379 research outputs found
Design of intelligent power consumption optimization and visualization management platform for large buildings based on internet of things
The buildings provide a significant contribution to total energy consumption and CO2 emission. It has been estimated that the development of an intelligent power consumption monitor and control system will result in about 30% savings in energy consumption. This design innovatively integrates the advanced technologies such as the internet of things, the internet, intelligent buildings and intelligent electricity which can offer open, efficient, convenient energy consumption detection platform in demand side and visual management demonstration application platform in power enterprises side. The system was created to maximize the effective and efficient the use of energy resource. It was development around sensor networks and intelligent gateway and the monitoring center software. This will realize the highly integration and comprehensive application in energy and information to meet the needs with intelligent building
Performance analysis of a polling model with BMAP and across-queue state-dependent service discipline
As various video services become popular, video streaming will dominate the mobile data traffic. The H.264 standard has been widely used for video compression. As the successor to H.264, H.265 can compress video streaming better, hence it is gradually gaining market share. However, in the short term H.264 will not be completely replaced, and will co-exist with H.265. Using H.264 and H.265 standards, three types of frames are generated, and among different types of frames exist dependencies. Since the radio resources are limited, using dependencies and quantities of frames in buffers, an appropriate time division transmission policy can be applied to transmit different types of frames sequentially, in order to avoid the occurrence of video carton or decoding failure. Polling models with batch Markovian arrival process (BMAP) and across-queue state-dependent service discipline are considered to be effective means in the design and optimization of appropriate time division transmission policies. However, the BMAP and across-queue state-dependent service discipline of the polling models lead to the large state space and several coupled state transition processes, which complicate the performance analysis. There have been very few researches in this regard. In this paper, a polling model of this type is analyzed. By constructing a supplementary embedded Markov chain and applying the matrix-analytic method based on the semi-regenerative process, the expressions of important performance measures including the joint queue length distribution, the customer blocking probability and the customer mean waiting time are obtained. The analysis will provide inspiration for analyzing the polling models with BMAP and across-queue state-dependent service discipline, to guide the design and optimization of time division transmission policies for transmitting the video compressed by H.264 and H.265
Bayesian Parameter Inference for Partially Observed Diffusions using Multilevel Stochastic Runge-Kutta Methods
We consider the problem of Bayesian estimation of static parameters
associated to a partially and discretely observed diffusion process. We assume
that the exact transition dynamics of the diffusion process are unavailable,
even up-to an unbiased estimator and that one must time-discretize the
diffusion process. In such scenarios it has been shown how one can introduce
the multilevel Monte Carlo method to reduce the cost to compute posterior
expected values of the parameters for a pre-specified mean square error (MSE).
These afore-mentioned methods rely on upon the Euler-Maruyama discretization
scheme which is well-known in numerical analysis to have slow convergence
properties. We adapt stochastic Runge-Kutta (SRK) methods for Bayesian
parameter estimation of static parameters for diffusions. This can be
implemented in high-dimensions of the diffusion and seemingly under-appreciated
in the uncertainty quantification and statistics fields. For a class of
diffusions and SRK methods, we consider the estimation of the posterior
expectation of the parameters. We prove that to achieve a MSE of
, for given, the associated work is
. Whilst the latter is achievable for the Milstein
scheme, this method is often not applicable for diffusions in dimension larger
than two. We also illustrate our methodology in several numerical examples
On the use of an explicit chemical mechanism to dissect peroxy acetyl nitrate formation.
Peroxy acetyl nitrate (PAN) is a key component of photochemical smog and plays an important role in atmospheric chemistry. Though it has been known that PAN is produced via reactions of nitrogen oxides (NOx) with some volatile organic compounds (VOCs), it is difficult to quantify the contributions of individual precursor species. Here we use an explicit photochemical model--Master Chemical Mechanism (MCM) model--to dissect PAN formation and identify principal precursors, by analyzing measurements made in Beijing in summer 2008. PAN production was sensitive to both NOx and VOCs. Isoprene was the predominant VOC precursor at suburb with biogenic impact, whilst anthropogenic hydrocarbons dominated at downtown. PAN production was attributable to a relatively small class of compounds including NOx, xylenes, trimethylbenzenes, trans/cis-2-butenes, toluene, and propene. MCM can advance understanding of PAN photochemistry to a species level, and provide more relevant recommendations for mitigating photochemical pollution in large cities
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