Discrete time adaptive control for a MEMS gyroscope

This paper presents a discrete time version of the observer‐based adaptive control system for micro‐electro‐mechanical systems gyroscopes, which can be implemented using digital processors. A stochastic analysis of this control algorithm is developed and it shows that the estimates of the angular rate and the fabrication imperfections are biased due to the signal discretization errors in the feedforward control path introduced by the sampler and holder. Thus, a two‐rate discrete time control is proposed as a compromise between the measurement biases and the computational burden imposed on the controller. The convergence analysis of this algorithm is also conducted and an analysis method is developed for determining the trade‐off between the controller sampling frequency and the magnitude of the angular rate estimate biased errors. All convergence and stochastic properties of a continuous time adaptive control are preserved, and this analysis is verified with computer simulations. Copyright © 2005 John Wiley & Sons, Ltd.     

Humidifier disinfectant and use characteristics associated with lung injury in Korea

Since around the year 2000, hundreds of people in Korea have developed humidifier disinfectant‐associated lung injury (HDLI). We collected all HD exposure‐related information from the field investigations into the locations in which the 1199 registered patients had used HD. Among the people who registered, 38% (1st round = 214, 2nd = 73, 3rd = 166) were confirmed as HDLI patients. Children aged under eight years old made up the highest proportion of HDLI cases (N = 279, 62%), followed by pregnant women (N = 31, 7%). One hundred thirty‐three (29%) of the confirmed HDLI patients died. Fifty‐seven percent of HDLI patients (N = 259) developed HDLI after <1 year of HD use. The number of HDLI patients who used only the Oxy Saksak HD brand was found to be 176 (39%), followed by the brands Cefu (N = 27, 6%) and Aekyung (N = 22, 5%). HD products containing only polyhexamethylene guanidine phosphate (PHMG‐P) were the most frequently used among HDLI patients (N = 234, 52%), followed by oligo (2‐(2‐ethoxy)ethoxyethyl) guanidinium (PGH) (N = 27, 6%) and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (N = 26, 6%). The average PHMG‐P inhalation level estimated from the patient group classified as suffering lung injury definitely associated with HD use was 145.1 μg/m³ (N = 91, SD = 395.1 μg/m³), higher than levels estimated from both the probable and possible HDLI patient groups. In conclusion, HD exposure‐related variables, including type of HD brand and estimated inhalation HD level, were associated with the risk of HDLI.     

Rule mining for scheduling cross training with a heterogeneous workforce

This paper presents an association rule mining based framework for workforce scheduling to assist managers with robust real-time assignment decisions. We assume heterogeneous individual learning and forgetting behaviours, in which worker productivity changes dynamically. We explore a parallel production system that meets a specified production requirement over a fixed time horizon with the minimum workforce resources based on the number of worker-periods assigned. Three managerial policies are considered including: setting a maximum allowable individual cross-training level, balancing workload among workers and an unconstrained policy. We propose the use of several schedule attributes to quantify key aspects of optimised schedules that may, in turn, aid in determining robust assignment rules and the development of better cross-training policies. Current results indicate that the proposed approach is effective at identifying important rules, many of which add to our knowledge of useful workforce scheduling strategies.     

Effect of over/under-expanding on the mechanical behavior in provisional stenting using bioresorbable scaffold

The purpose of this study is to contribute to the design and development by analyzing the expected mechanical behavior of bioresorbable scaffolds. Bioresor     

Study on durability and reliability of strut type suspension noise based on experimental methods

When cars are released from the factory, strut noises are very small and therefore it is difficult to perceive them. As the use time and travel distance increase, however, strut noises get larger so as to cause users much uneasiness. The noises generated at the field include engine noises and flow noises and therefore it is difficult to clearly discern the noises generated from struts. This study developed a test method which can reproduce field strut noises in the lab. Using the newly developed noise evaluation test, this study analyzed the effects that insulator performance degradation and failure can have on car noises. The study also confirmed that the insulator durability test by the simple back-and-forth motion cannot completely reflect the state of the parts failure in the field. Based on this, the study also confirmed that field noises can be reproduced through a durability test that considers heat aging.     

A study on multimedia file carving method

File carving is a method that recovers files at unallocated space without any file information and used to recover data and execute a digital forensic investigation. In general, the file carving recovers files using the inherent header and footer in files or the entire file size determined in the file header. The largely used multimedia files, such as AVI, WAV, and MP3, can be exactly recovered using an internal format in files as they are continuously allocated. In the case of the NTFS, which is one of the most widely used file system, it supports an internal data compression function itself, but the NTFS compression function has not been considered in file carving. Thus, a large part of file carving tools cannot recover NTFS compressed files. Also, for carving the multimedia files compressed by the NTFS, a recovery method for such NTFS compressed files is required. In this study, we propose a carving method for multimedia files and represent a recovery plan for deleted NTFS compressed files. In addition, we propose a way to apply such a recovery method to the carving of multimedia files.     

Optimal conditions for recovering boron from seawater using boron selective resins

We determined the optimal conditions for efficient recovery of boron from seawater using boron selective resins (BSRs). A commercialized BSR named CRB05 was adopted and prepared in two particle sizes: A fine-particulate BSR (effective particle size of 105 μm) and a coarse-particulate BSR (effective particle size of 445 μm). The performance of the two BSRs was compared in terms of boron adsorption, boron desorption, and BSR regeneration and reusability. During boron adsorption, for fine BSR, optimal reaction time, stirring speed and the amount of BSR needed for the adsorption of boron were 30 min, 150 rpm and 1 g-BSR/L respectively, whereas for coarse BSR, values of the above parameters were 300 min, 150 rpm and 3 g-BSR/L. It indicates that the fine BSR can adsorb boron about threetimes more than the coarse BSR. It also shows that the reaction rate of the fine BSR is almost ten-times higher than that of the coarse BSR. During the boron desorption, no significant difference was found between the efficiencies exhibited by the fine and the coarse BSRs. The best desorption performance can be attained with 11.9 mL/mg-B of 0.05 M H₂SO₄ and 15.9mL/mg-B of 0.25M HCl, regardless of the particle size of the BSR. Finally, the boron adsorption efficiency can be maintained at a stable level even after reusing the BSRs over ten times. The present study shows a possibility to recover boron with better efficiency from seawater in short time using the fine BSR, rather than the coarse BSR.     

Immunoliposomes Sandwich Fluorometric Assay (ILSF) for Detection of Escherichia coli O157:H7

ABSTRACT: We report the development of automated flourometric immunoassay for the detection of Escherichia coli O157:H7, using antibody-directed liposomes (immunoliposomes) encapsulating fluorophore as an analytical reagent. Thiolated antibodies (anti- E. coli O157:H7) were coupled to malemide-tagged liposomes encapsulating dye. To automate the assay, a fluorescence plate reader was included in the assay system to detect fluorophore released from lysed liposomes in a microplate. The detection limit of the current assay with pure cultures of the serotype was about 10⁴ colony-forming units (CFU)/mL. The assay can detect E. coli O157 in ground beef samples inoculated with as few as 0.8 CFU/mL after a 12-h enrichment. These results demonstrate the feasibility of using fluorophore-encapsulated immunoliposomes in a microtiter plate for the rapid and automated detection of molecules with multivalent antigenic sites.