658 research outputs found
Sparse Localization with a Mobile Beacon Based on LU Decomposition in Wireless Sensor Networks
Node localization is the core in wireless sensor network. It can be solved by powerful beacons, which are equipped with global positioning system devices to know their location information. In this article, we present a novel sparse localization approach with a mobile beacon based on LU decomposition. Our scheme firstly translates node localization problem into a 1-sparse vector recovery problem by establishing sparse localization model. Then, LU decomposition pre-processing is adopted to solve the problem that measurement matrix does not meet the re¬stricted isometry property. Later, the 1-sparse vector can be exactly recovered by compressive sensing. Finally, as the 1-sparse vector is approximate sparse, weighted Cen¬troid scheme is introduced to accurately locate the node. Simulation and analysis show that our scheme has better localization performance and lower requirement for the mobile beacon than MAP+GC, MAP-M, and MAP-M&N schemes. In addition, the obstacles and DOI have little effect on the novel scheme, and it has great localization performance under low SNR, thus, the scheme proposed is robust
Constructing Intercultural Communicative Competence Framework for English Learners
Intercultural communicative competence (ICC) is an area of research that has tremendous pragmatic potential. Many teachers and English learners have noticed that English education is both instrumental and humanistic in nature. Thus, the ultimate goal of English teaching is intended to cultivate the intercultural communicative competence. This goal has gathered a widespread attention. Thus, to study intercultural communicative competence is of great significance in the field of intercultural communication. However, the research on this competence is limited. Thus, an effective training framework is yet to be constructed. There is no universally agreed-upon definition of intercultural communicative competence. Therefore, the present review is intended to introduce the framework of intercultural communicative competence in College English. In this review, we will pay attention to what intercultural communicative competence is and how to construct intercultural communicative competence framework for English learners, which may be useful for English learners to communicate more effectively with people from other cultures
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A Study on Nonthermal Irreversible Electroporation of the Thyroid.
BackgroundNonthermal irreversible electroporation is a minimally invasive surgery technology that employs high and brief electric fields to ablate undesirable tissues. Nonthermal irreversible electroporation can ablate only cells while preserving intact functional properties of the extracellular structures. Therefore, nonthermal irreversible electroporation can be used to ablate tissues safely near large blood vessels, the esophagus, or nerves. This suggests that it could be used for thyroid ablation abutting the esophagus. This study examines the feasibility of using nonthermal irreversible electroporation for thyroid ablation.MethodsRats were used to evaluate the effects of nonthermal irreversible electroporation on the thyroid. The procedure entails the delivery of high electric field pulses (1-3 kV/cm, 100 microseconds) between 2 surface electrodes bracing the thyroid. The right lobe was treated with various nonthermal irreversible electroporation pulse sequences, and the left was the control. After 24 hours of the nonthermal irreversible electroporation treatment, the thyroid was examined with hemotoxylin and eosin histological analysis. Mathematical models of electric fields and the Joule heating-induced temperature raise in the thyroid were developed to examine the experimental results.ResultsTreatment with nonthermal irreversible electroporation leads to follicular cells damage, associated with cell swelling, inflammatory cell infiltration, and cell ablation. Nonthermal irreversible electroporation spares the trachea structure. Unusually high electric fields, for these types of tissue, 3000 V/cm, are needed for thyroid ablation. The mathematical model suggests that this may be related to the heterogeneous structure of the thyroid-induced distortion of local electric fields. Moreover, most of the tissue does not experience thermal damage inducing temperature elevation. However, the heterogeneous structure of the thyroid may cause local hot spots with the potential for local thermal damage.ConclusionNonthermal irreversible electroporation with 3000 V/cm can be used for thyroid ablation. Possible applications are treatment of hyperthyroidism and thyroid cancer. The highly heterogeneous structure of the thyroid distorts the electric fields and temperature distribution in the thyroid must be considered when designing treatment protocols for this tissue type
A Novel Admission Control Model in Cloud Computing
With the rapid development of Cloud computing technologies and wide adopt of
Cloud services and applications, QoS provisioning in Clouds becomes an
important research topic. In this paper, we propose an admission control
mechanism for Cloud computing. In particular we consider the high volume of
simultaneous requests for Cloud services and develop admission control for
aggregated traffic flows to address this challenge. By employ network calculus,
we determine effective bandwidth for aggregate flow, which is used for making
admission control decision. In order to improve network resource allocation
while achieving Cloud service QoS, we investigate the relationship between
effective bandwidth and equivalent capacity. We have also conducted extensive
experiments to evaluate performance of the proposed admission control
mechanism
Melt crystallization and segmental dynamics of poly(ethylene oxide) confined in a solid electrolyte composite
The isothermal melt crystallization and the corresponding segmental dynamics, of a high molecular weight poly(ethylene oxide) (PEO) confined by Li7La3Zr2O12 (LLZO) particles in solid electrolyte composites, were monitored by differential scanning calorimetry (DSC) and dielectric relaxation spectroscopy (DRS), respectively. Our results show that the overall crystallinity is positively correlated with the surface area of LLZO particles. The primary and secondary crystallization processes are identified by a modified Avrami equation, while two dynamic modes, the α relaxation and α′ relaxation, were in the DRS measurements. The results reveal an unambiguous correlation between the primary crystallization and the α relaxation, while a correlation between the second crystallization and the α′ relaxation concurrently exist in the electrolyte composites. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 466–477In a representative polymer‐ceramic composite solid electrolyte, segmental dynamics are closely related to the crystallization processes in the polymer matrix. This nature may significantly impact the performance of the electrolyte, as ionic conductivity in such material relies on segmental motions of the polymer.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153736/1/pola29577_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153736/2/pola29577.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153736/3/pola29577-sup-0001-AppendixS1.pd
Optimal Control of Heat Engines in Non-equilibrium Statistical Mechanics
A heat engine is a cyclically operated statistical mechanical system which converts heat supply from a heat bath into mechanical work. The heat engine is operated by varying the system parameter. As it is operated in finite time, this non-equilibrium statistical mechanical system is a dissipative system. In this dissertation, our research focuses on two heat engines: one is a stochastic oscillator and the other is a capacitor connected to a Nyquist-Johnson resistor (a stochastically driven resistor-capacitor circuit). In the stochastic oscillator, by varying the stiffness of the potential well, the system can convert heat to mechanical work. In the resistor-capacitor circuit, the output of mechanical work is due to the change of the capacitance of the capacitor. These two heat engines are parametrically-controlled. A path in the parameter space of a heat engine is termed as a protocol.
In the first chapter of this dissertation, under the near-equilibrium assumption, with the help of linear response theory, fluctuation theorem and stochastic thermo- dynamics, we consider an inverse diffusion tensor in the parameter space of a heat engine. The inverse diffusion tensor of the stochastic oscillator induces a hyperbolic
space structure in the parameter space composed of the stiffness of the potential well and the inverse temperature of the heat bath. The inverse diffusion tensor of the resistor-capacitor circuit induces a Euclidean space structure in the parameter space composed of the capacitance of the capacitor and the inverse temperature of the heat bath. The average dissipation rate of a heat engine is given by a quadratic form (with a positive-definite inverse diffusion tensor) on the tangent space of the system parameter.
Along a finite-time protocol of a heat engine, besides the energy dissipation, there are two auxiliary quantities of interest: one is the extracted work of the heat engine and the other is the total heat supply from the bath to the engine. These two quantities are fundamental to the analysis of the efficiency of a heat engine. In Chapter 2, combining the energy dissipation and the extracted work of a heat engine, we introduce sub-Riemannian geometry structures underlying both heat engines.
In Chapter 3, after defining efficiency of a heat engine, we show the equivalence between an optimal control problem in the sub-Riemannian geometry of the heat engine and the problem of maximizing the efficiency of the heat engine. In this way, we bring geometric control theory to non-equilibrium statistical mechanics. In particular, we explicate the relation between conjugate point theory and the working loops of a heat engine. As a related calculation, we solve the isoperimetric problem in hyperbolic space as an optimal control problem in Chapter 4.
Based on the theoretical analysis in the first four chapters, in the final chap- ter of the dissertation, we adopt level set methods, mid-point approximation and shooting method to design maximum-efficiency working loops of both heat engines.
The associated efficiencies of these protocols are computed
Advancing Systems Biology in the International Conference on Intelligent Biology and Medicine (ICIBM) 2015
The 2015 International Conference on Intelligent Biology and Medicine (ICIBM 2015) was held on November 13-15, 2015 in Indianapolis, Indiana, USA. ICIBM 2015 included eight scientific sessions, three tutorial sessions, one poster session, and four keynote presentations that covered the frontier research in broad areas related to bioinformatics, systems biology, big data science, biomedical informatics, pharmacogenomics, and intelligent computing. Here, we present a summary of the 10 research articles that were selected from ICIBM 2015 and included in the supplement to BMC Systems Biology
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