On the iterated forms of Kalman filters using statistical linearization

The extended Kalman filter (EKF) is a suboptimal estimator of the conditional mean and covariance for nonlinear state estimation. It is based on first order Taylor series approximation of nonlinear state functions. The unscented Kalman filter (UKF) and the ensemble Kalman filter (EnKF) are suboptimal estimators that are termed as Jacobian free because they do not require the existence of the Jacobian of the nonlinearity. The iterated form of EKF is an estimator of the conditional mode that employs an approximate Newton–Raphson iterative scheme to solve the maximization of the conditional probability density function. In this paper, the iterated forms of UKF and EnKF are presented that perform Newton–Raphson iteration without explicitly differentiating the nonlinear functions. The use of statistical linearization in iterated UKF and EnKF is a nondifferentiable optimization method when the measurement function is nonsmooth or discontinuous. All three iterated forms can be shown to be conditional mean estimators after the first iteration. A simple numerical example involving continuous and discontinuous measurment functions is included to evaluate the performance of the algorithms for the estimation of conditional mean, covariance and mode. A batch reactor simulation is shown for estimating both the states and unknown parameters.     

Mechanism of titanium sponge formation in the kroll reduction reactor

The Kroll process of magnesium reduction of titanium tetrachloride is used the world over the production of titanium metal in the form of sponge. Although the process has been in practice for the last five decades, there is no clear understanding of the reaction mechanism and sponge formation. The present study involved reduction experiments in a 2000 kg titanium sponge-capacity prototype reactor to develop a better understanding of TiCl₄ reduction of magnesium with respect to the process parameters. Experiments were also conducted in two smaller experimental reactors to study the temperature evolution during the process as a function of the TiCl₄ feed rate. Based on the results of all these experiments, a model has been proposed for the mechanism of sponge formation in the Kroll process.     

Design space exploration for real-time embedded stream processors

We explore tradeoffs between organization and number of ALUs and clock frequency in a stream processor. The tool provides candidate low-power configurations and estimates of their real-time performance. The tool relates instruction-level, subword, and data parallelism to functional units' organization and utilization. The exploration methodology is applicable to all embedded-processor designs in signal and media processing.     

Graph structure in the Web

The study of the Web as a graph is not only fascinating in its own right, but also yields valuable insight into Web algorithms for crawling, searching and community discovery, and the sociological phenomena which characterize its evolution. We report on experiments on local and global properties of the Web graph using two AltaVista crawls each with over 200 million pages and 1.5 billion links. Our study indicates that the macroscopic structure of the Web is considerably more intricate than suggested by earlier experiments on a smaller scale.     

Multiple metastatic infections in a hemodialysis patient with untunneled internal jugular catheter

We present an end‐stage renal disease patient on dialysis with fever. The primary source was right internal jugular vein catheter which had metastatic infections in the body probably via an arteriovenous communication in a cavity in left lung. Patient had right psoas muscle abscess and a left kidney abscess. An ¹⁸F‐fluorodeoxyglucose‐positron emission spectroscopy scan was done to find out left kidney abscess. A search of literature did not reveal many patients of psoas abscess secondary to infection of hemodialysis access.     

Strategic effort allocation in online innovation tournaments

Online innovation tournaments, such as those hosted by crowdsourcing platforms (e.g., Kaggle), have been widely adopted by firms to evolve creative solutions to various problems. Solvers compete in these tournaments to earn rewards. In such competitive environments, it is imperative that solvers provide creative solutions with minimum effort. This article explores the factors that influence the solvers’ effort allocation decisions in a dynamic tournament setting. Specifically, comprehensive time variant data of teams that participated in crowdsourcing competitions on Kaggle were analyzed to gain insight into how solvers continually formulate strategies in light of performance feedback obtained through interim ranking. The results suggest that solvers strategically allocate their efforts throughout the contest to dynamically optimize their payoffs through balancing the probability of winning and the cost of expending effort. In particular, solvers tend to increase their efforts toward the end of tournaments or when they get closer to winning positions. Furthermore, our findings indicate that a last-minute surge in effort is more prevalent among high-skill solvers than in those with lower skill levels. In addition to providing insights that may help solvers develop strategies to improve their performance, the study has implications for the design of online crowdsourcing platforms, particularly in terms of incentivizing solvers to put forth their best effort.     

Behaviour of CI engine performance,combustion and exhaust emission with neem biodiesel at varied fuel injection rates

Motorisation and fast depletion of fossil fuel reserves and issues like global warming have led the researchers all over to look for substitute fuels. Biodiesel resulting from vegetable oil is being used around the globe to lessen air pollution and reduce the necessity of diesel fuel. The current study covers the various aspects of N20 neem biodiesel with increased fuel injection pressure. The blends of N20 were tested with increased fuel injection pressure to examine the characteristics such as brake thermal efficiency, fuel consumption, emission and combustion parameters. Experimental results indicated that N20 with 240?bar has a closer performance to diesel, reduced exhaust emission and improved combustion parameters.     

Quaternized poly(phenylene oxide) anion exchange membrane for alkaline direct methanol fuel cells in KOH‐free media

A series of anion exchange membrane (AEM) electrolytes with quaternary ammonium moiety are fabricated from poly (phenylene oxide) for its application in alkaline direct methanol fuel cells (ADMFCs). In the first step, poly(phenylene oxide) (PPO) is successfully chloromethylated by substituting chloromethyl groups in the aryl position of polymer. In the second step, the chloromethylated PPO (CPPO) is further homogeneously quaternized and ion‐exchanged to form an AEM. From the second step, series of AEMs are prepared by changing the mole ratio of amine in relation to CPPO. The presence of quaternary ammonium group in the membrane was confirmed by elemental analysis. The fabricated membranes are subjected to cell polarization studies in ADMFCs, wherein quaternized poly(2,6‐dimethyl‐1,4‐phenylene oxide) (CPPO:amine of 1:8) membrane exhibits higher peak power density of 3.5 mW cm^?2 when compared with the other ratios of CPPO:amine in the absence of KOH solution. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43693.