Sample Efficient Policy Search for Optimal Stopping Domains

Optimal stopping problems consider the question of deciding when to stop an observation-generating process in order to maximize a return. We examine the problem of simultaneously learning and planning in such domains, when data is collected directly from the environment. We propose GFSE, a simple and flexible model-free policy search method that reuses data for sample efficiency by leveraging problem structure. We bound the sample complexity of our approach to guarantee uniform convergence of policy value estimates, tightening existing PAC bounds to achieve logarithmic dependence on horizon length for our setting. We also examine the benefit of our method against prevalent model-based and model-free approaches on 3 domains taken from diverse fields.Comment: To appear in IJCAI-201

Best of Both Worlds in Online Control: Competitive Ratio and Policy Regret

We consider the fundamental problem of online control of a linear dynamical system from two different viewpoints: regret minimization and competitive analysis. We prove that the optimal competitive policy is well-approximated by a convex parameterized policy class, known as a disturbance-action control (DAC) policies. Using this structural result, we show that several recently proposed online control algorithms achieve the best of both worlds: sublinear regret vs. the best DAC policy selected in hindsight, and optimal competitive ratio, up to an additive correction which grows sublinearly in the time horizon. We further conclude that sublinear regret vs. the optimal competitive policy is attainable when the linear dynamical system is unknown, and even when a stabilizing controller for the dynamics is not available a priori

Role of EYCDFA for Optical Communication System

In this paper, performance analysis of Erbium ytterbium co-doped fiber amplifier is presented. 60Gbps single channel link is used with EDFA-EYCDFA cascaded structure. Various parameters like bit error rate (BER), received optical power, Q factor, noise figure and dispersion are used to measure system performance. The signal to noise ratio has been improved by using this optical amplifier. The main objective to present this work is to use the erbium ytterbium co-doped fiber amplifier to achieve higher power, this amplifier is used because it absorb higher amount of energy

GymCam

Worn sensors are popular for automatically tracking exercises. However, a wearable is usually attached to one part of the body, tracks only that location, and thus is inadequate for capturing a wide range of exercises, especially when other limbs are involved. Cameras, on the other hand, can fully track a user's body, but suffer from noise and occlusion. We present GymCam, a camera-based system for automatically detecting, recognizing and tracking multiple people and exercises simultaneously in unconstrained environments without any user intervention. We collected data in a varsity gym, correctly segmenting exercises from other activities with an accuracy of 84.6%, recognizing the type of exercise at 93.6% accuracy, and counting the number of repetitions to within ± 1.7 on average. GymCam advances the field of real-time exercise tracking by filling some crucial gaps, such as tracking whole body motion, handling occlusion, and enabling single-point sensing for a multitude of users.</jats:p

Strong impact of TGF-&#946;1 gene polymorphisms on breast cancer risk in Indian women: a case-control and population-based study

Introduction: TGF-&#946;1 is a multi-functional cytokine that plays an important role in breast carcinogenesis. Critical role of TGF-&#946;1 signaling in breast cancer progression is well documented. Some TGF-&#946;1 polymorphisms influence its expression; however, their impact on breast cancer risk is not clear. Methods: We analyzed 1222 samples in a candidate gene-based genetic association study on two distantly located and ethnically divergent case-control groups of Indian women, followed by a population-based genetic epidemiology study analyzing these polymorphisms in other Indian populations. The c.29C&#62;T (Pro10Leu, rs1982073 or rs1800470) and c.74G&#62;C (Arg25Pro, rs1800471) polymorphisms in the TGF-&#946;1 gene were analyzed using direct DNA sequencing, and peripheral level of TGF-&#946;1 were measured by ELISA. Results: c.29C&#62;T substitution increased breast cancer risk, irrespective of ethnicity and menopausal status. On the other hand, c.74G&#62;C substitution reduced breast cancer risk significantly in the north Indian group (p  =  0.0005) and only in the pre-menopausal women. The protective effect of c.74G&#62;C polymorphism may be ethnicity-specific, as no association was seen in south Indian group. The polymorphic status of c.29C&#62;T was comparable among Indo-Europeans, Dravidians and Tibeto-Burmans. Interestingly, we found that Tibeto-Burmans lack polymorphism at c.74G&#62;C locus as true for the Chinese populations. However, the Brahmins of Nepal (Indo-Europeans) showed polymorphism in 2.08% of alleles. Mean TGF-&#946;1 was significantly elevated in patients in comparison to controls (p&#60;0.001). Conclusion: c.29C&#62;T and c.74G&#62;C polymorphisms in the TGF-&#946;1 gene significantly affect breast cancer risk, which correlates with elevated TGF-&#946;1 level in the patients. The c.29C&#62;T locus is polymorphic across ethnically different populations, but c.74G&#62;C locus is monomorphic in Tibeto-Burmans and polymorphic in other Indian populations