Cellular Harmony Search for Optimization Problems

Structured population in evolutionary algorithms (EAs) is an important research track where an individual only interacts with its neighboring individuals in the breeding step. The main rationale behind this is to provide a high level of diversity to overcome the genetic drift. Cellular automata concepts have been embedded to the process of EA in order to provide a decentralized method in order to preserve the population structure. Harmony search (HS) is a recent EA that considers the whole individuals in the breeding step. In this paper, the cellular automata concepts are embedded into the HS algorithm to come up with a new version called cellular harmony search (cHS). In cHS, the population is arranged as a two-dimensional toroidal grid, where each individual in the grid is a cell and only interacts with its neighbors.Thememory consideration and population update aremodified according to cellular EA theory. The experimental results using benchmark functions show that embedding the cellular automata concepts with HS processes directly affects the performance. Finally, a parameter sensitivity analysis of the cHS variation is analyzed and a comparative evaluation shows the success of cHS

Study of the influence of normal and high blood pressure on normal and stenosed carotid bifurcation using fluid-structure interaction

Atherosclerosis (stenosis) is a common cardiovascular disease in which the blood vessel restructures by narrowing, thickening and gets hardened due to the deposition of plaque. A detailed study of narrowing of arteries applying computational aspects which leads to better findings in order to know the underlying mechanics of development and progression of such diseases. Such kind of analysis can be a useful tool for the medical professionals to study the realistic physiological conditions. They can simulate and observe the blood flow in arteries. In the present study, a case of normal and stenosed carotid bifurcation is simulated. The models are generated in CATIA based on the clinical data obtained from a patient using Ultrasound Doppler. A transient FSI analysis considering Newtonian behavior is performed to compare the significance of High Blood Pressure (HBP) and Normal Blood Pressure (NBP) on carotid bifurcation. The FSI simulation is carried out for both HBP and NBP conditions for several pulse cycles on normal and stenosed models using ANSYS13.0 to demonstrate the changes in flow behavior at various sections of the model. The computed results agree well with clinical observations and available literature as seen in case of NBP

Experimental and numerical study of stenotic flows

Atherosclerosis has been leading cause of deaths in several countries. Recent technical advances have allowed the investigation of stenotic flows and in understanding the implications with increased severity. Such studies shall provide detailed understanding of flow across stenosis and its progression. In the present study, a large artery representing segment of aorta is considered as test specimen. Experimental study is carried out by generating the pulsatile flow through pulsatile duplicator. Flow across normal and various severities of stenosis such as 25%, 50% and 75% are studied. Numerical simulation using CFD is also carried out in similar normal and stenosed models. A novel concept of using pulse duplicator to generate pulsatile waves and investigate the different stenosed models has been adopted. Results obtained experimentally and numerically are compared and agree well with that of clinical observations. This study demonstrates significant variation of haemodynamic in post-stenotic region with increased stenosis. Increased pulse pressure, phase lag is observed with increased severity. It is also observed that stenosis greater than 75% is significant as flow complexity is induced with considerable disturbance even in early and latter part of pulse cycle. Such study shall be useful in understanding the flow changes in stenosis and enhance clinical observation

Fluid-structure interaction study of stenotic flow in subject specific carotid bifurcation: a case study

Advances in numerical simulation have allowed the investigation of complex interaction of blood flow through elastic arteries which can be useful in demonstrating the disease progression and haemodynamics of cardiovascular diseases such as atherosclerosis. In the present study, patient is diagnosed with an occluded right Internal Carotid Artery (ICA) with partial stenosis at root of right External Carotid Artery (ECA) and partial stenosis at the root of left ICA. 3D patient specific carotid bifurcation is generated based on CT scan data using MIMICS-14.0 and numerical analysis is performed using FSI in ANSYS-14.5. The blood flow is assumed to be incompressible, homogenous and Newtonian, while artery wall is assumed to behave linearly elastic. The two-way sequentially coupled transient FSI analysis is performed using FSI solver for three pulse cycles and haemodynamic parameters such as flow pattern, Wall Shear Stress (WSS), pressure contours and arterial wall deformation are studied at the bifurcation and critical zones. The variation in flow behavior is investigated throughout the pulse and simulation results obtained reveals that there is a considerable increase in the flow behavior in partially stenosed carotid unlike occluded carotid. The investigation also demonstrates disturbed flow pattern especially at the bifurcation and stenosed zone elevating the haemodynamic variation during peak systole and later part of pulse cycle. The obtained results agree well with the clinical observation and demonstrate the potential of patient specific numerical studies in prognosis of disease progression and plaque rupture

A computational solution of the multi-term nonlinear ODEs with variable coefficients using the integral-collocation-approach based on Legendre polynomials

The main aim of this work is devoted to propose and analyze some schemes of the integral collocation formulation dependent on Legendre polynomials. We introduce these formulae to solve the multi-term ODEs with variable coefficients. The proposed technique is used to reduce the given problem to solve a system of algebraic equations. Numerical results are given to satisfy the accuracy and the applicability of the implemented approach

Multimodality and Nonrigid Image Registration with Application to Diffusion Tensor Imaging

The great challenge in image registration is to devise computationally efficient algorithms for aligning images so that their details overlap accurately. The first problem addressed in this thesis is multimodality medical image registration, which we formulate as an optimization problem in the information-theoretic setting. We introduce a viable and practical image registration method by maximizing a generalized entropic dissimilarity measure using a modified simultaneous perturbation stochastic approximation algorithm. The feasibility of the proposed image registration approach is demonstrated through extensive experiments. The rest of the thesis is devoted to nonrigid medical image registration. We propose an informationtheoretic framework by optimizing a non-extensive entropic similarity measure using the quasi-Newton method as an optimization scheme and cubic B-splines for modeling the nonrigid deformation field between the fixed and moving 3D image pairs. To achieve a compromise between the nonrigid registration accuracy and the associated computational cost, we implement a three-level hierarchical multi-resolution approach in such a way that the image resolution is increased in a coarse to fine fashion. The feasibility and registration accuracy of the proposed method are demonstrated through experimental results on a 3D magnetic resonance data volume and also on clinically acquired 4D computed tomography image data sets. In the same vein, we extend our nonrigid registration approach to align diffusion tensor images for multiple components by enabling explicit optimization of tensor reorientation. Incorporating tensor reorientation in the registration algorithm is pivotal in wrapping diffusion tensor images. Experimental results on diffusion-tensor image registration indicate the feasibility of the proposed approach and a much better performance compared to the affine registration method based on mutual information, not only in terms of registration accuracy in the presence of geometric distortions but also in terms of robustness in the presence of Rician noise

Metabolic Syndrome and Its Individual Components among Jordanian Children and Adolescents

This study aimed to determine the prevalence of metabolic syndrome (MeS) and its individual components in Jordanian children and adolescents aged 7–18 years and determine the factors that are associated with clustering of metabolic abnormalities. MeS was defined using the International Diabetes Federation (IDF) definition. The prevalence of MeS was estimated from 512 subjects who had complete information on all MeS components. The prevalence of MeS according to IDF criteria was 1.4% in subjects aged between 10 and 15.9 years and 3.6% in subjects aged between 16 and 18 years. When categorized according to body mass index (BMI), the prevalence of the MeS was 15.1% in obese subjects, compared to 0.3% in subjects with normal BMI, and 3.0% in overweight subjects. In conclusion, our results indicate that although the prevalence of MeS is low in Jordanian children and adolescents, a large proportion of them had one or two metabolic abnormalities

Chemical, physical, microbiological and quality attributes studies on River Nile crayfish

In Egypt, red crayfish has become an important new food source, a cheap and popular source of aquatic food, replacing the expensive marine crustaceans. Chemical, physical, microbiological and quality attributes of red crayfish samples were determined. Results show that total weight of inedible parts was 84.64% of the live weight. Value of raw fresh crayfish yield was higher than that boiled. Cooking loss tail meat for boiled crayfish was 33.88% of meat. Moisture, protein and ash contents of raw fresh red crayfish (%) were slightly higher than those of boiled, while fat, fiber and carbohydrates contents (%) were higher than those of raw fresh. Crayfish is considered as a good source for minerals. Amino acids content for raw fresh crayfish was relatively high and the reverse was recorded for boiled crayfish. In conclusion, the boiled red crayfish had better quality attributes than that of raw fresh.Keywords: Red swamp crayfish, chemical composition, physical properties, microbiological aspects and quality attribute