5,075 research outputs found
A two level feedback system design to provide regulation reserve
Demand side management has gained increasing importance as the penetration of renewable energy grows. Based on a Markov jump process modelling of a group of thermostatic loads, this paper proposes a two level feedback system design be- tween the independent system operator (ISO) and the regulation service provider such that two objectives are achieved: (1) the ISO can optimally dispatch regulation signals to multiple providers in real time in order to reduce the requirement for expensive spinning reserves, and (2) each regulation provider can control its thermostatic loads to respond the ISO signal. It is also shown that the amount of regulation service that can be provided is implicitly restricted by a few fundamental parameters of the provider itself, such as the allowable set point choice and its thermal constant. An interesting finding is that the regulation provider’s ability to provide a large amount of long term accumulated regulation and short term signal tracking restrict each other. Simulation results are presented to verify and illustrate the performance of the proposed framework
A Packetized Direct Load Control Mechanism for Demand Side Management
Electricity peaks can be harmful to grid stability and result in additional
generation costs to balance supply with demand. By developing a network of
smart appliances together with a quasi-decentralized control protocol, direct
load control (DLC) provides an opportunity to reduce peak consumption by
directly controlling the on/off switch of the networked appliances. This paper
proposes a packetized DLC (PDLC) solution that is illustrated by an application
to air conditioning temperature control. Here the term packetized refers to a
fixed time energy usage authorization. The consumers in each room choose their
preferred set point, and then an operator of the local appliance pool will
determine the comfort band around the set point. We use a thermal dynamic model
to investigate the duty cycle of thermostatic appliances. Three theorems are
proposed in this paper. The first two theorems evaluate the performance of the
PDLC in both transient and steady state operation. The first theorem proves
that the average room temperature would converge to the average room set point
with fixed number of packets applied in each discrete interval. The second
theorem proves that the PDLC solution guarantees to control the temperature of
all the rooms within their individual comfort bands. The third theorem proposes
an allocation method to link the results in theorem 1 and assumptions in
theorem 2 such that the overall PDLC solution works. The direct result of the
theorems is that we can reduce the consumption oscillation that occurs when no
control is applied. Simulation is provided to verify theoretical results.Comment: the 51st IEEE Conference on Decision and Control,December 10-13,
Maui, 201
Quantum ground state isoperimetric inequalities for the energy spectrum of local Hamiltonians
We investigate the relationship between the energy spectrum of a local
Hamiltonian and the geometric properties of its ground state. By generalizing a
standard framework from the analysis of Markov chains to arbitrary
(non-stoquastic) Hamiltonians we are naturally led to see that the spectral gap
can always be upper bounded by an isoperimetric ratio that depends only on the
ground state probability distribution and the range of the terms in the
Hamiltonian, but not on any other details of the interaction couplings. This
means that for a given probability distribution the inequality constrains the
spectral gap of any local Hamiltonian with this distribution as its ground
state probability distribution in some basis (Eldar and Harrow derived a
similar result in order to characterize the output of low-depth quantum
circuits). Going further, we relate the Hilbert space localization properties
of the ground state to higher energy eigenvalues by showing that the presence
of k strongly localized ground state modes (i.e. clusters of probability, or
subsets with small expansion) in Hilbert space implies the presence of k energy
eigenvalues that are close to the ground state energy. Our results suggest that
quantum adiabatic optimization using local Hamiltonians will inevitably
encounter small spectral gaps when attempting to prepare ground states
corresponding to multi-modal probability distributions with strongly localized
modes, and this problem cannot necessarily be alleviated with the inclusion of
non-stoquastic couplings
Rising Unemployment, Medicaid and the Uninsured
Estimates the impact of different levels of unemployment on healthcare coverage and state costs for Medicaid and State Children's Health Insurance Programs (SCHIP) and the uninsured. Considers the impact of proportional budget cuts on Medicaid and SCHIP
Control and Communication Protocols that Enable Smart Building Microgrids
Recent communication, computation, and technology advances coupled with
climate change concerns have transformed the near future prospects of
electricity transmission, and, more notably, distribution systems and
microgrids. Distributed resources (wind and solar generation, combined heat and
power) and flexible loads (storage, computing, EV, HVAC) make it imperative to
increase investment and improve operational efficiency. Commercial and
residential buildings, being the largest energy consumption group among
flexible loads in microgrids, have the largest potential and flexibility to
provide demand side management. Recent advances in networked systems and the
anticipated breakthroughs of the Internet of Things will enable significant
advances in demand response capabilities of intelligent load network of
power-consuming devices such as HVAC components, water heaters, and buildings.
In this paper, a new operating framework, called packetized direct load control
(PDLC), is proposed based on the notion of quantization of energy demand. This
control protocol is built on top of two communication protocols that carry
either complete or binary information regarding the operation status of the
appliances. We discuss the optimal demand side operation for both protocols and
analytically derive the performance differences between the protocols. We
propose an optimal reservation strategy for traditional and renewable energy
for the PDLC in both day-ahead and real time markets. In the end we discuss the
fundamental trade-off between achieving controllability and endowing
flexibility
How Will the Affordable Care Act Affect Jobs?
Examines the argument that the 2010 healthcare reform law will destroy jobs, including claims about the increase in federal spending and likely effect on business. Considers impact relative to the economy's size, offsets, and cost-containment effects
Why the Individual Mandate Matters
Compares estimates of coverage rates for the nonelderly and of spending by government, employers, individuals, and the overall health system under the 2010 healthcare reform law and estimates under a scenario in which the individual mandate is eliminated
The Effects of Large Premium Increases on Individuals, Families, and Small Businesses
Estimates the impact of rising insurance premiums on coverage, costs, adverse selection, public spending, and small employers' offers of insurance under three scenarios. Compares projections for loss of coverage by age, income, and type of insurance
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