Comparison of visual acuity of the patients on the first day after sub-Bowman keratomileusis or laser in situ keratomileusis

AIM：To compare recovery of the visual acuity in patients one day after sub-Bowman keratomileusis（SBK）or laser in situ keratomileusis（LASIK）.· METHODS：Data from 5923 eyes in 2968 patients that received LASIK（2755 eyes） or SBK（3168 eyes） were retrospectively analyzed.The eyes were divided into 4groups according to preoperative spherical equivalent：between-12.00 to-9.00 D,extremely high myopia（n =396,including 192 and 204 in SBK and LASIK groups,respectively）;-9.00 to-6.00 D,high myopia（n=1822,including 991 and 831 in SBK and LASIK groups,respectively）,-6.00 to-3.00 D,moderate myopia（n=3071,including 1658 and 1413 in SBK and LASIK groups,respectively）,and-3.00 to 0.00 D,low myopia（n =634,including 327 and 307 in SBK and LASIK groups,respectively）.Uncorrected logMAR visual acuity values of patients were assessed under standard natural light.Analysis of variance was used for comparisons among different groups.· RESULTS：Uncorrected visual acuity values were0.0115±0.1051 and 0.0466±0.1477 at day 1 after operation for patients receiving SBK and LASIK,respectively（P〈0.01）;visual acuity values of 0.1854±0.1842,0.0615±0.1326,-0.0033±0.0978,and-0.0164±0.0972 were obtained for patients in the extremely high,high,moderate,and low myopia groups,respectively（P〈0.01）.In addition,significant differences in visual acuity at day 1 after operation were found between patients receiving SBK and LASIK in each myopia subgroup.· CONCLUSION：Compared with LASIK,SBK is safer and more effective,with faster recovery.Therefore,SBK is more likely to be accepted by patients than LASIK for better uncorrected visual acuity the day following operation.

Degradation data-driven approach for remaining useful life estimation

Remaining useful life （RUL） estimation is termed as one of the key issues in prognostics and health management （PHM）. To achieve RUL estimation for individual equipment, we present a degradation data-driven RUL estimation approach under the collaboration between Bayesian updating and expectation maximization （EM） algorithm. Firstly, we utilize an exponential-like degradation model to describe equipment degradation process and update stochastic parameters in the model via Bayesian approach. Based on the Bayesian updating results, both probability distribution of the RUL and its point estimation can be derived. Secondly, based on the monitored degradation data to date, we give a parameter estimation approach for non-stochastic parameters in the degradation model and prove that the obtained estimation is unique and optimal in each iteration. Finally, a numerical example and a practical case study for global positioning system （GPS） receiver are provided to show that the presented approach can model degradation process and achieve RUL estimation effectively and generate better results than a previously reported approach in literature.

An Overview of Research in Distributed Attitude Coordination Control

This paper provides an overview of attitude coordination problems of multi-rigid-body with the goal of promoting research in this area. Theoretical results regarding consensus seeking with different system models, different communication topologies, different control goals and different techniques are summarized. And applications of consensus protocols to multirigid- body coordination are investigated. Finally, some future research directions and open problems are also proposed. © 2014 Chinese Association of Automation.

Decision-oriented Usability Evaluation of an Operation Interface: Model and Application

To support multi-factor decision problems about usability evaluation, especially when studies fall short of comparable objects, a fuzzy synthetic evaluation model is explored in this paper. Grey relational analysis （GRA） is brought in the model to calculate weight vectors of the usability factors. And membership functions of a remark vector are constructed in the context of use of the operation interface. The present method is applied in usability evaluation of operation interface and is proved to be effective. The comprehensive usability gradation of the operation interface to good is 0. 616 4 that meets the requirements in practice.

Real-Time Rendering of Dynamic Clouds Using Multi-Resolution Adaptive Grids

The multi-resolution adaptive grids method is proposed to solve the problems of inefficiency in the previous grid-based methods,and it can be used in clouds simulation as well as the interactive simulation between objects and clouds.Oriented bounding box(OBB)hierarchical trees of objects are established,and the resolutions of global and local grids can be selected automatically.The motion equations of fluid dynamics are simplified.Upwind difference is applied to ensure the stability of the simulation process during the discrete process of partial differential equations.To solve the speed problem of existed phase functions,the improved phase function is applied to the illumination calculation of clouds.Experimental results show that the proposed methods can promote the simulation efficiency and meet the need for the simulation of large-scale clouds scene.Real-time rendering of clouds and the interaction between clouds and objects have been realized without preprocessing stage.

Discussion on Atmospheric Pollutant Source Seeking Model with Surface Soil Sample

Through the analysis on the migratory diffusion process of atmospheric pollutants,we proposed to seek atmospheric pollutant source with surface soil sample of data.Based on Gaussian plume model and deposition model,atmospheric pollutants distribution model was deduced,with which a schema matching source seeking model was established.The model was used to seek the pollutant source by using the arsenic data in the surface soil sample of a city.

Analysis of Technical Properties of Wind and Solar Photovoltaic Power

Most of electricity power in China comes from coal and hydropower. Already, China must import nearly half of its oil. Concerns about power capacity shortages and air pollution are all adding urgency and pressure to switch to alternative technologies and renewable energy. Among renewable energy sources, wind power and solar photovoltaic power are playing key roles in China, and are the fastest-growing power generation technologies. So this paper focuses on them and analyzes the corresponding technical properties of them. First of all, wind power transforms the kinetic energy from the wind into electricity by using wind turbines. Thus the basic components of wind turbines are described. Wind speed is an important factor to wind energy. So the features of wind speed are analyzed, and the wind energy is calculated. Second, the technical properties of solar photovoltaic power are discussed, including photovoltaic cells and modules, battery, inverter and photovoltaic controller. Photovoltaic energy is also analyzed and calculated. Third, the environmental impacts of wind power and solar photovoltaic power are presented. Finally, the relevant conclusions are drawn.

A novel SMC-PHD filter based on particle compensation

As a typical implementation of the probability hypothesis density(PHD) filter, sequential Monte Carlo PHD(SMC-PHD) is widely employed in highly nonlinear systems. However, the particle impoverishment problem introduced by the resampling step, together with the high computational burden problem, may lead to performance degradation and restrain the use of SMC-PHD filter in practical applications. In this work, a novel SMC-PHD filter based on particle compensation is proposed to solve above problems. Firstly, according to a comprehensive analysis on the particle impoverishment problem, a new particle generating mechanism is developed to compensate the particles. Then, all the particles are integrated into the SMC-PHD filter framework. Simulation results demonstrate that, in comparison with the SMC-PHD filter, proposed PC-SMC-PHD filter is capable of overcoming the particle impoverishment problem, as well as improving the processing rate for a certain tracking accuracy in different scenarios.

Current Practice in Measuring the Quality of Conceptual Models:Challenges and Research

How to measure the quality of conceptual models is an important issue in the IS field and related research. This paper conducts a review of research in measuring conceptual model quality and identifies the major theoretical and practical issues that need to be addressed in future studies. We review current classification frameworks for conceptual model quality and practice of measuring conceptual model quality. Based on the review, challenges for studies of measuring the quality of conceptual models are proposed and these challenges are also research points which should be strengthened in future studies.