390 research outputs found
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
Table_1_Knowledge, attitude, and practice of atrial fibrillation in high altitude areas.docx
BackgroundTo investigate the knowledge, attitude, and practice (KAP) of atrial fibrillation (AF) among the general population in high-altitude areas.MethodologyA web-based cross-sectional study was conducted among the general population in high-altitude areas.ResultsA total of 786 valid questionnaires were enrolled, with a mean age of 34.75 ± 14.16 years. The mean score of knowledge, attitude and practice were 8.22 ± 6.50 (possible range: 0–10), 28.90 ± 5.63 (possible range: 8–40), 34.34 ± 6.44 (possible range: 9–45), respectively. The multivariate analysis showed that knowledge scores (OR = 1.108, 95% CI = 1.075–1.142, p ConclusionThe general population in high-altitude regions had adequate knowledge, positive attitude, and proactive practice towards AF. The SEM was suitable for explaining general population’ KAP regarding AF, revealing that knowledge directly and positively affected attitude and practice.</p
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
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
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 MnO<sub>2</sub> (MnO<sub>2</sub><b>–</b>PDA). The novel composite SnPCP@MnO<sub>2</sub><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, MnO<sub>2</sub><b>–</b>PDA was found to be able to catalyze the conversion of glucose to
HMF. The synergistic effect of SnPCP and MnO<sub>2</sub><b>–</b>PDA achieved HMF yields of 55.8% in DMSO and 41.2% in water/THF.
Consecutive use of SnPCP@MnO<sub>2</sub><b>–</b>PDA demonstrated
that, after 5 cycles, the activity loss is not significant in terms
of the HMF yield and glucose conversion
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