Worcester Polytechnic Institute

About: Worcester Polytechnic Institute is a education organization based out in Worcester, Massachusetts, United States. It is known for research contribution in the topics: Computer science & Population. The organization has 6270 authors who have published 12704 publications receiving 332081 citations. The organization is also known as: WPI.

Statistical approach for the detection of motion/noise artifacts in Photoplethysmogram

Abstract: Motion and noise artifacts (MNA) have been a serious obstacle in realizing the potential of Photoplethysmogram (PPG) signals for real-time monitoring of vital signs. We present a statistical approach based on the computation of kurtosis and Shannon Entropy (SE) for the accurate detection of MNA in PPG data. The MNA detection algorithm was verified on multi-site PPG data collected from both laboratory and clinical settings. The accuracy of the fusion of kurtosis and SE metrics for the artifact detection was 99.0%, 94.8% and 93.3% in simultaneously recorded ear, finger and forehead PPGs obtained in a clinical setting, respectively. For laboratory PPG data recorded from a finger with contrived artifacts, the accuracy was 88.8%. It was identified that the measurements from the forehead PPG sensor contained the most artifacts followed by finger and ear. The proposed MNA algorithm can be implemented in real-time as the computation time was 0.14 seconds using Matlab®.

A synthetic study of sourcing strategies

Abstract: As more evidence indicates that a corporation is very much defined by its purchases and benefited by its close partnership with the suppliers, the sourcing decision becomes increasingly important in the firm’s growth and profit. This paper synthesizes the available sourcing alternatives into four categories, namely multiple sourcing, single sourcing, single/dual hybrid or network sourcing, and global sourcing, and provides a comprehensive review of these purchasing methods based on extensive literature. Besides the discussion of the pros and cons, the paper focuses on the underlying factors that determine the preference and suitability of each sourcing option. In addition, with the note that numerous companies are switching to do business on a global basis, we attempt to use China as an example to examine global sourcing from the standpoints of both buyer and supplier.

Robust detection and accommodation of incipient component and actuator faults in nonlinear distributed processes

Abstract: A class of nonlinear distributed processes with component and actuator faults is presented. An adaptive detection observer with a time varying threshold is proposed that provides additional robustness with respect to false declarations of faults and minimizes the fault detection time. Additionally, an adaptive diagnostic observer is proposed that is subsequently utilized in an automated control reconfiguration scheme that accommodates the component and actuator faults. An integrated optimal actuator location and fault accommodation scheme is provided in which the actuator locations are chosen in order to provide additional robustness with respect to actuator and component faults. Simulation studies of the Kuramoto-Sivashinsky nonlinear partial differential equation are included to demonstrate the proposed fault detection and accommodation scheme. © 2008 American Institute of Chemical Engineers AIChE J, 2008

On the accuracy of RF and image processing based hybrid localization for wireless capsule endoscopy

Abstract: RF based and image processing based hybrid localization for wireless capsule endoscopy (WCE) has been adopted as one of the leading in-body localization approach for its overwhelming advantage on the accuracy of location estimation. In this paper, in order to investigate the fundamental limits, we derived the 3-dimensional (3D) Posterior Cramer-Rao Lower Bound (PCRLB) for hybrid WCE localization with the knowledge of RF based range estimation and image processing based step length and heading measurements. In addition to the PCRLB derivation, numerical results of this work shows that when the accuracy of image processing based measurement is high enough or the number of on-body RF receiver is large enough, the root-mean-square error (RMSE) of hybrid WCE localization can be limited within 3cm.

Generation of terahertz radiation by optical excitation of aligned carbon nanotubes.

Abstract: We have generated coherent pulses of terahertz radiation from macroscopic arrays of aligned single-wall carbon nanotubes (SWCNTs) excited by femtosecond optical pulses without externally applied bias. The generated terahertz radiation is polarized along the SWCNT alignment direction. We propose that top-bottom asymmetry in the SWCNT arrays produces a built-in electric field in semiconducting SWCNTs, which enables generation of polarized terahertz radiation by a transient photocurrent surge directed along the nanotube axis.