodation function in myopic children. METHODS: A prospective, non-randomized, case-control study was performed from September to October 2016. Eighty-three... AIM: To study effects of orthokeratology(Ortho-k) on accommodation function in myopic children. METHODS: A prospective, non-randomized, case-control study was performed from September to October 2016. Eighty-three children with myopia were divided into two groups. One group was treated with the rigid contact lens for overnight Ortho-k, and the other was treated with single-vision spectacle lens(SVL). Accommodation function were assessed by accommodative amplitude(AA), accommodative sensitivity(AS), accommodative lag(Lag), negative relative accommodation(NRA), and positive relative accommodation(PRA) before and 1, 3, 6 and 12 mo after treated. RESULTS: Totally 72 myopic children were finished the follow-up: 37 in Ortho-k group and 35 in SVL group. Wearing time had a significant effect on AA, AS, Lag, and NRA of myopic children in two groups(all P〈0.05). Meanwhile, there was an interaction effect between wearing time and wearing types(FAA=5.3, FAS=45.5, FLag=7.0, FNRA=3.7, all P〈0.05). However, the between-group difference of AA(F=0.1), AS(F=3.2), Lag(F=1.1), NRA(F=0.3), and PRA(F=0.1) showed no significance. AA, AS, NRA, Lag and PRA were improved significantly in Ortho-k group within 1 to 6 mo after wearing. CONCLUSION: Wearing Ortho-k can improve the accommodation function of myopic children, which might be one of the mechanisms for myopia control. 展开更多
关键词 ORTHOKERATOLOGY accommodation MYOPIA children
下载PDF
Evaluation index system of shared energy storage market towards renewable energy accommodation scenario:A China’s Qinghai province context 被引量:13
12
作者 Baomin Fang Weiqiang Qiu +3 位作者 Maochun Wang Wei Zhou Zhenzhi Lin Fushuan Wen 《Global Energy Interconnection》 EI CAS CSCD 2022年第1期77-95,共19页
With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has ... With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has the potential to play an essential role in the accommodation of renewable energy generation.However,unified evaluation standards and methods,which can help decision-makers analyze the performance of the SES market,are still not available.In this paper,an evaluation index system of the SES market is designed based on the trading rules of China’s Qinghai province and the structure-conduct-performance(SCP)analytical model.Moreover,the definition and characteristics of the indices,which can show the performance of the SES market from different perspectives,are given.Furthermore,the ideal cases are presented as the evaluation benchmark based on the development expectation of the SES market,and the analytic hierarchy process(AHP)and the technique for order preference by similarity to an ideal solution(TOPSIS)are applied to evaluate the SES market comprehensively.Finally,a case study based on actual data of the SES trading pilot project in Qinghai shows that the evaluation index system can reflect the operation status,existing problems and influencing factors of the SES market. 展开更多
关键词 Shared energy storage(SES) Renewable energy accommodation scenario Evaluation index system Ancillary service market
下载PDF
Optimization operation model of electricity market considering renewable energy accommodation and flexibility requirement 被引量:6
13
作者 Jinye Yang Chunyang Liu +2 位作者 Yuanze Mi Hengxu Zhang Vladimir Terzija 《Global Energy Interconnection》 EI CAS CSCD 2021年第3期227-238,共12页
The renewable portfolio standard has been promoted in parallel with the reform of the electricity market,and the flexibility requirement of the power system has rapidly increased.To promote renewable energy consumptio... The renewable portfolio standard has been promoted in parallel with the reform of the electricity market,and the flexibility requirement of the power system has rapidly increased.To promote renewable energy consumption and improve power system flexibility,a bi-level optimal operation model of the electricity market is proposed.A probabilistic model of the flexibility requirement is established,considering the correlation between wind power,photovoltaic power,and load.A bi-level optimization model is established for the multi-markets;the upper and lower models represent the intra-provincial market and inter-provincial market models,respectively.To efficiently solve the model,it is transformed into a mixed-integer linear programming model using the Karush–Kuhn–Tucker condition and Lagrangian duality theory.The economy and flexibility of the model are verified using a provincial power grid as an example. 展开更多
关键词 Renewable energy accommodation Renewable portfolio standards Flexibility requirement Optimization operation Mixed-integer linear programming
下载PDF
Assessment of proximal gastric accommodation in patients with functional dyspepsia 被引量:4
14
作者 Paola Iovino Antonella Santonicola Carolina Ciacci 《World Journal of Gastroenterology》 SCIE CAS 2013年第47期9137-9138,共2页
Impaired gastric accommodation is one of the most important etiologic factors in the pathophysiology of functional dyspepsia.Ultrasound is a potential alternative method to study changes in gastric volume as a reflect... Impaired gastric accommodation is one of the most important etiologic factors in the pathophysiology of functional dyspepsia.Ultrasound is a potential alternative method to study changes in gastric volume as a reflection of gastric accommodation.Ultrasound is suitable for patients because it is a non-invasive,easily repeated and non-radioactive procedure,and a previous study has demonstrated the feasibility of 3-dimensional ultrasound in examining functional dyspepsia.The brief article by Fan et al demonstrated that both the proximal gastric area and volume,measured by 2-and 3-dimensional ultrasound respectively,were significantly smaller in patients with functional dyspepsia than in healthy controls.These results are very interesting,but we raise the relevant point that it should have been mandatory to study both changes in gastric volume and their relationship with upper gastrointestinal symptoms in functional dyspepsia.In fact,the relationship between cardinal symptoms and several pathophysiologic mechanisms in functional dyspepsia remains a matter of debate.Moreover,further evaluation of distal gastric volume that has been previously implicated in the origin of functional dyspeptic symptoms is advisable.Therefore,impaired gastric accommodation does not serve as a clear marker of the cardinal symptoms experienced by patients with functional dyspepsia in daily life. 展开更多
关键词 Proximal gastric function Gastric accommodation 2-Dimensional ultrasound 3-Dimensional ultrasound Functional dyspepsia Rome III criteria
下载PDF
Unveiling the mechanical response and accommodation mechanism of pre-rolled AZ31 magnesium alloy under high-speed impact loading 被引量:4
15
作者 Xiao Liu Hui Yang +3 位作者 Biwu Zhu Yuanzhi Wu Wenhui Liu Changping Tang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2022年第4期1096-1108,共13页
Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s^(-1) and 4160s-1.The mechanical response,microstructural evolution and accommo... Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s^(-1) and 4160s-1.The mechanical response,microstructural evolution and accommodation mechanism of the pre-rolled AZ31 magnesium alloy under high-speed impact loading were investigated.The twin and shear band are prevailing at low temperature,and the coexistence of twins and recrystallized grains is the dominant microstructure at medium temperature,while at high temperature,dynamic recrystallization(DRX)is almost complete.The increment of temperature reduces the critical condition difference between twinning and DRX,and the recrystallized temperature decreases with increasing strain rate.The mechanical response is related to the competition among the shear band strengthen,the twin strengthen and the fine grain strengthen and determined by the prevailing grain structure.The fine grain strengthen could compensate soften caused by the temperature increase and the reduction of twin and shear band.During high-speed deformation,different twin variants,introduced by pre-rolling,induce different deformation mechanism to accommodate plastic deformation and are in favor for non-basal slip.At low temperature,the high-speed deformation is achieved by twinning,dislocation slip and the following deformation shear band at different deformation stages.At high temperature,the high-speed deformation is realized by twinning and dislocation slip of early deformation stage,transition shear band of medium deformation stage and DRX of final deformation stage. 展开更多
关键词 Mechanical response Pre-twinning accommodation mechanism Pre-rolled AZ31 magnesium alloy High-speed impact loading
下载PDF
Fault Accommodation for a Class of Nonlinear Uncertain Systems With Event-Triggered Input 被引量:3
16
作者 Dong Zhao Marios M.Polycarpou 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第2期235-245,共11页
The event-triggered fault accommodation problem for a class of nonlinear uncertain systems is considered in this paper.The control signal transmission from the controller to the system is determined by an event-trigge... The event-triggered fault accommodation problem for a class of nonlinear uncertain systems is considered in this paper.The control signal transmission from the controller to the system is determined by an event-triggering scheme with relative and constant triggering thresholds.Considering the event-induced control input error and system fault threat,a novel eventtriggered active fault accommodation scheme is designed,which consists of an event-triggered nominal controller for the time period before detecting the occurrence of faults and an adaptive approximation based event-triggered fault accommodation scheme for handling the unknown faults after detecting the occurrence of faults.The closed-loop stability and inter-event time of the proposed fault accommodation scheme are rigorously analyzed.Special cases for the fault accommodation design under constant triggering threshold are also derived.An example is employed to illustrate the effectiveness of the proposed fault accommodation scheme. 展开更多
关键词 Adaptive control event-triggered control fault accommodation neural networks nonlinear systems
下载PDF
Fault detection and accommodation via neural network and variable structure control 被引量:3
17
作者 Hao YANG Bin JIANG 《控制理论与应用(英文版)》 EI 2007年第3期253-260,共8页
This paper proposes a novel idea that classifies faults into two different kinds: serious faults and small faults, and treats them with different strategies respectively. A kind of artificial neural network (ANN) i... This paper proposes a novel idea that classifies faults into two different kinds: serious faults and small faults, and treats them with different strategies respectively. A kind of artificial neural network (ANN) is proposed for detecting serious faults, and variable structure (VS) model-following control is constructed for accommodating small faults. The proposed framework takes both advantages of qualitative way and quantitative way of fault detection and accommodation. Moreover, the uncertainty case is investigated and the VS controller is modified. Simulation results of a remotely piloted aircraft with control actuator failures illustrate the performance of the developed algorithm. 展开更多
关键词 Fault detection Fault accommodation Neural network Variable structure control
下载PDF
Effect of Laser in situ Keratomileusis on Accommodation 被引量:2
18
作者 刘磊 袁菁 +2 位作者 栗静 李新宇 王渝龙 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2008年第5期596-598,共3页
The accommodative function before and after laser in situ keratomileusis (LASIK) was observed, and the effect of LASIK on accommodation was investigated. In a prospective clinical trial, 48 myopic patients (96 eyes... The accommodative function before and after laser in situ keratomileusis (LASIK) was observed, and the effect of LASIK on accommodation was investigated. In a prospective clinical trial, 48 myopic patients (96 eyes) subject to bilateral LASIK in Refractive Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (China) from March 2006 to June 2006 were selected and studied. Refractions, accommodative range, amplitude of accommodative response and high frequency component (HFC) of accommodative microfluctuations were measured with NEDIK-730A before and one week and 30 days after operation. Dominant and non-dominant eyes were determined by hole-in-card method. It was found that all of the operative eyes showed an uncorrected visual acuity of 0.8 or better one week postoperatively, and 1.0 or better 30 days postoperatively. Compared with those preoperatively, accommodative range and HFC had no significant difference at first week and 30th day after operation in both dominant eyes and non-dominant eyes (P〉0.05), but there was a significant difference in the amplitude of accommodative response/accommodative stimulus ratio (A/S) after operation (P〈0.01), and no significant difference was found in accommodation between one week and 30 days postoperation. No ocular dominance's change was noted. There was no significant difference in accommodative function between dominant eyes and non-dominant eyes. It was suggested that LASIK produced no significant effect on accommodation. 展开更多
关键词 laser in situ keratomileusis accommodation dominant eye
下载PDF
Accommodation in human eye models:a comparison between the optical designs of Navarro,Arizona and Liou-Brennan 被引量:1
19
作者 Georgios Zoulinakis Jose Juan Esteve-Taboada +2 位作者 Teresa Ferrer-Blasco David Madrid-Costa Robert Montés-Mico 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2017年第1期43-50,共8页
AIM: To simulate and compare accommodation in accommodative and non-accommodative human eye models.METHODS: Ray tracing and optical design program was used. Three eye models were designed and studied: the Navarro, ... AIM: To simulate and compare accommodation in accommodative and non-accommodative human eye models.METHODS: Ray tracing and optical design program was used. Three eye models were designed and studied: the Navarro, the Arizona and the Liou-Brennan. In order to make the Navarro and Liou-Brennan models to accommodate, specific geometric parameters of the models were altered with values that were chosen from the literature. For the Arizona model, its’ mathematical functions for accommodation were used for the same accommodative demands. The simulation included four distances of accommodation for each model: at infinity, 3, 1 and 0.5 m.The results were diffraction images of a “letter F” for graphical comparison, spot diagrams on the retinal field and Modulation Transfer Function (MTF) graphs.RESULTS:Zernike coefficients for the aberrations, Airy disk diameter, root mean square (RMS) error diameter and total axial length of the model were provided from the program. These were compared between them in all distances. The Navarro model had the smallest axial length change as a simple model. The Arizona did not change its axial length because it is designed to be accommodative. The Liou-Brennan model had different results concerning the aberrations because of the decentration of the pupil. The MTF graphs showed small differences between the models because of the differences in their designs.CONCLUSION: All the three models are able to simulate accommodation with the expected results. There is no model that can be assumed as the best choice. Accommodation can be simulated in non-accommodativemodels and in customized ones. 展开更多
关键词 accommodation design eye MODEL OPTICAL
下载PDF
Lag of accommodation predicts clinically significant change of spherical equivalents after cycloplegia 被引量:1
20
作者 Cheng-Cheng Jin Ru-Xia Pei +4 位作者 Bei Du Gui-Hua Liu Nan Jin Lin Liu Rui-Hua Wei 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2021年第7期1052-1058,共7页
AIM: To evaluate related factors with the change of spherical equivalents(ΔSE) and determine the suitable predictor of clinically significant ΔSE(≥0.50 D) with cyclopentolate hydrochloride on Chinese children. METH... AIM: To evaluate related factors with the change of spherical equivalents(ΔSE) and determine the suitable predictor of clinically significant ΔSE(≥0.50 D) with cyclopentolate hydrochloride on Chinese children. METHODS: A total of 145 right eyes of 145 children aged 4 to 15 y were enrolled. Intraocular pressure, axial length and lag of accommodation(LOA) were assessed before cycloplegia induced by 3 drops of 1% cyclopentolate at 5-minute intervals. SE was measured before and 1 h after the first drop of cyclopentolate. ΔSE was compared between different gender groups and among refractive groups. Multivariate linear regression analysis was performed to find related factors with ΔSE. ROC analysis was used to figure out the suitable predictor of clinically significant ΔSE.RESULTS: For the total 145 eyes, the mean SE reached up to-0.70±1.86 D from-1.30±1.62 D, with the mean ΔSE of 0.60±0.55 D. The mean ΔSE were 0.63±0.55 D and 0.57±0.56 D respectively in the male and female group(P=0.40). The mean ΔSE was significantly different among different refractive groups(P<0.0001), with the ΔSE of hyperopia group(1.12±0.64 D) larger than that of the emmetropia(0.56±0.43 D, P=0.001) and myopia group(0.32±0.28 D, P<0.0001). The ΔSE was correlated with LOA(B=-0.54, P<0.0001), cycloplegic SE(B=0.10, P<0.0001) and age(B=-0.04, P=0.015). ROC curve indicated that LOA predicted clinically significant ΔSE by 82% [area under the curve(AUC)=0.82] alone, while the value was slightly improved to 85%(AUC=0.85) in combination with axial length and 86%(AUC=0.86) in association with axial length as well as age.CONCLUSION: After cycloplegia with cyclopentolate, the ΔSE decreases with larger LOA, longer axial length and older age. Specifically, LOA plays a more vital role in predicting clinically significant ΔSE. 展开更多
关键词 CYCLOPLEGIA CYCLOPENTOLATE spherical equivalent clinically significant change lag of accommodation
下载PDF
上一页 1 2 7 下一页 到第
使用帮助 返回顶部