1,539 research outputs found

    Approximation Algorithms for Correlated Knapsacks and Non-Martingale Bandits

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    In the stochastic knapsack problem, we are given a knapsack of size B, and a set of jobs whose sizes and rewards are drawn from a known probability distribution. However, we know the actual size and reward only when the job completes. How should we schedule jobs to maximize the expected total reward? We know O(1)-approximations when we assume that (i) rewards and sizes are independent random variables, and (ii) we cannot prematurely cancel jobs. What can we say when either or both of these assumptions are changed? The stochastic knapsack problem is of interest in its own right, but techniques developed for it are applicable to other stochastic packing problems. Indeed, ideas for this problem have been useful for budgeted learning problems, where one is given several arms which evolve in a specified stochastic fashion with each pull, and the goal is to pull the arms a total of B times to maximize the reward obtained. Much recent work on this problem focus on the case when the evolution of the arms follows a martingale, i.e., when the expected reward from the future is the same as the reward at the current state. What can we say when the rewards do not form a martingale? In this paper, we give constant-factor approximation algorithms for the stochastic knapsack problem with correlations and/or cancellations, and also for budgeted learning problems where the martingale condition is not satisfied. Indeed, we can show that previously proposed LP relaxations have large integrality gaps. We propose new time-indexed LP relaxations, and convert the fractional solutions into distributions over strategies, and then use the LP values and the time ordering information from these strategies to devise a randomized adaptive scheduling algorithm. We hope our LP formulation and decomposition methods may provide a new way to address other correlated bandit problems with more general contexts

    QCD Physics at Tevatron

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    Proposal to look for an up/down asymmetry in atmospheric neutrinos beyond Multi-GeV region with existing experimental data

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    We discuss a possible test of neutrino oscillation hypothesis by proposing the combined analysis of high energy atmospheric neutrino induced muon events that have been detected around horizontal direction in the Kolar Gold Field (KGF) underground site and below the horizontal direction by many large detectors such as Super-Kamiokande and MACRO. Up/down asymmetry obtained using contained events recorded by detectors at Kamioka site probes low energy region of atmospheric neutrino whereas, the suggested method probes high energy neutrinos. It mainly depends on the observations and it is free of uncertainties in neutrino flux, interaction cross section etc. In this paper we demonstrate that the method is sensitive to a region of oscillation parameter space that explains all the features of atmospheric neutrino data in the Super-Kamiokande detector; the limiting factor being the statistical strength of the KGF observations. This method provides the only way to study the up/down asymmetry beyond Multi-GeV region which is yet to be measured experimentally.Comment: revtex, 6 pages with 3 eps figures. Error introduced by the different low-energy thresholds assessed, conclusion unchange

    Task-based agricultural mobile robots in arable farming: A review

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    In agriculture (in the context of this paper, the terms “agriculture” and “farming” refer to only the farming of crops and exclude the farming of animals), smart farming and automated agricultural technology have emerged as promising methodologies for increasing the crop productivity without sacrificing produce quality. The emergence of various robotics technologies has facilitated the application of these techniques in agricultural processes. However, incorporating this technology in farms has proven to be challenging because of the large variations in shape, size, rate and type of growth, type of produce, and environmental requirements for different types of crops. Agricultural processes are chains of systematic, repetitive, and time-dependent tasks. However, some agricultural processes differ based on the type of farming, namely permanent crop farming and arable farming. Permanent crop farming includes permanent crops or woody plants such as orchards and vineyards whereas arable farming includes temporary crops such as wheat and rice. Major operations in open arable farming include tilling, soil analysis, seeding, transplanting, crop scouting, pest control, weed removal and harvesting where robots can assist in performing all of these tasks. Each specific operation requires axillary devices and sensors with specific functions. This article reviews the latest advances in the application of mobile robots in these agricultural operations for open arable farming and provide an overview of the systems and techniques that are used. This article also discusses various challenges for future improvements in using reliable mobile robots for arable farmin

    Development of Bioresponsive Chronopharmaceutical Drug Delivery System in Treatment of Asthma & Copd Using Colon Targeted Mucoadhesive Tablets in Capsule System

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    AIM & OBJECTIVES : The main aim of the project was to develop a delivery system that claims the futuristic approach in the field of pharmaceutical science based on bioresponsiveness and timed delivery of drugs into the body. The objective of the present study is to develop the delivery system and to evaluate its delivery profile based on triggered release, timed release and site targeting. Salbutamol sulphate was chosen as the model drug for the present study to designa dosage form for treatment of asthma. Carbopol 971 P and eudragit E was chosen as key ingredients in the formulation to attain goal in this study. The development of tablets-filled-capsule systems offer benefits for the production of sustained release multiple unit dosage form. This system has specific advantages over conventional single unit dosage forms. Advantages of multiple unit dosage forms such as Mini-tablet-in capsule systems include a lower risk of dose dumping, less inter and intra such variability and a high degree of dispersion in the digestive tract, thus minimizing the risks of high local drug concentrations. Oral drug delivery represents by far the most common & convenient way of drug delivery. The gastro-Intestinal tract is still the route of choice for drug administration & absorption. Chronopharmaceutics is a branch of pharmaceutics devoted to design and evaluation of drug delivery system that release a bioactive agent at a rhythm that ideally matches the biological requirement of a given disease therapy. Ideally chronopharmaceutical drug delivery system (ChrDDS) should embody time controlled and site specific drug delivery system. A Bioresponsive drug delivery system is necessary since it works on the mechanisms capable of responding to physiological variations in the body, in order to synchronize drug- release profiles with changing physiological conditions.CONCLUSION: Chronopharmaceutical drug delivery can be used in case of diseases which shows circadian rhythm in their patho physiology which can tackle the problems as it is modulated to release the drug according to the biological clock. Hence, a smarter drug delivery system is needed which alters drug release profile itself based on severity of asthma attacks and COPD. This benefits the maintenance of drugs in plasma and also releases more of the drug it holds when condition is severe based on the needs of the physiological system

    Limits on monopole fluxes from KFG experiment

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    The nucleon decay experiment at KGF at a depth of 2.3 Km is eminently suited for the search of Grand Unified theory (GUT) monopoles, whose velocities at the present epoch are predicted to be around 0.001C. At this depth the cosmic ray background is at a level 2/day in the detector of size 4m x 6m x 3.7m and one can look for monopoles traversing the detector in all directions, using three methods, i.e., (1) dE/dx (ionization); (2) time of flight and (3) catalysis of nucleon decay. The detector is composed of 34 layers of proportional counters arranged in horizontal planes one above the other in an orthogonal maxtrix. Each of the 1594 counters are instrumented to measure ionization in the gas (90% Argon + 10% Methane) as well as the time of arrival of particles

    Stakeholder engagement in hydro-climatic services in India: report of pump priming project April 2019

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    The India-UK Water Centre (IUKWC) promotes cooperation and collaboration between the complementary priorities of NERC-MoES water security research. This report presents an overview of a research project funded as a pump priming activity by the India-UK Water Centre (IUKWC), carried out between July–October 2017. Project activities included: a webinar, a desk-based literature review, a series of expert interviews and a participatory workshop held at the Indian Institute of Tropical Meteorology, Pune, in September 2017. The research was led by Dr Zareen Pervez Bharucha (Anglia Ruskin University), who worked with a team of scholars from the UK and India. This report outlines the key activities undertaken during the project, gives an overview of our research methods, and outlines the main findings. It is intended for participants in the research process, members of the India-UK Water Centre, and other stakeholders who have an interest in developing hydro-climatic services in India or comparable contexts. It should be read in conjunction with a State of the Science brief available on the IUKWC website (www.iukwc.org)

    Soil-Pile Interaction Parameters in Vertical and Torsional Vibrations

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    In this paper, two lumped parameter analogues with the inclusion of constant friction damping are suggested to explain the dynamic behavior of pile supported footings during vertical as well as torsional modes of vibrations. Simple theoretical procedures have been described by which the constant frictional force and the constant frictional moment of the friction damping can be evaluated during vertical and torsional vibrations respectively. The suggested procedures into consideration the relevant physical characteristics of the interface between the pile and the soil, as also the length to diameter (L/d) ratio of the pile. Field vibratory teats have been carried out on model pile supported footings under steady state vertical and torsional excitation. The test data obtained are compared with the values predicted by the proposed theory and the agreement between the two is found to be satisfactory
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