Retinal vessel segmentation using a probabilistic tracking method

Vessel structures such as retinal vasculature are important features for computer-aided diagnosis. In this paper, a probabilistic tracking method is proposed to detect blood vessels in retinal images. During the tracking process, vessel edge points are detected iteratively using local grey level statistics and vessel's continuity properties. At a given step, a statistic sampling scheme is adopted to select a number of vessel edge points candidates in a local studying area. Local vessel's sectional intensity profiles are estimated by a Gaussian shaped curve. A Bayesian method with the Maximum a posteriori (MAP) probability criterion is then used to identify local vessel's structure and find out the edge points from these candidates. Evaluation is performed on both simulated vascular and real retinal images. Different geometric shapes and noise levels are used for computer simulated images, whereas real retinal images from the REVIEW database are tested. Evaluation performance is done using the Segmentation Matching Factor (SMF) as a quality parameter. Our approach performed better when comparing it with Sun's and Chaudhuri's methods. ROC curves are also plotted, showing effective detection of retinal blood vessels (true positive rate) with less false detection (false positive rate) than Sun's method.     

Investigations into the copper chromite particle size effect on the combustion characteristics of poly(vinyl-chloride) plastisol propellants

Journal of Mechanical Science and Technology - The investigation of the possibility to optimize ballistic behavior and consequently to obtain better performance without affecting the cost and...     

Injury incidence rates of cyclists compared to pedestrians,car occupants and powered two-wheeler riders,using a medical registry and mobility data,Rhône County,France

Purpose

In France, the bicycle's modal share is stabilizing after a decline; in some of France's major cities, it has even increased since the 1990s. It is hence relevant to improve the knowledge of the injury risk associated with cycling, compared with other means of transport such as car, walking and powered two-wheeler (PTW) riding.

Methods

The injury incidence rates were estimated by the ratio between accident data and mobility (exposure) data. Two accident data sources were used: police data and hospital-based data (outpatients and inpatients) from the Rhône road trauma Registry. This provides four injury categories: all-injury, hospitalization, serious-injury and fatal-injury. Exposure data were estimated from a regional household travel survey (RTS), using three measures of mobility: number of trips, distance traveled and time spent traveling. The survey was carried out from November 2005 to April 2006, on weekdays, outside school and public holidays; this seasonality was corrected using the 2007–2008 national household travel survey (NTS) that covered an entire year. Only information involving accidents and trips in, and residents of, the Rhône County (1.6 million inhabitants, including the city Lyon) were included in our study. Trends of injury rates were also evaluated in Greater Lyon, using previous travel surveys.

Results

The PTW riders had the highest all-injury, hospitalization, serious-injury and fatal-injury rates, followed by cyclists, and lastly by pedestrians and car occupants. The rates between men and women seemed similar among pedestrians and among car occupants. For car occupants, pedestrians and cyclists, the age group 18–25 years had higher all-injury rate compared with the age group 25–65 years. On the contrary, the age group ≥65 years seemed to have higher hospitalization and serious-injury rates, compared with the age group 25–65 years. For cyclists, the injury rates seemed higher in non-dense areas than in dense areas. Between 1996–1997 and 2005–2006 and with regards to time spent traveling, the all-injury, serious-injury and fatal-injury rates seemed to have decreased for car occupants and cyclists.

Conclusion

The higher risk for PTW riders is confirmed and quantified; it is very high. Decrease in injury rates seems more marked for cyclists; this may indicate the “safety in numbers” effect. Countermeasures for improving road safety could be implemented, especially for vulnerable road user types. However, they will not be sufficient to fill in the gap between the much higher risk for PTW riders and that of car occupants. Exposure-based injury rates can be a tool for monitoring and evaluating the effectiveness of policies and programs, and for comparisons between countries.     

Nonlinear Propagation of Ion-Acoustic Shock waves in Dissipative Electron–Positron–Ion Plasmas with Superthermal Electrons and Relativistic Ions

A weakly nonlinear analysis is carried out to derive the appropriate Korteweg–de Vries–Burgers-like equation for small, but finite amplitude, ion-acoustic waves in a dissipative plasma consisting of relativistic ions, Maxwell–Boltzmann distributed positrons and superthermal electrons. Our results show that in a such plasma, ion-acoustic shock waves, the spatial patterns of which are significantly modified by the relativistic and dissipative effects, may exist. Interestingly, we found that because of ion kinematic viscosity, an initial solitonic profile develops into a shock wave. This later evolves towards a monotonic profile (dissipation–dominant case) as the electrons deviate from their thermodynamic equilibrium. As the relativistic character of the plasma becomes important, the shock wave amplitude decreases. Our investigation may be taken as a prerequisite for the understanding of the shock-waves observed in the ionosphere and the auroral acceleration regions. We recall that when a high energy cosmic ray interacts with the earth’s atmosphere, it may produce an electron–positron pair with enormous velocities. The data obtained during the Alpha Magnetic Spectrometer (AMS) flight permitting to probe the radiation belts in the Earth’s innermost magnetosphere provided an evidence of the presence of positrons.     

Model variables identification of a gas turbine using a subspace approach based on input/output data measurements

This paper deals with a state model identification of a gas turbine used for gas transport, using a subspace approach of the state space model. This method provides a reliable and robust state representation of the model, taking advantage of its benefits in the control, monitoring, and supervision of this machine. The model for each variable is set so that the state matrices associated with the gas turbine model are determined from their real input/output data. The comparison of the obtained identification results with those of the actual turbine operation serves to validate the proposed model in this work. This numerical algorithm of the subspace identification method is full of information and more accurate in terms of residual modeling error, and expresses a very high level of confidence in the identified turbine system dynamics. Hence, the controllability and observability tests of turbine operation for different input/output variables allowed to validate the real-time operating stability of the turbine.     

Adaptive and dual data-communication trust scheme for clustered wireless sensor networks

In wireless sensor networks, trust management schemes are designed to preserve them against misbehavior of malicious sensor nodes. These schemes observe the behavior of nodes, check their conformity to what is expected, compute and assign them trust values, and avoid any interaction with untrustworthy nodes. In this paper, we introduce Adaptive and dual Data-Communication Trust scheme (ADCT) for clustered wireless sensor networks to effectively deal with untrustworthy nodes. Unlike prior works, we propose an adaptive trust function to assess the direct trust between nodes according to the application’s requirement in terms of trust severity. We also consider data trust to cope with untrustworthy nodes during the data collection despite their communication capabilities. Moreover, we use the duality data-communication trust to deal with untrustworthy recommendations when building cluster-member’s feedback at the cluster-head level. Theoretical analysis and simulation show that the trust mechanism presented in this paper provides a better cooperation with the same or even lower communication overhead compared to the latest trust management schemes proposed for clustered wireless sensor networks.     

Gas Turbine Modeling Based on Fuzzy Clustering Algorithm Using Experimental Data

The development of reliable mathematical models for nonlinear systems has been a primary topic in several industrial applications. This work proposes to examine the application of fuzzy logic to represent the control parameters of a gas turbine based on the fuzzy clustering method using Gustafson–Kessel algorithms. The results obtained from data classification of construction with associated models indicate applications in modeling the examined system.     

3-D movement simulation techniques using FE methods: Application to eddy current non-destructive testing

In this paper, sample calculations were performed with a three-dimensional (3-D) numerical method to describe the response of an eddy current (EC) probe to defects in a conducting plate. The governing field equations are given in terms of coupled magnetic vector and electrical scalar potentials and solved using a 3-D finite element method implemented in Matlab environment. The displacement of the sensor operating in absolute or differential mode is simulated using three methods: The first and second methods known, respectively, as the nodal interpolation technique (NIT) and the Lagrange multiplier technique (LMT) consist in ensuring the connection between fixed and moved 3-D independent meshes. The third method known as the properties assignment technique (PAT) is based on the geometrical band.In this work, these methods are used to compute the real and imaginary parts of the impedance correlation at every position of the coil(s). This allows the characterisation of the presence of a defect through the EC distribution.     

Preparation of poly (N,N‐dimethylaminoethyl methacrylate) (PDAEM) membranes: Application for water purification

The present work concerns a development of new membranes for performing ions separation. These membranes were prepared by solution casting followed by solvent evaporation, using a commercial cellulose triacetate (CTA), synthesized poly (N,N‐dimethylaminoethyl methacrylate), macrocylic polyethers (15‐crown‐5 and Dibenzo‐24‐crown‐8) as carrier and dioctylphtalate as plasticizer. Different Polymer Inclusion Membranes were characterized using physical and chemical techniques as well as Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy. Transport of lead and cadmium in aqueous solution has been studied using these systems. The selective separation of these membranes is accomplished by the presence of specific compounds, called carriers, in the membrane phase. The carriers are responsible to facilitate the transport of the target component across selective membranes. The influence of the membrane nature has been studied using some supports of different physical characteristics. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46592.