A Hierarchical Framework of Cloud Resource Allocation and Power Management Using Deep Reinforcement Learning

Automatic decision-making approaches, such as reinforcement learning (RL), have been applied to (partially) solve the resource allocation problem adaptively in the cloud computing system. However, a complete cloud resource allocation framework exhibits high dimensions in state and action spaces, which prohibit the usefulness of traditional RL techniques. In addition, high power consumption has become one of the critical concerns in design and control of cloud computing systems, which degrades system reliability and increases cooling cost. An effective dynamic power management (DPM) policy should minimize power consumption while maintaining performance degradation within an acceptable level. Thus, a joint virtual machine (VM) resource allocation and power management framework is critical to the overall cloud computing system. Moreover, novel solution framework is necessary to address the even higher dimensions in state and action spaces. In this paper, we propose a novel hierarchical framework for solving the overall resource allocation and power management problem in cloud computing systems. The proposed hierarchical framework comprises a global tier for VM resource allocation to the servers and a local tier for distributed power management of local servers. The emerging deep reinforcement learning (DRL) technique, which can deal with complicated control problems with large state space, is adopted to solve the global tier problem. Furthermore, an autoencoder and a novel weight sharing structure are adopted to handle the high-dimensional state space and accelerate the convergence speed. On the other hand, the local tier of distributed server power managements comprises an LSTM based workload predictor and a model-free RL based power manager, operating in a distributed manner.Comment: accepted by 37th IEEE International Conference on Distributed Computing (ICDCS 2017

Empirical metallicity-dependent calibrations of effective temperature against colours for dwarfs and giants based on interferometric data

We present empirical metallicity-dependent calibrations of effective temperature against colours for dwarfs of luminosity classes IV and V and for giants of luminosity classes II and III, based on a collection from the literature of about two hundred nearby stars with direct effective temperature measurements of better than 2.5 per cent. The calibrations are valid for an effective temperature range 3,100 - 10,000 K for dwarfs of spectral types M5 to A0 and 3,100 - 5,700 K for giants of spectral types K5 to G5. A total of twenty-one colours for dwarfs and eighteen colours for giants of bands of four photometric systems, i.e. the Johnson ($UBVR_{\rm J}I_{\rm J}JHK$), the Cousins ($R_{\rm C}I_{\rm C}$), the Sloan Digital Sky Survey (SDSS, $gr$) and the Two Micron All Sky Survey (2MASS, $JHK_{\rm s}$), have been calibrated. Restricted by the metallicity range of the current sample, the calibrations are mainly applicable for disk stars ([Fe/H]$\,\gtrsim\,-1.0$). The normalized percentage residuals of the calibrations are typically 2.0 and 1.5 per cent for dwarfs and giants, respectively. Some systematic discrepancies at various levels are found between the current scales and those available in the literature (e.g. those based on the infrared flux method IRFM or spectroscopy). Based on the current calibrations, we have re-determined the colours of the Sun. We have also investigated the systematic errors in effective temperatures yielded by the current on-going large scale low- to intermediate-resolution stellar spectroscopic surveys. We show that the calibration of colour ($g-K_{\rm s}$) presented in the current work provides an invaluable tool for the estimation of stellar effective temperature for those on-going or upcoming surveys.Comment: 28 pages, 19 figures, 8 tables, accepted for publication in MNRA

Apoptosis-inducing effect of 6,7-dimethoxy-4'-hydroxy-8- formylflavon from Nicotiana tabacum L leaf in human hepatoma HepG2 cells via activation of mitochondriamediated apoptotic pathway

Purpose: To study the anti-proliferative and apoptotic influences of 6,7-dimethoxy-4'-hydroxy-8- formylflavon (DHF) from the leaves of Nicotiana tabacum L. in human hepatoma HepG2 cells, and the underlying mechanisms.Methods: The anti-proliferative effect of DHF (10 - 50 μg/mL) on HepG2 cells was assessed by CCK-8 assay. The pro-apoptotic effect of DHF (10, 20 and 30 μg/mL) on HepG2 cells was investigated via flow cytometry, while the mechanisms involved were studied using western blot. Xenograft assay was employed for determination of the in vivo effect of DHF (40 mg/kg/day) on HepG2 cell-induced tumor.Results: The proliferation of HepG2 cells was inhibited by DHF (IC50 = 25.87 μg/mL) due to apoptosis. In addition, xenograft assay revealed that HepG2 cell-induced tumor growth was significantly suppressed by DHF (p < 0.05 or 0.01) without any effects on mice body weights. The expressions of Survivin and Bcl-2 proteins were significantly decreased, while those of Bax, c-caspase-9, and ccaspase- 3 proteins were significantly increased by DHF (p < 0.05 or 0.01), leading to increase in cytoplasmic levels of Smac and cytochrome c proteins.Conclusion: The underlying mechanism DHF-mediated apoptotic changes in HepG2 cells in vitro and in vivo involves induction of the mitochondrial pathway of apoptosis. Thus, DHF is a good drug candidate for the development of an effective therapy for liver cancer.Keywords: 6,7-Dimethoxy-4'-hydroxy-8-formylflavon, HepG2 cells, Hepatoma, Mitochondria, Apoptosis, Bax, Cytochrome C, Survivi

Spiniform phase-encoded metagratings entangling arbitrary rational-order orbital angular momentum

Quantum entanglements between integer-order and fractional-order orbital angular momentums (OAMs) have been previously discussed. However, the entangled nature of arbitrary rational-order OAM has long been considered a myth due to the absence of an effective strategy for generating arbitrary rational-order OAM beams. Therefore, we report a single metadevice comprising a bilaterally symmetric grating with an aperture, creating optical beams with dynamically controllable OAM values that are continuously varying over a rational range. Due to its encoded spiniform phase, this novel metagrating enables the production of an average OAM that can be increased without a theoretical limit by embracing distributed singularities, which differs significantly from the classic method of stacking phase singularities using fork gratings. This new method makes it possible to probe the unexplored niche of quantum entanglement between arbitrarily defined OAMs in light, which could lead to the complex manipulation of microparticles, high-dimensional quantum entanglement and optical communication. We show that quantum coincidence based on rational-order OAM-superposition states could give rise to low cross-talks between two different states that have no significant overlap in their spiral spectra. Additionally, future applications in quantum communication and optical micromanipulation may be found

catena-Poly[[(2,2′-bipyridine-κ2 N,N′)copper(I)]-μ-cyanido-κ2 C:N-[(2,2′-bipyridine-κ2 N,N′)copper(I)]-μ-thio­cyanato-κ2 S:N]

The title compound, [Cu2(CN)(SCN)(C10H8N2)2]n, contains two crystallographically independent CuI atoms, each in a distorted tetra­hedral geometry. Each Cu atom is coordinated by a bidentate chelating 2,2′-bipyridine ligand. A bridging cyanide anion links the two Cu(2,2′-bipyridine) units to form a binuclear unit. Adjacent binuclear units are connected by a thio­cyanate anion into a one-dimensional helical chain along [010]. The cyanide anion is disordered, with each site occupied by both C and N atoms in an occupancy ratio of 0.61 (5):0.39 (5). The S atom of the thio­cyanate anion is also disordered over two sites, with occupancy factors of 0.61 (3) and 0.39 (3). There are π–π inter­actions between the pyridyl rings of neighbouring chains [centroid–centroid distance = 3.82 (1) Å]

Three odorant-binding proteins are involved in the behavioral response of Sogatella furcifera to rice plant volatiles

Plant volatiles play an important role in regulating insect behavior. Odorant binding proteins (OBPs) are involved in the first step of the olfactory signal transduction pathway and plant volatiles recognition. Sogatella furcifera is one of the most destructive pests of rice crops. Understanding the functions of S. furcifera OBPs (SfurOBPs) in the host plant location and the behavioral responses of S. furcifera to rice plant volatiles could lead to improved, more environmentally-friendly, methods for controlling this pest. We found that SfurOBP1 displayed only weak binding with all the tested volatiles. SfurOBP2, SfurOBP3 and SfurOBP11 had different binding affinities to β-ionone. SfurOBP2 and SfurOBP11 had strong binding affinities to β-caryophyllene (Ki = 2.23 µM) and plant alcohol (Ki = 2.98 µM), respectively. The results of Y-olfactometer experiments indicate that S. furcifera was significantly repelled by octanal and n-octane but strongly attracted by (+)-limonene, acetophenone, 2-heptanone, n-hendecane, α-farnesene and β-ionone. Furthermore, the dsRNA-mediated gene silencing of SfurOBP2, SfurOBP3 and SfurOBP11 shifted the olfactory behavior of S. furcifera for β-ionone, α-farnesene and plant alcohol, respectively. These results suggest that the SfurOBPs are involved in the recognition of rice plant volatiles, and several potential repellants and lures for controlling this pest

On the Secrecy Performance of Random VLC Networks with Imperfect CSI and Protected Zone

This paper investigates the physical-layer security for a random indoor visible light communication (VLC) network with imperfect channel state information (CSI) and a protected zone. The VLC network consists of three nodes, i.e., a transmitter (Alice), a legitimate receiver (Bob), and an eavesdropper (Eve). Alice is fixed in the center of the ceiling, and the emitted signal at Alice satisfies the non-negativity and the dimmable average optical intensity constraint. Bob and Eve are randomly deployed on the receiver plane. By employing the protected zone and considering the imperfect CSI, the stochastic characteristics of the channel gains for both the main and the eavesdropping channels is first analyzed. After that, the closed-form expressions of the average secrecy capacity and the lower bound of secrecy outage probability are derived, respectively. Finally, Monte-Carlo simulations are provided to verify the accuracy of the derived theoretical expressions. Moreover, the impacts of the nominal optical intensity, the dimming target, the protected zone and the imperfect CSI on secrecy performance are discussed, respectively.Comment: Accepted by IEEE Systems Joutna