Arnold diffusion in the dynamics of a 4-machine power system undergoing a large fault

We focus on the seemingly complicated dynamics of a four-machine power system which is undergoing a sudden fault. Adopting a Hamiltonian (energy) formulation, we consider the system as an interconnection of (one degree of freedom) subsystems. Under certain configuration (a star network) and parameter values we establish the presence of Arnold diffusion which entails periodic, almost periodic, and complicated nonperiodic dyanmics all simultaneously present; and erratic transfer of energies between the subsystems. In section 1 we introduce the transient stability problem in a mathematical setting and explain what our results mean in the power systems context. Section 2 provides insights into Arnold diffusion and summarizes its mathematical formulation as in [8], [1]. Section 3 gives conditions for which Arnold diffusion arises on certain energy levels of the swing equations. These conditions are verified analytically in the case when all but one subsystem (machine) undergo relatively small oscillations

A comprehensive study on disease risk predictions in machine learning

Over recent years, multiple disease risk prediction models have been developed. These models use various patient characteristics to estimate the probability of outcomes over a certain period of time and hold the potential to improve decision making and individualize care. Discovering hidden patterns and interactions from medical databases with growing evaluation of the disease prediction model has become crucial. It needs many trials in traditional clinical findings that could complicate disease prediction. Comprehensive survey on different strategies used to predict disease is conferred in this paper. Applying these techniques to healthcare data, has improvement of risk prediction models to find out the patients who would get benefit from disease management programs to reduce hospital readmission and healthcare cost, but the results of these endeavours have been shifted

Modeling the Differences in Counted Outcomes using Bivariate Copula Models: with Application to Mismeasured Counts

This paper makes three contributions. First, it uses copula functions to obtain a flexible bivariate parametric model for nonnegative integer-valued data (counts). Second, it recovers the distribution of the difference in the two counts from a specifed bivariate count distribution. Third, the methods are applied to counts that are measured with error. Specifically we model the determinants of the difference between the self-reported number of doctor visits (measured with error) and true number of doctor visits (also available in the data used).

MULTI-CHANNEL MAC PROTOCOL FOR ENERGY SAVING IN WIRELESS SENSOR NETWORKS

Wireless Sensor Network (WSN) is a self-organizing and distributed collection of small sensor nodes with limited energy are connected wirelessly to the sink, where the information is needed. The significant trait for any Wireless Sensor Network is power consumption since WSNs finds its most of the applications in unsafe, risky areas like Volcano eruption identification, Warfield monitoring, where human intervention is less or not possible at all. Hence designing a protocol with minimum energy consumption as a concern is an important challenge in increasing the lifetime of the sensor networks. Medium Access Control (MAC) Layer of WSN consumes much of the energy as it contains the radio component. Energy problems in MAC layer include collision, idle listening, and protocol overhead. Our Proposed MAC protocol provides solution for the problem of: collision by providing multiple channels; idle listening by providing sleeping mechanism for the nodes other than the active node; overhead by reducing the number of control messages. Avoiding collision results in the decrease in number of retransmissions which consumes more energy, avoiding idle listening problem will fairly increase the lifetime of the sensor node as well as the network’s lifetime and reducing overhead in turn consumes less energy

Comparative Advantage, Complexity and Volatility

Less developed countries tend to experience higher output volatility, a fact that is, in part, explained by their specialization in more volatile sectors. This paper proposes theoretical explanations for this pattern of specialization -- with the complexity of the goods playing a central role. Specifically, less developed countries with low levels of human capital, or alternately, with lower institutional ability to enforce contracts, will specialize in less complex goods which are also characterized by higher levels of output volatility. We provide novel empirical evidence that less complex industries are indeed more volatile.

UNICS - An Unified Instrument Control System for Small/Medium Sized Astronomical Observatories

Although the astronomy community is witnessing an era of large telescopes, smaller and medium sized telescopes still maintain their utility being larger in numbers. In order to obtain better scientific outputs it is necessary to incorporate modern and advanced technologies to the back-end instruments and to their interfaces with the telescopes through various control processes. However often tight financial constraints on the smaller and medium size observatories limit the scope and utility of these systems. Most of the time for every new development on the telescope the back-end control systems are required to be built from scratch leading to high costs and efforts. Therefore a simple, low cost control system for small and medium size observatory needs to be developed to minimize the cost and efforts while going for the expansion of the observatory. Here we report on the development of a modern, multipurpose instrument control system UNICS (Unified Instrument Control System) to integrate the controls of various instruments and devices mounted on the telescope. UNICS consists of an embedded hardware unit called Common Control Unit (CCU) and Linux based data acquisition and User Interface. The Hardware of the CCU is built around the Atmel make ATmega 128 micro-controller and is designed with a back-plane, Master Slave architecture. The Graphical User Interface (GUI) has been developed based on QT and the back end application software is based on C/C++. UNICS provides feedback mechanisms which give the operator a good visibility and a quick-look display of the status and modes of instruments. UNICS is being used for regular science observations since March 2008 on 2m, f/10 IUCAA Telescope located at Girawali, Pune India.Comment: Submitted to PASP, 10 Pages, 5 figure