Cumulative probability and risk analysis for Nd:YAG laser capsulotomy

AIM: To estimate the cumulative probability of Nd:YAG capsulotomy at a teaching institution and evaluate secondary risk factors.METHODS: The records of all patients who underwent phacoemulsification with intraocular lens(IOL) placement between 2005-2010 were retrospectively reviewed. The cumulative probability of Nd:YAG capsulotomy(capsulotomy) was calculated using KaplanMeier survival analysis and secondary risk factors were evaluated using the Cox proportional hazards regression model. RESULTS: One thousand three hundred and fifty four charts were reviewed. A total of 70 capsulotomies wereperformed. The mean follow-up was 19.4 mo(standard deviation 17 mo). The cumulative probability of capsulotomy was 4% at 1 year, 5% at 2 year, and 9% at 3 year. Multivariate analysis demonstrated an increased risk with younger age(HR = 1.03, CI 1.01-1.05, P = 0.007), placement of sulcus IOL(HR = 2.57, CI 1.32-4.99, P = 0.005), ocular trauma(HR = 2.34, CI 1.13-4.83, P = 0.02), and phacoemulsification by a more experienced surgeon(HR = 4.32, CI 1.89-9.87, P = 0.001).CONCLUSION: Cumulative probability of capsulotomy was lower than previously reported. Posterior capsule opacification was strongly associated with younger age and factors associated with high-risk cataract surgery. Surgeon awareness to the risk factors that correlate with posterior capsulotomy may allow for more thorough pre-operative disclosure and enhance patient satisfaction.

Extracting classification rules based on a cumulative probability distribution approach

This paper deals with a reinforced cumulative probability distribution approach (CPDA) based method for extracting classification rules.The method includes two phases:(1) automatic generation of the membership function,and (2) use of the corresponding linguistic data to extract classification rules.The proposed method can determine suitable interval boundaries for any given dataset based on its own characteristics,and generate the fuzzy membership functions automatically.Experimental results show that the proposed method surpasses traditional methods in accuracy.

Seismic loss assessment of RC high-rise buildings designed according to Eurocode 8

A probabilistic seismic loss assessment of RC high-rise(RCHR)buildings designed according to Eurocode 8 and located in the Southern Euro-Mediterranean zone is presented herein.The loss assessment methodology is based on a comprehensive simulation approach which takes into account ground motion(GM)uncertainty,and the random effects in seismic demand,as well as in predicting the damage states(DSs).The methodology is implemented on three RCHR buildings of 20-story,30-story and 40-story with a core wall structural system.The loss functions described by a cumulative lognormal probability distribution are obtained for two intensity levels for a large set of simulations(NLTHAs)based on 60 GM records with a wide range of magnitude(M),distance to source(R)and different site soil conditions(SS).The losses expressed in percent of building replacement cost for RCHR buildings are obtained.In the estimation of losses,both structural(S)and nonstructural(NS)damage for four DSs are considered.The effect of different GM characteristics(M,R and SS)on the obtained losses are investigated.Finally,the estimated performance of the RCHR buildings are checked to ensure that they fulfill limit state requirements according to Eurocode 8.

Array gain of fourth-order cumulants beamforming under typical probability density background

The fourth-order cumulant of zero mean Gaussian distribution noise always equals to zero theoretically. In practice the probability density of noise and reverberation is the key problem to performance of the fourth-order cumulant beamforming technique. In this paper, the array gain functions of the fourth-order cumulant beamforming are deducted considering the instantaneous amplitude distribution of the ambient sea noise and bottom reverberation respectively. And the relationships are determined between array gain and the factors including the number of the array elements, the fourth-order and second-order statistical properties of the noise and reverberation, and the input signal-to-noise ratio. It is also verified that there is a critical signal-to-interference ratio and the fourth-order cumulant beamforming can obtain higher gain and resolution than the conventional beamforming method when the ratio is larger than it. The results of experiment data processing demonstrate that the gain and the resolution of the fourth-order cumulant beamforming coincide with the theoretic.

Order Execution Probability and Order Queue in Limit Order Markets

The shaping of a limit order book illustrates the dynamics of the trading process,the changing pattern of the execution probability of limit orders therefore plays an important role.This paper presents a computable execution probability model for limit order market,as well as a numerical example that intuitively characterizes the changing pattern of the execution probability.The common effects of the lengths of both buy and sell queues on the execution probability are explored.In the limit book,the cumulative probability of limit orders is introduced as a crucial index of market depth to describe the shaping process which brings new insights into the structure of the order placement decision.

An Emergency Shelter Location Model Based on the Sense of Security and the Reliability Level

Based on the value function of the prospect theory,this paper constructs a security function,which is used to describe the victims’feelings about the distance in emergency evacuation.Since different paths between the demand points and the emergency shelters are generally of different importance degrees,they are divided into main paths and auxiliary paths.The security function values and the reliability levels of main paths and auxiliary paths are given different weights.The weighted sum of the security function values and the weighted sum of the reliability level function values of all demand points are maximized to determine the location and the number of the emergency shelters,the transfer paths,the reinforced edges and the incremental reliability level of the selected edge.In order to solve the model,a two-stage simulated annealing-particle swarm optimization algorithm is proposed.In this algorithm,the particle swarm optimization(PSO)algorithm is embedded into the simulated annealing(SA)algorithm.The cumulative probability operator and the cost probability operator are formed to determine the evolution of the particles.Considering the budget constraint,the algorithm eliminates the shelter combinations that do not meet the constraint,which greatly saves the calculation time and improves the efficiency.The proposed algorithm is applied to a case,which verifies its feasibility and stability.The model and the algorithm of this paper provide a basis for emergency management departments to make the earthquake emergency planning.

Research on pedestrian escape route without visibility based on Markov chain model

It is a pioneering work to use a Markov chain model to study the pedestrian escape route without visibility.In this paper,based on the Markov chain probability transition matrix,the algorithms with random numbers and the spatial-grid,an escape route in a limited invisible space is obtained.Six pace states(standing,crawling,walking,leaping,jogging,and running)are applied to describe the characteristics of pedestrian behaviors.Besides,eight main direction changes are used to describe the transition characteristic of a pedestrian.At the same time,this paper analyzes the escape route from two views,i.e.,pedestrian pace states and directions.The research results show that the Markov chain model is more realistic as a means of studying pedestrian escape routes.

Regional moment-independent sensitivity analysis with its applications in engineering

Traditional Global Sensitivity Analysis（GSA） focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function（RIMPDF） and Regional Importance Measure based on Cumulative Distribution Function（RIMCDF）,are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.

Estimation of Fracture Toughness for A508-III Steel in Ductile-to-Brittle Transition Region Using a Strain-Energy–Density-Based Fracture Failure Model

According to the assumption of intrinsic relationship between ultimate strain energy density and microcrack nucleation,this work developed a fracture failure model to estimate the fracture toughness of A508-III steel in the ductile-to-brittle transition region.The fracture toughness and uniaxial tension tests at different temperatures were carried out to determine the relationship between nucleation parameter and ultimate strain energy density,from which the evolutions of fracture toughness of A508-III ferritic steel for different cumulative failure probabilities at different temperatures were predicted.The fracture failure model can well describe the fracture toughness distribution of A508-III steel in the ductile-to-brittle transition region.Compared with the master curve method,this model has better temperature adaptability.It is more convenient to calibrate the parameters of this model compared with the traditional Beremin model,and without complex finite element analysis.