147 research outputs found
Commitment in First-Price Auctions
We study a variation of the single-item sealed-bid first-price auction where one bidder (the leader) is given the option to publicly pre-commit to a distribution from which her bid will be drawn
Priority Rules for Multi‐Task Due‐Date Scheduling under Varying Processing Costs
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135700/1/poms12606.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135700/2/poms12606_am.pd
A Multi-timescale and Chance-Constrained Energy Dispatching Strategy of Integrated Heat-Power Community with Shared Hybrid Energy Storage
The community in the future may develop into an integrated heat-power system,
which includes a high proportion of renewable energy, power generator units,
heat generator units, and shared hybrid energy storage. In the integrated
heat-power system with coupling heat-power generators and demands, the key
challenges lie in the interaction between heat and power, the inherent
uncertainty of renewable energy and consumers' demands, and the multi-timescale
scheduling of heat and power. In this paper, we propose a game theoretic model
of the integrated heat-power system. For the welfare-maximizing community
operator, its energy dispatch strategy is under chance constraints, where the
day-ahead scheduling determines the scheduled energy dispatching strategies,
and the real-time dispatch considers the adjustment of generators. For
utility-maximizing consumers, their demands are sensitive to the preference
parameters. Taking into account the uncertainty in both renewable energy and
consumer demand, we prove the existence and uniqueness of the Stackelberg game
equilibrium and develop a fixed point algorithm to find the market equilibrium
between the community operator and community consumers. Numerical simulations
on integrated heat-power system validate the effectiveness of the proposed
multi-timescale integrated heat and power model
Policy Design for Controlling Set-Point Temperature of ACs in Shared Spaces of Buildings
Air conditioning systems are responsible for the major percentage of energy
consumption in buildings. Shared spaces constitute considerable office space
area, in which most office employees perform their meetings and daily tasks,
and therefore the ACs in these areas have significant impact on the energy
usage of the entire office building. The cost of this energy consumption,
however, is not paid by the shared space users, and the AC's temperature
set-point is not determined based on the users' preferences. This latter factor
is compounded by the fact that different people may have different choices of
temperature set-points and sensitivities to change of temperature. Therefore,
it is a challenging task to design an office policy to decide on a particular
set-point based on such a diverse preference set. As a result, users are not
aware of the energy consumption in shared spaces, which may potentially
increase the energy wastage and related cost of office buildings. In this
context, this paper proposes an energy policy for an office shared space by
exploiting an established temperature control mechanism. In particular, we
choose meeting rooms in an office building as the test case and design a policy
according to which each user of the room can give a preference on the
temperature set-point and is paid for felt discomfort if the set-point is not
fixed according to the given preference. On the other hand, users who enjoy the
thermal comfort compensate the other users of the room. Thus, the policy
enables the users to be cognizant and responsible for the payment on the energy
consumption of the office space they are sharing, and at the same time ensures
that the users are satisfied either via thermal comfort or through incentives.
The policy is also shown to be beneficial for building management. Through
experiment based case studies, we show the effectiveness of the proposed
policy.Comment: Journal paper accepted in Energy & Buildings (Elsevier
Cooperation of storage operation in a power network with renewable generation
In this paper, we seek to properly schedule the operation of multiple storage devices so as to minimize the expected total cost (of conventional generation) in a power network with intermittent renewable generation. Since the power network constraints make it intractable to compute optimal storage operation policies through dynamic programming-based approaches, we propose a Lyapunov optimization-based online algorithm (LOPN), which makes decisions based only on the current state of the system (i.e., the current demand and renewable generation). The proposed algorithm is computationally simple and achieves asymptotic optimality (as the capacity of energy storage grows large). To improve the performance of the LOPN algorithm for the case with limited storage capacity, we propose a threshold-based energy storage management (TESM) algorithm that utilizes the forecast information (on demand and renewable generation) over the next a few time slots to make storage operation decisions. Numerical experiments are conducted on IEEE 6- and 9-bus test systems to validate the asymptotic optimality of LOPN, and compare the performance of LOPN and TESM. Numerical results show that TESM significantly outperforms LOPN when the storage capacity is relatively small
The Maize NBS-LRR Gene ZmNBS25 Enhances Disease Resistance in Rice and Arabidopsis
Nucleotide-binding site-leucine-rich repeat (NBS-LRR) domain proteins are immune sensors and play critical roles in plant disease resistance. In this study, we cloned and characterized a novel NBS-LRR gene ZmNBS25 in maize. We found that ZmNBS25 could response to pathogen inoculation and salicylic acid (SA) treatment in maize, and transient overexpression of ZmNBS25 induced a hypersensitive response in tobacco. High-performance liquid chromatography (HPLC) analysis showed that, compared to control plants, ZmNBS25 overexpression (ZmNBS25-OE) in Arabidopsis and rice resulted in higher SA levels. By triggering the expression of certain defense-responsive genes, ZmNBS25-OE enhanced the resistance of Arabidopsis and rice to Pseudomonas syringae pv. tomato DC3000 and sheath blight disease, respectively. Moreover, we found little change of grain size and 1000-grain weight between ZmNBS25-OE rice lines and controls. Together, our results suggest that ZmNBS25 can function as a disease resistance gene across different species, being a valuable candidate for engineering resistance in breeding programs
Iterative Energy-Efficient Stable Matching Approach for Context-Aware Resource Allocation in D2D Communications
Energy efficiency (EE) is critical to fully achieve the huge potentials of device-to-device (D2D) communications with limited battery capacity. In this paper, we consider the two-stage EE optimization problem, which consists of a joint spectrum and power allocation problem in the first stage, and a context-aware D2D peer selection problem in the second stage. We provide a general tractable framework for solving the combinatorial problem, which is NP-hard due to the binary and continuous optimization variables. In each stage, user equipments (UEs) from two finite and disjoint sets are matched in a two-sided stable way based on the mutual preferences. First, the preferences of UEs are defined as the maximum achievable EE. An iterative power allocation algorithm is proposed to optimize EE under a specific match, which is developed by exploiting nonlinear fractional programming and Lagrange dual decomposition. Second, we propose an iterative matching algorithm, which first produces a stable match based on the fixed preferences, and then dynamically updates the preferences according to the latest matching results in each iteration. Finally, the properties of the proposed algorithm, including stability, optimality, complexity, and scalability, are analyzed in detail. Numerical results validate the efficiency and superiority of the proposed algorithm under various simulation scenarios
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