104 research outputs found
Sequential Logistic Principal Component Analysis (SLPCA): Dimensional Reduction in Streaming Multivariate Binary-State System
Sequential or online dimensional reduction is of interests due to the
explosion of streaming data based applications and the requirement of adaptive
statistical modeling, in many emerging fields, such as the modeling of energy
end-use profile. Principal Component Analysis (PCA), is the classical way of
dimensional reduction. However, traditional Singular Value Decomposition (SVD)
based PCA fails to model data which largely deviates from Gaussian
distribution. The Bregman Divergence was recently introduced to achieve a
generalized PCA framework. If the random variable under dimensional reduction
follows Bernoulli distribution, which occurs in many emerging fields, the
generalized PCA is called Logistic PCA (LPCA). In this paper, we extend the
batch LPCA to a sequential version (i.e. SLPCA), based on the sequential convex
optimization theory. The convergence property of this algorithm is discussed
compared to the batch version of LPCA (i.e. BLPCA), as well as its performance
in reducing the dimension for multivariate binary-state systems. Its
application in building energy end-use profile modeling is also investigated.Comment: 6 pages, 4 figures, conference submissio
Social Game for Building Energy Efficiency: Utility Learning, Simulation, and Analysis
We describe a social game that we designed for encouraging energy efficient
behavior amongst building occupants with the aim of reducing overall energy
consumption in the building. Occupants vote for their desired lighting level
and win points which are used in a lottery based on how far their vote is from
the maximum setting. We assume that the occupants are utility maximizers and
that their utility functions capture the tradeoff between winning points and
their comfort level. We model the occupants as non-cooperative agents in a
continuous game and we characterize their play using the Nash equilibrium
concept. Using occupant voting data, we parameterize their utility functions
and use a convex optimization problem to estimate the parameters. We simulate
the game defined by the estimated utility functions and show that the estimated
model for occupant behavior is a good predictor of their actual behavior. In
addition, we show that due to the social game, there is a significant reduction
in energy consumption
Environmental Sensing by Wearable Device for Indoor Activity and Location Estimation
We present results from a set of experiments in this pilot study to
investigate the causal influence of user activity on various environmental
parameters monitored by occupant carried multi-purpose sensors. Hypotheses with
respect to each type of measurements are verified, including temperature,
humidity, and light level collected during eight typical activities: sitting in
lab / cubicle, indoor walking / running, resting after physical activity,
climbing stairs, taking elevators, and outdoor walking. Our main contribution
is the development of features for activity and location recognition based on
environmental measurements, which exploit location- and activity-specific
characteristics and capture the trends resulted from the underlying
physiological process. The features are statistically shown to have good
separability and are also information-rich. Fusing environmental sensing
together with acceleration is shown to achieve classification accuracy as high
as 99.13%. For building applications, this study motivates a sensor fusion
paradigm for learning individualized activity, location, and environmental
preferences for energy management and user comfort.Comment: submitted to the 40th Annual Conference of the IEEE Industrial
Electronics Society (IECON
Distributed Control of Multi-zone HVAC Systems Considering Indoor Air Quality
This paper studies a scalable control method for multi-zone heating,
ventilation and air-conditioning (HVAC) systems to optimize the energy cost for
maintaining thermal comfort and indoor air quality (IAQ) (represented by CO2)
simultaneously. This problem is computationally challenging due to the complex
system dynamics, various spatial and temporal couplings as well as multiple
control variables to be coordinated. To address the challenges, we propose a
two-level distributed method (TLDM) with a upper level and lower level control
integrated. The upper level computes zone mass flow rates for maintaining zone
thermal comfort with minimal energy cost, and then the lower level
strategically regulates zone mass flow rates and the ventilation rate to
achieve IAQ while preserving the near energy saving performance of upper level.
As both the upper and lower level computation are deployed in a distributed
manner, the proposed method is scalable and computationally efficient. The
near-optimal performance of the method in energy cost saving is demonstrated
through comparison with the centralized method. In addition, the comparisons
with the existing distributed method show that our method can provide IAQ with
only little increase of energy cost while the latter fails. Moreover, we
demonstrate our method outperforms the demand controlled ventilation strategies
(DCVs) for IAQ management with about 8-10% energy cost reduction.Comment: 12 pages, 12 figure
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