Balancing Exploration and Exploitation With Decomposition-Based Dynamic Multi-Objective Evolutionary Algorithm

Balancing exploration and exploitation is a crucial issue in evolutionary global optimization. This paper proposes a decomposition-based dynamic multi-objective evolutionary algorithm for addressing global optimization problems. In the proposed method, the niche count function is regarded as a helper objective to maintain the population diversity, which converts a global optimization problem to a multi-objective optimization problem (MOP). The niche-count value is controlled by the niche radius. In the early stage of evolution, a large niche radius promotes the population diversity for better exploration; in the later stage of evolution, a niche radius close to 0 focuses on convergence for better exploitation. Through the whole evolution process, the niche radius is dynamically decreased from a large value to zero, which can provide a sound balance between the exploration and exploitation. Experimental results on CEC 2014 benchmark problems reveal that the proposed algorithm is capable of offering high-quality solutions, in comparison with four state-of-the-art algorithms.

Balancing Exploration and Exploitation with Decomposition-Based Dynamic Multi-objective Evolutionary Algorithm

Balancing exploration and exploitation is a crucial issue in evolutionary global optimization. This paper proposes a decomposition-based dynamic multi-objective evolutionary algorithm for addressing global optimization problems. In the proposed method, the niche count function is regarded as a helper objective to maintain the population diversity, which converts a global optimization problem to a multi-objective optimization problem (MOP). The niche-count value is controlled by the niche radius. In the early stage of evolution, a large niche radius promotes the population diversity for better exploration; in the later stage of evolution, a niche radius close to 0 focuses on convergence for better exploitation. Through the whole evolution process, the niche radius is dynamically decreased from a large value to zero, which can provide a sound balance between the exploration and exploitation. Experimental results on CEC 2014 benchmark problems reveal that the proposed algorithm is capable of offering high-quality solutions, in comparison with four state-of-the-art algorithms.

Mode count and modal density of nonsymmetric cross-ply laminated composite beams

Fiber-reinforced composites are used in many weight critical applications owing to their high strength-to-weight and stiffness-to-weight ratios. In certain applications, fiber-reinforced composites are subjected to broadband excitation sources that act over a significant portion of the audible frequency range leading to the response of a large number of higher order structural modes. In predicting the response levels of such systems, regardless of whether it is modeled in isolation or using a statistical energy analysis framework, it becomes necessary to quantify the number of resonant modes available to receive and store energy within a frequency band. Conventionally, the mode count and modal density are two parameters used for this purpose. Generally, the analysis of the mode count and modal density of anisotropic fiber-reinforced composite structures have received considerably less attention compared to their isotropic metallic counterparts, and as a result a number of key analytical formulations are yet to be derived and investigated. In this work, the modal distribution and density of nonsymmetric cross-ply laminated composite beams coupled in bending and longitudinal extension are analyzed. A wave approach is used to derive an expression for the mode count of the beam having generalized boundary conditions. Using numerical examples and nonlinear regression analysis, simplified expressions are then obtained for the average mode count function of the beam for different boundary conditions. An analytical expression for the modal density is obtained by taking the differential of the average mode count function with respect to frequency. The wave approach employed in this study is validated based on comparison with results from past literature in addition to finite element simulations. The expression for the modal density is also validated using a finite element model and is shown to be independent of boundary conditions.

Platelet Count and Function during Pediatric Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is a form of life support used to treat neonates, children, and adults with cardiorespiratory failure refractory to conventional therapy. This therapy requires the use of anticoagulation to prevent clotting in the extracorporeal circuit, but anticoagulation also increases the risk of bleeding on ECMO. Both bleeding and thrombosis remain significant complications on ECMO and balancing these risks is challenging. Acquired platelet dysfunction is common during ECMO and quantitative and qualitative platelet dysfunction contributes to bleeding risk. Optimal platelet count, function, and transfusion thresholds are not well established during pediatric ECMO. In this review, we provide an overview of hemostatic alterations during ECMO, changes in platelet count and function, platelet monitoring techniques, bleeding risk, and future needs to best optimize patient management and care.

Results on Functions on Dedekind Multisets

Many real-life problems are well represented only by sets which allow repetition(s), such as the multiset. Although not limited to the following, such cases may arise in a database query, chemical structures and computer programming. The set of roots of a polynomial, say f ( x ) , has been found to correspond to a multiset, say F. If f ( x ) and g ( x ) are polynomials whose sets of roots respectively correspond to the multisets F ( x ) and G ( x ) , the set of roots of their product, f ( x ) g ( x ) , corresponds to the multiset F ⊎ G , which is the sum of multisets F and G. In this paper, some properties of the algebraic sum of multisets ⊎ and some results on selection are established. Also, the count function of the image of any function on Dedekind multisets is defined and some of its properties are established. Some applications of these multisets are also given.

DERIVWWW - WEB-BASED SYMBOLIC DIFFERENTIATION SYSTEM

The article presents an online system for symbolic differentiation. It shows how derivatives are calculated. The trees are used for internal representation of formulas. Derivatives are generated by tree transformations. Presented algorithms are part of the microsystems simulator Dero. They are required by the calculation algorithms such as Newton-Raphson. They can be used to generate derivatives in model description languages and for automatic derivative calculation. DerivWWW can be used in didactics. The system can serve as a tool for students to count function derivatives at the point. It can also be used in teaching on the technical fields of study. Symbolic derivatives are saved in the Tex format, allowing easy integration with other software. The developed and implemented algorithms are discussed. Examples of use are given.

Vertebral Artery Thrombosis in Chronic Idiopathic Thrombocytopenic Purpura

Introduction. Immune thrombocytopenic purpura (ITP) is an autoimmune hematological disorder that causes decreased production and destruction of platelets leading to thrombocytopenia. Although thrombocytopenia usually causes hemorrhagic problems, thrombotic events like strokes, although rare, can still occur. Management of thrombotic events in patients with ITP differs from that of patients with normal platelet count function and count. Case Description. A 32-year-old female with a history of ITP presented with ischemic stroke. The patient was treated in the hospital with IV immunoglobulin, discharged to a rehabilitation facility, and had complete resolution of symptoms when examined at a follow-up visit 3 months later. Conclusion. Although stroke in patients with ITP is very rare due to thrombocytopenia, it has been reported in several other published cases and is likely associated with increased platelet microparticle levels, a byproduct of platelet destruction. While usage of antiplatelet therapy in such patients is debated, immunosuppression therapy has been the mainstay treatment in all published cases.