Active Learning with Expert Advice

Conventional learning with expert advice methods assumes a learner is always receiving the outcome (e.g., class labels) of every incoming training instance at the end of each trial. In real applications, acquiring the outcome from oracle can be costly or time consuming. In this paper, we address a new problem of active learning with expert advice, where the outcome of an instance is disclosed only when it is requested by the online learner. Our goal is to learn an accurate prediction model by asking the oracle the number of questions as small as possible. To address this challenge, we propose a framework of active forecasters for online active learning with expert advice, which attempts to extend two regular forecasters, i.e., Exponentially Weighted Average Forecaster and Greedy Forecaster, to tackle the task of active learning with expert advice. We prove that the proposed algorithms satisfy the Hannan consistency under some proper assumptions, and validate the efficacy of our technique by an extensive set of experiments.Comment: Appears in Proceedings of the Twenty-Ninth Conference on Uncertainty in Artificial Intelligence (UAI2013

Swing Dynamics as Primal-Dual Algorithm for Optimal Load Control

Frequency regulation and generation-load balancing are key issues in power transmission networks. Complementary to generation control, loads provide flexible and fast responsive sources for frequency regulation, and local frequency measurement capability of loads offers the opportunity of decentralized control. In this paper, we propose an optimal load control problem, which balances the load reduction (or increase) with the generation shortfall (or surplus), resynchronizes the bus frequencies, and minimizes a measure of aggregate disutility of participation in such a load control. We find that, a frequency-based load control coupled with the dynamics of swing equations and branch power flows serve as a distributed primal-dual algorithm to solve the optimal load control problem and its dual. Simulation shows that the proposed mechanism can restore frequency, balance load with generation and achieve the optimum of the load control problem within several seconds after a disturbance in generation. Through simulation, we also compare the performance of optimal load control with automatic generation control (AGC), and discuss the effect of their incorporation

A Pilot Stability Study of Dehydroepiandrosterone Rapid-dissolving Tablets Prepared by Extemporaneous Compounding

Dehydroepiandrosterone supplementation is used to treat a variety of conditions. Rapid-dissolving tablets are a relatively novel choice for compounded dehydroepiandrosterone dosage forms. While rapid-dissolving tablets offer ease of administration, there are uncertainties about the physical and chemical stability of the drug and dosage form during preparation and over long-term storage. This study was designed to evaluate the stability of dehydroepiandrosterone rapid-dissolving tablets just after preparation and over six months of storage. The Professional Compounding Centers of America rapid-dissolving tablet mold and base formula were used to prepare 10-mg strength dehydroepiandrosterone rapid-dissolving tablets. The formulation was heated at 100°C to 110°C for 30 minutes, released from the mold, and cooled at room temperature for 30 minutes. The resulting rapid-dissolving tablets were individually packaged in amber blister packs and stored in a stability chamber maintained at 25°C and 60% relative humidity. The stability samples were pulled at pre-determined time points for evaluation, which included visual inspection, tablet weight check, United States Pharmacopeia disintegration test, and stability-indicating high-performance liquid chromatography. The freshly prepared dehydroepiandrosterone rapiddissolving tablets exhibited satisfactory chemical and physical stability. Time 0 samples disintegrated within 40 seconds in water kept at 37°C. The highperformance liquid chromatographic results confirmed that the initial potency was 101.9% of label claim and that there was no chemical degradation from the heating procedure. Over six months of storage, there were no significant changes in visual appearance, physical integrity, or disintegration time for any of the stability samples. The high-performance liquid chromatographic results also indicated that dehydroepiandrosterone rapid-dissolving tablets retained \u3e95% label claim with no detectable degradation products. The dehydroepiandrosterone rapid-dissolving tablets investigated in this pilot study were physically and chemically stable during preparation and over six months of storage at 25°C and 60% relative humidity

Fast Load Control with Stochastic Frequency Measurement

Matching demand with supply and regulating frequency are key issues in power system operations. Flexibility and local frequency measurement capability of loads offer new regulation mechanisms through load control. We present a frequency-based fast load control scheme which aims to match total demand with supply while minimizing the global end-use disutility. Local frequency measurement enables loads to make decentralized decisions on their power from the estimates of total demand-supply mismatch. To resolve the errors in such estimates caused by stochastic frequency measurement errors, loads communicate via a neighborhood area network. Case studies show that the proposed load control can balance demand with supply and restore the frequency at the timescale faster than AGC, even when the loads use a highly simplified system model in their algorithms. Moreover, we discuss the tradeoff between communication and performance, and show with experiments that a moderate amount of communication significantly improves the performance

From Sugar To Acetate - The Origins Of Acetyl-Coa Dictate Its Use In Cells And In Mice

Changes in environmental factors, diet, and genetics all influence metabolism, which is frequently dysregulated at the cellular and organismal levels in diseases such as metabolic syndrome, cancer, and inborn errors of metabolism. These maladies are often intertwined; for example, metabolic diseases such as obesity and inborn errors of metabolism such as fumarate hydratase deficiency can both increase the risk for developing certain cancers. One metabolic pathway frequently altered in disease is de novo lipogenesis (DNL). Aberrant DNL is believed to play a critical role in pathogenesis of cancer and non-alcoholic fatty liver disease (NAFLD), a manifestation of metabolic syndrome in the liver. DNL requires the metabolite, acetyl-CoA, which is predominantly synthesized in the cytosol and nucleus from the cleavage of citrate through the action of ATP-citrate lyase (ACLY). Consistent with its role in DNL, elevated levels or activity of ACLY is frequently observed in cancer and NAFLD. Therefore, I utilized a genetic loss-of-function approach coupled with metabolomic methods to investigate how abrogating ACLY impacts metabolism in proliferating cells and the liver. Unexpectedly, impairment of ACLY leads to metabolic compensation through ACSS2-dependent acetate usage at the cellular and tissue levels. Moreover, by depleting ACLY, we identify a link between dietary carbohydrate and microbiome-derived acetate in supporting hepatic DNL. These findings have revised our understanding of acetyl-CoA metabolism in cells, and how nutritional sources feed into this pathway in disease contexts