220 research outputs found
Adaptive Electricity Scheduling in Microgrids
Microgrid (MG) is a promising component for future smart grid (SG)
deployment. The balance of supply and demand of electric energy is one of the
most important requirements of MG management. In this paper, we present a novel
framework for smart energy management based on the concept of
quality-of-service in electricity (QoSE). Specifically, the resident
electricity demand is classified into basic usage and quality usage. The basic
usage is always guaranteed by the MG, while the quality usage is controlled
based on the MG state. The microgrid control center (MGCC) aims to minimize the
MG operation cost and maintain the outage probability of quality usage, i.e.,
QoSE, below a target value, by scheduling electricity among renewable energy
resources, energy storage systems, and macrogrid. The problem is formulated as
a constrained stochastic programming problem. The Lyapunov optimization
technique is then applied to derive an adaptive electricity scheduling
algorithm by introducing the QoSE virtual queues and energy storage virtual
queues. The proposed algorithm is an online algorithm since it does not require
any statistics and future knowledge of the electricity supply, demand and price
processes. We derive several "hard" performance bounds for the proposed
algorithm, and evaluate its performance with trace-driven simulations. The
simulation results demonstrate the efficacy of the proposed electricity
scheduling algorithm.Comment: 12 pages, extended technical repor
Codebook Based Hybrid Precoding for Millimeter Wave Multiuser Systems
In millimeter wave (mmWave) systems, antenna architecture limitations make it
difficult to apply conventional fully digital precoding techniques but call for
low cost analog radio-frequency (RF) and digital baseband hybrid precoding
methods. This paper investigates joint RF-baseband hybrid precoding for the
downlink of multiuser multi-antenna mmWave systems with a limited number of RF
chains. Two performance measures, maximizing the spectral efficiency and the
energy efficiency of the system, are considered. We propose a codebook based RF
precoding design and obtain the channel state information via a beam sweep
procedure. Via the codebook based design, the original system is transformed
into a virtual multiuser downlink system with the RF chain constraint.
Consequently, we are able to simplify the complicated hybrid precoding
optimization problems to joint codeword selection and precoder design (JWSPD)
problems. Then, we propose efficient methods to address the JWSPD problems and
jointly optimize the RF and baseband precoders under the two performance
measures. Finally, extensive numerical results are provided to validate the
effectiveness of the proposed hybrid precoders.Comment: 35 pages, 9 figures, to appear in Trans. on Signal Process, 201
Enzyme catalytic resonance scattering spectral detection of trace hydrogen peroxide using guaiacol as substrate
Hydrogen peroxide oxidized guaiacol to form tetramer particles that exhibited a strong resonance scattering (RS) peak at 530 nm in the presence of horseradish peroxidase (HRP) in citric acid-Na2HPO4 buffer solution of pH 4.4. The RS peak increased when the concentration of hydrogen peroxide increased. The increased RS intensity (ΔI530 nm) was linear to the hydrogen peroxide concentration in the range of 0.55-27.6 μM, with a linear regression equation of ΔI530 nm = 17.1C + 1.6, a relative coefficient of 0.9996 and a detection limit of 0.03 μM H2O2. This proposed method was applied to detect hydrogen peroxide in rain water, with sensitivity, selectivity, rapidity, and recovery of 98.0-104 %.KEY WORDS: HRP, H2O2, Guaiacol, Resonance scattering spectral method Bull. Chem. Soc. Ethiop. 2011, 25(2), 161-168.Â
Forgedit: Text Guided Image Editing via Learning and Forgetting
Text guided image editing on real images given only the image and the target
text prompt as inputs, is a very general and challenging problem, which
requires the editing model to reason by itself which part of the image should
be edited, to preserve the characteristics of original image, and also to
perform complicated non-rigid editing. Previous fine-tuning based solutions are
time-consuming and vulnerable to overfitting, limiting their editing
capabilities. To tackle these issues, we design a novel text guided image
editing method, Forgedit. First, we propose a novel fine-tuning framework which
learns to reconstruct the given image in less than one minute by vision
language joint learning. Then we introduce vector subtraction and vector
projection to explore the proper text embedding for editing. We also find a
general property of UNet structures in Diffusion Models and inspired by such a
finding, we design forgetting strategies to diminish the fatal overfitting
issues and significantly boost the editing abilities of Diffusion Models. Our
method, Forgedit, implemented with Stable Diffusion, achieves new
state-of-the-art results on the challenging text guided image editing benchmark
TEdBench, surpassing the previous SOTA method Imagic with Imagen, in terms of
both CLIP score and LPIPS score. Codes are available at
https://github.com/witcherofresearch/Forgedit.Comment: Codes are available at https://github.com/witcherofresearch/Forgedi
An NLoS-based Enhanced Sensing Method for MmWave Communication System
The millimeter-wave (mmWave)-based Wi-Fi sensing technology has recently
attracted extensive attention since it provides a possibility to realize higher
sensing accuracy. However, current works mainly concentrate on sensing
scenarios where the line-of-sight (LoS) path exists, which significantly limits
their applications. To address the problem, we propose an enhanced mmWave
sensing algorithm in the 3D non-line-of-sight environment (mm3NLoS), aiming to
sense the direction and distance of the target when the LoS path is weak or
blocked. Specifically, we first adopt the directional beam to estimate the
azimuth/elevation angle of arrival (AoA) and angle of departure (AoD) of the
reflection path. Then, the distance of the related path is measured by the fine
timing measurement protocol. Finally, we transform the AoA and AoD of the
multiple non-line-of-sight (NLoS) paths into the direction vector and then
obtain the information of targets based on the geometric relationship. The
simulation results demonstrate that mm3NLoS can achieve a centimeter-level
error with a 2m spacing. Compared to the prior work, it can significantly
reduce the performance degradation under the NLoS condition
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