Uncertainty And Evolutionary Optimization: A Novel Approach

Evolutionary algorithms (EA) have been widely accepted as efficient solvers for complex real world optimization problems, including engineering optimization. However, real world optimization problems often involve uncertain environment including noisy and/or dynamic environments, which pose major challenges to EA-based optimization. The presence of noise interferes with the evaluation and the selection process of EA, and thus adversely affects its performance. In addition, as presence of noise poses challenges to the evaluation of the fitness function, it may need to be estimated instead of being evaluated. Several existing approaches attempt to address this problem, such as introduction of diversity (hyper mutation, random immigrants, special operators) or incorporation of memory of the past (diploidy, case based memory). However, these approaches fail to adequately address the problem. In this paper we propose a Distributed Population Switching Evolutionary Algorithm (DPSEA) method that addresses optimization of functions with noisy fitness using a distributed population switching architecture, to simulate a distributed self-adaptive memory of the solution space. Local regression is used in the pseudo-populations to estimate the fitness. Successful applications to benchmark test problems ascertain the proposed method's superior performance in terms of both robustness and accuracy.Comment: In Proceedings of the The 9th IEEE Conference on Industrial Electronics and Applications (ICIEA 2014), IEEE Press, pp. 988-983, 201

Formula SAE Intake System

The Formula SAE Intake System is intended to optimize the airflow into a restricted 600cc engine. The intake system is designed, fabricated, and installed in accordance with the FSAE rule book with a focus on maximizing the vehicle’s acceleration. It is directly responsible for determining the drivability of the car and how much horsepower the flow restricted engine produces. Design of the intake was conceptualized based on researching a number of factors including venturi diffusion angles, plenum volumes, and runner lengths. Initial tests were performed utilizing computational fluid dynamics for a total of 367 flow simulations and 261 running hours on various intake components in SolidWorks Flow Simulation 2016. From the beginning, it was known that the intake needed to possess certain contours that would be very difficult to create with sheet metal. It was for this reason that a composite construction was pursued for the plenum of the intake manifold, utilizing fused deposition modeling to form the mold. Flow testing and dynamometer testing will be utilized to verify the effectiveness of the design. In the end, the intake system will provide peak performance in the flow restricted system. The increased brake horsepower and improved vehicle drivability will provide a competitive advantage on any race course.https://scholarscompass.vcu.edu/capstone/1198/thumbnail.jp

Faunal diversity of Paederus Fabricius, 1775 (Coleoptera: Staphylinidae) in Iran

Beetles of the genus Paederus sensu stricto Fabricius, 1775 (Coleoptera: Staphylinidae) are often noticed because of their potency in inducing a dermal lesion, so-called linear dermatitis. This genus, which is placed in the tribe Paederini and subfamily Paederinae of Staphylinidae, currently comprises 490 species worldwide. Our study presents a short review of the former records of Paederus spp. in Iran plus some unpublished data. Field collections were done during March-October yearly (1997-2007) in northern and southern Iran and April-June from central, eastern, western and north-western Iran (2008-2009). The present study adds four species to the Iranian fauna of the genus Paederus, which are P. brevipennis Lacordaire, 1835, P. basalis Bernhauer, 1914, P. pubescens Cameron, 1914 and P. schoenherri Czwalina, 1899. Paederus brevipennis and P. schoenherri are the first members of the subgenus Harpopaederus Scheerpeltz, 1957, ever reported from Iran. Considering previous reports, museum-deposited materials and our findings, 14 species and subspecies of the genus Paederus, which are grouped in five subgenera, occur in Iran. These subgenera are Eopaederus Scheerpeltz, Harpopaederus Scheerpeltz, Heteropaederus Scheerpeltz, Paederus Fabricius and Poederomorphus des Cottes; however P. duplex spectabilis Bernhauer, 1913 is not yet attributed to any of the 13 so-far defined subgenera

A multilevel approach for obtaining locally optimal finite element meshes

In this paper we consider the adaptive finite element solution of a general class of variational problems using a combination of node insertion, node movement and edge swapping. The adaptive strategy that is proposed is based upon the construction of a hierarchy of locally optimal meshes starting with a coarse grid for which the location and connectivity of the nodes is optimized. This grid is then locally refined and the new mesh is optimized in the same manner. Results presented indicate that this approach is able to produce better meshes than those possible by more conventional adaptive strategies and in a relatively efficient manner

A moving-mesh finite element method and its application to the numerical solution of phase-change problems

A distributed Lagrangian moving-mesh finite element method is applied to problems involving changes of phase. The algorithm uses a distributed conservation principle to determine nodal mesh velocities, which are then used to move the nodes. The nodal values are obtained from an ALE (Arbitrary Lagrangian-Eulerian) equation, which represents a generalization of the original algorithm presented in Applied Numerical Mathematics, 54:450--469 (2005). Having described the details of the generalized algorithm it is validated on two test cases from the original paper and is then applied to one-phase and, for the first time, two-phase Stefan problems in one and two space dimensions, paying particular attention to the implementation of the interface boundary conditions. Results are presented to demonstrate the accuracy and the effectiveness of the method, including comparisons against analytical solutions where available

Homogeneous alignment of nematic liquid crystals by ion beam etched surfaces

A wide range of ion beam etch parameters capable of producing uniform homogeneous alignment of nematic liquid crystals on SiO2 films are discussed. The alignment surfaces were generated by obliquely incident (angles of 5 to 25 deg) argon ions with energies in the range of 0.5 to 2.0 KeV, ion current densities of 0.1 to 0.6 mA sq cm and etch times of 1 to 9 min. A smaller range of ion beam parameters (2.0 KeV, 0.2 mA sq cm, 5 to 10 deg and 1 to 5 min.) were also investigated with ZrO2 films and found suitable for homogeneous alignment. Extinction ratios were very high (1000), twist angles were small ( or = 3 deg) and tilt-bias angles very small ( or = 1 deg). Preliminary scanning electron microscopy results indicate a parallel oriented surface structure on the ion beam etched surfaces which may determine alignment

Spectral Engineering of Slow Light, Cavity Line Narrowing, and Pulse Compression

More than 4 orders of magnitude of cavity-linewidth narrowing in a rare-earth-ion-doped crystal cavity, emanating from strong intracavity dispersion caused by off-resonant interaction with dopant ions, is demonstrated. The dispersion profiles are engineered using optical pumping techniques creating significant semipermanent but reprogrammable changes of the rare-earth absorption profiles. Several cavity modes are shown within the spectral transmission window. Several possible applications of this phenomenon are discussed.Comment: arXiv admin note: substantial text overlap with arXiv:1304.445

Inducible Protective Processes in Animal Systems .5. Clastogenic Adaptation Triggered by Low-Dose of Methyl Methanesulfonate (Mms) in Poecilocerus-Pictus

The monofunctional alkylating agent methyl methanesulfonate (MMS) was used to study the induction of inducible protective processes (clastogenic adaptation) in meiotic cells of the grasshopper, Poecilocerus pictus. After a low (conditioning) dose of 0.012 M and challenging with a high (challenging) dose of 0.048 M MMS after 2 h time-lag, the incidence of chromosomal anomalies in metaphase I, II and anaphase I and II stages was found to be significantly less (P < 0.05) compared to that of the additive effect of both the conditioning and the challenging doses. The data suggest that the low dose of MMS rendered the meiotic cells more resistant to the clastogenic effects of a subsequent high dose of MMS employed. These results lend further support to the earlier report from the same laboratory where a low dose of ethyl methanesulfonate (EMS) was found to render protection against a high dose of the same clastogen in meiotic cells of P. pictus. Furthermore, it is clear from the results that conditioning by the methylating (MMS) agent in cells is less effective in comparison with that of the ethylating (EMS) agent