FEMOSAA: feature-guided and knee-driven multi-objective optimization for self-adaptive software

Self-Adaptive Software (SAS) can reconfigure itself to adapt to the changing environment at runtime, aiming to continually optimize conflicted nonfunctional objectives (e.g., response time, energy consumption, throughput, cost, etc.). In this article, we present Feature-guided and knEe-driven Multi-Objective optimization for Self-Adaptive softwAre (FEMOSAA), a novel framework that automatically synergizes the feature model and Multi-Objective Evolutionary Algorithm (MOEA) to optimize SAS at runtime. FEMOSAA operates in two phases: at design time, FEMOSAA automatically transposes the engineers’ design of SAS, expressed as a feature model, to fit the MOEA, creating new chromosome representation and reproduction operators. At runtime, FEMOSAA utilizes the feature model as domain knowledge to guide the search and further extend the MOEA, providing a larger chance for finding better solutions. In addition, we have designed a new method to search for the knee solutions, which can achieve a balanced tradeoff. We comprehensively evaluated FEMOSAA on two running SAS: One is a highly complex SAS with various adaptable real-world software under the realistic workload trace; another is a service-oriented SAS that can be dynamically composed from services. In particular, we compared the effectiveness and overhead of FEMOSAA against four of its variants and three other search-based frameworks for SAS under various scenarios, including three commonly applied MOEAs, two workload patterns, and diverse conflicting quality objectives. The results reveal the effectiveness of FEMOSAA and its superiority over the others with high statistical significance and nontrivial effect sizes

Deposition Dynamics of Rod-Shaped Colloids during Transport in Porous Media under Favorable Conditions

A three-dimensional computational modeling study of the deposition dynamics of rod-shaped colloids during transport in porous media under favorable conditions (no energy barrier to deposition) is presented. The objective was to explore the influences of the particle shape on colloid transport and retention. During simulation, both translation and rotation of ellipsoidal particles were tracked and evaluated based on an analysis of all forces and torques acting on the particle. We observed that the shape was a key factor affecting colloid transport and attachment. Rod particles exhibited enhanced retention compared with spheres of equivalent volume in the size range greater than ∼200 nm. The shape effect was the most pronounced for particles around 200 nm to 1 μm under simulated conditions. The shape effect was also strongly dependent upon the fluid velocity; it was most significant at high velocity, but not so at very low velocity. The above-described shape effect on retention was directly related to particle rotation dynamics due to the coupled effects from rotational diffusion and flow hydrodynamics. Rotational diffusion changed the particle orientation randomly, which caused the rod particles to drift considerably across flow streamlines for attachment in the size range from 200 nm to 1 μm. The hydrodynamic effect induced periodic particle rotation and oscillation, which rendered large-sized rod particles to behave like “spinning bodies,” prescribed by their long axes so as to easily intercept with the collector surface for retention. Our findings demonstrated that the practice of using equivalent spheres to approximate rods is inadequate in predicting the transport fate and adhesion dynamics of rod-shaped colloids in porous media

Wet-Driven Bionic Actuators from Wool Artificial Yarn Muscles

Nature-similar muscle is one of the ultimate goals of advanced artificial muscle materials. Currently, a variety of chemical and natural materials have been gradually developed for the preparation of artificial muscles. However, due to the scarcity, biological exclusion, and poor flexibility of the abovementioned materials, it is still a challenging process to maximize the imitation of behaviors shown by real muscles and commercial development. Here, this article presents multidimensional wool yarn artificial muscles, and the wet response behavior of fibers is induced in yarn muscles successfully by virtue of weakening the water-repellent effect of wool scales. Wool artificial muscles are cost-effective and widely available and have good biocompatibility. In addition, wool fiber assemblies are structurally stable, soft, and flexible to be processed into artificial muscles with torsional, contractile, and even multilayered structures, enabling various wet-driven behaviors. On the basis of the theoretical model and numerical simulation, we explained and verified the working mechanism employed in wool artificial yarn muscles. Finally, the yarn muscle was integrated into a wool muscle group through the textile technology, followed by the application to robot bionic arms, displaying the great potential of wool artificial yarn muscles in bionic drivers and the intelligent textile industry

Wet-Driven Bionic Actuators from Wool Artificial Yarn Muscles

Nature-similar muscle is one of the ultimate goals of advanced artificial muscle materials. Currently, a variety of chemical and natural materials have been gradually developed for the preparation of artificial muscles. However, due to the scarcity, biological exclusion, and poor flexibility of the abovementioned materials, it is still a challenging process to maximize the imitation of behaviors shown by real muscles and commercial development. Here, this article presents multidimensional wool yarn artificial muscles, and the wet response behavior of fibers is induced in yarn muscles successfully by virtue of weakening the water-repellent effect of wool scales. Wool artificial muscles are cost-effective and widely available and have good biocompatibility. In addition, wool fiber assemblies are structurally stable, soft, and flexible to be processed into artificial muscles with torsional, contractile, and even multilayered structures, enabling various wet-driven behaviors. On the basis of the theoretical model and numerical simulation, we explained and verified the working mechanism employed in wool artificial yarn muscles. Finally, the yarn muscle was integrated into a wool muscle group through the textile technology, followed by the application to robot bionic arms, displaying the great potential of wool artificial yarn muscles in bionic drivers and the intelligent textile industry

Wet-Driven Bionic Actuators from Wool Artificial Yarn Muscles

Nature-similar muscle is one of the ultimate goals of advanced artificial muscle materials. Currently, a variety of chemical and natural materials have been gradually developed for the preparation of artificial muscles. However, due to the scarcity, biological exclusion, and poor flexibility of the abovementioned materials, it is still a challenging process to maximize the imitation of behaviors shown by real muscles and commercial development. Here, this article presents multidimensional wool yarn artificial muscles, and the wet response behavior of fibers is induced in yarn muscles successfully by virtue of weakening the water-repellent effect of wool scales. Wool artificial muscles are cost-effective and widely available and have good biocompatibility. In addition, wool fiber assemblies are structurally stable, soft, and flexible to be processed into artificial muscles with torsional, contractile, and even multilayered structures, enabling various wet-driven behaviors. On the basis of the theoretical model and numerical simulation, we explained and verified the working mechanism employed in wool artificial yarn muscles. Finally, the yarn muscle was integrated into a wool muscle group through the textile technology, followed by the application to robot bionic arms, displaying the great potential of wool artificial yarn muscles in bionic drivers and the intelligent textile industry

Wet-Driven Bionic Actuators from Wool Artificial Yarn Muscles

Nature-similar muscle is one of the ultimate goals of advanced artificial muscle materials. Currently, a variety of chemical and natural materials have been gradually developed for the preparation of artificial muscles. However, due to the scarcity, biological exclusion, and poor flexibility of the abovementioned materials, it is still a challenging process to maximize the imitation of behaviors shown by real muscles and commercial development. Here, this article presents multidimensional wool yarn artificial muscles, and the wet response behavior of fibers is induced in yarn muscles successfully by virtue of weakening the water-repellent effect of wool scales. Wool artificial muscles are cost-effective and widely available and have good biocompatibility. In addition, wool fiber assemblies are structurally stable, soft, and flexible to be processed into artificial muscles with torsional, contractile, and even multilayered structures, enabling various wet-driven behaviors. On the basis of the theoretical model and numerical simulation, we explained and verified the working mechanism employed in wool artificial yarn muscles. Finally, the yarn muscle was integrated into a wool muscle group through the textile technology, followed by the application to robot bionic arms, displaying the great potential of wool artificial yarn muscles in bionic drivers and the intelligent textile industry

Wet-Driven Bionic Actuators from Wool Artificial Yarn Muscles

Nature-similar muscle is one of the ultimate goals of advanced artificial muscle materials. Currently, a variety of chemical and natural materials have been gradually developed for the preparation of artificial muscles. However, due to the scarcity, biological exclusion, and poor flexibility of the abovementioned materials, it is still a challenging process to maximize the imitation of behaviors shown by real muscles and commercial development. Here, this article presents multidimensional wool yarn artificial muscles, and the wet response behavior of fibers is induced in yarn muscles successfully by virtue of weakening the water-repellent effect of wool scales. Wool artificial muscles are cost-effective and widely available and have good biocompatibility. In addition, wool fiber assemblies are structurally stable, soft, and flexible to be processed into artificial muscles with torsional, contractile, and even multilayered structures, enabling various wet-driven behaviors. On the basis of the theoretical model and numerical simulation, we explained and verified the working mechanism employed in wool artificial yarn muscles. Finally, the yarn muscle was integrated into a wool muscle group through the textile technology, followed by the application to robot bionic arms, displaying the great potential of wool artificial yarn muscles in bionic drivers and the intelligent textile industry

Multifunctional Tin-Based Heterogeneous Catalyst for Catalytic Conversion of Glucose to 5‑Hydroxymethylfurfural

Using 5-sulfoisophthalic acid as the ligand, tin porous coordination polymer (SnPCP) was synthesized on polydopamine-coated MnO₂ (MnO₂<b>–</b>PDA). The novel composite SnPCP@MnO₂<b>–</b>PDA was used for conversion of glucose into 5-hydroxymethylfurfural (HMF). The tetrahedral-coordinated tin and the sulfonic groups of the ligand catalyze glucose isomerization to fructose and fructose dehydration to HMF, respectively. Thus, the composite is a bifunctional catalyst. The porous structure of SnPCP of the composite facilitates the transport of glucose, intermediate, and HMF within the catalyst. In addition, MnO₂<b>–</b>PDA was found to be able to catalyze the conversion of glucose to HMF. The synergistic effect of SnPCP and MnO₂<b>–</b>PDA achieved HMF yields of 55.8% in DMSO and 41.2% in water/THF. Consecutive use of SnPCP@MnO₂<b>–</b>PDA demonstrated that, after 5 cycles, the activity loss is not significant in terms of the HMF yield and glucose conversion

Synthesis of Dibenzothiophene and 1,4-Dihydrodibenzothiophene Derivatives via Allylic Phosphonium Salt Initiated Domino Reactions

Two efficient synthetic protocols were developed for the synthesis of dibenzothiophene and 1,4-dihydrodibenzothiophene using thioaurones and allylic phosphonium salt. Mild reaction conditions, a one-pot procedure, and easily accessible starting materials make these protocols powerful tools for the synthesis of these compounds, which are often used in material and pharmaceutical sciences

Mixtures of Two Bile Alcohol Sulfates Function as a Proximity Pheromone in Sea Lamprey

<div><p>Unique mixtures of pheromone components are commonly identified in insects, and have been shown to increase attractiveness towards conspecifics when reconstructed at the natural ratio released by the signaler. In previous field studies of pheromones that attract female sea lamprey (<i>Petromyzon marinus</i>, L.), putative components of the male-released mating pheromone included the newly described bile alcohol 3,12-diketo-4,6-petromyzonene-24-sulfate (DkPES) and the well characterized 3-keto petromyzonol sulfate (3kPZS). Here, we show chemical evidence that unequivocally confirms the elucidated structure of DkPES, electrophysiological evidence that each component is independently detected by the olfactory epithelium, and behavioral evidence that mature female sea lamprey prefer artificial nests activated with a mixture that reconstructs the male-released component ratio of 30:1 (3kPZS:DkPES, molar:molar). In addition, we characterize search behavior (sinuosity of swim paths) of females approaching ratio treatment sources. These results suggest unique pheromone ratios may underlie reproductive isolating mechanisms in vertebrates, as well as provide utility in pheromone-integrated control of invasive sea lamprey in the Great Lakes.</p></div