Stability analysis of event-triggered anytime control with multiple control laws

To deal with time-varying processor availability and lossy communication channels in embedded and networked control systems, one can employ an event-triggered sequence-based anytime control (E-SAC) algorithm. The main idea of E-SAC is, when computing resources and measurements are available, to compute a sequence of tentative control inputs and store them in a buffer for potential future use. State-dependent Random-time Drift (SRD) approach is often used to analyse and establish stability properties of such E-SAC algorithms. However, using SRD, the analysis quickly becomes combinatoric and hence difficult to extend to more sophisticated E-SAC. In this technical note, we develop a general model and a new stability analysis for E-SAC based on Markov jump systems. Using the new stability analysis, stochastic stability conditions of existing E-SAC are also recovered. In addition, the proposed technique systematically extends to a more sophisticated E-SAC scheme for which, until now, no analytical expression had been obtained.Comment: Accepted for publication in IEEE Transactions on Automatic Contro

Embedded ADMM-based QP solver for MPC with polytopic constraints

We propose an algorithm for solving quadratic programming (QP) problems with inequality and equality constraints arising from linear MPC. The proposed algorithm is based on the ‘alternating direction method of multipliers’ (ADMM), with the introduction of slack variables. In comparison with algorithms available in the literature, our proposed algorithm can handle the so-called sparse MPC formulation with general inequality constraints. Moreover, our proposed algorithm is suitable for implementation on embedded platforms where computational resources are limited. In some cases, our algorithm is division-free when certain fixed matrices are computed offline. This enables our algorithm to be implemented in fixed-point arithmetic on a FPGA. In this paper, we also propose heuristic rules to select the step size of ADMM for a good convergence rate.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/ECC.2015.733106

Banded Null Basis and ADMM for Embedded MPC

© 2017 In this paper, we propose an improved QP solver for embedded implementations of MPC controllers. We adopt a “reduced Hessian” approach for handling the equality constraints that arise in the well-known “banded” formulation of MPC (in which the predicted states are not eliminated). Our key observation is that a banded basis exists for the null space of the banded equality-constraint matrix, and that this leads to a QP of the same size as the “condensed” formulation of MPC problems, which is considerably smaller than the “banded” formulation. We use the Alternating Direction Method of Multipliers (ADMM) - which is known to be particularly suitable for embedded implementations - to solve this smaller QP problem. Our C implementation results for a particular MPC example (a 9-state, 3-input quadrotor) show that our proposed algorithm is about 4 times faster than an existing well-performing ADMM variant (“indirect indicator” ADMM or “iiADMM”) and 3 times faster than the well-known QP solver CVXGEN. The convergence rate and code size of the proposed ADMM variant is also comparable with iiADMM.National Research Foundation, Singapore

Circadian Clock Gene Regulation in Aging and Drug Discovery

The circadian clock is an endogenous timer in prokaryotes and mammals. Resting and adjusting the internal clock can assist in pacing the daily routine. Growing evidence indicates that the circadian clock and aging process are closely associated. The disruption of the circadian clock leads to accelerated aging and increased incidence of various diseases. In particular, elderly people are more vulnerable and have a higher risk of diseases than do young people. In this study, we reviewed studies on aging and circadian rhythms over the last decade, with a focus on circadian clock gene regulation in aging and drug discovery for targeting the circadian clock in diseases

CFD Simulation of Temperature Field Distribution of the Liquefied Hydrocarbon Spherical Tank Leaking

AbstractLiquefied hydrocarbon is normally stored under high pressure in overheating state in the spherical tank. Once leakage occurs, the liquefied hydrocarbon will quickly gasify and absorb a great deal of heat, making temperature of spherical tank decrease sharply. In order to investigate this process, physical model was established, and the Reynolds time averaged Navier-Stokes equation and k-ɛ turbulent model as the CFD simulation method were used in this study. The temperature distribution of the spherical tank and the environment after spherical tank pipeline leaking was analyzed. The influences of leakage location and leak area on the spherical tank temperature distribution were analyzed, and a meaningful conclusion was obtained. This study could provide theoretical basis and technical support for the safety control of liquefied hydrocarbon spherical tank leakage. © 2012 Published by Elsevier Ltd. Selection and/or peer-review (pre-review) under responsibility of the Capital University of Economics and Business, China Academy of Safety Science and Technology

The Connotation of Kidney Stores Essence Theory and Kidney Endocrine Substance

Traditional Chinese medicine (TCM) is a traditional healing system with unique theoretical system. The Zang‐Fu theory is the closest mapping to body\u27s physiological and pathological changes. Kidney is the most vital Zang organ in TCM system. However, the material basis of kidney essence is still undefined. In this chapter, we propose the idea that kidney endocrine substances, such as renin, kallikrein, erythropoietin (EPO), calcitriol, bone morphogenetic protein (BMP)‐7, and klotho, are potential candidates of the material basis of kidney essence. In addition, kidney‐nourishing therapy and related Chinese medicinal herbs are also introduced

PRNet:Pyramid Restoration Network for RAW Image Super-Resolution

Typically, image super-resolution (SR) methods are applied to the standard RGB (sRGB) images produced by the image signal processing (ISP) pipeline of digital cameras. However, due to error accumulation, low bit depth and the nonlinearity with scene radiance in sRGB images, performing SR on them is sub-optimal. To address this issue, a RAW image SR method called pyramid restoration network (PRNet) is proposed in this paper. Firstly, PRNet takes the low-resolution (LR) RAW image as input, and generates a rough estimation of the SR result in the linear color space. Afterwards, a pyramid refinement (PR) sub-network refines image details in the intermediate SR result and corrects its colors in a divide-and-conquer manner. To learn the appropriate colors for displaying, external guidance is extracted from the LR reference image in the sRGB color space, and then fed to the PR sub-network. To effectively incorporate the external guidance, the cross-layer correction module (CLCM), which fully investigates the long-range interactions between two input features, is introduced in the PR sub-network. Moreover, as different frequency components decomposed from the same image are highly correlated, in the PR sub-network, the refined features from a lower layer are utilized to support the feature refinement in an upper layer. Extensive experiments presented in this paper demonstrate that the proposed method is capable of recovering fine details and small structures in images while producing vivid colors that align with the output of a specific camera ISP pipeline

Isolation of salinity tolerant genes from the mangrove plant, Bruguiera cylindrica by using suppression subtractive hybridization (SSH) and bacterial functional screening

In this study, we have identified and isolated 126 salinity tolerant cDNAs from the root of a mangrove plant, Bruguiera cylindrica (L.) Blume by using suppression subtractive hybridization (SSH) and bacterial functional screening. Sequencing of 51 subtracted cDNA clones that were differentially expressed in the root of B. cylindrica exposed to 20 parts per thousand (ppt) NaCl water revealed 10 tentative unique genes (TUGs) with putative functions in protein synthesis, storage and destination, metabolism, intracellular trafficking and other functions; and 9 unknown proteins. Meanwhile, the 75 cDNA sequences of B. cylindrica that conferred salinity tolerance to Escherichia coli consisted of 29 TUGs with putative functions in transportation, metabolism and other functions; and 33 with unknown functions. Both approaches yielded 42 unique sequencess that have not been reported else where to be stress related and might provide further understanding of adaptations of this plant to salinity stress

catena-Poly[[[diaqua­bis(2-methyl-6-oxo-1,6-dihydro-3,4′-bipyridine-5-carbo­nitrile)copper(II)]-μ-sulfato] tetra­hydrate]

In the title polymer, {[Cu(SO4)(C12H9N3O)2(H2O)2]·4H2O}n, both the metal center and the sulfate anion are located on a twofold axis. The CuII ion is coordinated by two pyridyl N atoms from two symmetry-related organic ligands, two O atoms from two symmetry-related water mol­ecules, and two O atoms from two symmetry-related sulfate anions, resulting in a distorted octa­hedral geometry. The sulfate anions act as μ2-bridges and connect metal ions, forming a one-dimensional chain along the b axis. The three-dimensional crystal structure is established through inter­molecular N—H⋯O and O—H⋯O hydrogen bonds involving the organic ligands, sulfate anions, coordinated and uncoordinated water mol­ecules, and through π–π inter­acting 2-pyridone rings, with centroid–centroid separations of ca 3.96 Å and tilt angles of ca 2.62°