Energy
A Cognitively Inspired Approach for Knowledge Representation and Reasoning in Knowledge-Based Systems
Carbonera, Joel Luis (UFRGS) | Abel, Mara (UFRGS)
The classical theory assumes that each concept is represented by a set of features In this thesis, I investigate a hybrid knowledge representation that are shared by all the instances that are abstracted by approach that combines classic knowledge the concept. In this way, concepts can be viewed as rules representations, such as rules and ontologies, for classifying objects based on features. The prototype theory, with other cognitively plausible representations, on the other hand, states that concepts are represented such as prototypes and exemplars. The resulting through a typical instance, which has the typical features of framework can combine the strengths of the instances of the concept. Finally, the exemplar theory assumes each approach of knowledge representation, avoiding that each concept is represented by a set of exemplars their weaknesses. It can be used for developing of it. These exemplars are real entities that were previously knowledge-based systems that combine logicbased experienced by the agent. In theories based on prototypes or reasoning and similarity-based reasoning in exemplars, the categorization of a given entity is performed problem-solving processes.
Probabilistic Backpropagation for Scalable Learning of Bayesian Neural Networks
Hernรกndez-Lobato, Josรฉ Miguel, Adams, Ryan P.
Large multilayer neural networks trained with backpropagation have recently achieved state-of-the-art results in a wide range of problems. However, using backprop for neural net learning still has some disadvantages, e.g., having to tune a large number of hyperparameters to the data, lack of calibrated probabilistic predictions, and a tendency to overfit the training data. In principle, the Bayesian approach to learning neural networks does not have these problems. However, existing Bayesian techniques lack scalability to large dataset and network sizes. In this work we present a novel scalable method for learning Bayesian neural networks, called probabilistic backpropagation (PBP). Similar to classical backpropagation, PBP works by computing a forward propagation of probabilities through the network and then doing a backward computation of gradients. A series of experiments on ten real-world datasets show that PBP is significantly faster than other techniques, while offering competitive predictive abilities. Our experiments also show that PBP provides accurate estimates of the posterior variance on the network weights.
Joint Tensor Factorization and Outlying Slab Suppression with Applications
Fu, Xiao, Huang, Kejun, Ma, Wing-Kin, Sidiropoulos, Nicholas D., Bro, Rasmus
We consider factoring low-rank tensors in the presence of outlying slabs. This problem is important in practice, because data collected in many real-world applications, such as speech, fluorescence, and some social network data, fit this paradigm. Prior work tackles this problem by iteratively selecting a fixed number of slabs and fitting, a procedure which may not converge. We formulate this problem from a group-sparsity promoting point of view, and propose an alternating optimization framework to handle the corresponding $\ell_p$ ($0
A Scalable Interdependent Multi-Issue Negotiation Protocol for Energy Exchange
Alam, Muddasser (University of Southampton) | Gerding, Enrico H. (University of Southampton) | Rogers, Alex (University of Southampton) | Ramchurn, Sarvapali D. (University of Southampton)
To address We present a novel negotiation protocol to facilitate this challenge, Alam et al. [2013b] presented a protocol to energy exchange between off-grid homes that facilitate negotiation over energy exchange. Their protocol are equipped with renewable energy generation and restricts the type and number of offers such that negotiation electricity storage. Our protocol imposes restrictions leads to a subgame perfect Nash equilibrium (SPNE). However, over negotiation such that it reduces the complex their protocol only allows point-to-point communication interdependent multi-issue negotiation to one and relies on a fully connected network topology (i.e., where agents have a strategy profile in subgame each home is connected to all other homes in the community) perfect Nash equilibrium. We show that our protocol whereby the number of connections and messages exchanged; is concurrent, scalable and; under certain conditions; grow quadratically with the number of connected leads to Pareto-optimal outcomes.
Robust Learning for Repeated Stochastic Games via Meta-Gaming
Crandall, Jacob W. (Masdar Institute of Science and Technology)
In repeated stochastic games (RSGs), an agent must quickly adapt to the behavior of previously unknown associates, who may themselves be learning. This machine-learning problem is particularly challenging due, in part, to the presence of multiple (even infinite) equilibria and inherently large strategy spaces. In this paper, we introduce a method to reduce the strategy space of two-player general-sum RSGs to a handful of expert strategies. This process, called mega, effectually reduces an RSG to a bandit problem. We show that the resulting strategy space preserves several important properties of the original RSG, thus enabling a learner to produce robust strategies within a reasonably small number of interactions. To better establish strengths and weaknesses of this approach, we empirically evaluate the resulting learning system against other algorithms in three different RSGs.
A Crowdfunding Model for Green Energy Investment
Zheng, Ronghuo (Carnegie Mellon University) | Xu, Ying (Carnegie Mellon University) | Chakraborty, Nilanjan (Stony Brook University) | Sycara, Katia (Carnegie Mellon University)
This paper studies a new renewable energy investment model through crowdfunding, which is motivated by emerging community solar farms. In this paper we develop a sequential game theory model to capture the interactions among crowdfunders, the solar farm owner, and an electricity company who purchases renewable energy generated by the solar farm in a multi-period framework. By characterizing a unique subgame-perfect equilibrium, andcomparing it with a benchmark model without crowdfunding, we find that under crowdfunding although the farm owner reduces its investment level, the overall green energy investment level is increased due to the contribution of crowdfunders. We also find that crowdfunding can increase the penetration of green energy in consumption and thus reduce the energy procurement cost of the electricity company. Finally, the numerical results based on real data indicates crowdfunding is a simple but effective way to boost green generation.
Copula Graphical Models for Wind Resource Estimation
Veeramachaneni, Kalyan (Massachusetts Institute of Technology) | Cuesta-Infante, Alfredo (Universidad Rey Juan Carlos) | O' (Massachusetts Institute of Technology) | Reilly, Una-May
We develop multivariate copulas for modeling multiple joint distributions of wind speeds at a wind farm site and neighboring wind source. A ndimensional Gaussian copula and multiple copula graphical models enhance the quality of the prediction site distribution. The models, in comparison to multiple regression, achieve higher accuracy and lower cost because they require less sensing data.
Approximately Stable Pricing for Coordinated Purchasing of Electricity
Perrault, Andrew (University of Toronto) | Boutilier, Craig (University of Toronto)
Matching markets are often used in exchange settings (e.g., supply chain) to increase economic efficiency while respecting certain global constraints on outcomes. We investigate their application to pricing and cost sharing in group purchasing of electricity in smart grid settings. The task is complicated by the complexities of producer cost functions due to constraints on generation from different sources (they are sufficiently complex that welfare-optimal matchings are not usually in equilibrium). We develop two novel cost sharing schemes: one based on Shapley values that is "fair," but computationally intensive; and one that captures many of the essential properties of Shapley pricing, but scales to large numbers of consumers. Empirical results show these schemes achieve a high degree of stability in practice and can be made more stable by sacrificing small amounts (< 2%) of social welfare.
On the Balance of Meter Deployment Cost and NILM Accuracy
Hao, Xiaohong (Tsinghua University) | Tang, Bangsheng (Hulu LLC) | Wang, Yongcai (Tsinghua University)
Non-Intrusive Load Monitoring (NILM) uses one smart meter at the power feed to disaggregate the states of a set of appliances. Multiple NILM meters are deployed to achieve high monitoring accuracy in large-scale power systems. Our work studies the tradeoff between monitoring accuracy and meter deployment, in a quantitative and extensible way. In particular, we introduce a clearness function as an abstract indicator of expected monitoring accuracy given any NILM method, and then showcase two concrete constructions. With the notation of a clearness function, we propose solutions to the smart meter deployment problem (SMDP), that is, the problem of finding a deployment scheme with minimum number of meters while attaining a required monitoring accuracy. Theoretically, SMDP is shown NP-hard and a polynomial-time approximation scheme (PTAS) is proposed in this paper. For evaluation, we show that our proposed scheme is efficient and effective in terms of approximation ratio and running time. On real and simulated datasets, our proposed framework achieves a higher monitoring accuracy at a much lower cost, outperforming common baseline algorithms.
Modeling Multi-Attribute Demand for Sustainable Cloud Computing with Copulae
Ghasemi, Maryam (Boston University) | Lubin, Benjamin (Boston University)
As cloud computing gains in popularity, understanding the patterns and structure of its loads is increasingly important in order to drive effective resource allocation, scheduling and pricing decisions. These efficiency increases are then associated with a reduction in the data center environmental footprint. Existing models have only treated a single resource type, such as CPU, or memory, at a time. We offer a sophisticated machine learning approach to capture the joint-distribution. We capture the relationship among multiple resources by carefully fitting both the marginal distributions of each resource type as well as the non-linear structure of their correlation via a copula distribution. We investigate several choices for both models by studying a public data set of Google data-center usage. We show the Burr XII distribution to be a particularly effective choice for modeling the marginals and the Frank copula to be the best choice for stitching these together into a joint distribution. Our approach offers a significant fidelity improvement and generalizes directly to higher dimensions. In use, this improvement will translate directly to reductions in energy consumption.