Abstract-The nematode Caenorhabditis Elegans has become an important model organism for many areas of biological research including genetics, development, and neurobiology. It is the first organism to have its genome sequenced, complete cell ontogeny determined, and nervous system mapped. With all of the information that is available on this simple organism, C. elegans may also become the first organism to be accurately and completely modeled in silico.In this work we take a step toward this goal by presenting a biologically accurate, 3-dimensional model of C. elegans. This model takes into account many facets of the organism including size, shape, weight distribution, muscle placement, and muscle force. We also explicitly model the environment of the worm to include factors such as contact, friction, inertia, and gravity.We tuned and validated our model using video recordings taken of the worm and show that our model accurately depicts the physics of undulatory locomotion used to forward crawl on an agarose surface. We also present evidence that suggests that the forces applied by the nematode during locomotion are not uniform, but decrease as the wave is propagated from its head to its tail.
Dynamic, partial centralization has received a considerable amount of attention in the distributed problem solving community. As the name implies, this technique works by dynamically identifying portions of a shared problem to centralize in order to speed the problem solving process. Currently, a number of algorithms have been created which employ this simple, yet powerful technique to solve problems such as distributed constraint satisfaction (DCSP), distributed constraint optimization (DCOP), and distributed resource allocation.In fact, one such algorithm, Asynchronous Partial Overlay (APO), was shown to outperform the Asynchronous Weak Commitment (AWC) protocol, which is one of the best known methods for solving DCSPs. One of the key differences between these two algorithms is that APO, as part of the centralization process, uses explicit constraint passing. AWC, on the other hand, passed nogoods because it tries to provide security and privacy. Because of these differences in underlying assumptions, a number of researchers have criticized the comparison between these two protocols.This paper attempts to resolve this disparity by introducing a new AWC/APO algorithm called Nogood-APO that like AWC uses nogood passing to provide security and privacy and like APO uses dynamic partial centralization to speed the problem solving process. Like its parent algorithms, this new protocol is sound and complete and performs nearly as well as APO, while still outperforming AWC, on distributed 3-coloring problems. In addition, this paper shows that Nogood-APO provides more privacy to the agents than both APO and AWC on all but the sparsest problems. These findings demonstrate that a dynamic, partial centralization-based protocol can provide privacy and that even when operating with the same assumptions as AWC still solves problems in fewer cycles using less computation and communication..
Residual stresses are inherent in thermal barrier coatings (TBC's) and can influence in-service performance and life of the coatings. Therefore, the effective design and processing of TBC's requires knowledge about residual stress generation and the effect of residual stresses on TEC life. Understanding residual stress generation and the effects on thermal barrier coating life are formidable tasks that have received little attention in the literature. This work addresses the first task. Specifically, the objectives of this work were to better understand how processing and post-processing residual stresses are generated in TBC's. The approach was to evaluate the effect of substrate temperature during processing and the effect of post-processing thermal cycling on the generation of coating residual stresses. Residual stress measurements were conducted using an experimental residual stress evaluation technique called the "Modified Layer Removal Method." Results showed residual stresses could be changed both by controlling the substrate temperature during processing and by thermal cycling after processing. Residual stresses in specimens with a higher substrate temperature during processing were found to be more compressive than residual stresses in specimens with a lower processing substrate temperature. Post-processing thermal cycling caused the residual stresses to become more compressive for specimens with both the higher and lower substrate processing temperatures. Residual stresses for one and ten post-processing thermal cycles were evaluated. For both substrate processing temperatures, the change in TBC compressive residual stresses for the first cycle was more than three times the total residual stress change that occurred in cycles two through ten. Interestingly, the increase in residual stresses in cycles two through ten for the higher substrate processing temperature was greater than that for the lower processing substrate temperature. In other words, based on results obtained here, compressive residual stresses generated during thermal cycling appear to depend on the existing processing residual stress. For these conditions, higher processing compressive residual stresses lead to higher post-processing changes in compressive stresses per thermal cycle.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.